Managing
Lakes
and
Reservoirs
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Managing Lakes
and Reservoirs
Prepared by the
NORTH AMERICAN LAKE MANAGEMENT SOCIETY
Madison, Wisconsin
and
TERRENE INSTITUTE
Alexandria, Virginia
in cooperation with
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Water, Assessment and Watershed Protection Division
Washington, D.C.
Third Edition
2001
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Managing Lakes and Reservoirs
Managing Lakes and Reservoirs was prepared by the North American Lake Management
Society under EPA Cooperative Agreement No. CX-825902-01 -0 and Terrene Institute
under EPA Cooperative Agreement No. CX-8230781 -9. Contents do not necessarily re-
flect the views of EPA, NALMS, or Terrene Institute, nor does the endorsement of prod-
ucts constitute recommendation or endorsement by EPA, NALMS, or Terrene Institute.
Citation: Holdren,C.,W.Jones,and J.Taggart.2001. Managing Lakes and Reservoirs.N.
Am. Lake Manage. Soc. and Terrene Inst., in coop, with Off. Water Assess. Watershed
Prot. Div. U.S. Environ. Prot. Agency, Madison, Wl.
ISBN 1-880686-15-5
EPA 841-B-01-006
©2001
North American Lake Management Society
Terrene Institute
Copies are available from
North American Lake Management Society
P.O. Box 5443
Madison, Wl 53705
phone: (608) 233-2836
fax:(608)233-3186
nalms@nalms.org
www.nalms.org
and the
Terrene Institute
4 Herbert Street
Alexandria, VA 22305
phone: (800) 726-4853
fax: (703) 548-6299
info@terrene.org
www.terrene.org
II
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Preface
Barley straw was cow food when the first edition of this manual was pub-
lished. And focus groups discussed camera lens, not how to control jet ski-
ers. But that was 13 years ago — and The Lake and Reservoir Restoration
Guidance Manual dealt primarily with restoration of our nation's lakes.
This third edition, Managing Lakes and Reservoirs, testifies to the success and
the leadership of EPA's Clean Lakes Program. Since the publication of the first
manual in 1988, hundreds of lakes have been restored, many of them as Clean
Lakes projects and most of them with the assistance of the people who wrote
this book.
Their expertise — based both on academic credentials and years of experi-
ence — has brought them to the consensus that management of lakes and their
watersheds is ongoing — indeed, a forever process to achieve what people who
use the lake want it to be. And those people, whether they live on the lake, drop
their boats or lines in on weekends, occasionally pitch tents around it, or sell bait
and soft drinks to those who do, must drive the management process.
So this manual is written for you, the lake user, by limnologists (look that up
in the Glossary!), engineers, and sociologists who would empower you to care for
your own lake.
Here is the work of nine professionals, reviewed by dozens more — collec-
tively, that's about 500 years of experience. Their expertise ranges from working
with homeowners to modeling lake problems, necessarily dictating chapters that
differ in length and writing style. As editors, we've tried to make them both under-
standable and useful. Enjoy — and consider feeding the barley straw to your lake!
The Editors
ill
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Managing Lakes and Reservoirs
IV
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Contents
PREFACE Ill
ACKNOWLEDGMENTS xi
CHAPTER 1
Overview 1
Who Should Use This Manual? I
How the Manual is Organized 2
Focus of the Manual: Water Quality 4
Making Your Lake Work for You 5
Defining — and Attaining — Desired Uses 5
Causes v. Symptoms: A Major Reason for This Manual 6
Funding for Lake Management Projects 7
Sources of Additional Information 7
Lakes as Resources 8
References 8
CHAPTER 2
Ecological Concepts « 9
Lake and Reservoir Ecosystems 9
Lake Formation and Distribution II
The Lake and Its Watershed 12
Watershed Inputs 13
Watershed Characteristics 18
Lake Morphometry 21
Lakes v. Reservoirs 23
Lake Processes 25
Lake Stratification and Mixing 25
Photosynthesis and Respiration 29
Aquatic Plant Productivity 31
Phytoplankton Community Succession 36
Sedimentation and Decomposition 36
Food Web Structure, Energy Flow, and Nutrient Cycling 38
Eutrophication 41
Ecology's Place in Lake Protection, Restoration, and Management 45
References 46
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Managing Lakes and Reservoirs
CHAPTER 3
Planning: From Goals to Evaluation and Around Again .... 49
Step I: Clarifying Goals 50
Whose Goals? 50
Primary Social Needs 51
Step 2: Gathering Information 52
Needs Assessment: Gathering Information on the
Local Community 52
Problem Identification 56
Inventory 57
Step 3: Conceptualizing the Alternatives 58
Step 4: Making a Formal Decision 61
Step 5: Defining Measurable Objectives 61
Step 6: Implementing the Plan 62
Step 7: Evaluating the Results 63
Step 8: Repeating the Process 64
The End is Not the End 64
Continuous Data Gathering 64
Organizational Maintenance of Citizen Organizations 64
References 65
Appendix 3-A: A Model Lake Plan for a Local Community 67
CHAPTER 4
Problem Identification 101
Common Lake Problems 101
Algae 101
Aquatic Plants (Weeds) 103
Exotic Plants and Animals 103
Shallow Water Depth 104
Turbid Water 104
Toxins 104
Acidity 104
Salinity 105
Swimmer's Itch 105
Leeches 105
Fecal Coliforms, Pathogenic Bacteria, and Enteric Viruses 105
Undesirable Fishery 105
User Conflicts 106
Taste and Odor 106
Problem Identification 106
Causes of Lake Problems 106
Obtaining Professional Advice 107
Information Sources 108
Data Collection and Analysis 109
Sediment Cores 109
Water and Nutrient Budgets Ill
Precipitation Ill
Surface Water Ill
Groundwater 112
Monitoring Lake Water Quality 113
VI
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CONTENTS
Physical Variables 15
Estimating the Sedimentation Rate 15
Temperature 16
Transparency 17
Chemical Variables 18
Dissolved Oxygen 18
Nutrients 18
Metals and Organics 120
Acidification 120
Biological Variables 121
Bacteria and Pathogens 121
Algae 121
Macrophytes 122
Zooplankton 124
Animal Nuisances 124
Fish Community 126
Trophic State Indices 127
Using the Data to Manage Your Lake 129
Cedar Lake, Wisconsin 129
Mirror Lake, Wisconsin 131
References 136
CHAPTER 5
Predicting Lake Water Quality 139
Models 139
Eutrophication: The Problem 141
Modeling Eutrophication 142
Step I: Development of Hydrological and Nutrient Budgets 144
Step 2: Predicting Phosphorus Concentration 149
Step 3: Relationships Between Phosphorus and Other
Water Quality Variables 153
Step 4: Model Verification 156
Step 5: Forecasting and Tracking Changes in Water Quality 157
Modeling Other Pollutants 160
Nitrogen 160
Suspended Sediments 161
Acidity 162
Summary and Conclusions 162
References 162
CHAPTER 6
Watershed Management 165
Watershed Management: Principles, Processes, and Practices 165
Why Watersheds? 165
The Lake/Watershed Relationship—The Management Unit 166
Where Pollutants Come From 167
The Growing Trend for Watershed Planning and Management 168
Watershed Management Plans 168
Get Organized 169
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Managing Lakes and Reservoirs
Identify Problems and Opportunities 169
Develop Management Plan 169
Implement the Plan with Stakeholders 170
Monitor, Evaluate, and Adapt 170
TMDLs — A Watershed Management Tool 170
Background Sources 173
Point Sources 173
Nonpoint Sources 173
Total Maximum Daily Loads 173
From Planning to Practice 176
Watershed Management Practices: Point Sources 176
Wastewater Treatment 177
Municipal Systems 177
Small Community Systems 178
On-lot Septic Systems 180
Natural Treatments 183
Watershed Management Practices: Nonpoint Sources 183
What Are Best Management Practices? 185
Runoff and Erosion Control Practices 189
Nutrient and Contaminant Control Practices 191
Zoning and Ordinances 192
Water Conservation Practices 193
Integrated Watershed - and Lake — Management 193
References 195
Appendix 6-A: Best Nonpoint Source Resources 197
Agricultural BMP Manuals 197
Forestry BMP Manuals 201
Marina BMP Documents 204
Nonpoint Source Monitoring 206
Urban Nonpoint Source Documents 206
CHAPTER 7
Management Techniques Within the Lake or Reservoir. ... 215
Introduction 215
Principles of Management 215
In-lake Management: Matching Options to Problems 220
Management Options 229
Nuisance Algae 230
Nuisance Vascular Plants 258
Sediment Buildup 285
Non-algal Color and Turbidity 286
Anoxia and Related Issues 287
Acidification 287
Toxic Substances 289
Pathogens 289
Undesirable Fisheries 290
Animal Nuisances 293
User Conflicts 295
Cost of Lake Management 296
Comparing Costs 297
VIII
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CONTENTS
Permitting Lake Management 300
References 301
CHAPTER 8
Developing and Implementing a Management Plan 307
Why Plan? 307
What is a Management Plan? 308
The Planning Cycle 309
When Do You Start Planning? 309
Step I: Get Started 310
Step 2: Analyze the Situation 310
Step 3: Set Directions 311
Step 4: Evaluate Alternative Strategies and Actions 312
Step 5: Take Action 312
Step 6: Monitor and Evaluate Progress 312
Step 7: Do it Again 313
Sustaining the Management Effort 314
Build a Local Management Organization 314
Involve the Whole Lake Community 315
Consider Hiring a Professional Planner or Facilitator 316
Focus on the Whole Ecosystem 316
Developing the Management Plan 318
Getting Organized 318
Implementing the Work Plan 320
Implementing the Plan 328
The Management Organization 328
What Next? 333
References 333
CHAPTER 9
Lake Protection and Maintenance 335
Forming and Enhancing Lake Organizations 335
Lake Associations: Roles, Benefits, and Activities 335
Lake Districts 339
Where to Go for Help 341
Land-use Planning and Stewardship 342
Regulatory Approaches 342
Growth Management Tools 349
Voluntary Activities 352
Lake Monitoring 357
Establishing a Volunteer Monitoring Program 358
Putting It All Together 363
Lake Maintenance and Protection: An Ongoing Opportunity 365
References 365
Appendix 9-A: Example of Lake Association Bylaws 367
APPENDIX A: Glossary 371
APPENDIX B: Metric Units 381
IX
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Managing Lakes and Reservoirs
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Acknowledgments
Managing Lakes and Reservoirs is the third edition of a manual originally
titled The Lake and Reservoir Restoration Guidance Manual and produced
to provide guidance to citizens on lake and reservoir management The
first two editions were published in 1988 and 1990.
Managing Lakes and Reservoirs was prepared under the guidance of Chris
Holdren, Ph.D., project manager for the North American Lake Management Soci-
ety (NALMS), with the assistance of Bill Jones, also with NALMS, and Judy
Taggart of the Terrene Institute. Anne Weinberg has served as project manager
for the U.S. Environmental Protection Agency. The authors by chapter are:
CHAPTER 1: Overview of Manual
G. Chris Holdren, Ph.D., CLM, Bureau of Reclamation, Denver, Colorado
Judith F. Taggart, Terrene Institute, Alexandria, Virginia
CHAPTER 2: Ecological Concepts
William W. Jones, Indiana University, Bloomington
CHAPTER 3: Planning: From Goals to Evaluation and Around Again
Lowell Klessig, Ph.D., University of Wisconsin-Stevens Point
CHAPTER 4: Problem Identification
Paul Garrison, Wisconsin Department of Natural Resources, Madison
CHAPTER 5: Predicting Lake Water Quality
Gertrud NCirnberg, Ph.D., and Bruce D. LaZerte, Ph.D.
Freshwater Research, Baysville, Ontario, Canada
CHAPTER 6: Watershed Management
Kent W. Thornton, Ph.D., FTN Associates, Inc., Little Rock, Arkansas
Clayton Creager, Tetra Tech, Inc., Calistoga, California
CHAPTER 7: Management Techniques Within the Lake or Reservoir
Kenneth Wagner, Ph.D., CLM, ENSR, Inc., Wilbraham, Massachusetts
CHAPTER 8: Developing and Implementing a Management Plan
Dick Osgood, Ecosystem Strategies, Shorewood, Minnesota
CHAPTER 9: Lake Protection and Maintenance
Ann Baughman, Tip of the Mitt Watershed Council, Conway, Michigan
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Managing Lakes and Reservoirs
In addition to the authors, several other individuals made valuable contribu-
tions to this document. Extensive comments on the outline for this revision were
received from:
Frank X. Browne, Ph.D., P.E., F.X. Browne, Inc., Lansdale, Pennsylvania
Gertrud Nurnberg, Ph.D., Freshwater Research, Baysville, Ontario, Canada
Kent W.Thornton, Ph.D., FTN Associates, Inc., Little Rock, Arkansas
Anne Weinberg, U.S. Environmental Protection Agency, Washington, D.C.
Once the initial outline was developed, the following individuals provided
written suggestions for improving the manual that were forwarded to chapter au-
thors for consideration:
Chauncey Anderson, USGS-WRD, Portland, Oregon
Terry Anderson, Kentucky Division of Water, Frankfort
Roger Bachman, Ph.D., University of Florida, Gainesville
Bud Cann, New Jersey Department of Environmental Protection, Trenton
Timothy D. Feather, Ph.D., Planning and Management Consultants, Ltd.,
Carbondale, Illinois
Eileen Jokinen, University of Connecticut, Storrs
Shannon Lotthammer, Minnesota Pollution Control Agency, St. Paul
Gerd Marmulla, FAO/FIRJ, Rome, Italy
Jenifer Parsons, Washington State Department of Ecology, Olympia
The original Chapter 2, written by Bruce Kimmel in Lake and Reservoir Resto-
ration Manual (1988), served as the foundation for Chapter 2 in this manual.
Other chapters also built on the work of the two previous editions, and acknowl-
edge the contributions of those authors: Frank X. Browne, G. Dennis Cooke, Wil-
liam H. Funk, Douglas Knauer, Harvey Olem, Forrest E. Payne, William W. Walker,
and Richard Wedepohl.
The following limnologists and lake management professionals reviewed
Chapter 7 (In-lake Management Techniques section):
G.Dennis Cooke, Ph.D., Kent State University, Kent, Ohio
Tom Eberhardt, Sweetwater Technology, Brainerd, Minnesota
Richard Geney, General Environmental Systems, Summerfield, North Carolina
Robert Kortmann, Ph.D., Ecosystem Consulting Services, Coventry, Connecticut
Gerald Smith, Aquatic Control Technology, Sutton, Massachusetts
Eugene B.Welch, Ph.D., University of Washington, Seattle
Once a draft of the document was prepared, the entire document was evalu-
ated through a formal peer review process to ensure that it would be acceptable
to the target audience and that the information in the document was accurate.
The document was reviewed by the following individuals, as well as several re-
viewers from U.S. EPA:
John Mains, Ph.D., U.S. Army Corps of Engineers Waterways Experiment
Station, Calhoun Falls, South Carolina
Jeff Schloss, Cooperative Extension, University of New Hampshire, Durham
Al Sosiak, Alberta Environment, Calgary, Canada
Barbara Speziale, Ph.D., Clemson University, South Carolina
Steven Weber, Lake Las Vegas Resort, Henderson, Nevada
XII
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Donald D. Moores, Clearwater, Florida, and Lura Svestka, Terrene Institute,
Alexandria, Virginia, developed the glossary for the document.
Once all suggested changes had been incorporated, the document went
through a final review by the editors, chapter authors, and U.S. EPA. Nancy Page,
Pinellas County Mosquito Control, Clearwater, Florida, also read the document
to provide an additional check for clarity and grammatical errors.
Additional assistance throughout the process was provided by Philip
Forsberg, North American Lake Management Society, Madison, Wisconsin, who
assisted with project management and who helped solicit comments on the out-
line through the NALMS web site, and by Carlene Bahler, Terrene Institute, Alex-
andria, Virginia.
Lura Svestka of the Terrene Institute designed and typeset this manual and
served as Production Manager for its publication.
All of these individuals are gratefully acknowledged for their efforts and con-
tributions. The authors are particularly commended for their tireless work and
their patience with the numerous reviews and revisions that led to the finished
document.
••*
XIII
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Managing Lakes and Reservoirs
XIV
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CHAPTER 1
Overview
This manual deals with the very broad subject of protecting and managing
lakes and reservoirs. It marks a complete revision of the first two editions of
the Lake and Reservoir Restoration Guidance Manual (1988 and 1990). An enor-
mous amount of information on lake management has been developed in the dec-
ade since their publication. So much information, in fact, that the burden on the
authors of this third edition was not in finding good material to include, but in de-
ciding where to stop.
The authors faced two additional substantive challenges:
I. To create a manual that deserves premier shelf space for its reference
value, but remains compact enough to be eminently useful to the
reader; and
2. To communicate that the term "management" is now more accurate
than "restoration," largely because we don't always know the original
conditions of natural lakes, and some reservoirs experience water
quality problems from the moment they are impounded.
The North American Lake Management Society (NALMS) joined with the
Terrene Institute and the U.S. Environmental Protection Agency to respond to
these challenges and produce Managing Lakes and Reservoirs.
Who Should Use This Manual?
Although scientists and engineers will probably find this manual useful, it is writ-
ten for informed citizens who are interested in protecting and managing lakes.
Consequently:
• Technical jargon is kept to a minimum to help you grasp important
points without stumbling over the words.
• Terms that are essential to lake management are defined in a sidebar
the first time they appear, clearly explained in the text, and included in
the glossary (Appendix A).
• The relatively simple word, lake, is used generically throughout this
manual to include both natural and constructed lakes, which are called
reservoirs. Distinctions between the two types of systems are
discussed when they have important management implications.
Lake: a considerable inland
body of standing water.
Reservoir: a lake created
by artificially damming a
stream or river.
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Managing Lakes and Reservoirs
Eutrophicalion: the process
of physical, chemical, and
biological changes in a lake
or reservoir associated with
nutrient, organic matter, and
silt enrichment. If the process
is accelerated by human
influence, it is called cultural
eutrophication.
2
• English units of measure are used, except for a few terms that are
almost always reported in metric units (see Appendix B for
information on the metric system).
• References to scientific literature and other sources of information
are listed to provide more details.
The material presented in this manual fulfils a fourfold purpose:
I. To help you identify, describe, and define your lake problems;
2. To help you evaluate available lake and watershed management practices
for addressing specific problems or for protecting water quality;
3. To describe the process of developing a site-specific lake or reservoir
management plan; and
4. To illustrate how to put a lake management plan into practice and
evaluate its effectiveness.
How the Manual is Organized
Each chapter is self-contained. You should be able to go directly to a chapter
you're particularly interested in and find both adequate background information
to understand the material discussed and guidance on how to apply the tech-
niques described. While this does result in some repetition, it also provides you
with more than one approach for managing your lake.
Information in this manual is arranged in much the same order you would
follow in undertaking a lake management project. Topics fall into three general
parts:
• Part I. Understanding and Defining the Problem;
• Part 2. Lake and Watershed Management Techniques; and
• Part 3. Developing, Implementing, and Evaluating a Management Plan.
Part I — Understanding and
Defining the Problem
T Chapter 2, Ecological Concepts, describes how inseparably lakes
and watersheds are coupled and how lakes function as ecosystems. You must
have some understanding of how the various components of a lake and water-
shed work and fit together before you can manage your lake. In other words, you
don't have to be a mechanic to drive a car, but you do need to understand what
makes the car go and what makes it stop. The eutrophication process, for exam-
ple, can be accelerated or slowed down by various management techniques.
Chapter 2 describes key lake and watershed processes, eutrophication and
other ecological concepts, and explains the importance of understanding ecologi-
cal processes before undertaking a lake restoration project.
T Chapter 3, Planning: From Goals to Evaluation and Around
Again, describes the importance of planning in the management process. The
chapter deals with such key items as clarifying goals, developing alternatives, defin-
ing measurable objectives, and implementing and evaluating the management plan.
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CHAPTER I: Overview
The planning process is a critical part of lake management that is often over-
looked.
T Chapter 4, Problem Identification, discusses common lake prob-
lems, data collection and analysis techniques, typical water quality variables and
monitoring techniques for assessing them, and how to use monitoring data to
evaluate the effectiveness of lake and watershed management techniques.
T Chapter 5, Predicting Lake Water Quality, discusses modeling
techniques for evaluating lake water quality and the effects of management tech-
niques. While many users believe modeling takes place only after all data have
been collected and a management plan implemented, this should not be the case.
If modeling is to be used effectively, the data required by the model to evaluate
the success of a management plan must be collected during the monitoring phase
of the project. Chapter 5 focuses on modeling phosphorus concentrations in
lakes, primarily because phosphorus is most often the nutrient involved in the
eutrophication process, but also because phosphorus models are more highly de-
veloped than models for other water quality variables.
Part 2 — Management Techniques
T Chapter 6, Watershed Management, completely revised for this
edition of the manual, recognizes that watersheds are critical in determining lake
water quality. Point and nonpoint sources of pollutants are identified and dis-
cussed. In addition, best management practices for watershed management are
described. Complete descriptions of various watershed management practices
appear in Appendix 6-A.
Chapter 6 also discusses the Clean Water Act's Total Maximum Daily Load
(TMDL) process that deals with pollutant loads to water bodies. Many states are
using information developed for lake diagnostic studies to develop TMDLs.
T Chapter 7, Management Techniques Within the Lake or
Reservoir, discusses in-lake management techniques for achieving a desired
lake use. Information on advantages, disadvantages, mode of action, and approxi-
mate costs are given for the techniques presented. Tables help you find tech-
niques particularly relevant to your problems, and numerous references guide you
to additional sources of information.
Part 3 — Developing, Implementing, and
Evaluating a Lake Management Plan
T Chapter 8, Developing and Implementing a Management
Plan, describes how to develop a specific lake management plan and put it into
practice. Chapter 8 differs from Chapter 3 in that Chapter 3 focuses on the steps
necessary to develop consensus and set management goals, while Chapter 8 goes
into more detail on the numerous practical details that are an important part of in-
tegrating lake and watershed information into an effective lake management plan.
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Managing Lakes and Reservoirs
any lakes would
be eutrophic even
Jwithout human activity.
T Chapter 9, Lake Protection and Maintenance, discusses how to
protect lake quality, either as it exists or after the management plan is in place. You
will learn how to form a lake association, conduct lake protection and stewardship
activities, and develop a lake monitoring program. Chapter 9 emphasizes the fact
that lake management is ongoing, not a short-term endeavor.
Appendices
Appendices supplement the material covered in Chapters I through 9, both at the
end of the chapters themselves and at the conclusion of the manual. The glossary
(Appendix A) contains definitions of many common lake management terms. Addi-
tional definitions can be found in the glossary maintained at the NALMS web site
(www.nalms.org/glossary/glossary.htm). Appendix B shows how to convert English
units to metric units, which are more common units of measure in lake manage-
ment.
Focus of the Manual: Wafer Qualify
This manual focuses on lake water quality. Particular attention is paid to the ef-
fects of excessive inputs of silt, nutrients, and organic matter — a process known
as eutrophication.
The natural geologic process for moderately deep lakes is to gradually fill
and become wetlands. The position of a lake along this geologic continuum from
deep to shallow influences its natural water quality. Reservoirs are affected by
similar problems. And because they're typically constructed along stream channels
that naturally erode, reservoirs begin to fill with silt from the moment they are
impounded and usually have much shorter life spans than natural lakes of similar
size (see Chapter 2).
So the natural condition of a lake — before home construction, before
deforestation, before agriculture and other human activities — may not have been
nearly as pristine as has been commonly believed. Many lakes would be eutrophic
even without human activity.
• In the Southeast, for example, soil fertility, runoff patterns, and geology
encourage a somewhat more eutrophic natural condition compared to
northern lakes. Northerners expecting to see deep blue waters may
be dismayed by the color of healthy southern lakes.
• Even comparing neighboring lakes may be misleading because they may
differ in critical ways — depth, water source, erodibility of watershed
soils, comparative watershed size, and local land use — whether
they're across town from each other or across the state. For example,
changes in lake quality from northern to southern Wisconsin or from
eastern to western Minnesota reflect regional differences in soils and
underlying geology.
Regional differences in climate, rainfall, topography (hills, valleys, plains),
soils, geology, and land use all influence lake water quality. These factors have been
studied and used to define areas with similar characteristics called ecoregions
(Omernik, 1987). Each ecoregion has natural landscape features that can influence
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CHAPTER 1: Overview
lake quality. Thus, to effectively manage your lake, you must identify the uses sup-
ported by these natural factors and develop a plan that will either restore the
lake to this natural condition or protect its current condition.
Making Your Lake Work for You
This manual concentrates on how to determine what uses a reasonably managed
lake can support. It is critical, therefore, to decide the way your lake will be used
and to have those goals clearly in mind as you delineate existing lake and water-
shed problems.
Lake usage is a match between people's desires and the lake's capacity to sat-
isfy them. Lake problems are defined in terms of the limits on desired uses —
limitations that can be prevented or corrected with proper management. This is a
critical definition for developing lake management programs: A lake problem is a
limitation on the desired uses by a particular set of users. Before undertaking a
management program, you must clearly define these desired uses, identify the
limitations, and understand what causes them.
A lake cannot be all things to all people. Desirable uses, even obtainable ones,
can conflict. Lake organizations invariably would like to see their lake do every-
thing. They want aesthetic pleasure, great fishing, clean water, sandy shorelines
and bottoms, and a healthy wildlife population — all without pests, insects, or
weeds. Unfortunately, almost no lake can meet all of these demands.
Individual lakes are suited to particular uses depending on physical charac-
teristics of the lake basin and watershed and the quality of incoming water. Even
when a lake can be used in several ways, it still may be necessary to manage for a
specific use. Like cattlemen and sheepherders, motorboaters and trout fishermen
don't necessarily get along.
Although it might be technically possible to drastically change a lake to meet
the needs of a particular use, the cost will be high and the lake will usually require
extensive maintenance; thus, the decision is usually unwise. You must understand
a lake's capacity and attainable quality when developing a management plan. For
example:
• Some lakes will never remain crystal clear, regardless of what you do, or
• If the drainage area is large relative to the lake surface and the soils in
the watershed are highly erodible and nutrient-rich, the lake will
quickly revert to a turbid state without constant management
attention.
Defining — and Attaining —
Desired Uses
While users obviously should decide how their lake should be used, they often
lack sufficient knowledge to assess whether a use is practical. This manual will
help you examine the feasibility of proposed lake management goals. Chapter 3
focuses on the planning process, including setting management goals and deter-
mining their feasibility.
For many problems, you may need to consult an expert. If so, carefully exam-
ine the qualifications of groups or individuals being considered to determine who
ike usage is a match
between people's desires)
and the lake's capacity
to satisfy them. ;
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Managing Lakes and Reservoirs
I
,ake and reseivoir
nanagement is an
active process. Informed
citizens must become
nvolved if you are to
achieve desired and
attainable lake uses for
four lake.
can best address the problem. State and federal agencies or universities may be
able to furnish general lists of experts dealing with lake management issues, but
references from groups with similar problems are usually more beneficial. In ad-
dition, NALMS maintains a list of Certified Lake Managers on its web site
(www.nalms.org/member/nalmsclm.htm). The CLM program identifies individuals
recognized by NALMS as having exceptional training and experience in lake man-
agement.
Lake and reservoir management is an active process. Informed citizens must
become involved if you are to achieve desired and attainable lake uses for your
lake. Getting people together and simply finding out what they want may require
as much effort as figuring out how to do it. Since a given lake may serve many dif-
ferent groups of users, several methods might be required to involve them all.
Lake homeowners and other local users can get involved with lake use deci-
sions by belonging to one of several types of lake organizations. The legal and finan-
cial ability of these groups varies considerably from community to community and
state to state (see Chapter 9 for additional discussion of legal authority and issues).
The annual meeting of the local lake group is an obvious place to discuss and vote
on priority uses for the lake. If the lake serves primarily local property owners and
residents, such votes are likely to be respected by government agencies. Although
large popular lakes are often managed by government agencies rather than by
homeowners and lake associations, you can still provide information for managing
these lakes by contacting the appropriate agencies.
Reaching a consensus on specific lake uses may be difficult, however, if more
than one lake organization exists on the lake, especially if conflicting uses are al-
ready well established. Several procedures can be used to reach a consensus on
desired lake uses and to identify various lake problems. These approaches, de-
scribed in more detail in Chapter 3, include surveys, the nominal group process,
and the Delphi process.
While consensus-building techniques can be very effective when properly
used, most lake managers and informed citizens will need professional assistance.
Lake associations typically include people of diverse occupations, however, so a
member of the association may have the experience needed to use these methods.
Based on the fact that a lake problem is a limitation on the desired uses by a
particular set of users, a definition of desired lake uses and the limitations on
these uses represents the cornerstone of any lake management program.
Causes v. Symptoms: A Major
Reason for this Manual
Lake users often tend to confuse the symptoms of problems with their causes.
Although you will probably need professional help to identify causes of lake prob-
lems, you must understand lakes in general. The purpose of this manual is to help
you define problems, understand underlying causes, evaluate techniques for ad-
dressing problems, develop an effective lake management plan, implement this
plan, and evaluate its effectiveness.
In most cases, managing or restoring a lake eventually requires help from a
professional lake manager, limnologist, or experienced professional. This manual
will help you find and select qualified consultants.
-------
CHAPTER J: Overview
This manual provides general guidance on lake and reservoir restoration and
management techniques that have been proven on lakes throughout the United
States and Europe. Some techniques might have to be modified for your particu-
lar lake in a specific region. This variability brings up a key point in lake manage-
ment: whatever the starting conditions and the limitations on what can ultimately
be achieved, the goal is always the same — managing the lake to minimize lake
water quality problems.
Funding for Lake Management
Projects
Two approaches can be used for financing lake management projects:
I. Determine the amount of funding available from various sources and
then develop the best possible project that can be completed within the
specified budget; or
2. Develop the management project and then raise money through any
means available to fund it.
Neither approach is best for all circumstances. Which of these two ap-
proaches is used depends on numerous factors, including the availability of exter-
nal funding, the extent of the problems identified, and the abilities and interests of
the individuals and organizations involved in the management effort.
Although Chapters 8 and 9 suggest ways to fund lake management projects,
this is not a major focus of the manual. There are several reasons for this omis-
sion:
• There is no single source of funding that can be used in all cases.
• Different groups often have widely varying ideas of how much funding
is needed to implement a management program.
« Funding opportunities often change and any specific information
provided here would quickly become out of date.
It is often possible to obtain state or federal funding to implement a lake man-
agement project, particularly for lakes with public access. Contact your state envi-
ronmental agency to find out if any programs exist in your area and, if so, what
requirements (local match, public access, state priority lists, etc.) must be met.
Local fundraising efforts can also be very effective. Many lake associations
have been able to raise hundreds of thousands of dollars for lake management
projects without any state or federal assistance. The amount of money raised
through local efforts is limited only by the ingenuity of those involved.
Sources of Additional Information
Previous editions of this manual included extensive lists of federal agencies and
state sources of information that could be used for assistance with lake manage-
ment projects. Such lists quickly become outdated through personnel changes
and even changes in the names of the agencies involved. The U.S. Environmental
Protection Agency, local offices of the U.S. Department of Agriculture Natural
Resources Conservation Service, and state environmental agencies remain good
-------
Managing Lakes and Reservoirs
starting points for information. Some good technical (Cooke, et al. 1992) and
popular (McComas, 1993; Phillips et al. 2000) books on lake management also are
excellent sources. Additional sources of information are described in Chapter 9.
The growth of the internet has replaced many traditional means of finding in-
formation. For individuals without personal computers, most local libraries now of-
fer computers and assistance with internet access. Search engines, such as Yahoo or
AltaVista, can be used as a starting point for obtaining information on specific top-
ics, while home pages for many organizations involved with lakes offer links to
other information sources. Examples include the home page of the EPA Office of
Wetlands, Oceans, and Watersheds (www.epa.gov/owow), which has links to many
sources of information; the resources section on the NALMS home page
(www.nalm.org/resource/resource.htm); and the links page on the Terrene home
page (www.terrene.org).
Lakes as Resources
Lakes are important natural resources. As sources of recreation, they support
fishing, boating, swimming, and aesthetic enjoyment. Fishing and swimming are
among the fastest growing and most popular forms of outdoor recreation in the
United States and Canada. Lakes' commercial value in food supply, tourism, and
transportation is worth many billions of dollars each year.
Lakes also provide life-sustaining functions such as flood protection, genera-
tion of electricity, and sources of drinking water.
And, as places of beauty, they offer solitude and relaxation: for example, over
60 percent of Wisconsin lake property owners asked what they valued in lakes
rated aesthetics as especially important.
Yes, you value your lake. We understand that, and offer you this manual as a
tool that will empower you to protect and manage your precious resource.
References
Cooke,G.D..E.Welch,S.Peterson,and P.Newroth. 1993.Restoration and Management
of Lakes and Reservoirs. 2" ed. Lewis Publishers, Boca Raton, FL.
McComas, S. 1993. Lake Smarts: The First Lake Maintenance Handbook. Terrene
Institute, Alexandria, VA.
Moore, L. and K. Thornton, eds. 1988. Lake and Reservoir Restoration Guidance
Manual. EPA 440/5-88-002. Prep, by N. Am. Lake Manage. Soc. for Office of Res.
and Devel., Envir. Res. Lab., Corvallis, OR, and Office of Water, Criteria Stand.
Div., Nonpoint Sources Branch, U.S. Environ. Prot. Agency, Washington, DC.
Olem, H. and G. Flock, eds. 1990. Lake and Reservoir Restoration Guidance Manual,
2nd ed. EPA 440/4-90-006. Prep, by N. Am. Lake Manage. Soc. for U.S. Environ.
Prot. Agency, Washington, DC.
OmernikJ.M. 1987. Aquatic ecoregions of the conterminous United States. Ann. Ass.
Am. Geogr.
Phillips, N., M. Kelly, and J. Taggart. 2000. The Lake Pocket Book. Terrene Institute,
Alexandria, VA.
8
-------
CHAPTER 2
Ecological Concepts
Lake and Reservoir Ecosystems
The condition of a lake at any one particular time is the result of a complex inter-
action of many different physical, chemical, and biological factors. Rainfall cycles,
watershed characteristics, lake basin shape and depth, the lake water itself, and
bottom sediments all contribute to this condition. These physical and chemical
factors, in turn, support a community of biological organisms that is unique to
lakes (Fig. 2-1). In fact, the plants and animals, along with the physical and chemical
components of their immediate environment, define the lake ecosystem.
We can gain an understanding of aquatic ecosystems through limnology: the
study of the physical, chemical, geological, and biological factors that affect aquatic
productivity and water quality in freshwater ecosystems —lakes, reservoirs,
rivers, and streams.
Understanding these fundamental ecosystem processes is critical if we are
to effectively manage a lake. Lakes are highly interactive systems. It is impossible
to alter one characteristic — for example, the amount of rooted plants or algae
— without affecting some other part of the system, such as fish production.
The components of lake ecosystems are constantly changing. Light increases
and decreases, plants grow and die, nutrients are used and released, eggs hatch,
insects emerge, the water circulates — in regular or irregular, long or short cy-
cles. Recognizing the natural changes in your lake not only helps you better un-
derstand lake ecology but also gives you reasonable expectations for lake
management outcomes.
For example, a lake association on an otherwise high-quality lake might
overreact to a late summer algal bloom by treating the algae chemically, causing a
massive algal die-off that can consume vital oxygen and disrupt food chains. Had
they understood how the lake works, they would have known that many lakes
experience a late summer increase in algae but the algae will die shortly, as days
grow shorter and water temperatures drop below the optima for algae — so the
condition will clear up on its own. The chemical treatment in this case was a
waste of effort and money, added unnecessary chemicals to the lake, and treated
a symptom (algae growth) rather than the cause (nutrients).
This chapter is not intended to be a complete text on limnology. Rather, it
will give you the background information to understand lake processes, interpret
lake data, and understand the causes of lake degradation — to prepare you to
make sound lake management decisions.
Ecosystem: A system of
interrelated organisms and
their physical-chemical
environment. In this manual,
the ecosystem is usually
defined to include the lake
and its watershed.
Biota: All living organisms
(e.g., plants, animals, fungi,
bacteria) occurring in a
specified area.
Ecology: Scientific study of
relationships between
organisms and their
environment. Also defined as
the study of the structure and
function of nature.
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Managing Lakes and Reservoirs
Marginal zone
Littoral zone
Littoralf)
1 -*" •*•
Pelagic zone
Profundal zone
Pelagic zone (open water)
Benthic zone
Figure 2-1.—The location and nature of typical lake communities, habitats, and organ-
isms. In addition to the lake's -watershed, all of these components are part of the lake
ecosystem. Source: Moore and Thornton, 1988.
10
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CHAPTER 2: Ecological Concepts
Lake Formation and Distribution
The physical characteristics of lakes — such as shape, area, depth, and watershed
size — are largely established when the lake forms. In his classic work, A Treatise
on Limnology (1957), G.E. Hutchinson described 76 different ways in which lakes
form. These can be condensed into a few basic types of lakes.
V Glacial Lakes* Most of the natural lakes in the Upper Great Lakes
Region were created during the last period of glaciation some 14,000
years ago. As the massive ice sheets advanced and then retreated back to
the north, they left several different types of lakes:
• Depressions scoured by the glacier filled with meltwater: ice
scour lakes (the Great Lakes are a good example);
• Rock and soil debris (terminal and lateral moraines) deposited by
the receding glacier dammed up valleys creating lakes (for
example, New York's Finger Lakes); and
• Large blocks of ice left behind formed and filled in depressions,
creating ice-block or kettle lakes (Fig. 2-2).
'
Limnology is the scientific
study of the physical,
chemical, geological, and
biological factors that affect
aquatic productivity and
water quality in freshwater
ecosystems—lakes, reservoirs
rivers, and streams.
DURING GLACIATION
About 3,000 years ago the last glaciers began
to retreat from the North American continent.
Many of the small lakes in the upper midwest
and north central states as well as Canada
were formed by huge ice blocks buried in the
loose rock and soil and deposited by the
glaciers. When the buried ice blocks melted,
they left holes in the glacial till which filled with
water from the melting glaciers.
GLACIAL TILL
.•MORAINE
CHAIN OF LAKES
OUTWASH
PLAIN
RIVERA
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Managing Lakes and Reservoirs
Caldera lake: a large,
usually deep basin that forms
in the center of an inactive
volcano.
^ Volcanic* Volcanic activity creates lakes when water fills an inactive
caldera (large crater) (Crater Lake, Oregon) or when lava flows dam up
valleys (lakes within Lassen National Park, California).
V Reservoirs. Much of the central and southern United States has been
relatively untouched by recent glaciation, landslides, and volcanoes. In
these areas people create lakes, more correctly called reservoirs or im-
poundments. Federal agencies have impounded major rivers and operate
the resulting large reservoirs for multiple purposes: water supply, flood
control, recreation, wildlife, and hydroelectric power generation.
^ Other Types, Other lakes have been formed by earthquakes, landslides,
and dissolution of soluble rock formations (solution lakes). Solution lakes
are most common in the karst regions of Indiana, Kentucky, and Florida.
Just how many lakes are there in the United States anyway? Most reliable es-
timates have set the figure at 100,000 lakes larger than 100 surface acres — ex-
cluding Alaska, which has several million alone (Horwitz, 1980).
The Lake and Its Watershed
A lake is not an isolated body of water, but part of a larger ecosystem that in-
cludes the surrounding land that drains into the lake. The land from which rain
and surface water drain toward a central collector such as a stream, river, or lake
is called a watershed, catchment, or drainage basin (Fig. 2-3).
Watershed: A drainage
area or basin in which land
and water areas drain or flow
toward a central collector
such as a stream, river, or
lake at a lower elevation.
,
> J
Figure 2-3.—A lake's watershed includes all wetlands, streams, and upland areas from
which water flows into the lake (dark arrows). Source: Horwitz (1980) Our Nation's
Lakes, pg. I 7.
12
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CHAPTER 2: Ecological Concepts
Watershed Inputs
It is often said that a lake is a reflection of its watershed. This is most certainly
true. Lakes receive water, dissolved materials carried in water, and participates,
such as soil, from their watersheds; particulates and gases from the atmosphere;
and energy from the sun and wind. Therefore, the condition of a lake at any one
time is determined not only by what is already in the lake, but also by these out-
side factors — further confirming lakes as complex ecosystems.
^ Water. In a continuous cycle, rain or snow falls on the land; fills rivers,
streams, and lakes; evaporates and returns to the atmosphere to eventu-
ally fall on the land again (see Fig. 2-4). The volume of water entering lakes
can have important consequences for lake processes and management.
Direct precipitation, surface water runoff, and groundwater flow all
contribute to keeping lakes filled with water. Like a bathtub, when the en-
tering water exceeds the capacity of the lake, it overflows. In most lakes,
the overflow leaves via a surface outlet stream. The relationship between
the volume of a lake and the volume of water entering the lake over time
determines the lake's hydraulic (water) residence time (see Fig. 2-5).
If the water entering the lake from all sources during the year equals
the volume of the lake, the hydraulic residence time is one year. Lake
Shafer, a shallow Indiana reservoir with a very large watershed, has a hy-
draulic residence time of only three days. Lake Tahoe, California, a deep
lake with a relatively small watershed, has a hydraulic residence time of ap-
proximately 700 years!
^ Particulates. Soil, leaves, twigs, and other organic debris are particu-
lates (also known as TSS: total suspended solids) carried into lakes by
water running off the watershed. Human activities that disturb the natu-
ral, vegetated land cover promote these losses (Table 2-1).
Particulates may surge following major storms as high velocity water
erodes stream beds and banks. Other particulates fall into lakes from the
atmosphere — wind-blown soil from newly-tilled agricultural fields being a
major source.
Particulates add to the turbidity of lake water, thus decreasing water
transparency and the light algae need to grow — conversely, nutrients at-
tached to particulates can promote excessive algal growth.
Fish are also affected by particulates. Some find it difficult to locate
prey in muddy waters, reducing their growth rates and overall health. Fine
particulates irritate the gills of some fish species. And particulate deposits
often cover fish spawning sites and smother their eggs. Particulate deposits
also damage habitat for aquatic insects, which are a major food source for
some fish.
Lakes trap sediments very efficiently. Flowing stream water keeps
particulates suspended, but when it empties into a lake, the flow diminishes
and the particulates eventually settle onto the lake bottom. This accumula-
tion decreases lake volume, creates shallow water areas where rooted
plants can grow, and may interfere with boats.
Motorboats may actually resuspend newly-deposited fine particulates,
further decreasing transparency. For example, a 75-hp boat motor can re-
suspend fine clay sediments to a depth of over 10 feet (Yousef et al. 1978).
Organic matter: Molecules
manufactured by plants and
animals containing linked
carbon atoms and elements
such as hydrogen, oxygen,
nitrogen, sulfur, and
phosphorus.
13
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Managing Lakes and Reservoirs
The Hydrologic Cycle
Because precipitation and surface water runoff directly influence the nature of lake
ecosystems, a good way to begin to learn about lakes is to understand the
hydrologic (water) cycle. The circulation of water from atmosphere to Earth and back
to the atmosphere is a process that is powered by the sun. About three-fourths of the
precipitation that falls on land is returned to the atmosphere as vapor through evapo-
ration and transpiration from terrestrial plants and emergent and floating aquatic
plants. The remaining precipitation either is stored in ice caps, or drains directly off
the land into surface water systems (such as streams, rivers, lakes, or oceans) from
which it eventually evaporates, or infiltrates the soil and underlying rock layers and
enters the groundwater system. Groundwater enters lakes and streams through under-
water seeps, springs, or surface channels and then evaporates into the atmosphere.
SEER
INFILTRATION
GROUND WATER
WATER TABLE
BEDROCK
Figure 2-4.—The hydrologic cycle. Source: Moore and Thornton, 1988.
Lakes and reservoirs have a water "balance," as described in this simple equa-
tion: water input = water output +/- the amount of water stored in the lake. Inputs are
direct precipitation, groundwater, and surface stream inflow, while outputs are sur-
face discharge (outflow), evaporation, losses to groundwater, and water withdrawn
for domestic, agricultural, and industrial purposes. If inputs are greater than outputs,
lake levels rise as water is stored. Conversely, when outputs are greater — for exam-
ple, during a summer drought —lake levels fall as losses exceed gains.
Some lakes, called seepage lakes, form where the groundwater flow system in-
tersects with the land surface. Seepage lakes are maintained primarily by groundwa-
ter inflow, and their water levels fluctuate with seasonal variations in the local water
table. Drainage lakes, on the other hand, are fed primarily by inflowing rivers and
streams; therefore, their water levels vary with the surface water runoff from their wa-
tersheds. In both cases, the balance between hydrologic inputs and outputs influences
the nutrient supply to the lake, the lake's water residence time, and, consequently, the
lake's productivity and water quality. *
14
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CHAPTER 2: Ecological Concepts
Hydraulic Residence Time
The average time required to completely renew a lake's water volume is called
the hydraulic residence time. For instance, it might take 5 minutes to completely
fill a bathtub with the tap fully open and the bottom drain closed. The hydraulic res-
idence time of the tub, then, is 5 minutes. With the tap and drain only half open,
the hydraulic residence time would be 10 minutes.
(a)
Inflow =
10 gal/min
Outflow =
10 gal/min
Hydraulic residence time = Volume * Flow Rate
= 50 gal +. 10 gal/min = 5 min
(b) Inflow =
10 acre-ft/day
Outflow =
10 aofe-ft/day
Water residence time = 500 acre-ft •*• 10 acre-ft/day = 50 days
Figure 2-5.—Hydraulic residence time is an important factor to consider in
restoration programs. The simple formula given in the figure assumes that
inflow is equal to outflow. Source: Moore and Thornton, 1988.
If the lake basin volume is relatively small and the flow of water is relatively
high, the hydraulic residence time can be so short (10 days or less) that algal cells
produced in the water column are washed out faster than they can grow and accu-
mulate.
An intermediate water residence time allows both an abundant supply of plant
nutrients and adequate time for algae to assimilate them, to grow, and then accu-
mulate.
Longer water residence times from 100 days to several years provide plenty of
time for algal biomass to accumulate if sufficient nutrients are present. The produc-
tion of algae may ultimately be limited by the supply of nutrients. If the nutrient sup-
ply is high, algal biomass will be very large. The combined effects of nutrient
income (or "nutrient loading") and hydraulic residence time on the production of al-
gae is the basis of methods for predicting changes in the lake's condition following
variations in one or both of these processes (such as the diversion of wastewater
flows). These concepts are discussed in more detail in Chapter 5. *
Algae: generally
microscopic plants found
suspended in lakes (phyto-
plankton) or attached to solid
structures (periphyton).
Acre-foot: volume measure
equal to 1 foot of water
covering 1 acre of area;
1 ac-ft = 382,850 gallons.
15
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Managing Lakes and Reservoirs
Buffering capacity:
the ability of lake water to
resist changes in pH or
acidity. The buffering
capacity comes from alkaline
materials (for example,
carbonates, bicarbonates,
sulfales) that neutralize acids.
,
' Dissolved Material, Surface runoff and groundwater discharges
carry a variety of dissolved materials to the lake, among them:
• Minerals dissolved from bedrock deposits, such as calcium
carbonate (an important component of a lake's buffering
capacity);
• Metals derived from bedrock (e.g., iron and aluminum) or human
activities (e.g., zinc and lead) that are important to many chemical
and biological functions within lakes;
• Pesticides, herbicides, toxic pollutants, chemicals in wastewater
discharges, and industrial waste materials;
• Phosphorus and nitrogen, the primary plant nutrients that
encourage growth of algae and rooted plants; and
• Oxygen, needed by fish and other aquatic organisms, and
important in many chemical reactions in lakes.
Phosphorus and nitrogen are two of the more important dissolved
materials in most runoff. While phosphorus and nitrogen occur naturally
in leaf litter, soil, and bedrock, they are readily lost in runoff when people
disturb the land, primarily by growing row crops or building structures
(Table 2-1).
Table 2-1.— Example ranges and median values for sediment and nutrient
export and input rates for various land uses. All values are in kg/ha-yr
(kilograms lost from 1 hectare of land per year).
LAND USE
SUSPENDED
SOLIDS
TOTAL
PHOSPHORUS
TOTAL
NITROGEN
RURAL EXPORT
Cropland
Improved pasture
Forest/Woodland
Feedlot
20-5,100
30- 80
1 - 820
—
0.2 - 4.6
0.1 - 0.5
0.02 - 0.67
10-620
4.3 -31
3.2 - 14
2.0 - 20
1 00 - 1 ,600
URBAN EXPORT
Residential
Commercial
Industrial
Developing urban
620 - 2,300
50 - 830
450- 1,700
27,500
0.4- 1.3
0.1 - 0.9
0.9-4.1
23
5.0 - 7.3
1.9-11
1.9-14
63
ATMOSPHERIC INPUT
Forest
Agricultural
Urban industrial
—
—
—
0.26
0.28
1.01
6.5
13.1
21.4
Sources: Novotny and Olem, 1 994; Reckhow ef al. 1 980; Sonzogni et al. 1 980.
16
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CHAPTER 2: Ecological Concepts
Airsheds
A lake's airshed is often overlooked as an important contributor to its water quality.
The airshed represents the area of the atmosphere from which airborne materials
are transported and deposited on a lake and its watershed. Generally larger than its
watershed, an airshed's size depends on the direction and speed of the wind that car-
ries gases and particulates.
Among the airborne contaminants affecting lakes is phosphorus. Winds pick up
and carry large amounts of dust and soil from agricultural fields and urban areas.
Phosphorus attached to these particles can be transported many miles and eventually
deposited in lakes as dry particulates or mixed with rain. In rural northeastern Connect-
icut the annual atmospheric deposition of phosphorus on the land was measured at
126 mg/m (Kortmann, 1991). This alone can contribute a significant amount of phos-
phorus to shallow lakes and ponds.
Airsheds are Important Too!
Isle Royale
Adirondack Mts
Many other lake pollutants are carried in the air. Steel mills 20 miles north of Ce-
dar Lake, Indiana were the suspected source of elevated zinc and lead concentrations
in its surficial sediments (Echelberger and Jones, 1984). Southerly winds carry these
and other airborne pollutants downwind to Cedar Lake. Atmospheric transport of mer-
cury from combustion sources has been implicated in mercury fish consumption adviso-
ries that now include 41 states (U.S. EPA, 2000).
The airshed of New York's Adirondack mountain lakes extends all the way down
to the lower Ohio River valley. Emissions from coal-fired electrical generating stations
in Indiana, Kentucky, and Ohio produce sulfur dioxide gas that is converted to sulfuric
acid in the atmosphere and falls as acid rain hundreds of miles away in the
Adirondack Mountains.
Findings at Siskiwit Lake on Isle Royale in Lake Superior illustrate that the entire
earth is the airshed for some organic pollutants. Isle Royale is a national park and has
no sources of a group of toxic chemicals known as polychlorinated dioxins and furans,
which are produced by combustion of domestic and industrial waste. However, these
contaminants were measured in surficial sediments in Siskiwit Lake (Czuczwa et al.
1984). These and other chemicals are now known to be distributed worldwide by
global atmospheric transport (Simonich and Hites, 1995).
The bottom line is that we must consider airshed effects in managing our lakes.*
17
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Managing Lakes and Reservoirs
Photosynthesis: process in
which plants use sunlight,
nutrients, water, and carbon
dioxide to produce energy
necessary for growth.
Oxygen is a byproduct of
photosynthesis.
Inorganic: chemical
compounds that do not
include hydrocarbons.
Oxygen saturation: when
dissolved oxygen in wafer is
in equilibrium with oxygen in
the atmosphere it is considered
saturated. The amount of
oxygen that fresh water can
contain varies with
temperature. Cold water can
contain more oxygen at
saturation than can warm
Water. During algal blooms,
photosynthesis rates can be
high enough that dissolved
oxygen can become
super-saturated (greater than
100% of the saturation value).
Decomposition: the
transformation of organic
molecules (e.g., sugar) to
inorganic molecules (e.g.,
carbon dioxide and water)
through biological and
non-biological processes.
Surface and subsurface drainage from fertile (nutrient-rich) watersheds
results in biologically productive lakes, and drainage from infertile (nutri-
ent-poor) watersheds results in biologically unproductive lakes. The relative
fertility of watersheds and, thus, of lakes varies locally and regionally.
Oxygen enters lakes from the atmosphere and as a byproduct of
plant photosynthesis. The oxygen content of water remains in approxi-
mate equilibrium with the oxygen content in the atmosphere: excess oxy-
gen produced by photosynthesis diffuses into the atmosphere while
oxygen consumed by respiration is replaced by oxygen diffused from the
atmosphere back into the water.
Diffusion is a relatively slow process and it sometimes cannot keep
up with oxygen consumption and production reactions within the lake.
For example, bacterial decomposition of organic wastes in lake sediments
may consume oxygen at a much greater rate than it can diffuse or mix
back in, resulting in low oxygen levels.
When the loss of oxygen from the water exceeds its input, the oxygen
content of the lake water declines. If the dissolved oxygen becomes severely
depleted, the lake can become anoxic, causing odors, fishkills, and increases
in undesirable forms of some nutrients. For example, dissolved oxygen is
very important in controlling chemical reactions in lake water. Of the two
most prevalent forms of inorganic nitrogen, nitrate (NOa") and ammonia
(NhU*), nitrate occurs where oxygen is plentiful; ammonia, when dissolved
oxygen is absent.
If bottom waters become anoxic, phosphorus otherwise bound in iron
compounds in the sediments breaks its chemical bonds and re-enters the
water in dissolved form, where it can be used by algae for more growth.
This process is referred to as internal loading of phosphorus. Such internal
loading may be a significant source of nutrients in some lakes.
Other chemically reduced forms, such as hydrogen sulfide, which has
a rotten egg odor, may also form in an anoxic hypolimnion.
Watershed Characteristics
Characteristics of watersheds — particularly size, topography, local geology, soil
fertility and erodibility, and land cover — influence the amount and nature of ma-
terials entering lakes.
^ Size. Lakes with large watersheds can be more affected by people's ac-
tivities than lakes with small watersheds and the same intensity and na-
ture of human activity (Fig. 2-6). This is true simply because more land is
draining into the downstream lake. When such large watersheds are dis-
turbed, they deliver more water, sediments, nutrients, and other pollutants
to streams and lakes.
On the other hand, lakes with large watersheds may respond more
quickly to watershed improvements. For example, improved runoff quality
resulting from land management in large watersheds will more rapidly
flush out poor-quality lake water than similar improvements in small wa-
tersheds. A large watershed is generally considered as one with more than
7 to 10 acres of watershed for each acre of lake. For example, using this
criterion, a watershed of 1,000 acres would be considered large for a
100-acre lake.
18
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CHAPTER 2: Ecological Concepts
Large Watershed
Small Watershed
Lake Surface Area =100 acres
Less runoff
Less sediment and nutrient loading
Longer hydraulic residence time
Lake Surface Area = 100 acres
More runoff
More sediment and nutrient loading
Shorter hydraulic residence time
Figure 2-6.—Watershed size can affect many important lake characteristics. Lakes
receive water, nutrients, sediments/ and other materials from their watersheds.
Larger watersheds, relative to lake size, deliver proportionately more of these mate-
rials to the lake.
Land slope. Steep slopes increase the velocity of surface water runoff,
thus increasing the likelihood that soils and other particulates will detach,
be caught up by the runoff, and be transported down the watershed and
into the water.
Geology. Regional geology controls the type of minerals and nutri-
ents that may enter a lake. For example, a deep alpine lake located in a
granitic watershed in the Colorado Rockies is almost certain to have
pristine, crystal clear, high quality water but very low biological productiv-
ity and poor fishing. On the other hand, a lake basin situated in rich alluvial
soils will likely have poor water quality because of its high turbidity, high
concentrations of nutrients and organic matter, frequent algal blooms, and
abundant aquatic macrophytes.
Soil type* The erosion and runoff potential of soils is related to their
cohesiveness and permeability. Loose-structured soils of intermediate
particle size like silts are most susceptible to erosion because they are
less cohesive than clays (smallest particles) but smaller than sands
(Novotny and Olem, 1994). Soils of larger particle size like sands are
much more permeable so water soaks into them more quickly rather
than running off. Runoff is greater on clay soils that are more tightly
packed and contain smaller pores.
19
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Managing Lakes and Reservoirs
V Land cover. The amount and type of materials carried by runoff from
a watershed depend primarily upon the cover on the land (Fig. 2-7). For
example:
• Bare ground has no protection from the erosive force of rain drops.
Rain drops hitting bare soil strike the ground with such force that soil
is ejected into the air, leaving a tiny "impact crater." As more and
more rain falls, these craters connect to form channels that carry
away the water and the loose soil.
• Impermeable surfaces (roads, parking lots, roofs) do not allow
water to percolate into the soil. Instead, water flows off the surface
and enters drainage channels. A greater proportion of impermeable
surfaces yields more runoff. For example, in an urban area, 90 percent
of the rainfall would likely become runoff while in a forest only 10
percent might run off (Fig. 2-7).
• Dense vegetation cover (high grasses, shrubs, trees) reduces the
erosive force of raindrops and provides resistance to flowing water.
Both of these actions help protect soil from erosion and increase
infiltration.
• Human activities that place additional materials on the land
(fertilizers, pesticides, septic systems, solid waste dumps, road salt, etc.)
greatly increase the amounts and types of materials reaching lakes and
streams.
Water runoff is affected by land cover
FOREST
AGRICULTURE
10-20% runoff
50-60% runoff
80 - 90% infiltrates
RESIDENTIAL
40 - 50% infiltrates
URBAN
40-50% runoff
90-100% runoff
50 - 60% infiltrates
Figure 2-7.—General relationships between land cover and runoff: runoff is reduced
on land with vegetative cover and increased on land with impermeable surfaces such
as roads, parking lots, and roofs. Adapted from Marsh and Barton, 1975.
20
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CHAPTER 2: Ecological Concepts
Lake Morphometry
A lake's physical dimensions (morphometry), which influence lake water quality and
productivity levels in a number of ways, are largely established when a lake forms. A
bathymetric map (Fig. 2-8) depicts the depth contours of a lake and allows you to
determine its surface area, maximum depth, mean depth, and shoreline length.
Bathymetric maps clearly show drop-offs and bars — features important to anglers.
Some of the more important morphometric parameters to consider for
lake management include:
^ Surface area (Ao)f units = acres (ac) or hectares (ha): important for
managing lake uses.
^ Maximum depth (Zmm); units = feet (ft) or meters (m): the loca-
tion where water is deepest — influences stratification and the propor-
tion of water in which algae can grow. For example, most water in shallow
lakes may have enough light for algae to grow, but in deeper lakes, much of
the deep water does not have enough light for algae (Fig. 2-9).
^ Mean depth ( ~z ) units = feet (ft) or meters (m): average depth of
the lake calculated by dividing the volume by the surface area (z = V/A0).
T Volume (V); units = cubic meters (m3) or acre-feet: total amount of
water in lake — influences dilution of inflowing nutrients, affects hydraulic
residence time.
Steep
slope
Depth contour line
Shallow
slope
Clear Lake
153 acres
Max.Depth = 38'
Surveyed: 6/8/83
Figure 2-8.—Bathymetric map for Clear Lake. Large shallow sloped areas could sup-
port an extensive littoral zone. Steeper sloped areas indicate drop-offs important for
fishing. The maximum depth is indicated by the cross.
Littoral zone: that portion
of the lake lying within the
photic zone. Rooted plants
can grow here and sediments
support a rich biological
community.
21
-------
Managing Lakes and Reservoirs
Photic zone: that area of a
lake having sufficient light to
support photosynthesis.
Aphotic zone: that area of
the lake too dark to support
photosynthesis.
J
Lake Depth and Productivity
Deep Lake Shallow Lake
Limit of light
penetration
•Small % of lake volume
is in photic zone.
•Greater mean depth
•Most of lake volume
is in photic zone
•Smaller mean depth
Figure 2-9.—Because less of their overall volume is in the photic zone, deep lakes are
less able to support plant growth, while shallow lakes with a proportionally larger
lake volume within the photic zone can support plant growth.
Lake Shape & Orientation and Wind
Fetch
Wind Direction
•long fetch = more
internal mixing
Wind Direction
•short fetch = less
internal mixing
Figure 2-10.—Wind fetch is one factor that affects the amount of wind mixing that oc-
curs in surface waters. A long, unimpeded length of lake along the primary wind di-
rection allows waves to grow higher.
Fetch (ft. or m.): longest uninterrupted distance over which the wind
blows across the lake — varies with wind direction, and affects wave height
and vertical mixing of water (Fig. 2-10). A lake with a very long wind fetch
may be more turbid than a lake of the same size where the fetch is shorter.
22
-------
CHAPTER 2: Ecological Concepts
Shoreline Length (L); units = meters (m) or feet (ft): the total
length of the shoreline encompassing the lake (lake circumference). This
distance represents the total amount of lake front available for activities
such as building homes and for lake edge effects (shoreline erosion, litto-
ral habitat, etc.).
Shoreline Development (Di); unitless: measure of "roundness" of
lake, is the ratio of the length of the shoreline to the circumference of a cir-
cle whose area is equal to that of the lake. A perfect circle has a shoreline
development value of 1.0. As the shape of the shoreline becomes more ir-
regular, the value increases. Irregularly-shaped reservoirs with numerous
embayments (coves) can have shoreline development values exceeding 3.
Lakes with very irregular shorelines have more nearshore shallows for
rooted plant growth and more shoreline for houses and shoreline erosion
— all of which may increase productivity in the lake (Fig. 2-11). Shoreline
development can be determined by the following equation:
Lake Shape and Shoreline
Length
Round Lake Crooked Lake
Surface Area = 100 acres
Shoreline length = 7,400 ft
DL=1.00
Area = 100 acres
Shoreline length = 12,000 ft
DL = 1.62
Figure 2-11 .—Each of these lakes has the same surface area size — 100 acres. The irreg-
ular-shaped Crooked Lake has a much larger shoreline length for littoral plant growth,
home sites, and shoreline erosion.
Lakes v. Reservoirs
In contrast to glacial lakes that may be many thousands of years old, most reservoirs
in the western hemisphere have been constructed within the past 100 years, although
some are much older. For example, the Romans built Proserpina Dam in Spain in the
second century and the lake is still being used for recreation and as a water supply.
Reservoirs have been built for many purposes, often for multiple uses, including: wa-
ter supply, flood control, power generation, recreation, and navigation.
While the same basic physical, chemical, and biological processes occur in
reservoirs and natural lakes, the age, morphology, location in the drainage basin,
and hydrological characteristics make them unique ecosystems (Cooke and Ken-
nedy, 1989).
23
-------
Managing Lakes and Reservoirs
Because reservoirs are often flooded river valleys, they often are long
and narrow rather than circular or ovid like glacial lakes, and they
tend to have irregular shorelines (Figure 2-12).
While natural lakes often receive water from several small streams
and groundwater, a single large tributary usually supplies reservoirs.
Water leaves drainage lakes via an unregulated surface discharge but
reservoir releases are most often discharged through submersed,
controlled gates (Cooke and Kennedy, 1989).
Many reservoirs are sited such that they have large watersheds to
meet water supply or flood storage needs. Therefore, reservoirs often
have watersheds many times larger than those of natural lakes. These
larger watersheds deliver more water, sediments, and nutrients to
reservoirs.
.™&s*jg^- **z
Natural Lakes
• Smaller watershed area: lake surface area ratio
• Longer hydraulic residence time
• Simpler shape
• Surface outlet
boundary
Reservoirs
• Larger watershed area: lake surface area ratio
• Shorter hydraulic residence time
• More complex shape, higher DL value
• May have surface and/or subsurface outlet(s).
Figure 2-12.—General comparison between natural lakes and reservoirs. Source:
Moore and Thornton, 1988.
24
-------
CHAPTER 2: Ecological Concepts
•« RIVERS
-[LAKES [—•*-
MAIN STEM
"RUN-OF-THE-RIVER"
RESERVOIRS
MAIN STEM
STORAGE
RESERVOIRS
TRIBUTARY
STORAGE
RESERVOIRS
INCREASING HYDRAULIC RESIDENCE TIME
Figure 2-13.—Reservoirs occupy an intermediate position between rivers and natural
lakes along a continuum of aquatic ecosystems ranging from rivers to natural lakes.
Water residence time and the degree of riverine influence are primary factors deter-
mining the relative positions of different types of reservoirs (mainstem-run-of-the-
river, mainstem storage, and tributary storage impoundments) along the river-lake
continuum. Modified from Kimmel and Groeger (1984).
Actually, reservoirs and natural lakes are probably more alike than different.
Their physical, chemical, and biological conditions overlap greatly, as illustrated in
Figure 2-13. With regard to the environmental factors that control water quality
and biological productivity, reservoirs occupy an intermediate position between
natural lakes and rivers (Kimmel and Groeger, 1984).
Lake Processes
Lake Stratification and Mixing
The thermal properties of lakes and the annual circulation events they cause
probably have a greater influence on lake biology and chemistry than any other
factor. Lake water absorbs heat energy directly from sunlight and additional heat
from the air. The mixing action of wind helps distribute this heat throughout a
lake's surface waters.
As surface water warms up in the spring, it becomes lighter than the cooler,
more dense water at the lake bottom that does not receive this heat. This is just
one of the unique properties of water — its density changes with temperature
(see special box on Unique Properties of Water [next page]).
As the surface water continues to warm, the density difference between the
surface and bottom waters becomes too great for the wind energy to mix, and
the lake becomes stratified. Thermal stratification defines the condition in many
temperate lakes where warm surface waters overlie cold bottom waters.
• The well-mixed and uniformly warm surface waters are called the
epilimnion, while
• The uniformly cold, unmixed bottom waters are called the
hypolimnion (Fig. 2-14).
Stratification: process in
which several horizontal
water layers of different
density form in some lakes.
25
-------
Managing Lakes and Reservoirs
* The layer of
greatest temperature
change, the metalimnion,
presents a barrier to
mixing. The thermocline
is not a layer, but a plane
through the point of
maximum temperature
change. The epilimnion
and hypolimnion are
relatively uniform in
temperature. As the graph
illustrates, ice is much
less dense (lighter) than
water. Warm water is less
dense than cold water,
but more dense than ice.
Density changes most
rapidly at warm
temperatures.
The Unique Properties of Water
Water is a unique substance, and to understand how lakes behave, it is useful to un-
derstand water's physical and chemical properties. The molecular structure of wa-
ter and the way in which water molecules associate with each other dictate these
properties:
1. Water is an excellent solvent; many gases, minerals, and organic compounds dissolve
readily in it.
2. Water is a liquid at natural environmental temperatures and pressures. Although this prop-
erty seems rather common and obvious, in fact, it is quite important. If water behaved at
ordinary temperatures and pressures as do chemically similar inorganic compounds, it
would be present only as a vapor, and lakes would not exist.
3. The temperature-density relationship of water is also unique. Most liquids become in-
creasingly dense (more mass, or weight, per unit volume) as they cool. Water also rap-
idly becomes more dense as its temperature drops, but only to a certain point (Fig.
2-14). Water reaches its maximum density at 39.2°F (3.94°C), then it decreases slightly
in density until it reaches 32°F (0°C), the freezing point. At this point, ice forms and its
density decreases sharply. Ice, therefore, is much lighter than liquid water and forms at
the surface of lakes rather than at the lake bottom.
A second important consequence of the temperature-density relationship of water is
the thermal stratification of lakes. Energy is required to mix fluids of differing densities,
and the amount of energy necessary is related to the difference in density. In the case of
the water column mixing in lakes, this energy is provided primarily by wind. Therefore,
the changes in wafer density that accompany rapidly decreasing water temperatures in
the metalimnion during summer stratification are of great importance. The metalimnetic
density gradient provides a strong and effective barrier to water column mixing.
TEMPERATURE AND THE DENSITY OF WATER
5 10 15 20 25 30 °C
TEMPERATURE °C
THERMOCLINE
The density of water is
greatest at 4°C. Water
becomes less dense as it
warms or as it cools.
20-25 °C = 60-75 °F
15-20°C = 45-65 °F
4-15 °C = 39.2-45 °F
SSiEPILIMNION 20-25
METALIMNION 15-20
-5
1.00000
0.99900
0.99800
0.99700
0.99600
0.99500
0.92
0.91
0 5 10 15 20 25 30
-
i i i i i
LIQUID TO ICE ^
:_J
Figure 2-14.—The temperature-density relationship of water enables deep lakes to
stratify during summer. (* See explanation in side column.)
4. Water also has an unusually high specific heat. Specific heat is the amount of energy re-
quired to change the temperature of 1 g of water by 1 °C. Water also has a high latent
heat of fusion, which is the energy required to melt 1 g of ice at 0°C. These properties
make lakes slow to thaw and warm in the spring and slow to cool and freeze in the fall,
thus providing exceptionally stable thermal environments for aquatic organisms.
Additionally, because water gains and loses heat slowly, the presence of large lakes
can exert a significant influence on local and regional climate. A good example is the
Great Lakes, which have a dramatic effect on both the air temperature and on the pre-
cipitation in the states and provinces surrounding them. *
26
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CHAPTER 2: Ecological Concepts
• The two layers are separated by a zone of rapidly changing
temperature and density called the metalimnion — that layer of water
where the temperature changes by more than one degree Celsius for
each meter of water depth. In effect, the metalimnion acts as a lid
separating the epilimnion from the hypolimnion during stratification.
• Another term, the thermocline, defines that particular depth within
the metalimnion where the rate of change in temperature is greatest.
As the epilimnion cools in the late summer and fall, the temperature differ-
ence between layers decreases, and mixing becomes easier. With the cooling of
the surface, the mixing layer gradually extends downward until the entire water
column is again mixed and homogeneous (Fig. 2-15D). This destratification pro-
cess is referred to as the fall overturn.
Under ice cover during winter, the lake may again stratify but in reverse or-
der. The cooler, less dense water (< 4°C) overlies the dense water at 4°C, the
temperature of maximum water density (Fig 2-15A). When the ice melts and the
surface waters begin to warm up, the density differences with depth are minimal
and the lake again circulates during spring turnover (Fig 2-1 SB).
The extent of summertime thermal stratification in lakes depends on several
factors, including lake depth, wind fetch, wind exposure, and spring temperatures.
Most temperate lakes 5 to 7 meters deep stratify. However, even relatively deep
lakes may not stratify if they have large wind fetches or are unprotected by trees
or other wind barriers. On the other hand, a relatively shallow lake may stratify if
it is surrounded by bluffs or has a small wind fetch. A long, cool spring can allow
a deep epilimnion to develop, because slow warming allows for a longer period of
deep circulation. The thickness of the epilimnion may be very shallow when hot
weather causes early stratification after only a short circulation period.
Thermal Stratification and Overturn
ice
Winter
B.
0 10 20 30 °C
0 10 20 30°C
Temperature
profile
0 10 20 30 °C
0 10 20 30 °C
Figure 2-15.—The changing of the seasons in north temperate areas and the subse-
quent changes in lake temperature provide for alternating periods of thermal stratifi-
cation and circulation.
Dimictic: undergoing two
periods of mixing per year.
For example, north temperate
lakes often stratify during the
summer and winter, and have
periods of circulation in the
fall and spring.
Monomictic: undergoing
only one period of mixing
per year. For example,
lakes in the southern U.S.
may never get cold enough
to stratify during the winter.
Instead, one long period of
circulation lasts from fall to
spring.
Polymictic: shallow lakes
and reservoirs that circulate
frequently and stratify only
when winds are calm.
Deeper lakes subject to
strong, uninterrupted winds
may also not stratify.
Anoxia: a condition of no
oxygen in the water. Often
occurs near the bottom of
fertile, stratified lakes in the
summer and under ice in late
winter.
27
-------
Managing Lakes and Reservoirs
' Reservoirs and Stratification. Reservoirs may exhibit varying
degrees of thermal stratification. These differences are related to geo-
graphic location, operation, and morphometry (Cooke and Kennedy, 1989).
Reservoirs located in southern states gain significant heat due to the
warmer climate and longer duration of the summer period. Temperature
profiles for southern reservoirs often lack a pronounced thermocline, and
temperatures in bottom waters may be similar to those in the surface wa-
ters. Others may lack a distinct hypolimnion but will have both an
epilimnion and metalimnion. Shallow reservoirs exposed to the wind may
circulate much of the year and might stratify for brief periods during calm,
hot weather.
Spatial patterns in thermal structure are often observed in reservoirs.
The upper basin of reservoirs is often shallow and well mixed because of
tributary inputs and wind action. Deep water near the dam may be ther-
mally stratified throughout the summer, creating a reservoir with two dis-
tinctive habitats.
When the inflowing tributary water is warmer, and thus lighter, the wa-
ters will flow over the reservoir's surface and ultimately mix with the sur-
face waters. Colder and denser inflowing water will eventually settle into
the reservoir's bottom, with extensive mixing possible. Inflowing water
with a temperature and density intermediate to the reservoir's epilimnion
and hypolimnion can flow as a layer within the metalimnion (Cooke and
Kennedy, 1989). When several tributaries of different densities enter a res-
ervoir, several distinct density layers may be apparent ( Fig. 2-16).
•3 40 -
Xemperature Profile (9/14/99)
Epilimnion |
**
„ ^ Thermocline
Hypolimnion
12 14 16 18 2O 22 24 26 28 3O
Temperature (°C)
Conductance Profile (9/14/99)
Colorado
River—**
Las Vegas Wash
900 10OO 1100
Conductance (uS/cm)
Figure 2-16.—Temperature and specific conductance profiles from Lake Mead, Nevada.
The effects of surface inflows are easily detected as the high-conductance but warmer
discharge from the Las Vegas Wash overlies the lower-conductance but cooler dis-
charge from the Colorado River. Density layers such as these are evident in lakes and
reservoirs having multiple inlets of different temperatures (LaBounty, 2000).
28
-------
CHAPTER 2: Ecological Concepts
' Shallow Lakes. Shallow lakes, for example, those with a mean depth
of less than 10 feet, may have many periods of circulation. Lakes and reser-
voirs that circulate frequently and rarely stratify except during conditions of
calm wind are called polymictic. Deeper lakes having large fetches may
also be polymictic because strong winds blowing uninterrupted over the
water surface have enough energy to completely mix the lake. For exam-
ple, Florida's Lake Okeechobee, the largest lake (427,000 acres) in the
southeastern United States, is shallow (mean depth = 8.9 feet), has a large
wind fetch (nearly 37 miles), and is polymictic (Hanlon, 1999).
' Some Potential Consequences of Stratification. When a
lake initially stratifies, the hypolimnion is rich in dissolved oxygen from
early spring mixing of the water column and from oxygen production by
plants. However, because of the metalimnetic barrier, the hypolimnion is
isolated from gas exchanges with the atmosphere during the summer and
is often too dark for algae to photosynthetically produce oxygen. So a
hypolimnion can become anoxic during summer or winter thermal strati-
fication as decomposing organic matter consumes its reserve of dissolved
oxygen.
Hypolimnetic anoxia has very important consequences for lake pro-
ductivity and fishery management and thus is a major target for lake resto-
ration. For example, most fish need relatively high concentrations of
dissolved oxygen and cannot survive in an oxygen-deficient hypolimnion;
but the midsummer epilimnion may be too warm for them. In addition, un-
der anoxic conditions, nutrients such as nitrogen and phosphorus are re-
leased from the bottom sediments to the water column, where they
ultimately promote more algae production, organic matter decomposition,
and thus, more severe hypolimnetic oxygen depletion.
Is summertime thermal stratification good or bad for a lake? While
stratification of a productive lake may lead to an anoxic hypolimnion,
phosphorus release from sediments, and loss of fish habitat, the
metalimnion generally confines these problems to the hypolimnion during
the summer growing season.
Once the lake turns over in the fall, mixing these nutrients into the
surface waters rarely causes algal blooms, since, at that time, light and tem-
perature have more effect on algal growth than nutrients. Thus, stratifica-
tion helps keep the summertime surface waters less productive than they
otherwise might be.
The bottom line: remember that thermal stratification does not necessarily
cause lake problems. Lake problems are caused by excess phosphorus, nitrogen,
and sediments entering the lake from the watershed.
Photosynthesis and Respiration
Light energy from the sun fuels the lake ecosystem. As light strikes the lake sur-
face, a large proportion is reflected back and never enters the water (Fig. 2-17).
Of the remaining light some is scattered by suspended particles, some is absorbed
by dissolved color and organic material in the water, and finally, some is used by
algae and macrophytes (rooted plants) in photosynthesis to convert the light en-
ergy to chemical energy.
29
-------
Managing Lakes and Reservoirs
Light Attenuation
SUNLIGHT
\
Reflected
Scattered by particles
Absorbed by:
' -water " .' it_ ._.--_'.
:-V-dissolved color "
Lower boundary
of photic zone
(appx1% light level)
Figure 2-17.—Much of the sunlight striking the lake surface is reflected back. The re-
maining light is scattered and absorbed — with only a small portion available for
photosynthesis.
In photosynthesis, aquatic plants and algae use the energy from sunlight, car-
bon dioxide, and water to produce sugar, water, and molecular oxygen (Fig. 2-18).
The sun's energy is stored in the sugar as chemical energy.
Plant cells then convert the sugar, along with certain inorganic elements
such as phosphorus, nitrogen, and sulfur, into organic compounds such as pro-
teins, carbohydrates, and fats.
The rate of photosynthetic uptake of carbon to form sugar is called primary
productivity. The amount of plant material produced and remaining in the system
is called primary production — analogous to a crop in a farmer's field. While
in-lake photosynthesis normally produces the organic matter for the lake's food
CO2 + H2O + Nutrients + Sunlight
Photosynthesis
Respiration &
Decomposition
(CH2O) + H2O
Figure 2-18.—The equilibrium relationship between
photosynthesis and respiration-decomposition pro-
cesses. The photosynthetic conversion of light en-
ergy, carbon dioxide (COa), water (hfoO), and nutri-
ents into organic matter produces oxygen (Oa),
carbon, nitrogen, sulfur, and phosphorus in organic
compounds of high potential energy. Respira-
tion-decomposition processes tend to restore the
equilibrium by consuming oxygen and decompos-
ing organic materials. Adapted from Moore and
Thornton, 1988.
30
-------
CHAPTER 2: Ecological Concepts
, most lakes also receive significant inputs of energy in the forms of dissolved
and participate organic matter from their watersheds.
Molecular oxygen, which is also produced by photosynthesis, is the primary
source of dissolved oxygen in the water and of oxygen in the atmosphere. Oxy-
gen is required to completely break down organic molecules and release their
chemical energy. This process is called oxidation.
Plants and animals release this energy through a process called respiration.
Its end products — energy, carbon dioxide, and water — are produced by the
breakdown of organic molecules in the presence of oxygen (Fig. 2-18).
Because light is required, the primary (photosynthetic) production of or-
ganic matter by aquatic plants is restricted to the photic zone (see Fig. 2-9). The
thickness of the photic zone depends upon the transparency of the lake water
and corresponds to the depth to which at least one percent of the surface light
intensity penetrates. Below this, in the aphotic zone, the light is too weak to sup-
port a significant amount of photosynthesis.
The thickness of the photic zone may vary seasonally; for example, it may be
relatively thick in spring but can thin as the growth of plankton or presence of
suspended solids limits transparency and light penetration.
Aquatic Plant Productivity
v Algae* Algae are photosynthetic organisms that form the base of the
aquatic food chain and are grazed upon by zooplankton and herbivorous
fish. Microscopic algae that have little or no resistance to water currents
and live suspended in the water are called phytoplankton. Although some
phytoplankton species have flagella to help them move, even the flagel-
lated forms cannot overcome water currents. In other words, they are
planktonic.
Other lake or stream algae may be found primarily attached to sub-
strates in the water such as piers, rocks, and rooted plants. These at-
tached algae are known as periphyton.
The abundance (production) of photosynthetic algae is controlled
primarily by water temperature, light, nutrients, hydraulic residence time,
and consumption by herbivorous predators.
Algae are classified according to color: green algae, blue-green algae,
golden algae, and so on. The colors refer to the most visible pigment in the
cells — chlorophyll in green algae; chlorophyll, carotene, and phycobilins in
blue-green algae; and abundant carotene in golden algae. The green and
golden algae contain these pigments in specialized structures called
chloroplasts.
When viewed under a microscope, these distinct colored structures
(chloroplasts) are very visible. The blue-green algae, on the other hand,
do not have specialized structures and their pigment is evenly spread
throughout each cell.
During intense algal blooms of a single species, you can identify the
particular group of algae by the color of the lake water. Limnologists mea-
sure the amount of chlorophyll pigments in lake water to determine the
abundance of phytoplankton.
Respiration: process by
which oxygen is conveyed to
tissues and cells, and carbon
dioxide and water are given
off.
Zooplankton: Microscopic
animals that float freely in
lake water, graze on detritus
particles, bacteria, other
zooplankton, and algae, and
may be consumed by fish.
Planktonic: passively
floating or drifting. If mobile,
unable to move against water
currents.
Chlorophyll: the green
pigment in many types of
algae. The primary
photosynthetic pigment.
31
-------
Managing Lakes and Reservoirs
Blue-greens are the most primitive algae; they date back as far as 2.8
billion years (St. Amand, 1995). They were the first photosynthetic organ-
isms on Earth. Like bacteria, blue-greens have no membrane-bound
organelles within cells. Because they are more like bacteria, they are more
correctly referred to as Cyanobacteria.
Despite this primitive heritage, blue-greens possess several amazing
competitive advantages over other algal groups (Table 2-2):
• Some blue-greens can regulate their buoyancy by retaining gases,
thus allowing them to maintain their position in the photic zone.
• Some blue-greens have specialized structures called heterocysts
that they use to absorb atmospheric nitrogen (Nj) from the
water — a process called nitrogen fixation, also used by some
bacteria in the roots of legumes on land.
• Blue-green algae are often colonial, forming masses too large for
zooplankton predators to handle.
• Others have a mucilaginous outer covering that is unpalatable to
zooplankton.
• Some blue-greens produce neurotoxins or liver toxins when
stressed (Kotak et al. 1994). They inhibit predation by
zooplankton, but also have been implicated in numerous livestock
and domestic animal deaths.
Paleolimnology: the study
of lake sediments and the
relics preserved in them.
Table 2-2.— Algae are classified according to color. General characteristics of
the more common divisions are given.
ALGAE GROUP
Diatoms
(Bacillariophyta)
Green algae
(Chlorophyta)
Golden algae
[Chrysophyta]
Blue-green algae
(Cyanofaacferia)
Dinoflagellates
[Dinophyta]
CHARACTERISTICS
Have cell walls made from silica, chloroplasts are yellow-green, often
have early season dominance, cell walls may persist for thousands of
years in sediments where they are useful for historic water quality
studies (paleolimnology).
Chloroplasts are bright green, population growth often follows spring
diatoms, important food for zooplankton, occasionally cause nuisance
blooms especially when nitrogen concentrations in the lake are high.
Optimize their growth during the relatively cool waters of late
winter-early spring, taste and odor problems are often associated with
golden algae, may supplement photosynthetic production by
capturing food particles in the water.
Similar biologically to bacteria, no chloroplasts — color is distributed
evenly throughout cells, often form filamentous or spherical colonies,
are considered nuisance organisms, often dominate summer plankton
in productive lakes, most can regulate buoyancy, many are
nitrogen-fixers, some produce toxins.
Free-swimming organisms having two flagella, have forward-spiraling
swimming motion, blooms are associated with organic pollution, may
cause taste and odor problems in water, marine dinoflagellates are
responsible for "red tides."
When there is enough light for photosynthesis, the availability of nu-
trients often controls phytoplankton productivity. The difference between
how much of a particular element a photosynthetic organism needs and
how much is available exerts the most significant influence on lake pro-
32
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CHAPTER 2: Ecological Concepts
ductivity. TaWe 2-3 compares the supply of essential nutrients relative to
their demand. Phosphorus and nitrogen are the most used elements, and,
therefore, they are the most likely to affect lake productivity.
Table 2-3.— The listed elements are required for plant growth. Plant demand is
represented by the percentage of these essential elements in the living tissue of
freshwater plants. Supply is represented by the proportions of these elements
in world mean river water. The imbalance between demand and supply is an
important factor in limiting plant growth (Valentyne, 1 974).
ELEMENT
Oxygen
Hydrogen
Carbon
Silicon
NITROGEN
Calcium
Potassium
PHOSPHORUS
Magnesium
Sulfur
Sodium
Iron
SYMBOL
O
H
C
Si
N
Ca
K
P
Mg
S
Na
Fe
DEMAND BY
PLANTS (%)
80.5
9.7
6.5
1.3
.7
.4
.3
.08
.07
.06
.04
.02
SUPPLY IN
WATER (%)
89.0
11.0
.0012
.00065
.000023
.0015
.00023
.000001
.0004
.06
.0006
.00007
DEMAND
SUPPLY RATIO1
1
1
5,000
2,000
30,000
< 1 ,000
1,300
80,000
< 1 ,000
.0004
< 1,000
< 1,000
1 Percent of element in plant tissue •+• percent in available water. The higher the ratio, the scarcer the
nutrient. Phosphorus, in particular, is likely to limit plant growth in a lake. If more phosphorus is supplied,
however, plant growth is likely to accelerate unless and until limited by some other factor.
Phosphorus, in particular, can severely affect a lake's biological pro-
ductivity. Modern society produces rich sources of this element;
wastewaters, fertilizers, agricultural drainage, detergents, and municipal
sewage all contain high concentrations of phosphorus. If they enter the
lake, they can stimulate algal productivity — and then you may have nui-
sance algal blooms, noxious tastes and odors, oxygen depletion in the wa-
ter column, and undesirable fishkills during winter and summer.
Many lake management efforts target phosphorus when they're trying
to reduce algal production and improve lake water quality. You can pre-
vent phosphorus from entering a lake by controlling its sources; for exam-
ple:
• Using chemical flocculation in advanced wastewater treatment
plants;
• Using proper agricultural and land management practices;
• Improving septic systems; and
• Applying fertilizer carefully (see Chapter 6).
33
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Managing Lakes and Reservoirs
Over the past 20 years, in our attempt to curb eutrophication we
have increasingly tried to minimize phosphorus inputs to lakes.
• Methods for precipitating or inactivating phosphorus within the lake
are discussed in Chapter 7.
• A method for determining the amount of phosphorus loading from
the watershed is discussed in Chapter 4.
• Formulas for predicting lake phosphorus concentrations are given in
Chapter 5.
For infertile lakes with poor fishing, improving the fishery may be the
highest priority. So the managers of those lakes may choose to add phos-
phorus- and nitrogen-containing fertilizers to enhance fish production —
another lake management tool!
v Zooplankton. Freshwater lakes contain a richly diverse array of mi-
croscopic and macroscopic animals in the water column that float, drift,
or swim weakly (i.e., they are at the mercy of currents). These animals are
collectively known as zooplankton. The most significant groups of fresh-
water zooplankton are the cladocerans, copepods, protozoa, and rotifers.
Zooplankton populations face the same challenges as all other animals —
the need for food and oxygen, excretion of wastes, and reproduction. Al-
though they are tiny, the relative abundance and diversity of these organ-
isms dramatically influence energy flow, nutrient cycling, and community
dynamics within aquatic ecosystems.
(Left)
Daphnia, a large (about 2 to 3 mm
long) filter-feeding zooplankton.
Note the three embryos in the
brood pouch.
(Bottom)
Bosmina, a small (about 0.5 mm
long) filter-feeding zooplankton.
Planktivores: fish and
invertebrates that feed on
plankton.
34
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CHAPTER 2: Ecological Concepts
Zooplankton are the primary consumers of algae. Some are grazers,
or more specifically herbivores, since they consume plants. Many of the
zooplankton are filter feeders. They filter large quantities of water and
collect edible algae contained therein. Others are raptorial — they seize
specific algal particles or other zooplankton. At the community level, zoo-
plankton are of critical importance. They are the primary mechanism for
transmitting the energy of the primary producers (phytoplankton) to or-
ganisms at higher trophic levels in the food chain. The young of many
gamefish, minnows, and other fish such as shad feed on zooplankton.
These fish are known collectively as planktivores.
' Macrophyfes. Macrophytes are vascular plants — that is, they have
conducting cells to transport nutrients and liquid through their stems.
Aquatic macrophyte growth is controlled by many factors, including tem-
perature, light, sediment texture, sediment slope, and hydrostatic pressure.
Most rooted macrophytes obtain their nutrients from the bottom
sediments rather than the water and are restricted by light to the shallow
littoral water. The littoral zone (Fig. 2-1) is defined as that area of the lake
at and above the I percent light level. In other words, the littoral zone de-
fines the area where there is enough light at the sediments to support
rooted plant growth (Fig. 2-19).
Another aquatic macrophyte called duckweed is not rooted in the sed-
iments but floats at the water surface. Duckweed floats with the wind or
water currents and is not dependent on depth, sediment type, or water
clarity (Borman et al. 1997). It is often associated with eutrophic waters
and can multiply to large populations when adequate nutrients are present.
Too often, people refer to all rooted aquatic plants as weeds and their
goal is to eradicate them all from the lake. This thinking is short-sighted and
Figure 2-19.—Littoral vegetation zonafion of a typical lake.
35
-------
Managing Lakes and Reservoirs
disregards the importance of macrophytes to the lake ecosystem. The
rooted macrophytes with all their positive attributes make the littoral zone
the most productive and important aquatic habitat in freshwater lakes.
• Aquatic plant communities protect the shoreline from erosion by
dampening the force of waves and stabilizing soils.
• Rooted macrophytes also provide fish habitat and spawning sites,
waterfowl cover and food, and habitat for macroinvertebrates (i.e.,
insects, snails, etc.) (Nichols and Vennie, 1991).
• Many species of macrophytes, such as the white water lily and
pickerelweed, are aesthetically pleasing because they have beautiful
flowers or interesting forms.
But even some of the most beautiful aquatic plants can be undesir-
able exotics (non-natives). These include species such as Eurasian
watermilfoil, curly-leaf pondweed, water hyacinth, hydrilla, and purple
loosestrife. These plants can invade lakes and rapidly crowd out desirable
native plants. Lake managers should be able to identify these species and
should develop a plan to manage them if they are found in a lake.
Therefore, producing stable, diverse aquatic plant communities con-
taining high percentages of desirable species should be a primary lake
management goal from an economic and environmental perspective.
Phytoplankton Community Succession
As the growing season proceeds, a succession of algal communities typically oc-
curs in a lake (Fig. 2-20).
• Phytoplankton biomass tends to be low in the early spring because of
cool water temperatures and low light levels. Diatoms and sometimes
golden algae are often the dominant algal group at this time as they
can withstand these conditions and silica is more available following
spring (and fall) turnover.
• In late spring to early summer, algal biomass increases, and green algae
may replace diatoms.
• As summer approaches and the lake water warms up, blue-green algae
may dominate, forming dense growths in productive lakes.
• Water column mixing during fall overturn increases the supply of
nutrients, often resulting in a late season, but short-lived, bloom of
diatoms, blue-green algae, or dinoflagellates.
Sedimentation and Decomposition
Sedimentation occurs when particles (silt, algae, animal feces, and dead organisms)
sink through the lake water column onto the lake bottom. Sedimentation is a very
important process that affects phytoplankton biomass levels, phytoplankton com-
munity succession, and transfers of organic matter, nutrients, and particle-associ-
ated contaminants from the lake's upper layers to the bottom sediments.
Sedimentation of particulate organic matter from the water column to the
lake bottom provides a critical linkage between planktonic primary production
and the growth of bottom-dwelling organisms (such as aquatic insect larvae,
36
-------
CHAPTER 2: Ecological Concepts
Phytoplankton Biovolume - Lake Lemon
on nnn
ou,uuu
vn nnn
/U,UUU
oU.UUU
?5
Ecn nnn -
ou,uuu
O >tn nnn -
p ^tL^uuu
3
^ on nnn -
O oU,UUU
•2 on nnn -
fQ /iU,UUU
*in nnn -
IU,UUU
A
Blue-green algae >-.'* \
\
/
* \
Diatoms
ra l ' ' FL ^-^~~~~^ ^
/ ^^ ^ '' /^""""•Q — ^~"^i_
P^^ ^\ >' ./ Green algae *
._>^/ /^ ^*.^ .
... .-^.,-.T ?~^-.*- *».. --•- *
— i i — i i - i i
31-Mar 1-May 1-Jun 2-Jul 2-Aug 2-Sep 3-Oct
Date
Figure 2-20.—Seasonal succession of phytoplankton in Lake Lemon, Indiana, a pro-
ductive 1,600-acre reservoir (from Zorgorski and Jones, 1986).
clams, and crayfish) that eat this detrital organic matter and, in turn, are eaten by
larger predatory organisms, such as fish and turtles. The sedimentation of living
and dead plankton down through the water column is so pervasive that it is re-
ferred to as plankton rain.
Oxygen-consuming decomposition processes degrade settling plankton,
zooplankton feces, and other organic detritus particles in the water column and
bottom sediments. The respiration of all organisms (including bacteria, fungi, and
other microbes) drives organic matter decomposition, a collective term for the
net conversion of organic material back to inorganic compounds (see Fig. 2-18).
In the hypolimnion of productive lakes, sedimentation of organic matter
from the surface waters is extensive. And because there's so much algae and
other suspended particles, light penetrates the water column to the hypolimnion
only minimally (or not at all) so photosynthesis cannot occur. Under these condi-
tions, the oxygen consumed in the hypolimnion and bottom sediments during de-
composition (respiration) of this organic matter greatly exceeds the oxygen
produced. Also, as described earlier, the hypolimnion is isolated from the atmo-
sphere by a water density barrier known as the metalimnion. "The result, in pro-
ductive thermally stratified lakes, is a depletion — even complete absence — of
dissolved oxygen in the hypolimnion. Shallow productive lakes with a prolonged
snow and ice cover can suffer the same effects.
Marked chemical and physical changes are associated with oxygen depletion.
They include:
• Increased release of nutrients (phosphorus and ammonia), certain
metals (iron and manganese), and compounds (hydrogen sulfide and
methane) from the anoxic bottom sediments;
• Destruction of oxygenated habitats for aquatic animals; and
• Incomplete decomposition of sedimented organic matter (Fig. 2-21).
Plankton rain: the almost
constant settling of plankton,
live and dead, through the
water to the bottom
sediments.
Chemical oxygen
demand (COD):
Nonbiological uptake of
molecular oxygen by organic
and inorganic compounds
in water.
37
-------
Managing Lakes and Reservoirs
The inability of highly productive lakes to efficiently process all the organic
material produced through photosynthesis led limnologist Arthur Hasler to refer
to these overfed and obese lakes as being "physiologically senile" (Hasler, 1969).
Plant nutrient uptake, photosynthesis of
organic matter and dissolved oxygen.
• THERMOCLINE
Consumption of dissolved oxygen In
respiration-decomposition processes, nutrient
regeneration by organic mutter decomposition.
Accumulation of nutrients and organic
sediments, release of dissolved nutrients from
sediments to water.
Figure 2-21.—Influence of photosynthesis and respiration-decomposition processes
and organic matter sedimentation on the distribution of nutrients, organic matter, and
dissolved oxygen in a stratified lake. Source: Moore and Thornton, 1988.
Food Web Structure/ Energy Flow,
and Nutrient Cycling
In-lake plant production usually forms the organic matter base of the lake's food
web. Although some water bodies (especially rapidly flushed reservoirs) receive
important supplements of organic matter from river and stream inflow, most
lakes require a reliable level of algal and macrophyte production to maintain pro-
ductive food webs (Adams et al. 1983).
Some of the organic matter produced photosynthetically by the lake's pri-
mary producers (algae and macrophytes) is consumed by herbivores (grazers)
that range from tiny zooplankton to snails to grazing minnows.
Herbivores, such as the zooplankton, are fed on by planktivores (including
predatory zooplankton, aquatic insects, and planktivorous fish) that, in turn, pro-
vide a food source for the higher-level consumers such as piscivorous (fish-eating)
fish (bass, walleye, pike) and fish-eating birds (kingfishers, herons, ospreys, ea-
gles).
This general progression of feeding levels (also called trophic levels) from
primary producers, to herbivores, to planktivores, to increasingly larger preda-
38
-------
A
HSCiVORES
PLANKT1VORES
7— \
HERBIVORES
Energy
Flow
PRIMARY
PRODUCERS
Nutrients
DETRTTIVORES
& DECOMPOSERS
Energy Pyramid
recycle
•
Benthrvorous Fisri
Aquatic Food Chain
Figure 2-22.—The food-chain concept refers to the progression of feeding (or trophic)
levels from primary producers, to herbivores, to higher predators. As shown, this
process involves both the transfer of energy among lake organisms and the recy-
cling of nutrients. Because the available energy decreases at each trophic level, a
large food base of primary producers, herbivores, and planktivores is required to
support a few large game fish.
tors, constitutes a food chain (Fig. 2-22). The actual complex of feeding interac-
tions among all the lake's organisms is called a food web.
As shown in Fig. 2-22, the food chain concept also involves the flow of en-
ergy among the lake organisms and the recycling of nutrients.
The energy flow begins with light energy from the sun, which is converted
by green plant photosynthesis into the chemical energy represented by the or-
ganic matter produced by plants. Each subsequent consumer (herbivore, plankti-
vore, piscivore) transfers only a fraction (usually about 10 to 20 percent) of the
energy received on up the chain to the next trophic level (Kozlovsky, 1968;
Gulland, 1970).
Because of this inefficient energy transfer, a few large game fish depend on a
large supply of smaller fish, which depend on a very large supply of smaller herbi-
vores, which depend on a successively much larger base of photosynthetic pro-
duction by phytoplankton and other aquatic plants.
Finally, by constantly producing wastes and eventually dying, all of these organ-
isms nourish detritivores (detritus-eating organisms), bacteria, and fungi, which de-
39
-------
Managing Lakes and Reservoirs
rive their energy by decomposing organic matter. Organic matter decomposition
recycles nutrients required to produce plants. This nutrient regeneration occurs at
virtually every level of the food web, and only a small fraction of the organic mat-
ter produced ultimately accumulates as permanent bottom sediment.
In an actual food web within a lake, many different types of organisms live at
each trophic level, directly affecting their "neighbors" and indirectly influencing
other populations with which they interact. Species with significant influence in the
food web are called keystone species; they cannot be removed from the system
without causing ,a dramatic change in the community.
For example, piscivorous fish (bass, pike, etc.) are frequently keystone spe-
cies in lakes. They eat planktivorous fish that, in turn, eat zooplankton. If few
piscivores exist, either because of overfishing or degraded habitat, planktivorous
fish will increase, eliminating the large herbivorous zooplankton that eat algae.
Thus, algal populations increase and transparency decreases.
Figure 2-23 shows a more complex view of biotic interactions and nutrient
cycling in a lake or reservoir ecosystem. Biota in one trophic level affect those in
other trophic levels in many ways — directly through predation or changes in the
physical or chemical characteristics of the water, or indirectly through nutrient
cycling pathways. Understanding the complexity of these pathways is essential for
effective lake management.
In addition to their "keystone" role at the top of the aquatic food chain,
piscivorous fish are also valued as sport fish. Many fisheries managers try to maxi-
mize sport fish biomass to make anglers happy. However, optimal warm water
sport fish yields require higher nutrient levels and more overall lake productivity
(and thus poorer transparency) than may be desirable for other lake uses (Fig.
2-24). This situation becomes more problematic when both warmwater and
coldwater fisheries are desired as increasing nutrient levels can have significant
Increased Nutrient Loading
I*
Primary Productivity
Macrophytes
I
Fish Cover
Mean Size of
Zooplankton
Anoxic Nutrient
Release
Sedimentation
Rate
Zooplankton
Refuge
I
Hypolimnetic
Deoxygenation
Figure 2-23.—A conceptual model of the biotic and chemical interactions involved in the
food web and their influence on eutrophication. A plus (+) indicates a positive influence;
a minus (—) indicates a negative influence.
40
-------
CHAPTER 2: Ecological Concepts
WATER QUALITY
« . i
FISHERY YIELD
100
J 10
t
in
O
O
CO
I Illl
I Mill
i i nil 111 i i
nil
FISH YIELD
o 1 -HIM i i i nun > i i nun i i i mill Q
1 10 100
10
0.1
I
•o
S
3
UJ
>
I
to
1000
MEAN SUMMER CHLOROPHYLL a (fig L"1)
Figure 2-24.—Relationship between lake characteristics (e.g., Secchi depth, chlorophyll)
and management objectives (e.g., water quality, fishery yield). Arrows denote de-
creased clarity and increased fish yield. Modified from Wagner and Oglesby (1984).
impacts on the coldwater fisheries (see Chapter 5 and Fig. 5-9 for additional dis-
cussion).
For example, a lake can become eutrophic at total phosphorus concentra-
tions of 40 |lg/L, but Ney (1996) found that sport fish biomass in reservoirs prob-
ably does not peak at less than 100 \iglL, The upshot of this is that your lake
cannot necessarily provide both clear water quality and abundant fish popula-
tions at the same time. Consequently, you must clearly establish your lake man-
agement priorities to avoid conflicts among lake uses.
Eutrophication
Lakes are temporary (in a geologic sense) features of the landscape. The Great
Lakes, for example, have existed in their current shapes for only about 12,000 years.
Over tens to many thousands of years, lake basins change in size and depth as a re-
sult of climate, movements in the earth's crust, shoreline erosion, and the accumula-
tion of sediment. Eutrophication is the term used to describe this process.
Eutrophication is defined as the excessive addition of inorganic nutrients, or-
ganic matter, and silt to lakes, thereby increasing biological productivity (Cooke
et al. 1993). The key part of this definition is the biological response of the lake to
these additions; high phosphorus concentrations alone do not determine
eutrophication.
The classical lake succession sequence (Fig. 2-25) is usually depicted as a uni-
directional progression through the following series of phases (trophic states)
having these general characteristics:
41
-------
Managing Lakes and Reservoirs
Oligotrophy: lack of plant nutrients keeps productivity low; lake
contains oxygen at all depths; clear water; deeper lakes can support
trout.
Mesotrophy: moderate plant productivity; hypolimnion may lack
oxygen in summer; moderately clear water; warmwater fisheries only
— bass and perch may dominate.
Eutrophy: contains excess nutrients; blue-green algae dominate
during summer; algae scums are probable at times; hypolimnion lacks
oxygen in summer; poor transparency; rooted macrophyte problems
may be evident.
NATURAL EUTROPHICATION
MAN-IN0UCED EUTROPHICATION
SS: OLIGOTROPHY
EUTROPHY/
HYPEREUTROPHY
FERTILIZERS AND
PESTICIDES
EUTROPHY/
HYPEREUTROPHY
Figure 2-25.—
(left column) The progression of natural lake eutrophication through nutrient-poor
(oligotrophy) to nutrient-rich (eutrophy) stages. The diagram depicts the natural process
of gradual nutrient enrichment and basin filling over a long period of time (e.g., thou-
sands of years).
(right column) Human-induced or cultural eutrophication in which this process is
greatly accelerated by increased inputs of nutrients and sediments into a lake, as a re-
sult of watershed disturbance by humans.
42
-------
CHAPTER 2: Ecological Concepts
• Hypereutrophy: algal scums dominate in summer; few macrophytes;
no oxygen in hypolimnion; fishkills possible in summer and under
winter ice.
These lake trophic states correspond to gradual increases in lake productiv-
ity from oligotrophy to eutrophy.
Evidence obtained from sediment cores, however, indicates that changes in
lake trophic status are not necessarily gradual or unidirectional. If their water-
sheds remain relatively undisturbed, lakes can retain the same trophic status for
many thousands of years. For example, the Italian lake, Lago di Monterosi, re-
mained oligotrophic for 22,000 years until the Romans built a road through its
watershed in 171 B.C. This disturbance boosted productivity in the lake to
eutrophic proportions (Frey, 1980). Productivity subsequently declined as the wa-
tershed restabilized and delivered less nutrients to the lake (Fig. 2-26).
Lessons to learn from this and other examples like it are that eutrophication
is not necessarily a natural process, and when it does happen, it is often revers-
ible. In contrast, rapid changes in lake nutrient status and productivity do result
from human disturbances to the watershed, rather than gradual enrichment and
filling of the lake basin through natural means.
People cause cultural eutrophication when their use of the land dramatically
increases nutrient, soil, or organic matter loads to the lake. They can drastically
shorten a lake's lifespan by clearing forests, building roads, cultivating fields, devel-
oping residential communities, and discharging wastewater — all these activities
increase the nutrients and soil that eventually move into the lake (see Chapter 6's
sections on nonpoint and cultural sources).
Some lakes, however, are naturally eutrophic. In fact, if they lie in naturally
fertile watersheds, they have little chance of being anything other than eutrophic.
Unless some other factor such as higher turbidity or an increase in the hydraulic
flushing rate intervenes, these lakes will naturally have very high rates of primary
production.
Natural and constructed lakes age by the same processes — nutrient en-
richment and basin filling — but at very different rates. As a rule, reservoirs be-
come eutrophic more rapidly than natural lakes, because most reservoirs receive
higher sediment and nutrient loads than do most natural lakes. They may even be
eutrophic when initially filled. Reservoirs, especially those with hypolimnetic out-
lets, trap sediments more efficiently than they retain nutrients; therefore, they age
primarily by the filling of their basins with riverborne silts and clays.
Lake
Formed
(26,000 years
before present)
1
Oligotrophic
Trophic equilibrium
re-established
(1 ,300 BP)
Land clearing i
forViaCasia Present
(2.200 BP) . y ^
I.I.I
Eutrophic Oligotrophic
Figure 2-26.—Trophic state timeline for Lago di Monterosi, Italy. This lake remained
oligotrophic for over 20,000 years. Following a brief period of eutrophy, caused by
human land use, the lake returned to oligotrophy naturally.
43
-------
Managing Lakes and Reservoirs
(a)
NUTRIENT INPUTS
INTERNAL
UJ
U
CO
01
I
LU
cc
(b)
AVAILABILITY OF HABITAT AND DETRITUS
HABITAT
LABILE DETRITUS
(c)
BIOLOGICAL PRODUCTIVITY
PLANKTON
(2)-
| UPSURGE—[-DEPRESSION-]
TROPIC
"INSTABILITY"
TROPHIC
STABILITY
t_
BASIN FILLING BEGINS
RESERVOIR AGE
Figure 2-27.—Factors influencing biological productivity or itrophic progression^ In a reser-
voir in the initial years after impoundment: (a) internal nutrient loading from the flooded
reservoir basin and external nutrient loading from the watershed, (b) availability of habi-
tat (flooded vegetation) and unstable terrestrial detritus supporting macroinvertebrates
and fish, and (c) plankton and fish production. The initial period of trophic instability (i.e.,
upsurge and depression) is followed by a less productive, but more stable, period in the
maturing reservoir (1). However, disturbances or land-use changes in the watershed can
result in increases (2) or decreases (3) in external nutrient loading and, consequently, in
reservoir productivity. Modified from Kimmel and Groeger (1986).
44
-------
CHAPTER 2: Ecological Concepts
However, unlike natural lakes, reservoirs often do not go through the classi-
cal trophic progression from oligotrophy to eutrophy. In fact, newly filled im-
poundments usually go through a relatively short period of trophic instability in
which a highly productive period (the "trophic upsurge") is followed by a decline
in lake productivity (the "trophic depression"), eventually reaching a less produc-
tive but more stable trophic state (Fig. 2-27).
The trophic upsurge results largely from nutrient inputs from both external
sources (the watershed) and internal sources (leaching of nutrients from the
flooded soils of the reservoir basin and decomposition of terrestrial vegetation
and litter).
The trophic depression is, in fact, the system's first step toward its natural
productivity level dictated by the level of external nutrient inputs. Flooding of
soils, vegetation, and litter as the new reservoir fills contributes to both abundant
food and expanding habitat. As the reservoir matures, both food and habitat re-
sources decline, fish production decreases, and the fish community stabilizes.
This trophic upsurge and depression — the "boom and bust" period — in-
evitably raises simultaneous concerns about poor water quality and false hopes
for a higher level of fishery yield than can be sustained over the long term. Ulti-
mately, in reservoirs and in natural lakes, the nature of the watershed (and what
people do there) will determine the water quality, biological productivity, and
trophic status of the system.
Finally, we must remember that while eutrophication is an important ecolog-
ical process in lakes, it doesn't cause all lake ills. High and low water levels, acid
precipitation, mercury, pesticides, and other toxins are among the many other
problems that may affect lakes (see Chapter 4). Keep these factors in perspective
as you assess lake conditions and develop management plans.
Ecology's Place in Lake Protection,
Restoration, and Management
We must establish the ecological basis for lake management if we are to succeed
in managing and maintaining sustainable lake ecosystems. As Osgood (1996) said
so well, "ecologically-based lake management is an active process that identifies
and engages the lake community in meaningful, measurable, and sustainable ac-
tions that seek to attain a desired condition which, at a minimum, stabilizes the
lake ecosystem."
The understanding gained from this chapter will help you evaluate the po-
tential benefits and limitations on lake protection and restoration approaches
and techniques described in the rest of this manual.
Most of what we know about lake and reservoir management has been
learned in the last 30 years through experience gained from many studies con-
ducted throughout the world. Experience gained from previous management ef-
forts leads to the following conclusions:
I. There is no panacea for lake management or restoration problems;
different situations require different approaches and solutions.
2. A complex set of physical, chemical, and biological factors influences lake
ecosystems and affects their responsiveness to restoration and
management efforts.
45
-------
Managing Lakes and Reservoirs
3. Because of the tight coupling between lakes and their watersheds, good
conservation practices in the watershed are essential for improving and
protecting lake water quality.
4. Internal nutrient loading and recycling may continue to hamper lake
recovery even after watershed sources are controlled. The relative
importance of external versus internal nutrient sources must be
evaluated by a diagnostic lake study.
5. The physical, chemical, and biological components of lake ecosystems
are intricately linked. Actions targeting one component will likely affect
another. For example, lake renovation to enhance water quality by
limiting nutrients and thereby reducing algal production will also
decrease fish production. You must decide what you want to accomplish
and set priorities.
6. To be sustainable, lake renovation and management objectives must
consider the uses that the natural condition of the lake (and its
watershed) can support most readily.
In summary, the character of a lake or reservoir is determined by a complex
set of physical, chemical, and biological factors that vary with lake origin, its re-
gional setting, and the nature of the watershed. Important factors include hydrol-
ogy, climate, watershed geology, watershed to lake ratio, soil fertility, hydraulic
residence time, lake basin shape, external and internal nutrient loading rates,
presence or absence of thermal stratification, lake habitats, and lake biota.
In some situations, a natural combination of these factors may dictate that a
lake will be highly productive (eutrophic) and efforts to transform it to an unpro-
ductive, clear-water (oligotrophic) state would be ill-advised. However, if a lake
has become eutrophic or has developed other water quality problems as a result
of, for example, increased nutrient loading from the watershed, then this condi-
tion can be reversed and the lake improved by an appropriate combination of wa-
tershed and in-lake management. But the best thing to do is to take steps to
protect your lake and its watershed before problems develop.
The following chapters will discuss and compare a variety of lake and water-
shed management techniques. While reading through this information, remember
that the effectiveness of any lake management method or combination of meth-
ods will depend entirely on the ecological soundness of its application.
References
Adams, S.M., B.L Kimmel, and G.R. Ploskey. 1983. Organic matter sources for
reservoir fish production: A trophic-dynamics analysis. Can.J. Fish Aquat. Sci.
40:1480-95.
Borman, S., R. Korth, and J. Temte. 1997. Through the Looking Glass — A Field
Guide to Aquatic Plants. Reindl Printing, Inc., Merrill, Wl.
Cooke, G.D. and R. H Kennedy. 1989. Water Quality Management for Reservoirs
and Tailwaters. Report I: in Reservoir Water Quality Management Techniques.
Tech. Rep. E-89-1. U.S. Army Corps Eng., Washington, DC.
Cooke, G.D., E.B. Welch, S.A. Peterson, and P.R. Newroth. 1993. Restoration and
Management of Lakes and Reservoirs. 2nd ed. Lewis Publishers, Boca Raton, FL.
46
-------
CHAPTER 2: Ecological Concepts
Czuczwa,J.M.,B.D.McVeety,and R.A. Hites. 1984. Pol/chlorinated
dibenzo-p-dioxins and dibenzofurans in sediments from Siskiwit Lake, Isle
Royale. Science 226:568-9.
Echelberger, W.F.Jr. and W.W.Jones. 1984. Cedar Lake Restoration Feasibility Study.
ESAC-84-01. School Publ. Environ. Affairs, Indiana Univ., Bloomington.
Frey, D.G. 1980. The heritage of our lakes. The Key Reporter 45(4):2-4.
Gulland,J.A. 1970. Food chain studies and some problems in world fisheries. Pages
296-315 in J.H. Steele, ed. Marine Food Chains. Univ. Calif. Press, Los Angeles.
Hanlon, C.G. 1999. Relationships between total phosphorus concentrations,
sampling frequency, and wind velocity in a shallow, polymictic lake. Lake
Reservoir Manage. !5(l):39-46
Hasler,A.D. 1969. Cultural eutrophication is reversible. BioScience 19(5):425-31.
Horwitz, E.L 1980. Our Nation's Lakes. EPA 440/5-80-009. U.S. Environ. Prot.
Agency, Washington, DC.
Hutchinson, G.E. 1957. A Treatise on Limnology. John Wiley and Sons, New York.
Kimmel, B.L. and A.W. Groeger. 1984. Factors controlling primary production in lakes
and reservoirs: a perspective. Pages 277-281 in Lake and Reservoir Management.
N. Am. Lake Manage. Soc. and U.S. Environ. Prot. Agency. EPA 440/5/84-001.
Washington, DC.
. 1986. Limnological and ecological changes associated with reservoir aging.
Pages 103-109 in G.E. Hall and M.J.Van Den Avyle.eds. Reservoir Fisheries
Management: Strategies for the 80s. Reservoir Comm., Am. Fish. Soc., Bethesda,
MD.
Kotak, E.G., E.E. Prepas, and S.E. Hrudey. 1994. Blue-green algal toxins in drinking
water supplies;— Research in Alberta. Lake Line I4(l):37-40.
Kortmann, R.W. 1991. Phosphorus loading — look to the sky. Lake Line 11 (4): 19-20.
Kozlovsky, D.G. 1968. A critical evaluation of the trophic level concept. I. Ecological
efficiencies. Ecology 49:48-60.
LaBounty.J.F. 2000. Pers. Commun. Southern Nevada Water Authority, Las Vegas.
Marsh, W.M. and T.E. Borton. 1975. Inland Lake Watershed Analysis — A Planning
and Management Approach. Inland Lake Manage. Unit, Mich. Dep. Nat. Resour.,
Lansing.
Moore, L. and K. Thornton, eds. 1988. Lake and Reservoir Restoration Guidance
Manual. EPA 440/5-88-002. Prep, by N. Am. Lake Manage. Soc. for Office of Res.
and Devel., Envir. Res. Lab., Corvallis, OR, and Office of Water, Criteria Stand.
Div., Nonpoint Sources Branch, U.S. Environ. Prot. Agency, Washington, DC.
Ney.J.J. 1996. Oligotrophication and its discontents: effects of reduced nutrient
loading on reservoir fisheries. Am. Fish. Soc. Symp. 16:285-95.
Nichols, S.A. and J.G. Vennie. 1991. Attributes of Wisconsin Lake Plants. Inf. Circ.73.
Wis. Geolog. Nat. Hist. Surv., Madison.
Novotny, V. and H. Olem. 1994. Water Quality — Prevention, Identification, and
Management of Diffuse Pollution. Van Nostrand Reinhold, New York.
Osgood, D. 1996. The ecological basis for lake and reservoir management. Lake Line
16(2): 18-19,30-32.
Reckhow, K.H., M.N. Beaulac, and J.T. Simpson. 1980. Modeling Phosphorus Loading
and Lake Response Under Uncertainty: A Manual and Compilation of Export
47
-------
Monag/ng Lakes and Reservoirs
Coefficients. EPA 440/5-80-011. Off. Water Reg. Stand. U.S. Environ. Prot.
Agency, Washington, DC.
Simonich, S.L and R.A. Hites. 1995. Global distribution of persistent organochlorine
compounds. Science 269:1851 -54.
Sonzogni, W.C. et al. 1980. Pollution from land runoff. Environ. Sci. Technol.
14(2): 148-53.
St.Amand,A. 1995. Algae — nature's artwork. Lake Line, 15(3): 10-11,24-26.
U.S. Environmental Protection Agency. 2000. Update: National Listing of Fish and
Wildlife Advisories. EPA-823-F-00-016. Washington, DC.
ValentyneJ.R. 1974. The Algal Bowl: Lakes and Man. Misc. Special Publ.22. Dep.
Environ. Fish. Res. Board Canada, Ottawa.
Wagner, K.J. and R.T. Oglesby. 1984. Incompatibility of common lake management
objectives. Pages 97-100 in Lake Reservoir Management. EPA 440/5-84-001.
U.S. Environ. Prot. Agency, Washington, DC.
Yousef, Y. et al. 1978. Mixing effects due to boating activities in shallow lakes. Draft
Rep. OWRT, U.S. Dep. Int. Technol. Rep. ESEI 78-10, Washington, DC.
Zorgorski.J.S. and W.W.Jones. 1986. Lake Lemon Diagnostic/Feasibility Study.
ESAC-86-02. School Publ. Environ. Affairs, Indiana Univ., Bloomington.
48
-------
CHAPTER 3
Planning: From Goals
to Evaluation and
Around Again
Planning is the opposite of fate. If we don't accept c'est la vie (that's life —
that's how things happen), then we believe in planning. We believe in syste-
matically charting a course for the future to minimize conflict and maximize
the attainment of our goals.
Without a plan, year-to-year decisions are often inconsistent and management
is invariably inefficient. To effectively manage your lake, you must have a systematic
plan. And, you must also manage your watershed. Examples can be found in Water-
shed Protection: A Project Focus (U.S. EPA, 1995).
Planning is conducted formally or informally in all realms of life. While the
specifics vary, the planning process generally conforms to the model shown in Fig-
ure 3-1.
With this common sense approach, most citizens will readily accept the pro-
cess if they are involved from the beginning. In contrast, presenting them with a
plan prepared by professionals violates the basic premise of citizen participation
and seldom results in community ownership of the plan.
Citizens must be involved in the whole process because that's when various
— even contradictory approaches — can be aired and eventually reconciled into
1. Clarifying
Goals
2. Gathering
Information
3. Conceptualizing
the Alternatives
4. Making a
Formal
Decision
5. Defining
Measurable
Objectives
6. Implementing
7.
Evaluating
8. Repeating the
Process
Figure 3-1.— Generic planning process.
49
-------
Managing Lakes and Reservoirs
hile the goals
liscussed in this chapter
ire the social goals of
l,i|ii:i| _ •'>, ,; • „ ii
akeshore communities/
pncern for the integrity
» a, ,,.»,, >.
if the entire ecosystem
nust underpin all efforts
o meet human needs.
a plan that can work for the entire community. Otherwise, some citizens will not
only disagree with elements of the plan, but more importantly, will feel alienated
from the whole process of decision-making.
STEP 1; Clarifying Goals
Why We Care About a Lak
A goal is a desired state of affairs that is sufficiently broad and multifaceted to in-
sure unanimity.
Whose Goals?
The answer to this question depends on our definition of community. Some defi-
nitions are very narrow: one subdivision or just riparian owners. Broader defini-
tions would include the people living around the lake or even beyond.
Aldo Leopold suggested in 1949 that we go beyond the local area, beyond
our borders, beyond our time, and beyond our species to include future genera-
tions, the biotic community of plants and animals, and even the inorganic elements
(air, water, and soil) upon which all life depends. His Land Ethic embraced the con-
cept of Homo sapiens as part of a larger community rather than as masters of the
universe.
We abuse land because we regard it as a commodity belonging to us.
When we see land as a community to which we belong we may be-
gin to use it with love and respect (p. viii).
All ethics so far evolved rest on a single premise: that the individual is
a member of a community of interdependent parts. His instincts
prompt him to compete for a place in the community, but his ethics
prompt him also to cooperate (perhaps in order that there may be a
place to compete for) (p. 203).
The Land Ethic simply enlarges the boundaries of the community to in-
clude soils, water, plants, and animals or collectively: the land (p. 206).
A thing is right when it tends to preserve the integrity, stability, and
beauty of the biotic community. It is wrong when it tends otherwise
(p. 224).
While the goals discussed in this chapter are the social goals of lakeshore
communities, concern for the integrity of the entire ecosystem must underpin all
efforts to meet human needs.
"Whose goals" also differentiates between professionals and citizens. After
decades of professional management of natural resources, citizens are demanding
a voice in setting the agenda and in making final decisions. Some professionals are
comfortable with the notion of "experts on tap, not on top"; others find it diffi-
cult to be "public servants" to a largely urban citizenry rather than resource man-
agers. Their training to apply the single "best" technical solution to a problem
often makes them intolerant of citizens who question their "scientific prescrip-
tions."
50
-------
CHAPTER 3: Planning: From Goals to Evaluation and Around Again
But an increasingly sophisticated citizenry, with access to Internet information
and to other citizens dealing with similar situations, will no longer blindly follow the
recommendations of well-meaning, competent professionals. Increasingly, the term
"partnership" is being used to describe a new shared responsibility. Citizens now
determine the goals for their lake (within its legal and limnological limits), decide
which techniques to use, and help make it happen. They gather information, raise
funds, monitor water quality, and volunteer their physical labor on lake projects.
Primary Social Needs
Cultural Opportunity
Music
Art
Heritage
In 1974 the Technical Committee of the Water Resource Centers of the West-
ern States focused on a very broad question: "How does water contribute to so-
ciety?" They decided to first determine society's primary social needs and then
relate water to each need.
Twenty years later, research at the University of Wiscon-
sin-Stevens Point expanded the Committee's original list to
the following conditions that must be present in a balanced
social structure, as shown in Table 3-1.
Lakes contribute to most of these needs. People buy
lakefront property — and tourists visit the lake — because of
its natural beauty (aesthetics). The money they spend sup-
ports many rural communities. As the population ages, retir-
ees living on social security, investments, and pensions further
enhance the economic development of lake-rich areas.
Lakes provide an excellent opportunity for environmen-
tal education. Students not only learn about geology, chemis-
try, and biology, but they can also get involved in the political
and legal aspects of lake management.
"Going to the cottage" has many overtones — many of
them emotional. The special times at the lake with family and
friends become part of a rich emotional heritage that en-
riches generation after generation. Families and friends need
special places to build their emotional ties — a cabin on the
lake a long way from the cares of everyday life is one of the
very best.
Environmental security means clean lakes, a biodiverse
ecosystem of plant and animal life. These special parts of the
environment are especially vulnerable to pollution because
they lie at the bottom of watersheds — and so many people
use them (two-thirds of Wisconsin adults each year).
The high value Americans put on personal freedom and
individual rights often leads to conflicts over how we use our
land and water. We cherish the freedom lakes offer, but mis-
using that freedom can destroy many other lake benefits. Per-
sonal watercraft (jet skis) expand the freedom of a few but
diminish that of many others. Individual submarines may
cause a similar controversy in coastal waters and clear lakes.
While lake aesthetics typically affects more people in the
community (Klessig, 1973; Klessig et al, 1983; Shifferd, 1997),
Table 3-1.—Conditions that must be
present in a balanced social structure.
Aesthetic Opportunity
Natural beauty/landscapes
Attractive buildings/cities
Soothing interior spaces
Collective Security
International peace
National defense
Protection from internal disorder
Economic Opportunity
Good wages/job security
Return on investment
Efficient production
Educational Opportunity
Formal schools
Continuing education
Wisdom of elders
Emotional Security
Family bonds
Friendships
Sense of community
Environmental Security
Clean water
Clean air
Biodiversity
Individual Freedom and Variety
Private property rights
Consumer choices
Unrestricted speech/media
Individual Security
Health care
Police protection/prisons
Fire protection
Recreational Opportunity
Outdoor sports
Indoor leisure activities
Relaxation time
Spiritual Dimension
Humility before Supreme Being
Awe of nature
Set of moral principles
51
-------
Managing Lakes and Reservoirs
It*
'nless the lake
fmanager and the
ultimate decision-
Baking body know
i\vhat people expect
prom the lake and which
^expectations are not
Jbeing met, it will be
impossible to develop
land implement a plan
that meets human
"needs.
,
lakes also make a huge recreational contribution. Long home to traditional fish-
ing, swimming, and boating, lake water sports now also encompass sailing, scuba
diving, and wind surfing.
And some people cherish lakes as a spiritual setting — a place to reflect — a
place to look into the soul of the earth and find meaning in this world and the next.
When a community is clarifying its goals, it must determine what goals the
lake can meet. For example, a lake may be useless for fishing or boating but be an
aesthetic gem. All lake planning should explicitly — and by consensus — state
which goals are being addressed.
STEP 2; Gathering Information
What We Know About the Ecological and Sociological System
Step 2 gathers information needed by professionals and citizens to take the suc-
ceeding steps. Data-gathering assesses social needs, identifies problems, and in-
ventories physical resources. If little information is available regarding the lake and
its users, this step will require a significant investment of time and money.
Needs Assessment: Gathering
Information on the Local Community
Part of diagnosing any problem is to ask the patient (in this case the lake user)
"where it hurts." Unless the lake manager and the ultimate decision-making body
know what people expect from the lake and which expectations are not being
met, it will be impossible to develop and implement a plan that meets human
needs.
Many pieces of social data could be relevant. You can use numerous public
involvement techniques to obtain such information:
^ Census Data: These data, available every 10 years, provide a demo-
graphic baseline, a formal snapshot of the local population (age structure,
family composition, length of residency, urbanization of the area, migration
patterns, income and education levels). Population projections and other
trends can be graphed (Roser and Serow, 1984).
V Target Populations: A "needs assessment" systematically deter-
mines what people in the community feel they need. It begins with broad
discussions of community needs and ends with a prioritized list.
Again, ask "whose needs." Should lake planning focus on businesses
on the lake, on people who live around the lake, on everybody in the com-
munity — or on the people who use public access for boating and fishing,
or enjoy the public beaches, parks, and drives?
^ Nominal Group Process: The nominal group process (Delbecq, et
al. 1975) is an excellent way to begin the needs assessment. Unlike the
standard group meeting procedure, it does a good job of identifying all
concerns.
52
-------
CHAPTER 3: Planning: From Goals to Evaluation and Around Again
A typical group meeting makes a decision through the following se-
quence: a motion, discussion, and a vote. This standard procedure frus-
trates many people either because they feel intimidated about speaking up
before the group, or because a few dominant personalities monopolize the
discussion. And the motion is made before the discussion, which often ne-
cessitates numerous amendments.
In addition to its effectiveness in eliciting concerns and ideas, the
nominal group process can also be used to prioritize uses, problems, and
projects.
The process has many variations. In its simplest form, each participant
is first asked to write down a list of issues. The moderator then asks each
person to volunteer one issue, proceeding around the group until all is-
sues are transferred from individual written lists to sheets of paper hung
in view of the group. During this time, no one is allowed to discuss or de-
bate the appropriateness of anyone's suggestion.
After all issues are listed, the group might debate whether certain is-
sues should be combined. The discussion is led by the persons who sug-
gested the issues and is designed to help others understand them more
fully. The moderator must be forceful in keeping the discussion focused on
understanding each issue and eliminating duplication if the "authors" of
those issues agree. The discussion is never allowed to become a debate on
the merits of the issue.
Following the discussion, the moderator allows each person to select
a small number of issues to "save" by placing a mark or sticker next to
those issues. (The physical act of getting up and placing marks provides a
nice, refreshing break in the process.) Only the issues with votes are
"saved." At this stage each participant may be asked to give reasons why
they feel strongly about their top two or three items. After everyone has
shared those feelings, each participant is asked to indicate which two or
three of the marked items might be less important than the others. Again,
no debate is allowed, but if time allows, each participant may indicate why
these items are less important.
Participants then rank the saved issues by assigning 10 points with a
maximum of 4 points to any one item. The group then focuses on those
items (2-5) receiving the most votes (usually, there is a clear break be-
tween a top set and the rest). Be sure, however, to preserve all issues in
the minutes of the meetings. Thus, every person can see his/her contribu-
tion even if it didn't make the top set.
The nominal group method is designed to allow equal participation
by all members of the group; it neutralizes dominant personalities. If a
group exceeds 15 people, it is advisable to split the group into smaller
subgroups and proceed until each subgroup has identified its "saved" pool.
The "saved" pools are then combined and the entire group ranks the is-
sues in the combined pool by the same 10—4 procedure.
In larger lake communities, not everyone may be able to participate
directly, so you may want to form a task force or advisory committee to
represent the community before a city council or county board. The nom-
inal group process may still be a useful procedure for the task force or ad-
visory committee itself to use.
n addition to its
effectiveness in eliciting
concerns and ideas, the
nominal group process
can also be used to
prioritize uses, problems,:
and projects.
1
I he nominal group ;
method is designed to
allow equal participation
by all members of the
group; it neutralizes
dominant personalities.
53
-------
Managing Lakes and Reservoirs
Purveys are most
jseful in getting data
ibout actual behavior,
Ireferences, or concrete
ihoices.
EXJ.^.;. diii_ ', J_l 1 L*4_j , It—
In addition to identifying issues, participants leave the process with a
much higher sense of ownership than they do after participating in a stan-
dard meeting. After the nominal group experience, citizens identify with
the top concerns because they've actively helped select them.
' Social Surveys of Users — Behavior, Attitudes, and Pref-
erences* The most systematic way to obtain social data is to develop a
well-designed survey and have a professional survey agency conduct inter-
views or send out mail questionnaires. These results are not biased by
group discussion at the time of the survey, peer pressure, or the feelings of
the person conducting the interviews.
Surveys are most useful in getting data about actual behavior, prefer-
ences, or concrete choices. A survey can determine how many boats a
person owns and how many days s/he uses their cottage each year and
whether the annual meeting of the lake district should be held on Saturday
afternoon or Sunday morning.
Surveys are less useful for policy options, which are complex and hard
to describe in a single question; too often, answers are based on factors not
considered by the survey. Surveys should not substitute for group discus-
sion, voting in person at community meetings, and democratic decision-
making.
The lake organization officers, with professional help from a local uni-
versity or Extension office, could do their own survey by sending a ques-
tionnaire to residents, property owners, and possibly even public users of
the lake. The results would identify concerns and tell the board what ac-
tivities are most common and what activities are desired but not being ful-
filled.
When you survey lake residents, you should contact the entire popu-
lation; part of the purpose of such a survey is to give people a sense of
participation in the planning process. You can sample other lake users by
using contacts at the lake, tracking down owners of vehicles parked at ac-
cess points (through their license plates), or random sampling people in
the broader community.
Response rate is much more critical than the size of the sample in
getting accurate information. A good pretest will not only clarify confusing
questions but may identify factors that would reduce response rate if not
corrected. Don Dillman in Mail and Telephone Surveys: The Total Design
Method (1978) provides excellent guidance on social surveys.
Two follow-ups, including a new questionnaire each time, will typically
be required for a mail survey. Telephone surveys must include callbacks
until the targeted respondent completes the interview or refuses to do so.
Don't just interview "any adult in the household."
Response rates in general have declined but with a special local focus
like a lake, you should be able to get a 60 to 75 percent response rate. If it
falls under 50 percent, the data may be flawed since the non-respondents
are likely to be quite different than the respondents. You can find out how
different by making a special sample of the non-respondents — perhaps by
phoning non-respondents to a mail survey, or personally contacting
non-respondents to a telephone survey.
54
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CHAPTER 3: Planning: From Goals to Evaluation and Around Again
' FOCUS Group: This technique has become very common, especially in
market research. The focus group typically assembles a small group (5-10)
of people for either one or a series of meetings to discuss complex new
products or social issues. While the focus group cannot claim to be repre-
sentative, it facilitates in-depth understanding and provides the convenor
with thoughtful insights from a group of citizens. In market research and
larger population contexts, participants are often paid for their time. In a
typical lake setting, food, refreshments, and a sincere "thank you" should
be sufficient reward.
Like the Nominal Group Process, the Focus Group Technique is use-
ful at the beginning of the process, and again during the implementation
phase. As shown in Table 3-2, it cannot substitute for the quantitative data
that a social survey provides.
Table 3-2.— Strengths and weakness of four social survey research
techniques.
Generalize to
larger population
Minimum time for
completion
Cost
Cost impact of size
of geographic area
covered
Interviewer effects
Ability to deal with
complex issues
Response rate
'-<•"••:• -MAttEO :;:,
QUESTIONNAIRE
Yes
Moderate
Low
Low
Low
Moderate
Moderate
: ''':'' TElEPriONK':. ?;
•"-"iNTEfeYiiw:iv?:
Yes
Fast
Moderate
Low to
Moderate
Moderate
Low to
Moderate
Moderate to
High
i IN-PERStMSI
INTEIWIEW
Yes
Slow
High
High
High
High
Moderate to
High
FOCUS GROUP
INTERVIEW
No
Fast
Low
High
High
High
NA
Source: Barbara Burnell, Wisconsin Survey Research Laboratory, University of Wisconsin-Extension (1 998).
' Delphi Process: The Delphi technique (Delbecq, et al. 1975) is based
on the premise that any one expert (or citizen) has incomplete knowledge
and is inherently biased. Therefore, a panel of experts is expected to pro-
duce a more complete range of issues or solutions and more balanced
recommendations than a single expert.
This procedure is useful in setting research priorities, summarizing cur-
rent knowledge, and making policy recommendations for public bodies. For
instance, you could use it to design a management plan for a new reservoir.
The first stage of the process is to solicit the full range of issues,
ideas, and concerns associated with the topic. The experts (at either a
meeting or through correspondence) simply provide a "laundry list" of all
items that might be appropriate.
In the second stage, the same experts rank the list developed in Phase
I by some criterion of importance. You can use additional phases to obtain
greater specificity and consensus regarding the highest ranked items. Some
concerns will require many phases before agreement is reached.
55
-------
Managing Lakes and Reservoirs
_
..
»\*>itizens are some-
times more concerned
about how decisions are
being made than the
.decisions themselves.
_ I he needs assessment
Jis just that; it gives you a
Mist of concerns that, need
s
attention.
The results of the Final Phase are communicated to the organization
that initiated the effort.
This procedure is too complicated and expensive for most lakeshore
communities; but it does emphasize that lake organizations should get a
second opinion on major recommendations they receive from a consul-
tant or public agency.
v Other Public Involvement Methodologies: Prior to 1970
citizens had limited input in natural resource policies. Some agencies held
public hearings but they were primarily an opportunity for the agency to
tell the public what they planned to do or were already doing.
Since 1970 the major federal natural resource agencies have been
mandated to provide for public participation. As a result, a whole set of
public participation processes has evolved. Examples include the Consen-
sus Model, Key Community Contact Interviews, Futures Retreats, Citizen
Advisory Committees, Simulation Games, and Guided Tours. Kathy
Carman and Ken Keith (1994) describe 69 Community Consultation Tech-
niques in their guide for planners and facilitators in Australia. University
Extension offices and private organizational consultants can provide guid-
ance in using many of these techniques.
Citizens are sometimes more concerned about how decisions are
being made than the decisions themselves. Schmuck and Runkel (1994)
have developed a 10-item instrument (see Table 3-3) to gauge how an or-
ganization's board of directors, committee members, employees, or citizen
members feel about the process of decision-making.
Problem Identification
The needs assessment is just that; it gives you a list of concerns that need atten-
tion. Some concerns may relate to the social system; others to the ecological sys-
tem. Most lakeshore communities will have a mix of both — and both will need
attention. Problems in both systems reduce the quality of life for citizens by di-
minishing the lake as an aesthetic, economic, educational, emotional, recreational,
and spiritual resource.
A lake problem is a limitation on use. Historically, the most common prob-
lems have been associated with the lake itself: too many weeds, too much algae,
murky water, odor, or poor fishing. During the past two decades, conflicts over its
use have increased dramatically.
As the size of motors increased, so did the conflicts between motorized us-
ers and non-motorized users (canoeists, swimmers, anglers, scuba divers, and
wind surfers). And then, personal watercraft (jet skis) appeared. Personal
watercraft users can damage shallow lake areas and harass waterfowl, in addition
to polluting the air and water. But their overwhelming impact is on other people:
user conflicts are social system problems.
Another social system problem for numerous lakes is the lack of an effective
organization to manage and protect the lake. Many plans developed with excellent
professional guidance are never (or poorly) implemented because the lake manage-
ment organization was not properly structured, had too little power, lacked public
support, or its leaders were not capable of carrying out the responsibilities. To ad-
56
-------
CHAPTER 3: Planning: From Goal's to Evaluation and Around Again
Table 3-3.
—Decision-making: Storecard on the process.
THE WAY THINGS ARE
Always
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
Source: Schmuck, R.A.
4
4
4
4
4
4
4
4
4
4
and P.J.
5
5
5
5
5
5
5
5
5
5
Runkel
Never
6
6
6
6
6
6
6
6
6
6
DECISION-MAKING ATTRIBUTES
A. Decisions are made through
teamwork.
B. Facts from those who know are used
to make decisions.
C. You take a part in making decisions
that affect you.
D. You or your peers help make
decisions.
E. When decisions are made, they are
based on information that you think
is right and fair.
F. Decisions are made by those who
know most about the problem.
G. The people who make decisions that
affect you are aware of the things you
face.
H. Decisions are made in such a way
that you do not mind carrying them
out.
1. Leaders work with their peers and
people below them to make the
decision.
J. Things are organized so that you or
your peers can help make decisions.
THE WAY THINGS SHOULD BE
Always
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 994. The Handbook of Organizational Development in Schools and
3
3
3
3
3
3
3
3
3
3
Colleges, p.
4
4
4
4
4
4
4
4
4
4
285-86.
5
5
5
5
5
5
5
5
5
5
Never
6
6
6
6
6
6
6
6
6
6
dress this problem in Wisconsin, the Wisconsin Lakes Partnership has begun a
Lake Leaders Institute to enhance the leadership capacity of local lake leaders.
The process of Problem Identification is dealt with in detail in Chapter 4 —
especially problems with the physical resource.
Inventory
The third aspect of Step 2 in the planning process is to inventory the lake and the
watershed and to clarify the relationship between them. The inventory should
also include state and local regulations that apply to both. Boating regulations in
particular are becoming more common and more critical.
Start the inventory with a thorough search for records of previous studies on
the lake. Such data are useful as a historical baseline and may reduce the need for
certain new inventories. For instance, documentation of previous land use is essen-
tial for understanding the impact of recent land-use changes on water quality.
In addition to searching lake association and government files, you may want
to interview several senior citizens and retired professionals whose long-term
memory can lead you to "fugitive literature" (non-scientific, often anecdotal or
journalistic) on the lake, and whose insights can enrich discussions.
57
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Managing Lakes and Reservoirs
The type of data needed will vary with the needs and the problems. Typically,
an inventory includes information on hydrology (e.g., hydraulic resonance time),
water quality (e.g., dissolved oxygen, temperature, nutrient concentration, vegeta-
tion, transparency, hardness, and sedimentation), land use and land-use regula-
tions, fish and wildlife populations, sensitive ecological areas, and shoreland visual
quality. The remaining chapters of this book will detail how to collect such data
and how to interpret the results and understand the interrelationships.
STEP 3: Conceptualizing the
Alternatives
What We Could Do
In Step I the professional's only role is to help citizens and community leaders
think broadly about all the potential social goals that relate to their lake and en-
courage them to clarify those goals and keep them in balance.
Step 2 involves citizen monitoring, but professionals bear the primary re-
sponsibility for most of the data gathering.
In Step 3 professionals play a lead role supplemented by the ideas of citizens.
And in this step no idea should be disregarded.
Typically, interpreting the information from Step 2 will result in a series of
possible actions to protect or rehabilitate the lake. They will vary in cost. Some
will be sure bets with very predictable results. Some techniques may have unde-
sirable side effects or not produce enough change or be very expensive or too
risky. For example, the same weed problem could be attacked with dredging, win-
ter drawdown (in northern climates), herbicides, harvesting, grass carp (where le-
gal), erosion control ordinances, stream fencing, winter manure storage (in
northern climates), sedimentation traps, or benign neglect. The selection of a
technique in Step 4 should be based on the results of all the previous steps plus
affordability.
Be careful to conceptualize the full set of alternatives. Too often, both profes-
sionals and citizens fall into mental traps set by narrow training and expertise —
and inexperience. Usually, means are confused with ends. For example, many pro-
fessionals treat "reduction of phosphorus loading" as an end when it is a means
(an important one but not the only one) to the ends discussed under Step I —
Clarifying Goals.
As shown in Figure 3-2, the Ultimate Goal, at the top of the means-ends hi-
erarchy, is Sustainable Social Well-being. The 11 Primary Goals or Needs (Klessig,
1994; Klessig and Hagengruber, 1999) form the second tier of goals and also serve
as means to the Ultimate Goal above them. Below each of the Primary Goals is a
set of Sub-goals, each of which is an alternative means to that Primary Goal.
Usually several Sub-goals must be used as means to achieve the Primary Goal, but
unlike the Primary Goals, they are not all necessary conditions; choice is available.
As the pyramid spreads out to Sub-sub-goals and further down, more and more
alternative paths (different means) become available to get to the Primary Goals
and Ultimate Goal.
Figure 3-3 shows the means and ends hierarchy for a northern temperate
glacial lake suffering from winterkill of fish where one of the Primary Goals is to
use the lake for recreational fishing.
58
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CHAPTER 3: Planning: From Goals to Evaluation and Around Again
SUSTAINABLE
SOCIAL
WELL-BEING
.
Q.
O
.<_>
ID
O
U
O
Q.
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O
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Figure 3-2.—Top of the Means-Ends Hierarchy: Ultimate Goal and Primary Goals.
The Sub-goals are all alternative means to achieving the Primary Goal of rec-
reational value from this lake. Similarly, the Sub-sub-goals are alternative means to
each of the Sub-goals.
The means-ends hierarchy has no bottom. Each level becomes more specific
and eventually the detail becomes trivial. Unfortunately, both citizens and profes-
sionals frequently get trapped in one of the lower boxes in Figure 3-3. Because of
training, experience, or disposition, they have become comfortable with one
means low in the pyramid. They convert that means into an end in itself and thus,
have difficulty considering all the other pathways to the Sub-Goals, Primary Goals,
and Ultimate Goal.
How do you overcome this natural tendency to tighten the noose of famil-
iarity? Antidotes include broader training, diverse work experience, regular pro-
fessional development, and field trips to communities using other pathways up the
means-ends hierarchy.
Citizens and professionals typically start from one of the lower boxes in the
hierarchy. Entry-level jobs usually confine professionals to such a box and citizens
often have the solution in mind before they begin the planning process. Both groups
can break out of their boxes if they are encouraged to look at the big picture —
which means raising their eyes to the top of the hierarchy for the real goals and to
the sides of the hierarchy for all the various means to achieve those goals.
As shown in Figure 3-3, you can take numerous pathways (means-ends se-
quences) to the Primary Goal of Recreational Opportunity on a lake suffering
59
-------
Managing Lakes and Reservoirs
J!
o
•s
£
•o
n
n
60
-------
CHAPTER 3: Planning: From Goals to Evaluation and Around Again
from winterkill. Of course, that lake also contributes to Aesthetic Opportunity
and perhaps to Economic Opportunity, Educational Opportunity, and Spiritual
Dimension. Some of the pathways will overlap. A single means may lead to the
fulfillment of more than one end.
Summarize in writing the alternatives from Step 3, the supporting data from
Step 2, and the goals clarified in Step I and distribute them before the meeting
where your group will make the decision on what to do (Step 4).
STEP 4: Making a Formal Decision
What We Decide to Tr
The lead role played by professionals in Step 2 and Step 3 evolves to local com-
munity leaders in Step 4. The professionals' role in Step 4 is to be on tap but not
on top. In addition to preparing an attractive Executive Summary of Steps I -3, the
professional(s) will probably be asked to explain the different options and the
likely scenario that would follow with each of them. Professionals may also be
asked to explain certain relationships and predictions.
In a democratic society, however, when you're dealing with the management
of a local resource that is important to citizens in so many ways (Step I), profes-
sional resource managers must not let themselves be dragged into making specific
recommendations. A formal recommendation by a professional diminishes citizen
motivation and sense of responsibility. If something goes wrong, citizens will
blame the consulting firm or the government agency. Citizens will often ask pro-
fessionals to tell them what to do, but such a cop-out reduces citizen ownership
for their lake and their ability to make other decisions.
If citizens are to be partners in lake management, they need to be empow-
ered beyond taking Secchi disk readings. They can't be given an easy way out even
if they ask for it.
Of course, lakes within the jurisdiction of a government agency are a differ-
ent story. A government manager often relies on professionals to make the deci-
sions for a lake on government land. But even under these conditions, lake users
can be involved with some decisions.
Multiple land ownerships surround the more typical lake. Often the lake as-
sociation, lake district, or municipal board will decide to pursue more than one
action. A formal plan may have several elements, such as water level control, rec-
reational use restrictions, better shoreland zoning enforcement, vegetation har-
vesting, fish management, wetlands purchase, etc. The Model Lake Plan for a Local
Community (see Appendix 3-A) illustrates the selection of eight major options by
the members of the Lake Hale District (Klessig et al. 1994).
STEP 5: Defining Measurable
Objectives
We Need a Standard for Success
Objectives provide both the guideposts for implementation and a barometer of
success. Thus, an objective should state a quantity and the completion date, e.g.,
"Install an aeration system with 500 feet of diffusion pipe by November 1,2002."
n a democratic society,
however, when you're
dealing with the
management of a local
resource that is
important to citizens in
so many ways (Step 1),
professional resource
managers must not let
themselves be dragged
into making specific
recommendations. A
formal recommendation
by a professional
diminishes citizen
motivation and sense of
responsibility.
f citizens are to be
partners in lake
management, they need
to be empowered
beyond taking Secchi
disk readings.
61
-------
Managing Lakes and Reservoirs
T \ good plan has a
series of objectives that
rollowfrom each of the
alternatives chosen and
jjuide the implementa-
ion process for years
and perhaps decades.
[I he
he success and
sfficiency of the plan's
implementation will
depend on how well the
lead citizens and the
professionals form a
partnership that can
orchestrate the wealth
»f human resources
available.
A good plan has a series of objectives that follow from each of the alterna-
tives chosen and guide the implementation process for years and perhaps de-
cades. The Model Lake Plan for a Local Community (Klessig et al. 1994) includes 34
objectives with timelines ranging from less than one year to 27 years; it also
serves as a generic template for a report to the community (see Appendix 3-A).
Once you've formally adopted the plan (with specific objectives) and devel-
oped the implementation strategy, put all that information into an attractive doc-
ument and distribute it to all residents, local recreation and civic clubs, local
elected officials, local and regional resource management professionals, and the
media.
The document should serve as:
• A source of community pride;
• Recognition for the work of the citizens committee;
• Recognition for the professionals who worked with the community;
• A guide to implementation; and
• A way to keep the leaders of the local lake management organization
accountable.
STEP 6: Implementing the Plan
How We Put the Plan into Operation
The plan climaxes with the actual activity — the protection and restoration of
the lake. It may be getting the county board to better enforce their shoreland
zoning ordinance or it may be hiring a contractor to rebuild the dam. It may be
successfully protecting a wetland or a scenic bluff.
Implementation is the nitty-gritty work and the paperwork that goes with it.
Many activities require permits from the state water regulatory agency. And if
you're using financial assistance from agencies and other organizations, you will
probably have to write special financial proposals and progress reports.
Citizens will be almost entirely responsible for some elements; e.g., citizens
are much more effective lobbyists than professionals are. Other activities require
sophisticated engineering, limnological, fisheries, or botantical expertise.
The success and efficiency of the plan's implementation will depend on how
well the lead citizens and the professionals form a partnership that can orches-
trate the wealth of human resources available. Social capital is the term sociolo-
gists use for the good will that greases human organizations at every level. Social
capital includes the personal networks and the institutional history of coopera-
tion. Without that trust, people lose motivation and resort to bureaucratic and
legalistic processes to protect themselves.
Making a lake plan work requires physical capital (lake and watershed), finan-
cial capital (local funds, grants, loans), human resources (citizens and profession-
als), and social capital (trust). Later chapters deal with the specific limnological
expertise required by lake plans.
62
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CHAPTER 3: Planning: From Goals to Evaluation and Around Again
STEP 7: Evaluating the Results
Were We Successful?
Too frequently evaluations focus on the amount of money spent or number of
hours invested. Both these measures of effort can reward inefficiency — a project
that was more costly in terms of money and time is somehow judged to be more
successful.
You can decrease the confusion of effort and results by focusing on objec-
tives. An objective that specifies a quantity to be accomplished by a certain date is
easy to evaluate. For example: the objective of "installing an aeration .system with
500 feet of diffusion pipe by November 1,2002." In the year 2003 your report to
the annual meeting of the lake association can answer these specific questions:
• Was the aeration installed?
• How many feet of diffusion pipe were laid?
• Was the system operating before ice-up in the fall of 2002?
Some objectives are more difficult to quantify. Educating realtors or lot own-
ers regarding shoreland sensitivity and development regulations occurs over time
as a result of multiple exposures to information. A hierarchy of evaluation ques-
tions for educational objectives is shown in Table 3-4. They move from simple
measures of effort by the educator to reported knowledge gains by the target au-
dience to actual behavior changes by the audience to the impact of those behav-
ioral changes.
In addition to evaluating specific objectives, the officers of the lake manage-
ment organization (or a special committee) should take a comprehensive look at
the whole set of objectives about every five years.
.
Table 3-4.— Levels of achievement of educational objectives.
EVALUATION LEVEL
Input
Activity
Participation
Reaction
Learnings
Application
Impact
EVALUATION MEASURE
Teacher's energy investment in preparation
Event occurrence — workshop was held
How many
Post -event
Differences
Participant
people were involved?
subjective feeling about participation
between pre- and post-test of knowledge
used knowledge
Individual, business, family, or community changed as a result of
using knowledge
I n addition to evaluat- ,
ing specific objectives,
the officers of the lake
management organiza- I
tiph (or a special
committee) should take
a comprehensive look at
the whole set of
objectives about every
five years. ;
63
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Managing Lakes and Reservoirs
I __
Limnologlcal data are
most useful if collected in
e same places in the
same way over long
I;:;,;.' : ,. ..;.*; :- , , ,~,
periods of time.
STEP 8: Repeating the Process
When the Kids Grow Up, Give Them Their T&irn
The End is Not the End
No plan is static. Conditions change. Scientific understanding changes. Human val-
ues and attitudes change. Plans have to change — slowly and systematically. A plan
that is too responsive to changing demographics and political swings will fail to
provide the stable guidance that long-term management requires. A plan that is
too rigid will lose relevance and be ignored.
By the time the third general review is completed, the plan is likely to be 15
years old. If a new planning process is begun at that time, it will be completed
within 20 years of its predecessors or about one human generation time.
Continuous Data Gathering
Limnological data are most useful if collected in the same places in the same way
over long periods of time. While these data are used most intensely during Step
2, at least part of the collection regimen should be continuous. The lake associa-
tions around populated or large lakes can afford to hire professionals; some com-
munities have their own lake manager. However, in most communities citizen
volunteers perform continuous monitoring duties. These volunteers need train-
ing, record-keeping support, an occasional pep talk, and public recognition for
work that can otherwise lose its glamour after several years.
Organizational Maintenance
of Citizen Organizations
Everyone involved in a lake planning and implementation effort wants to get the
job done — wants to save the lake. But like a farmer, who is so anxious to harvest
the crops that s/he chases out to the field without greasing the equipment, com-
munity energy must be shared between the task of lake management and the
maintenance of the lake management organization.
If community leaders are too zealous, they will forget to grease their organi-
zation. They might fail to appreciate the work of the many volunteers who do ev-
erything from water quality monitoring to organizing the Fourth of July boat
parade. Sometimes zealots are so task oriented that they even publicly criticize
citizens and elected officials for being "lazy" or "apathetic." Zealots often end up
trying to do everything themselves because they have alienated everybody else.
And, of course, they can't do everything very long. Unless a balanced leadership
develops the lake management organization may actually dissolve.
Although zealots get the community focused on a lake problem, they tend to
dominate a new organization. Sometimes they mellow with experience; but too
often, they have to be replaced as an organization matures.
The older an organization is the more likely it will suffer from the opposite
problem — lack of task orientation. It becomes too focused on having a good
time with old friends and keeping everybody happy. The spring picnic, the Fourth
64
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CHAPTER 3: Planning: From Goals to Evaluation and Around Again
of July boat parade, and the fall dinner become the core annual activities. Mainte-
nance of the organization becomes an end in itself. Leaders tend to be extroverts
who love to socialize. These leaders avoid conflict internally and externally and
thus avoid making tough decisions about the lake.
The ideal lake management organization has a blend of leaders — some fo-
cused on the task of managing the lake and some focused on the maintenance of
the organization. Such a balanced leadership team can both accomplish the plan's
objectives and keep the organization strong for the long term. Best of all, under
such a leadership team citizens can enjoy working with each other and be proud
of their mutual accomplishments.
The final ingredient for the successful long-term lake management organiza-
tion is new blood. Lake management organizations often have a very high percent-
age of retired people who, of course, provide a wealth of experience, free time,
and funds. But use them wisely; encourage them to transfer their wisdom and in-
stitutional memory to the next generation. Lake management organizations
should consciously and slowly turn over the organization to the next generation
as the planning process is repeated.
References
Burnell, B. 1998. Strengths and weakness of major research variations. Unpubl.
instructional material, Wisconsin Survey Research Laboratory, University of
Wisconsin Extension, Madison.
Carman, K. and K. Keith. 1994.69 Community Consultation Techniques. Queensland
Department of Primary Industries, Brisbane, Queensland, Australia.
Delbecq, A.I., A.H. VanDeVer, and D.H. Gustafson. 1975. Group Techniques for
Program Planning: A Guide to Nominal Group and Delphi Processes. Scott,
Forstman.and Co., Glenview, IL.
Dillman, D. 1978. Mail and Telephone Surveys: The Total Design Method. Wiley, New
York.
Klessig, L.L. 1973. Recreational Property Owners and Their Institutional Alternatives
for Resource Protection. University of Wisconsin, Madison.
. 1994. Community and Societal Sustainability: The Anti-Priority Hypothesis.
R. Wolensky and E. Miller, eds. Proc. Small Cities and Regional Community
Conference. Vol. I I. University of Wisconsin, Stevens Point.
Klessig, L.L.and J. Hagengruber, 1999. Eleven necessary conditions for societal
sustainability.J. Human Values 5(1): 33-52.
Klessig, L.L., N.W. Bouwes, and D.A. Yanggen. 1983. The Lake In Your Community.
G3216. University of Wisconsin Extension, Madison.
Klessig, L.L, B. Sorge, R. Korth, M. Dresen, and J. Bode. 1994. A Model Lake Plan for a
Local Community. G3606. University of Wisconsin Extension, Madison.
Leopold, A. 1949. A Sand County Almanac. Oxford University Press, Oxford, U.K.
Roser, N.W. and W.J. Serow. 1984. Introduction to Applied Demographics: Data
Sources and Estimation Techniques. Sage Univ. Paper 39. Sage Publications,
Beverly Hills, CA.
Schmuck, R.A. and RJ. Runkel. 1994. The Handbook of Organizational Development
in School and Colleges. Waveland Press, Prospect Heights, IL.
.
I he ideal lake manage-
ment organization has a
blend of leaders — some
focused on the task of
managing the lake and \
some focused on the <
maintenance of the
organization. i
65
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Managing Lakes and Reservoirs
Shifferd, P. and S. Palmer. 1997. Being at the Lake: Problems of Organization in a
Vacation Community. Report prepared at Northland College, Ashland, Wl, for
the Wisconsin Department of Natural Resources, Madison.
Technical Committee of the Water Resource Centers of the Western States. 1974.
Water Resource and Planning, Social Goals, and Indicators: Methodological
Development and Empirical Test. Utah State University, Logan.
U.S. Environmental Protection Agency. 1995. Watershed Protection: A Project Focus.
EPA 841 -R-95-003. Off. Wetlands, Oceans, Watersheds, Washington, DC.
66
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APPENDIX 3-A
sag, Buzz Soree,.Robert Kortfi, Michael Dresen, Jeff Bode
12 CodPentth'?, Extension.
, t »«»sSffl*as^v'*^«»j«*MB«6«««;ss!
'^KB^SfffJem Point'. '.*• College of Natural Resources
^••^'^^^^^^f^^^^^^il^^j:i^gS,y,^,S^tmii^t,^
\ Jswrwuef Water Resources.Mgnagejtnent,
Luke
, ,;>f:^r^
; • :«f. , •/:/---i^w/ ^
-------
Contents
IMGE . -- .-—
! ii Preface —-
?z/V Lake Hale—A historical preface
\ 1 Why we care about the future—our goals for
1 2 Assessing needs and identifymgpwb^ms'^
* Concerns of district-members.-
i Public users
i Public access
• 6
s£3iss,fg£S
Watershed
Fish """" ' -
i Wildlife
: regulations
it and natural beauty
• options to making decisions
)o nothing
jfSon£2r-^-Dredge channels in Lily Bay
Option 3—Chemically treat excess plants
Option 4—Harvest excess plants
Option ^^-Control >sdien specie's
Option (^eReduce ^rictd|j.|ral runoff
Option /ftr^-educe Jo.n^$ction site erosion
litary survey
^_Opaoa^4-^urch^;ecQlogically and aesthetically sensitive land
Option?;ilQ^^^BfiyJor stronger enforcement of county zoning laws
_jOption :Kp^0peraf&=a_water safety patrol
Optiori'Jifr-—ConoT^ ~"~ •=^-—-- 1—-=
^••:
intensive educational effpkt
-------
Preface
This publication was written for people who live
on or use lakes, and for community officials
involved in lake management. It sets forth a model
management plan for the fictitious Lake Hale in
Phantom County.
The Lake Hale model is designed to help commu-
nities care for local lakes in three ways:
1. By explaining the types of information
needed to make decisions at the local level.
2. By offering a format for summarizing infor-
mation and debating alternatives.
3. By furnishing an example of community
commitment to a lake.
In each case, the model should be modified to fit
the characteristics of the individual lake and the
expectations of local residents and lake users. Keep
in mind that Lake Hale is a fictitious lake with
features commonly found in small to moderate-
sized kettle lakes. (Large lakes and impoundments
have substantially different characteristics.)
Some lake planning efforts have yielded more
detailed reports than the example provided here.
In fact, formal and technical documents may
sometimes be necessary to meet external needs
such as the Department of Natural Resources
(DNR) Area-wide "Water Quality Management
Plans. In those cases, this model might provide a
format for summarizing larger reports to distribute
to community residents.
Many Wisconsin communities have received or
are considering applying for a DNR Planning
Grant. The information found in this model
directly pertains to both the loan application
process and the final report required under the
grant.
The lake plan you generate will set the tone for
management efforts on your lake for the next
generation. You should review it every few years to
determine if you are meeting your objectives on
schedule and to re-evaluate your long-term goals.
If you need assistance, call your DNR district
inland lake coordinator or University of
Wisconsin—Extension community resource devel-
opment agent. (Some of these people helped
produce this model by serving as reviewers.) To
share ideas with other lake organizations and
explore common interests, join the Wisconsin
Association of Lakes.
Good luck in this important effort.
LowellKlessig, University ofWisconsin—Extension/University of Wisconsin—Stevens Point
Buzz Sorge, Wisconsin Department of Natural Resources
Robert Korth, University ofWisconsin—Extension/University ofWisconsin—Stevens Point
Michael Dresen, University of Wisconsin-Extension/University ofWisconsin—Stevens Point
Jeff Bode, Wisconsin Department of Natural Resources
-------
Ill
Lake Hale—a historical preface
The last glacier to visit Wisconsin created Lake
Hale about 10,000 years ago. The glacier left an
assortment of soil, boulders, stones and other
debris as it retreated north. Occasionally, chunks
of ice broke off and were buried in the glacial
remains. When one large chunk melted, Lake
Hale was born.
After several thousand years, small bands of
Chippewa set up a summer camp at the site of the
present day county park. Much later, in the
1870s, die region was extensively logged for pine.
Areas that escaped the subsequent forest fires were
logged again for hemlock and hardwoods. A small
sawmill was built on the lakeshore between Sunset
Point and Hale Creek in the early part of the 20th
century. No efforts were made to protect the lake
from sawdust or from the serious erosion follow-
ing the forest fires.
Agricultural practices brought about additional
sedimentation and nutrient enrichment of the
lake. Wheat farming dominated in the 1880s,
with a gradual switch to dairy farming by 1940,
but sandy soils and harsh climate proved inhos-
pitable to farming. Eight Norwegian farmers had
established homesteads around the lake by 1900;
by 1960, only four families remained. These
farms, as well as the resort on Sunset Point, were
subdivided for cottage sites in the 1960s and
1970s. The last and largest farm on the lake was
owned by the Olson family; in 1989, it was devel-
oped as die Northern Heights subdivision.
The first cottages were built on the lake in the
1950s. Many were concentrated right on die lake-
front—where impacts on die lake are most direct.
In the 1970s and 1980s, cottages were converted
to winterized homes.
A lake association was organized in 1963 after a
local resident was killed in a water skiing accident.
The association persuaded the town board to
establish a one-way circular skiing direction and
prohibit water skiing in the north lobe.
Because of increasing concern about excessive
plant growth and the potential negative impact of
backlot development near the lake, a lake district
was established by petition to the town board in
1985- Since its formation, the district has received
three planning grants from the Wisconsin
Department of Natural Resources. The district
contracted for aquatic plant harvesting in 1987
and 1989-91.
Overall, land use in the watershed (die land that
drains toward the lake) has changed dramatically
in die past 130 years. These changes have
damaged die lake. This plan, and recent aquatic
plant harvesting efforts, are designed to help cope
with diose changes and protect the lake from
further degradation.
-------
Why we care about the future-
our goals for the Lake Hale community
Lake Hale and the creatures that live in and
around it form an integral part of our community.
We want the lake to be healthy so we can enjoy its
natural beauty and use it for recreational activities.
But more than that, we feel a sense of steward-
ship—a responsibility to protect and restore the
integrity of the lake's ecosystem.
Our ultimate goal is to perpetuate the wildlife,
natural beauty and recreational activities we enjoy
for future generations of lake users. To meet that
goal, we realize that we must develop a set of
ethics for our interactions with the lake. Unless we
are willing to limit the type and location of shore-
line buildings we construct, the amount of shore-
line we clear, the size of our boats and motors and
the way we use them, the lake will no longer be
the source of the natural beauty and recreational
activities we enjoy today.
Specifically, we have three goals:
1. To maintain and restore the environmental
integrity of the lake ecosystem.
2. To protect aesthetic opportunities for residents
and visitors by preserving scenic lake views.
3. To maintain on-the-water recreational
opportunities by discouraging behavior that
interferes with the activities of other users.
-------
Assessing needs and identifying problems
Concerns of lake district members
As part of the 1989 annual meeting, Jennifer
Bates, our county Extension community resource
development agent, conducted a "nominal group
process" that rank-ordered the major concerns of
lakeshore property owners. The concerns were:
1. too much noise from boats and neighbors
2. too many aquatic plants
3. crowding and lack of boating safety on
weekends
4. poor fishing
5. water quality degradation
6. unattractive shoreline structures
7. litter on the lake (summer and winter)
8. harassment of waterfowl.
We included these concerns in a standard ques-
tionnaire which was sent to each family owning or
renting property within the district. The newslet-
ter carried a reminder to complete the question-
naire, and postcard reminders were sent to each
address. One hundred of the 150 families
responded. The information in figures 1-5 was
obtained from diat survey.
Most members of the lake district are more than
50 years old and are full-time residents (outnum-
bering seasonal residents). Of those still working, a
large percentage commute to the Twin Cities.
It is clear that Lake Male's beauty is what attracts
district members; they enjoy the lake primarily for
its aesthetic value and fishing. But district
members also use the lake for motorized activities
that often conflict with other expressed expecta-
tions. The concerns of district members reflect the
increased use of the lake, as well as concern for
water quality. Loss of natural vegetation on the
shoreline and too much vegetation in the water are
other major concerns.
FIGURE 1. Age of head of
household.
| 20-29
\30-39
\40-49
50-59
\60-69
\70-79
80+
FIGURE 2. Residency and
employment status.
m Year-round retired
^ Year-roundcommuter toTwin Cities
U Works locally year-round
[fl Seasonal retired
H Takes seasonal work elsewhere
FIGURE 3. Principal reason for
purchasing property.
^ Water recreation
^ Investment
!|| Natural beauty/solitude
Bl Place to entertain
-------
Additional information on the feelings, activities
and characteristics of members of the Lake Hale
District can be found in the report entitled "Lake
Hale District Membership Survey." That report is
available from Paul O'Malley, our secretary, and
at the public library in Phantom City.
Public users
We hired Horace Billings, a sociologist from
the University of Wisconsin—Superior to help
determine the activities and preferences of
people who use the public boat ramp, the
public beach, the trails, the campground and
the picnic area at the Lake Hale County Park.
The preferences of people who stopped at the
State Highway 762 overlook were also
included in the study.
Billings devised a procedure to sample users at
each public facility on the lake. He modified
the questionnaire we used for our membership
survey and hired college students to interview
users on specific weekdays, weekends and
holidays.
We obtained a full report on each of the types of
users, how long they used the lake, and their atti-
tudes about their experiences. (The information is
43%
FIGURE 4. Primary water
recreation activities.
27%
FIGURE 5. Most serious problem
relating to Lake Hale.
| Fishing
I Swimming/
diving
I Motorized
boating
\ Jet skiing
Water skiing
Canoeing!
rowing
Sailing!
windsurfing
\Noise
| Weeds/algae
| Crowding/
boating conflicts
iPoor fishing
I Unattractive
shoreline
Litter
Harassment of
wildlife
Water level
-------
A model lake plan for a local community
available in the "Lake Hale Public User Study.")
Some summary graphs that combine all public
users are provided in figures 6-10.
Lisa Manley volunteered to coordinate the count-
ing of public users according to a schedule devel-
oped by Horace Billings. She enlisted the help of
lifeguards at the county beach, who provided
park, beach-user, pier fishing and boating counts.
Unfortunately, the summer of 1992 was very
cold, which reduced the swimming counts by
approximately 50% and may have reduced the
number of other users as well.
Between 3 to 5 p.m. on an average summer week-
day, 107 people were at the park (76 of whom
were using the beach), 9 boats were on the water,
6 people were fishing from the public pier, and 28
people stopped at the overlook on Highway 762.
On the weekend, the numbers jumped to 229
people in the park with 135 using the beach, 24
boats on the water, 12 people on the public fish-
ing pier, and 44 people at the overlook.
Bud Langley conducted monthly fishing counts
on Saturdays from 7 to 9 a.m. Angler numbers
were greatest on Saturday mornings in December
(175), January (118), and May (62).
With the help of some students who did several
all-day counts, Horace calculated the following
annual estimates:
Park users
Motorized boaters
Non-motorized boaters
Overlook users
Anglers—all types
Total users
19,000*
2,700
1,000
7,000
5.200
34,900
*Beach users accounted for 9,000 of this total.
Public access
The ramp at the County Park has parking spaces
for 17 vehicles and trailers. Under the new policy
for boat access, Lake Hale possesses 387 acres of
open water. (Those parts of Shelter Bay and Lily
Bay with emergent vegetation visible from an
47%
37%
15%
35%
FIGURE 6. Age of group leader.
FIGURE 7. Origin in miles from
Lake Hale.
• 10-29
• 20-29
• 30-39
B 40-49
50-59
60-69
70-79
80+
10-49
50-199
200+
FIGURE 8. Reason for visiting
Lake Hale.
| Water recreation
B Investment
Uf Natural beauty/solitude
III Place to entertain
-------
Assessing needs dr identifying problems
TABLE 1. Population levels and rates of change, 1980-1990.
Town of Meadowview
Phantom City
County of Phantom
Change Change Change
1970 pop since 1960 1980 pop since 1970 1990 pop since 1980
• 576 +6%
I
I 2817 +2%
I
27,002 +4%
aerial photo are not counted.) The Department of
Natural Resources codes indicate that a lake
affords reasonable public boat access if it main-
tains one parking space for each 20 to 30 acres of
open water. The current boating access is more
than adequate under the new code.
Additional public access is provided at the
Highway 762 overlook and at the county park by
the 500-foot beach, 30-unit campground, fishing
pier, picnic area and hiking trails.
Population changes
Based on population data that Jennifer Bates
(UW—Extension) obtained, the farm population
of the Town of Meadowview and Phantom
County continues to decline. However, the overall
population has grown consistently for three
decades. As shown in table 1, 1980—90 exhibited
the fastest growth. The new freeway to the Twin
Cities has increased both residential development
and public use of the lake. Both pressures are
likely to increase.
41%
33%
27%
FIGURE 9. Primary water
recreation activities.
| Fishing
• Swimming/
\ diving
\ Motorized
boating
\ Water skiing
FIGURE 1O. Most serious
problem relating to Lake Hale.
\Jetskiing
I Canoeing/rowing
windsurfing
\ Noise
Weeds/algae
| Crowding/
' boating conflicts
I Poor fishing
Unattractive
shoreline
Litter
Harassment of
wildlife
Water level
-------
6
What do we know about the lake? An inventory
Water cycle
The lake's official size is 413 acres according to
the Wisconsin Lakes bulletin. The watershed that
drains to Lake Hale is 3,054 acres. Hale Creek
drains a large part of the watershed to the north
and east of the lake into Lily Bay. Small, intermit-
tent streams drain the other areas of the water-
shed. Groundwater inflow was measured by
Dartmouth Environmental Consultants as part of
their water quality study. By putting gauges on
the inlet creek and the outflowing river, and
adjusting for precipitation and evaporation, they
concluded that over 30% of the water entering
the lake comes through the ground via springs.
On average, water entering the lake remains
about two years before it exits through the
Hale River.
Most of the north lobe is less than 10 feet deep.
The south lobe is much deeper, with only a
narrow band of shallow water (littoral zone)
along the shore as can be seen on the hydro-
graphic map (fig. 11). The maximum depth is 62
feet; the average depth is 14 feet.
A summary of Lake Hale's
physical characteristics is
presented in table 2.
Most of the
bottom sedi-
ments in the
north lobe
are decayed
-• : plant
remains, or
muck. Muck is also
found in the
center of the
south lobe
surrounded
by sandy
beaches and
a few rocky
areas.
TABLE 2. Lake Halle's physical
characteristics.
. . 3054 acres
""."5782" acre-
undwater . ,
reek . . . . 35«/o
et es.it:
a * » -W_,
. . .9%
water „
jj'iver r, . s " .
ation . . ^ . 16%
f f/ow = 3 cubic ft
^-«^^*
quality
A summary of our water quality studies and
monitoring is presented in this section.
Additional detail can be found in the consultant's
reports on "Lake Hale Water Quality" and the
DNR reports of Kathie Jansen's volunteer moni-
toring efforts. Understanding Lake Data (G3582),
a more detailed explanation of lake water quality
information, is available at the UW—Extension
office.
DISSOLVED OXYGEN. When the amount of
oxygen in the water drops below four parts per
million, some fish species are stressed or killed.
Lake Hale has not experienced lake-wide fish
kills. Oxygen levels were measured in 1992 and at
several earlier dates as shown in table 3.
In late winter, oxygen becomes depleted in
Shelter Bay and possibly other parts of the north
-------
FIGURE 11. Hydrographic map of Lake Hale.
Lakeview Bluffs
VEGETATION KEY . BOTTOM KEY
T submergent plants Mk muck
J. emergent plants Sd 'sand
floating plants (lily) Gr gravel
tpvr steep bank
-------
8
A model lake plan for a local community
TABLE 3. Dissolved oxygen in parts per million (ppm).*
Year
1963
1981
i
1992
J -fc»-
Date
Jan 4
i
Mar 2
I
Jan 2
Mar 4
1
May 22
li
June 20
N
July 31
^ n
fe
Septl
m F
mglliter
Organization
\
DNR
'
DNR
4 (
i ii
Consultant
i I'
F
Consultant „
I i
*
*( {'
» !
* |
i i 4
^
f '
Self-help monitor
! ,
r
1 f
Self-help monitor
i [ ~ i
• i ili
•BI | ™ | f* ira
M
ingu | fl
m r ifl™
Ill^ll J 1
Self-help monitor
i I*
Self-*
1
*
\ i H *>
f MUI* 1
i
ielp monitor
t ra
, i „ ,.,
;. J
Location
i ^, '
Mid south, Kobe
i >• u i « •*-»», mf
Mid south lobe
Shelter Bay
' * „ W ^ S * " s!W
Mid south lobe
* Shelter Bay
Mid south lobe "
' Shelter Bay
- *
Mid south lobe"
Mid south lobe
Mid south lobe
i- • Mid south lobe
Mid south lobe
^nyfy T *Y^ *^ ^
,• Mid^south lobe.
^" w" in *"(?
* Mid south lobe
\ f W^^'t't^t1 3ftS*S J^Hd
* Mid sojithjcfee^^
L"W * IM&MfaM *
Depth
4 ft.
4 ft
4ft.
! ' °$t*"-
4ft.
4 ft.
E
4«. w
4ft.
4ft.
40ft.
4ft.
"40 ft.
•& *
4ft.
*s
40ft,
r
** i M "S **'
40 fte
i
DO level
9
* wTj i" ^
,8
1
**" ' r i, rf i
!P
2
"i(
"0.5
V
9
9
* nrt-
v, ^A
9
"1* ]:*
8
f f
4,
P- J* M«*-
**
1* i"*®»*4 *"
1
"
1
' I
> i
1
•t
i r 'll
Ji
j
r 1
i -fl
' a
a
i
i
-Si
!! 1
i
d
* "1
. «J|
"™ ^ W'*^
lobe. While oxygen levels are;adequate for our
present fishery, the lack of summertime oxygen in
the hypolimnion (below 25 feet) is a critical indi-
cator that water quality has gradually deterio-
rated. Cisco, a fish that needs cold,
deep water to survive, has not
inhabited Lake Hale since 1970. As
oxygen levels continue to decrease,
phosphorus (an important nutrient
for algae growth) in the sediments
will become available for algae
blooms in fall. When oxygen is
present in the water, phosphorus is
less soluble and remains in the sedi-
ment.
TEMPERATURE. With encouragement
and training from Daryl Roberts
(DNR), our self-help monitoring
volunteer Kathie Jansen has taken
temperature profiles of the lake at
different depths. The numbers in
table 4 show that the lake stratified into thermal
layers from about the middle of June until
October. During that time the water did not mix
(turn over).
TABLE 4. Temperature (in degrees F) profile of Lake Hale
(south lobe) in 1992.
-------
An inventory
As expected, the lake had the same temperature
from top to bottom as it mixed in mid-April
when the ice melted, and again in mid-November
just before the ice developed.
NUTRIENTS. The lake possesses moderate levels of
phosphorus. Dartmouth Environmental
Consultants, under their first contract in 1991,
measured phosphorus levels at turnover and
found 20 micrograms per liter in spring and 28
micrograms per liter in fall. These phosphorus
levels will produce some algae, but are not likely
to yield nuisance blooms of blue-green algae.
However, if summertime oxygen loss in deep
waters becomes more pronounced, the sediments
will release more phosphorus and fall algae
blooms can be expected to increase. If phospho-
rus levels increased beyond 30 micrograms per
liter, Lake Hale would experience regular algae
blooms.
Limnologists (scientists who study freshwater life
and phenomena) use a number of indicators to
classify lakes according to their nutrient richness,
or level of eutrophication. On a trophic status
index, Lake Hale was oligotrophic (nutrient poor)
in 1850 before lumbering, farming and home
building occurred around the lake. Now it is
mesotrophic, or generally midway along the range
as shown in table 5. This means that Lake Hale is
healthy overall, but that phosphorus, which
entered the lake through soil erosion, has
burdened the lake with excess nutrients. Further
nutrient enrichment from the watershed will trig-
ger a release of phosphorus from the lake bottom
and the lake will become eutrophic.
Dartmouth Environmental Consultants measured
total nitrogen at 250 micrograms per liter. This is
within the normal range and should not stimulate
algae growth. However, nitrogen—from septic
systems, lawns and agricultural practices in the
watershed—is very soluble and can fertilize
rooted aquatic plants, leading to excess vegeta-
tion. Nitrogen availability might also encourage
the spread of Eurasian water milfoil, an exotic
invader.
TRANSPARENCY. The Secchi disc measures water
clarity by gauging the amount of algae in the
water. Turbidity from soil erosion or a tan color
from decaying vegetation also affect Secchi disc
readings. Lake Hale has a slight tea color from
natural tannic acids that drain from the wetland
along Hale Creek. Art Belder, our first self-help
monitor, took Secchi disc readings for four years.
After he moved, Kathie Jansen continued the
effort. The measurements Art and Kathie
collected show a slight, but inconclusive, reduc-
tion in transparency (fig. 12).
TABLE 5. Trophic classification of Wisconsin lakes.
Trophic Total
Class phosphorus
(ug/I)
Chlorophyll
Secchi
Disc
(ft)
Oligotrophic
i Mesotrophic
Eutrophic
FIGURE 12. Annual average
transparency.
1987 1988 1989 1990 1991 1992
-------
10
A model lake plan for a local community
VEGETATION. Excess rooted aquatic vegetation
(macrophytes or weeds) currently appears to be a
more serious problem than algae. According to
the consultant's macrophyte survey, the most
dense growth is concentrated In the north lobe.
Eurasian water milfoil has become established
south of the boat ramp along the east shore of the
south lobe and around Sunset Point. Pond weeds
are the primary species. Lily pads dominate in
Lily Bay.
Aquatic plants are measured by harvesting all die
plants in a square meter and weighing them after
they have been dried. Our consultants found that
biomass per square meter (approximately 11
square feet) was 250 grams in Lily Bay, 215 grams
around Nordieast Island, and 180 grams in die
area around Shelter Bay Island, while the average
for the south lobe was only 80 grams dry weight
(454 grams = 1 pound).
Dense growths of coontail occupy several loca-
tions in the north lobe. They become a nuisance
by early August and hamper fishing. But aggres-
sive Eurasian water milfoil is likely to pose the
greatest control challenge. Daryl Roberts from
the DNR office in Eau Claire will advise us on
how to keep milfoil in check as part of an overall
aquatic plant management strategy.
HARDNESS. Lake Hale is not susceptible to
damage from acid rain. The surrounding soils
contain enough limestone and dolomite to buffer
acidic precipitation. Measurements made by the
environmental consultants in 1991 indicate an
average hardness of 82 ppm with a dip following
spring runoff.
SEDIMENTATION. Dartmouth Environmental
Consultants took a 5-foot sediment core from the
deep hole in the south lobe to determine whether
water quality had deteriorated over the last 250
years. (The sediment core measures the rate of
sedimentation over time.) The sample indicated
diat water quality steadily declined from the
1870s into the 1940s. During those years, the
watershed was logged and then farmed. Water
quality has declined at a much more rapid rate
since the 1940s because of the watershed's inten-
sive agricultural use and real estate development
along the shorelands.
Watershed
The boundary of the watershed is shown in figure
13, prepared by Ted Walinski of the County Land
Conservation Department. Lake Hale drains
about 3,000 acres of land; the watershed to lake
area ratio is thus about 7:1. The larger the ratio,
the more the watershed will have an impact on
the lake through nutrient, pesticide and soil
runoff. (Impoundment ratios usually average
more than 100:1.) A land use survey was
conducted by our original Land Use Committee
with advice from Ted, using the protocol
provided by Jennifer Bates.
Almost half (1,380 acres) of die watershed is used
for agriculture, although none of die original
shoreline farms still operate. The shoreline areas
have been converted to lots. Residential areas,
woodlands and wedands each contribute over
500 acres to the total land use. The overlook and
county park occupy 66 acres; the filling station,
restaurant and video store cover 10 acres at the
intersection of Highway 762 and the freeway.
In their land use report, the committee warned
that backlot development was beginning. The
report stated that several large areas of the water-
shed could potentially be developed with a
common access (funnel) to the lake. Large
numbers of homeowners without lake frontage
would be able to dock boats and use a single
riparian lot for lake access. Land use in 1991 is
shown in figure 13 and summarized in table 6.
TABLE 6. Land use in the watershed.
f Agricultural 1380 (
'"';:; Forestry 555 (
"Commercial/industrial
****'*• •' * - rf^4,s^L^^&i^ikii^Kyi>^~^~-^±~'^'^ vv ... • •'*•
i^;f Institutional ..... """ 66 &%)"'
issp^^f^^ife^
" '
'conservancy ' 502 M6%1
-------
An inventory
11
FIGURE 13. Land use within Lake Male's watershed.
Agricultural
Wetland/Conservancy
Forestry.-
House
institutional
Commercial/Industrial
-------
12
A model lake flan for a local community
Fish
The local DNR fish manager, Betsy Olson, has
met with us periodically and presented reports at
the annual meeting. Betsy is concerned about
excess vegetation which allows panfish to evade
predators and overpopulate the lake. Increased
fishing pressure on predator fish like bass and
northern may also exacerbate the trend toward
overpopulation of certain species. She prepared a
comprehensive report for us to use in developing
this plan.
The native fishery for our lake consists of large-
mouth bass, northern pike, cisco, black crappie,
bluegill, pumpkinseed, perch, white sucker, and
an assortment of forage fish (minnows). Walleye,
muskie and lake trout were planted at various
TABLE 7. Lake Hale fingerling
stocking schedule.
Walleye Muskie
18,000
20,OOO
10,000
20,000
20,000
10,OOO
800
600
1,000
80O
500
8OO
times. Bluegills and pumpkinseed use Shelter Bay
as the primary spawning site, while northerns
spawn in the the shallows and wetlands behind
Northeast Island. Muskie spawn later and are
effectively preyed upon by the northern fry.
Walleye do not reproduce very well because the
lake has few rocky areas. Walleye and muskie are
planted biennially as shown in table 7. Our
Fisheries Committee (Herb Latman, Albert Nice
and Bo Hintz) assists the DNR with stocking and
shocking activities.
Stocking rates for walleye range up to 50 finger-
lings per acre. Muskie rates are 1 to 2 fish per
acre on an every-other-year basis.
The fish census (table 8) taken along the shore-
line in 1975, 1983 and 1990 indicated generally
healthy numbers and mixes of year classes, but
showed reduced panfish size. Betsy Olson noticed
that the fish were much denser along the shore-
lines where natural vegetation was retained. Few
fish were found in front of homes where the
owner had "cleaned up" the shoreline.
Wildlife
Two active eagles' nests are located.in other parts
of the town and the occupants regularly visit
Lake Hale. Osprey visits are less common. Until
I960, the lake supported a family of loons, but
these birds now appear only during migration
and occasionally during the summer. Lowell
North, our local Loon Ranger, participates in the
TABLE 8. Fish shocking census.
Largemouf h bass | 38
iiSfeli
16
ii |jiifc«? JL--- ",rf ••- ^^^ .- 'IK:, I!" "ail:
;T "Iv'i" I'lSilllr,!',' .iiu !', ,N,,'in ^
J'Vilil|i.Mii''. 'J'SFi
-------
An inventory
13
regional Loon Watch program of the Sigurd
Olson Environmental Institute at Northland
College in Ashland. He believes that disturbance
from boat traffic is the reason loons no longer
nest on the lake.
Frog numbers seem to be down sharply; acid rain
or another atmospheric pollutant is the suspected
reason. Other amphibians are experiencing
similar downtrends.
Boating regulations
The Town of Meadowview has prohibited power-
boating at speeds greater than "slow-no-wake" in
Lily Bay and behind both Northeast Island and
Shelter Bay Island. Water skiing is not allowed in
the north lobe and must follow a clockwise direc-
tion in the south lobe. The level of compliance
with the regulations varies. Jennifer Bates helped
the lake district and town prepare an application
for the placement permit and state cost-sharing of
the buoys. Neither the lake district nor the town
has a patrol boat.
Shore development and
natural beauty
Most of us bought property here so we could
enjoy Lake Hale's cool blue beauty. But some of
our activities have tarnished and threaten to
further reduce the area's attractiveness. During its
survey, our Land Use Committee noted areas that
were especially beautiful or ecologically fragile
and thus warranted special protection.
The committee suggested that areas shown in
table 9 and figure 14 be considered for special
protection. It also noted spots that looked unap-
pealing and needed a face lift. Duane Peters, the
county code (zoning) administrator, assisted in
these efforts.
The Land Use Committee also wanted to register
the group's concern about practices that large
numbers of residents currently engage in that
diminish the lake's beauty (shown in table 10).
Many of these practices have been prohibited
since 1970 under the Phantom County
Shoreland Zoning Ordinance.
-------
14
A model lake plan for a local community
TABLE 9. Areas of special beauty or ecological significance.
SUNSET EOINT PARK
i
1 . '
IOUTH OF HALE RIVER
j
i CREEKMARSH
aoEWEW BLUFFS
SHELTER BAY ISLAND
Distance from water Acres Current ownership
Narrow peninsula
i S * .
On the shore
Surrounded by water
| ) «l I '
Surrounded by water
1 Common property of people who purchased
"" *fif i fyhe old resort parcels J
40 ^County land-—unmanagedandusedby "
*"off-road'reci-eation vehicles
1 T IU «fS »«&*
Extends 3 miles upstream 200
« , n ««, , ,,-ij
Off-shore with single 100
lake-access lot
Areafarmers
Dream Estates—land development company
from St. Paul
Northern tieights Subdivision Assn.
7
S <• (» _ .
16 _ yiwVe Knight from Minneapolis
TABLE 10. Practices that diminish the beauty of Lake Hale.
Practice
Estimated
number
Constructing buildings closer
than 75 feet from shore
Improving nonconforming structures
Within the 75-foot setback more than 50%
Placing septic fields closer than 50 feet from
shore
Clearing more than 30% of each
'100ft. (first 35 feet from water)
Painting buildings bright colors so that they
'are highly visible from or across the lake
i,r ' 'iii.ii ,ii "iPiriir1 its:1 "nil ifii.i wiLvuiiiiiitiiPiiiiii'iiriii 4 « \%
-------
An inventory
15
FIGURE 14. Sensitive areas in the water and on the land.
r- .r
**
'*
Wetlands that- -
filter water
Too shallow
for boating
'8
pi
Shallow water, generally less
than 5 feet
H
N i
f-i
Lakeview Bluffs wetlands proiSd. " ' £—' ^- *'
,„.- scenic backdrop ing wildlife habi- ~\5
tat and natural
£KK * I * -, ^8t Bf i,-^ *
scenery
Highly erodible land
Areas of special natural beauty * |
Navigation buoys-slow no wake
4Mr Bluegill spawning
Northern spawning
Hale River
-------
16
From considering options to making decisions
The following options were developed by Jerry
Van Syke of Environmental Consultants after a
series of meetings with the board, Jennifer Bates
(UW-Extension), Daryl Roberts (DNR inland
lake coordinator), Duane Peters (county code
administrator) and Ted Walinski (County Land
Conservation Department). The Board of
Commissioners presented their recommendations
to the Lake Hale District at a special meeting on
April 3, 1993. The Lake Hale Plan consists of
the options adopted at that meeting.
OPHCOSUL
Do nothing.
This alternative does not require spending money
and, in the short run, allows us to continue to
enjoy the lake rather than worry about the future.
Few people voiced this opinion, and the option
was not seriously debated.
OPTION!:
Dredge channels in Lily Bay.
Dredging channels would remove about 20,000
cubic yards of material at a cost of $4 to $10 per
yard. While fishery habitat and boat access would
be improved, the project could damage the native
plant community if it was not carefully designed.
A disposal area and permits would be required.
Vote to adopt: 33 yes, 106 no.
OPTIONS
Chemically treat excess plants.
With a permit from the Department of Natural
Resources (Aquatic Plant Management), the
district could hire a certified applicator and treat
areas within 150 feet of shore. Application cost
would be about $225/acre per summer.
Vote to adopt: 47yes, 91 no.
OPTION 4
Harvest excess plants.
The excess vegetation in the north lobe could be
harvested by a contractor who would charge $100
an hour, or we could purchase equipment and do
the work ourselves. The Wisconsin Waterways
Commission shares half the cost of equipment
purchases. The estimated price of a 5-foot
harvester plus conveying equipment is about
$40,000. The cost of cutting 100 acres between
June 20 and August 20 will run to about $10,000
per season. This option requires a feasibility
analysis.
A vegetation management strategy has been
prepared with assistance from Daryl Roberts of
the DNR. The vegetation management strategy
does not include herbicides. It focuses on physical
methods to remove plant material and on better
protection for native plant communities. It has a
lower potential for controversy and divisiveness.
The Vegetation Management Map is shown in
figure 15. A full statement of goals, objectives and
implementation procedures is available from the
board. The strategy includes cutting lanes for
anglers and predator fish, cutting access across the
north lobe twice a year, and cutting the shoreline
vegetation along homeowners' property and the
county park once a year.
After considering this option, the group decided
to amend it to provide for three years of contract
harvesting. It was then left to the 1995 annual
meeting to decide whether to purchase a
harvester, continue contracting, or revise the
strategy for controlling excessive vegetation.
Vote to adopt: 98 yes, 39 no.
Implementation
• The Vegetation Management Committee,
chaired by Sam Horsemann, will solicit a
weed harvesting contractor based on the
budget provided by the annual meeting. As
-------
17
part of a feasibility analysis, the committee
will visit at least three communities that
operate their own equipment and then
make a recommendation to the annual
meeting about purchasing equipment for
Lake Hale. They will also provide informa-
tion on the likelihood of the district receiv-
ing cost-sharing funds from the Wisconsin
Waterways Commission.
FIGURE 15. Vegetation management map.
• About 50-100 acres, primarily in the north
lobe, will be cut one to three times each
summer. The newsletter will provide free
advertising for anyone offering or desiring
shoreline clean-up services of individual lots
(good employment opportunity for teens).
• The 1995 annual meeting will decide
whether to purchase equipment.
/_ Northern spawning
Fishing lanes to
be cut in June,
July, and August
Area to be cut in
June and August
-------
18
A model lake flan for a local community
OPTIONS
Control alien species.
Eurasian water milfoil and purple loosestrife
have invaded the lake and surrounding
wetlands. Rusty crayfish and zebra mussels
may also damage the aquatic ecosystem.
The district could systematically monitor
these invasions and develop prevention
and control strategies as appropriate.
Vote to adopt: 139 yes, 0 no.
B0JSSI
H4RBGR
EXOTICS I
CLEAN YOUR BOAT
AND TRAILER
Implementation
• Carol Hern, who manages the county park,
has agreed to erect a sign at the public
access by July 1, 1993 warning boaters
about the dangers of spreading exotic
species.
• By December 31, 1993, the Exotics
Committee will collect a library of materials
on exotic species infesting lakes, subscribe
to publications on the topic, and interview
state and local officials about die situation
in Minnesota.
• Starting in 1995, the committee will submit
an article on exotic species for each issue of
die newsletter.
• The Exotics Committee, under the leader-
ship of Dr. Selma Kirkson, will develop a
strategy for controlling alien species by
1996.
• The committee will also prepare an annual
report to the board.
• The self-help monitor may be trained to
systematically look for problem species.
OPTIONS
Reduce agricultural runoff.
The Wisconsin Nonpoint Source Pollution
Abatement Program is a statewide effort to
protect lakes and streams from pollution not
directly associated with industries or sewage treat-
ment plants (point sources). With help from Ted
Walinski (County Land Conservation
Department) and Daryl Roberts (DNR), Lake
Hale might be designated a Priority Lake when
the St. Croix River Basin Area-wide Water
Quality Plan is updated. Funds from the program
could be used to reduce runoff from farms in the
watershed.
Vote to adopt: 110 yes, 21 no.
-------
From considering options to making decisions
19
Implementation
• Commissioner Elder Tobatz has volunteered
to provide leadership for this effort; as a
county board member, he sits on the Land
Conservation Committee. Ted Walinski
will provide staff assistance.
• The district will apply for Lake Male's desig-
nation as a Priority Lake during 1994.
• Priority Lake designation will be obtained
and contracts signed by July 1, 1995.
• University of Wisconsin—Extension will
provide educational support on best
management practices for landowners with
property in the watershed.
• Cost-sharing agricultural practices will begin
by April 1, 1996.
OPTION 7
Reduce construction site erosion.
The lake district does not have the authority to
regulate land use or construction practices.
However, it can apply for a lake planning grant to
hire legal experts to develop ordinances regulating
construction site erosion control and stormwater
management. The draft ordinances would then
be considered by the Town of Meadowview Board
and the Phantom County Board.
Vote to adopt: 126yes, 10 no.
Implementation
* Jennifer Bates (UW—Extension) and Daryl
Roberts (DNR) will help the district
develop the planning grant application by
August 1, 1994.
• A private attorney will be hired to draft the
ordinances. Jennifer and Daryl will provide
examples from other communities.
Ordinances will be drafted by May 1, 1996.
• Jennifer and Duane Peters (code administra-
tor) will hold educational sessions for local
officials and interested builders and citizens.
1 Duane Peters will be asked to advise the
commission on the best strategy to get ordi-
nances adopted. The ordinances will be
adopted by September 30, 1996.
OPTION: $
Conduct a sanitary survey.
The Lake Hale District can request sanitary
powers from the Town of Meadowview. Such
powers allow the district to physically inspect
septic systems, bore in drainfields, or use
"snooper" equipment in the water in front of
homes. Since correction orders would be issued
through the Environmental Health Department,
the county sanitarian would be involved; she
might potentially involve the private sewage
consultant from the Wisconsin Department of
Industry, Labor, and Human Relations. A DNR
lake planning grant could fund 75% of the effort.
Vote to adopt: 62 yes, 74 no.
OPTION 9
Purchase ecologically and
aesthetically sensitive land.
Five parcels of land need protection.
1) The Sunset Point Park Association is
largely defunct and the property owners are
looking for a stronger organization to
manage their private park.
2) Undeveloped shoreland between Sunset
Point and Hale Creek and the wetlands
immediately behind the shore berm are
valuable fish and wildlife areas. Currently,
two private owners hold these lands.
3) Alice Knight is willing to consider donat-
ing Shelter Bay Island to a responsible orga-
nization under a deed restriction that
prevents the erection of any buildings on
the island.
4) The Northern Heights Subdivision
Association owns Northeast Island;
covenants prevent any human activity on
the island.
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20
A model lake plan for a local community
5) Lakeview Bluffs development, proposed for
the southwest corner of the lake, would
provide 185 homesites with a clubhouse
and marina on the waterfront. The owners
of these lots would overburden the lake and
the construction would destroy an impor-
tant vista.
Lake protection grants, available through the
DNR Lake Management Program, could pay up
to 50% of the appraised value of such properties.
Vote to adopt: 115 yes, 19 no.
Implementation
• Elicia Horace, a Minneapolis attorney who
knows Alice Knight, has volunteered to
negotiate the donation of Shelter Bay Island
to the district and expects to complete the
transfer to lake district ownership by
January 30, 1996.
• Bob Lark, a long-time resident of Sunset
Point, will work with Elicia to obtain a
consensus among the old Sunset Point
Homeowners Association members to
transfer the park to district ownership and
management by July 1, 1997.
• Bob and Elicia will also pursue purchase or
easements on the low land between Sunset
Point and Hale Creek. They will also seek
state lake protection grant funds for this
purpose, which has a projected completion
date of July 1, 1998.
• The Land Use Committee is so concerned
about the potential development of backlots
on Lakeview Bluff that it wants to continue
fund-raising to purchase the property. A
state grant and foundation support will be
pursued, and the Nature Conservancy
contacted. The committee hopes to
complete the purchase by January 1, 1999,
and pay off any mortgage by January 1,
2009. If possible, an option-to-purchase
agreement will be negotiated immediately.
OPTION 10
Lobby for stronger enforcement of
county zoning laws.
This option proposes that the Land Use
Committee meet regularly with Duane Peters of
the County Planning and Zoning Department to
report illegal construction around the lake and
share other concerns. Committee members could
testify when variances are requested from the
County Board of Adjustment or when rezoning
cases go before the County Zoning Committee.
For example, Dream Estates may attempt to have
the Bluffs in Section 15 rezoned from a forestry
to a residential area. Attempts may also be made
to convert some farmland zoned Al for
"Exclusive Agriculture" to "Residential."
The Lake Hale District might join with other
county lake organizations to follow up on
stronger shoreland ordinances and more aggres-
sive enforcement by the zoning office and the
district attorney. Periodically, a formal zoning
audit could be conducted with the assistance of
the DNR. The Wisconsin Association of Lakes
could advocate for stronger state legislation.
Vote to adopt: 112 yes, 25 no.
Implementation
• If the district is unable to prevent rezoning
or to purchase the Lakeview Bluff property
owned by Dream Estates, the Land Use
Committee will carefully monitor the
development process and perhaps negotiate
a development layout less damaging to the
natural beauty of the bluffs and shoreline
below. The committee will advocate that an
independent lake capacity study be
commissioned by the county and paid for
by the developer.
• The Land Use Committee will serve as a
Shoreland Watch and be expanded to seven
members. The committee will regularly
inform Duane Peters, the county code
administrator, of building or remodeling
that may not conform to shoreland zoning
or other regulations. The committee will
meet with Duane at least twice a year.
-------
From considering options to making decisions
21
1 Elder Tobatz, our county supervisor, is being
encouraged to ask for a seat on the County
Planning and Zoning Committee.
' The Land Use Committee will attempt to
get one of its members appointed to the
next vacancy on the County Board of
Adjustment. At least one member of the
committee will attend all County Planning
and Zoning meetings and Board of
Adjustment meetings.
' A zoning audit will be completed by
December 31, 1995 and again by
December 31, 2005. The county district
attorney will prosecute at least one shore-
land zoning violation each year. All wet
boathouses will be removed from the lake
by 2020.
OPTION 11
Operate a water safety patrol.
State funds are available to share die cost of oper-
ating a water safety patrol. If the Town of
Meadowview delegated its authority to the Lake
Hale District, the district could adopt its own
ordinances and operate the patrol. A trained law
enforcement officer, a patrol boat, and a citation
system would be needed. The lake could be zoned
for different uses as shown on the proposed lake
use map (fig. 16). Some of diese regulations
already exist through die Town of Meadowview,
but lack enforcement. Jennifer Bates (UW-
Extension) could help the community arrive at a
consensus. The ordinances would be reviewed by
the DNR boating safety specialist.
Members amended diis option to direct the
commissioners to study the seriousness of lake use
conflicts and report their findings and recom-
mendations at the 1996 annual meeting.
Vote to adopt: 89 yes, 41 no.
Implementation
* A new Recreational Use Committee will be
established to monitor the conflicts
between lake users—both on the water and
between water and shoreland users. The
committee will provide complaint forms,
summarize die results, add its own observa-
tions, and make recommendations to the
board and the annual meeting. The district
may recommend changes in the operations
-------
22
A model lake plan for a local community
of the county park and in patrolling by the
DNR warden, or the county sheriff's
deputies. Subject to approval at the annual
meeting, the committee may seek authority
from the Town of Meadowview to adopt a
more detailed lake use ordinance.
1 Complaint forms to register conflicts
between lake users will be available at the
county park bulletin board (1995) and in
the lake district newsletter (1994-95). The
forms will be tabulated to document user
conflict and indicate trends for discussion
by the 1996 annual meeting.
1 Residents are also being encouraged to
videotape boating violations for review by
the committee and the DNR conservation
warden.
FIGURE 16. Lake use map.
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-------
From, considering options to making decisions
23
OPTION 12
Conduct an intensive
educational effort.
Shoreland property owners and public users often
unwittingly damage the lake ecosystem, making
the recreational experiences of others less enjoy-
able. Many people would probably change their
behavior if diey realized they were harming the
lake or other people. While such education does
not cost very much in terms of dollars, it requires
a long-term commitment and a lot of persistence.
To educate our members, we could publish a
newsletter, continue our monitoring efforts,
include an educational element in each annual
meeting agenda, and circulate videos on lake-
related issues. To educate our leaders, we could
require that they attend the Wisconsin Lakes
Convention. To educate the general public, we
could maintain an informational bulletin board
and stock brochures at the county park and the
Lake Hale overlook.
Vote to adopt: 136yes, 3 no.
Implementation
' Susan Bukoltz has volunteered to edit the
newsletter. She will be assisted by Harry
Holtz, publisher of the Phantom County
Reporter. Newsletters will be sent to all
district property owners and residents,
the town board, Elder Tobatz (County
Board Supervisor), Ted Walinski
(County Land Conservation
Department), Duane Peters (County
Planning and Zoning), Jennifer Bates
(UW-Extension), Chris Harms (DNR
Conservation Warden), Daryl Roberts
(DNR Inland Lake Coordinator),
and staff of the Extension Lake
Management Program, UW-
Stevens Point, in May,
August and January.
The problems
identified in the
1989 nominal group process and
the surveys that followed will
receive special attention. The newsletter will
direct readers to further sources of informa-
tion such as the BBS-Lakes electronic
bulletin board available at 800/562-5552.
• Kathie Jansen will continue as the self-help
volunteer. She and Art Belder have taken
more than 85 readings in the past six years.
Hank Arnold has agreed to assist with the
expanded program of water chemistry analy-
sis. The DNR will continue to store the
information and provide an annual report.
' The secretary will be responsible for arrang-
ing a 20- to 40-minute educational program
at each annual meeting with Jennifer's assis-
tance.
' Tiny Starr will contact public agencies and
conservation groups to obtain a video
library. "All Night Video" at the intersection
of the freeway and Highway 762 has agreed
to house and distribute the educational
videos free of charge, beginning in August
1994.
-------
24
A model lake flan for a local community
1 At its fall meeting, the board will provide
funding for four district representatives to
attend the annual spring meeting of the
Wisconsin Association of Lakes held in
conjunction with the Wisconsin Lake
Convention. Other interested citizens will
also be encouraged to attend.
' Joyce Sears and Elder Tobatz will contact
the county about establishing a bulletin
board at the county park. Permission to
build the board will be obtained by
March, 1995, and construction
completed May 15, 1996. Harold Route,
who just retired as district engineer with
the Wisconsin Department of
Transportation, will contact the depart-
ment about erecting a display at the
Highway 762 overlook. Permission to
build a display at the overlook will be
obtained by December 31, 1994, and the
display will be built by July 1, 1995.
Hilary Opitz has agreed to provide the
commission with a draft design for the
display. Wes Dirkson will draft a brochure
which will be available by May 1, 1995.
' By January 1 of each year, four commu-
nity leaders will have agreed to attend the
Wisconsin Lake Convention.
-------
25
Timelines summary
i Activity
/. District leaders attend Wisconsin
Lakes Convention
2. Three issues of newsletter
published per year
3. Public access sign on exotic
species erected
4. Apply for planning grant or
construction site erosion and
stormwater management ordinance
5- Contract harvesting
6. Land Use Committee meets
semi-annually with County Code
administrator
7- Land Use Committee member
attends county zoning meetings
8. Collect materials on exotic species
9. Self-help monitoring
1 0. Educational program at
annual meeting
11. Vegetation Management Committee
visits other communities
12. County district attorney prosecutes
one shoreland violation
13. Complaint forms available to
document conflicts between lake users
14. Permission to erect bulletin board in
15. Article on exotics in each newsletter
16. Video library of lake materials
available
17. Apply for Priority Lake status
18. Permission to build display at
overlook
19. Display at overlook built
20. Bulletin board erected in county park
1993
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26
A model lake flan for a local community
Timelines summary (continued)
' - ' :!• M - ') i !
Activity Year completed or continuing , I j
21. Construction site erosion and
stonnwater management ordinances
drafted
22. Sign contracts for Priority
Lake work
23. Decision on purchasing harvester
24. Zoning audit conducted
25. Transfer Shelter Bay Island to
lake district
26. Cost share ag practices under
Priority Lake grant
27. Recreational Use Committee
recommendations on conflict
management
28. Present strategy to control
exotic species
29. Construction site erosion and
stonnwater management
ordinances adopted
30. Transfer Sunset Point Park to
lake district
31. Purchase lands or easements
between Sunset Point and
Hale Creek
32. Purchase Lakeview Bluff
33. Pay off mortgage for
Lakeview Bluff
34. All wet boathouses will be
removed
1993
1994
1995
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1997
1998
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1999
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2000
2005
2010
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2020
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-------
27
Have we been successful? Evaluating our efforts
We have put forward an ambitious effort to
protect Lake Hale. Our success will depend on the
volunteer efforts of many people, and each of us
will have a highly personalized perception of our
success.
A more objective evaluation of our efforts can be
made by checking the implementation boxes in
the timelines summary. It will be fairly easy to
determine if we have achieved these objectives. Of
course, we will not meet all of them according to
our timelines. We may not meet some of them at
all. But such an evaluation will help us understand
how well we have done. More importantly, it will
help the next generation, entrusted with the stew-
ardship of this lake, to plan for the care of Lake
Hale—as we are doing on our watch.
-------
28
Mini-directo ry
OUR COMMISSIONERS
Joyce Sears, Chair
OFFICE PHONE: 612-414-2220
LAKE ADDRESS: 2502 County G
Phone: 888-2627
HOME ADDRESS: Same
Phone: SAME
Paul O'Malley, Sec.
LAKE ADDRESS: 4271 W. Lakeshore (Lake Hale resident)
Phone: 888-1841
HOME ADDRESS: Same
Phone: SAME
Peter Synch, Treas.
OFFICE PHONE: 612-748-1111
LAKE ADDRESS: 18 Northern Hgts
Phone: 888-1401
HOME ADDRESS: 2711 Little John, Bloomington, MN
Phone: 612/776-4748
Sarah Robertson, Town ofMeadowview
OFFICE PHONE: 721-2018
HOME ADDRESS: 1801 Halverson Rd.
Phone: 888-4678
Elder Tobatz, Phantom County
OFFICE PHONE: 721-2018
HOME ADDRESS: 1879 Halverson Rd.
Phone: 888-7172
OUR TOWN BOARD MEMBERS
Sarah Robertson, Chair
OFFICE PHONE: 721-2018
HOME ADDRESS: 1801 Halverson Rd.
Phone: 888-4678
Dave Tobatz
OFFICE PHONE: 888-1061
HOME ADDRESS: 2602 Halverson Rd.
Phone: 888-4678
Adolph (Tiny) Tonnes
HOME ADDRESS: 1890 Tbwnline Rd.
Phone: 888-2686
OUR COUNTY BOARD REPRESENTATIVE
Elder Tobatz
HOME ADDRESS: 1879 Halverson Rd.
Phone: 888-7172
COUNTY OFFICES
Land Conservation, Ted Walinski
Rm 14 Courthouse, Phantom City
Phone: 721-1818
Planning & Zoning, Duane Peters
Rm. 180 Courthouse, Phantom City
Phone: 721-4601
Environmental Health, Tasha Holman
Rm 184 Courthouse, Phantom City
Phone: 721-4445
University of Wisconsin-Extension, Jennifer Bates
Rm 101 Courthouse, Phantom City
Phone: 721-4422
WISCONSIN DEPARTMENT OF NATURAL
RESOURCES
Conservation Warden, Chris Harms
1801 Oak St., Phantom City
Phone: 721-4701
DNR Inland Lakes Coordinator, Daryl Roberts
DNR District Office, Eau Claire WI
Phone: 467-1531
Editor's note: For the actual names, addresses and telephone numbers of community leaders and agency resource people in your
locality, request a. copy of the Lake List from your county Extension office.
-------
xttliors: Lowell fiessie is a professor of hitraaiildimeiisions of natural resource management at the College of Natural
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-------
CHAPTER 4
Problem Identification
A lake problem is something that prevents you from using the lake the way
you want to (Chapter I defines this as a "limitation"). You can usually iden-
tify lake problems by simply listening to lake users' complaints. When boat
owners find they can't use the lake because it's choked with weeds, for example,
they have clearly identified a problem.
This chapter will help you (see Table 4-1) — and all lake users, managers, and
associations:
• Identify problems.
• Put problems in perspective for a specific lake.
• Understand how to diagnose the causes, not the symptoms, of
problems.
• Define the causes of the lake's problems.
Common Lake Problems
A number of lakes within a region may suffer similar problems; rarely is a problem
unique to a particular lake. The next few pages address the most widely occurring
lake problems, ranging from algae to user conflicts.
Identifying the problem is but the first action in the process of reaching a so-
lution; you will take a number of other steps before you learn enough to prepare
a plan. This chapter also directs you to appropriate parts of this manual that will
help you evaluate alternatives for solving these problems.
Algae
A source of food and energy for fish and other lake organisms, algae are a vital
part of a lake ecosystem. Elevated nutrient levels can produce too many algae, re-
sulting in noxious blooms in the water column or on the nearshore lake bottom
and on rocks or aquatic plants. Large algal growths reduce water clarity and in-
hibit the growth of other plants; they can also deplete oxygen and cause fishkills,
as well as taste and odor problems in water and fish.
But most of all, excessive algae are ugly; their blooms and tangled, filamen-
tous masses certainly destroy the aesthetic pleasure of viewing the lake. Colonial
and filamentous blue-green algae usually cause these unsightly scums, although
other algae can also form blooms and mats.
Filamentous: long, thin
cylindrical cells attached one
to another.
101
-------
Managing Lakes and Reservoirs
Table 4- 1 . — Summary of Chapter 4.
Common Lake Problems ..,,'.. :•...';.
Excess algae
Excess attached plants
Exotic species
Shallow water depth
Turbid water
Toxins
Acidity
Salinity
Swimmer's itch
Leeches
Fecal coliforms, pathogenic
bacteria, and enteric viruses
Undesirable fishery
User conflicts
Taste and odor
; Problem Identification
, Obtaining Professional
Advice .
Information Sources
Produce unsightly algal blooms
Restrict lake use
Reduce native species and use of lake or reservoir
Restricts boating and swimming
Reduces aesthetic values
Restrict fish consumption
Low pH causes reduction in biological community
High salt levels restrict the biological community
Restrict swimming
Restrict swimming
Cause illness, infections, rashes
Increases turbidity and nutrients
Reduce boating and swimming
Affect aesthetics and drinking water
How the water quality of a lake or reservoir compares with
other water bodies in the region
Selection of competent advice
Gather background information about your lake or reservoir
Data Collection and Analysis
Sediment cores
Water and nutrient budgets
Monitoring water qualify
Determine water quality history
Determine contribution of precipitation, surface water, and
ground water to lake or reservoir
Where and when to sample a lake or reservoir
Physical Variables
Sedimentation rate
Temperature
Transparency
Estimate rate water body is filling with sediment
Amount of stratification
Water clarity
Chemical Variables
Dissolved oxygen
Nutrients
Metals and organics
Acidification
Important for fish and nutrient recycling
Elevated amounts cause algal and plant problems
Important for fish consumption advisories
Lowers pH; reduces fish production
• Biological Variables
Bacteria and pathogens
Algae
Macrophytes
Zoopiankton
Animal nuisances
Fish
Trophic State Indices
Important for safe swimming
Measure size and frequency of algal blooms
Measure density and distribution of attached plants
Important as fish food and controlling algal levels
Exotics that cause lake problems
Determine composition of fish community
Compilation of measured parameters to assess water quality
Examples of Using Data to Manage Your Lake
Cedar Lake
Mirror Lake
Example of a shallow lake
Example of a deep lake
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CHAPTER 4: Problem Identification
Aquatic Plants (Weeds)
Aquatic plants are very beneficial to lakes: fish and macroinvertebrates live among
them; zooplankton find refuge there from predatory fish; and aquatic plants stabi-
lize sediment.
But, in excess, aquatic plants are indeed a nuisance. Too many plants limit
swimming, fishing, skiing, boating, and aesthetic appreciation. An all too common
problem in many lakes, excess plants are usually caused by high nutrient levels, in-
vasions of exotic species, and a low water level.
Exotic Plants and Animals
Exotic — or non-native — species have become more of a problem in the last
few decades. Most of these exotics are inadvertently brought to North America
from Europe and sometimes Asia.
• One of the most dramatic historical examples was the invasive sea
lamprey (Petromyzon marinu) in the Great Lakes system. This animal
nearly depleted the lake trout and other salmonid fishery.
• Lakes have also suffered from exotic plants, such as Eurasian water
milfoil (Myriophyllum spicatum) and Hydrilla (Hydrilla vertidllata),
which can limit the diversity of the lake's plant community. These
plants frequently are a problem because they grow close to the lake
surface. Because these plants can grow in great densities, they can
obstruct boating and swimming and reduce aesthetic enjoyment. These
high densities often change the fish community as well, favoring growth
of panfish, such as bluegills, over larger gamefish.
• The common carp (Cyprinus carpio), introduced into North America
in the 1800s, also can have detrimental effects on the lake's ecosystem.
These fish are bottom feeders so they may uproot aquatic plants and
stir up sediments, thereby reducing water clarity and contributing
nutrients to the water-sediment interface. This is especially a problem
in shallow lakes. Often these fish must be drastically reduced to
improve water quality (Meijer et al. 1990).
• A more recently introduced exotic, the zebra mussel (Dreissena
spp.), can have dramatic effects on lake food webs. While zebra
mussels make the water much clearer, they produce far less energy for
use by the higher trophic levels such as zooplankton,
macroinvertebrates, and fish. The Asiatic clam (Corbicula manillensis)
has a similar impact on the lake and reservoir ecosystem.
• Another invader that can have dramatic effects upon a lake is purple
loosestrife (Lythrum salicaria). Although this ornamental plant blooms
with pretty purple flowers, its invasive nature often excludes most
other native plants that also like the water's edge. Loosestrife is also
much less useful to wildlife than native species.
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Managing Lakes and Reservoirs
Shallow Water Depth
Turbidity: clouded water,
usually because it has been
stirred up or has excessive
algae.
Many lakes and reservoirs lose volume — and thus, depth — as sediment fills in
the lake, either by eroding from the watershed or originating from decaying algae
and weeds in the lake itself. Increased sediment generally leads to turbid or
murky water, and reduction in depth usually disrupts swimming, boating, and sail-
ing and encourages extensive weed growth.
Dredging is one of the major lake restoration approaches used to restore
depth, but it doesn't stop soil erosion in the watershed, which is the main cause
of lake infilling.
Turbid Water
Turbid water can result from excessive algae and/or sediment. Sediment usu-
ally increases as a result of soil erosion in the watershed following storms; high
levels of sediment are found more frequently in reservoirs and lakes with major
inflowing streams. In western North America wind-blown soil can increase tur-
bidity.
Fish can also cause turbid water, especially in shallow lakes. Benthivorous
(bottom-feeding) fish such as carp and bullheads frequently stir up the water
when they feed and mate. A study in the Netherlands (Meijer et al. 1990) found
that reducing the carp population decreased nonalgal turbidity.
Toxins
Toxic compounds, such as pesticides or heavy metals, sometimes create problems
in lakes. Toxic compounds can come from discrete sources like wastewater or in-
dustrial discharges, but can also be carried by nonpoint source runoff — and atmo-
spheric deposition. Their principal effect is to restrict human consumption of fish.
Mercury is an example of a toxin that usually does not enter lakes from the
immediate watershed, but from the atmosphere. While mercury levels in the wa-
ter itself are usually not a problem, methyl mercury, an organic compound formed
from mercury, can bioaccumulate in the food chain. As a result, top level preda-
tors such as gamefish can have elevated mercury levels. In nearly all cases, the
mercury has been deposited from the atmosphere; thus, the sources can be far
upwind. Many other toxic compounds, such as PCBs, can enter lakes through at-
mospheric deposition.
Acidity
Increases in lake acidity can radically change the community offish and plant species
in lakes and can also make toxic substances more soluble and magnify their adverse
effects. Like some other toxins, the source of acidity usually is atmospheric. Acid
precipitation can be derived from sulfur dioxide emitted from industrial sources or
from nitrogen oxides in vehicle exhaust upwind from the lake. For lakes to be sensi-
tive to acidification, they must be poorly buffered. This means the water contains
low amounts of chemicals that neutralize acidity. Not all regions of North America
are susceptible to acidification but there are sensitive lakes in the north central and
northeastern United States, New Jersey, Florida, high elevation lakes in the west-
ern U.S. and Canada, and parts of eastern Canada.
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CHAPTER 4: Problem Identification
Salinity
High salt concentrations are usually a problem in the low rainfall climates of west-
ern North America. Irrigation water used to grow crops results in leaching of
high salinity groundwater into downstream water bodies. Irrigation return water
also is high in salts because evaporation concentrates them. High levels of salinity
can harm the aquatic ecosystem, sometimes drastically altering fish and plant
communities.
Swimmer's Itch
Swimmer's itch is caused by the trematode Schistosome dermatitis, a parasitic
flatworm that lives in birds. Snails act as intermediate hosts of the trematode
(also known as a fluke), which can cause itching when it penetrates human skin.
Swimmer's itch can be a problem in lakes populated by snails and waterfowl. Since
normally the trematode doesn't live in humans, these organisms die in the skin
and produce severe itching, but do not cause long-term effects.
Leeches
Leeches commonly live in lakes and can become a nuisance on swimming beaches
because they attach to humans. They don't cause physical problems — just an-
noyance!
Fecal Coliforms, Pathogenic Bacteria, and
Enteric Viruses
In recreational waters swimmers may contract gastrointestinal illness, skin rashes,
and ear and eye infections from contact with water contaminated by fecal
coliforms, e.g., Escherichia coli. Pathogenic bacteria, e.g., Salmonella, and enteric vi-
ruses may also be present. These organisms come from livestock and wildlife ex-
crement, failed on-site wastewater disposal systems, and urban runoff (especially in
areas with combined sewer overflows, i.e., communities that allow stormwater sys-
tems to accept sewage during periods of high rainfall). See American Water Works
Ass. (1990) for detailed information about these organisms.
Undesirable Fishery
Three major factors can upset the balance between panfish and gamefish; these
include too many nutrients, too little oxygen, and acidification.
• When nutrients increase, you may see larger numbers of both
stunted panfish and bottom dwellers such as carp and bullheads. As
noted previously, these bottom dwellers stir up sediments and thus,
can greatly increase turbidity and internal loading of nutrients.
• Coldwater fishes such as trout and salmon often live in the deeper
waters of a lake during the summer, preferring temperatures under
!8°C,and dissolved oxygen levels of at least 5 mg"'.To maintain a
coldwater fishery, the colder waters must have sufficient oxygen.
• Acidification can also shift the fishery's balance, largely by retarding
fish reproduction. More severely affected species may even disappear.
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Managing Lakes and Reservoirs
Ecoregions: Comprised of
relatively homogenous
ecological systems
delineated by geology,
soils, climate, vegetation,
and landform, and
involving interrelationships
among organisms and their
environment.
—Omernik, 1987
,
User Conflicts
Even though boating has always been one of the great joys of lakes — whether
for water skiing, fishing, or just aesthetics — the large increase in boating in re-
cent years (Penaloza, 1991) has produced conflicts among lake users.
To quantify this problem, Wagner (1991) reported that more than one mo-
torboat per 25 acres can be offensive, affecting the quality of the water and sedi-
ment, the flora and fauna, even the stability of the shoreline. Asplund and Cook
(1997) demonstrated that motorboats can reduce macrophyte height and density.
Noise and overcrowding created by motorboats and personal watercraft (such as
jet skis) can also interfere with aesthetic enjoyment.
Time and/or space zoning seems to be the most widely used answer to this
problem. Time zoning restricts certain uses to specific times of the day or days of
the week, while space zoning confines certain uses to specific areas (Engel,
I989a,b;jones,l996).
Taste and Odor
Taste and odor problems are usually related to excessive algae. Algal blooms pro-
duce odors as the algae die and decay — and they can often be quite offensive!
Taste is more noticeable when the water is used for drinking but it can also
affect the taste of fish. Again, excess algae are probably the culprit.
Problem Identification
Depending on physical characteristics of the lake basin and the watershed, and
the quality of incoming water, lakes are suited to different purposes.
• Reservoirs, for example, often are more turbid than natural lakes.
• Some lakes can never be crystal clear, no matter what you do.
• If the watershed is large relative to the lake surface — with highly
erodible, nutrient-rich soils — your lake will always have excessive
algae and weeds regardless of what you do.
Regional differences across the country are also important in understanding
how best to manage your lake. Its quality will be determined by the ecoregion in
which your lake lies (Omernik, 1987): its geology, soils, land use, and vegetation.
Lakes in northern Minnesota, for example, have lower nutrient and algal concen-
trations and greater transparency than lakes in southern Minnesota where the
soil is more naturally fertile (Heiskary et al. 1987).
Causes of Lake Problems
Your lake's problems probably resemble those of most lakes in the same ecore-
gion, but to identify what causes them you must understand the interactions both
within your lake (among algae, macrophytes, fish, and other organisms) and be-
tween your lake and its watershed (see Chapters 2 and 6).
A natural combination of these factors may dictate that a lake will always be
highly biologically productive; thus, it would be useless to try to transform it into
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CHAPTER 4: Problem Identification
a perfectly clear lake. If, however, people's activities have caused your lake's
problems, then these effects can be reversed by combining management efforts
in both the watershed and the lake itself.
To distinguish natural from people-caused problems, look at other lakes in
the same region. If the water quality in some resembles yours, and they lie in rela-
tively undisturbed watersheds, then those lakes' problems might be natural. But, if
other lakes in relatively undisturbed watersheds have much better water quality,
then people are probably contributing to the first lakes' problems.
Other lakes in the region with relatively undisturbed watersheds make a
good initial reference point for assessing the effects people may have on your
lake.
You can use numerous tools to identify the causes of your lake's problems:
• Qualitative approaches, such as comparing the target lake to
surrounding lakes, document subjective observations, which can reveal
important patterns.
• Quantitative approaches, such as the models discussed in Chapter 5
and trophic state indices, rely on objective data.
In practice, both qualitative and quantitative approaches are usually consid-
ered.
Using these methods to identify underlying causes of problems usually re-
quires professional assistance. An important step in defining your lake's problem,
therefore, is selecting competent professional advice.
Obtaining Professional Advice
State or regional government or university personnel may be available to advise
you on your lake's problems. These professionals may be county or state lake pro-
fessionals, regional planning agencies, or University Extension personnel. Another
source of guidance is the North American Lake Management Society (NALMS).
Check out their web site (www.nalms.org) for additional information. The U.S. En-
vironmental Protection Agency also has a good web site at www.epa.gov/owow.
Government and university professionals, however, may not actually conduct
the diagnostic study. Often, this is done by a private consultant or as part of a uni-
versity study.
NALMS certifies lake managers: individuals who have satisfied NALMS' re-
quirements to possess the knowledge and experience to understand and recom-
mend solutions for the comprehensive management of lakes, ponds, and
reservoirs.
It is very important to select a competent professional with a proven track
record investigating the types of problems your lake or reservoir may have.
Among the criteria to consider when selecting a consultant are:
• The candidate's (or firm's) experience in conducting lake studies,
identifying the underlying causes, and formulating effective lake
management plans;
• Expertise in limnology, biology, engineering, or other disciplines
associated with lake management;
f the water qualify in
some [lakes] resembles
yours, and they lie in
relatively undisturbed :
watersheds, then those
lakes' problems might
be natural. But, if other
lakes in relatively
undisturbed watersheds
have much better wafer
quality, then people are
probably contributing to \
the first lakes' problems.
Certified Lake Manager:
individual who has satisfied
NALMS' requirements to
possess the knowledge and
experience to understand and
recommend solutions for the
comprehensive management
of lakes, ponds, and
reservoirs.
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Managing Lakes and Reservoirs
• Past performance in conducting similar studies or dealing with similar
problems; and
• The firm's or candidate's capabilities (support staff, office facilities,
equipment) to address the problems in the lake.
Information Sources
Before you begin to analyze your lake, obtain all existing information on both the
watershed and the lake. Watershed districts, sanitary districts, county extension
offices, county soil and water conservation districts, and city, county, and regional
planning agencies usually have maps, land-use data, or aerial photographs of the
watershed and lake. In addition:
• Water quality data may be available on the inflowing streams or the
lake itself from state water quality agencies and federal agencies such
as U.S. Geological Survey, U.S. Fish and Wildlife Service, U.S. Bureau of
Reclamation, and U.S. Army Corps of Engineers.
• Fishing maps might be available that show the surface area, depth
contours, location of inflowing streams, coves, and embayments, and
other features of the lake that can be important in the diagnosis.
• Recent aerial photographs taken during mid- to late summer can show
the extent of plant beds in the lake.
• Creel census records from state fish and game agencies can provide
valuable information on historical changes in the fish community and
lake productivity.
• Watershed land-use and topographic maps can help determine the
location and acreage of various types of crops in the watershed and
the soil types, including their potential for erosion; and the location of
feedlots and barnyards, residential developments, forested and open
land, and conservancy districts.
• The locations of wastewater treatment plants, industrial discharges,
and storm sewers can be obtained from the sanitary district, city
health department, and state natural resource or pollution control
agencies.
• Discharge data and data on organic matter (for example, BOD) and
nutrient concentrations in the wastewater discharge usually can be
obtained from the wastewater treatment plant's discharge monitoring
records (required by the U.S. Environmental Protection Agency).
• Estimates of annual runoff of water from the watershed or the
amount of stream inflow to the lake might be available from the city
or county planning agencies, U.S. Geological Survey, or the Natural
Resources Conservation Service.
• Locations of groundwater wells in the watershed also might be
available from these agencies, the local health department, or pollution
control agencies.
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CHAPTER 4: Problem Identification
• If the lake or reservoir supplies drinking water, source water
assessments may be available from your state agency that manages
drinking water programs.
• State and federal agencies may have GIS systems with watershed
information in place. If the water body is a reservoir, the utility or
federal agency who built it will have information.
The potential sources of nutrients, sediments, and organic matter from farms,
wastewater treatment plants, urban areas, and forests can be identified. Many have
been studied and some general nutrient and sediment export coefficients associ-
ated with various land uses have been published (Reckhow et al. 1980). You can
combine these land-use coefficients with the annual runoff coefficients and
wastewater discharge estimates to estimate the total load of material to the lake as
detailed in Chapter 5.
Contact government agencies to see if load allocations (Total Maximum
Daily Loads [TMDLs]) have been established for your lake or reservoir. TMDLs
establish target concentrations for specific pollutants, such as nutrients; an analy-
sis is performed to determine the maximum daily load that is allowed from vari-
ous pollutant sources such as agricultural or urban. If a TMDL has been
established for the lake then much of the necessary diagnostic work has already
been completed. See Chapter 6 for more details.
Data Collection and Analysis
To refine the diagnosis, you will generally need more data. Your preliminary analy-
sis — the existing information you've already collected — will tell you what to
look for.
• If agricultural runoff appears to be a major contributor of nutrients
and sediments, for example, then you need better estimates of loading
from the various agricultural locations in the watershed to determine
which ones are contributing the most to the lake.
• Wastewater discharges to a lake are usually an important source of
nutrients and organic matter. Collect samples to determine the
relative contribution to the lake from wastewater treatment plant
effluent, stormwater sewers, and septic tanks. Estimating input from
private waste disposal systems is covered later in this chapter under
the groundwater section.
Sediment Cores
Often, little or no long-term data exist for a lake, making it difficult to know if its
water quality has even changed, let alone how much it has deteriorated, or what
has caused it. If sufficient funding is available, the best way to obtain these histori-
cal data is to conduct a paleolimnological study of the lake sediments. This will
give you a record of how the lake has been disturbed by both natural and anthro-
pogenic processes. This should be performed by a professional, e.g., a
paleolimnologist.
Although only one sediment core is usually needed, if your lake is large or has
multiple basins you may have to take more than one core (especially if sub-basins
reflect differing perturbations). Date the cores to establish a timeline against which
TMDL: a target concentration
(total maximum daily load)
for specific pollutants.
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Managing Lakes and Reservoirs
to measure water quality changes. Use either lead-210 or cesium-137 measure-
ments. Lead-210 works best in lakes while cesium should be used in water bodies
that are less than 130 years old. (See the section on Estimating the Sedimentation
Rates.)
To evaluate changes in trophic state, examine biological remains such as al-
gae, macrophyte.zooplankton, and insects. These parameters reflect in-lake water
quality changes in nutrients, macrophyte species, anoxia in the hypolimnion, and
fish predation. Changes in chemical and physical variables in the sediments doo
ment water and airshed perturbations.
For example, increased soil erosion may be traced by a higher accumulation
of aluminum and zinc from urban runoff. Sediments also preserve trace metals
such as lead or mercury from industrial emissions. Most important for eutrophi-
cation are the historical nutrient changes — increased deposition of phosphorus
and nitrogen — that sediments preserve.
Figure 4-1 (Garrison and Wakeman, 2000) shows a paleolimnological study of
Long Lake, a 1,000-acre-deep drainage lake in northwestern Wisconsin. The water-
shed was completely forested until logging began in the late 1880s. This initial logging
LONG LAKE
Chippewa County, Wl
Sedimentation
Rate
0 0.02 0.04 0.06 0 0.1 0.2
g/cm2/yr
Accumulation Rate
(g/m2/yr)
15 0 10 20 0 10 20 30
Percentage of
Total Diatoms
Figure 4-1.—Sediment core from a deep drainage lake indicating how watershed disturbances affect a lake's wa-
ter quality (Garrison and Wakeman, 2000). Initial disturbance occurred in the late 1800s during widespread log-
ging in the watershed. However, extensive shoreline development beginning in the 1950s had a much greater
impact on the lake, resulting in increased nutrient delivery to the lake as indicated by elevated phosphorus accu-
mulation as well as dominance of the diatom community by Fragilaria crotonensis. This diatom is found in sur-
face waters with elevated nutrient levels. The algal pigment lutein is present only in green algae. Its decline dur-
ing the 1950s likely reflects declining water clarity as this algal group often grows in the metalimnion. With
declining water clarity, sufficient light does not penetrate to these deeper waters for growth. The high manga-
nese in the upper portion of the core indicates increased anoxia in the hypolimnion in the last five years.
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CHAPTER 4: Problem Identification
increased soil erosion (as shown by an increase in aluminum) and thus, accelerated
the sedimentation rate. However, the nutrient (phosphorus) accumulation rate did
not increase and the lake's water quality was only minimally affected. Shoreline de-
velopment following the logging also had little effect upon the lake.
But more riparian development beginning in the 1950s had a much larger im-
pact upon water quality by substantially increasing soil erosion, which resulted in
a dramatic surge in nutrients. The algal pigment lutein, found only in green algae,
also increased, and the diatom Fragilaria crotonensis, which indicates higher nutri-
ent levels in surface waters, became the dominant diatom. This degraded water
quality still exists; in fact, a large rise in manganese in the last five years indicates
the hypolimnion is becoming more anoxic.
This core reveals that historical logging, even though it dramatically affected
the landscape, had minimal effect upon the lake's water quality. Instead, shoreline
development starting in the 1950s and continuing until the present has been most
detrimental to the lake.
This lake could be restored most effectively by reducing nutrients contrib-
uted by riparian development.
Water and Nutrient Budgets
As described in Chapter 2, the water quality of a lake or reservoir is largely influ-
enced by its watershed, which is usually the major source of nutrients and sedi-
ments to the lake and thus the origin of many of its problems.
This makes it highly important to know the annual nutrient load from the
watershed. You can determine this by measuring the amounts of important nutri-
ents (usually phosphorus) and water that enter the lake. The three natural
sources of water are precipitation, surface water from inflowing streams, and
groundwater.
Precipitation
Precipitation is much less important in the nutrient budget than in the water
budget. Therefore, if funds are limited, this portion of the nutrient budget may be
estimated. Precipitation is collected by various governmental agencies (e.g.,
NOAA, USDA, USFS, USGS) at numerous locations around North America; use
the data from a site near the lake to estimate precipitation for your lake. The val-
ues for nutrient levels in rainfall throughout the country can be found in various
publications.
If you need a more accurate estimate of nutrients (or other variables), col-
lect samples on-site. Automated collectors are available but can be expensive.
Other collection devices, e.g., plastic buckets, can be purchased and maintained by
local citizens. If you use these, be sure to minimize the influence of wind and ex-
clude droppings (nutrients!) from roosting birds.
Surface Water
Determining water flow into and out of the lake and recording changes in lake level
are essential for arriving at the annual nutrient and sediment loads to the lake. This
helps establish the carrying capacity of the lake: that is, the amount of nutrients a
lake or reservoir can assimilate each year without exhibiting problems.
NOAA: National Oceanic
and Atmospheric
Administration
USDA: U.S. Department of
Agriculture
USFS: U.S. Forest Service,
a USDA agency
USGS: U.S. Geological
Survey
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Managing Lakes and Reservoirs
Geodetic: Mathematical
method for determining the
exact position on the earth's
surface.
Significant changes in lake level influence the nutrient and sediment budgets,
so you must monitor the lake level during the study. To measure lake level, place a
staff gauge in the lake and determine its geodetic elevation. Read it either weekly
or biweekly, preferably when the water is calm.
Stream gauging stations must be placed on major tributaries near where
they enter the lake and at the outlet of the lake. You don't usually have to gauge
every tributary, however; the water yields from monitored sub-basins within the
watershed can be substituted for unmonitored basins with similar land use. If you
recognize obvious sources of pollution near a tributary stream, then you should
place another gauging station near that site.
Groundwater
Estimating nutrient input from groundwater is most important in seepage lakes.
No streams run into these lakes, so their only sources of water and nutrients are
precipitation, groundwater, and runoff from riparian development.
When managing groundwater-dominated seepage lakes, such as those found
in Florida, Minnesota, Michigan, New York, Wisconsin, and New England, the
groundwater component of a nutrient budget becomes essential.
Measuring groundwater inputs is more difficult and often more expensive
than determining surface water inflows. Where groundwater would be expected
to contribute very little of the nutrient budget it may not be cost effective to
measure it. In these instances using literature values would be better.
Defining the groundwater contribution to a lake is not as precise as for sur-
face waters. The same general principle, however, holds true: water flows down-
hill. You actually define the groundwater component by measuring the elevation
of the groundwater table relative to the elevation of the lake surface. Where the
groundwater table is higher than the lake, the water is moving toward the lake; if
the groundwater table is lower than the lake, then the lake water is moving out of
the lake into the groundwater.
To define the groundwater basin around a lake, place wells on the surrounding
land and then measure the water level in each well in relation to the lake level. You
must also evaluate the variation of possible groundwater table slopes, soil types,
bedrock types and locations, and location of permeable nearshore sediments.
Figure 4-2 shows how groundwater observation wells monitor the ground-
water inflow below a septic system. In this example, three nests of wells are in-
stalled between the drain field and the lake. Their placement assumes that the
groundwater along this portion of the lake shore flows toward the lake, at least
for part of the year. These wells are sited to intercept the groundwater table at
different levels.
If nutrients from the drain field are moving toward the lake, elevated levels
will be apparent in water samples collected from the observation wells. It is also
important to determine the hydraulic conductivity of the soils to estimate the
rate at which the water is moving toward the lake. It is possible that the move-
ment is so slow that the septic system contributes only a negligible amount of nu-
trients to the lake.
In lieu of the well system approach, several other, more focused techniques are
often employed to locate specific areas within a lake where groundwater is enter-
ing or leaving. Techniques include seepage meters, small tube wells placed directly in
the lake, temperature surveys, and fluorometric/conductivity measuring devices.
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CHAPTER 4: Problem Identification
Water
Table
Septic
System
Groundwater
Observation Wells
Figure 4-2.—Example of how to use groundwater wells to measure nutrients delivered from a septic tank to the
lake. Determination of nutrient concentrations at the different depths and distances from the drain field indicates
the contribution to the lake. Groundwater levels vary throughout the year so it is important to monitor the wells
on a regular basis, especially during higher water levels.
Remember that groundwater flow into or out of a lake often varies consid-
erably from season to season and year to year. For example, when the lake is low,
groundwater often flows into the lake; when lake water levels are high the flow
often reverses, with the lake contributing to the groundwater.
Be aware that groundwater flow into or out of a lake is not usually uniformly
distributed around the lake. Often, groundwater only flows into a lake at a certain
place and leaves around the rest of the lake.
Knowing the quantity of groundwater and the general direction of its flow
can help you decide whether (or how) to sewer your lake. For example, if the
soils are sandy they won't retain nutrients and they will allow septic tanks to eas-
ily seep into the groundwater, which will then carry the nutrients to the lake.
Figure 4-3 shows how to use this information in a lake. Round Lake, a seep-
age lake in northwestern Wisconsin, is fed solely by groundwater, and then only
on the north and south sides. Only septic systems located on these portions of
the lake would contribute nutrients to the lake.
Unfortunately, most lake environments are not this simple and additional eval-
uations often must be made to define the effects of on-site wastewater disposal
systems. Most groundwater evaluations require experienced professionals, so con-
sultants, university faculty, and state and federal agencies usually conduct them.
Monitoring Lake Water Quality
Sampling locations and depths influence the conclusions drawn from the data col-
lected in the lake, so it is important that these stations accurately represent lake
conditions.
The sampling locations and depths for physical, chemical, and biological analy-
ses are associated directly with the properties of the lake.
• In lakes that are nearly round, a single station located over the deepest
point may be adequate.
• More stations will be needed in lakes with branched, finger-like
shorelines or multiple embayments, or long, narrow, natural lakes and
reservoirs (Fig. 4-4).
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Managing Lakes and Reservoirs
Figure 4-3.—Groundwater and topographical •watershed for a seepage lake (modified
from Wentz et al. 1989). Water enters the lake only from the north and south. Septic
systems located in other areas of the watershed would not contribute nutrients and
bacteria to the lake.
Dam
Sampling sites for a multibasined lake.
Figure 4-4.—Examples of sampling sites for reservoirs and lakes with complex shapes.
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CHAPTER 4: Problem Identification
• Large lakes (e.g., >2,000 acres) should be sampled at two sites.
• In deep, stratified lakes, samples should be collected at least near the
surface, in the metalimnion, near the middle of the hypolimnion, and
near the bottom. One station should be in the deepest part of the
lake with other stations in the shallower areas and prominent bays.
• For reservoirs, stations should be located at the river inflow, below
the plunge point, perhaps near the middle, and at the deepest point
near the dam.
• Fewer stations will be needed in shallow lakes that mix continuously
throughout the summer, with samples taken only at the surface and
bottom, but as frequently as for deeper lakes.
• See Cooke et al. (1993) for more detailed sampling descriptions.
Sampling frequency depends on what you want to know. For a general char-
acterization of the lake, collect samples during spring turnover and monthly
thereafter through early fall. You usually don't need to sample during the winter
unless you're concerned about loss of oxygen during ice cover or other problems.
More detailed sampling regimes will be described in the following sections to an-
swer specific questions.
Physical Variables
Estimating the Sedimentation Rate
Although all water bodies fill with sediment over time, watershed activities —
primarily construction and agriculture — can accelerate the infilling. Measuring
the sedimentation rate is more important in reservoirs because they usually fill
more rapidly than lakes. Occasionally, isolated areas in a lake, such as deltas where
streams enter, may be infilling at an unacceptable rate.
Two methods are commonly used to determine recent sedimentation rates
in lakes and reservoirs:
v Method I — determines the radioisotopes cesium-137
or lead-210 in the sediments. Although accurate, this method
is relatively expensive. Lead-210, a naturally occurring radionuclide, is
most useful since it determines the age of each sediment depth deposited
in the last 150 years — but, the sediment core must be at least 130 years
old. Since many reservoirs are not this old, this method will not work in
those systems.
Cesium-137 works well for measuring the sedimentation rate in
more recent sediments. A byproduct of atmospheric testing of nuclear
weapons, Cesium-137 was deposited at its highest level during 1963 at the
peak of atmospheric testing by the U.S.S.R.; thus, the average sedimenta-
tion rate since 1963 can then be calculated. Figure 4-5 shows a I37Cs
profile from East Twin Lake, Wisconsin. The United States began atmo-
spheric nuclear testing in 1954 and the increase of l37Cs in the core repre-
sents this date.
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Managing Lakes and Reservoirs
Cesium-137
- 1963
25
5 10
Cesium-137(pCig~1)
Method 1. Use the radioisotope Cs-137 to determine the sedimentation rate.
Figure 4-5.—Profile of cesium-137 indicating depths where dates 1963 and 1954 occur
in a core from East Twin Lake, Wis. (Garrison, 1995).
v Method 2 — compares the current bottom contours
(the depth to the bottom) with a similar map made
several years before. The water level for these two surveys must
be the same or the depth to the bottom must be corrected if not at the
same water level. To use this method, the depth contours on both maps
must have been accurately measured, which was not always the case with
early maps. So, if you're not sure about the accuracy, use these maps with
caution.
Although this method is far less sensitive, it is satisfactory for natural
lakes and reservoirs receiving large sediment loads, and is much less ex-
pensive than the other method.
The usefulness of these methods depends on your objective. If you're plan-
ning to dredge your lake, you must determine the rate of sedimentation before
you begin. You'd waste your money dredging a reservoir that is filling in at a rate
of 2 inches or more a year if you don't first control erosion from the watershed.
Temperature
Temperature patterns (thermal stratification) influence a lake's fundamental pro-
cesses: the depletion of dissolved oxygen, nutrient release, and algal growth. Fish
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CHAPTER 4: Problem Identification
are sensitive to temperature. For example, salmonids are found in water with a
summer temperature <20°C.
Use an electronic temperature meter to take readings, and take them every
meter from the top to the bottom of the lake. Although sampling is usually done
either monthly or biweekly, how often you sample will depend on what you want
to know.
Temperature measurements can help you decide, for example, whether a
shallow lake briefly stratifies and then mixes periodically throughout the summer.
Take weekly measurements during the summer, in conjunction with measuring for
dissolved oxygen (see the section on dissolved oxygen).
Deeper lakes that remain stratified throughout the summer may require less
frequent measurements to understand general temperature patterns.
Transparency
Transparency is based on the transmission of light through water and is related, in
part, to the natural light attenuation of the water being measured, the amount of
suspended solids in the water, and the natural color of the water.
Secchi depth is probably the most frequently used variable in limnology: it
measures the clarity (transparency) of the water by lowering a 20-cm plastic or
metal disk divided into alternating black and white quadrants — the Secchi disk
— into the water until it can no longer be seen. The depth is first recorded at
that point, then again after raising the disk until it just becomes visible.
The average of these two depth measurements is recorded as the Secchi
depth, referred to as the "Secchi transparency" of the lake. The greater the Secchi
depth, the clearer the lake.
Secchi depth can be correlated with phosphorus and chlorophyll a to deter-
mine how eutrophic the lake is by using the Trophic State Index developed by
Carlson (1977). See Trophic State Indices section for details.
Use the Secchi disk on the. shady side of the boat — and don't wear sun-
glasses since they may allow you to see deeper. Avoid taking Secchi measure-
ments early in the morning or late in the day as the low angle of the sun
precludes accurate measurements of water clarity.
Volunteers in many states and provinces collect Secchi measurements on
their lakes during the summer, usually submitting the data to a government
agency. These data can be used to compare the water clarity of lakes both region-
ally and statewide.
The Great American Secchi Dip-In — coordinated by the creator of the
Trophic State Index, Dr. Bob Carlson — provides a national perspective of water
clarity. Volunteers make Secchi measurements in the U.S. and around the world
for the week around July 4 and Canada Day. These data give scientists and volun-
teers a sense of how transparency varies according to water type, regional geol-
ogy, and land use. Even more important, these annual Dip-In snapshots can be put
together to form a changing picture of transparency over time. You can find the
data from the Dip-Ins at www.dipin.Kent.edu.
Other less subjective measurements are available. These involve using a pho-
tometer that accurately measures photosynthetically available light at different
depths.
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Managing Lakes and Reservoirs
Chemical Variables
Dissolved Oxygen
In shallow lakes that mix periodically during the summer, dissolved oxygen should
be measured at the same time as temperature. Stagnant periods when dissolved
oxygen in the bottom drops to zero followed by mixing periods can result in
phosphorus being released from the bottom and redistributed throughout the
lake — this means algal blooms.
Deeper lakes that remain stratified during the summer need to be frequently
sampled for dissolved oxygen and temperature. To track the oxygen levels, sample
every 2 meters from the top of the water column to the lake bottom every two
weeks from the onset of stratification until mixing in the fall. When dissolved oxy-
gen begins to decline in the bottom waters, sample every meter until the DO ap-
proaches zero (less than I mg L~').
These data can also be used to determine the anoxic factor, which indicates
the lake's health. The anoxic factor, which has been developed by Nurnberg
(1995a) (Chapter 5, Table 5-1), estimates the number of days in a year (or season)
that a sediment area equal to the whole-lake surface area is covered by anoxic
water.
The extent and duration of anoxia is very important for fish and macroinver-
tebrate habitat; so is determining the amount of nutrients coming from the bot-
tom sediments. Figure 4-6 shows an anoxic lake.
Low dissolved oxygen may cause both summer and winter fishkills. During
summer months, the dissolved oxygen in shallow eutrophic lakes may decline fol-
lowing a rapid algal die-off. Natural causes can severely deplete dissolved oxygen,
but so can unwise management; for instance, treating an algal bloom in the entire
lake with herbicides can drastically reduce the dissolved oxygen and cause a
fishkill. Also, lakes that freeze during the winter can lose enough dissolved oxygen
Limit of Anoxia
June
July August Sept
1995
Oct
Figure 4-6.—Extent and upper limit of bottom waters that don't have oxygen during
the summer in Lake Delavan, Wis. (Garrison, 1998). The seasonal limit of anoxia is
determined by temperature stratification and the nutrient status of the lake as well as
the lake's morphometry.
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CHAPTER 4: Problem Identification
to kill fish. To determine the potential for winterkill, DO should be measured at
least monthly. Niirnberg's winter anoxic factor (Nurnberg, 1995b) can also pre-
dict winterkill.
Nutrients
A lake study usually focuses on nutrients critical to plant growth: principally phos-
phorus and nitrogen. Chemical analyses may include total soluble phosphorus,
soluble reactive phosphorus, total Kjeldahl nitrogen, nitrate nitrogen, ammonium
nitrogen, total and dissolved solids — and, occasionally, chloride or potassium —
as indicators of agricultural or urban source problems.
For eutrophication studies, total phosphorus is generally the single most im-
portant nutrient to determine in the incoming and outgoing streams. Phosphorus is
often the key nutrient in determining the quantity of algae in the lake (see Chapter
2). Controlling it is usually the only practical solution to algal growth in a lake.
Although total phosphorus is the most commonly measured form of this nu-
trient, other forms are also present. The bioavailable forms are dissolved or
loosely bound P that is readily available for algal uptake. Concentrations of these
forms (e.g., soluble reactive P and total dissolved P) are necessary to run some
trophic models, e.g., BATHTUB. To determine the amount of these forms of P
present, filter the sample soon after collection to remove particulate matter.
Many lake management decisions will be made based on the total phospho-
rus coming into a lake. Modeling efforts (see Chapter 5) to predict water quality
changes resulting from a project are based on the total phosphorus loading.
Phosphorus measurements are especially important during spring overturn
as this value is used in predicting summer trophic status. If the lake is completely
mixed from top to bottom (DO and temperature profile), take only one sample
just below the water surface. Sample for phosphorus at I meter (39.37 inches)
below the surface biweekly or monthly. If the lake stratifies, extend your sampling
throughout the metalimnion and hypolimnion. Samples taken below the mixed
zone help estimate the amount of internal loading from the bottom sediments
during anoxic conditions (see Chapter 5, Table 5-2 for ways to estimate internal
phosphorus loading).
In relatively large lakes (over 1,000 acres) with very little oxygen in their
bottom waters, internal loading can occur throughout the summer. When condi-
tions are calm, the anoxia may extend into the metalimnion, further encouraging
phosphorus release into the water column.
Strong winds, e.g., a frontal passage, can cause thermocline oscillations; the
resulting water movement pumps this high phosphorus water into the mixed
zone (Stauffer and Lee, 1973). To determine if this is a problem, sample for DO
and phosphorus prior to and immediately following these winds. Since such
storms are difficult to predict, you should collect samples weekly and store; dis-
card them if the winds fail to materialize.
In shallow lakes, elevated pH can also cause internal phosphorus loading
(also see Chapter 5). When algae are actively growing during an algal bloom, they
remove carbon dioxide (a weak acid) from the water column, causing pH to in-
crease. James et al. (1996) have shown that at pH values above 9.5, phosphorus
can be released from the sediments at rates equal to or exceeding release rates
under anoxia. In shallow lakes that experience algal blooms, measure pH weekly
Spring turnover: Process
of water layers in a lake
reversing position, usually in
the spring.
119
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Managing Lakes and Reservoirs
in indication of
acidity in take wafer, pH
liijiEiimi 'an ...m (. ; .. ,
measured on a scale
iiiiiiiiu' "in . .:
sfbto 14.
Mil!:"!; ui-,/ lain!' • ' i
Alkalinity: Measure of
water's ability to resist
changes in pH by neutraliz-
ing acid input.
or biweekly during the summer. If pH levels exceed 9.5, high levels of phospho-
rus may be entering the water column.
The total nitrogen (N) to total phosphorus (P) ratio (N:P) in the lake water
can help determine which algae dominate. For example, look for nitrogen-fixing
blue-green algae when nitrogen is low. This can happen where phosphorus levels
are naturally abnormally high, e.g., central Florida or hypereutrophic lakes.
Metals and Organics
Human health concerns are growing over increasing concentrations of trace metals
(e.g., mercury and cadmium) and organics (such as PCBs) in lakes. Although usually
deposited by the atmosphere at relatively low levels, these toxins bioaccumulate in
the food chain. So, as higher and higher levels of organisms consume food contain-
ing these toxins, their bodies concentrate them. Top-level predators such as game
fish like northern pike and walleye, which people eat, may contain harmful levels of
these toxins even though water level concentrations are very low.
Sampling lakes and reservoirs for these compounds is very difficult and re-
quires highly specialized — and very expensive — ultraclean techniques. Instead,
sample organisms that people eat, e.g., game fish. These are much easier to sample
and they provide more relevant information as to whether these toxins are a
problem. This sampling should be conducted by professionals as specific sampling
methods are required to prevent contamination. Many state agencies routinely
sample such foods. See Chapter 2 for more information on airsheds.
Acidification
An indication of acidity in lake water, pH is measured on a scale of 0 to 14. The
lower the pH, the higher the concentration of hydrogen ions (H+) and the more
acidic the water. A reading of less than 7 means the water is acidic; if the pH is
greater than 7, it is basic (alkaline). Because the pH scale is logarithmic, each
whole number increase or decrease on the scale represents a 10-fold change in
the hydrogen ion concentration.
Many lakes are naturally alkaline and not the least bit sensitive to acid precipi-
tation. Those that have pH values less than 7 can be sensitive depending upon their
location. Lakes in the Upper Midwest are not sensitive unless their pH values are
less than 6.0. In the northeastern U.S., and eastern Canada, lakes with pH values
less than 7.0 can be sensitive to acidification, especially during spring runoff.
Acid rain typically has a pH of 4.0 to 4.5 while pure rainwater would have a
pH of 5.7 as a result of atmospheric carbon dioxide. In contrast, most lakes have a
natural pH of about 6 to 9.
Alkalinity is a measure of the acid neutralizing capacity of water; that is, its
ability to resist changes in pH by neutralizing acid input. In most lakes, alkalinity is
a complex interaction of bicarbonates, carbonates, and hydroxides in the water.
The higher the alkalinity, the greater the ability of water to neutralize acids.
Low alkalinity lakes typically have pH values below 7. When alkalinities are
less than 20 mg L"',the Gran analysis method should be used. The Gran method
(U.S. EPA, 1989) provides information that is referred to as "acid neutralizing ca-
pacity" because in addition to alkalinity, it includes the dissociated organic acids
and other compounds that help buffer (increase alkalinity) the water.
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CHAPTER 4: Problem Identification
Biological Variables
Biological indicators are the best symptom of problems associated with high nu-
trients in a lake or reservoir. These usually include algae and macrophytes (aquatic
weeds), and, at times, the fishery, bacteria, and exotics such as zebra mussels. De-
pending on the perceived problems, you will probably have to examine only some
of these.
Bacteria and Pathogens
Animal waste from barnyards and feedlots can carry harmful bacteria and patho-
gens into a lake. They can also enter water bodies from combined sewer over-
flows during storms.
Ducks and geese can be a bigger problem. In addition to adding nutrients to
your lake, their waste can contribute bacteria such as £ coll. Since it is very diffi-
cult to get rid of waterfowl, you should periodically test the water at swimming
beaches and any other areas where people may drink water. Additional informa-
tion is available in APHA (1992) and AWWA (1990).
The best source of information about bacteria or other pathogens is your
local health department. They usually test waters and deal with these problems.
Algae
Chlorophyll a is the most common measure of the amount of algae in the water
column. The average summer chlorophyll a concentrations can tell you how se-
vere your lake's algal problems are. Peak chlorophyll a concentrations in an
oligotrophic lake may range from 1.5 to 10.5 u,g L"1 — in a eutrophic lake from
20 to over 200 (ig L"1.
To measure chlorophyll a, collect an integrated water sample from the mixed
portion of the lake either by taking water samples from several depths and mixing
them together, or by using a tube that extends through the photic zone. Sample
on a biweekly or monthly basis during the spring and summer.
Microscopic examination can help you identify the types of algae in your lake
and thus, understand the lake's problems. Blue-green algae most frequently cause
aesthetic problems since they can float at the surface, leave a paint-like film on the
shores, and cause taste and odor problems. Other algae can also change the color
of the water; Synura turns it red.
Eutrophic Cedar Lake experiences seasonal phytoplankton changes. June
finds algal levels low in this shallow lake, but even then blue-green algae dominate
(Fig. 4-7). Blue-greens, especially Lyngbya and Aphanizomenon, continue to domi-
nate through July but become less important in August and eventually are re-
placed by the eutrophic diatom Aulacoseira. The algal community reaches its
highest level in September when diatoms dominate. Because diatoms do not float
as well as other algae their dominance indicates the importance of wind, in addi-
tion to nutrients, in structuring the algal community in this large shallow lake.
Photic zone: Upper portion
of the water column that
receives sunlight. This is
roughly two to three times
the Secchi depth.
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Managing Lakes and Reserve
Macrophyte: A plant large
enough to be seen without
magnification.
Phytoplankton
Greens
Golden Browns
Diatoms
Blue-greens
0
June
August.
September
Figure 4-7.—Example of seasonal phytoplankton changes in eufrophic Cedar Lake, Wis.
(Garrison, unpublished data).
Macrophytes
Aquatic plant communities range from completely submerged macro (large) algae
(e.g., Chora or Cladophora) to rooted plants with floating leaves (e.g., water lilies)
to completely submersed plants (e.g., pondweeds) to free-floating plants (e.g.,
duckweed or water hyacinth). See Figure 2-19 for a description.
Macrophyte densities vary seasonally between lakes in an area and among re-
gions. In the Upper Midwest, macrophytes might average several hundred pounds
per acre, while in Florida several tons per acre are common.
While plants may be very dense in eutrophic lakes, the community is usually
fairly simple, often containing large amounts of exotic plants, e.g., Eurasian water-
milfoil and/or hydrilla. An excellent source of information on aquatic plants is the
Aquatic Plant Information Retrieval System (Aquatic Plant Management Society at
www.apms.org).
Survey your plant community once or twice during the growing season. Run
a transect perpendicular to the shoreline toward the deep area of the lake, then
collect samples along this transect either using a modified lawn rake (Deppe and
Lathrop, 1992) or by snorkeling or scuba diving.
Observe the water depth, height of plant growth, species composition, and
density. If you're using the rake method, measure density on a scale of I -5 with 5
being the densest. The rake method will not work on low growing plants, which
must be sampled by hand.
Samples collected by hand focus on a known area (e.g., 0.1 m2) to determine
the actual biomass of the plants. You can also estimate plant quantity on a subjec-
tive scale such as: A = abundant, B = common, S = sparse.
Use this information to create a map of the lake's macrophyte community
that shows their distribution: e.g., emergents, floating leaves, and submergents.
Note the sensitive and especially valuable species. Changes in sensitive species
over time can be a good indicator of changes in a lake's condition.
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CHAPTER 4: Problem Identification
Comparing macrophyte studies between different years can yield important
information about a lake. Fox Lake, Wisconsin, used the rake method in 1994 and
1995 to assess the plant community. The second year, plants were much denser
and grew deeper (Fig. 4-8). The increased density was especially evident at sites
represented by transects 2 and 17. In 1995, the lake was much clearer than in
1994, thus encouraging macrophyte growth.
This macrophyte information can also help you:
• Decide where to concentrate control efforts such as harvesting or
dredging, and
• Predict how deep plants might grow if the water clarity improved.
Since macrophytes provide habitat for fish and wildlife, you probably want to
protect certain areas that contain sensitive or endangered species.
D>
01
CO
0>
Q
I
Plant survey transects
CO
CD
T3
8
I
9 17 20
Transect #
21
22
Figure 4-8.—Macrophyte distribution as measured by the rake method (Asplund and
Johnson, 1996). Transects sampled are shown on the map of Fox Lake, Wis. Macro-
phytes were denser and grew deeper in 1995 because of the greater water clarity.
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Managing Lakes and Reservoirs
Zooplankton
Biomanipulation:
Using biological (usually
predator/prey) relationships
to achieve desired results (see
Chapter 7 for a full
discussion).
Planktivory: consumption
oF zooplankton by fish and
other predators.
Zooplankton are microscopic animals that are an essential part of the food chain.
Because they feed on algae, these animals can significantly increase water clarity
even if the nutrient level is moderate. But zooplankton are also important to the
fish diet: some species such as crappies and perch depend upon them as adults;
and many game fish feed on zooplankton during their early life stages.
Zooplankton should be sampled if you're considering using a biomanipula-
tion technique (e.g., increasing zooplankton to increase water clarity). Collect
samples by pulling a plankton net vertically from the bottom of the lake to the
water surface. Sample on a weekly or biweekly basis following spring turnover
through the fall.
Determine the dominant species and their average length. Some species such
as large Daphnia, commonly called water fleas, are much better at controlling algal
levels. But they're also the zooplankton preferred by fish. You do want to know
whether (and how much) fish are feeding on the zooplankton. If you find large
zooplankters, especially Daphnia pulicaria, you can conclude that fish predation is
not important.
Large numbers of Daphnia can reduce algal levels since they are large con-
sumers of algae (smaller zooplankton consume much less). In many lakes this bio-
manipulation occurs in late spring when edible algae abound following spring
turnover, but there are few planktivorous fish (fish that eat zooplankton).
Even in eutrophic lakes the water is very clear at that time; but this so-called
"clear water phase" is generally short-lived. As the water warms, fish begin to ac-
tively feed on the zooplankton, thus reducing their consumption of algae.
The importance of this can be seen by looking at changes in large Daphnia
and their reproductive potential, which is determined by the number of eggs per
adult female. If they're being eaten by fish, the number of these large Daphnia will
decline even though their reproductive potential increases, indicating they have
abundant food (Fig. 4-9a). In the example from Lake Delavan (Fig. 4-9b) fish are
not eating a significant number of large Daphnia. In September and October even
though food resources are limiting zooplankton growth, Daphnia are still present
in the lake. The reason planktivory is low in this lake is when it was restocked in
1990 following a complete fish eradication, very few fish that eat zooplankton
were added.
Animal Nuisances
Certain animals can become real pests in lakes. Many of these are introduced spe-
cies that have few natural predators — like zebra mussels and rusty crayfish. Even
if you have only a few of these animals, they can soon become a nuisance if not
controlled.
• Zebra mussels and Asiatic clams are a recently introduced exotic
species that can dramatically affect a lake's ecosystem. Once they're in
your lake, they will be very difficult to control. To determine whether
they've entered your lake, you can install artificial substrates in your
lake and periodically examine them for zebra mussels. Many states
have established a monitoring system to track the spread of this
nuisance.
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CHAPTER 4: Problem Identification
Devil's Lake
400
May June July August September October
1986
Figure 4-9a.—Devil's Lake, Wisconsin: Seasonal changes of the large herbivorous zoo-
plankton Daphnia pulicaria (Wis. Dep. Nat. Res. 1988). Because of its large size it con-
sumes large amounts of phytoplankton but fish also eat it. Numbers were high in
spring with an abundance of food and little fish predation. By July, fish predation re-
duced its numbers even though sufficient food was available, as indicated by the in-
creased reproductive potential.
Lake Deiavan
400
June
July
1995
I I
August September October
Figure 4-9b.—Lake Deiavan, Wisconsin: In this lake nutrients are higher so levels of
Daphnia pulicaria are higher than in Devil's Lake. Unlike Devil's Lake, fish predation is
not a problem as Daphnia numbers remain high in September and October despite
limited food resources. Daphnia decline in July and August is caused by invertebrate
predators such as the phantom midge Chaoborus and the zooplankter Mesocyclops
ee/ax (Garrison, 1998).
Rusty crayfish — another introduced species — can have profound
effects upon the fish community and the lake ecosystem in general.
Rusty crayfish are especially aggressive, often wiping out native species.
They feed voraciously on aquatic plants and in some instances have
severely depleted a lake's macrophyte community. To find them, place
baited traps around the shallow water of the lake and examine them
periodically.
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Managing Lakes and Reservoirs
Two native species can also become problems:
• Leeches can become so abundant as to be a problem for swimmers.
Sample them by placing baited traps in swimming areas and
periodically examining them.
• Blood flukes — the organism that causes swimmer's itch — are
difficult to detect. You'll usually know they're around when swimmers
begin to complain. Blood flukes are most common in shallow water,
especially near plant beds and waterfowl areas.
Fish Community
A survey of the fish community can provide useful information on the species
present, their size distribution, and the relative availability of fish prey to the
larger fish predators (e.g., the gamefish species, see Chapter 2).
If fishing is poor, then a survey of the fish community should tell you why. You
may find that:
• The fish species people aren't catching does not even live in the lake.
Lake conditions may not be suitable for its habitat or survival;
conditions could have changed and thus eliminated it; or, it could have
been wiped out by a combination of overfishing and poor
reproduction.
• Or, the species may still be there, but in very low numbers because of
poor reproduction — either because of unsuitable habitat or intense
competition for food with another predator.
• The gamefish population may be large, but in poor condition or
stunted in size because they lack suitable prey.
The fish community can also dictate a lake's water quality, especially in shal-
low lakes, where large populations of benthivorous (bottom-feeding) fish stir up
the sediments, moving significant quantities of nutrients into the water column. In
such cases, you need to estimate the biomass of these fish so you can calculate
how much phosphorus is translocated from the sediments to the water column.
For example, Lamarra (1975) estimated that for every pound of carp O.I I pounds
of phosphorus enter the water column. You may not be able to improve water
quality if you don't significantly reduce or eliminate these fish.
Biomanipulation to improve water quality also depends on properly structur-
ing the fish community. Fish (such as perch and bluegills) that feed primarily on zoo-
plankton can decimate the large zooplankton that normally feed on algae. When
fish that feed on other fish such as pike and walleye are dominant, the zooplankton
community is free to feed on algae and thus, decrease algal levels.
If biomanipulation is to succeed, you must know the number of planktivo-
rous (plankton-eating) and piscivorous (fish-eating) fish in the lake. Many shallow
lakes have not been successfully restored until the number of bottom-feeding fish
has been significantly reduced.
Fishery management practices can be applied to solve most of these prob-
lems, but only if the problem is first identified. The state fish and game agency can
often be enlisted to conduct the fish community survey, to help interpret its re-
sults, and to suggest a fishery management strategy.
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CHAPTER 4: Problem Identification
Additional information about fishery science can be found in Baker et al.
(1993) and on the web site of the American Fisheries Society (www.fisheries.org).
Trophic State Indices
Several indices may be used to compare the severity of a lake's problems with
other lakes in the area. Often referred to as "trophic state indices," they simplify
complicated environmental measurements and can quantify lake changes follow-
ing implementation of protection and restoration practices (Carlson, 1977;
Kratzer and Brezonik, 1981; Walker, 1984).
The trophic state index concept is based on the belief that, in many lakes, the
degree of eutrophication is primarily related to increased nutrient concentrations
— phosphorus, in particular. An increase in phosphorus concentration is ex-
pected to increase the amount of algae (see Chapter 2) as measured by chloro-
phyll a. Simultaneously, water transparency declines (as measured by Secchi disk).
Carlson's Trophic State Index (Carlson, 1977) is the most widely used. It
compares chlorophyll a, Secchi transparency, and total phosphorus concentration.
High index numbers indicate increased eutrophy; low numbers, oligotrophy (low
levels of nutrients and algae, clear water). TSI = 0 represents a Secchi transpar-
ency of 64 meters. Each halving of transparency increases the TSI by 10 units. A
TSI of 50, thus, represents a transparency of 6.6 feet (2 meters), the approximate
demarcation between oligotrophic and eutrophic lakes. See Chapter 5 for the ex-
act Carlson TSI formulas.
Suppose that a lake had a transparency index of 60 before it was restored.
Two years later, as a result of a watershed project that reduced phosphorus load-
ing, the index was 40, indicating an improvement in water quality. A TSI of 40
might be common to undeveloped lakes in the area, perhaps indicating that the
lake has improved about as far as it can. Significant upward movement of the in-
dex in later years would indicate the lake has returned to its previous condition.
The index, therefore, is a useful tool for assessing the lake's current condition and
for monitoring change over time.
The Carlson TSI works well in most lakes that are phosphorus-limited but
poorly in lakes that are nitrogen-limited, suffering turbidity from erosion, or expe-
riencing extensive macrophyte problems (Brezonik, 1984).
Figure 4-1 Oa shows TSI plots for a northern lake of moderate water quality.
By scanning the TSI plots, the lake professional can begin to understand the pat-
terns in a specific lake and appreciate the seasonal variations without having to
analyze phytoplankton and phosphorus concentrations and interpret their rela-
tionships.
TSI values can also be used to detect unusual conditions in a lake. TSI values
calculated for phosphorus, for example, may not be the same as simultaneous cal-
culations of TSI from Secchi disk or chlorophyll a measurements. To understand
this situation, you will have to examine the database in greater detail. At Lake De-
lavan (Fig. 4-1 Ob), a sizable population of large zooplankton suppressed the algae,
thus lowering chlorophyll a and producing clearer water than would be expected
given the phosphorus concentrations.
Another scenario: If the TSI for phosphorus and chlorophyll a are similar but
the TSI for Secchi depth is less, this may indicate that inorganic turbidity or water
color is significantly reducing clarity.
127
-------
Managing Lakes and Reservoirs
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Figure 4-1 Oa.— Plot of TSI in a eutrophic lake (Garrison, unpublished data). All three
indicators are in good agreement.
nn
70 -
' J^mm*mm~% ' •
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=• 60 - ZLt4*.&<^t- *» JX*.
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Figure 4-1 Ob.— Plot of TSI for Lake Delavan, Wis., over a period of 14 years (Robert-
son, unpublished data). All the indicators are in agreement from 1 984 through 1 989.
At this time a number of restoration
measures were performed, including stocking
large numbers of piscivorous fish. Since 1993 this has resulted in much better chloro-
phyll a and Secchi values than would
be predicted from the phosphorus values.
128
-------
CHAPTER 4: Problem Identification
Other indices are more appropriate for specific applications:
• Walker (1984) developed an index for reservoirs.
• Brezonik (1984) developed an index that fits the needs of Florida lakes
and includes situations where nitrogen rather than phosphorus may be
limiting algal growth.
• Porcella et al. (1979) included a term in their Lake Evaluation Index
that represents the amount of lake surface covered by macrophytes.
Using the Data to Manage Your Lake
Amassing all these data is critical to the diagnostic study of a lake; it enables the
lake manager or consultant to understand the severity of the lake's problems and
figure out what has caused them. Only then can a lake management plan be for-
mulated.
To succeed, a lake management plan may first have to concentrate on the
watershed to address the sources of the lake's problems. Correcting the cause of
the problem such as limiting nutrient runoff from fields or streets is always pref-
erable to simply addressing the symptoms in the lake.
If the watershed's contribution of nutrients is not reduced, treating the prob-
lem within the lake is more expensive than necessary and may not succeed. For
example, treating bottom sediments with alum improves a lake's water quality for
only a short time if nutrients continue to pour in from the watershed (Garrison
and Knauer, I984b).
Two examples follow that will help you understand how to use a diagnostic
study to formulate and implement a lake management plan; one is from a shallow
lake, the other from a deep lake.
Cedar Lake, Wisconsin
A large, relatively shallow lake in western Wisconsin, Cedar Lake covers 1, 100
acres with a maximum depth of 28 feet. It had experienced large and extensive
blue-green algal blooms, especially in late summer, and was periodically treated
with copper sulfate.
Lake residents requested a diagnostic study that determined phosphorus
loading from the largely agricultural watershed to be about 1,500 kg per year.
Phosphorus loading models (see Chapter 5) based only on watershed inputs sug-
gested that the in-lake phosphorus value should be much lower than was actually
measured. The mean summer phosphorus concentration was well within the
eutrophic range at 60 ug L"'.
The data, however, showed that both phosphorus and chlorophyll increased
dramatically in late summer. Phosphorus values exceeded 150 ug L"1, causing a
large algal bloom. Temperature and dissolved oxygen profiles taken semi-weekly in
1987, revealed that stratification began in late May and the bottom waters quickly be-
came anoxic. When that happened, phosphorus levels became very high as phospho-
rus was released from the sediments (Fig. 4-1 I). When the lake mixed in late summer,
this phosphorus mixed into the surface waters, fueling the large algal bloom.
Although the lake had an excellent sport fishery, a fish survey also found a
sizable carp population. Of course, these bottom dwellers (as discussed earlier in
129
-------
Managing Lakes and Reservoirs
Oxygen
2'_'.. 4 6
Dissolved Oxygen (mg/L)
Phosphorus
0.00
0,05 , 0.10 0.15
JlPotal Phosphorus (mg/L)"
0.20
Figure 4-11.—Profiles of dissolved oxygen and phosphorus in Cedar Lake, Wis. (Garri-
son, unpublished data). During stratification, P is released from the bottom sediments.
Following mixing, this P is moved into the surface waters where it is available to cause
algal blooms.
this chapter) move phosphorus from the sediments into the water column as
they feed (Lamarra, 1975), raising the phosphorus level throughout the lake.
When the phosphorus budget was revised to include internal as well as ex-
ternal loads (Fig. 4-12), in-lake phosphorus concentrations were accurately pre-
dicted. And the major targets for restoring the lake became the internal loading
of phosphorus from carp activity in the sediment.
Because the sport fishery was so good, using rotenone to eradicate the fish-
ery was not an option (see Chapter 7). Instead, a commercial fishery attempted
to reduce the carp population. Although a large number of carp were removed,
130
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CHAPTER 4: Problem Identification
PHOSPHORUS INPUTS
Carp (40%)
Sediments (26%)
Septic Systems (1%)
Ground water (2%)
Atmospheric (5%)
Watershed (26%)
Figure 4-12.—Phosphorus load for Cedar Lake (Garrison, unpublished data). Nearly
two-thirds of the load comes from internal sources. Therefore, the restoration effort
was targeted toward reducing P input from these sources.
enough remained to contribute a significant amount of phosphorus and summer
algal blooms continued.
To reduce phosphorus release from anoxic sediments, a destratification sys-
tem was installed (Chapter 7). This system consisted of a blower that discharged
300 cfm of air with a manifold system located near the center of the lake that dis-
tributed the air into the water column; The idea was not to directly introduce air
into the water column but instead reduce lake stability so that less wind would be
needed to mix the lake. The blower was turned on before stratification began
(late May) and operated continuously until early September.
This system succeeded in reducing phosphorus release from the sediments
by 70 percent (Fig. 4-13). The lake was still anoxic but for a much shorter period
of time and over a far smaller area.
The destratification system also largely eliminated the algal bloom. Previous
chlorophyll a concentrations exceeding 100 ug L"1 (Fig. 4-14a,b) also declined. Al-
gal levels are still in the eutrophic range with peak summer chlorophyll a values of
about 50 ug L"1. The only way to further lower these levels is to decrease nutri-
ents entering from the watershed and reduce the carp population still more.
Mirror Lake, Wisconsin
Mirror Lake is a small urban lake in central Wisconsin with a surface area of 13
acres and a maximum depth of 43 feet. Mirror Lake had experienced repeated
blue-green algal blooms and winter fishkills (Knauer, 1975), so the city commis-
sioned a diagnostic study to determine the annual incomes of water and total
phosphorus and to examine the lake's water quality.
Although Mirror Lake is classified as a seepage lake with no permanent in-
flowing streams from the watershed, urban stormwater discharged into the lake,
131
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Managing Lakes and Reservoirs
SEDIMENT PHOSPHORUS RELEASE
2,000
1,500 --
,000 -
500 -
1987
1991
1992
Figure 4-13.—Prior to operation of the destratification system, a large amount of P
was released from the sediments during anoxia. The restoration reduced sediment re-
lease by about 70 percent (Garrison, unpublished data).
making it a drainage lake. Studies of water and external nutrient loads during
1972 and 1973 (Table 4-2) revealed that city storm sewers contributed more
than half the phosphorus income to Mirror Lake and thus, should be targeted by
the lake restoration project. The study demonstrated that phosphorus loading
peaked during spring showers and intense late summer rainfalls (Knauer, 1978).
Table 4-2.— Annual phosphorus loads for Mirror Lake, Wisconsin, 1972 and
1973.
SOURCE
Storm sewers
Overland flow
Groundwater
Precipitation
TOTAL
1972 (%)
50
16
21
13
100
1973(%)
57
21
18
4
100
Total phosphorus concentration in the lake averaged 90 jig L"', a very high
value, with extremely high concentrations in the hypolimnion, particularly near
the sediments. This indicated that the sediments contributed a substantial amount
of internal loading.
The algae in the lake during the summer were unlike those found in many
other eutrophic lakes. Massive blooms of a blue-green alga Osdllatoria agardhii
characterized the spring and fall, but the summer season saw this species confined
to the metalimnion (see Chapter 2), while blue-green algae dominated the upper
waters following storms.
A sediment core indicated that storm sewers caused the lake's poor water
quality. Among other things, the core was analyzed for chlorophyll pigments com-
mon in Osdllatoria. The first algal bloom, as recorded by pigments in the sedi-
ments, occurred in the early 1940s, just a few years after storm drainage was
diverted into the lake.
132
-------
CHAPTER 4: Problem Identification
,200
g
o
a.
|
a.
•o
150-
100-
£
a.
o
O
Oct.
Figure 4- 14a.— Trophic state indicators in Cedar Lake prior to the installation of the
destratification system (Garrison, unpublished data).
200
O
April
June
July
1992
August Sept.
Oct.
Figure 4-14b.-Trophic state indicators in Cedar Lake following the installation of the
destratification system (Garrison, unpublished data). This system greatly reduced the
extent of anoxia thus reducing P sediment release that caused the late summer algal
bloom.
133
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Managing Lakes and Reservoirs
The diagnostic study also demonstrated that dissolved oxygen was very low
during the winter. An analysis of the data revealed that this problem was caused
by poor lake mixing during fall months before ice developed. Because of the lake's
small size but relatively deep depth, fall turnover didn't happen until late in the
fall. Much of the lake's volume is in the hypolimnion, and during stratification the
bottom waters accumulate a large quantity of reducing chemical substances.
When the lake mixes, these reducing chemicals consume oxygen, often decreas-
ing dissolved oxygen concentrations to 4 mg L"1 throughout the water column. If
ice forms before enough oxygen is exchanged with the atmosphere, not enough
oxygen is left when it freezes to keep fish alive throughout the winter.
The data from the diagnostic study were used to formulate a lake manage-
ment plan and lake protection and restoration strategies:
• In 1976, the storm sewers were diverted from the lake, reducing the
external phosphorus loading by 50 to 60 percent. Despite this reduction,
lake phosphorus concentrations remained high (Fig. 4-15), very similar to
the prediversion average of 90 ug L"'. Phosphorus released,from the
sediments was recycling phosphorus stored in the sediments from 35
years of storm sewer drainage. These phosphorus-rich waters moved
from the bottom to the upper waters during spring and fall mixing, which
helped maintain the high phosphorus levels.
MIRROR LAKE
0.16
DISSOLVED REACTIVE PHOSPHORUS
Ja Ap Jl Oc Ja Ap Jl Oc Ja Ap Jl Oc
1977 1978 1979
Ju So Do Ma Ju Se De Ma Ju Sa Do
1988 1989 1990
Figure 4-15.—Volume weighted mean phosphorus concentrations in Mirror Lake,
Wis., before, immediately following the alum treatment, and a decade following the
treatment (Garrison and Ihm, 1991). Mean total P concentration prior to the alum
treatment was 90 |a.g/L and 20 (.ig/L following the treatment. By 1988 the P levels had
increased to 32 |a.g/L but this was entirely a result of increased concentrations in the
hypolimnion. Deep •water concentrations a decade following the alum treatment were
still considerably reduced from pre-treatment levels and epilimnetic concentrations
during the period 1988-90 were similar to those experienced following the alum
treatment.
134
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CHAPTER 4; Problem Identification
• Aluminum sulfate (alum: Chapter 7) was applied to Mirror Lake in May
1978 to inactivate the sediment phosphorus release. As shown in Figure
4-15, total phosphorus declined to about 20 ug L"' and dissolved
reactive phosphorus was virtually undetectable for two years following
the treatment.
• Ten years following the alum treatment, the lake was reexamined for
three years. The volume weighted mean P concentration had increased
from 20 ug L"' to 32 ug L" in the hypolimnion, indicating recurrence of
some internal loading — probably because the alum layer was now
buried. By the late 1980s the alum layer was 2 inches (5 cm) below the
sediment surface (Garrison and Ihm, 1991). While the alum prevented
the release of phosphorus from the deeper sediments, phosphorus in
the sediments above 2 inches would be released into the bottom waters
during anoxic conditions. Although sediment phosphorus release was
higher (0.20 mg m2 day"1) than immediately following the alum treatment
(0.07 mg m2 day"1), it was considerably less than the pretreatment rate
of 1.30 mg m2 day"1 (Table 4-3). And even though the mean phosphorus
concentration was higher a decade following the alum treatment, the
summer epilimnetic concentration was similar to that immediately
following the alum treatment (Garrison and Ihm, 1991).
Table 4-3.— Release rates of phosphorus and ammonium measured by
in situ nutrient regeneration chambers for Mirror Lake, Wis. Since ammonium
release rates are not affected by the alum treatment, these figures provide
a further indication of the effectiveness of the alum treatment (Garrison and
Ihm, 1991).
TREATMENT
Pre-alum(1978)
Alum (1978-81)
Post-alum (1990)
PHOSPHORUS
(nig m2 day"*)
1.30
0.07
0.20
AMMONIUM
(mg m day"1)
6.6
5.1
5.4
• The storm sewer diversion and alum application also reduced the size of
the algal blooms. Blue-green algae no longer bloomed following summer
storms and the quantity of the alga Oscillatoria agardhii was considerably
smaller.
• To solve the problem with low dissolved oxygen under the ice, an
artificial circulation device was used in the fall to thoroughly mix the
lake. The circulation unit was turned on at the beginning of November
and operated until the beginning of ice cover (usually early December).
This extended fall mixing ensured that when the lake iced over, enough
oxygen remained in the water column to prevent winter fishkills
(Fig.4-16).
These case histories represent real and highly successful uses of the diagno-
sis-feasibility-implementation approach to lake protection and restoration. Once
the causes of the problems were identified, money was directed to long-term so-
lutions instead of wasting it on temporarily effective treatments (e.g., copper sul-
fate treatments). The lesson here is that lake management should proceed along
step-by-step approaches that are based upon a knowledge of both the watershed
T
he lesson here is that ;
lake management
should proceed along '
step-by-step approaches
that are based upon a
knowledge of both the
watershed and the lake ;
and are directed at the
causes, not the
symptoms of the
problems.
135
-------
Managing Lakes and Reservoirs
MIRROR LAKE
1/12/72
0 24 6 8 10 0.2 4 6 8 10
0
4
8
1 12
2/8/72
2/14/72
0 2 4 6 8 10 0 2 4 6 8 10
12/12/78
1/30/79
0 2 4 6 8 10
8 10
02 468 10 0246810
DISSOLVED OXYGEN (mg/L)
Figure 4-16.—Winter dissolved oxygen profiles for Mirror Lake demonstrating the suc-
cess of the artificial destratification system (modified from Garrison and Ihm, 1991).
Without this system the lake frequently mixed in the fall just prior to freeze up. Be-
cause of the high oxygen demand from reduced substances from the bottom waters,
the DO concentration throughout the water column was low. The destratification sys-
tem prolonged fall turnover allowing sufficient oxygen to become dissolved through-
out the •water column to prevent winterkill conditions.
and the lake and are directed at the causes, not the symptoms of the problems.
Effective lake management plans (Chapter 8) integrate watershed management
practices (Chapter 6) with in-lake restoration procedures (Chapter 7).
References
American Public Health Association. 1992. Standard Methods of Water and
Wastewater. 18th ed. Am. Pub. Health Ass., Am. Water Works Ass., Water
Environment Federation, Washington DC.
American Water Works Association. 1990. Water Quality and Treatment: A
Handbook of Community Water Supplies. 4th ed. McGraw-Hill, New York.
Asplund, T.A. and C.M. Cook. 1997. Effects of motor boats on submerged aquatic
macrophytes. Lake Reserv. Manage. 13:1 -12.
Asplund, T.R. and J.A. Johnson. 1996. Alternative Stable States in Fox Lake, Dodge
County, Wis. Results of 1995 plankton and water quality monitoring. Wis. Dep.
Nat. Resour., Madison.
Baker.J.P., H. Olem, C.S. Creager, M.D. Marcus, and B.R.Parkhurst. 1993. Fish and
Fisheries Management in Lakes and Reservoirs. EPA 841-R-93-002. Terrene
Institute and U.S. Environ. Prot. Agency, Washington, DC.
136
-------
CHAPTER 4: Problem Identification
Brezonik, P.L 1984. Trophic state indices: rationale for multivariate approaches. Pages
441 -5 in Lake and Reservoir Management. Proc. 3r Annu. Conf. N. Am. Lake
Manage. Soc., Knoxville, TN. EPA 440175-84-001. U.S. Environ. Prot. Agency,
Washington, DC.
Carlson, R.E. 1977. A trophic state index for lakes. Limnol. Oceanogr. 22:361 -9.
Cooke, G.D., E.B. Welch, A.B. Martin, D.G. Fulmer, and G.C. Schrieve. 1993.
Effectiveness of Al, Ca and Fe salts for control of internal phosphorus loading in
shallow and deep lakes. Hydrobiol. 253:323-35.
Deppe, E. and R.E. Lathrop. 1992. A comparison of two rake sampling techniques for
sampling aquatic macrophytes. Find. No. 32. Wis. Dep. Nat. Res. Manage.,
Madison.
Engel, S. 1989a. The restructuring of littoral zones. Lake Reserv. Manage. 2:235-42.
. 1989b. Lake use planning in local efforts to manage lakes. Pages 101 -5 in
Proc. Natl. Conf. Enhancing States Lake Management Programs, May 1988.
Northeast. III. Plann. Commiss., Chicago, IL.
Garrison, RJ. 1995. Paleoecological analysis of East Twin Lake, St. Croix County. Wis.
Dep. Nat. Resour., Madison.
•. 1998. Final Report for Delavan Lake, Walworth County Zooplankton Study
for the period of 1995-97. Wis. Dep. Nat. Resour., Madison.
Garrison, RJ. and D.M. Ihm. 1991. First Annual Report of Long-term Evaluation of
Wisconsin Clean Lake Projects: Part B Lake Assessment. U.S. Environ. Prot.
Agency, Washington, DC.
Garrison, RJ. and D.R. Knauer. 1984a. Lake restoration: a five year evaluation of the
Mirror and Shadow lakes project, Waupaca, Wis. EPA 440/5-81 -010. U.S. Environ.
Prot. Agency, Washington, DC.
. 1984b. Long-term evaluation of three alum-treated lakes. Pages 513-17 in
Lake Reserv. Manage. EPA 440/5-84-001. U.S. Environ. Prot. Agency, Washington,
DC.
Garrison, RJ. and R.S. Wakeman. 2000. Use of paleolimnology to document the effect
of lake shoreland development on water quality. J. Paleolim. 24:369-93.
Heiskary, S.A., C.B.Wilson, and D.RLarsen. 1987. Analysis of regional patterns in lake
water quality: using ecoregions for lake management in Minnesota. Lake Reserv.
Manage. 3:337-44.
James, W.R.J.W. Barko.and S.J. Field. 1996. Phosphorus mobilization from littoral
sediments of an inlet region in Lake Delavan, Wis. Arch. Hydro. Biol. 138:245-57.
Jones, W.W. 1996. Balancing recreational user demands and conflicts on multiple use
public waters. Am. Fish. Soc. Symp. 16:179-85.
Knauer, D.R. 1975. The effect of urban runoff on phytoplankton ecology. Verh. Int.
Verein. Limnol. 19:893-903.
Kratzner, C.R. and P.L. Brezonik. 1981. A Carlson-type trophic state index for
nitrogen in Florida lakes. Wat. Resour. Bull. 17:713-15.
Lamarra, VJ. Jr. 1975. Digestive activities of carp as a major contributor to the
nutrient loading of lakes. Verh. Int. Verein. Limnol. 19:2461 -8.
Meijer, M.L., M.W. de Haan, A.W. Breukelaar, and H. Buiteveld. 1990. Is reduction of
the benthivorous fish an important cause of high transparency following
biomanipulation in shallow lakes? Hydrobiol. 200/201:303-15.
Niirnberg , G.K. 1995a. Quantifying anoxia in lakes. Limnol. Oceanogr. 40:110-11.
. I995b. The anoxic factor, a quantitative measure of anoxia and fish
species richness in central Ontario lakes. Trans. Am. Fish. Soc. 124:677-86.
137
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Managing Lakes and Reservoirs
OmernickJ.M. 1987. Ecoregions of the conterminous United States. Freshw. Ann.
Ass. Am. Geog. 77:118-25.
Penaloza, L 1991.Boating Pressure on Wisconsin's Lakes and Rivers.Tech. Bull. No.
174. Wis. Dep. Nat. Resour., Madison.
Porcella, D.B., S.A. Peterson, and D.R Larsen. 1979. Proposed method for evaluating
the effects of restoring lakes. Pages 265-310 in Limnological and
Socioeconomical Evaluation of Lake Restoration Projects: Approaches and
Preliminary Results. EPA 600/3-79-005. U.S. Environ. Prot. Agency, Washington,
DC.
Reckhow, K.H., M.N. Beaulac, and J.T. Simpson. 1980. Modeling phosphorus loading
and lake response under uncertainty: A Manual and Compilation of Export
Coefficients. EPA-440/5-80-011. U.S. Environ. Prot. Agency, Washington, DC.
Stauffer, R.E.and G.F. Lee. 1973. The role of thermocline migration in regulating algal
blooms. Pages 73-82 in E.J. Middlebrooks, ed. Modeling the Eutrophication
Process. Utah State Univ. Logan. Republ. by Ann Arbor Science, Ann Arbor, Ml.
U.S. Environmental Protection Agency. 1989. Handbook of Methods for Acid
Deposition Studies Field Operations for Surface Water Chemistry.
EPA/600/8-84/023. Research Triangle Park, NC.
Wagner, K.J. 1991. Assessing the impacts of motorized watercraft on lakes: Issues and
perceptions. Pages 77-93 in Proc. Natl. Conf. on Enhancing States' Lake
Management Programs. May 1990. Northeast. III. Plann. Commiss., Chicago.
Walker, W.W. 1984. Trophic state indicies for reservoirs. Pages 435-40 in Lake
Reserv. Manage. Proc. 3r Annu. Conf. N. Am. Lake Manage. Soc., Knoxville, TN.
EPA 4401 /5-84-001. U.S. Environ. Prot. Agency, Washington, DC.
Wisconsin Department of Natural Resources. 1988. A Two-year Study of Devil's
Lake: Results and Management Implications. Bur. Res., Madison.
Wentz, D.A., W.A. Rose, and j.T. Krohelski. 1989. Hydrologic component. Pages 5-1 to
5-77 in D.R. Knauer and S.A. Brower, eds. The Wisconsin Regional Integrated
Lake-Watershed Acidification Study: 1981-83. EPRI EA-6214. Electric Power Res.
Inst., Palo Alto, CA.
138
-------
CHAPTER 5
Predicting Lake
Water Quality
Models
Mathematical models express in quantitative terms the cause-effect relationships
that control lake water quality, and can be used both to diagnose lake problems
and evaluate possible solutions. Model formulas are derived from scientific theo-
ries combined with observations of conditions in real lakes. In lake studies, mod-
els are employed in two basic situations:
I. Diagnostic: What is going on in the lake? What is the present water
quality? Models provide a frame of reference for interpreting lake and
watershed monitoring data. They tell the user what to expect in a lake
with given morphometric, hydrological, and watershed characteristics.
These expectations may not always be met, however, because of natural
variation in the observations and unique features of the lake that are
not represented by the model. This result, in turn, can help clarify
important cause and effect relationships.
2. Predictive: What will happen to the lake if we take certain actions?
Models can be used to predict how lake water quality will change in
response to changes in nutrient inputs or other factors. Once the
model is calibrated and verified with baseline conditions in your lake,
you can perform experiments on paper or computer instead of
engaging in full-scale experimentation with the lake itself (a usually
infeasible and inefficient process).
Mathematical lake models can address many questions:
• What did the lake look like before anyone arrived? (pre-development
scenario)
• What is the lake's present water quality? (existing scenario, lake
assessment)
• How will future watershed development affect the lake's water quality?
(post-development scenario)
• What are the most important sources of nutrients to the lake?
• What level of nutrient loading can the lake tolerate before it develops
algae problems? (goal setting, TMDLs [total maximum daily loads])
139
Calibrate: To obtain a best
fit between model predictions
and observed data by
adjusting model parameters.
-------
Managing Lakes and Reservoirs
Validate or Verify: To
compare model predictions
with observed data, using
data that are different from
those used to calibrate the
model, and to conclude that
the results of the comparison
are acceptable.
Mass Balance: The mass of
a substance in a fixed volume
is neither created nor
destroyed. Rather, it changes
only according to the input
and output fluxes across the
volume's boundary, which in
the case of a lake may be its
bottom, surface, or shoreline.
• How much must nutrients be reduced to eliminate nuisance algal
blooms?
• How long will it take for lake water quality to improve, once controls
are in place? (restoration scenario)
• How successful will restoration be? (based on a water quality
management goal such as target levels for lake phosphorus,
chlorophyll, or transparency)
• Are proposed lake management goals realistic? Are they cost effective?
Use modeling only for evaluating those types of problems you understand well
enough to express them in concise, quantitative terms. Some situations, like exotic
species introductions, unique accidents, or unusual weather conditions are not pre-
dictable; therefore, modeling is not possible. Sometimes it's even unnecessary, espe-
cially if the lake or reservoir is well studied and no future changes are expected.
Models are just tools used by lake management professionals to develop
their assessments and recommendations. The lake manager decides whether and
which type of models to use, what supporting data should be collected, how the
models should be implemented and tested, and how the model results should be
interpreted.
Ideally, a model is applied only to situations and conditions for which it has
been tested and verified. If no validated models are available or it is not possible
to validate a chosen model (perhaps for financial reasons), the model's results
should be interpreted with caution. The lake manager's choice of appropriate
models for a given lake or reservoir should be based on regional experience, lim-
nological knowledge, and the types of predictions desired (e.g., detailed versus
spatial-temporal averages). The lake manager should consider how closely the
lake characteristics (e.g., morphometry, hydrology, natural lake versus reservoir)
reflect the characteristics of the lakes that were used to develop and verify a
model.
The many types of lake models differ in complexity, assumptions, data re-
quirements, and methods of calculating results. Most are based on the mass bal-
ance concept where all the fluxes of mass to and from specific compartments
must be accounted for over time. Complex dynamic simulation models such as
"CE-QUAL-ICM" (U.S. EPA, 1997) can make detailed predictions of a lake's re-
sponse to pollution over space and time by using fine spatial grids for compart-
mentalization and small time steps. Such models, however, require a lot of input
and field data for calibration and testing.
Complex models can usually be simplified by making certain assumptions. In
some cases, spatial variation of nutrients in a lake may be unimportant, so you can
eliminate those compartments in the mass balance model. For example, Chapra
and Canale (1991) developed a spatially homogeneous lake model with a separate
sediment compartment that helps them predict the long-term temporal dynamics
of average lake phosphorus concentrations.
You might further simplify a model by assuming the lake is in temporal
steady-state: i.e., its nutrient concentration is no longer changing over time. A
lake's mass balance then reduces to simple algebraic equations that a spreadsheet
can handle for the average lake nutrient concentration. Under this steady-state
assumption, you can compare different scenarios (e.g., pre- and post-develop-
ment), but you can't determine the time it will take to reach the second scenario,
140
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CHAPTER 5: Predicting Lake Water Quality
nor predict temporal trends. Walker's (1987) BATHTUB model for reservoirs
assumes a temporal steady-state but allows for some spatial variation by dividing
the reservoir into basins.
Models should be only as complicated as necessary for the task at hand. Un-
necessary detail built into a model makes it more difficult and expensive to con-
struct and verify. A simple model can be more robust and useful for management
decisions than one requiring difficult to obtain detailed input data and then mak-
ing many detailed predictions that will never be compared to observations (see
U.S. EPA, 1999). Because spatial homogeneity, temporal steady-state, and other as-
sumptions make for simpler lake models that still make useful predictions, such
models are frequently used — and are emphasized in this chapter. A review of
other useful lake models can be found in U.S. EPA (1997).
Modeling eutrophication is the primary purpose of this chapter. The general
concepts of eutrophication (see Chapters 2 and 4) are based on the observation
that nutrient availability (phosphorus in particular), algal production, and fish pro-
duction are strongly correlated. Therefore, increasing or decreasing the phospho-
rus loading to a lake will generally have the same effect on nutrient availability,
algal growth, and fish production.
As will be shown, these relationships can be modeled step by step, starting
with a lake's phosphorus budget, followed by observed relationships between
phosphorus concentration and water quality, and concluding with predictions of a
lake's response to future development or restoration (e.g., through goal-setting
with TMDLs). But lakes and reservoirs have other water quality problems besides
those based on phosphorus, and thus we will also assess the value of establishing
mass balance models for the nutrient nitrogen, total suspended solids (causing
turbidity), and acids.
Eutrophication: The Problem
Excessive nutrients that promote aquatic growth, especially algae, were identified
as the most important problem in 44 percent of all U.S. lakes surveyed in 1998
(U.S. EPA, 2000a). Nutrients were also deemed excessive in more than half of the
lakes with impaired water quality. Therefore, models are frequently used to evalu-
ate eutrophication problems related to algae. Eutrophication modeling is based
on several general observations made in many temperate lakes and reservoirs
over many years:
I. Lake algal growth is usually determined (limited) by the supply of
phosphorus. Even if other factors, e.g., nitrogen or light, become limiting,
algae biomass and blooms usually increase with increasing lake water
phosphorus concentrations (Niirnberg, 1996).
2. Increasing or decreasing the amount of phosphorus entering the lake
over an annual or seasonal period will increase or decrease the
average concentrations of phosphorus and consequently of algae
(as in I).
3. A lake's capacity to absorb increased phosphorus loading without
experiencing higher phosphorus concentrations and consequent algal
blooms increases with volume, depth, flushing, and sedimentation rates.
Robust: Description of a
model that predicts well over
widely varying conditions.
Spatial Homogeneity:
evenly distributed (well-mixed
throughout a fixed volume.
Temporal Steady State:
In the context of a mass
balance, there may be fluxes
in and out of the system, but
combined inputs equal
combined outputs so that the
mass in a fixed volume is
constant over time.
141
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Managing Lakes and Reservoirs
Phosphorus: Phosphorus is
usually measured in units of
weight of phosphorus per
volume of water; for example:
mg/m3 - u.g/L => ppb.
+Total Phosphorus
represents all phosphorus in a
sample.
•Particulate Phosphorus
represents only a certain
fraction that is greater than a
defined size (often 0.45
micron).
* Total Dissolved Phos-
phorus is all phosphorus
smaller than the defined size.
*DRP or SRP (Dissolved or
Soluble Reactive Phos-
phorus) is the part of Total
Dissolved Phosphorus that is
readily available and is often
used as an approximation to
the chemically pure form of
orthophosphate.
In other words, algal growth is mainly controlled by phosphorus. Thus, the
condition of your lake water depends on the balance between the amount of in-
coming and outgoing phosphorus and the volume of water available for dilution. A
large, deep lake with a high flow will be able to handle a larger phosphorus load
better than a small, shallow, or stagnant lake.
Most eutrophication models simply summarize these relationships in mathe-
matical terms. In particular, steady-state phosphorus mass balance models use es-
timated lake inputs, outputs, and lake morphometry to predict long-term average
lake water phosphorus concentration, which in turn is empirically related to vari-
ables indicating algal biomass (chlorophyll), water transparency (Secchi disk
depth), hypolimnetic anoxia (lack of oxygen), and/or fish species abundance and
production (Fig. 5-1). These relationships are called "empirical" because they are
statistically based on the responses of water quality to average phosphorus con-
centration observed in a large number of lakes and reservoirs.
Total phosphorus functions as the currency of water quality, since it is the
primary controlling variable for water quality and is correlated to the others, like
chlorophyll, hypolimnetic anoxia, and transparency that all help define a lake's tro-
phic state (see Chapter 4). It also is more stable and easier to determine. For ex-
ample, a one unit increase of phosphorus yields a certain amount of algae, which
in turn decreases Secchi disk transparency by a certain depth and increases hypo-
limnetic anoxia by a certain amount of time and volume.
Modeling Eutrophication
Eutrophication modeling is a step-by-step process:
v STEP 1. Development of hydrological (water) and nutri-
ent budgets* A lake model is only as good as the data used in its con-
struction. Good hydrological and nutrient lake budgets provide that data. If
no or very little inflow and outflow stream data are available, these flows
can be modeled separately with various degrees of detail. At one extreme,
a watershed simulation model might use 20 years of daily precipitation
data and numerous sub-watershed areas to provide long-term average
water flow. Alternatively and more simply, data derived from other compa-
rable studies can be used to determine approximate water and
phosphorus loads for a steady-state lake model.
TSTEP 2. Calculation of lake phosphorus concentrations
from external and internal phosphorus loading as deter-
mined in Step I. Phosphorus models can simply describe the lake as a
steady-state, completely mixed water body and determine annual average
lake total phosphorus, or they can use a simulation model to specifically
model various lake compartments (e.g., bays and basins, different layers) or
seasons separately, or even detailed phosphorus changes in time and
space. Sometimes a combination of simple and more elaborate models is
useful: the simple model can verify the overall input and output of a more
detailed model.
142
-------
Eutrophication Model Concepts
Loading: .
Modifying factors
Phosphorus loading
Morphometry
Hydrology
Other factors
Factors modifying
lake response
to loading
_ concentration
(Limiting nutrient)
Lake phosphorus
Patterns of /&:£• :?£•:&
response /@£$l&2£*£*^
gp^ Low ^
Phosphorus loading
High Small, stagnant
factors Dissolved P load
Sediment recycle
Low Large, rapidly-flushed
factors Paniculate P load
Stable thermocline
Promote algal growth
and increase
concentration
(Algal pigment)
Chlorophyll-a
Higy!j§||
•gpi'^L.QVJ ^
Lake Phosphorus
Clear, stagnant
••• — ••• O fid MOW
Dissolved P load
Turbid, rapidly-flushed
Paniculate P load
Nitrogen limited
Zooplankton grazing
Decrease water
(Secchi depth)
Transparency
' k
Wligh
Low ^
Chlorophyll-a_
Turbid, colored
Minh cilt
Rapidly-flushed
Shallow
•n
<5'
I
Ul
'l
m
•D
S*
a
§
1
CO
8
ft
!
W
a
n
-------
Managing takes and Reservoirs
T STEP 3. Prediction of water quality from lake phospho-
rus concentration determined in Step 2. Empirical models are fre-
quently used to predict water quality variables from phosphorus. These
models often require only one predictor variable, e.g., average summer ep-
ilimnetic phosphorus concentration, to model the water quality variable in
question, e.g., summer chlorophyll concentration.
T STEP 4. Model verification of lake phosphorus and water quality
predictions from Step 2 and 3 with monitoring data, if available. Model pre-
dictions are compared with observed lake conditions to assess the
sources and degrees of variation of observed and predicted data.
T STEP 5. Forecasting and tracking changes in wafer qual-
ity. Combinations of Steps I to 3 are used to predict possible changes in
water quality. Once the model has been validated for your lake (Step 4), it
can be used to predict the changes in water quality likely to result from fu-
ture changes in phosphorus loading. The model can also remove
anthropogenic effects and thus show you the lake's natural condition.
STEP 7: Development of Hydrological
and Nutrient Budgets
Phosphorus loading changes in response to season, storms, upstream point sources,
and land use. For example, converting a forest into an urban subdivision or shop-
ping center usually increases the amount of phosphorus entering the lake by a fac-
tor of 5 to 20, a result of increased water flow and nutrient concentration - both
related to runoff from impervious surfaces. Evaluating the loading gives us a basis
for projecting how the lake will respond to changes in land use or other factors.
In addition, a detailed mass balance study can determine the relative impact
of various pollutant sources on lake water quality. For example, even though a
stream has a high phosphorus concentration, it may also flow minimally, and thus
contribute very little to the lake.
Loading estimates for each source will vary; they are ranges, not fixed quanti-
ties. Depending on monitoring intensity, calculation methods, and natural variation,
an annual loading estimate for a given stream could vary by a factor of 2 or more.
To directly estimate loading from a source, both flow and concentration must
be properly quantified over the period in question. This is difficult and expensive
because both vary widely in response to season, storms, and other unpredictable
factors. When a monitoring program produces inadequate results, it is better to
use data from a more detailed long-term study of a comparable watershed.
Water Budget
The first step in lake modeling is to establish a water budget. Flows carry pollut-
ants into and out of lakes, and water quality problems cannot be analyzed without
a quantitative understanding of lake hydrology. In fact, the water budget is as im-
portant as evaluating the pollutant concentration because it is needed to quantify
loadings from specific sources. The basic water balance equation considers the
following terms, typically expressed as water volume per year:
Inflow + precipitation - outflow + evaporation + change in storage
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CHAPTER 5: Predicting Lake Water Quality
Figure 5-2 illustrates possible water flows that contribute to the total
budget.
DIRECT RUNOFF
STREAM INFLOW
POINT SOURCE
DISCHARGE
GROUNDWATER INFLOW
LAKE WATER BUDGET
PRECIPITATION EVAPORATION
\ 1
i
\ CHANGE IN STORAGE /
SURFACE OUTFLOW
WITHDRAWALS
GROUNDWATER OUTFLOW
Figure 5-2.—Schematic water budget.
• Inflows may come from tributary streams, point source discharges,
shoreline runoff, and groundwater springs.
• Outflows may include the lake outlet, groundwater discharges, and
withdrawals for water supply, irrigation, or other purposes.
Major inflow and outflow streams should be gauged directly and continu-
ously over the long term. If only short-term data are available, use them in con-
junction with long-term regional climate data (precipitation, evapotranspira-
tion) to calibrate a model that will give you long-term average stream hydrology.
Use estimates (for example, runoff coefficients) to quantify smaller streams.
The change in storage accounts for fluctuations in the elevation of the
lake surface — whether it's "high" or "low" — over the study period; this is
sometimes significant in reservoirs.
Once all flow terms have been determined, check the water budget for bal-
ance. Major discrepancies may indicate an error in an important source of inflow,
outflow, or storage (such as unknown or poorly defined stream or groundwater
flow). It is relatively difficult to establish water balances in seepage lakes because
of the problems and expense of monitoring groundwater flows. Significant errors
in the water balance may indicate a need for further study of the lake's hydrology.
Phosphorus Budget
The cornerstone for evaluating eutrophication problems, the lake phosphorus
budget evaluates and ranks phosphorus sources that may contribute to an algal
problem. The basic concept and mathematics are relatively simple, although esti-
mating individual budget items often requires considerable time, monitoring data,
and expertise.
The following terms are evaluated and typically expressed as phosphorus mass
per year (if an areal load, as phosphorus mass per lake surface area per year):
External load = outflow load + sedimentation - internal load + change in storage
Figure 5-3 illustrates external and internal phosphorus sources that may
contribute to the total budget.
The term external load is the amount of phosphorus per year that enters
the lake from all external sources. It may come from tributaries, sewage treatment
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Managing Lakes and Reservoirs
PHOSPHORUS BUDGET
nmcrr ni IMOPP rneuiriiMinJiN WATERFOWL
DIRECT RUNOFF v & DUSTFALL
STREAM INFLOW v\ i i ^ SURFACE OUTFLOW
^*ACHANGE IN STORAGE /
POINT SOURCE _Jv- — /-^WITHDRAWALS
DISCHARGE V /-^
•GROUNDWATER OUTFLOW
GROUNDWATER INFLOW -""'^-3-
& SEPTIC TANKS /
ANOXIC RELEASE
Figure 5-3.—Schematic phosphorus budget.
plants discharging directly to the lake, precipitation and dust fall, septic tanks,
groundwater, runoff, and waterfowl. Estimating these loads is the most important
and generally most expensive step in the modeling process.
Intensive monitoring programs to define and quantify at least some major
loading sources can pay off in good, reliable results. Lake water is usually moni-
tored for all parameters at the same time so that loadings can be related to lake
responses.
Stream loading, often the largest source, is usually estimated from stream
flow and phosphorus concentrations monitored periodically (weekly, monthly)
and supplemented with samples taken during storms. Storm sampling is very im-
portant, particularly in small streams that flash flood, because a very high percent-
age of the annual loading may occur during short, intense storms. If these events
are not sampled, it will be difficult to develop reliable loading estimates. You might
also try combining monitored hydrology with empirically predicted phosphorus
concentration to arrive at the stream load.
A complete monitored external load budget is so costly and labor intensive —
and takes so long — that, instead, you may want to make indirect estimates based
on the characteristics of your watershed. This method is based on the concept that
two watersheds in the same region and with similar land-use patterns and geology
will tend to contribute the same amount of phosphorus per unit area, and thus data
can be extrapolated from one or more monitored watersheds to others.
Whether this method will work for your lake depends largely on the avail-
ability of good data on regional export coefficients (mass of phosphorus per wa-
tershed area, per year) for the land uses and watersheds in your area. Export
coefficients have been compiled for a number of land uses (see Chapter 2, Table
2-1). This approach is much less costly than direct monitoring and can be as good
or better for long-term predictions, especially when you monitor inflow infre-
quently or for only a few years.
The term outflow load relates to phosphorus leaving the lake in surface
outlet(s); withdrawals for water supply, irrigation, or other purposes; and ground-
water seepage. You can usually measure these flows and concentration, although
if groundwater seepage dominates the outflow, it will be difficult to directly deter-
mine the outflow loading.
The term internal load refers to all internally derived phosphorus. The most
important source comes from bottom sediments that release phosphorus when
their surface goes anoxic. This happens frequently in the summer in eutrophic
stratified lakes. To determine the internal load from anoxic sediments, use either
your lake's phosphorus budget, the phosphorus increase in the hypolimnion, the
146
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CHAPTER S: Predicting Lake Water Quality
Table 5-1.—Anoxic Factor.
The anoxic factor (AF) (Nurnberg, 1995) quantitatively summarizes the extent and duration of
anoxia (lack of oxygen) in stratified lakes. It is based on a series of measured oxygen profiles
and morphometric data and can be computed for any lake or reservoir. To render this index
comparable across lakes of different sizes, AF is corrected for lake surface area by simple
division. Expressed this way, AF is a ratio that represents the number of days in a year or
season that a sediment area equal to the lake surface area is anoxic. Hence its units are d/yr
or d/season; i.e., summer or winter. Anoxic factors can be predicted from average
phosphorus concentration and lake morphometry when oxygen profiles are not available.
To compute AF, first inspect the oxygen profiles and determine the depth at which DO
concentration is 1 mg/L. When this concentration is found about 1 m (3 feet) above the
bottom, the sediment-water interface is likely anoxic, and processes requiring reduced
sediment surfaces, like phosphorus and iron release, will commence. Next, the period of
anoxia (ti in days) must be multiplied by the corresponding hypolimnetic area (a, in m2) and
divided by the lake surface area (A0, m2) corresponding to the average elevation for that
period. These terms of n, numbers of periods at different oxyclines are then added up. In this
way, AF is comparable between lakes, like other areal measures, e.g., areal nutrient loads
and fish yield.
When classified with respect to trophic state, below 20 d/yr indicate oligotrophic
conditions, 20 to 40 d/yr are usually found in mesotrophic lakes, 40 to 60 d/yr represent
eutrophic conditions and above 60 d/yr is typical for hypereutrophic conditions.
A r- -A ti X 01
increase in phosphorus concentration at fall turnover, or laboratory estimates of
sediment release rates coupled with the anoxic factor as a variable to describe
the duration and extent of hypolimnetic anoxia (Tables 5-1, 5-2).
Internal loads can be quite substantial in eutrophic lakes, and, when good
management has reduced external loading, even more than the phosphorus en-
tering the lake from the watershed (Fig. 5-4).
Other internal sources that are usually less important include:
• Phosphorus transport from the bottom of the lake to the epilimnion
(the top) via algal migration.
• Release from shoreline sediments resulting from resuspension and
turbulence.
• Release from sediments caused by changes in pH, and sediment
disturbance by bottom-dwelling fish and macrobenthos (Welch, 1992).
Sedimentation is the downward flux of phosphorus to the sediment. Lake
water quality is usually better with higher sedimentation, because less phospho-
rus remains in the water column to stimulate algal growth.
The term change in storage accounts for changes in the total mass of
phosphorus stored in the water column between the beginning and end of a
study period. Such changes reflect differences in lake volume, average phosphorus
concentration, or both. This term is positive if the phosphorus increases and
negative if it decreases.
Water and phosphorus budgets supply the information necessary to com-
pare the individual loading terms and thus rank sources and identify candidates
for watershed management or in-lake restoration techniques. For example, the
Lake Wilcox phosphorus budget clearly indicates that treating the tributary
Macrobenthos: Insect
larvae and other small
invertebrates living at the
bottom of a pond or lake
(these are actually large
compared to plankton).
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Managing Lakes and Reservoirs
Table 5-2.—Determination of internal phosphorus load in stratified lakes.
Internal phosphorus load is the phosphorus released from lake sediments into lake water. Often it
accumulates in the hypolimnion during stratified seasons and is primarily released from anoxic
sediment surfaces. Internal load (just like external) can be returned to the sediments leading to
various estimates ranging from "gross," which most closely approximates the total amount of
internal load, to various "net" estimates which include some degree of re-sedimentation of
internal load. Five different ways of estimating internal phosphorus load are listed below:
1. Net estimates from complete phosphorus budgets: In a complete mass balance
that includes all external P inputs and the total P loss in the outflow, internal phosphorus load is
implicitly considered. A net internal load can then be computed from the increase in outflow
mass over that predicted from a retention model that assumes no internal load:
net internal load = external load x (Rpred - Rmeas)
where retention (Rpred and Rmeas) is explained in Table 5-3. This estimate of internal load is the
smallest and deviates the most, because it includes sedimentation and precipitation of internal
load. This net estimate is related to internal load by using the same retention model as used for
external loads (Nurnberg, 1998):
net internal load = internal load x (1 - Rpred)
2. Partially net estimates from in situ phosphorus increases in the summer
hypolimnion: Internal load estimated from phosphorus increases in the hypolimnion is
higher than that based on an annual budget (1), because of some sedimentation during that
period.
3. Partially net estimates from in situ phosphorus increases at fall turnover:
Internal load can also be estimated at fall turnover, when the surface water concentrations
increase due to mixing of hypolimnetic phosphorus-rich water with epilimnetic water. Some
additional sedimentation might already have happened before and during turnover, so this
value will probably be slightly below the estimate determined from summer increases in the
hypolimnion (2).
4. Gross estimates from phosphorus release rates and anoxia: The highest
estimate of internal load, which should be closest to the amount of phosphorus actually
released from the anoxic sediment surfaces, can be computed from release rates and the
anoxic area and time, i.e. the anoxic factor. This value should be highest, since it does not
incorporate any sedimentation. When there are no measured release rates available, a
measured phosphorus concentration in the profundal sediment can be used to predict a range
for the phosphorus release rate (Nurnberg, 1988).
5. Gross estimates from complete phosphorus budgets: The equations in 1 can be
combined so that internal load can be estimated as:
internal load = external load x (Rpred - Rmeas) / (1 - Rpred)
For example, long-term averages of internal load (kg/yr) estimates for Lake Wilcox, Ontario
were estimated as follows:
1. Phosphorus budget (net) 39
2. Hypolimnetic increase 135
3. Fall turnover 122
4. Release rate 157
5. Phosphorus budget (gross) 169
The net estimate of 39 kg/yr (estimate 1, that considers a predicted retention of 0.77)
corresponds to an internal load of 169 kg/yr (estimate 5). This is similar to estimate 4 which
does not consider retention of internal load either.
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CHAPTERS: Predicting Lake Water Quality
10000E
TD
OJ
o
05
c
I
1000
100
10
II I I I M
10 100
External load
1000
10000
Figure 5-4.—Internal versus external phosphorus loading (mg/m2/yr) in stratified
lakes with anoxic hypolimnia.
would not reduce eutrophication because it accounts for less than 10 percent of
external and less than 3 percent of total load (Fig. 5-5). And the only way to
eliminate late-summer algal blooms in Cedar Lake was by treating the high inter-
nal phosphorus load (Chapter 4).
STEP 2; Predicting Phosphorus Concentration
Steady-state phosphorus mass balance models usually assume that the lake is spa-
tially homogeneous. They are driven by four fundamental variables calculated
from lake morphometry, and water and phosphorus budgets:
I. The average input phosphorus concentration is the sum of all
external phosphorus loads to the lake weighted by the outflow of water.
Average input phosphorus concentration = external phosphorus load/outflow
This equation represents the "real" average inflow concentration only
when total inflow equals outflow. Where these flows differ, e.g., in
reservoirs, this term has a more theoretical meaning. Typically, outflows
and loads are calculated on an annual basis to even out seasonal
variation.
This basic measure of inflow quality is important in determining how
watershed point and nonpoint sources affect eutrophication of the lake.
Thus, long-term management (as in the TMDL process) frequently
focuses on reducing average input phosphorus concentrations.
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Managing Lakes and Reservoirs
Water Load
Runoff
21%
Atmospheric
40%
Phosphorus Load
Groundwater
17%
Tributary
22%
Groundwater
3%
Tributary
3%
Internal
64%
Atmospheric
8%
Runoff
22%
Figure 5-5.—Relative importance of various sources of water and total
phosphorus for Lake Wilcox, Ontario.
2. The average water residence time (often called hydraulic retention
time) (x) is the average length of time water spends in a lake or
reservoir before being discharged through the outlet.
Average water residence time ft) = lake volume/outflow
Again, outflow is calculated annually to even out seasonal variation. If
total inflow equals outflow, T equals the time required for the lake to
refill if it were completely drained. As residence time increases,
interactions between the water column and bottom sediment have
more influence on water quality. For a given inflow concentration,
phosphorus sedimentation usually increases and lake phosphorus
concentration decreases as residence time increases. At very short
residence times (less than one to two weeks), algae may not have
enough time to respond to the inflowing nutrient supply.
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CHAPTER 5: Predicting Lake Water Quality
3. Mean depth ( z ) is a basic morphometric characteristic of the lake.
Mean depth ( z )= lake volume/lake surface area
Other factors being equal, lakes and impoundments with shallower
mean depths are generally more susceptible to eutrophication problems.
In shallower lakes, light penetrates a larger proportion of total depth to
support photosynthesis, and the greater sediment/water contact can
encourage nutrient recycling.
4. Phosphorus retention defines the fraction of incoming phosphorus
kept in lake sediments, as only part of a lake's incoming phosphorus
leaves by the outflow. It is the most difficult variable to determine as it
depends on sedimentation which in turn depends on morphometry and
hydrology.
Net retention (Rnet) reflects the net result of all physical,
chemical, and biological processes causing vertical transfer of
phosphorus between the water column and lake sediments. Hence, it is
the difference between annual phosphorus sedimentation and internal
phosphorus load.
Rnet= (sedimentation — internal loadj/external load
When internal phosphorus sources exist, Rnet decreases. If Rnet is
known, the steady state lake phosphorus concentration can be
calculated as:
Lake phosphorus concentration = average input phosphorus
concentration x (1— Rnet)
However, because sedimentation and internal load are difficult to
measure, Rnet is rarely available. When complete water and phosphorus
budgets are available, you can estimate net P retention by the difference
between external and export loads:
Rmeas = (external load - export loadj/external load
because (sedimentation — internal load) = (external load — export load).
If Rmeas is substituted for Rnet in the lake phosphorus concentration
equation, average lake phosphorus is estimated by the average outflow P
concentration.
In pre- or post-development scenarios, or when outflow loads are not
available, even Rmeas will not be available. For these cases, empirical
retention models (Rpred) have been developed that predict retention
from water budget variables and lake morphometry. One such model
(Niirnberg, 1984) that incorporates sedimentation only (as it was
developed using data from lakes without any internal load) is:
Rpred = 15/(18+qs)
Where qs (areal water load) = Z/T
If internal load is significant, this Rpred will overestimate net retention
and thus, when used in the lake phosphorus concentration equation,
underestimate predicted lake phosphorus, as happened in Cedar Lake,
Wisconsin (see Chapter 4).
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Managing Lakes and Reservoirs
Conversely, predicted phosphorus concentration will be overestimated
in situations where physical or chemical processes enhance sedimenta-
tion more than predicted by the empirical retention model. This has
been observed in some hard, calcium-rich lakes, in some soft, iron-rich
lakes, and in reservoirs containing large amounts of silt. Until retention
models are developed for these types of lakes, their retention must be
measured directly (Rmeas).
Typically, these equations are used to predict annual average lake phospho-
rus concentrations; however, you can use different combinations of variables
(see Table 5-3) to predict seasonal phosphorus concentrations in stratified and
frequently mixed lakes. These are especially useful in stratified lakes with large
internal loads, where annual average and fall turnover phosphorus concentra-
tions may be out of proportion to their far smaller epilimnetic concentration in
early summer (Fig. 5-6). In these lakes, use the corresponding seasonal phospho-
rus average to predict other lake water quality variables. For example, if chloro-
phyll concentration was determined from annual phosphorus rather than
epilimnetic summer average, it would be greatly overestimated in mesotrophic
Lake Wilcox (observed: 9 u.g/L; predicted from epilimnetic phosphorus: 7 |Og/L;
from annual average phosphorus: 30 Hg/L).
After a change in loading, the lake will take a while to reach a new steady
state. The duration of this lag time increases with the annual water residence
time (T) and the mean depth (z) of the lake.
Table 5-3.—Models to predict phosphorus averages for different seasons in stratified lakes with and
without anoxic hypolimnia (and hence internal load), and in polymictic lakes (Nuernberg, 1998).
Model predictions were compared to measured phosphorus averages in different lake groups. External load (Uxt, mg m"2 yr"1)
values are gross estimates before any settling, internal load (Lint, mg m"2 yr"1) estimates are either "gross" or "net" values in the
stratified lakes, depending on whether the estimates are based on a whole year budget ("net Lint", estimate 1 of Table 5-2) or
estimated from sediment phosphorus release rates and anoxia ("gross Lint", estimate 4 of Table 5-2). If estimate 5 (Table 5-2) is
used as "gross Lint" in model #4 of the table below, it becomes identical to model #1. In polymictic lakes, an "in-situ" estimate of
lini was used that represents a partially net estimate, since it incorporates some loss via sedimentation. Measured phosphorus
concentration averages are: Pann, annual; Pepi, summer epilimnetic; Pfa|i, fall turnover. Retention was either measured from a P
budget (Rmom) or predicted as Rpred- 15/(1 8+qs), where qs, annual areal water load (m yr"1). The expression of Uxt/qs in these
models is the same as average input P concentration as defined in the main text, n.a., not applicable
(I)1 Ux./qs (1-Rmeas)
(2) U/q, (1-Rpred)
(3)2 Uxt/qs (1 -Rpred) + net Ut/q*
(4) (Loxt + gross Lini)/qs (l-Rpred)
(5) Uxi/q, (1-Rprod) + gross Lint/qs
(6) Uxi/qs (1-Rpred) + in-situ Lin,/qs
(7) (Uxt + in-situ Lini)/qs (1 -Rpred)
_p
~rann
_p
~rann
>Pepi
==rann
=lann
>Pfall
n.a.
n.a.
p
' ann
-
~rann
>Pfall
n.a,
n.a.
— P — P .
— rann/ — repj
^^ i ann
n.a.
n.a.
n.a.
-------
CHAPTER 5: Predicting Lake Water Quality
600
^500
S400
P: 300
-| 200
J 100
0
1993 1994 1995 1996 1997 1998 1999
hyper-eutrophic
eutrophic
mesotrophic
Figure 5-6.—Seasonably of phosphorus concentration in the surface (0-4 m or circa 0-12 feet) and bottom water
(1 m or circa 3 feet above bottom) of a stratified mesotrophic lake (Lake Wilcox, Ontario [after Nurnberg, 1997]).
Note that the surface phosphorus concentration (open circles) is only around 30 Lig/L during summer, but can in-
crease to over 100 jig/L at fall mixing events. Hypolimnetic phosphorus concentration (filled circles) is much higher
during summer than surface phosphorus and ranges between 100 and 600 (ig/L .
STEP 3: Relationships Between Phosphorus
and Other Water Quality Variables
The value of determining lake phosphorus concentrations becomes obvious
when comparing phosphorus levels to other water quality data. Phosphorus con-
centrations, especially epilimnetic summer averages, correlate highly with algal
biomass indicators like summer averages of chlorophyll and Secchi disk transpar-
ency (Cooke et al. 1993). Use regression equations to predict algae abundance
over a wide range when only phosphorus data are available (Fig. 5-7).
Other important water quality variables pertaining to oxygen levels in the
bottom water (Fig. 5-8) correlate to phosphorus as well, especially when you con-
sider the shape of the lake basin (Nurnberg, 1996). Several models use phospho-
rus or chlorophyll to predict variables related to fish (number of species, biomass,
or yield) for certain geographic regions (Nurnberg, 1996). For example, the
number of coldwater fish species (of the families Salmonidae, Coregonidae and
Gadidae) is considerably higher in oligotrophic lakes as compared with eutrophic
lakes (Fig. 5-9).
To simplify the assessment of water quality in specific lakes, Carlson (1977)
developed the Trophic State Index (TSI, see Chapter 4). This system, used by
many states to classify lakes, essentially relates phosphorus and chlorophyll con-
centrations to Secchi disk transparency in an index that is consistent with north-
ern lake behavior (Table 5-4; Fig. 5-4). The actual equations to compute TSI (Table
5-4) were derived from a data set of 60 to 150 northern natural lakes (Carlson,
1977) calculated similar to those depicted in Figure 5-7. The TSI helps compare
water quality variables; its scale is calibrated so that an increase of index units
corresponds to a decrease of transparency.
153
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Managing Lakes and Reservoirs
100.0r
D)
.r:
O
10.0
1.0
1—I—I I I I I I 1 1—I I I I I 11 ;~i f—i i i T i i
20
15
10
£ 5
I
TO
Q_
(0
C
0}
1—I I I Mll| 1—I I I I lll| 1—I I I I III
10 100
TP (Hg/L)
1000
Figure 5-7.—Summer epilimnetic averages of algae biomass indicators versus total
phosphorus summer averages in temperate freshwater global lakes. Regression lines
are for equations in Niirnberg (1996): Chlorophyll, Secchi disk transparency. Some of
the turbidity in colored lakes (x) is due to colored organic acids, not only algae. There-
fore, it is useful to know the color value in brown water lakes.
Table 5-4.—Carlson's Trophic State Index.
Trophic State Index values can be computed from the various summer average water quality
variables (Carlson, 1977; U.S. EPA, 1998c).
TSI of transparency = 60 - 14.41 In(transparency)
TSI of chlorophyll = 30.6 + 9.81 In(Chl)
TSI of phosphorus = 4.15 + 14.42 ln(P)
TSI of nitrogen = 4.45 + 14.43 ln(N)
Hypolimnetic anoxia can be considered in the TSI concept as well. The TSI of the anoxic factor
(Table 5-1) can be approximately computed as:
TSI of anoxic factor = 10 + AF (Nurnberg, unpublished).
154
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CHAPTER 5: Predicting Lake Water Quality
0
100
TP (jjg/L)
,
AHOD: The areal hypolim-
netic oxygen deficit describes
the rate at which oxygen
concentration declines in the
hypolimnion (units of mg
oxygen per square meter of
hypolimnetic area per day).
It does not indicate extent or
duration of anoxia.
Figure 5-8.—Indicators of hypolimnetic ox/gen versus total phosphorus concentration
averages in temperate freshwater lakes. Regression lines are for equations in
Nurnberg (1996): areal hypolimnetic oxygen depletion rates (AHOD); anoxic factor
(Table 5-1).
155
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Managing Lakes and Reservoirs
0)
"o
0)
Q.
V)
"w
iZ
"co
"o
o
7
i
6
5
4
3
2
1
0
_ i i i i _[
Oligotrophic Mesotrophic Eutrophic
•
— —
- • •
- • • •
. .. .
• •«• •»«•«!•• •
- ...... |......M| ,. \ . {. -
10 20 30 40 5(
TP (Hg/L)
D
Figure 5-9.—Number of eoldwater fish species versus total phosphorus concentration
averages in Ontario lakes on the Precambrian Shield. Lines indicate trophic limits.
STEP 4: Model Verification
Water quality models must be tested with real field data under baseline condi-
tions to ensure that they work as expected before they are used. Many of the
simpler models are designed to predict average water quality conditions over a
certain period of time (a growing season or year) and often over the whole lake,
even though water quality varies over time and space. Thus, when collecting field
data to calibrate a model, averaging usually covers several dimensions. Remember:
actual observations can comprise a large range of values.
^ Depth: The top, mixed layer (epilimnion) is the part of the water col-
umn that is generally averaged. Vertical variations within this layer are
usually small. But for "whole-lake" phosphorus estimates, you must also
account for accumulation in a potentially anoxic hypolimnion.
V Sampling Station: Although a small, round lake is so homogenous it
should need only one station, generally, sampling stations should be lo-
cated in different places in the lake. Water quality in most large lakes and
reservoirs may differ significantly (from oligotrophic to hypereutrophic)
from station to station. In such situations, a measurement for the "average
water quality" may be meaningless; it would be more appropriate to divide
the lake or reservoir into segments for modeling purposes where outflow
from one segment serves as inflow to the next.
^ Seasonal: Phosphorus and especially transparency and chlorophyll
concentrations can vary significantly at a given station from one sampling
date to the next during the growing season. It is not unusual, for example,
for the maximum chlorophyll concentration to exceed two to three times
the seasonal average.
156
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CHAPTER 5: Predicting Lake Water Quality
In lakes with internal phosphorus sources (i.e., phosphorus release
from anoxic bottom sediments), phosphorus levels vary as well, depending
on the relative importance of the internal phosphorus source. In these
lakes, surface water phosphorus concentrations are lowest in early spring
and highest in the fall after the upwelling of bottom water (Fig. 5-6). Spe-
cialized models have been developed to account for internal load in these
lakes (Table 5-4).
V Annual: Average water quality also varies year to year because of cli-
mate fluctuations, particularly stream flows and factors that control thermal
stratification. For example, compared to a dry year, a wet summer can signif-
icantly increase runoff and external nutrient load and may trigger algae
blooms. Monitoring programs extending over at least several years, depend-
ing on the flushing rate, are often recommended to characterize baseline
conditions and provide an adequate basis for lake diagnosis and modeling.
Given that analytical error as well as natural variability will affect field mea-
surements, it may be more realistic to consider measured water quality as a range
of values rather than as a specific value. With care, you may arrive at an estimate of
lake water quality with small "Confidence Intervals." A Confidence Interval will give
the probability (usually 90 percent or 95 percent) that the "true" average is con-
tained within that interval. Any slight improvement or deterioration in water quality
within the Confidence Interval will be difficult to detect, but when it becomes com-
parable to or greater than the expected variation (as indicated by the Confidence
Interval), the change will become "statistically significant" and detectable.
Similarly, model predictions of lake water quality may have a range or Confi-
dence Interval associated with them because of the natural and analytical variability
of data inputs to the model and from any empirical relationships used. Model pre-
dictions can be confirmed or rejected on the basis of whether the Confidence In-
terval of their prediction overlaps the Confidence Interval of the observed baseline
parameter. If there is no overlap, then possible systematic errors in the model's in-
put parameters or in model assumptions and structure must be evaluated. In some
cases, it may become clear that model assumptions or structure are inappropriate;
this conclusion in itself can be a useful diagnostic tool for assessing lake function.
It is possible that predicted or observed Confidence Intervals are too wide
to provide a useful test of the model. Only an improved modeling program can
resolve this. Another problem might be unknown systematic errors in the model
leading to its rejection. These may be canceled out by predicting relative changes
in lake conditions rather than absolute values when two scenarios are compared.
Informed interpretation of model results based on an adequate lake and water-
shed monitoring program reduces the risk of errors that could lead to false con-
clusions and poor management decisions.
STEP 5. Forecasting and Tracking
Changes in Water Quality
Step 5 is probably the most important reason for lake modeling because it is the
only way to predict future conditions. In this step, models developed and verified in
the previous steps are applied to future (or past) scenarios. You can use changes in
phosphorus loading to predict changes in average phosphorus concentrations,
157
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Managing Lakes and Reservoirs
chlorophyll, and transparency. These predictions can then help you set future
water quality targets based on phosphorus.
Be sure to select an appropriate target for the problem at hand. For exam-
ple, if the management goal in mesotrophic Lake Wilcox was to decrease annual
average phosphorus concentration, in-lake restoration might decrease the inter-
nal load (more than 60 percent of total load; Fig. 5-5). However, if early summer
algal biomass is targeted, reducing the internal load may not work, since, in this
stratified lake, it won't affect the epilimnion until late summer.
You should formulate targets as concentrations rather than loads because it
is the concentration that reflects a lake's trophic status and water quality. In par-
ticular, loading targets would not adequately protect water quality in situations
(such as reservoirs) where water flow could be decreased. In these cases, lake
concentrations could increase despite constant loading.
In a rare situation loading targets may be too restrictive. For example, 21 pos-
sible development scenarios were modeled for Lake Wilcox to find out which
combination of additional developed areas would result in "an external phosphorus
load no greater than existing conditions" (the legal management goal). External load
values predicted for several scenarios are shown in Figure 5-10. Only scenarios 4,5,
and "Hyp" complied with the external load target; but phosphorus concentrations,
algae biomass, and anoxia are predicted to decline for some of the less stringent
scenarios as well (Fig. 5-10) because extreme measures in runoff treatments from
developed areas will probably dilute the increased phosphorus loading.
Some typical restrictions include a certain percentage increase of phospho-
rus concentration above pre-development concentrations. The Ministry of the
Environment in Ontario, Canada, proposes a factor of 1.5 increase above prehis-
toric annual average phosphorus concentrations as target values for its more than
100,000 lakes on the Canadian Shield (Hutchinson et al. 1991). The Swedish gov-
ernment endorses a maximum of twice the background levels of phosphorus (and
nitrogen) as a national target (Swedish EPA, 1994). Compliance with these targets
can be evaluated only by using phosphorus models in which current anthro-
pogenic sources are first included and used to verify the model and then removed
to arrive at a pre-development phosphorus concentration.
The TMDL (total maximum daily load) program is based on target values as
well. States must identify and list water bodies where state water quality stan-
dards are not being met and establish TMDLs to restore them. A TMDL specifies
the amount a pollutant needs to be reduced to meet water quality standards
(which ideally should be based on concentration), allocates pollutant load reduc-
tions among pollutant sources in a watershed, and provides the basis for restoring
a water body through point source and nonpoint source controls. To set TMDLs
for eutrophication-related problems, use variations of Steps I to 5, including
phosphorus modeling and predicting water quality variables (Table 5-5).
In another approach, the ecoregion concept helps assess the quality of indi-
vidual lakes (Omernik, 1991). This concept realizes that the natural trophic status
of lakes depends on its watershed's land surface form and use, natural vegetation,
and soils. Typically, your watershed is assigned to a pre-defined ecoregion based
on its location. Medians of trophic state variables based on lakes in EPA's Storet
database are available for different ecoregions. Next, certain lake characteristics,
like average phosphorus or summer chlorophyll concentration, are compiled for
each region separately. Then the characteristic of each individual lake is compared
with measures of the central tendency (median) for all lakes in that region. A lake
should fall below the median, i.e., it should belong to the half of the better lakes.
158
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CHAPTER 5: Predicting Lake Water Quality
120-
§110
I
'S 100
5
a.
90
uj 80
70
llUJL
0 1 2 3 4 5 Hyp
Scenario
35
25
20 -
12
11
i10
I9
a_ Q
2 *
,0
§ 7
6
5
0 1 2 3 4 5 Hyp
Scenario
Ihnl
0 1 2 3 4 5 Hyp
Scenario
3.5
3.0
E 2.5
1.5
i 1 1 1 1 1 r
55
I"
3
40 -
-, 1 , , , r
01 2 3 4 5 Hyp
Scenario
0 1 2 3 4 5 Hyp
Scenario
Figure 5-10.—Model predictions of external'phosphorus load (A) and response variables
(B, C, D, E) for several different hypothetical scenarios in Lake Wilcox, Ontario. Existing
conditions are indicated by broken lines. Existing phosphorus load (A) was the legal tar-
get value and must not be exceeded in future development. Scenarios 0 to 5 include ad-
ditional development in the watershed: "0", without any treatment, "1" includes several
storm treatment ponds, "2" to "5" include storm treatment ponds and various levels of
additional treatment. "Hyp" is the model prediction for existing watershed conditions
with the in-lake treatment of hypolimnetic •withdrawal (see Chapter 7).
Ideally, it should fall in the quarter of the best lakes or should be restored so that
it does. To set limits based on the ecoregion concept, apply variations of Steps I
to 4, including phosphorus modeling and the prediction of water quality variables.
Hypolimnetic with-
drawal: Lake outflow is
taken from the hypolimnion,
not from the surface of a
lake. The surface outlet is
usually dammed.
159
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Alonogmg' Lakes and Reservoirs
Table 5-5.— Benefit of modeling for the TMDL process.
Several steps in TMDL development and implementation planning may require data gathering
and the use of predictive water quality models. For example, the following information needs
are often associated with the first six components (a-f) described below:
a. Target
Identification
b. Deviation from
Target
c. Source
Identification
d. Allocation of
Pollution Loads
e. Implementation
Planning
f. Monitoring/
evaluation
—Develop numeric target for water quality conditions (e.g., criterion)
—Translate criterion to numeric loading capacity level (quantified
pollution load from all sources, including background, necessary to
meet criterion, e.g., through a predictive analysis of pollution in the
waterbody)
—Quantify the amount and timeframe of deviation between
current/future loading levels and the loading capacity level
— Identify all sources or source categories
—Quantify the amount of load from sources, including natural
background
— Ensure that allocations will lead to attainment of water quality
standards
— Estimate the effectiveness of controls/management measures
— Determine that controls/management measures are sufficient to
achieve the TMDL allocations
— Determine the likelihood of actual implementation of control
strategies
— Assess whether the implementation of controls/management
measures has occurred
—Evaluate the effectiveness of controls/management measures and
whether they are meeting allocations
— Demonstrate attainment of water quality standards
Chapter 5.2, Section 5, from Report of the Federal Advisory Committee on the TMDL Program, U.S. EPA, 1 998.
Modeling Other Pollutants
In some situations, particularly in reservoirs, factors other than phosphorus may
strongly influence algal growth and water quality. Appropriate models for these
situations are more complex than those discussed in the previous section, al-
though the general concepts and approaches are similar.
Nitrogen
An important nutrient, nitrogen often correlates to water quality variables just
like phosphorus. Epilimnetic summer averages of total nitrogen and phosphorus
positively correlate over a wide range of concentrations in large data sets of
North American and worldwide lakes (Fig. 5-11, Nurnberg, 1996). Nonetheless,
most lakes are phosphorus- rather than nitrogen-limited, or both, and attempts
to reduce lake nitrogen levels in these lakes may have little effect on algal biomass.
In fact, a comparison of apparently nitrogen-limited lakes (as determined
from their N:P ratios) with those that were phosphorus limited could find no dif-
ference in their phosphorus to chlorophyll relationships (Nurnberg, 1996). When
nitrogen actually affects algae, it's usually because either the phosphorus level is
high or nutrient inputs are very low. In the first case, it makes more sense for lake
managers to target phosphorus rather than nitrogen and to establish phosphorus
160
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CHAPTER S: Predicting Lake Water Quality
D)
n.
1000r-
100 r
10 100
TP (ug/L)
Figure 5-11.—Summer epilimnefic nitrogen versus phosphorus concentration averages
in temperate freshwater lakes. Regression lines are for equations in Niirnberg (1996).
budgets instead of nitrogen budgets. In the second case, the lake probably does
not have a eutrophication problem.
The ocean, however, is usually nitrogen-limited, and thus nitrogen pollution
from coastal watersheds can cause eutrophication in estuaries and other coastal
salt water. Northern European communities have developed strict nitrogen ex-
port limits to prevent the Baltic Sea from becoming more eutrophic (Swedish
ERA, 1994), and similar controls exist in some American coastal states (U.S. EPA,
I998a). Lake nitrogen budgets can help predict and eventually control nitrogen
exports from lakes in coastal watersheds to sensitive marine environments.
Nitrogen mass balance models are more difficult to construct than those for
phosphorus (see Steps I and 2). Although nitrogen export rates are available for
various land uses and regions, nitrogen retention can be measured in the field
only with great difficulty, primarily because nitrogen is transformed so easily by
blue-green algae and bacteria. Atmospheric nitrous oxides must also be taken
into account. Some nitrogen models have been developed, however, based on em-
pirical (observed) data (Bachmann, 1980; Windolf et al. 1996).
Suspended Sediments
Siltation has been identified as the third major problem after nutrients and metals; it
severely affected 7 percent of all US. lakes surveyed in 1998 (U.S. EPA, 2000) and was
the major problem in a quarter of all lakes rated with impaired water quality.
Suspended sediments can cause turbidity (thus limiting light), impair fish
spawning and feeding habitat, and create taste and odor problems. A sediment
budget can be established much like a nutrient budget:
External load = outflow load + sedimentation - resuspension + change in storage
As with phosphorus, net retention can be estimated as the difference be-
tween in- and outflowing mass over incoming mass. In addition, sediment loss
equations are available that model the settling of suspended sediment.
161
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Managing Lakes and Reservoirs
Acidity
Many lakes throughout the world have been acidified by the deposition of acids
from the atmosphere or acid drainage from mines. The majority of models ad-
dressing these problems emphasize soil conditions and soil-water interactions,
because atmospheric acid deposition is neutralized primarily by the soil around
lakes. Only in lakes with a relatively small watershed-to-lake-area ratio will in-lake
processes dominate. Consequently, these models are not very useful in predicting
the effects of acid lake liming or acid mine drainage on the chemistry of lakes.
Most models are based on the concept of alkalinity (or ANC, acid neutraliz-
ing capacity), rather than pH. Unlike pH, alkalinity is not affected by changes in
weak acids such as carbon dioxide, making its measurement and prediction more
reliable. The appropriate definition and measurement of alkalinity in a lake de-
pends on the major weak acid buffering systems present (e.g., carbonic acid, weak
organic acids, or aluminum hydroxides).
Detailed alkalinity budgets have been constructed for some acidified lakes
and catchments, but they have only been used to calculate direct alkalinity reten-
tion or release. The retention of alkalinity has not been predicted in a more gen-
eral way as has been done for phosphorus in lakes.
Summary and Conclusions
Mathematical models are useful both in diagnosing lake problems and in evaluat-
ing possible solutions.
Eutrophication modeling is a step-by-step process, including construction of
hydrological and phosphorus budgets, calculation of average phosphorus concen-
tration, prediction of water quality from lake phosphorus, model verification, and
forecasting of alternative scenarios.
For in-depth coverage of this subject, consult Reckhow and Chapra (1983),
Welch (1992), and Cooke et al. (1993). Case studies, including restoration efforts
using different models and scenarios as well as historical data, have been docu-
mented by federal environmental protection agencies (e.g., U.S. EPA, 1998a; Swed-
ish EPA, 1994).
References
Bachmann, R.W. 1980. Prediction of total nitrogen in lakes and reservoirs. In
Restoration of Lakes and Inland Waters. EPA 440/5-81-010. U.S. Environmental
Protection Agency, Washington, DC.
Carlson, R.E. 1977. A trophic state index for lakes. Limnol. Oceanogr. 22:361 -9.
Cooke, G.D, E.B. Welch, S.A. Peterson, and RR. Newroth. 1993. Restoration and
Management of Lakes and Reservoirs. Lewis Publishers, Ann Arbor, Ml.
Chapra, S.C. and R.P. Canale. 1991. Long-term phenomenological model of
phosphorus and oxygen for stratified lakes. Water Res. 25:707-15.
Dillon, P. J. and F. H. Rigler. 1974. A test of a simple nutrient budget model predicting
the phosphorus concentration in lake water. J. Fish. Res. Board Can. 31: 1771 -8.
Duarte, C.M. and J. Kalff. 1990. Patterns in the submerged macrophyte biomass of
lakes and the importance of the scale of analysis in the interpretation. Can.J.
Fish. AquatSci. 47:357-63.
162
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CHAPTER S: Predicting Lake Water Quality
Hutchinson, N. J., B. P. Neary, and P. J. Dillon. 1991. Validation and use of Ontario's
trophic status model for establishing lake development guidelines. Lake Reserv.
Manage. 7: 13-23.
Niirnberg, G. K. 1984. The prediction of internal phosphorus load in lakes with
anoxic hypolimnia. Limnol. Oceanogr. 29: 111 -24.
. 1995. Quantifying anoxia in lakes. Limnol. Oceanogr. 40: 1100-1 I.
. 1996. Trophic state of clear and colored, soft- and hardwater lakes with
special consideration of nutrients, anoxia, phytoplankton, and fish. Lake Reserv.
Manage. 12:432-47.
. 1997. Coping with water quality problems due to hypolimnetic anoxia in
Central Ontario Lakes. Water Qual. Res. J. Can. 32: 391 -405.
. 1998. Prediction of annual and seasonal phosphorus concentrations in
stratified and polymictic lakes. Limnol. Oceanogr. 43: 1544-52.
Omernik, J. M., C. M. Rohm, R.A. Lillie, and N. Mesner. 1991. Usefulness of natural
regions for lake management: Analysis of variation among lakes in Northwestern
Wisconsin, USA. Environ. Manage. 15:281 -93.
Reckhow, K. H. and S. C. Chapra. 1983. Engineering Approaches for Lake
Management. Vol. I: Data analysis and empirical modeling. Butterworth, New
York.
Swedish Environmental Protection Agency. 1994. Eutrophication of Soil, Fresh Water
and the Sea. Solna.
U.S. Environmental Protection Agency. 1997. Compendium of Tools for Watershed
Assessment and TMDL Development. EPA-841-B-97-006. Washington, DC.
. I998b. Report of the Federal Advisory Committee on the Total Maximum
Daily Load (TMDL) Program, July 1998. EPA-1OO-R-98-006. Washington, DC.
. I998c. Lake and Reservoir Bioassessment and Biocriteria. EPA-841-98-007.
Washington, DC.
. 1999. Regional Guidance on Submittal Requirements for Lake and Reservoir
Nutrient TMDLs. Office of Ecosystem Protection, New England Region. Boston,
MA.
. 2000a. National Water Quality Inventory. 1998 Report to Congress.
EPA-841 -R-00-001. Off. Water, Washington, DC.
2000b. Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs.
I st ed. EPA-922-BOO-001. Off. Science Tech., Washington, DC.
Walker, W.W. Jr. 1987. Empirical models for predicting eutrophication in
impoundments; Report 4, Phase III: Applications manual. Tech. Rep. E-81-9. U.S.
Army Corps Eng. Waterways Experiment Station, Vicksburg, MS.
Welch, E. B. 1992. Ecological Effects of Waste Water — Applied Limnology and
Pollutant Effects. 2n3 ed. Chapman & Hall, New York.
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Managing Lakes and Reservoirs
164
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CHAPTER 6
Watershed Management
Watershed Management: Principles,
Processes, and Practices
Why Watersheds?
A watershed is the land from which rain and surface water drain toward a central
collector such as a stream, river, or lake (Chapter 2, Ecological Concepts). What
happens as that water runs off the land and into the stream or lake in large part
determines the quality of the lake water. Many lake problems — muddy waters,
aquatic weeds, green scum, poor fishing, and more — reflect the land use and land
cover in the watershed.
Lake management, then, cannot ignore watershed management. In fact, lake
restoration and management should begin in your own backyard, in your commu-
nity — in the watershed. To restore and manage a lake is to work with both the
lake and its watershed.
This chapter defines the lake and its watershed as the management unit and
introduces the concept of watershed planning (see Chapter 8), including a frame-
work for identifying sources of pollutants and watershed management practices
to reduce these sources and their transport into lakes.
A number of watershed management practices have developed over the
years to protect and sustain both land uses and the bodies of water that receive
runoff from the watershed. Known as best management practices, they reduce
runoff, minimize erosion and sedimentation, reduce nutrient and contaminant
loads, and provide better stream habitat for fish and other aquatic organisms. The
last half of this chapter deals specifically with various types of best management
practices.
The importance of the lake and watershed as the management unit cannot
be overemphasized. This manual often uses the term lake system — always keep in
mind that the watershed-lake is the true management unit. While this chapter
emphasizes watershed management practices that are applicable to large water-
sheds with multiple owners and/or organizations controlling the land, these same
principles and practices can also be used by lake homeowners, lake associations,
and lake communities in smaller watersheds.
Best Management
Practices (BMPs):
Methods, measures, or
practices selected by an
agency to meet its nonpoint
source control needs. BMPs
include but are not limited to
structural and nonstructural
controls and operation and
maintenance procedures.
BMPs can be applied before,
during, and after
pollution-producing activities
to reduce or eliminate the
introduction
of pollutants into receiving
waters.
— Federal Register 40
CFR 130.2
165
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Managing Lakes and Reservoirs
Pollution, as defined by the Clean
Water Act and current regulations, is
human-made or human-induced
alteration of the chemical, physical,
biological, and radiological integrity
of a water body. A pollutant, as
defined by the Clean Water Act and
current regulations, is dredged spoil,
solid waste, incinerator residue,
sewage, garbage, sewage sludge,
munitions, chemical wastes,
biological materials, radioactive
materials, heat, wrecked or
discarded equipment, rock, sand,
cellar dirt, and industrial,
municipal, and agricultural waste
discharged into water. For
example, pollution would be the
loss or destruction of a streambank
or lakeshore habitat. Sediment or
phosphorus discharged into a water
body would be pollutants.
The Lake/Watershed Relationship—The
Management Unit
The lake and its watershed are inseparably linked — the lake or reservoir does
not exist without its watershed (see Chapter 2). The management unit, then, is
the lake and its watershed. It is not cost effective to manage the lake if the prob-
lem arises in the watershed or to manage watershed activities that have no effect
on lake quality. You must manage the lake and its watershed.
A problem in a lake or reservoir is often the symptom of poor watershed
management. As Chapter 2 points out, the watershed contributes both the water
required to maintain a lake or stream and most of the pollutants that enter the
lake. Obviously, addressing the symptoms of the problem without correcting the
source and cause of the problem is not only shortsighted — it doesn't work for
lakes!
Understanding the lake/watershed relationship requires some knowledge
about the myriad of activities and land uses in the watershed. Such pursuits as
farming, gardening and landscaping, logging, construction and development, and
their resulting land cover — pastures, fields, forests, factories, subdivisions, and
parking lots — can significantly affect water quantity and quality (see Fig. 6-1 for
examples of watershed activities and uses that link the lake with its surroundings).
While many of these activities occur in every watershed, large or small, the rela-
tive importance of each can vary from watershed to watershed.
Potential Sources of Pollutioiili§iiig|i
Figure 6-1.—Watershed activities and land uses that contribute to both point
and nonpoint source pollution of lakes and reservoirs.
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CHAPTER 6: Watershed Management
Another part of this management unit — groundwater — contributes flow
and dissolved constituents such as nutrients, contaminants, and minerals. Ground-
water can comprise the major part of the flow during dry periods (Fig. 6-1).
A primary objective of watershed management is to maintain the integrity of
the major hydrological pathways (water flow) that people can affect. So you want
to focus on how people have changed the landscape (e.g., urbanization) in a way
that introduces materials and contaminants into the hydrological pathways and/or
reduces the function and assimilative capacity of these pathways (e.g., loss of
wetlands, streambank cover, trees, and shrubs). Altering these hydrological
pathways harms the amount, timing, and quality of water that enters streams and
lakes. Addressing these questions before beginning a watershed management pro-
cess will lead to more realistic lake restoration or management goals.
Where Pollutants Come From
Pollutants, such as sediments, organic matter, and nutrients like nitrogen and
phosphorus, enter a lake either from point or nonpoint sources in the watershed
(Fig. 6-1).
^ Point sources come from a distinct source such as a wastewater
(sewage) treatment plant, industrial facility, or similar source that dis-
charges through a pipe or similar outlet (Fig. 6-1). You can identify them by
tracing the discharge back to its specific source.
Point sources are usually controlled by state or federal permits such
as the National Pollutant Discharge Elimination System (NPDES). The
NPDES permit program has significantly reduced point source discharges
of pollutants since 1972 (the year the Clean Water Act was passed) —
and eliminated point sources as the major source of water pollutants in
many watersheds.
By the mid-1990s, stormwater had also been designated as a point
source (the portion discharged to water bodies through storm drains)
and is, in most instances, subject to federal or state permit requirements.
^ Nonpoint sources, in contrast, do not originate from a pipe or sin-
gle source. Nonpoint source pollution generally results from precipitation,
land runoff, infiltration, drainage, seepage, hydrologic modification, or at-
mospheric deposition. As runoff from rainfall or snowmelt moves, it picks
up and transports soil, nutrients, organic matter, toxins (herbicides, insecti-
cides, metals), and other pollutants and carries them to lakes and streams
(and sometimes, groundwater). From a regulatory standpoint, nonpoint
sources are sources that are not defined by statute as point sources.
Water running off a lawn, driveway, or road during a rain is a common
sight — that's nonpoint source runoff (Fig. 6-1). It happens everyplace in
the watershed, but some land uses such as agriculture, construction, and
city streets contribute more nonpoint source pollutants than other land
uses such as forests and land covered by vegetation.
It is not always easy to distinguish a point source from a nonpoint
source. In this chapter, point sources will be defined as factories, other in-
dustrial concerns, municipal wastewater treatment plants, and similar facili-
ties that discharge wastewater through a pipe. In addition, runoff from
construction sites greater than one acre is now regulated as a point source.
Point source: any
discernible, confined, and
discrete conveyance,
including but not limited to
any pipe, ditch, channel,
tunnel, conduit, well, discrete
fissure, container, rolling
stock, concentrated animal
feeding operation, or vessel
or other floating craft from
which pollutants are or may
be discharged. This term
does not include agricultural
stormwater discharges and
return flows from irrigated
agriculture.
—as defined in Section
502 (14) of the Water
Quality Act of 1987
Nonpoint sources:
sources not defined by statute
as point sources; include
return flow from irrigated
agriculture, other agricultural
and silvicultural runoff and
infiltration, urban runoff from
small or unsewered urban
areas, flow from abandoned
mines, and hydrologic
modification.
— regulatory definition
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Managing Lakes and Reservoirs
Nonpoint sources will include all other types of pollutant loadings to
the lake or stream, including lawns, driveways, subdivision roads, small con-
struction sites, agricultural areas, forests, abandoned mine sites, and air-
borne or atmospheric contributions (Fig. 6-1).
Tfie Grow/iig Trend for Watershed
Planning and Management
More and more, communities and agencies are emphasizing watershed planning
and management, and finding assistance in various aspects from many federal
and state agencies. EPA's website (Watershed Information Network at
www.epa.gov/win/) offers information and links for most government programs.
WIN users can surf their own watershed for information, and also access many
other websites that focus on other watershed management programs through-
out the country.
Watershed management starts with a plan — a road map defining where you
are now, where you want to go, and how you are going to get there.
Watershed Management Plans
Without a plan, watershed management activities will be disorganized and ineffec-
tive (see Chapter 8 for more detail on formulating effective lake management
plans). The number of local watershed planning organizations is increasing across
the country as communities realize the value of a watershed action plan. Water-
shed planning helps people understand the relationship between the materials
that enter the lake from the watershed and the water quality values that need to
be protected (Fig. 6-2).
Get
Organized
Identify Problems
and Opportunities
Monitor, Evaluate
and Adapt
Develop
Management Plan
Implement Plan
with Stakeholders
Figure 6-2.—Generalized •watershed planning process.
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CHAPTER 6: Watershed Management
The watershed planning process is the best approach for relating science,
policy, and public participation to water resources management. As you begin
building public support for your watershed planning process, include everyone
who may have a significant impact on conditions in the lake — and those who
might be affected by its restoration.
Keep in mind four important points about the process:
• The watershed plan does not need to be completed before activities
can begin; rather, it guides the watershed group by mapping a strategy
for improving or protecting the watershed.
• The planning process does not proceed in just one direction — you
may have several activities going on simultaneously. What you learn in
one step may cause the watershed group to revisit a decision made in
a previous step.
• The watershed planning process and written plan are supporting, not
prescriptive, tools. Be flexible.
• The watershed management plan is the beginning, not the end, of the
management cycle (Fig. 6-2).
Some of the activities associated with each step in this management cycle
follow.
Get Organized
• Recruit stakeholders and establish the partnership.
• Define the watershed.
• Create a mission statement.
• Establish points of contact, a decision process, and organizational
structure.
• Facilitate information-sharing among participants.
• Document the process.
Identify Problems and Opportunities
• Collect information on the human and ecological features affecting
water quality.
• Identify the predisturbance or reference conditions for the lake.
• Define objectives for water quality and other lake uses.
• Define the problems (to the extent that available data allow).
• Develop problem/opportunity statements for the watershed.
Develop Management Plan
• Define the future condition desired for the lake/reservoir.
• Define restoration goals and objectives.
• Identify restoration constraints and issues.
• Set priorities.
• Evaluate potential solutions for identified problems and objectives.
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Managing Lakes and Reservoirs
• Design restoration project selected to meet objectives.
• Identify measures of success for restoration project.
• Create an action plan, with schedules, task assignments, and a funding
strategy.
Implement the Plan with Stakeholders
• Secure funding.
• Implement plan.
Monitor, Evaluate, and Adapt
• Monitor the restoration and evaluate progress.
• Revisit the management plan and make adjustments where needed.
Communication is essential because a watershed approach requires the in-
formed participation of its stakeholders. To use your resources wisely you need
to target objectives the stakeholders support. Stakeholders must participate at
decision points; this ensures that final decisions will have sufficient support to suc-
ceed. Written watershed plans reflect the activities and decisions of the water-
shed planning group, so the planning process and its associated document should
be designed to meet their goals.
Table 6-1 is a model outline of a watershed action plan included in A Guide to
Developing Local Watershed Action Plans in Ohio (Ohio EPA, 1997). This format is a
good starting point for designing a watershed plan, but you'll probably revise it to
focus on your own lake's problems (the original has already been changed to add
issues such as habitat and invasive species).
TMDLs - A Watershed
Management Tool
Although not specifically designed for this purpose, the Total Maximum Daily
Load (TMDL) Program provides an excellent framework for watershed manage-
ment that can help you develop and implement a Watershed Management Plan
(see www.epa.gov/owow/tmdl). Established by the original Clean Water Act in
1972, a TMDL calculates the maximum amount of a pollutant that a water body
can receive and still meet water quality standards — a legal way of protecting that
water body's desired uses. While the TMDL Program has become controversial
and litigious, its overall goals are ultimately what we seek in watershed manage-
ment:
• Identify the desired uses for the lake.
• Determine how much total loading of a pollutant(s) the lake can
receive and still provide the desired uses.
• Assess how much of the pollutant load is coming from
—» natural background,
-> point sources, and
nonpoint sources.
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CHAPTER 6; Watershed Management
Table 6-1 .-Ohio EPA template for a local watershed action plan (Ohio iPA, 1997).
1. Define the Watershed
1.1 Name, size, administrative boundaries of watershed
1.2 Geographic locators; USGS and state 305(b) identification numbers
1.3 Background/historical information on previous watershed protection and
management activities, including previous planning documents
1.4 Purpose of the plan, a statement on the need for watershed action planning
and why the plan was prepared
1.5 Scope and limitations of the plan
1.6 Who was involved in preparing the plan
1.7 Outline of the plan's content
2. Describe the Watershed
2.1 Natural features/characteristics of water source
2.1.1 Special values: cultural, geologic, species
2.1.2 Hydrology
2.1.3 Land uses
• point sources
• nonpoint sources
2.2 Water quality
2.2.1 Use designations/attainment
2.2.2 Causes of non-attainment
3. Identify Problems
3.1 Identify sources of contaminants and quantify loads
3.2 Evaluate habitat conditions
3.3 Assess status of species of interest
4. Document Planned Activities
4.1 List goals
4.2 Describe specific management objectives (incorporate solutions) and actions
4.3 Link actions to individuals, committees, or organizations
4.4 Match actions with indicators or measures
4.5 Outline activities timeline
4.6 Describe adaptive management methods
• If the incoming load is greater than the maximum load the lake can
handle, then reduce the load and allocate these reductions among the
sources.
• If the incoming load is less than the maximum load the lake can
handle, protect it to ensure the desired uses will continue.
Using the desired uses of the lake and the applicable water quality standards
identified in the Watershed Management Plan as a base, you can review existing
data to find out if they are being attained. In addition, you can determine the pol-
lutant loading for constituents of concern. An important part of the TMDL is to
learn the relative contributions of pollutants from natural sources, point sources,
and nonpoint sources.
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Managing Lakes and Reservoirs
GIS: A Useful Watershed
Evaluation Tool
Geographic Information
Systems (GIS) are useful
watershed evaluation tools
because they can be used to
display what the land uses are
in the watershed, and to
estimate loads from these land
uses. GIS can show the location
of different land uses around
the lakes and receiving streams
(Fig 6-3). The location of land
use affects the loading to the
system. Generally, forest,
riparian zones, and grassed
areas along the streambanks
and lake shoreline result in
lower loadings and better water
quality than other land uses
near the water body. Formulas
or equations have been
developed describing sediment,
nutrient, and organic loading
from different types of land
uses. The GIS can use these
formulas with the extent of the
land use to estimate the
loadings to the lake. The GIS
can also be used to evaluate
the reduction in loading that
might occur if best management
practices were implemented in
the watershed.
Lakes & TMDLs
Of a number of Clean Lakes Restoration projects Washington state has submitted to
EPA as TMDLs, some have been approved and others have been labeled incomplete
'! — either because: ;
* Eutrophication problems were not thoroughly documented; or
• The TMDL goal was established without numeric water quality criteria.
Two examples:
Lake Fenwick (approved) — EPA approved this Phase 1 diagnostic/feasibility
study with a Phase 2 restoration proposal based on clear identification of the
phosphorus load needed to achieve a TMDL goal of aesthetic enjoyment acceptable
to the lake user community. Probable funding of the Phase 2 project and ordinances
adopted by the City of Kent for stormwater runoff also provided reasonable
assurance that the TMDL goals will be met eventually.
Lake Erie (incomplete) — This lake restoration had completed both Phase 1 and
Phase 2, and was in Phase 3 (evaluation stage) when EPA determined it to be an
incomplete TMDL — primarily because the Phase 1 study did not thoroughly
document the eutrophication problems and associate them with a TMDL goal. To
qualify as a TMDL, a quantitative analysis must demonstrate that the goals
established for the TMDL will meet the narrative standard for support of a
designated use (e.g., phosphorus levels needed for aesthetic enjoyment).
SI Communities
O Johnson Hols
A/ South Fork Little Red KM
LULC South ForK little Red Sub Basin
I CROP AND PASTURE
3 FOREST
1 UNDEFINED
I URBAN AND OTHER
JWATER
I WETLAND
?UtBeRedRf-1
] uttta Red Waterehed
| I Counties
r~i State
Figure 6-3.—Sample of a GIS.
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CHAPTER 6: Watershed Management
Background Sources
For most constituents, including sediment, nitrogen, phosphorus, organic matter,
and any naturally occurring metals (iron, manganese, zinc, copper, etc.), naturally
occurring sources in the watershed contribute them to the receiving streams or
lake (Fig. 6-1). For some lakes, the natural background loads may not permit
some desired lake uses to be achieved. For example, organic loading from rela-
tively undisturbed, forested watersheds result in zero dissolved oxygen in the
bottoms of many southern lakes and reservoirs — a natural condition in this part
of the country. This lack of oxygen in the bottom waters, however, means that
these southern reservoirs won't support a coldwater fishery, which might be a
desired use for the lake.
Some of the approaches for estimating background conditions include:
• Use lakes or streams with relatively undisturbed watersheds as a
reference for what could reasonably be attained in the watershed.
• Use some of the models described in Chapter 5 to estimate
constituent loads assuming no point or nonpoint sources.
• Use first principles (i.e., the fundamental relationships from which all
others are derived) to estimate the erosion and transport of
constituents based on the soils and geology in the watershed.
Point Sources
Because point sources are controlled under the National Pollutant Discharge
Elimination System, information on the volume of discharge and constituent con-
centrations in the discharge can be obtained from EPA and the states. Point
source loadings can be estimated by summing the point source discharges for
both municipalities and industries in the watershed. Guidance manuals on how to
estimate point source loads are listed on the EPA TMDL web site (www.epa.gov/
owow/tmdl).
Nonpoint Sources
Nonpoint sources are both natural and human-influenced (Fig. 6-1). Estimating
natural background loads was discussed previously. Human-induced loads can be
estimated based on sampling or monitoring data or by using some of the model-
ing and estimation approaches discussed in Chapter 5. Once these estimates are
obtained, the natural background load can be subtracted to determine how much
of the loading comes from just human activities in the watershed, such as grazing
cattle in pastures, adding fertilizers to crops, mining, timbering, building roads and
highways, and similar human disturbances (Fig. 6-1). Again, guidance and manuals
on how to estimate nonpoint source loads can be found on the EPA TMDL
website, which also has links to other agency sites that focus on specific land-use
types such as agriculture or silviculture.
Total Maximum Daily Loads
A total load for the pollutant(s) of concern can be estimated by adding:
Total Load = Natural Background Load + Point Source Load + Nonpoint Source Load
Compare this Total Load to the Total Maximum Daily Load that the lake can han-
dle and still allow desired lake uses. If the Total Load exceeds the TMDL, then
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Managing Lakes and Reservoirs
L-COS}
cosystem Analysis Is
used particularly in
whereas Smart Growth
is an approach to
minimize the effects of
urban sprawl on
aquatic ecosytems.
Ecosystem: a system of
interrelated organisms and
their physical-chemical
environment. In this manual,
the ecosystem is usually
defined to include the lake
and its watershed.
point and nonpoint source loads need to be allocated to the TMDL Caution:
you must allow a margin of safety in comparing the TMDL with the Total Load,
just in case there were some unknowns in the estimates. This margin of safety
should ensure that reducing pollutant loads will improve water quality.
If the Total Load is less than the TMDL, then watershed management prac-
tices and actions need to focus on protecting the watershed and lake from ex-
ceeding the TMDL.
In either case, the TMDL can guide watershed management plans and prac-
tices to achieve the lake uses desired by the community. See EPA's TMDL web site
for examples of several approved TMDLs for pollutants such as bacteria, turbidity,
sediment, nitrogen, and phosphorus.
Other useful tools for assessing watershed conditions include Ecosystem
Analysis and Smart Growth. Ecosystem Analysis is used particularly in western
watersheds, whereas Smart Growth is an approach to minimize the effects of ur-
ban sprawl on aquatic ecosystems.
Ecosystem Analysis at the Watershed Scale
Ecosystem analysis is a procedure frequently used by many western U.S. resource
management agencies such as Game and Fish agencies or the Bureau of Land Man-
agement (B.M.) to characterize the human, aquatic, riparian, and terrestrial features,
conditions, processes, and interactions (collectively referred to as "ecosystem ele-
ments") within a watershed (Intergovernmental Advisory Committee, 1995).
Watershed analyses address:
• Erosion;
• Hydrology or water flow;
• Vegetation or land cover in the watershed;
• Stream channel habitat;
• Water quality;
• Biological organisms or species and habitats; and
• Human uses.
There are several forms of watershed analysis, but each is structured around a
series of key questions which, if answered, provide a model of landscape and eco-
system function, disturbance history, and current and potential future conditions.
Watershed analysis supports decision-making priorities, because it generates
the information required to make informed choices about how land uses will
work in the watershed — within its ecoregion (Montgomery et al. 1995).
Watershed analysis is based on a six-step process that:
• Characterizes the watershed by identifying the dominant physical,
biological, and human processes or features that affect ecosystem
functions or conditions — and identifies primary ecosystem elements
that require more detailed analysis;
• Identifies issues and key questions to focus the analysis on the key
elements of the ecosystem most relevant to the management
questions and objectives, human values, or resource conditions;
Describes the current conditions of ecosystem elements;
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CHAPTER 6: Watershed Management
• Describes reference conditions for ecosystem elements or how
ecological conditions have changed over time;
• Synthesizes information by comparing existing and reference
conditions and determining the capability of the system to achieve key
management plan objectives; and
• Describes management plan recommendations that are responsive to
watershed processes identified in the analysis.
This watershed analysis process has been the starting point for many water-
shed management forums for lakes in the western United States. Several land
management agencies there have joined with local communities and Resource
Conservation Districts to conduct watershed analyses as part of emerging water-
shed partnerships. The Northwest Forest Plan has encouraged watershed analy-
sis, based on the experience of the Forest Service and BLM with the northern
spotted owl (USDA, 1994).
For additional guidance on watershed analysis, see U.S. EPA (2000); www.
epa.gov/owow/watershed/wacademy/wam/.
Smart Growth — An Approach to Urban Watershed
Planning and Management
Smart Growth is a phrase to capture a new way of thinking about land develop-
ment, urban renewal, and economic growth. Smart Growth is a holistic planning
approach that factors in many considerations before making changes or develop-
ing solutions to problems. It is related to watershed management because it at-
tempts to assess the cumulative effects of land uses and changes to the
environment. And, like watershed management, it depends on information ex-
change and consensus among people, communities, stakeholders, and local, state,
and federal agencies to make decisions that benefit the entire system in which a
community lives.
Both Smart Growth and watershed-based approaches can be used to foster
consensus, to develop objectives, and ultimately, to make positive impacts on the
quality of the land on which we live — and the water we use.
Development replaces natural vegetated land cover with roads, parking lots,
driveways, sidewalks, and rooftops. These surfaces are impermeable to rainwater
and tend to increase surface water runoff that then carries pollutants directly to
streams, rivers, and lakes. A I -acre parking lot generates 16 times more polluted
runoff than a I -acre meadow.
Examples of Smart Growth that parallel watershed planning practices include:
• Encouraging "best development practices" such as designing parking
lots with natural buffers to capture runoff, and developments with
common open spaces, parks, trails, and less impervious surfaces;
• Increasing incentives for revitalizing city centers and brownfields (areas
degraded by past industrial use) for reuse rather than expanding into
farmland and open spaces, thereby reducing suburban sprawl;
• Building communities that depend less on the automobile for getting
around and more on public transit (which means increasing support
for mass transit);
A
1 -acre parking lot
generates 16 times more
polluted runoff than a
1-acre meadow.
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Managing Lakes and Reservoirs
• Changing zoning to encourage conservation of natural areas; and
• Increasing use of building and landscaping practices that create riparian
buffer zones.
Further information can be found at www.smartgrowth.org.
From Planning to Practice
With the Watershed Management Plan developed, information on point and
nonpoint source loading, and an estimate of the TMDL, what management prac-
tices can you use either to reduce loading from point and nonpoint sources or to
protect the lake from increases in these loadings?
The next section discusses watershed management practices that can be
used to control point source loads; and the following section, best management
practices (BMPs) to control nonpoint source loads. Neither section tries to de-
scribe all control practices, but rather to illustrate the types of control techniques
and practices that are available.
Please see Appendix 6-A for an extensive list of links and references to in-
formation that can be used in watershed management. And contact your local
and state agencies for more information.
Watershed Management Practices:
Point Sources
Wastewater usually comes from a point source; it's discharged through pipes by
industrial and municipal treatment plants. And even though it's treated to remove
most pollutants, it still may contain organic matter, bacteria, nutrients, toxic and
other substances — most of which can be extremely harmful to lake water qual-
ity.
For example, when incoming water carries a great deal of organic matter, the
bacteria that decompose it may consume so much of the lake's dissolved oxygen
in the process that the supply can't keep up with the demand. This is particularly
dangerous in lakes whose bottom waters are already anoxic (see Chapter 2). The
result: without oxygen, you have fishkills, odors, and noxious conditions. In addi-
tion, as organic matter decomposes, it can also contribute nutrients to the water.
Although stressful enough by itself, the combination of high, oxygen-
demanding organic loads and low dissolved oxygen levels compounds when it co-
incides with the peak growing season for algae and aquatic plants. The incoming
nutrients fertilize the algae and plants, which not only grow excessively but fur-
ther deplete the oxygen as they die and decompose.
Most wastewater treatment plants discharge at low rates: over 75 percent of
all publicly owned treatment plants discharge less than I million gallons per day
(mgd). Sewage treatment ponds or lagoons — the most common type of
wastewater treatment •— typically have discharge rates less than I mgd. But low
discharge rates do not translate into insignificant effects on lakes and streams.
At just 10 to 50 parts per billion dig/L) total phosphorus concentration in
the water, some lakes may develop algal blooms, murkiness, and other problems.
The average total phosphorus concentration of wastewater treatment plant dis-
charges is about 100 times greater than this.
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CHAPTER 6: Watershed Management
In many streams, wastewater discharges may dominate streamflow during
the dry summer period when the stream's total flow is low. Also, at the higher
summertime water temperatures, water cannot hold as much dissolved oxygen
as it does during the cooler periods of the year.
Contact your state water pollution control agency for information on per-
mitted facilities discharging into your lake or into streams entering your lake.
Wastewater Treatment
If point sources are important contributors of organic matter, bacteria, nutrients,
or toxic pollutants, good wastewater treatment will provide critical protection
for your lake. The better the system is at removing pollutants, the fewer algal
blooms, aquatic weeds, and odors will occur in the lake. Regardless of the treat-
ment system, however, all treatment systems require proper design, opera-
tion, and maintenance. These requirements vary among treatment systems, but
no system can be installed and then ignored. Systems must be maintained.
Several approaches for treating point source discharges are briefly described
in this section, beginning with municipal treatment systems. In general, it is more
efficient and cost effective to collect wastewater from homes and industries and
treat it in one large facility than to have individual septic systems or treatment fa-
cilities. In some cases, however, smaller treatment systems are required. A site,
soil, and TMDL assessment are necessary before the final decisions are made. In
addition to the descriptions that follow, more information on any of these treat-
ment systems can be found in Appendix 6-A or on the EPA Office of Wastewater
Management website (www.epa.gov/owm).
Municipal Systems
Typical waste treatment systems for larger cities and municipalities are conven-
tional sewer systems piped to treatment facilities. These large treatment plants
include systems such as activated sludge, biofilters, contact stabilization, sequenc-
ing batch reactors, land treatment, and large-scale lagoons. Most municipal treat-
ment systems have both primary and secondary treatment. Some treatment
systems are even more advanced and also have tertiary treatment
v Primary wcrsfewafer treatment uses screens and sedimenta-
tion (settling) to remove the larger organic solids. But dissolved organic
matter can still use considerable oxygen, so secondary treatment is used
to reduce this oxygen demand before the wastewater is discharged into
the lake or stream.
v Secondary treatment uses biological and chemical processes to re-
move 80 to 95 percent of the organic matter (Fig. 6-4). Primary and
secondary treatment, however, do not significantly reduce dissolved phos-
phorus concentrations (Table 6-2).
• Total phosphorus concentrations in untreated domestic wastewater
are reduced about 5 percent by primary treatment and about 10 to 15
percent by secondary treatment.
• Both primary and secondary treatment remove much more nitrogen:
about 40 percent with primary treatment; 60 percent with secondary
treatment
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Managing Lakes and Reservoirs
Activated Sludge
Raw
Wastewater
Secondary Treatment
Treated
Outflow
Figure 6-4.—Typical secondary treatment system with primary settling of water,
chemical or biological treatment, and additional settling and disinfection before
discharge.
Table 6-2.— Treatment removal efficiencies for wastewater treatment systems.
CONSTITUENT
Suspended Solids
Biological Oxygen Demand
Ammonia-Nitrogen
Total Phosphorus
TREATMENT CATEGORY
PRIMARY
50 _ 70%
20 - 40%
—
-5%
SECONDARY
85 - 95%
85 - 95%
40 - 60%
10- 15%
TERTIARY
—
—
~ 90%
75 - 90%
This means, however, that about half the total nitrogen and almost all the to-
tal phosphorus stay in the wastewater after it's treated at the second level.
v Another /eve/ of treatment — tertiary or advanced
treatment — is required to significantly reduce nutrient concentra-
tions in wastewater. This level of treatment used to be relatively expensive
so it was not used to the same extent as secondary treatment. However,
more cost-effective tertiary treatment systems, including constructed
wetlands, ammonia stripping, multimedia filtration, and carbon adsorption
are becoming available.
Normally, large municipal treatment systems are not suited to small commu-
nities. These complicated mechanical systems require skilled operators to run
and maintain and typically use large amounts of energy — they're also costly for
small communities to build. Fortunately, alternative treatments now exist for
small communities and lake homeowners.
Small Community Systems
Several small-scale, simple, and reliable central treatment systems are suitable for
the lake homeowner or lake association (Table 6-3; Fig. 6-5a,b). All of these well-
established methods provide secondary or better levels of treatment at less cost
to build and run than the larger municipal treatment plants. They also use less en-
ergy and are easier to operate and maintain.
If you're starting to plan a wastewater project, select an engineer who has
experience with these small community technologies. Check with a local contrac-
178
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CHAPTER 6: Watershed Management
tor who specializes in wastewater treatment, and with your health department,
water pollution control agency, and EPA. You will need permits to discharge and
the type of system and permit will vary by municipality, county, and state. The
EPA Office of Wastewater Management has a specific program for small commu-
nities. The EPA "Small Communities Team" partners with community organiza-
tions to provide programs for technical assistance, financial assistance, and
education and training (see www.epa.gov/own/smallc/) and Appendix 6-A.
Table 6-3.— Examples of small-scale treatment plants and designs.
EXAMPLE
Septic Tank
Septic Tank Mound
System
Septic Tank-Sand Filter
Facultative Lagoon
Oxidation Ditch
Trickling Filter
Overland Flow
Treatment
Spray Irrigation
Treatment Wetlands
DESCRIPTIVE NOTES
A septic tank followed by a soil absorption bed is the
traditional on-site system for the treatment and disposal of
domestic wastewater from individual households or
establishments. The system consists of a buried tank where
wastewater is collected and scum, grease, and settleable solids
are removed by gravity and a subsurface drainage system
where wastewater percolates into the soil.
Can be used as an alternative to the conventional septic
tank-soil absorption system in areas where soil conditions
preclude the use of subsurface trenches or seepage beds.
Surface discharge of septic tank effluent. Can be used as an
alternative to the conventional soil absorption system in areas
where subsurface disposal contains an intermediate layer of
sand as filtering material and under drains for carrying off the
filtered sewage.
An intermediate depth (3 to 8 feet) pond in which the
wastewater is stratified into three zones. These zones consist of
an anaerobic bottom layer, an aerobic surface layer, and an
intermediate zone.
An activated sludge biological treatment process. Typical
oxidation ditch treatment systems consist of a single or closed
loop channel 4 to 6 feet deep, with 45° sloping sidewalls.
Some form of preliminary treatment such as screening or
removing normally precedes the process. After pretreatment,
the wastewater is aerated in the ditch using mechanical
aerators that are mounted across the channel.
The process consists of a fixed bed of rock media over which
wastewater is applied for aerobic biological treatment (Fig.
6-5a). Slimes form on the rocks and treat the wastewater. The
treated wastewater is collected by an underdrain system.
Wastewater is applied by gravity flow to vegetated soils that
are slow to moderate in permeability and is treated as it travels
through the soil matrix by filtration, adsorption, ion exchange,
precipitation, microbial action, and plant uptake (Fig. 6-5b).
An underdrainage system recovers the effluent, controls
groundwater, or minimizes trespass of wastewater onto
adjoining property by horizontal subsurface flow.
The wastewater is sprayed on crops or ground cover and the
water is treated as it percolates through the soil. An under
drainage system functions as with Overland Flow.
Wetlands are constructed specifically to function as wastewater
treatment systems. In the wetland system, plants and soils
remove nutrients for growth, provide a surface for
micro-organisms and bacteria to break down waste, and
promote settling of solids. Treatment wetlands serve as tertiary
treatment for many communities.
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Managing Lakes and Reservoirs
Figure 6-5a.—Trickling filter works by trickling wastewater over layers of rocks. Bac-
teria growing on the rocks break the waste down.
Figure 6-5b.—Overland flow of wastewater removes organic matter through soil
bacteria, phosphorus by sorption to soils, and nitrogen through plant uptake.
SPRAY APPLICATION
EVAPOTRANSPIRATION
GRASS AND VEGETATIVE LITTER
RUNOFF COUECTfON
**• SHEET FLOW
On-lot Septic Systems
The septic tank and drain field (Fig. 6-6) comprise the most common of these in-
dividual home sewage disposal systems. The septic tank traps solids, oil, and
grease that could clog the drain field, storing sludge (solids that settle to the bot-
tom), scum, grease, and floating solids until they can be removed during regular
septic tank cleaning (every three to five years, depending on use). Specific recom-
mendations for pumping out the tank can be obtained from county or state agen-
cies. The wastewater that remains flows out of the septic tank and into the drain
field where it seeps into the soil. The soil filters this partially treated sewage, and
bacteria that began decomposing the waste in the tank continue to work. Charac-
teristics of septic tanks are given in Table 6-4.
As the wastewater flows through the drain field, phosphorus may be ab-
sorbed by soil particles, and biological processes reduce the nitrogen. Bacterial
decomposition in the drain field reduces the oxygen demand of this wastewater
before it enters the lake or groundwater.
180
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CHAPTER 6: Watershed Management
Inspection
inlet
»
3Q
Liquid
Sludge
Building paper
^
« \t t 4 i • i
JTT II
Septic tank cross section
* >••••«»•«•
• Disposal field section.
Figure 6-6.—Typical home septic system works well in many settings, but should not
be used near lakes. Improper operations or failure will pollute the lake.
Table 6-4.— Characteristics of septic tanks.
CRITERIA
1 . Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
Most widely used method of on-lot domestic waste disposal;
used by almost one-third of the U.S. population.
Used primarily in rural and suburban areas. Properly
designed and installed systems require a minimum of
maintenance and can operate in all climates.
Reliable, if properly designed and managed in appropriate
soils.
Properly designed, constructed, and operated septic tank
systems are efficient and economical. System life may equal
or exceed 20 years.
Sludge and scum in tank must be removed every 3 to 5 years,
depending on soil and site conditions, the ability of the soil to
absorb liquid, depth to groundwater, nature of and depth to
bedrock, seasonal flooding, and distance to well or surface
water.
May increase nitrates and other contaminants in groundwater
when the soil does not remove them. Soil may also clog on
the surface with potential health problems.
Oeptic systems are
used by almost one-third
of the U.S. population. 1
181
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Managing Lakes and Reservoirs
Some bacteria also convert nitrogen as ammonia to nitrate in the drain field,
which tends to move with the water, eventually entering the lake. Ammonia and
nitrate are fertilizers, and can encourage algal growth under the right conditions.
If they're properly designed and maintained, septic systems can remove or-
ganic matter, bacteria, and nutrients. They only work, however, in good site condi-
tions — which don't exist on all lakeside lots. Conditions that interfere with
proper septic system function:
• Unsuitable soils (you've heard the saying: they don't perc);
• High water tables;
• Steep slopes; and,
• The human element, as reflected in poor design or improper use.
^ Soil plays a key role in the septic system. Tightly bound and poorly
drained soil types (clays) are not effective filters. At the other extreme,
gravel is also a poor filter because the wastewater drains through it too
rapidly to be adequately treated.
Treatment also diminishes when the soil is too wet. Septic systems
depend upon good contact between the wastewater and relatively dry soil
particles so that the soil can absorb nutrients well. Soils that drain very
slowly may be chronically saturated and the system, therefore, inoperative
much of the time.
In a poorly drained soil, the wastewater is also likely to surface and
run directly to the lake. A streak of bright green grass growing over the
drain field indicates that wastewater nutrients are fertilizing the lawn on
the way up.
v High groundwater tables can also prevent treatment by periodi-
cally flooding the drain system.
^ Steep slopes cause either rapid flow-through or surfacing of waste-
water.
Frequently, a septic problem can be traced to improper use, commonly aris-
ing from:
• Too small a tank;
• An inadequate drain field;
• Serving more people than the system was designed for;
• Using improper washing products;
• Following a poor septic tank maintenance schedule; or
• Using a garbage disposal, which overloads the system with fine solids.
Check with your health department or environmental agency for a reference
on the functioning and design of septic systems. EPA also has a design manual for
on-site wastewater treatment and disposal systems (U.S. EPA, 1980). In addition,
many county extension offices have information on septic system installation and
maintenance, including the Home*A*Syst software program.
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CHAPTER 6: Watershed Management
1. Wastewater
from home drains
to first septic tank
where heavy solid
waste drops out.
It usually stays here
for about a day.
2. Filtered
wastewater
drains to
second tank
where more
solids drop out.
This takes
about another
day.
3. Wastewater then
drains to a wetlands
area where bacteria
break it down even
further and cattails,
rushes, or reed
grasses take up the
nutrients for growth.
About a seven-day
process
A constructed wetland is about 24 to 30 inches
deep. It contains a top layer of pea gravel, a
second layer of coarse gravel, and a plastic
liner at the bottom.
4. Treated wastewater
then drains to a final
basin where it evaporates
and is discharged into a
stream.
Figure 6-7.—Wetland treatment system.
Natural Treatments
Natural areas such as wetlands have occasionally been constructed around a lake
to provide advanced wastewater treatment. Such treatment is typically used
when conventional wastewater treatment cannot produce the lower nutrient
concentrations needed. Wetlands can function as a biological filter to remove silt,
organic matter, and nutrients from an inflowing stream, keep it out of the lake, and
improve lake quality (Fig. 6-7). But, wetlands, under some conditions, can also con-
tribute organic matter and nutrients to lakes. Nutrients released from wetlands
can fertilize algal growth and contribute to lake problems.
Whether a wetland serves as a source or filter for nutrients and organic
matter needs to be studied further. EPA has a Design Manual for Constructed Wet-
lands for Wastewater Treatment Systems (U.S. EPA, 1988). Additional information
can be found on the EPA website (www.epa.gov/owm).
Watershed Management Practices:
Nonpoint Sources
Nonpoint sources of pollution became apparent as municipal and industrial point
sources were controlled. Point source controls have clearly made a difference in
improving water quality since the passage of the Clean Water Act (1972), but wa-
ter quality has not improved as much as expected.
Why? Point sources, long the major water polluter, had masked nonpoint
source pollution problems. Once point source loadings declined, the impact of
nonpoint sources became apparent.
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Managing Lakes and Reservoirs
Only by stepping away from the-narrow viewpoint that point sources caused
nearly all water quality problems were water quality managers able to see the lake
and watershed as an integrated system affected by diverse sources of pollutants.
By approaching the management of lakes and streams from a broader per-
spective, water managers and scientists found that in many systems nonpoint
sources contributed as much or more than point sources — particularly sedi-
ment, organic matter, and nutrients. Although nonpoint source nutrient concen-
trations were less than those in a point source, the total load (concentration
times flow) can far exceed that contributed by point sources.
To determine the relative importance of local versus distant sources of nu-
trients and sediments to a lake, compare the watershed area with that of the lake.
For example, if there are 100 acres in the watershed and the surface area of the
lake is 100 acres, then the watershed to lake surface area ratio is I to I (1:1).
In small watersheds, where the surface area of the lake is roughly equal to
the surface area of the watershed (i.e., an approximate 1:1 ratio between the lake
surface area and the size of the watershed), the local sources of organic matter
and nutrients — such as septic systems and runoff from lawns and gardens —
might contribute the most pollutants to the lake. Construction can also be a sig-
nificant source of sediment, with runoff from roads bringing nutrients, sediments,
and heavy metals (Fig. 6-8).
NEW CONSTRUCTION
Figure 6-8.—Activities around the lake shoreline can affect the lake through runoff of fertilirers, pesticides, sedi-
ment, organic -waste, and other contaminants.
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CHAPTER 6: Watershed Management
As the watershed to lake surface area ratio grows, other sources of pollut-
ants become increasingly important:
• Agricultural runoff carrying animal wastes, soil, and nutrients;
• Urban runoff from streets, yards, and rooftops carrying sediment,
organics (oils and greases), nutrients, and heavy metals; and
• Forestry as a source of sediments.
In large watersheds, the contribution from urban, silvicultural, and agricul-
tural areas is generally more significant than that from lakeshore homes.
What Are Best Management
Practices?
So, how can we control these nonpoint sources of pollutants to protect and im-
prove lake quality? If nonpoint sources don't discharge through a pipe, how do we
reduce the amount coming from the watershed?
You have a number of options for improving the water quality of your lake —
from picking up litter around the lake to implementing best management practices
in the watershed. Best management practices have been developed for agricultural,
forestry, urban, mining, construction, and similar land-use activities.
« Agricultural BMPs, for example, have been developed for cropland,
pasture, barnyard and manure management, and fertilizer and pesticide
control.
• Forestry BMPs manage activities such as road construction in
timberlands, timber harvest techniques, forest lands cut or killed by
disease or fire, and the use of pesticides.
• Urban BMPs have been designed to manage stormwater runoff in
developing and established urban areas.
• Construction BMPs prevent erosion and runoff control.
• Abandoned mine BMPs protect lakes from excessive sediment
runoff from tailings and leachate that frequently is very acidic and has
high concentrations of metals. This book does not address abandoned
mine mitigation and mining BMPs.
Best management practices were not initially designed to protect water qual-
ity, but to maintain productivity of farmland and reduce pesticide and fertilizer costs
— or, in cities, to help protect homeowners from mud slides or flooding. Regard-
less of their original intent, many of these watershed best management practices
are useful in lake management and restoration projects.
Managers of lakes and streams focus on best management practices to con-
trol four primary factors:
• Water, runoff, and soil moisture;
• Erosion;
• Nutrient loading; and
• Contaminant loading.
These factors are not independent, but highly interactive. Runoff control, for
example, helps reduce sediments, nutrients, and pesticide runoff and contamination
in lakes and streams. Figure 6-9 shows these factors for a typical construction site.
185
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Managing Lakes and Reservoirs
Figure 6-9.—No-cost or low-cost approaches to reducing erosion (from Wisconsin Dep. Natural Resources, Pub. 4-2300).
1 Plan your construction activities so that
the soil is disturbed a minimal amount
of time. For example, plan to install
gas pipelines, sewer laterals, and
other utilities at close time intervals.
2 Leave grass, frees, and shrubs in place
wherever you can. The more
vegetation, the less sediment-laden
water leaves your site.
3 When you excavate the basement,
pile the soil away from storm sewer
drains — in the back- or side-yard
area, for example. Once you backfill
around the basement, remove any
excess soil from the site.
4 Park cars and trucks on the street, not
on the site. You will keep the soil less
compacted and more water-absorbent,
8
and you will keep mud from being
tracked onto the street.
Arrange to have the street cleaned
regularly while you are building to
remove sediment that preventive
measures failed to keep off the street.
Soon after you start construction,
install a gravel driveway and
encourage cars and trucks to use only
this route on your site. Later, you can
install the permanent driveway over
the gravel.
Build a berm to divert rainwater away
from steep slopes or other highly
erodible areas.
Install straw bales or filter fences along
curbs to filter rainwater before it
reaches the gutter and storm sewer
drains.
9 Seed and mulch, or sod your site as
soon as you complete outside construc-
tion. You will control erosion, and — if
you are building for a prospective
buyer — you will increase the lot's
salability by making it more attractive.
10 If you cannot seed and mulch the
entire lot, cover any critical areas with
a temporary protective material, such
as filter fabric or netting. Later, you
can remove the cover long enough to
install utility lines.
11 Use roof downspout extenders and
sump pump drain tubes to funnel water
away from exposed soils and directly
to the curb and storm sewer. After site
is vegetated, downspout extenders
and drain tubes should outlet to the
vegetated area to maximize
infiltration.
Generally, a best management practice (Table 6-5) involves some combina-
tion of three different approaches:
I. Reducing the generation of pollutants on-site by minimizing rainfall
contact with the pollutant;
2. Restricting water runoff from on-site and up in the watershed to limit
transport or movement of pollutants off the site into nearby waters;
and/or
3. Capturing/trapping pollutants in the watershed and preventing them
from entering the lake or groundwater.
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CHAPTER 6: Watershed Management
Table 6-5.— Best Management Practices.
Best management practices used for various land-use activities. Although the names differ, the
practices are all based on controlling runoff or water movement, erosion, and nutrient and
contaminant loading.
AGRICULTURE
Animal Waste Management
Conservation Tillage
Contour Farming
Contour Stripcropping
Crop Rotation
Fertilizer Management
Integrated Pest
Management
Livestock Exclusion
Range and Pasture
Management
Terraces
URBAN
Flood Storage
Porous Pavement
Street Cleaning
FORESTRY
Ground Cover Management
Pesticide/Herbicide
Management
Riparian Zone Management
Road/Skid Trail
Management
DESCRIPTIVE NOTES
Reduces nutrient and organic matter loading by controlling
timing, amount, and form of manure application to fields.
Any tillage or planting system that maintains at least 30% of
the soil surface covered by residue after planting to reduce
soil erosion by water; examples of conservation tillage
include no-till, ridge-till, or mulch-till.
Conducting field operations, such as plowing, planting,
cultivating, and harvesting, on the contours of the field.
Layout of crops in comparatively narrow strips in which the
farming operations are performed approximately on the
contour. Usually strips of grass or close-growing crops are
alternated with those in cultivated crops or fallow.
Reduces soil erosion and nutrient applications by alternating
with nitrogen-fixing legumes such as alfalfa.
Reduces nutrient loading by controlling timing, amount, and
type of fertilizer to crops.
. Reduces pesticide applications, improves effectiveness of
application, and uses more resistant cultivars.
Excluding livestock from highly erodible land and land near
lakes and streams reduces erosion and nutrient loading.
Reduces runoff and erosion by maintaining vegetative
cover. Reduces manure loadings to streams.
Reduce erosion by shortening flow paths and improving
drainage.
DESCRIPTIVE NOTES
Reduces runoff, sediment, and attached nutrient/contaminant
loading by settling sediment particles out of the water.
Reduces runoff, erosion, and pollutant loading by rainfall
soaking through the pavement into the underlying soil.
Reduces nutrient and contaminant loading by removing
them from the pavement. Pollutants will not be washed into
streams during storms.
DESCRIPTIVE NOTES
Reduces runoff and erosion by maintaining cover over soil
so it is not exposed to raindrops or runoff.
Reduces contaminant loading by controlling the timing,
amount, form, and location of pesticide applications.
Reduces runoff, erosion, and nutrient/contaminant loading
by maintaining vegetation and ground cover along stream
banks (riparian zone]. Buffer strips and streamside
management are other terms used for this BMP.
Reduces length of runoff flow path and reduces erosion.
Erosion from roads and skid trails(i.e., paths where logs are
dragged to the loading area)is the major source of
sediments from forested watersheds.
187
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Managing Lakes and Reservoirs
Table 6-5.— Best Management Practices (eont.).
CONSTRUCTION
Disturbed Area Limits
Nonvegetative Soil
Stabilization
Surface Roughening
MULTICATEGORY
Detention/Sedimentation
Basins
Grassed Waterways
Interception or Diversion
Practices
Maintenance of Natural
Waterways
Riprap
Streamside Management
Zones
Streambank Stabilization
Vegetative Stabilization
Zoning
DESCRIPTIVE NOTES
Reduces erosion by restricting the area of the construction
site that is disturbed or has ground cover removal.
Reduces soil erosion by using matting, mulch, or similar
ground cover over the soil to reduce rainfall eroding the soil
surface.
Reduces the length of runoff flow paths to slow the water,
creating pools or depressions ana reducing the energy ,of
water to dislodge and transport soil off the site.
DESCRIPTIVE NOTES
Reduces the flood peak, sediment, nutrient and contaminant
loading by retaining runoff and letting soil particles and
attached nutrients/contaminants settle out in the basin.
Reduces erosion, nutrient, and contaminant loading by
having runoff flow over a grassy area as it moves toward
the stream. Soil is protected ana grass helps trap nutrients
and contaminants.
Reduces runoff erosion, nutrient, and contaminant transport
by intercepting runoff before the flow path becomes too
long or divesting the runoff away from the lake.
Natural stream banks, riparian zones, and wetlands trap
sediment and nutrients and limit streamside erosion.
A layer of broken rock, cobbles, boulders, aggregate, or
fragments of sufficient size and thickness to resist the erosive
forces of flowing water or wave action; such structures
usually are used to protect channels with relatively high
velocity flow, shores, slopes on dams, or outlets of
structures.
Reduces runoff, erosion, nutrient and contaminant loading
by maintaining vegetative and ground cover next to the
streambank. Typically vegetative strips 30 to 1 00 feet wide.
Reduces erosion and in-stream sediment by protecting and
maintaining the streambank so it does not erode or fall into
the stream.
Reduces runoff, erosion, nutrient, and contaminant loads by
maintaining good vegetative cover at critical locations
throughout the watershed such as highly erodible areas and
streamsides and banks.
Reduces runoff, erosion, nutrient, and contaminant loadings
through legally enforceable regulations for permissible
businesses and land uses and management needed to
protect lakes and streams.
From: Resource Conservation Glossary. 1982. 3rd ed. Soil and Wafer Conservation Society of Amer-
ica. Ankeny, IA. For more detailed lists of BMPS, see U.S. EPA (1993).
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CHAPTER 6: Watershed Management
Runoff and Erosion Control Practices
One of the most powerful forces on earth is rainfall. Even gentle rains can destroy
slopes and create mud slides, gulleys, and flooding — making sediment (plus the
contaminants it carries) the most widespread pollutant in North America. Con-
trolling water and associated runoff from the watershed, then, is the first step in
implementing best management practices.
Erosion is a natural process, so watershed best management practices mimic
the natural processes that control water and soil moisture; thus, they are very
similar across the wide spectrum of land uses (e.g., agriculture, forestry, mining,
construction). Features found in forested watersheds, for example, form the basis
for most efforts to reduce runoff and erosion (Fig. 6-10).
The forest canopy or tree cover intercepts rain as it falls — shrubs and small
trees below the tree tops intercept the rainfall moving through and dripping from
the canopy. A dense cover of pine needles, leaves, and vegetation on the forest floor
further keeps rain drops from hitting bare earth, permitting it to seep into the soil.
And small depressions at all three levels store water to keep it from running off.
When rainfall does begin to run off a forest, it soon encounters a barrier
such as a depression or log that slows it down or a channel that collects and con-
veys it to other channels. Woody debris, rocks, and gravel in these channels slow
the water's flow and thus, reduce soil erosion.
Following rain, the trees and other vegetation take water out of the soil through
their roots. Remaining soil water percolates downward to enter the groundwater
system where it can be discharged into stream channels, thereby reducing the water
in the soil — giving it the capacity to store water from the next rainfall.
These natural features and processes have become the key features of best
management practices to control water and runoff:
• Intercepting or impeding rain drop impacts;
• Creating short flow paths and impeding flow; and
• Designing and protecting channels for collecting the flow.
^ A multi-Story vegetative cover over the site — leaves at several
levels — is more effective in intercepting rainfall than leaves at just one
level. Most best management practices establish or maintain ground cover.
• For example, in agriculture, conservation tillage (keep the crop
residues on the soil; do not plow them under) both covers the soil
and retains moisture.
• Forest timber practices maintain ground cover to protect forest soils
from rainfall.
• Forest loggers may remove haul roads and seed the roadbed following
harvest.
v Creating short f/ow paths and slowing the flow of water
to reduce its velocity (and thus, erosion) is an integral part of almost all
watershed BMPs.
• In agriculture, contour farming, contour stripcropping, conservation
tillage, terraces, and grassed waterways are used to create barriers to
slow runoff.
o,
ne of the most
powerful forces on earth
is rainfall. Even gentle
rains can destroy slopes
and create mud slides,
gulleys/ and flooding —
making sediment (plus
the contaminants it
carries) the most
widespread pollutant in
North America.
189
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§
MANAGEMENT PRACTICES
Water Stops -
Slow flow and
Erosion
Vegetative ~
Buffer _
Retain Sediment, Nutrient
:. Contaminant levels
Best Management Practices (BMPs) work to control
(1) water runoff, (2) erosion, (3) nutrient loading and (4) Contaminant loading.
Sedimentation
Basin
I
Q
Q.
n>
s
3'
Figure 6-10.—Watersheds with good vegetative cover like those in the left-hand side of the figure have lower and slower runoff, less erosion, and lower nutrient
and contaminant loading than watersheds where vegetative cover has been removed. BMPs try to slow runoff, reduce erosion, and trap or retain nutrients and
contaminants and prevent them from entering streams and lakes.
-------
CHAPTER 6: Watershed Management
• In forest management, water stops along forest roads (they look like
little speed bumps), woody debris, and buffer strips near streams
create short flow paths and slow the flow.
• Proper design of logging roads and drainage ditches is important to
forestry management.
• Construction sites roughen the ground surface to create small
depressions and barriers and use hay bales to impede runoff.
• In-stream features mimic the pools that store water in natural stream
channels, and their S-shaped meander that slows the flow and reduces
the size of flood waves.
• Stormwater detention/sedimentation basins, interception/diversion
systems, and similar features are BMPs used in many construction and
urban areas.
v Channels designed to collect and carry runoff are uni-
versal BMPs, regardless of the land use. They include:
• Grassed swales;
• Constructed channels lined with large rocks or riprap;
• Synthetically lined channels that, while expensive, may be better
protection for critical areas; and
• Tree root wads, logs, and natural boulders.
For every land use, most watershed best management practices try
to minimize impacts of rain on the soil.
Nutrient and Contaminant
Control Practices
Eutrophication, like erosion, is a natural process, but people can increase nutrient
loadings to lakes and streams. In general, the major sources of nutrients and con-
taminants come from agricultural and urban land use.
Nutrient and contaminant control practices build on runoff and erosion con-
trol practices. Less runoff means lower erosion and lower transport of both dis-
solved nutrients in the runoff and nutrients sorbed onto soil particles.
But two other principles are vital to controlling nutrients and contaminants:
• Reducing the amount of nutrients and contaminants applied; and,
• Using plant uptake to remove nutrients and contaminants from runoff
and groundwater.
v Don't add more nitrogen and phosphorus than plants
need* This is throwing money away: these nutrients are not used to in-
crease crop production; instead, the excess washes from the watershed
into lakes and streams and damages these ecosystems.
Agriculture uses soil nutrient testing to reduce the nutrients applied to
crops, particularly nitrogen. Phosphorus and pesticides, however, generally
adsorb onto soil particles so reducing soil erosion also helps control them.
191
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Managing Lakes and Reservoirs
jL_oning and
ordinances go hand in
hand with other BMPs in
managing watershed
activities.
T Install vegetative buffer strips next to streams and lakes to
help prevent nutrients and contaminants from entering the water body by
trapping those carried by eroded soil particles.
• Streamside vegetation uses nutrients from the water for growth.
T Use plants to remove certain types of heavy metals or organic
contaminants.
• In a process known as phytoremediation, plants are being used to
clean up certain types of heavily contaminated soils by absorbing the
contaminants from the soil.
Reducing nutrient concentrations in surface runoff, however, can increase
their concentrations in subsurface or groundwater. If nutrients such as nitrate,
which are readily soluble in water (but do not adsorb to soils), are excessively ap-
plied to soils and not permitted to run off, they will seep into the soils and con-
tinue moving down until they encounter a barrier such as clay or enter the
groundwater.
• Too much animal manure, liquid fertilizers containing nitrogen, and
ammonium nitrate can significantly contaminate groundwater, partic-
ularly in watersheds with permeable soils or bedrock such as limestone.
Rain leaches nutrients out of soils as it seeps into them and can cause
high nitrate concentrations in groundwater and in domestic wells.
Herbicides such as atrazine have been found in the spring in relatively high
concentrations in lakes, streams, and groundwater throughout the Midwest, illus-
trating the problems caused by excessive applications over large areas.
Although simply following manufacturers' directions for application can help
prevent contamination of lakes and streams and groundwater, several programs
can be useful:
• Manure management programs can help farmers contain the manure
and apply it when needed by crops, eliminating excess.
• Well-head protection programs have been developed to help reduce
soluble nutrient and herbicide concentrations in watershed areas that
contribute to groundwater recharge.
• Integrated pest management programs for both agriculture and
forestry reduce the use of pesticides by integrating weed- and
insect-resistant crop varieties, crop rotation, stripcropping, and
biological agents with pesticides to control pests.
Zoning and Ordinances
Zoning requirements and ordinances that regulate various types of land uses and
development can be effective, long-term approaches in the watershed manage-
ment tool box. Example ordinances protecting stream buffer zones, open space
development, greenways, stormwater drainage, and other activities can be found
on the EPA website at www.epa.gov/owow/nps.ordinance and the Center for
Watershed Protection website at www.cwp.org.
Zoning and ordinances go hand in hand with other BMPs in managing water-
shed activities.
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Water Conservation Practices
With a lake nearby, conserving water might not seem critical. But reducing water
usage also reduces wastewater discharges.
• Water-saving devices such as flow-reducing showerheads and
water-saving toilets (or just using less water in the tank) can cut
household wastewater flows by as much as 25 percent (U.S. EPA,
1981).
Most of these procedures are very simple, even obvious (see Table 6-6), but
if many of you living around the lake follow them, the water you conserve may al-
low your community to use a smaller wastewater treatment facility — at the very
least, using less water can lower day-to-day operating costs for treatment chemi-
cals and utilities.
And look at these other options:
• If your treatment capacity is nearly maxed out, conserving water may
be the best step you can take.
• If you're connected to a regional sewer system, conservation can
reduce treatment charges, which are usually based on the volume of
sewage treated — based on your water meter readings and prorated
by household.
Water conservation, then, not only costs less in the long run but also pro-
tects your lake from excessive organic matter and nutrients, as your wastewater
discharges decline. More careful usage may also lower nonpoint sources from ac-
tivities such as watering lawns. So as you prepare your management plan, remem-
ber to include water conservation as an essential best management practice. The
EPA website, www.epa/gov/owm, also has ideas and information on water effi-
ciency and recycling and reuse.
Integrated Watershed — and Lake —
Management
Watershed and lake management starts with a plan — what are the lake prob-
lems, where are they occurring, why are they occurring, what do you want to
achieve, how can you go about it?
As you have found in this chapter, many management practices can be used
to reduce these problems and help achieve lake and watershed management ob-
jectives.
But there is no magic bullet: rather, it is the combination of multiple practices
that best control point and nonpoint sources of pollution in the watershed and in
your lake. Many approaches can be used and many local, state, and federal agen-
cies, universities, and organizations can provide technical and financial assistance
and/or cost-sharing for watershed management. Use them! It is the integration of
these watershed management practices and the implementation of a watershed
plan that build the foundation for effective lake management.
1
\Jo as you prepare
your management plan,
remember to include
water conservation as
an essential best
management practice.
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Table 6-6.— Conscientious use of water can prevent excess runoff and reduce
the volume of wastewater treated, both of which help protect lake water quality.
WATER CONSERVATION TECHNIQUES
Inspect the plumbing system for leaks.
Install flow-control devices in showers.
Turn off all water during vacations or long periods of absence.
Check the frequency with which home water softening equipment regenerates and
backaches. It can use as much as 100 gallons of water each time it does this.
Insulate hot water pipes to avoid having to clear the "hot" line of cold water during use.
Check all faucets, inside and out, for drips. Make repairs promptly. These problems get
worse—never better.
Reduce the volume of water in the toilet flush tanks with a quart plastic bottle filled with
water (bricks lose particles, which can damage the valve).
Never use the toilet as a trash basket for facial tissue, etc. Each flush uses 5 to /gallons
of water. Items carelessly thrown in could clog the sewage disposal system.
Accumulate a full laundry load before washing, or use a lower water level setting.
Take showers instead of baths.
Turn off shower water while soaping body, lathering hair, and massaging scalp.
Bottle and refrigerate water to avoid running excess water from the lines to get cold
water for meals. Shake bottle before serving to incorporate air in the water so it doesn't
taste flat.
• To get warm water, turn hot water on first; then add cold water as needed. This is
quicker this way and saves water too.
Wash only full loads of dishes. A dishwasher uses about 9 to 13 gallons of water per
cycle.
When washing dishes by hand, use one pan of soapy water for washing and a second
pan of hot water for rinsing. Rinsing in a pan requires less water than rinsing under a
running faucet.
Use rinse water—"gray water"—saved from bathing or clothes washing to water indoor
plants. Do not use soapy water on indoor plants. It could damage them.
• Vegetables requiring more water should be grouped together in the garden to make
maximum use of water applications.
• Mulch shrubs and other plants to retain moisture in the soil longer. Spread leaves, lawn
clippings, chopped bark or cobs, or plastic around the plants. Mulching also controls
weeds that compete with garden plants for water. Mulches should permit water to soak
into the soil.
Try "trickle" or "drip" irrigation systems in outdoor gardens. These methods use 25 to 50
percent less water than hose or sprinkler methods. The tube for the trickle system has
many tiny holes to water closely spaced plants. The drip system tubing contains holes or
openings at strategic places for tomatoes and other plants that are more widely spaced.
• Less frequent but heavier lawn watering encourages a deeper root system to withstand
dry weather better.
Plan landscaping and gardening to minimize watering requirements.
When building or remodeling, consider:
—Installing smaller than standard bath tubs to save water.
—Locating the water heater near where hottest water is needed—usually in the
kitchen/laundry area.
Source: from a bulletin issued by the Arkansas Cooperative Extension Service (USDA, 1984).
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CHAPTER 6: Watershed Management
References
Arkansas Cooperative Extension Service. 1984. Bulletin on Water Conservation
Techniques. U.S. Dep. Agriculture, Washington, DC.
Colorado Department of Public Health and Environment. 1997. The Total Maximum
Daily Load Process. Water Quality Control Div., Denver.
Federal Interagency Stream Restoration Working Group. 1998. Stream Corridor
Restoration: Principles, Processes, and Practices. Internet at
www. us da.gov/stream_resto rati o n.
Intergovernmental Advisory Committee. 1995. Ecosystem Analysis at the Watershed
Scale: Federal Guide for Watershed Analysis-Version 2.2. Portland, OR.
Minnesota Department of Natural Resources. 1999. Landscaping for Wildlife and
Water Quality. St. Paul.
Montgomery, D. G. Grant, and K. Sullivan. 1995. Watershed analysis as a framework
for implementing ecosystem management. Water Retour. Bull. 31 (3):369-86.
Ohio Environmental Protection Agency. 1997. A Guide to Developing Local
Watershed Action Plans in Ohio. Columbus.
Soil and Water Conservation Society of America. 1982. Resource Conservation
Glossary. 3rd ed. Ankeny, 1A.
U.S. Environmental Protection Agency. 1993. Guidance Specifying Management
Measures for Sources of Nonpoint Pollution in Coastal Waters.
EPA-840-B-93-001 c. www.epa.gov/owow/nps/MMGI/. Off. Wetlands Oceans and
Watersheds, Assess. Watershed Prot. Div., Washington, DC.
. 1997. Technical Guidance Manual for Developing Total Maximum Daily
Loads: Book 2. Streams and Rivers—Part 1: Biochemical Oxygen Demand /
Dissolved Oxygen and Nutrients/Eutrophication.EPA 823-B-97-002. Off. Sci.
Tech., Stand. Appl. Sci. Div., Washington, DC.
-. 1998. Clean Water Action Plan: Restoring and Protecting America's Waters.
USDA Natural Resource Conserv. Serv. and U.S. Environ. Prot. Agency.
ERA-840-R-98-001. National Center for Environmental Publications and
Information (800/490-9198).
U.S. Geological Survey. 1997. Poster Series. Water Quality. Grade school ed. USGS
Branch Information Services, Denver, CO.
See Appendix 6-A for additional Guidance Manuals, Web sites, and Links.
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196
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APPENDIX 6-A: Best Nonpoiht Source Resources
APPENDIX 6-A
Best Nonpoint Source
Resources
LJ GENERAL NOTES:
* means the organization is likely to charge for the listed document
NSCEP means the document is free from the National Service Center for
Environmental Publications and Information at (800) 490-9198 or (513) 489-8190.
AGRICULTURAL BMP MANUALS
Animal Facilities
CQ Animal Waste Management Field Handbook: USDA NRCS National
Engineering Handbook (NEH): Part 651. U.S. Department of Agriculture, Natural
Resources Conservation Service. The Animal Waste Management Field Handbook is
an excellent resource for animal waste system designers or anyone interested in
how animal waste is typically handled and stored. The document covers all aspects
of the design and management of animal facilities and has lots of very useful
diagrams and figures. See: http://www.ftw.nrcs.usda.gov/awmfh.html.
03 Earthen and Manure Storage Design Considerations. Natural Resource,
Agriculture, and Engineering Service, Cooperative Extension (1999). Publication
number NRAES-109 covers environmental policy as well as manure storage and
management. The text can be technical but also covers the basics of environmental
issues and risk reduction. NRAES, Cooperative Extension, 152 Riley-Robb Hall,
Ithaca, NY 14853-5701, (607) 255-7654. See: http://www.nraes.org/.
03 Liquid Manure Application Systems Design Manual. Natural Resource,
Agriculture, and Engineering Service, Cooperative Extension (1998). Document
number NRAES-89 focuses on the characteristics and land application of liquid
manure. Evaluations of application sites for environmental risk, manure handling, and
safety are key issues. NRAES, Cooperative Extension, 152 Riley-Robb Hall, Ithaca, NY
14853-5701, (607) 255-7654. See: http://www.nraes.org/.
B3 On-form Composting Handbook. Natural Resource, Agriculture, and
Engineering Service, Cooperative Extension (1992). NRAES-54 describes the
composting process in detail as well as discusses the benefits and drawbacks of using
composting in an operation. Raw materials, various composting methods, how to use
compost, and how to market compost are all covered in this 186-page manual. For
copies, contact NRAES, Cooperative Extension, 152 Riley-Robb Hall, Ithaca, NY
14853-5701, (607) 255-7654. See: http://www.nraes.org/.
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AGRICULTURAL BMP MANUALS: Cross-cutting; multi-issue manuals
E3 Poultry Waste Management Handbook. Natural Resource, Agriculture, and
Engineering Service, Cooperative Extension (1999). NRAES-132) The handbook
discusses storage, treatment, and utilization of poultry litter and mortalities.
Emphasis is placed on composting and nutrient management. For copies, contact
NRAES,Cooperative Extension, 152 Riley-Robb Hall, Ithaca, NY 14853-5701, (607)
255-7654. See: http://www.nraes.org/.
E3 Poultry Water Quality Handbook: 2nd ed. expanded. Poultry Water Quality
Consortium (1998). This handbook includes a series of fact sheets that create a
comprehensive poultry management binder. The handbook covers water and air
quality, waste and mortality management, and alternative technologies for poultry
and egg producers. Contact the Poultry Water Quality Consortium for a copy: 6100
Building, Suite 4300,5720 Uptain Road, Chattanooga, TN 3741 I, or call (423)
855-6470.
Cross-cutting; multi-issue manuals
EQ Core4 Conservation Practices: the common sense approach to natural
resource conservation. U.S. Department of Agriculture, Natural Resources
Conservation Service (1999). This reference manual is intended to help USDA
NRCS personnel and other conservation and nonpoint source management
professionals implement effective programs on the land using four core conservation
practices: conservation tillage, nutrient management, pest management, and
conservation buffers. The Core4 concept was established by the Conservation
Technology Information System and is supported by USDA, EPA, and agribusiness.
For more information or to receive a copy on CD-ROM contact Arnold King,
Grazing Lands Technology Institute, NRCS, P.O. Box 6567, Fort Worth, TX 76115.
The document can also be accessed at: http://www.ftw.nrcs.usda.gov/tech_ref.html.
Q3 Farming for Clean Water in South Carolina: a handbook of conservation
practices. South Carolina Department of Natural Resources (1997). Compiled by
Dennis DeFrancesco of USDA NRCS for the South Carolina DNR, this 135-page
manual covers all the farming basics: calibration, stripcropping, water diversions,
composting, IPM, recordkeeping, pesticides, nutrients ... and the list goes on. Based in
large part on the Field Office Technical Guide and Clemson University publications,
this document was produced using Section 319 funding. While not in-depth, the
document has great pictures and an easy to follow, consistent format. Contact
SCDNR for more information: (803) 737-0800, ext. 168.
03 Guidance Specifying Management Measures for Sources of Nonpoint
Pollution in Coastal Waters. U.S. Environmental Protection Agency, Office of
Water (1993). Developed for use by State Coastal Nonpoint Pollution Control
Programs, Chapter 2 of this document covers erosion control, animal feeding
operation management, grazing practices, and management of nutrients, pesticides,
and irrigation water. This document has become a must-have for nonpoint source
control professionals. Find it on the Internet at
http://www.epa.gov/owow/nps/MMGI/Chapter2/index.html.
03 National Handbook of Conservation Practices. U.S. Department of
Agriculture, Natural Resources Conservation Service. This resource contains all
conservation practice standards issued by the Natural Resources Conservation
Service. All conservation topics are covered: nutrient management, conservation
tillage, erosion control, irrigation, grazing, etc. This handbook is available on-line at
http://www.ftw.nrcs.usda.gov/nhcp_2.html.
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AGRICULTURAL BMP MANUALS: Cross-cutting; multi-issue manuals
03 Soybean Management and the Land: A Best Management Practices
Handbook for Growers. American Soybean Association (2000). This manual is a
two-for-one bonus. The "Resource Book" presents information on BMPs for the
farmstead, cropland, pastureland, and other areas. All types of BMPs are covered:
erosion, pest management, nutrients, well protection, buffers, etc. The BMP
discussion includes real world examples of how these practices work through
testimonials from real farmers. The "Workbook" allows soybean growers to assess
the conditions on their farms and determine their environmental risk level. The
"Workbook" also helps the producer make a plan for improvement. Contact the
American Soybean Association, (800) 688-7692, ext.210; ASA, 12125 Woodcrest
Executive Drive, Suite 100, St. Louis, MO 63141, bmphandbook@soy.org (cost $36).
ffl 50 Ways Farmers Can Protect Their Groundwater. University of Illinois,
College of Agriculture, Cooperative Extension Service (1993). The title says it all.
While focusing on the management of fertilizers and pesticides, this 190-page book
briefly covers livestock waste, wells, hazardous chemicals, and water testing. Contact
Information Services, (217) 333-2007, for a copy or look at it on-line at
http://web.aces.uiuc.edu/watershed/training edu.
03 60 Ways Farmers Can Protect Surface Water. University of Illinois, College of
Agriculture, Cooperative Extension Service (1993).Topics include residue
management, water flow control, nutrient management, livestock waste handling, and
pesticide management. Contact Information Services, (217) 333-2007, or find it
on-line at http://web.aces.uiuc.edu/watershed/training.edu.
Erosion
03 (See list for Cross-cutting Manuals)
Grazing
03 Best Management Practices for Grazing. Montana Department of Natural
Resources and Conservation (1999).This manual describes the BMPs developed as
part of Montana's Prescribed Grazing Standard NRCS Conservation Practice
Standard. The manual covers grazing management plans, riparian areas, forestlands,
and winter feeding areas. For copies, contact the Conservation Districts Bureau,
Department of Natural Resources and Conservation, P.O. Box 201601, Helena, MT
59620-1601, or call (406) 444-6667.
03 Managing Change: livestock grazing on western riparian areas. U.S.
Environmental Protection Agency Region 8 (1993). Written for "the men and
women who move the livestock," this 31 -page booklet encourages ranchers to look
at the water quality and habitat impacts of their grazing practices. Excellent
photographs illustrate how streambanks and water quality are degraded by
improper grazing and how improved management can restore the health of the
streams. Quick-fix structural components for stream training are cautioned against
as an inadequate substitute for long-term responsible herd management. U.S.
Environmental Protection Agency Region 8,999 18th Street, Suite 500, Denver CO
80202-2466, and Northwest Resource Information Center, Inc., P.O. Box 427, Eagle,
ID 83616.
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AGRICULTURAL BMP MANUALS: Grazing
03 National Range and Pasture Handbook. U.S. Department of Agriculture,
Natural Resources Conservation Service, Grazing Lands Technology Institute (1997).
Part of the NRCS Field Office Technical Guide, this manual covers inventorying,
monitoring, and managing grazing lands as well as livestock nutrition, behavior, and
husbandry. Special sections deal with the economics of grazing, wildlife management,
and hydrology. See: http://www.ftw.nrcs.usda.govtech_ref.html.
Irrigation
03 Irrigation Guide: USDA NRCS National Engineering Handbook: Part 652.
U.S. Department of Agriculture, Natural Resources Conservation Service (1997).
This manual describes NRCS-recommended processes for planning, designing,
evaluating, and managing irrigation systems. GSA National Forms and Publications
Center, 7CAF, 501 W. Felix Street, Warehouse 4 Dock I, Fort Worth, TX 76115.
03 Irrigation Management Practices to Protect Ground Water and Surface
Water Quality State of Washington. Washington State Department of Ecology
and Washington State University Cooperative Extension (1995). The handbook
emphasizes a systems approach to irrigation management and water quality
protection. Introductory material covers water quality issues and the basics of
soil-water-plant relationships and irrigation processes. Contact State of Washington,
Department of Ecology, P.O. Box 47600, Olympia, WA 98504-7600.
Nutrient Management
03 (See list for Cross-cutting Manuals)
03 Agricultural Phosphorus and Eutrophication. U.S. Department of Agriculture,
Agricultural Research Service, ARS-149 (1999). A small booklet co-authored by
USDA ARS and U.S. Environmental Protection Agency staff, this resource details the
relationship between phosphorus application to agricultural fields and
eutrophication of our nation' s waterways. A good primer on the phosphorus cycle
and actions that can help control phosphorus. For copies contact USDA ARS,
Pasture Systems & Watershed Management Research Laboratory, Curtin Road,
University Park, PA 16802-3702 (while supplies last) or purchase copies from the
National Technical Information Service (703) 605-6000.
Pesticides
03 Best Management Practices for Agrichemical Handling and Farm
Equipment Maintenance. Florida Department of Agriculture and Consumer
Services and Florida Department of Environmental Protection (May 1998). This
42-page booklet covers pesticides, fertilizers, solvents, and degreasers. Emphasis is
placed on storage, mixing, loading, spill management, and disposal. Emergency
reporting is also stressed. See: http://www.dep.state.fl.us/water/slerp/
nonpoint_stormwater/documents/ pubinfo.htm#agriculturalpollutionprevention.
03 National Integrated Pest Management Network. U.S. Department of
Agriculture, Cooperative State Research, Education, and Extension Service (2000).
The National Integrated Pest Management Network (NIPMN) is the result of a
federal-state extension partnership dedicated to making the latest and most accurate
pest management information available on the World Wide Web. Participating
institutions have agreed to a set of standards which ensure science-based, unbiased
pest management information. See: http://ipmworld.umn.edu.
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APPENDIX 6-A: Best Nonpoint Source Resources
FORESTRY BMP MANUALS
BMP Implementation and Effectiveness
03 Evaluating the Effectiveness of Forestry BMPs in Meeting Water Quality
Goals or Standards. U.S. Department of Agriculture, Forest Service (Publication
1520) (July 1994). The purpose of this document is to help forest managers and
their staff develop water quality monitoring plans to evaluate the effectiveness of
forestry BMPs in meeting water quality goals or standards. It deals with the design of
monitoring projects and the selection of variables and methods for monitoring them.
Contact: U.S. Department of Agriculture, Forest Service, Southern Region, 1720
Peachtree Road NW.Atlanta, GA 30367.
B3 Techniques for Tracking, Evaluating, and Reporting the Implementation of
Nonpoint Source Control Measures for Forestry. U.S. Environmental Protection
Agency (July 1997). This guidance is intended to assist state, regional, and local
environmental professionals in tracking the implementation of BMPs used to control
nonpoint source pollution generated by forestry practices. Information is provided
on methods for sample site selection, sample size estimation, sampling, and result
evaluation and presentation. The focus of the guidance is on the statistical
approaches needed to properly collect and analyze data that are accurate and
defensible. See: http://www.epa.gov/owow/nps/forestry/index.html.
CQ Wisconsin's Forestry BMPs for Water Quality: The 1997 BMP Monitoring
Report, Wisconsin Department of Natural Resources, Bureau of Forestry
(PUB-FR-145-99). This document describes the monitoring results from forestry
BMP monitoring on timber sales. The monitoring was done to determine the extent
to which BMPs were being applied throughout the state, the effectiveness of
properly applied BMPs in protecting water quality, and the effects of not applying
BMPs where needed. In addition to the findings, the report discusses the general
framework and methods used to design the audit, as well as conclusions and
recommendations. Phone requests for publication: (608) 267-7494.
BMP Manuals
£Q Georgia's Best Management Practices for Forestry. Georgia Forestry
Commission (January 1999). The purpose of this manual is to inform landowners,
foresters, timber buyers, loggers, site preparation and reforestation contractors, and
others involved with silvicultural operations about common sense, economical, and
effective practices to minimize soil erosion, stream sedimentation, and thermal
pollution. See: http://www..forestry.uga.edu/efr/docs/bmp-contents.html.
G3 Montana BMPs for Forestry. Montana Department of State Lands, Missoula.
Montana's water quality protection program for forestry involves a combination of
regulatory and non-regulatory approaches. Since the i 970s, these non-regulatory
Forestry Best Management Practices have provided guidance as minimum water
quality protection standards for forestry operations. Phone requests for publication:
(406) 542-4200. See: http://www.dnrc.state.mt.us/forestry/sfburea.htm.
CQ Montana Guide to the Streamside Management Zone Law and Rules.
Montana Department of State Lands, Missoula. This booklet explains and illustrates
the SMZ law and rules as they apply to forest practices. Phone requests for
publication: (406) 542-4200. See: http://www.dnrc.state.mt.us/forestry/sfburea.htm.
03 Sustaining Minnesota Forest Resources: Voluntary Site-level Forest
Management Guidelines for Landowners, Loggers, and Resource Managers.
Minnesota Forest Resources Council (February 1999). This guidebook was
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FORESTRY BMP MANUALS: BMP Manuals
developed as a collaborative statewide effort involving diverse forestry and water
quality stakeholders. It provides a set of integrated guidelines that serve as a menu
of options which address impacts on forest and water resources. See:
http://www.frc.state.mn.us.
CD Wisconsin's Forestry BMPs for Water Quality: A Field Manual for Loggers,
Landowners, and Land Managers. Wisconsin Department of Natural Resources,
Bureau of Forestry (1997). This field manual lists over 119 BMPs for forestry
activities including road building, timber harvesting, prescribed burning, and the
application of chemicals. To request a publication call: (608) 267-7494.
Managing Private Non-industrial Forests
03 Forest*A*Syst:A Self-assessment Guide for Managing Your Forest. The
objective of this publication is to encourage owners of forests — large or small —
to manage that forest for recreation, wildlife, and timber, while protecting water
quality resources. It is a national model, intended for states to tailor to their own
needs and purposes. See: www.forestasyst.net.
Regulations
03 Regulation of Private Forestry Practices by State Governments. Minnesota
Agricultural Experiment Station (Bulletin 605-1995)( 1995). A comprehensive
overview of state forestry programs, with background information on history and
evolution of the legal system relating to forestry practices. The document also
describes current program effectiveness and constraints, as well as emerging policy
and management issues. Contact: Minnesota Agricultural Experiment Station, 1420
Eckles Avenue, St. Paul, MN 55108.
G3 Water Quality and BMPs for Loggers. An Internet resource providing detailed
state-by-state information on BMPs, public agencies, laws, ordinances, maps, related
links, and training and education opportunities. See: hffn://www.forestry.uga.edu/bmp.
Riparian, Wetland and Bottomland Forests
E3 Chesapeake Bay Riparian Handbook: A Guide for Establishing and
Maintaining Riparian Forest Buffers. U.S. Department of Agriculture, Forest
Service, Northeastern Area (NA-TP-02-97) (1997). The purpose of this handbook is
to provide professional land managers and planners with the latest information on
the functions, design, establishment, and management of riparian forest buffers. See:
www.chesapeakebay.net/pubs/subcommittee/nsc/forest/handbook
Roads
03 Fish Passage Through Culverts. U.S. Department of Transportation, Federal
Highway Administration (FHWA-FL-90-006), and U.S. Forest Service, San Dimas
Technology and Development Center (November 1990). This report is intended to
review, summarize, and update current information on fish passage through culverts. It is
geared primarily toward fish biologists, hydrologists, and engineers who will be designing
projects that pass fish. Phone requests for publication: (909) 599-1267, ext. 246.
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APPENDIX 6-A: Best Nonpoint Source Resources
FORESTRY BMP MANUALS: Roads
03 Handbook for Forest and Ranch Roads. Mendocino County Resource
Conservation District (June 1994). This document is a guide and field manual for
anyone involved with roads in the forest or on the ranch. Contains many helpful
photographs and illustrations, charts and tips on approaching road building from the
planning through construction, maintenance, and closure stages. Phone requests for
publication: (707) 468-9223.
B3 Managing Roads for Wet Meadow Recovery. U.S. Department of Agriculture,
Forest Service, Southwestern Region (FHWA-FLP-96-016) (1996). The purpose of
this handbook is to provide a reference document for use in understanding wet
meadow functions, identifying treatment opportunities, planning and implementing
new or remedial treatments, and monitoring results. Available through the National
Technical Information Service: (703) 605-6000 or www.ntis.gov.
03 Riparian Road Guide:Managing Roads to Enhance Riparian Areas.*
Terrene Institute in cooperation with U.S. Environmental Protection Agency (1994).
This guide was written primarily for local government personnel, elected officials, and
road designers and contractors in the arid and semiarid southwestern United States.
The general principles, however, are applicable in other regions of the country if
techniques are modified accordingly. It reviews the impacts of roads on water quality,
describes common conflicts, and suggests ways to correct and avoid problems
associated with road building in riparian areas. Phone requests for publication: (800)
726-4853.
ffl Road Closure and Obliteration in the Forest Service. U.S. Department of
Agriculture, Forest Service, San Dimas Technology and Development Center
(Document 7700) (June 1996). This guide is a compilation of information on road
closure and obliteration and related watershed restoration work as an aid to
resource specialists, engineers, and interdisciplinary teams. Phone requests for
publication: (909) 599-1267, ext. 246.
£Q Temporary Stream and Wetland Crossing Options for Forest Management.
U.S. Department of Agriculture, Forest Service (Report NC-202) (November 1998).
The purpose of this document is to fill the information gap relating to options that
forest managers are able to pursue when addressing water quality concerns from
stream and wetland crossings. It provides detailed information about a broad range
of reusable temporary crossing options and identifies research and education needs.
Contact: U.S. Department of Agriculture, Forest Service, North Central Research
Station, 1992 Folwell Avenue, St. Paul, MN 55108.
03 Water/Road Interaction Technology Series. U.S. Department of Agriculture,
Forest Service, San Dimas Technology and Development Program (September 1997).
This series is part of an ongoing effort to identify information and methods on
hydrological aspects of developing, operating, and managing forest roads by
communicating state-of-the-art information, identifying knowledge gaps, and
providing a framework for addressing future research and development needs on
this subject. Phone requests for publication: (909) 599-1267, ext. 246.
Annotated Bibliography
ffl Water Quality Effects and Nonpoint Source Control for Forestry: An
Annotated Bibliography. EPA-84I/B-93-005 (August 1993). Covers in-stream
studies, roads, timber harvest, streamside management areas, wetlands, water quality
monitoring, and modeling. Available through the National Service Center for
Environmental Publications (NSCEP): (800) 490-9198.
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MARINA BMP DOCUMENTS
Programs/Manuals
£3 Clean Marina+Clean Boating+Clean Water Partnership: A Resource
Manual for Pollution Prevention in Marinas. Puget Soundkeeper Alliance, Puget
Sound Water Quality Authority (January 1995). This manual provides a resource
workbook for marina owners and operators. It contains boater tips on when and
where to use best management practices to prevent and reduce NPS pollutants
from entry into waters of Puget Sound. Federal and Washington State environmental
laws (including CZARA and marina management measures) and penalties for
noncompliance are explained. A partnership approach between marinas and boaters
is encouraged as the way to control pollution and to protect the environment and
beauty of Puget Sound. The BMPs discussed include waste oil and spills, fuel dock
operation and maintenance, bilge water discharge, pumpout facilities, boat cleaning
and, solid and hazardous waste disposal. For copies contact: Puget Soundkeeper
Alliance, or call (260) 286-1309.
03 Clean Marinas — Clear Value: Environmental and Business Success Stories.
U.S. Environmental Protection Agency (EPA-841-R-96-003) (August 1996). This
document features 25 marina case studies focusing on the economic benefits
realized by marina managers who have incorporated management measures at their
marinas. The return on their investment in developing a clean marina exceeded
expectations both in profits and increased business. This report intends to show
that managing polluted runoff through environmental enhancements is good for
business, good for boating, and good for the environment. The document includes
tables on cost/benefit, general benefits from environmental changes, and
management measures employed at each of the marinas studied. For copies contact:
U.S. Environmental Protection Agency, Nonpoint Source Control Branch, 1200
Pennsylvania Avenue N.W., (4503-F) Washington, D.C. 20460; or call (202) 260-7009.
03 Clean Marina Practices Handbook, The Ontario Marina Operators Associa-
tion, Ontario, Canada (1997). This handbook is intended as an educational tool for
owners and operators of marinas and yacht clubs on pollution prevention and reduc-
tion practices. The handbook presents a detailed discussion of measures to control
water, air, and land pollution from recreational boating activities. Included in the manual
are descriptions of pollutants found at marinas, pumpout needs, and stormwater
management; excerpts of applicable legislation; and recommendations to promote clean
marinas through public awareness and voluntary compliance with pollution prevention
practices. For copies contact The Ontario Marina Operators Association, 4 Cataraqui
Street, Suite 211, Kingston, Ontario K7KIZ7; or call (613) 547-6662.
09 Clean Vessel Act of 1992 Pumpout Grant Program: American Success
Stories. U.S. Fish & Wildlife Service, Division of Federal Aid (1997). Case studies
from USFWS regions and states illustrating how the program has worked in its first
five years. For a copy, write to U.S. Fish & Wildlife Service, Division of Federal Aid,
4401 North Fairfax Drive, Arlington, VA 22203; www.fws.gov.
03 Design Handbook for Recreational Boating and Fishing Facilities. States
Organization for Boating Access, Washington, DC (April 1996). A practical handbook
describing the techniques and best practices for shoreline protection, boat ramp
design, location of restroom facilities, and operations and maintenance of waterside
components. For copies contact: SOBA, P.O. Box 25655, Washington, DC 20007.
03 National Management Measures Guidance to Control NPS Pollution from
Marinas and Recreational Boating. U.S. Environmental Protection Agency (EPA
841 -D-01 -001). The latest in EPA series of "management measures guidance"; e.g.,
Coastal guidance. Contact NSCEP: (800) 490-9198.
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APPENDIX 6-A: Best Nonpoint Source Resources
MARINA BMP DOCUMENTS: State Manuals
State Manuals
03 Best Management Practices for Coastal Marinas. Connecticut Department
of Environmental Protection (August 1992). This report overviews potential impacts
from marina facilities, identifies common pollutants targeted for control, and
describes operational BMPs for addressing potential impacts. The report includes
selected state policies and mechanisms for implementing management practices. Six
existing state marinas were surveyed to review a variety of harbor settings and
functions to determine impacts attributable to pollutants found at these marinas.
The document is generally based on the CZARA management measures guidance
with similar marina and recreational boating BMPs. For copies contact: Connecticut
DEP, 79 Elm Street, Hartford, CT 06106-5127.
03 Best Management Practices for Marinas and Boatyards: Controlling
Nonpoint Pollution in Maine. Maine Department of Environmental Protection
(December 1995). This practical manual discusses common pollutants and their
potential impacts in marina waters. Lists BMPS as guidance to manage runoff from
stormwater, solid waste, fuel and hydrocarbons, hazardous materials, liquid waste,
and sewage discharge from boats at both recreational and commercial marinas and
boatyards. The manual includes CZARA and CWA requirements and descriptive
material from EPA's management measures guidance, but stresses that it is not a
regulatory document. Included in the manual are useful fact sheets, a model oil spill
response plan, and an operations and maintenance plan based on the Rhode Island
model. For copies contact: Maine DEP, Augusta, ME 04333; or call (207) 287-7688.
B3 Environmental Guide for Marinas: Controlling Nonpoint Source and Storm
Water Pollution in Rhode Island. Rhode Island Sea Grant, University of Rhode
Island (September 1996). This environmental guide provides information on
pollutants and potential impacts at marinas, state operations and maintenance plan
requirements, oil spill response plans, and BMP worksheets that marina operators
can use to develop the required O&M Plan for controlling polluted runoff at
marinas. The guide is designed to meet the state's Coastal Nonpoint Source Control
Plan requirements for marinas and recreational boating under CZARA. For copies
contact: Rhode Island Sea Grant, Communications Office, University of Rhode Island,
Narragansett, RI 02882-1197
03 Marina Pollution Prevention Manual. University of California Sea Grant
Extension Program (1995). A useful manual in fact sheet format outlining BMPs for
voluntary compliance by marina operators and boaters and calling attention to
potential problems caused by improper operation and maintenance. Topics cover
boat cleaning, engine and hull maintenance, oil and hazardous waste disposal, fuel
handling, and marina staff training. For copies contact: California Sea Grant Program,
University of California, La Jolla, CA 92093-0232; or call (858) 534-4440.
03 Maryland Clean Marina Guidebook. Maryland Department of Natural
Resources (1998). This Guidebook was developed in response to the CZARA
program and the state's need to strengthen its nonpoint source pollution controls at
marinas and recreational boating facilities. The material presented covers key
CZARA management measures with supporting BMPs organized under
environmental concerns, legal setting, applicable BMPs, and information sources. Also
presented are state and federal laws and regulations as enforceable policies and
mechanisms affecting marinas. For copies contact: Maryland DNR, Waterway
Resources Division, Annapolis, MD 21401;or call (410) 260-8770.
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Managing Lakes and Reservoirs
NONPOINT SOURCE MONITORING
£9 /Monitoring Guidance for Determining the Effectiveness of Nonpoint
Source Controls. U.S. Environmental Protection Agency, Office of Water (EPA
841-B-96-004) (1997). The manual gives an overview of nonpoint source pollution
and covers the development of a monitoring plan, data analysis, quality
assurance/quality control, and biological monitoring. Contact the National Service
Center for Environmental Publications at (800) 490-9198.
03 National Handbook of Water Quality Monitoring. Part 600, National
Water Quality Handbook (1996). Covers statistical design, variable selection,
sampling location, sample analysis, and much more. Contact U.S. Department of
Agriculture, Natural Resources Conservation Service for a copy. See:
http://www.wcc.nrcs.usda.gov/water/quality/frame/wqam/Guidance_Documents/guid
ance_documents.
£Q Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers:
periphyton benthic macroinvertebrates and fish. 2nd ed. U.S. Environmental
Protection Agency (1999). This document describes refined and revised methods for
conducting cost-effective biological assessments of streams and small rivers. It
focuses on periphyton, benthic macroinvertebrates, and fish assemblages, and on
assessing the quality of the physical habitat. See:
http://www.epa.gov/owow/monitoring/rbp/.
EQ Techniques for Tracking, Evaluating, and Reporting the Implementation of
Nonpoint Source Control Measures — Agriculture. U.S. Environmental
Protection Agency (EPA 841-B-97-010) (1997). Focusing specifically on monitoring
agricultural BMPs.this manual covers site selection, sample size estimation, sampling,
and results evaluation and presentation. Contact the National Service Center for
Environmental Publications (800) 490-9198; or see:
http://www.epa.gov/owow/nps/agfinal.html.
03 Volunteer Stream Monitoring: a methods manual. U.S. Environmental
Protection Agency (1997). This document covers the basic elements of stream
monitoring, how to conduct a watershed survey, how to measure various water
quality components, and how to manage and present monitoring data. See:
http://www.epa.gov/owow/monitoring/volunteer/stream/.
URBAN NFS DOCUMENTS
Best General Web Addresses
5 American Society of Civil Engineers (ASCE) National Stormwater BMP
Database. Contains information on the effectiveness of urban BMPs in removing
pollutants from urban runoff. Only studies which conform to established protocols
are entered into the database. See: www.bmpdatabase.org.
H Center for Watershed Protection. Contains model ordinances, BMP
effectiveness information, and other information on urban pollution and controls,
with a concentration on watershed-based approaches. See: www.cwp.org.
H City of Fort Worth. Texas: Municipal and County Storm Water Programs.
This web site contains hot links to municipal and county government stormwater
programs around the United States. There is also a description of Fort Worth's
NPDES Stormwater Phase I permit requirements, including construction and new
development. See: http://ci.fort-worth.tx.us/dem/stormcontacts.htm.
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URBAN NFS DOCUMENTS: Best General Web Addresses
B Low Impact Development Institute Web Site. This web site contains general
information on Low Impact Development BMPs and case studies as well as hot links
to related organizations and projects. See: www.lbwimpactdevelopment.org.
H Nonpoint Education for Municipal Officials (NEMO). NEMO provides
municipal officials with technical assistance and training in linking land use to water
quality. See: www.lib.uconn.edu/CANR/ces/nemo/.
H Terrene Institute. This organization has produced a number of very good
general publications for use by the public as well as by watershed and local managers
in addressing issues and problems concerning urban and other sources of nonpoint
source pollution. See catalog on www.terrene.org. To order call (800) 726-4853
or e-mail terrinst@aol.com.
Citizens/Homeowners Guides
03 Bo/book: A Guide to Reducing Water Pollution at Home.* Chesapeake Bay,
Inc. and Alliance for the Chesapeake Bay (March 1993). A lay publication to create
awareness and actions to reduce water pollution. Homeowners are the target
audience for this document. Call: (410) 377-6270.
& Bayscapes: Environmentally Sound Landscapes for the Chesapeake Bay.
Alliance for the Chesapeake Bay (1994). A set of comprehensive fact sheets which
contain detailed actions homeowners can take to implement environmentally
friendly landscaping. Addresses pesticides, nutrients, erosion control, pesticides, and
habitat diversity. Contains checklists for each fact sheet. Call: (804) 775-0951 or
(717)236-8825.
C3 Clean Water in Your Watershed: A Citizens Guide to Watershed
Protection.* Terrene Institute in cooperation with U.S. Environmental Protection
Agency Region 6 (October 1993). An easy to understand and well illustrated guide
to help citizens work with local, state, and federal government agencies to design
and implement successful watershed protection and restoration projects.
Step-by-step recommendations are provided. Call (800) 726-4853; e-mail
terrinst@aol.com; see www.terrene.org..
m HANDLE WITH CARE: Your Guide to Preventing Water Pollution.* Terrene
Institute (1991). A simple but effective citizens' guide to problems due to rainfall and
runoff in urban areas and what citizens and homeowners can do to reduce the
harmful effects of runoff on water quality. Call (800) 726-4853; e-mail
terrinst@aol.com; see www.terrene.org
H Turning the Tide A Citizen's Guide to Reducing Nonpoint Source
Pollution* Harborwatch, Inc. and South Carolina Department of Health and
Environmental Control. A concise brochure that describes urban nonpoint pollution
and what actions citizens can take to reduce pollution in urban areas. Includes
checklists. Call: (803) 734-5300.
Construction Controls
ffl Storm Water Management for Construct/on Activities: Developing
Pollution Prevention Plans and Best Management Practices. U.S. Environmental
Protection Agency (EPA 833-R-92-OOI) (October 1992). EPA's guidance on how to
prepare a stormwater pollution prevention plan for NPDES Storm Water Phase I
construction activities. Includes erosion and sediment control BMPs and other
control require- ments for construction sites, from site evaluation to final stabilization.
Contact NSCEP: (800) 490-9198.
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URBAN NFS DOCUMENTS: Funding
funding
03 Catalog of Federal Funding Sources for Watershed Protect/on (2nd edition).
US. Environmental Protection Agency (EPA 841 -B-99-003) (December 1999). Provides
a comprehensive summary of federal grant and loan programs that be used at the local
level to support watershed projects. Also contains references to other publications as
well as web sites on funding assistance. Contact NSCEP: (800) 490-9198.
B Clean Water State Revolving Loan Web Site. A one-stop-shopping site for
learning about the State Revolving Loan Fund (SRF). Includes information on
eligibility, repayment, and restrictions. See: www.epa.gov/OWM/finan.htrn.
03 A State and Local Government Guide to Environmental Program Funding
Alternatives. U.S. Environmental Protection Agency (EPA 841-K-94-001) (January
1994). Provides an overview of traditional (nongovernment) funding mechanisms and
innovative approaches to fund environmental programs. Contact NSCEP: (800)
490-9198.
General NPS Controls for Urban and Urbanizing Areas
03 Fundamentals of Urban Runoff Management: Technical and Institutional
Issues*. R.R. Homer, J.J. Skupien, E.H. Livingston, and H.E. Shaver (August 1994).
Terrene Institute in cooperation with U.S. Environmental Protection Agency.
Part I contains clear and concise runoff and pollutant impact assessment and
technical information on structural runoff controls in a logical sequence.
Nonstructural alternatives are cleverly imbedded in Part II, which addresses
institutional structures and frameworks which will help ensure implementation and
continuance of control programs. Call (800) 726-4853.
03 Guidance Specifying Management Measures for Sources ofNonpoint
Pollution in Coastal Waters. U.S. Environmental Protection Agency (EPA
840-B-92-002) (January 1993). Chapter 4 contains a description of water quality
problems caused by urban nonpoint source. Documents pollution as well as
management measures that represent performance expectations for urban controls to
be implemented in states with approved coastal zone management programs. Manage-
ment practices (referred to in other documents as "best management practices (BMPs)"
are described that can be used to economically achieve the performance expectations.
Contact NSCEP: (800) 490-9198; and see: http://www.epa.gov/owow/nps/MMGI.
03 Stormwater Strategies: Community Responses to Runoff Pollution.* Natural
Resources Defense Council (May 1999). This study highlights some of the most
effective and efficient watershed and municipal examples of nonpoint source and
stormwater control programs and activities in the country. By example, communities
can use these case studies in developing and implementing their own runoff control
programs. See: www.nrdc.org.
03 Watershed Protection Techniques* Center for Watershed Protection, Silver
Spring, MD. A periodic bulletin on urban watershed restoration and protection tools
including runoff management practices or BMPs. Contains often-cited technical
notes that describe, compare, and evaluate urban controls as well as the effects of
runoff both with and without controls. See: www.cwp.org.
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APPENDIX 6-A: Best Nonpoint Source Resources
URBAN NFS DOCUMENTS: Institutional/Program Development
Institutional/Program Development
(Includes Utility Management Systems)
ffl Institutional Aspects of Urban Runoff Management: A Guide for Program
Development and Implementation* E.H.Livingston, H.E.Shaver,R.R.Horner,and
J.J. Skupien (May 1997). The Watershed Management Institute, Inc. in cooperation
with U.S. Environmental Protection Agency. A comprehensive review of the
institutional framework of successful urban runoff management programs at city,
county, regional, and state levels of government. Recommendations are provided
(based on surveys) that can help in all aspects of urban runoff program development
and management. Contact WMI at: (850) 926-5310.
Monitoring
03 Monitoring Guidance for Determining Effectiveness of Nonpoint Source
Controls. U.S. Environmental Protection Agency (EPA 841 -B-96-004) (September
1997). This guidance addresses design of monitoring programs to assess water
quality to determine impacts of nonpoint sources and effectiveness of best
management practices used as controls. Contact NSCEP: (800) 490-9198.
£3 Techniques for Tracking, Evaluating, and Reporting the Implementation of
Nonpoint Source Control Measures — Urban Field Test Version. U.S.
Environmental Protection Agency (EPA 84I-B-937-OI I) (July 1998 - Update to Final
in progress). Helps local officials focus limited resources by establishing statistical
sampling to assess, inspect, or evaluate a representative set of BMPs, erosion and
sediment controls, and on-site wastewater treatment systems. For more information,
contact Rod Frederick at (202) 260-7054.
New Development Controls
03 Better Si'te Design: A Handbook for Changing Development Rules in Your
Community.* The Center for Watershed Protection (August 1998). (See list for
Site-Level Planning.) See: www.cwp.org.
ffl Caltran's Storm Water Quality Handbook. This handbook is intended to
provide background information on Caltrans' (California Department of
Transportation) program to control water pollution and to standardize the process
for preparing and implementing the Water Pollution Control Program (WPCP) and
Storm Water Pollution Prevention Program (SWPPP). Caltrans requires contractors
to prepare and implement a program to control water pollution during the
construction of all projects. See: http://www.dot.ca.gov/hq/construc/stormwater.html.
03 Economic Benefits of Runoff Controls. U.S. Environmental Protection Agency
(EPA 841 -S-95- 002) (September 1995). This document contains a description of
studies that document increases in property values and rental prices when properly
designed runoff control facilities are used as visual amenities. Contact NSCEP: (800)
490-9198.
E3 Environmental Land Planning Series: Site Planning for Urban Stream
Protection. T. Schueler (December 1995). Prepared by the Center for Watershed
Protection for the Metropolitan Washington Council of Governments, Washington,
DC. (See list for Site-Level Planning.) See: www.cwp.org
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URBAN NFS DOCUMENTS; New Development Controls
O Stormwater BMP Design Supplement for Cold Climates* Center for
Watershed Protection in cooperation with U.S. Environmental Protection Agency
(December 1997). This manual addresses some of the unique challenges of design
and maintenance of runoff BMPs in cold climates and recommends strategies to
make BMPs in these regions more effective. See: www.cwp.org.
03 Texas Nonpoint Source Book — BMPs. Contains stormwater pollution manage-
ment information for public works professionals and other interested parties in the State
of Texas. Also contains information on watershed assessment and design and imple-
mentation of nonstructural and structural BMPs. See: http://www.txnpsbook.org.
£3 Washington State Department of Ecology Website. This website contains
information on Washington State's Nonpoint Source program and NPDES storm-
water programs. Refer to the publications list. The draft BMP manual for Western
Washington State is worth reviewing to learn about Washington's approach to
protecting the hydrological regime of streams. Also noteworthy are "Planning as
Process: A Community Guide to Watershed Planning" (Ecology Publication
#99-01-WQ); and "Watershed Urbanization and the Decline of Salmon in Puget
Sound Streams" by Dr. Chris May. The Community Guide is a useful reference for
community involvement in the planning process. The paper by Chris May draws a
link between urbanization and salmonid impacts. See:
http://www.wa.gov/ecology/biblio/991 I .html.
£0 2000 Maryland Storm Water Design Manual. Volumes I and //.Volume I
contains information on BMP siting and design on new development sites to comply
with the state's 14 stormwater performance standards. Stormwater credits for
innovative design are a significant addition. Volume 2 contains detailed technical
information including step-by-step design examples. See: www.mde.state.md.us.
Notable State Manuals and Guidance Manuals
CQ Erosion and Sediment Control Planning and Design Manual. Field Manual
and Inspector's Guide* North Carolina Department of Environment, Health,and
Natural Resources, Division of Land Resources. Addresses planning design,
implementation, and inspection of erosion and sediment control BMPs. Call: (919)
733-4574.
£3 Sediment and Stormwater Management Certified Construction Reviewer
Course and Associated Delaware State and DOT Standards/Specifications.*
State of Delaware, Delaware Department of Natural Resources and Environmental
Control, Division of Soil and Water Conservation. Contains descriptions of
Delaware's erosion and sediment control and runoff control BMPs as well as their
certification requirements for contractors. Call: (302) 739-441 I.
£Q Tennessee On-line BMP manual. City of Knoxville (under development). This
draft on-line erosion and sediment control manual provides information on the
design, inspection, and maintenance of structural and nonstructural BMPs that are
used in Knoxville. The manual is similar to stormwater guidance prepared for the
California Stormwater Quality Task Force and Caltrans, See:
www.ci.knoxville.tn.us/reports/bmp manual/index.htm.
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APPENDIX 6-A: Best Nonpoint Source Resources
URBAN NFS DOCUMENTS: Operation and Maintenance
Operation and Maintenance
S3 Operation Maintenance and Management of Stormwater Management
Systems.* E.H. Livingston, H.E. Shaver,J.J. Skupien, and R.R. Horner (August 1997).
Watershed Management Institute in cooperation with U.S. Environmental Protection
Agency. Note: Includes Stormwater Management Inspection Forms as a separate
supplement. The manual contains a comprehensive review of the technical, educational,
and institutional elements needed to assure that stormwater management systems are
designed, built, maintained, and operated properly during and after construction. Fact
sheets on 13 commonly used BMPs are included. Call: (850) 926-5310.
Qrdi
inances
03 Model Ordinances to Protect Local Resources. U.S. Environmental Protection
Agency (November 1999). EPA has developed a web site that contains printable and
create-your-own ordinances as well as links to other web sites. Ordinances include
aquatic buffers, erosion and sediment control, open space development, stormwater
control operation and maintenance, illicit discharges, post-construction runoff,
source water protection, and miscellaneous ordinances (golf courses, etc.). See:
http://www.epa.gov/owow/nps/ordinance/.
Restoration
CQ Izaak Walton League Save Our Streams Program (January, 1995). Includes
A Citizen's Streambank Restoration Handbook, a video, and personal assistance.*
A primer to help citizens, government planners, and decisionmakers understand
channelization and streambank restoration techniques. Includes case studies, an
annotated bibliography, and restoration contacts. Call: (800) BUG-IWLA.
CQ Restoring Streams in Cities: A Guide for Planners, Policymakers, and
Citizens. Ann Riley (1998). This book contains a logical sequence of land-use
planning, site design, and watershed restoration measures along with stream channel
modifications and floodproofing strategies that can be used in place of destructive
and expensive public works projects. Contact Island Press' distribution center at P.O.
Box 7, Covelo, CA 95428, phone: (800) 828-1302, fax: (707) 983-6414,
ipwest@islandpress.org.
£3 Stream Corridor Restoration Principles, Processes, and Practices. Federal
Interagency Stream Restoration Working Group (EPA 841-R-98-900) (October
1998). A cooperative effort of 17 federal agencies resulted in this compendium of
stream corridor restoration expert advice and field-tested methods. A CD-ROM is
also available. Contact NSCEP: (800) 490-9198.
HH Urban Stream Restoration: A Video Tour of Ecological Restoration
Techniques. * Includes information on six urban stream restoration sites with
detailed instructions and graphic illustrations. Includes bioengineering stabilization
techniques, recreating channel shapes and meanders, daylighting of buried creeks,
and vegetated flood controls. Led by Ann Riley, Executive Director .of the
Waterways Restoration Institute in Berkeley, CA. See: www.noltemedia.com.
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URBAN NFS DOCUMENTS: Site — Level Planning
Site — Level Planning
03 Better Site Design: A Handbook for Changing Development Rules in Your
Community. The Center for Watershed Protection (August 1998). This handbook
was prepared for local planners, engineers, developers, and officials to help them
understand development principles that can be used to create environmentally
sensitive, economically viable, and locally appropriate development. See: www.cwp.org.
03 Conservation Design for Stormwater Management.* The Environmental
Management Center of the Brandywine Conservancy, Delaware Department of
Natural Resources and Environmental Control (September 1997). This document
describes methodologies for configuring new developments to increase water
quality protection and pervious surfaces by reducing lot sizes and thereby increasing
green space and common use areas. Call: (302) 739-4411.
03 Environmental Land Planning Series: Site Planning for Urban Stream
Protection. T. Schueler (December 1995). Prepared by the Center for Watershed
Protection for the Metropolitan Washington Council of Governments, Washington,
DC. This series is for all audiences, presenting a clear and understandable
description of the significance of imperviousness in a watershed. Also describes
planning strategies to protect urban streams by reducing imperviousness and
increasing green space. See www.cwp.org.
03 Low-Impact Development Design Strategies. Prince Georges County,
Maryland (EPA 841 -B-00-003) (January 2000). Low-Impact Development
Hydrologic Analysis. Prince Georges County, Maryland (EPA 841 -B-00-002)
(January 2000). These two documents describe LID principles, programmatic
considerations, and design strategies, and give an example of an analytic and
computational procedure to use in designing appropriate runoff treatment systems.
The strategies document (003) was prepared for local planners, engineers,
developers, and officials to describe how to develop and implement LID methods
from an integrated design perspective. The hydrologic analysis document (002) is a
companion technical document that contains a methodology that can be used to
estimate changes in site hydrology due to new development and also to design
appropriate treatment systems to maintain the predevelopment hydrology of the
site. Contact NSCEP: (800) 490-9198.
Watershed Planning
Q3 Rapid Watershed Planning Handbook. The Center for Watershed Protection
(October, 1998). This handbook was written to assist watershed associations and
local governments in developing effective and low-cost watershed protection plans.
Eight steps are described in detail including how to identify and classify
subwatersheds, protect and restore water resources, and evaluate progress. The
document emphasizes resource identification, evaluation, and planning. See:
www.cwp.org.
03 Technical Assistance and Team Training in Linking Land Use to Water
Quality. Nonpoint Education for Municipal Officials (NEMO). NEMO provides
municipal officials with technical assistance and training in linking land use to water
quality. See: www.lib.uconn.edu/CANR/ces/nemo/
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APPENDIX 6-A: Best Nonpoint Source Resources
URBAN NFS DOCUMENTS: Watershed Planning
ffl Urbanization and Streams; Studies of Hydrologic Impacts. U.S.
Environmental Protection Agency (EPA-R-97-009) (December 1997). This report
includes references and case studies that document the impacts of urbanization on
water quality, habitat, and aquatic biota. Contact NSCEP.
633 A Watershed Approach to Urban Runoff: Handbook for Decisionmakers*
Terrene Institute in cooperation with U.S. Environmental Protection Agency Region
5, March 1996. An informative primer for local decisionmakers and watershed
organizations on assessing the water quality of watersheds, identifying contributing
sources, and prioritizing watershed resources to implement effective nonstructural
and structural BMPs. Summarizes BMPs and lists resources to obtain additional
information. Call (800) 726-4853; e-mail terrinst@aol.com; or see www.terrene.org.
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CHAPTER 7
Management Techniques
Within the Lake or Reservoir
Introduction
Like medical prescriptions, lake and reservoir management techniques have bene-
fits, side effects, and limitations. None is suitable for every lake, for all problems,
or even for a specific problem under varying circumstances. With that warning
delivered, what can the reader expect to gain from this chapter?
• Insight into the ecological and management principles involved in
crafting a management plan;
• Understanding of the range of available lake and reservoir restoration
and management methods;
• An appreciation of the many factors involved in choosing the most
appropriate technique(s); and
• Knowledge of the ecological basis for specific methods, including their
applicability to specific problems, how they work, their advantages and
disadvantages, and approximate costs.
Principles of Management
Restoration vs. Management vs. Protection
Although the terms restoration, management, and protection all have different
meanings, they are often used interchangeably in dealing with lakes. The distinc-
tions and overlap among them are important, however, and should be emphasized
when planning a program to address lake problems.
Lake restoration is the use of ecologically sound principles (Chapter 2) to
attempt to return a lake or reservoir to as close to its original condition as possi-
ble. Restoration suggests that some previously existing condition is to be re-
gained. Sometimes the lake can be made even better than the original condition,
which is less restoration than management.
Management is defined as improving the lake or reservoir to enhance
stated uses, such as water supply, swimming, fishing, or wildlife habitat. Manage-
ment may or may not involve restoration of past conditions, and might better be
described as rehabilitation (Cooke, 1999).
Restoration: Use of
ecologically sound principles
to attempt to return a lake or
reservoir as close to its
original condition as
possible.
Management: Improving
the lake or reservoir to
enhance stated uses, such as
water supply, swimming,
fishing, or wildlife habitat.
Protection: The prevention
of adverse impacts.
r
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Managing Lakes and Reservoirs
Once restored or managed to the desired condition, a lake will usually re-
quire continued management to stay in that condition. This may involve repeated
application of the technique that achieved the desired lake condition in the first
place, or using different techniques to prevent undesirable changes. Here man-
agement grades into protection, defined as the prevention of adverse impacts
(see Chapter 9).
We often think of protecting pristine lakes, but damaged lakes can also be
protected by developing regulations that prohibit practices believed to threaten
the lake. Hand pulling non-native plants can also be protective, just like pulling
weeds from a garden. While removing vegetation can be a management tech-
nique, in this case it is protective: preventing the spread and dominance of an un-
desired species.
The difference between restoration, management, and protection is there-
fore a function of past and present lake conditions (Chapter 4) set in the context
of goals for the lake's desired condition (Chapter 3). Although applicable tech-
niques are basically the same, restoration and protection differ according to spe-
cific objectives. Management is the approach most used on U.S. lakes.
Selection of Goals
Successful management must be guided by a clear statement of goals and priori-
ties (refer to Chapter 3). What are the intended uses of the lake; are any more
important than others? Optimal conditions for swimming, boating, fishing, and wa-
ter supply rarely exist in the same lake, although all may be accommodated to
some degree. Balancing conditions and uses may be an appropriate goal, but not
all lake management uses are completely compatible (Wagner and Oglesby, 1984),
and goals must be set accordingly.
The choice of lake management techniques depends on water uses and
management goals. Some techniques enhance some uses but not others. For ex-
ample:
• Many herbicides cannot be applied to drinking water supplies, even
though they control nuisance vegetation.
• Aeration that destratifies a lake may harm coldwater fisheries, even
though oxygen concentrations increase lakewide and algae decline.
Definition of Problems
Normally, management goals are based on supporting specific water uses. This
typically involves combating a variety of problems (see Chapter 4 for a full discus-
sion of defining problems). All 11 of the general issues listed in Table 7-1 are com-
mon, but this chapter will emphasize controlling nuisance algae and rooted plants,
the two most common management objectives.
v Algal blooms or rooted plant infestations: Many complex
processes interact to cause these problems. To effectively control algae,
you must understand the quality of water entering a lake and the cycling
of nutrients within the lake. Rooted plants flourish in many lakes without
significant inputs from the watershed, just because of the nature of the
sediments present when the lake was formed.
216
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Some of the other problems referred to in this chapter can be ad-
dressed by the same techniques applied to algae and vascular plant control.
Table 7-1.— Lake and reservoir problem definition.
GENERAL ISSUE 'X
1 . Nuisance algae
2. Nuisance vascular plants
3. Sediment buildup
4. Non-algal color and turbidity
5. Anoxia and related issues
6. Acidification
7. Toxic substances
8. Pathogens
9. Undesirable fisheries
1 0. Animal nuisances
1 1 . User conflicts
v! POSSIBLE SPECIFIC PROBLEMS
Loss of water clarity, taste/odor, algal toxicity, oxygen
fluctuations and depression, disinfection byproduct
formation upon chlorination, habitat impairment, human
health risks
Dense rooted or floating growths, dominance by aggressive
introduced species, organic sediment accumulation, oxygen
fluctuations and depression, habitat alteration
Loss of depth, undesirable sediment qualify, sediment-water
interactions (link to nutrient loading), nabitat impairment
Observable color from humic substances or other agents,
high levels of particulates in suspension, loss of water clarity,
aesthetic impairment
Lack of oxygen, buildup of ammonia, hydrogen sulfide,
carbonaceous gases, iron, manganese and phosphorus
through anaerobic reactions, habitat impairment (usually a
product of above problems)
Reduced pH, fluctuating pH, pH-mediated water quality
changes, habitat impairment
Excessive levels of metals, pesticides, or organic
metabolites, habitat impairment, human health risks
Excessive levels of bacteria, viruses, or other pathogens,
aquatic fauna and human health risk
Small population size, undesirable size distribution,
predator-prey imbalances, invasive or disruptive species,
poor fish condition (e.g., weight vs. length, diseases),
resuspension of bottom sediments
Excessive numbers of mosquitos, midges, other insects,
ducks, geese, other waterfowl, leeches, zebra mussels, other
undesirable fauna, swimmer's itch, human health risks
Interference among uses and users, including human vs.
non-human uses, passive vs. active human uses,
overcrowding, noise, and water-level conflicts
^ Excessive sedimentation usually comes from either erosion in
the watershed or organic matter (algae and vascular plants) produced in
the lake. Once sediment accumulates, it may interact with the water col-
umn and accelerate eutrophication.
v Nonalgal color and turbidity can be used to control algae and
rooted plants, but high levels of either generally have undesirable effects on
water supply and recreational uses, and may also impair wildlife habitat.
V/VflOX/a is the absence of oxygen. Decaying algae, vascular plants, and
other organic matter may use more oxygen than the atmosphere can sup-
ply, especially in bottom waters far removed from the atmosphere. Anoxic
conditions often release phosphorus, iron, manganese, and sulfides from
sediments; this may eventually establish a self-supporting cycle of excess
production and decay. At that point, watershed inputs may no longer con-
trol in-lake conditions.
Anoxia: The absence of
oxygen.
217
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Managing Lakes and Reservoirs
Problems w/f/i acidification, toxic substances, and patho-
gens are largely watershed issues, and should be dealt with on that level
(see Chapter 6). However, if controlling the source and trapping pollutants
in the watershed do not succeed, techniques may be applied within the
lake or reservoir to minimize their impact.
Poor fishing may be rooted in several causes, ranging from habitat im-
pairment within the lake to overfishing and poor stocking practices. Man-
aging for an optimal fishery involves many choices and requires a
thorough understanding of the physical, chemical, and biological features
of the lake — plus the ability to deal effectively with people.
Nuisance fauna such as geese and zebra mussels may threaten hu-
man health, annoy lake users, or disrupt ecological conditions for wildlife.
Users and agencies may differ about when to declare nuisance conditions,
but when they decide to address this problem, they must take care not to
create a greater hazard. Nuisance fauna and fishing problems involve a hu-
man element that can cause user conflicts.
User conflicts may arise over desired lake conditions, but more often,
conflicts arise over access to the lake, allocation of space, or mutually ex-
clusive uses occurring at the same time.
• The conflict of motorized (especially personal) watercraft with
other water-based recreation is reaching the same status as
excessive algae or rooted plants in surveys of lake management
needs.
• The need for water in developing areas (for residential and other
uses) is also competing more intensely with the preservation of
aquatic habitat.
The techniques for dealing with these problems are as much social
science as aquatic science, but lake managers frequently have to make
judgments that affect how people use the lake, so this issue is most perti-
nent to lake management.
Understanding Existing and Potential
Future Conditions
Not all lakes are created equal. Differences in origin, climate, and watershed fea-
tures predispose lakes to certain conditions. When planning a lake management
program and selecting management techniques, it is essential to completely un-
derstand existing conditions and limits to improvement.
Chapter 2 provides insight into the ecological principles upon which lake
management is based, while Chapter 5 describes tools for predicting results.
Chapter 4 addresses the information needed for characterizing problems and
evaluating causes and effects — a key step between understanding lake ecology
and making specific predictions.
While sustained management can accomplish major feats, it has both theo-
retical and practical limits. For a variety of reasons, some lakes cannot be ade-
quately protected, or users' expectations are not realistic.
218
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• A survey of Lake Champlain users (New York and Vermont) revealed
that they expect clearer water than has ever been recorded for that
lake (Garrison and Smeltzer, 1987).
• In the Upper Midwest, people expect much clearer water for more
northern lakes (Heiskary, 1989), thus affecting management goals.
The origin of a lake must be considered in managing it. Lakes are created by
natural or human forces, or by both combined. People-built lakes range from
shallow ponds and impoundments predisposed to infestation by rooted plants to
large, deep reservoirs that detain river water long enough to foster algal blooms
when enough nutrients are present. Many impoundments were never deep, clear,
infertile lakes, and must be managed just to maintain them, as both natural and
cultural forces cause them to fill in.
The depth of a lake, its morphometry, its division into multiple layers, and
how often these layers mix are all extremely important to a lake's ecology, and
often dictate the selection of management techniques. Although shallow (< 15 ft)
lakes can stratify if light does not penetrate very far, usually a lake must be at least
20 feet deep before stratification becomes strong and prolonged. Lake depth in-
fluences the area that can support rooted plants, the internal cycling of phospho-
rus, flushing characteristics, and the nature of the fish community.
Some lakes are naturally fertile, largely because of the geology and soils
around them (Rohm et al. 1995). Some ecoregions have richer, more erodible
soils, and higher annual precipitation; these factors increase sediment and nutri-
ents in those lakes, even without considering human uses of the land.
High fertility isn't always undesirable; management for fish production re-
quires a substantial food base. Some lakes and reservoirs are so infertile they may
not support many fish. Management might include adding nutrients to stimulate
algae growth and the ensuing development of game fish populations, if that is a
primary goal and regulatory agencies will permit it.
Again, goals and priorities must be clearly stated if management techniques
are to be selected correctly. Targeting balanced conditions and uses is usually the
best course of action.
To understand and solve many lake problems, we must move beyond nutri-
ents into ecosystem energetics (Kortmann and Rich, 1994). The flow of nutrients
is but one aspect of energy and its transformations. Energetics plays a major role
in nitrogen transformations and recycling of phosphorus, which in turn influence
the amount and types of algae present. The position of the lake along a gradient
from heterotrophy (dependence on the addition of organic matter) to autotro-
phy (dependence upon internally generated organic matter) significantly influ-
ences how the lake will react to management actions.
With an understanding of current and potential lake conditions, lake manag-
ers can evaluate management goals in terms of ecology, economics, and ethics.
• Is a proposed option consistent with the ecological function of the
aquatic system?
• Is the proposed approach affordable, for both the short and long
term?
• Does an action treat all lake users (human and otherwise) fairly?
« Can it be considered ethical from all rational viewpoints?
Morphometry:
Measurement of the physical
shape and depth of a lake.
Ecosystem energetics:
The flow of energy through
trophic levels, including
inputs to lakes from the
watershed (such as leaves or
insects) and the
transformation of that energy
within the lake.
219
-------
Managing Lakes and Reservoirs
Developing a Watershed Management Program
Oeldom can a single
•technique handle all
• problems faced by a
.single lake, and in many
cases more than one
technique must be used
to successfully address
even a single problem
such as excessive algae
or rooted plant growths.
.
Watershed management is the subject of Chapter 6; from a long-term perspec-
tive, the condition of a water body is dictated primarily by the quality and quantity
of water entering it. Although biological interactions, sediment release of nutri-
ents, and basin morphometry may all affect the lake, it is clear that nearly all at-
tempts at lake management will be overwhelmed by continued high loading of silt,
organic matter, and nutrients from the watershed. Watershed management is
therefore a prerequisite for lake management or protection.
But watershed management may not be the sole answer. Once rooted plants
infest a lake, no amount of watershed management is likely to eliminate them.
Even if the flow of phosphorus to a lake is drastically reduced, internal recycling
may maintain excessive algal production for many years.
In-lake techniques then become the next step in supporting lake uses, even if
on a maintenance basis. An in-lake management program is meant to comple-
ment watershed management, however, not replace it.
In-lake Management: Matching
Options to Problems
Lake management techniques can be grouped several ways. Table 7-2 simply lists
them alphabetically, but alternative listings (described further in this chapter) in-
clude characterization as a physical, chemical, or biological technique, and group-
ing by problems to which they can be applied.
The list of available options in Table 7-2 is not very long (although subcate-
gories would multiply them fivefold). Do not be deceived by the brevity of the list,
however; properly applying these techniques will provide enough power to ad-
dress almost all known lake problems.
Seldom can a single technique handle all problems faced by a lake, and in
many cases more than one technique must be used to successfully address even a
single problem such as excessive algae or rooted plant growths. These combina-
tions and the scale and intensity of their application offer a wide range of possible
management programs that can be tailored to a lake's unique properties.
Perhaps the greatest value of using professional help with lake problems is
the professional's expertise in evaluating if a technique is appropriate, given the
nature of the problem and the known (and potential) conditions and constraints.
Many factors must be considered (Table 7-3); failure to address them can affect
the success and/or cost of the management program.
Questions to ask when evaluating each technique in relation to a given
problem:
• How effective is this technique likely to be?
• How rapidly will it achieve results and how long will those results
last?
• What desirable or undesirable side effects might be expected?
• How much will it cost over the duration of the management period?
• Will a balance of appropriate uses be achieved by the proposed
action (s)?
220
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Success is a matter of matching the right technique(s) to the problem; this
requires background information best obtained from a thorough diagnostic/feasi-
bility study. It's always desirable to rapidly achieve the targeted results, but their
longevity is usually more important. Longevity plays a large role in determining
long-term costs, and since very few justifiable management programs are devel-
oped with only the short term in mind, this is an important consideration.
Table 7-2.— General management options within lakes and reservoirs.
TECHNIQUE
1 . Aeration or oxygen addition
2. Artificial or augmented circulation
3. Biocidal chemical treatment
4. Biomanipulation
5. Bottom sealing
6. Chemical sediment treatment
7. Dilution and/or flushing
8. Dredging
9. Dye addition
1 0. Hydroraking or rotovation
1 1 . Harvesting, pulling, or cutting
12. Nutrient inactivation
13. Nutrient supplementation
1 4. Other chemical treatments
15. Partitioning for pollutant capture
16. Rules and regulations
1 7. Selective withdrawal
18. Water level control
DESCRIPTIVE NOTES
Mechanical maintenance of oxygen levels.
Water movement to enhance mixing and/or
prevent stratification.
Addition of inhibitory substances intended to
eliminate target species.
Facilitation of biological interactions to alter
ecosystem processes.
Physical obstruction of rooted plant growths and/or
sediment-water interaction.
Addition of compounds that alter sediment features
to limit plant growths or control chemical exchange
reactions.
Increased flow to dilute or minimize retention of
undesirable materials.
Removal of sediments under wet or dry conditions.
Introduction of suspended pigments to create light
inhibition of plant growth.
Disturbance of sediments, often with removal of
rooted plants, to disrupt growth.
Reduction of plant growths by mechanical means,
with or without removal from the lake.
Chemical complexing and usually precipitation of
nutrients, normally phosphorus.
Addition of nutrients to enhance productivity or alter
nutrient ratios to affect algal composition.
Addition of chemicals to adjust pH, oxidize
compounds, flocculate and settle solids, or affect
chemical habitat features.
Creation of in-lake areas, such as forebays and
created wetlands, to capture incoming pollutants.
Restrictions on human actions directed at
minimizing impacts on lakes and lake users.
Removal of targeted waters for discharge
(undesirable features such as high nutrients) or
intake (desirable features such as low algae).
Drying or flooding of target areas to aid or
eliminate target species.
221
-------
10
to
to
Table 7-3.— Factors in selecting management techniques.
TECHNIQUE
1 . Aeration or
oxygen
addition
2. Artificial or
augmented
circulation
APPLICABLE USES
OF THE TECHNIQUE
» Algal control by
reduced phosphorus
release From sediment
* Lowered dissolved Mn
and Fe levels
* Improved fish habitat
* Creation of deeper
zooplankton refugia
(places where
predation is limited by
light or temperature)
» Avoidance of
stagnation
» Destratification
* Increased mixing
» Enhanced surface
aeration
* Disruption of algal
mats and scums
PRIMARY
INFORMATION
NEEDS
*Hypolimnetic oxygen
demand
* Sediment oxygen
demand
* Relative resistance to
thermal mixing
»Area and depth of
epilimnion and
hypolimnion
* Annual phosphorus
release rate for
sediment
* Concentrations of
forms of P, Fe, Mn
»Area and volume of
water to be moved
* Rate of desired
movement/oxygen
demand
* Relative resistance to
thermal mixing
* Physical impediments
to mixing
KEY
WATER ISSUES
» Restrictions on
destratificalion
* Longevity of effects
* Possible water quality
effects of mixing
KEY
SEDIMENT ISSUES
* Longevity of effects
» Potential for
resuspension
» Potential for
resuspension
KEY
BIOLOGICAL
ISSUES
» Potential for enhanced
habitat
* Potential for gas
bubble disease in
which deadly gas
bubbles form in a
fish's blood stream
* Potential for thermal
impacts through
mixing
» Potential to
disseminate
undesirable species
* Potential to disrupt life
cycles of desirable
species
KEY
USE ISSUES
» Potential for
interference with
recreation
» Potential for
interference with
recreation
» Effects on water
supply qualify
KEY
COST FACTORS
» Equipment and
oxygen costs
* Power supply
* Installation costs
* Long-term operational
costs
* Monitoring program
* Equipment costs
» Power supply
* Installation costs
» Long-term operational
costs
»Monitoring program
-------
CO
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
3. Biocidal
Chemical
Treatment
4. Bio-
manipulation
APPLICABLE USES
OF THE TECHNIQUE
» Algal control
* Vascular plant control
* Insect pest control
*Fish reclamation
* Algal control
'Vascular plant control
* Fish control
* Nuisance fauna
abatement
* Habitat enhancement
PRIMARY
INFORMATION
NEEDS
»Pond bathymetry and
volume
* Flushing rate (by
month or season)
*Choice of chemical
»Form of chemical to
be used (pellets vs.
liquid)
» Chemical concentra-
tion needed
*Amount of chemical to
be used
* Duration of exposure
to chemical needed
»Timing and frequency
of treatments
* Outlet control features
» Biological inventory of
lake
» Habitat evaluation for
existing and proposed
conditions
» Necessary stocking/
planting or removal
rate
* Ability to control inlets
and outlets
KEY
WATER ISSUES
» Persistence of
chemical and
degradation products
» Effects on oxygen
levels
» Potential for nutrient
releases
» Other indirect water
quality impacts
» Possible effects of
introduced species on
water quality
KEY
SEDIMENT ISSUES
»Accumulation of
contaminants
* Accumulation of
organic matter
* Interactions of
introduced species
and sediments
KEY
BIOLOGICAL
ISSUES
»Anticipated impacts to
target and non- target
plant species
* Potential migration of
chemical into
hydraulically con-
nected wetland areas
* Association of fauna
with area to be
treated
» Presence of protected
species
» Distance downstream
at which chemical
can be detected
» Possible impacts to
downstream biotic
assemblages
» Uncertainly of
biological interactions
» Longevity of effects
*Migration to
unintended
habitats/lakes
'-•••••- KEY :.-.:•:;•.•
USE ISSUES
» Downstream flow
restrictions
* Use restrictions
following treatment
(severity and duration)
* Alternative water
supplies
* Public perception of
risk of exposure to
chemical
» Potential for much
dead and decaying
vegetation
* Interaction of
introduced species
with lake users
/•-;•:,:':• : KEY ::V:'?. •- •'
COST FACTORS
*Cost of chemical
» Application method
* Application labor
* Monitoring program
* Interaction of
introduced species
with lake users
*Cost of removal of
individuals or
species
*Cost of habitat
alteration
* Monitoring program
-------
10
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
5. Bottom
sealing
6. Chemical
sediment
treatment
7. Dilution
and/or
flushing
APPLICABLE USES
OF THE TECHNIQUE
» Reduced
sediment-water
interactions
* Algal control
» Rooted plant control
* Improved recreational
appeal
» Reduced
sediment-water
interactions
* Reduced phosphorus
release from sediment
* Algal control
* Reduced detention
time
» Pollutant concentra-
tion reduction
» Algal control
PRIMARY
INFORMATION
NEEDS
» Physical sediment
features
» Chemical sediment
features
*Area to be treated
» Water depth
*Material to be used
for sealing
* Physical sediment
features
» Chemical sediment
features
*Area to be treated
» Water depth
* Chemical to be
applied/dose
* Sources of water
* Quality of source
water
* Target concentration
or detention time
* Flow necessary to
achieve dilution or
flushing rate
KEY
WATER ISSUES
* Interactions of
treatment with water
column
» Interactions of
treatment with water
column
* Variability in water
supply quantity or
quality
» Downstream flow
restrictions
KEY
SEDIMENT ISSUES
» Longevity of effects
* Longevity of effects
* Potential for
resuspension
KEY
BIOLOGICAL
ISSUES
» Impacts on benthic
organisms
* Facilitation of
colonization by new
organisms
* Impacts on biota of
water column
* Impacts on benthic
organisms
» Facilitation of
colonization by new
organisms
* Potential impacts on
biota of water column
» Possible washout of
zooplankton and fish
larvae
* Reduced fish
production with lower
nutrient base
* Importance of
attached algae in
lake
KEY
USE ISSUES
» Use restrictions to
protect barrier
* Safety concerns for
contact recreation in
barrier area
* Water use restrictions
during treatment
* Use restrictions to
minimize
resuspension/burial
of treated sediment
* Safety concerns
associated with
increased
inflow/outflow
* Possible use
impairment with poor
quality flushing source
water
KEY
COST FACTORS
* Cost of materials
*Cost of application
»Cost of maintenance
* Monitoring program
» Cost of chemicals
* Cost of application
»Monitoring program
»Cost of source water
*Costof any piping,
control structures,
and/or pumping
» Monitoring program
-------
K>
N>
Oi
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
8. Dredging
9. Dye addition
APPLICABLE USES
OF THE TECHNIQUE
* Increased
depth/access
* Alteration of bottom
composition
* Removal of nutrient
reserves
* Reduction in oxygen
demand
» Algal control
* Fe and Mn control
* Rooted plant control
» Habitat enhancement
» Reduced light
penetration
» Algal control
* Rooted plant control
PRIMARY
INFORMATION
NEEDS
» Existing and
proposed bathymetry
* Volume of material to
be removed
* Physical nature of
material to be
removed
* Chemical nature of
material to be
removed
* Nature of underlying
material to be
exposed
* Protected resource
areas
»Dewatering capacity
of sediments
* Provisions for
controlling water level
* Equipment access
» Pipeline route
* Potential disposal sites
* Dredging
methodology
restrictions
* Water depth and
volume to be treated
» Flushing rate
»Thermal regime
KEY
WATER ISSUES
» Possible peak flows
» Expected mean flows
» Downstream flow
needs
*Turbidity
generation/control
» Possible contaminants
in discharge from
containment area
* Increased surface
temperature due to
light absorption by
dye
* Possible stratification
of shallow water
» Downstream transport
of dye
KEY
SEDIMENT ISSUES
» Classification of
dredged material for
disposal purposes
* Physical handling
limitations
» Drying time
» Bulking factor
* Possible uses of
dredged material
* Adsorption of dye
and reduced longevity
of effects
KEY
BIOLOGICAL
ISSUES
* Preservation vs.
restoration vs.
restructuring of biotic
communities
* Presence of any
protected species
» Possible impacts on
wetlands
» Other habitats of
special concern
* Potential for plants to
impede dredging
* Ecological impact of
reduced light and
increased surface
temperature
KEY
USE ISSUES
* Possible loss of water
supply and
recreational use
during project
* Potential short- and
long-term habitat
impacts
»Access and safety
concerns
» Interference with use
as a potable supply
* Acceptability of water
coloration
KEY
COST FACTORS
» Engineering and
permitting costs
* Construction of
containment area
» Equipment purchases
» Operational costs
» Contract dredging
costs
* Ultimate disposal
costs
»Containment area
restoration
* Possible sale of
dredged material
» Monitoring program
*Cost of dye
*Cost of application
*Monitoring program
-------
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
1 0. Hydroraking
or rotovation
1 1 . Harvesting,
pulling, or
cutting
12. Nutrient
inactivation
APPLICABLE USES
OF THE TECHNIQUE
* Rooted plant control
* Removal of physical
obstructions (stumps,
root masses)
* Rooted plant control
» Dense algal mat
control
* Reduced phosphorus
levels/algal control
PRIMARY
INFORMATION
NEEDS
* Characterization of
plant assemblage
»Area to be treated
» Sediment features
» Water depth
* Potential disposal
areas
» Characterization of
plant assemblage
*Area to be treated
» Water depth
* Physical obstructions
* Potential disposal
areas
* Phosphorus
concentration and
forms
* Water volume to be
treated
*Alkalinity and pH of
water
* Expected reaction
efficiency
* Flushing rate
»:Phosphorus load to ,-
lake from external
and internal sources
KEY
WATER ISSUES
* Increased turbidity
» Water chemistry
impacts of interaction
with sediments
* Potential for increased
turbidity and floating
plant fragments
* Flushing rate
variability
^Circulation pattern
* Stability of alkalinity
and pH
KEY
SEDIMENT ISSUES
* Post-treatment sedi-
ment resuspension
susceptibility
* Sediment-water
interactions
* Post-treatment
sediment resuspension
susceptibility
» Sediment-water
interactions
* Interaction with settled
floe
» Potential for reduced
sediment release of
phosphorus
KEY
BIOLOGICAL
ISSUES
* Recolonization of
exposed sediment
surfaces
» Impacts to benthic
organisms
* Regrowth of plants
» Recolonization of
exposed sediment
surfaces
* Impact on organisms
associated with plants
* Potential to spread
plant species by frag-
mentation and drift
»Toxicity through
aluminum or pH
effects
* Impact on benthic
organisms and
zooplankton
* Possible reduced fish
production with
reduced fertility
KEY
USE ISSUES
*Treatment effects on
water supply quality
»Use restrictions during
treatment
* Safety concerns
during harvesting
* Possible use
restrictions
during/after treatment
» Restrictions to
minimize
resuspension of floe
KEY
COST FACTORS
* Cost of equipment
and labor, usually as
contracted project
» Monitoring program
»Cost of equipment
and labor
» Contract vs. local staff
vs. volunteer
approach
» Disposal location and
restrictions
» Monitoring program
* Cost of chemical
»Need for buffering
*Cost of application
* Monitoring program
-------
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
13. Nutrient
supplementa-
tion
14. Other
chemical
treatments
15. Pollutant
capture
(basins within
a lake)
1 6. Rules and
regulations
APPLICABLE USES
OF THE TECHNIQUE
» Enhanced fish
production
* Control of algal
composition
»Particulate
settling/algal control
* Nuisance fauna
control
*pH adjustment
» Oxidation/disin-
fection
» Reduction in nutrient
levels/algal control
« Reduced loading of
multiple pollutants
* User conflict
resolution
*Minimization of
pollutant loading
» Minimization of
nuisance species
introductions
PRIMARY
INFORMATION
NEEDS
* Detailed water
chemistry
» Loads of major
nutrients
* Flushing rate
» Algal assemblage
features
» Detailed water
chemistry
* Flushing rate
»Algal assemblage
features
* Target load reduction
* Physical limits on
detention
* Treatment processes
needed to achieve
target reduction
* Inflow rate
* Inflow quality
* Potential threats and
control needs
»User population
demographics
* Modeled or predicted
results of control
strategy
KEY
WATER ISSUES
» Possible water quality
effects of additions
» Possible water qualify
effects of additions
* Effect on pollutant
release by sediments
»Variability in flow and
quality of incoming
water
» Flooding adjacent to
detention areas
» Potential for
unanticipated impacts
KEY
SEDIMENT ISSUES
» Possible increase in
sediment accumula-
tion rate
» Possible increase in
sediment
accumulation rate
* Need for removal of
accumulated sediment
from detention area
» Potential for
unanticipated impacts
KEY
BIOLOGICAL
ISSUES
* Changes in food web
structure
» Potential for shifts in
algal species to
undesirable forms
» Impacts on specific
biota or community as
a whole
» Habitat value of
newly created
detention area(s)
» Loss of open,
contiguous water area
through partitioning
* Potential for
unanticipated impacts
KEY
USE ISSUES
» Potential for increased
water supply
treatment needs
»Use impairment by
decreased
transparency
* Use restrictions
associated with
treatment
*Access and safety
concerns
* Altered use patterns
and user satisfaction
KEY
COST FACTORS
» Cost of chemical
»Cost of application
* Monitoring program
*Cost of chemical
»Cost of application
* Monitoring program
»Cost of engineering
design
»Cost of materials and
construction
* Maintenance costs
» Monitoring program
» Cost of rule
development
»Cost of enforcement
-------
KS
K>
00
Table 7-3.— Factors in selecting management techniques (continued).
TECHNIQUE
17. Selective
withdrawal
1 8. Water level
control
APPLICABLE USES
OF THE TECHNIQUE
» Discharge of poor
quality water and
possible algal control
* Prevention of
hypolimnetic
anoxia/algal control
» Intake of best quality
water
» Access to structures
for maintenance or
construction
»Access to sediments
for removal
(dredging)
* Flood control
* Prevention of ice
damage to shoreline
and structures
* Sediment compaction
» Rooted plant control
*Fish reclamation
» Flushing
PRIMARY
INFORMATION
NEEDS
*Vertical variation in
water quality
* Depth and volume of
epilimnion and
hypolimnion
* Inflow rate/flushing
rate
* Hypolimnetic/sediment
oxygen demand
* Downstream
constraints
*Target level of water
»Pond bathymetry
»Area to be
exposed/flooded
*Maximum/minimum
volume
* Timing and frequency
of
drawdown/flooding
* Outlet control features
*Climatological data
* Normal range of
outflow
*Outflow during
drawdown and refill
*Time to draw down or
refill
KEY
WATER ISSUES
» Potential for
withdrawal to exceed
inflow and cause
drawdown
» Potential loss of
hypolimnion and
thermal stratification
* Water quality effects
. of removal of best
quality water
* Possible need to treat
discharge
* Flood storage
gained/lost
» Effects on peak flows
» Relative area and
volume of lake
remaining
* Effects on nutrient
levels
* Effects on oxygen
levels
* Effects on pH levels
KEY
SEDIMENT ISSUES
* Potential for
resuspension and
capture in
discharge/intake
» Potential for sloughing
» Potential for shoreline
erosion
» Potential for
dewatering and
compaction
» Potential for odors
» Access and safety
considerations
KEY
BIOLOGICAL
ISSUES
* Potential for
impingement or
entrapment of
organisms
» Impact on thermally
sensitive species
* Anticipated impacts to
target and non-target
plant species in lake
» Presence of protected
species
»Association of fauna
with areas to be
exposed
* Potential impacts to
connected wetlands
KEY
USE ISSUES
* Impairment of contact
recreation by
drawdown
* Impairment of fishing
success by thermal
alteration
* Use of lake water as
a supply
* Depth of any wells
within zone of
influence
» Alternative water
supplies
» Downstream flow
restrictions
* Emergency response
system
* Possible elimination of
usable open water
» Access and safely
* Potentially impaired
appearance during
drawdown
KEY
COST FACTORS
* Cost of pipe
installation
* Cost of control
structure
*Cost of any pumping
» Monitoring program
* Structural alteration to
facilitate control
* Pumping or
alternative water
moving technology
* Operational cost of
controlling outflow
* Alternative water
supply provision
* Monitoring program
-------
CHAPTER 7: Management Techniques Within the Lake or Reservoir
For any given technique, it is essential to know what it can and cannot do for
the lake; in other words, it must be evaluated ecologically. Once it's deter-
mined to be applicable, its side effects relating to water quantity and quality, sedi-
ment, and system biology must be considered. Perhaps most important are its
potential effects on non-target organisms, as these will affect permitting and pub-
lic perception of the project.
Side effects of techniques, expected or not, positive or negative, can
greatly influence practical aspects of implementation. Successful permitting and
funding of the program may depend on controlling impacts on non-target organ-
isms or public perception of risk.
The effects on water use must also be carefully considered. The chosen
technique should further the goals set for the use of the lake, but will it do so im-
mediately, or will there be a substantial lag time, possibly with use restrictions or
other negative impacts? It cannot be assumed that long-term benefits will justify
short-term impairment of uses in the public arena, although informed groups will
usually make some sacrifices.
Costs are almost always a critical consideration in lake management.
It has been said that "the most important elements in lake management are not
phosphorus and nitrogen, but silver and gold" (Canfield, 1992). Unfortunately,
many choices of techniques have been based on what was affordable at the mo-
ment, not on the long-term cost-benefit ratio.
While a technique that addresses the source of the problem usually costs
more at the outset, results should last. A management program that provides at
least 10 years of benefits at a high initial capital cost may not really be expensive
compared to a maintenance bargain that has to be repurchased many times over
a period of 10 years without ever solving the real problem. Costs should be com-
pared on at least a 10-year basis, preferably 20 years or even longer.
Capital, operational, contractor, and monitoring costs should all be consid-
ered in comparing management options — and they should be figured for the
long term. A single herbicide treatment that may control vegetation for a year
should not be compared with a dredging program that provides several decades
of control, increases water depth, and probably has other benefits. The herbicide
treatment may be more appropriate in some cases, but the cost of techniques
should be put on an equal scale of magnitude and longevity of benefits.
The relationship of problem and potential solution must also be evaluated in
ethical terms. Although ethical criteria are often less clear than ecological or
cost concerns, many of the evaluation points already discussed incorporate ethi-
cal judgments. Ethics deals with values and fairness, and though some will see this
as highly subjective, establishing management goals must be done in an ethical
manner. If society is to achieve balance and sustainability in its interactions with
the environment, ethical questions must be posed and answered.
Management Options
Many of the techniques for managing and improving lakes were developed years ago,
but only in the last two decades has the effectiveness of many of them been docu-
mented through applied research supported by the U.S. Environmental Protection
Agency's Clean Lakes Program, corresponding state programs, the National Science
Foundation, other governmental agencies, and private corporations. However, careful
documentation of results, longevity, and costs continues to be a major need.
c,
i, operational,
contractor, and
monitoring costs should
all be considered in
comparing manage-
ment options — and
they should be figured
for the long term.
229
-------
Managing Lakes and Reservoirs
I techniques that reduce
light and nutrients can
control algae.
Most techniques and products described in this manual are considered to be
effective in at least some circumstances; a few others are noted because of signifi-
cant media coverage or theoretical appeal.
The reader is encouraged to seek additional information and opinions (see,
for example, Cooke et al. I993a; McComas, 1993; NY State Dep. Environ. Conserv.
and NY Fed. Lake Assns. 1990), and to critically evaluate each option within the
context of the target lake.
Lake managers should ask for scientific documentation regarding a procedure,
product, or technique, especially one not described here. Discuss techniques with a
lake restoration expert not financially involved in its sale or installation. Too many
lake associations have spent thousands of dollars on products and procedures that
don't work or are inappropriate to the problem or lake.
Funds are well spent to properly evaluate techniques with specific reference
to your lake. Few lake management programs are truly inexpensive, and a proper
diagnostic/feasibility assessment can save far more money than it costs.
Nuisance Algae
Excessive algal growth can become a serious nuisance in lakes. Two growth forms
are most troublesome:
• Free-floating microscopic cells, colonies, or filaments — called
phytoplankton — that discolor the water and sometimes form green
scum on the surface. Although these algae come from a variety of algal
groups, including blue-greens, greens, diatoms, goldens, euglenoids, and
dinoflagellates, the blue-greens tend to cause the most problems
because of their high density (blooms), taste, odor, and possible
toxicity.
• Mats of filamentous algae associated with sediments and weed beds,
but that often float to the surface once they reach a certain density.
These are most often green algae of the orders Cladophorales or
Zygnematales, or blue-green algae (more properly cyanobacteria) of
the order Oscillatoriales.
Algae reproduce mainly through cell division, although resting cysts help
them survive unfavorable periods. When growth conditions are ideal (warm,
lighted, nutrient-rich), algae multiply rapidly and create massive blooms within a
few weeks. Many algal blooms produce taste and odor problems, and their decay
may decrease oxygen.
Many water treatment problems stem from algae in the water supply reser-
voir:
• Poor taste and odor are often associated with algal blooms and mats.
• Some common bloom-forming blue-green algae produce toxins that
may kill domestic animals and be linked to certain illnesses in humans.
• The combination of algal organic matter and chlorine disinfectant can
form potential carcinogenic byproducts such as trihalomethanes.
230
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
How to Control Algae
Algae need light and nutrients to grow. Turbidity, shading by plants, or massive
algal growth itself can reduce the light; or, an essential nutrient, usually phospho-
rus, can be limited. Techniques (Table 7-4) such as dyes, artificial circulation, and
selective plantings seek to limit light, whereas aeration, dilution and flushing,
drawdown, dredging, phosphorus inactivation, and selective withdrawal are used
to reduce nutrients.
Adding nutrients selectively may provide an ecologically complex solution in
some cases. Altering the ratio of nutrients may encourage the growth of algae
that are more amenable to other control techniques, like grazing and settling. Al-
though theoretically sound (Tilman, 1982), this approach has rarely been used in
practical lake management.
Settling, consumption by grazers, and cellular death control algae naturally.
Natural processes can be accelerated by using such techniques as settling agents,
biomanipulation (either encouraging grazing or adding bacteria or viruses to kill
algal cells), algaecides, and mechanical removal. Unfortunately, algae are remark-
ably adaptable, and none of these techniques works on all algal communities.
• Many blue-greens are buoyant and resist settling.
• Nuisance green algae (Chlorococcales and Cladophorales) and certain
blue-green algae (especially Aphanizomenon) are often resistant to
copper, the most common algaecide, and also resist grazers.
9 Only very dense algal mats can be harvested, and then with difficulty.
Filamentous algal mats are difficult to control. They usually form at the sedi-
ment-water interface or in rooted plant beds, nourished by nutrients released by
decay processes in the presence of adequate light. As mat density increases,
photosynthetic gases are often trapped, and the mat may float upward and ex-
pand. Neither grazing, settling, nor algaecides has much effect, and harvesting is
usually not practical. The best control is to prevent mats from forming by remov-
ing sediment or treating the algae at an early stage (phosphorus inactivation or
early algaecide application).
Aeration or Oxygenation
Aeration puts air into the lake, increasing the concentration of oxygen by trans-
ferring it from gas to liquid and generating a controlled mixing force. Using pure
oxygen maximizes the transfer. In this chapter, we deal with aeration as a tech-
nique intended to add oxygen to deep lakes without disrupting stratification.
Aeration is most appropriately used to prevent hypolimnetic anoxia (low oxy-
gen in the bottom layer) so that when the lake stratifies (separates into layers),
minimal phosphorus, iron, manganese, and sulfides will be released from sediments.
Aeration also retards the buildup of undecomposed organic matter and
compounds (e.g., ammonium) near the bottom of the lake, and can increase the
amount of water available to zooplankton and fish living in the lower, colder wa-
ters.
Permits are generally required for aeration projects, but hypolimnetic aera-
tion is among the easier lake management processes to get approved, having few
adverse side effects.
231
-------
Managing Lakes and Reservoirs
Table 7-4.— Management options for control of algae.
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS . -' ; ." .' : :-':~ •':':^:^i:''];'':^: '/: ,^\.J.: .'.'.; .•'..-' ;.' V^
1 . Hypolimnetic
aeration or
oxygenation
2. Circulation and
destratification
3. Dilution and
flushing
4. Drawdown
* Addition of air or oxygen at
varying depth provides oxic
conditions
*May maintain or break
stratification
*Can also withdraw water,
oxygenate, then replace
* Use of water or air to keep water
in motion
* Intended to prevent or break
stratification
*GeneralIy driven by mechanical
or pneumatic force
* Addition of water of better
quality can dilute nutrients
* Addition of water of similar or
poorer quality flushes system to
minimize algal buildup
*May have continuous or periodic
additions
» Lowering of water allows
oxidation, desiccation, and
compaction of sediments
* Duration of exposure and degree
of dewatering of exposed areas
are important
*Algae are affected mainly by
reduction in available nutrients
*Oxic conditions promote
binding/sedimentation of
phosphorus
* Counteraction of anoxia
improves habitat for
fish/invertebrates
» Buildup of dissolved iron,
manganese, ammonia, and
phosphorus reduced
* Reduces surface buildup of algal
scums; promotes uniform
appearance
*May disrupt growth of some
algae
* Counteraction of anoxia
improves habitat for
fish/invertebrates
»Can eliminate local problems
without obvious impact on whole
lake
» Dilution reduces nutrient
concentrations without altering
load
* Flushing minimizes detention;
response to pollutants may be
reduced
*May reduce available nutrients or
nutrient ratios, affecting algal
biomass and composition
» Opportunity for shoreline
cleanup/structure repair
* Flood control utility
*May provide rooted plant control
as well
*May disrupt thermal layers
important to fish community
*May promote supersaturation
with gases harmful to fish
* Permits usually required
»May spread local impacts
*May increase oxygen demand at
greater depths
»May promote downstream
impacts
» Diverts water from other uses
* Flushing may wash desirable
zooplankton from lake
» Use of poorer qualify water
increases pollutant loads
* Possible downstream impacts
* Possible impacts on contiguous
emergent wetlands
* Possible effects on overwintering
reptiles or amphibians
* Possible impairment of well
production
* Reduction in potential water
supply and fire fighting capacity
»Alteration of downstream flows
* Possible overwinter water level
variation
*May result in greater nutrient
availability if flushing inadequate
232
-------
CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS „ L.,,.^,1
5. Dredging
5. a. "Dry" excavation
5.b."Wet" excavation
5.c. Hydraulic removal
* Sediment is physically removed
by wet or dry excavation, with
deposition in a containment area
for dewatering
* Dredging can be applied on a
limited basis, but is most often a
major restructuring of a severely
impacted system
* Nutrient reserves are removed
and algal growth can be limited
by nutrient availability
Hake drained or lowered to
maximum extent practical
» Target material dried to maximum
extent possible
» Conventional excavation
equipment used to remove
sediments
*Lake level may be lowered, but
sediments not substantially
exposed
* Draglines, bucket dredges, or
long-reach backhoes used to
remove sediment
» Lake level not reduced
» Suction or cutterhead dredges
create slurry which is
hydraulically pumped to
containment area
* Slurry is dewatered; sediment
retained, water discharged. May
involve polymer-aided settling or
vacuum-aided dewatering.
»Can control algae if internal
recycling is main nutrient source
» Increases water depth
*Can reduce pollutant reserves
*Can reduce sediment oxygen
demand
*Can improve spawning habitat
for many fish species
*Allows complete renovation of
aquatic ecosystem
»Tends to facilitate a very thorough
effort
*May allow drying of sediments
prior to removal
* Allows use of less specialized
equipment
* Requires least preparation time or
effort, tends to be least costly
dredging approach
»May allow use of easily acquired
equipment
»May preserve aquatic biota
* Creates minimal turbidity and
impact on most biota
*Can allow some lake uses during
dredging
*Allows removal with limited
access or shoreline disturbance
» Temporarily removes benthic
invertebrates
*May create turbidity
*May eliminate fish community
(complete dry dredging only)
»May be impacts from
containment area discharge
*May be impacts from dredged
material disposal
»Mqy interfere with recreation or
other uses during dredging
^Eliminates most aquatic biota
unless a portion left undrained
^Eliminates lake use during
dredging
» Usually creates extreme turbidity
» Tends to result in sediment
deposition in surrounding area
* Normally requires intermediate
containment area to dry
sediments prior to hauling
*May cause severe disruption of
ecological function
* Usually eliminates most lake uses
during dredging
» Often leaves some sediment
behind
»Cannot handle coarse or
debris-laden materials
* Requires sophisticated and more
expensive containment area
* Requires overflow discharge from
containment area
233
-------
Managing Lakes and Reservoirs
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS !
6. Light-limiting
dyes and surface
covers
6.a. Dyes
6.b. Surface covers
7. Mechanical
removal
8. Selective
withdrawal
* Creates light limitation
* Water-soluble dye is mixed with
lake water, thereby limiting light
penetration and inhibiting algal
growth
»Dyes remain in solution until
washed out of system
*Opaque sheet material applied
to water surface
* Filters pumped water for water
supply purposes
*Collection of floating scums or
mats with harvesters, booms,
nets, or other devices
» Continuous or multiple
applications per year usually
needed
* Discharge of bottom water which
may contain (or be susceptible to)
low oxygen and higher nutrient
levels
* Intake of water from low algae
layer to maximize supply quality
»May be pumped or utilize
passive head differential
* Creates light limit on algal
growth without high turbidity or
great depth
*May achieve some control of
rooted plants as well
* Produces appealing color
»Creates illusion of greater depth
* Minimizes atmospheric and
wildlife pollutant inputs
* Algae and associated nutrients
can be removed from system
» Surface collection can apply on
an "as needed" basis
*May remove floating debris
» Collected algae dry to minimal
volume
* Removes targeted water from
lake efficiently
* Complements other techniques
such as drawdown or aeration
»May prevent anoxia and
phosphorus buildup in bottom
water
»May remove initial phase of algal
blooms which start in deep water
*May create coldwater conditions
downstream
*May cause thermal stratification
in shallow ponds
*May facilitate anoxia at sediment
interface with water
»May not control surface
bloom-forming species
»May not control growth of
shallow water algal mats
» Minimizes atmospheric gas
exchange
* Limits recreational use
» Filtration requires high backwash
and sludge handling capability
for use with high algal densities
» Labor intensive unless a
mechanized system applied, in
which case it is capital intensive
*Many algal forms not amenable
to collection by net or boom
»May impact non-targeted
aquatic life
»May result in poor water quality
downstream if not treated
*May eliminate colder thermal
layer important to certain fish
»May promote mixing of some
remaining poor quality bottom
wafer with surface waters
»May cause unintended
drawdown if inflows do not
match withdrawal
234
-------
CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
CHEMICAL CONTROLS
9. Algaecides
9. a. Forms of copper
9.b. Forms of
endothall
(7-oxabicyc!o[2.2.1]
heptane-2,3-
dicarboxylic acid)
9. c. Forms of diquat
(6,7-dihydropyrido
[l,2-2',r-c]
pyrazinediium
dibromide)
* Liquid or pallatized algaecides
applied to target area
*Algae killed by direct toxicity or
metabolic interference
* Typically requires application at
least once/yr, often more
frequently
» Contact algaecide
* Cellular toxicant, suggested
disruption of photosynthesis,
nitrogen metabolism, and
membrane transport
» Applied as wide variety of liquid
or granular formulations, often in
conjunction with chelators,
polymers, surfactants, or
herbicides
» Contact algaecide
* Membrane-active chemical which
inhibits protein synthesis
» Causes structural deterioration
* Applied as liquid or granules,
usually as hydrothol formulation
for algae control
* Contact algaecide
* Absorbed directly by cells
» Strong oxidant; disrupts most
cellular functions
* Applied as a liquid, sometimes in
conjunction with copper
» Rapidly eliminates algae from
water column, normally with
increased water clarity
»May result in net movement of
nutrients to bottom of lake
» Effectively and rapidly controls
many algal species
* Approved for use in most water
supplies
* Moderate control of thick algal
mats; used where copper is
ineffective
«• Limited toxicity to fish at
recommended dosages
>Acts rapidly
•^Moderate control of thick algal
mats; used where copper alone is
ineffective
» Limited toxicity to fish at
recommended dosages
»Acts rapidly
»May be toxic to non-target areas
or species of plants/animals
»May restrict water use for varying
time after treatment
» Increased oxygen demand and
possible toxicity may result from
decaying algae
» Nutrients may recycle, allowing
other growths
* Toxic to aquatic fauna as a
function of concentration,
formulation, temperature, pH,
and ambient water chemistry
* Less effective at colder
temperatures or at high inorganic
solids levels
* Copper ion persistent;
accumulates in sediments or
moves downstream
* Certain green and blue-green
nuisance species are resistant to
copper
»Lysing of cells releases cellular
contents (including nutrients and
toxins) into water column
* Non-selective in treated area
» Toxic to aquatic fauna (varying
degrees by formulation)
*Time delays on use for water
supply, agriculture, and recreation
* Non-selective in treated area
» Toxic to some zooplankton at
recommended dosage
» Inactivated by suspended
particles; ineffective in muddy
waters
»Time delays on use for water
supply, agriculture, and recreation
235
-------
Managing Lakes and Reservoirs
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
ICHEMICAL CONTROLS "' " " " "" '•"^ " ^-^^^ •-•^••^•:^ -,;';:-^*:
"*'" ' ll" ll'l ' ', I,, h'' ' h, ' ,!!'", »i, ' ,L|I«' , , , •",; ..,."(S-'FliE ->-f I. <-?• f ''• • , -f .' . -'• \ 1 • :, ! -i '.JtO-' - • ' ' /'I" •. . ' , -"'L ' ' ...,,„/•]
1 0. Phosphorus
inactivation
1 1 . Sediment
oxidation
1 2. Settling agents
13. Selective nutrient
addition
* Typically salts of aluminum, iron,
or calcium are added to the lake,
as liquid or powder
* Phosphorus in the treated water
column is complexed and settled
to the bottom of the lake
* Phosphorus in upper sediment
layer is complexed, reducing
release from sediment
* Permanence of binding varies by
binder in relation to redox
potential and pH
* Potential for use on inlet streams
as well
* Addition of oxidants, binders,
and pH adjusters oxidizes
sediment
* Binding of phosphorus is
enhanced
*Denitrification may be stimulated
* Closely aligned with phosphorus
inactivation, but can be used to
reduce algae directly, too
*lime, alum, or polymers applied,
usually as a liquid or slurry
*Creates a floe with algae and
other suspended particles
* Floe settles to bottom of lake
* Re-application necessary if algal
growth not controlled
» Ratio of nutrients changed by
additions of selected nutrients
* Addition of non-limiting nutrients
can change composition of algal
community
* Processes such as settling and
E razing can then reduce algal
iomass (productivity can
actually increase, but standing
crop can decline)
*Can provide rapid, major
decrease in phosphorus
concentration in water column
»Can minimize release of
phosphorus from sediment
*May remove other nutrients and
contaminants as well as
phosphorus
* Flexible with regard to depth of
application and speed of
improvement
*Can reduce phosphorus supply to
algae
*Can alter N:P ratios in water
column
»May decrease sediment oxygen
demand
* Removes algae and increases
water clarify without lysing most
cells
* Reduces nutrient recycling if floe
sufficient
* Removes non-algal particles as
well as algae
*May reduce dissolved
phosphorus levels at the same
time
»Can reduce algal levels where
control of limiting nutrient not
feasible
»Can promote non-nuisance forms
of algae
*Can improve productivity of
system without increasing
standing crop of algae
*May be toxic to fish and
invertebrates, especially by
aluminum at low pH
* Phosphorus may be released
under anoxia or extreme pH
*May cause fluctuations in water
chemistry, especially pH, during
treatment
*Floc may be resuspended in
shallow areas with extreme
turbulence
»Adds to bottom sediment, but
typically an insignificant amount
»May affect benthic biota
* Longevity of effects not well
known
»May affect aquatic fauna
* Water chemistry may fluctuate
during treatment
*Floc may resuspend in shallow,
well-mixed waters
* Promotes increased sediment
accumulation
*May result in greater algal
abundance through uncertain
biological response
*May require frequent application
to maintain desired ratios
*May have downstream effects
236
-------
CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-4— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
CHEMICAL (CONTROLS
1 4. Management for
nutrient input
reduction
* Generally not an in-lake process
(see Chapter 6), but essential to
note in any algal control program
* Includes wide range of watershed
and lake edge activities intended
to eliminate nutrient sources or
reduce delivery to lake
»Can involve use of wetland
treatment cells or detention areas
created from part of lake
* Essential component of algal
control strategy where internal
recycling is not the dominant
nutrient source, and desired even
where internal recycling is
important
*Acts against the original source of
algal nutrition
* Decreases effective loading of
nutrients to lake
»Creates sustainable limitation on
algal growth
*May control delivery of other
unwanted pollutants to lake
* Generally most cost effective over
long term
* Facilitates ecosystem
management approach which
considers more than just algal
control
*May involve considerable lag
time before improvement
observed
»May not be sufficient to achieve
goals without some form of
in-lake management
* Reduction of overall system
fertility may impact fisheries
»May cause shift in nutrient ratios
that favor less desirable species
»May cost more in the short term,
as source management is
generally more involved than one
or a few treatments of symptoms
of eutrophication
BIOLOGICAL CONTROLS _
15. Enhanced grazing
1 5. a. Herbivorous fish
15.b. Herbivorous
zooplankton
»Manipulation of biological
components of system to achieve
grazing control over algae
» Typically involves alteration of fish
community to promote growth of
large herbivorous zooplankton, or
stocking with phytophagous fish
* Stocking of fish that eat algae
* Reduces planktivorous fish to
promote grazing pressure by
zooplankton
*May involve stocking piscivores
or removing planktivores
»May also involve stocking
zooplankton or establishing
refugia
*May increase water clarity by
changes in algal biomass or cell
size distribution without reduction
of nutrient levels
*Can convert unwanted biomass
into desirable form (fish)
* Harnesses natural processes to
produce desired conditions
* Converts algae directly into
potentially harvestable fish
» Grazing pressure can be adjusted
through stocking rate
* Converts algae indirectly into
harvestable fish
» Zooplankton community response
to increasing algae can be rapid
»May be accomplished without
introduction of non-native species
* Generally compatible with most
fishery management goals
»May involve introduction of
species
» Effects may not be controllable or
lasting
*May foster shifts in algal
composition to even less
desirable forms
»Typically requires introduction of
non-native species
* Difficult to control over long term
* Smaller algal forms may benefit
and bloom
» Highly variable response
expected; temporal and spatial
variability may be problematic
» Requires careful monitoring and
management action on 1 -5 yr
basis
»May involve non-native species
introduction(s)
* Larger or toxic algal forms may
benefit and bloom
237
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Managing Lakes and Reservoirs
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
BIOLOGICAL CONTROLS " . " : ••••--•-- '- ;•;. • •. -••--v».— -^::;; ;-r.-./":Vv .:;
1 6. Bottom-feeding
fish removal
1 7. Fungal/bacterial/
viral pathogens
1 8. Competition and
allelopathy
1 8.a. Plantings for
nutrient control
18.b. Plantings for
light control
* Removes fish that browse among
bottom deposits, releasing
nutrients to the water column by
physical agitation and excretion
*Addition of inoculum to initiate
attack on algal cells
» Plants may tie up sufficient
nutrients to limit algal growth
* Plants may create a light
limitation on algal growth
*ChemicaI inhibition of algae may
occur through substances
released by other organisms
* Plant growths of sufficient density
may limit algal access to nutrients
* Plants can exude allelopathic
substances that inhibit algal
growth
* Plant species with floating leaves
can shade out many algal
growths at elevated densities
* Reduces turbidity and nutrient
additions from this source
»May restructure fish community in
more desirable manner
*May create lakewide "epidemic"
and reduction of algal biomass
*May provide sustained control for
several years
»Can be highly specific to algal
group or genera
* Harnesses power of natural
biological interactions
*May provide responsive and
prolonged control
* Shift to rooted plant dominance
can improve habitat
* Productivity and associated
habitat value can remain high
without algal blooms
* Portable plant "pods," floating
islands, or other structures can be
managed to limit interference with
recreation and provide habitat
* Wetland cells in or adjacent to
the lake can minimize nutrient
inputs
* Vascular plants can be more
easily harvested than most algae
*Many floating species provide
valuable waterfowl food
* Targeted fish species are difficult
to eradicate or control
* Reduction in fish populations
valued by some lake users
(human and non-human)
* Largely experimental approach at
this time
* Results are uncertain
*May promote resistant forms with
high nuisance potential
*May cause high oxygen demand
or release of toxins by lysed algal
cells
* Effects on non-target organisms
uncertain
»Some algal forms appear
resistant
»Use of plants may lead to
problems with vascular plants
*Use of plant material may
depress oxygen levels
* Vascular plants may achieve
nuisance densities
*There will be a water depth
limitation on rooted plants but not
algae
* Vascular plant senescence may
release nutrients and cause algal
blooms
*The switch from algae to vascular
plant domination of a lake may
cause unexpected or undesirable
changes in lake ecology,
especially energy flow
*At the necessary density, the
floating plants will be a
recreational nuisance
*Low surface mixing and
atmospheric contact promote
anoxia near the sediment
238
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-4.— Management options for control of algae (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
BIOLOGICAL CONTROLS ' '
1 8. c. Addition of
barley straw
* Input of barely straw can set off a
series of chemical reactions that
limit algal growth
» Release of allelopathic chemicals
can kill algae
* Release of humic substances can
bind phosphorus
* Materials and application are
relatively inexpensive
* Decline in algal abundance is
more gradual than with
algaecides, limiting oxygen
demand and the release of cell
contents
* Success appears linked to
uncertain and potentially
uncontrollable water chemistry
factors
*May depress oxygen levels
» Water chemistry may be altered
in other ways unsuitable for
non-target organisms
»Some forms of algae may be
resistant and could benefit from
the treatment
How Aeration Works. Many methods can aerate a lake (see Fig.
7-1), but only a few maintain stratification:
• A full lift approach, usually driven pneumatically by compressed
air, moves hypolimnetic water to the surface, aerates it, and
replaces it in the hypolimnion. Return flow to the hypolimnion is
generally directed through a pipe to maintain separation of the
newly aerated waters from the surrounding epilimnion. To
provide adequate aeration, the hypolimnetic volume should be
pumped and oxygenated at least once every 60 days, preferably
more frequently.
• The partial lift system pumps air into a submerged chamber in
which oxygen is exchanged with the deeper waters (Fig. 7-1). A
housed compressor must be located on the shore, but the
aeration unit itself is submerged and does not interfere with lake
use or aesthetics.
• Layer aeration (Kortmann et al. 1994; Fig. 7-1) combines water
from different, carefully chosen temperature (and thus density)
regimes to form stable oxygenated layers anywhere from the
upper metalimnetic boundary down to the bottom of the lake.
Each layer retards the passage of phosphorus, reduced metals, and
related contaminants from the layer below. Either part of or the
whole hypolimnion may be aerated to the desired oxygen level
(water supply may demand less oxygen than a trout refuge, for
example).
Any of these three aeration systems can markedly improve lake con-
ditions, but experience has demonstrated that effects are neither uniform
nor consistent in aquatic systems:
• Zones of minimal interaction will often occur, possibly resulting in
localized anoxia and phosphorus release.
oration puts air into
the lake, increasing the '
concentration of oxygen
by transferring it from
gas to liquid and
generating a controlled
mixing force. •
239
-------
THERMO-
~ CLINE
BOTTOM
SEDIMEN7
Diffusion
Aeration
(Destratifying)
Full Lift
Aeration
Partial Lift
Aeration
Layer
Aeration
(Non-destratifying)
Down or Up draft
Circulation
(Impact on stratification
varies)
DIFFUSER (PNEUMATIC INPUT)
MECHANICAL PUMP
Figure 7-1.—Examples of aeration and circulation approaches.
• Partial lift systems may allow a band of anoxic water to persist
near the top of the metalimnion, allowing nutrient cycling and
supply to the epilimnion and discouraging vertical migration by
fish and zooplankton.
• Although extremely unlikely, supersaturation of nitrogen resulting
from aeration (not just oxygen is transferred if air is used) may
expose fish to "gas bubble disease."
The most critical information for designing an aeration system is the
amount of oxygen the lake must have. Oxygen demand is normally calcu-
lated from actual lake data. For stratified lakes, the hypolimnetic oxygen
demand can be calculated as the difference in oxygen levels between
the time layers formed in the lake and at some time during stratification
before levels decline below I mg/L.
Several factors complicate the assessment of oxygen demand, among
them the fact that oxygen consumption declines as oxygen supply declines.
Oligotrophic lakes may need less than 250 mg/m2/day, whereas eutrophic
lakes use at least twice that (Hutchinson, 1957), and 2,000 to 4,000
mg/m2/day have been measured in hypereutrophic lakes (Wagner, pers.
obs.) An experienced professional can help you with this calculation.
240
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
' Effects on Algae. Aeration controls algae by reducing phosphorus.
Two factors are important here: (I) Enough oxygen must be added to
meet the hypolimnetic demand, and (2) there must be an adequate supply
of substances that attract (bind) phosphorus (such as aluminum and iron
compounds), because aeration encourages binding to remove phosphorus
from the water.
Bound phosphorus does not necessarily become available after aera-
tion ceases, but the risk of release increases, especially where iron is the
dominant binder. Studies cited in Cooke et al. (I993a) show that without
enough permanent binders, available phosphorus tends to decline by one-
to two-thirds during aeration, but quickly rises to pre-aeration levels
when treatment ceases.
Circulation and Desfratification
Aeration is commonly used to mix shallow lakes (circulation), and sometimes to
destratify deep lakes.
^ Circulation mixes water to minimize stagnation in places such as coves
and can eliminate or prevent thermal stratification; both conditions stimu-
late algal blooms, decrease oxygen, and cause sediment to accumulate.
The circulatory process moves water — using surface aerators, bottom
diffusers, or water pumps — to create the desired circulation pattern in
shallow (usually <20 ft) lakes. Often, the effect is largely cosmetic; algae
are simply mixed more evenly in the water. However, the movement may
disrupt the life cycle of some algae, and limit their growth.
^ Stratification is broken or prevented in deeper lakes by injecting
compressed air into the water from a diffuser on the lake bottom or, in
some instances, moving the water with a wind-driven pump (Fig. 7-1). If it's
strong enough, the rising column of bubbles will mix the lake at a rate that
eliminates temperature differences between top and bottom waters. Us-
ing air as the mixing force also oxygenates the water somewhat.
^ Destratification may also control algae, usually through one or more
of these processes:
• Mixing to the lake bottom will increase an algal cell's time in
darkness, reducing the net photosynthesis and consequent algal
biomass.
• Introducing dissolved oxygen to the lake bottom may prevent
phosphorus release from sediments, curtailing this internal
nutrient source for algae.
• Rapid circulation, air-water contact, and the introduction of
carbon dioxide-rich bottom water during the initial mixing
period may cause a shift to less noxious green algae from
blue-greens.
• More zooplankters (which feed on algal cells) may survive
because they will be mixed throughout the water column, making
them less vulnerable to visually feeding fish.
Stratification: Distinct
layers of water in a lake,
separated according to
temperature:
• the warmest layer is
nearest the surface
(epliminion);
• the layer that resists
mixing, lies between the
top and bottom layers
(metalimnion);
• the coldest layer is at the
bottom (hypolimnion).
241
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Managing Lakes and Reservoirs
Results have varied greatly:
• Problems with low dissolved oxygen have usually been solved.
• When destratification is properly used in a water supply
reservoir, problems with iron and manganese can be eliminated.
• Where very small temperature differences from top to bottom
have been maintained all summer, algal blooms seem to decline.
• Phosphorus and turbidity have increased; in some cases
transparency has decreased.
• Surface scums have been prevented, although total algal biomass
may not be reduced.
• Systems that bring deep water to the surface can be inexpensive,
but unless enough water is moved to prevent anoxia near the
sediment-water interface, the quality of water brought to the
surface may cause deterioration of surface conditions.
• Systems that pump surface water to the bottom may improve
the oxygen level near the bottom, but may also cause unfavorable
circulation patterns and surface conditions.
Why do these mixing techniques sometimes fail? Either lake chemistry or
equipment may be responsible:
• A lake that receives high nutrient loads from its watershed is unlikely
to respond acceptably.
• If strongly stratified, a lake may be very difficult to destratify.
• Undersizing the mixing system is the major equipment-related cause
of failure for this technique. Lorenzen and Fast (1977) suggested that
an air flow of about 1.3 ft /min per acre of lake surface is required to
maintain mixing within the lake.
Many engineering details must be considered in designing a circulation sys-
tem, and the designer must understand the site conditions; once again, consult
with a professional to design your system.
Dilution and Flushing
Algae usually do not bloom in lake waters that have minimal nutrients, particularly
phosphorus. Concentrations in lake water reflect concentrations in incoming wa-
ter, the flushing rate or residence time of the lake, and the net amount that settles
onto sediments. While you should first try to reduce nutrients entering the lake,
you can dilute the concentration of nutrients within the lake by adding nutri-
ent-poor water.
When water low in phosphorus is added to the inflow, the actual phospho-
rus load will increase, but the mean phosphorus concentration should decrease.
Lakes with low initial flushing rates are poor candidates because in-lake concen-
tration could actually increase unless the dilution water is free of phosphorus
(Uttormark and Hutchins, 1980). Internal loading is another influential factor. You
must understand your lake's phosphorus budget to evaluate dilution as a poten-
tial algae control method.
Flushing can wash algae out of the lake faster than they can reproduce by
adding large amounts of water, whether or not it's low in nutrients. However,
242
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
complete flushing is virtually impossible in many lake systems; small, linear im-
poundments are the prime candidates for such treatment.
Although flushing washes out algal cells, their reproductive rate is so high
(blooms form within a few weeks), that only extremely high flushing rates will be
effective. A flushing rate of 10 to 15 percent of the lake volume per day is appro-
priate. Reliable water and nutrient budgets must be developed to evaluate flush-
ing as an algae control technique.
Very few documented case histories of dilution or flushing exist, in part be-
cause:
• Additional water is not often available, especially water that is low in
nutrients.
• Outlet structures and downstream channels must be able to handle
the additional discharge.
• Qualitative downstream impacts must be considered.
• Water used for dilution or flushing should be carefully monitored
prior to use in the lake.
Moses Lake in Washington state is one of the few recorded cases of suc-
cessful dilution (Welch and Patmont, 1980; Cooke et al. 1993a). Low-nutrient Co-
lumbia River water was diverted through the lake, achieving water exchange
rates of 10 to 20 percent per day. Algal blooms dramatically decreased, and trans-
parency significantly improved.
Drawdown
Lowering the water level and exposing sediments to oxidize and compact them will
decrease their oxygen demand and long-term phosphorus release rate. Recent re-
search (Mitchell and Baldwin, 1998) indicates that shifts in the bacterial community
during exposure may reduce phosphorus release after some drawdowns.
While the theory is attractive, in practice this approach suffers from several
important limitations:
• The most problematic sediments are in the deepest part of most
lakes, so the entire lake must be drained to achieve the maximum
result.
• It is difficult to dewater the sediments sufficiently to get more than
minor results.
• Nutrient release when the lake is refilled may actually increase until
the nutrients can be flushed from the system.
• To control drawdown, the lake must have a manageable outlet
structure and system hydrology normally associated only with
reservoirs.
For a number of reasons, using this technique to control algae appears un-
common and unreliable:
• Drawdown has little effect on algal resting cysts.
• Chemical and physical features of the sediments influence results of
drawdown.
• The effects of a drawdown are easily overwhelmed by high external
phosphorus inputs.
243
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Managing Lakes and Reservoirs
hen the upper
3.3 feet of extremely
nutrient-rich sediments
were removed from
Lake Trummen in
Sweden/ the total
hosphorus concentra-
!on in the lake dropped
harply and remained
irly stable for at least
8 years. Phytoplankton
!>roduction also declined.
,
Removing sediment from a lake can lower in-lake nutrient concentrations and
algal production by preventing the release of nutrients from the sediment.
Dredging also removes the accumulated resting cysts deposited by a variety of
algae. Although recolonization would probably be rapid, algal composition could
change. Even where incoming nutrient loads are high, dredging can reduce the
formation of benthic mats and related problems with filamentous green and
blue-green algae that depend on these substrates for nutrition.
A lake can be dredged by four methods:
• Dry excavation: the lake is drained as much as possible; sediments
are dewatered by gravity and/or pumping and removed with
conventional excavation equipment such as backhoes, bulldozers, or
draglines.
• Wet excavation: the lake is only partially drawn down (to minimize
downstream flows); wet sediments are excavated by amphibious
excavators or bucket dredges mounted on cranes.
• Hydraulic dredging: a substantial amount of water remains in the
lake to float the dredge and transport the sediment. Hydraulic dredges
are typically equipped with a cutterhead to loosen sediments that are
then mixed with water and pumped as a slurry of 80 to 90 percent
water (10 to 20 percent solids) through a pipeline extending from the
dredging site to a disposal area. Polymer addition and mechanical
dewatering can be used to improve handling of slurries.
• Pneumatic dredging: air pressure pumps sediments out of the lake
at a higher solids content (50 to 70 percent), much like hydraulic
dredging. This is a promising but fairly new technique that appears to
require less space and facilitates drying of the solids; however, few
dredges are operating in North America, and not enough experience
exists for a knowledgeable analysis.
Dry, wet, and hydraulic methods are illustrated in Figure 7-2, further out-
lined in Table 7-4, and discussed thoroughly in Cooke et al. (I993a).
Removing sediment can retard nutrient release, as illustrated by the follow-
ing examples:
• When the upper 3.3 feet of extremely nutrient-rich sediments were
removed from Lake Trummen in Sweden (Andersson, 1988), the total
phosphorus concentration in the lake dropped sharply and remained
fairly stable for at least 18 years. Phytoplankton production also
declined.
• Algae decreased and water clarity increased in Hills Pond in
Massachusetts after all soft sediment was removed and a stormwater
treatment wetland was installed in 1994 (Wagner, 1996).
• Dredging 6-acre Bulloughs Pond in Massachusetts in 1993 has
prevented thick green algal mats from forming for seven years now,
despite continued high nutrient levels in urban runoff (Wagner, pers.
obs.). These mats had previously begun as spring bottom growths,
then floated to the surface in midsummer.
244
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
"Leakproof" Dragline^
Truck
Bucket
Dredge
To
Containment
Wet" Dredging
Containment
Area
fe'r-L-j' .. .•..';'v.=-''-jji'.'»<-.'.J
Sediment
To
Containment
Sediment
Barge witr,
Containment
*-
To
Containment
Sediment
Hydraulic
Dredging
Figure 7-2.—Examples of dredging approaches.
While removing the entire nutrient-rich layer of sediment can control algae,
that goal is usually secondary; dredging is most frequently done to deepen a lake,
remove accumulations of toxic substances, or control macrophytes. The expense
of completely removing nutrient-rich sediment and the more pressing need for
watershed management are usually the primary reasons that dredging is not used
more often to control algae.
Dredging may also have serious negative effects on the lake and surrounding
area. Many of these problems are short-lived, and can be minimized with proper
planning. It should be kept in mind, however, that dredging represents a major re-
engineering of a lake, and should not be undertaken without clear recognition of
its full impact, positive and negative.
Among the most serious dredging problems is not having a large enough dis-
posal area to handle the volume of sediment and the turbid, nutrient-rich water
that accompanies it. Unless the sediment-water slurry from a hydraulic dredging
project can be retained long enough for it to settle, or it is treated prior to re-
lease, the nutrient-laden water will be discharged to a stream or lake. There, it
A,
trnong the most
serious dredging
problems is not having
a large enough disposal
area to handle the
volume of sediment
and the turbid,
nutrient-rich water that
accompanies it.
245
-------
Managing Lakes and Reservoirs
y\ properly conducted
dredging program
removes accumulated
sediment from a lake
and sets it back to the
time before sediment
• had collected.
.
may deplete oxygen and cause turbidity and algal blooms. These same problems
can also develop in the lake during the dredging operation, but they are usually
temporary.
Containment areas for dry dredging projects are less a concern than for hy-
draulic projects, with wet excavation providing intermediate risks. Recent ad-
vances in polymers and mechanical dewatering now allow a hydraulically dredged
slurry to be treated and loaded directly onto trucks. The cost of treatment may
be offset by lower containment area costs and less material handling.
Some dredging methods create considerable turbidity, and steps must be
taken to prevent the effects of contaminated sediments downstream.
Controlling inflow to the lake is another critical consideration, especially
during wet or dry excavation:
• For wet excavation projects, inflows must be routed around the lake,
as each increment of inflow must eventually be balanced by an equal
amount of outflow, and the in-lake waters may be very turbid.
• For dry excavation, water can often be routed through the lake in a
pipe or sequestered channel to prevent interaction with disturbed
sediments.
Before attempting to dredge, analyze the sediments for grain size, organic
content, nutrients, heavy metals, a wide variety of hydrocarbons, persistent pesti-
cides, and other toxic materials:
• The physical and chemical nature of the dredged material will
determine its potential uses; and
• Special precautions and disposal restrictions, some of them expensive,
will be required if sufficient quantities of regulated contaminants are
present.
Implementation and permit procedures (Chapter 8) are critical to the suc-
cess of a dredging project. Failed dredging projects are common, and failure can
almost always be traced to insufficient consideration of the many factors that
govern dredging success:
• No technique requires more up-front information about the lake and
its watershed.
• Many engineering principles are involved in planning a successful
dredging project, including sediment dewatering, bulking, and transport
mechanisms.
• No technique is more suitable for true lake restoration, but many
potential impacts must be considered and mitigated in the dredging
process.
A properly conducted dredging program removes accumulated sediment
from a lake and sets it back to the time before sediment had collected. A lake can
be partially dredged, but to control algae, it is far better to remove all nutri-
ent-rich sediment, as interaction between sediments and the water column in
one area can affect the entire lake.
Many benefits beyond algal control accrue from properly dredging a lake, in-
cluding a deeper lake, fewer rooted plants, and less sediment-water interaction.
Dredging can be very expensive, however; you should protect an investment in
dredging with an active watershed management program.
246
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CHAPTER 7: /Management Techniques Within the Lake or Reservoir
Light-limiting Dyes and Surface Covers
Dyes are sometimes lumped with algaecides as management options and are of-
ten subject to the same permit process as algaecides. But they act differently; dyes
reduce algae by inhibiting light penetration and resulting photosynthesis, so they
are more properly classified as a physical technique.
Typically blue, inert pigments, dyes produce a pronounced, generally aes-
thetic color in the water column. No direct toxic effects have been reported, and
organisms in the water do not absorb the color. Visibility declines in proportion
to the concentration of dye.
Dyes are more effective in deep water; growths in shallow waters are un-
likely to decline significantly. Dyes will not always eliminate floating scums or
mats, and may actually promote surface growths. Combined with a circulation
system, dyes can mask otherwise unpleasant algal blooms and improve the aes-
thetic appeal of ponds, reflecting pools, or similar water bodies.
Although the treatment must be repeated as the dye is flushed from the sys-
tem, treatments are relatively inexpensive. The greatest negative impact is that
limiting light penetration may cause thermal stratification in only 6 to 8 feet of
water; the sediment-water interface may then become anoxic, creating the po-
tential for a variety of impacts on water quality. In some cases, both aquatic vege-
tation and fish may be affected.
Surface covers are opaque sheets placed on the surface of a lake or reser-
voir to inhibit light penetration. This technique limits access on recreational lakes,
but has been used in reservoirs, especially for storage of "finished" water
(treated water ready for distribution). Aside from minimizing algal growth, such
covers support the Federal Safe Drinking Water Act by limiting interaction with
waterfowl and atmospheric deposition. Most covered storage reservoirs have
roofs, but plastic covers seem to perform acceptably on others.
Mechanical Removal
Mechanical sedimentation and filtration systems routinely remove algae in drink-
ing water treatment facilities, but such systems have not been developed for rec-
reational lakes. Treating enough lake water to reduce algal levels in a well-mixed
lake would be very difficult, as well as cost prohibitive, even for small lakes
(McComas, 1993).
Algal mats can be harvested with nets, booms, or commercial macrophyte
harvesters, but this can also be very expensive for an entire lake over the course
of a summer. Nets or a boom system may temporarily (though inefficiently) im-
prove small ponds. Mechanical harvesters must be properly designed to collect
algal mats; although seldom used, harvesters can gather surface mats on a small
scale. Since algae are mostly water, relatively little solid material is removed for
each unit of effort.
Selective Withdrawal
Selective withdrawal for water supply means locating the intake at the depth
where the water quality is most suited to the intended use. This requires stable
vertical water density layers, and is most often used with strongly stratified lakes.
247
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Managing Lakes and Reservoirs
To withdraw potable water from lakes, the choice is often between high al-
gae concentrations in the epilimnion and high iron and/or manganese in the hy-
polimnion. Intakes located near the thermocline (their interface) sometimes get
both high algae and high metals.
A choice of intake depths is preferred, allowing the intake depth to be ad-
justed according to the best available water quality. For cooling water, cold hypo-
limnetic withdrawal is preferred, as long as it does not contain high levels of
corrosive sulfides.
In managing recreational lakes, selective withdrawal is usually intended to re-
move the poorest quality water from the lake (normally at the bottom of the
lake), discharging it at a rate that prevents anoxia near the sediment-water inter-
face; this improves both lake conditions and discharge quality. This works in im-
poundments with small hypolimnia and/or large inflows, but for most lakes, the
water withdrawn must be treated before discharge.
Where phosphorus has accumulated in the hypolimnion, selective discharge
of hypolimnetic waters before fall turnover can reduce phosphorus. But, unless
summer inflows are substantial, this may lower the lake level considerably. Selec-
tive discharge can increase the benefit of a drawdown, however, even if an outlet
structure has to be retrofit; the one-time capital cost confers permanent control
with minimal operation and maintenance costs.
Hypolimnetic withdrawal can reduce epilimnetic phosphorus concentra-
tions; Niirnberg (1987) found this to be true in 17 lakes following I to 10 years of
hypolimnetic withdrawal. To succeed, however, a withdrawal program must ad-
dress the possible effects of summer drawdown, disruption of stratification, and
effects on downstream water quality.
In some large western reservoirs, hypolimnetic discharges are a major out-
flow and actually maintain downstream coldwater fisheries. Discharged water
may have to be aerated or otherwise treated, but it does remove phosphorus
and other contaminants from the lake.
Algaecides
Algaecides kill algae in the lake. The oldest and still most used algaecide is copper,
a cellular toxicant that comes in a wide variety of forms (Westerdahl and
Getsinger, 1988a).
Copper sulfate (CuSCXt) is the most common and basic form; it is registered
for use in potable waters, although restrictions apply in most states. Copper sul-
fate can be applied by towing burlap or nylon bags filled with granules (which dis-
solve) behind a boat, broadcasting granules, or injecting liquids. A copper slurry
can be delivered to an intended depth through a weighted hose.
The method of delivery is only one factor that influences effectiveness, how-
ever. In alkaline water (ISO mg calcium carbonate per liter, or more), hard water,
or water high in organic matter, copper can be quickly lost from solution and
thus rendered ineffective. In these cases, a liquid chelated form is often used. This
formulation allows the copper to remain dissolved in the water long enough to
kill algae.
Dilution is another important factor, as copper is often applied to only the
upper 10 feet of water to provide a refuge for zooplankton and sensitive fish spe-
cies. Vertical or horizontal mixing can rapidly decrease the treatment's effective-
ness.
248
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Most algae will be killed by doses of I to 2 mg CuSO4/L (0.4 to 0.8 mg Cu/L)
in hard water, while in soft water, doses of 0.3-0.5 mg CuSO4 are usually suffi-
cient. In most cases, cells disintegrate and release their contents into the water
column. Copper sulfate usually destroys many green and blue-green algae, and
nearly all diatoms, golden algae, dinoflagellates, cryptomonads, and euglenoids, al-
though sustained control may require additional applications. Such treatments
have been an important line of defense in drinking water supplies and have al-
lowed safe swimming by increasing water clarity in many recreational lakes.
However, some planktonic forms may not be affected by copper, including
certain species or strains of the filamentous blue-green algae Aphanizomenon, Os-
dllatoria, Phormidium, and Anabaena, and many species of the green algal order
Chlorococcales. Dense algal mats, especially those formed by members of the
green algal order Cladophorales, are resistant because copper cannot penetrate
past the outer layer of filaments. As these are some of the most severe nuisance
forms, copper treatments may eventually cause greater algal problems by not af-
fecting these forms while reducing other algae.
Algaecides can release taste and odor agents, other organic compounds, nu-
trients, and toxins into the water column, where they may remain a problem. In
killing certain species of blue-greens, algaecides may release toxins contained in
their cells (Kenefick et al. 1993) that can cause human illness. Although activated
carbon removes them in water treatment, simple filtration does not.
Some copper doses may also be acutely toxic to fish, although sublethal ef-
fects appear more likely (Cooke et al. 1993a). Zooplankton are especially sensi-
tive to copper; they may die or not be able to reproduce at concentrations lower
than some applied dosages. Loss of zooplankton eliminates food for many fish as
well as grazing control of algae. Some doses of copper may also affect certain
benthic invertebrates.
Fifty-eight years of copper sulfate treatment of several Minnesota lakes,
while sometimes temporarily controlling algae, appear to have:
• Depleted dissolved oxygen;
• Increased internal nutrient cycling;
• Occasionally killed fish;
• Accumulated copper in sediments;
• Increased tolerance to copper by some nuisance blue-green algae; and
• Negatively affected fish and zooplankton.
Hanson and Stefan (1984) concluded that short-term control of algae may
have been traded for long-term degradation of the lakes.
Not many alternatives to copper-based algaecides exist. Simazine, an or-
ganic formulation that proved highly effective against copper-resistant green algae,
was voluntarily taken off the market in 1996 because of potential human health
effects. Endothall (as the hydrothol formulation) and diquat are still used on
hard-to-kill greens and blue-greens, but water use is restricted for multiple days
after application, and diquat may be toxic to lake invertebrates. New formulations
of copper are more common than new non-copper-based algaecides. Selective al-
gaecides that take advantage of differences in cell wall composition, pigments, or
food storage are just beginning to appear.
Preventive techniques are preferable to counteractions; thus, algaecide treat-
ments should be timed to coincide with early phases of algal growth when algal
Jgaecides can
release taste and odor
agents/ other organic
compounds, nutrients,
and toxins into the
water column, where
they may remain a
problem.
249
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Managing Lakes and Reservoirs
I
If your lake needs
frequent algaecide
treatment^ then you
should develop a more
comprehensive
management plan.
sensitivity is greatest and deteriorating cells minimally affect the aquatic environ-
ment. Proper timing of application requires daily to weekly tracking of algal
populations; this may cost more than the actual total annual cost of the chemi-
cals.
Given the many negative aspects of algaecides, especially those involving
copper, such treatments should be used only as the last line of defense. If your
lake needs frequent algaecide treatment, then you should develop a more com-
prehensive management plan.
Phosphorus Iroactivatioin
Phosphorus inactivation controls algae by limiting phosphorus availability through
two processes:
• Using chemicals to remove (precipitate) phosphorus from the water
column; and
• Adding phosphorus binder to the lake to prevent release of
phosphorus from sediments.
Phosphorus inactivation is most effective after nutrient loading from the wa-
tershed declines, because it acts only on existing phosphorus reserves in the lake.
Aluminum has been widely used for phosphorus inactivation, mostly as
aluminum sulfate and sometimes as sodium aluminate or polyaluminum
chloride; it binds phosphorus well under a wide range of conditions, including
low oxygen. However, pH influences this process. In some cases, sodium alumi-
nate, which raises the pH, has been successfully used in combination with alumi-
num sulfate, which lowers the pH (Cooke et al. I993b). Buffering agents such as
lime and sodium hydroxide may also be added to the lake before treating with
aluminum sulfate.
Calcium hydroxide and ferric chloride successfully bind phosphorus;
the former tends to raise the pH and the latter lowers the pH slightly. Ferric
sulfate has also been applied, and lowers the pH substantially.
In practice, aluminum sulfate (often called alum) is added to the water
to form colloidal aggregates of aluminum hydroxide. These aggregates rapidly
grow into a visible, brownish-white floe, a precipitate that settles to the bottom
in a few hours to a few days, carrying phosphorus and bits of organic and inor-
ganic particulate matter.
After the floe settles, the water will be very clear. If enough alum is added, a
thin layer of aluminum hydroxide will cover the sediments and significantly retard
the release of phosphorus into the water column. In lakes where minimal nutri-
ents enter from the watershed, this can limit algal growth for a long time.
Treating lakes with low doses of alum may remove phosphorus from the wa-
ter column, but may not prevent phosphorus release from lake sediments over
the long term. Determining the dosage for inactivation of sediment phosphorus
depends on the form in which the phosphorus is bound (Welch and Rydin, 1999).
Good candidate lakes for phosphorus inactivation are those with low exter-
nal nutrient loads and high internal phosphorus release from sediment. High alka-
linity is also desirable to balance the pH when alum is used. Highly flushed
impoundments are usually not good candidates because phosphorus inputs are
difficult to control in such cases.
250
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Phosphorus inactivation has succeeded in some shallow lakes, but failed
where the external loads have not been previously controlled (Welch and
Schrieve, 1994; Welch and Cooke, 1999). Using jar tests to evaluate appropriate
dosage, successful doses have ranged from 3 to 30 g Al/m3 (15 to 50 g Al/m2)
with pH levels remaining above 6.0. Recent studies by Rydin and Welch (1988,
1999) have produced a method for measuring available sediment phosphorus and
determining the proper aluminum dose. Higher doses may be desirable if prop-
erly buffered. A 2:1 ratio of aluminum sulfate to sodium aluminate should main-
tain ambient pH, unless the pH is especially high because of excessive algal
photosynthesis, which will be reduced by treatment.
Aluminum sulfate is often applied near the thermocline depth (even before
stratification) in deep lakes, providing a refuge for fish and zooplankton that could
be affected by dissolved reactive aluminum. Application methods include modi-
fied harvesting equipment, outfitted pontoon boats, and specially designed barges.
Nutrient inactivation has received increasing attention over the last decade
as long-lasting results have been demonstrated in many projects, especially those
employing aluminum compounds (Welch and Cooke, 1999). Annabessacook
Lake in Maine suffered algal blooms for 40 years prior to the 1978 treatment
with aluminum sulfate and sodium aluminate (Cooke et al. 1993a). Internal phos-
phorus load decreased by 65 percent, blue-green algae blooms were eliminated,
and conditions have remained much improved for 20 years. Similarly impressive
results have been obtained in two other Maine lakes using the two aluminum
compounds together (Connor and Martin, 1989a).
Kezar Lake (New Hampshire) was treated with aluminum sulfate and so-
dium aluminate in 1984 after a wastewater treatment facility discharge was di-
verted from the lake. Both algal blooms and oxygen demand were depressed for
several years, but then reappeared more quickly than expected (Connor and
Martin, 1989a,b). Additional controls on external loads (wetland treatment of in-
flow) reversed this trend and conditions have remained markedly improved over
pre-treatment conditions for 15 years. No adverse impacts on fish or benthic
fauna have been observed.
Aluminum sulfate and sodium aluminate were again used with great success
at Lake Morey, Vermont (Smeltzer et al. 1999). Treatment in late spring 1987
reduced the average spring total phosphorus concentration from 37 u,g/L to 9
u,g/L Although epilimnetic phosphorus levels have varied since then, the pretreat-
ment levels have not yet been approached. Hypolimnetic phosphorus concentra-
tions have not exceeded 50 u.g/L Oxygen levels increased below the epilimnion,
with as much as 10 vertical feet of suitable trout habitat reclaimed. Some adverse
effects of the treatment on benthic invertebrates and yellow perch appear to
have been temporary.
Success has also been achieved with calcium (Babin et al. 1989; Murphy et al.
1990) and iron (Walker et al. 1989) salts, but it has become clear that aluminum
provides the greatest long-term binding potential for phosphorus inactivation
(Harper et al. 1999). The use of calcium would seem to be appropriate in high
pH lakes, and provides natural phosphorus inactivation in certain hardwater
lakes, but has been applied on only a small scale. Iron seems to be most useful in
conjunction with aeration systems. Aluminum salts can be used successfully in
any of these cases unless toxicity becomes a problem as a consequence of pH <
6.0 or > 8.5 (7.5 if sodium aluminate is used as a buffer).
Longevity of alum treatments has generally been excellent where external
inputs of phosphorus to the system have been controlled. As a general rule, inac-
tivation with aluminum can be expected to last for at least three flushing cycles,
N,
utrient inactivation
has received increasing ,
attention over the last
decade as long-lasting
results have been
demonstrated in many
projects/ especially those
employing aluminum
compounds. :
L
ongevity of alum
treatments has generally
been excellent where
external inputs of
phosphorus to the
system have been
controlled.
251
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Managing Lakes and Reservoirs
with much longer effectiveness where external loading has been controlled. A
review of 21 well-studied phosphorus inactivation treatments using aluminum
(Welch and Cooke, 1999) indicates that effects typically last 15 years or more
for dimictic (summer stratified) lakes and about 10 years for shallow, polymictic
(unstratified) lakes where the technique was appropriately applied.
Despite major successes, adding aluminum salts to lakes may cause serious
negative effects directly related to the alkalinity and pH of the lake water. Dosage
is therefore critical. In soft (low alkalinity) water, only very small doses of alum
can be added before the pH falls below 6.0. At pH 6.0 and below, AI(OH)2 and
dissolved elemental aluminum (Al+3) become dominant: both can be toxic to
aquatic life. Well-buffered, hardwater lakes can handle much higher alum doses
without fear of creating toxic forms of aluminum. Softwater lakes must be buff-
ered, either with sodium aluminate or other compounds, to prevent lowering pH
while forming enough AI(OH)3 to control phosphorus release.
Although pH depression is the major threat, elevated pH from over-
buffering can also cause problems. Hamblin Pond in Massachusetts was treated
with alum and sodium aluminate in 1995, after three years of pre-treatment study
that demonstrated both the importance of internal phosphorus loading and lim-
ited buffering capacity (Wagner, in review). A number of problems arose during
the treatment, resulting in an overdose of sodium aluminate throughout the lake.
The pH rose from about 6.3 to over 9.0, resulting in a fishkill. The treatment in-
creased the summer water transparency fivefold —and gained 10 vertical feet of
coldwater fish habitat — but state agencies remain skeptical about this technique
because of the fishkill.
Concerns about aluminum treatments include:
• Although the sharp increase in water transparency is usually desirable,
it may allow an existing rooted plant infestation to spread into new
areas or deeper water.
• The sulfates in an aluminum sulfate treatment may foster chemical
reactions that disrupt the iron cycle and associated natural
phosphorus binding capacity.
• Aluminum sulfate treatments that reduce the pH may cause
decalcification in sensitive organisms and limit calcium control of
phosphorus cycling.
• Aluminum toxicity to humans has created substantial public
controversy about this treatment, but scientific investigations do not
support these concerns (Krishnan, 1988).
Before using phosphorus inactivation to control algae, consult a professional
who thoroughly understands your lake's chemistry.
Sediment Oxidation
Like aeration, drawdown, and phosphorus inactivation, sediment oxidation is de-
signed to decrease phosphorus release from sediments. Called Riplox after its orig-
inator, Wilhelm Ripl, the procedure injects calcium nitrate into the top 10 inches of
sediments to break down (oxidize) organic matter and promote denitrification.
If sediments are low in iron, ferric chloride or similar compounds can first
be added to enhance phosphorus binding. Lime can also help raise sediment pH
to the optimum 7.0-7.5.
252
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Ripl (1976) first treated Lake Lillesjon, a 10.5-acre Swedish lake with a 6.6-
foot mean depth. The treatment dramatically lowered sediment phosphorus re-
lease and lasted at least two years. A portion of a Minnesota lake was also
treated, but high external loading overwhelmed the effects.
No negative impacts have been reported, but the impact on benthic commu-
nities from the chemical reactions could be severe. However, where this tech-
nique is appropriate, a significant benthic community will probably not exist prior
to treatment.
Although developed in the 1970s, this technique is not widely used and needs
further experimentation. Oxidation and other reactions that change sediment
chemistry may be able to control internal loads of a variety of contaminants.
Settling Agents
Although the water treatment industry has long used coagulants to enhance set-
tling and filtration, lakes have used such agents —principally alum and calcium
compounds — not so much to directly remove algae as to indirectly control it by
inactivating phosphorus (Babin et al. 1989; Murphy et al. 1990). Such treatments,
however, do cause most algae to settle to the bottom. Various polymers could
also be used, but their usage has not been documented.
The primary value of this technique is that it removes algal cells from the
water column, rather than allowing them to release their contents throughout
the lake. Settling may eventually result in release of cellular contents, but not rap-
idly and not throughout the water column.
Not all algal species settle, however; many buoyant blue-green species resist
settling unless a strong floe layer develops and sweeps them out of the water col-
umn. In such cases, underdosing may not significantly reduce algal densities, or
may form unsightly macroscopic clumps.
Selective Nutrient Addition
This is a theoretical approach that has not been subjected to widespread practical
study. In theory, a change in nutrient ratios should drive a shift in algal composi-
tion to species better suited to the new ratio (Tilman, 1982). If algae more prefer-
able to zooplankton become dominant, algal biomass may decline. Laboratory and
some whole lake experiments support this theory, but practical applications are
lacking.
In reality, competitive forces seem weak compared to predation, and
changes in environmental conditions might limit competitive effects. While this
approach may work under certain circumstances, it is unlikely to become a com-
mon lake management technique.
An alternative nutrient strategy involves adding nitrate to an anoxic hypo-
limnion (Kortmann and Rich, 1994) to limit generation of sulfides from sulfates,
reduce iron-sulfide reactions, and enhance iron-phosphorus binding. Nitrogen
would be released as a gas, minimizing uptake by algae. Nitrogen could also be
added as aluminum nitrate or ferric nitrate to promote phosphorus binding. Cold
groundwater high in nitrates might be used for this purpose. Although theoreti-
cally sound, this approach needs well-documented practical applications.
253
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Managing Lakes and Reservoirs
Management to Reduce Nutrient Input
Biomanipulation:
The alteration of one or more
biological components of an
aquatic system to cause other
biological components or
water quality to change in a
desired manner.
Techniques in this category are largely watershed management methods (see
Chapter 6). The boundary blurs, however, when part of the lake is used to treat
incoming water — or when runoff is treated with phosphorus inactivators prior
to discharge to a lake, where the floe then settles (Harper et al. 1999). The princi-
ples and experience set forth in Chapters 2 and 6 apply, but it is important to rec-
ognize that, with proper planning and implementation, part of the lake itself can
treat watershed-based pollutants.
Enhanced Grazing
Grazing can be a powerful force in structuring the algal community. It is one of a
group of procedures called "biomanipulation" that Shapiro et al. (1975) suggested
could greatly improve lake quality without using expensive machines or chemicals.
Biomanipulation depends on general ecological principles to manipulate the lake's
biological components to produce desired conditions, and has performed satisfac-
torily in many systems.
At times, grazing zooplankton and not the quantity of nutrients control the
amount of algae in open water (McQueen et al. 1986). Even if productivity is high,
grazing prevents biomass from accumulating. Zooplankters are microscopic, often
crustacean animals found in every lake, but at different densities and varying sizes.
A sufficient population of large-bodied herbivorous zooplankters (preferably
Daphnia) can filter the entire epilimnion each day during the summer as they
graze on algae, bacteria, and organic matter.
Although some algae are immune to grazing, continual strong grazing can re-
duce algae overall and increase transparency. Excessive nutrients may stimulate
growth by resistant algae to overcome this effect, but, usually, large-bodied graz-
ers will maintain the lowest possible algal biomass and highest possible clarity
(Lathrop et al. 1999) for the level of fertility in the lake. If the lake is otherwise
very turbid, grazing may have no observable effect.
Large-bodied grazers are not common everywhere, however.
• They won't be found in some lakes, such as Florida's subtropical lakes.
• In many others they're eaten by certain fish, including the fry of nearly
every fish species and the adults of bluegill, pumpkinseed, perch, shad,
alewife, shiners, and others. In lakes dominated by adult species such as
largemouth bass, walleye, and northern pike, large-bodied zooplankton
are more likely to be abundant because those fish have eaten the
predators of the zooplankton.
Other conditions that might reduce the population of large-bodied zoo-
plankton include:
• An anoxic metalimnion or hypolimnion, common in eutrophic lakes,
that eliminates these zones as daytime refuges for zooplankton from
visually feeding fish (aeration can eliminate this problem);
• The toxic effect of pesticides that enter the lake with runoff; and
• Copper sulfate used for temporary algal control can also kill
zooplankton at doses below those needed for algae control.
Severe mortality of zooplankton appears responsible for the commonly ob-
served rebound of algae following a copper treatment (Cooke and Kennedy, 1989).
254
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Algal control by animals in the food chain is called "top-down," unlike the
more common "bottom-up" algal control through nutrient limitation. Figure 7-3
depicts these food web interactions, which vary considerably over space and time.
To increase the large-bodied zooplankton population, you must reduce the
number of zooplankton-eating fish (Hosper and Meijer, 1993; Dettmers and Stein,
1996). Either stock more piscivorous fish or get rid of the planktivores by using
such techniques as water level drawdown, winterkill, netting, or electroshocking
— even poison them as a last resort.
Removing planktivores by hook and line is usually a hopeless task. But just
the act of fishing points to a potential conflict. In lakes where sport fishing is the
first priority, planktivorous fish form an essential food web link in the fishery. So
how do you manage both for a trophy gamefish population (which needs
zooplankton-eaters) and for the clearest possible water (which needs zooplank-
ton)? Controlling the density of stunted panfish appears to serve both goals and
has improved both water clarity and fishing (Wagner, 1986).
Algae-eating fish might control algal biomass if stocked in sufficient quanti-
ties. However, no native species of fish in the United States consumes enough al-
gae to be effective, so non-native species (e.g., Tilapia), probably of tropical origin,
would have to be introduced. Given the track record of introduced species (Mills
et al. 1994), this does not appear to be a desirable approach, and many states have
banned such introductions. In addition:
• The excreted nutrients from such fish might also support the growth
of as much algae as those fish could consume.
• No fish can efficiently feed on the smallest algal cells, perhaps resulting
in a shift toward smaller cell size and greater turbidity per unit of algal
biomass present.
• Tropical species such as Tilapia are unlikely to overwinter in the more
northern states, limiting the duration of any effect.
Removal of Bottom-feeding Fish
Another type of biomanipulation that could improve lake transparency is eliminat-
ing fish such as the common carp or bullheads that are bottom browsers.
Browsing releases significant amounts of nutrients to the water column as these
fish feed and digest food. Harvesting these fish has increased clarity in some cases,
but removing them can be very difficult since they tolerate very low levels of dis-
solved oxygen and high doses of fish poisons. Labor-intensive programs appear nec-
essary to substantiality reduce bottom-feeding fish populations (McComas, 1993),
unless the entire fish population can be eliminated through complete drawdown,
complete freezing, or extremely high doses of rotenone or other fish poisons.
Of particular interest is the grass carp, which has been placed in many lakes
to control nuisance plants. Shallow, fertile lakes appear to have alternative stable
states dominated by either rooted plants or algae (Scheffer et al. 1993). Removing
the rooted plants may induce algal blooms and worsen conditions for many lake
uses. The grass carp may also add enough nutrients to the water column to sup-
port algal blooms. Grass carp baits and traps are now sold, but an entire popula-
tion is difficult to completely remove. If the fish are sterile, they will eventually die
off, but the algae blooms may persist in the absence of vascular plants.
255
-------
NATURAL FORCES
*Weather
'Habitat Suitability
HUMAN ACTIONS
Fish Stocking
*Fish Removal
'Habitat Alteration
Low Piscivore Biomass
High Piscivore Biomass
High Planktivore Biomass
Bottom-feeding Fishes
Low Planktivore Biomass
(+young
piscivore
species)
(+young
piscivore
species)
Low Zooplankton Biomass
and Mean Length
High Zooplankton Biomass
and Mean Length
Carnivorous Zooplankton
High Phytoplankton
Biomass and Range of
Particle Sizes
Low Phytoplankton
Biomass and Larger
Particle Sizes
Nutrient Availability and Ratios
Lower Water Clarity per
Unit of Fertility, Often
Elevated pH and Added
Oxygen Stress
Non-Algal Solids,
Incoming Water
Quality and Flushing
Rate
Higher Water Clarity per
Unit of Fertility, Limited
Effect on pH and
Oxygen Level
Figure 7-3.—Role of fish community structure in determining plankton features and water clarity.
256
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Pathogens
Viral, bacterial, and fungal pathogens have each been explored as possible control
methods for algae. Ideally, a lake would be inoculated with a pathogen that targets
either a broad spectrum of algae, or a few especially obnoxious species. Such
pathogens have been tried (Lindmark, 1979), but none has proven effective and
controllable. The complexity of biological interactions appears beyond our sus-
tained control, and although we can set processes in motion to produce desired
conditions in a lake, those conditions tend to be temporary.
Competition and Allelopathy
Negative interactions between rooted plants and algae might be harnessed to
control algal biomass, but they also might create a macrophyte nuisance. Com-
mercially marketed "nutri-pods" incorporate rooted or floating plants into a
floating structure from which excess biomass can be removed as it develops. The
success of this approach has not been scientifically documented, but it has no ap-
parent adverse ecological impacts as long as native, non-nuisance species are used.
Competition is also used at the bacterial level, using microbial additives
developed largely in the wastewater treatment industry. According to product lit-
erature, these microbes limit the availability of nutrients essential for algal
growth, thus reducing algal blooms. The products surveyed are primarily
denitrifiers, removing nitrogen from the system and creating a nitrogen limitation
on growth. However, little scientific documentation of this technique's effects in
lakes exists, and reduction of nitrogen:phosphorus ratios favors certain nui-
sance-type blue-green algae.
Plantings to reduce light penetration might control algae, but also produce
many negative side effects. Surface-covering growths of duckweed, water hya-
cinth, or water chestnut could provide such a light barrier, but at great expense
to habitat and water quality.
Although aging rooted plants often release nutrients that cause algal blooms,
release of allelopathic substances during the plants' more active growth
phase may inhibit algal growth. Mat-forming algae in rooted plant beds appear un-
affected, but many more planktonic algal species decline when rooted plant
growths are dense. This may represent a trade-off between an algal nuisance and
a rooted plant nuisance, and many lakes have both.
Barley straw appears to be able to control algal densities (Barrett et al.
1996; Wynn and Langeland, 1996), and combines features of algaecides,
allelopathy, and competition. Preferably added to shallow, moving water or from
pond-side digesters, decaying barley straw gives off substances that inhibit algal
growth, especially that of blue-green algae. Although not a thoroughly under-
stood technique, research conducted mainly in England has demonstrated that
the decomposition of the barley straw produces allelopathic compounds that act
as algaecides. Microbial activity may also compete with algae for nutrients.
Doses of barley straw under well-oxygenated conditions are typically
around 2.5 g/m2 of pond surface, with doses of 50 g/m2 or more necessary where
initial algal densities are high or flow is limited. Doses of 100 g/m2 may cause oxy-
gen stress in the pond as decomposition proceeds, but this might be avoided by
using a land-based digester into which straw is deposited and through which wa-
ter is pumped as the straw decays.
Allelopathy: Control of one
plant by another through
chemical releases.
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Managing Lakes and Reservoirs
Nuisance Vascular Plants
Overabundant rooted and floating vascular plants create a major nuisance for
most lake and reservoir users. In extreme cases, particularly in ponds and in shal-
low, warm, well-lighted lakes and waterways of the southern United States, weeds
can cover the entire lake surface and fill most of the water column. Obviously,
plants can be both desirable and attractive, but unwanted plant (weed) infesta-
tions interfere with recreation, detract from aesthetic value, and can impair habi-
tat as well. They can also introduce significant quantities of nutrients and organic
matter to the water column, stimulating algal blooms and causing damaging fluc-
tuations in dissolved oxygen.
Macrophytes (vascular plants and visible algal mats) are generally grouped into
classes called emergents (such as alligatorweed and cattails), floating-leaved
(water hyacinth and water lilies), and submergents (hydrilla, milfoil, and naiads),
plus the mats of filamentous algae discussed in the nuisance algae section of this
chapter. Understanding the factors that control plant growth is the first step in
controlling weeds.
• Macrophytes reproduce by producing flowers and seeds and/or
asexually from stem fragments or shoots extending from roots. The
primary means of reproduction is an extremely important feature of a
plant, and will greatly affect the applicability of control methods.
• Growth rates of macrophytes, especially non-native species like water
hyacinth, hydrilla, and milfoil, can be very high, largely related to
substrate and light conditions. Submergent plants grow profusely only
when they have enough light underwater. Highly turbid lakes and
reservoirs probably won't have dense beds of submerged plants.
Significant reductions in algal blooms can also enhance light
penetration and allow weeds to grow more extensively and densely.
• High silt loads can create a favorable plant substrate, but the silt may
also cause severe turbidity, which limits growth.
• Steep-sided lakes support a much smaller plant community as a
consequence of both peripheral substrate and light limitations.
• A few plants, including water hyacinth, water lettuce, duckweed, and
watermeal, can float on the surface with no roots in the sediment,
nearly eliminating substrate and light as key control factors.
• Most macrophytes (but certainly not all) obtain most of their nutrition
from the sediment through roots. This is an important ecological
feature, because they're not affected by the reduction of nutrient
concentrations in the water column. When the sediments are either
highly organic (very loose muck) or inorganic (rock to coarse sand),
macrophytes may grow poorly because their roots can't take hold and
obtain nutrients in either sediment type. In these two extremes,
emergent plants may replace submergents in shallow water because
their more extensive root systems are better adapted to these
conditions.
Plant groupings and controls vary with geography. In southern states border-
ing the coast, plants grow most of the year, often rapidly, into long-lived, dense,
and expansive growths of vegetation. Most non-native species are found there;
258
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CHAPTER 7: Management Techniques Within the Lafce or Reservoir
they can out-compete many more desirable native species for space. Aquatic
plant management in these ecosystems often requires methods that might seem
extreme in northern ecosystems.
Northern lakes and reservoirs have their share of weed infestations, but
seasonal changes in light and temperature tend to limit nuisance conditions to
the summer. As this corresponds with the period of greatest human use of lakes,
however, plants usually need to be managed. However, opinions on the level and
forms of control vary more than in southern regions.
Setting goals for rooted plant control is a critical planning step and the
choice of management technique(s) depends on those goals. Ecologically, most
lakes need a certain amount of plants; often a balance between rooted plants and
algae must be recognized. Where fishing is the primary objective, substantial bot-
tom coverage is desirable, with some vertical and horizontal structure created by
different species of plants to enhance the habitat for different fish species or life
stages. For swimming purposes, having no plants seems safer, but a low, dense
cover in shallow lakes with silty bottoms can minimize turbidity, another safety
concern.
Perhaps the simplest axiom for plant management is that if light penetrates
to the bottom and the substrate is not rock or cobble, plants will grow. A pro-
gram intended to eliminate all plants is both unnatural and maintenance intensive,
if possible. A program to structure the plant community to meet clear goals in an
ecologically and ethically sound manner is more appropriate, although often quite
expensive.
Table 7-5 overviews the techniques used to control rooted plants, with
notes on the action, advantages, and disadvantages of each technique. Additional
details are provided in narrative form here and in Cooke et al. I993a, and Hoyer
and Canfield, 1997.
Benfhic Barriers
These bottom covers work on the principle that rooted plants require light and
cannot grow through physical barriers.
^ Natural benthic barriers: Clay, silt, sand, and gravel have been used
for many years, although plants often root in these covers eventually, and
current environmental regulations usually won't approve depositing such fill.
In the reverse layering technique (KVA, 1991) sand is pumped from beneath
a muck or silt layer and deposited as a new layer on top. Technically, this is
reorganizing the sediments, not new fill. Although expensive on a large scale
and dependent on the composition of the sediment, this technique may re-
store the natural lake bottom without removing sediment.
V Artificial benthic barriers: Over the last three decades, various
materials, including polyethylene, polypropylene, fiberglass, and nylon
sheets have been developed to cover sediments. Available in both solid
and porous forms, manufactured benthic barriers cover plants to limit
light, physically disrupt growth, and allow chemical reactions to restrict
plant development (Perkins et al. 1980).
program to i
structure the plant i
community to meet clear
goals in an ecologically
and ethically sound
manner is more .j
appropriate, although
often quite expensive. \
Benthic: Refers to life or
things found on the bottom of
a lake.
259
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Managing Lakes and Reservoirs
Table 7-5.— Management options for control of rooted aquatic plants.
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS . i .; •...-, -„•-,_ :• -J... -..-;• ;.-: -JV.V; :.:',.,,,.:,,•;.;<:,;:,.:;::. ^, ,-:,',,;,,.;..,:„
1 . Benthic barriers
1 .a.Porous or
loose-weave
synthetic
materials
1 .b.Non-porous
or sheet
synthetic
materials
I.e. Sediments of
a desirable
composition
*Mat of variable composition laid
on bottom of target area
»Can cover area for as little as
several weeks or permanently
•Maintenance improves
effectiveness
•Most often used in swimming
areas and around docks
• Laid on bottom and usually
anchored by sparse weights or
stakes
* Removed and cleaned or flipped
and repositioned at least once per
year for maximum effectiveness
•Laid on bottom and anchored by
many stakes, anchors, or weights,
or by layer of sand
•Not typically removed, but may
be swept or blown clean
periodically
* Sediments may be added on top
of existing sediments or plants
•Use of sand or clay can limit plant
growths and alter sediment-water
interactions
* Sediments can be applied from
the surface or suction-dredged
from below muck layer (reverse
layering technique)
* Prevents plant growth
* Reduces turbidity from soft
sediment
• Can cover undesirable substrate
•Can improve fish habitat
* Allows some escape of gases
which may build up underneath
» Panels may be flipped in place or
removed for relatively easy
cleaning or repositioning
» Prevents all plant growth until
buried by sediment
»Minimizes interaction of sediment
and water column
* Plant biomass can be buried
• Seed banks can be buried deeper
•Sediment can be made less
hospitable to plant growths
•Nutrient release from sediments
may be reduced
•Surface sediment can be made
more appealing to human users
•Reverse layering requires no
addition or removal of sediment
•May cause anoxia at
sediment-water interface
•May limit benthic invertebrates
•May interfere non-selectively with
plants in target area
•May inhibit spawning or feeding
by some fish
•Allows some growth through pores
•Gas may still build up underneath
in some cases
•Gas buildup may cause barrier to
float upwards
• Strong anchoring makes removal
difficult and can hinder
maintenance
•Lake depth may decline
•Sediments may sink into or mix
with underlying muck
•Permitting for added sediment
may be difficult
•Addition of sediment may increase
turbidity initially
* New sediment may contain
nutrients or other contaminants
•Generally too expensive for large-
scale application
260
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-5.— Management options for control of rooted aquatic plants (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
.". • • '-•-...;. -, •$"f1'-SJi&» f & &S" "» ?» *
PHYSICAL CONTROLS
2. Dredging
2. a. "Dry"excavation
2.b "Wet" excavation
2.c. Hydraulic removal
* Sediment is physically removed by
wet or dry excavation, with
deposition in a containment area
for dewatering/disposal
* Dredging can be applied on a
limited basis, but is most often a
major restructuring of a severely
impacted system
» Plants and seed beds are removed
and re-growth can be limited by
light and/or substrate limitation
*Lake drained or lowered to
maximum extent practical
* Target material dried to maximum
extent possible
* Conventional excavation
equipment used to remove
sediments
Hake level may be lowered, but
sediments not substantially
dewatered
* Draglines, bucket dredges, or
long-reach backhoes used to
remove sediment
*Lake level not reduced
» Suction or cutterhead dredges
create slurry which is hydraulically
' pumped to containment area
» Slurry is dewatered; sediment
retained, water discharged
» Achieves plant removal with some
flexibility
* Increases water depth
*Can reduce pollutant reserves
»Can reduce sediment oxygen
demand
*Can improve spawning habitat for
many fish species
* Allows complete renovation of
aquatic ecosystem
» Tends to facilitate a very thorough
effort
*May allow drying of sediments
prior to removal
» Allows use of less specialized
equipment
* Requires least preparation time or
effort; tends to be least costly
dredging approach
»May allow use of easily acquired
equipment
*May preserve most aquatic biota
*Creates minimal turbidity and
limits impact on biota
»Can allow some lake uses during
dredging
*Allows removal with limited
access or shoreline disturbance
temporarily removes benthic
invertebrates
*May create turbidity
*May eliminate fish community
(complete dry dredging only)
*May cause impacts from
containment area discharge
*May cause impacts from dredged
material disposal
*May interfere with recreation or
other uses during dredging
* Usually very expensive
* Eliminates most aquatic biota
unless a portion left undrained
* Eliminates lake use during
dredging
» Risks downstream turbidity during
storms
* Usually creates extreme turbidity
*Tends to result in sediment
deposition in surrounding area
* Normally requires intermediate
containment area to dry sediments
prior to hauling
*May cause severe disruption of
ecological function
» Usually eliminates most lake uses
during dredging
* Often leaves some sediment
behind
* Requires sophisticated and more
expensive containment area or
advanced dewatering system
* Cannot handle extremely coarse
or debris-laden materials
» Requires overflow discharge from
containment area
261
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Managing Lakes and Reservoirs
Table 7-5.—Management options for control of rooted aquatic plants (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS
3. Dyes and surface
covers
> Water-soluble dye is mixed with
lake water, thereby limiting light
penetration and inhibiting plant
growth
»Dyes remain in solution until
washed out of system
* Opaque sheet material applied to
water surface
* Limits light on plant growth without
high turbidity or great depth
*May achieve some control of
algae as well
»May achieve some selectivity for
species tolerant of low light
*May not control peripheral or
shallow-water rooted plants
>May cause thermal stratification in
shallow ponds
»May facilitate anoxia at sediment
interface with water
* Covers inhibit gas exchange with
atmosphere
4. Mechanical
removal
* Plants reduced by mechanical
means, possibly with disturbance
of soils
* Highly flexible control
+ May impact aquatic fauna
»Collected plants may be placed
on shore for composting or other
disposal
»May remove other debris
» Non-selectively removes plants in
treated area
* Wide range of techniques
employed, from manual to highly
mechanized
>Can balance habitat and
recreational needs
*May spread undesirable species
by fragmentation
»Application once or twice per
year usually needed
»May generate turbidity
4.a. Hand pulling
* Plants uprooted by hand
("weeding") and preferably
removed
* Highly selective technique
> Labor intensive
4.b. Cutting
(without collection)
* Plants cut in place above roots
without being harvested
*May employ grinder to more
completely destroy vegetation
* Generally efficient and less
expensive than complete
harvesting
» Leaves root systems and part of
plant for re-growth
> Leaves cut vegetation to decay or
to re-root
>Not selective within applied area
4.c. Harvesting
(with collection)
» Plants cut at depth of 2-10 ft and
collected for removal from lake
* Allows plant removal on greater
scale
>Limits depth of operation
» Usually leaves fragments which
may re-root and spread infestation
»May impact lake fauna
>Not selective within applied area
>More expensive than cutting
4.d. Rototilling
» Plants, root systems, and
surrounding sediment disturbed
with mechanical blades
*Can thoroughly disrupt entire
plant
> Usually leaves fragments which
may re-root and spread infestation
>May impact lake fauna
> Not selective within applied area
» Creates substantial turbidity
»More expensive than harvesting
262
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-5.— Management options for control of rooted aquatic plants (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
PHYSICAL CONTROLS ' ' *'*+"»"+* ,,.,-—. , ^ ^»
:.' - - - -..;• - :..--< • • ^ ' * *%s*w * -°% *«,* *> i * ** *^B*tas%*^tw ^rf^fc*. *feaewv ^* st^ .« *, ^ « , JW.WA*
4.e.Hydroraking
5. Water level control
5. a. Drawdown
5.b. Flooding
* Plants, root systems, and
surrounding sediment and debris
disturbed with mechanical rake;
part of material usually collected
and removed from lake
* Lowering or raising the wafer level
to create an inhospitable
environment for some or all
aquatic plants
* Disrupts plant life cycle by
dessication, freezing, or light
limitation
* Lowering of water over winter
allows freezing, dessication, and
physical disruption of plants
» Timing and duration of exposure
and degree of dewatering are
critical aspects
*Variable species tolerance to
drawdown; emergent species and
seed-bearers are less affected
»Most effective on annual to
once/3 yr. basis
* Higher water level in the spring
can inhibit seed germination and
plant growth
* Higher flows that are normally
associated with elevated water
levels can flush seed and plant
fragments from system
*Can thoroughly disrupt entire
plant
*Also allows removal of stumps or
other obstructions
* Requires only outlet control to
affect large area
* Provides widespread control in
increments of water depth
»Complements certain other
techniques (dredging, flushing)
* Provides control with some
flexibility
» Provides opportunity for shoreline
clean-up/structure repair
»May help with flood control
* Impacts vegetative propagation
species with limited impact to
seed-producing populations
* Where water is available, this can
be an inexpensive technique
* Plant growth need not be
eliminated, merely retarded or
delayed
* Timing of water level control can
selectively favor certain desirable
species
*• Usually leaves fragments which
may re-root and spread infestation
*May impact lake fauna
*Not selective within applied area
»Creates substantial turbidity
»More expensive than harvesting
»May create potential issues with
water supply
»May have potential issues with
flooding
*May impact non-target flora and
fauna
*May impact contiguous emergent
wetlands
*May affect overwintering reptiles
and amphibians
*May impair well production
*May reduce potential water
supply and fire fighting capacity
*May alter downstream flows
*May cause overwinter water level
variation
»May cause shoreline erosion and
slumping
»May result in greater nutrient
availability for algae
» Water for raising the level may
not be available
*May cause peripheral flooding,
and/or property damage
»May have downstream impacts
»Many species may not be affected,
and some may benefit
* Algal nuisances may increase
where nutrients are available
263
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Managing Lakes and Reservoirs
Table 7-5.— Management options for control of rooted aquatic plants (continued).
OPTION
MODE OF ACTION
ADVANTAGES,
DISADVANTAGES
:CHEMICAL CONTROLS
6. Herbicides
6.a. Forms of copper
6.b. Forms oF endothall
(7-oxabtcyclo [2.2.1]
hoplano-2,
SJiCdfboxyltc acid)
6.c.Forms of diquat
(6,7-dihydropyrido
n,2.2M'<]
pyrazinedifum
dibromida]
* Liquid or pelleKzed herbicides
applied to target area or to plants
directly
* Contact or systemic chemicals kill
plants or limit growth
•Typically requires application
every 1 -5 yrs
* Contact herbicide
* Cellular toxicant, suspected
membrane transport disruption
•Applied as wide variety of liquid
or granular formulations, often in
conjunction with surfactants or
other herbicides
* Contact herbicide with limited
translocation potential
* Membrane-active chemical that
inhibits protein synthesis
•Causes structural deterioration
•Applied as liquid or granules
•Contact herbicide
•Absorbed by foliage but not roots
•Strong oxidant; disrupts most
cellular functions
•Applied as a liquid, sometimes in
conjunction with copper
•Wide range of control is possible
•May be able to selectively
eliminate species
•May achieve some algae control
as well
•Moderately effective control of
some submersed plant species
•More often an algal control agent
• Exerts moderate control of some
emersed plant species, moderately
to highly effective control of
floating and submersed species
•Has limited toxicity to fish at
recommended dosages
•Acts rapidly
• Exerts moderate control of some
emersed plant species, moderately
to highly effective control of
floating or submersed species
•Has limited toxicity to fish at
recommended dosages
•Acts rapidly
•May be toxic to non-target species
of plants/animals
* Possible downstream impacts;
may affect non-target areas within
pond
•May restrict water use for varying
time after treatment
•May increase oxygen demand
from decaying vegetation
•May cause recycling of nutrients
to allow other growths
•Toxic to aquatic fauna as a
function of concentration,
formulation, and ambient water
chemistry
•Ineffective at colder temperatures
•Copper ion persistent;
accumulates in sediments or
moves downstream
•Non-selective in treated area
•May be toxic to aquatic fauna
(varying degrees by formulation)
•Time delays necessary on use for
water supply, agriculture, and
contact recreation
•Non-selective in treated area
•Sometimes toxic to zooplankton at
recommended dosage
•Inactivated by suspended
particles; ineffective in muddy
waters
•Time delays necessary on use for
water supply, agriculture, and
contact recreation
264
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-5.— Management options for control of rooted aquatic plants (continued).
OPTION
CHEMICAL CONTROLS
6.d. Forms of
glyphosate
(N phosphonom
ethyl glycine)
6.e. Forms of 2,4-D
(2,4-dichlorophenoxy
acetic acid)
6.f. Forms of fluridone
( 1 -methyl-3-phenyl-
5-[-3-{trifluoromethy]}
phenyl]-
4[IH]-pyridinone)
6.g. Forms of triclopyr
(3,5,6-trichloro-
2-pyridinyloxyacetic
acid)
MODE OF ACTION
~( « i
• Contact herbicide
* Absorbed through foliage;
disrupts enzyme formation and
function in uncertain manner
* Applied as liquid spray
» Systemic herbicide
» Readily absorbed and
translocated throughout plant
* Inhibits cell division in new tissue,
stimulates growth in older tissue,
resulting in gradual cell disruption
* Applied as liquid or granules,
frequently as part of more complex
formulations, preferably during
early growth phase of plants
» Systemic herbicide
* Inhibits carotenoid pigment
synthesis and impacts
photosynthesis
•Best applied as liquid or granules
during early growth phase of
plants
* Systemic herbicide, registered for
experimental aquatic use by
cooperators in selected areas only
at this time
* Readily absorbed by foliage,
translocated throughout plant
* Disrupts enzyme systems specific
to plants
•Applied as liquid spray or
subsurface injected liquid
ADVANTAGES
•
•Exerts moderately to highly
effective control of emersed and
floating plant species
•Can be used selectively, based on
application to individual plants
•Acts rapidly
•Low toxicily to aquatic fauna at
recommended dosages
•No time delays needed for use of
treated water
•Moderately to highly effective
control of a variety of emersed,
floating and submersed plants
•Can achieve some selectivity
through application timing and
concentration
•Fairly fast action
•Can be used selectively, based on
concentration
•Gradual deterioration of affected
plants limits impact on oxygen
level (BOD)
* Effective against several
difficult-to-control species
•Low toxicity to aquatic fauna
•Effectively controls many floating
and submersed plant species
•Can be used selectively; more
effective against dicot plant
species, including many nuisance
forms
•Effective against several
difficult-to-control species
•Low toxicity to aquatic fauna
•Acts rapidly
DISADVANTAGES
• Non-selective in treated area
•Inactivated by suspended
particles; ineffective in muddy
waters
•Not for use within 0.5 miles of
potable water intakes
* Highly corrosive; storage
precautions necessary
•Has variable toxicity to aquatic
fauna, depending upon
formulation and ambient water
chemistry
•Time delays necessary for use of
treated water for agriculture and
contact recreation
• Not for use in water supplies
•Impacts on non-target plant
species possible at higher doses
•Extremely soluble and mixable;
difficult to perform partial lake
treatments
•Requires extended contact time
(40 days recommended)
•Impacts on non-target plant
species possible at higher doses
•Current time delay of 30 days on
consumption of fish from treated
areas
•Necessary restrictions on use of
treated water for supply or contact
recreation not yet certain
265
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Managing Lakes and Reservoirs
Table 7-5.— Management options for control of rooted aquatic plants (continued).
OPTION
MODE OF ACTION
ADVANTAGES
DISADVANTAGES
'». I'' • ,1'JUU'i'" .,! ",' 1 ' :.,!„.. . ! " , ,i' , .!!,,, I '. ' ', ,,!', ' .1, » ,)' Jtt Iff? f ft^f *Jft !" f&P t
BIOLOGICAL CONTROLS
•_ *. *s*%
7. Biological
introductions
7.a. Herbivorous fish
7.b. Herbivorous
insects
7.c. Fungal/bacterial/
viral pathogens
7.d. Selective plantings
•Fish, insects, or pathogens that
feed on or parasitize plants are
added to system to effect control
•The most commonly used
organism is the grass carp, but the
larvae of several insects have
been used more recently, and
viruses have been tested
* Sterile juveniles stocked at density
that allows control over multiple
years
* Growth of individuals offsets
losses or may increase
herbivorous pressure
* Larvae or adults stocked at density
intended to allow control with
limited growth
* Intended to selectively control
target species
•Milfoil weevil becoming popular,
but still experimental
* Inoculum used to seed lake or
target plant patch
* Growth of pathogen population
expected to achieve control over
target species
•Establishment of plant assemblage
resistant to undesirable species
• Plants introduced as seeds,
cuttings, or whole plants
* Provides potentially continuing
control with one treatment
* Harnesses biological interactions
to produce desired conditions
•May produce potentially useful
fish biomass as an end product
*May greatly reduce plant biomass
in single season
•May provide multiple years of
control from single stocking
•Sterility intended to prevent
population perpetuation and allow
later adjustments
•May involve species native to
region, or even targeted lake
• Expected to have no negative
effect on non-target species
•May facilitate longer-term control
with limited management
•May be highly species specific
•May provide substantial control
after minimal inoculation effort
•Can restore native assemblage
•Can encourage assemblage most
suitable to lake uses
•Supplements targeted species
removal techniques
•Typically involves introduction of
non-native species
•Effects may not be controllable
•Plant selectivity may not match
desired target species
•May adversely affect indigenous
species
•May eliminate all plant biomass,
or impact non-target species more
than target forms
•Funnels energy into largely unused
fish biomass and algae
•May drastically alter habitat
•May escape to new habitats
upstream or downstream
•Population control uncertain unless
absolutely sterile
• Population ecology suggests
incomplete control likely
•Oscillating cycle of control and
re-growth likely
•Predation by fish may complicate
control
•Other lake management actions
may interfere with success
•Largely experimental; effectiveness
and longevity of control not well
known
•Infection ecology suggests
complete control unlikely
• Possible side effects not well
understood
•Largely experimental at this time;
few well-documented cases
•Nuisance species may eventually
outcompete established
assemblage
•Introduced species may become
nuisances
266
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Benthic barriers can control plant growth in small areas such as dock spaces
and swimming beaches. They're also practical for creating access lanes and struc-
tural habitats. Large areas are not often treated, however, because the cost of ma-
terials and application is high and maintenance can be problematic (Engel, 1984).
Benthic barrier problems of prime concern:
• Long-term integrity of the barrier;
• Billowing caused by trapped gases;
• Accumulation of sediment on top of barriers;
• Growth of plants on porous barriers;
• Temporary decline of the benthic community because of lower
oxygen and chemical changes (recovery is rapid once the barrier is
removed [Ussery et al. 1997]);
• Their non-selectivity — they usually kill all plants over which they are
applied; and finally,
• Market stability of the barrier materials — many types are not on the
market more than 5 to 10 years.
Guidelines for successfully using benthic barriers:
• Porous barriers will be subject to less billowing, but will allow settling
plant fragments to root and grow, making annual maintenance
essential.
• Solid barriers will generally prevent rooting if there's no sediment on
them, but will billow after enough gases accumulate; venting and strong
anchoring are essential in most cases.
• Plants under the barrier will usually die completely after about a
month, with solid barriers more effective than porous ones in killing
the whole plant; if they're strong enough, barriers can then be moved
to a new location. However, solid barriers prevent recolonization and
thus might be best kept in place.
• Installation may be difficult to accomplish over dense plant growth; a
winter drawdown might provide the opportunity. Late spring
application also works, however, despite the presence of plants at that
time. Barriers applied in early May have been removed in mid-June
with no substantial plant growth through the summer (Wagner, 1991).
• Scuba divers normally apply the covers in deeper water, greatly
increasing labor costs.
• Bottom barriers will usually accumulate sediment, which allows plant
fragments to root. Barriers must then be cleaned, either in-place
(which is very labor-intensive) or by removing them.
Despite application and maintenance issues, benthic barriers are very effec-
tive. In northern waters, benthic barriers can control milfoil locally (Engel, 1984;
Perkins et al. 1980; Helsel et al. 1996), and at the same time create more edge
habitat where plants grow densely.
267
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Managing Lakes and Reservoirs
As an example, benthic barriers have been used at Lake George since 1986
(Eichler et al. 1995). Plastic sheets initially installed over three acres of milfoil in
two areas controlled milfoil there for about three years. But by 1990, milfoil had
rooted in the sediment, covering portions of the barrier.
At that time, a fine mesh material and a solid sheet were installed at eight
sites. Both succeeded, although when left in place without annual maintenance,
recolonization was far greater on the mesh than on the solid sheet.
Both native species and milfoil recolonized areas of Lake George where
benthic barriers had been removed (Eichler et al. 1995), but milfoil did not domi-
nate for at least two growing seasons. Plant cover was sparse for at least the first
month after barrier removal and typically did not exceed 74 percent after two
growing seasons, providing ample opportunity for milfoil invasion.
Similar plant recolonization occurred in two swimming areas in Great Pond,
Massachusetts (Wagner, 1991) where barriers were applied to improve swim-
ming safety (not control invasive plants). In one swimming area, a plant commu-
nity nearly identical to the original assemblage returned within one to two years
after barrier removal. Regrowth in the second area was kept to a minimum by
foot traffic; the area had been considered unusable before treatment.
Sediment removal was described in some detail in the section on algal control,
but it also works as a plant control technique in two principal ways:
• Limiting light (and growth) by increasing water depth; or
• Removing enough "soft" sediment (muck, clay, silt, and fine sand) to
reveal a less hospitable substrate (typically rock, gravel, or coarse
sand).
An exception is suction dredging, used mostly to remove specific whole
plants and their seeds. Suction dredging might be considered a form of harvesting,
however, as plants are extracted from the bottom by scuba divers operating the
suction dredge; sediment is often returned to the lake.
The amount of sediment removed, and hence, the greater depth and light
limitation are critical to long-term control of rooted, submerged plants. There
appears to be a direct relation between water transparency, as determined with a
Secchi disk, and the maximum depth of colonization (MDC) by macrophytes.
Canfield et al. (1985) provided equations to estimate MDC in Florida and Wis-
consin from Secchi disk measurements:
STATE
EQUATION
Florida log MDC = 0.42 x (log SD) + 0.41
Wisconsin log MDC = 0.79 x (log SD) + 0.25
where SD = Secchi depth in meters
For a Florida lake with a Secchi disk transparency of about 6 feet (1.8 me-
ters), we would expect some submergent plants in 11 feet (3.4 meters) of water
and more plants in progressively shallower water. A great deal of sediment (cal-
culated from a bathymetric map) might have to be removed to create large areas
of the lake with depths of 11 feet or more.
These equations also indicate that actions that greatly improve water clarity,
such as erosion control or phosphorus inactivation, may encourage plant growth
268
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CHAPTER 7: Alonagement Techniques Within the Lake or Reservoir
and distribution, increasing the depth dredging must go to limit light. Partial
deepening may limit the amount of vegetation that reaches the surface, but may
also favor species that tolerate low light — particularly non-native, nuisance spe-
cies such as hydrilla and milfoil.
If the soft sediment supporting rooted plants is not very thick, it may be
possible to remove it and expose rock ledge or cobble so as to prevent rooted
plant growth. But such circumstances are rare; either the sediments grade slowly
into coarser materials, or not all fine sediments can be removed from around the
rock. Consequently, some regrowth is to be expected where light penetrates to
the bottom. Successful dredging may keep this regrowth to only 25 percent of
the pre-dredging coverage, without domination by recently invading species.
Remember, you can — and should — expect some rooted plant regrowth; it
is indeed desirable for proper ecological function of the lake as a habitat and for
processing of future pollutant inputs.
If you're dredging to control rooted plants — and your budget won't let you
remove all the soft sediment — then dredge to the desired depth or substrate in
part of the lake, rather than trying to remove some sediment throughout the lake.
Dredging to control rooted plants has had mixed results. As with dredging
for algal control, failures are invariably linked to incomplete pre-dredging assess-
ment and planning.
• Control through light limitation appears more successful than limiting
the substrate, largely because it is so difficult to remove all soft
sediment from shallow areas.
• Dry dredging projects appear to remove soft sediments more
thoroughly, mainly because equipment operators can visually observe
the results of dredging as it takes place.
• Hydraulic dredging in areas with dense weed beds can frequently clog
the pipeline to the slurry discharge area, suggesting that temporary
plant control (most often herbicides or harvesting) may have to
precede hydraulic dredging.
Limiting Light with Dyes and Surface Covers
The same dyes are used to control rooted plants as are used for algal control
(see previous discussion). Dyes limit light penetration and thus restrict the depth
at which rooted plants can grow, although they have little effect in shallow water
(< 4 ft deep).
Dyes favor species tolerant of low light or with enough food reserves to
support an extended growth period (during which a stem could reach the lighted
zone). In lakes with high transparency but moderate depth and ample soft sedi-
ment, dyes may provide open water where little would otherwise exist.
Treatment must be repeated as the dye flushes out of the system. Dyes are
typically permitted under the same process as herbicides, despite their radically
different mode of action.
Although they could interfere with recreation, surface covers can be a
useful and inexpensive alternative to traditional methods of weed control in
small areas such as docks and beaches. They can be timed to produce results so
as to affect neither summer recreation uses nor overall system ecology.
.
If you're dredging to
control rooted plants —
and your budget won't
let you remove all the
soft sediment — then
dredge to the desired
depth or substrate in
part of the lake, rather
than trying to remove
some sediment through-
out the lake.
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Managing Lakes and Reservoirs
Polyethylene sheets floated on the lake surface were used by Mayhew and
Runkel (1962) to shade weeds. They found that two to three weeks of cover
eliminated all species of pondweeds (Potamogeton spp.) for the summer if the
sheets were applied in spring before plants grew to maturity. Coontail was also
controlled, but the generally desirable macroalga Chara was not.
Mechanical Removal
Mechanical management of aquatic plants is not much different from managing
terrestrial plants, except for the complications imposed by the water. Indeed, me-
chanical weed control techniques (Table 7-5) can be thought of as:
• Mowing the lawn (cutting or harvesting);
• Weeding the garden (hand pulling); or
• Tilling the soil (rototilling or hydroraking).
v Hand pulling is exactly what it sounds like; a snorkeler or diver sur-
veys an area and pulls out individual unwanted plants. This is a highly se-
lective technique, very labor intensive — and obviously not designed for
large-scale, dense beds.
But hand pulling will help keep out invasive species that have not yet
become established. Hand pulling can also effectively address non-
dominant undesirable species in mixed assemblages, or small patches of
plants.
Hand harvesting records for Eurasian watermilfoil in Lake George in
New York for 1989-91 (Darrin Freshw. lnst.1991) reveal the following:
• First-time harvest averaged 90 plants per person-hour.
• Second-time harvest (the same sites revisited the next year)
averaged 41 plants per person-hour.
• Except for substantial regrowth at one site, regrowth the year
after initial harvest was 20 to 40 percent of the initial density.
• Regrowth two years after initial harvest averaged less than 10
percent of the initial density.
• Although plant density and total harvest decline with successive
harvesting, effort declines more slowly; harvest time per plant
increases largely because of search time.
• Actual harvesting effort at 12 sites was 169 hours for first-time
harvest and 90 hours for second-time harvest.
Various tools can augment hand pulling, including a wide assortment of
rakes, cutting tools, water jetting devices, nets, and other collection devices.
Read McComas (1993) for an extensive and enjoyable review of options.
Suction dredging can also augment hand pulling, increasing the pulling
rate since the diver/snorkeler does not have to carry pulled plants to a
disposal point.
^ Cutting is also exactly what it appears to be. A blade of some kind sev-
ers the actively growing stem (and possibly much more) from its roots.
Regrowth is expected, but some species regrow so rapidly that the bene-
270
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
fits of cutting are negated in only a week or two. If the plant can be cut
close enough to the bottom, or repeatedly, it will sometimes die, but this
is more the exception than the rule.
Cutting is defined here as an operation that does not involve collect-
ing the plants once they are cut, so large-scale cutting operations may af-
fect dissolved oxygen.
Handheld cutters and mechanized barges (like those used with har-
vesting) cut the plants but don't collect them. Recently, barges have been
developed to grind the plants to minimize their viability after cutting and
processing. Dissolved oxygen may be affected as the plant biomass decays,
much as with most herbicide treatments.
Harvesting can collect weeds using a number of methods:
• Hand-held nets;
• Small boats towed by the person collecting the weeds;
• Small boat-mounted cutting tools that cut biomass and haul it
into the boat for eventual disposal on land; or
• Larger commercial machines with numerous blades, a conveyor
system, and a substantial storage area for cut plants.
Offloading accessories allow easy transfer of weeds from the har-
vester to trucks that haul the weeds to a composting area.
The choice of equipment is really one of scale: is your weed problem
massive or confined to a small, nearshore area? Where weeds are a domi-
nant, recurring problem, some lake associations choose to purchase and
operate harvesters built to their specifications, while others prefer to
contract for harvesting services.
Cutting rates for commercial harvesters tend to range from about
0.2 to 0.6 acres per hour, depending on machine size and operator ability.
Even at the highest conceivable rate, harvesting is a slow process that may
leave some lake users dissatisfied with progress in controlling aquatic
plants.
Weed disposal is not usually a problem, in part because lakeshore
residents and farmers often will use the weeds as mulch and fertilizer.
Also, since aquatic plants are more than 90 percent water, their dry bulk is
comparatively small. Odors can sometimes be an issue.
Key issues in choosing a harvester include depth of operation, vol-
ume and weight of plants to be stored, reliability, and ease of maintenance,
along with a host of details regarding the hydraulic system and other me-
chanical design features.
RototiHing and cultivation equipment are newer procedures
with a limited track record (Newroth and Soar, 1986). A rototiller is a
barge-like machine with a hydraulically operated tillage device that can be
lowered 10 to 12 feet to tear out roots. If the water level in the lake can
be drawn down, cultivation equipment pulled behind tractors on firm
sediments can remove 90 percent of the roots.
These techniques may significantly affect non-target organisms and
water quality, but can reduce severe weed infestations.
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Managing Lakes and Reservoirs
Hydrorake: A floating
backhoe, usually outfitted
with a York rake that looks
like a farm implement for
tilling or moving silage.
r Hydroraking can be thought of as using a floating backhoe, usually
outfitted with a York rake that looks like a farm implement for tilling or
moving silage. The tines of the rake attachment move through the sedi-
ment, ripping out thick root masses and associated sediment and debris. A
hydrorake can be a very effective tool for removing submerged stumps,
water lily root masses, or floating islands. This is not a delicate operation,
however, and will create substantial turbidity and plant fragments. Hydro-
raking in combination with a harvester can remove most forms of vegeta-
tion found in lakes.
Most mechanical plant removal operations produce at least tempo-
rary relief from nuisance plants and remove organic matter and nutrients
without adding potentially damaging substances. But, be aware that with-
out proper planning you might face at least two problems:
• Plants often regrow very rapidly (days or weeks), especially in
southern waters where midsummer growth rates of water
hyacinth can exceed the rate at which they can be harvested; and
• Harvesting may reduce plant diversity and leave areas open for
colonization by invasive species.
A bay of LaDue Reservoir (Geauga County, Ohio) was harvested in
July 1982 by the traditional method: the operator simply mowed the weed
bed like a residential lawn. Stumps of Eurasian watermilfoil plants about
0.5 to 3 inches in height were left; they completely regrew in 21 days.
In contrast, the slower method of lowering the cutter blade about I
inch into the soft lake mud to tear out roots controlled milfoil for the en-
tire season (Conyers and Cooke, 1983). This method has demonstrated a
carry-over effect (less growth in the subsequent year), especially if the area
had multiple harvests in one season. But this cutting technique won't work
in stiff sediments or in water so deep the cutter bar cannot reach the mud.
Some weed species are more sensitive to harvesting than others.
Nicholson (1981) has suggested that harvesting actually spread milfoil in
Chautauqua Lake, New York, because the harvester distributed fragments
of plants from which new growths could begin. On the other hand, milfoil
has become dominant in many northeastern lakes without harvesting pro-
grams in less than five years after initial appearance (Wagner, pers. obs.)
Timely harvesting of species that re-seed can eventually limit the ex-
tent of those species, but seeds may remain viable in the sediment for many
years. For example, extensive harvest of water chestnut in impounded sec-
tions of Boston's Charles River in 1996 did not seem to affect plant growth
the following year. Harvesting was repeated in 1997, and 1998 growths de-
clined substantially. Sequentially less harvesting has been necessary in 1999
and 2000, but growth from seeds continues (Smith, pers. comm.)
Few data validate the actual restorative effects of harvesting as it re-
lates to controlling nutrients in the water column. If nutrient inputs are
moderate and weed density is high, intense harvesting could remove as
much as 40 to 60 percent of net annual phosphorus loading — a signifi-
cant nutrient removal in many cases. On the other hand, harvesting itself
can increase phosphorus concentration in the water either by disturbing
the sediments or by making it easier for sediments to release phosphorus.
In almost any event, nutrients in the sediment remain adequate to support
dense plant growths.
272
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Water Level Control
Historically, water level drawdown has been used in waterfowl impoundments
and wetlands for a year or more, including the growing season, to improve the
quality of waterfowl breeding and feeding habitat (Kadlec, 1962). It is also a com-
mon fishery management method.
Until a few decades ago, recreational lakes were lowered primarily to con-
trol flooding and allow access for cleanups and repairs; macrophyte control was a
side benefit. While this technique is not effective on all submergent species, it
does reduce some of the chief nuisance species, particularly those that rely on
vegetative propagules for overwintering and growing (Cooke et al. 1993a). If a
drawdown capability exists at your lake, lowering the water level is an inexpen-
sive way to control some macrophytes. It will also give you the opportunity to
maintain shorelines or remove nutrient-rich sediments.
The ability to control a lake's water level is affected by the area's precipita-
tion pattern, system hydrology, lake morphometry, and the outlet structure. The
base elevation of the outlet or associated subsurface pipe(s) will usually set the
maximum drawdown level, while the outlet's capacity to pass water and the pat-
tern of water inflow to the lake will determine if that base elevation can be
achieved and maintained. In some cases, sedimentation of an outlet channel or
other obstructions may control the maximum drawdown level.
Several factors affect how well drawdown works to control plants:
• While drying of plants during drawdowns in southern areas may
provide some control, the additional impact of freezing is substantial,
making drawdown a more effective strategy for northern lakes during
late fall and winter.
• A mild winter or one with early and continuing snow may not provide
the necessary level of drying and freezing.
• High levels of groundwater seepage into the lake may also negate the
desired effects by keeping the area moist and unfrozen.
• Extensive seed beds may quickly re-establish undesirable plants.
• Recolonization from nearby areas may be rapid.
• And finally, the response of macrophytes to drawdown is quite
variable (Table 7-6).
Drawdown has a long and largely successful history, even if not always in-
tended to control plants (Dunst et al. !974;Wlosinski and Koljord, 1996). The ini-
tial winter drawdown of Candlewood Lake in Connecticut (Siver et al. 1986)
reduced nuisance species by as much as 90 percent. Drawdowns in Wisconsin
lakes have decreased plant coverage and biomass by 40 to 92 percent (Dunst et
al. 1974). In one Wisconsin case, Beard (1973) reported that winter drawdown of
Murphy Flowage opened 64 of 75 acres to recreation and improved fishing.
The effect of drawdown is not always predictable or desirable, however. Re-
ductions in plant biomass of 44 to 57 percent were observed in Blue Lake in
Oregon (Geiger, 1983) following drawdown, but certain nuisance species actually
increased and herbicides were eventually applied to regain control. Drawdown of
Lake Bomoseen in Vermont (Vt. Agency Nat. Resour. 1990) caused a major re-
duction in many species, many of which were not targeted.
.
i,
a drawdown
capability exists at your i
lake, lowering the water;
level is art inexpensive ;
way to control some
macrophytes.
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Managing Lakes and Reservoirs
Table 7-6.— Anticipated responses of some wetland and aquatic plants to winter water-level drawdown.
' ' ' ' ' ' ' ' ' " ' '
Acorus calamus (sweet flag)
Allernanlhera philoxeroides (alligator weed)
Asclepias incarnata (swamp milkweed)
Brasen/a schreberi (watershield)
Cabomba carolinlana (fanwort)
Cephalanthus occidentals (buttonbush)
Ceralophyllum demersum (coontail)
Egeria densa (Brazilian Elodea)
Elchhornia crassipes (water hyacinth)
Eleocharis acicularis (needle spikerush)
Elodea canadensis (waterweed)
Glyceria borealis (mannagrass)
Hydrilla vertlcilata (hydrilla)
Leersia oryzoldes (rice cutgrass)
Myrlca gale (sweetgale)
Myriophyllum spp. (milfoil)
No/as flexilis (bushy pondweed)
No/as guadalupensis (southern naiad)
Nuphar spp. (yellow water lily)
Nymphaea odorata /water lily)
Polygonum amphibium (water smartweed)
Polygonum coccineum (smartweed)
Potamogeton epihydrus (leafy pondweed)
Potamogeton robbinsii (Rabbins' pondweed)
Potentilla palusfris (marsh cinquefoil)
Scirpus americanus (three square rush)
Scirpus cyperinus (wooly grass)
Scirpus validus (great bulrush)
Siom suave (water parsnip)
Typha latifolla (common cattail)
Zizania aquatic (wild rice)
CHANGE IN RELATIVE ABUNDANCE
INCREASE
E
E
E
S
S
E
S
E
S
E
S
E
E
E
E
E
NO CHANGE
E/S
S
S
E
E/S
E
E
DECREASE
E
S
S
S
S
S
S
S
S
E/S
S
S
E/S
E=emergent growth form; S=submergent growth form; E/S=emergent and submergent forms
Source: Cooke et al. 1993a.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Reviewing drawdown effectiveness in a variety of lakes, Nichols and Shaw
(1983) noted its species-specific effects, with both benefits and drawbacks. So, be-
fore you conduct a drawdown, do a thorough system-specific review of likely im-
pacts.
Desirable side effects associated with drawdowns:
• The opportunity to clean up the shoreline, repair previous erosion
damage, repair docks and retaining walls, search for septic system
breakout, and physically improve fish spawning areas (Nichols and
Shaw, 1983; Cooke et al. 1993a; Wis. Dep. Nat. Resour. 1989).
• The attendant concentration of forage fish and game fish in the same
areas (Cooke et al. 1993a), although not all fishery professionals agree.
« Benefits for furbearers, since drawdowns usually help emergent
shoreline vegetation (Wis. Dep. Nat. Resour. 1989), although not all
wildlife biologists agree.
« The consolidation of loose sediments and sloughing of soft sediment
deposits into deeper water, perceived as a benefit by shoreline
homeowners (Cooke et al. 1993a; Wis. Dep. Nat. Resour. 1989).
• Encouragement of some desirable plants.
Undesirable possible side effects of drawdown:
• Loss or reduction of desirable plant species.
• Facilitation of invasion by drawdown-resistant undesirable plants;
either seeds or expanding shoreline vegetation can recolonize.
Cattails and rushes are the most commonly expanding fringe species
(Nichols and Shaw, 1983; Wis. Dep. Nat. Resour. 1989). Drawdowns to
control nuisance submergent vegetation are usually recommended for
alternate years to every third year to prevent domination by resistant
plant species (Cooke et al. I993a).
• Reduced attractiveness to waterfowl (considered an advantage by
some).
• Possible fishkills if oxygen demand exceeds reaeration during a
prolonged drawdown.
• Changes in fish and invertebrate habitat.
• Mortality among hibernating reptiles and amphibians.
• Impacts to connected wetlands.
• Shoreline erosion during drawdown.
• Loss of aesthetic appeal during drawdown.
• More frequent algal blooms after refill in some cases.
• Reduction in water supply: processing or cooling water intakes may
be exposed, reducing or eliminating intake capacity. The water level in
wells with hydraulic connections to the lake will decline, as may the
yield, along with changes in water quality and pumping difficulties.
• Recreational problems during the drawdown: swimming areas will
shrink and beach areas will enlarge during a drawdown. Boating may
be restricted both by available lake area and by access to the lake.
Again, winter drawdown will avoid most of these disadvantages,
275
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Managing Lakes and Reservoirs
illing nuisance
aquatic weeds with
chemicals is probably
the oldest — and still
the most widely used —
ijpntrol method. Butjew
aspects of plant control
*^ I! ;"""* ; " " 'a—!"'™* »
breed more controversy
than chemical control by
herbicides, which are
types of pesticides.
although lack of control over winter water levels can make ice unsafe
for fishing or skating.
• Outlet structures, docks, and retaining walls may be damaged by
freeze/thaw processes during overwinter drawdowns if the water
level is not lowered beyond all contact with structures.
• Downstream flow impacts (Nichols and Shaw, 1983; Cooke et al.
I993a):flood storage and the downstream flow will both increase
during a drawdown, but once the drawdown level is reached, the
downstream flow should stabilize. The key to managing downstream
impacts is to minimize erosion and keep flows within an acceptable
natural range.
• The time it takes to refill a lake after drawdown: enough water must
enter the lake to refill it in an appropriate timeframe while
maintaining an acceptable downstream flow. In northern lakes, early
spring is the best time for refill, with the melting snowpack and rainfall
on frozen ground yielding maximum runoff.
Carefully planned fluctuations in water level can help check nuisance macro-
phytes and periodically rejuvenate wetland diversity. Planned disturbance is al-
ways a threshold phenomenon; a little is beneficial, too much leads to overall
ecosystem decline. The depth, duration, tinning, and frequency of the drawdown
are therefore critical elements in devising the most beneficial program.
Herbicides
Killing nuisance aquatic weeds with chemicals is probably the oldest — and still
the most widely used — control method. But few aspects of plant control breed
more controversy than chemical control by herbicides, which are types of pesti-
cides. Part of the problem stems from pesticides that have enjoyed widespread
use and then been linked to environmental or human health problems, and subse-
quently banned. Some left long-term environmental contamination and toxicity
problems behind. Books such as Silent Spring (Carson, 1962) and Our Stolen Future
(Colburn et al. 1997) have raised both public consciousness and wariness of
chemicals in the environment.
Current pesticide registration procedures are far more rigorous than in the
past. While no pesticide is considered unequivocally "safe," federal pesticide
regulation is based on the premise that when the chemical is used according to
label instructions, it will not cause unreasonable human health or environmental
effects. Federal regulations do not restrict swimming in water treated with any of
the currently registered aquatic herbicies, although many applicators recommend
that you should avoid contact with treated water for at least a day. Some states
impose more restrictions.
Only six active ingredients are widely used in aquatic herbicides in the U.S
today, with one additional ingredient awaiting approval. Westerdahl and Getsinger
(I988a,b) provide a detailed discussion of herbicide properties and effectiveness
on specific plants. Aquatic and terrestrial versions exist under various trade
names, causing some confusion.
^ Copper (see the algal control section) is not a primary herbicide for
rooted aquatic plants, but is sometimes part of a broad spectrum formu-
lation intended to reduce the biomass of an entire plant assemblage.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Copper formulations are also used on certain plants where use restric-
tions preclude the use of other herbicides. Copper concentrations should
not exceed I mg/L in the treated waters.
Endothall is a contact herbicide, attacking a wide range of plants at the
immediate point of contact. It is sold in several formulations: liquid
(Aquathol K), granular dipotassium salt (Aquathol), and the di (N,
N-dimethyl-alkylanine) salt (Hydrothol) in liquid and granular forms. Effec-
tiveness can range from weeks to months. Most endothall compounds
break down readily and do not remain in the aquatic environment.
Endothall acts quickly on susceptible plants, but does not kill roots
with which it cannot come into contact, so many plants recover rapidly.
Quickly dying plants can deplete oxygen if decomposition exceeds re-
aeration; successive partial treatments will minimize this effect. Toxicity to
invertebrates, fish, or humans is not expected to be a problem at the rec-
ommended dose, yet it is not used in drinking water supplies. Depending
on the formulation, concentrations in treated waters should be limited to
I to 5 mg/L.
Diquat, like endothall, is a fast-acting contact herbicide, producing re-
sults within two weeks. Although diquat has exhibited toxicity to aquatic
fauna in the laboratory, toxicity has not been clearly documented in the
field. Domestic water use is normally restricted for seven days, and this
herbicide is not used in drinking water supplies. Some species have re-
grown rapidly (often within the same year) after treatment with diquat,
while others have been controlled longer. Concentrations in treated wa-
ter should not exceed 2 mg/L
Glyphosate is primarily a contact herbicide, but some uptake by plants
has been observed. It is effective against most emergent or floating-leaved
plant species, but not against most submergents. Rainfall shortly after treat-
ment can negate its effectiveness, as does its ready adsorption to
particulates in the water or to sediments. At recommended doses, it is rel-
atively non-toxic to aquatic fauna, and degrades readily into non-toxic com-
ponents in the aquatic environment. There is no maximum concentration
for treated water, but a dose of 0.2 mg/L is usually recommended.
2f4-Df the active ingredient in a variety of commercial herbicide prod-
ucts, has been in use for over 30 years despite claims of undesirable envi-
ronmental and human health effects. This is a systemic herbicide; it is
absorbed by roots, leaves, and shoots and disrupts cell division through-
out the plant. Vegetative propagules such as winter buds, if not connected
to the circulatory system of the plant at the time of treatment, are gener-
ally unaffected and can grow into new plants. It is therefore important to
treat plants early in the season, after growth has become active but before
such propagules form.
2,4-D is sold in liquid or granular forms as sodium and potassium
salts, as ammonia or amine salts, and as an ester. Doses of 50 to ISO
pounds per acre are usual for submersed weeds, most often of the di-
methylamine salt or butoxyethanolester (BEE) in granular form. This her-
bicide is particularly effective against Eurasian watermilfoil (granular BEE
277
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Managing Lakes and Reservoirs
applied to roots early in the season) and as a foliage spray against water
hyacinth. 2,4-D lasts only a short time in the water but can be detected in
the mud for months.
Properly applied, granular 2,4-D generally controls nuisance
macrophytes such as Eurasian watermilfoil with only sublethal damage to
many native species (Helsel et al. 1996). The native community has also re-
covered from seed. 2,4-D has variable toxicity to fish, depending upon for-
mulation and species. The 2,4-D label does not permit use of this
herbicide in water used for drinking or other domestic purposes, or for
irrigation or watering livestock. Concentrations in treated water should
not exceed 0.1 mg/L.
Plastic curtains have been used to contain waters treated with 2,4-D,
and only 2 to 6 percent of the herbicide escaped outside the target area
(Helsel et al. 1996). This approach marks the beginning of a new wave of
more selective and integrated rooted plant management.
' Fluridone is a systemic herbicide introduced in 1979 (Arnold, 1979). It
has been widely used since the mid-1980s, although some states have
been slow to approve it. Fluridone currently comes in two formulations,
an aqueous solution and a slow release pellet.
This chemical inhibits carotene synthesis, which in turn exposes the
chlorophyll to photodegradation. The entire plant will die with prolonged
exposure to enough fluridone. Some plants, including Eurasian watermil-
foil, are more sensitive to fluridone than others, allowing selective control
at low dosages.
For susceptible plants, lethal effects take several weeks to several
months, with 30 to 90 days given as the range of time for dieoff after
treatment. Fluridone concentrations should be maintained in the lethal
range for about six weeks. This may be difficult where there is substantial
water exchange, but the slow dieoff rate minimizes the risk of oxygen de-
pletion.
Fluridone has low toxicity to invertebrates, fish, other aquatic wildlife,
and humans, and is not known to be a carcinogen, oncogen, mutagen, or
teratogen. Substantial bioaccumulation has been noted in certain plant
species, but not in animals. EPA has designated a tolerance level of 0.5 ppm
(mg/L or mg/kg) for fluridone residues or those of its degradation prod-
ucts in fish or crayfish, and 0.15 ppm in potable water supplies; state re-
strictions may be lower.
If the recommended 40 days of contact time can be achieved, the liq-
uid formulation of fluridone applied in a single treatment can be very ef-
fective. Where dilution may occur, the slow release pellet is generally used,
or sequential liquid treatments are performed.
Gradual release of fluridone, which is 5 percent of pellet content, can
yield a relatively stable concentration. But pellets have been less effective
in highly organic, loose sediments than over sandy or firm substrates
(Haller, pers. comm.), largely because of a phenomenon termed "plugging"
that prevents the active ingredient from being released from the pellet.
Multiple sequential treatments with the liquid formulation are more effec-
tive in areas with extremely soft sediments and significant flushing.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Eurasian watermilfoil has been controlled for several years or more
without significant impact on non-target species at doses close to 0.01
mg/L (Smith and Pullman, 1997). Recently, applicators have been trying
even lower doses (0.006 mg/L) with some success; most native species are
minimally affected, but control of milfoil has been erratic and generally
short-lived (< 2 years).
Also of interest is the first ever sequestered treatment with fluridone
in 2000, whereby curtains were used to seal off target areas from the rest
of the lake (McNabb, pers. comm.). Escape was low, dilution was limited,
and milfoil appears to have been eliminated without impact outside the
barrier.
^ Triclopyr is currently experimental for aquatic habitats. It is highly selec-
tive and effective against Eurasian watermilfoil at a dose of I to 2.5 mg/L. It
seems to have little or no effect on valued native species such as most
monocotyledonous naiads and pondweeds (Netherland and Getsinger,
1993). It prevents synthesis of plant-specific enzymes, thereby disrupting
growth processes. This herbicide is most effective when applied during the
active growth phase of young plants.
Triclopyr is not known to be a carcinogen, oncogen, mutagen, or tera-
togen, and tested animals have been lethally affected only at concentra-
tions over 100 times the recommended dosage rate. The experimental
label calls for concentrations in potable water of no more than 0.5 mg/L,
suggesting that care must be taken to allow sufficient dilution between the
point of application and potable water intakes.
A herbicide treatment can be an effective short-term management proce-
dure to rapidly reduce vegetation for periods of weeks to months. As many as
five years of control have been gained with fluridone or 2,4-D. Herbicide treat-
ments are still the best way to open the vast acreages of water infested with the
exotic water hyacinth (Eichhornia crassipes) in Florida and other southeastern
states (Shireman et al. 1982). This is a case in which chemical management be-
comes necessary until some other more long-term control, such as plant-eating
insects, can be established.
Using herbicides to get a major plant nuisance under control is a valid ele-
ment of long-term management when followed by supplementary methods for
keeping such plants under control. Otherwise, herbicide treatments become sim-
ply cosmetic maintenance; such techniques tend to have poor cost-benefit ratios
over the long term.
Lake managers who choose herbicides must exercise all proper precautions.
As shown in Table 7-7, effectiveness of a given herbicide varies by plant species
and therefore the nuisance plants must be carefully identified. Users should fol-
low the herbicide label directions, use only a herbicide registered by EPA for
aquatic use, wear protective gear during application, and protect desirable plants.
Most states require applicators to be licensed and insured.
Important questions to be answered before adopting a management pro-
gram involving herbicides include:
• What are the acreage and volume of the area(s) to be treated?
Proper dosage is based on this information.
• What plant species are to be controlled? This will determine the
herbicide and dose to be used.
'sers should follow
the herbicide label
directions, use only a
herbicide registered by
iPA for aquatic use,
wear protective gear
during application, and
protect desirable plants.
Most states require
applicators to be
licensed and insured.
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Managing Lakes and Reservoirs
1 Table 7-7.— Susceptibility of common aquatic plant species to herbicides.
CONTROLLED BY HERBICIDE APPLICATION
DIQUAT
ENDOTHAL
EMERGENT SPECIES
Alternanthera philoxeroides (alligator weed)
Dianlhera americana (water willow)
G/ycerio borealis (mannagrass)
Phragmites spp. (reed grass)
Sagittaria spp. (arrowhead)
Scirpus spp. (bulrush)
Typha spp. (cattail)
Y
N
N
Y
N
N
N
N
2,4-D
••• •! *- , , ' '.' ' :'•-'•• '
''ff&W *'>-> >'••*•> ••"('
Y
Y
N
Y
Y
Y
GLYPHOSAT
E
Y
Y
Y
Y
FLURIDONE
'"RT""I ""'r^ ?:*;;>
Y
Y
Y
Y
FLOATING SPECIES . .".' /' '^''''*V'"/' •':•'';" ' '.^'.'I'- ~"""T " '"..''.'" :' '2',:'^
Brasenia schreberi (watershield)
Eichhornia crassipes (water hyacinth)
Lemna spp. (duckweed)
Nelumbo lutea (American lotus)
Nup/)orspp. (yellow water lily)
Nymphaea spp. (white water lily)
Wolfia spp. (watermeal)
N
Y
Y
N
N
N
Y
Y
N
N
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
N
1 • 1
N
Y
Y
Y
Y
SUBMERGED SPECIES
Ceratophyllum demersum (coontail)
Cabomba caroliniana (fanwort)
C/iaro spp. (stonewort)
Elodea canadensis (waterweed)
Hydrilla verticillata (hydrilla)
Myriophyllum spicatum (Eurasian wafermilfoil)
No/as Hexills (bushy pondweed)
No/as guadalupensis (southern naiad)
Potamogeton amplifolius (largeleaf pondweed)
Potamogeton crispus (curlyleaf pondweed)
Potamogeton diversifolius (waterthread)
Polamogeton natans (floating leaf pondweed)
Potamogeton pectinatus (sago pondweed)
Potamogeton illinoensis (Illinois pondweed)
Ranunculus spp. (buttercup)
Y
N
N
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
N
N
Y
N
N
N
N
N
Y
N
Y
N
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y :
Y
Y
Adapted from Nichols, 1986. Y=Yes, N=No, blank=uncertain
Note: Chora spp. (stonewort) can be controlled with copper, which also enhances the performance of Diquat on Eichhornia crassipes (water
hyacinth).
280
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• What will the long-term costs of this decision be? Most herbicides
must be reapplied annually, in some cases twice per growing season.
• How is this water body used? Many herbicides have restrictions of a
day to two weeks on certain water uses following application.
• Is the applicator trained, experienced, licensed, and insured, and has a
permit been obtained from the appropriate regulatory agency? All are
desirable (and sometimes necessary) prior to treatment.
Shireman et al. (1982) caution that the following lake characteristics often
produce undesirable water quality changes after treatment with a herbicide for
weed control:
• High water temperature,
• High plant biomass to be controlled,
• Shallow, nutrient-rich water,
• High percentage of lake area treated,
• Closed or non-flowing system.
Competent applicators will be cautious in treating a lake with these condi-
tions.
Biological Introductions
Biocontrol organisms may eventually help us achieve lasting control of nuisance
aquatic vegetation. Biological control harnesses the power of biological interac-
tions to manage plants; however, it suffers from the ecological drawback that in
predator-prey relationships it is rare for the predator to completely eliminate the
prey. Consequently, population cycles for both predator and prey are likely. Hu-
mans may find the magnitude of these cycles in plant populations unacceptable, so
other techniques may have to be combined with biocontrols to achieve lasting,
predictable results.
Biological controls include herbivorous fish such as the grass carp
(Ctenopharyngidon idella), insects such as the aquatic milfoil weevil (Euhrychiopsis
lecontei), and experimental fungal pathogens. Aside from grazing and parasitism,
maintaining a healthy native community also works to limit invasive species
through competition.
T Herbivorous fish such as the non-native grass carp (imported
around 1962) voraciously consume many weeds. The grass carp grows
very rapidly (about 6 pounds per year maximum; Smith and Shireman,
1983). This combination of broad diet and high growth rate can control
or even eradicate plants within several seasons.
Like people, grass carp prefer certain food. They generally avoid alli-
gatorweed, water hyacinth, cattails, spatterdock, and water lily — choosing
instead species such as waterweed, pondweeds, and hydrilla. Fish will graze
selectively on the preferred plant species while less preferred species, in-
cluding milfoil, may increase. Overstocking, on the other hand, may elimi-
nate all plants, contrary to the ecological axiom of encouraging population
cycles. Feeding preferences are listed in Cooke and Kennedy (1989).
.
B,
'
iological control
harnesses the power of
biological interactions
to manage plants; how-
ever, it suffers from the
ecological drawback
that in predator-prey
relationships it is rare
for the predator to
completely eliminate
the prey.
281
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Managing Lakes and Reservoirs
Vising grass carp will
arobably drastically
ill i ilp-
:hange the ecology of a
ake. Stocked to reduce
slants, grass carp
ypically cause a shift
oward algal blooms
and more turbidity —
which then becomes a
self-sustaining lake
Condition.
Not all states permit the introduction of grass carp, so consult your
state fishery agency before you decide to use them. Critical controls in-
clude:
• Restrictions on the ability of the fish to reproduce (sterile
triploid fish vs. reproductive diploid fish); and
• Inlet and/or outlet controls to prevent emigration.
Stocking rates are based primarily on qualitative and quantitative
characteristics of the lake, with adjustment by region. Rates of up to 70
fish per acre have been used to remove dense nuisance plant growth,
while rates of only I to 2 fish per acre have been used in lakes with a
lower density of more desirable vegetation.
Stocked fish are normally 10 to 12 inches in length to protect them
from predation. Stocking is typically performed on a 6-year cycle linked to
fish mortality.
Although many lakes (most notably, small ponds) have successfully
used grass carp, the definition of success varies.
• Introduction of 3 to 5 fish per acre into Lake Conway (Florida)
greatly reduced hydrilla, nitella, and pondweeds after two years,
leaving non-targeted water celery (Vallisneria) largely unaffected
'' (Miller and King, 1984). But algal biomass increased, indicating
that fish can affect productivity (see the algal control section of
this chapter).
• In contrast, stocking about 13 fish per acre (30/acre if only
vegetated acres are counted) in Lake Conroe (Texas) eliminated
all submersed plants in under 2 years, increased algal biomass,
and changed the algae to less desirable forms (Maceina et al.
1992).
• In small Lake Parkinson (New Zealand), grass carp eradicated the
invasive, non-native Brazilian elodea (Egeria densa), were
themselves then removed by netting and rotenone poisoning, and
a native flora was naturally re-established from the existing seed
bed (Tanner et al. 1990).
• The grass carp experience at Santee-Cooper (South Carolina) is
an interesting story. Stocking 900,000 triploid carp eliminated all
plants and stopped bass reproduction.
Failure of this technique has generally been a function of fish diet not
matching targeted plant species, inappropriate stocking rates, and lack of pa-
tience (essential with biological techniques) before taking additional action.
Using grass carp will probably drastically change the ecology of a lake.
Stocked to reduce plants, grass carp typically cause a shift toward algal
blooms and more turbidity — which then becomes a self-sustaining lake
condition. Gamefish production will suffer from this condition, which lake
users may find more objectionable than the original plants.
' Non-native insects have historically been used to control rooted
plants. Ten insect species have been imported to the United States under
quarantine and have received U.S. Department of Agriculture approval for
release to U.S. waters. These insects — which include aquatic larvae of
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
moths, beetles, and thrips — have life histories specific to certain host
plants and are therefore confined to the waters of southern states in-
fested with those plants: alligatorweed, hydrilla, water lettuce, and water
hyacinth (Cooke et al. 1993a).
They also appear climate-limited to southern states, their northern
range being Georgia and North Carolina. Because they reproduce more
slowly than their target plants, control takes awhile, although it can be ac-
celerated by using harvesting or herbicides to reduce major plant growth,
with insects concentrated on the remaining plants.
Insects have proven highly effective in controlling alligatorweed and
water hyacinth; for example, Sanders and Theriot (1986) report that since
1974, the water hyacinth weevil (Neochetina eichhorniae) has reduced the
distribution of water hyacinth in Louisiana by 50 percent.
Integrated pest management combines biological, chemical, and me-
chanical controls to maximize effectiveness. Insects are particularly effective
when combined with other plant management techniques. Supplemental
chemical or mechanical controls work best if done in early fall or winter to
minimize interference with the insects.
When a Florida canal section was harvested at the peak of the grow-
ing season, both water hyacinths and weevils severely decreased (Center
and Durden, 1986). Subsequent plant growth was much greater than the
weevil population, greatly delaying control. Another section of the same
canal was sprayed with 2,4-D at the end of the season, allowing plants and
weevils to recover simultaneously and facilitating more rapid control by
the weevil.
In a Florida pond, weevils gradually eliminated water hyacinth in con-
junction with sequential 2,4-D treatments of sections of the pond (Haag,
1986). Chemical treatments were conducted in such a manner as to leave
refuges for the weevil. Alligatorweed later invaded the pond, but was con-
trolled by the alligatorweed flea beetle, Agasicles hygrophila.
Despite these successes, non-native species have a poor track record
for solving biological problems (they seem to create as many problems as
they solve); thus, government agencies tend to prefer alternative controls.
Using native insects in a biomanipulative approach is, however, usually ac-
ceptable.
' Native insects — primarily the larvae of midgeflies, caddisflies, bee-
tles, and moths — appear promising as aquatic plant controls, mainly in
northern states (Cooke et al. I993a). However, in recent years, the
aquatic weevil Euhrychiopsis lecontei has received the most attention.
Native to North America, Euhrychiopsis lecontei is believed to have
been associated with northern watermilfoil (Myriophyllum sibericum), a spe-
cies largely replaced since the 1940s by non-native, Eurasian watermilfoil
(M. spicatum). The weevil is able to switch plant hosts within the milfoil ge-
nus, although to varying degrees and at varying rates depending upon ge-
netic stock and host history (Solarz and Newman, 1996).
Weevils do not use non-milfoil species, but can structurally damage
Eurasian watermilfoiPs growth points (apical meristems) and supports (ba-
sal stems) (Sheldon and O'Bryan, 1996a). Weevils feed on milfoil, lay eggs
on it, and pupate in burrows in the stem.
.
I __ . ;
I ntegrated pest
management combines i
biological/ chemical/ and
mechanical controls to
maximize effectiveness. :
Insects are particularly
effective when combined
with other plant
management techniques.
Supplemental chemical
or mechanical controls
work best if done in
early fall or winter to
minimize interference
with the insects.
283
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Managing Lakes and Reservoirs
Field observations link the weevil to natural milfoil declines in nine
Vermont lakes and several lakes outside that state (no weevils were
intentionally brought into any of these lakes)(Creed, 1998).
Lakewide crashes have not been observed where the weevil has been
introduced into only part of the lake, although local damage has been sub-
stantial; widespread control may require more time. Like the non-native
insects, the native weevil reproduces more slowly than does its host plant,
so for faster results, more weevils must be stocked. Still unknown is why
the weevil was able to naturally overpower the milfoil population in cases
like the Vermont lakes. Longevity of control remains unknown, but classic
predator-prey population cycles are expected.
One to three weevils per stem appear to collapse milfoil plants; thus,
raising the necessary weevils is a major operation. The state of Vermont
devoted considerable resources to rearing weevils over a two-year period,
using them all for just a few targeted sites (Hanson et al. 1995).
Weevils are now marketed commercially as a milfoil control, with a
recommended stocking rate of 3,000 adults per acre. Weevils are usually
released from cages or onto individual stems; early research attached a
stem fragment with a weevil from the lab onto a milfoil plant — a highly
labor-intensive procedure.
Although an integrated milfoil management approach may be able to
use weevils effectively, competing control techniques may affect their per-
formance (Sheldon and O'Bryan, 1996b):
• Harvesting may directly remove weevils and reduce their density
during the growing season.
• Because adults overwinter in debris along the edge of the lake,
techniques such as drawdown, bottom barriers, or sediment
removal can kill them.
• Extension of lawns to the edge of the water and application of
insecticides also threaten these milfoil control agents.
' Plant pathogens remain largely experimental, despite a long history
of research interest. Properties that make them attractive (Freeman,
1977) include:
• High abundance and diversity;
• High host specificity;
• No effects on non-target organisms;
• Ease of dissemination and self-maintenance; and
• Ability to limit host population without eliminating it.
Fungi are the most common plant pathogens, and using them to con-
trol water hyacinth, hydrilla, or Eurasian watermilfoil has been extensively
evaluated (Theriot, 1989; Gunner et al. 1990; Joye, 1990). Although many
problems plague this approach, combining fungal pathogens with herbi-
cides has shown recent promise as an integrated technique (Nelson et al.
1998).
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
' Native plants provide some resistance to non-native invasions. Al-
though invasive nuisance plant species are just what the name implies, the
presence of a healthy, desirable plant community may be able to minimize
or slow infestation rates. Disturbance encourages invasive species, so a
stable plant community should provide a significant defense.
Unfortunately, natural disturbances abound, and almost all common
plant control techniques disturb the environment. Therefore, if native spe-
cies are to regain dominance after a disturbance, they may need help, such
as additional seeding and planting. This is still a highly experimental proce-
dure, but if native species are employed it should be less controversial.
Experiments conducted in Texas (Doyle and Smart, 1995) indicate that
dried seeds added to an exposed area of sediment will rapidly germinate to
cover the previously exposed area. However, if this is not done early enough
in the growing season to allow plants to mature and produce seeds of their
own, annual plants will not return the second growing season.
Transplanting mature growths into exposed areas is a better way to
establish a seed-producing population. Planting cuttings gathered by a har-
vester (Helsel et al. 1996) did not establish native species in areas previ-
ously covered by a benthic barrier in Wisconsin.
In Lake George, New York, where the native plant community is di-
verse and dense, colonization by Eurasian watermilfoil has been much
slower than in many other area lakes (Wagner and Clear, 1996). Although
in some areas the sediment itself may be inhospitable to milfoil, when
milfoil is cleared from an area and a native assemblage restored, milfoil
growth greatly diminishes (Eichler et al. 1995). It would seem that estab-
lishment of desired vegetation is entirely consistent with the primary plant
management axiom: if light and substrate are adequate, plants will grow.
Plant control should extend beyond eradicating undesirable species to en-
couraging desirable plants.
Sediment Buildup
Sand, silt, and organic matter from erosion, construction, shoreline collapse, urban
drainage, and other sources decrease lake volume and increase the shallow water
area. Not only can this interfere with recreational activities such as boating, but
shallow, nutrient-rich sediments encourage the growth of nuisance aquatic plants
and may contribute nutrients to the water column, thus stimulating algal blooms
as well. As internal productivity increases, organic matter accumulates and the
lake evolves toward an emergent wetland.
Good management of the watershed (see Chapter 6) will, of course, reduce
sediment entering a lake; but how do you deal with it once it's there?
Shallowness is the primary symptom to be considered here; you can address
this problem in several ways:
• Reserve part of the lake as a detention and settling area
(cleaning it out as needed to maintain its function) to protect the
remainder of the lake. Such basins will usually have to be quite large
to capture the finest and most pollutant-laden material. Smaller basins
to capture coarse sediments are more practical, but may not protect
the lake from sedimentation impacts. This is more a preventive than
restorative technique; and giving up a substantial portion of a lake is
usually unacceptable.
I lant control should
extend beyond
eradicating undesirable
species to encouraging
desirable plants.
285
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Managing Lakes and Reservoirs
Humic substances:
Derived from humus, the
organic portion of soil
resulting from decomposition
of plants and animals.
• Raise the water level: Outlet limitations usually make this very
difficult — and you certainly don't want to flood shoreline properties.
• Resuspend the sediment to move it downstream: This is not
environmentally sound and is illegal in most areas.
• Cause the sediment to decay or compact: Drawdown some-
times compacts sediments, but usually does not significantly change
water depth. Adding natural or engineered microbes, usually in con-
junction with aeration, is advertised as accelerating organic sediment
decay, but scientific evidence is lacking. Also, most organic mucks need a
great deal of oxygen; supplying enough oxygen for decomposition
almost guarantees resuspension of particles, increased turbidity, and
downstream transport. And some materials simply don't decay.
• Remove the sediment: Dredging is a major operation, but can
provide major restorative benefits if done properly.
Removing sediment is the only practical way to consistently increase water
depth, and dredging has become one of the most frequently prescribed tech-
niques. Key steps include:
• Perform a proper feasibility study of the lake and disposal sites.
Consider the potential negative impacts and how to avoid them;
otherwise, they can be severe. Carefully assess sediment attributes
(quality and quantity).
• Design the dredging project — this involves much engineering and is
best done by professionals.
• Be aware of all costs; dredging projects are expensive — but can
improve water depth over the long term.
• Secure permits, which are usually extensive.
Continual sediment loading will return the lake to its pre-dredged condition,
so you must control external loading — remember, watershed management is
essential — to protect your investment in dredging. See the algal and rooted
plant control sections of this chapter for more details on dredging.
Non-algal Color and Turbidity
Colored drinking water often indicates high concentrations of algae or humic sub-
stances. Algal control has been addressed previously in this chapter. Humic sub-
stances in drinking water are removed in a treatment facility, not in the reservoir
itself. It would be difficult and expensive to sustain this treatment for an entire lake.
Humic substances act as a natural dye, limiting the depth of rooted plant
growths, and reducing phosphorus availability to algae. Consider these natural
benefits before removing humic substances.
Color in drinking water drawn from a deep source (and sometimes the
metalimnion) is often caused by a high concentration of iron or manganese in the
raw water. These metals may also impart taste to the water. Aeration is generally
used to eliminate this buildup in a reservoir, although artificial circulation might
also be applicable. For more information, see the algal control section of this
chapter.
286
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Anoxia and Related Issues
Anoxia (the absence of oxygen) is a natural process common in U.S. lakes for a
number of reasons:
• Decaying organic matter and sediments need oxygen — people's
activities in the watershed can greatly accelerate the natural process
of sediment accumulation.
• Oxygen can't enter the hypolimnion of a stratified lake from the
atmosphere, so if there's not enough oxygen already in the
hypolimnion to handle the oxygen demand, it may become anoxic.
• Shallow lakes may also become anoxic, especially where the sediment
meets the water, if the sediment needs more oxygen than the
atmosphere is delivering.
So what happens in an anoxic hypolimnion?
• Iron, manganese, ammonia, and dissolved phosphorus often
accumulate to undesirable levels.
• Habitat for coldwater fish and daytime refuge for zooplankton are
minimized.
And the solution?
• Adding oxygen is a logical solution to anoxia; this may involve artificial
circulation (destratification) or hypolimnetic aeration.
• Removing oxygen-demanding sediments by dredging can also be
effective, but is a complicated and expensive process.
• Selective discharge may prevent anoxia if water can be discharged
faster than the rate of oxygen loss, but this is an uncommon situation.
• Anoxic impacts to water supplies can be minimized by elevating the
raw water intake from the hypolimnion to the epilimnion. This can
introduce taste and odor or other algal problems, but may be
preferable to using an anoxic supply.
Review the algal control section of this chapter for a more thorough discus-
sion of these techniques.
Acidification
Acidic waters can harm many aquatic organisms, principally by leaching sodium
chloride from the body fluids of fish and other organisms. Important sport fish
species may disappear at pH levels below 6.
Acidic lakes occur in two areas:
• Where the soils have little natural buffering (neutralizing) capacity; and
• Where acid rain and other human or natural processes cause
acidification of water bodies.
Poorly buffered lakes subject to considerable atmospheric deposition of acid
compounds have been the most widely publicized examples, but lakes subject to
copper sulfate and unbuffered aluminum sulfate applications can also acidify. Acidic
287
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Managing Lakes and Reservoirs
drainage from mines affects thousands of miles of streams and numerous lakes
throughout Appalachia and in other coal and metal mining areas.
Some waters are moderately acidic because they pass through naturally
acidic soils. A naturally acidic system can be severely disrupted by artificially rais-
ing the pH. Lakes dominated by these waters possess an adaptive ecology that
should not be confused with that of lakes impaired by cultural acidification.
Clearly, controlling atmospheric emissions is the best way to counteract acidi-
fication — attacking the problem at its source. But where damage from cultural
acidification must be mitigated on an in-lake basis, acidity is most often managed by
adding neutralizing materials. Olem (1990) describes methods of counteracting
acidification:
• Limestone, a natural mineral, is often the major component of
surface water buffering systems that neutralize acidity. Limestone
works on lakes just like common antacid tablets work on our
stomachs. Calcium carbonate is the active ingredient in both.
And, because it is used extensively for agricultural liming, limestone
is easily available at a low cost. It's usually applied by boat (helicopter
if the lake is not accessible by boat); a limestone-water slurry is
spread over the lake surface.
When added to surface water, limestone dissolves slowly, gradually
increasing the pH. It is often desirable to add enough limestone so that
some settles to the bottom of the lake. This "sediment" dose continues
to slowly dissolve over time.
Limed water bodies typically increase in pH to levels between pH
7 and 9. These pH levels are best for growth and reproduction of
many aquatic organisms, and reduce the concentration of toxic forms
of aluminum. The effects typically last about twice the lake detention
time.
• Injection of base materials into lake sediment is an
experimental procedure that has been applied to only a few lakes
(Lindmark, 1985; Willenbring et al. 1984) but shows promise for those
with short detention times. The technique injects neutralizing
materials such as limestone, hydrated lime, or sodium carbonate into
the sediments of acidic lakes, to gradually change lake pH and increase
acid neutralizing capacity in the water column during spring and fall
lake turnover. This treatment should last about five to seven times
longer than adding limestone to the lake surface.
• Base injection may release phosphorus from the sediments to the
water column, thus increasing productivity. In low fertility systems
commonly associated with low pH, this can benefit fish. But it can also
disrupt the benthic community and increase turbidity, and is expected
to cost more than liming lake water directly. This technique is
generally limited to small, shallow lakes with soft organic sediments;
they must be accessible by roads adequate for transporting materials
and application equipment.
• Pumping naturally alkaline ground water into a few lakes has
also been attempted.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Toxic Substances
Substances that cause negative reactions in exposed organisms are called "toxic".
An overused and frequently misused term in recent years, it is a generic label put
on a wide variety of natural and anthropogenic compounds.
Lakes often become sinks for toxic materials generated in the watershed —r
such as DDT and PCBs — but only a few toxic substances originate in the lake it-
self. These include ammonia, hydrogen sulfide, methyl mercury, and algal toxins.
Disinfection byproducts (DBFs) result from reaction of organic mole-
cules with disinfection chemicals (mainly chlorine) in water treatment to form
potentially toxic compounds. The organic molecules may come from the water-
shed, primarily as decaying plants, or from vascular plants and algae in the reser-
voir. The concentration of these organic molecules is expected to be higher in
more eutrophic water bodies. Consequently, watershed management and most
in-lake techniques for controlling algae and vascular aquatic plants can limit DBF
formation (Cooke and Carlson, 1989).
The initial source of mercury in many lakes is not known, but its widespread
distribution suggests airborne dispersion; waste incinerators and fossil fuels are of-
ten blamed. Once in the aquatic ecosystem, mercury can be transformed into a
highly toxic substance. While dilution, flushing, or dredging can improve the situa-
tion, methyl mercury contamination has no simple in-lake solution.
Artificial circulation or aeration can usually control ammonia and hydro-
gen sulfide. Most algal control techniques can minimize algal toxins, which are
most often produced by blue-greens but can come from other algae as well.
Natural uptake, adsorption, and settling usually remove or inactivate toxic
substances introduced to a lake. The sediments in urban and agricultural lakes of-
ten contain substantial quantities of a wide variety of potentially toxic com-
pounds, but these compounds usually interact very little with the overlying water
column. Removing the sediment can be desirable, but disposal of contaminated
dredged material can be complicated and very expensive.
Where a drinking water supply is involved, raw water is commonly treated
with coagulants, adsorption, settling, and/or filtration to minimize the amount of
potentially toxic substances in water sent on to consumers. In general, treated
water supplies are very safe for consumption.
Pathogens
Controlling the biological pathogens (viruses, bacteria, fungi, and protozoa) of
concern to humans is usually a matter for watershed management. Such patho-
gens come mainly from waste materials, especially animal wastes, so management
of wastewater treatment plants, on-site (septic) disposal systems, and concen-
trated animal feedlots is important. Stormwater runoff is often a source of patho-
gens as well, and requires attention in watershed management. Exceptions would
include direct inputs from humans, waterfowl, beavers, and other wildlife or live-
stock using the lake.
Pathogens of special concern in water supplies today include the protozoans
Giardia and Cryptosporidium. The former is associated with a variety of wildlife, but
most notably beaver, while the latter is linked to livestock, especially young cows.
Both produce debilitating symptoms in humans, and Cryptosporidium has been fa-
tal in some cases (Payer, 1997). Risk of infection in recreational lakes is very low;
current regulations concentrate on contamination of drinking water supplies.
Pathogen: A specific
causative agent of a disease.
289
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Managing Lakes and Reservoirs
Pathogens are not easy to measure for several reasons:
• Fecal coliforms, bacteria that inhabit the intestinal tract of
warmblooded animals, are often used to indicate pathogen presence,
but these bacteria are not usually pathogenic themselves.
• Other forms of bacteria can be assessed by culture techniques, but
this process is not rapid or completely reliable.
• Detection of Giardia and Cryptosporidium depends mainly on visual
examination of samples with a microscope, and is not extremely
reliable (LeChevallier et al. 1997).
Most pathogens live only briefly in well-oxygenated waters, although some
do form cysts that can become active pathogens after ingestion. Aeration and cir-
culation techniques, discussed previously in this chapter, sometimes remedy this
problem in the lake. Drinking water subject to possible pathogenic sources
should be treated by filtration and disinfection. Although risk cannot be elimi-
nated in water supplies, proper treatment (as stipulated under the Safe Drinking
Water Act) will minimize it.
Undesirable Fisheries
Fish production is directly related to lake or reservoir fertility. This relationship is
also the source of many fishery problems. While nutrient-rich waters may pro-
duce a larger fish population, they may also promote intense algal blooms, anoxia
in deeper waters, or serious fish imbalances (predators vs. prey, bottom vs. water
column feeders, or age and size classes).
At the other end of the spectrum, lake or reservoir fertility may be so low
that fish grow and reproduce poorly, and stocking efforts will usually fail if the
lake is not fertilized. Lake Mead, in Nevada and Arizona, is a case in point (Axler
etal. 1988).
Thus, both low and high fertility situations have become targets for manage-
ment where fishing is a high priority. Some may say it's unethical to drastically
change a natural system to meet fishery goals, but management may be the only
way to maintain the system where the aquatic habitat has been created by humans.
Fishery issues include:
• Small population size — not enough fish, usually as a result of lack
of fertility, but also from overfishing, disease, anoxia, or toxic
substances;
9 Undesirable size distribution — stunted fish populations, usually
as a result of low mortality rates and overcrowding, leading to
sub-lethal food shortages and slow growth;
• Predator-prey imbalances — not enough predators to keep the
prey species in check (leading to an undesirable size distribution) or
not enough prey to support the desired level of gamefish;
• Non-native or disruptive species — presence of enough of an
undesirable species to impact the desirable species (lamprey damage
to trout) or quality of the fishing experience (turbidity created by
carp); and
290
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• Poor fish condition — low weight to length ratios, tainted flesh
(taste), contaminated tissue, poor appearance (parasites).
Just as with lake restoration, the condition of the fish community must first
be diagnosed before beginning a fish management program. This usually involves
fish sampling to assess the condition of the present fish community. Before at-
tempting to diagnose a fishery condition, consult with state fisheries profession-
als. Fish management should also involve an understanding of the physical,
chemical, and biological features of the lake aside from fish; a diagnostic/feasibility
study is a useful tool in virtually every aspect of lake management.
Fishery management in lakes and reservoirs falls into three broad categories
(Baker et al. 1993):
• Habitat management — alteration of the physical and/or chemical
features of the lake to suit a fish species or group. Aeration to reduce
anoxia, liming to reduce acidity, dredging to expose gravel substrate,
placement of artificial reefs, and structuring the plant community by
removal or plantings are all examples.
• Fish manipulation — stocking or removing fish of selected species
or sizes to enhance the food base or remove competitive or
predatory limits on a species or group. Removal of planktivores
(sunfish) or rough fish (carp), stocking of top predators (pike or bass),
or addition of prey species (minnows, alewife, shad) come under this
heading.
• Managing fishing pressure — setting limits on the types, sizes, or
numbers of fish that can be removed to minimize human disruption of
the fish assemblage. Fishing regulations should not only enhance equity
of opportunity for anglers, but should act as a tool to maintain or
improve fishery characteristics over time.
All the habitat management techniques except artificial reefs have been dis-
cussed elsewhere in this chapter. Artificial reefs are somewhat controversial, in
that it is not clear they help fish production. Certain species will benefit, but the
concentration of those fish around reefs may favor anglers more (Bortone,
1998).
^ Fish manipulation typically revolves around stocking or removal.
Removal has been practiced on large and small scales by a variety of
methods (McComas, 1993). Piscicides, such as rotenone, were widely used
in the mid-1900s, but are less popular today as a consequence of
unintended side effects. Still, chemical control is generally more effective
than physical techniques such as netting or angling. Drawdown can elimi-
nate most species of fish, but complete drawdowns are uncommon and
also have serious side effects. Biological control, which generally involves
adding larger predator species, has become more popular over the last
quarter century. Fish stocking, while indiscriminate in decades past, is now
somewhat more tightly controlled and normally requires a permit from
the state fish agency.
In either case, the goal is to alter the ratio of predators to prey, or
large fish to small fish, or one species to another, so that one or more spe-
291
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Managing Lakes and Reservoirs
lanaging fishing
jjmeans managing
•people, which requires a
ifirm scientific basis and
!the ability to both
..... cjncl ............................................
^ enforce decisions.
P N egative aspects of
^regulations are mainly
Irelated to angler
[dissatisfaction with
IpeJng regulated, not
;with impacts on the
flake itself.
cific species will become more abundant. An exception would be put-
and-take stocking, in which catchable-sized fish are placed in a lake for im-
mediate angling enjoyment and may have little long-term impact on the
fish community.
Fish manipulation requires careful planning, along with followup moni-
toring and usually repeat manipulations on an annual to five-year basis. Its
primary negative impacts are:
• Loss of native species or genetic stocks: stocking of
hatchery-reared trout has become more controversial because of
its effect on native genetic diversity.
• The ever-present potential for biological interactions to affect the
lake with unexpected severity: for example, alewife or shad stocked
to provide food for gamefish can produce a trophy fishery, but can
also greatly reduce zooplankton and the average zooplankter body
length and algae grazing potential (Wagner and Carranza, 1986;
Brandt, 1998). Alewife and shad can discourage recruitment of
gamefish through food competition with juveniles and possibly
direct predation on eggs and fry. Adult gamefish growth has
therefore been enhanced at the expense of algal biomass control,
water clarity, and gamefish recruitment.
In artificial or intensely managed systems, however, fish manipulation
may be necessary to achieve fish production and fishing goals.
Managing fishing means managing people, which requires a firm scientific
basis and the ability to both communicate and enforce decisions. Controls
range from closed seasons to size or catch restrictions to encouragement for
keeping certain types or sizes of fish (Baker et al. 1993). Management options
include:
• When fish are more susceptible to fishing pressure at certain
times, they may need to be protected by a closed season.
• Where fishing pressure is intense, fish must be protected until
they reach a reproductive age if the population is to be naturally
sustained, and limits on fish size and catch per angler may be
necessary to ensure continued fishing.
• Where small and large fish need protection, a slot limit can be
instituted, allowing only an intermediate size class to be taken.
• If there are too many fish of a given species for the system to
support, thinning by angling is possible, although this has rarely
reduced the stock to the desired level by itself (McComas, 1993).
Fishing regulations tend to maintain, not change fisheries. Regulations
are generally intended to minimize undesirable shifts in population charac-
teristics. Negative aspects are mainly related to angler dissatisfaction with
being regulated, not with impacts on the lake itself.
Some fish management techniques are intended to enhance aquatic
conditions, not angler success:
• Removing bottom-feeding fish from shallow lakes is a prime
example (see algal control techniques). Fish are often removed to
increase zooplankton size and biomass, so they will graze on algae
and thus improve water clarity.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• Grass carp are stocked to reduce vascular plant growth, often to
the detriment of other fish species and with large increases in
algal biomass.
Animal Nuisances
Many animals annoy other lake users, but those that affect humans get the most
attention in management programs: various insects, waterfowl, aquatic inverte-
brates, and rodents. In some cases, management for human protection or comfort
is consistent with other lake goals and sound ecological principles, but in many
cases we are fighting nature to meet human goals.
^ Insects that carry diseases or are simply annoying (mosquitoes, midges,
blackflies, other biting insects) have little effect on water quality and may
actually fuel fish production, but are often targeted because of their nega-
tive interactions with humans.
• Chemical solutions: pesticide applications that may also affect
other non-target organisms.
• Physical solutions: drying up possible breeding areas (which
may or may not affect associated lakes), dredging to deepen the
habitat, and flushing to control nuisance populations.
• Biological solutions: funneling production of problem insects
into other biological components of the system, most often fish.
As with algal control, humans have technological superiority but an
evolutionary disadvantage; complete control of insect pests is rarely
achieved — lake users must accept some level of co-existence.
^ Waterfowl become nuisances when they become abundant enough to
add nutrients to the lake or interfere with recreation either directly or by
raising bacterial counts (and thus forcing beach closures). Canada geese
are the most cited offenders, but a variety of ducks and seagulls can also
cause problems. Control depends largely on the priority of lake uses.
• Waterfowl breeding and migration areas are best used to enjoy
the diversity of waterfowl they attract, so controls should be
aimed at helping the waterfowl: preventing diseases and managing
the population. Recreation is secondary in these areas, unless
hunting is a priority use.
• Where the lake is used primarily for recreation or water supply,
taking action against larger populations of waterfowl may be
justified.
Waterfowl control may involve scare tactics, including exploders,
shellcrackers, noisemakers, scarecrows, and balloons; or dogs, chemical re-
pellents, or habitat manipulation to keep them away from certain areas (U.S.
Dep. Agric. 1986; McComas, 1993). Most scare tactics will work for some
time, but waterfowl will eventually get used to them and become immune
to the technique. Dogs are an exception if they remain aggressive. Chemical
repellents are inconsistent, and must be reapplied frequently.
Habitat manipulation can succeed, and is ecologically consistent with
most other management goals, but takes time and often requires more ef-
.
A,
\s with algal control/ -
humans have
technological superiority,
but an evolutionary
disadvantage; complete
control of insect pests is
rarely achieved — lake
users must accept some
level of co-existence.
293
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Managing Lakes and Reservoirs
fort. In the case of geese, plant barriers between water and land will often
discourage geese from using an area. Dense stands of cattail, iris, or other
stiff plants can physically impede goose movement, and tall grasses limit
forage and visibility. Fencing at the edge of the water also inhibits use by
geese. Wires, fishing line, or other overhead physical barriers bar both
geese and seagulls from targeted areas.
Direct population control is also possible where laws permit, and
includes shooting, trapping with relocation, and shaking of eggs (addling).
Eliminating supplemental feedings is appropriate, and food poisoning has
been employed in extreme cases.
V Aquatic invertebrate nuisances include certain larval inverte-
brate stages that cause swimmer's itch, leeches, other invertebrates that
bite or infect humans, and non-native zebra mussels that drastically alter
the flow of energy in a lake. Although copper sulfate or other pesticides
kill them, these treatments may harm the aquatic environment. Methods
that use the ecology of the problem species against it are much preferred.
Several fairly simple techniques can help alleviate this problem:
• Swimming areas can be altered to favor humans and exclude
most nuisance invertebrate species by limiting plants and soft
substrates, placing barriers around the edge of the swimming
area, and changing water chemistry.
• A few salt blocks can increase the salt concentration to a level
leeches find objectionable.
• Limiting snails and waterfowl in swimming areas by physically
removing them or changing their habitat can minimize the
number of larval invertebrates responsible for swimmer's itch.
V Tfie zebra mussel problem deserves special mention as this non-
native species expands at tremendous rates in suitable waters, with signifi-
cant effects:
• Because they filter the water, zebra mussels greatly enhance
water clarity, reducing food resources for zooplankton and fish.
• More energy is funneled through benthic pathways, favoring
different species offish than usually found in the affected lakes.
• Intake or discharge pipelines can become clogged.
• Bottom coverage creates a hazard for swimmers and waders,
who can be cut on the sharp edges of an open shell.
• Growth on boats, mooring lines, and buoys creates hazards and
maintenance problems.
Zebra mussels may be controlled biologically through predation by
certain species, including the freshwater drum, but this has not been
widely successful. Several other approaches have been tried:
• Standard treatment chemicals such as copper or chlorine can be
effective, but in many cases the mussels can't be exposed to the
chemicals long enough to kill them.
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• Additives to paints, such as hot sauces, can minimize the
attractiveness of surfaces for colonization, but are not completely
effective for an extended period of time.
• Physical removal is possible but labor-intensive.
• Some treatment facility operators limit control efforts, preferring
co-existence strategies such as oversized pipes (Sarrouh, 1998).
v Beaver, muskrat, and nutria become nuisances through their
own efforts at manipulating their habitat. Burrows and dams create physi-
cal impediments to human use, and consumption of shoreline vegetation
promotes erosion. Other than direct trapping, control methods consist
largely of counteracting the tendency of these animals to adjust their en-
vironment (McComas, 1993):
• Remove dams — but you can also foil animals through tubes or
sluices designed to prevent intentional clogging.
• Discourage burrowing with flagstone, riprap, or wire mesh.
• Protect trees and shrubs with wire barriers.
• Use unpleasantly scented (usually non-toxic) chemical repellents.
User Conflicts
User conflicts result when one use of the lake negatively affects one or more
other uses. These may be between human uses such as water supply or recrea-
tion and non-human uses such as habitat for fish and wildlife. Or perhaps human
user groups have different priorities for lake use. Conflicts between non-human
user groups also exist, but tend to get minimal attention from lake managers.
The most controversial user conflicts in recent years relate to:
• Provision of water supply from reservoirs versus downstream flow for
habitat maintenance;
• Use of outflow for power generation versus desired water level for
other uses; and
• Motorized watercraft versus virtually all other lake uses.
Lake and reservoir management includes planning to meet the needs of water
users (Chapter 3), and conflicts must be anticipated and addressed. Politics and
economics will figure into conflict resolution as much as science, and the ability to
effectively deal with people is as important as expertise in any of these fields.
Resolving conflicts over flows and water levels tends to revolve around wa-
ter quantity allocations that bring about specific downstream flows or in-lake wa-
ter levels at specified times of the year (Blaha and LoVullo, 1997; Moyle et al.
1998). You must thoroughly understand the water budget of the lake or reser-
voir, its morphometry and storage capacity, and the operating limits of the con-
trol structures that hold or discharge water. You must also understand the
configuration and resource sensitivity of the downstream channel. You may then
be able to craft a management plan that satisfies all uses, or at least minimizes
conflicts. Sometimes, however, you will simply have to establish clear priorities for
lake use and manage accordingly.
tat
ike and reservoir
management includes
planning to meet the ;•
needs of water users, =
and conflicts must be
anticipated and
addressed. Politics and
economics will figure
into conflict resolution as
much as science, and the!
ability to effectively deal!
with people is as
important as expertise
in any of these fields.
295
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Managing Lakes and Reservoirs
nstead of going to the
extreme and banning a
use, look for the
-win; you may be
able to satisfy
everyone's "needs" if
you all understand the
nature of the conflict.
t should be possible to
esolve most recreational
pnflicts and achieve
talanced resource use if
|| parties are committed
o a fair allocation for
• I i nun i in i i i 11111 i
ach use.
^
•bill: i' Hi, ip'iip
should reflect all
, , ,
aspects of the project,
pi ...
from engineering and
^permitting through
factual dredging to
"shoreline and
1- i i i i i
^containment area
{restoration, and will be
highly lake-specific.
Most conflicts involving recreational lake use can be managed by allocating ei-
ther space or time (Jones, 1988; Wagner, 1990, 1994). Instead of going to the ex-
treme and banning a use, look for the win-win; you may be able to satisfy
everyone's needs if you all understand the nature of the conflict. Compromise by
restricting activities to certain spaces and/or times.
Motorized watercraft interfere with many other lake uses, mostly because
they're noisy and disturb bottom sediments in shallow areas. Personal watercraft
have received much attention for their noise impact. Try restricting the speed of
watercraft operating within some defined distance from shore and zoning certain
portions of the lake for non-motorized use. You might also restrict the hours of
engine operation or allow use of motors on only odd-numbered days or at cer-
tain times. Restricting engine size has been tried, but the connection between the
engine size and impacts is not so clear. Some approaches, such as limiting parking
space at the boat launch, combine space and time restrictions on boaters into
density regulation.
You must understand the motivation and use pattern of each user group if
you are to develop a mutually satisfying solution. It is also important to under-
stand the lake resource, as some features will predispose the lake to certain im-
pacts. Space zoning tends to work better on large lakes, while time zoning is
often necessary on small lakes. As with flow and water level conflicts, sometimes
decisions must be made on the basis of use priorities, but it should be possible to
resolve most recreational conflicts and achieve balanced resource use if all par-
ties are committed to a fair allocation for each use.
Cost of Lake Management
The cost of managing a lake or reservoir depends on several factors (Table 7-8),
and the process of estimating costs is highly lake-specific.
• The cost of chemicals depends on dose and volume to be treated,
each of which requires information about the system to be treated.
Costs are typically reported on a per acre basis, however, obscuring
some details.
* Harvesting costs depend on the machine to be used, the type and
density of the plants to be harvested, and the location of the
offloading point relative to the area targeted for harvesting.
Contractor estimates will incorporate costs for mobilization and
equipment maintenance that will not be obvious in an areal (per acre)
cost. Estimates derived by lake associations or towns that have
purchased a harvester should also include maintenance expenses, as
well as salaries and benefits for operators and insurance costs. Again, a
simple cost per unit of area harvested obscures the details and limits
the comparative value of the estimate.
• Estimating dredging cost is quite complicated, and involves substantial
knowledge of lake and sediment features, access and equipment
considerations, dewatering capability, containment area characteristics,
and ultimate disposal of dredged materials. The cost of each program
element is calculated and summed to derive the project cost, but for
comparison among dredging projects this value is often divided by the
quantity of sediment to be removed to yield a cost per unit volume
296
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
(typically per cubic yard). This cost value should reflect all aspects of
the project, from engineering and permitting through actual dredging
to shoreline and containment area restoration, and will be highly
lake-specific.
For any given lake and problem, comparison of costs for alternative manage-
ment methods should be based on a careful accounting of all expenses associated
with each method over the intended duration of benefits, recognizing how the
benefits vary for different techniques. Don't, for example, compare the cost of a
single herbicide treatment with a dredging project that should provide multiple
benefits for decades. Similarly, nutrient inactivation may control algae to the same
extent as aeration for less long-term cost, but will not increase hypolimnetic oxy-
gen levels as much. Comparison of contract harvesting versus purchase and local
operation of a harvester should be based on the cost over the expected lifetime
of the harvester (typically 10 to 15 years).
Separate costs into capital and operating expenses, as high capital methods
may require different approaches to funding and implementation, and may ulti-
mately affect the choice of technique. Estimators should also note any factors
that cause uncertainty of cost values, and express estimates as cost ranges for
each method of managing a given problem in a given lake. Cost ranges for alterna-
tive methods can then be compared directly and in light of other non-cost issues
that affect selection of management methods, such as variable benefits, permitting
requirements, and social acceptability.
While the lake-specific approach is recommended for serious comparisons
and detailed budgeting, it does require much information you may not have in
the early planning stages of lake or reservoir management. Thus, you may want
to make general cost comparisons among techniques or get an initial rough es-
timate for discussion purposes. Most lake-related texts cite specific cases and
associated costs, but extrapolating them to your case may be difficult. Where
appreciable cost data are available (e.g., dredging, nutrient inactivation, herbi-
cide treatment), the range is generally large as a consequence of lake- or
region-specific features.
Comparing Costs
With all of these caveats in mind, Table 7-8 compares costs (in 2001 U.S. dollars)
among selected techniques based on clearly outlined assumptions, a uniform unit
of application (per acre), a common target area (100 acres), and an extended peri-
od of benefit (20 years). The ranges in Table 7-8 are not all-inclusive, and some as-
sumptions may not hold true for even most possible cases. Cost estimates are
based on interviews with lake management practitioners across the country, but
are adjusted to reflect the added costs of design, permitting, and monitoring for
each technique.
Consider, for example, the costs Table 7-8 gives for addressing two primary
problems: excessive algal growths and aquatic macrophyte infestation. It is obvi-
ous that addressing these problems on an in-lake basis is expensive when consid-
ered over an extended period of time, no matter which technique is employed.
Preventing lake and reservoir problems would seem preferable to in-lake man-
agement wherever possible.
Very few techniques provide lasting relief at a consistently low cost. If algae
can be controlled with selective withdrawal through an existing structure (either
R_., . _ ...
eventing lake and
reservoir problems
would seem preferable
to in-lake management
wherever possible. .. .
Very few techniques
provide lasting relief at
a consistently low cost.
297
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Managing Lakes and Reservoirs
Table 7-8.— Cost of selected management options within lakes and reservoirs.
TECHNIQUE
ASSUMPTIONS
COST RANGE ($)
PER ACRE TREATED,
WITHOUT CONSIDERATION OF
LONGEVITY
OF EFFECTS
COST RANGE ($) FOR A
HYPOTHETICAL 100-ACRE
TARGET AREA OVER
A HYPOTHETICAL
20-YEAR PERIOD
ALGAL CONTROL
Herbicide Treatment
wilh Copper
Artificial Circulation
Aeration
Selective Withdrawal
Bottom Sealing
Sediment Treatment
with Riplox
Dredging
Nutrient Inactivation
Dilution
Flushing
Dye Addition
Partitioning for
Pollutant Capture
Biomanipulation of
Fish/Zooplankton
Copper sulfate powder/crystal
Chelated formulations
Shallow water circulation
Destratifying diffusion
Full or partial lift, prevention of
anoxia
Full or partial lift, DO>5 mg/L
Layer aeration, prevention of
anoxia within layer
Layer aeration, DO>5 mg/L
within layer
Necessary structures in place
Structural alteration and/or
treatment of discharge required
Artificial covers
Reverse layering
No major obstructions to bottom
treatment
Average sediment depth - 2 ft
Average sediment depth = 5 ft
Alum with no buffering, external
load controlled
Buffered alum treatment, external
load controlled
Water readily available
Piping, pumping, or structural
alteration necessary, and/or
water treatment necessary
Water readily available
Piping, pumping, or structural
alteration necessary
Detention time >1 month
5-acre detention pool
5-acre constructed wetland
Predator stocking
Planktivore removal
50-150
150-300
300-5000
500-7000
800-2000
1000-3000
500-1000
700-1200
<100
' 1000-3000
5,000-60,000
20,000-40,000
8,000-12,000
15,000-50,000
25,000-80,000
500-700
600-1000
500-2500
5000-25,000
500-2500
5000-10,000
100-500
10,000-40,000
15,000-75,000
500-1500
1 000-5000
100,000-1,200,000
300,000-2,400,000
70,000-350,000
90,000-400,000
1 80,000-300,000
280,000-400,000
120,000-180,000
1 80,000-240,000
50,000-100,000
200,000-1,000,000
1,000,000-6,000,000
2,000,000-4,000,000
1,600,000-2,400,000
1 ,500,000-5,000,000
2,500,000-8,000,000
50,000-140,000
60,000-200,000
1,000,000-5,000,000
5,000,000-25,000,000
1 ,000,000-5,000,000
5,000,000-10,000,000
200,000-1,000,000
75,000-200,000
75,000-275,000
200,000-600,000
400,000-2,000,000
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
Table 7-8.— Cost of selected management options within lakes and reservoirs (continued).
TECHNIQUE
ASSUMPTIONS
COST RANGE ($)
PER ACRE TREATED,
WITHOUT CONSIDERATION OF
LONGEVITY
OF EFFECTS
COST RANGE ($) FOR A
HYPOTHETICAL 100-ACRE
TARGET AREA OVER
A HYPOTHETICAL
20-YEAR PERIOD
MACROPHYTE CONTROL .^;. _ ' . '.. ^ ; ;. '_ ^;f^ [,L,^: '^ ^ f^- ' /, . ':. ., . ", • , '.'.' : . '.. :. . - :.-. ,
Cutting
Hand Pulling
Harvesting
Hydroraking or
Rotovation
Suction Dredging/
Harvesting
Benthic Barriers
Water Level Control
Dredging
Dye Addition
Herbicide Treatment
with Diquat
Herbicide Treatment
with Endothall
Herbicide Treatment
with Glyphosate
Herbicide Treatment
with 2,4-D
Herbicide Treatment
with Fluridone
Herbivorous Fish
Herbivorous Insects
No collection of vegetation
With removal
Moderately dense, submersed
vegetation
Very dense or difficult to
cut/handle
Softer submersed vegetation
Emergents and root masses
Primarily plants removed
Includes installation and
removal/annual maintenance
Necessary structures in place
Structural alteration required
Average sediment depth = 2 ft
Average sediment depth = 5 ft
Detention time >1 month
Liquid application
Liquid application
Surface spray application
Granular formulation, 1 00
Ibs/acre
Liquid formulation, single
treatment
Liquid formulation, 3 sequential
treatments
Pellet formulation
Grass carp stocked
Selected insects stocked
200-400
100-500
200-600
1 000- 1 500
2000-4000
6000-10,000
5000-10,000
20,000-50,000
<100
1000-2000
20,000-50,000
40,000-80,000
100-500
200-500
400-700
500-1000
300-800
500-1000
1000-2000
800-1200
50-300
300-3000
400,000-800,000
200,000-1,000,000
400,000-2,400,000
2,000,000-4,000,000
2,000,000-4,000,000
3,000,000-6,000,000
2,500,000-6,000,000
4,000,000-7,000,000
50,000-100,000
200,000-600,000
1,500,000-5,000,000
2,500,000-8,000,000
200,000-1,000,000
400,000-2,000,000
800,000-2,800,000
1 ,000,000-2,000,000
300,000-1,600,000
200,000-1,000,000
500,000-1,000,000
400,000-1,200,000
25,000-150,000
150,000-1,500,000
Cost estimates are based on prices obtained from cooperating lake management practitioners across the USA, adjusted to the
units of measurement for this table. While cost ranges do not include all possible situations, costs associated with each technique
are intended to reflect all directly associated expenses, including design, permitting, capital cost, operating cost, and monitoring.
Assumptions made to construct this direct comparison table may not hold true in all possible cases. Costs are given in 2001
U.S. dollars.
299
-------
Managing Lakes and Reservoirs
-In most cases, it makes
[more sense to narrow
the range of techniques
ffcased on non-cost '
Praetors, then develop a
Hake-specific cost
comparison of the most
I * ' , "kir
'appropriate methods.
NEPA: The National
Environmental Policy Act of
1969 that established a
national policy for the
environment, created the
Council on Environmental
Quality, and directed that
every recommendation or
report on proposals for
legislation and other major
federal actions significantly
affecting the quality of the
human environment include a
detailed statement on the
environmental impact of the
proposed action. For the
complete act, see Council on
Environmental Quality, 1991.
for water supply intake or by discharge of poor quality water), costs are mini-
mized. Likewise, if external loading has been reduced to an acceptable level, inac-
tivation of phosphorus with aluminum can provide long-term control at a cost
lower than for most competing techniques. However, both of these situations
could be considered "special cases" that do not include commonly encountered
costs for structural alterations and watershed management.
Certain types of rooted aquatic plants can be controlled by drawdown using
an existing outlet structure at a low long-term cost, but not all macrophytes will
be controlled and not all lakes have outlet structures that facilitate such draw-
downs. Herbivorous fish also offer a potentially low cost, long-term control op-
tion, but they don't consume all plant species with equal preference, control over
the fish is limited once stocked, and use of non-native species is illegal in some
states. Both drawdown and herbivorous fish can produce undesirable effects on a
lakewide scale, and counteracting these effects can raise costs considerably.
With few exceptions, the cost of addressing excessive algal and macrophyte
growths is as variable within techniques as among techniques. Again, the difficulty
of making generalized cost comparisons among techniques is underscored. In
most cases, it makes more sense to narrow the range of techniques based on
non-cost factors, then develop a lake-specific cost comparison of the most ap-
propriate methods.
Long-term cost might best be minimized by first using one or more applica-
ble and cost-effective lakewide techniques to control a major problem, then using
different techniques on a more local or infrequent basis to prevent its recur-
rence.
Permitting Lake Management
Nearly all in-lake management techniques require some form of permitting or
agency approval (see Chapter 8). Such processes add time and cost to the project,
but they underscore the importance of considering all possible impacts and mini-
mizing undesirable effects. Regulatory processes may include:
• General federal or state environmental review (NEPA or state
equivalent)
• Environmental impact reporting (if required as a result of NEPA)
• Clean Water Act Section 401 (water quality certification)
• Clean Water Act Section 404 (wetlands permit)
• State and local wetlands protection statutes
• Federal Endangered Species Act consultation
• State protected species statutes
• Fish and wildlife permit/notification
• Discharge permits (NPDES [see Chapter 6] and/or state equivalent)
• Aquatic structures permit
• Chemical application permit
• Dam safety/alteration permit
• Drawdown permit
300
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CHAPTER 7: Management Techniques Within the Lake or Reservoir
• Dredging permit
• Waste disposal permits
• Water diversion/use permit
Always consult local and state regulatory authorities before implementing a
lake or reservoir management plan, and build an appropriate lead time into your
program to acquire permits. Small projects or those involving limited impacts in
minimally sensitive systems may require only a month or two to gain approval,
while large-scale restoration and management efforts may require more than a
year to get permitted.
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306
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Chapter 8
Developing and
Implementing a
Management Plan
Planning is an essential aspect of managing your lake or reservoir — indeed,
planning and management cannot be separated. The investments you make
in developing and implementing your management plan will pay off in terms
of reaching your goals.
Why Plan?
If you follow a plan, you will reach your goals.
It can't be stated more simply than that. People concerned about lakes often say
they can't afford to plan. "We are only volunteers" or "We have just so much
money, so we want to spend it doing something, not planning." But many lake as-
sociations waste money on their lake because they did not have a plan.
People who don't prepare financial plans say, "I can't afford to do that right
now." Yet, people who prepare and follow financial plans are better off.
Businesses that prepare and follow business plans are more likely to succeed.
Indeed, most banks won't loan money to businesses without business plans.
Without a plan, you will not reach your goals.
Planning is doing. Planning goes hand in hand with management; it provides
the framework for what you do. With planning, management is more focused,
meaningful, and effective.
Crises often spark management actions that mistakenly substitute for plan-
ning. The discovery of a new exotic species or a proposed development on the
lakeshore often incites quick organization and action — but almost always out-
side of a meaningful planning context. After the urgency disappears, the organiza-
tion and the effort dissolve.
These situations argue for advanced planning — often the crisis could have
been avoided and effectively managed in the context of a plan.
1
hen good things
happen to us it is often
the result of planning.
The better the planning,
the better the result"
From/'Planning Ahead ....
Strategically." Olsen Thielen
Advisor, 1998.
307
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Managing Lakes and Reservoirs
imagine a complicated computer factory with white-coated technicians
emerging from rooms sealed with positive air hatches as they move products along an
ultra-sophisticated production line. This is the end result of many decades of research
gnd development and millions of dollars of capital expenditures.
Now imagine your favorite lake during a summer's sunrise, the
'technicians' are the many plants and animals of an ultra-sophisticated biological
production line: the end result of millions of years or evolutionary 'research.'
| Just as the factory, the lake did not just appear and it needs even more
|_ research and gtteniion_thgji^thj_computer factory, believe it or not. Otherwise, how will
y• we be able to maintain its engines of life? There are now too many contaminants and
£ unidentified influences from all of the people technicians in this factory — which might
f be fatal in the computer analogy.
I " " ;:"":::; :*; :::T.-r.;-.-:~':,r::
I What to do? We need to institute careful planning and attention to detail for our lakes
| to maintain their engines of life that we have come to appreciate, this will take
j^espyrces^ people, ingenuity, money, and commitment — to accomplish. -Bruce
| Wilson, Minnesota Pollution Control Agency. An analogy illustrating the importance of
I planning for lakes. December 1998.4>
What is a Management Plan?
Your management plan should answer the question:
v Who will do what by wfien anof with wfiaf
expected result? We can take this question apart to
form the elements of the plan.
• The who refers to the members of the lake community who are
willing to invest in the management of their lake. Including those
people who are unwilling or who are coerced into action will work
against sustaining a meaningful management program.
• The what refers to management actions directed toward a meaningful
and measurable objective. Here we must exercise care regarding the
source of funding. Outside monies — those coming from outside the
lake community — may tend to direct management actions to goals
not embraced by the community; or, these monies may make your
community complacent by delaying their investment in the lake.
• The when is important because without a deadline, there is no
commitment.
• Specifying an expected result forces an ongoing and critical
evaluation, which is essential to a long-term effort. The evaluation
must be objective and measurable, and it requires flexibility in the
management program.
Because lake and reservoir management is not an exact science, ongoing
evaluation is essential, and should, as a rule-of-thumb, be up to 20 percent of the
management effort. Lake McCarrons, Minn., went for 10 years without any critical
308
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CHAPTER 8: Developing and Implementing a Management Plan
evaluation; then, the community learned that the restoration program had not
improved the lake in any way (Metropolitan Council, 1997). Not attaining the ex-
pected result does not represent a failure of the management program, but
rather an opportunity to adjust and improve.
v 'Plan' is a verb, not a noun. Okay, it's really both, but the point is
the outcome of planning is not just a report, it must include action — and
that presents unique challenges. Unlike personal financial plans, which in-
volve one person or a couple, lake management plans must satisfy multiple,
often conflicting objectives. This means that preparing a lake management
plan requires a greater investment of time and resources. And stakeholder
participation and conflict management will be an important aspect of devel-
oping and implementing the plan.
The Planning Cycle
Planning for lake and reservoir management is a thoughtful, intentional, and sys-
tematic process that results in action. Investment in and attention to the details of
preparing and implementing a management plan will result in attaining your man-
agement goals. Planning and management go hand-in-hand in an ongoing cycle.
The two main ingredients in an effective management plan are discipline
and clear vision. Discipline keeps you faithful to and focused on the planning
process. Clear vision helps you develop reasonable goals and objectives.
When Do You Start Planning?
Now, any time, always. Planning is an integral part of management and begins and
continues with management as long as anyone cares about the lake or reservoir.
The basic steps:
• Step I. Get started, make a
commitment.
• Step 2. Analyze the situation, take
stock.
• Step 3. Set directions — vision, goals,
and objectives.
• Step 4. Evaluate alternative strategies
and actions.
• Step 5. Take action, implement.
• Step 6. Monitor and evaluate progress.
• Step 7. Repeat steps 2 — 6.
Steps I through 4 comprise the plan devel-
opment phase, and steps 5 through 7, the plan
implementation phase (Kehler et al. [no date]).
Although variations of this planning model exist
(see Chapters 3 and 6), the most important con-
sideration is to adhere to the basic elements (Fig.
8-1).
I allures don't plan to
fail; they fail to plan/
"Be like a postage
stamp; stick to it until
you get there."
"A dream is just a
dream. A goal is a
dream with a plan and
a deadline."
Harvey Mackay's
Column-ending 'morals';
United Features Syndicate
PLAN
IMPLEMENTATION
7. Do it
Again
PLAN
DEVELOPMENT
6. Monitor
Progress
5. Take
Action
2. Analyze the
1 • Get Situation
Started
t
\
3. Set
Directions
4. Evaluate
! Alternatives
Figure 8-1.—The planning cycle.
309
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Managing Lakes and Reservoirs
Steps I — 6 will normally take from 6 months to a year to complete, require
the involvement of dozens of people, and may include a professional planner or
facilitator.
The amount of time required to complete the planning cycle depends on the
complexity of your lake. A small pond in a condominium development requires
much less formal preparation than a more significant resource like Lake Tahoe.
Then, to be meaningful and lasting, some formal management entity must be em-
powered to oversee the ongoing management of the lake or reservoir. That or-
ganization should repeat the planning cycle every three to five years as a routine
part of its ongoing management.
Step I: Get Started
Getting started may be the most difficult step. Most people are not inclined to
plan. That's why people often do not prepare financial plans, save for their chil-
dren's college, write wills, or prepare for retirement.
Lake management planning involves many people — sometimes hundreds —
with potentially conflicting interests. Getting started requires a high level of or-
ganization, which is especially difficult since many participants are volunteers.
So, the hurdle of 'getting started' is
real. At a minimum, you will need
enough money, technical support, and
organizational effort to carry the initial
planning cycle. You may need help from
outside sources, but long-term manage-
ment will ultimately rely upon local re-
sources.
Start-up resources are akin to the
booster rocket that is required to break
the earth's orbit (Fig. 8-2): it must be
large enough to get the capsule into or-
bit, but once in orbit, the booster is no
longer needed. The capsule (manage-
ment planning) can then sustain its orbit
under gravity (local resources).
Figure 8-2.—Depicts the trajectory lacking
the energy to attain orbit, and therefore,
falls short.
Step 2: Analyze the Situation
Before a group can agree on how to manage the lake, they must find consensus
on where to start. A situation analysis —a snapshot of the physical, social, eco-
nomic, and political environment surrounding the lake or reservoir — prompts
this discussion and sets the initial direction for developing the management plan.
The situation analysis will include:
• A community survey to evaluate perceptions — and a "wish list"
— of lake conditions, changes in lake conditions, uses and values of the
lake, conflicts regarding the use of the lake and lakeshore, and
concerns about ongoing management of the lake. See Chapter 3 for
survey methods.
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CHAPTER 8: Developing and Implementing a Management Plan
• A physical inventory to summarize the chemical condition of the
lake, trophic state, fish and aquatic plant communities, shoreline plant
and animal communities, lake level fluctuations, pollution sources,
watershed delineation, estimates of pollution sources and amounts,
and land use. A physical inventory is not a detailed diagnostic or
engineering study.
• An assessment of the human environment that includes a list of
management and regulatory authorities, population projections,
planning and zoning matters, business and commercial interests,
management and control activities, and lake uses.
• A stab at a collective vision for the lake. The person preparing the
situation analysis normally gets a good sense of the community's
collective desires. It is useful to prompt the group with an independent
view of their situation. This will be the point of departure between the
matter-of-fact situation analysis and the remainder of the planning
process.
When you've completed it, summarize the situation analysis in a brief, non-
technical report that sets the initial directions for developing the management
plan.
Step 3: Set Directions
According to Top 10 Watershed Lessons Learned (U.S. EPA, 1997), the best plans
have "... clear visions, goals, and action items." Getting from a broad vision to dis-
crete, meaningful, doable actions requires a good deal of time and energy from
the group developing the management plan.
The management plan of the Blue Water Commission, the committee that
developed the plan to protect Lakes Nokomis and Hiawatha in Minneapolis, Minn.
(Osgood, 1998), contained numerous goals, objectives, and actions that were or-
ganized in a readable and logical format. The following example shows how the vi-
sion translated into goals, objectives, and actions (one each shown) for Lake
Nokomis:
• Vision: Lakes Nokomis and Hiawatha are the focal points for our
community and should be a showcase for Minneapolis. The lakes are
valuable natural assets that must be protected and improved for the benefit
of our neighborhoods and the city as a whole.
• Goal #1 (of 19): Eliminate nuisance algae blooms.
• Objective (one of several objectives to address this goal): Prevent 294
pounds of phosphorus per year from entering Lake Nokomis.
• Action I c: The Minnehaha Creek Watershed District will build three wet
detention ponds (specific designs and locations provided in the plan).
Visions — general
statements of where the lake
community wants to go and
what it will accomplish over
a given time span (usually 5
to 10+ years). Visions should
be comprehensive enough to
capture the thrust of the
planning process.
Goals — more specific than
visions, break into logical
pieces what is needed to
obtain vision, refer to
components of overall effort,
sometimes quantifiable.
Objectives — steps to
achieve the goals, describe
types of management or
activities and are quantifi-
able where possible.
Action Items — explain
who is going to do what,
where, and when; they
generally articulate how to
implement the objectives and
should be quantified if
possible; benchmarks of
existing conditions and/or
indicators should be
developed for action items.
— from Top 10 Watershed
Lessons Learned, U.S. EPA,
1997
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Managing Lakes and Reservoirs
Step 4: Evaluate Alternative Strategies
and Actions
The temptation at this point is often to go right to a solution without carefully
evaluating all options within the framework established in the first three steps.
Don't just pick a solution that looks good at first. Be thorough, prudent, and
systematic. The final management plan will probably contain actions that, in total,
will address several problem areas. The initial evaluation needs to recognize how
these actions might fit together to complement rather than conflict with the
plan's objectives.
Step 5: Take Action
Now the community is ready to begin the implementation phase of lake manage-
ment — at some point, someone has to take the prescribed actions. The manage-
ment plan per se will not take action, it will spell out who will do what by when and
with what expected result; this is the point where planning stops and implementa-
tion begins. Recall that both are critical and ongoing aspects of the planning cycle
(Fig. 8-1).
Much attention and energy needs to be invested in 'smell checking' possible
actions. It is easy to make recommendations that contain the word should, but
these are meaningless without an agreement as to whether the action will occur.
Consider a recommendation that reads:
The Pretty Lake Watershed District should
implement a phosphorus fertilizer ban.
This recommendation is basically one party directing another party to take a
specific action. What if the second party — in this case, the Pretty Lake Water-
shed District — does not agree with the action? Will they do it? Probably not.
So, rather than assuming someone else (here, the Watershed District) will
take action, that "someone else" should be included in the planning process. That
way, they will cease to be "someone else" but become part of the entire effort to
manage the lake wisely. Then, when everyone has agreed to the recommendation,
the plan will read:
The Pretty Lake Watershed District will (or has
agreed to) implement a phosphorus fertilizer ban.
Will, not should. All parties have reached agreement and now we know the
action will occur.
Step 6: Monitor and Evaluate Progress
Like children in school, a lake project must be monitored and evaluated. Although
you expect certain outcomes, environmental management is not a precise sci-
ence. You can expect a financial investment of $ 100 at 5 percent interest to re-
turn $105 in a year, but lake science is much less exact, and therefore much less
certain. The environmental situation is also constantly changing. So, monitoring
312
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CHAPTER 8: Developing and Implementing a Management Plan
Case Study: Lake McCarrons
Lake McCarrons is an urban lake in Roseville, Minnesota. A restoration project was
implemented in 1985 to reduce algae blooms in the lake.
__ In 1996, 10 years after the project began, lake residents complained of persis-
tent algae blooms and obnoxious aquatic plants. A situation analysis revealed that:
1. Lake phosphorus concentrations had not declined. Likewise, algae levels and
water clarify had not improved. Thus, the project had not met the goal of low-
, .ering phosphorus arid reducing algae blooms; :
"_<: 2. While the lake had been continually monitored^ progress had not been evalu-
, , ated. - ; ": -•-:-- ':,::••"'-••' -:•>'-... ,;:: ••:-'.. ' •'• . .i .v
3...Nuisance aquatic plants were still a problem.
This illustrates the importance of two critical steps, in the planning process. First,
the community was not involved in setting the initial directions for the plan (Step 3). If
they had been, the plan would have recognizedjrfieir concern \Vith nuisance aquatic
.plants. Second, after a decade of monitoring, it was clear the lake's condition had not
^improved, but since no critical evaluation was built into the planning process, the plan
has never been modified to better address its goals (Step 6). —Osgood (1996a) and
' 'Aetropolitan Council ('1997J".l •"'..'"' ''''"•'• '""" •^""^''""''''f «?"»»^:-. •' •. •• ;- . ••.
and evaluating progress help you track what's really going on so you can make
adjustments in the management program.
Finally, over a longer time, the perceptions and expectations of those who
use and value the lake may also change. At some point, normally after five to 10
years, it is time to begin another planning cycle. With sound monitoring and
evaluation in hand, the subsequent planning cycles should be more focused than
the initial effort.
Monitoring and evaluation are designed to assure performance of the man-
agement program, to determine whether it's meeting your stated goals and objec-
tives. Mid-term failure to meet your objectives does not imply a failure of the
management program, but instead offers an opportunity to better understand,
then make adjustments.
Given the inherent uncertainty in environmental management and the ongo-
ing need for up-to-date information, monitoring and evaluation are essential in
managing lakes and reservoirs. They should comprise about 20 percent of the
management effort.
Step 7: Do it Again
Planning should never stop. After the initial effort, the emphasis on planning will
fade; but it should never die. After awhile the basis for your plan will change as the
environment changes, technologies change, human needs and expectations
change, the economy changes, even your lake changes. Just as we periodically re-
view our business or retirement plans to keep them up to date, so must we re-
view our lake management plan.
i fanning should
never stop.
313
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Managing Lakes and Reservoirs
/"Always remember,
while take ecosystems
can function very nicely
Without people/ it is
precisely the human
integration that prompts
the need for
management.
Sustaining the Management Effort
To be effective and sustainable, a lake planning and management program must be
organized and focused. It takes work to keep organizations focused and it takes
energy to sustain a desired condition in a lake or reservoir.
To realize your lake management goals, you must sustain your management
efforts by:
• Building a dynamic, locally-based management organization that
focuses only on managing the lake or reservoir.
Without formal organization, a management effort may be unfocused, inef-
fective, and short-lived. Organizations built around crisis issues or loosely put to-
gether tend not to last. On the other hand, organizations that are formally
organized and focused will:
• Focus on comprehensive concerns instead of single issues
• Be anticipatory instead of reactive
• Be well connected with their community
« Have dynamic leadership instead of burning out their leaders
« Focus on programs instead of projects
• Tend to have volunteer workers instead of volunteer leaders
• Seek solutions instead of blame
• Be oriented toward problem-solving instead of problem-finding
To sustain a credible and long-term management effort, the organization
must:
• Be directed by leaders with a close connection to the lake community
• Have a clear vision
• Have a sound development strategy
Build a Local Management Organization
The community — those groups, organizations, users, and individuals closest to
the resource — is in the best position to manage the lake for the long run. There-
fore, you must either identify or create a local organization to assume responsibil-
ity for the management plan.
This local lake management organization must engage the lake community in
meaningful management actions for the long run. But maintaining the organization
requires work: time, resources, and money.
Work that must be done by people — the members of the organization. Al-
ways remember, while lake ecosystems can function very nicely without people, it
is precisely the human integration that prompts the need for management. Build
your organization on the solid base of those who use and value your lake: year
'round and seasonal residents, local businesses, people who treasure it for a vari-
ety of reasons.
You can't expect everyone in your watershed to be interested in your lake,
however: the geography of the lake community may not coincide with the water-
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CHAPTER 8: Developing and Implementing a Management Plan
shed boundary. Thus, the watershed approach to lake management, while an im-
portant element of the physical system, may be less significant in the social
context (see also Osgood, I999b). Keep this in mind as you develop your lake
management plan.
The point is that no 'one-size-fits-all' organization suits all lakes and reser-
voirs; the organization must be tailored to the unique circumstances of the re-
source.
Key Characteristics of a
Successful Watershed Organization
• Full-time employees •-,' •:. .
• Established office space and equipment ••";•
• Access to water qualify information
• High-level concern for water quality ;
• Water quality monitoring program in place
• Interest in (and encouragement of) citizen participation
:_ • Presence of a public outreach program • . '.
Source: from Environmental Ground, no date
Involve the Whole Lake Community
The lake community is the people, groups, and organizations that use and value
the lake. Sometimes called stakeholders, these people should be called upon to
develop and implement the management plan. They are, after all, the community
for whom the lake is being managed and to whom you will turn to sustain the
management effort.
Identifying the lake community is critical. Select people with a stake in the re-
source. Take care not to leave key players out of the planning process, but avoid
too large a number — many interests will have no stake in the resource and can
dilute the planning effort. In both cases, the planning suffers.
The following categories of people, groups, and organizations may be in-
volved:
• People. Lakeshore owners, neighbors, residents, and others, including
members of related lake associations.
• Groups. Lake-related businesses, chambers of commerce, and lake
user groups (for example, anglers, water skiers, swimmers, divers,
wildlife observers).
• Organizations. Governmental agencies, water utilities, tribal
governments, municipalities, special units of government, religious
organizations, and environmental and conservation organizations.
L
he watershed •;
approach to lake -j
management, while an
important element of the,
physical system, may be:
less significant in the
social context (see also
Osgood, 1999b). Keep
this in mind as you
develop your lake
management plan.
I he lake community is
the people, groups, and
organizations that use
and value the lake.
315
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Managing Lakes and Reservoirs
ere 'ecosystem' is
'{considered in the
<»
: broadest sense:
^comprised of the lake or
• • *.*
f reservoir, the people/
Jand the watershed —
•plus all their physical,
.social, and political
ffci "! I !' ' IlinnSi « S „_ , :.^,.
interactions.
Not all of these people and organizations need to be involved. Remember to
include all with a stake in the resource, but no more. When assembled, the stake-
holders should be engaged to act in their mutual interests. Their management ac-
tions will result from a desire to act, rather than from an outside directive; and
their motivation will come from their 'ownership' or value of the resource.
Consider Hiring a Professional Planner
or Facilitator
The role of the planner is not so much to write the plan, as to direct its develop-
ment and facilitate agreements required to implement it. The planner should be
familiar with lake management, versed in planning, and skilled in conflict resolu-
tion. It is important that the planner not be associated with or attached to any of
the interests of the stakeholders — the planner must be neutral. This frees the
planner to facilitate all discussions and negotiations even-handedly and fairly,
thereby assuring that the plan works for the community.
Tips for selecting and hiring a planner/facilitator:
• Know what qualifications you need, and
• Check references.
Focus on the Whole Ecosystem
Here 'ecosystem' is considered in the broadest sense: comprised of the lake or
reservoir, the people, and the watershed — plus all their physical, social, and po-
litical interactions. These elements are the heart, soul, and backbone of a mean-
ingful management program.
• The lake (heart) is the primary management focus.
• The people (soul) are the lake community. They provide the vision and
goals. After all, the people are the ones who care most about the lake
and for whom the lake is being managed.
• The watershed (backbone) is the basic management unit.
The lake or reservoir, of course, is the main focus of the management plan.
The lake ecosystem is much more complicated than the unpleasant consequences
of too much phosphorus, the classic management focus. Fish and aquatic plant
communities are key elements of the lake ecosystem that require equal attention
for sound and sustainable ecosystem management. The interactions of these eco-
system elements are complex, but critical to sound management (Jeppesen et al.
1997; Moss et al. 1996; Osgood, 1996b; and other chapters in this manual).
First, identify the needs and interests of the lake community. Hu-
man needs and interests can be translated into environmental attributes and then
into lake-specific objectives (see Chapter 3). Be careful when using lake standards
or criteria as a guide for management objectives. Because many in the lake commu-
nity may not understand how they were developed or applied, using standards or
criteria may be a distraction. Better to first tie a management need to a human
need (Walesh, 1999).
Those needs can differ drastically, as illustrated by two lake associations in
the Twin Cities (Minnesota) metro area. The Mooney Lake Association's main
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CHAPTER 8: Developing and Implementing a Management Plan
management objective is to keep the Secchi disk transparency greater than 3 feet.
When the lake clarity falls below this, they apply copper sulfate and the clarity in-
creases to about 4 feet. This level of clarity is in the lowest 10 percentile for all
lakes in the metro region (Osgood, 1988), and well below the region's water
quality standard, but it exceeds the needs of the Mooney Lake Association
(Osgood, 2000b). Indeed, when the Secchi disk reaches 4 feet, the president of
the Mooney Lake Association says the lake 'sparkles.'
In contrast, the Christmas Lake Association aims to keep its lake's clarity
above 17 to 20 feet (Osgood, 1995). Christmas Lake is among the clearest lakes in
the region — well above the top 10 percentile. The 'normal' clarity for lakes in
this region is 7 to 10 feet, but that has no relevance for either association. Achiev-
ing a 'normal' lake clarity would be unthinkable for the Mooney Lake Association
and a disaster for the Christmas Lake Association. Here, each organization man-
ages its lake to meet its unique needs and interests.
Learn from this example that societal or regulatory 'standards' or 'norms'
may not jibe with the needs and interests of the lake community. You best dis-
cover what your community wants — and make sure that thinking is included in
the goals and objectives of the lake management plan.
Watershed management is not lake management. This is an important dis-
tinction because we have discovered that many lakes are not sensitive to phos-
phorus reductions through watershed improvements (see Carpenter et al. 1998,
1999; Newton and Jarrell, 1999; and Osgood, 2000a). Watershed management is
important in three ways:
• First, it's critical in preventing lake eutrophication problems;
• Second, it helps sustain most lake management goals; and
• Third, watershed management also addresses other kinds of pollution.
So, without a sound watershed management element in your lake manage-
ment plans, other strategies and actions are less effective.
Sound watershed management can be approached in three ways (see Chap-
ter 6):
• Point Source Controls. Controlling the pollution discharged
(through pipes) by cities and industry almost always improves lake
conditions (Edmondson, 1991).
• Nonpoint Source Controls. Controlling pollution carried by runoff
improves a lake only when carried out as a long-term, comprehensive
program. Although sustained effects have seldom been demonstrated,
nonpoint source controls stabilize the watershed and minimize the
effects of changing land use.
• Education. Education is often used to encourage behavioral changes
(a significant factor in controlling nonpoint pollution). To be effective,
education programs must address a planning objective with
measurable outcomes. Education can also be a marketing and
community-building tool; both are important for implementing the
management plan (Osgood, 1999c).
atershed >
management is tp lake
management •what
paying your bills is to
financial management.
Both are essential
elements of manage-
ment, but they alone
will probably not help
you achieve your goals.
317
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Managing Lakes and Reservoirs
I I ou would be wise to
[look for a facilitator
skilled and conversant in
rm iiiiiiiiMiiii i 111 11
strategic planning, lake
nanagement, and the
governmental and
regulatory system of
lake management.
J
Developing the Management Plan
To use your resources wisely in developing a management plan, you must know
the essential elements involved and how to put them together.
Getting Organized
V Develop a Work Plan: Planning takes time, effort, and resources. If
you have never prepared a management plan for your lake, much of the
initial management budget will be spent up front on developing the plan.
Use the sample work plan (Table 8-1) to guide the development of the
plan and suggest reasonable expectations for completing it. Keep in mind
that there is no one model: the right model for your lake or reservoir must
be tailored to the specific needs of your lake community.
V Expect Conflict. Conflict is a normal part of human interaction. Any
time you gather people together to discuss their interest in managing a
shared resource, you can expect differing views and positions regarding the
importance, use, value, or investment in that resource. Even when you might
think everyone concurs in their desire to manage or protect a lake, conflict
will erupt over almost every part of developing a management plan.
Rather than working to avoid conflict, it is more effective to man-
age conflict. Look for differing needs and interests, recognize them, and
address them openly and respectfully.
V Use a Facilitator. A neutral facilitator skilled in conflict resolution or
mediation should be used to facilitate the discussion needed to develop
the management plan (Dry, 1993; Fisher et al. 1991). The role of the facilita-
tor is to (I) guide the plan development process in a positive, productive
direction, (2) assure that all participants have an equal chance to voice
their interests, and (3) identify and help resolve conflict when it occurs.
The facilitator will work with the committees, staff, and others to help
them come to consensus regarding significant issues.
You would be wise to look for a facilitator skilled and conversant in
strategic planning, lake management, and the governmental and regulatory
system of lake management.
V Look for Consensus. Robert's Rules of Order can be an impedi-
ment to open discussion and reaching agreements. Voting and other
democratic-like methods (for example, nominal group processes [see
Chapter 3]) may work against consensus. Regardless of how the process is
structured, the outcome of a vote fosters a 'win-lose' environment. While
these processes are quantitatively objective and satisfying, they are psy-
chologically demeaning, especially for the losers. Indeed, those in the
minority often believe that, if only they had better made their case, the
vote would have swung the other way. In the extreme, the minority may
feel that the majority decision was coerced.
You can't always obtain balanced representation, especially with a
range of issues. Thus, unless there is unanimous agreement, there are al-
ways 'losers.' While voting, Robert's and other structured processes have
their place (see Chapter 3). Seeking consensus is best when all parties
need to support and implement the management plan.
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CHAPTER 8: Developing and Implementing a Management Plan
Table 8-1.— Management Plan Development — Sample Work Plan
ACTIVITY
1 . Initial
meeting
2. Organize
3. Develop
work plan &
secure funding
4. Hire a
planner or
facilitator
5. Community
survey
6. Inventory of
lake condition
TIMELINE
Month 1
Months 2-3
Month 3
Month 4-5
Months 6-8
Months 6-8
AGENDA
Assemble interested parties to discuss the
need for managing your lake.
Set up a more formal organization. Identify
committees & committee chairs. Assign tasks
and deadlines. Contact agency staff, local
authorities, and business representatives.
Identify funding needs & sources.
1 . Develop a work plan and timetable. If
you are unsure how to develop the work
plan, ask for proposals.
2. Secure funding. The first planning cycle
will require resources.
Prepare a list of qualifications and scope of
work. Seek candidates.
Develop, implement, and evaluate a
community survey.
Gather & summarize all available physical,
chemical, biological, land-use, ana
demographic information available for your
lake and watershed.
OUTCOME
A resolution to
proceed.
Deadline for
making
decisions to
proceed.
A draft work
plan.
Hire the
planner or
facilitator.
An indication
of community
needs,
interests, and
values.
An objective
picture of the
environmental
condition of
the lake and
its environs.
At this point, it may be necessary to implement a diagnostic study. If it is
apparent that the problems — either real or perceived — lack sufficient physical data for
satisfactory resolution, then a one- or two-year diagnpsfcstudy may be needed. If, on the
other hand, environmental monitoring is required to simply better define an identified problem,
the diagnostic work may be a management action that is an outcome of the planning process. '
7. Preliminary
problem
definition
8. Form
advisory
committee
9. Form
technical
advisory
committee
10. Plan
development
Months 6-8
Months 6-8
Months 6-8
(technical
input may be
needed earlier
in the process)
Months 9+
(6-1 2 months)
(4-12
meetings)
Based on input from the community survey
and the inventory of lake condition, identify
main problems to be addressed in the
management plan.
Based on input from the survey and other
sources, identify community representatives
to serve on an advisory committee. The
size of the advisory committee should be
20 to 30. Extend invitations.
Invite technical regulatory and governmental
representatives to serve on a technical
advisory committee.
Advisory Committee Agenda
- Introductions
- Review survey & inventory summaries
- Educate committee
- Develop vision & goals
- Evaluate alternative strategies & actions
- Decide on management actions
- Develop a monitoring & evaluation plan
- Commit to action
Written
summary of
problems to be
addressed.
- Advisory
committee
roster.
- A specific
charge.
- Technical
advisory com-
mittee roster.
- A specific
charge.
Management
plan
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Managing Lakes and Reservoirs
Seeking consensus allows open expression of all points of view and
agreement on action. This rule for consensus is useful:
If on a particular issue, committee members
disagree, the members do agree that all have been
given an equal chance to be heard and the
consensus agreement represents the best solution at
that time.
Consensus-building is procedurally more cumbersome to administer
and usually more time-consuming, but the result is almost always more
palatable and will lead to willing future action and participation. Consensus
also allows for future reconsideration. If new information becomes avail-
able, the monitoring program finds an unexpected result, or the needs of
the community change, the issue as well as the management response can
be re-opened.
Implementing the Work Plan
The following steps (see Table 8-1) will be required to develop the management
plan. The timelines presented here are meant as guidelines as well as benchmarks
for realistic expectations. Because the ultimate success and effectiveness of your
management plan depend to a great degree on community buy-in, it is better to err
on the side of taking the suggested amount of time rather than looking for short
cuts.
1. Initial Meeting (Month 1)
Most likely, the group has been brought together by a common concern for their
lake or reservoir. The only important outcome of the initial meeting is some com-
mitment to proceed with developing a lake management plan. And this is enough.
2. Organize (Months 2-3)
A more formal oversight committee, sometimes referred to as a Steering Com-
mittee (Interagency Lake C.C., 1996), should be formed to coordinate the devel-
opment of the management plan. This group will be responsible for securing and
administering funding and implementing the work plan to develop the manage-
ment plan; they may even be responsible for adopting and implementing the man-
agement plan.
Identifying working committees and setting them about their tasks is done at
this time. Working committees may include:
• Finance and Administration
• Planning
• Program Management
• Communications and Community Relations
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CHAPTER 8: Developing and Implementing a Management Plan
3. Develop Work Plan and Secure Funding
(Month 3)
A detailed work plan should be developed to guide the development of the man-
agement plan. The work plan has several purposes:
• Project realistic timelines and work loads for developing the plan
• Guide the planner/facilitator
• Serve as a communication tool
Also, funding needs should be identified and funding secured by this time.
You shouldn't proceed beyond this point without enough money to complete the
development of the management plan.
4. Hire Planner/Facilitator
(Months 4-5)
If, in preparing the work plan, the group decides it needs professional assistance,
you or one of your committees can develop a scope of work for the planner or
facilitator. With that in hand, you can seek candidates to hire.
Although your funders or Steering Committee may dictate how you go
about the search, you might want to issue a Request for Proposal, particularly if
you are having difficulty developing your scope of work or your work plan. An
RFP, as it's known, asks candidates to tell you how they would approach this proj-
ect; that will give you several independent ways to think about the project. Be
sure, however, to include your budget in the RFP so responders can stay within
your financial limits.
Look for planners or facilitators who are qualified and experienced in:
• Lake or reservoir management
• Lake and watershed management and regulatory agencies
• Local government
• Mediation and facilitation
The planner or facilitator should also have demonstrated the ability to:
• Be balanced and neutral
• Solve problems and find solutions
• Write and communicate clearly and effectively
• Work with diverse interests
Be sure to ask for and check references!
Although it may be tempting to select someone from a local agency or the
community, think twice! It is critical that the planner be able to facilitate the plan-
ning process as a neutral participant — a local person may have a real or per-
ceived allegiance to one of the interested parties. Your planner/facilitator must
also be experienced with other planning situations to provide broader perspec-
tive and 'out-of-the-box' thinking.
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Managing Lakes and Reservoirs
hen the debate
and deliberations are
conducted in a positive,
respectful atmosphere,
the solutions and
agreements reached are
likely to be sustainable.
5. Community Survey (Months 6-8)
Use the Community Survey to get an overview of the issues and concerns that
must be addressed in the management plan. The response will also help you iden-
tify individuals who can best articulate concerns for their community and who
might be good candidates for the Advisory Committee.
The results of the survey are not meant to give you definitive or quantitative
answers about management issues, but instead should serve as a point of depar-
ture for the work of the Advisory Committee.
The sample (on the following page) is open-ended to allow for full expres-
sion of community concerns. The planner or survey analyst must carefully sum-
marize and interpret the results — maybe even list the written responses.
Remember, you're not looking for definitive results; the purpose of the survey is
to guide the long-term development process. (Chapter 3 gives you a more quanti-
tative survey instrument.)
Deciding who to survey is a critical step. Target individuals and interest
groups who clearly have a stake in the lake and its management; this will give you
better responses (as high as 80 percent is not unusual) than random samples.
Also, a survey designed with specific knowledge of the lake and its management
issues will engage respondents and encourage them to participate in developing
the management plan.
Distribute between 100 to 300 surveys. Because the results will not be ana-
lyzed statistically, this number is determined more by the way it represents the
community. Asking for a short response deadline (1-2 weeks) helps prevent the
forms from getting 'lost in the in-box.' And enclosing a return envelope increases
the returns.
Sometimes follow-up phone interviews can be useful. You will find that peo-
ple who might not ordinarily come forward will, when personally contacted, dis-
cuss — sometimes at length — important concerns. Listening always pays off in
terms of developing a management plan that connects with the community.
Finally, develop a candidate list for the Advisory Committee based on inter-
est expressed by the respondents. The Advisory Committee is the key to con-
necting with the community that will be called upon to implement the plan.
Look for strong spokespeople who represent a cross-section of the commu-
nity as well as those who may espouse single issues or may otherwise be detrac-
tors. The Advisory Committee is the place to bring diverse views together and to
work for their resolution. When the debate and deliberations are conducted in a
positive, respectful atmosphere, the solutions and agreements reached are likely
to be sustainable.
6. Inventory of Lake Condition (Months 6-8)
Gather all available information about your lake and prepare an inventory. Every
objective bit of information is fair game here. This includes physical, chemical, so-
cial, historical, political, commercial, and management information. Using the re-
sponses from the community survey, you can gauge what information is more or
less important to your community.
The inventory should include both historic and contemporary information
and be reported in a concise and readable format. This should not be a detailed
322
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CHAPTER. 8: Developing and Implementing a Management Plan
Sample Community Survey
I. Personal Information
a. How long have you lived in or conducted business in the Pretty Lake
community?
b. The next phase of the lake planning project will involve an advisory
committee to help focus the management plan. Are you interested in serving
on the Advisory Committee?
c. Are you aware of anyone else whose input would be important? If so, please
give their name.
d. Please include your name, address, and phone.
II. Uses and Values of Pretty Lake
a. Describe your recreational use(s) of Pretty Lake.
b. What about Pretty Lake is valuable to our community?
c. What about Pretty Lake and its environs are of aesthetic or environmental
value to you?
d. What uses conflict with or detract from how you use or value Pretty Lake?
e. What uses should be regulated?
III. The Condition of Pretty Lake
a. How do you perceive the overall water quality of Pretty Lake?
b. How do you perceive the quality of the fishery in Pretty Lake?
c. How do you perceive the quality of aquatic plants in Pretty Lake?
d. How does the condition of Pretty Lake add to or detract from how you use or
value the lake?
IV. Issues and Concerns
a. What are important issues and concerns for the management of Pretty Lake?
b. What is the most important issue?
c. What areas of conservation are important to you?
d. What concerns do you have about the management (or lack of management)
in Pretty Lake?
V. Other Comments. Please take this space for any other comments.
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Managing Lakes and Reservoirs
engineering report, but rather a basic summary that describes the condition of
the lake in the context of past changes, regional perspectives, and predominant
uses and values.
Include a summary of the following categories, including only the detail nec-
essary to characterize the lake's condition in a format that the Advisory Commit-
tee can use:
• Physical and Chemical. Lake basin dimensions, basic chemistry,
oxygen regime, mixing patterns, nutrient concentrations, historic
comparisons.
• Lake Condition and Trophic State. The three trophic state
variables — phosphorus, chlorophyll, and Secchi disk — and their
relevance.
• Fish. Population assessments, gamefish, stocking, and management
programs.
• Aquatic Plants. Predominant species, their distribution, importance
to the lake ecosystem, and management and control programs.
• Shoreline Environment. Stabilization structures, areas of erosion,
plant communities.
• Exotic Species. Those that are present or may infest the lake.
• Watershed. A map and description that includes points of inflow and
point sources of pollution.
• Land Use arid Population. Historic, present, and projected land use
as well as population and settlement patterns.
• Lake Uses. Recreational, wildlife, aesthetic, and commercial
categories.
• Planning and Zoning. A zoning map that describes planned uses and
development patterns.
• Conservation Holdings, Parks, and Public Lands.
• Commercial and Business Interests. Businesses in the community
that receive some income from the lake, waterfront commercial
establishments, or the operational plan of a reservoir.
• Management and Control. Individuals, agencies, and organizations
with management, permitting, and control authority, including past,
present, or proposed control efforts.
• Diagnostic-Feasibility Studies. A federal Section 314 (Clean Lakes)
or similar study either completed or currently ongoing.
Because the Advisory Committee will use this report to get up to speed
quickly, it should contain enough information in a readable format to help them
understand the lake's condition. And they should be able to read and understand
it in less than an hour.
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CHAPTER 8: Developing and Implementing a Management Plan
7. Preliminary Problem Definition (Months 6-8)
Before the first Advisory Committee meeting, prime their strategic thinking by
offering your (or your planner's) assessment of the main problems confronting
this community. This shows that you are in tune with the community and will get
your planning effort off to a good start. Remember, however, to present this as
your best shot — the final assessment is the Advisory Committee's to make. See
example from White Bear Lake, Minn, (below).
Directions for Management Planning
Iased on the survey and the assessment of lake conditions, several concerns re-
quire attention by the Advisory Committee:
• White Bear Lake is a highly valued resource, providing aesthetic,
recreational, commercial, and wildlife qualities that ought to be protected
and preserved. But certain lake uses threaten or conflict with these values:
—Surface uses that lead to congestion and are noisy
— Commercial activities, public access, over-development
-r-lce fishing houses (litter/sanitation), motor boats (gas/oil)
—Uses that ar,e unsafe or incompatible with other uses
• Aquatic plants are generally not a nuisance and serve the lake by
providing fish and wildlife habitat and water quality benefits. Eurasian
waferrhilfoil has not yet become a nuisance, but may someday.
• Pollution from the watershed — such as stormwater runoff, lawn chemicals,
and on-site septic systems — is or could become excessive,
.1
• The history of large lake level fluctuations is a concern. No plan is in place
t_ to control lake levels.
• There is concern regarding the leadership and direction provided by the
White Bear Lake Conservation District.
Preliminary problem definition from Osgood (1999a]
8. Form an Advisory Committee (Months 6-8)
The Advisory Committee connects the planning effort with the lake community.
Although they will be responsible for developing a meaningful management plan
for your lake that addresses real needs and values, the ultimate solutions to man-
aging your lake have more to do with connecting with the community than with a
particular engineering or biological approach. Thus, it is essential that the Advi-
sory Committee represent the entire community — who they are and how they
are selected is critical.
A committee of 20 to 30 people is recommended. More than 30 may pose a
challenge for effectively managing the plan development process. However, if you
are flooded with willing participants, it is a worthwhile trade-off to be as inclusive
as possible. At a minimum, invite people representing:
• Lakeshore homeowners
• Community residents
• Businesses
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Managing Lakes and Reservoirs
I he basic charge to the
Advisory Committee is to
develop the manage-
ment plan and to
recommend its adoption
and implementation.
.
• Elected and appointed officials
• Users and user groups
• Community organizations
• Environmental and conservation organizations
« Historic societies
The Steering Committee is sometimes tempted to invite people with techni-
cal training to sit on the Advisory Committee because they "get it." This tempta-
tion stems from the concern that a citizens committee will not come up with the
correct approach, so "techies" will help them along. Experience has shown the
opposite to be true — citizens demonstrate an impressive grasp of relevant lake
management issues as well as the ability to focus their attention on positive,
workable solutions. Thus, resist this temptation; the Advisory Committee can
turn to the Technical Advisory Committee when they need such advice.
The basic charge to the Advisory Committee is to develop the management
plan and to recommend its adoption and implementation. The simple rationale
for this is that the committee and the community they represent will be called
upon to implement the actions they recommend in the management plan, so they
should be the ones to direct the process. Prepare a written charge and ask the
committee if this is agreeable at their first meeting.
Don't be concerned that the Advisory Committee will "take over" — in fact,
any inclinations they have to direct the process should be encouraged. The Advi-
sory Committee will appreciate the support of the Steering Committee and the
planner/facilitator.
While the committee members were selected on the basis of how they rep-
resent various interests, you should make it clear that they are not expected to
represent any specific interest, but instead represent their own best judgment.
9. Form a Technical Advisory Committee (Months 6-8)
The Technical Advisory Committee provides technical and regulatory oversight
to the development of the lake management plan. This committee interacts with
the Advisory Committee as needed to assure the technical soundness and ade-
quacy of the planning process by making it consistent with lake management sci-
ence and regulatory requirements.
The Technical Advisory Committee may meet regularly or in response to
the needs of the Advisory Committee. It is important to clearly distinguish the
functions of the two.
10. Plan Development (Months 9+)
The main work — and the fun work — begins here. The agenda for the Advisory
Committee is to develop the management plan according to the steps in the plan-
ning cycle (see Blue Water Commission example). This process may take from six
to 12 months and involve four to 12 meetings. Meetings will normally be a mini-
mum of two hours in duration, but should not be longer than four hours.
Determine the agenda in advance and keep to it. This is important because it
demonstrates your appreciation and respect for the significant commitment by
these volunteer members. Remember, planning is an ongoing process and it is
okay to save some concerns for another time.
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CHAPTER 8: Developing and Implementing a Management Plan
Now it is a matter of completing the management plan. The basic strategy is
to start big and work smaller. This means begin with a simple problem statement,
agree upon a vision, set goals, evaluate and decide upon management actions with
measurable objectives, and provide for ongoing monitoring and evaluation.
Elements of the management plan, taken directly from the planning cycle
model (see Fig. 8-1), are repeated here to emphasize how to use the work plan to
complete the management plan. These steps also serve as a framework for the
contents of your management plan document.
• Step 2: Analyze the situation, take stock. This is a report that
has been prepared in advance and presented to the Advisory
Committee before their first meeting. The report is the basis for the
initial problem and vision statements — the Advisory Committee
must agree on both early in the process.
r
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33*
rfjNov. 15
f Dec. 2
H Dec. 16
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irjan. 6, 1998
tm---
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Blue Water Commission
MEETING SCHEDULE
1 ' • " • . • _.•"'•••. •
(Two-hour meetings, except day-long workshop)
Introductory meeting. Welcome; committee charge; committee
structure & process.
Workshop. Introduction to lakes and watersheds; historical context;
preliminary goal setting; vision. ;
Resource speakers. Lake condition; What is the deal with
phosphorus?
Resource speakers. Aquatic plants; fish; fish contamination.
Resource speakers. Urban watershed management; watershed
management authorities.
Resource speakers. Setting realistic goals; education programs.
Goals. Report from the Technical Advisory Committee; preliminary
discussion of goals. -......•
Goals. Continued discussion. .',• ..•.-.
Diagnostic study. Presentation of the diagnostic study results by
the Technical Advisory Committee.
Management approaches. Report from the Technical Advisory
Committee.
Management approaches. Setting targets and considering
management alternatives.
ilApr. 21 Consideration of management targets and actions.
f2'— — • Review draft chapters of report. :
^Tv\ay13
£May 27
U (from Osgood,
Consider Draft Report. Review Feasibility Report and
recommended management actions.
Final meeting. Wrap up.
7998;
he basic strategy Is to
start big and work
smaller. This means
begin with a simple
problem statement,
agree upon a vision, set
goals, evaluate and
decide upon manage-
ment actions with
measurable objectives,
and provide for ongoing
monitoring and
evaluation.
327
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Managing Lakes and Reservoirs
• Step 3: Set directions — vision, goals, and objectives. Again,
work from big (vision) to small (objectives). This is a systematic,
deliberative process. Resist the temptation to talk about goals before
there is consensus on the vision. Likewise, don't move on to
management actions and objectives until there is consensus on goals.
The facilitator and the Technical Advisory Committee play key roles in
making sure the discussion stays on track and the outcomes are
reasonable.
• Step 4: Evaluate alternative strategies and actions. This
process assesses the feasibility and balance of all possible approaches
and technologies that can help reach your management objectives.
Evaluate feasibility on technical, financial, political, and other factors.
Also, consider fees, permits, or other requirements. Weigh all
alternatives, one against another, to assure they work to complement
rather that conflict with a common goal. Normally, management
actions fall in the categories of plans, policies, programs, or projects.
• Step 5: Take action; implement. The management plan prescribes
management actions. Be sure that a recommended action will take
place before putting it in the plan by answering such questions as, "Is
there a reliable funding source available?" or "Has the agency
expected to implement the recommendation expressed the willingness
to do so — do they have the authority?"
• Step 6: Monitor and evaluate progress. A program to monitor
the performance of management actions is essential to the long-term
success of your management program. The purpose of the monitoring
program is to track progress as well as to have objective information
that may be required to adjust your management program. You can
always expect to make adjustments when you're working in the
natural environment. See Wedepohl et al. (1990) for a technical
reference and Simpson (1991) for guidance for volunteers.
• Step 7: Do it again. Provide for ongoing planning. At a minimum, a
management organization should be identified or created to oversee
the ongoing management of your lake.
Implementing the Plan
Meaningful, effective, and positive management action requires a plan — which
you now have — and an organization with the resources to carry it out.
The Management Organization
The management organization will make the plan work and take over the ongoing
planning cycle (see Fig. 8-1). It should be locally based so it can focus community
resources on implementing the management plan.
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CHAPTER 8: Developing and Implementing a Management Plan
Types of Organizations
To find the right organization to manage your lake, consider several factors:
• The geographic extent of your lake and watershed
• The existence of an appropriate organization
• The management and oversight needs identified in your lake
management plan
• The resources available in your community
• How to most effectively sustain your management program
Management organizations include these categories:
• Governmental: Various intragovernmental programs that can fold
the administration of a lake management plan into an existing
framework; special units of government or assessment districts; or
special legal arrangements.
=> Existing programs in a federal, state, or local agency
=> Lake Improvement District
=> Watershed District
=> Soil and Water Conservation District
=> A joint powers agreement
• Non-governmental: Organizations organized formally or informally
with powers and authorities ranging from voluntary compliance to
legal incorporation.
=> Nonprofit Corporation
=> Lake Association
=> Partnerships
From the Management Plan of the
Blue Water Commission (Osgood, 1998)
Action #10. Identify or create an entity to champion the goals and
"recommendations of the Blue Water Commission.
•-The principals agree to do this by: ":..
• Formally organizing with a mission compatible with the
Blue Water Commission's goals.
• Including in the mission coordinating, facilitating, and advocating the
.._•.. Blue Water Commission's recommendations.
* Identifying and securing funding necessary to protect the lakes.
' -; • Providing the resources needed to sustain their effort.
• Monitoring, evaluating, and reporting progress toward! accomplishing their
goals. -: -\; ' ~ '".,'.''". : ••• .:. ' , "• "..'• ••';;. -.-.'' '•.'''..•':••
* Amending this plan in response to evolving community values,
developments in lake and watershed management technologies, and
changes in the environment in and around the two lakes.
329
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Managing1 Lakes and Reservoirs
o be effective and
-lasting/ your lake
^management
^organization should be
i locally-based and
[focused only on
rmanaging the lake: this
^requires clear vision and
ta sound organizational
iand development
plrgfegy. You must pay
t s '
{attention to your
^management
(organization and invest'
Lin its success.
he basic funding for
inn mini n g i in unit _• i i • •
operating and admini-
stering the organization
must come"from the
Jocal community.
Keys for Effective Organizations
To be effective and long-lasting, your lake management organization should be
locally-based and focused only on managing the lake: this requires clear vision and
a sound organizational and development strategy. You must pay attention to your
management organization and invest in its success.
In their book, Profiles of Excellence: Achieving Success in the Non Profit Sector, the
authors cite four "Hallmarks of Excellence" for building effective nonprofit or-
ganizations (Knauft, et al. 1991; see also Hummel, 1997):
I. The Primacy of Mission. A clear sense of mission with goals to carry
out that mission are essential. Everyone in the organization should be
aware of and agree with the mission, and make the mission come alive
as they go about their respective jobs.
2. Effective Leadership. "The best leaders embody the organization's
mission — they can clearly articulate it and translate it to others with a
sense of excitement." There are many leaders in an organization, ranging
from the Board and Chief Executive Officer to staff and volunteers.
Normally the CEO is looked upon for day-to-day leadership in carrying
out the organization's mission.
3. A Dynamic Board. A board should represent the interface between
the community and the organization. A dynamic board represents the
diversity of the community, has varied skills, relates well among its
members, and is committed to the organization.
4. Strong Development Program. The ability to attract and sustain a
sound and diverse financial basis to run the organization takes work.
This work is most effective when shared between the board and staff.
Relying exclusively on one or the other is risky.
The board is critical to the success of your management organization.
Their role should include:
• Budget and Finance
• Strategic and Annual Plans
• Fundraising
• Human Resources
• Community Relationships
• Program Evaluation
• Board Development
• Advising Staff
Funding and Assistance for Lake
Management Organizations
To sustain a meaningful and long-lasting management effort, your lake manage-
ment organization will require funding and assistance. As a practical matter, the
basic funding for operating and administering the organization must come from
the local community.
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CHAPTER 8: Developing and Implementing a Management Plan
Numerous funding programs and sources are available for start-up funds,
planning and feasibility studies, special projects, and implementation programs.
Use this list as a starting point:
^ Federal Agencies. Funding programs, appropriation levels, and pro-
gram requirements change frequently. U.S. EPA's Catalog of Federal Funding
Sources for Watershed Protection, now in its second edition (1999), contin-
ues to offer the most up-to-date information on federal funding — check
EPA's web site: www.epa.gov\owow\watershed\wacademy\fund.html.
• U.S. Department of Agriculture: Grants and loans are available
from most USDA agencies, including:
=> Farm Services Agency
=> Cooperative Extension
=> Farmer's Home Administration
=> Forest Service
=> Natural Resources Conservation Service
• The Economic Development Administration of the
Department of Commerce makes loans and grants.
• U.S. Environmental Protection Agency has numerous programs
authorized through the Clean Water Act. Historically, the Clean Lakes
Program used Section 3 14 grants administered by states to help public
lakes; today, that funding can come through Section 319 (nonpoint
source). Contact your state environmental agency for information.
• The Department of Housing and Urban Development
supports a broad range of planning and management activities.
• Department of Interior agencies make grants available through:
=> Office of Surface Mining Reclamation and Enforcement
=> Bureau of Reclamation
=> Fish and Wildlife Service
• U.S. Geological Survey helps states through cooperative programs.
V State and Local Agencies* Many state and local governments sup-
plement or complement federal funding programs. Your Technical
Advisory Committee members should know about these sources.
v Other Sources.
• Foundations. These are organizations — both private and corporate
— set up to give away money. They're listed by type of giving in The
Foundation Directory (for information, see the Foundation Center's web
site at www.fdncenter.org). You could set up your own foundation to
fund your management program; but this will dilute the focus of your
management program, and might eventually sever the connection
between the community and the lake they want to protect.
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Managing Lakes and Reservoirs
• Corporations. These are usually direct giving programs, usually with
a strong tie to the community served by the business.
• Membership Dues. Member dues normally fund the costs of
supporting your members, such as mailings, newsletters, etc., but not
programs or projects. Multiple membership levels — such as becoming
a Bald Eagle for $5,000 — is one way to increase giving levels, nurture
individual gifts, and begin to support management programs.
• Membership Organizations. Service clubs, fraternal organizations,
chambers of commerce, women's and men's groups, and many other
groups often contribute financially to a resource they value.
• Individuals. Substantial gifts usually require a great deal of time
invested in nurturing the individual. This can include planned giving
through estate planning.
• Volunteers. Volunteers will likely be a significant source of assistance.
Be sure that you have a volunteer coordinator to assure that
volunteers are used effectively.
Other Considerations for Management
Organizations
if.
however, you are
^creating a new
muni in, «F N j as..^.,! n n,,,li ,„ ,H,»,,ii ,, ft,
organization or
^assigning an existing
^organization significant
•« II I I ! !"" '!'}"";'I"5-t' *'" "
new responsibilities,
pfign you need to' make
'sure it has the capacity
Jllll'll !l I ! ! I lll«Hl(iplll ! II I"1
and resources to do the
,
Other considerations include administrative and oversight functions required to
manage programs, personnel, contractors, grants, and so on. If an existing organi-
zation is going to implement the management plan, then they will probably already
have these systems in place.
If, however, you are creating a new organization or assigning an existing or-
ganization significant new responsibilities, then you need to make sure it has the
capacity and resources to do the work. These areas should receive particular at-
tention:
• Personnel Management. This includes hiring (and firing),
supervising, managing, directing, and coordinating staff.
• Managing Consultants and Contractors. This involves writing
requests for proposals or qualifications, interviewing, managing and
directing, oversight, and contract management.
• Permits and Regulations. Many watershed and lake management
projects require permits or have regulatory restrictions. As you
develop the management plan, the Technical Advisory Committee
should be advising you on applicable regulations and permits.
• Community Relations. Staying connected with the community who
use and value the lake managed is key to effective long-term
management.
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CHAPTER 8: Developing and Implementing a Management Plan
What Next?
Go. Do not feel you must abide by every detail in this chapter as you prepare
your management plan. Take what works and what your lake needs, then run with
it. As my father used to say, "Let's do something, even if it's wrong" With common
sense and these guidelines, planning for the management and protection of your
lake or reservoir cannot go wrong.
References
Carpenter, S.R., N.F. Caraco, D.L Correll, R.W. Howarth, A.N. Sharpley, and V.H. Smith
1998. Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecol.
Appl. 8:559-68.
Carpenter, S.R., D. Ludwig, and W.A. Brock. 1999. Management of eutrophication for
lakes subject to potentially irreversible change. Ecol. Appl. 9(3):751-71.
Edmondson, W.T. 1991. The Uses of Ecology: Lake Washington and Beyond.
University of Washington Press, Seattle and London.
Environmental Ground. No date. The State of Watershed Water-Quality
Management in Minnesota. Environmental Ground, Inc., and the Minnesota
Association of Watershed Districts.
Fisher, R., W Ury, and B. Patton. 1991. Getting to Yes: Negotiating Agreement
Without Giving In. Penguin Books, New York.
jeppesen, E.,J.P.Jensen, M. Sondergaard, T. Laurridsen, LJ. Pedersen and L.Jensen.
1997. Top-down control in freshwater lakes: The role of nutrient state,
submerged macrophytes and water depth. Hydrobiologia 342/343: 151-64.
Hummel, J.M. 1997. Starting and Running a Nonprofit Organization. 2nd ed. University
of Minnesota Press, Minneapolis.
Interagency Lake Coordinating Committee. 1996. Developing a Lake Management
Plan. Minnesota Board of Water and Soil Resources, Minnesota Department of
Natural Resources, Minnesota Pollution Control Agency, Minnesota Department
of Agriculture, St. Paul.
Kehler, R., A. Ayvazuan, and B. Senturia. No date. Thinking Strategically: A Primer on
Long-range Strategic Planning for Grassroots Peace and Justice Organizations.
The Exchange Project of the Peace Development Fund, Amherst, MA.
Klessig, L., B. Sorge, R. Korth, M. Dresen, and J. Bode. No date. A Model Lake Plan for
a Local Community. Wisconsin Lakes Management Program, Madison. (Reprinted
in this manual as Appendix 3-A.)
Knauft, E.B., R.A. Berger, and S.T. Gray. 1991. Profiles of Excellence: Achieving Success
in the Nonprofit Sector. Jossey-Bass Publications, San Francisco.
MacKay. H. Column. United Features Syndicate, Chicago.
Metropolitan Council. 1997. Lake McCarrons wetland treatment system — Phase III
study report. Metro. Counc. Environ. Serv. Publ. No. 32-97-026, St. Paul.
Moss, B., J. Madgwick, and G. Phillips. 1996. A Guide to the Restoration of
Nutrient-enriched Shallow Lakes. Braods Authority, Norwich, Norfolk, UK.
Newton, B.J. and W.M.Jarrell. 1999. Procedure to estimate the response of aquatic
systems to changes in phosphorus and nitrogen inputs. Natl. Water Climate
Center. U.S. Dep. Agric., Washington, DC.
333
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Managing Lakes and Reservoirs
Olsen Thielen Co. Ltd. 1998. Planning ahead ... Strategically. O&T Advisor: May/June.
www.olsen-thielen.com
Osgood, D. 1988. The Limnology, Ecology and Management of Twin Cities
Metropolitan Area Lakes. Metro. Counc. Publ. No. 590-88-123, St. Paul, MN.
. 1992. Managing Minnesota's Lakes: A Report of the Minnesota Lake
Management Forum. Freshwater Foundation, Wayzata, MN.
. 1995. Christmas Lake Management Plan. Christmas Lake Ass. and
Ecosystem Strategies, Shorewood, MN.
. 1996a. Lake McCarrons: Strategic Management Plan. Prepared for Ramsey
County and the Lake McCarrons Neighborhood Association by Ecosystem
Strategies, Shorewood, MN.
-. !996b.The ecological basis for lake and reservoir management. Lake Line
16(2).
. 1998. Blue Water Commission: Report and recommendations for the
management of Lake Nokomis and Lake Hiawatha. May 1998, Minneapolis.
. I999a. White Bear Lake Management Plan: Report and recommended
actions of the Advisory Committee. White Bear Lake Conservation District and
Ecosystem Strategies, Shorewood, MN.
. !999b.The phosphorus paradigm. Lake Line 19 (2).
. I999c. Putting education in lake plans. Lake Line 19(3-4):50-1.
. 2000a. Lake sensitivity to phosphorus changes. Lake Line 20(3):9-11.
. 2000b. Mooney Lake Management Plan. Mooney Lake Ass. and Ecosystem
Strategies, Shorewood, MN.
Simpson,J.T. 1991. Volunteer Lake Monitoring: A Methods Manual. EPA 440-4-91 -002.
Office of Water, U.S. Environ. Prot. Agency, Washington, DC.
Ury, W. 1993. Getting Past No: Negotiating Your Way From Confrontation to
Cooperation. Bantam Books, New York.
U.S. Environmental Protection Agency. 1990. Monitoring Lake and Reservoir
Restoration: Technical supplement to the Lake and Reservoir Restoration
Guidance Manual. EPA 440/4-90-007. Washington, DC.
. 1997. Top 10 Watershed Lessons Learned. EPA 840-F-97-001. Office of
Water, Washington, DC.
-. 1999. Catalog of Federal Funding Sources for Watershed Protection. EPA
841 -B-99-008. Office of Water, Washington, DC.
Walesh, S.G. 1999. DAD is out, POP is in. J. Am. Wat. Resour. Ass. 35:535-44.
Wedepohl, R.E., D.R. Knauer, G.B. Wolbert, H. Olem, RJ. Garrison, and K. Kepford.
1990. Monitoring Lake and Reservoir Restoration. EPA 440/4-90-007. Prep, by N.
Am. Lake Manage. Soc. for U.S. Environ. Prot. Agency, Washington, DC.
Wilson, B. 1998. An analogy illustrating the importance of planning for Lakes.
Minnesota Pollution Control Agency, St. Paul.
334
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CHAPTER 9
Lake Protection and
Maintenance
When it comes to lake protection and maintenance, the old adage, "an
ounce of prevention is worth a pound of cure," is good advice. If your
lake association has recently completed a restoration effort, you know
that preventing pollution and its negative effects on the lake is easier to achieve,
and much less expensive. If your lake is still in good shape then this chapter can
help you keep it that way or even improve it.
People are attracted to water like magnets to steel. Fishing, swimming, boat-
ing, hiking, watching the sun set over the water, just sitting on the shore — all
make waterfront property very desirable, and increasingly valuable. But enjoying a
lake also means caring for it; with the pleasure offered by the lake comes the re-
sponsibility for protecting those uses. Although this chapter describes many ap-
proaches for assuming that responsibility, the key to lake protection and
maintenance is public involvement and organization.
Forming and Enhancing Lake
Organizations
Lake Associations: Roles, Benefits,
and Activities
Whose responsibility is it to protect and maintain the water quality of a lake —
lake residents, lake users, government, or local businesses? Not surprisingly, the
answer is all of the above. Each of these lake interests contributes in different
ways to protecting the lake.
A lake association is one of the most important tools available to lakefront
residents. Many lake associations are organized in response to a lake crisis such as
nuisance weeds, declining fisheries, or foul odors. People find they can accomplish
more as an organized group than they can individually, and this rationale holds
true for lake protection and maintenance.
Lake associations play many different roles:
« They bring together a group, usually of lake property owners, to
maintain the lake.
335
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Managing Lakes and Reservoirs
flhe^WaJloon^Lake
"Association in the
•northwest Lower
[Peninsula of Michigan
has a governmental
meets regularly to
discuss local government
activities and how they
Jmay affect the lake and
|ts watershed. They also
organize special
breakfast meetings,
all local ""
jovernment officials to
iscuss topics of interest
to the lake association
such as stormwater
management or
pnovative zoning
approaches. This
committee has fostered
excellent communication
between the association
|l *. ,.MM.,.r.OT
and government
officials. In fact, some of
the lake association
r_ i -
members are now
members of planning
Ifommissjons or
ttownship boards.
Participants in a watershed tour listen attentively to their guide.
• They monitor and maintain water quality.
• They monitor activities that may harm the lake.
• They influence and participate in local government activities.
• They are an information source and can play an important social role.
• They advocate proper management and prevent activities that harm
the lake.
• They educate lake residents and the public.
• And, perhaps most important, they inform and involve people in lake
management decisions.
The more informed people are about lake problems, alternative management
techniques, and watershed dynamics, the more thoughtful their decisions will be
when selecting and implementing appropriate protection and maintenance proce-
dures.
As with any organization, volunteers must be involved from the beginning.
Many lake associations have retired professionals, such as lawyers or accountants
who can help with setting up the bylaws, filing for nonprofit tax-exempt status,
and electing a board.
Most lake association funding comes from memberships of lake residents and
lake users. Building and maintaining a membership can involve significant work such
as developing mailing lists of lake property owners and listening and acting on
members' concerns. Sponsoring special projects such as a water quality study may
require funding above and beyond membership contributions; this means special
fundraising. Many references are available to help nonprofits with fundraising.
336
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CHAPTER 9: Lake Protection and Maintenance
Getting involved in local and statewide government is a very valuable role for
lake associations. Zoning/planning commissions make land-use decisions that can
affect lakes; If lake association members attend these meetings they can influence
decisions in a way that benefits the lake. Road and transportation commissions,
county boards, drain commissioners, and other governmental offices also make
decisions that can affect lake management.
It is even more important to foster these relationships where lake residents
are primarily seasonal, as it helps permanent residents value the help of lakeshore
property owners year-round.
Getting to know state and federal representatives is also important. State
and federal government programs fund most large lake projects. Meeting with
those people who represent the lake's district can help insure that funding, pro-
grams, and staff are available to help with lake concerns.
Isn't meeting with elected officials lobbying, and therefore illegal under non-
profit tax-exempt law? The answer is no. Most lake associations educate rather
than lobby. They meet with their representatives to inform them about the asso-
ciation's goals and activities and share the association's concerns and desires for
legislation.
If, however, a nonprofit organization classified as 501 (c)(3) decides to lobby,
it must file a 501 (h) with the IRS. That gives the organization the ability to spend
no more than 20 percent of its time and budget on lobbying. Lobbying is defined
as communications intended to influence specific legislation. In other words, to
* Bylaws, incorporation, tax-exempt status •— these legal buzzwordsvwill
338 become everyday words to members of a new lake association; A steering :
pj=wcommittee should develop the articles of incorporation, bylaws, and application for
^T jgxrexempt status. For assistance, contact other lake associations and attorneys who
-Jive on the lake. Tips on developing these legal documents:
^•Articles of Incorporation: Legal papers that form an organization filed with a
state. Makes the group a legal entity and may protect individual members from
= liability.
" • Bylaws: Details that state how the organization functions; e.g., its purpose,
board structure, membership and annual meeting requirements, what makes a
quorum, how decisions are made.
• Tax-exempt Status: The Internal Revenue Service reviews applications,
articles of incorporation, and bylaws to determine if an organization should be
" granted this status; the most relevant to lake associations is the 501 (c)(3). This
exempts the organization from having to pay some taxes and allows it to solicit
- "tax-deducfjble cpntribijtion,?;. For,qn organization to receive and maintain
~ tax-exempt status, its activities must be beneficial to society and serve a function;
that would otherwise have to be done by government. For example, a lake
_ association with,g goal and activities directed toward protecting property values
" for riparians will not likely receive tax-exempt sttitus. However, a lake association
with, a goal and activities directed toward protecting water quality for public and
""private recreational uses wqujd most likely receive the status. A tax-exempt status
may bring discounts from certain retailers and other service providers, and also
makes an organization eligible for many grants or other funding sources. Being a
~ 501(c)(3) tax-exempt organization limits the amount of lobbying a group can do.
337
-------
Managing Lakes and Reservoirs
discuss a bill or a ballot proposal with a government official is lobbying. Educating
government officials on lake management issues is not considered lobbying.
The opportunities for lake associations are virtually limitless. It may be as
simple as holding informal meetings of homeowners to share information about
the lake or as complicated as monitoring the passage of enabling legislation to
form special districts to protect and improve lakes. Some ideas your lake associa-
tion may want to try:
• Publish a newsletter for lake residents.
• Distribute educational materials about shoreline property
management.
• Sponsor field trips to explore the lake's ecosystem by canoe or
motorboat.
• Organize a watershed tour to promote understanding of polluted
runoff and watershed features.
• Work with local schools to sponsor a special program for students
on your lake.
Boyne City, Mich., students experience what happens on Lake Charlevoix as they use
EnviroScape® (a watershed model) to learn how to prevent water pollution.
338
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CHAPTER 9: Lake Protection and Maintenance
Water Quality Monitoring
• Participate in volunteer lake monitoring programs.
• Organize volunteers to implement followup monitoring from
restoration activities.
• Develop a water quality monitoring program for the larger streams
that enter your lake.
• Work with government, universities, and other groups to accomplish
special lake studies.
• Encourage all lake residents to monitor for exotic species.
Recreation
• Work with fish specialists to conduct a creel survey.
• Conduct boat survey of residents and public users.
• Maintain bulletin boards at public access sites with information on
special rules, fishing regulations, etc.
Organize lake association members to attend local government
meetings to monitor activities and influence decision-making.
Meet with state and federal representatives to let them know about
the lake association's goals, any needs for improved administration of
existing laws, new legislation, funding, etc.
Write letters to inform government representatives about lake issues.
Comment on proposed activities that may harm the lake and its
ecosystem, such as dredge and fill permits.
Community and Social
• Organize a picnic or barbeque that follows an association meeting.
• Coordinate a sailing club or fishing contest.
• Sponsor special events to recognize volunteers and celebrate
successes.
Lake Districts
Some states give lake districts authority to raise money and implement projects
to restore and improve lakes. The activities they can fund vary with each state's
enabling legislation. Wisconsin lake districts, for example, have the power to tax,
levy special assessments, borrow and bond to raise money, and implement proj-
ects such as weed control to protect and improve their lakes.
Generally, lake district boards must have representatives from all local units
of government (county, township, and city or village), the lake association or a lake
resident, the road commission, the drain commissioner, and the state environ-
mental department that oversees lake activities.
339
Learn from History Tip:
There once was a beautiful
lake in Michigan where
many of the residents thought
the lake level was too high
and others thought it was too
low. Each group formed their
own lake association: the
High Level Association and
the Low Level Association.
They fought expensive court
battles until a legal decision
determined in favor of the
low lake level. A few years
later both lake associations
dissolved and now the lake
is without any organized
group working to protect it.
The moral of the story —
don't let one issue dictate the
entire purpose of your
association; work together,
even if you disagree about
what is best for the lake.
-------
Managing Lakes and Reservoirs
Nine Steps to Forming
Association
If your lake does not have a lake association, identify several people who share your
. interest and form one! An active lake association will do wonders for your lake.
1. Develop a steering committee: Invite interested individuals to a meeting to dis-
cuss organizing a lake association. If your lake currently has a problem and people
' ^ have different ideas on how-to solvei 'itt.mgkeisure all views arejepresented.
2. Brainstorm Goals and Objectives: Develop a vision for all the things that the
; lake assoiciation
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CHAPTER 9: Lake Protection and Maintenance
Historically, lake districts have been used primarily for lake restoration pro-
jects. Lake boards make funding a project equitable among lake residents. Because
the process creates a new governmental entity it also dictates public notice of
meetings, public hearings, and other avenues for public participation.
On large lakes with multiple governmental jurisdictions, lake boards provide
a valuable tool to manage a large lake improvement project.
Lake boards are often organized around a lake problem, but lake residents
may differ on the best way to solve it. To limit controversy, try to ensure that
both sides are represented on the lake board. The board may also lack full com-
munity support because many people refuse to support any additional govern-
ment board or agency. Just remember — as with any lake management tool, lake
districts can be extremely effective if used appropriately.
Where to Go for Help
Many resources are available to help lake associations get started and stay active
(see the reference section). However, help may be next door. Perhaps another
lake near you has a lake association. Most groups are more than willing to share
their successes with others.
Other important community resources include Cooperative Extension of-
fices, local conservation and environmental groups, conservation districts, and
universities.
The information super highway is now one of the most efficient and effective
ways to access information. Unlike a passing fad, the internet is like the radio of
the '30s and the television of the '50s.
Merging onto the information highway requires a computer and a modem. If
you have neither, you can probably use a computer at the library or university. But
if you just need some help getting started, look for an instructional book or con-
tact a local internet service provider.
Internet information is accessed through search engines in two ways: (I) by
opening browser software and going directly to a website address (usually starts
with www.) or (2) by searching for specific information using a search engine. Ya-
hoo.com, MSN.com, and Netscape.com are good places to start since they all con-
nect to other search engines. Be aware the search engines operate differently and
they do not always find everything that is out there.
Since the information is always changing on the internet some of the govern-
ment home pages provide stable locations with sound information on lake man-
agement; plus, they also have links (direct connections) to other related sites.
Browser programs, such as Netscape and Internet Explorer, let you mark the lo-
cation of your favorite pages with a "bookmark" that allows you to go directly
back to a particular web page once you have visited it.
Some lake web sites worth visiting include:
• wvvw.epa.gov/owow/lakes/ — EPA's Office of Wetlands, Oceans, and
Watersheds (it has many interesting links)
• www.nalms.org — North American Lake Management Society
• www.terrene.org — Terrene Institute
• www.worldlakes.org — LakeNet Program
Internet Lingo:
• Search Engine: software
that scans the internet for
sites that contain key
words or phrases that
you provide.
• Browser: interfacing
software that allows you
to navigate through the
internet by pointing,
clicking, and typing.
• Plug-ins: additional
software (often included
with the browser) that
allow you to hear sound
and see animation and
video.
341
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Managing Lakes and Reservoirs
The web isn't just a source of information. It is also a way to get information
out to other people. Many internet service providers give their customers a com-
plimentary address for a home page (excluding the cost to develop the home
page). For help with developing and maintaining a home page, contact your inter-
net service provider or a consultant — or your high school or college.
^ Home pages can be an effective way to get information out to the as-
sociation's membership or build interest in a project. The most effective
web pages are colorful with graphics, contain useful information that is fre-
quently updated, and have interesting links to related sites. Home pages
require maintenance, however. Usually, you can tell how useful a web site
is by the number of people who visit it and how often it's updated.
^ E-mail is one of the internet's most useful tools. It allows people to stay
in touch easily. For example, a lake association board could use it to main-
tain communication about important lake projects and issues. It is also
very cost effective. An e-mail usually costs less to send than a long dis-
tance phone call.
^ List servers ("list servs") are e-mail subscriptions (usually free) to on-
line sources of information usually contributed by and among subscribers.
For example, the Wisconsin Department of Natural Resources has a list
server on lake topics. Many list servers are managed by government, non-
profit, or universities as an inexpensive way to disseminate information to
many people about news or current issues related to specific topics.
Land-use Planning and
Stewardship
Many land uses contribute pollutants to lakes, including shoreline development,
agricultural activities, new construction, and stormwater runoff (see Chapters 2,
4, and 6). Protecting a lake from these activities requires an equally diverse ap-
proach, using tools such as local regulations, education, best management prac-
tices, and citizen action.
States and communities across the nation are realizing the impact of land-
use decisions on lakes. In Michigan, a special committee appointed by the Gover-
nor has identified inadequate land-use planning as the greatest threat to the envi-
ronment, including water quality. Communities in New York's Catskill Mountains
are implementing watershed management plans to protect the Delaware River
Reservoirs, the source of New York City's drinking water.
Many regulatory land management tools ranging from zoning to conserva-
tion easements can be used effectively in lake management:
Regulatory Approaches
Environmental protection is rooted in regulations. The Clean Water Act in 1972
set standards for industrial and wastewater treatment plant discharges. States
soon followed by passing their own regulations to reduce pollution to lakes and
rivers. Although federal and state regulations are important for protecting lakes,
342
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CHAPTER 9: Lake Protection and Maintenance
local regulations can build upon them by requiring stronger standards or different
components to accommodate unique local needs.
Zoning ordinances, special regulations, and innovative and creative land manage-
ment tools continue to be used by states and local communities to control activities
that can damage valuable water resources. These regulatory procedures can be com-
bined in any number of ways to fit a particular lake or specific set of lake uses.
Zoning Ordinances
Protecting or improving our lakes requires managing more than just the immedi-
ate shoreline area (see previous chapters on watershed management and pol-
luted runoff). More than 1.5 million acres of land are newly developed in the
United States each year (Center for Watershed Protection, I998a,b). These
changes in land use can greatly influence the long-term health of our lakes.
Originally developed to minimize conflicts between incompatible land uses
such as industrial and residential areas, zoning ordinances today do much more
than prevent conflict. They establish the pattern of development, protect the envi-
ronment and public health, and determine the character of communities. Since
protecting the lake requires looking at what happens on land, zoning is a natural
lake management tool.
Zoning's effectiveness depends on many factors, particularly the restrictions
in the language, the enforcement, and public support. Many people believe the law
protects sensitive areas, only to find otherwise when development is proposed.
Although zoning has its critics, it can be used very effectively for managing land
uses in a way that is compatible with lake management goals. Some zoning ap-
proaches that support lake and watershed management protection:
^ Site Plan IZev/ew standards require that the proposed construction
project meet additional requirements beyond the basic zoning ordinance.
A site plan consists of all the drawings, descriptions, and other information
pertaining to the proposed development, plus specifics on how the project
will affect adjacent properties and a pollution prevention plan. Site plan re-
view standards are often applied to commercial and industrial uses, land
uses requiring more than a specified number of parking spaces, structures
greater than a specified size, and development in sensitive environmental
areas — but not usually to single-family homes. Examples include require-
ments for:
• Keeping the property in as natural a state as possible;
• Controlling soil erosion;
• Stormwater management; and
• Street and access standards.
v Planned Unit Developments (PUDs) are commonly used in
zoning ordinances to trigger a site plan review, achieve stricter standards,
provide flexibility, and streamline the approval process for larger develop-
ments. Many include density bonuses in return for conservation lands set
aside for permanent protection.
lore than 1.5
million acres of land
are newly developed
in the United States
each year.
343
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Managing Lakes and Reservoirs
I F 6 E H
CIEG
RESIDENTIAL DISTRICTS BUSINESS DISTRICTS
..,,.. yii M liiilm III. Ill mi
[R-«] One family isc 43.ssaM.it. E;&S?| SCB Shopping center
tJJTjtji'j One family NT a,mn.n. HSU NB Neighlmrhooil business
so acres DEO One family iir is,!)«:,.n. ^H3 OB Office building
rivicr] One family is- n«!,.n. MM CB Central business
is- iMtoii. it-
One family is- 11,119 M. it.
30 acte$ FRM-'T| One and two family s»»»iiisj m SI.IIJH in
INDUSTRIAL DISTRICTS
WSI Wholesale and service
LI Light industry
HI Heavy industry
sew m Fur
210' !Mtts<.lt.uUStliS(.n.|ttfia.
A typical zoning map, this one from Smithtown Planning Board, N.Y., printed in the
Long Island Regional Planning Board's Nonpoint Source Management Handbook
(1984).
344
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CHAPTER 9: Lake Protection and Maintenance
' Overlay Zones: Although it appears to be very simple, this tool is ac-
tually very powerful. Overlay zones require stricter standards than
existing zoning because of special natural or cultural features. This type of
zoning is often used to require different regulations in sensitive areas such
as lake and stream corridors, where they can help reduce polluted runoff.
Such overlay zones often require building setbacks, greenbelt maintenance,
and limits on certain activities.
' Open Space Ordinances: Many municipalities are adopting open
space development and conservation design standards to protect natural
areas and create more livable neighborhoods. This type of ordinance gen-
erally requires that a certain percentage of the property be set aside as
open space to be used for recreation by all the property owners. Many or-
dinances also include a density bonus: the higher the percentage of open
space set aside, the greater the number of homes allowed. An easement
must be placed on the open space to keep it undeveloped forever.
Many communities are discovering that the lots in open space subdi-
visions sell more quickly and at a higher price than those in typical subdivi-
sions. These developments can help protect lakes by preserving valuable
wetlands and reducing the amount of impervious surface that generates
polluted runoff.
EXISTING COUNTY ROAD
UKEqUALITY
Traditional subdivision
design for a 10-aere site
zoned for half-acre sites
and bordered by a county
road on the north, a lake
on the south.
A conservation design that
respects the natural
resource base while
providing home sites in a
natural setting allots
approximately 5 acres of
the total 10 to common
conservation areas to be
used by all residents.
Source: Planning for
Success, Tip of the Mitt
Watershed Council (1999).
EXISTING COUNTY ROAD
Density bonus: The higher
the percentage of open
space set aside, the greater
the number of homes
allowed.
345
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Managing Lakes and Reservoirs
Model Development Principles
Developed by The Center for Watershed Protection, these principles go beyond reducing the
amount of impervious surface to suggesting how to manage areas for cars, buildings, and
conservation so as to reduce runoff. Many of these principles accomplish other goals,
including treating stormwater and protecting sensitive habitats.
RESIDENTIAL STREETS AND PARKING LOTS (Habitat for Cars)
1. Design residential streets for the minimum required width needed to support travel lanes,
on-street parking, maintenance, and emergency and service vehicle access. Travel volume
will determine the widths.
2. Reduce the total length of new residential streets by examining alternative street layouts to
determine the most efficient and appropriate placement of homes.
3. Wherever possible, residential street right-of-way widths should reflect the minimum
required to accommodate the travel-way, the sidewalk, and vegetated open channels for
stormwater. Utilities and storm drains should be located within the pavement of the
right-of-way wherever feasible.
4. Minimize the number of residential street cul-de-sacs and incorporate landscaped areas to
reduce the amount of pavement. The radius of cul-de-sacs should be the minimum required
to accommodate emergency and maintenance vehicles. Alternative turnarounds should be
considered, such as "T" designs that use less pavement.
5. Where density, topography, soils, and slopes permit, vegetated channels should be used in
the street right-of way to convey and treat stormwater runoff.
6. The required parking ratio (number of spaces required per business, etc.) governing a
particular land use or activity should be enforced as both a maximum and minimum to
curb excess parking space construction. Existing parking ratios should be reviewed for
conformance, taking into account local and national experience to see if lower ratios are
warranted and feasible.
7. Parking codes should be revised to lower parking requirements (number of parking spaces
a business must provide) where mass transit or enforceable shared parking arrangements
exist.
8. Reduce the overall amount of hard surfaces in parking lots by providing compact car
spaces, minimizing stall dimensions, and using pervious surfaces in extra, spillover
parking areas where possible.
9. Provide meaningful incentives to encourage structured and shared parking to make it more
economically viable.
10. Wherever possible, provide stormwater treatment for parking lot runoff using bioretention
areas, filter strips, and/or other practices that can be integrated into the landscape.
LOT DEVELOPMENT
11. Advocate open space design development incorporating smaller lot sizes to minimize total
impervious area, reduce total construction costs, conserve natural areas, provide
community recreational space, and promote watershed protection.
12. Relax side yard setbacks and allow narrower frontages to reduce total road length in the
community and overall site imperviousness. Relax setback requirements to minimize
driveway lengths to reduce overall lot imperviousness and require greater setbacks from
the lakeshore.
13. Promote more flexible design standards for residential subdivision sidewalks. Where
practical, consider locating sidewalks on only one side of the street and providing
common walkways linking pedestrian areas.
14. Reduce overall lot imperviousness by promoting alternative driveway surfaces and shared
driveways that connect two or more homes together.
346
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CHAPTER 9: Lake Protection and Maintenance
15. Clearly specify how community open space will be managed and designate a sustainable
legal entity, land trust, or government agency responsible for managing both natural and
recreational open space.
16. Direct rooftop runoff to pervious areas such as yards, open channels, or vegetated areas,
and avoid routing rooftop runoff to the roadway and the stormwater conveyance system.
CONSERVATION OF NATURAL AREAS
17. Create a variable width, naturally vegetated buffer system along all water bodies. This
buffer should also encompass critical environmental features such as the 100-year
floodplain, steep slopes, and wetlands.
1 8. Preserve or restore the riparian stream buffer with native vegetation. The buffer system
should be maintained through the plan review, construction, and post-development stages.
19. Clearing and grading of forests and native vegetation at a site should be limited to the
minimum amount needed to build, allow access, and provide fire protection. A fixed
portion of any community open space should be managed as protected green space,
preferably in a consolidated manner.
20. Conserve trees and other vegetation at each site by planting additional vegetation,
clustering tree areas, and promoting the use of native plants.
21. Provide incentives and flexibility in the form of density bonuses and property tax reduction
to encourage conservation of stream buffers, forests, meadows, and other areas of
environmental value. In addition, off-site mitigation consistent with locally adopted
watershed plans should be encouraged.
22. New stormwater outfalls should not discharge unmanaged stormwater into lakes or
streams, wetlands, sole source aquifers, or other sensitive resources.
Special Ordinances
States and communities can also adopt regulations designed to manage a specific
activity or resource. Adopting, implementing, and enforcing state and local regula-
tions require a commitment to the costs and time to administer them. Some of
these ordinances that have the most potential benefit for lake management:
V Soil Erosion and Sformwafer: Soil erosion and stormwater are
two leading water pollutants in the United States. Local ordinances can re-
duce the impacts of erosion and stormwater, especially from new
construction. Soil erosion ordinances often require detailed plans that
show how erosion will be prevented for any earth disturbance that is near
surface water or is of a certain size (e.g., one acre) — plus provisions to
ensure the plan is implemented appropriately. Stormwater regulations may
require preserving drainage patterns, keeping stormwater onsite, and
storing stormwater in retention and detention basins (or otherwise treat-
ing it) before it leaves a property.
^ Impervious Surface: New development replaces forests, meadows,
and wetlands with rooftops, roads, driveways, parking lots, and other hard
(impervious) surfaces that rain can't penetrate. As the amount of impervi-
ous surface increases so does the runoff to a lake and its tributaries.
Studies have shown that fish habitat is harmed when impervious surfaces
account for more than 10 percent of a watershed (Center for Watershed
347
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Managing Lakes and Reservoirs
*ne of the most
valuable tilings a
lliih" ];! Jlllliilliilli;'-•»!"«•' "J j "'
community can do for
tlakcs is to reduce the
amount of impervious
surface and identify and
protect critical habitats.
Protection, I998a,b). One of the most valuable things a community can
do for lakes is to reduce the amount of impervious surface and identify
and protect critical habitats (see the preceding Model Development Prin-
ciples).
Sanitary Ordinances
Most lakeshore areas in this country rely on on-site septic systems for wastewa-
ter treatment. Most communities have standards and regulations that determine
proper siting and design of septic systems, primarily to protect public health from
diseases that can be spread by wastewater. Some also focus on protecting the en-
vironment. These standards may include:
• Setbacks from water bodies and wells;
• Minimum allowable depth to groundwater;
• Soil suitability criteria; and
» Size requirements based on estimated usage by current and future
owners.
Some communities also have a septic system evaluation program to encour-
age the upgrade of older septic systems. When a home is sold, the septic system
must be evaluated to ensure that it meets current code requirements. If it doesn't
then the system must be upgraded. This type of program can be very valuable in
eliminating failing septic systems around lakes.
The criteria for evaluating septic systems must be developed carefully. The
National Small Flows Clearinghouse is a valuable source of information on design,
construction, and management of septic systems. Operated by the University of
West Virginia for the U.S. EPA, the Clearinghouse helps small communities find
practical, affordable solutions to their wastewater problems.
Wetland Regulations
Preserving wetlands along the shoreline and in the watershed can help protect
the quality of lake water. Wetlands filter runoff, provide wildlife habitat, prevent
shoreline erosion, and help control flooding. Federal laws protect wetlands' valu-
able functions by regulating activities that degrade or destroy wetlands. Some
state and local governments have also adopted additional regulations to protect
wetlands.
Although local wetland ordinances add another layer of regulation for citi-
zens, they can benefit property owners and communities in many ways. Often, lo-
cal ordinances will require a community-wide wetland inventory that will identify
wetlands that require permits, thus saving time and money in the long run.
Almost more important, local involvement can help streamline the wetland
permit process, which at best, is difficult.
Key elements of a local ordinance may require:
• Additional setbacks for construction, and
• Protection of smaller wetlands that may not be regulated by other
state or federal laws.
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CHAPTER 9: Lake Protection and Maintenance
Lakeshore wetlands protect the health of the entire lake ecosystem in many •ways,
including nurturing aquatic life and preventing pollutants from reaching the lake.
Photo by Jim Nelson.
Growth Management Tools
When combined with a sound zoning ordinance and a clear master plan for the
community, growth management tools can improve the way land is used in the
community and thus protect the lake and its watershed. These tools will not stop
growth; they just guide the rate, location, type, timing, quality, and character of de-
velopment to comply with the regulations and master plan.
But growth management tools can only influence new growth and develop-
ment. A community that has almost reached its limits with urban sprawl will
benefit less from growth management tools than areas that are just beginning to
experience a population surge.
The following growth management tools, which can be used individually as
well, can be a valuable part of a lake and watershed protection effort:
• Purchase and transfer of development rights;
• Urban growth boundaries; and
• Coordinated infrastructure management.
Purchase and Transfer of Development Rights
Every piece of property comes with a certain amount of "rights" such as the right
to harvest timber, build structures, farm, etc. Purchase-of-development-rights pro-
grams actually buy the "right" to develop the property from the property owner
in perpetuity.
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Managing Lakes and Reservoirs
A program that supports the purchase of development rights gives farmers
an alternative to subdividing their land and selling it to gain retirement income,
which results in loss of both agricultural acreage and open space. They can sell
the development rights to provide for their retirement without having to sell
their land; they can also continue to farm it, harvest timber, etc. Selling develop-
ment rights does not yield as much profit as selling the land outright, but it main-
tains the rural character of a community.
Transfer of development rights is very similar, although it allows the develop-
ment density to be transferred to a property that is more suitable for develop-
ment.
Funding these programs is expensive. Some states purchase agricultural lands
and some communities are beginning to pass mill levies to support such programs.
Purchase and transfer of development rights can be used as lake manage-
ment tools to preserve important areas around a lake from pollution resulting
from development, but they work best when combined with other management
techniques. Since agriculture, for example, can also pollute lakes, these programs
should be combined with installing best management practices on farms.
Urban Growth Boundaries
Boundaries are carefully drawn around a city or village to prohibit urban develop-
ment beyond the line. As a result, development and economic growth are focused
on an area in a way that avoids urban sprawl. Service district boundaries are
similar, using public services such as sewer and water to concentrate develop-
ment within a certain area. Another way to concentrate urban development near
infrastructure is the village center concept, which uses mixed zoning to pro-
vide a variety of land uses such as residential, commercial, and industrial within a
small area. The village center concept builds a community where a person could
conceivably live, work, shop, visit doctors, etc., all within walking distance.
The State of Oregon required its communities to adopt urban growth
boundaries by the mid-1980s. Drawing the lines was very controversial. However,
after more than a decade of having urban growth boundaries in place, positive re-
sults can be measured. A 1991 study of the Portland metropolitan area found that
it had expanded only 2 percent in area over the last 17 years, while significantly
growing in population and development. Those statistics cannot be matched by
any other urban area in the United States.
Urban growth boundaries can be a very beneficial land management tool for
lakes near urban areas. They can help concentrate infrastructure and new devel-
opment where it is best suited.
Coordinated Infrastructure Management
The decision to approve a new shopping center or large resort development usu-
ally rests with the municipality where the property is located. Even though a proj-
ect may also affect a neighboring township and its lake through increased traffic,
road damage, and stormwater runoff (among other things), its approval is seldom
required. In addition, the neighboring township will not likely receive any financial
benefits in taxes from the development.
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CHAPTER 9: Lake Protection and Maintenance
Since lake and watershed boundaries generally do not coincide with political
boundaries, the effects of development on lakes in neighboring jurisdictions usu-
ally are not considered. One way to address this issue is for the municipalities to
adopt impact coordination rules. These require local governments to con-
sider the impacts of projects on neighboring communities by soliciting comments
from that municipality. Impact coordination rules can vary greatly, from having to
notify a neighboring community about a project to mandating their approval.
Carrying Capacity Studies
As our population has grown — and more people have had more money to
spend — they have increasingly turned to lakes for recreation and relaxation.
Lakes are straining to keep up with the demands for boating facilities and homes
along their shorelines. Boaters now have to schedule their time on the water, and
homes are being wedged in using keyhole (funnel) designs.
Motorboats, including personal watercraft, affect the lake in several ways, in-
cluding contributing to pollution. Lake users also conflict, which is to be expected
when you have sailboats, anglers, speedboats, water skiers, swimmers, personal
watercraft, canoeists, windsurfers (and more!) sharing the same waters. Some of
the more common issues:
• Shoreline erosion from speedboats and water skiing (and loss of
natural habitat as shorelines are artificially altered to prevent erosion).
• Damage to bottom-dwelling plants and animals near the shore (littoral
zone).
• Oil and gas discharge from powerboats.
• Noise.
Good boating practices protect the health of this lake.
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Managing Lakes and Reservoirs
.
property management
practices can go a long
way toward maintaining
land protecting lake
water qualify — from
how you care for your
lawn to how you
operate your boat.
A carrying capacity study for recreational boating can determine the number
of boats that can be used safely in a lake. Generally, these studies assess lake char-
acteristics and levels of boating activity by residents and the public, and help clar-
ify the conflicts. Some studies also assess potential damage to water quality from
boating (Engel, 1989).
Carrying capacity studies often produce lake-specific regulations that dictate
when and where motorboats can operate and designate zones in the lake that are
appropriate for specific uses. For example, pleasure motor boating and water ski-
ing might be banned between 6 p.m. and 10 a.m., to minimize conflicts with an-
glers. Another approach is to set aside certain areas, such as sheltered coves of
the lake, for particular uses such as swimming or fishing, with power boating and
water skiing restricted to more open water areas (Wyckoff, 1995).
Although most states require minimum isolation distance between water-
craft and restrict watercraft speed, stricter regulations could be specified: for ex-
ample, a powerboat should be at least 200 feet away from an anchored fishing
boat or restricted to slow no-wake speed. Motor sizes are commonly restricted
(no motors, only electric motors, or only motors less than 10 hp) on small lakes
or lakes in wilderness settings. State environmental agencies often cooperate with
local governments to establish stricter boating regulations.
A carrying capacity study can also provide data to limit the number of boats
lakefront property owners can maintain. Or limit boat usage by restricting the
number of boats per lake residence and controlling the amount of parking at pub-
lic access sites. These would require ordinances and may be easier to establish on
a lake that is just being developed.
Boating and recreational use issues can be emotional. If you decide to con-
duct a carrying capacity study, be sure it takes a scientific approach to assessing
impacts. And remember, establishing special regulations for a lake may require
working cooperatively with the state environmental department and state and lo-
cal marine patrol.
Voluntary Activities
Regulations alone cannot protect a lake; riparian property owners significantly af-
fect water quality and must do their part. Although encouraging them to change
their behavior and voluntarily help protect a lake may seem like a daunting task,
lake communities all over the country have validated Margaret Mead's words:
"Never doubt that a small group of thoughtful, committed citizens can change the
world. Indeed, it's the only thing that ever has."
Personal Property Management Practices
The privilege of lakefront living comes with an enormous responsibility, because
anything you do along the lakefront can have an immediate effect on a lake's eco-
system. Good shoreline property management practices can go a long way to-
ward maintaining and protecting lake water quality — from how you care for
your lawn to how you operate your boat. Use the following checklist as a guide,
and supplement it with the publications and programs cited in the references and
text throughout this book.
^ lawn Care: To many people a yard without a lawn is not a yard. But a
large, intensively managed lawn along a lake shore may not be the best
thing for the lake. In fact, studies have indicated that lawn fertilization is
one of the largest sources of pollution.
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CHAPTER 9: Lake Protection and Maintenance
Lawn Care Tips:
• Maintain a strip of natural vegetation along the shoreline, or plant one,
preferably with native species.
• Leave an unmowed, unfertilized area at least 25 feet wide along the
water's edge.
• Locate your compost pile away from the shoreline.
• Test the soil to determine the most appropriate fertilizer needed.
• Use a low maintenance, slow growing grass seed that is recommended
for your soil conditions and climate.
• Keep the grass as high as possible (3 or more inches) to shade out
weeds and improve rooting so less water is required.
• Use a self-mulching lawn mower, which will reduce or eliminate the
need for fertilizer.
• Avoid using fertilizer. If fertilizer is absolutely necessary, use a slow
release product low in nitrogen and phosphorus free.
• After raking leaves, add them to the compost pile. Avoid dumping
leaves on or near the shoreline — they can attract leeches.
• Avoid or minimize the use of pesticides whenever possible.
• Landscape with native species that are suited for the specific site: its
soil, light, and moisture conditions.
• Consider a lawn of pine needles or native ground covers instead of
turf grass.
• Do not try to grow grass on a wooded lot.
A lakeshore greenbelt such as this one along Lake Lawrence, Wis., filters potential
pollutants as well as being aesthetically pleasing. Photo by Wisconsin Department of
Natural Resources.
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Managing Lakes and Reservoirs
Septic Systems: When designed, constructed, and maintained prop-
erly, septic systems can provide excellent wastewater treatment for homes
in rural areas. But when they have problems, they can leach nutrients and
bacteria to the lake. Proper maintenance can prevent many problems and
help ensure that the system operates effectively throughout its expected
lifetime.
Septic System /Maintenance Tips:
• Have the septic tank sludge level inspected and pumped out as needed
based on occupancy (commonly every three to five years depending
on seasonal or permanent use).
• Consider adding a septic effluent filter to help keep solids out of the
drainfield. However, a filter requires that the septic tank be pumped
more frequently.
• Conserve water by installing water conservation devices.
• Reduce water use by turning off the faucet while brushing teeth and
washing only full loads of laundry.
• Carefully use household hazardous materials such as drain cleaner,
paints, varnish, and motor oil.
• Dispose of leftover household chemicals at a household hazardous
waste collection site. Do not dump down drain.
• Recycle used motor oil and antifreeze.
• Never build, pave, or cultivate land over a drainfield; don't drive
vehicles over a drainfield.
• Don't apply fertilizer around a drainfield because the nutrients saturate
the soil and cause it to stop removing nutrients from the wastewater.
effluent sewer
soil absorption field
house sewer
water level
\ \ \
septic tank
A schematic of a typical septic system. From Tip of the Mitt Watershed Council.
V Shoreline Erosion: Waves, currents, and ice move soil particles to-
ward, away from, and along the shoreline. People augment this natural
erosion by removing vegetation, dredging, filling, or building along the
shoreline. As discussed earlier in this manual, the resulting sediment can
destroy habitat and affect fish and other aquatic organisms, cloud the wa-
ter, and stimulate (because it may contain nutrients) undesirable plant and
algal growth. Shoreline erosion can also destroy valuable waterfront prop-
erty, including buildings. You may need to install either structural or
biotechnical (vegetative) erosion controls.
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CHAPTER 9: Lake Protection and Maintenance
Shoreline Erosion Prevention Tips:
• Preserve the natural rocks and vegetation along the shoreline.
• Prevent runoff from roofs and driveways from flowing over land to the
shoreline by directing it into a swale or collection area or away from
the lake.
• Maintain nearshore "berms" pushed up by ice action in northern
areas.
• Preserve shoreline wetlands.
• During construction, implement proper soil erosion control measures
to prevent sediment from washing into waterways.
• Avoid using seawalls, because they can cause erosion on neighboring
properties and destroy valuable habitat for aquatic life.
• Limit the amount of foot traffic and other recreational activities in
erosion-prone areas.
' Powerboating: Motor boating and personal watercraft are some of
the most popular recreational activities on lakes. They can be fun and ex-
citing ways to experience lakes — but they can also negatively affect them.
Proper maintenance and responsible use of power boats can greatly re-
duce their impact.
Watercraft Pollution Prevention Tips:
• Maintain the boat motor, since well-tuned motors contribute the least
amount of pollution.
• Refuel on land to reduce any chance of spilling oil or gas into the
water.
• Check and clean the engine well away from shorelines. Oil can harm
micro-organisms and other aquatic life that feed on them.
• Be careful when filling the tank; do not overfill. Catch accidental spills
with an absorbent pad and dispose of it properly.
• Obey no-wake zones and avoid shallow areas to prevent disturbing
vegetation, wildlife, and bottom sediments.
• When it is necessary to ride in shallow water, keep watercraft at idle
(headway) speed. This will help reduce the stirring-up of bottom
sediments.
• Avoid vegetated areas, including docking around reeds and grasses.
The boat motor may suck them in, causing engine or pump problems.
But the plants themselves may be pulled out or damaged by stirred-up
sediments or less light.
• Avoid marshy areas and aquatic plant beds. They are important habitat
for fish, birds, turtles, snake, frogs, and other aquatic life.
• Protect wildlife by maintaining a buffer of 300 feet or more between
the boat and animal. Learn about protected species found in lakes and
what you should do to avoid disturbing them.
Let Fallen Trees Lie:
Resist the urge to
immediately clean up a
fallen tree: such trees — and
overhanging plants — are
mini-food chains. Small fish
gather beneath them to feed
on insects and use their
cover to hide from larger
predator fish.
Researchers from Ontario
have found that shoreline
sites with more fallen trees
produce more preyfish than
shorelines where these trees
have been removed. They
also found that along
undeveloped shorelines, fish
feed at levels seven times
higher.
Shorelines Equal
Habitat: Using the green
frog (Rana clamitans) to
check the health of aquatic
life in northern Wisconsin
lakes, researchers have
found that as the number of
homes increases, the number
of green frogs declines.
Undeveloped lakes averaged
one frog per 126 feet of
lakeshore compared to one
frog per every 220 feet for
developed lakes and 470
feet on densely developed
lakes. Protecting a certain
amount of shoreline from
development may help
protect aquatic life, including
the green frog.
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Managing Lakes and Reservoirs
Prevent the introduction
of exotic species (e.g.,
zebra mussels, round goby,
Eurasian watermilfoil, etc.),
by draining the bilge motor,
live well, and transom while
on land; inspecting the boat,
trailer, and anchors;
removing any visible plants
or animals before leaving
the lake; and emptying bait
buckets on land.
Miscellaneous Shoreline Management Tips:
• Place campfire rings as far back from the lake as possible. When fires
are cool, collect ashes and add to compost pile or dispose properly.
• Maintain aquatic vegetation in the shallow areas of the shoreline.
These provide valuable wildlife habitat and protect the shoreline from
erosion.
• Don't feed the waterfowl. This will increase the amount of waterfowl
feces that contribute nutrients to your lake; waterfowl also help
spread swimmer's itch.
• Pick up pet waste and dispose of it properly to prevent it from making
its way to a waterway in a rainstorm.
• Use an indoor shower rather than the lake for bathing.
• Divert rain gutters to unpaved areas where water can soak into the
ground before reaching the lake.
• Participate in your lake association. For example, the lake association
could develop a "welcome wagon" service that gives new owners a
packet of information on lakeshore living and gifts and coupons from
area businesses. Brochures, newsletters, press releases, and other
media tools are other excellent ways to reach property owners.
Land Protection Through Purchase,
Donation, or Easement
Permanently protecting ecologically valuable land in the watershed is another lake
and watershed management tool that preserves sensitive habitats that are critical
for lake protection; it also can be combined with other lake management efforts.
First, you must inventory sensitive areas around the lake and in the water-
shed. The inventory might identify and characterize sensitive areas such as wet-
lands, steep slopes, wildlife habitat, ecological corridors, threatened and
endangered species, etc.
Next, prioritize the sensitive areas and identify the property owners. Then,
you will want to work with the private landowners to discuss land management
and protection options that would protect the property from uses that might harm
water quality. Land protection must be voluntary, ranging from placing future re-
strictions on use of the property to selling the land.
Protecting sensitive areas from development can help reduce runoff and pol-
lution entering lakes. Purchasing lands for conservation value can also be an effec-
tive, though expensive, watershed management tool. Many citizens are interested
in preserving the conservation values of their land for their grandchildren and fu-
ture generations.
V Conservation easements (also known as conservation restrictions)
are legal agreements between a landowner and a qualified government
agency or nongovernmental organization (most commonly a land trust) that
permanently limit a property's uses; they remain with it if it is sold. A con-
servation easement does not transfer title to the property or open it to
the public. The landowner continues to own the property, and may live on
it, sell it, or pass it on to heirs. The donation of a conservation easement
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CHAPTER 9: Lake Protection and Maintenance
can lower estate taxes and provide income tax or property tax deduc-
tions. Conservation easements are extremely flexible and can be written
to meet specific needs of the landowner.
Outfight donation of land to a land trust or government agency
is another way to protect sensitive habitats. This option has several bene-
fits for the landowner:
• It is a simple transaction;
• It can provide significant income tax deductions; and
• It can reduce estate taxes.
Land trusts, one of the fastest growing sectors in the conservation
arena, specialize in land protection. They manage property that has been
donated to them, and hold and enforce conservation easements on lands
they purchase. Generally, land trusts will only accept or purchase lands
that have conservation value.
Lake Monitoring
Monitoring programs have been covered in previ-
ous chapters, but they are discussed here again to
emphasize their importance and to introduce the
role of volunteers. Water quality monitoring is im-
portant for characterizing these dynamic systems
we know as lakes, understanding how they work,
and documenting changes and trends.
One of the most popular reasons for moni-
toring water quality is to detect or document
problems. It is easier and much more cost effective
to treat lake problems as they develop rather than
when they have become a crisis. Water quality
monitoring is also the best approach for determin-
ing whether protection and restoration ap-
proaches are effective.
But who should do the monitoring — pro-
fessionals or volunteers? The answer is both. Pro-
fessional monitoring is an essential part of a lake
management plan. And volunteer monitoring can
provide supplemental information that will
strengthen a professional monitoring program.
Volunteer monitoring also strengthens your
entire program because as more people become
involved in monitoring, they learn more about the
lake, its problems and opportunities, and ongoing
efforts to protect it. (An excellent reference on
volunteer lake monitoring is Volunteer Lake Moni-
toring: A Methods Manual [Simpson, 1991 ]).
Volunteers prepare to monitor for newly hatched zebra mussel
larvae on Black Lake, Mich.
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Managing Lakes and Reservoirs
Volunteer monitoring used to be limited to measuring Secchi disk transpar-
ency and the occasional chlorophyll a test to check algae. Not anymore. The op-
portunities for volunteer monitoring are almost limitless. As government budgets
diminish, the need and demand for volunteer monitoring programs will continue
to increase. Expanded chemistry parameters, such as dissolved oxygen, pH (alka-
linity), and conductivity, are becoming more popular, as are programs to check for
the presence and abundance of certain exotic species such as zebra mussels or
Eurasian watermilfoil.
Check with state agencies to learn about their volunteer monitoring pro-
grams. If state programs are not available, contact local universities, conservation
districts, and other local resources for assistance with developing a volunteer
monitoring program.
Establishing a Volunteer
Monitoring Program
1. Setting Objectives
The first step in developing a volunteer lake monitoring program is to establish
objectives. Is the objective to provide credible information on water quality con-
ditions to state and local agencies? To educate the public about water quality is-
sues? Or to build a constituency of involved citizens? All of these objectives (plus
many others) can be achieved by a well-organized and carefully implemented pro-
gram, but you must first determine your priorities.
2. Working with Potential Data Users
Potential users of the data besides your lake organization may include state envi-
ronmental department employees such as water quality specialists, biologists, and
fisheries managers; local planners and environmental organizations; agricultural
agencies; universities; and certain federal agencies.
Before you set up your program, communicate with these potential data us-
ers about your program goals, what data they might need, and what methods of
data collection, analysis, management, and reporting they recommend or would
accept. Federal and state governments may not consider the data valid if certain
methods weren't used to collect it.
^ Data Management* This step is often forgotten until after a few
years of data have accumulated. But the best time to determine data man-
agement is before any data have been collected. What is data management?
Data management involves storing data in a manner that makes information
easily accessible and accurately retained: a good data management system
might store the data in a computer data base or well-organized file folders.
When determining how to store and manage your data it is helpful to
consider how you plan to use the information. Computer databases (such
as Lotus, Excel, FoxPro) offer many advantages, including efficient storage,
data-sharing opportunities, and the ability to print graphs. When choosing
any data management system consider who will enter the data, maintain
the database, and distribute the data. Although a computer database may
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CHAPTER 9: Lake Protection and Maintenance
seem the most efficient process, if there is no one to enter the data then
a simpler management system may be better.
Human error may show up more in the data management portion of a
volunteer monitoring program than in the actual monitoring. It is important
that if data are entered into a computer or other filing system that it be
checked to insure that the data stored are complete, calculations are correct,
proper units are reported, and the results are reasonable (Lease, 1995).
' Reporting and Using the Data. Using the data may seem like
the easiest part of the water quality monitoring program, but it can be an
overwhelming task and is often left behind in the hustle. Data should be
used on a regular basis (quarterly or annually) or volunteers may question
the relevance of their efforts. Of course the data should be used in a man-
ner that is consistent with the original goal of the program. Data use can
involve everything from volunteers presenting findings at fairs or commu-
nity meetings to state agency use of the data in its biennial water quality
report to EPA.
When presenting data remember that it shouldn't be too technical or
too simple for the intended audience. Graphics, including charts and draw-
ings, can help dramatically. If you use charts or tables, accompany them
with descriptive text, written in plain English (not water quality monitor-
ing jargon) if the audience is not familiar with such terminology. Describe
the program's purpose to give it meaning.
Data should be presented with a purpose: to show trends, seasonal
variations, or indicate problems that relate to the purpose of the monitor-
ing program. For example, a graph might be used to show trophic status in-
dex values from year to year, dissolved oxygen/temperature profile for
different months, or bacteria counts at public beaches in different locations.
Data presentations should also be timely and relevant to the lake
condition. For example, sending out a press release in January reporting
on high bacteria levels detected at beaches in August would be too late.
However, sending out an annual summary of the data that included the
high bacteria levels in August and emphasized the need to find solutions
prior to the next summer would be effective.
3. Selecting Parameters and Methods
Determining the proper parameters and sampling methods to meet the goals of
the program can be tricky. Professional lake managers can help you with this.
The objectives of the monitoring program determine the lake conditions and
parameters to be monitored. For example:
• If lake residents are concerned about water quality affecting a lake's
coldwater fishery, then you need to monitor dissolved oxygen and
temperature; or,
• If the beaches have been closed because of bacteria, then a special
study measuring bacteria levels along the shore and inlets (or
tributaries) would be helpful.
• If very little water quality data have been collected on your lake, then
you need to do baseline monitoring that would include many chemical
and biological parameters.
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Managing Lakes and Reservoirs
When selecting the parameters and methods consider how the data will be
used. That requires understanding the meaning of the test results, e.g., know the
background levels for the parameters monitored, how weather may influence the
data, water quality protection criteria, seasonal trends, data ranges, etc.
A carefully planned monitoring program can provide useful information to
accomplish its objective. But interpret data cautiously. It cannot always prove
what you would like it to. A set of data collected at one time provides a snapshot
of the lake's condition at that one time. You may want to contact local profession-
als to help interpret the data you've collected. For more information, visit EPA's
volunteer monitoring web site at www.epa.gov/owow/monitoring/vol.html.
4. Quality Assurance/Qualify Control
Given proper training and supervision, volunteers can conduct monitoring and
collect samples that yield high quality data. To ensure its quality will be acceptable
to other agencies, you should adopt quality assurance/quality control (QA/QC)
measures.
Quality assurance/quality control are often used interchangeably but they
have different meanings. Quality assurance reviews all aspects of the monitor-
ing — planning, implementation, and completion — to ensure high quality data
are collected. Quality control is performed during data collection to ensure ac-
curacy, precision, and unbiased monitoring.
Five major areas must be addressed when developing a quality assur-
ance/quality control program:
• Accuracy,
« Precision,
* Representativeness,
• Completeness, and
e Comparability.
See Quality Assurance/Quality Control box for descriptions of these areas.
A quality assurance/quality control program will reduce potential problems with
data collection and can improve the experience for volunteers.
For more information on developing a Quality Assurance Project Plan
(QAPP) — essentially a document that outlines procedures to ensure that data
meet project requirements — see EPA's document, A Volunteer Monitor's Guide to
Quality Assurance Project Plans (EPA 841-B-96-003) at www.epa.gov.owow/moni-
toring/volunteer/qappcovr.htm. You can also order this document by calling (800)
490-9198.
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Quality Assurance/Quality Control
Accuracy: The degree of agreement between the sampling result and the true value of the
parameter being measured. Accuracy is most affected by the equipment and the
measurement procedure: calibrate equipment carefully according to equipment or standard
method requirements and test against a known standard. If conducting pH monitoring with
an electronic probe, use standard solutions of known pH values to examine and calibrate
its accuracy.
Precision: The ability of the monitor to reproduce the data result on the same sample
(regardless of accuracy). Human error in sampling techniques plays an important role in
estimating precision. For example, a replicate sample, which entails collecting two or more
samples at the same site, same time, using the same methods, and analyzed with the same
technique can be used to check a monitor's precision.
Representativeness: The degree to which the collected data accurately and precisely
represents the lake condition being measured. It is most affected by sample site location.
For example, if the monitoring objective is to characterize the algal condition in a lake,
then the sample would be collected in the deepest, open water area of the lake, rather than
taking a sample along the shore near a stream mouth.
Completeness: A measure of the amount of valid data obtained versus the amount
expected to be obtained as specified in the original sampling design objectives.
Completeness is usually expressed as a percentage based on the number of sampling
dates expected and the number of actual samples taken. For example, if 25 sampling dates
were planned and only 20 samples were selected, due to bad weather and equipment
failures, the completeness would be 80%.
Comparability: This is often very important for citizen monitoring programs because it
represents how well data from one lake compare to data from another. For example, state
and regional agencies and local monitors should work together to establish standard
sampling methods and procedures for volunteer monitoring programs.
Source: Simpson, 1991.
5. Training Volunteers
Volunteers must be trained to perform water quality monitoring tests and follow
QA/QC procedures. Training will require time, materials, and probably profes-
sional assistance — items that can add costs to a monitoring program. But train-
ing is another monitoring investment that has high returns for a program.
First, develop a volunteer monitor description that details the duties
and tasks of the monitor. Use this to inform interested volunteers of their re-
sponsibilities.
Second, organize and hold the training. Training can be done in a group
setting or one-on-one. Both have their benefits.
• Group training builds camaraderie among the monitors. It is more
efficient, requiring less time than one-on-one training. It encourages
group problem-solving and ensures each volunteer receives consistent
information.
• One-on-one training can be more detailed and intensive and often
provides better results.
Combining the methods can be most effective but will require a greater in-
vestment in time and money. Bringing in professionals to help with group training
can be advantageous, especially if they will be using the data collected for a project.
Comparability: This is
often very important for
citizen monitoring programs
because it represents how
well data from one lake
compare to data from
another. For example, state
and regional agencies and
local monitors should work
together to establish standard
sampling methods and
procedures for volunteer
monitoring programs.
361
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Managing Lakes and Reservoirs
A thorough training session would include:
• A review of the monitor's responsibilities;
• Presentation on the relevance and value of each parameter;
• Review of quality assurance/quality control procedures;
• How to do the sampling and use equipment;
• How to record the data;
• Hands-on opportunities to collect samples and encouragement to
participate;
• Discussion of safety issues;
• Written instructions to take home, review, and use in the field; and
• Refreshments and time for socializing.
Allow ample time for questions and answers. And be sure to give volunteers
information on who to contact if they have problems or need additional assis-
tance. Give the volunteers an evaluation form; this will help trainers plan future
sessions.
Training is an ongoing part of volunteer monitoring programs. Annual train-
ing sessions bring in new monitors and provide refreshers for veterans.
A training session takes volunteer monitors out on a boat into their lake.
362
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CHAPTER 9: Lake Protection and Maintenance
6. Evaluating the Program
Taking the time to assess whether a program met its objectives is an important
component of all programs. An evaluation can look at many different levels of a
project or simply at the effectiveness of the overall program. And it can be done
by the volunteers or lake residents.
As with other components of the monitoring program, designing the evalua-
tion will take some effort. Not surprisingly, the most common ways of conducting
evaluations are written evaluations and interviews.
Some simple and effective evaluation questions might include:
• Did the program accomplish its goals;
• What worked well;
• What didn't work well;
• Did the project budget cover all expenses;
• Were the proper parameters monitored;
• Did the data help facilitate the desired change and/or meet the
program's objectives;
• Were the data distributed to the appropriate agencies;
• Did the data meet quality assurance standards; and
• What could be done to improve the program?
More specific questions that address the monitoring program's goals should
also be included.
Putting It All Together
Integrating protection and maintenance into a project may seem like an over-
whelming task, but taken one step at a time it is doable. Once you've identified
the project's goals and objectives, selected the most appropriate actions, and be-
gun work, then the most important task becomes assessing progress throughout
the lake management process.
Just as lake management activities are ongoing, so is the evaluation. An edu-
cation program on lakes might require assessing the students' and teachers' com-
ments about the program, and checking on the reactions of the volunteers or
staff who conduct the program as well. Lake monitoring is another way to evalu-
ate the effectiveness of management strategies. But remember, focus on the posi-
tive results and opportunities the evaluation finds, not the success or failure of
the program.
Maintenance and protection of lakes is ongoing, not short term. As time
passes and goals, objectives, and actions are accomplished, new opportunities to
improve and protect lakes will continually arise.
363
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Managing Lakes and Reservoirs
aspect for the
' Jri e and sound
iiiiiiiiiiiiiiii^^ ii . B •
ms are the basis
strong lake
foctation.
A Lake Association Profile
Every lake has a unique character. For Walloon Lake in Northern Michigan it may
be the call of the loons that nest in its quiet coves, the blue, clear color of the water,
f* or the lore of it being Ernest Hemingway's childhood vacation spot.
The Walloon Lake Association and its sister organization the Walloon Lake Trust and
Conservancy have worked to maintain its unique character since 1910 — and since
1960, have been extremely proactive in creating a variety of programs to preserve
", and improve the environment of Walloon Lake.
f The Walloon Lake Association:
I 'nalllilllllln» 1IIIII1IIIW gllllPlliKiillJHMIIiUillnlilllhiLW'ifWIiiMI u lliLailllMIW niruiillln'l' .JIM, ^lldlHtt, M HI,,,U,' ., ...l» « >•« „„•„ „ i ,^u ,
• Publishes six newsletters and a membership directory annually;
BlfWIPli'lll'IMif i HI! I'l'IISlHillirilllll!™" lllllllin.llllUH I'lBllill'MBIifni" iMIUM'1*!*^'«*-J-i,lf irM.Ml'rai'l'jj '» u M H.iw .. H. h,,.,,,, .,,,, H . d , , , .
• Disseminates information to lake residents through its neighborhood
," leadership committee"; and
• Sponsors numerous field trips and programs to encourage members and
their children and grandchildren to learn more about the lake and its
watershed.
F The Association's political sense is also on target: they appoint representatives to
£ attend, Ifjcgl government meetings of the five townships surrounding the lake — in
fact, several representatives have become official members of township boards and
t> planning commissions. As a result, local regulations such as building setbacks have
J been passed to help protect the lake.
Their water quality monitoring program includes:
• The usual Secchi disk^ chlorophyll a, and spring phosphorus;
• An expanded program that monitors dissolved oxygen, temperature,
conductivity, pH, and turbidity using a multi-parameter water quality testing
probe;
• An annual boat survey to keep tabs on the number of lake resident-owned
boats; and
MlllhiWHIhlnHI l4*«ai«ll«iifciniiWHtti***rHmlwlM*M NW.nlMWaihluwlKSUHi'MW.WJuu'Lumtt*),™ a,** -,i v,,,- rl,,, .,- . i,,, ,.,. ,
^',*i Special studies on shoreline algal communities, exotic species, and beavers
on tributaries.
| Their sister organization, the Walloon Lake Trust and Conservancy, has put
watershed protection into action by protecting 1,100-plus acres through gifts of land,
conservation easements, and purchases (with help from a regional land
conservancy).
The secret to their success? More than 90% of the lake residents belong to the
Association — which maintains a full-time executive director and an office in a
nearby town.
Walloon Lake Association's strength is built on the respect and care its members have
J for the lake. But it is the education, water quality monitoring, governmental affairs,
« land protection, and membership programs that will encourage future generations to
| Ipyejhelake and dp,g|| that's necessary to protect it.
,' " Respect for the resource and sound programs are the basis of a strong lake
I association.
i , ;..• ,...:; .., •.. ; . . ... ..
I
364
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CHAPTER 9: Lake Protection and Maintenance
Lake Maintenance and Protection:
An Ongoing Opportunity
"We did not inherit the earth from our ancestors, but are borrowing it from our
children." This quote attributed to Chief Seattle is particularly relevant for lake
management. Lakes are an important part of the American landscape and our cul-
tural and natural history. Restoring, protecting, and maintaining these resources is
an ongoing process that requires vigilance and dedication of lake property own-
ers, lake users, and governments.
But, oh, the rewards. Through sound lake management, future generations
will be able to hear the cry of a loon, see the reflection of a full moon, experience
the thrill of fishing, or feel the refreshment from a summer swim in lakes across
North America.
Henry David Thoreau wrote in Walden, "a lake is a landscape's most beauti-
ful, expressive feature; it is Earth's eye, on looking into which the beholder meas-
ures the depth of his own nature." May this powerful spiritual connection that
humans have with lakes be expressed with commitment and personal responsibil-
ity to protect and enhance these national water treasures.
References
Arendt. R. 1996. Conservation Design for Subdivisions. Island Press, Washington, DC.
. 1998. Growing Greener. National Land Trust, Media, PA.
Arendt, R., E.A. Brabec, H. L. Dodson, C. Reid, and R.D. Yaro. 1994. Rural by Design.
Planners Press, Chicago.
Baker,J.P., H. Olem, C.S. Creager, M.D. Marcus, and B.R. Parkhurst. 1993. Fish and
Fisheries Management in Lakes and Reservoirs. EPA 841-R-93-002. Terrene
Institute and U.S. Environmental Protection Agency, Washington DC.
Caduto, M. 1985. Pond and Brook. Prentice-Hall, Englewood Cliffs, NJ.
Center for Watershed Protection. 1998a. Better Site Design: A Handbook for
Changing Development Rules in Your Community. Ellicott City, MD.
. 1998b. Rapid Watershed Planning Handbook: A Comprehensive Guide for
Managing Urbanizing Watersheds. Ellicott City, MD.
Cwikiel, W. 1996. Living with Michigan's Wetlands: A Landowners Guide. Tip of the
Mitt Watershed Council, Conway, Ml.
Dresen, M.D. and R.M. Korth. 1994. Life on the Edge ... Owning Waterfront Property.
Wis. Dep.Natural Resour., Madison.
Engel.S. 1989. Lake use planning in local efforts to manage lakes. Pages 101-5 in Proc.
Natl. Conf. Enhancing States Lake Management Programs, May 1988. Northeast
III. Plann. Commiss. Chicago.
Ewing, R., M. DeAnna, C. Heflin, D. Porter. 1996. Best Development Practices.
Planners Press, Chicago.
Fuller, D. 1997. Understanding, Controlling, and Living With Shoreline Erosion. Tip of
the Mitt Watershed Council, Conway, Ml.
Hendler, B. 1977. Caring for the Land. American Society of Planning Officials,
Chicago.
365
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Managing Lakes and Reservoirs
Henderson, C. 1981. Landscaping for Wildlife. Minnesota Dep. Natural Resour., St.
Paul.
Jeffries, M. and D. Mills. 1990. Freshwater Ecology: Principles and Applications.
Belhaven Press, New York.
Lease, F. 1995. Designing a data management system. In The Volunteer Monitor 7( I).
Long Island Regional Planning Board. 1984. Nonpoint Source Management Handbook.
Long Island, NY.
Marsh, W. 1998. Landscape Planning Environmental Applications. 3rd ed.John Wiley
& Sons, Inc., New York.
McComas, S. 1993. Lake Smarts. Terrene Institute, Alexandria, VA.
McHarg, I. 1992. Design With Nature. John Wiley & Sons, Inc., Garden City, NJ.
Mitchell, M. and W. Stapp. 1994. Field Manual for Water Quality Monitoring. 8th ed.
Thomson-Shore, Inc., Dexter, Ml.
New York State Department of Environmental Conservation and Federation of Lake
Associations. 1990. Diet for a Small Lake: A New Yorker's Guide to Lake
Management. Albany, NY.
Novotny, V. and G. Chesters. 1981. Handbook of Nonpoint Source Pollution: Sources
and Management. Van Nostrand Reinhold Environmental Engineering, New York.
Novotny, V. and H. Olem. 1994. Water Quality: Prevention, Identification, and
Management of Diffuse Pollution. Van Nostrand Reinhold, New York.
Phillips, N., M. Kelly, J. Taggart and R. Reeder. 2000. The Lake Pocket Book. Terrene
Institute, Alexandria, VA.
Simpson,J.T. 1991. Volunteer Lake Monitoring: A Methods Manual. EPA 440/4-91-002.
Washington, DC. Available on www.epa.gov/owow/monitoring/volunteer/lake/
index.html.
Small, S. 1992. Preserving Family Lands: Essential Tax Strategies for the Landowner.
Landowner Planning Center, Boston.
Tip of the Mitt Watershed Council. 1999. Planning for Success. Conway, Ml.
The Volunteer Monitor. 1993-present. River Network, Portland, OR. See
www.epa.gov/owow/volunteer/vm_index.html
U.S. Environmental Protection Agency. 1996. A Volunteer Monitor's Guide to Quality
Assurance Project Plans. EPA 841 -B-96-003. Www.epa.gov/owow/monitoring/
volunteer/qappcovr.htm. Washington, DC.
Wetzel, R. 1975. Limnology. W.B. Saunders Company, Philadelphia.
Wyckoff, M. 1995. Regulating Keyhole Development: Carrying Capacity Analysis and
Ordinances Providing Lake Access Regulations. Planning Zoning Center, Inc.,
Lansing, Ml.
366
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APPENDIX 9-A
Example of
Lake Association Bylaws
BYLAWS OF MUDD LAKE PRESERVATION ASSOCIATION
A Michigan Nonprofit Corporation
I. NAME AND PURPOSE
I. Name: The name of this nonprofit corporation shall be Mudd Lake
Preservation Association.
2. Purpose: The corporation is organized to operate exclusively for
charitable, scientific, and educational purposes within the meaning of
Section 50l(c)(3) of the Internal Revenue Code, and more specifically:
a. To preserve and improve Mudd Lake and its watershed for quality
use by future generations.
b. To preserve natural and scenic areas, and recreational resources.
c. To carry on activities permitted by exempt organizations under
Section 501 (c)(3) of the Internal Revenue Code, as amended.
II. BOARD OF TRUSTEES
I. Responsibilities: The Board of Trustees established practices for this
nonprofit corporation and to elect the Board of Trustees and the
Officers. The Board of Trustees shall function as a board of directors
under Michigan Law.
2. Number: The Board of Trustees shall determine how many Board of
Trustee members are to be elected.
3. Term: Each Board of Trustees members shall serve for a term of two
years. A person may serve for more than one term.
4. Election: The Board of Trustees members may be elected at an annual
meeting of the Board of Trustees. In the absence of election, the existing
Board of Trustees shall continue. The incoming Board of Trustees shall
be elected by the preceding Board of Trustees. A member of the Board
of Trustees may vote for himself or herself.
5. Quorum: If there are seven or fewer Board of Trustees members, fifty
percent (50%) of the members of the Board of Trustees shall constitute
a quorum. If there are over seven Board of Trustees members, then one
third (1/3) of the Board of Trustees shall constitute a quorum (Michigan
Codified Laws, M.C.L 450.2523).
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Managing Lakes and Reservoirs
6. Voting: For all matters coming before the Board of Trustees, a majority
vote of those present at a meeting at which a quorum is present shall
govern. Procedures will be by Roberts Rules of Order.
7. Vacancy: In the event of a vacancy on the Board of Trustees, the
President shall have the right to appoint another Board of Trustees
member.
8.
9.
Qualifications: To be a member of the Board of Trustees, a person
must be recognized as a member of the Mudd Lake Preservation
Association.
Disqualification: A Board of Trustees member having three
consecutive unexcused Board of Trustees meeting absences shall be
terminated from serving on the Board of Trustees.
10. Ad Hoc Committee(s): The President may appoint ad hoc advisory
committees for any purpose.
11. Termination: Two-thirds (2/3) of the Board of Trustees (not merely a
quorum) shall have authority to terminate a person's position on the
Board of Trustees. Good cause for termination is not required.
III. OFFICERS
I. Officers: The officers shall consist of a President, one or more Vice
Presidents and Secretaries, and a Treasurer.
2. Term: The officers shall serve for a term of one year. Officers may be
elected to serve for more than one term.
3. Elections: The officers shall be elected from and by the Board of
Trustees following the election of Board of Trustees members. Elections
may be held at the Annual Meeting. If an election is not conducted, the
existing officers shall remain in office.
4. Duties: The duties of the officers shall be such as are implied by their
respective titles. The President shall preside over all meetings and may
attend all committee meetings. The Vice-President shall preside in the
absence of the President. The Secretary shall keep the roll of sponsors
and members, the minutes of all meetings, and shall maintain committee
reports. The Secretary shall also tend to all correspondence designated
by the Board. The Treasurer shall collect the dues, all other monies, pay
the bills, and oversee filing of all appropriate government reports and
forms. The Treasurer shall maintain an itemized account of all receipts
and disbursements.
IV. MEMBERSHIP
I. Qualifications: Membership shall be open to all persons having an
interest in and who support the mission of this nonprofit corporation.
2. Membership Dues: Dues, if any, shall be established by the Board of
Trustees.
3. Applications: Applications for membership may be on a form
prescribed by the Board of Trustees. An application for membership is
not required.
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APPENDIX 9-A: Example of Lake Association By-laws
4. Qualifications: Persons, families, or entities contributing dues shall be
recognized as members, subject to the discretion of the Board of
Trustees.
5. Board of Trustees Members: Only individual members may be
elected to the Board of Trustees.
6. Directorship Basis: As this nonprofit corporation is formed on a
directorship basis, the members will have no formal vote in corporate
affairs.
V. MEETINGS
I. Regular Meetings: Regular meetings shall be held at such times and
places as may be stated by the Board of Trustees.
2. Annual Meetings: Annual meetings shall be held at a time and location
to be determined by the Board of Trustees.
3. Special Meetings: Special meetings may be called by the President, on
48 hours notice, by phone, fax, or by first class mail. The notice shall
specify the purpose of the special meeting. Actual receipt of the fax or
mail is not required. Service shall be deemed effective when the fax is
sent or the letter is deposited with the U.S. Postal Service.
4. Consent Actions: The Board of Trustees may act by a consent action
signed by a majority of the members of the Board of Trustees. Written
consents shall be filed with the Board of Trustees minutes (Michigan
Codified Law, M.C.L 450.2525).
5. Presence: A person may be deemed present at a Board of Trustees
meeting when participating by phone, fax, or other means which would
necessarily require the personal presence of all Board of Trustees
members.
VI. AMENDMENTS
I. Procedure: The Bylaws may be amended by a majority of the Board of
Trustees present at a meeting at which a quorum is present.
2. Effective Time: Amendments to the Bylaws shall be effective
immediately upon the vote of the Board.
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Monogfng Lakes and Reservoirs
370
-------
Appendix A
Glossary
T
!his Glossary defines commonly used terms and important processes and
concepts relating to lakes and lake management. To provide further detail,
items have been cross-referenced.
Acid neutralizing capacity (ANC): the equivalent capacity of a solution to neu-
tralize strong acids. The components of ANC include weak bases (carbonate spe-
cies, dissociated organic acids, alumino-hydroxides, borates, and silicates) and
strong bases (primarily, OH). In the National Surface Water Survey, as well as in
most other recent studies of acid-base chemistry of surface waters, ANC was
measured by the Gran titration procedure.
Acid rain: rainfall that contains acidic chemicals, such as nitric acid from automobile
emissions and sulfuric acid that have escaped into the air from burning fossil fuels.
Acidic deposition: transfer of acids and acidifying compounds from the atmosphere
to terrestrial and aquatic environments via rain, snow, sleet, hail, cloud droplets,
particles, and gas exchange.
Adsorption: the adhesion of one substance to the surface of another; clays, for exam-
ple, can adsorb phosphorus and organic molecules.
Aerobic: describes life or processes that require the presence of molecular oxygen.
Algae: small aquatic plants that occur as single cells, colonies, or filaments. They con-
tain chlorophyll but lack special water-carrying tissues. Through the process of
photosynthesis, algae produce most of the food and oxygen in water environ-
ments.
Algal: of or related to algae.
Allochthonous: materials (e.g., organic matter and sediment) that enter a lake from
atmosphere or drainage basin. See Autochthonous.
Anaerobic: describes processes that occur in the absence of molecular oxygen.
Anoxia: a condition of no oxygen in the water. Often occurs near the bottom of fer-
tile, stratified lakes in the summer and under ice in late winter.
Aphotic zone: that area of the lake too dark to support photosynthesis.
Aquatic life: organisms that live and grow in, or frequent, water.
Aquifer: an underground, water-bearing bed of permeable rock, sand, or gravel. Aqui-
fers contain large amounts of groundwater that feed into wells and springs.
Autochthonous: materials produced within a lake; e.g., autochthonous organic mat-
ter from plankton versus allochthonous organic matter from terrestrial vegetation.
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Managing Lakes and Reservoirs
Bacteria: a large group of microscopic organisms of many different shapes, generally
without chlorophyll. Some bacteria are helpful (as in a fermentation process), but
certain species can cause diseases such as swimmer's itch, pneumonia, or typhoid
fever, among others.
Bareground banks: river or stream banks that have no vegetation (no plant cover-
ing) to hold the soil against erosive action.
Bath/metric map: a map showing the bottom contours and depth of a lake; can be
used to calculate lake volume.
Benthic: refers to life or things found on the bottom of a lake. Examples: benthic ani-
mals, benthic sediments.
Benthos: macroscopic (seen without aid of a microscope) organisms living in and on
the bottom sediments of lakes and streams. Originally, the term meant the lake
bottom, but it is now applied almost uniformly to the animals associated with the
substrate.
Berm: a narrow shelf, ledge, or barricade, typically at the top or bottom of a slope; a
mound or wall of earth; for example, small dams or ridges.
Best management practices (BMPs): systems, activities, and structures that hu-
man beings can construct or practice to prevent nonpoint source pollution.
Biochemical oxygen demand (BOD): the rate of oxygen consumption by organ-
isms during the decomposition (see Respiration) of organic matter, expressed as
grams oxygen per cubic meter of water per hour.
Biodiversity: a multiplicity of different, mutually dependent living things characteristic
of a particular region or habitat.
Biomass: the weight of biological matter. Standing crop is the amount of biomass (e.g.,
fish or algae) in a body of water at a given time. Often measured in terms of grams
per square meter of surface.
Biota: all plant and animal species occurring in a specified area.
Cadmium: bluish-white toxic metal or metallic element used especially in protective
plating and in bearing metals.
Chemical oxygen demand (COD): nonbiological uptake of molecular oxygen by
organic and inorganic compounds in water.
Chlorophyll a: A type of chlorophyll present in all types of algae, sometimes in direct
proportion to the biomass of algae.
Chlorophyll: a green pigment in algae and other green plants that is essential for the
conversion of sunlight, carbon dioxide, and water to sugar (see Photosynthesis).
Sugar is then converted to starch, proteins, fats, and other organic molecules.
Clarifier tanks: holding tanks associated with wastewater and sewage treatment
centers. Wastewater in these tanks is treated to remove harmful substances be-
fore being released into a watershed.
Clean Water Act: the federal Clean Water Act of 1972 (formerly referred to as the
Federal Water Pollution Control Act): requires the development of comprehen-
sive programs for preventing, reducing, or eliminating the pollution and improving
the condition of the nation's navigable, surface, and groundwaters.
Cluster development: placement of housing and other buildings of a development
in groups to provide larger areas of open space.
Coliform: a bacteria carried in human and animal wastes.
372
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APPENDIX A; G/OSSQfy
Combined sewer overflow (CSO): what happens when too much stormwater
flows into drainage systems that also contain wastewater effluent. The combined
flow from the stormwater and wastewater may result in releases of untreated
wastewater directly into lakes, rivers, or streams. This is most common in older sys-
tems since most modern drainage systems separate stormwater and wastewater
flows. (CSOs refer to overflows before the water reaches the treatment plant.)
Comparability: this is often very important for citizen monitoring programs because
it represents how well data from one lake compare to data from another. For ex-
ample, state and regional agencies and local monitors should work together to es-
tablish standard sampling methods and procedures for volunteer monitoring
programs.
Compliance officer: one who plans, manages, or oversees a company's submission
to laws, regulations, and practices; a person delegated to ensure a company's con-
formity with the law.
Compliance: the act of fulfilling an official requirement; submission to operative laws,
regulations, practices, terms, or conditions.
Compost: a mixture of soil and decayed organic matter (food, vegetative, and animal
wastes) used for fertilizing and conditioning land.
Conservation easement: (also known as conservation restrictions) are legal agree-
ments between a landowner and a qualified government agency or nongovernmental
organization (most commonly a land trust) that permanently limit a property's uses;
they remain with it if it is sold. A conservation easement does not transfer title to
the property or open it to the public. The landowner continues to own the prop-
erty, and may live on it, sell it, or pass it on to heirs.
Conservation tillage: a practice or method of plowing in which crop residue is left
on the field as protective mulch or cover instead of being plowed under.
Consumers: animals that cannot produce their own food through photosynthesis
and must consume plants or animals for energy. S.ee Producers.
Decomposition: the transformation of organic molecules (e.g., sugar) to inorganic
molecules (e.g., carbon dioxide and water) through biological and non-biological
processes.
Delphi: a technique that solicits potential solutions to a problem situation from a
group of experts and then asks the experts to rank the full list of alternatives.
Denitrification: the process by which nitrate in water or sediments is converted to
nitrogen gas, which is then lost to the atmosphere.
Density flows: a flow of water of one density (determined by temperature or salin-
ity) over or under water of another density (e.g., flow of cold river water under
warm reservoir surface water).
Detritus: organic material composed of dead plants or animals, or parts thereof (e.g.,
leaves, grass clippings) that settle to the bottom of a lake. Bacteria and fungi slowly
decompose detritus, thus recycling it back into the lake's ecosystem.
Drainage basin: land area from which water flows into a stream or lake. See Water-
shed. ,
Drainage lakes: lakes having a defined surface inlet and outlet.
Ecology: a branch of science concerned with the interrelationship of organisms with
their environment.
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Managing Lakes and Reservoirs
Ecoregion: Comprised of relatively homogenous ecological systems delineated by
geology, soils, climate, vegetation, and landform, and involving interrelationships
among organisms and their environment.
Ecosystem: a system of interrelated organisms and their physical-chemical environ-
ment. In this manual.the ecosystem is usually defined to include the lake and its wa-
tershed.
Effluent: liquid wastes from sewage treatment, septic systems, or industrial sources
that are released to a surface water.
Environment: the complex of one's surroundings; the climatic, soil-related, and
life-related factors that act on organisms or ecological communities and ultimately
determine their form and survival.
Environmental movement: an organized or grass roots, public, or private move-
ment or group acting to preserve the quality and continuity of life through the con-
servation of natural resources and the prevention and/or reduction of pollution.
Environmental Protection Agency (EPA): a division or office of government, ei-
ther federal or state, responsible for safeguarding and managing a region's natural
resources and quality of life. The U.S. EPA is an agency of the federal government;
the names of state EPAs vary.
Epilimnion: uppermost, warmest, well-mixed layer of a lake during summertime ther-
mal stratification. The epilimnion extends from the surface to the thermocline. See
Stratification.
Epiphytes: small plants or animals that grow attached to larger plants.
Erosion: the gradual wearing down of land by water, wind, or melting snow. Soil losses,
for example, from streambanks and forests, hilly ground, lawns, and farm fields.
Eutrophic: from Greek for "well-nourished": describes a lake of high photosynthetic
activity and low transparency. See Trophic State.
Eutrophication: the process of physical, chemical, and biological changes associated
with nutrient, organic matter, and silt enrichment and sedimentation of a lake or
reservoir that cause a water body to age. If the process is accelerated by human in-
fluences, it is termed cultural eutrophication.
Eutrophication cultural: human activities, such as discharge of sewage and storm-
water, and nonpoint source pollutants, can dramatically hasten the process of
eutrophication.
Fall overturn:the autumn mixing, top to bottom, of lake water caused by cooling and
wind-derived energy.
Fecal coliform test: most common test for the presence of fecal material from
warm-blooded animals. Fecal coliforms are measured because of convenience; they
are not necessarily harmful but indicate the potential presence of other dis-
ease-causing organisms.
Floodplain: land adjacent to lakes or rivers that is covered as water levels rise and
overflow the normal water channels.
Flushing rate: the rate at which water enters and leaves a lake relative to lake vol-
ume, usually expressed as time needed to replace the lake volume with inflowing
water.
Flux: the rate at which a measurable amount of a material flows past a designated
point in a given amount of time.
Food chain: the general progression of feeding levels from primary producers, to her-
bivores, to planktivores, to the larger predators.
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APPENDIX A: Glossary
Food web: the complex of feeding interactions existing among the lake's organisms.
Forage fish: Fish, including a variety of panfish and minnows, that are prey for game
fish.
Forest Service (FS): an agency of the federal government located within the De-
partment of Agriculture that manages and protects our forests, wooded areas, and
timber resources.
Groundwater:the supply of fresh water found beneath the earth's surface (usually in
aquifers); often used to supply drinking water to wells and springs; may be con-
nected to lakes.
Habitat: the physical environment or typical place within which a plant or animal nat-
urally or normally lives and grows.
Hydrographic map: a map showing the location of areas or objects within a lake.
Hydrologic cycle: the circular flow or cycling of water from the atmosphere to the
earth (precipitation) and back to the atmosphere (evaporation and plant transpira-
tion). Runoff, surface water, groundwater, and water infiltrated in soils are all part
of the hydrologic cycle.
Hypolimnion: lower, cooler layer of a lake during summertime thermal stratification.
See Stratification.
Influent: a tributary stream.
Internal nutrient cycling: transformation of nutrients such as nitrogen or phospho-
rus from biological to inorganic forms through decomposition, occurring within
the lake itself.
Isothermal: the same temperature throughout the lake.
Lake: a considerable inland body of standing water, either naturally formed or built by
humans.
Lake district: a special purpose unit of government with authority to manage a
lake(s) and with financial powers to raise funds through mill levy, user charge, spe-
cial assessment, bonding, and borrowing. May or may not have police power to in-
spect septic systems, regulate surface water use, or zone land.
Lake management: the practice of keeping lake quality in a state such that attain-
able uses can be achieved.
Lake protection: the act of preventing degradation or deterioration of attainable
lake uses.
Lake restoration: the act of bringing a lake back to its attainable uses.
Lentic: relating to standing water (versus lotic, running water).
Limnetic zone: also called Epilimnion. See Stratification.
Limnology: the scientific study of the physical, chemical, geological, and biological fac-
tors that affect aquatic productivity and water quality in freshwater ecosystems —
lakes, reservoirs, rivers, and streams.
Limnologist: one who practices limnology.
Littoral zone: the shallow zone along the shore of a lake; that portion of a water
body extending from the shoreline lakeward to the greatest depth occupied by
rooted plants. Plants growing here support a rich biological community.
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Managing Lakes and Reservoirs
Loading: the total amount of material (sediment, nutrients, oxygen-demanding mate-
rial) brought into the lake by inflowing streams, runoff, direct discharge through
pipes, groundwater, the air, and other sources over a specific period of time (often
annually).
Macroinvertebrates: aquatic insects, worms, clams, snails, and other animals visible
without aid of a microscope, that may be associated with or live on substrates such
as sediments and macrophytes. They supply a major portion of fish diets and con-
sume detritus and algae.
Macrophytes: plants large enough to be seen without magnification. Some forms,
such as duckweed and coontail (Ceratophyllum), are free-floating forms without,
roots in the sediment.
Mandatory property owners association: organization of property owners in a
subdivision or development with membership and annual fee required by cove-
nants on the property deed. Association will often enforce deed restrictions on
members' property and may have common facilities such as bathhouse, clubhouse,
golf course, etc.
Marginal zone: area where land and water meet at the perimeter of a lake. Includes
plant species, insects, and animals that thrive in this narrow, specialized ecological
system.
Meaningful indicators: link objectives to management objectives; are meaningful to
stakeholders; are measurable, or ranked subjectively; and can be predicted.
Mercury: a heavy silver-white poisonous metallic element sometimes found as a con-
taminant in rainfall.
Mesotrophic: the medium range of eutrophication. See Trophic State.
Metalimnion: layer of rapid temperature and density change in a thermally stratified
lake; lies between epilimnion and hypolimnion. Resistance to mixing is high in the
region. See Stratification.
Minimum tillage: a practice of plowing or turning the soil only enough to plant new
crops, while leaving plant residue on the surface as compost.
Morphometry: relating to a lake's physical structure (e.g., depth, shoreline length).
Mulch: a protective covering (as of sawdust, compost, or paper) spread or left on the
ground. Mulch prevents evaporation, maintains even soil temperature, prevents
erosion, controls weeds, and enriches the soil.
National Pollutant Discharge Elimination System (NPDES):federal operating
permits issued by EPA to industrial and municipal facilities to help these facilities
comply with the Clean Water Act.
Natural Resources Conservation Service (NRCS): a federal agency responsible
for safeguarding and managing soil and water resources. NRCS operates within the
Department of Agriculture and maintains local offices throughout the country.
Nekton: large aquatic and marine organisms whose mobility is not determined by
water movement—for example, fish and amphibians.
NEPA:The National Environmental Policy Act of 1969 that established a national pol-
icy for the environment, created the Council on Environmental Quality, and di-
rected that every recommendation or report on proposals for legislation and
other major federal actions significantly affecting the quality of the human environ-
ment include a detailed statement on the environmental impact of the proposed
action. For the complete act, see Council on Environmental Quality, 1991.
NOAA: National Oceanic and Atmospheric Administration
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APPENDIX A: Glossary
Nominal group process: a process of soliciting concerns/issues/ideas from mem-
bers of a group and ranking the resulting list to ascertain group priorities. Designed
to neutralize dominant personalities.
Noncompliance: a condition of not submitting to applicable laws, regulations, terms,
or conditions.
Nonpoint source (NPS): pollution that cannot be traced to a specific origin or
starting point, but seems to flow from many different sources. NPS pollutants are
generally carried off the land by stormwater (or melting snow) runoff. The com-
monly used categories for nonpoint sources are agriculture,forestry, urban, mining,
construction, dams and channels, land disposal, and saltwater intrusion.
Nutrient: an element or chemical essential to life, such as carbon, oxygen, nitrogen,
and phosphorus.
Nutrient budget: quantitative assessment of nutrients (e.g., nitrogen or phosphorus)
moving into, being retained in, and moving out of an ecosystem; commonly con-
structed for phosphorus because of its tendency to control lake trophic state.
Nutrient cycling: the flow of nutrients from one component of an ecosystem to an-
other, as when macrophytes die and release nutrients that become available to al-
gae (organic to inorganic phase and return).
Nutrients: substances or ingredients that nourish or promote growth and repair the
natural destruction of organic life.
Oligotrophic: "poorly nourished," from the Greek. Describes a lake of low plant pro-
ductivity and high transparency. See Trophic State.
Ooze: lake bottom accumulation of inorganic sediments and the partially decom-
posed remains of algae, weeds, fish, and aquatic insects. Sometimes called muck. See
Sediment.
Ordinary high water mark: physical demarcation line, indicating the highest point
that water level reaches and maintains for some time. Line is visible on rocks, or
shoreline, and by the location of certain types of vegetation.
Organic: of, relating to, or derived from living things; relating to, produced with or
based on the use of plant and animal fertilizers rather than chemically formulated
fertilizers or pesticides.
Organic matter: molecules manufactured by plants and animals and containing
linked carbon atoms and elements such as hydrogen, oxygen, nitrogen, sulfur, and
phosphorus.
Paleolimnology: the study of lake sediments and the relics preserved in them.
Pathogen: a microorganism capable of producing disease. They are of great concern
to human health relative to drinking water and swimming beaches.
Pelagic zone: the open area of a lake, from the edge of the littoral zone to the center
of the lake.
Perched: a condition where the lake water is isolated from the groundwater table by
impermeable material such as clay.
Permeable: a surface or material that has pores or openings that allow liquids to
penetrate or pass through.
Pesticide: an agent used to destroy insects and other pests.
pH: a measure of the concentration of hydrogen ions of a substance, which ranges
from very acid (pH = I) to very alkaline (pH = 14). pH 7 is neutral and most lake
waters range between 6 and 9. pH values less than 6 are considered acidic, and
most life forms cannot survive at pH of 4.0 or lower.
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Managing Lakes and Reservoirs
Photic zone: the lighted region of a lake where photosynthesis takes place. Extends
down to a depth where plant growth and respiration are balanced by the amount
of light available.
Photosynthesis: a chemical reaction that occurs only in plants. Plants use a green
pigment called chlorophyll to convert water and carbon dioxide into cellular mate-
rial and oxygen in the presence of light. Hence, photosynthesis occurs only during
daylight hours.
Phytoplankton: microscopic algae and microbes that float freely in open water of
lakes and oceans. In some lakes, they provide the primary base of the food chain for
all animals. They also produce oxygen by a process called photosynthesis.
Phytoremediation: plants are used to clean up certain types of heavily contami-
nated soils by absorbing the contaminants from the soil.
Plankton: small, mostly microscopic plants and animals that are too small to outswim
most currents, so the movement of water tends to move them from place to place.
Plankton consists of phytoplankton (planktonic plants) and zooplankton (plank-
tonic animals).
Plankton rain: the almost constant settling of plankton, live and dead, through the
water to the bottom sediments.
Plantivores: fish and invertebrate that collectively prey on zooplankton.
Point source (PS): pollution discharged into water bodies from specific, identifiable
pipes or points, such as an industrial facility or municipal sewage treatment plant.
Pollutants: solid, liquid, or gaseous substances that contaminate the local or general
environment.
Pollution: the condition of being polluted. A generic word for any type of contamina-
tion of water, land, or air.
Precipitation: a water deposit on earth in the form of hail, rain, sleet, and snow.
Primary productivity: the rate at which algae and macrophytes fix or convert light,
water, and carbon dioxide to sugar in plant cells. Commonly measured as milli-
grams of carbon per square meter per hour.
Producers: green plants that manufacture their own food through photosynthesis.
Profundal zone: mass of lake water and sediment occurring on the lake bottom be-
low the depth of light penetration. Also called Hypolimnion. See Stratification.
Reservoir: lake created by artificially damming a stream or river where water is col-
lected and kept in quantity for a variety of uses, including flood control, water sup-
ply, recreation, and hydroelectric power.
Residence time: commonly called the hydraulic residence time — the amount of
time required to completely replace the lake's current volume of water with an
equal volume of "new" water.
Respiration: process by which organic matter is oxidized by organisms, including
plants, animals, and bacteria. The process releases energy, carbon dioxide, and wa-
ter.
Runoff: that portion of precipitation that flows over the land carrying with it such
substances as soil, oil, trash, and other materials until it ultimately reaches streams,
rivers, lakes, or other water bodies.
Secchi depth: a measure of transparency of water (the ability of light to penetrate
water) obtained by lowering a black and white, or all white, disk (Secchi disk, 20 cm
in diameter) into water until it is no longer visible. Measured in units of meters or
feet.
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APPENDIX A: Glossary
Secchi disk: a white or black and white disk used to measure transparency of water.
See Secchi depth.
Sediment: bottom material in a lake that has been deposited after the formation of a
lake basin. It originates from remains of aquatic organisms, chemical precipitation of
dissolved minerals, and erosion of surrounding lands. See Ooze.
Sediment oxygen demand (SOD): after a long time, plant and algal cells that die
can sink to low places in a lake where they begin to decompose, eventually accu-
mulating as a thick layer of soft, highly organic sediments. This decomposition by
bacteria uses oxygen from the overlying water, and thus, can drain a lake's dissolved
oxygen. If accidentally resuspended (as in a storm or by power boats), these sedi-
ments can kill fish and other animals. When bottom dissolved oxygen falls too low,
millions of small invertebrates (animals without backbones) living in and on the
bottom may also be reduced or even eliminated.
Seepage lakes: lakes having either an inlet or outlet (but not both) and generally ob-
taining their water from groundwater and rain or snow.
Septic tank: a holding tank for collecting residential wastewaters. Used as an alterna-
tive to municipal sewer systems in some areas. Wastewater collected in septic
tanks disperses into the soil through a septic drainfield.
Sewage treatment plant: a facility (usually municipal) that treats sewer waste to re-
move harmful substances before discharge.
Soil retention capacity: the ability of a given soil type to adsorb substances such as
phosphorus, thus retarding their movement to the water.
Spawning: the production and deposit of eggs by fish within their aquatic habitat.
Standing crop: the amount of biomass (e.g., fish or algae) in a body of water at a
given time.
Stratification: process in which several horizontal water layers of different density
may form in some lakes. During stratification, the bottom mass (hypolimnion or
profundal zone) is cool, high in nutrients, low in light, low in productivity, and low in
dissolved oxygen. The top mass (epilimnion or limnetic zone) is warm, higher in
dissolved oxygen, light, and production, but lower (normally) in nutrients. The
sharp boundary between the two masses is called a thermocline. The metalimnion
exists in this area.
Swimmer's itch: a rash caused by penetration into the skin of the immature stage
(cercaria) of a flatworm (not easily controlled due to complex life cycle). A shower
or alcohol rubdown should minimize penetration.
Thermal stratification: lake stratification caused by temperature-created differ-
ences in water density.
Thermocline: a horizontal plane across a lake at the depth of the most rapid vertical
change in temperature and density in a stratified lake. See Metalimnion and Stratifi-
cation.
Tillage: the operation of plowing or cultivating land.
Topographic map: a map showing the elevation of the landscape at fixed contour in-
tervals, usually 2,5, 10, or 20 feet. This information can be used to delineate a wa-
tershed.
Toxic: poisonous substances harmful to living things. Of, relating to, or caused by poi-
son.
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Managing Lakes and Reservoirs
Trophic state: the degree of eutrophication of a lake. Transparency, chlorophyll a lev-
els, phosphorus concentrations, amount of macrophytes, and quantity of dissolved
oxygen in the hypolimnion can be used to assess trophic state.
Trophic state index: a number used to categorize lakes as oligo-, meso-, or
eutrophic, on a scale generally from I to 100: the higher the number, the more
eutrophic. It can be calculated a variety of ways, using chlorophyll (a measure of al-
gae abundance), Secchi depth (an indirect measure of algae abundance by measur-
ing water clarity), or nutrients. Lakes with TSI of 60 or more are considered
eutrophic.
Turbid: thick or cloudy with sediment.
Turbidity: cloudiness; characterized by obscurity.
Upset: a waste/sewage treatment plant malfunction. In an upset, untreated or incom-
pletely treated wastewater enters the watershed.
USDA: U.S. Department of Agriculture
USFS: U.S. Forest Service, a USDA agency
USGS: U.S. Geological Survey
Vegetative/vegetation filter strips: plantings used to trap water (and the sub-
stances it carries) to prevent it from running off the land; a BMP that helps prevent
nonpoint source pollution.
Voluntary lake property owners association: organization of property owners in
an area around a lake that members join at their option.
Wastewater treatment plant: sometimes synonymous with sewage treatment
plant, but often an industrial treatment facility that processes the water to remove
toxic and hazardous wastes.
Water body: a land basin filled with water. Any river, lake, stream, or ocean that re-
ceives runoff waters from a watershed.
Water column: water in the lake between the interface with the atmosphere at the
surface and the interface with the sediment layer at the bottom. Idea derives from
vertical series of measurements (oxygen, temperature, phosphorus) used to char-
acterize lake water.
Water hardness: originally defined as the capacity of water to preciptate soap, water
hardness is now defined as the sum of the calcium and magnesium concentrations,
both expressed as calcium carbonate, in mg/L.
Water table: the upper surface of groundwater; below this point, the soil is saturated
with water.
Watershed: a drainage area or basin in which all land and water areas drain or flow
toward a central collector such as a stream, river, or lake at a lower elevation.
Wetlands: lands or areas, such as tidal flats or swamps, that are often or periodically
saturated with water. Wetlands contain much soil moisture and plants that grow
well in that condition.
Zooplankton: microscopic animals that float freely in lake water, graze on detritus
particles, bacteria, and algae, and may be consumed by fish.
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Appendix B
Metric Units
COMMON UNITS OF MEASURE IN LAKE MANAGEMENT
Limnology, the primary science upon which lake management is based, uses metric
units in professional publications. Although most units in this Manual are expressed
in British/U.S. form, the reader is strongly encouraged to become more
comfortable with common metric units — they are far easier to manipulate, and
any further encounter with the literature and books on lake management will entail
using the metric system of measurement.
The following table compares the two systems; to convert English units to metric,
use the conversion factors supplied in this table.
METRIC TO ENGLISH CONVERSIONS
METRIC UNIT
SYMBOL
ENGLISH UNIT
CONVERSION FACTOR*
LENGTH
Millimeter
Centimeter
Meter
Kilometer
WEIGHT
Microgram
Milligram
Gram
Kilogram
VOLUME
Milliliter
Liter
Kiloliter
(cubic meter)
mm = 0.001 m
cm = 0.01 m
m = 1.0 m
km =1000 m
,ug = 0.000001 g
mg = 0.001 g
g = 1.0 g
kg =1000g
mL = 0.001 L
L= l.OL
kL= 1000 L
inch 0.03937
inch 0.3937
yard 1.094
mile 0.6214
(no reasonable equivalent)
grain 0.015432
ounce (avoir) 0.03527
pound 2.205
ounce 29.57
quart 1.057
cu. yard 1.308
' To convert metric to English units, multiply by factor.
OTHER USEFUL CONVERSIONS
1 gallon = 3.785 liters
1 milligram/liter = 1 part per million
1 hectare = 2.47 acres
1 acre-foot = 32,590 gallons
1 cubic meter = 264 gallons
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Managing Lakes and Reservoirs
382
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ISBN 1-880686-15-5
EPA 841 -B-01 -006
Copies are available from
North American Lake Management Society
P.O. Box 5443
Madison.Wl 53705
phone: (608) 233-2836
fax:(608)233-3186
nalms@nalms.org
www.nalms.org
and the
Terrene Institute
4 Herbert Street
Alexandria.VA 22305
phone: (800) 726-4853
fax: (703) 548-6299
info@terrene.org
www.terrene.org
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