United States
Environmental Protection
Agency
Office of Water(WH-553)
Washington, DC 20460
EPA-440/4-90-006
August 1990
The Lake and Reservoir
Restoration Guidance
. _ t, » \ s
Manual
Second Edition
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Lake and Reservoir Restoration
Guidance Manual
-..-:. Prepared by the
NORTH AMERICAN LAKE MANAGEMENT SOCIETY
o.••• ';-..•;.. -;:••,-,,:-
. for the
U.S. Environmental Protection Agency
Office of Water
Assessment and Watershed Protection Division
Nonpoint Sources Branch
Washington, D.C.
Second Edition
1990
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EPA 440/4-90-006
The Manual was prepared by the North American Lake Management Society under EPA
Cooperative Agreement No. CX-814969. .
Cover photograph courtesy of Harvey Olem, Olem Associates, Inc.,
Citation: Olem, H. and G. Flock, eds. 1990. Lake and Reservoir Restoration
Guidance Manual. 2nd edition. EPA 440/4-90-006. Prep, by N. Am. Lake
Manage. Soc. for U.S. Environ. Prot. Agency, Washington, DC.
A
Points of view expressed in this technical supplement do not necessarily reflect
the views or policies of the U.S. Environmental Protection Agency and the North
American Lake Management Society nor of any of the contributors to its publica-
tion. Mention of trade names and commercial products does not constitute en-
dorsement of their use. .
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PREFACE
Just as lakes are continually evolving bodies of water, so are .the
methods developed to protect, restore, and manage them.. For that
reason, in the Water Quality Act of 1987 Congress mandated that
the Lake and Reservoir Restoration Guidance Manual be updated every
two years.
Readers will note many differences in this, the second edition:-addi-
tions, changes, new information. This is the product of careful review
.and rewrite by the authors of each chapter. Both the side notes and the
index have also been expanded, as have the appendices.
A companion volume, Monitoring Lake and Reservoir Restoration,
is being published simultaneously as the first in a series of technical
supplements to this Manual.
Your suggestions are welcomed by the Clean Lakes Program staff as
they continue the updating process and the development of further tech-
nical supplements. Please address your comments and requests for the
manuals to: -
Clean Lakes Program
Assessment'and Watershed Protection Division (WH-553)
U.S. Environmental Protection Agency
401 M St. SW
Washington, DC 20460
iii
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A ckn owl edge merits
This second edition of the Manual was prepared under the guidance of Kent W.
Thornton, Ph.D., who also managed the production of the first edition, for which he
and Lynn Moore served as editors. The authorship for each chapter includes:
CHAPTER 1: OVERVIEW OF MANUAL
Kent W. Thornton, Ph.D.
FTN Associates
tf i •
CHAPTER 2: ECOLOGICAL CONCEPTS
Bruce Kimmel, Ph.D.
Oak Ridge National Laboratory
CHAPTER 3: PROBLEM IDENTIFICATION . ; .
Lowell Klessig, Ph.D.
University of Wisconsin-Stevens Point
Richard Wedepohl, Ph.D.
Douglas Knauer, Ph.D. • * '
Wisconsin Department of Natural Resources
CHAPTER 4: PREDICTING LAKE WATER QUALITY
William W. Walker, Ph.D.
Environmental Consultant
CHAPTER 5: MANAGING THE WATERSHED
Kent W. Thornton, Ph.D. . • -
Forrest E. Payne, Ph.D.
FTN Associates .
CHAPTER 6: LAKE AND RESERVOIR RESTORATION AND
MANAGEMENT TECHNIQUES
Dennis Cooke, Ph.D.
Kent State University
Harvey Olem, Ph.D.
Olem Associates, Inc. ' • "
CHAPTER 7: HYPOTHETICAL CASE STUDY
Frank X. Browne, Ph.D.
EX. Browne Associates
CHAPTER 8: IMPLEMENTING THE MANAGEMENT PLAN
William Funk, Ph.D.
Washington State, University
CHAPTER 9: LAKE PROTECTION AND MAINTENANCE
Kent W. Thornton, Ph.D.
FTN Associates .
Editors: Harvey Olem, Ph.D., Olem Associates, Inc. and Gretchen
Flock, JT&A, Inc. .
iv
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CONTENTS
PREFACE ................................... ,iii
CONTENTS .,...............,..........;. v
ACKNOWLEDGEMENTS . . ,. ..... .xi
Chapter 1: Overview of Manual
Introduction . .1
Audience .1
Focus t ..... 2
Lakes as Resources ' 2
Natural Lake Conditions . . . , 2
. Desired Lake Uses ..>............... .3
What a Lake IS NOT 3
Defining Desired Uses , . 4
User Involvement .'....".•.'' , 4
Causes Versus Symptoms — A Major Reason for This Manual .4
Manual Organization . ....... . . . . .5
Definitions '. 6
Chapter 2: Ecological Concepts
Lake and Reservoir Ecosystems 7
The Lake and Its Watershed ;'..... ...'.... 9
Water ................ . . 9
Dissolved Materials 9
Special background section: The Hydroiogic Cycle . . . •-. 10
Special background section: Hydraulic Residence Time . . ... . . . . 11
Special background section: Regional Differences in Lake Water
Quality, Productivity, and Suitability . ... . . .'. '. . 13
Particulates . 14
Effects of Lake Depth 14
Man-Made Lakes 15
Lake Processes 16
Lake Stratification and Mixing '...... . 16
Mixing Processes 17
Special background section: The Unique Properties of Water ...... 18
Water Movements 20
Organic Matter Production and Consumption 21
Photosynthesis and Respiration ..................... 21
Phytoplankton Community Succession . . .23
•'•"-- . '• ' . • ' •' v
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Sedimentation and Decomposition . ... 23
Pood Web Structure, Energy Flow, and Nutrient Cycling 25
Lake Aging and Cultural Eutrophication 28
Special background section: Lake Basin Origin and Shape 30
Ecology's Place in Lake Protection, Restoration, and Management .... 31
Chapter 3: Problem Identification
Chapter Objectives . . . 35
Common Lake Problems 35
Algae 38
Weeds • 38
Depth 38
Acidity 38
User Conflicts .' . 39
Problem Statement 39
Problem Identification 40
Problem Perception 40
Causes of Lake Problems 41
Selecting a Consultant 42
Problem Diagnosis 43
Investigate the Problem : 43
Preliminary Analyses . .' . . 43
Data Collection and Analyses 46
Water Budget 46
Surface Water and Lake Level . 46
Groundwater Measurements 46
On-site Septic Systems 50
Water Quality Monitoring ,. . .51
Sampling Sites ... \ ...... ^ ...... . . 51
Physical Parameters . 52
Sedimentation Rate Estimates . . . . . . . . 52
Temperature 53
Transparency 54
Chemical Parameters 55
Dissolved Oxygen . 55
pH ........; 55
Alkalinity/Acid Neutralizing Capacity 55
Nutrients ' . . : 56
Biological Parameters . .". / " 56
Algal Biomass .57
Macrophyte Biomass and Locations . . . 57
Fish Survey .V. . . 59
Use of Trophic State Indices 59
Problem Definition . . 61
Putting the Pieces 'of the Puzzle Together 61
vi
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Mirror Lake . . . .-.' ; . , . . 61
Appendix 3-A: Democratic Procedures to Obtain Consensus on
Priority Uses for a Lake . ... ....;. .... . . ... 66
Nominal Group Process ........ 66
Chapter 4: Predicting Lake Water Quality
Uses of Models • • • • 69
Eutrophication Model Framework . 71
Variability ........ . . . . . •. .... . ... ........;.... 73
Loading Concept '. ....... 74
WaterBudget . . . ,75
Phosphorus Budget -76
Lake Response Models ........... . . ............... 8p
Tracking Restoration Efforts .".. . . . . ... ... 84
Case Studies . .-'.. ..... 87
Lake Washington, Washington: "You Should Be So Lucky" . . . ... .87
Onondaga Lake, New York: "Far Out. 93 Percent Is Not Enough" .... 87
Long Lake, Washington: "What's This? Reservoir Restoration?" .... 88
Shagawa Lake, Minnesota: "The Little Lake That Couldn't" 88
Kezar Lake, New Hampshire: "The Little Lake That Could (With a .
Little Help)", or "Shagawa Revisited ..."............ 88
Lake Money, Vermont: "Strange Mud ..." . . 89
" Wahnbach Reservoir, Germany: "When All Else Fails ..." 90
Lake Lillinonah, Connecticut: "You Can't Fool Mother Nature ..." ... 90
Chapter 5: Managing the Watershed
Introduction 93
The Lake-Watershed Relationship ............."..... 93
Point Sources . . -. . . . 94 •
Wastewater Treatment .....-., 95
Choosing the Scale of the System . 95
Municipal Systems 95
Small-Scale Systems .....:. .•'•••. 96
On-site Septic Systems 96
Community Treatment Facilities 100
Water Conservation to Reduce Lake Problems ............. . .103
How to Assess Potential Sources .104
Assessing Point and Domestic Wastewater Sources . . .... . . ... . . .105
Nonpoint Sources 105
Cultural Sources of Sediments, Organic Matter, and Nutrients . 106
What are Best Management Practices? '..... .107
Lake Restoration Begins in the Watershed . . . . 110
Guidelines and Considerations .112
vii
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Examples of Point and Nonpoint Improvement Projects . . -114
'* Lake Washington:. Point Source Diversion 114
Annabessacook Lake-, Cobbossee Lake, and Pleasant
Pond: Point-Source Diversion/Nonpoint Source Waste
Management/ln-Lake Treatments 114
East and West Twin Lakes: Septic Tank Diversion . . . . . . 115
Summary !-..-.. 115
Chapter 6: Lake and Reservoir Restoration and
Management Techniques
Introduction 117
The Principles of Restoration ; 117
Are Protection and Restoration Possible? . : 119
Lake and Reservoir Restoration and Management Techniques 120
Basic Assumptions 120
Problem I: Nuisance Algae . . . . . 121
Biology of Algae 121
Algae/Techniques with Long-Term Effectiveness '. ,121-
Phosphorus Precipitation and Inactivation . . . . . 121
Sediment Removal .:' 123
Dilution and Flushing . .'126
Algae — Additional Procedures for Control . 127
Artificial Circulation 127
Hypolimnetic Aeration 128
Hypolimnetic Withdrawal . 129
Sediment Oxidation 130
Food Web Manipulation 130
Algicides . . . • • ; • • 133
Algae/Summary of Restoration and Management Techniques 134
Problem H: Excessive Shallowness '.... 135
Problem III: Nuisance Weeds (Macrpphytes), _'. 135
Biology of Macrophytes 135
Macrophytes — Long-Term Control Techniques 136
Sediment Removal and Sediment Tilling ......:. 136
Water Level Drawdown . . 138
Shading and Sediment Covers 139
Biological Controls .'.'...- '.". 141
Macrophytes — Techniques with Shorter-Term Effectiveness . . 144
Harvesting . 144
Herbicides • • • • 147
Macrophytes — Summary of Restoration and Management
Techniques . . .' •;....- ':...... 151
Problem IV: Eutrophic Drinking Water Reservoirs 151
Nature of the Problem 151
Water Supply Reservoir Management ......' ,.152
viii
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'*
Color ;^. .153
Taste and Odor • '. . . . '. . ... 153
Loss of Storage Capacity . . ..". . . ... . ,.....,. ... . . . , . . .153
Trihalomethane Production . . . . .153
Problem V: Fish Management . .154
' Nature of the Problem . . . _f . 154
Diagnosis and Management .154
Problem VI: Acidic Lakes ............... . -155
'-• Limestone Addition to Lake Surface .156
' Injection of Base Materials into Lake Sediment 157
Mechanical Stream Doser . .157
Limestone Addition to Watershed .158
Pumping of Alkaline Groundwater . . . .158
Acidic Lakes — Summary of Restoration and Management
Techniques . . . . . .159
Chapter 7: Hypothetical Case Study
Purpose of Case Study , 161
Lynn Lake—a Case Study .... . . 161
Problem Definition .163
Lake Restoration Advisory Committee ...... .165
Consultant Selection ... 166
Detailed Work Plan . , ..... . . . .... . . . ... . . .167
Phase I Grant Application .168
Lake and Watershed Study .... . . . . - . . . .169
Study of Lake and Watershed Characteristics ; . . . .169
Study of Previous Uses and Recreational Characteristics .169
Lake Monitoring .170
Watershed Monitoring ; ... .172'
Data Analysis .... ... ....................... .174
Lake Analysis .174
Watershed Analysis .• .177
Evaluation of Management Alternatives . . .178
Evaluation Criteria 180'
Effectiveness . , • • • -180
Longevity .180.;
Confidence .181
Applicability . . .181
Potential for Negative Impacts .... . . . .181
Capital Costs ...... ., '......... .;.182
Cost Comparison: Alum Treatment Versus Dredging ....... .182
Watershed Management Alternatives 184
Wastewater Treatment Plant Upgrade 184
Sedimentation Basins 185
Agricultural Practices .185
Construction Controls 185
ix
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In-lake Management Alternatives 187
Public Hearing 190
Selection of Management Plan 190
Chapter 8: Implementing the Management Plan
Management Means Implementation ...:..., . ; 191
Who Does the Work? . . . 191
Selecting Consultants or Contractors 192
Institutional Permits, Fees, And Requirements 193
Implementation Costs Money 194
Plans and Specifications .'..... 194
Funding Sources . 194
Federal Agencies 194 .
State Agencies 196
Local Sources . 196
Implementation Requires Contracts . . 197
Implementation Takes Time '. . . ... .......... 197
Public Education is Critical for Sound Lake Management ........ .198
Postrestoration Monitoring is an Integral Part of Implementation . . . . . .198
Chapter 9:.Lake Protection And Maintenance
Introduction .203
Lake Organizations 203
Regulations In Lake and Watershed Protection And Management .... . .204
Controlled Development . .204
Permits and Ordinances ...'........ 208
Lake Monitoring 209
The Lake Watch 209
References .....:... 211
Appendices
Appendix A: Metric Units . . . . 217
Appendix B: Glossary ..-.. . . . 219
Appendix C: • Point Source Techniques. : .225
Appendix D: Best Management Practices i 231
Appendix E: State/Provincial Lake Management Information 249
Appendix F: Documents and Forms 313
Index . 321
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Chapter 1
OVERVIEW OF MANUAL
Introduction
This Guidance Manual pursues a very broad subject—protecting and restoring
lakes and reservoirs. An enormous amount of information trails behind that topic.
The burden on those who wrote this Manual was not in finding good material to
put in but in deciding where to stop. To make a book so full of information that it
deserves premier shelf space for its reference value but remains compact enough
to lift easily required some guiding assumptions.
First, this Manual supplies its own context. Therefore, any point the reader
finds in midbook is prefaced with adequate background information to understand
it and then followed with guidance on how to apply it. The material presented here
was chosen because it fits a fourfold purpose:
1. To help users identify, describe, and define their lake problems;
2. To help them evaluate available lake and watershed management
practices for addressing problems or protecting current 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. .
Audience
This Manual is written for the informed citizen who is interested in lakes and
reservoirs—in protecting, restoring, and managing them. It is not written for the
scientist or engineer. Consequently, English units of measure are used here, ex-
cept for a few terms that are always reported in metric units. Appendix A provides
the reader with information on the metric system. Many other, more technical
documents discuss specific points of lake and reservoir management in detail.
Additional references and sources of information are given wherever appropriate.
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.
Lake management:
The practice of keeping
lake quality in a state such;
that attainable uses can
be achieved;
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Focus
The focal point of this book is water quality, particularly the effects of excessive
inputs of silt, nutrients, and organic matter known as eutrophication. The reader
will find some information here on the effects of water quality on fish, for example,
but will need another source fo/ detailed advice on fisheries management. State
game and fish agencies, the Fish and Wildlife Service of the U.S. Department of
Interior, the Soil Conservation Service of the U.S. Department of Agriculture, and
other agencies publish numerous booklets, fact sheets, and technical bulletins on
fish management that more than suffice for this omission.
Technical jargon is kept to a minimum to help the reader grasp important
points without stumbling over the words. Even so, a handful of terms are so im-
portant to lake management that working around them would be a disservice.
These terms are defined in a side note the first time they appear, clearly ex-
plained in the text, and included in the glossary. The only term that needs some
advance explanation is the relatively simple word, lake, which is used generically
in this Manual to include both natural lakes and manmade lakes, which are called
reservoirs. Distinctions between the two types of systems are discussed when
they have important management implications.
Lakes as Resources
Lakes are important resources. As sources of recreation, they support fishing,
boating, and swimming. 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, generation of electricity, and sources of drinking water.
Finally, as places of beauty, they offer solitude arid relaxation. This quality is not a
minor asset — over 60 percent of Wisconsin lake property owners who were asked
what they valued in lakes rated aesthetics as especially important.
Natural Lake Conditions
The natural condition of a lake — before home construction, before deforestation,
before agriculture and other human activities — may, not have been nearly as pris-
tine as is commonly believed. The natural geologic process is for lakes of
moderate depth to gradually fill and become wetlands. The position of a lake
along this geologic continuum from deep to shallow influences its natural water
quality. ,
Many lakes would be eutrophic despite development in the watershed and
other human activities. 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 find the,
color of healthy southern lakes dismaying. Even comparing nearby lakes may be
misleading because the lakes may differ in critical ways — depth, water source,
erodibility of watershed soils, comparative watershed size, and local land use.
Major differences can occur from one side of town to the other or across a State.
For example, changes in lake quality from northern to southern Wisconsin or from
eastern to western Minnesota reflect regional differences in these factors.
Regional differences in climate, rainfall, topography (hills, valleys, plains),
soils, geology, and land use all influence lake water quality and land use. These
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lactors have been studied, and used to define areas with similar characteristics
called ecoregions (Omernfk, 1987). Each of these ecoregions has its natural
landscape features that can influence lake quality and should be factored into
lake management Because the natural lake water quality obviously affects uses,
an important goal of both this Manual and lake management is to identify and
define supportable uses and to develop a compatible lake and watershed
management plan to restore the lake to this natural condition or protect its,current
condition. ' (
This Manual provides general guidance on lake restoration and 'management
techniques that have been proven on lakes throughout the United States and
Europe. Different techniques might have to be modified for your particular lake in
a specific region. . .
This variability brings up a key point in lake management: whatever the start-
ing conditions and the limitations on what can ultimately be achieved, the goal is
always the same—to minimize lake quality problems. ,
Desired Lake Uses
Lake usage is a match between people's desires and the lake's capacity to satisfy
these desires. Lake problems are defined in terms of the limits on desired uses—
as limitations that can reasonably be prevented or corrected with proper manage-
ment. 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, these desired uses need to be clear-
ly defined, limitations on the uses identified, and the causes understood.
What a Lake is NOT
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.
Depending on physical characteristics of the lake basin and watershed and
the quality of incoming water, lakes are suited to particular uses. Even when a
lake can be used several ways, however, management for a specific use may still
be required. Like cattlemen and sheepherders, motorboaters and trout fishermen
don't necessarily get along. "
Although it might be technically possible to drastically alter a lake to meet the
needs of a particular user group, the cost will be high, and the decision is usually
unwise. It is important to understand a lake's capacity and attainable quality when
developing a management plan to obtain certain desired uses. Some lakes will
never be crystal clear. No matter what restoration or management measures are
taken, if the drainage area is large relative to lake surface area and the soils,are
highly erodible and nutrient-rich, the lake will promptly return to its former state.
Even the most reliable restoration techniques are not universally appropriate.
The procedure that improves water quality in one lake can diminish it in another.
For example, a technique called artificial circulation can decrease algal problems
in some lakes but may increase algal production i,n others.
.This Manual concentrates on how to determine what uses the lake can sup-
port with reasonable management efforts. It is critical, therefore, to determine the
desired lake uses and have these goals clearly in mind as the problems are
delineated. , ,
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Defining Desired Uses
While user groups obviously are the prime candidates for identifying desirable
goals,- they often lack sufficient knowledge to assess the practicality of their
wishes. The material in this Manual will be helpful in examining the feasibility of
proposed goals. In addition, the advice of experts is highly recommended. Many
State and Federal sources are listed in later chapters of this Manual.
User Involvement
Lake and reservoir management is an active process. Informed citizens must be-
come involved if desired and attainable lake uses are to_be achieved. 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 different groups of
users, several methods might be required to involve them all.
, Lake'homeowners and other local users can get involved with lake use
decisions through membership in one of several types of lake organizations. The
local powers and financial ability of these groups vary considerably from com-
munity to community and State to State. (See Chapter 8 for additional discussion
of legal authority and issues.) Also, 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.
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.
There are several procedures or approaches that can be used to reach a con-
sensus on desired lake uses and to identify various lake problems. These ap-
proaches, described in Appendix 3-A, include the nominal group process and the
Delphi process. While these techniques can be very effective .when properly
used, most lake managers or 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 beginning statement—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 Versus Symptoms—A Major
Reason for This Manual
Lake users tend-to confuse the symptoms of problems with their causes. Most
communities need professional help to identify causes of lake problems. To
decide when professional advice is warranted and how much help is needed,
community leaders need to understand lakes in general. The purpose of this
Manual is to help lake users define problems, understand underlying causes,
evaluate techniques for addressing problems, develop an effective lake manage-
ment 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 environmental engineer. This Manual
provides guidance for finding and selecting qualified consultants.
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Manual Organization
The Manual is divided into three parts.
Part 1—Understanding and Defining the
Problem
• Chapter 2 provides information on how inseparably lakes and watersheds are
coupled and how lakes function as ecosystems. It is important to have some
understanding of how the various components of a lake and watershed work
and fit together. 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 can be accelerated or slowed down by various
management techniques. Chapter 2 describes eutrophication and other
ecological concepts.
• Chapter 3 describes the process used to identify lake problems and differen-
tiate symptoms from causes. This is a critical part of lake management.
Part 2—Management Techniques
• Chapter 4 discusses analytical tools for evaluating the potential effectiveness
of lake and watershed management techniques in achieving a desired lake
use or certain level of lake quality.
• Chapter 5 discusses the effects of watershed land use on lake quality and
various watershed management techniques available to control point and non-
point source pollutants entering the lake.
• Chapter 6 discusses in-lake management techniques for achieving a desired
lake use. It focuses not only on methods but also on their mode of action and
possible interactions with other techniques.
Part 3—Development and Implementation of a
Lake Management Plan
• Chapter 7 describes how the watershed and lake management techniques
are integrated to formulate and develop an effective lake management plan.
The procedure is illustrated by a comprehensive example—a hypothetical
case study. •
• Chapter 8 discusses putting the lake management plan into practice, which
requires attention to numerous practical details such as permits, bonding, in-
surance, and scheduling.
I Chapter 9 discusses how to protect the current lake quality or the lake quality
after restoration. Lake organizations and associations can be effective forces
in protecting lakes. Monitoring the lake status and changes occurring in the
lake is the keystone of lake management and protection. -
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• Appendices and a glossary supplement the material covered in Chapters 1
through 9. As mentioned earlier, this Manual uses English units of measure.
Appendix A shows how to convert English units to metric units, which are more
common units of measure in lake management.
Restoration is not the return of a lake to its original state or some desired state
but rather to the condition in which attainable uses can be achieved. This Manual
explains how to determine the attainable condition of your lake, identify and
prioritize the desired uses that are possible with this attainable lake condition, and
then restore the lake to that condition. Once the lake is restored, it must be
managed if these uses are to be maintained over time. This Manual is intended to
help you determine how to restore, manage, and protect your lake so that you can
enjoy its many benefits.
Definitions
Terms important to the understanding of lake management are defined in the
margins beside their first appearance in the text. (See the definitions of lake
protection, restoration, and management in the margin of the first page of this
chapter.)
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Chapter 2
ECOLOGICAL CONCEPTS
Lake and Reservoir Ecosystems
Lake management must be based on an understanding that lakes are complex
and dynamic ecosystems.
Viewed simply as water systems, lakes are influenced by a set of hydrologic
conditions, the watershed, the shape of the lake basin, the lake water, and the
bottom sediments. These physical and chemical components, in turn, support a
community of organisms that is unique to lake environments (Fig. 2-1). The biota
enrich the complexity of lake ecosystems; they not only have a myriad of links to
one another but also affect a lake's physical and chemical features. All of these
components of lakes—physical, chemical, and biological—are in constant
change, and the chemical and biological components are particularly dynamic.
Because lakes are highly interactive systems, it is impossible to alter one
characteristic, such as the amount of weeds or the clarity of the water, without af-
fecting some other aspect of the system, such as fish production.
For example, a lake association might decide to remove weeds by mechanical
means, and, in the process, accidentally destroy important habitat needed for fish
survival and increase proliferation of algae, which would feed on nutrients inad-
vertently released during the weed harvesting. If the lake association then
decided on chemical treatment to solve the algae problem and help clear up the
water, the next step in this sequence of events could be increased penetration of
sunlight through the water, which would encourage new weed growth.
Ecology is the scientific study of the interrelationships among organisms and
their environment.. Managing a lake for maximum benefit requires an under-
standing of how.its ecosystems are structured and how they function. This lake
management example is hypothetical, but variations on such unexpected results
occur repeatedly when programs are implemented without adequate knowledge
of lake ecology. It also illustrates a common confusion between causes and
symptoms. Not only did the lake association members fail to consider how lake
organisms interacted with one another, they also did not determine why weeds
and algae were growing profusely and whether this aquatic plant production
'should be viewed as a problem or an asset. '
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 plant and animal
species 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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Marginal zone
Littoral zone
Pelagic zone
Profundal zone
Pelagic zone (open water)
. Benthic zone
Figure 2-1.—The location and nature of typical lake communities,, habitats, and organisms. In
addition to the lake's watershed, all of these components are part of the lake ecosystem.
8
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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, arid streams. An understanding of limnol-
ogy is the backbone of sound lake management. •
This chapter is not intended to be a text on either aquatic ecology or limnology.
Rather, its goal is to provide the background information necessary to understand
the causes of lake degradation problems and to identify the most applicable lake
management and restoration approaches.
The Lake and Its Watershed
Water, dissolved materials carried in water, and particulates, such as soil, enter
the lake from its waters'hed.
Lakes are constantly receiving these materials from watersheds, acid
precipitation and dust from the atmosphere, and energy from the sun and wind.
Therefore, water quality and productivity are as much influenced by what can
(and will) go into the lake as by what is already there. Important factors include
watershed topography, local geology, soil fertility and erodibility, vegetation in the
watershed! and other surface water sources such as runoff and tributary streams.
See the boxed section and Figure 2-A on the hydrologic cycle/which describes
major natural phenomena controlling water supply availability. ' :
Water
The amount of water entering the lake from its watershed controls volume and
several other factors that influence the lake's overall health. A lake, like any water
tank, takes a predictable amount of time to fill and to empty, given a certain rate of
flow. Unlike rivers, lakes essentially slow the flow of water; thus, any water enter-
ing the lake will remain in it for a period called the hydraulic residence time (see
boxed section and Fig. 2-B). Water quality reflects the history of the lake water, as
well as the condition of new incoming water.
Because of hydraulic residence time, management programs directed at im-
proving incoming water and, therefore, lake water quality, will face a lag period
between the time that incoming water quality gets better and the time that change
becomes evident in the lake. The longer the hydraulic residence time, the greater
the lag.
Since water affects and is affected by the biota, sediments, and existing water
chemistry, additional delays between changes in the quality of incoming water
and that of intake water may also occur.
Dissolved Materials
One of the most important materials dissolved in water is oxygen. Sources of dis-
solved oxygen include inflowing water, transfer from the atmosphere (gas ex-
change), and photosynthetic production by aquatic plants.
Oxygen production by plants is discussed later in this chapter. Oxygen is con-
sumed or removed from the lake by outflow, loss to the atmosphere, nonbiologi-
cal combination with chemicals in the water and mud (chemical oxygen demand
or COD), or plant, bacterial, and animal respiration. Biochemical oxygen demand
(BOD), which is a common measure used to describe the rate of oxygen con-
sumption by organisms and materials under dark conditions, varies with the
amount of organic matter and bacteria in the water. Municipal wastewater dis-
charges have very high BOD, for example!
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.
Watershed: A drainage
area or basin in which alt
land and water areas •
drain or flow toward a
central collector such as
a stream, river, or lake at
a lower elevation.
Chemical oxygen
demand (COD):
Nonbiological uptake of
molecular oxygen by
organic and inorganic
compounds in water.
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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
evaporation 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 underwater seeps, springs, or surface channels and then
evaporates into the atmosphere.
SEEP
INFILTRATION
GROUND WATER
WATER TABLE
Figure 2-A.—Hydrologic cycle.
Lakes and reservoirs have a water "balance," as described in this simple equation:
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 out-
puts, lake levels rise as water is stored. Conversely, when outputs are greater—for
example, during a summer drought—lake levels fall as losses exceed gains.
Some lakes, called seepage lakes, form where the groundwater flow system inter-
sects with the land surface. Seepage lakes are maintained primarily by
groundwater 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 watersheds. 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.
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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 bairn.
tub with the tap fully open and the bottom drain closed. The hydraulic residence 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 acre-ft/day
Lake volume =,
500 acre-ft
Water residence time = 500 acre-ft * 10 acre-ft/day = 50 days
•" \ .
Figure 2-B.—Hydraulic residence time Is an Important factor to consider In restora-
tion programs. The simple formula given In the figure assumes that Inflow Is equal
to outflow. f
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 accumulate.
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 accumulate:
Longer water residence times from 100 days to several years provide plenty of time
for algal biomass to accumulate if there are sufficient nutrients present. The production
of algae may ultimately be limited by the supply of nutrients. If the nutrient supply 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 algae 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 methods are
discussed in Chapter 4. • - . . •
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When the loss of oxygen from the water exceeds the input of oxygen from
various sources, the oxygen content of the lake water is decreased. If the dis-.
solved oxygen becomes severely depleted, anoxic conditions can occur that lead
to odors, fishkills, increased phosphorus and ammonia concentrations, and other
undesirable effects.
Inflowing stream water also carries the two principal plant.nutrients—nitrogen
and phosphorus—in both dissolved organic and inorganic forms. Nitrogen and
phosphorus are required for the biological production of phytoplankton (free-float-
ing microscopic algae) and macrophytes (larger floating and rooted plants). (See
Organic Matter Production and Consumption in this chapter.)
Surface and subsurface drainage from fertile (nutrient-rich) watersheds results,
in biologically productive lakes, and drainage from infertile (nutrient-poor) water-
sheds results in biologically unproductive lakes. The relative fertility of water-
sheds and, thus, of lakes varies locally and regionally, as is discussed in the
boxed section on regional differences in lake water quality and biological produc-
tivity. ' .
Soils, weathered minerals, and decomposing organic matter in the watershed
are the main natural sources of phosphorus and nitrogen. However, manmade
sources such as agriculture, crop and forest fertilizers, and wastewater dis-
charges commonly increase the rate of nutrient income or. loading from water-
sheds and are the major causes of biological overproduction in many lakes (Table
2-1). Watershed disturbances such as logging and mining, which remove natural
vegetation, can greatly increase .the amount of silt and nutrients exported from
the land to the lake (see Chapter 5). Finally, pesticides, herbicides, toxic pol-
lutants, chemicals in wastewater discharges, and industrial waste materials may
also enter the lake with incoming water.
Table 2-1.—Representative values for nutrient export rates and input rates for
various land uses. All values are medians and are only approxima-
tions owing to the highly variable nature of data on these rates.
LAND USE TOTAL PHOSPHORUS TOTAL NITROGEN
A. Export rates (kg/ha/yr)1-2
Forest . 0.2 2.5.
Nonrow crops . 0.7. , 6.0
Pasture 0.8 14.5
Mixed agriculture 1.1 • .5.0,
Row crops 2.2 9.0
Feedlot, manure storage • 255.0 . 2920.0
B. Total atmospheric input rates (kg/ha/yr)1-3
Forest ' ' '• 0.26 ' . .6.5
Agricultural/rural . 0.28 13.1
Urban industrial . 1.01 . 21.4
C. Wastewater input rates (kg/capita/yr)4 •
Septic tank input5 , 1.45 4.65
1 Values in this table are all in kg ha yr, which is the standard for such measurements.-To convert to pounds per acre per year.
multiply by 0.892. '.'._.
3 Source! Reckhow et al. 1S80. Figure 3, •
3 Source: Reckhow et al. 1980. Table 13. • .
4 Source: Reckhow et al. 1980. Table 14.
* This is prior to absorption to soil during infiltration; generally, soils will absorb 80 percent or more ol this phosphorus
12
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Regional Differences in Lake Water
Quality, Productivity, and Suitability
15 ' -
Lake water quality and productivity are influenced directly by the nature of the lake
watershed; that is, by the watershed topography, soil fertility and credibility, vegetation,
and hydrology. Similarly, but on a larger scale, the character of lakes located in regional
drainage systems are broadly influenced by the regional geology, topography, hydrol-
ogy, soils, and vegetative cover. Both the lake watershed and regional conditions exert
natural controls on lake trophic status, water quality, and biological productivity. Forex-
ample, a deep alpine lake located in a granitic watershed in the Colorado Rockies is al-
most certain to have pristine, crystal clear, high quality water but very low biological
productivity and poor fishing. On the other hand, a turbid reservoir in southern Missis-
sippi or Alabama may be considered to have poor water quality because of its high tur-
bidity; high concentrations of nutrients and organic matter, and frequent occurrences of
algal blooms; however, this impoundment will likely support a productive sport fishery
and be highly valued for its trophy bass. ,
North American lakes have extremely variable water quality, biological produc-
tivity, and fish community structure. This variability is due in large part to regional dif-
ferences in the nature of lake watersheds and to a tremendous local diversity in lake
morphometry (i.e., shape, depth, volume, surface area). Studies of the relationship be-
tween lake morphometry, water chemistry, and fish yield have generally shown that
nutrient-rich, shallower lakes are typically more biologically productive and have
higher fish yields per unit area than deeper, less fertile lakes. Along a water quality or
trophic-status, continuum ranging from oligotrophic (nutrient-poor, biologically un-
productive, good water quality) through eutrophic (nutrient-rich, productive, poor
water quality) lake conditions, there is also, a continuum of fishery yield and fish com-
munity structure. .. . :.-...
• Generally, the better the lake water quality, the poorer the fishery yield (and vice
versa) and, depending on the desired uses of a particular lake, there is often potential
conflict between fishery optimization and water quality-related lake management ob-
jectives. Necessarily, maximum fishery yield results from high biological productivity
and high plankton biomass (Jones and Hoyer, 1982; Wagner and Oglesby, 1984), while
high water quality, high water transparency, low treatment costs; and the greatest aes-
thetic appeal are usually associated with low plankton biomass (Fig. 2-C). Conse-
quently, without clearly established lake management priorities, maximized (or even
improved) fish production may be incompatible with water quality-related lake
management objectives. WATER QUALITY
FISHERY YIELD
TTin i i i nun i i mini i i i inn
Figure 2-C.—Relationship
between lake characteristics
(e.g., water clarity, algal
biomass) and management
objectives (e.g., water quality,
fishery yield). Modified from
Wagner and Oglesby (1984).
1 •
0.1
i i i mm
1 ,10 100
MEAN SUMMER CHLOROPHYLL a <
1000
Given the strong natural controls that the regional setting and the nature of the
watershed exert on lake conditions, it is clear that particular lakes are best suited for
particular uses. To be most effective, lake managers must first identify those uses that a
lake can best support and then develop a compatible lake and watershed management
plan to take advantage of the lake's natural condition.
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Organic matter:
Molecules manufactured
by plants and animals and
containing linked carbon
atoms and elements such
as hydrogen, oxygen,
nitrogen, sulfur, and
phosphorus.
Sediment: Bottom
material in a lake that has
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).
Littoral zone: That
portion of a waterbody
extending from the
shoreline lakeward to the
greatest depth occupied by
rooted plants.
Pelagic zone: This is the
open area of a lake, from
the edge of the littoral zone
to the center of the lake.
Particulates
Organic matter, clays, and silt particles wash from the watershed into the lake.
Where the land is disturbed, the soil loss is apt to be high. Even removing brush
and replacing it with a poor stand of lawn can increase the rate of erosion. Al-
though erodibility among soil types varies, it is one factor that must be considered
in watershed management programs.
In1 addition to soil loss from the land through rainfall, and snowmelt, streams
may scour soil from their banks. Wind also carries some particulates, such as
dust and pollen, directly to lakes. Inputs of suspended particles result in in-
creased turbidity, which decreases water transparency and light availability and
reduces plant growth.
Lakes are extremely efficient sediment traps. Filling in with silt is part of a
lake's natural aging pattern, but poor land management practices can speed up
the process significantly. Suspended sediment particles that can be easily carried
by rivers and streams settle out once they reach the relatively quiescent lake en-
vironment. As a consequence, particle-associated nutrients, organic matter, and
toxic contaminants are often retained in lake sediments, and the influx of her-
bicides, pesticides, and toxics adhered to soil particles is becoming an increas-
ingly common problem for lakes.
Incoming silt is another problem. Silt-laden water can reduce penetration of
sunlight and, consequently, the light available to algae. Many species of fish are
sight feeders; they cannot locate prey efficiently in muddy waters. Silt deposits
' can also prevent successful hatching of fish eggs that require clean surfaces.
Finally, excessive levels of silt can irritate the gills of fish, causing respiratory dif-
ficulties and poor health. . .
The Sedimentation and Decomposition section in this chapter discusses
how organic matter in the water, affects dissolved oxygen. Particles of organic
matter can enter the lake suspended in tributary streams or can originate from
aquatic plants and animals within the lake Itself. Controlling soil loss from the
watershed is treated in Chapter 5 in the discussion of best management prac-
tices. The use of dredging to deepen a lake and remove sediments is discussed
in Chapter 6.
Effects of Lake Depth
Shallow lakes tend to be more biologically productive than deep lakes because of
the large area of bottom sediments relative to the volume of water, more complete
wind mixing of the lake water, and the large, very shallow (littoral) areas along the
lake perimeter that can be colonized by rooted and floating macrophytes. Indeed,
shallow lakes may be dominated by plant production,in littoral areas and have lit-
tle open water habitat. Large inputs of silt and incomplete decomposition of mac-
•rophytes can make lakes become shallow rapidly and, usually, shallow lakes
have a shorter hydraulic residence time.
Deep, steep-sided lakes usually stratify thermally during the summer, which
prevents complete mixing of the lake water. These lakes may have fewer areas
that are shallow enough for rooted aquatic plants to receive light and grow. Thus,
deep lakes generally have a high proportion of open water (pelagic) habitat, and
their food webs tend to be based on the organic matter produced by planktonic
algae or phytoplankton. Many reservoirs have large areas of shallow water, but
flood control operations often cause water level fluctuations that discourage well-
developed stands of aquatic weeds along the shoreline. .
14
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Manmade Lakes
In contrast to the glacial lakes that may be thousands of years old, most man-
made impoundments have been constructed within the past 100 years. Ponds,
Stock tanks, and small reservoirs have been formed for agricultural use, municipal
water supply, soil and water conservation, sport fishing, and recreation. Large
reservoirs are usually constructed by Federal agencies by impounding major
rivers and are operated for multiple purposes that include water supply, flood con-
trol, and hydroelectric power generation.
The purpose and location of "an impoundment usually determine its basin size,
and the topography of the inundated valley dictates the basin shape. The "geol-
ogy, soil type, and vegetation in the valley and the watershed directly affect reser-
voir productivity and water quality. Because reservoirs are often flooded river val-
leys, many of these manmade lakes are long and narrow rather than circular or
ovoid like many natural lakes, and they tend to have irregular shorelines (Fig. 2-
2). Additionally, while natural lakes tend to have diffuse sources of inflowing
water, relatively low watershed areas compared to lake surface area, and long
Natural Lakes
• Smaller watershed area
• Longer hydraulic residence time
'-•'• Simpler shape, shoreline
• Surface outlet
Watetshed boundary
Reservoirs ~—- —-,--
• Larger drainage area "
• Shorter hydraulic residence time
• More complex shape, shoreline .
• May have surface and/or subsurface outlet(s).
Figure 2-2.—General comparison of reservoirs to natural lakes.
15
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hydraulic residence times, reservoirs usually differ in all of these traits, and these
differences account for the great variety in water quality and productivity that can
occur between and among lakes and reservoirs.
Typically,.a reservoir has one or two major tributaries, a very large watershed
compared to lake surface, and relatively short hydraulic residence times. The in-
puts of dissolved and particulate organic and inorganic materials from the water-
shed are also likely to be very'high. Of course, the most distinctive difference be-
tween natural lakes and reservoirs is the subsurface outlet commonly possessed
by large reservoirs with dams designed for hydroelectric power generation.
Actually, there are probably more similarities than differences between natural
lakes and reservoirs. The physical, chemical, and biological conditions in both
overlap greatly, as illustrated in Figure 2-3. With regard to the environmental fac-
tors that control water quality and biological productivity, reservoirs occupy an in-
termediate position between natural lakes and rivers on a conceptualized con-
tinuum of aquatic environments (Kimmel and Groeger, 1984). Hydraulic
residence, time is the characteristic that most influences the relative productivity
and water quality of natural lakes and reservoirs (Soballe and Kimmel, 1987),
RIVERS
LAKES
RESERVOIR'S |—
MAIN STEM
'RUN-OF-THE-RIVER"
RESERVOIRS
MAIN STEM
STORAGE
RESERVOIRS
TRIBUTARY
STORAGE
RESERVOIRS
INCREASING HYDRAULIC RESIDENCE TIME
Figure 2-3.—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 determining the rela-
tive positions of different types of reservoirs.(malnstem-run-of-the-rlver, malnstem storage,
and tributary storage Impoundments) along the river-lake continuum. Modified from Kimmel
and Groeger (1984). >
Lake Processes
Lake Stratification and Mixing
In spring and early summer, the combination of solar heating and wind mixing of
near-surface water layers brings about the .warming of the upper portion of the
lake water column and the stratification of many lakes and reservoirs into layers
of water with different temperatures and densities (Fig. 2-4). Rapidly flushed,
shallow lakes that are exposed to strong winds, however, do not normally develop
persistent thermal stratification. Refer to the boxed section on the unique proper-
ties of water for a discussion of the water temperature-density relationship that
results in the thermal stratification of lakes.
16
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*
EPILIMNION OR MIXED LAYER—WARM (LIGHT) WATER £>
DEGREES FARENHEIT
4
E
DISSOLVED OXYGEN Img/U
Figure 2-4.—A cross-sectional view of a thermally stratified lake in mid-summer. The water
temperature profile (curved solid line) illustrates how rapidly the water temperature decreases
in the metalimnion compared to the nearly' uniform temperatures in the epifimnion and
hypolimnion. The metalimnetic density gradient associated with this region of rapid tempera-
ture change provides a strong, effective barrier to water column mixing during the summer
months. Open circles represent the dissolved oxygen (DO) profile in an unproductive
(oligotrophic) lake: the DO concentration increases slightly in the hypolimnion because
oxygen solubility is greater in colder water. Solid circles represent the DO profile in a produc-
tive (eutrophic) lake in which the rate of organic matter decomposition is sufficient to deplete.
the DO content of the hypolimnion.
During summertime thermal stratification, a warmer, less dense layer of water
(the epilimnion) floats on a cooler, denser water layer (the hypolimnion). These
two layers are separated by a zone of rapidly changing temperature and density
called the metalimnion. The term "metalimnion" is often used loosely, but the clas-
sical definition is the stratum of water of rapid thermal change with depth, above
and below which are zones of uniformly warm (epilimnion) and cold (hypolimnion)
water layers. The thermocline, defined as a horizontal plane of water across the
lake through the point of the greatest temperature change,, is within the metalim-
nion. .' • •
Mixing Processes
The most important lake mixing mechanisms are wind, inflowing water, and out-
flowing water. Wind affects the surface waters of all lakes, but the effectiveness of
wind in mixing the entire water column is sharply curtailed in some lakes during
the.summer. During summertime thermal stratification, a lake usually cannot be
completely mixed by wind. When the lake water cools in the fall, the temperature-
controlled zonation breaks down and the water column mixes completely.
Epilimnion: Uppermost,
warmest, well-mixed layer .
of a lake during
summertime thermal
stratification. The epilimnion
extends from the surface to
the thermocline.
Hypolimnion: Lower,
cooler layer of a lake during
summertime thermal
stratification.
17
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* 7/ie 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
not as light as 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 under-
stand water's physical and chemical properties. The molecular structure of water 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 dis-
solve readily in it.
2. Water is a liquid at natural environmental temperatures and pressures. Although
this property seems rather common and obvious, in fact, it is quite important. If
water behaved at ordinary temperatures and pressures as do chemically similar in-
organic 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
increasingly dense (more mass, or weight, per unit volume) as they cool. Water
also rapidly becomes more dense as its temperature drops, but only to a certain
point (Fig. 2-D). 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 dif-
fering 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 water density that accompany rapid-
ly 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 cojumn mixing.
TEMPERATURE AND THE DENSITY OF WATER
5 10 15 20 25 30 °C .
"" ' ' ' ' ' TEMPERATURE °C
0 5 10 15 20 25 30
t&A3=>z&z&&3si&&&&tt
i EPILIMNION 20-25°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
'METALIMNION 15-20°C:
;:HYPOLIMNION 4-15°C:
-5
1.00000
0.99900
0.99800
0.99700
0.99600
0.99500
0.92
0.91
•LIQUID TO ICE
Figure 2-D.—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 ener-
gy required 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 ex-
ample is the Great Lakes, which have a dramatic effect on both the air temperature
and on the precipitation in the States and Provinces surrounding them.
18
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In stratified lakes, the thickness of the epilimnion is considered to be the depth
to which water is consistently mixed by wind. How deep (or thick) this layer be-
comes during the summer depends upon how resistant the water column is to
mixing. The greater the temperature difference between the epilimnion and the
hypolimnion, the more wind energy is required to mix the water column complete-
ly to the bottom of the lake..The density gradient (change in density) of the
metalimnion acts as a physical barrier to the complete mixing of the epilimnion
and hypolimnion. '
In the spring, just after thermal stratification is established, the hypolimnion is
rich in dissolved oxygen from early spring mixing of the water column and plant
oxygen production. However, because of the barrier properties of the ther-
mocline, the hypolimnion is isolated from gas exchanges with the atmosphere
during the summer and is often too dark for photosynthetic production of oxygen
by green plants^ In a productive lake, the hypolimnion can become oxygen-
depleted during the period of summer thermal stratification as its reserve of dis-
solved oxygen is consumed by the decomposition (respiration) of organic matter.
This event has very important consequences for lake productivity and fishery
management and is one of the major targets of lake restoration activities. Most
fish require relatively high dissolved oxygen levels and cannot survive in an
oxygen-deficient hypolimnion; however, the epilimnion may be too warm for their
survival. Additionally, under anoxic conditions, nutrients such as nitrogen and
phosphorus, are released from the bottom sediments to the water column, where
they ultimately promote additional algal production organic matter decomposition,
and more severe hypolimnetic oxygen depletion.
As the epilimnion cools in the late summer and fall, the temperature difference
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. 2-5). This'destratification process
is often referred to as the fall overturn.
(A.) SUMMERTIME THERMAL STRATIFICATION
EPILIMNION
THERMOCLINE
METALIMNION
HYPOLIMNION '
(B.) ANNUAL CYCLE OF THERMAL STRATIFICATION
Figure 2-5.—Seasonal patterns In the thermal stratification of North Temperate Zone lakes and
reservoirs: (A) summertime stratification; (B) the annual cycle of lake thermal stratification.
Decomposition: The
transformation of organic
molecules (e.g., sugar) to
inorganic molecules
(e.g., carbon dioxide and
water) through biological
and nonbiological
processes.
19
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Water Movements
The wind-driven vertical mixing of the water column, just discussed, is only one of
several types of water movements in lakes. .
The downstream flow of water usually controls the transport of dissolved and
suspended particles, particularly in river-like lakes and in many large, manmade
impoundments dominated by major tributaries. Many natural lakes, however,
have numerous, diffuse inflows (including subsurface inflows) and a surface out-
let. In such lakes, the downstream flow of water from the watershed is not a major
influence on lake water movements. Commonly, however, large reservoirs have
deep subsurface (often hypolimnetic) outlets from the dam that tend to promote
subsurface density flows (Fig. 2-6). A density flow occurs when inflowing water is
cooler and thus denser than the epilimnetic water and, therefore, sinks or plunges
to a depth of equivalent water temperature or density before continuing its
downlake flow.
INTERFLOW v OUTFLOW
Figure 2-6.—Types of density flows In reservoirs. Often the Inflowing river water and the reser-
voir water differ In temperature, and therefore, In the density. If the river Inflow Is warmer than
the reservoir, the less dense river water will spread over the reservoir surface as an overflow
(upper panel). 'If the river Inflow Is of an Intermediate temperature and density, It will plunge
from the surface and proceed downstream as an Interflow at the depth at which the river water
and reservoir water densities are equal (middle panel). If the river Inflow Is cooler and denser
than the entire reservoir water mass, the Inflowing river water will plunge from the surface and
flow along the reservoir bottom as an underflow (lower panel).-Modified from Wunderllch
(1971).
20
-------
Under stratified conditions, these density flows may pass through an entire
reservoir along the bottonvor at an intermediate depth without contributing sig-
nificant amounts of nutrients or oxygen to the upper mixed layer. This is a com-
mon' phenomenon in series of deep-discharge impoundments. .Cold water
released from an upstream reservoir may traverse the next reservoir in the series
as a discrete subsurface flow. This short-circuiting underflow may even be per-
ceived as desirable for water quality because it allows nutrient-laden water to flow
through the reservoir without contributing to nuisance levels of algal production.
Fishermen, however, may view this short circuit with less enthusiasm because a
reduction in algal production may be detrimental to overall lake production offish.
Organic Matter Production and
Consumption
Photosynthesis and Respiration
Planktonic algae (phytoplankton) and macrophytes use the energy from sunlight,
carbon dioxide, and water to produce sugar; water, and molecular oxygen (Fig. 2-
7). The sun's energy is stored in the sugar as chemical bond energy. The green
pigment, chlorophyll, Js generally required for plants to do this. Sugar, along with
certain inorganic elements such as phosphorus, nitrogen, and sulfur, is then con-
verted by plant cells into organic compounds such as proteins 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 and analogous to the standing crop or biomass of plants in a
farmer's' field. While in-lake photosynthesis normally is the dominant source of or-
CO2 + H2O + NUTRIENTS + SUNLIGHT
PHOTOSYNTHESIS
RESPIRATION &
DECOMPOSITION
(CH2O) + H2O + O2
Figure 2-7.—The equilibrium relationship between photosynthesis and respiration-decom-
position processes. The photosynthetic conversion of light energy, carbon dioxide (COj),
water (tfoO), and nutrients Into organic matter produces oxygen (Oz) and results In nonequl-
llbrium concentrations of carbon, nitrogen, sulfur, and phosphorus In organic compounds of
high potential energy. Resplratton-decompostion processes tend to restore the equilibrium by
consuming oxygen and decomposing organic materials to Inorganic compounds.
Density flows: A flow of
water of one density
(determined by
temperature or salinity)
over or under water of
another density (e.g., flow
of cold river water under
warm reservoir surface
water).
Macrophytes: Rooted
and floating aquatic plants,
commonly referred to as
waterweeds. These plants
may flower and bear seed.
Some forms, such as
duckweed and coontail
(Ceratophyllum), are
free-floating forms without
roots in the sediment.
21
-------
Primary productivity:
The rate at which algae
and macrophytesfix or
convert light, water, and
carbon dioxide to sugar in
plant cells. Commonly
measures as milligrams of
carbon per square meter
per hour.
Phytoplankton:
Microscopic algae and
microbes that float freely
in open water of lakes and
oceans.
ganic matter for the lake's food web, most lakes also receive significant inputs of
energy in the forms of dissolved and particulate organic matter from their water-
sheds.
In the process of photosynthesis, molecular oxygen is produced as well, and
this is the primary source of dissolved oxygen, in the water and of oxygen in the
atmosphere. Oxygen is usually required to completely break down organic
molecules arid release their chemical energy. 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. 2-7).
Because of the requirement for light, the primary (photosynthetic) production
of organic matter by aquatic plants is restricted to the portion of the lake water
column that is lighted (also called the photic zone). The thickness of the photic
zone depends upon the transparency of the lake water and corresponds to the
depth to which at least. 1 percent of the surface light intensity penetrates. Below
this, in the aphotic zone, the available light is too weak to support a significant
amount of photosynthetic production.
Phytoplankton production is controlled primarily by water temperature, light
availability, nutrient availability, hydraulic residence time, and plant consumption
by animals. Macrophyte production is controlled more by temperature, light, and
bottom soil types. Most rooted macrophytes obtain their nutrients from the bottom
sediments rather than the water and are restricted by light penetration to the shal-
low littoral water. ,
When light is adequate for photosynthesis, the availability of nutrients often
controls phytoplankton productivity. In the lake, differences between plant re-
quirements for an element and its availability exert the most significant limit on
lake productivity. Table 2-2 compares the relative supply of essential nutrients to
their demand for plant growth. Phosphorus and nitrogen are the least available
elements, and therefore they are the most likely to limit lake productivity.
Table 2-2.—The listed elements are required for plant growth. Plant demand is
represented by the percentage of these essential elements in the liv-
ing tissue of freshwater plants. Supply is represented by the propor-
tions of these elements in world mean river water. The imbalance
between demand and supply is an important factor in limiting plant
growth (after Vallentyne, 1974).
ELEMENT
Oxygen
Hydrogen
Carbon
Silicon
NITROGEN
Calcium
Potassium
PHOSPHORUS
Magnesium
Sulfur
Chlorine
Sodium
Iron
SYMBOL
o
H
C
Si
N
Ca
K
P
Mg
S
Cl
Na
Fe
DEMAND BY
PLANTS (%)
80.5
9.7
6.5
1.3
.7
.4
.3
.08
.07
.06
.06
.04
.02
SUPPLY IN DEMAND: SUPPLY
WATER (%) RATIO1
89
11
.0012
.00065
.000023
,0015
.00023
.000001
.0004
.0004
.0008
.0006
.00007
1
1
5,000
2,000
30,000
< 1,000
1,300
80,000
< 1,000
<1 ,000
< 1,000
< 1,000
> < 1,000
1 Percent of element in plant tissue • • percent in available water. The higher the ratio, the more scarce 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.
22
-------
Phosphorus in particular can often severely limit the biological productivity
of a lake. The by-products of modern society, however, are rich sources of this
element. Wastewaters; fertilizers, agricultural drainage, detergents, and
municipal sewage contain high concentrations of phosphorus, and if allowed to
enter the lake, they can stimulate algal productivity. Such high productivity,
however, may result in nuisance algal blooms, noxious tastes and odors,
oxygen depletion in the water column, and undesirable fishkills during winter
and summer.
Since phosphorus is most often the nutrient that limits algal productivity, it is
usually the element that is the focus of many lake management or restoration
efforts aimed at reducing algal production and improving lake water quality.
Phosphorus loading can be reduced, for example, by chemical flocculation in
advanced wastewater treatment plants or controlled in the watershed by using
proper agricultural and land management practices, improving septic systems,
and applying fertilizer carefully (see Chapter 5).
In the past 20 years, there have been increasing efforts to minimize phos-
phorus inputs to lakes as a way to curb eutrophication. Methods for precipitat-
ing or inactivating phosphorus within the lake are discussed in Chapter 6 under
Algae/Techniques With Long-Term Effectiveness. A method for determining the
amount of phosphorus coming from the watershed is discussed in Chapter 3,
and a formula for calculating the amount is given in Chapter 4. In contrast,
however, poor fishing may be considered the problem of highest priority for in-
fertile Jakes in some regions and improving the fishery yield may be the
primary lake management objective. In such cases, additions of phosphorus-
and nitrogen-containing fertilizers may be used as a lake management tool to
increase phytoplankton production, plankton standing crop, and ultimately, to
enhance fish production.
Phytoplankton Community Succession
As the growing season proceeds, a succession of algal communities typically
occurs in a lake (Fig. 2-8). Phytoplankton biomass usually tends to be high in
the spring and early summer by virtue of increasing water temperature and
light availability, relatively high nutrient availability, and low losses to
zooplankton grazing (consumption by microscopic animals). As grazing pres-
sure increases and nutrient availability declines'from early to midsummer, algal
biomass declines. It rises again in the late summer and fall when water column
mixing increases the supply of nutrients and other conditions provide a
favorable environment for the growth of algae. Sometimes, particularly in very
productive lakes, blue-green algae form floating scums on the surface of the
lake. Algal production and biomass are usually low in the winter because of low
water temperatures and low light availability.
Sedimentation and Decomposition
Sedimentation occurs when particles (silt, algae, animal feces, and dead or-
ganisms) sink through the lake water column onto the lake bottom. Sedimenta-
tion is a very important process that affects phytoplankton biomass levels,
phytoplankton community succession, and transfers of organic matter,
nutrients, and particle-associated contaminants from the lake's upper layers to
the bottom sediments. One reason for the dominance of blue-green algae in
some lakes is their ability to regulate their buoyancy and, therefore, to counter
sedimentation. Sedimentation of particulate organic matter from the water
column to the lake bottom provides a critical linkage between planktonic
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.
Zooplankton:
Microscopic animals that
float freely in lake water,
graze on detritus
particles, bacteria, and
algae, and may be
consumed by fish.
23
-------
Trophic state: The
degree of eutrophication
of a lake. Transparency,
chlorophyll a levels,
phosphorus
concentrations, amount
ofrnacrophytes, and
quantity of dissolved
oxygen in the
hypolimnion can be
used to assess trophic
state.
Figure 2-8.—A typical seasonal succession of lake phytoplankton communities. Diatoms
dominate the phytoplankton In the spring and the autumn, green algae in midsummer, and
blue-green algae (cyanobactpria) in late summer;
primary production and the growth of bottom-dwelling organisms (such as
aquatic insect larvae, clams, and crayfish) that eat this detrital organic matter
and, in turn, are eaten by larger predatory organisms, such as fish and turtles.'
Settling plankton, zooplankton feces, and other organic detritus particles
are degraded in the water column and in the bottom sediments through
oxygen-consuming decomposition processes. Organic matter decomposition,
a collective term for the net conversion of organic material back to inorganic
compounds (see Fig. 2-7), occurs through the respiratory activities of all or-
ganisms, including bacteria, fungi, and other microbes.
In the hypolimnion of productive lakes, the sedimentation of organic matter
from the surface waters is extensive. And because algae and other suspended
particles are abundant, light penetration through the water column to the
hypolimnion is limited or absent and photosynthesis cannot occur. Under these
conditions, the oxygen consumed in the hypolimnion and bottom sediments
during the decomposition (respiration) of this organic matter greatly exceeds
the oxygen produced.. Also, as described earlier, the hypolimnion is isolated
from the atmosphere by a temperature or water density barrier to mixing known
as the metalimnion. The result, in productive thermally stratified lakes, is a
depletion and sometimes a complete absence of dissolved oxygen in the
hypolimnion (see Fig. 2-4). A similar result can occur, though more slowly, in
shallow, productive lakes with a prolonged snow and ice cover.
The chemical and physical changes associated with oxygen depletion are.
marked. They include increased nutrient release from the bottom sediments,
destruction of oxygenated habitats for aquatic animals, and incomplete decom-
position of sedimented organic matter (Fig. 2-9). These symptoms are often
characteristic of lake trophic status (see description of trophic status in Lake
Aging and Cultural Eutrophication in this chapter).
• Oligotrophic lakes: Insufficient organic matter is produced in the epilim-
nion to reduce hypolimnetic oxygen concentrations significantly; the hypolim-
nion remains relativelyoxygenated throughout the year.
24
-------
Plant nutrient uptake, photosynthesis of
organic matter and dissolved oxygen.
*•«• - THERMOCLINE
Consumption of dissolved oxygen In
respiration-decomposition processes, nutrient
regeneration by organic matter decomposition.
Accumulation of nutrients and organic
sediments, release of dissolved nutrients from
sediments to water.
Figure 2-9.—Influence of photosynthesis and respiration-decomposition processes and or-
ganic matter sedimentation on the distribution of nutrients, organic matter, and dissolved
oxygen In a. stratified lake.
• Eiitrophic lakes: Organic matter decomposition can rapidly exhaust the
dissolved oxygen in unlighted zones, leading to anoxia in the hypolimnion.
During midsummer, when a temperature-oxygen squeeze can develop in
stratified lakes, cool water fish such as trout cannot occupy the oxygen-
depleted lower waters and must stay in less than ideal warmer upper waters.
In anoxic conditions, metals such as iron, manganese, and sulfur and the
nutrients phosphorus and ammonium'(a nitrogen compound) become increas-
ingly soluble and are released from the sediments into the hypolimnion. Sum-
mer partial mixing events, which can occur during the passage of summer cold
fronts with wind and cold rains, can transport some of these released nutrients
to the lake surface where they may stimulate more algal production. At fall
turnover, these metals and nutrients reenter the photic zone and may also
stimulate algal blooms. Nutrients that reenter the water column from sediments
constitute an "internal nutrient load" to the lake. Lake managers must be aware
of this internal source of nutrients in addition to the nutrients entering from the
watershed.
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 waterbodies .{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 main-
tain productive food webs (Adams et al. 1983).
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.
Nutrient Cycling: The
flow of nutrients from
one component of an
ecosystem to another,
as when macrophytes
die and release
nutrients that became
available to algae
(organic to inorganic
phase and return).
25
-------
Producers:
Green plants that
manufacture their
own food through
photosynthesis.
Some of the- organic matter produced photosynthetically by the lake's
primary producers (algae and macrophytes) is consumed by herbivores
(grazers) that range from tiny zooplankton to snails to grazing minnows. Her-
bivores, such as the zooplankton, are- fed on . by planktivores (including
predatory zooplankton and planktivorous fish) that, in turn, provide a food
source for the higher-level consumers such as piscivorous fish (bass,, walleye,
trout) and fish-eating birds (kingfishers, herons, ospreys, eagles). This general
progression of feeding'levels (also called trophic levels) from primary
producers, to herbivores, to planktivores, to the larger predators, constitutes
the food chain (Fig. 2-10). The actual complex of feeding the interactions that
exists among all of the lake's organisms is called the food web. '
As shown in Fig. 2-10, the food chain concept also involves the flow of
energy among the lake organisms and the recycling of nutrients. The energy
flow originates with the light energy from the sun, which is converted by green
plant'photosynthesis into the chemical bond energy represented by the organic
matter produced by the plants. Each subsequent consumer level (herbivore,
planktivore, piscivore) transfers only a fraction (usually only about 10 to 20 per-
cent) of the energy received on up the chain to the next trophic level (Koz-
lovsky, 1968; Gulland, 1970).
NUTRIENTS
NUTRIENTS
BENTHIC
ORGANISMS
PISCIVQRES
HERBIVORES
PLANKTIVORES
NUTRIENT
CYCLING*
((-
\\'
X^ / PRIMARY
I
t
I
ENERGY
FLOW
i
I
I
I
'PRIMARY \<^UNOGFPf
PRODUCERS \^—i
V /BACTERIA & BENTHIO ,
DETRITIVORES, \ |
ORGANIC MATTER
DECOMPOSITION
Flaure 2-10.—The food-chain concept refers to th« progression of leading (or trophic) levels from primary producers, to her-
blvores, 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, her-
bivores, and planktivores Is required to support a few large game fish. ,
26
-------
In practice, this means that a few large game fish depend on a large, supply
of smaller fish, which depend on a very large supply of smaller herbivores,
which depend on a successively much, larger base of photosynthetic produc-
tion by phytoplankton and other aquatic plants. Finally, by constantly producing
wastes and eventually dying,, all of these organisms provide nourishment to
detritivores (detritus-eating organisms) and to bacteria and fungi, which derive
their energy by decomposing organic matter. Organic matter decomposition
results in the recycling of nutrients that are required for further plant produc-
tion.
A more complex view of energy flow ancf nutrient cycling in a lake or reser-
voir ecosystem is shown in Fig. 2-11. Much of the organic matter input from the
watershed directly supports the growth of detritivores, bacteria, and fungi. A
significant fraction of the in-lake primary production' provides food for her-
bivores and, ultimately, for higher consumers (as described before); however,
much of the in-lake plant production may also become detritus and provide
nourishment to both planktonic and benthic detritus feeders. Sorption of dis-
solved organic compounds to suspended detritus particles, microbial coloniza-
tion of these particles, and particle aggregation or clumping produces
microbial-detrital aggregates large enough to be consumed by filter-feeding
zooplankton. Additionally, the sedimentation of detritus particles to the lake
bottom provides energy to the benthic detritivores, which are preyed upon by
the higher consumers. Nutrient regeneration occurs at virtually every level of
the food web, and only a small fraction of the organic matter produced ul-
timately accumulates as permanent bottom sediment.
ORGANIC
^.3*- MATTER SUPPLY
/
t
(NUTRIENTS)
PLANKTONIC
FILTER-FEEDERS
PARTICULATE
DETRITUS
«
(NUTRIENTS)
HIGHER
CONSUMERS
i
k
I
\
MICROBIAL^
COLONIZATION.
PARTICLE
AGGREGATION
t
SEDIMENTATION
X
I
I
J
/I
BENTHIC
•—— DETRITIVORES—'
Figure 2-11 .—A more complex view of energy flow and nutrient recycling In a lake or reser-
voir. Solid lines represent pathways of energy flow, and dashed lines Indicate nutrient recy-
cling. Refer to the text for a detailed explanation. Modified from Goldman and Klmmel
(1978). .
27
-------
Lake Aging and Cultural
Eutrophication
Lakes are temporary features df the landscape. The Great Lakes, for example,
have had 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 result of
climate, movements in the earth's crust, shoreline erosion, and the accumula-
tion of sediment. Lake eutrophication is a natural process resulting from the
gradual accumulation of nutrients, increased productivity, and a slow filling in of
the basin with accumulated sediments, silt, and organic matter from the water-
shed.
The original shape of the basin and the relative stability of watershed soils
strongly influence the lifespan of a lake (see the boxed section and Fig. 2-D on
lake basin origin and shape).
The classical lake succession sequence (Fig. 2-12) is usually depicted as a
unidirectional progression through the following series of phases or trophic
states: , . ' .
• Oligotrophy: Nutrient-poor, biologically unproductive
*•
• Mesotrophy: Intermediate nutrient availability and biological
productivity
• Eutrophy: Nutrient-rich, highly productive
• Hypereutrophy: Pea-soup conditions, the extreme end of the
eutrophic stage
These lake trophic states correspond to gradual increases in lake produc-
tivity from oligotrophy to eutrophy (Fig. 2-12). . .
Evidence obtained from sediment cores (see Chapter 3), however, indi-
cates that changes.in lake trophic status are not necessarily gradual or
unidirectional. If their watersheds remain relatively undisturbed, lakes can
retain the same trophic status for many thousands of years. Oligotrophic Lake
Superior is a, good example of this. In contrast, rapid changes in lake nutrient
status and productivity are often a result of human-induced disturbances to the
watershed rather than gradual enrichment and filling of the lake basin through
natural means.
Human-induced cultural eutrophication occurs when nutrient, soil, or or-
ganic matter loads to the lake are dramatically increased. A lake's lifespan can
be shortened drastically by activities such as forest clearing, road building, cul-
tivation, residential development, and wastewater treatment discharges be-
cause these activities increase soil and nutrient loads that eventually move into
the lake. Chapter 5 explains watershed influences from these activities in the,
sections on nonpoint and cultural sources. • .
Some.lakes, however, are naturally eutrophic. It is important to recognize
that many lakes and reservoirs located in naturally fertile watersheds have little
chance of being anything other than eutrophic. Unless some other factor such
as turbidity or hydraulic residence time intervenes, these lakes will naturally
have very high rates of primary production.
Natural and man-made lakes undergo eutrophication by the same proces-
ses—nutrient enrichment and basin filling—but at very different rates. Reser-
voirs become eutrophic more rapidly than natural lakes, as a rule, because
28
-------
NATURAL EUTROPHICATION
MAN-INDUCED EUTROPHICATION
OLIGOTROPHY
EUTROPHY/
HYPEREUTROPHY
FERTILIZERS AND
PESTICIDES
EUTROPHY/
HYPEREUTROPHY
Figure 2-12.— (left column) .The progression of natural lake aging or eutrophlcatlon
through nutrient-poor (ollgotrophy) to nutrient-rich (eutrophy) sites. Hypereutrophy repre-
sents extreme productivity .characterized by algal blooms or dense macrophyte popula-
tions (or both) plus a high level of sedimentation. The diagram depicts the natural process
of gradual nutrient enrichment and basin filling over a long period of time (e.g., thousands
of years). . -
(right column) Man-Induced or cultural eutrophlcatlon In which lake aging Is greatly ac-
celerated (e.g., tens of years) by Increased Inputs of nutrients and sediments into a lake, as
a result of watershed disturbance by humans.
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 outlets, are considerably more efficient at
trapping sediments than at retaining nutrients, and therefore the filling of their
basins with river-borne silts and clays is the dominant aging process for these
waterbodies. • . - '
However, reservoirs often do not go through the classical trophic progres-
sion from oligotrophy to eutrophy, as described for natural lakes. In fact, newly
.filled impoundments usually go through a relatively short period of trophic in-
29
-------
Lake Basin Origin and Shape
The origin of the lake basin often determines the size and shape of the lake, which, in
turn, influences the lake's productivity, water quality, the habitats it offers, and its
lifespan. , .
Glacial activity has been the most common origin of lake basins in North
America (Fig. 2-E). Glacial lakes of Canada and the upper midwestern United States
were formed about 8,000 to 12,000 years ago. Some lake basins resulted from large-
scale glacial scouring—the wearing away of bedrock and deepening of valleys by
expansion and recession of glaciers. Deep depressions left by receding glaciers filled
with meltwater to form lakes. The Finger Lakes of upper New York State were
formed this way.
DURING GLACIATION
About 3.000 years ago the list
glaciers began to retreat from the.
North American continent. Many of
the small Inices In the upper midwest
and north central states as well as
Canada were formed bv nuge Ice
blocks buried In the loose rock and
soil and deposited by the glaciers.
When the buried ice blocks melted
they left holes in'Me glacial till
which tilted with water from the
melting glaciers.
GLACIAL TILL
AFTER GLACIATION
Chains of likes formed along some
streams that drained the melting *
glaciers. Other lakes were created
between the moraines and the
retreating ice mass from the melting
water.
MORAINE
A Moraine ht a ridge ot low rolling
hills made up of unsorted rocks and
soil deposited when the glacial ice
mass meltvd.
Figure 2-E.—The effects of glaciation In shaping lake basins.
Kettle or "pothole" lakes, which formed in the depressions left by melting ice
blocks, are very common throughout the upper midwestern United States • and large
portions of Canada. These lakes and their watersheds are popular home and cottage
sites and recreational areas. The size and shape of the kettle lake basins reflect the
size of the original ice block and how deeply it was buried in the glacial debris.
Natural lakes have also been formed by volcanism; Crater Lake in Oregon is an
example. Large-scale movements of-large segments of the earth's crust, called tec-
tonic activity, created Reelfoot Lake in Tennessee and Lake Tahoe in California,
among others.
Solution lakes are formed where groundwater has dissolved limestone; Florida
has a number of these lakes. Lakes may also originate from shifting of river chan-
nels; oxbow lakes are stranded segments of meandering rivers. Finally, natural lakes
can also be created by the persistence of the dam-building beaver.
30
-------
stability in which a highly productive period (termed the "trophic upsurge") is
followed by a decline in lake productivity (called the "trophic depression"), and
the eventual establishment of a less productive but more stable trophic state
(Fig.-2-13). 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 from the decomposition of ter-
restrial vegetation and litter), which results in high productivity of both plankton
and fish. ;
The trophic depression is, in fact, the initial approach of the reservoir sys-
tem toward its natural productivity level dictated by the level of external nutrient
inputs. However, reservoir fish production depends on a complex of factors
that affect both trophic and habitat resources. Flooding of soils, vegetation,
and litter as the new reservoir fills contributes to both abundant food and ex-
panding habitat. As the reservoir matures, both food and habitat resources
decline, fish production decreases, and the fish community stabilizes.
The trophic upsurge and depression or "boom and bust" period of trophic
instability in reservoirs has received much attention from limnologists and
fishery biologists because it inevitably produces both initial concerns about
poor water quality and simultaneously raises false hopes for a higher level of
fishery yield than can be sustained over the long term/Ultimately, in reservoirs
and in natural lakes, the nature of the watershed (or human-induced changes
of the watershed) will determine the water-quality, biological productivity, and
trophic status of the system. •
Ecology's Place in Lake
Protection, Restoration, and
Management
The goal of this chapter on ecological and limnological concepts is to provide
the reader .with a basic background for understanding the environmental fac-
tors controlling lake productivity, water quality, and trophic status. This back-
ground is intended to help the reader evaluate the potential benefits and limita-
tions on lake protection and restoration approaches and techniques described
in the rest of this Manual.
This Manual emphasizes two basic, complementary approaches to lake
restoration and management for water quality:
1. Treat the causes of eutrophication. This approach involves limiting lake
fertility by controlling nutrient availability.
. 2. Treat the products of overfertilization and thus control plant production
in the lake.
Methods employed to control nutrient availability include proper watershed
management practices, advanced treatment of wastewater, and diversion of
wastewater and stormwater (see Chapter 5). Hypolimnetic withdrawal, dilution
and flushing, phosphorus precipitation and inactivation, sediment oxidation,
sediment removal, and hypolimnetic aeration are techniques to deal with
nutrients already in the lake system; they are discussed in Chapter 6.
31
-------
(a)
NUTRIENT INPUTS
'(2)
(1)
• — —(3)
LU
O
CO
UJ
>
Us
111
tr
(b)
AVAILABILITY OF HABITAT AND DETRITUS
HABITAT
LABILE DETRITUS
(c)
BIOLOGICAL PRODUCTIVITY
'/~\ PLANKTON
\
UPSURGE
-r-
DEPRESSION-
-\
TROPIC
TROPHIC
'STABILITY'
INSTABILITY 7 I
BASIN FILLING BEGINS
RESERVOIR AGE
Figure 2-13.—Factors Influencing biological .productivity or "trophic progression" In a
reservoir 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
habitat (flooded vegetation) and labile terrestrial detritus'supporting macrolnvertebrates
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).
32
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Methods used to control plant biomass include artificial, circulation, water-
level drawdown, harvesting, chemical'treatments (herbicides and algicides),
biological controls, and shading and sediment covers for macrpphyte control.
Chapter 6 also provides details-on these techniques.
How to determine what needs to be treated and where problems; may
originate is discussed in Chapter 3. Chapter 5 gives further, information on
watershed influences and how to manage them.
Most of what we know about lake and reservoir restoration has been
learned in the last 15 years through experience gained from^many studies con-
ducted in the United States, Canada, Europe, and Scandinavia. Experience
gained from previous restoration .efforts clearly leads to the following con-
clusions: .-••''.
1. 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. .....'"
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. Efforts to control both
external loading of nutrients from the watershed and internal nutrient
loading and recycling are often required to produce a noticeable
improvement in water quality.
4. The physical, chemical, and biological components of lake ecosystems
are intricately linked. Lake restoration or management efforts to
. enhance water quality by limiting nutrient availability and thereby
reducing algal production will also decrease fish production. Decisions
must be made and priorities must be set.
5. To be successful, lake restoration and management objectives must be
compatible with 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, the
regional seating, and the nature of the watershed. Important factors include
hydrology, climate, watershed geology, watershed to lake ratio, soil fertility,
hydraulic residence time, lake basin shape, external and internal nutrient load-
ing 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 management or restoration ef-
forts to transform such a system to arrunproductive,-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 these effects can be reversed and
the lake's condition can be improved or restored by an appropriate combina-
tion of management efforts in the watershed and in the lake itself. The best
situation is one where steps are taken to protect the lake's watershed before
problems develop.
33
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In the chapters to follow, a variety of lake and watershed management tech-
niques are discussed and compared. While reading through this information, it
is important to remember that the potential effectiveness of any lake restora-
tion method or combination of methods will depend entirely on the ecological
soundness of its application. Recent experience in lake restoration has clearly
shown that there is no panacea for lake restoration or for lake management
problems. That is (despite the salesperson's claims), introducing grass carp,
harvesting weeds, or installing an artificial aeration/destratification system is
not necessarily the solution for a particular lake. In fact, all three of the,se com-
monly used methods address symptoms rather than causes.
Finally, lakes and their watersheds are tightly coupled. Therefore, to be ef-
fective, lake and reservoir restoration and management efforts must consider
both watershed processes and lake dynamics.
34
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Chapter 3
PROBLEM
IDENTIFICATION
Chapter Objectives
In.the first chapter of.this Manual, a lake problem was defined as a limitation oh a
desired use of the lake. Based on this definition, problems can often be identified
by simply listing lake users' complaints. When boat owners find they cannot use
the lake for recreation because of weed infestation, for example, they have clear-
ly identified a problem. While this assessment is usually the first action in the
process of reaching a solution, a number of other steps (Fig. 3-1) must be taken
before lake managers can implement a plan. .
Q The purpose of this chapter is to help lake users, managers, and associations •
•Identify problems;
• Put problems in perspective for a particular lake;
• Understand how the causes, not the symptoms of problems are
determined through diagnostic analysis; and :
•• Define the causes df the lake's problems.
Finally, Chapter 3 directs the reader to appropriate parts of this Manual to
evaluate alternatives for solving these problems.
Common Lake Problems
Most types of problems commonly occur in a number of lakes within a region;
rarely is a problem unique to a particular waterbody. Some of the impaired uses,
.possible causes, and widely occurring lake,problems are listed in Table 3-1.
Among the latter, poor fishing, overabundant algae, excessive' maorophytes, lack
of depth and user conflicts are frequent public complaints that provide good ex-
amples of the relationship between lake users and lake conditions.
' . ' ••' • ' . ' •• . '• " . '35
-------
Problem Identification
Common lake problems
' • (See Chapter 2 for reasons)
Algal scums - Poor fishing
Weeds - Odor
Color and muddy waters
Overcrowding/user conflicts
Problem statement
(symptoms)
Lake users
Lake association
Community
Private
Sector
Universities <
Consultants
Contractors
Organizations
Problem identification
Possible
causes
Perception
Problem diagnosis
Available data
Data collection
Modeling techniques)
Indices j (See Chapter 4)
Problem definition
Possible solutions
. Watershed
Management
(See Chapter 5)
"V
In-lake
Restoration
(See Chapter 6)
J
Lake management plan
(See Chapters 7, 8, 9)
Public
Sector
Local
Federal
State
Figure 3-1.—General approaches can be described for defining lake problems in terms of
users' needs and investigating causes to reach a solution thai fits both the lake's capabil-
ities and the needs of users. ''
36
-------
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37
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Algae: Small aquatic
plants that occur as
single cells, colonies, or
filaments.
Algae
One of the sources of food and energy for fish and other lake organisms, algae
are a vital part of all lakes (see Chapter 2). Too many algae and the wrong
kinds, however, can interfere with some lake uses by, among other, things,
clogging the filters in drinking water treatment plants, inhibiting the growth of
other plants by shading them, contributing to oxygen depletion and fishkills,
and causing taste and odor problems in water and fish. Organic matter
produced by algae can react with chlorine; trihalomethanes—possible products
of'this chemical reaction—are believed to cause cancer. Lastly, some species
of algae release toxins.
The most common use of lakes is aesthetic enjoyment, and excess algae
can interfere with this simple pleasure. Unsightly scums are usually caused
either by tangled masses of filamentous algae or by "blooms" of certain
planktonic algae that float on the lake's surface. The regular occurrence of
visible algal blooms often indicates that nutrient levels .in the lake are too high.
Weeds
Weeds also limit many lake uses. Like algae, weeds (or aquatic macrophyt§s)
are a vital part of the lake (see Chapter 2) b.ecause they provide cover for fish
and food for wildlife. However, too many weeds can limit swimming, fishing,
skiing, sailing, boating, and aesthetic appreciation. Indeed, getting rid of
noxious weeds is one of the most common projects among lake associations.
Fifty percent of Wisconsin's lake districts report weed harvesting programs,
and 25 percent use herbicides (Klessigetal. 1984).
Depth
The loss of lake volume, or infilling, is a problem in a majority of lakes and
reservoirs. Depth problems result from the loss, of volume because of in-
creased sediment loads that can originate externally as soil erosion in the
watershed or internally from decaying algae and weeds in the lake itself. In-
creased sediment generally leads to turbid or murky water, and reduction in
depth usually disrupts swimming, boating, and sailing and encourages exten-
sive weed growth. Dredging has been one of the major lake restoration ap-
proaches used in lake management. Dredging, however, does not stop soil
erosion in the watershed, which is the main cause of lake infilling.
Acidity
Acidic lakes are found in areas where the watershed soils have no natural buf-
fering capacity. Acid rain and other manmade or natural processes can further
contribute to lake acidjty; Acid rain (scientifically referred to as "acidic deposi-
tion") occurs in areas where the combustion of fossil fuels increases the con-
centration of atmospheric sulfur and nitrogen oxides. These, acids can be
transported thousands of miles and deposited back to earth in precipitation or
as dry particles.
Drainage from naturally acidic organic soils also contributes to lake acidity,
and these soils often become more acidic through land use practices such as
logging, reforestation,'and mining. Acidic outflows from abandoned mines af-
38
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feet thousands of miles of streams and numerous lakes throughout Ap-
palachia; acid mine drainage also occurs in the coal fields of Illinois, Indiana,
and Ohio, and in coal and metal mining areas in the western States.
Most aquatic plants and animals are sensitive to acidity. Fish, especially,
are negatively impacted; in fact,rmany acidic lakes have no fish. Fish popula-
tions may be restored by reducing the sources of acidity reaching a lake. Addi-
tion of base materials (liming) has been the major restoration technique for
acidic lakes.
User Conflicts
Not all problems occur because of physical, chemical, .and biological condi-
tions. User conflicts arise from limitations on the time and space available for
recreational activities, and some lake uses clearly conflict with others. Motor-
boating can disrupt fishing, swimming, and scuba diving, and just the sound of
boat motors can disturb aesthetic pleasures. -
As discussed in Chapter 2, management practices for water quality and
sport fishing are occasionally in direct conflict. Mudflats created by lake draw-
down for power generation or water supply vie with the desire to have a con-
stant water level for aesthetics, docking boats, and wading. In fact, conflicts
about desired lake uses can cause greater problems than algal scums or an
Overabundance of weeds. ; ,
Problem Statement
A local homeowner or lake user will probably be aware of lake problems before
a professional lake manager suggests that something is wrong. If a boater can-
not move across the shallow areas because of dense macrophytes or a swim-
mer cannot enjoy a dip without tangling with weeds, there is a problem. If a
homeowner is offended by the smell of decaying macrophytes and algae from
the lake, a problem exists.
For these Jake users, the most productive response is to form an organized
group to deal with the problems and to determine the interest in seeking a solu-
tion. Local initiative is an important part of lake restoration; it helps users un-
derstand how the lake works (and their role in the problems) and enables them
to cooperate in the solution. Determining why problems exist and how serious
they are relative to the natural carrying capacity of the lake, however, typically
requires professional assistance. ' ,
Lake organizations invariably would like to see their lake do everything.
They want aesthetic pleasure, great fishing, healthy water, sandy shorelines
and bottoms, and a healthy wildlife population — all without insects or weeds.
Unfortunately, almost no lake can meet all of these demands. Systematically
clarifying the attainable uses in a lake management" effort must be the first step
of any plan.
Local users, homeowners, or lake associations have two responsibilities in
lake restoration that require considerable attention. The first is to come to
some agreement on what the problems are, clearly state these problems; and
determine how to organize to resolve them. Appendix 3-A describes two
democratic procedures—the nominal group process and the Delphi process—
that may prove useful for this responsibility. The second responsibility is to as-
39
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sure that analysis' of the causes of problems and a viable response to these
factors is carried out by competent professionals.
Based on both what the users want and what the lake itself is capable of
supporting, problem identification focuses first on establishing a :set of realistic
uses desired in the lake.
Problem Identification
Problem Perception
Depending on physical characteristics of the lake basin, the watershed, and
the quality of incoming water, lakes are suited to particular purposes. Table 3-2
summarizes general lake types that are suited to specific uses.
Table 3-2. — Priorities for lake use based on lake characteristics
SIZE OF LAKE
DEPTH
CLARITY
SMALL LARGE SHALLOW DEEP TURBID CLEAR
(LESSTHAN (OVER500 (LESSTHANS' (OVER2O') (SECCHI (OVERS')
USES 10 ACRES) ACRES) AVG. DEPTH) UNDER 2') '
Water . - . - +. - • .+ v :- ' + '
Supply
'Rshing/ + + -/+ , . +' , —/+ .+
Wildlife
Swimming/ +/- + - + - +
Skiing
Boating/ - + ' - + '+ +
Sailing
Aesthetics + . + + + - •+
— » not suitable
+ •< suitable .
*/- = suitability depends on modilying factors
Although it may be technically possible to drastically alter a lake to meet the
needs of a certain user group, the cost will be high, and the decision is usually
unwise. It is important to determine lake uses that can realistically be attained
when choosing a desired use. Some lakes can never be crystal clear, no mat-
ter what measures are taken. If the watershed area is large relative to lake sur-
face area and watershed soi|s are highly erodible and nutrient-rich, the lake will
always have excessive algae and weed growth regardless of any lake treat-
ments. . ' '" '
Regional differences in lakes across the country represent an important fac-
tor in understanding the limitations of lake management. These differences are
distinct enough to group lakes in areas called ecoregions (Ornernik, 1987).
Regional differences in geology, soils, land use, and vegetation in these
ecoregions result in very different lake quality. Lakes in northern Minnesota, for
example, have lower nutrient and algal concentrations and greater transparen-
cy than lakes in southern Minnesota where there are more naturally fertile
soils. Reservoirs often are more turbid than natural lakes. Because lake users
40
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from different regions of the country may perceive a problem in local lakes that
is a natural phenomenon, it is important to delineate both natural and man-
made causes. . , .
Sometimes, users .perceive a Jake problem for which a source or cause
might not exist. Perceived problems should be addressed; they are no less im-
portant than real problems with underlying causes. For example, if people
won't swim in a lake because 15 years ago sewage was discharged into a
tributary, they are reacting to historic conditions. People perceive a continuing
situation, even though the problem was resolved more than a decade ago. It is
important to distinguish between real and perceived problems, but it is equally
important to identify and deal with the causes.
Causes of Lake Problems
Since most problems occur in a number of lakes in the region, the general
causes and approaches for solving them are usually known. While the solution
for each problem must be Jake-specific because every lake has unique charac-
teristics, general approaches can be described for defining lake problems and
causes (see Fig. 3-1).
. Identifying the potential causes of lake problems requires an understanding
and appreciation of the interactions not only among components within the
lake such"as algae, macrophytes, fish, and other organisms but also the inter-
actions between the lake and its watershed (see Chapters 2 and 5). In some
situations, a natural combination of these factors may dictate that a lake will be
highly biologically productive and that management and restoration efforts to
Iransform such a system to an oligotrpphic state would be ill-advised.
If, however, a lake has become eutrophic or has developed other water
quality problems as a result of manageable problems (such as an increased
.nutrient load from manmade causes), then these effects can be reversed, and
the condition of the lake can be improved or restored by an appropriate com-
bination of management efforts in both the watershed and the lake itself.
Delineation of natural versus manmade causes of problems can be en-
hanced by looking at other lakes in the same region. If there are some that
have similar water quality but relatively undisturbed watersheds, then the
specific lake's problems might occur from natural causes. However, if other
lakes in the region with relatively undisturbed watersheds have the desired
water quality, then manmade causes are probably contributing to the former
lake's problems and should be identified. Using other lakes in the region with
relatively undisturbed watersheds^ reference is a good way to initially assess
the potential impacts of manmade sources to the lake's problems., "
There are numerous tools for identifying causes of lake problems. Qualita-
tive approaches, such as comparing the-target lake to surrounding lakes,
document subjective observations, which can reveal important patterns. Quan-
titative approaches, such as the models discussed in Chapter 4 and trophic
state indices, rely on objective data.
In practice, both.qualitative and quantitative approaches are.usually con-
sidered. Using these methods to identify underlying causes of problems usual-
ly requires professional assistance. An important step in problem definition,
therefore, is selecting a,competent consultant or firm to interpret the results of
various diagnostic approaches.
Oligotrophic: 'Poorly
nourished, "from the
Greek. Describes a lake
with low plant productivity
and high transparency.
41
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Limnology: Scientific
study of fresh water,
especially the history,
geology, biology,
physics, and chemistry
of lakes. Also termed
freshwater ecology.
Selecting a Consultant
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 en-
gineering, limnology, biology, or other disciplines associated with lake manage-
ment; past performance in conducting similar' studies or dealing with similar
problems; and the firm's or candidate's capabilities (support staff or office
facilities) to address the problems in the lake. A series of questions related to
these criteria are listed in Table 3-3 and can be used to help select a consultant
or contractor. These questions need to be tailored to the particular set of lake
problems and should not be considered all-inclusive. The questions, however,
should assist the lake manager and lake associations in thinking about ap-
propriate questions to ask when seeking professional assistance.
Table 3-3.—Criteria for selecting consultants and contractors
A. Experience
1. How many lake restoration projects have they performed and for whom (refer-
ence and dates)? .
2. Have they successfully submitted Phase I and Phase II applications and ob-
tained EPA and/or State funding?
3. Have they performed Phase I Diagnostic/Feasibility Studies?
4. Have they managed Phase II Implementation Projects?
5. Have they worked on integrated watershed lake management projects?
6. Have they ever developed ordinances, zoning recommendations, or other institu-
tional approaches for protecting lakes?
7. Do they have experience with both structural and nonstructural management
techniques and procedures?
8. Have they prepared environmental assessments or impact statements?
B. Expertise
1. Dp they have interdisciplinary capabilities (i.e., engineers, limnologis'ts,'chemists,
biologists)? ' •
2. Are they familiar with the EPA and State regulations for Clean Lakes studies?
3. What is the educational background of the project team?
C. Past Performance
1. Have they worked as a prime contractor before or primarily as a subcontractor?
2. Have they ever had cost overruns? If so, how much and why?
3. Have previous projects been completed on time?
D. Company Capabilities
1. Do they do everything in-house or do they use subcontractors?
2. Do they perform the chemical analyses themselves or in a contract laboratory?
3. Do they have the capability to collect and evaluate water quality and biological
data? ' .
4. Do they have a quality assurance/quality control (QA'QC) program?
5. Do they have experience in the following areas?
a. Analyzing physical, chemical, and biological factors
b. Performing nonpoint source studies, including setting up automated monitor-
ing stations and stream gaging stations
c. Analyzing the trophic condition of the lake .
. ' d. Analyzing the status of the fish community and estimating the potential quality
of the fishery and production yield
e. Analyzing wet and dry weather data to calculate a reliable annual nutrient and
sediment loading budget . . -
ff Evaluating best management practices and in-lake restoration techniques
g. Analyzing institutional approaches for implementation of proposed manage-
ment and in-lake restoration activities
h. Assisting in public participation activities
i. Understanding and working with the EPA Clean Lakes Program ,
42
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Problem Diagnosis
- ' • I-.
Investigate the Problem
After selecting professional assistance and identifying lake problems, the next
step is to diagnose and quantify the problems and determine their causes. Al-
though this process should be guided by a professional consultant, the lake
manager and/or lake association must understand the steps in problem diag-
nosis to effectively manage and protect the lake.
Problem diagnosis is a process that provides greater quantitative resolution
on the sources or causes of the lake problems with each step. Once the
causes of the lake problems are clearly defined, then several alternative water-
shed management practices (Chapter 5) and lake restoration techniques
(Chapter 6) can be evaluated to reduce or resolve these problems.
At this stage, problems have been identified by the lake users, and poten-
tial causes generally are known. Problem diagnosis identifies which of the
potential causes are contributing to the problems and determines their relative
importance.
Diagnosis is generally a two-step process: (1) collating and evaluating ex-
isting data and (2) collecting and analyzing additional data. The first step,
using existing data, might be sufficient in some instances to provide enough
problem resolution for evaluation of alternative control strategies. Generally,
additional data are required, but this first step, at a minimum, identifies major
data gaps and aids in the design and implementation of a more cost-effective
and efficient data collection program.
Preliminary Analyses
Preliminary analyses include obtaining any existing information available on
both the watershed and the lake and making .a few basic back-of-the-enveiope
or desk-top calculations. Typically, a considerable amount of information will be
available on the watershed and 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 on the watershed and lake. Water quality data might be
available on the inflowing streams or the lake itself. 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 diagnosis. Recent aerial photographs taken during mid^ to late
summer can show the extent of weed beds in the lake. Creel census records
from State fish or game agencies can provide valuable information on histori-
cal changes in the fish community and in relative lake productivity.
Watershed land use and topographic maps can be used to determine the
location and acreage of various types of crops in the watershed; the soil types
Jn the watershed, including their potential for erosion; and the location of feed-
lots and barnyards, residential developments, forested and open land, and any
conservancy districts. The locations of wastewater treatment, industrial dis-
charges, and storm sewers can be obtained from the sanitary district, city
health department, or State natural resource or pollution control agency. In ad-
dition, discharge data as well as data on organic matter (for example, BOD)
43
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Groundwater: Water
found beneath the soil's
surface and saturating the
stratum at which it is
located; often connected
to lakes.
Sccchi depth: A measure
of transparency of water
obtained by lowering a
black and white, or alt
white, disk (Secchi disk,
20 cm in diameter) into
water until it is no longer
visible. Measured in units
of meters or feet.
and nutrient concentrations in the wastewater discharge usually can be ob-
tained from the wastewater'treatment plant's discharge monitoring records
(DMR's), which are 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 Soil Conservation Service. Locations
of groundwater wells in the watershed also might be available from these
agencies, the local health department, or pollution control agencies.
Groundwater wells can indicate the direction of flow and loading to seepage
lakes (Fig. 3-2).
Existing monitoring data for temperature, dissolved oxygen, nutrients, and
algae (chlorophyll) in the inflowing stream or lake are invaluable in this phase
of problem diagnosis. Unfortunately, in many instances monitoring data are not
available for even Secchi depth determinations, which are quick and easy to
do. If monitoring data are available, the progressive deterioration of lake water
quality or onset of a lake problem might be traced back to some change in use
of the watershed land or the lake.
Water Septic
Table System
Ground-Water Observation
Wells .
38-mm PVC pipe 01
32-mm galvanized pipe
. Disturbed aquifer -
CAP-*
lipe or _,— | I
lized pipe V] r
Well screen •
Well point -
0.1 to 1.3 m
2.4 to 31.7m
-Ll
0.46to
0.91 m
Figure 3-2.—Groundwater observation wells.
44
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Existing data should be evaluated for clues on why problems are occurring
in the fake. This diagnosis is enhanced by performing some basic back-of-the-
envelope analyses involving the construction of a simple lake budget that ac-
counts for the input and output of organic matter, sediment, and nutrients to
and from the lake. Similar to a household budget that balances income versus
savings and expenses, the lake budget (for example) attempts to account for
the sources and total load of phosphorus entering the lake (income), the
amount retained in the lake that might stimulate algae or macrophyte growth
(savings), and the amount leaving the lake (expenses). The total phosphorus
load, as described in greater detail in Chapter 4, is an important diagnostic tool
in determining the potential cause of several lake problems. :
The potential sources of nutrients, sediments, and organic matter from
agricultural land uses, wastewater treatment plants, urban areas, and forests
can be identified. These types of land uses and levels of wastewater treatment
have been investigated, and some general nutrient and sediment export coeffi-
cients associated with various land uses have been published. These land use
coefficients can be used with the annual runoff coefficients and wastewater
discharge estimates to estimate the total load of material to the lake.
the relative contribution of the various land use activities or wastewater
treatment plants to the total lake load also can be determined. A rough es-
timate of the amount of material retained in the lake versus that flowing out of
the lake can be estimated based on the hydraulic residence time (see Chap-
ters 2 and 4). Quantities of materials such as phosphorus or BOD associated
with various levels of severity of problems in other similar lakes can be com-
pared with the quantity estimated for the lake under study.
The preliminary lake budget can indicate those land use activities—includ-
ing wastewater treatment—that appear to be contributing the greatest propor-
tions of organic matter, sediment, and nutrients to the lake and, therefore, war-
rant consideration for watershed management practices (see Chapter 5). The
budget also might indicate that loading from the watershed doesn't appear suf-.
ficient to produce the magnitude or severity of the lake's problems. Other fac-.
tors such as internal processing of material in the lake or an unmeasured and
unestimated component of the budget such as septic tank drainage or
groundwater may also be contributing material that is 'causing problems.
The budget approach provides limited information on internal lake proces-
ses, although it does provide insight into which processes might be important
based on external loads. High sediment loads indicate potential problems with
lake filling while high nutrient loads indicate algae or weed production is a
potential problem.
To refine the diagnosis and better define the cause of the problem, addition-
al data must be collected and analyzed. This data collection effort, however,
should be guided by the results of the preliminary analysis. If agricultural runoff
appears to be a major contributor to the nutrient and sediment load, for ex-
ample, then data collection efforts should focus on better estimates of loading
from the various agricultural locations in the watershed to determine which .
locations are contributing the greatest portion of the load to the lake. Waste-
water discharges to a lake are usually an important source of nutrients and or-
ganic matter. The relative contribution from wastewater treatment plant ef-
fluent, storm water sewers, or septic tank seepage to the lake can be
determined by collecting samples to characterize these inputs.
45
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Data Collection and Analysis
With the preliminary analysis as a guide, a data collection program can be
designed for problem definition. A typicaf data set for problem diagnosis will in-
clude measurements on
• Water budget: surface and groundwater inputs and changes in
lake level; .
• Physical parameters: sedimentation rate, temperature, and
transparency;
• Chemical parameters: dissolved oxygen and plant nutrients;
* Biological parameters: algae, macrophytes, a fish survey;
• Other parameters as required, such as alkalinity, pH, and
conductivity; and .
• Use of trophic state indices. '
Water Budget
Surface Water and Lake Level
Determining water flow into and out of the lake,. as well as recording changes in
lake level, are essential for determining the annual nutrient, organic matter,
and sediment loads to the lake and for establishing the carrying capacity of the
lake — the amount a lake or reservoir can assimilate each year without exhibit-
ing problems. • /
The first step is to establish a lake-level gaging station. This usually con-
sists of placing a staff gage in the lake and making regular readings, which are
most accurate when the water is calm. An alternative method is placing a still-
ing well that dampers out the effect of waves and continually, records water
level (Fig. 3-3). . .
Stream gaging stations are required on major tributaries as close to where
they enter the lake as possible and at the outlet of the lake. Gaging every
tributary to' a lake, however, is not usually required. The water yields from
monitored subbasins within the watershed can be substituted for similar un-
monitored basins. If obvious sources of pollution are recognized near a
tributary stream, then it is prudent to place another gaging station in the vicinity
of the pollution site.
Groundwater Measurements
The importance of groundwater nutrient contributions to a lake depends on the
size of the surface watershed contributing to the lake. For example, if the sur-
face watershed of a 1,000-acre lake is 50,000 acres, the water and nutrient in-
comes for that lake are probably dominated by surface inputs, and the
groundwater contribution might be of little consequence. However, if the water-
shed area around a 1 00-acre lake is only 300 acres, then the groundwater con-
tribution might become more important.
46 .
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Typical 1960 cost $5000 per installation.
From U.S. Geological Survey
Figure 3-3.—Conventional stilling well Installation for water stage recorder.
When managing groundwater-dorriinated seepage lakes such as those
found in Florida, Minnesota, Michigan, the New England States, New York, and
Wisconsin, the groundwater component of a nutrient budget becomes essen-
tial.
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
downhill. The actual definition of the groundwater component is determined 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, wells must be placed on the
surrounding land, and the water level in each well must be measured in rela-.
tion to the lake level (Fig. 3-4). Along with locating and placing of individual
wells, the variation of possible groundwater table slopes, soil types, bedrock
types and locations, and location of permeable nearshore sediments should be
evaluated. • . „-
In lieu of the well system approach, several other, more focused techniques
are often employed. These methods are used to locate specific areas within a
lake where groundwater is entering or leaving. Techniques include use of
seepage meters, small tube wells that are placed directly in the lake, tempera-
ture surveys, and fludrometric/conductivity measuring devices.
• A seepage meter is a device constructed by cutting off the top few
inches of a closed metal or plastic drum. A plastic bag with a known
quantity of water is then placed over an open hole on the top. Flow into
or out of the lake is determined by measuring the change in water
volume in the plastic bag over time.
47
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SUMMIT LAKE
A
N
ALGA LAKE
r-'
BOGUS SWAMP
Ground-water Observation Well
Figure 3-4a.—Groundwater observation well locations on Greater Bass Lake.
• Small tube wells, also called mini-piezometers, are essentially
very small tubes that are pushed into a lake's bottom sediments.
The water level within these tubes is measured to determine if
groundwater flow is into or out of a lake.
48
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1730
1710 -
1690 -
1670 -
1650
Stream Outflow to Greater Bass Lake
•^ Top of Ground-water Table
Figure 3-4b.—Cross section showing estimated groundwater table near Greater Bass Lake. In this case, the groundwater
table was always lower than the lake level and any Influence of the groundwater system, Including on-slte waste disposal
contributions to It, would be considered negligible.
Another method, most commonly used to explore the bottom of the
lake for contaminated, groundwater inflow areas, uses an instrument
called a fluorometer. The Septic Snooper is the commercial
tradename for a device that employs this technology. The
instrument works by pumping a continuous stream of lake water,
normally from nearshore bottom areas, through itself and
continually measuring changes of specific electrical conductivity
and fluorescence, which in some cases can be related to septic
seepage.
• Occasionally, location of groundwater inflow areas can be
determined by use of a simple thermometer that is pushed into the
lake's sediments. If done when a lake water/grpuhdwater
temperature differential exists (such as during late summer),
groundwater inflow areas can be located.
However, regardless of the method employed, it is important to remember
that groundwater flow into or out of a lake often .varies considerably from
season to season or year to year. For example, during times when the lake is
low, such as during the summer when evaporation is high", groundwater is
often found to be flowing into the lake. When lake water levels are high, as in
the spring, flow is often reversed, with the lake contributing to the groundwater.
Additionally, groundwater flow into or out of a lake is not usually uniformly dis-
tributed, being more concentrated in those areas of the lake (springs) where
bottom sediments are most permeable. I
"., 49
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Knowledge of "general groundwater flow direction and quantity can assist in
making judgments about the feasibility of sewering a lake. For example, in a
situation where soils are sandy and have little phosphorus retention capability,,
and when septic tank seepage easily flows into the groundwater, there may be
concern that nutrients will be delivered to a lake via the groundwater. In these
cases, for example, if it is found that the groundwater flow is always away from
the lake on the east shore and toward the lake on the west shore, then con-
sideration should be given to sewering only the west shore so that any
nutrients leached into the groundwater on the east shore will not be carried into
, the lake.
Unfortunately, most lake environments are not this simple, and additional
evaluations are often necessary to defirie the effects of on-site wastewater dis-
posal systems. Most groundwater evaluations require experienced profes-
sionals, so these studies are usually conducted by consultants, university
faculty, and State and Federal agencies.
On-site Septic Systems
Evaluations of nutrient loadings to a Jake from on-site disposal systems require
,a detailed, site-by-site inspection and evaluation of each individual system.
When combined with information on how frequently .systems are used, how
much water they handle, how well they are maintained, and so forth, good first-.
cut estimates of the potential nutrient loads contributed from these systems
can,be made.
It is very common for residents living around a eutrophic lake to suspect on-
site waste disposal systems as the major culprit causing their lake problems.
Unfortunately, little quantitative information exists that compares measured
nutrient loadings from on-site waste disposal systems to the total nutrient load
received by a lake. As a result of over-estimating the importance of on-site sys-
tems, many lakes have been sewered at large expense with no resulting im-
provement in water quality. „
.In detailed studies of 13 developed lakes in Wisconsin where on-site sys-
tenis were examined, phosphorus contributions from these systems were
measured and found to have provided between 1 percent and 33 percent of a
lake's total nutrient load. When compared to the total phosphorus budget for
these lakes, the contributions from the disposal systems did not have a sig-
nificant impact on the overall trophic condition of these lakes.
If the results of the physical site-by-site evaluation of existing waste dis-
posal systems suggest they may be contributing a significant nutrient loading
to a lake, then selected sites around the lake should be included as part of a
more comprehensive study to define lake problems.
As described in Chapter 5, on-site systems for the disposal of domestic
wastes frequently employ a septic tank to remove settleable and floatable
solids and to store the sludges and scums. As.a result of bacterial decomposi-
tion in the tank, approximately 40 percent of the solids passing from the waste
source to the septic tank are broken down and pass on to the soil absorption
area, which may be a bed, pit, or trench or some combination of artificially
placed materials and the natural soil. The soils in the absorption field then
react with the septic tank effluent, providing further treatment.
Calcium, aluminum, and iron compounds associated with soil particle sur-
faces are particularly important when considering the ability of soils to remove
phosphate ions from septic tank effluent. The phosphate ion binds relatively
50
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tightly to'soils containing iron and aluminum in neutral to acidic soils or calcium
in neutral to alkaline soils. -
There have been several approaches; used to determine how on-site dis-
posal systems affect the nutrient budget of a lake, all of which have significant
limitations. The most direct method involves making actual phosphorus meas-
urements in the groundwater from observation wells located around individual
adsorption fields. Other methods include sampling water collected from
seepage meters or mini-piezometers placed over lake sediments identified as
contributing zones. If'high concentrations of phosphorus are isolated in the
seepage meter waters, they are often assumed to have originated from a
waste disposal system.
The capacity of the soil beneath the absorption field to sorb phosphorus
can also be determined by taking plugs of soil from the area between the drain
field and the lake, followed by laboratory tests to determine how much phos-
phorus the soils can still adsorb. If the soil's capacity to sorb phosphorus is still
large, and wastewater is seeping adequately through the soils, phosphorus is
probably being retained by the soils and is not reaching the lake. If it is deter-
mined that the soil's capacity to adsorb phosphorus is minimal, than it might be
assumed that inadequately treated wastewater will probably leach into the
lake. • , •
Water Quality Monitoring
Sampling Sites
Sampling locations and depths influence the conclusions drawn from the data
collected in the lake, so it is important that these stations accurately represent
lake conditions. -
The sampling locations and depths for physical, chemical, and biological
analyses are associated directly with the properties of the lake. In lakes that
are almost round, a single station located over the deepest point may be ade-
quate. In lakes with branched, finger-like shorelines or multiple embayments,
or long, narrow, natural lakes and reservoirs where significant gradients in
water quality might exist, more stations will be needed (Fig. 3-5).
In shallow lakes that mix continuously throughout the summer, fewer sta-
tions will be needed, and samples taken at the surface, mid-depth, and bottom
would be adequate. An integrated sample from the surface to just above the
sediment would be better. '.,'-..
In deep, stratified lakes, samples should be collected at least near the sur-
face, in the metalimnion near the middle of the hypolimnion, and near the bot-
tom (see Chapter 2). One station should be at the deepest part of the lake with
other stations located, in the shallower areas and prominent bays. For reser-
voirs, stations should be located at the river inflow, below the plunge point, per-
haps near the middle, and at the deepest point near the dam.
51
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Long, 'large lakes
Inlet
Outlet
Lakes with distinct lobes or isolated bays
. ' Inlet
Outlet
Figure 3-5.—Typical sampling locations for lakes with simple and complex shapes.
Physical Parameters
Sedimentation Rate Estimates
There are two generally accepted methods to determine recent sedimentation
rates in lakes and reservoirs. Qne method involves the determination of the
radioisotopes Cesium-137 or Lead-210 in the sediments. Although this method
provides accurate estimates of sedimentation rates, it is relatively expensive.
The second method, which is far less sensitive but also much less expen-
sive, is to compare 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. For natural lakes and reservoirs receiving large sediment
loads, this method is satisfactory.
The usefulness of these methods depends on the objective of the study.
One use of sediment dating is in proposed dredging projects. Before any major
dredging is undertaken, the rate of sedimentation should be determined. It is of
little value to dredge a reservoir that is filling in at a rate of 2 inches or more a
52
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year if watershed controls for erosion are nor implemented. In general, natural
lakes fill; in at a slower rate than reservoirs, with rates for lakes ranging from
0.10-0.50 an inch per year.
Temperature
Temperature patterns or thermal stratification (see Chapter 2) influence the
fundamental processes occurring in a lake such as dissolved oxygen deple-
tion, nutrient release, and algal growth. Temperature measurements are use-
ful, for example, in deciding whether a shallow lake mixes periodically
throughout the summer. If a shallow lake is suspected of thermally stratifying
for brief periods and then mixing, weekly measurements should be taken
during the summer. Deeper lakes that remain stratified throughout the summer
may not require a high frequency of sampling for temperature to understand
general temperature patterns occurring there.
An example of thermal stratification and mixing periods is shown in Figure
3-6 for Pickerel Lake over a two-year period. This figure represents the type of
information a professional consultant will collect and analyze as part of a lake
restoration program. The algal problems associated with this shallow lake (40
acres, 17-foot maximum depth) are directly related to the timing of the summer
mixing period. When the lake mixed in mid-September, clumps of blue-green
algae that were on the lake bottom were suspended into the entire lake. Cold
weather prevented any prolonged algal bloom. However, the following year
1971
2
4
& 6
-c 8
•K
§-10
Q 12
14
16
19"72
Mix
N i D | J i F | M | A i Mi. J i J I A i S I 0 N i D
Mix
1973 4
J I F | M | A | M | J | J | A | S | 0 I N
Figure 3-6.—Thermal stratification and mixing In Pickerel Lake. Lines represent the depth
to which the tempearture (Indicated in the circle) prevails. Temperatures are °F.
53
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Pickerel Lake mixed in early August, again distributing bfueigreen algae off the
bottom throughout the entire lake. During August and September, a massive
blue-green algal bloom occurred as the warm weather created favorable en-
vironmental conditions for algalgrowth.
Transparency
Secchi depth is probably the most frequently used parameter in limnology. The
Secchi disk is a 20 cm plastic or metal disk that is either painted entirely white
or divided into alternating black and white quadrants. The disk is lowered into
the water, and the observer measures the depth at which it can no longer be
seen. This depth is recorded and is referred to as the "Secchi transparency," or
Secchi depth, of the lake (see Fig. 3-7).
The assumption is that the greater the Secchi depth, the better the water
quality of the lake. The 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 inorganic suspended solids, and the amount of
organic suspended solids (algae cells). The relationship between the Secchi
transparency and the amount of algal biomass as expressed in chlorophyll a
has been developed for a large number of lakes/Each ecoregion of the country
should develop this relationship independent of the others because turbid
waters might be normal in some regions but unusual in others.
Secchi depth is midway-
r
Disk raised slowly to point
where it reappears
Disk lowered slowly until it
disappears from view
Rgure 3-7.—The Socchl disk Is a simple and extremely useful tool for tracking long-term
trends In lake water quality.
54
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Chemical Parameters
Dissolved Oxygen
These determinations are extremely useful because dissolved oxygen can act
' as an integrator of the health of the lake.
In shallow lakes that mix periodically during the summer, dissolved oxygen
measurements should be made at the same time as temperature determina-
tions. Periods of no mixing when dissolved oxygen in the bottom goes to zero
followed by periods of mixing, can result in the release of phosphorus from the
bottom during anoxia and its eventual redistribution throughout the lake. This
can promote the development of algal blooms.
The deeper lakes that remain stratified during the summer may not require
a high frequency of sampling for dissolved oxygen and temperature to under-
stand their water quality patterns. There is, however, a critical period during the
spring just as a eutrophic lake is beginning to stratify. At this point, weekly
measurement of dissolved oxygen at 1 - or 2-foot intervals is suggested until
the dissolved oxygen concentration approaches zero in the hypplimnion. The
rate of dissolved oxygen depletion can then be calculated, This fate can be
useful in designing aeration systems if this is a chosen management option.
The rate of dissolved oxygen depletion is also another indicator of the severity
of the lake trophic condition. Generally, the more rapid the depletion rate, the
more eutrophic the lake.
Low dissolved oxygen may be the cause of both summer and winter fish-
kills. During summer months, the dissolved oxygen in shallow eutrophic lakes
may be depleted following a rapid algal .die-off. Severe dissolved oxygen
depletions can occur from natural causes, but they can also result from unwise
management; for instance, treating an algal bloom in the entire lake with her-
bicides can drastically reduce the dissolved oxygen and cause a fishkill. Also,
, for lakes that freeze at the surface during the winter months, dissolved oxygen
can be reduced by the end of winter to conditions that cause a fishkill.
PH
An indication of acidity in lake water, the 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. '
Acid rain typically has a pH of 4.0 to 4.5. In contrast, most lakes have a
natural pH of about 6 to 9.
Alkalinity/Acid Neutralizing Capacity
Alkalinity is a measure of the acid neutralizing capacity of water; that is, the
ability of a solution to resist changes in pH by neutralizing acid input. In most
lakes, alkalinity exists through a complex interaction of bicarbonates, car-
bonates, and hydroxides in the water. The higher the alkalinity, the greater the
ability of water to neutralize acids. .
55
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Low alkalinity lakes are not well .buffered and typically are also relatively low
in pH. When alkalinities are less than 20 mg/L, the Gran analysis method
should be used. The Gran method for alkalinity provides information that is
referred to as "acid neutralizing capacity" because it includes alkalinity plus the
additional buffering capability of dissociated organic acids and other com-
pounds.
Nutrients
The nutrients to be sampled in a lake study are generally those (principally
phosphorus and nitrogen) that are critical to plant growth. Phosphorus is often
the key nutrient in determining the quantity of algae in the lake. Chapter 2 ex-
plained the role of plant nutrients and their relative availability in lake systems.
Certain species of algae can fix atmospheric nitrogen and add to a lake's
nitrogen pool if nitrogen is in short supply. For eutrophication studies, total
phosphorus is the single most important nutrient to determine in the incoming
and outgoing streams. Many lake management decisions wjll be made based
on the total phosphorus income to a lake. The modeling efforts (see Chapter 4)
to predict water quality changes as a result of an implementation project are
based on the total phosphorus loadings. Other cherhjcal analyses that are im-
portant are total soluble phosphorus, soluble reactive phosphorus, total Kjel-
dahl nitrogen, nitrate nitrogen, ammonium nitrogen, and total and dissolved
solids. Occasionally, measurements of chloride or potassium are useful in-
dicators of agricultural or urban source problems.
• The total nitrogen (N) to total phosphorus (P) ratio (N:P) in the lake water
can help determine what algae might prevail (e.g., N:P 10 • 1). For example,
nitrogen-fixing btue-green algae might be favored during periods of low
nitrogen content in the lake. Since phosphorus is not a volatile chemical, its
sources are rather' limited. Because of this, controlling phosphorus is usually
the only practical solution to the problems of algal growth in a lake.
Of specific interest is the nutrient load during normal strearnflow and the
nutrient income during storm events. A single, large storm may produce a
nutrient income equal to several months' worth during normal flow. To obtain
nutrient samples during storms, automatic sampling devices that are activated
by rising water .levels in the streams should be installed. The automatic
samplers are made for convenience, since volunteers will probably not go out
to collect samples during a storm, especially when it starts at 3a.m. on Sunday
morning.
The final component of stream work is the coupling of nutrient concentra-
tions in- the stream water to the strearnflow to develop an annual nutrient in-
come to the lake. Once the annual nutrient and water income for the monitored
subbasins within the watershed- have been calculated, they can be extrapo-
lated to the unmonitored subbasins. In the final analysis, the incomes from all
of the subbasins are added together to produce the total surface watershed in-
come to the lake.
Biological Parameters
Biological indicators of eutrophication can be a variety of different organisms,
but the most frequently monitored indicators are algae and macrophytes. An
overabundance of either usually brings numerous complaints from lake users.
56
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Algal Biomass
Biomass determinations are probably the most useful measurement of the
amount of algae, followed by actual identification of species. The biomass
measurement most frequently used is chlorophyll a: In most studies,.an in-
tegrated water sample is collected from the upper portion of the lake (the
photic, or lighted, zone) either by taking water samples from several depths
and mixing them together, or by using a tube that extends through the photic-
zone. Peak chlorophyll a concentrations in an oligotrophic lake may range from
1.5 to 10.5 ng/L, while peak concentrations in a eutrophic lake may range from
10 to 275 pig/L The average summer chlorophyll concentrations are good in-
dicators of the severity of the algal problems in a lake.
Algal identification also can be useful in conjunction with the biomass
measurements. A determination of the major types of algae that compose the
biomass may help to understand lake problems. Blue-green algae are the
most frequent cause of aesthetic problems; they can float at the surface, leave
a paint-like film on the shores, and cause taste and odor problems.
The chlorophyll a concentrations and the relation to the major algal types
during the growing season are illustrated for eutrophic North Twin Lake (Fig. 3-
8), located in Polk County, Wisconsin. The period of greatest algal problems
can be noted by the higher chlorophyll a concentrations from the end of July
through September. The exact kinds of algae that contribute to the higher
biomass are displayed in the kite diagrams of algal succession. Anabaena, a
blue-green alga that often forms noxious scum at the surface of the lake, is
present during the August bloom. Lyngbya, another troublesome blue-green
alga, was dominant during September. The chlorophyll a concentrations
detailed the severity of the algal problem, and the algal identification allowed
for the recognition of the algal species that dominated during the problem
period.
Macrophyte Biomass and Locations
Aquatic macrophyte communities range from completely submerged stands of
large algae (for example, Chara or Cladophora) to stands of rooted plants with
floating leaves (water lilies). Macrophyte densities vary seasonally between
lakes in an area and among regions. In a northern Wisconsin lake, the average
weight of macrophytes might be several hundred pounds per acre, while in
Florida several tons per acre are common. Densities also vary within a lake.
Eutrophic lakes can have very high quantities of plants as can lakes located in
regions with long growing seasons, warm waters, or other favorable condi-
tions.
Macrophytes are usually surveyed once or twice during the growing
season. Several tasks are normally accomplished during a macrophyte survey.
The first is mapping the location and extent of the major community types:
emergents, floating leaves, and submergent plants (see Biology of Macro-
phytes in Chapter 6). The abundance could be described as follows: A = abun-
dant, B = common, S = sparse. This information should be sketched on a
hydrographic map to show, distribution of the major communities. Figure 3-9 is
an example from Pike Lake (Polk County, Wisconsin) that shows the distribu-
tion patterns of the major macrophyte communities during August when plant
density, species identification frequency, and depth of growth should be deter-
mined. .
Chlorophyll a: A
type of chlorophyll
present in all types
of algae, sometimes
in direct proportion
to the biomass of
algae.
Hydrographic map:
A map showing the
location of areas or
objects within a lake.
57
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40
CO ' •
1 30
i*
1" 20
Q.
O
6
6 1°
'•
1
.ill ll
hi
ll
M
4000 '
cells/ml
A S 0
(BG) =
BLUE-GREEN ALGAE
Anabaena
(BG)
2000
cells/ml
200 r
colonies/ml |_
Oscillatoria
(BG)
Lyngbya
(BG) '
Fragilaria
(DIATOM)
Melosira
(DIATOM)
Microcystis
(BG)
Figure 3-8.—The chlorophyll a concentrations and the major algal types during the growing
season fo the eutrophlc North Twin Lake. The period of greatest algal problems can be
noted by the higher chlorophyll a concentrations at the end of July through September. The
exact kinds of algae that contribute to the higher blomass Is displayed In the kite diagrams
of algal succession.
The assembled information on macrophytes is useful in deciding where to
concentrate macrophyte control efforts such as harvesting or dredging and for
predicting the depth to which plants might grow if the water clarity were im-
proved (see Chapter 6).
58
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' Pike Lake
August 14, 1980
Ceratophyllum ...
Utricularia — Potamogeton
Potamogeton — Myriophyllum— Utricularia
Ceratophyllum — Myriophyllum :
Ceratophyllum — Potamogeton — Myriophyllum
Ceratophyllum — Potamogeton —Vallisneria
Figure 3-9.—Pike Lake distribution patterns of the major macrophyte communities during
August. Depth contours are given In meters.
Fish Survey
*
A survey of the fish community can provide useful information on the species
present, the size distribution of those fish species, and the relative availability
of fish prey to the larger fish predators (e.g., the game fish species, see Chap-
ter 2). If poor fishing has been identified as a lake problem, then a survey of
the fish community is needed to document existing conditions. A fish survey
can be conducted by seining if the lake is sufficiently small and shallow. How-
ever, larger lakes are usually sampled with gill nets, by electroshocking, or by
rotenone poisoning. ,
A fish survey may reveal that a desired game fish species does not even
live in the lake. Lake conditions may not be suitable for its habitat or survival;
conditions could have changed to result in its elimination; or the population
could have been wiped out by a combination of overfishing and poor reproduc-
tion. Alternatively, the desired species may be present but in very low numbers
because of poor reproduction resulting from a lack of suitable habitat or from
intense competition for'food with another predator. A game fish population may
be large, but in poor condition or stunted in size because of a lack of suitable
prey. Appropriate fishery management practices cart be applied to alleviate
most of these problems, 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 results, and to, suggest a fishery management strategy.
Use of Trophic State Indices
A variety of indices are available to rate measured in-lake variables on a scale
so that the severity of lake problems can be compared to other lakes in the
area. This provides a quantitative means of assessing lake changes after
protection and restoration practices have been implemented (Carlson, 1977;
59
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Kratzer and Brezonik, 1981; Walker, 1984). These lake indices, often referred
to as "trophic state indices," attempt to simplify complicated environmental
measurements. As Reckhow (1979) has pointed out, an index is a summary
statistic that is used because its convenience outweighs the disadvantage of
information lost in summarization.
The basis for the trophic state index concept .is that, in many lakes, the de-
gree of eutrophication is believed to be related largely to jncreased nutrient
concentrations in the lake. Often phosphorus is the nutrient of concern. An in-
crease in lake phosphorus concentration is expected to' cause an increase in
the amount of lake algae (see Chapter 2 to review this concept) as measured
by chlorophyll a. Simultaneously, there would likely be an associated decrease
in water transparency as measured by a Secchi disk and an increase in fish
standing crop. .
The Carlson (1977) Trophic State Index (TSI) is the most widely used (see
Chapter 4). It was developed to compare determinations of chlorophyll a, Sec-
chi transparency, and total phosphorus concentration. Higher index numbers
indicate a degree of eutrophy while low numbers indicate a degree of
oligotrophy (low nutrient and algal concentrations and high transparency). The
index was scaled so that a TSI = 0 represents a Secchi transparency of 64
meters. Each halving of transparency represents an increase of 10 TSI units. A
TSI of 50, thus, represents a transparency of 2 meters, the approximate
demarcation between oligotrophic and eutrophic lakes.
Suppose that a lake had a transparency index of 60 prior to implementation
of lake restoration. If two years later, the index is 40, this would be a quantita-
tive estimate of the degree of improvement. A TSI of 40 might be common to
undeveloped lakes in the area; this might indicate that the lake has improved
about as far as it can. Significant upward movement of the index in .later years
would indicate a return of the lake to its previous condition. The index, there-
fore, is a useful tool for assessing the lake's current condition and for monitor-
ing change overtime.
The Carlson TSI works well in north temperate lakes that are phosphorus-
limited but poorly in lakes that are turbid from erosion or in lakes With extensive
weed problems. Figure 3-10 is an example of TSI plots for a north temperate
lake of relatively poor water quality; Figure 3-11 illustrates a more complex
situation when it is necessary to determine why parameters do not agree as
expected. By scanning the TSI plots, the lake manager can begin to under-
stand the patterns in a particular lake and appreciate the seasonal variations
without having to analyze phytoplankton and phosphorus concentrations and
place trophic interpretations on them. .
The TSI values calculated for chlorophyll a, for example, may not be similar
to simultaneous calculations of TSI from Secchi disk or total phosphorus meas-
urements. Understanding this particular situation requires the consultant to ex-
amine the database in greater detail. In this case, an explanation might be the
presence of suspended materials that reduce light attenuation and, therefore,
algal productivity. An abundant population of large zooplankton might be ac-
tively feeding upon the algae and reducing their biomass. In such cases, the
TSI plots would be valuable because they allow a professional to assess the
situation and the possible need for additional information to make decisions.
Other indices have been developed that are more appropriate for the
various major lake ecoregions in the country. Walker (1984) has developed
such an index for reservoirs, and Brezonik (1984) has developed an index that
more specifically fits the needs of Florida lakes and includes situations where
nitrogen rather than phosphorus may be limiting algal growth. Porcella et al.
(1979) have included a term in their Lake Evaluation Index that represents the
amount of lake surface covered by macrophytes.
60
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— A — — Chlorophyll-^
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Figure 3-10.—A TSI plot for a north temperate lake that Is considered to have poor water
quality. , .
Problem Definition
Putting the Pieces of the Puzzle
Together
Identifying lake problems is not that difficult; identifying the source of a par-
ticular problem takes a little more effort. The in-lake and watershed measure-
ments necessary to identify the severity of a problem and track down the sour-
ces that cause various problems have been discussed. The final step is to use
the information to make lake management decisions.The best way to illustrate
the .importance of measuring the severity of the lake problem and identifying
the sdurces is to present an example. -
Mirror Lake
Mirror Lake is a small urban lake located within the city limits of Waupaca, Wis-
consin. The lake has a surface area of 1.2.5 acres and a maximum d.epth of 43
feet.and had experienced repeated blue-green algal blooms and winter fish-
kills. Since the city had an interest in restoring Mirror Lake, a diagnostic study
was designed to determine the annual incomes of water and total phosphorus
and to examine the condition of the lake's water quality.
61
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80
70
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A TSI (Chlorophyll-a)
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Figure 3-11.—A TSI plot that adds more complexity to the Interpretation. The TSI (chl. a)
plot does not agree with either the TSI(SD) or the TSIfTP) plots. Understanding this par-
ticular situation requires the lake manager to examine the data base In much greater detail.
Mirror Lake is a seepage lake with no permanent inflowing streams from the
watershed. If it had been a drainage lake, then considerable attention would
have been paid to land uses and streamflows to identify those areas of the
watershed most responsible for the silt and nutrient loads causing the problem.
Water and nutrient incomes were studied during 1972 and 1973; Table 3-4
lists the results. Storm sewers from the city contributed more than 50 percent
of the phosphorus income to Mirror Lake and were the obvious targets for lake
protection efforts. The study demonstrated that the greatest periods of phos-
phorus income were during.spring showers and intense late summer rainfalls.
Total phosphorus concentration in the lake averaged 90 ng phos-
phorus/liter, a very high value. The Carlson Trophic State index number for
total phosphorus concentrations was 69, a value expected for an extremely
eutrophic lake. Measurements of phosphorus throughout the water column
revealed extremely high concentrations in the hypolimnion, particularly near
62
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the sediments. Experiments were then, conducted to determine whether this
phosphorus came from the sediments. The results revealed a high release rate
or internal phosphorus loading from the sediments.
The algae in the lake during the summer were unlike those found in many
other eutrophic lakes. The spring and fall months were characterized by mas-
sive blooms of a blue-green algae called Oscillatoria agardhii, but the summer
season saw this species confined to the metalimnion (see Chapter 2), while
the upper waters were dominated by green algae.
It became obvious that the year-to-year increase in the quantity of algae of
Mirror Lake was a response to stormwater inputs. A sediment core was taken,
dated with the Lead-210 techniques, and analyzed for the presence of par-
ticular types of chlorophyll pigments common in Oscillatoria. The first bloom of
algae, as recorded by pigments in the sediments, occurred in the early 1940s,
just a few years after storm drainage was diverted to the lake.
The diagnostic study demonstrated that very low dissolved oxygen in Mirror
Lake during the winter caused winter fishkills. An analysis of the data revealed
that this problem was due to poor lake mixing during fall months before ice
developed (see Chapter 2 for a discussion of expected thermal histories of
lakes). This meant thatjhe lake had very low dissolved oxygen in it when the
ice formed on the water's surface and eliminated oxygen exchange with the at-
mosphere. The data from the diagnostic study were used to determine ap-
propriate lake protection:and restoration strategies.
. In 1976, storm sewer diversion reduced the phosphorus income to the lake
by 50 to 60 percent. This step was taken after a historical analysis of lake sedi-
ments showed a relationship between the onset of algal blooms and the begin-
ning of stormwater discharge to the lake. Lake users expected the lake to im-
prove immediately. As shown in Figure.3-12, total phosphorus concentration in
the Mirror Lake in 1977 and part of 1978 was very similar to the prediversion
average of .90 ng phosphorus per liter. This result demonstrated that storrn
sewer diversion was a necessary step to lake protection, but insufficient for
lake restoration. The hiQh internal phosphorus release was recycling phos-
phorus stored in the sediments from the 35 years of storm drainage. These
phosphorus-rich waters were probably transported from the bottom to the
upper waters during summer storm mixing, which helped maintain high phos-
phorus levels in the water column.
This problem was identified because monitoring had continued after storm
sewer diversions. This post-diversion monitoring was an integral part of diag-
nosis and implementation (see Chapters).
Aluminum sulfate was applied to Mirror Lake sediments in May 1978 to "in-
activate" this phosphorus release (see Chapter 6 for a more detailed discus-
sion of this procedure). As shown in Figure 3-12, total phosphorus fell to about
20 ng phosphorus per liter and has remained at that low level for several
years. This action produced a total phosphorus TSI of about 47, a value found
in lakes that are considered to be borderline eutrophic. A lake with this total
phosphorus concentration would be expected to have fewer problems with'
algae and sharply improved transparency. This is what happened. Oscillatoria
agardhii was not present in Mirror Lake by 1980.
The problem with low dissolved oxygen under the ice was solved by using
an artificial circulation device (see Chapter 6) in the fall to thoroughly mix the
lake. Figure 3-13 shows the success of. the treatment. The threat of a winter
fishkill was ended.
63
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64
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Mirror Lake
Dissolved oxygen (mg/L)
D JFMAMJ JASON
DJ FM.AMJ JASON
DJ FM A M J J • A SON
Figure 3-13.— Oxygon concentrations In Mirror Lake before and after aeration show that
both the duration and severity of anoxia decreased. Oxygen concentrations are Indicated
by the numbers on the lines (Isopleths). 0 indicates no oxygen.
This case history represents a real and highly successful use of the diag-
nosis-feasibility-implementation approach to, lake protection and restoration.
The city and its consultants looked for the causes of the problem. The con-
tinued wasting of money on temporarily effective treatments was replaced with
expenditures directed toward a long-term solution. Had the obvious just been
65
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done (stormwater- diversion only), it would have taken years to flush out
nutrients from Mirror Lake before it came to a new average total phosphorus
concentration. Instead, the consultants identified a second source of phos-
phorus" and treated that as well. The lesson here is that lake management
proceeds from step-by-step approaches that are based upon a knowledge of
both the watershed and the-lake and are directed at the causes, of the
problems. Effective lake management plans (see Chapters 7, 8, and 9) result
from the integration of watershed management practices (see Chapter 5) and
in-lake restoration procedures (see Chapter 6).
APPENDIX3-A
Democratic Procedures to
Obtain Consensus on Priority
Uses for a Lake
Nominal Group Process
The nominal group process is an alternative to the standard group meeting
procedure. In a typical group meeting, a decision is made through the following
sequence: a motion, discussion, and a vote. This standard procedure is
frustrating to most people because they feel intimidated about speaking up in a
group setting or because discussion is monopolized by a few dominant per-
sonalities.
The nominal group process is especially effective at soliciting concerns or
setting priorities. It can also be used to solicit ideas for activities or projects.
Thus, the nominal group process could be used to prioritize uses, enumerate
and prioritize perceived problems, or prioritize projects for a lake organization.
The process has many variations. In its simplest form, each participant is
first asked to write down a list of issues. The moderator than asks each person
to volunteer one issue from that person's list. The moderator proceeds around
the group until all issues are transferred from individual written lists to sheets of
paper hung in view of the group. During this time, there is no discussion or
debate on the appropriateness of anyone's suggestion. Each participant
decides whether his or her issues are already listed on the sheet. The
moderator proceeds around the group until no one has any morejssues to con-
tribute.
After all issues are listed, the group debates whether certain issues should
be combined. The discussion on combining issues usually leads into a general
discussion, led by the person who suggested the issue, that is designed to help
others understand it more fully. The moderator must be forceful in keeping the
66'
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discussion focused on understanding each issue and eliminating duplication if
the "authors" of those issues agree. The discussion is not allowed to become a
debate on the merits of the issue.
Following the discussion, the moderator allows each person to select a
limited number of issues to "save" by placing a marK. or sticker next to those is-
sues. (The physical act of getting up and placing marks provides a nice,
refreshing break in the process.) The 3 to 10 issues with the largest number of
votes are placed by the moderator,into a priority pool. Participants then rank
those issues.
The nominal group method is designed to allow equal participation by all
members of the group. Dominant personalities are neutralized by the proce-
dure. If a group exceeds 15 people, it is advisable to split the group into
smaller subgroups and proceed until each subgroup has identified its priority
pool. The priority pools are then combined, and the entire group ranks the is-
sues in the combined pool.
In larger lakeshore communities, direct participation by ail property owners
and local, lake users may not be feasible. Under such circumstances a task
force or advisory committee might serve to represent the community and
report to a city council or county board. The nominal group process may still be
a useful procedure for the task force or advisory committee, itself, to use.
In addition to identifying issues, the participants leave the process with a
much higher sense of ownership than they do after participating in a standard
meeting. After the nominal group experience, they identify with the priorities
because they actively help to select them.
Delphi Process
The Delphi technique is premised on incomplete knowledge and an inherent
bias by any one expert (or citizen). Therefore, a panel of experts is expected to
produce a more complete range of issues or solutions and a more balanced
prioritization than a single expert.
This procedure is useful in setting research priorities, summarizing current
knowledge,, and making policy recommendations for public bodies. For in-
stance, it could be used to design a management plan for a new reservoir.
The first stage of the process is a solicitation of the full range of issues,
ideas, and concerns associated with the topic. The experts at a meeting or
through correspondence simply provide a laundry list of all items that might be
appropriate.
In the second stage, the list developed in Phase I is provided to the same
experts for a ranking on some specified criterion of importance. The results of
Phase II are. communicated to the organization that initiated the effort. Addi-
tional phases can be used to obtain greater specificity regarding the highest-
ranked items.
While this procedure is too complicated and expensive for most lakeshore
communities, it is often a good idea for lake organizations to get a second
opinion oh major recommendations they receive from a consultant or agency
employee.
67
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Chapter 4
PREDICTING LAKE
WATER QUALITY
Uses of Models
Mathematical models can be useful both in diagnosing lake problems and in
evaluating alternative solutions. They represent the cause-effect relationships
(that control lake water quality in quantitative terms. Model formulas are derived
from scientific theories and from observations of the processes and responses in
real lakes. There are two basic ways in which models can be employed in lake
studies:
1. DIAGNOSTIC MODE: What is going on In the lake? Models provide a
frame of reference for interpreting lake and watershed monitoring data.
They tell the user what to expect to find in a lake with a given set of mor-
phometric, hydrologic, and watershed characteristics. These expectations
are not always met, however. Differences between measured and predicted
conditions contain information on the unique features of the lake under
study. They help clarify important cause and effect relationships.
2. PREDICTIVE MODE: What will happen to the lake if we take certain
actions? Models can be used to predict how lake water quality conditions
will change in response to changes in nutrient inputs or other controlling
factors. For practical reasons, "it is usually infeasible to predict lake respon-
ses based on full-scale experimentation with the lake and its watershed. In-
stead, mathematical models permit experiments to be performed on paper
or on computer.
Examples of questions that might be addressed through lake modeling include
• What did the lake look like before anyone arrived?
• What level of nutrient loading can the lake tolerate before it develops
algae problems?
• How will future watershed development plans affect the lake's water
quality?
Morphometry:
Relating to a lake's
physical structure (e.g.,
depth, shoreline length).
69
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'- • What are the most important sources of the lake's problems?
•• What reduction in nutrient loading is needed to eliminate nuisance .
algal blooms in the lake?
•• How long will it take for lake water quality to improve once watershed
or point source controls are in place?
• What is the expected range of water quality conditions over several
years (given a year's worth of monitoring data collected in the lake
and its watershed)?
• What is the probability that restoration efforts will be successful (given
a water quality management goal such as a target level of lake
phosphorus, chlorophyll a, or transparency and an array of feasible
control techniques)?
• Are proposed lake management goals realistic?
Models are not the only means of addressing these questions, and they do
have limitations. For example, modeling is feasible only for evaluating those
types of problems that are understood weir enough to be expressed in concise,
quantitative terms. In some situations, modeling may be infeasible or unneces-
sary. Why make a lake study more complicated than it has to be?
Models are not monoliths. They are rather frail tools used by lake manage-
ment consultants in developing their professional opinions .and recommenda-
tions. The consultant should decide which models (if any) are Jippropriate, what
supporting data should be collected, how the models should be implemented, and
how the model's results should be interpreted. Consider the following analogy:
HOME ADDITION LAKE STUDY
Carpenter Consultant
Tools Modeling Techniques
Raw Materials Monitoring Data
Different carpenters may prefer certain brands of tools to others: The selection
of appropriate tools to accomplish a given job is an important, but not the only fac-
tor determining the success or failure of a project. In home building, the quality of
the addition depends less upon which tools are used than upon how they are
used. The owner hires the carpenter, not the tools. This premise also applies to
' hiring a lake management consultant. Obviously, the quantity and quality of raw
materials are every bit as important as the tools used on the job. The raw
materials required for applying a model to a lake are monitoring data and other
baseline information developed under diagnostic studies (see Chapter 3).
For ease in explaining modeling concepts, English units are used in the ex-
amples in this chapter. Lake modeling is far less awkward, however, when metric
' units are used.
Phosphorus loading models, which relate the phosphorus supply to algal
growth in lakes, are the primary focus of this chapter. However, it should be noted
that other models can be used to relate the relative availability of nutrients and
lake morphometry to fish production (e.g.,, Ryder et al. 1974; Ryder, 1982;
Jenkins, 1982) and to relate chlorophyll concentrations to, sportfish harvest
(Oglesby, 1977; Jones and Hoyer, 1982) in lakes and reservoirs. As explained in
Chapter 2, the basic concept underlying these models is that nutrient availability,
algal production, and fish production are strongly interrelated (see Fig. 2-10).
Therefore, increasing or decreasing the nutrient loading to a lake will generally
result in a corresponding increase or decrease in nutrient availability, algal
growth, and ffsh production.
70
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Eutrophication Model Framework
Phosphorus loading models are" frequently used to evaluate eutrophication
problems related to algae. These models link phosphorus loading to the average
total phosphorus concentration in the lake water and to other indicators of water
quality that are related to algal growth, such as chlorophyll and transparency (Fig.
4-1). Lake responses to phosphorus loading depend upon physical and
hydrologic characteristics. Therefore, these models consider .lake volume,
average depth, flushing rate, and other characteristics when predicting lake
responses to a given phosphorus load.
While the terms and equations involved may seem foreign, the three underly-
ing concepts ar,e simple.
1. Lake algal growth is limited by the supply of phosphorus.
2. Increasing or decreasing the mass of phosphorus discharged into the lake
over an annual or seasonal time scale will increase or decrease the
average concentrations of phosphorus and algae in the lake.
3. A lake's capacity to handle phosphorus loadings without experiencing
nuisance algal blooms increases with volume, depth, and flushing rate.
In other words, the lake's condition depends upon how much phosphorus it
receives from both internal and external sources. A large, deep lake with a high
flow will be able to handle a much greater phosphorus load without noticeable
deterioration than a small, shallow, or stagnant lake. Models summarize these
relationships in mathematical terms, based upon observed water quality respon-
ses of large numbers of lakes and reservoirs.
Algal growth in these models is usually expressed in terms of mean, growing-
season chlorophyll in the epilimnion concentrations. As discussed in Chapter 3,
phosphorus, chlorophyll a, and transparency help to define trophic state, a vague
concept used to characterize lake, condition. Other variables related to algal
productivity^ such as hypolimnetic oxygen-depletion rate, seasonal maximum
chlorophyll a, bloom frequency, or organic carbon, may also be considered in
phosphorus loading models.
These methods cannot yet be used to predict aquatic weed densities, which
generally depend more upon lake depth, the quantity and quality of lake bottom
sediment, and light penetration than upon the loading of nutrients entering the
lake from its watershed, " . ,
Eutrophication models rely heavily on the lake phosphorus budget, which is
simply an itemized accounting of the inputs and outputs of phosphorus to and
from the lake water column over a year or a growing season. Although budgets
can be constructed for other pollutants that cause lake problems (nitrogen, silt,
organic matter, bacteria, or toxics, for example) phosphorus budgets are used
more frequently.
A phosphorus budget provides a means to evaluate and rank phosphorus
sources that may contribute to an algal problem. The basic concept and mathe-
matics are relatively simple, although the estimation of individual budget items
often requires considerable time, monitoring data, and expertise.
Basic concepts involved in constructing phosphorus budgets and applying
eutrophication models are described and illustrated in later sections of this chap-
ter. In some situations, particularly in reservoirs, algal,growth may be controlled
by factors other than phosphorus, such as nitrogen, light, or flushing rate (Walker,
1985). Appropriate models for these situations are more complex than those dis-
cussed in the next section, although the general concepts and approaches are
similar. -
71
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Variability
Eutrophication models are geared to predicting average water quality condi-
tions over a growing season or year. Unfortunately, this often gives the mis-
taken impression that water quality is fixed and does not vary in different areas
or through time within a given lake. This is not the case. Averaging is typically
done over three dimensions: - " .-
1. DEPTH: The top, mixed layer is the part of the water column that is
generally averaged. Vertical variations within the mixed layer are usually
small.
2. SAMPLING STATION: Stations might be located in different places of
the lake. In a small, round lake, the variations among these stations will
tend to be insignificant; therefore, one location is usually adequate. In a
large lake with several embayments,,in a long, narrow reservoir, or in a
complex reservoir with several tributary arms, however, water quality
may vary significantly (from oligotrophic to hypereutrophic) from station
to station. In such situations, a measurement for the "average water
quality" may be meaningless; it may be more appropriate to divide the
lake or reservoir into segments for modeling purposes since outflow from
one segment serves as inflow to the next. .
3. A SEASON: Phosphorus, transparency, and especially chlorophyll a
concentrations usually vary significantly at a given station from one sam-
pling date to the next during the growing season. It is not unusual, for ex-
ample, for the maximum chlorophyll a concentration to exceed two to
three times the seasonal average. Because the input data themselves
represent values within a range of actual conditions, model outputs also
should be considered to represent answers within a range. Thus, model
calculations are generally reported as having a certain "percent conr
fidence" to indicate the likelihood that the answer is correct within a
given range. , ,
In addition, since chlorophyll a, phosphorus, and transparency vary during
the season to begin with, a slight improvement or deterioration in these water
quality characteristics is difficult to perceive. A model prediction that conditions
would improve slightly, therefore, is not likely to represent a noticeable change
in the lake. When the change becomes comparable to normal variations, it is
easier to observe an improvement or deterioration.
Because of these variabilities, it is more realistic to consider measured or
modeled water quality as a range of values rather than as a "point." If a con-
sultant says that a lake has a mean chlorophyll a concentration of 10 ppb
(parts per billion), for example, the actual mean may be 5 or 20 ppb, depending
on monitoring frequency and lake variability. Perhaps more important, even if
the seasonal mean is 10 ppb, 90 percent of the samples will be in the 2 to 24
ppb range for a lake with typical seasonal variability.
In a given watershed and lake, year-to-year variations in average water
quality may be significant because of fluctuations in climatologic factors, par-
, ticularly streamflows and factors controlling thermal stratification. Monitoring
programs extending for a period of at least three years are often recommended
to characterize this year-to-year variability and to provide an adequate basis
for lake diagnosis and modeling.
73
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Another source'of variability.is model error. Statistical analyses of data from
large numbers of lakes and reservoirs indicate that phosphorus loading models
generally predict average lake responses to within a range of one to two times
the average. Differences between observed and predicted water quality, in
part, reflect variability in the data (loading estimates and observed lake respon-
ses) and inherent model limitations. Differences between observed (directly
measured) and predicted (modeled) values may contain useful information for
diagnostic purposes, however. Model projections of future conditions resulting
from a change in phosphorus loading are more reliable when they are ex-
pressed in relative terms (percent change from existing conditions). A good
lake and watershed monitoring program can reduce the risk of significant
model errors, which may lead to false conclusions and poor management
decisions.
Loading Concept
Loadings most accurately express the relative impacts of various watershed
sources on lake water quality. For example, a stream with a high phosphorus
concentration will not necessarily be an important source to the lake, because
the stream may have a very low flow and, therefore, contribute a relatively low
annual loading.
Because lakes store nutrients in their water columns and bottom sediments,
water quality responses are related to the total nutrient loading that occurs
over a year or growing season. For this reason, water and phosphorus budgets
are generally calculated on an annual or seasonal basis. Water and phos-
phorus residence times in the water column determine whether seasonal or an-
nual budgets are appropriate for evaluation.of a given lake.
Phosphorus loading concepts can be illustrated with the following analogy:
GROCERY BILL
Item
Quantity
Unit Cost
Cost of Item
Total Cost of All Items
PHOSPHORUS LOADING
Source
Flow
Concentration
Loading From Source
Total Loading From All Sources
The cost of a given item is determined by the quantity purchased and the
unit cost. The total cost of all items purchased determines the impact on fi-
nances (lake water quality). Funds (lake capacity to handle phosphorus load-
ing without water quality impairment) are limited. Therefore, intelligent shop-
ping (managing the watershed and other phosphorus sources) is required to
protect finances (lake water quality).
Loadings change in response to season, storm events, upstream point
sources, and land use changes. For example, converting an acre of forest into
urban land usually increases the loading of phosphorus by a factor of 5 to 20, a
result of increases in both water flow (runoff from impervious surfaces) and
nutrient concentration (phosphorus deposition and washoff from impervious
surfaces). An evaluation of loadings provides a basis for projecting lake
responses to changes, in land use or other factors.
74
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The grocery bill analogy breaks down in at least one important respect:
shoppers can read the unit costs before they purchase the food. To estimate
phosphorus loading from a given source, both flow and concentration must be
quantified over annual and seasonal periods, this is difficult because both flow
and concentration data vary widely in response to season, storm events, and
other random factors. Flow should be monitored continuously in major
streams. Concentration is usually sampled periodically (weekly, monthly) and
preferably supplemented with samples taken during storms. This is why good
lake and watershed studies cost so much. Particularly in small streams prone
to flash flooding, a very high percentage of the annual loading may occur
during short, intense storms. If these events are not sampled, it will be relative-
ly difficult to develop reliable loading estimates. -
Because of these factors, loading estimates.for each source should be con-
sidered with a degree of skepticism. These are not fixed quantities but ranges.
Depending upon monitoring intensity and calculation methods, an annual load-
ing estimate for a given stream could be off by a factor of 2 or more. Where ap-
propriate, monitoring intensity can be increased to provide better data for,
quantifying loadings, particularly in streams that are thought to be major-con-
tributors.
Water Budget
The first step in lake modeling is to establish a water budget. Flows carry pol-
lutants into and, out of lakes, and analyses of lake eutrophication and most
other water quality problems cannot be conducted without a quantitative un-
derstanding of lake hydrology. The basic water balance equation considers the
following terms, typically in units of acre-feet per year:
INFLOW + PRECIPITATION = OUTFLOW + EVAPORATION + CHANGE IN STORAGE
Water budget concepts are illustrated in Figure 4-2.
*• ' .
LAKE WATER BUDGET
PRECIPITATION. EVAPORATION ,
TRIBUTARY INFLOWS —. ' I ' t /"** WITHDRAWALS
N^j . |/
DIRECT RUNOFF \ CHANGE IN STORAGE T ^^^. SURFACE OUTFLOW
POINT-SOURCE
DISCHARGES
GROUNDWATER INFLOWS -, ^ -^ ^-»- GROUNDWATER OUTFLOWS
Figure 4-2.—Water budget schematic.
The data for the INFLOW and OUTFLOW should be evaluated over annual
or seasonal periods. Inflows may include tributary streams, point source dis-
charges, runoff from shoreline areas, 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 gaged directly. Indirect estimation procedures, (for example, runoff coeffi-
cients) can be used to quantify smaller streams. PRECIPITATION and
EVAPORATION can be derived from regional climatologic data. The CHANGE
75
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IN STORAGE accounts for changes in surface elevation over the study period,
which is sometimes significant in reservoirs. This change is positive if lake
volume increases over the study period, negative otherwise.
Once the flow terms have been estimated and tabulated, the water balance
should be checked by comparing the total inflows with total outflows. Major dis-
crepancies may indicate an omission or estimation error in an important source
of inflow or outflow (such as unknown or poorly defined streamflow or
groundwater flow). In seepage lakes, it is relatively difficult to establish water
balances because of the problems and expense of monitoring groundwater
flows. In any event, significant errors in the water balance may indicate a need
for further study of lake hydrology.
To provide a complete accounting of the watershed, drainage areas should
also balance (that is, the sum of the tributary drainage areas plus the lake sur-
face area should equal the drainage area at the lake outlet).
Phosphorus Budget
The lake phosphorus budget (Fig.4-3) provides the cornerstone for evaluating
many eutrophication problems. The following terms are evaluated and typically
expressed in units of pounds per year:
INFLOW LOADING = OUTFLOW LOADING + NET SEDIMENTATION + CHANGE IN STORAGE
This equation summarizes fundamental cause and effect relationships link-
ing watersheds, lake processes, and water quality responses.
LAKE PHOSPHORUS BUDGET
PITA
ISTF
I
PRECIPITATION
&DUSTFALL MIGRANT WATERFOWL
TRIBUTARY INFLOWS . ' /-*• WITHDRAWALS
DIRECT RUNOFF ^ ' CHANGE IN STORAGE f ^^-*- SURFACE OUTFLOW
POINT-SOURCE
.DISCHARGES
GROUNDWATER INFLOWS ____ *" """*-— -i-—-^ ' ^ — »• GROUNOWATER OUTFLOWS
& SHORELINE SEPTIC TANKS .
NET SEDIMENTATION
Figure 4-3. — Phosphorus budget schematic.
The INFLOW LOADING term indicates the sum of all external sources of
phosphorus to the lake, which may include tributary inflows, point sources dis-
charging directly to the lake, precipitation and dustfall, leachate from shoreline
septic tanks, other groundwater inputs, runoff from shoreline areas, and con-
tributions from migrant waterfowl. Estimation of individual loading terms is the
most important and generally most expensive step in the modeling process. In-
vestments in intensive monitoring programs to define and quantify major load-
ing sources usually pay off in terms of the quality and reliability of project
results. Monitoring .of the lake itself is usually conducted during the same
period so that loadings can be related to lake responses.
Stream loadings, usually the largest sources, are estimated from stream-
flow and phosphorus concentrations monitored over at least an annual period.
76
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To provide adequate data for loading calculations, major tributaries should be .
sampled just above the lake over a range of seasons and flow regimes (includ-
ing storm events). In large watersheds, it may be appropriate to sample at
several upstream locations so that contributions from individual point and non-
point sources can be quantified. Special studies may be required to .estimate
groundwater input terms (for example, grouhdwater sampling and flow model-
ing, shoreline septic tank inventories). Loadings in runoff from shoreline areas
and from relatively small, unsampled tributaries can be estimated indirectly, as
discussed in the following paragraph. Loadings in precipitation and dustfall,
usually relatively small, can be estimated from values obtained from the litera-
ture or regional sampling data. •
In many cases, indirect estimates of loading from a given stream or area
can be derived from information on watershed characteristics. This method is
based upon the concept that two watersheds in the same region and with
similar land use patterns and geology will tend to contribute the same loading
of phosphorus per unit area. This permits extrapolation of data from one or
more monitored watersheds to others. EXPORT COEFFICIENTS (pounds of
.phosphorus per acre a year) have been compiled for various land uses .and
regions (see Chapter 2, Table 2-1). The applicability of this method depends
largely upon the quantity and quality of regional export coefficient data for the
• land uses and watersheds under study. This approach is much less costly than
direct monitoring but generally less reliable. It is frequently used in preliminary
studies (to get a rough handle on the lake nutrient budget before designing and
conducting intensive monitoring programs) and for estimating loadings from
small watersheds whose contributions to the lake's total phosphorus budget
are relatively insignificant.
The term OUTFLOW LOADING relates to phosphorus leaving the lake in
surface outlet(s); withdrawals for water supply, irrigation, or other purposes;
and groundwater seepage. These parameters are usually estimated by direct
measurements of flow and concentration (as described previously for stream
loadings). If lake outflow is dominated by groundwater seepage, it will be dif-
ficult to determine the outflow loading term directly.
The term NET SEDIMENTATION defines the amount of phosphorus ac-
cumulated or retained in lake bottom sediments. It reflects the net result of all
physical, chemical, and biological processes causing vertical transfer of phos-
phorus between the water column and lake bottom (as described in Chapter
2). For a given loading, lake water quality will generally improve as the mag-
nitude of sedimentation increases because higher sedimentation leaves less
phosphorus behind in the water column to stimulate algal growth. Because
several complex processes are involved that vary spatially and seasonally
within a given lake, it is generally infeasible to measure net sedimentation
directly. Accordingly, this term is usually calculated by obtaining the difference
from the other terms or estimated by using empirical models of the type dis-
cussed in Lake Response Models.
The CHANGE IN STORAGE term accounts for changes in the total mass
of phosphorus stored in the lake water column between the beginning and end
of the study period, Such, changes would reflect changes.in lake volume,
average phosphorus concentration, or both. This term is positive if the phos-
phorus mass increases over the study period, negative otherwise.
As formulated previously, the water and phosphorus budgets provide im-
portant descriptive information on factors influencing lake eutrophication. A
useful format for presenting results of budget calculations, illustrated in Table
4-1, is based on data from Lake Morey, Vermont. The table provides a com-
plete accounting of drainage areas, flows, and loadings. The relative impor-
77
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Figure 4-4.—Relative importance of various sources of water and total phosphorus for
Lake Moray, Vermont
79
-------
contributions from various watersheds of different sizes. Often these values
are sensitive to land uses, point sources, or geologic factors. For example, the
relatively high export value for Pine Brook (.47 versus a range of .04-.21
Ibs/acre-year for the other watersheds) reflects erodible soils. High export
values for the Aloha Camp and Bonnie Oaks brooks reflect inputs from camp
sewage treatment systems. .
Comparing the magnitudes of the individual loading terms provides a basis
for ranking sources and identifying possible candidates for watershed manage-
ment or point source control techniques. For example, the Lake Morey phos-
phorus budget clearly indicates that sewering of shoreline areas would not be
an effective way to reduce lake eutrophication because septic tanks currently
account for less than 1 percent of the total loading.
If the net sedimentation term is unusually low (or negative) for a lake of trie
type being studied, it may indicate that bottom sediments are releasing sig-
nificant quantities of phosphorus into the water column and thus, that an in-
lake restoration technique such as sediment phosphorus inactivation (see
Chapter 6) may be appropriate for lake restoration.
Lake Response Models
Having characterized water and phosphorus budgets under existing condi-
tions, response models can be used to evaluate existing lake conditions and to
predict changes in phosphorus, chlorophyll a, and transparency likely to result
from changes in phosphorus loading. Several empirical models have been
developed for this purpose. These models are based on statistical analysis of
monitoring data from collections of lakes and reservoirs.
Models vary with respect to applicability, limitations, and data requirements.
The consultant's choice of appropriate models for a given lake or reservoir
should be based on regional experience and professional judgment. The con-
sultant should also consider how closely the impoundment characteristics
(morphometry, hydrology, natural lake versus manmade reservoir) reflect the
characteristics of the lakes that were used to develop a model. It may be inap-
propriate, for example, to apply a model developed in a study of Canadian
natural lakes to an Alabama reservoir with a very different set of conditions.
Eutrophication models are driven by three fundamental variables that are,
calculated from impoundment morphometry, water budgets, and phosphorus
budgets:
(1) Pi = AVERAGE INFLOW PHOSPHORUS CONCENTRATION (PPB)
Total Phosphorus Loading (Ibs/yr)
Mean Outflow (acre-ft/yr)
This is the flow-weighted-average concentration of all sources contribut-
ing phosphorus to the impoundment. If there were no interactions with
bottom sediments, the average inflow, lake, and outflow phosphorus
concentrations would be approximately equal. This basic measure of in-
flow quality is the most important determinant of eutrophication
response and the most frequent focus of long-term management efforts.
It is sensitive to watershed point and nonpoint sources.
80
-------
(2) T = MEAN HYDRAULIC RESIDENCE TIME (YEARS)
Lake Volume (acre-ft)
• Mean Outflow (acre-ft/yr) , .
This variable approximates the average length of time water spends in a
lake or impoundment before being discharged through the outlet.
Theoretically, it 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 greater influences on
water quality. For a given inflow concentration, phosphorus sedimenta-
tion usually increases and lake phosphorus concentration decreases
with increasing residence time. At very short residence times (less than
one to two weeks), algae may have inadequate time to respond, to the
inflowing nutrient supply.
(3) 2 = MEAN DEPTH (FEET)
Lake Volume (acre-ft)
Surface Area (acres) .
Other factors being equal, lakes and impoundments with shallower
mean _ depths aro generally more susceptible to eutrophication
problems. Shallower lakes have higher depth-averaged light intensities
to support photosynthesis and greater sediment/water contact, which
can encourage nutrient recycling. Since both mean depth and hydraulic
residence time increase with lake volume, they are typically correlated.
Models differ with respect to how these variables are combined in equa-
tions to predict lake or reservoir responses for nutrient loading.
One set of equations based on data from northern natural lakes is
presented in Table 4-2 to illustrate modeling concepts. These are only ex-
amples and not necessarily the "best" models to use in a given application; the
lake consultant should determine the appropriate equation.
Two of the equations are based on the Trophic State Index (TSI) developed
by Carlson (1977). This system, used by many States for classification pur-
poses, is essentially a rescaling of phosphorus, chlorophyll a, and transparen-
cy measurements in units that are consistent with northern lake behavior
(Fig.4-5). The Index provides a common frame of reference for comparing
these measurements; its scale is calibrated so that a decrease of index units
corresponds to a doubling of transparency.
Carlson's Index can be used to predict values of one variable from mea-
surements of another. For example, a lake with a measured mean transparen-
cy of 6.6 feet (2 meters) would have a TSI of 50. Based on the scales in Figure
4-5, a mean chlorophyll a of 7 ppb and a mean total phosphorus concentration
of 23 ppb could be predicted for this lake. These predictions are approximate,
however (good roughly to within a factor of 2, assuming that the lake under
study is typical of other northern lakes). ,
Various factors influence relationships among phosphorus, chlorophyll a,
and transparency (Fig.4-1). Carlson's equations reflect relatively high
chlorophyll a and transparency responses found in northern hatural lakes. Tur-
bid, rapidly flushed reservoirs tend to have lower responses and less sen-
sitivity to phosphorus loading.
Residence time:
Commonly catted 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.
81
-------
Table 4-2.—Typical phosphorus loading model equations for Northern lakes.
PI
INFLOW
(D
-> PHOSPHORUS•
Chi. a
> CHLOROPHYLL a >
(2) (3)
SECCHI TRANSPARENCY
(1) A model for predicting lake phosphorus concentration was developed by Larsen and
Mercier (1976) and Vollenweider (1976): \
P(ppb)=_PL__
1 + T-5
This equation predicts that average lake phosphorus concentration, P, will increase
in proportion to the inflow concentration and will decrease with increasing hydraulic
residence time. At low residence times, phosphorus sedimentation is negligible, and
the response is controlled primarily by inflow concentration.
(2) The simplest of the chlorophyll a response models was developed by Carlson (1977):
• Chi. a(ppb) = .068 P146
This equation is similar to others developed from northern lake data by Dillon and
Rigler (1974) and by Jones and Bachman (1978).
(3) A similar relationship was also developed by Carlson (1977) to predict Secchi disk
transparency: ,
Secchi (meters) ='7.7 Chi a"68
This equation is appropriate for lakes and reservoirs in which transparency is con-
trolled primarily by algae! It will overestimate transparency in impoundments with rela-
tively high concentrations of inorganic suspended solids, silt, or color.
PHYSICAL
. APPEARANCE
>10% RISK
"DEFINITE ALGAE"
"HIGH ALGAE"
"SEVERE SCUMS"
RECREATION
POTENTIAL
>10% RISK
"MINOR AESTHETIC PHOB"-
"SWIMMING IMPAIRED"
"NO SWIMMING'
OLIGOTROPHIC MESOTROPHIC EUTHOPHIC HYPEHEUTROPHIC
20 25 30 35 40 45 50 55 60 65 70 75 80
TROPHIC STATE { £ •
INDEX i I -
15 10 S 7 6 5 4 3 2 1.5 1
TRANSPARENCY
(METERS)
CHLOROPHYLL-A
(PPB)
TOTAL
PHOSPHORUS (PPB)
0.5 0.3
0.5 1 2 3 4 5 7 10 15 20 30 40 60 80100 150
S 7 10 15 20 25 30 40 50 60 80 100 150
Figure 4-5.—Carlson's Trophic State Index related to perceived nuisance conditions (Hels-
kary and Walker, 1987). Length of arrows Indicate range over which a greater than 1,0 per-
cent probability exists that users will perceive a problem.
*
82
-------
Heiskary and Walker (1987) describe a methodology for relating lake
trophic state, as measured by phosphorus, chlorophyll a, or transparency, to
user-perceived impairment in aesthetic qualities and recreation potential. The
arrows in Figure 4-5 indicate measurement ranges in which the risk of per-
ceived nuisance conditions (for example, "Swimming Impaired" or "High
Algae") exceeds 1 0 percent, based on surveys of Minnesota lakes. These
ratings may vary regionally.
Figure 4-6 provides additional perspectives on the relationship between im-
poundment phosphorus concentrations and eutrophication responses, as
measured by mean chlorophyll a and transparency. The figure is based on
cross-tabulations of median total phosphorust mean chlorophyll a, and mean
transparency values from 894 U.S. lakes and 'reservoirs (U.S. Environ. Prot.
Agency, 1978). Phosphorus values are classified into six intervals (0-10, 10-
25, 25-40, 40-60, 60-120, 120 ppb), and the probabilities of encountering
mean chlorophyll a and transparency levels in oligotrophic, mesotrophic,
eutrophic, and hypereutrophic ranges have been calculated for each phos-
EPA National Eutrophication Survey
894 U.S. Lakes and Reservoirs
Probability
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Chlorophyll-A
I
10 25 40 60 120>120
Transparency
10 25 40 60 120 >120
Total phosphorus interval maximum (PPB)
Trophic State
Oligotrophic
Mesotrophic
Eutrophic
Hypereutrophic
CHL-A
(PPB)
<4
4-10
10-25
>25
Transparency
(Meters)
>4
2-4
1-2
Figure 4-6.—Responses of mean chlorophyll a and transparency to phosphorus.
83
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Flushing rate: The rate
at which water enters
and leaves a lake relative
to lake volume, usually
expressed as time
needed to replace the
lak@ volume with
Inflowing water.
phorus interval. For,example, if phosphorus is in the 25-40 ppb range, the
probability of encountering a mean chlorophyll a in the eutrophic range (10
ppb) is about .4, or 40 percent, and the probability of encountering a mean
transparency less than 6.6 feet (2 meters) is about .75, or 75 percent. Varia-
tions in the response factors such as depth, flushing rate, or turbidity (see Fig.
4-1) contribute to the distribution of chlorophyll a and transparency that can be
expected for a given phosphorus load. . <
Tracking Restoration Efforts
Figure 4-7 illustrates a type of phosphorus loading diagram often used to
depict modeling results (Vollenweider, 1976). This diagram is developed by
solving the equation for phosphorus concentrations from the Secchi depth of
inflowing waters and the hydraulic residence time (Equation 1 in Table 4-2.)
The dotted lines (representing phosphorus concentrations of 10, 25, and 60
ppb) are not sharp boundaries of lake condition but roughty delineate trophic
state categories based on average phosphorus concentrations. Corresponding
chlorophyll a and transparency probabilities can be derived from Figure 4-5.
The object of the game is to move the lake away from the HYPEREUTROPHIC
(northeast) corner and toward the OLIGOTROPHIC (southeast) corner in Fig-
ure 4-7, usually by reducing watershed point or nonpoint sources and decreas-
ing the average inflow phosphorus concentration (y-axis).
The paths of eight documented restoration efforts are also plotted in Figure
• 4-7, based upon data summarized in Table 4-3. These case studies provide a
context for illustrating important modeling concepts. Figure 4-8 plots measured'
mean phosphorus, chlorophyll a, and transparency for each lake and time
period. These are compared with predicted values derived from the models in
Table 4-2. The predictions are driven by the inflow concentrations and
' hydraulic residence times listed in Table 4-3. These comparisons illustrate
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Rgure 4-7.—Restoration efforts tracked on Vollenwelder's (1976) phosphorus loading
diagram.
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Case Studies
Each of the following sections discusses a particular case study.
Lake Washington, Washington: "You
Should Be So Lucky!"
Between 1957 and 1963, eutrophicatiori progressed with increasing sewage
loadings from metropolitan Seattle.,Between 1963 and 1968, sewage dischar-
ges were diverted out of the lake basin, reducing the total phosphorus loading
to the lake by 69 percent, relative to 1963. Observed and predicted conditions
in 1978 reflect dramatic improvements in water quality that followed within a
year or two after the sewage diversion. Observed phosphorus concentrations
agree well with model predictions for each time period. Decreases in
chlorophyll and increases in transparency were somewhat more dramatic than
predicted by the models. Lake Washington is perhaps the most successful and
fully documented lake restoration project to date.
Onondaga Lake, New York: "Far Out.
Ninety-three Percent Is Not Enough."
Onondaga received primary treated sewage from Syracuse for many years.
Between 1970 and 1985, phosphorus loadings were reduced by over 93 per-
cent as a result of a phosphorus detergent ban, combined sewer repairs, and
tertiary treatment for phosphorus removal. Lake phosphorus levels responded
in proportion to loading reductions and in agreement with model predictions
(Fig. 4-8). No significant improvements in chlorophyll a or transparency were
achieved, however.
The lack of algal response reflects, the fact 'that pre- and postrestoration
phosphorus levels were extremely high (exceeding 100 ppb; note the scale
factor of 5 for this lake in Figs. 4-8 and 4-9). Phosphorus usually does not limit
algal growth in this concentration range, particularly in deeper. lakes. The
chlorophyll model (Equation 2 in Table 4-2) does not apply and substantially
overpredicts algal concentrations. Despite the substantial loading reductions
as of 1985, Onondaga remained well within the hypereutrophic region of Fig-
ure 4-7 and on the flat portion of the chlorophyll response curve shown in Fig-
ure 4-1.
Onondaga illustrates the fact that some lakes subject to point source phos-
phorus discharges may be.susceptible to nuisance algal growths, even with
tertiary treatment to remove phosphorus. Although chlorophyll and transparen-
cy did not respond, the disappearance of severe blue-green algal blooms fol-
lowing the loading reductions was a significant water quality improvement.
Why didn't Onondaga Lake respond like Lake Washington? It started off in
much worse shape (Fig. 4-7). Onondaga has much shorter hydraulic residence
time (.28 versus 2.8 years) and, therefore, less opportunity for phosphorus
.sedimentation. The loading plot (Fig. 4-7) essentially captures the relative
responses of these two lakes to restoration efforts.
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Long Lake, Washington: "What's This?
Reservoir Restoration?"
Beginning in 1978, tertiary treatment of sewage from Spokane reduced the
average seasonal phosphorus loading to this 22-mile-long reservoir on the
Spokane River by 74 percent. This impoundment has a relatively short
hydraulic residence time (.19 year or 70 days). Accordingly, the inflow and
reservoir phosphorus concentrations are similar, and the sedimentation term is
relatively small (Fig. 4-9). Reservoir phosphorus levels responded roughly in
proportion to the loading. Mean chlorophyll a concentrations were reduced by
45 percent and were apparently less sensitive to the phosphorus loading
reductions than predicted by Equation 2 In Table 4-2. Northern lake models
(such as Equation 2) tend to overestimate chlorophyll a sensitivity to phos-
phorus in some reservoirs because of effects of algal growth limitation by flush-
ing and light (Walker, 1982,1985).
Shagawa Lake, Minnesota: "The Little
Lake That Couldn't."
During 1973, external phosphorus loadings to this northern Minnesota lake
were reduced by 75 percent via point source treatment. Although average lake
phosphorus levels during ice-free seasons were reduced by 35 percent, mean
chlorophyll a and transparency did not respond according to model predictions
(Fig. 4-8). The lack of response has been attributed to phosphorus releases
from bottom sediments. These releases reflect historical loadings and the high
susceptibility of this relatively shallow lake to hypolimnetic oxygen depletion
and wind mixing.The fact that lake phosphorus exceeded the inflow concentra-
tion during the postrestoration periocl (Fig. 4-9) is indicative of sediment phos-
phorus release.
Despite the fact that the phosphorus loading diagram (Fig. 4-7) places
Shagawa Lake at the oligo-mesotrophic boundary following load reductions,
mean chlorophyll a concentrations remained in the hypereutrophic range
during the first few years following loading reductions. Over time, the rate of
phosphorus release from bottom sediments may eventually decrease and per-
mit the lake to.respond to the change jn loading. This case points out the fact
that loading models of the type demonstrated here do not account for unusual-
ly high sediment phosphorus release rates, which may defer lake responses to
changes in external loading.
Kezar Lake, New Hampshire: "The Little
Lake That Could (With a Little Help)," Or
"Shagawa Revisited..."
This shallow, rapidly flushed lake was subject to,a municipal sewage discharge
and in hypereutrophic condition for many years. Following installation of phos-
phorus removal facilities in 1970 and, eventually, complete elimination of the
discharge in early 1981, the external loading was reduced by about 75 percent.
Like Shagawa, the lake phosphorus concentration exceeded average inflow
concentration during the initial period following loading reduction (Fig. 4-9).
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Kezar Lake (maximum depth = 27 feet) was thermally stratified in 1981: Sig-
nificant accumulations of phosphorus released from thick, phosphorus-rich
bottom sediments accompanied depletion of oxygen from the hypolimnion.
Surface algal blooms (chlorophyll a = 60 ppb) were experienced during August
1981 and were apparently triggered by escape of hypolimnetic phosphorus
into the mixed layer. , ' ,
Because of sediment phosphorus releases, responses of lake phosphorus,
chlorophyll a, and transparency to the 1981 sewage diversion were less
dramatic than predicted by the models (Fig. 4-8). In 1984, a hypolimnetic alum
treatment was conducted to address the sediment nutrient release problem.
Monitoring data from 1985 indicate that phosphorus, chlorophyll a, and
transparency levels responded in agreement with model predictions following
the alum treatment. This case illustrates use of both watershed (point source
control) and in-lake restoration (alum treatment) techniques to deal with a lake
problem. Decreases in transparency following 1985 indicate that the book is
not'yet closed on Kezar Lake, however.
Lake Moray, Vermont: "Strange Mud.
Si
M'orey is a resort lake sheltered in the mountains of eastern. Vermont. Aside
from the shoreline, the watershed is largely undeveloped. From the late 1970s
to 1985, severe algal blooms and user complaints were experienced at in-
creasing frequency. Summer mean chlorophyll a concentrations ranged from 8
to 30 ppb, transparencies ranged from 2 to 5 meters, and spring phosphorus
concentrations ranged from 17 to 48 ppb. These variations in water quality
could not be explained by changes in land use, other watershed factors, or
climate. Peak algal concentrations were usually found in the metalimnion and
were supplied by phosphorus released from bottom sediments during periods
of summer and winter anoxia. The hypolimnion was relatively thin (mean depth
= 7 feet) and covered approximately 59 percent of the lake surface area. Bot-
tom waters lost their dissolved oxygen early in June and remained anaerobic
through fall overturn. . .
A two-year intensive study indicated that large quantities of phosphorus
were stored in the lake water column and sediments. At peak stratification in
August 1981, for example, the total mass of phosphorus in the water column
was about five times the annual phosphorus loading from the watershed.
Phosphorus balance calculations (see Table 4-1) indicated that the lake inflow
and outflow concentrations were approximately equal, despite the relatively
long hydraulic residence time of nearly two years. Equation 1 (Table 4-2)
predicts that a lake with this residence time should trap 58 percent of the in-
fluent phosphorus. Study results indicated that Lake Morey was particularly
susceptible to phosphorus recycling from bottom sediments because of its
shape (broad, thin hypolimnion susceptible to rapid oxygen depletion) and
iron-poor sediments (Stauffer, 1981).
Model predictions for the Lake Morey pre-restoration period were substan-
tially below observed values of phosphorus and chlorophyll a (Fig. 4-8). This
reflects the fact that, phosphorus retention capacity was unusually low. Ob-
served transparency was higher than predicted, however, because of the ten-
dency for algae to concentrate in the metalimnion, below the mixed layer
where transparencies were measured. .
Because the phosphorus budget indicated that Morey's problems were
primarily related to internal recycling and not to watershed loadings, a hypolim-
netic alum treatment was conducted during early summer of 1986. The treat-
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ment reduced average phosphorus and chlorophyll a concentrations during the
period following treatment down to levels that Were consistent with model
predictions. Despite no significant changes in external loadings, the alum treat-
ment apparently restored Lake Morey to a mesotrophic status, consistent with
its position on the phosphorus loading diagram (Fig. 4-7).
The longevity of the treatment remains to be evaluated through future
monitoring. This is an example of how phosphorus budgets can be used to
diagnose lake problems, regardless of whether or not the solutions involve
reductions in external loading. Sewering of shoreline areas (a restoration ac-
tivity previously proposed and on the drawing boards for Lake Morey) would
have had little impact. .
Wahnbach Reservoir, Germany: "When
All Else Fails.. ."
Wahnbach Reservoir, a water supply for Bonn, Germany, was subject to high
phosphorus loadings from agricultural runoff and municipal point sources
during the period prior to 1977. The resulting severe blooms of blue-green
algae that developed in. the reservoir caused major problems for the water
supply. For various reasons, the loadings from the watershed were largely un-
controllable. In response to this problem, a detention basin and treatment plant
were constructed at the major inflow to the reservoir in 1977. The treatment
plant was designed to remove more than 95 percent of the phosphorus inflow
via sedimentation, precipitation, flocculation with iron chloride, and direct filtra-
tion. Operation of this plant reduced the average inflow phosphorus concentra-
tion to the entire reservoir by about 71 percent. .
As illustrated in Figures 4-7 and 4-8, the inflow treatment restored
Wahnbach Reservoir from eutrophic to oligotrophic status during 1978-1979.
Observed and predicted lake phosphorus concentration dropped below 10
ppb. Chlorophyll a concentrations are consistently overestimated by the model,
although the relative reduction in chlorophyll a is correctly predicted. This rela-
tively extreme and costly restoration measure was justified in relation to the
severe impacts of eutrophication on drinking water quality and water treatment
economics. ,
Lake Lillinonah, Connecticut: "You
Can't Fool Mother Nature ..."
Data from this 10-mile impoundment on the Housatonic River in Connecticut il-
lustrate the sensitivity of some reservoirs to hydrologic fluctuations. During
1977, phosphorus removal was initiated at a municipal point source above the
reservoir. This program reduced phosphorus loading from the point source by
51 percent and reduced total loading to the reservoir by 8 percent during 1977.
Compared to the case studies just discussed, this loading reduction was
relatively small, and a major change in reservoir water quality would not be an-
ticipated. In fact, observed and predicted phosphorus and chlorophyll a con-
centrations were slightly higher during 1977 (Fig. 4-8). The concentrations in-
creased primarily because the flow through the reservoir decreased by about
43 percent during 1977. As indicated by Equation 1 (see Table 4-2), the
average inflow concentration is the most important variable determining phos-
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phorus predictions, particularly in reservoirs with low hydraulic residence
times. Inflow concentration is determined from the.ratio of loading to outflow.
The inflow concentration increased by 14 percent in 1977 because.the small
decrease in loading was more than offset by the decrease in flow.
For both time periods, the models overestimate reservoir phosphorus and
chlorophyll a concentrations and underestimate transparency. Apparently,
phosphorus sedimentation in the Liliinonah was somewhat greater than
predicted by Equation 1. This is not unusual for long and narrow reservoirs
with high inflow phosphorus concentrations (Walker, 1982,1985). The loading
plot (Fig. 4-7) correctly predicts a hypereutrophic status for Liliinonah during
both monitoring years.
Monitoring over a longer time period that includes years with flows similar
to those experienced during 1976 would be required to track the response of
the reservoir to the phosphorus loading reduction. Because the loading reduc-
tion is relatively small, impacts may be difficult to detect in the context of year-
to-year variations. More substantial reductions in upstream point or nonpoint
loadings, or both, would be required to re'store the reservoir to a eutrophic or
_mesotrophic level.
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^^1^^
Chapters
MANAGING THE
WATERSHED
Introduction
The quality of lake-water can be greatly influenced by watershed drainage. There-
fore, restoration should start outside the lake, on the land. An'entire body of land
practices is aimed at exactly that: the techniques called best management prac-
tices, which are dealt with specifically in the last half of this chapter. These prac-
tices originated in the field of agriculture, mainly to prevent soil loss.
Another central concept that this chapter reemphasizes is that lake water
quality is critically linked to the quality of incoming water entering the lake both
from specific discharge outlets (point sources) and from general (nonpoint) sour-
ces. • • / •''.'•.'."-.";
The importance of the lake and watershed relationship cannot be. overem-
phasized. While this Manual often uses the term lake system, it must be kept in
mind that the lake is a system within a larger system, the watershed. The em-
phasis in this chapter is on watershed management practices that are appropriate
for lake homeowners, lake associations or districts, and small lake communities.
The Lake-Watershed Relationship
Muddy waters, decreased depth, rapid filling from silt, aquatic weeds, algal
blooms, and poor fishing are typical problems of many lakes. Very often, to find .
the cause it is necessary to look away from the lake to the surrounding land.
As Chapters 2 and 3 pointed out, the watershed contributes both the water re-
quired to maintain a lake and the majority of the pollutant loads that enter the
lake. Effective lake management programs, thus, must include watershed
management practices. Trying to solve lake problems without correcting the
source or cause of the problem is not only shortsighted, it rarely works.
Pollutant loads to the lake can be contributed from the watershed as either
point sources or nonpoint sources. Point sources arise from a definite or distinct
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source such as a'wastewater (sewage) treatment plant, industrial facility or
similar source that discharges through a pipe, conduit, or similar outlet. They cari
be identified by tracing the discharge back to a specific source. Point sources
were traditionally considered to be the primary suppliers of pollution to water-
bodies. This is no longer true for most lakes. Harder to identify and harder to con-
trol, nonpoint sources are more likely to be the principal contributors of nutrient
and sediment loads. -r •• . • .
Point sources are usually controlled through wastewater treatment facilities
and State and federally regulated permits such as the National Pollutant Dis-
charge Elimination System. .
Nonpoint sources, by contrast, do not originate from a pipe or single source
but from silt, nutrients, organic matter, and other pollutant loads that are dis-
tributed over a relatively broad watershed area. When water runs over land sur-
faces, it picks up these materials and transports them to the lake, either directly
with runoff or through a tributary stream or groundwater system. Water running off
a lawn or driveway during a heavy rain is a common sight—this is nonpoint
source runoff. Although nonpoint source loadings can occur anywhere in the
watershed, land uses such as agriculture, construction, and roadways contribute
higher nonpoint pollutant loads than other land uses such as forests.
It is not always easy to distinguish a point source from a nonpoint source. For
example, parking lot runoff is considered a nonpoint source, but the runoff typical-
ly enters the lake or stream through a drain pipe or culvert. For regulatory pur-
poses, stormwater runoff from pipes and culverts that are required to have dis-
charge permits is considered a point source. In this chapter, point sources are
defined as homes, factories and other industrial concerns, wastewater treatment
plants, and similar structures that discharge wastewater through a pipe.
For regulatory purposes, wastes from homes on septic .systems are con-
sidered nonpoint sources^ In this chapter we discuss home wastewaters with
point sources since the discharge is discrete and easily identifiable. Nonpoint
sources will include all other sources of pollutant loadings to the lake or stream,
including lawns, driveways, subdivision roads, construction sites, agricultural
areas, and forests.
Point Sources
Wastewaters from industrial, municipal, and household sources can be highly en-
riched in organic matter, bacteria, and nutrients. Wastewater pollutants can be
extremely harmful to lake water quality, even when toxics or pathogens are not in-
volved. For example, when incoming water is high in organic matter, the bacteria
that decompose organic matter can consume the lake's dissolved oxygen supply
more quickly than it can be replenished. The danger of this is especially strong in
thermally stratified lakes, where hypolimnetic oxygen may be totally depleted.
These oxygen depletions can lead to fishkills, odors, and noxious conditions. _
As organic matter decomposes, it can also contribute additional nutrients to
the water. The purpose of wastewater treatment is to remove the majority of the
oxygen-demanding matter, bacteria, and nutrients.
Most wastewater treatment plants have low discharge rates; over 75 per-
' cent of all publicly owned treatment plants discharge less than 1 million gallons
per day (mgd). Sewage treatment ponds or lagoons—the most common type of
wastewater treatment facilities — typically have discharge rates of less than 1
mgd. These low discharge rates, however, do not mean the nutrient or organic
loads from these systems have an insignificant effect on lakes and streams.
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At just 10 to 50 parts per billion (ppb) total phosphorus concentration in the
water, some lakes develop algal blooms, murkiness, and other problems. The
average, total phosphorus concentration of wastewater treatment plant dis-
charges Is about 100 to 500 times greater. in~the summer, wastewater discharges
may dominate streamflow during dry periods when total flow is lower than usual,
and water cannot hold as much dissolved oxygen as it does during the cooler
periods of the year. „
This'combination of high, oxygen-demanding organic loads and lower than
normal dissolved oxygen levels is stressful enough in itself, but the problem is
compounded when these high-organic, low-oxygen conditions coincide with the
peak growing season for algae and macrophytes. The incoming nutrients act as a
fertilizer, encouraging excessive algal and macrophyte growth, which places addi-
tional stress on the dissolved oxygen supply as these plants decompose.
Natural areas, such as wetlands around a lake, have occasionally been used
for advanced wastewater treatment because they can function as a biological fil-
ter to remove silt, organic matter, and nutrients from an inflowing stream to the
lake and thereby improve lake quality. Wetlands, however, can also contribute or-
ganic matter and nutrients to lakes under some conditions. 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 is a subject
that needs more study. Researchers are looking at the use of constructed wet-
lands for wastewater treatment, which is still in an experimental stage.
The Federal Clean Water Act, which established the National Pollutant Dis-
charge Elimination System to regulate the discharge of nutrients and organic mat-
ter from wastewater treatment facilities, provides financial incentives and
authorizes punitive actions to encourage the improvement of these facilities.
Wastewater treatment facilities are regulated by a State's water pollution control
agency or by EPA. Many stormwater drains also are regulated through permits.
Information on permitted facilities discharging into a lake or streams entering a
lake can be obtained by contacting the State water pollution control agency. If a
problem appears to exist with a local treatment plant discharge, this agency or the
State health department should be notified. ,
Wastewater Treatment
Choosing the Scale of the System
If point sources are the most important contributor of organic matter, bacteria, and
nutrients, good wastewater treatment will.be critical to protecting the lake. The
better the wastewater system, the fewer the algal blooms, aquatic weeds, and
odors in the lake. Regardless of the treatment system, however, all treatment sys-
tems require proper design, operation, and maintenance. These requirements
vary among treatment systems, but no system can be installed and then ignored.
Systems must be maintained and properly operated.
Municipal Systems
Typical waste treatment systems for larger cities and municipalities include a con-
ventional sewer system leading to a treatment facility such as an activated sludge
treatment system. Primary wastewater treatment uses screens and sedimenta-
tion (settling) to remove the larger floating and settleable organic solids. Organic
matter dissolved in the wastewater can still exert considerable oxygen demand,
however, so secondary treatment is used to reduce oxygen demand before the
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wastewater is discharged into the lake or stream. Secondary treatment uses
biological and chemical processes to remove 80 to 95 percent of the organic mat-
ter in the wastewater. Primary, and secondary treatment, however, do not sig-
nificantly reduce dissolved nutrient (nitrogen and phosphorus) concentrations.
Total phosphorus concentrations in untreated domestic wastewater are
reduced about 4 percent by primary treatment and about 12 percent using secon-
dary treatment. Total nitrogen has a higher removal rate, about 40 percent of the
total nitrogen removal with primary treatment and about 58 percent removal with
secondary treatment. This means, however, that about half the total nitrogen and
almost all the total phosphorus stays in the wastewater after secondary treat-
ment.
Another level of treatment tertiary or advanced treatment is required to sig-
nificantly reduce nutrient concentrations in the wastewater. Several tertiary treat-
ment procedures are available and more are being studied, but since this level of
treatment is relatively expensive, it has not been applied to the same extent as
secondary treatment.
The best procedure for handling wastewater discharges is to divert them away
from the lake, out of the watershed. Lake Washington (see Examples of Point
and Nonpoint Improvement Projects) is a classic example of how lake quality
can improve after point source diversion. Another approach that has been used
when diversion is not possible is dilution or flushing, which requires a relatively
large source or supply of high quality (low in nutrients and organic matter) water
to dilute the wastewater discharge and increase the flushing through the lake
(Welch and Tomasek, 1980). These procedures have been used primarily with
municipal wastewater treatment plants.
Normally, conventionaf treatment systems are not the best alternative for small
communities and individual homeowners. Conventional treatment plants include
systems such as activated sludge, biofilters, contact stabilization, sequencing
batch reactors and land treatment, and large-scale lagoons. More detailed infor-
mation and fact sheets can be found in the EPA Innovative and Alternative Tech-
nology Assessment Manual (EPA No. 430/9-78-009, published in February 1980).
Conventional treatment plants generally are complicated mechanical sys-
tems. They typically use large amounts of energy and are expensive for small
communities to build. In addition, they require skilled operators to run and main-
tain them. Wastewater is collected in most conventional systems by gravity, but
the cost per household of gravity sewers is high in small communities and in-
creases greatly in rural areas or wherever the ground is hilly, rocky, or wet.
Small-scale Systems
Several small-scale treatment plants' and designs are available for a small city,
town, or village. Even smaller-scale treatment systems exist that are suitable for
thelake homeowner or lake association. The choices can range from individual
on-site systems to larger treatment and collection systems servicing several
homes or small communities (Table 5-1). Characteristics of these treatment sys-
tems, including their status, application, reliability, limitations, cleaning, and treat-
ment side effects are described in more detail in Appendix C.
On-Site Septic Systems
Individual home sewage disposal systems are referred to as on-site septic sys-
tems. The most common on-site system is the septic tank and drain field (Fig. 5-
1). The septic tank provides primary treatment by trapping solids, oil, and grease
that could clog the drain field. The tank stores sludge (solids that settle to the bot-
tom) and scum, grease, and floating solids until they can be removed during
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Table 5-1.—Examples of small-scale treatment plants and designs
EXAMPLE
REMARKS
1. SepticTank
2. Septic Tank Mound System
3. Septic Tank - Sand Filter
4. Facultative Lagoon
5. Oxidation Ditch
6. TrickNng Filter
7. Overland Flow Treatment
A septic tank followed by a soil absorption bed is
the traditional onsite 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
problem soil conditions preclude the use of subsur- '
face 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 contain an intermediate layer of sand as
filtering material and underdrains 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 anerobic bottom layer, an
aerobic surface layer, and ah 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, comminution, or grit
removal 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 biolog-
ical treatment. Slimes form on the rocks and treat
the wastewater. The bed is dosed by a distributor
system, and 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 also by plant uptake. An
underdrainage system serves to recover the
effluent, to control groundwater, or to minimize
trespass of wastewater onto adjoining property by
horizontal subsurface flow. • ' ,
regular septic tank cleaning (every 2 to 4 years, depending on use). Solids and
liquids in the tank are partially decomposed by bacteria. The wastewater that
remains after solids are thus removed 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 associated with the wastewater aid decomposition.
As wastewater flows through the drain field, phosphorus is reduced by .ad-
sorption to soil particles. Nitrogen, however, is primarily reduced by biological
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Inspection
Building paper
Disposal field section
Septic tank cross section
Figure 5-1.—Septic tank and drain field.
processes. Bacterial decomposition in the drain field lowers the oxygen
demand of wastewater before it enters the lake or groundwater.
Some bacteria also convert ammonia nitrogen to nitrate in the drain field.
While this reduces oxygen demand in the water, nitrate tends to move with the
flow, eventually'entering the lake in the groundwater. Since ammonia and
nitrate are fertilizers, they encourage algal growth.
Septic, systems can be effective in removing organic matter, bacteria, and
nutrients if properly designed and maintained. They only work, however, if the
proper site conditions exist. Many lakeside lots are inappropriate for septic sys-
tems, and lake problems have conclusively been associated with septic system
failures. Conditions that prevent or interfere with proper function of septic sys-
tems include unsuitable soils, high water tables, and steep slopes, as well as
system underdesign or improper use. Many of these soil conditions occur
around lakes and can make lakeside lots unsuitable for septic systems.
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 so rapidly.
Saturated soils also hinder treatment because they cannot adsorb nutrients
well. To work properly, septic systems need good contact between the waste-
water and relatively dry soil particles, which adsorb nutrients as the wastewater
passes through the system. Soils that drain very slowly may be chronically
saturated and the system will, therefore, be 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 especially green grass growing over the drain field indi-
cates that wastewater'nutrients are fertilizing the lawn on the way up. High
groundwater tables can also prevent treatment by periodically flooding the
drain system. Steep slopes cause either rapid flow-through or surfacing of
wastewater.
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Frequently a septic problem can be traced to improper use and subsequent
malfunction. These problems commonly arise from underdesign, that is, too*
small a tank or an inadequate drain field. Other problems are caused by serv-
ing more people than the system was designed for, disposing of products that
contain toxics, following a poor septic tank maintenance schedule, and putting
solids in the system (using a garbage disposal). Many health departments and
environmental agencies have a good reference brochure on the function and
design of septic systems. EPA's design manual gives information about on-stte
wastewater treatment and disposal systems (U.S. Environ. Prot. Agency,
1980b)..
Alternative on-site wastewater treatment techniques, such as mound sysr
terns (Fig. 5-2) and sand filters (Fig. 5-3), may be more suitable for many
lakeside properties. These systems use the septic tank for solids removal but
not the typical soil drain field.
The mound system is suitable for rocky or tightly bound soils or areas with a
high water table. Instead of a drain field, a mound is created with fill material.
The wastewater from a septic tank is pumped up to the mound and allowed to
seep through the soil, which provides the treatment (Fig. 5-2).
Figure 5-2.—Mound systems.
A sand filter system can also be used where soils are unsuitable for con-
ventional drain fields. A 2- to 3-foot bed of sand is installed in the soil or
abovegrouhd to filter wastewater as it is released from the septic tank. The fil-
tered wastewater can be disposed of through the soil as in a conventional sep-
tic drain field (Fig. 5-3). .
Septic tank
Recirculation tank
Chloririator
(optional)
Stream
discharge
Figure 5-3.—Sand filters.
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Mound and sand filter systems represent only -minor modifications to the
typical septic system. They do not require major construction or substantially
increase the cost. However, if the groundwater movement is toward the lake,
effluent from these systems will flow in that direction. For any dn-site system,
very careful attention must be paid to the conditions of the site (including
groundwater flow), to, the suitability of the system-for treating the waste, and to
providing proper maintenance of the system.
Holding tanks with.or without chemical treatment can eliminate the dis-
charge problem. Because they must be pumped on a regular basis to remove
the wastewater, holding tanks are not as convenient as conventional systems,
but for cottages or homes that receive limited weekend use, they can be an ef-
fective alternative to other treatment techniques and will reduce local lake
problems.
As with the septic tank/drain field system, soil characteristics, groundwater
tables, usage conditions, slope, and other factors can influence the selection,
design, and operation of alternative on-site treatment methods. Local health or
water pollution control agencies can assist the property owner in evaluating
these conditions and selecting the appropriate treatment system, either con-
ventional or alternative.
Community Treatment Facilities
For communities where existing sewage treatment facilities are adequate and
available, the solution is simply to tie into the public sewer system. Convention-
al sewers are usually by far the major capital cost item of a wastewater system.
However, alternative sewer system designs are available that are much
cheaper than conventional systems and can also be tied into the public sewer
system. These smaller sewers are installed at shallow depths. They have no
manholes and fewer joints, which reduces rain and groundwater intrusion, thus
reducing the treatment plant capacity required to treat this additional water.
There are three general types of alternative sewer systems that, might work
better for small communities or individual homeowners when a major municipal
or regional facility already exists and has available capacity. The first uses
small-diameter gravity sewers that carry septic tank effluent away from the
home. The pipes, which are usually plastic and can be four inches in diameter,
are placed at-less slope than a conventional sewer. Operation and main-
tenance requirements are low.
The second type—pressure sewer systems—use a small pump at each
house to move wastewater under pressure through small diameter plastic
pipes to a treatment facility or a larger interceptor sewer (Fig. 5-4).
The third general type is a vacuum sewer system (Fig. 5-5) that draws
wastewater from each home through small collector pipes to a central collec-
tion station by vacuum. Wastewater. entry into the system is controlled by
vacuum valves at each home or at groups of homes. The vacuum collection
station houses a pump that then delivers the collected wastewater to either the
treatment facility or an interceptor sewer. Because of their limited ability to lift
wastewater, vacuum sewers are best suited to flat areas where gravity sewers
would be too expensive. '
In many communities, however, small-scale treatment is the only feasible
approach, but site conditions prohibit the use of on-site systems. Where lot
sizes or soil conditions are not suitable for on-site systems, cluster systems
can be used (Fig.'5-6). Here, wastewater is conveyed by small-diameter
100
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2"-12" Plastic
Pressure Main
•Dweilihg
1 "-2" Plastic
Service Piping
Ball or
Gate Valve
X
Septic
Tank
Effluent Pump
Check Valve
* Pumping
Chamber
Figure 5-4.—Pressure sewer systems.
Sewage
Buffer
Volume
Interface
Valve
Vacuum
Pump
3"-6" Plastic
Vacuum Mains
Transport Pockets
To Treatment
Facility
Sewage
Pump
Figure 5-5.—Vacuum sewer system.
sewers to a neighborhood drainfield, mound, or sand filter. Construction and
operating costs for on-site or cluster systems are usually low, and the systems
can be very simple to operate. The key to their success is an efficient organiza-
tion to manage their operation and maintenance.
Some treatment systems are particularly appropriate for small com-
munities. Among the simple and reliable central treatment systems' that .are
well suited to small community situations are ponds and lagoons, trickling fil-
ters (Fig. 5-7), oxidation ditches, and overland flow treatment (Fig. 5-8). These
systems .are described in more detail in Appendix C, including their ad-
vantages, disadvantages, maintenancet and cost. All of these well-established
methods provide standard or better levels of treatment. In general, they cost
less to build and run than the common method of treatment called activated
sludge. .They also use less energy and are easier to operate and maintain.
When a community is starting to plan a wastewater project, it should select an
engineer who has experience with these'small community technologies. If the
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CLUSTER SEPTIC SYSTEM
Figure 5-6.—Cluster sewer system.
ongoing project did not consider these technologies, a reevaluation of alterna-
tives might be in order. Information on particular systems apprppriate for small
•communities can be obtained from local contractors specializing in wastewater
treatment, the local or State health departments, water pollution control agen-
cies, or EPA. EPA has several excellent publications available, including the •
Innovative and Alternative Technology Assessment-Manual (EPA No. 430/9-
78-009). ' , •
Figure 5-7.—Trickling filter.
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SPRAY APPLICATION
EVAPOTRANSPIRATION
GRASS AND VEGETATIVE LITTER
ROUNDOFF COLLECTION
Figure 5-8.—Overland ftow system.
Water Conservation to Reduce
Lake Problems
With a lake nearby, conserving water might not seem critical. Reducing water
usage, however, also reduces wastewater discharges. Water-saying devices
such as flow-reducing showerheads and water-saving toilets can cut
household wastewater flows by as much as 25 percent (U.S. Environ. Prot.
Agency, 1981). Tabje 5-2 lists several water conservation procedures taken
from a bulletin issued by the local Arkansas Cooperative Extension Service
(U.S. Dep. Agric. 1984); County Extension offices have more information on
this topic and others that may be of interest to lake managers and
homeowners. Most of these procedures are very simple, even obvious, but the
water they conserve can per/nit smaller wastewater treatment facilities if these
procedures are followed in homes around the lake! Even if a smaller treatment
facility is not possible, reducing water use can lower day-to-day operating
costs for expenses such as treatment chemicals and utilities.
Water conservation is particularly appropriate in cases where existing treat-
ment capacity is limited or near the maximum. If a community is connected to a
regional sewer system, conservation measures can 'effectively reduce treat-
ment charges, which are usually based on the volume of sewage treated. This
volume, in most cases, is monitored through water meter readings, and the
treatment charge is prorated on a household water usage basis.
Water conservation, then, not only costs less in the long run but also
reduces the potential loading of organic matter and nutrients to the lake, partly
as a result of reduced wastewater discharges. More careful usage may also
lower nonpoint source loadings from activities such as watering lawns.
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Table 5-2.—Conscientious use of water can prevent excess run off and reduce
the volume of waste water 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 backwashes. 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 tank 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 tissues, etc. Each flush uses 5 to 7
gallons of water. Items carelessly thrown in
could clog the sewage disposal problems.
• 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
C9ld waterfor meals. Shake bottle before
serving to incorporate air in the water so
that 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 dish-
washer uses about 9 to 13 gallons to
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 com-
plete 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 fortomaloes 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 area
where hottest water is needed—usually
in the kitchen/laundry area.
How to Assess Potential
Sources
Consider the relative importance and contributions of point sources and non-
point sources to the lake. Preparing a water and nutrient budget as discussed
in Chapter 3 and described in Chapter 4 is an essential beginning.
The watershed to lake surface area ratio is.also important. This ratio can in-
dicate whether point or nonpoint sources are likely to dominate water quality.
This ratio is quite simple to calculate: Lake area ratio equals the watershed
104
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area divided by lake area (computed iiyacres). If the watershed is small, local
point sources and septic tank drainage are probably quite important. As the
watershed to lake surface ratio increases, these sources might still be impor-
tant, but nonpoint sources also must be considered.
Assessing Point and Domestic
Wastewater Sources
With an existing on-site system, the first step is to contact the local or State
health department or water pollution control agency to determine whether the
system is operating satisfactorily. If,it is, finding out how to maintain the system
in good condition is all that is necessary. If the system is not working well, how-
ever, correcting the malfunction will be necessary. The agency that checked
the system can provide advice and referrals for further information and may
even offer services to correct treatment system problems.
When considering an on-site system, the individual homeowner or com-
munity should contact the local city or county agent and find out what ordi-
nances may exist for minimum setbacks from the lake, mandatory wastewater
treatment, or other requirements.
If it is absolutely necessary for a. community treatment system-to discharge
to the lake, it is important to determine whether the additional phosphorus
loading will promote algarproblems. Chapter 4 describes evaluation methods;
however, it is strongly recommended that wastewaters not be discharged
directly to a lake.
A community treatment system may already be discharging into the lake or
into a stream that enters the lake; however, information on whether it does and
whether it meets permit requirements is available from the local or State water
pollution control agency. When a community system does discharge directly to
the lake or incoming stream, it is importantto check the discharge area during
the summer for problems such as algal blooms, turbid water, or other condi-
tions. The permit for each .treatment facility is periodically available for public
review and comment before being reissued. If it appears that problems are oc-
curring in the lake, the local water pollution control agency should be notified.
Remember, for any point source treatment system to be effective, it must
be maintained and properly operated. This is true for all treatment systems
from the septic tank on your lot to the community treatment system, if you have
a sewer. You cannot install a system and then walk away and expect it to
protect your lake. Point source treatment works when the systems are main-
tained and properly operated.
Nonpoint Sources
The importance of nonpoint sources of pollution became apparent as
municipal and industrial point sources were controlled. In many cases,
projected reductions in nutrients and improvements in water quality were not
reached. Agencies responsible for lakes and streams attempted to find out
why. Point sources, which had been perceived to contribute to the majority of
water quality problems, had masked nonpoint source pollution problems. Once
point sources were subjected to corrective actions, the importance of nonpoint
105
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sources became apparent. 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 being
affected-by diverse sources of pollutants.
By approaching the management of lakes and streams from a broader
perspective, water managers and scientists found'that in many systems non-
point sources were equal to or greater than point source contributions. The
EPA Administrator reported to Congress that, as of 1988, 45 percent of the
Nation's lakes were either impaired, partially impaired, or threatened by pollu-
tion (U S. Environ. Prqt. Agency, 1989); 76 percent of the lake impairment is re-
lated to nonpoint source pollution, and only 11 percent is related to point
source pollution. The remaining sources of pollution are natural. In general,
nonpoint sources were major contributors of sediment organic matter and
nutrients to a lake. Although the nutrient concentrations in runoff waters or the
amount of nutrients adsorbed to the sediments were not as great as the
nutrient concentrations in a point source, the total load (concentration times
flow) can be substantial and,far exceed point source contributions.
Cultural Sources of Sediments,
Organic Matter, and Nutrients
Figure 5-9 illustrates a typical scene from the window of a lakeside home.
Many of the following sources of nutrients and sediments to the lake are
depicted:
.-• Flower and vegetable gardens—contribute nutrients, sediments,
and pesticides if not properly managed
• Septic tank systems—contribute nutrients and bacteria .
• A well-manicured lawn—contributes nutrients (fertilizers) and
herbicides
Although not illustrated, car maintenance can contribute nutrients to a lake
from washwater and oil slicks from improperly dumped motor oil. The very
presence of people on a lake conducting day-to-day activities is, in part,
responsible for nutrients and sediments that accumulate in the lake.
These examples of pollutants come from an individual lot. Even if the in-
dividual contribution is insignificant, the cumulative contribution from all the in-
dividual lots surrounding a lake could be significant. It is very important that
homeowners living near the lake exhibit concern for their own pollution if they
wish to convince other homeowners in the watershed to improve their habits.
As explained earlier, nonpoint sources are likely to be important in large
watersheds. A common method to determine the relative importance of various
sources of nutrients and sediments to a lake is to determine the area of the
watershed in relation to the area 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 1 to 1 (also represented as 1:1). In small
watersheds (for example, a 1:1 ratio), the local sources of organic matter and
nutrients, such as septic systems and runoff from lawns and gardens carrying
nutrients, might represent the primary contributors of pollutants to the lake.
Additional sources of nonpoint source pollution in a small watershed are il-
lustrated across the lake in Figure 5-9. Construction activities can be sig-
106
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.."• WASTE &
- DETERGENTS'-
Figure 5-9.—Watershed activities as seen from Individual homeslte.
nificant sources of sediments, especially during-rainstorms. Runoff from roads
are additional sources of nutrients, sediments, and heavy metals.
As the watershed to lake surface area ratio becomes larger, other sources
of pollutants such as agricultural runoff carrying animal wastes (organic mat-
ter), soil, and nutrients become increasingly important. Urban runoff from
streets, storms, and rooftops will become significant sources of sediment, or-
ganics (oils and greases), nutrients, and heavy metals to lakes. Silvicultural
activities also will become increasingly important as sources of sediments. In
large watersheds, the contributions from urban, Silvicultural, and agricultural
areas are generally more significant than those from lakeshore homes.
What are Best Management
Practices?
Before a discussion is initiated on how to restore a lake, background on tech-
niques available to improve water quality must be developed.
The lake association or local residents have a number of options available
to improve the water quality of the lake. They range from picking up litter
around the lake to the implementation of best management practices in the
watershed. Best management practices have been developed for agricultural,
Silvicultural, urban, and construction activities! Agricultural practices, for ex-
ample, have been developed for cropland, pastures, barnyard or manure
management, and pesticide control. Silvicultural practices have been
developed for activities such as road construction in timberlands, timber har-
vest techniques, regenerating forest lands cut or killed by disease or fire, and
the use of pesticides. Urban practices have been designed to keep city streets
107
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rf - '
and roadsides clean, while construction practices were developed for. erosion
and runoff control.
In general, these best management practices were not designed with water
quality protection as a goal but rather to maintain productivity on the land,
reduce costs of pesticides and fertilizers, or prevent lawsuits because of mud
slides or flooding on neighboring properties. Regardless of their original intent,
many of these practices are useful in lake restoration prpjects. ,
Managers of lakes and streams focus on best management practices to
control four primary, interactive processes: (1) erosion control, (2) runoff con-
trol, (3) nutrient control, and '(4) pesticide or toxic controls. These processes
are highly interactive because runoff control, for example, offers benefits for
reducing sediments, nutrients, and pesticide contamination in lakes and
streams. Control for other factors, however, may still be necessary. Runoff con-
trol, for example, may minimize water erosion, but wind erosion may account
for 10 to 14 tons of soil loss per acre every year from croplands in some of the
Great Plains States.
Table 5-3 lists various best management practices applied during different
land use activities. Definitions and explanations as to their effectiveness, capi-
tal costs, longevity, confidence, adaptability, potential effects, and concurrent
land management practices can be found in Appendix D. In this analysis, effec-
tiveness refers to how well a practice reduces sediments, organic matter,
. nitrogen, phosphorus, and runoff. Capital costs refers to the costs that would
be incurred by the farmer, forester, contractor, or municipality to implement the-
best management practice. Operational and maintenance costs refers to those
costs required to keep the best management practice working properly.
Table 5-3.—A list of Best Management Practices applied during different
, land use' activities. • '
BEST MANAGEMENT PRACTICES .
AGRICULTURE
CONSTRUCTION
Conservation Tillage
Contour Farming
Contour Stripcropping
Integrated Pest Management
Range and Pasture Management
Crop Rotation
Terraces
Animal Waste Management
Fertilizer Management
Livestock Exclusion
URBAN
Porous Pavements
Flood Storage
Street Cleaning
SILVICULTURE
Ground Cover Maintenance
Road and Skid Trail Management
Riparian Zone Management
Pesticide/Herbicide Management
Nonvegetatiye Soil Stabilization
Disturbed Area Limits
Surface Roughening
_ MULTICATEGORY
Streamside Management Zones
Grassed Waterways
Interception or Diversion Practices
Streambank Stabilization
Detention/Sedimentation Basins
Vegetative Stabilization
108
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Longevity is either short term or long term. For this discussion, short term
means the practice is good only for a year or season. Long-term practices are.
those that last longer than one year. The terminology is not clear-cut because
some practices have to be applied every year buLare considered to be long
term because the implementation of the practice is not designed to provide in-
stant results. An example is conservation tillage. In conservation tillage, plant
residue is left on the field after harvest. When a conservation tillage practice is
initiated, the farmer does not expect to have significant results in the first year
but will be able to maintain or protect the productivity of the land over the long
haul. The benefits the lake receives are also not noticeable in the first year but
will be perceived over a period of years.
Confidence is based upon how consistently a best management practice
works in reducing a problem. One might have little confidence in a best
management practice that works only on a hit-or-miss basis. In many cases,
the scientific evidence is not yet available to assess the confidence associated
with a given best management practice.
When,a best management practice can be used in a variety of geographic
areas and situations, it is considered to be adaptable. For example, the adapt-
ability of conservation tillage is ranked as good instead of excellent because it
is limited in northern States that experience late, cool springs or in heavy, poor-
ly drained soils, even though it can be applied in a variety of geographic areas.
Potential treatment side effects refer to the possibility of causing another
problem by treating the problem of immediate interest. For example, even
though the use of conservation tillage can reduce soil erosion, runoff, and
nutrient losses, the increased use of chemicals may lead to groundwater pollu-
tion. ' ; ,
. When a best management practice is applied, there is generally a support-
ing best management practice that will increase the effectiveness of the
primary practice. In the case of implementing a conservation tillage program, a
fertilizer management and integrated pesticide management program should
also be initiated as a supporting practice.
Table 5.4 summarizes the effectiveness, costs, and chance of negative, side
effects associated with select best management practices. In some instances,
the rankings represent a range such as good (G) to excellent (E). In .other in-
stances, a particular category is ranked as unknown (U). The range of rankings
and the unknowns reflect uncertainties and variable results associated with
best management practices in providing benefits such as sediment nutrient
reduction to a watercourse or lake. The reader should use the table as a •
guideline when selecting best management practices to solve a potential water
quality problem. The local and regional conditions will dictate the particular
combinations of best management practices that are most effective and ap-
propriate for a particular fake. Although there is some uncertainty about the
most appropriate combinations for any watershed, best management practices
work! Like point source treatment systems, however, these practices must be
maintained.
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Table 5-4.—Summary of the effectiveness, cost and chance of negative side effects associated with select
watershed best Management practices. ' ; •
SEDIMENT
EFFECTIVENESS
NITROGEN . PHOSPHORUS
RUNOFF
COST
CHANCE OF
NEGATIVE
EFFECTS
AGRICULTURE
Conservation Tillage
Contour Farming
Contour Stripcropping
Range and Pasture
Management
Crop Rotation
Terraces
Animal Waste Management
URBAN
Pereus Pavement
Street Cleaning
SILVICULTURE
Ground Cover Maintenance
Road and Skid Trail
Management
CONSTRUCTION
Nonvegetative Soil
Stabilization
Surface Roughening
MULTICATEGORY
Streamside Management
Zones
Grassed Waterways
Interception or Diversion
Practices
Streambank Stabilization
Detention/Sedimentation
Basins
G-E
F-G
G
G
G
G-E
N/A
F-G
P
G
G
E
G '
G-E
G-E
F-G
P
U
U
U
F-G
U
G-E
F-G
P
G
U
P
U
G-E
U
F-G
' !
U.
F-E
F
F-G
U
F-G
U
G-E
F-G
P
G
U
P
U.
G-E
P-G
F-G
G-E
F-G
•G-E
G
G
F
NA
G-E
P
G
U
P-G
G
G-E
F-G
P
F-G
G
G
G
F-G
F-G
P
P-G
P
G
P
F-G
F
F-G
P-F
P-G
F-G
P
P
P
P
F
F
F
U
P
F
F
P
P
P
E Excellent
F F»«
U Unknown
G Good
P Poor
Lake Restoration Begins in the
Watershed
The best place for any lake association to start a restoration project is in its
own backyard. There are a number of actions individual lake homeowners can
initiate, for example:
• Collecting the litter tossed in yards and along the roads.
•. Leaving the grass or shrubs uncut up to the lakeshore or along roads
uncut to act as a buffer strip to reduce nutrient and sediment loads to a
lake. ,
• Modifying agricultural best management practices for flower or
vegetable gardens. Although agricultural best management practices
were designed for large fields (40 to 1,000 acres), they can be scaled to
backyard plots.
• Adopting a form of conservation tillage, integrated pest management,
and fertilizer management. Leaving after-harvest vegetable crop residue
in gardens can minimize local sources of nutrients, organic matter, and
sediments.
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Durjng the growing season, integrated pest management and fertilizer
management may be appropriate. Integrated pest management is a practice
that considers the best timing dosage and handling of pesticides for maximum
effectiveness with minimal waste or overuse; Other considerations include
selecting resistant vegetable varieties, optimizing vegetable/flower planting
time, rotating plants, and using biological controls. Local Extension agents are
good reference sources for locally suitable resistant plant varieties.
Fertilizer management considers the proper time to spread a fertilizer and
the proper amount to optimize plant growth with minimal impact on the lake.
Management of fertilizers and pesticides actually saves money because the .
proper amount is applied when it does the most good. This reduces both the
amount and the number of times fertilizers and pesticides need to be used.
Again, the local Extension agent can be of assistance. In addition, U.S. Soil
Conservation Service personnel can provide information on locally dominant
soil types and assist in determining the appropriate amount and type of fer-
tilizer.
Once lake homeowners' have initiated best management practices on their
own lots, it is time to start moving outward into the watershed. By working
together, lakeshore property owners can accomplish a number of small
projects that will help reduce nutrient and sediment loads to a lake. For ex-
ample, eliminating curbs and gutters allows the, road runoff to flow over
grassed areas that will filter sediments and use the nutrients. Other examples
of best management practices that could be applied include vegetative
stabilization, grassed waterways, streamside management zones, streambank
stabilization, and detention/sedimentation basins. These practices, described
in Appendix D, all help reduce the input of organic matter, silt, and nutrients to
the lake.
In a streamside management zone, the natural vegetation is maintained be-
side the stream. If vegetation has been removed, it should be replanted. Plant-
ing erosion-resistant grasses in natural or constructed drainage channels to
make a grassed waterway is another practice that lake associations might en-
courage. In concept, vegetative stabilization is similar to grassed waterways
and streamside management zones, using erosion-resistant plants or ones
that will stabilize soil in erosion-sensitive areas such as steep slopes. If a
stream entering the lake is eroding its banks, however, vegetation may not suf-
fice. Another project that a group might initiate is streambank stabilization
where a layer of carefully graded rocks (riprap) is placed over the area of
erosion. In some cases, a blanket of nonvegetative fiber or layer of sand must
be placed before riprapping. The area may also require detention/sedimenta-
tion basins designed to slow runoff for a short time and to trap heavier sedi-
ment particles. Artificial wetlands have been created in some areas to store
runoff water and decrease flooding but also to trap sediment and nutrients.
Wetlands have been used in Minnesota for stormwater management and lake
protection. Additional information is available from the Soil Conservation Ser-
vice and local drainage improvement districts or land improvement contractors.
With a large watershed, the tasks facing the lake association become more
complex. Now the organization has to work with property owners who may not
live near the lake, private contractors, municipalities (such as zoning commis-
sions), and county planning agencies that may or may not be concerned about
the lake. In some cases, local ordinances or zoning regulations might need to
be passed to regulate construction or other land use activities. The lake or-
ganization may require that construction areas implement best management
practices such as nonvegetative soil stabilization, disturbed area limits,-and
surface roughening. <
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Nonvegetative soil stabilization includes actions such as covering disturbed
areas with mulches, nettings, crushed stone, chemical binders, and blankets or
mats. This best management practice is a temporary measure that should be
used until a long-term cover is developed.
The best management practice known as disturbed area limits is nothing
more than a common sense approach to minimize the area disturbed by the
construction activity. If vegetation is removed, surface roughening can be ap-
plied on the exposed soil. Conventional construction equipment is used to
scarify, or groove, the soil along the contour of a slope. In practice, the grooves
spread the runoff horizontally and increase the time for water to soak into the
ground. ,
As the watershed to lake surface area becomes larger, the task of water-
shed management becomes more expensive and more complex. It is impor-
tant to realize that not all areas of the watershed are equally important and to
identify those that are critical contributing areas so that available funds can be
used effectively. A critical area is one that contributes excessive amounts of
soil and nutrients to the lake, or a stream course that enters the lake. How to
delineate these areas is discussed in Chapter 3, Problem Identification. An
educational program on watershed management should also be considered.
The only reason some individuals contribute nohpoint source loads to lakes is
their lack of awareness of the impact of their actions.
The U.S. Department of Agriculture has a program on low input sustainable
agriculture that is providing farmers information on more cost-effective and en-
vironmentally sound agricultural practices. This program helps farmers in-
crease profits while maintaining and protecting the environment by building on
. multiple best management practices such as integrated pest management and
crop rotations. This program is closely coordinated with EPA's nonpoint source
, programs. Additional information can be obtained from the USDA Cooperative
State Research Service or the local county Extension agent. Educational ap-
proaches are critical in successfully implementing a management plan (see
• Chapter 8). A key to a successful lake management program is maximum local
involvement.
Any one or all of the best management, practices listed in Table 5-3 and in
Appendix D may be applicable in the lake's watershed. The best approach is to
target those areas that are concentrating the most significant sediment, or-
ganics, or nutrient loads. This may entail starting a modest monitoring program
as discussed in Chapter 8. .
The practices just discussed addressed the actions an association can take
around the lake. Maintaining these practices and protecting lake water quality
might require regulations, zoning, or ordinances. These regulatory procedures,
which are discussed in Chapter 9, can be effective tools for lake and water-
shed management.
Guidelines and Considerations
Controlling nonpoint sources and identifying the most feasible alternatives can
be considered a seven-step process.
• Step 1. Form a lake association or lake district. Several voices have
more strength than one. The North American Lake Management Society is an
organization that can help you organize a lake association and put you in touch
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with other like groups. Some States have already formed a federation or con-
gress of lake associations {Appendix E). Members from-other lake associa-
tions can be a good source of information. ,
• Step 2. Identify potential problem sources. Start with the lake home and
then move around the lake and out into the watershed. This is the first step to
define the extent of any problems. Refer to Chapter 3.
• Step 3. Identify Critical Areas. Critical areas are those that are contribut-
ing a majority of the sediments and nutrients to the lake. Not all areas neces-
sarily contribute equally to lake problems. Refer to Chapter 3. Part of
identifying a critical area is common sense. If a farmer is plowing up to the
edge of a stream, a feedlot is located on a stream or lake, or a clearcut is lo-
cated close to a stream, those areas become potential candidates for critical-
areas. In many cases, the lake association will not be able to directly correct
watershed problems created by agricultural, urban, or silvicultural activities.
Ordinances or local zoning regulations might be necessary (see Chapter 9)..
• Step 4. Initiate watershed management practices. Common best
management practices were explained earlier, and it was stated that they were
initially developed for purposes besides water quality improvement. The intent
.of this chapter is to develop in lake associations and lake homeowners an ap-
preciation of the relationship between the lake and the watershed. Generally
no one practice is adequate by itself, and many practices must be integrated.
• Step 5. Determine allocation of resources. A lake association or lake dis-
trict will in all likelihood be limited by resources. The best place to start in any
watershed management program is in the association's own backyard. Many
of the best management practices considered for agricultural, urban, or sil-
vicultural activities can be pursued by lake homeowners on a reduced basis:
buffer strips around the lake are just as applicable to a homeowner as to a
farmer, as are fertilizer management, pesticide management, conservation til-
lage, street cleaning, or nonvegetative soil stabilization. A lake association will
probably be more effective if it corrects local problems before tackling those in
the upper watershed. Common sense is the key.
• Step 6. Investigate regulations and zoning. Consider regulations or
zoning as time and space to resolve lake problems both of land use and lake
users (see Chapter 9). A lake problem is a limitation on a desired use. In some
instances, other lake uses and users are the problems. Some uses will not be
compatible in all lakes, so it is important to decide which lake uses have the
greatest priority and manage to achieve these uses. Regulations can assist in
achieving these uses.
• Step 7. Employ tools in combination. Consider an integrated program of
watershed management an,d in-lake restoration. To develop an effective lake
management plan, all the available tools should be considered and the ap-
propriate ones incorporated in the plan. Chapter 6 discusses the third leg of
the lake management triangle—lake restorations.
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Examples of Point and
Nonpoint Improvement Projects
Lake Washington: Point Source Diversion
Lake Washington is considered a classic example of water quality improve-
ment with the diversion of sewage. In 1958, the public voted to divert sewage
from Lake Washington, but the first diversion did not take place until 1973, and
the system was not completed until 1978. With the first diversion, which
stopped about 28 percent of the effluent, the lake stopped deteriorating, and
during the five-year diversion period, the lake showed signs of recovery. Be-
tween 1967 and 1968, water quality changed rapidly. Edmondson (1972)
reported that the content of phosphorus in the surface waters decreased about
a fourth of its maximum value, microscopic plants decreased, and transparen-
cy increased (see Chapter 4). .
Annabessacook Lake, Cobbossee
Lake, and Pleasant Pond: Point Source
Diversion/Nonpoint Source Waste
Management/ln-Lake Treatments
Annabessacook Lake is an example of a hit or miss approach to lake restora-
tion. For years'it was considered the most polluted lake in Maine. From 1964 to
1971, residents attempted to solve their algae problems with copper sulfate,
but each year the period of effectiveness became shorter and resistant algae
predominated. In 1969, steps were taken to divert sewage from the lake. The'
diversion resulted in an improvement, but algae growth continued to be a
nuisance. To accelerate recovery, hypolimnetic aerators were installed, but
there was no positive response.
After over 30 years of frustration in attempts to improve water quality in the
chain of lakes (Annabessacook Lake,.Cobbossee Lake, and Pleasant Pond),
lakeshore property owners, local officials, and concerned citizens formed the
Cobbossee Watershed District, which was to serve as a quasi-governmental
agency, similar to a school district or sewer authority. Through their taxing
authority, a Federal water quality management (208) planning grant, and the
Agricultural Stabilization and Conservation Service, they were able to conduct
a formal study of nonpoint sources of pollution to formulate a comprehensive
restoration plan.
In Pleasant Pond, agriculture was the dominant source of phosphorus non-
point pollution and the second leading cause in Annabessacook and Cobbos-
see lakes. Lake sediments were the primary source of nonpoint pollution in An-
nabessacook Lake..After careful consideration, a two-pronged approach was
taken. An agricultural waste management program was started in the water-
shed and nutrients were removed from the lake water column. The major
agricultural activities in the watershed were dairy and poultry farming; most
farmers spread the manure on frozen ground and snow. To implement a waste
management program, storage had to be found for six months of accumulated
manure.
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By using animal waste management {storage during winter months) and
alum (aluminum sulfate). plus sodium aluminate to remove phosphorus, the
total phosphorus loads were reduced approximately 45 percent. From the lake
users' viewpoint, the improvement in water clarity has been a positive benefit
(U.S. Environ. Prot. Agency, 1980a).
East and West Twin Lakes: Septic Tank
Diversion
The results of septic tank diversion and alum treatment were part of a research
project (Cooke et al. 1978) funded by the EPA. This study is included because
it demonstrates that septic tanks can affect a lake even when sited in ideal soil.
Prior to septic tank diversion, fecal coliform levels in East and West Twin
Lakes ranged from too numerous to count to 260 colonies per 100 mL The
standard for fecal coliform is 200 colonies per 100 mL, and levels above this
limit resulted in the lakes being closed to contact recreation. After diversion,
fecal coliform levels quickly reformed to near zero levels in groundwater,
streams, and the lakes. Although the septic systems were sited in soils
presumably ideal, Cooke et al. (1978) found perched water tables in the leach
field that, they assumed, were the result of organic material clogging the leach
field and reducing permeability. This situation allowed nutrient-rich and fecal
material to be washed from the lawns to ditches and streams that entered the
lakes.
A concurrent decrease in phosphorus concentrations was not observed be-
cause the lakes continued to receive untreated storm flow and runoff from
diverse nonpoint sources typical of eutrophic lakes. Cooke et al. (1978) con-
cluded that the diversion of septic tanks prevented the situation from becoming
worse and potentially reaching a point where all recreation would have to
cease. .
Summary
Lakes receive nearly all of their silt, organic matter, nutrients, and other pol-
lutant inputs—or loads—from their watersheds. These pollutant loads are con-
tributed both from point sources and nonpoint sources. Point sources, dis-
charged from a pipe, are contributed from such places as homes, offices, and
factories. Point source and domestic wastewater pollutant loads are controlled
with wastewater treatment systems, the most common being the septic tank
and drainfield, an on-site system used by many homeowners.
Septic tanks and drainfields might not be the best on-site system for lake
homes. Alternative systems, such as mound systems and sand filters, and on-
site systems that can treat the wastewater from several homes", lake associa-
tions, or small communities—oxidation lagoons, trickling filters, and overland
flow treatment systems—should be considered.
Nonpoint sources of pollutant loads arise from various watershed land
uses such as agriculture and forestry, construction, and urban activities. These
sources can be controlled by implementing best management practices in the
watershed. '
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Watershed best management practices begin with the individual lake
homeowner. Lake associations-and lake districts can effectively implement
best management practices in the community and promote these practices
throughout the watershed. Watershed point and nonpoint source management
practices implemented in the Lake Washington, Lake Annabessacook, Lake
Cobbossee, Pleasant Pond, and East and West Twin Lakes demonstrate that
best management practices can be used to improve and protect lake quality.
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Chapter 6
LAKE AND RESERVOIR
RESTORATION AND
MANAGEMENT
TECHNIQUES
Introduction
This chapter covers the major restoration and management techniques that are
used within lakes and reservoirs. Somewhat like prescriptions for treating lake ail-
ments, these techniques have benefits, side effects, and limitations. All have
demonstrated and proven value, but none is suitable for every lake, for an all-in-
clusive range of problems, or even for a specific problem under varying cir-
cumstances.
With that warning delivered, what can the reader expect to gain from this
chapter? Its threefold objective is to help the reader
• Understand the limits of lake and reservoir restoration and
management methods,
• Ask the critical questions involved in choosing the,most appropriate
procedure, and
• Become familiar with thei various methods .with regard to their basic
ecological principles, their mode of action, their effectiveness and
potential negative impacts, and—where known—their costs.
The Principles of Restoration
The lake user needs to consider two important ideas regarding lake protection
and restoration before proceeding to study and select methods appropriate to any
particular lake or reservoir: ,
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First, in the long term, the condition of a waterbody is dictated primarily by the
quality and quantity-of water entering it. While there are important qualifications to
this, including biological interactions in the lake, sediment release of nutrients,
and basin shape, it is clear that nearly all attempts at restoration will be over-
whelmed by continued high incomes of silt, organic matter, and nutrients. Protec-
tion and watershed management (see Chapter 5) are therefore paramount to res-
toration. ;
Second, lake restoration is, by definition, the use of ecologically sound prin-
ciples to attempt to return a lake or reservoir to the closest approximation of its
original condition before disturbance. Sometimes it can be made even better than
the original condition. Management, on the other hand, involves the improvement
of the lake or reservoir to enhance some human use or goal such as swimming,
fishing, or water supply. Of course a restored lake is likely to be very attractive for
human activities and will require management to remain in that condition.
Restoration and management techniques can be divided into three general
groups, based upon the ecological principles behind them.
1. Control of plant growth through control of factors such as nutrient loading
or sediment nutrient release
2. Improvement of conditions for populations of desired species, including
certain organisms that might control excessive vegetation
3. Removal of nuisance organisms or sediments.
Lake restoration does not include symptomatic treatments such as an her-
bicide or algicide application, although these chemicals can form an important.
part of a vegetation mahagementprogram. Herbicide treatments, like some other
management procedures, are not restorative because they do not treat the
causes of excessive vegetation and, therefore, must be continually or frequently
reapplied. Furthermore, some of them are associated with undesirable side ef-
fects. .
Costs are a very important consideration, as well. The more management-
and symptom-oriented the technique, the greater the likelihood that the long-term
benefit-to-cost ratio will be poor. While a restoration-oriented technique usually
costs-more at the outset, restoration lasts. For example, it is hardly wise to con-
sider a restoration program that provides at least 10 years' worth of benefits to be.
"expensive" compared to a management."bargain" that has to be repurchased 10,
20, or 30 times in the same time span without ever solving the real problem.
Some readers will be aware of specific products or procedures not mentioned
here. Ultimately, some could be effective and have minimal undesirable side ef-
fects. As these techniques are thoroughly tested and proven to be effective, they
will be added to this chapter. In general, the techniques and products listed in this
Manual have been described in the open scientific literature and are considered
to be effective.
Lake managers should ask for scientific documentation regarding a proce-
dure, product, or technique, especially one not described here. If you are unsure,
discuss a technique with a lake restoration expert not financially involved in its
sale or installation. An agent of the appropriate State agency might be a good
choice. There are too many cases of lake associations spending thousands of
dollars on products and procedures that don't work or are unappropriate to the
problem. An example would be installation of an unneccesary or under-powered
aeration device.
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Are Protection and Restoration
Possible?
Some eutrophic lakes and many reservoirs probably cannot be restored or im-
proved to a condition better than the current condition. Either they cannot be
protected, or the users' expectations are not consistent with achievable condi-
tions'. An estimation of the degree to which a waterbody can be improved is one of
the functions of the diagnostic/feasibility study (Chapter 3), which answers ques-
tions relating to sources of nutrients, silt, and organic matter loadings, and the
present condition of the lake. For example, if the primary source stream is of poor
quality and it is not feasible or practical to improve it/protection will be impossible
and iri-lake or in-reservoir procedures might have only a small effect. For another
example, reducing nutrient loading won't immediately cure an algae problem if
the nutrients already in tne lake's sediments are available to sustain the algae. A
diagnostic/feasibility study will forewarn the lake manager of these possibilities
and suggest the appropriate remedies.
, Reservoirs are extremely difficult to protect and therefore to improve (Cooke
et al. 1986; Cooke and Kennedy, 1989). Reservoirs have features not usually
found with natural lakes that can interfere with any restoration project. Reservoirs
usually have a very large drainage basin, possibly covering several social or
political units. In some areas, reservoirs commonly have a drainage basin with
extensive areas of agricultural nonpoint nutrient, silt, and organic matter dis-
charges, making loadings very high and the probability ofimprovement in stream
quality low. As noted in Chapter 2, reservoirs are usually dominated by a single,
high-volume, source stream. This stream may not only carry a heavy load of silt,
organic matter, and nutrients but may also wash out reservoir restoration treat-
ments, such as phosphorus inactivation, or reintroduce undesirable organisms.
Reservoirs can also have extensive areas of shallow water with dense weed beds
and high sediment nutrient release rates.
* The current uses of the lake or reservoir, or those planned [for it, may be in-
Compatible with the implementation of some restoration techniques or may be in-
consistent with achievable improvements. For example, potable water supplies
must be treated with great care. Not only are most herbicides banned from water
supplies, but some restoration procedures such as sediment removal may require
expensive, special equipment to protect raw potable water quality.
Sometimes limited, specialized uses of a lake or reservoir can make success-
ful management more likely. For example, weed control alone might suffice for a
boating-fishing-waterskiing lake if algal blooms do not interfere with these uses.
The answer, might be found in a management program of harvesting or herbicide
treatment. If the lake is also used for swimming, however, in-lake restoration work
and an expensive stream treatment or watershed management project might be-
come necessary. ,
Some lakes have always been highly productive, and no amount of money or
effort will make these waterbodies. crystal clear and free of algae, weeds, and
shoals. Some geographic areas, or "ecoregions," have richer, more erodible soils,
higher annual precipitation, and more extensive human uses of the land. Loading
to lakes in these regions, even without cultural influences, is high. Therefore, the
goals of lake restoration must be realistically set to limits imposed by natural
background incomes of substances, to the chemistry of sediments, and to certain
human uses of the land.
It is also true that high lake fertility isn't always unwanted; some lakes and
reservoirs are so infertile that fish productivity is low. Management of some of
these lakes can include nutrient additions to stimulate algae growth and an as-
sociated development of game fish populations.
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The shape of the lake's basin is an often overlooked factor. Most natural lakes
are srrtall and shallow and thus offer ideal conditions for plant growth. Those
lakes may be dominated by weed-choked areas; their low volume does little to
dilute nutrient loading; and their sediments offer a rich supply of nutrients to
rooted macrophytes and algae. While some of these lakes can respond well to
restoration efforts, a combination of procedures may be required. In other lakes,
such as those that average less than 7 feet deep, the costs of deepening might
be prohibitive, arid other techniques might provide primarily symptomatic relief at
high cost. ~
The words.restoration and management therefore must be considered in light
of both what is desired by the lake users and what is possible. In many cases, in
addition to the restoration procedure, continual maintenance work will be required
to maintain water quality, and-often the route to long-term improvement will ex-
tend over several years while diagnostic-feasibility studies are under way and
restoration procedures are successively tested and implemented. In all cases,
whether involving lakes in which long-term improvement is predicted or lakes in
which it is impossible, a diagnostic-feasibility study should be undertaken before
deciding on one or more in-lake restoration and management procedures.
Lake and Reservoir Restoration
and Management Techniques
Most of the techniques for managing and improving lakes were developed years
ago, but only in the last decade have enough well-documented data been ac-
cumulated to evaluate these methods. Much of this evaluation research was sup-
ported through the U.S. Environmental Protection Agency's Clean Lakes Program
and by research grants in basic and applied limnology from EPA, the National
Science Foundation, and several other governmental and private agencies and
corporations. The much-needed further development of pur knowledge of lakes
and reservoirs will require continued support by these organizations.
Six types of lake or reservoir problems are frequently encountered by lake
users. These are (l)'nuisance algae; (2) excessive shallowness; (3) excessive
rooted plants ("weeds" or macrophytes) and their attached algae mats; (4) drink-
ing water taste, odor, color, and organics; (5) poor fishing; and (6) acidic condi-
tions. For each of these major problem areas, several in-lake techniques have
been found to be effective, long-lasting, and generally without significant negative
impact when used properly. These procedures will be described under the ap-
propriate problem, with regard to their underlying ecological principles and
mode(s) of action, effectiveness (including brief case histories), potential negative
impacts, and additional benefits and costs. The reader will be referred to further
reports in the basic scientific literature. The less well-studied or less-effective pro-
cedures will also be briefly described.
Basic Assumptions
The following discussions of in-lake technique effectiveness, except where ex-
plicitly stated, always assume that loadings of nutrients, silt, and organic matter to
the lake have already been controlled. Most in-lake procedures will be quickly
overwhelmed by continued accumulation of these substances. To repeat the
theme of Chapter 5: The lake and watershed are coupled. In-lake programs can
complement watershed efforts; however, such problems as algae, turbidity, and
sedimentation may persist despite load reductions or diversion projects unless an
in-lake procedure is also used.
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As for restoration and management techniques that are not mentioned in this
Manual, in nearly every case these procedures have not been described in the
open scientific literature and therefore have not had the benefit of testing, discus-
sion, explanation, and criticism that is so vital to the development of techniques of
proven effectiveness and minimal negative impact. Caution should be exercised
in the use of a procedure not listed here. .
Problem I: Nuisance Algae
Biology of Algae
Excessive algae growth can become a serious nuisance in all aquatic habitats.
Two growth forms are most troublesome in lakes: mats of.filamentous algae as-
sociated with weed beds, and free-floating microscopic cells, called
phytoplankton, that form green scum on the water's surface and contribute to
taste and odor problems. Algae reproduce almost exclusively through cell
division. When growth conditions are ideal (warm, lighted, nutrient-rich), algae
multiply rapidly and reach very high densities ("blooms") in a few days.
The factors that control the abundance of phytoplankton, including blue-green
algae, form the basis for attempts to manage and limit them. Frequently the quan-
tity of algae in a lake can be shown to be directly related to the concentration of
an essential plant nutrient. In many cases this element is phosphorus. Sometimes
the lake and watershed can be manipulated to lower phosphorus concentration
enough to limit algal growth. Some restoration techniques therefore concentrate
on controlling the income of phosphorus or on curtailing phosphorus release and
cycling within the lake. Compared to phosphorus, other essential plant nutrients
(such as carbon and nitrogen) are very difficult to manipulate to control algal
growth. However, other factors important to algal growth can be manipulated to
produce long-term control, such as light. When light and other nutrients are abun-
dant, they can be manipulated to produce long-term controls, such as artificial cir-
culation of algal cells into deep, dark water. In other cases, particularly where
nutrients cannot be manipulated, control might be achieved by encouraging
populations of animals that graze on cells. 'All of these procedures, and others,
will be described in the following paragraphs. -»
Filamentous algae are difficult to control. With the exception of algicide ap-
plications, procedures to accomplish this are often associated with those to con-
trol weeds and, therefore, will be discussed in the-macrophyte section.
Algae—Removal Techniques
with Long-Term Effectiveness
Phosphorus Precipitation and
Inactivation
• PRINCIPLE. The release of phosphorus stored in lake sediments can be so
extensive in some lakes and reservoirs that algal blooms persist even after in-
coming phosphorus has been significantly lowered, as seen in the Shagawa Lake
example in Chapter 4. Phosphorus precipitation removes phosphorus from the
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water-polumn. Phosphorus inactivation, on'the other hand, is a technique to
achieve long-term control of phosphorus release from lake sediments by adding
as much aluminum sulfate to the. lake as possible within the limits dictated by en-
vironmental safety (see Potential Negative Impacts).
These two techniques are most effective after nutrient diversion. Both attempt
to keep phosphorus concentration in the water column low enough to limit algal
growth. " .
• MODE OF ACTION. Iron, calcium/and aluminum have salts that can combine
with (or sorb) inorganic phosphorus or remove phosphorus-containing particulate
matter from the water column as part of a floe. Of these elements, aluminum is
most often chosen because phosphorus binds tightly to its salts over a wide
range of ecological conditions, including low or zero dissolved oxygen. In prac-
tice, aluminum sulfate (alum)' or sodium aluminate is added to the water, and pin-
point, colloidal aggregates of aluminum hydroxide are formed. These aggregates
rapidly grow into a visible, brownish floe, a precipitate that settles to the sedi-
ments in a few hours or days, carrying phosphorus sorbed to its surface and bits
of organic and inorganic particulate matter in the floe. After the floe settles to the
sediment surface, the water will be very clear. If enough alum is added, a layer of
1 to 2 inches of aluminum hydroxide will cover-the sediments iand significantly
retard the release of phosphorus into the water column as an "internal load". In
many lakes, assuming sufficient diversion of external nutrient loading, this will
mean that algal cells will become starved for this essential nutrient. In contrast,
some untreated lakes, even with adequate diversion of nutrients, will continue to
have algal blooms that are sustained by sediment nutrient release.
•Good candidate lakes for this procedure are those that have had nutrient
diversion and have been shown, during the diagnostic-feasibility study, to have a
high internal phosphorus release. Impoundments are usually not good candidates
because of an inability to limit nutrients. Treatments of lakes with low doses of
alum may effectively remove phosphorus (called phosphorus precipitation) but
may.be inadequate to provide long-term control of phosphorus release from lake
sediments (phosphorus inactivation).
Dissolved Inorganic phosphorus, the phosphorus form that many scientists
believe algae use for growth and reproduction, sorbs tightly to this floe. After the
floe falls to the bottom of the lake, it appears to continue to sorb phosphorus as it
slowly settles and consolidates with the sediments, and in this way acts as a
chemical barrier to phosphorus release. .
It should be clearly understood that phosphorus inactivation is not similar in
any way to an algicide treatment and should not be classified or regulated with
them. When carried out correctly (see section on Potential Negative Impacts),
phosphorus inactivation provides a nontoxic, long-term control of algae through
nutrient limitation. Algicides, on the other hand, provide only short-term control of
algae by adding a substance that is broadly toxic to many organisms in addition
to the "target" organisms.
• EFFECTIVENESS. Phosphorus inactivation has been highly effective and
long-lasting in thermally stratified natural lakes, especially where an adequate
dose has been given to the sediments and where sufficient diversion of nutrient
incomes has occurred. There has been almost no experience in using this proce-
dure in reservoirs; there it is difficult to divert nutrients, therefore treatment effec-
tiveness might be very brief. In addition, high flows may wash the floe out or
quickly cover it with another layer of nutrient-rich silt.
Successful treatments have been made to large, deep lakes as well as to the
more common smaller ones and farm ponds. Treatment longevity has extended
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beyond 10 years in some cases and to 5 ye.ars in many. Shallow, nonstratified
lakes appear to have shorter periods of treatment effectiveness than stratified
lakes. In some cases, the phosphorus-sorbing floe layer has become covered
with new, phosphorus-rich sediments. •
Typical lake responses to alum treatment include
• Sharply lowered phosphorus concentrations
• Greatly increased transparency (and improved conditions for weeds
• Algal blooms of much reduced intensity and duration.
• POTENTIAL NEGATIVE IMPACTS. The addition of aluminum salts to lakes
has the potential for serious negative impacts, and care must therefore be exer-
cised with, regard to dosage. The potential for toxicity problems is directly related
to the alkalinity and pH of the lake water. pH and alkalinity must be determined in
the diagnostic studies (see Chapter 3) before this treatment is implemented.
When alum or aluminum sulfate (Al2(S04)s • 14 HaO) is added, aluminum
hydroxide (AI(OH)3) is readily formed in water at pH 6 to 8. This compound is the
visible precipitate or floe described earlier. However, pH and alkalinity of the water
will fall during alum addition at a rate dictated by the initial alkalinity .or buffering
capacity of the water. In soft water, only very small doses of alum can be added
before alkalinity is exhausted and the pH falls below 6. At pH 6 and below,
AI(OH)2 and dissolved elemental aluminum (Ai+3) become the dominant forms.
Both can be toxic to lake species. Well-buffered, hard water lakes are therefore
good, candidates for this type of lake treatment because a large dose can be
given to the lake without fear of creating toxic forms of aluminum. Soft water lakes
must be buffered, • either With sodium aluminate or carbonate-type salts, to
prevent the undesirable pH shift arid to generate enough AI(OH)s to control phos-
phorus release. Dosage is therefore lake-specific.
Another potentially negative effect of phosphorus inactivation is the sharp in-
crease in water transparency, which may allow an existing weed infestation to
spread into deeper water.
• COSTS. Phosphorus inactivation, the addition of alum to lake sediments for
long-term control of phosphorus release, will have a high initial cost. For example,
at West Twin Lake in Ohio a 40-acre (1 6-ha) area of lake sediments was dosed
with 100 tons of alum (Cooke et al. 1982). At current prices, that would cost about
$14,000. However, labor is the real cost and is determined by the amount of
chemical to be added. More rapid, less expensive application systems have been
developed. It should be noted that phosphorus inactivation is a long-term treat-
ment so that costs are amortized. Peterson (1982a) has shown that, on this basis,
phosphorus inactivation is apparently less costly than sediment removal for
nutrient and algal control. If a dose sufficient to simply remove phosphorus from
the water column is used, initial costs could be much lower, but long-term effec-
tiveness may be sharply reduced.
Sediment Removal
• PRINCIPLE. The release of algae-stimulating nutrients from lake sediments
can also be controlled by removing the layer of the most highly enriched
materials. This may produce significantly lower in-lake nutrient concentrations
and less algal production, assuming that there has been adequate diversion or
treatment of incoming materials.
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• MODE OF ACTION. Several types of dredging equipment exist for use in
varying circumstances; a hydraulic dredge equipped with a cutterhead is the most
common choice. The cutter loosens sediments that are then transported as a
slurry of 80 to 90 percent water through a pipeline that traverses the lake from the
dredging site to a remote disposal area. Figures 6-1 and 6-2, from Barnard
(1978), illustrate the typical dredge and its side-to-side path across the lake.
Other types of dredges, including.the grab-bucket design, are used in special
situations. .
Normally, a permit from the U.S. Army Corps of Engineers will be required
before dredging can commence, even if a private lake is involved.
Figure 6-1.—Configuration of a typical cutterhead dredge (from Barnard, 1978).
DREDGE
PORT SWING WIRE
0 B (g D
WINCH
/ ADVANCE
*-SPUD (DOWN)
FRONT
B D
, WINDROW
STARBOARD SWING WIRE
Figure 6-2.—Spud-stabbing method for forward movement and resultant patterns of the cut
(from Barnard, 1978).
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• EFFECTIVENESS. Sediment removal to retard nutrient release can be'highly
effective. A good example Is that of Lake Trummen in Sweden where the upper
3.3 feet of sediments were extremely rich-in nutrients. This layer was removed, in-
creasing lake mean depth from 3.6 feet to 5.8 feet, and disposed of in diked-off
bays or upland ponds. Return flow from the ponds was treated with alum to
remove phosphorus. The total phosphorus concentration in the lake dropped
sharply and remained low for nine years (Fig. 6-3). While removing the entire
nutrient-rich layer of sediment can control algae, dredging is most frequently done
to deepen a lake or to remove and control macrophytes (see the section in this
chapter on Macrophyte Control Techniques).
TOTAL PHOSPHORUS, MG 1-1
1.0 -
0.5 -
196B
1971
1972
1973
1974
1975
1976
1977
1978
Figure 6-3.—Total phosphorus concentration in Lake Trummen, Sweden, before and after
dredging (courtesy of Gunnar Anderson, Department of Limnology, University of Lund,
Sweden). Shaded lines indicate period of dredging.
• POTENTIAL NEGATIVE IMPACTS. T^e potential for serious negative im-
pacts on the lake and surrounding area is very high. Many of these problems are
short-lived, however, and can be minimized with proper planning. Among the
most serious environmental problems is the failure to have a disposal area of
adequate size to handle the high volume of turbid, nutrient-rich water that accom-
panies the sediments. Unless the sediment water slurry can be retained long
enough for settling to occur, 'the turbid, nutrient-rich runoff water will be dis-
charged to a stream or lake. Turbidity, algal blooms, and dissolved oxygen deple-
tions may occur in the receiving waters. These problems may also develop in the
lake during the dredging operation, but this situation is usually temporary.
Finally, an analysis of the sediments for heavy metals (particularly copper and
arsenic, both of which have been extensively used as herbicides), chlorinated
hydrocarbons, and other potentially toxic materials should be carried out prior to
dredging. Special precautions, some of them expensive, will be required if these
substances are present in high concentrations. Chapter 8 describes implementa-
tion procedures and permit procedures, which are critical to the success of a
dredging project.
While the potential for negative impacts is high, proper dredge selection and
disposal area design will minimize them. ' ,
• COSTS. Sediment removal is expensive. Peterson (1981) reported a cost
range of $0.40 per cubic yard (yd3) to $23.35 yd3 ($ 1988) for 64 projects and
found that costs from $2 to $3 (in 1988 dollars) were common and could be con-
sidered "reasonable" for hydraulic dredging. Dredging costs are highly variable,
depending upon site conditions, access, nature of the sludge, and other factors.
In addition, the costs do not include disposal, transport, or monitoring. Peterson
(1982a) concludes that phosphorus inactivation is somewhat less expensive than
sediment removal as a method to control nutrient release.
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Dilution and Flushing
• PRINCIPLE. Lake waters that have low concentrations of an essential nutrient
are unlikely to exhibit algal blooms. While the ideal is to divert or treat nutrient-
rich waters before they empty into the lake, it is possible to lower the concentra-
tion of nutrients within the lake and flush out algal cells by adding sufficient
quantities of nutrient-poor water (dilution) from some additional source. High
amounts of additional water, whether low in nutrients or not, can also be used to
flush algae out from the lake faster than they grow.
• MODE OF ACTION. Phosphorus is often the nutrient that limits algal growth.
Its concentration in lake water is a function of its concentration in incoming water,
the flushing rate or residence time of the lake, and the net amount lost to the sedi-
ments as particles settle during water passage through the system. When water
low in phosphorus is added to the inflow, the actual phosphorus loading will in-
crease, but the mean phosphorus concentration will decrease, depending upon
initial flushing rate and inflow concentration. Concentration will also be affected
by the degree to which loss of phosphorus to sediments decreases and counters
the dilution. Lakes with low initial flushing rates are poor candidates because in-
lake concentration could increase unless the dilution water is essentially devoid
of phosphorus (Uttormark and Hutchins. 1980). Internal phosphorus release
could further complicate the effect.
Dilution also washes out cells. These facts point put the need for a water and
nutrient budget, as well as a study of basin volume, before prescribing a proce-
dure such as this one.
Flushing can control algal biomass by cell washout; however, the flushing rate
must be near the cell growth rate to be effective. Flushing rates of 10 to 15 per-
cent of the lake volume per day are believed to sufficient.
• EFFECTIVENESS. Very few documented case histories of dilution or flushing
exist, in part because additional water is not often available, especially water.that
is low in nutrients. The best documented case of dilution is that of Moses Lake,
Washington (Welch and Patmont, 1980; Cooke et al. 1986), where low-nutrient
Columbia River water was diverted through the lake. Water exchange rates of 10
to 20 percent per day were achieved, and in transparency and algal blooms
dramatically improved, illustrating the effectiveness of this method.
• POTENTIAL NEGATIVE IMPACTS. Outlet structures must be capable of han-
dling the ad'ded discharge; also, the increased volume released downstream
could have negative effects. Water used for dilution or flushing should be tested
before it is introduced to the lake to be sure that no toxics are present.
! ' .
• COSTS. Costs will vary greatly from site to site, depending upon the need for
pumps, extensive engineering, outlet structure repair, and the proximity of the
new water.
it
126
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Algae — Additional Procedures
for Control
None of these techniques is considered completely ineffective; however, none is
well enough understood or has produced enough positive results to be con-
sidered an established and effective long-term procedure.
Artificial Circulation
Artificial, circulation eliminates thermal stratification or prevents its formation,
through the injection of compressed air into lake water from a pipe or ceramic dif-
fuser at the lake's bottom (Fig. 6-4). The rising column of bubbles, if sufficiently
powered, will produce lakewide mixing at a rate that eliminates temperature dif-
ferences between top and bottom waters. Algal blooms may be controlled, pos-
sibly through one or more of these processes:
1. In light-limited algal communities, mixing to the lake's bottom will increase
a cell's time in darkness, leading to reduced net photosynthesis.
2. Introduction of dissolved oxygen to the lake's bottom may inhibit
phosphorus release from sediments, curtailing this internal nutrient source.
3. Rapid circulation and contact of water with the atmosphere, as well as the
introduction of carbon dioxide-rich bottom water during the initial period of
mixing, can increase the water's carbon dioxide content and lower pH,
leading to a shift from blue-green algae to less noxious green algae.
4. When zooplankton that consume algae are mixed to the lake's bottom, >.
they are less vulnerable to sight-feeding fish. If more zooplankters
survive, their consumption of algal cells may also increase.
Results have varied greatly from case to case. In most instances, problems
with low dissolved oxygen (which can occur with deep discharge dams, for ex-
ample) have been solved. In about half the cases, and where very small tempera-
ture differences from top to bottom have been maintained all summer, algal
blooms have been reduced. In other cases, phosphorus and turbidity have in-
creased and transparency has decreased. When artificial circulation is properly
used in a water supply reservoir, problems with iron and manganese can be
eliminated.
Failure to achieve the desired objective may be caused by lake chemistry or
equipment. Lorenzen and Fast (1977) concluded that to adequately mix a lake,
an air flow of about 1.3 cubic feet per minute (1.3 ft3/min) per acre of lake surface
is required to maintain oxygen within the lake. Underdesign is a major cause of
failure for this technique. This is a highly specialized area; therefore, the system
should be designed by a professional who is experienced in artificial circulation.
Correct air flow pressure depends on site conditions. Algae control may also
depend on a particular lake's water chemistry, including its pH and alkalinity.
Costs are low and will primarily be for the compressor and installation of pipes
and diffuser. •
127
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Hypolimnetic Aeration
Hypolimnetic aeration is different from artificial circulation in both objective and
operation. While artificial circulation injects compressed air from a diffuser located
on the lake bottom, hypolimnetic aeration most commonly employs an airlift
device to bring cold hypolimnetic water (the deep, stagnant water layer) up to the
surface of deep lakes. The water is aerated by contact with the atmosphere,
some gases such as carbon dioxide and methane are lost, and then the water is
returned to the hypolimnion (Fig. 6-5). Thereiis no intention to destratify the lake.
Figure 6-4.—Destratlflcatlon system installed.at El Capitan Reservoir, California (from Loiren-
zen and Fast, 1977)
A common use of this procedure is to maintain a cold .water fishery in a lake
where the hypolimnion is normally oxygen-free. Another use is to eliminate taste
and color problems in untreated drinking water withdrawn from a hypolim-
nion. This is done by introducing oxygen, which will produce chemical conditions
that will favor precipitation of iron and manganese, the elements most often as-
sociated with color in drinking water. Also, the procedure could be used to im-
prove the quality of water discharged downstream from a hypolimnetic discharge.
There is little documentation of its successful use in controlling nuisance
algae, although there is evidence that hypolimnetic aeration can control phos-
phorus release from lake sediments by promoting its combination with iron. Iron
additions to the hypolimnion during aeration could enhance phosphorus removal
and thereby control internal phosphorus release. Hypolimnetic aeration could be-
come a type of phosphorus inactivation procedure under high oxygen, high iron
conditions, and in this way may promote some control of algae. A case history
describing use of hypolimnetic aeration to effectively improve raw drinking water
and reduce algal abundance is given by Walker et al. (1989).
Hypolimnetic aerators need a large hypolimnion to work properly; consequent-
ly, any use of these aerators in shallow lakes and reservoirs should be.done
cautiously, if at all.
128
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Figure 6-5.—Aqua Technique's Limno partial air-lift hypolimnetic aerator. The arrows indicate
the direction of airflow. (Courtesy of Aqua Technique.)
Costs of hypolimnetic aeration are dictated by the amount of compressed air
needed (a function of hypolimnioh area, the rate of oxygen consumption in the
lake, and the degree of thermal stratification). A procedure for calculating this is
presented in Kortmann (1989).
Hypolimnetic Withdrawal
The cold, deep layers of a thermally stratified eutrophic lake or reservoir may
have higher nutrient concentrations than upper layer waters. Any vertical entrain-
ment of this water to the epilimnion will introduce nutrients to it and possibly trig-
•ger an algal bloom. This can happen naturally during the passage of a cold front
and during spring and fall turnover periods. The objective of hypolimnetic
withdrawal is to remove this nutrient-rich,, oxygen-free water either through a
129
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deep^outlet in the dam or by a siphon, thereby accelerating the lake's phosphorus
loss knd perhaps producing a decrease in phosphorus concentration in surface
waters. There are,' however, few documented case histories of this procedure
(Nurnberg, 1987).
Serious negative impacts are possible. The discharge.water may be of poor
quality and therefore may require aeration or other treatment. State or Federal
regulatory agencies may require a permit to discharge this water. Also, hy'polim-
netic withdrawal could produce thermal instability and thus destratification that
could introduce nutrient-rich, anoxic water to the epilimniori, triggering an algal
bloom. However, it is unlikely that there would be negative effects to biota.
Costs should be comparatively low and would involve a capital outlay for
pump, pipe, and an aeration device. .
Sediment Oxidation
This is a recent and highly experimental procedure (Ripl, 1976). The procedure's
goal is to decrease phosphorus release from sediments, as with phosphorus in-
activation. If sediments are low in iron, ferric chloride is added to enhance phos-
phorus precipitation. Lime is also added to bring sediment pH to 7.0-7-5, the op-
timum pH for denitrification. Then calcium nitrate is injected into the top 10 inches
of sediments to promote the oxidation or breakdown of organic matter and
denitrification. The entire procedure is often called RIPLOX after its originator, W.
Ripl.
Lake LJllesjon, a 10.5-acre Swedish lake with a 6.6 foot mean.depth, was the
first to be treated. The procedure cost $112,000, primarily for equipment develop-
ment and the preliminary investigation; chemical costs were about $7,000. The
treatment lowered sediment phosphorus release dramatically and lasted at least
two years. A portion of a Minnesota lake was also treated, but high external load-
ing overwhelmed the effects. No negative impacts have been reported, however.
Food Web Manipulation
Shapiro et al. (1975)' were the first to suggest a group of procedures', called
"biomanipulation," that they believed could greatly improve lake quality without
the use of expensive machines and chemicals. The following paragraphs
describe their ideas. •
In some lakes the amount of algae in the open water is controlled at times by
grazing zooplahkton rather than by the quantity of nutrients. Zooplankters are
microscopic, crustacean animals found in every lake that can, as a community of
several species, filter up to the entire epilimnion each day during the summer as
they graze on algae, bacteria, and bits of organic matter. .
The most efficient zooplankton grazers—that remove more particles over the
widest range of particle sizes—are the largest-sized species. In some lakes, such
as subtropical lakes in Florida, the large-bodied zooplankton species do not
occur. In other lakes, large zooplankton are preferentially eaten by certain fish, in-
cluding the fry of nearly every fish species and the adults of bluegill, pumpkin-
seed, perch, shad, and others. In lakes dominated by adults of carnivorous
species such as largernouth bass, walleye, and northern pike, large-bodied
zooplankton are more likely to survive because the populations of their predators
have been reduced. Abundance of some species of algae will thus be reduced
because grazing zooplankters can proliferate under these circumstances. Con-
versely, grazing on algae may be severely reduced in lakes dominated by
zooplankton-eating'fish, and thus there could be more extensive algal.blooms.
130
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Ttiis type of algal control by animals in the food chain is "top-down" control and
differs from our usual conception of "bottom-up" algal control through nutrient
limitation: Figures 6-6 and 6-7 are pictorial models of these food web interactions.
The density of zooplankton-eating fish can be reduced through the use of fish
poisons, water level drawdown, winterkill, or by limiting them by stocking pred-
PISCIVOROUS
FISH
1-2 FT
CAT ^
CM I A'"
PLANKTIVOROUS
FISH
y
EAT
6"-1 FT
ZOOPLANKTON
y
1/10 IN
EAT '^^^
ALGAE
y
MICROSCOPIC
NUTRIENTS
NUTRIENTS
A
RECYCLE
A
A
BENTHIC
ORGANISMS
Figure 6-6.—The aquatic food chain.
131
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Comparison of Top-down Effects on Food Chain [
Low predator biomass
High zooplankton
feeders biomass
Low zooplankton
biomass
High phytoplankton
biomass
• Low Secchi depth
• HighpH '
• Stressed 02 supply
High predator biomass
Low zooplankton
feeders biomass
High biomass of
large-bodied zooplankton
Role of
carnivorous
zooplankton
uncertain
Low biomass
Possibly high i
of small j | biomass of j Role of
I I
phytoplankton | large, colonial
\r&. O*-fJ O ! I Vikn/t/itilanL-trtn!
11 phytoplanktoni
nutrient load
and
hydrophysical
conditions
uncertain
• High Secchi depth
• Normal or high pH
• Normal or .extreme
values
Figure $-7.—Hypothetical scheme showing the connections involved In biomanipulatlon.
132
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atbry fish. However, addition of predators, such as walleyes, may not produce
any measurable "top-down" control of algae when nutrient loading is high or
when the algae are dominated by inedible species, such as certain blue-green
algae. Allowing anglers to remove stocked predatory.fish may make little
ecological sense where clear water is desired. It also makes poor ecological
sense to stock a lake with zooplankton-eating fisfi (such as gizzard shad)
when clear water is a management goal. However, in lakes where sport fishing
is the first priority, a planktivorous fish such as the gizzard shad is an essential
foodweb link between production occurring at lower and higher trophic, levels
(see Fig. 2-10). The beneficial effects of controlling the density of stunted pan-
fish are strong enough, nevertheless, to warrant these lake management
projects, especially on small lakes.
Other conditions that might affect the population of zooplankton grazing on
algae include an oxygen-free hypolimnion, common in eutrophic lakes, that
eliminates this zone as a daytime refuge of zooplankton from sight-feeding fish
and thus enhances zooplankton mortality. An aeration device might eliminate
this problem. Another cause of zooplankton mortality is the toxic effects of pes-
ticides that enter the lake with agricultural runoff. The use of copper sulfate for
temporary algal control can also produce significant zoopianktan mortality at
doses far below those needed for algae. Severe mortality of zooplankton could
explain the common "rebound" of algae following a copper treatment Figure 6-
7, from Benndorf et al. (1984), summarizes food web management.
Yet another type of biomanipulation that could improve lake transparency is
elimination of fish such as the common carp or bullheads that are bottom brow-
sers. Browsing has been shown to release significant amounts of nutrients to
the water column as these fish feed and digest food. Removing such fish, how-
ever, is exceedingly difficult since they tolerate very low levels of dissolved
oxygen and high doses of fish poisons.
Costs of biomanipulation are hot known. Fish poisons are expensive and in
many cases would entaij an expensive cleanup of dead fish. The cost of
restructuring a food web through enhancement of a predatory fish population
will, of course, be specific to each lake. Because of the high interest in fish and
fishing at most lakes, significant volunteer labor and expertise might be avail-
able. State fish and game personnel would be an excellent resource for stock-
ing densities and species likely to survive in any given area.
Algicides
Copper sulfate (CuSCU) is the most widely employed algicidal chemical. It is
registered for use in potable waters, although restrictions apply in some
States. Simazine is also extensively used to control algae.
Cbpper inhibits algal photosynthesis and alters nitrogen metabolism. In
practice, copper sulfate is applied by towing burlap or nylon bags filled with
granules (which dissolve) behind a boat. In alkaline waters (150 mg CaCOa
(calcium carbonate) per liter, or more) or in waters high in organic matter, cop-
per 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. Both planktonic
algae, including nuisance blue-green species, and species forming filamen-
tous mats in weed beds or on the bottom will be killed by doses.of 1-2 mg
CuSCWL (0.8 milligrams of copper per liter (mg Cu/L)). A review of dose, effec-
tiveness, and environmental impacts is found in Cooke and Carlson (1989).
133
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Copper sulfate Is often effective, although the response may be brief and
require additional applications. There are several undesirable impacts, and it is
not a lake restoration agent since no causes of the problem are addressed.
Negative impacts include toxicity to fish and dissolved oxygen depletions when
overly large areas are treated within a short period of time. Hanson arid Stefan
(1984) report that 58 years of copper sulfate use in a group of Minnesota lakes,
while effective at times for the temporary control of algae, appears to have
produced dissolved oxygen depletions, increased internal nutrient cycling, oc-
casional fishkills, copper accumulati'on in sediments, increased tolerance to
copper by some nuisance blue-green algae, and undesirable effects to fish and
the fish-food community. They conclude that short-term control (days) of algae
has been traded for long-term degradation of the lakes.
Costs of algicides are related to dose, to longevity of effect, and to ap-
plicator fees. The usual dose of granular copper sulfate for control of planktonic
algae is about 5.4 pounds per acre-foot of water. An acre-foot is an acre of
water 1 .foot deep. The most commonly used chelated products are applied at
0.6 gallons per acre-foot. Current prices for chemicals are about $6 per acre-
foot for granular copper sulfate at a dose of 5,4 pounds per acre-foot, and $22
per acre-foot of a chelated product at a dose of 0.6 gallons per acre-foot. Ap-
plication procedures are more rapid for the liquid chelated form, and there have
been claims that its effect on algae will last longer than granular copper sulfate,
suggesting that annualized costs for use of the chelated form, especially in
hard water lakes, may be similar to the granular form. Fees of the licensed, in-
sured applicator are not included here.
Algae—Summary of Restoration
and Management Techniques
Table 6-1 summarizes the procedures described in the preceding sections;
Qualitative evaluation of the procedures with regard to short- and long-term ef-
fectiveness, costs, and potential negative impacts are presented. These judg-
ments are the consensus of a panel of 12 lake and reservoir restoration ex-
perts." ' •
Table 6-1.—Comparison of lake restoration and management techniques for
control of nuisance algae.
TREATMENT (ONE APPLICATION)
Phosphorus Inactivation
Dredging
Dilution
Flushing
Artificial Circulation
Hypolimnetic Aeratipn
Sediment Oxidation
Algicides
Food Chain Manipulation
Rough Fish Removal
Hypolimnetic Withdrawal
SHORT-
. TERM
EFFECT
E
• F'
G
F
G
F
G
G
?
G
G
LONG-
TERM
EFFECT
• E
E
G
F
?
?
E
P
?
P
G
COST
G
P
F
F
G
G
F .
G
E
E
G
CHANCE OF
NEGATIVE
EFFECTS
L
F
L
L
F
F
• ?
H
?
? .
F
E « Excellent F - , Fair
G = Good P = Poor
H - High L = Low
134
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Problem II: Excessive
Shallowness
The incomes of silt and organic matter from agricultural erosion, construction,
shoreline collapse, urban drainage, and other sources can rapidly increase the
area of very shallow water. Not only can this interfere with recreational ac-
tivities such as boating, but shallow, nutrient-rich sediments are ideal areas for
growth of nuisance aquatic plants.
Sediment removal, outlined earlier in this chapter^ is the only practical way
to bring about lake or reservoir improvement when shoaling is a problem.
Therefore, dredging has become one of the most frequently prescribed tech-
niques. A properly designed feasibility study of the lake and disposal sites is an
essential first step, and, in nearly all cases, a permit from the U.S. Army Corps
of Engineers will be required. Dredging projects are expensive and can have
severe negative impacts unless correctly designed, but they are often highly
effective. Continual incomes of silt will return the lake to its predredged condi-
tion; therefore, silt sources should be controlled. The reader is referred to
Cooke et al. (1986), Cooke and Kennedy (1989) and Cooke and Carlson
(1.989) for detailed descriptions about dredge selection, disposal area design,
and case histories. .
Problem III: Nuisance Weeds
(Macrophytes)
Biology of Macrophytes
Overabundant rooted and floating plants are a major nuisance to lake and
reservoir users. In extreme cases, particularly in ponds and in shallow, warm,
well-lighted lakes and waterways of the southern United States, weeds (some-
times called macrophytes) can cover the entire lake surface. Weeds obviously
interfere with recreation and detract from a lake's aesthetic values. They can
also introduce significant quantities of nutrients and organic matter to the water
column, perhaps stimulating algal blooms and raising dissolved oxygen con-
sumption.
Macrophytes are generally grouped into classes called emergents (repre-
sented by alligatorweed and cattails), floating-leaved (water hyacinth and
water lilies), and submergents (hydrilla and pondweeds), plus the mats of
filamentous algae that develop in weed beds. Understanding the factors that
control weed growth is the first step in controlling weeds.
Macrophytes reproduce both by producing flowers and seeds and by
asexual propagation from fragments and shoots extending from roots. Growth
rates of macrophytes, especially exotic species like water hyacinth, hydrilla,
and milfoil, can be very high.
Submergent plants will grow profusely only where underwater illumination
is sufficient. Steep-sided lakes therefore support a much smaller development
of common nuisance weeds because most of the sediments are too dark or too
deep. Similarly, turbid lakes and reservoirs are unlikely to have dense beds of
submerged plants. Thus, high silt incomes to a lake can create a favorable
135
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weed habitat as the lake fills in., unless the silt loading also creates severe tur-
bidity. Significant reductions in algal blooms can also enhance light penetration
and allow weeds to grow better.
Since most macrophytes obtain their nutrients via roots, they can therefore
be abundant in lakes in which nutrient concentration of the water column has
been reduced through diversion. When the sediments are either highly organic.
or inorganic (sand), macrophyte growth may be poor because it is more difficult
for roots to obtain nutrients in these sediment types. In these two extremes,
emergent plants may replace submergents because their more extensive root
systems are better adapted to these conditions.
Texas, Louisiana, Alabama, Georgia, and especially the sub-tropical en-
vironment of Florida have lakes, reservoirs, ponds, waterways, and streams
that are infested with exotic plants such as^hydrilla, water hyacinth, and al-
ligatorweed—plants that are severe economic and recreational-nuisances. In
Florida, plants grow throughout most of the year, often at incredible rates, so
dense amounts of plants will be found. Aquatic plant management in these
ecosystems often requires methods that might seem extreme in northern
ecosystems.
No native animals have been found that graze on macrophytes at rates suf-
ficient to control them. Biological controls, therefore, are.confined to exotic
animals.
For years macrophytes have been managed through cutting or herbicides.
The development of alternative procedures to produce long-term control has
lagged far behind, in part because we have, until recently, understood very little
about macrophyte physiology and the environmental factors that control their
growth. The following paragraphs briefly describe the procedures known to
produce long-term control. Since short-term management techniques are likely
to continue to be used, for example in southern waters or during implernenta-
tion of a longer-term treatment, these are described in a separate section.
Macrophytes—Long-Term
Control Techniques
Sediment Removal and Sediment
Tilling
• PRINCIPLE. Sediment removal can limit submerged weed growth through
deepening, thereby limiting light, or by removing sediments favorable to growth
and leaving sand. Both dredging and rototilling.remove roots and thereby limit
plant growth. : '
• MODE OF ACTION. Sediment removal was described in some detail in ear-
lier paragraphs on algal control. The amount of sediments removed, and hence
the new depth and associated light penetration, is critical to successful long-
term control of rooted, submerged plants. There appears to be a direct relation
between water transparency, as simply determined with a Secchi disk, and the
maximum depth of colonization .(MDC) by macrophytes. Canfield et al. (1985)
provide.these equations to estimate MDC in Florida and Wisconsin from Sec-
chi disk measurements:
136
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STATE EQUATION
Florida log MDC = 0.42 log SD + 0.41
Wisconsin - log MDC = 0.79 log SD + 0.25
where SD = Secchi depth in meters
«•• ' '
For example, suppose the Secchi transparency of a Florida lake is usually
about 6 feet. How far from shore can we expect to find rooted macrophytes
(the MDC)? A handheld calculator can be used to obtain the answer, which will
suggest how deep nearshore areas would have to be to have minimal quanr
titles of rooted, submerged macrophytes. In this case, transform 6 feet to
meters (feet x 0.305 = meters). This will be 1.83 meters. The log of'1.83 is
0.26. Then substitute this in the equation for a Florida lake, as follows:
log MDC = (0.42 x log 1.83) + 0.41
= (0.42 x 0.26) + 0.41
'. . = 0.52
To obtain depth (MDC) in meters use the calculator to find the antilog of
0.52 = 3.31 meters. To convert meters to feet, multiply this answer.by 3 28 =
10.9 feet. This means that for a Florida lake with a Secchi disk transparency of
about 6 feet, we would expect some submerged weeds in 11 feet of water and
more weeds in progressively shallower water. In this example, very large
amounts of sediments might have to be removed to create large areas of the
lake with depths of 10 to 11 feet. Examination of a bathymetric map (see Fig.
3-9) will indicate whether this is the case. The equation also indicates that ac-
tions that greatly improve water clarity, such as erosion control or phosphorus
inactivation, may enhance weed distribution and abundance. This may be par-
ticularly true in the case of hydrilla, a nuisance exotic plant in southern waters.
Hydrilla can grow at lower light intensities than native plants, making control
through deepening an expensive and perhaps impossible task.
Rototilling and the use of cultivation equipment are newer procedures
presently under development and testing by the British Columbia Ministry of
Environment (Newroth and .Soar, 1986). A rototiller is a barge-like machine with
a hydraulically operated tillage device that can be lowered to depths of 10 to
12 feet (3 to 4 meters) for the purpose of tearing out roots. Also, if the water
level in the lake can be drawn down, cultivation equipment pulled behind trac-
tors on firm sediments can achieve 90 percent root removal.
• EFFECTIVENESS. The use of sediment removal for long-term control of
macrophytes is effective when the source of sediments is controlled. Dredging
below the lake's photic zone will prevent macrophyte growth. The cost of
dredging, however, often places the use of this technique in doubt. Rototilling
to remove watermilfoil may be as effective as three to four harvesting opera-
tions.
• POTENTIAL NEGATIVE IMPACTS. The negative impacts of sediment
removal have already been discussed under algal control.
• COSTS. Costs were described earlier under algal control. Newroth and
Soar (1986) have studied costs of the rototiller and amphibious cultivator and
found them to be similar to herbicides and harvesting, but operation speed is
slower. •
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Water Level Drawdown
m PRINCIPLE AND MODE OF ACTION. Exposing sediments to prolonged
freezing and drying provides an opportunitylo carry out several management pro-
cedures. Some rooted plant species are permanently damaged by these condi-
tions and the entire plant, including roots and perhaps seeds, is killed if exposed
to freezing for two to four weeks. Other species, however, are either unaffected or
enhanced. Drawdown also allows repair of dams and docks, fish management,
sediment removal, and installation of sediment covers to control plant growth.
• EFFECTIVENESS. Cooke et al. (1986) summarize the responses of 74
aquatic plants to drawdown. Table 6-2 lists the responses of sonhe common
species. :
Many case histories exist, and they illustrate three important facts:
1. Freezing and desiccation are required; wet, cold lake sediments or wet
sediments covered with snow may have little negative effect on plants.
2. The technique is species-specific.
3. Successful drawdown-freezing operations should be alternated every two
years with no drawdown so that resistant species do not become firmly
established.
Table 6-2.—Responses of common aquatic plants to drawdown
DECREASE .
Coontail (Ceratophyllum demersum) \^g*
Brazilian elodea (Elodea = Egeria densa) , . /•••
Milfoil (Myriophyllum spp.) . 'IBP
Southern naiad (A/a/as guadalupensis) ^^r
Yellow Water Lily (Nuphar lutea)
Water Lily (Nymphaea spp.) .
Bobbin's Pondweed (Potamogeton robbinsii)
INCREASE
Alligator Weed (Alternanthera philoxeroides) . :
Hydrilla (Hydrilla verticillata)
Bushy Pondweed (Najas flexilis)
VARIABLE .
Water Hyacinth (Eichhomia crassipes)
Common Elodea (Elodea canadensis)
Cattail (Typha latifolia) •
Two case histories illustrate these points. Beard (1973) describes winter draw-
down of Murphy Flowage, Wisconsin. Before drawdown, 75 acres were closed in
spring and summer to fishing because of a dense infestation of pondweeds
(Potamogeton robbinsii, P. amplifolius), coontail, Eurasian watermilfoil, and water
lily. Drawdown opened 64 acres, and although some resistant plants increased,
fishing improved. Geiger (1983) used winter drawdown in an attempt to control
Eurasian watermilfoil in an Oregon lake. The mild, wet winter of the Pacific
Northwest did not provide sufficient freezing; the weeds increased and had to be
treated with 2,4-D. . .
• POTENTIAL NEGATIVE IMPACTS. Algal blooms have'occurred after some
drawdowns. The causes are unclear but may be, related to nutrient release from
sediments or to an absence of competition from weeds. The most significant
problem with drawdown can be loss of use of the lake.
138
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Drying and freezing can sharply reduce the abundance of benthic inver-
tebrates essential to fish diets. Also, oxygen can be.depleted in the remaining
water pool can occur, leading to a fishkill. Dissolved oxygen should be
monitored in small-volume systems, and an aerator should be installed if
needed.
• COSTS. If the lake is controlled by a dam with drawdown capability, expen-
ditures will be minimal. Additional costs are associated with losing the use of
the lake. : :
Shading and Sediment Covers
The use of dyes in the water and coverings on the water surface to limit the
light available to plants and .the. application of plastic sheets over the sedi-
ments to stop plant growth are prompted by the well-known facts that rooted
plants require light and cannot grow through physical barriers. Applications of
silt, sand, clay, and gravel have also been used, although plants sooner or
later can root in them. , , .
Sediment covering materials, such as polyethylene, polypropylene,
fiberglass, and nylon can be used in small areas such as dock spaces and
swimming beaches to completely terminate plant growth. Large areas are not
often treated because the costs of materials and application are high.
• EFFECTIVENESS. Engel (1982) lists the advantages of sediment covers
according to their use: -
1. Use is confined to a specific area. ,
2. Screens are out of sight and create no disturbance on shore.
3. They can be installed in areas where harvesters and spray boats
cannot reach. , • .
4. No toxics are used.
5. They are easy to install over small areas.
And these disadvantages:
1. They do not correct the cause of the problem.
2. They are expensive.
3. They are difficult to apply over large areas or over obstructions.
4. They may slip on steep grades or float to the surface after trapping .
gases beneath them.
5. They can be difficult to remove or relocate.
6. They may tear during application.
7. Some materials are degraded by sunlight.
8, A permit may be required.
139
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Successful use is related to selection of materials and to the quality of the
application. The most effective materials are gas-permeable screens such as
Aquascreeh (fiberglass), polypropylene, Dartek (nylon), and to a lesser extent,
common burlap. Polyethylene and synthetic rubber trap gases beneath them.
Proper application requires that the screens be placed flush with the sediment
surface and staked or securely anchored. This is difficult to accomplish over
heavy plant growth, therefore spring or winter drawdown are ideal times for ap-
plication. Scuba divers apply the covers in deep water, which greatly increases
costs. Depending upon siltation rate, sediment covers will accumulate
deposits, which allows plant fragments to root. Screens then must be removed
and cleaned. .
Surface shading has received little attention. 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 were sufficient to eliminate all
species of Potamogeton for the summer if the sheets were applied in spring
before plants grew to maturity. Coontail. was also controlled but Chara was not.
This procedure may be a useful alternative to traditional methods of weed con-
trol in small areas such as docks and beaches.
Dyes have been applied to small areas such as ponds to light-limit algae
and weeds.
• POTENTIAL NEGATIVE IMPACTS. Negative features of sediment covers
appear to be few. Benthic invertebrates may be eliminated (Engel, 1982), but
dissolved oxygen depletions have not been a problem.
• COSTS. Table 6-3, modified from Gooke'and Kennedy (1989), summarizes
costs of some sediment-covering materials. These costs do not include ap-
plication fees.
Table 6-3.—Characteristics of some sediment covering material (revised from
Cooke and Kennedy. 1989).'
SPECIFIC
MATERIAL GRAVITY
1.
2.
3.
4.
5.
6.
Black .
Polyethylene
Polypropyl
(Typar)
Fiberglass-
PVC (Aqua-
screen)
Nylon
(Dartek)
Burlap
i
Nylon-
Silicone
0.
0.
2.
•1.
1.
95
90
54
0
,0
1.5
$1,
$3
S8
S3
$1
$65
APPLICATION
COST -DIFFICULTY
,860 acre
.240 acre
.700 acre
.240 acre
.375 acre
.475 acre
High
Low
Low
Moderate
Moderate
. 7
GAS
PERMEABILITY
Impermeab.le
Permeable
Permeable
Impermeable
Permeable
Impermeable
COMMENTS
Poor choice of
materials, easily
dislodged:
"balloons"
Effective
,
Effective
Effective if vented
Effective up to 1
season! rots
Must be installed
by dealer
140
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Biological Controls
*
*
• PRINCIPLE. Significant improvement in our future ability to achieve lasting
control of nuisance aquatic, vegetation in many areas of North America may
come from use of plant-eating or plant pathogenic biocontrol organisms or
from a combination of current procedures such as harvesting, drawdown, and
herbicides with these organisms. Biological control has the objective of achiev-
ing long-term control of plants without introducing-expensive machinery or
toxic chemicals.
• MODE OF ACTION
GRASS CARP (Ctenopharyngodon idelia Val.): Grass carp are an exotic
fish (imported originally from Malaysia to the United States in 1962) known
to be voracious consumers of macrophytes. They have very high growth
rates (about 6 pounds, or 2.5 kg per year at the maximum rate; Smith and,
Shireman, 1983).'This combination of broad diet and high growth rate can
produce control, or more likely, eradicate the plants within several seasons.
Grass carp do not consume aquatic plant species equally readily.
Generally, they avoid alligatorweed, water hyacinth, cattails, spatterdock,
- and water lily. The fish prefer plant species that include elodea, pondweeds •
(Potamogeion spp.), and hydrilla. Low stocking densities can produce selec-
tive grazing on the preferred plant species while other less preferred
species, including milfoil, may even increase. Overstocking, on the other
hand, will eliminate the weeds, Feeding preferences are listed in Nail and
Schardt (1980), Van Dyke etal. (1984), and Cooke and Kennedy (1989).
INSECTS: Ten insect species have been imported to the United States
under quarantine and have received U.S. Department of Agriculture apr
proval for release to U.S. waters. These insects are confined to the waters
of southern States, specifically to control alligatorweed and water hyacinth.
At present, neither exotic nor native insects are used against northern
plants.
These 10 species have life histories that are specific to the host plants
and are therefore confined in their distribution to infested areas. They are
also climate-limited to southern States, with the northern range being Geor-
gia and North Carolina. .
Their reproductive rates are slower than their target plants. Therefore,
control is slow, although it can-be enhanced by integrated techniques where-
in plant densities are reduced at a site with harvesting or herbicides, and in-
sects are concentrated on the remaining plants. '
• EFFECTIVENESS ~
GRASS CARP: Grass carp are used in several States (for example,
Florida, Texas, Arkansas), although they remain banned for public and
private use in many others. They are undergoing a thorough evaluation
throughout the United States, especially the sterile triploid variety. Most
studies have found that the fish are exceptionally effective in reducing or
eliminating nuisance vegetation, although there have been undesirable side
effects. Two case histories illustrate their use.
Martyn et al. (1986) described the introduction of diploid (able to
reproduce) grass carp into Lake Conroe, Texas, a water supply impound;
ment for Houston. Submersed weeds occupied about 44 percent of the
141
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20,000 acres at-maximum infestation. Most plants were hydrilla (Hydrilla ver-
ticillata), although milfoil and coontail were also abundant. Between Septem-
,ber 1981 and September 1982, 270,000 grass carp, 8 inches or longer, were
introduced. By October 1983, all submersed plants were gone. Associated
with this eradication was an increase in planktonic algae, a decrease in
transparency, and an increase in open-water fish species associated with
plankton. Fish associated with weed beds declined.
Van Dyke et al. (1984) studied the effects of diploid grass carp stocking in
three central Florida lakes and one reservoir. Hydrilla was eliminated for six
years and may have been eradicated from the lakes. Few rooted plants
remain. Illinois pondweed (Potamogeton illinoiensis) was eliminated from the
reservoir, and milfoil was greatly reduced. Control in all four sites was slowly
achieved but has been long-lasting. Eurasian watermilfoil has returned to the
reservoir, apparently because the carp escaped.
Grass carp have not bedn successful weed management agents in the
• sense that small numbers could be stocked to achieve a partial elimination of
plants. Shireman et al. (1983) attempted to do this in Lake Pearl, Florida, by
stocking carp at low densities and using some herbicides on an infestation of
hydrilla. Carp were stocked at increasing rates over a two-year period while
herbicide additions continued. After two years, a carp density was finally
reached that had an impact on the plants, and then eradication occurred.
Stocking rates appear to vary geographically, with the type, diversity, and
coverage of plants, and with the management goal. A detailed discussion of
stocking rates and food preferences is found in Cooke and Kennedy (1989);
State fisheries personnel can also be an excellent source of information.
Lake homeowners and managers are strongly advised not 'to stock a lake
unless competent technical advice about the specific lake has been ob-
tained. State fisheries personnel should be contacted prior to stocking be-
cause this practice is not legal in all States (see Table 6-4).
Table 6-4.—State regulations on possession and use of grass carp (modified from
Allen and Wattendorf, 1987)
A. Diploid (able to reproduce) arid Triploid (sterile) permitted
Alabama • Hawaii Kansas . Oklahoma
Alaska iowa , Mississippi New Hampshire
Arkansas Idaho Missouri Tennessee '
B. Only 100% Triploids permittee!
California . Illinois New Jersey South Carolina
Colorado Kentucky New Mexico South Dakota
Florida ' Montana North Carolina Virginia
Georgia Nebraska . Ohio WestVirginia
C. 100% Triploids permitted for research only
New York Louisiana Oregon Wyoming
D. Grass Carp prohibited
Arizona Maryland North Dakota Utah
Connecticut Massachusetts Pennsylvania Vermont
Delaware Michigan Rhode Island Washington
Indiana Minnesota Texas ' Wisconsin
• Maine Nevada .
142
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INSECTS: Insects have'proven to be highly effective in controlling alligator-
weed and water hyacinth. For example, Sanders and Theriot (1986) report
that the water hyacinth weevil (Neochetina eichhorniae) has been respon-
sible for at least a 50 percent decrease in the water hyacinth distribution in
Louisiana since 1974. Insect control has been particularly effective when
combined with another plant management technique. Two case histories il-
lustrate this point. .
Center and Durden (1986) studied the effect of the water hyacinth weevil
in a Florida canal. When a canal section was harvested at the peak of the
growing season, both water hyacinths and weevils were severely reduced.
Subsequent plant growth was much greater than the weevil population, and
control was greatly delayed. Another section was sprayed with 2,4-D at
season's end, allowing plants and weevils to recover simultaneously. Insect
control occurred more rapidly. Chemical or mechanical control, along with in-
sects, will be more effective if done in early fall or winter to minimize inter-
ference with the insect.
' Haag (1986) studied a Florida pond completely covered with water
hyacinth. Weevils (N. eichhornia and N. bruchi) were present in small num-
bers! About 20 percent of the pond was. isolated with a barrier while the rest
was sprayed with 2,4-D in monthly increments of 25 percent of the remaining
pond area. Weevil density slowly increased in the isolated area and by the
following year exerted 100 percent control, of water hyacinth in the entire
pond. Eradication allowed alligatorweed to invade, but its spread was check-
ed by the alligatorweed flea beetle, Agasicles hygrophila.
This work supports the conclusion that weed eradication with herbicides,
a common strategy, will also eliminate the insects and allow a prompt return
of the weeds. By leaving a reservoir of weeds and by "herding" the insects to
it, sufficient insect density is achieved to produce longer-term weed control.
POTENTIAL NEGATIVE IMPACTS
GRASS CARP: Grass carp can produce a major change in the structure of
a lake. When these fish are overstocked, eradication of aquatic plants is al-
most certain, and, as a result, increases in nutrient concentrations, blue-
green algal blooms, turbidity, and also changes in fish communities. The
long-term consequences of aquatic plant eradication are poorly under-
stood, however.
The introduction of grass carp into hydrologically open systems (reser-
voirs, manmade ponds) has raised important questions about escape and
reproduction in habitats where vegetation is desirable. While environmental
requirements for successful reproduction are stringent and were once
believed to be an adequate barrier to their multiplication in North American
waters, grass carp have apparently reproduced in the United States. More
recently, sterile triploid grass carp have been developed and are the only
type of grass carp permitted in many States. While their reproduction is not
possible, their escape in large numbers from a hydrologically open system,
such as a reservoir, can still pose a significant threat to a downstream
habitat where aquatic vegetation is desired. :
INSECTS: Significant negative environmental impacts of insects have not
been observed, except for changes in aquatic habitats associated with
macrophyte elimination.
143
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& COSTS. Cost comparisons for biological controls-are generally not yet'
available, but these methods do appear to be far less costly than the traditional
alternatives of chemical or mechanical treatments. These latter techniques, in
addition to the costs of equipment, materials, labor, and insurance, must be
reapplied frequently.
Shireman (1982) and Shireman et al. (1985) report that $117,232 had been
spent on endothal for the temporary control of hydrilla in Lake Baldwin, Florida.
The hydrilla problem was eliminated with grass carp at a cost of $8,499 ($43
per acre). Unlike herbicide or harvesting treatments, the grass carp exert con-
trol for many years with one treatment, so that costs are amortized. By way of
comparison, harvesting costs in Florida can easily be $1,000 per acre, while
chemical costs in Florida range from approximately $200 to 400 per acre
(Cooke and Kennedy, 1989). Harvesting and herbicide costs in northern
climates are essentially the same. Also, Shireman (1982) points out that, in
1977, the cost of chemical treatment of 37,000 acres of hydrilla in Florida was
$9.1 million; the cost of grass carp to provide long-term control would have
been about $1.71 million if stocked at a density of 14 fish of 8 inches or longer
per acre. Table 6-5 compares the costs of using harvesting, herbicides, and
grass carp to manage aquatic weeds.
Table 6-5.—Cost comparisons, in 1984 dollars, of three symptomatic
treatments for nuisance aquatic weeds (Florida data for grass
carp). ' : :
PROCEDURE COST RANGE
Harvesting
Midwest
Florida
Herbicides
• • Midwest
Florida'
$1 40-31 0 per acre
$31 0-5,200 per acre
$210-415 per acre
$210-415 per acre
Grass Carp* $90 per acre"
(cost is also amortized due to
long-term- effectiveness
'12 inch or greater Irsh. stocked at 14-20 per acre.
Macrophytes—Techniques with
Shorter-Terrn Effectiveness
Harvesting
• PRINCIPLE. Harvesting is a procedure to cut and remove nuisance rooted
plants and associated filamentous algae. Unlike Herbicide applications where
plants are left in the lake .to die, decompose, and release nutrients and organic
matter, harvesters may have some restorative value in lakes with dense infes-
tations and low external loading because plants and the associated organic
matter and nutrients are removed. Some potable water supply systems use
them to reduce the concentration of organic molecules in raw water, which,
144
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when chlorinated in the treatment plant, produce potentially carcinogenic
molecules such as trihalomethanes. Harvesters can clear an area of vegeta-
tion without the post-treatment waiting period associated with herbicides and
without significant danger to nontarget species.
• MODE OF ACTION. The typical harvester is a highly maneuverable, low-
draft barge designed with one horizontal and two vertical cutter bars, a con-
veyor to remove cut plants to a hold on the machine, and another conveyor to
rapidly unload plants (Fig. 6-8). Some manufacturers sell shore conveyor units
to assist loading from harvester to truck and high-speed barges to carry cut
plants from the harvester to shore. Harvesters vary in size and storage
capacity from about 200 ft3 (6 m3) of cut vegetation to 800 ft3 (23 m3). Cutting
rates range from about 0.2 to 0.6 acres per hour, depending on machine size.
The barge itself can be very useful with other lake improvement procedures,
including alum applications.
Weed disposal is usually not a problem, in part because lakeshore resi-
dents 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.
Primary power source
2 cylinder deutz diesel
, Operator console
Cutting bed rams
Vertical sicHp bar
cutters
Figure 6-8.—The Aquamarine Corporation's H650 harvester. (Courtesy of Aquamarine Cor-
poration.)
• EFFECTIVENESS. Most harvesting operations are successful in producing
at least temporary relief from nuisance plants and in removing organic matter
and nutrients without the addition of a potentially deleterious substance. Plant
regrowth can be very rapid (days or weeks), especially in southern waters
where midsummer growth rates of water hyacinth can exceed the rate at which
they can be harvested. Several case histories illustrate the effectiveness of
harvesting in northern waters. .
A bay of LaDue Reservoir (Geauga County, Ohio) was harvested in July
1982 by the traditional method in which the operator treats the weed bed like a
residential lawn and simply mows the area. Stumps of Eurasian watermilfoil
•plants about 0.5 to 3 inches in height were.left, and complete regrowth oc-
curred in 21 days. In contrast, the slower method of lowering the cutter blade
about "1 inch jnto the soft lake mud will produce season-long control of milfoil
by tearing out roots (Conyers and Cooke, 1983). Of course this cutting tech-
nique is of little value where sediments are very stiff or in deeper water where
145
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the fength of the cutter bar (usually 5 to 6 feet) cannot reach the mud. When
only plant tops are cut, regrowth may be rapid. There is evidence of a carry-
over effect (less growth in the subsequent year), especially if an area has had
multiple harvests in one season. ', . ,
Some weed species are more sensitive to harvesting than others. Nichol-
son (1981) has suggested that harvesting was responsible for spreading milfoil
in Chautauqua Lake, New York, because the harvester spreads fragments of
plants from which new growths can begin. On the other hand, he considers
pondweeds to be far more susceptible because these species emphasize
sexual reproduction and regenerate poorly from fragments. Harvesting there-
fore could mean that milfoil could replace the pondweeds.
There are few data on the .actual restorative effects of harvesting, in the
sense of removing significant amounts of nutrients or in reducing the release of
nutrients and organic matter to the water column. If nutrient income is
•moderate and weed density high, as much as 40 to 60 percent of net annual
phosphorus loading could be removed with intense harvesting. This would be a
significant nutrient removal in many cases. Milfoil may be a large contributor of
phosphorus to the water column throughout the summer, which strongly sug-
gests that removing this plant through harvesting could curb this source of
nutrients to algae. An herbicide application would leave the plants to decom-
pose and release nutrients and organic material to the water column. On the
other hand, harvesting itself can increase water column phosphorus con-
centration either through mechanical disturbance of sediments or by enhanc-
ing conditions for phosphorus release from sediments.
Effective use of a harvester.to manage aquatic plants and to minimize
regrowth during the 'season includes the purchase of a machine of sufficient.
size to handle the affected areas, the use of proper cutting techniques, and the
siting of disposal areas near the areas to be harvested. .
• POTENTIAL NEGATIVE IMPACTS. The following are-some of the possible
negative effects of harvesting:
1. Cutting and removing vegetation can be energy- and labor-intensive
and therefore expensive.
2. Only relatively small areas can .be treated per unit time, which may
create lake user dissatisfaction."
3. A high capital outlay for equipment is required.
4. Plants may fragment and spread the infestation.
5. Small fish may be removed.
6. Operating depths are limited.
7. Favorable weather is required.
8. Machine breakdown can be frequent, especially if an undersized piece
of equipment is purchased.
• COSTS. Harvesting costs in the Midwest have ranged from $140 to $310
per acre when costs from extreme situations are omitted (Table 6-5), making
the technique somewhat less expensive than herbicide treatments; costs in
146
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Florida have routinely exceeded $1,000/per acre. Expenditures of a particular
project will be for machine cost, labor, fuel, insurance, disposal charges, and
the amount of downtime: Estimates of manpower time and costs can be ob-
tained from the HARVEST model developed by the U.S. Army Corps of En-
gineers (Hutto and Sabol, 1986), which runs on a personal computer. The
program is available from the program manager of the Aquatic Plant Control
Research Program at the U.S. Army Engineers Waterways Experiment Sta-
tion, P.O. Box 631, Vicksburg, MS 39181-0631.
Herbicides
• PRINCIPLE AND MODE OF ACTION. Poispning nuisance aquatic weeds
is perhaps the oldest method used to attempt their management. Few alterna-
tives to herbicides existed until recently. The pesticide industry has grown and
has been more carefully regulated so that some of the most dangerous and
toxic herbicides, such as sodium arsenite, have be,en replaced with chemicals
that have much lower toxicity to nontarget biota and leave degradable
residues.
• An herbicide treatment can be an effective short-term management proce-
dure to produce a rapid reduction in vegetation for periods of weeks to months.
Pesticide use cannot be equated with lake restoration, since causes of the
weed problem are not addressed nor are nutrients or organic matter removed.
Plants are left to die and decompose. New plants will shortly regrow, some-
times to densities greater than before.
The use of herbicides remains controversial and emotion-charged, in part
because they have been promoted as, and confused with, restoration proce-
dures, and in part because their positive .and negative features have been
poorly understood by both proponents and opponents. For example, as
pointed out by Shireman et al. (1982), herbicide treatments are presently the
only means-of opening the vast acreage of water infested with the exotic water
hyacinth (Eichhorniae crassipes) in Florida and other southeastern States.
This is a case in which chemicals for management are a necessity until some
other more long-term control, such as plant-eating insects, can be established.
Their broad-scale use in other climates, often for the purpose of seasonal
eradication of weeds, is more controversial, especially since equally cost-ef-
fective alternatives have smaller environmental impacts.
Many opponents of herbicides fear their effects on fish and fish-food or-
ganisms. Some chemicals can be toxic at high doses, but most have low
toxicity to aquatic organisms. The impacts of herbicides on humans is poorly.
understood, and there is almost no information on the long-term ecological
consequences of their use. ,
Lake managers who choose herbicidal chemicals need to exercise all
proper precautions. As shown in Table 6-6, some chemicals are specific to cer-
tain species and therefore the nuisance plants must be carefully identified.
Users should follow the herbicide label directions exactly, use only an her-
bicide registered by EPA for aquatic use, wear protective gear during applica-
tion, and be certain to protect desirable plants. Most States require applicators
to be licensed and to have adequate insurance. Among the important factors to
be considered before adopting a management program with herbicides'are the
• following questions: .
1. What is the acreage and volume of the area(s) to be treated? Proper -
dosage is based upon these facts.
147
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Table 6-6.—Common aquatic weed species and their responses to herbicides
(adapted from Nichols, 1986).
EMERGENT SPECIES
Altemantherca philoxeroides
(alligatorweed)
Dianthera americana
(water willow)
Glyceria borealis
(mannagrass)
Phragmites spp (reed)
Sagittaria sp (arrowhead)
Scirpus spp (bulrush)
Typha spp (cattail)
FLOATING SPECIES
Brasenia schreberi
(watershield)
Eichhornia crassipes "
(water hyacinth) •
Lemna minor (duckweed)
Nelumbo lutea
(American lotus)
Nuphar spp (cowlily)
Nymphaea spp (water lily)
SUBMPRGED SPECIES
Ceratophyllum demersum
(coontail) -
Chara supp (stonewort)
Elodea spp (elodea)
Hydrilla verticHlata
(hydrilla)
Myriophyllum spicatum
(milfoil)
A/a/as flexilis (naiad)
A/a/as guadalupensis
(southern naiad)
Potamogeton amplifolius
(large-leaf pondweed)
P. crispus
(curly-leaf pondweed)
P. djversifolius
(waterthread)
P. natans
(floating leaf pondweed)
P. pectinatus
(sago pondweed)
P. illinoiensis
(Illinois pondweed)
Ranunculus s'pp
(buttercup)
YES - Controlled
BLANK - Information unavailable
DIQUAT
YES
NO
NO
YES
NO
YES1
YES
NO
NO
NO
YES
NO2
YES
YES
YES ,
YES
YES
?
YES
NO
YES
YES
•
YES
ENDOTHAL
•
NO
'NO •
NO
NO
YES
NO
NO
YES
YES
YES
NO2
?
YES
YES-
YES
YES
YES
YES
YES
YES
YES
2,4-D
YES
YES
NO
YES
YES
YES
YES '.
YES
YES
'YES
YES
YES
YES
NO2
NO,
YES
NO
NO
NO
NO
NO
YES
NO
YES
GLYPHOSATE
(RODEO)
YES'
YES
YES
. YES
NO
YES
' YES
:
NO?
NO
NO
FLURIDONE
(SONAR)
,YES
- YES
YES
YES
NO
NO
YES
YES
/ YES
. YES
YES
YES
• YES
• YES
YES
YES
YES
YES
NO • Not Controlled • . '
9 Questionable, Control
1 plus chel'ated copper sulfate 2 controlled by copper sulfate ..
Source: Anonymous. 1979: Arnold. 1979: McCowen el al. 1979: Nichols. 1986: Pennwalt Corp.. 1984: Schmitz. 1986:
and Getsmger. 1988
Westerdahl
148
2. What plant species are to be controlled? This will determine the
herbicide and dose to be used.
3. What will the long-term costs of this decision be? Herbicides must be
, reapplied annually, or in some cases, two to three times per season.
-------
4. How is this waterbody used? Many herbicides .have restrictions (days)
on water use, following application.
5. Is the applicator licensed and insured, and has a permit been obtained
from the appropriate regulatory agency?
There are several useful and well-written reference manuals to facilitate
plant identification and the determination of the proper chemical and its dose.
These include Aquatic Weeds, 1979, Fisheries Bulletin No. 4, Department of
Conservation, Springfield, IL 62706; and especially the Aquatic Plant Iden-
tification and Herbicide Use Guide by Westerdahl and Getsinger (1988).
• EFFECTIVENESS. Table 6-6 lists some aquatic weeds and the herbicides
known to control them. The following paragraphs briefly describe each com-
monly used herbicide.
• Diquat. The effectiveness of diquat is inactivated in turbid water because
of its sorption to particles! it does not persist in the water but can remain
toxic in lake sediments for months. Many users combine it with copper
sulfate, producing a potent, broad-scale herbicide-algicide. The reader
is cautioned to note the toxic features of copper, described in an earlier
section.
• Endothall. Endothall is sold in several formulations: liquid (Aquathol. K),
granular dipotassium salt (Aquathol), and the di (N, N-dimethyl-
alkylanine) salt (Hydrothal) in liquid and granular forms. Effectiveness
can range from weeks to months. The potassium salt forms have been
shown to persist in the water for 2 to 46 days.
• .2,4-D. 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 18 to 36
pounds per acre are usual for submersed weeds, most often of the
dimethylamine salt or the butoxyethanolester (BEE). This herbicide is
particularly effective against Eurasian watermilfoil (granular BEE applied
to roots early in the season) and, in a foliage spray against water
• hyacinth. 2,4-D has a short persistence in the water but can be detected
in the mud for months.
• Glyphosate. This herbicide is effective against floating leaves and emer-
gent aquatic plants but not against submersed species.
• Fluridone. Fluridone is sold in liquid and pellet formulations as an her-
bicide for emersed and submersed weeds. It is a persistent compound
and will not exert effect until 7 to 10 days after application. Control may
be evident for an entire season, and sediments may remain toxic to
plants for more than a year.
Label registration restrictions on water use following treatment are very im-
portant and should -be followed carefully regardless of the herbicide chosen.
Each State has its own regulations, as well.
• POTENTIAL NEGATIVE IMPACTS. Many, but not all, nontarget aquatic or-
ganisms appear to have high tolerances to the herbicides just discussed. Di-
quat is a notable exception because of its toxicity to some Crustacea, a staple
of fish diets.
149
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The primary environmental, impacts include release of nutrients to the water
column and consumption of dissolved oxygen during plant decomposition.
Algal blooms, dissolved oxygen depletions, and nutrient release from sedi-
ments can fojlbw a treatment. Another significant problem is that a species un-
affected by the herbicide may replace the target species. Stonewort and
pondweeds often invade a treated area. When a target weed is replaced by an
algal bloom or a resistant weed, another chemical may have to be used,
making herbicide treatment even more expensive.
Shireman et al. (1982) caution that the following lake or pond charac-
teristics almost invariably produce undesirable water quality changes after
treatment with an herbicide for weed control:
1. High water temperature
2. High plant biomass to be controlled
' 3. Shallow, nutrient-rich water
4. High percentage of the lake's area to be treated,
5. Closed or nonflowing habitat.
Competent applicators will be cautious in treating a lake with these conditions.
There has been a long-standing debate over the effects of 2,4-D on
humans. Men exposed to 2,4-D and/or 2,4,5-Tfor more than 20 days per year
may face an increased risk of non-Hodgkins' lymphoma (Hoar et al. 1986).
• COSTS. Herbicide treatments are expensive for what they accomplish.
They produce no restorative benefit, show no carryover of effectiveness to the
following season, and may require several applications per year. The short-
term benefit-cost ratio can be desirably high, but the long-term benefit-cost
ratio is likely to be very low.
The ranges of per-acre costs for harvesting and herbicide; treatments are
similar in northern climates, but grass carp treatments cost significantly less
than either (Table 6-5). It should be recalled, however, that harvesters remove
nutrients and organic matter—a potential source of trihalomethane (THM)
precursors and of dissolved-oxygen consumption—that can have a carryover
effect to subsequent seasons.
One study of harvesting and herbicide (Diquat and copper sulfate) costs
showed that harvesting was more expensive only in the initial year when the
machinery was purchased. In the following years, maintenance, operation, in-
surance, and weed disposal costs were lower than those for chemicals alone.
Harvesting, in this case history, cost $115 per acre and herbicides $266 per
acre, so that over a five-year period, not including herbicide price inflation or
applicator fees, the use of chemicals would have been 2.6 times more expen-
sive than harvesting and without the benefits of nutrient and organic matter.
removal (Conyersand Cooke, 1983).
Shireman (1982) has compared the costs of chemical and biological (grass
carp) control of hydrilla in Florida. A chemical treatment of 3*,000 acres in
1977 cost $9.1,.million, whereas a grass carp introduction would have cost
$1.71 million. Of course the grass carp exert control slowly while herbicides
provide prompt, though short-term relief.
150
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Regional cost ranges can be expected for herbicides (see Table 6-5). Varia-.
tions in costs are brought about by size of area to be treated, density of the in-
festation, species, and problems unique to a particular lake.
Macrophytes—Summary of
Restoration and Management
Techniques
Table 6-7 is a summary of the procedures described in this section. Qualitative
evaluations about short- and long-term effectiveness, costs, and potential for
negative side effects are presented. These judgments are the consensus of 12
lake and reservoir restoration experts.
Table 6-7.—Comparison of lake restoration and management techniques for
control of nuisance aquatic weeds.
TREATMENT
ONE APPLICATION
Sediment Removal
Drawdown
Sediment Covers
Grass Carp
Insects
Harvesting
Herbicides
SHORT-TERM
EFFECT
'E' •
G
E
P,
'P
E
E .
LONG-TERM
EFFECT
E'
F
F
. E
G
.'F :
P
CHANCE OF
COST NEGATIVE EFFECTS
P
• .:E
- P
E
' E . ..
F '
:. F
F
; F
. . L
F ;
' L
F
H
E, Excellent F = Fair G • Good P Poor H ;• High
Problem IV: Eutrophic Drinking
Water Reservoirs
Nature of the Problem
Those who drink water from surface water supply reservoirs often detect un-
pleasant tastes, odors, and color. They may be unaware of more serious
problems that are unknown to the user but are of concern to potable water
treatment plant managers and State and Federal EPA officials: the presence of
potentially toxic materials in treated water. Toxic material can enter drinking
water supplies directty by runoff from the land (for example, herbicides). They
can also be created in the treatment process when treatment plant chemicals
interact with naturally occurring organic molecules in the raw water to form
potentially dangerous compounds such as trihalomethanes (THMs).
151
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Many of the problems in potable water treatment are caused by eutrophic
conditions in the water supply reservoir. Poof taste and odor are associated
with algal blooms. Some of these algae, the blue-greens, produce toxins lethal
to domestic animals and may be linked to certain summer illnesses in
humans.
Colored drinking water js usually caused by a high concentration of iron and
manganese in the raw water. This occurs when the raw water intake is deep
and withdraws oxygen-free hypolimnetic water. THMs are a class of organic
molecules—chloroform is in this class—that are produced through an interac-
tion between the disinfectant (chlorine) added to raw water to kill microbes and
certain organic molecules in the raw water. The organic molecules come from
the watershed, primarily in the form of plant decay products, and from weeds
and algae in the reservoir. The concentrations of these organic molecules are
expected to be higher in more eutrophic waterbodies. THMs are believed to be
carcinogenic. The U.S. EPA has set an upper average amount (0.1 ppm) past
which finished water should not go.
Other eutrdphication-related problems in water supply systems include a
gradual loss of water storage as silt deposits increase, rapidly escalating costs
connected with increased chemical use to clean the raw water, and such in-
plant problems as clogged filters.
Water Supply Reservoir Management
The traditional approach to improving drinking water quality is to upgrade the
in-plant treatments. Sometimes, this is effective, particularly where the water
supply is in good to excellent condition. In other cases, however, a costly in-
crease in chemical use is required or additional equipment may have to be in-
stalled. Treatments with granulated active carbon, which may be needed to
remove pesticides and other organics from the raw water, might cost a modest-
sized city millions of dollars in initial capital costs plus the high costs of opera-
tion.
The better the incoming raw water, the less it will cost to make it into ac-
ceptable drinking water. Ultimately, watershed and reservoir protection and
reservoir management or restoration may be less costly than extensive in-plant
modifications and increased chemical uses. As already pointed,out, however,
reservoirs are very difficult to protect because their drainage basins, which are
•often large relative to reservoir area, usually include several political and
economic units and may have extensive and uncontrollable human uses. The
city or controlling authority may have to embark on a long-term effort to buy
land, encourage or subsidize wastewater treatment plant upgrades, improve
municipal storm water discharges, and help land users employ modern agricul-
tural practices.
One alternative or an addition to drainage basin management is the use of
chemicals (such as alum) in the river to strip phosphorus from the water before
it enters the reservoir. This can involve a prereservoir detention basin or the
addition of a chemical to the stream.
Another option is to divert river water into a smaller, square-sided, weedless
basin where silt deposition and additions of flocculent could occur. Wahnbach
Reservoir, an example of this, was described in Chapter 4. The basin can be
periodically drained and dredged. .
Water supply reservoirs near highways, railroads, and within industrial
areas are vulnerable to accidental spills of toxic materials. Few reservoirs are
protected or prepared for this. The silt basin described above, built large
152
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enough to hold a three- to five-day supply, could also serve as an emergency
raw water supply. .
Theoretically, most of the techniques described earlier in this chapter could
be used to improve water Duality, or to actually restore the reservoir after poor
quality waters are diverted. In practice, however, restoration techniques a.re
not easily applied to reservoirs because of their size and the difficulty of reduc-
ing loadings. The following paragraphs list drinking water quality problems and
.possible in-reservoir solutions.
Color
Iron and manganese, appear in oxygen-free raw water. Three solutions are
common: artificial circulation, hypolimnetic aeration, or elevating the intake
from the hypolimnion to the epilimnion. Drawing water from the epilimnion can'
introduce taste and odor, and the aerator could destratify a shallow reservoir,
triggering an algal bloom. ,
Taste and Odor
Algal blooms, particularly blue-green algae, not only can impart an unaccep-
table taste and odor but can also increase the demand for treatment chemicals
and decrease filter runs. There are few solutions if nutrient diversion is not
adequate. Artificial circulation could reduce productivity of planktonic algae in
deep reservoirs but is unlikely to be effective in shallow ones. Sediment
removal and especially phosphorus inactivation,—both procedures to curtail
sediment nutrient release—will be eventually overwhelmed by high loading but
offer the possibility of improvement for several years. Copper sulfate, an al-
gicide, can be used for short-term relief, but applications are often followed by
more severe blooms and release of substances that add to THM production.
Loss of Storage Capacity
This problem can be solved only by removing silt and curtailing its income. A
stringent permitting process may be imposed by the U.S. Army Corps of En-
gineers if dredging is chosen because the reservoir is a potable water supply.
Trihalomethane Production
A search for sources of organic THM precursor molecules in the drainage
basin must be undertaken, followed by appropriate land management to curtail
their generation, Marshes are known to be important sources. A substantial
fraction of the organics can come from sediments, weeds, and algae, which
strongly suggests that in-reservoir management of these sources could
produce a significant decrease in THM production. Harvesting would be an ef-
fective procedure. Another possibility is to add. clean well water to dilute the
raw water at the intake. A book on reservoir management for-water quality and
THM precursor control is available (Cooke and Carlson, 1989).
153
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Problem V: Fish Management
Nature of the Problem
Most lakes and reservoirs are used to some extent for fishing, and some (ac-
cording to fishermen) are considered unsatisfactory. Problems with fishing
usually fall into the following categories:
1. Conflicts between users—including high fishing pressure
2. Interference with fishing by weeds
3. Overabundance and population imbalances—especially of "stunted"
. fish or undesirable species .
4. Poor reproduction and die-off of desirable species
5. Low lake fertility and fish production.
User conflicts are not trivial. Chapter 9 addresses the problem of regulating
these conflicts.
Fish production is directly related to lake or reservoir fertility. This fact is
also the source of many fishery problems. In nutrient-rich waters, such as
those often encountered in the lakes and reservoirs of the North or Midwest
ecoregions or in situations of heavy wastewater or agricultural inflows, high fish
biomass is likely to be found. But high fertility may also promote intense algal
blooms, encourage heavy fishing pressure that can limit other lake uses such
as waterskiing, and ultimately give rise to lakes and reservoirs with serious im-
balances in fish species and to the complaint that the lake is "fished out."
In other ecoregions, such a& some of those in the West and Southwest,
lake and reservoir fertility may be so low that there is little fish production, so
stocking efforts fail, and the lake must be fertilized. Lake Mead, Nevada-
Arizona, is a case in point (Axler et al. 1988). Thus, both low and high fertility
situations are likely to require fish management and lake or reservoir manipula-
tions.
Improvement of a lake or reservoir for fishing requires both lake and fish
management. Bennett (1970), citing Leopold (1933), defines fish management
as "the art and science of producing sustained crops of wild fish for recreation-
al and commercial uses." Competent programs include a diagnostic study of
the lake or reservoir and its fish community and then implementation of
management options that are ecologically sound and within financial con-
straints.
Diagnosis and Management
Just as with lake restoration, a diagnosis of the condition of the fish community
is the first step in a fish management program. For most situations, this invol-'
ves fish sampling to provide an assessment of the condition of the lake's
present fish community. Various sampling methodologies, and strategies are
available, the specific • approach being dependent upon the region in the
country where the lake is located, the type of fish to be sampled, the purpose
of the sampling, and the characteristics of the particular lake. Before attempt-
154
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*
ing to diagnose a fishery condition, consultation with State or local fisheries
professionals is strongly recommended. ' •
Additional studies, will usually be required, including determinations of'
temperature and dissolved oxygen profiles and many of the other factors re-
lated to diagnosing and solving problems related to eutrophication, or its ab-
sence, as described in Chapters 3 and 4. Management may then proceed at
several levels, including the physical-chemical level (e.g., hypolimnetic aera-
tion, whole lake fertilization), the habitat level (e.g., installation of artificial
reefs, aquatic plant control), and biological level (e.g., fish removal or stock-
ing). Bag or siot length limits can be imposed so that management also invol-
ves the fishing population as well. A good description of some of these pos-
, sibilities is found in the summary of a NALMS Workshop (McComas et al.
1986). Their implementation should involve the advice of knowledgeable
professionals, including State agency personnel. .
Fisheries management, as described earjier, is often an integral part of a
lake restoration plan. It is important to remember that lake ecosystems are
complex and highly interconnected. Fishermen may urge a lake manager to
stock predators, such as walleye, muskie, or bass to improve fishing .or ever) a
lake's water quality. However, corrective stocking can fail. Often the lake is at
or near its productive capacity. Game fish fry stocked in a poor quality lake
may not survive the many sources of mortality, including intense predation.
The stocking of significant numbers of older fish is expensive and the animals
are more difficult to obtain. High fishing pressure can quickly reduce their num-
bers once stocked. Similarly, some lake managers have heeded advice to
stock forage species, s.uch as shad, only to discover later that shad reproduc-
tion exceeded predation by top predators or shad grazing on zooplankton was
sufficient to relax grazing pressure on algae. The problem of poor fishing might
then have been traded for nuisance quantities of forage fish or excessive.
growths of algae.
There are several valuable sources of information about fish management.
Each State has a fisheries unit that can provide important guidelines specific to
that geographic area.
Problem VI: Acidic Lakes
Acidic waters are detrimental to many aquatic organisms; High concentrations
of hydrogen and aluminum ions in acidic waters adversely affect ion regulation
in aquatic organisms (a condition known as osmoregulatory failure). The prin-
cipal detrimental effect on fish and other organisms is the leaching of sodium
chloride from bodily fluids. The general types of changes in fish species ex-
pected to occur with increasing surface water acidity at 0.5 pH intervals are
summarized in Table 6.8. Loss of important sport fish species generally occur
at pH levels below 6.
Acidic lakes occur in areas where the soils have no natural buffer capacity
and where acid rain and other manmade or natural processes cause acidifica-
tion of waterbodies. Many of these lakes are unable to support a healthy,
reproducing fishery. Some waters are mildly acidic because of their.passage
through naturally acidic soils. Acidic drainage from abandoned mines affects
thousands of miles of streams and numerous lakes throughout Appalachia and
in .other coal and metal mining areas.
155
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Table 6-8.—General effects on fish species anticipated with surface water
acidification, expressed as a change in pR (source: J. Baker et al.
1990). ; • • ,
pH DECREASE ' GENERAL BIOLOGICAL EFFECTS
6.5 to 6.0 .Some adverse effects (decreased reproductive success) may occur
for highly acid-sensitive fish (e.g., fathead minnow, striped bass)
6.0 to 5.5 Loss of sensitive species of minnows and dace, such as blacknose
dace and fathead minnow; in some waters,decreased reproductive
success of lake trout and walleye, which are important sport fish
species in some areas
5.5 to 5.0 Loss of several important sport fish species, including lake trout,
walleye, rainbow trout, and sm'allmouth bass, as well as additional
nongame species such as creek chub
5.0 to 4.5 Loss of most fish species, including most important spprt fish species
such as brook trout and Atlantic salmon; few fish species able to
' survive and reproduce below pH 4.5 (e.g., central mudminnow, yellow
perch, and, in some waters, largemouth bass)
Lakes can be effectively restored and managed to support desired fisheries
by addition of neutralizing materials or by other related techniques. The follow-
ing sections describe five techniques that have been used to restore acidic
lakes. Most techniques rely on addition of limestone materials to upland
streams, the lake surface, or the lake watershed. Two other techniques, injec-
tion of base materials, into lake sediments and pumping of alkaline
groundwater into lakes, are also described. There is very little experience with
the latter two neutralization methods. The five methods and some others are
described in more detail by Olem (1990). tif±
Limestone Addition to Lake Surface
• PRINCIPLE. Limestone, a naturally occurring mineral product, is often the '
major component of surface water, buffering systems; it is a basic material that
neutralizes acidity when applied to waterbodies. Limestone works in the same
way that common antacid tablets neutralize excess stomach acids. The active
ingredient in most antacids is calcium carbonate, the same compound in Ijme-
stone. Because it is used extensively for agricultural liming, limestone is easily
available at a low cost. . .
• MODE OF ACTION. When added to surface water, limestone dissolves
slowly, resulting in a gradual increase in pH. It is often desirable to add enough
limestone so that some settles to the bottom of the lake. This "sediment" dose
results in continued slow dissolution over time. Limed waterbodies typically in-
crease in pH to levels between pH 7 and 9. These pH levels are best for growth
and reproduction of some aquatic organisms. When limestone is added to
acidic surface waters, dissolved aluminum concentrations are lowered be-
cause aluminum is less soluble in neutral waters. Also, the toxic forms of
aluminum— Al+3 and AI(OH)2— are no longer dominant at pH levels above 6.
Lake water dissolved aluminum is thus reduced to nontoxic levels for fish and ;
other aquatic organisms.
The most common method of adding-alkaline materials is spreading a slurry
of limestone and water to the lake surface by boat. Helicopters are often used
to lime lakes that may be inaccessible by boat.
156
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• EFFECTIVENESS. Application of limestone over the lake surface has been
shown.to be effective for lakes with water retention times over about six
months. The, effects typically last about twice the lake retention time. For in-
stance, a lake with a-retention time of 6 years will normally maintain neutral
conditions for up to 10 years after liming. Other techniques are recommended
for lakes with very short retention times because the effects of direct lake
liming are too short-lived. The direct liming method has been the most widely
.applied technique to mitigate acidic conditions in lakes. It has been widely
adopted to neutralize acidic lakes in Scandinavian countries. For example,
about 5,000 lakes have been treated with limestone in Sweden since 1977.
• POTENTIAL NEGATIVE IMPACTS. There have been few instances where
liming has caused mortalities in resident fish populations. A few, isolated inci-
dents of fish mortality have occurred because of metal toxicity. These cases
have often been due to improper treatment and stocking of fish after liming.
Also, treatment of lakes high in metal concentrations may result in fish mor-
tality. For example, during the liming of a lake near a Canadian metal smelter,
metal hydroxides were observed to precipitate onto fish gills.
Injection of Base Materials into Lake
Sediment
This is an experimental procedure that has been applied to only a few lakes
(Lindmark, 1982, 1985). The technique consists of injecting neutralizing
materials such as limestone, hydrated lime, or sodium carbonate into the sedi-
ments of acidic lakes. Calcium or sodium ions in the sediment are released in
exchange for hydrogen ions in the water column. This results in a gradual
change in lakewater pH and an increase in acid neutralizing capacity to the
water column during spring and fall lake turnover. The technique has also been
shown to release phosphorus from the sediments to the water column, result-
ing in increased productivity and subsequent benefits to the fish. The techni-
que is generally, limited to small, shallow lakes with soft organic sediments and
adequate road access for transport of materials and application equipment. In
laboratory experiments, this treatment was shown by Ripl (1980) to last about
five to seven times longer than adding limestone to the lake surface. The tech-
nique has the potential to disrupt the benthic community and increase water
column turbidity, and it may cost more than liming lake water.
Mechanical Stream Doser
It is possible to neutralize acidic lake water by continuously adding limestone
to upland streams using mechanical dosing equipment. Several types of
stream dosing devices exist. The more common dosers are automated devices
that release dry powder or slurried limestone directly into streams. The dis-
tribution of limestone from dosers powered by electricity or by battery is con-
trolled, automatically by microprocessors programmed to calculate appropriate
dosing rates from remotely monitored water quality or jiydrological parameters.
Dosers powered by water flow distribute neutralizing material at rates that vary
with the flow.
157
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Few streams have been treated using these devices because they have not
been well developed and there are several inherent difficulties in treating flow-
ing systems. For instance, it is difficult to accommodate rapidly changing flow
conditions and ensure proper operation of mechanical equipment, particularly
during storms and.freezing temperatures. The treatment is continuous, expen-
sive, and is not generally recommended unless all other alternatives are ruled
out.
Limestone Addition to Watershed
The addition of limestone to portions of the-lake watershed, also known as soil
or watershed liming, is considered an experimental procedure in the United
States.'A viable "alternative to the direct addition of base materials to surface
waters, its principal advantage is that the effects of this type of treatment are
more sustained. The slower response of lakes to watershed liming also
reduces the likelihood of rapid changes in acid-base chemistry and its effects
on metal solubility and fish toxicity. ,
Soils are used here in a broad sense to mean areas other than the lake or
stream water surface and include dry soils and wetland areas.
Experience with watershed liming has indicated that it is very important to
apply the limestone to major water pathways. This practice avoids treatment of
the entire, watershed and reduces the amount of limestone required.
Although watershed liming has been relatively uncommon, it has'increased
in recent years. For example, about 2 percent of the total limestone used in
liming treatments in Sweden was applied to soils in 1983; by 1987,15 percent
was used.in this practice (Nyberg and Thornelof, 1988).
'Watershed liming may be particularly applicable to lakes with short reten-
tion times (less than six months) because its effects are much longer lasting
than direct lake liming. Also, watershed liming can reduce the severity of
episodic acidic conditions and the leaching of toxic aluminum from the soils to
the lake water. . .
Although the cost of one application is higher than direct lake liming, the
overall costs may be similar or lower because of the more sustained effects.
Rossetand and Hindar (1988) calculated that the watershed liming of Lake
Tjonnstrond, Norway, in 1983 would last 30 years compared to less than one
year for direct lake liming.
Pumping of Alkaline Groundwater
Pumping of water from a nearby source that contains alkalinity has been sug-
gested as a viable technique for neutralizing acidic surface waters., It is pos-
sible to pump deep groundwater to an acidic lake because these sources often
contain more alkalinity than nearby surface waters. This method has been
tested in Pennsylvania and Wisconsin. In Pennsylvania, groundwater was suc-
cessfully pumped from wells to neutralize an acidic section of Linn Run to help
the stream sustains put-and-take trout fishery. The Wisconsin experiments
have not been reported. •
An important consideration is the possible depletion of groundwater reser-
ves by continuous pumping. It is not known whether the method has wide ap-
plications or whether the costs of treatment compare favorably to other mitiga-
, tion methods for acidic surface waters.
158
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Acidic Lakes—Summary of Restoration
and Management Techniques
Table 6-9 summarizes the procedures described in the preceding sections for
mitigation of acidic conditions in lakes. A qualitative comparison. of the
methods is presented with regard to short- and long-term effectiveness, costs,
potentiat negative impacts, and relative use.
Table 6-9.—Comparison of lake restoration and management techniques for
neutralization of acidic lakes.
TREATMENT (ONE APPLICATION)
Limestone addition to lake
surface
Injection of base materials
into lake sediment
Mechanical stream doser
Limestone addition to
watershed
Pumping of alkaline
groundwater
E Excellent G Good F Fair
SHORT-TERM
EFFECT
E
E
'E
G
E
P Poor
LONG-TERM
EFFECT COST
F G
G F ,
E P
E G
? ?
NEGATIVE
EFFECTS
E
G
G;
G
G
RELATIVE
USE
E
P
P
G
P
159
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Chapter 7
HYPOTHETICAL CASE
STUDY
Purpose of Case Study
Armed with all the explanations, guidance, instructions, and information in the
preceding chapters, could a lake user or lake association group "do lake manage-
ment?" The answer is yes. These associations are the driving force behind the
many lake restoration and management programs in the United States. They may
hire experts, but the burden of making the critical decisions and bearing the
responsibility for organizing and sustaining a restoration program is typically
borne at the grass roots level. The hypothetical case study in this .chapter il-
lustrates how a lake management or restoration program can be carried out. This
- case study integrates the information and .material from the previous sections, in-
cluding problem definition, in-lake restoration techniques, watershed manage^
ment, data analysis, and the evaluation and selection of management alterna-
tives.
Lynn Lake—a hypothetical waterbody—suffers from excessive algae, aquatic
weeds, :and siltation. Ljke most lakes that are managed and restored to good con-
dition by involved citizens, Lynn Lake is extremely popular locally. It is not one of
the largest or most important lakes in the State, or even well known outside the
State, Restoration will take major effort and a considerable dedication of local
citizens^but it can be done. The rest of the case study will demonstrate how res-
toration is accomplished.
Lynn Lake—A Case Study
Lynn Lake is located completely in Kent County. There is a county park on the
western side of the lake, but the entire perimeter is accessible to the public. The
lake is used heavily for fishing, swimming, and boating; well-used jogging and
walking trails circle it. Swimming is often prohibited because of high le'vels of
algae and bacteria. Boating is impaired by macrophytes that cover 50 percent of
the lake. Siltation of the inlet areas of the lake has also limited the use of these
161
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area$ for boating. Lynn Lake (Fig. 7-1) has two major tributaries: Kimmel Creek
. and Tag Run. The city of Middletown is located on Kimmel Creek and has a
secondary wastewater treatment plant that discharges to the creek. Upstream of
Middletown is Blue Ridge, a 200-unit subdivision that is presently under construc-
tion. Tag Run, the other tributary, is surrounded mostly by wetlands, ponds, and
undeveloped land.
•o
a>
I
I
M
•a
o
&
i
8
a
I
&
3
1
O)
E
162
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Problem Definition
Because of concern over the declining condition of the lake, the .county collected
several water samples and analyzed them for nutrients (phosphorus and
nitrogen) and algae. The results indicated that the lake has high levels of phos-
phorus and nuisance blue-green algae. County officials decided to conduct a sur-
vey (Table 7-1) over Fourth of July weekend to ask residents who used the lake
what problems they had observed and to gage the degree of concern and poten-
tial support for restoring the lake to better condition. Interest in.the lake proved
high because 70 percent of the households in the Lynn Lake basin responded to
the questionnaire. Results of this informal survey, summarized in Table 7-2, indi-
cated that the public participated in all recreational aspects of the lake, with walk-
ing, picnicking, fishing, and boating being the dominant uses. Results also
showed that 98 percent of those who answered the questionnaire supported a
lake restoration project if partially funded by State or Federal grants, and 74 per-
cent supported the program if funded solely by the county. .
Table 7-1.—Public opinion questionnaire.
1. How often do you visit Lynn Lake? :—: • _. • :—;
2. How far do you travel to visit Lynn Lake? _—I :—. : —
3. When you visit Lynn Lake, what activities do you participate in?
E Picnicking " ' D Jogging C Swimming
L7 Walking.- . . D Boating p Other : .
D Fishing
4. Since Lynn Lake appears to be suffering from excessive algae, aquatic weeds;
and siltation, do you support a lake restoration program that would include,a study
of the lake and the implementation of a program to eliminate the lake problems?
P Yes p No P Undecided , . • _. ' . . :
5. Restoration of Lynn Lake will require the expenditure of county funds. Partial
funding of the restoration program may be obtained from a State or Federal grant.
'Realizing this, do you still support the implementation of a lake restoration program
for Lynn Lake?
P Yes, only if State or Federal funds are available to offset the cost of the ;•
program. ' '
p Yes; even if only county funds are used. ,
ti No D Undecided .. : ' '.
.It should be noted at this point, that while Lynn Lake meets all of the criteria for
an EPA Clean Lakes grant, including the fact that it is a publicly owned waterbody
with several recreational water uses available to everyone, many lakes do not
meet these criteria. Furthermore, many problem lakes dp not require the infusion
of Federal funds to accomplish an effective lake, protection and restoration pro-
gram. The approach to the diagnosis and development of a management plan
provided here, moreover, isjnore comprehensive but generally applicable to most
lake situations, including private lakes and others for which Clean Lakes Program
funds are not available. However, the approach can be modified, depending on
existing information and resources, for-effective lake restoration.
Based on the results of the survey, the county held a special meeting in
August to discuss a restoration program for Lynn Lake. County staff presented
the results of the questionnaire and outlined a proposed study of the lake. During
the discussion period, the citizens repeated their support for the proposed res-
toration project. Many users believed that the lake's problems were caused by
discharges from.,the Middletown treatment plant, erosion and runoff from new
construction (especially the Blue Ridge Development), erosion from farmland,
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Tabte 7-2.—Public opinion questionnaire results.
1. How often do you visit Lynn Lake?.
TIME . PERCENT
Daily 3
Weekly 32
Monthly 56
Annually , 9
2. How far do you travel to visit Lynn Lake? —'. -.
MILES PERCENT
0-2 29
2-5 33
5-10 36
>10 2
3. When you visit Lyhn Lake, what activities do you participate in?
78 Picnicking 32 Jogging , _2 Swimming
59 Walking 61. Boating Other Model Boats: 1
101 Fishing . ' Necking: 1
4. Since Lynn Lake appears to be suffering from excessive algae, aqatic weeds, and
siltation, do you support a lake restoration program that would include a study of
the lake and the implementation of a program to eliminate the lake problems?
100% Yes 0% No 0% Undecided
5. Restoration of Lynn Lake will require the expenditure of county funds. Partial
funding of the restoration program may be obtained from a State or Federal grant.
Realizing this, do you still support the implementation of a lake restoration program
for Lynn Lake?
98 Yes, only if State or Federal funds are available to offset the cost of the
program. .
74 Yes, even if only county funds are used. • .
2 No 0 Undecided
and nutrients leaching from -failing septic systems. They also suggested that
erosion from roadway construction and maintenance being performed by the ,
State Highway Department was contributing, to the sedimentation problem.
Several lake users indicated that a few. areas of the shoreline were sloughing or
caving in. Green algal scums and weeds, however, were universally agreed to be
the major problem.
At the end of-the meeting, the county formally formed a special committee to
investigate the possibility of restoring Lynn Lake. The committee was made up of
the County Engineer, the Director of the County Planning Department, the Direc-
tor of Middletown Public Works, and four interested lake users. The County Com-
missioners also approved a motion to hire a consultant if help could not be found
through the county staff or State office first. It was agreed that the special commit-
tee would seek out recommendations of firms capable of helping with the restora-
tion project, review qualifications, and recommend a consultant.
In the next month, members of the special committee sought information and
sources of help in lake restoration. They asked the State Water Control Board,
the State Game and Fish Commission, and the State Health Department whether
any programs existed ,that could be used to study or restore Lynn Lake. Since no
State program or funding dedicated to lake preservation or management existed,
the' committee asked for general information on lake restoration and ,as much
guidance as possible. A staff member of the State Water Control Board collected
names of lake associations arid municipalities in the State that were involved in
lake restoration, and the committee contacted these groups to find out how they
had carried out their projects and who they might recommend as a consultant.
One member of the special committee, who was also a member of the North
American Lake Management Society, suggested that they call the NALMS office
in Washington, D.C. The committee ordered a booklet on lake restoration and ex-
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plained the types of problems Lynn Lake was having. The NALMS .office sent a
list of consultants in Lynn Lake's area who specialized in lake restoration and a
list of NALMS members who had agreed to help lake associations and
municipalities with general questions such as how to find help and how. to estab-
lish a public information program to support the work. •
The committee contacted lake associations and municipalities in the State that
had begun restoration projects and asked them who they had used to carry out
the work, how they had paid for it, what the consultant had done for them, how
much the program had cost, whether it had been effective, and whether they were
satisfied with the results.
At the next meeting, the special committee reported its findings. The commit-
tee voted to initiate a lake restoration program that would include the following ac-(
tivities:
1. Forming a lake restoration advisory committee;
2. Selecting a consultant to perform the lake study, evaluate the
management alternatives, assist in implementing the restoration program,
and help the association find funding to support the work and prepare any
grant application packages;
3. Developing a detailed work plan;
4. Submitting a grant application to the EPA for a Phase I
Diagnostic/Feasibility Study;,
5. Performing a study of Lynn Lake that would quantify the problems and
problem sources and result in the development of a comprehensive lake
and watershed management program;
6. Submitting a grant application to EPA for a Phase II Lake Restoration
Program if Lynn Lake qualified for a Phase I grant; and
7. Implementing the restoration program.
Lake Restoration Advisory
Committee
The first step in the restoration program was to form an advisory committee repre-
senting various interests in the watershed that would be responsible for providing
direction throughout the program. It was recognized that for the project to be suc-
cessful all interests in the watershed would need to represented and their con-
cerns and desires addressed. A committee was formed that consisted of repre-
sentatives from the following municipalities, agencies, and groups:
Q Friends of Lynn Lake—a fund-raising
organization
Q Lynn Lake Fishing Club
Q Kent County
Q The Kent County Homebuilders Association
a Kent County Soil and Water Conservation
District :
O U.S. Soil Conservation Service
Q Middletown Sewer Authority
Q State Water Control Board
Q State Health Department
Q State Highway Department
Q East Kent Garden Club
O State Game and Fish Commission
: Q Farm Bureau
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Responsibilities of the Lake Restoration Advisory Committee included:
* ' • i
• Reviewing consultant qualifications and recommending a consultant to
the County Commissioners; .
• Providing direction throughout the project by frequently meeting with
the corisultant;
• Reviewing the consultant's work including data analysis, conclusions,
and recommendations;
• Obtaining public input to the proposed management alternatives;
• Approving the final lake and watershed management plan prepared by
the consultant;
• Recommending the acceptance and implementation of the
management plan to the County Commissioners; and
• Assisting in the implementation of the lake and watershed
management plan.
Consultant Selection
Since no one involved in the project was experienced in lake studies and restora-
tion, the county decided to retain a consultant to assist in developing a iake res-
toration program. Realizing that it would be applying for Federal funds from the
"EPA's Clean Lakes Program, the county followed the Federal procurement
guidelines provided in 40 CFR Part 33—"Minimum Standards for Procurement
Under EPA Grants." It recognized that the procurement guidelines would be use-
ful whether or not Federal funds were available. The county then decided to use
the negotiation method of procurement. The Advisory Committee mailed requests
for qualifications to eight firms, reviewed the qualifications, and interviewed three
that were asked to indicate specific experience in several of the lake manage-
ment areas, as listed in Table 3-3 of Chapter 3.
The Advisory Committee selected a consultant who demonstrated the neces- •
sary qualifications and experience, which included the successful completion of
projects involving algae and weed problems similar to those experienced at Lynn
Lake. The consultant was selected to provide the following services:
1. Develop a detailed work plan that would meet all requirements of an EPA
Phase I Diagnostic/Feasibility Study;
2. Develop a Phase I grant application; • . - ,
3. Perform a diagnostic study, with or without Clean Lakes funding;
4. Assist in the selection of a cost-effective restoration program;
/ .
5. Develop a grant application for the Phase II Lake Restoration Program if
Lynn Lake appears to be eligible for such funding or develop'a
fund-raising program if Lynn Lake were not eligible;
6. Design in-lake and watershed management practices; and
7. Implement the restoration program.
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By including all of these tasks in the consultant selection process, the Advisory
Committee ensured that one consultant would be involved from start to finish and
that further consultant selection procedures would not be required.
Detailed Work Plan
The consultant developed a work plan that included'the following activities:
1. Study of lake and watershed characteristics
2. Study of lake and watershed aesthetics and recreational characteristics
3. Limited lake monitoring
4. Limited watershed monitoring
5. Data analysis ,
6. Development and evaluation of management alternatives
7. Selection of a watershed management and lake restoration program
8. Projection of benefits
9. Environmental evaluation
10. Presentation to the homeowners association
11. Progress reports and final report
In developing the detailed work plan, the consultant reviewed the limited exist-
ing water quality data on Lynn Lake and evaluated the natural characteristics of
the lake and watershed. The consultant also met several times with the Advisory
Committee to discuss project goals, potential problem areas in the watershed
(such as Middletown treatment plant, erosion from agriculture, construction and
roadway maintenance, and septic system leachate), and the availability of local
resources (in-kind services) that could be used during the study.
In-kind services from local sources and State offices may be counted as part
of the State's contribution for Clean Lake Program funding. See Chapter 8 for
suggestions regarding Federal agencies that may support lake restoration or
watershed management (nonpoint source control) programs.
To keep the diagnostic study costs to a minimum, the consultant decided that
the following local resources could be used as in-kind services:
1. KENT COUNTY
• Provide boat for lake monitoring
0 Provide land use data for study
9 Assist in the installation of watershed monitoring stations
9 -Assist in the evaluation and selection of management alternatives
" Assist in public participation activities
0 Review and comment on final report
9 Attend project meetings
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2. SQIL CONSERVATION SERVICE
• Identify agricultural problem areas .
• Assist in the identification and evaluation of agricultural control
measures, attend project meetings
• Provide cost information
• Provide technical information
• Advise on funding through other U.S. Department of Agriculture
programs
3. MIDDLETOWN SEWER AUTHORITY
• Provide wastewater treatment plant effluent data
• Analyze lake and stream samples in treatment plant laboratory
4. STATE WATER CONTROL BOARD
• Review progress reports and final report . •
• Attend project review meetings
5. STATE GAME AND FISH COMMISSION
\
• Conduct a fish population survey .
• Review progress reports and final report
• Attend project review meetings
The final work plan included a detailed description of study tasks, project
responsibilities, the project budget (cash and in-kind services), and the project
schedule. Costs for in-kind services were calculated using an hourly cost rate '
based on salary plus overhead.
Phase I Grant Application
The county decided to apply for EPA Clean Lakes financing because the Lynn
Lake project appeared to be an ideal candidate. .It not only met the criteria for
public access but was also the most heavily used public lake within a three-hour
commuting radius. Furthermore, the lake's deterioration was pronounced; without
restoration, the lake was likely to become unusable for several recreational pur-
suits within a few years. The enthusiastic public support for restoration was also
in the lake's favor. Clean Lakes funding provides a matching form of grant (that is,
70 percent Federal, 30 percent State funds); both the county and the general
public were willing to support the cost of a restoration project through in-kind ser-
vices and direct contributions. Many lake restoration projects, however, are con-
ducted using only local funds and volunteer help and services.
The consultant developed a Phase I grant application that consisted of the
completed EPA application forms along with the detailed work plan. Although the
consultant developed the grant application for the county, the official applicant
was the State Water Control Board since EPA regulations allow Clean Lakes Pro-
gram grants to be given only to State agencies. The State Water Control Board,
168
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therefore, reviewed the grant application and submitted it along with their priority
ranking of the project. -
After both the EPA regional and headquarters offices had reviewed and
evaluated the application, EPA approved the application and offered the State a
Phase I grant. The State then subcontracted with Kent County to perform the
Phase I study. Kent County in turn contracted with the consultant to perform the
technical tasks of the Phase I study. -
Lake and Watershed Study
Study of Lake and Watershed
Characteristics
The study of Jake and watershed characteristics was performed primarily by col-
lecting'and analyzing secondary data—data already available from other sources
including the State Water Control Board's 208 Water Quality Management Plans,
U.S. Geological Survey maps, aerial photographs, and State and local publica-
tions. Using these sources, the consultant obtained the following information:
1. Physical lake characteristics (area, depth, mean flow)
2. Some general chemical and biological characteristics of the lake
(temperature, dissolved oxygen, nutrients, algal population, fish
population)
3. Watershed characteristics (drainage area, land use, topography, geology,
and soils) and
4. Possible pollutant sources (wastewater treatment plant discharge,
construction sites, agricultural areas, and failing septic systems).
Insufficient existing data were available to clearly define the lake's mean
depth, its volume, or its chemical and biological condition. The work plan was
designed to fill in these and other gaps in information. Also, although the consul-
tant, working with the input from the Advisory Committee, was able to identify
potential pollutant sources, not enough information was available to quantify and
rank them.
The products of this task were some basic information about the lake and a
set of watershed maps illustrating land use, topography, geology, soils, and pos-
. sible pollutant sources.
Study of Previous Uses and
Recreational Characteristics
Using existing reports and information, the consultant identified the following in-
formation on the lake and watershed:
1. Historical uses (walking, joggingLboating, swimming, fishing, and
picnicking)
2. Past lake problems (excessive algae, aquatic weeds, poor fishing
success, and siltation leading to loss of recreational uses) '
3. Public access locations
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The product of this task was basic information on lake uses and users, infor-
mation useful for clarifying project goals and developing a management program.
Much of this information may already be available for local projects and not re-
quire much time. Compiling this information is required for a Clean Lakes grant.
Lake Monitoring
Because of the lake's shape, three sampling stations were located on it, as
shown in Figure 7-2. One station was located over the deepest part of the lake
while the other two stations were located in the two arms of the lake to adequately
characterize water quality. Samples were collected monthly from September
through April and biweekly from May through August. Besides meeting EPA
monitoring requirements, the sampling program was designed to obtain more
samples during the warm weather period (May through August) when the biologi-
cal activity and chemical changes are at their maximum.
Figure 7-2.—Lynn Lake monitoring stations.
170
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Three depths were sampled at each station because the lake stratified. Water
samples were collected at half a meter below the surface, half a meter above the
bottom, .and near middepth. The mid-depth station was located within the
metalimnion, the water stratum where temperature and dissolved oxygen change
the most.
Each water sample was analyzed in the laboratory for the following chemical
parameters:
Total Phosphorus Total Suspended Solids ,
Soluble Reactive Phosphorus Alkalinity
Organic Nitrogen . Iron
Ammonia Nitrogen Manganese -
Nitrate Nitrogen
Field measurements at each sampling station included a temperature and dis-
solved .oxygen profile with measurements taken at intervals of 1 meter (using a
combined temperature-dissolved oxygen meter). Field measurements also in-
cluded pH, conductivity, and Secchi depth. The Seechi depth measures the
transparency of the water.
•Water samples collected from the half-meter depth were also analyzed for
chlorophyll a, phytoplankton, and zooplankton. Chlorophyll a measures the algal
biornass in the surface waters of the lake. The phytoplankton (floating algae) and
zooplankton (floating microscopic animals) analyses consisted of identifying and
counting the various algae and microscopic animals in the samples.
The State Game and Fish Commission's District Fish Biologist conducted a
creel census in the spring. To determine the type of fish being caught, the physi-
cal condition of the fish, and the catch per unit effort or how long it takes to catch
a fish.
A macrophyte (aquatic weed) survey was performed in August and consisted
of identifying the type and distribution of aquatic plants in the lake. Since siltation
of the lake is a problem, bathymetric (bottom contour) and sediment depth sur-
veys of the lake were performed to determine the water and sediment depth of
the entire lake. The surveys consisted of measuring the water depth with a depth
recorder and the depth of the unconsolidated (loose) bottom sediments by prob-
ing with a steel rod at cross sections throughout the lake. A survey crew was used
to pinpoint the location of the cross sections.
At each of the three lake stations, a sediment sample was collected and
analyzed for the following parameters:
SEDIMENT SAMPLE PARAMETERS
Total Phosphorus Iron
Total Nitrogen .. Manganese
Percent Solids EP Toxicity Test '
Percent Organic Solids
The products of this task were physical, chemical, and biological data on the
lake water and sediments. These data would be analyzed later to determine the
present ecological condition of the lake. Another product of this task was
bathymetric data that would be used to calculate the volume of the lake and to
determine whether dredging was a feasible management alternative. This infor-
mation is critical in any lake restoration project to formulate a cost-effective plan.
171
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Watershed Monitoring
As discussed in Chapter 4, the first step in analyzing and modeling a lake is to es-
tablish a water balance and budget of materials (for example, nutrients, sediment,
organic matter). Chapter 4 also indicated that a water balance and materials
budget could be obtained either indirectly by comparing the watershed to a
similar watershed or directly by monitoring the streamflow and pollutant loads
over a one-year period. The direct measurement method is obviously more ac-
curate and reliable than the indirect estimate method, but it also requires more
resources. Since sufficient funds and resources were available, the direct mea-
surement method was used to calculate an annual water balance and pollutant
budget. •
To calculate an annual sediment and nutrient budget for Lynn Lake, the con-
sultant (with assistance from Kent County) installed stream monitoring stations on
Kimmel Creek, Tag Run, and the lake's outlet, as shown in Figure 7-3. Each
stream station consisted of an automatic water level recorder and sampler. Volun:
teers serviced the.stations as part of in-kind services. The consultant measured
cross-sectional area and velocity of the stream during selected rain events, data
that was used to develop a stream rating curve correlating stream water level with
streamflow. This information was used in conjunction with the water level read-
ings to calculate streamflows throughout the study period. A staff gage was also
installed in the lake to monitor changes in lake level and thus water storage (or
loss) to or from the lake.
Figure 7-3.—Location of stream monitoring stations.
172
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In some lakes, groundwater income can be a very important source of water
and, sometimes, of nutrients. Because Lynn Lake had a very high income of
water via.the two streams, it was believed that groundwater was an insignificant
component of the overall water budget. In reservoirs, this may often be the case.
In many natural lakes, stream inflow is small and groundwater may be very impor-
tant. In these cases, wells could be placed around the lake and groundwater in-
flow determined if sufficient funds were available. At the same time, nutrient con-
centration in groundwater would also be determined. However, if insufficient
funds had not been available, groundwater contributions for both water and
nutrients could have been estimated by assuming any water and nutrient con-
tributions not.accounted for in the water; nutrient budgets are attributable to
groundwater.
An automatic water sampler (Fig. 7-4) was electrically connected to the water
.level recorders and programmed to cpllect water samples when the stream level
Increased during rain events. These are water level changes that occur very
rapidly, often (it seems) during the night or on holidays when volunteers cannot
be present to note them. During each rain event, discrete water samples were
collected at half-hour intervals over the stream hydrograph as shown in Figure 7-
5. (Depending on the size of the stream and land use in the watershed, the sam-
pling time interval can be adjusted from 15 minutes to several hours.) After each
storrin event, selected water samples were taken to characterize sediment and
nutrient loading at various times during the storm. One or more samples were
taken as the flow increased, near the peak discharge, and as the flow decreased.
Figure 7-4.—Automated stream monitoring station used to collect flow and water quality data.
173
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1
H—
E
co
co
Storm Hydrograph
Low flow
Time
Figure 7-5.—Typical stream hydrograph showing increase in stream water level during a rain
event and showing how an automatic sampler collects water samplers at solect time intervals.
Each selected sample was analyzed for the following parameters:.
Total Phosphorus
Soluble Reactive Phosphorus
Total Nitrogen
Ammonia Nitrogen
Nitrate Nitrogen
Total Suspended Solids
These selected samples permitted the development of a nutrient to sediment
concentrations versus flow relationship that was used to estimate loads during
nonsampled storms, based on the flow records.
A total of nine storm event? were monitored, which provided sediment and
nutrient loading data representative of nonpoint source pollution such as water-
shed erosion and runoff. Dry weather stream monitoring was also performed to
obtain baseflow stream loading data. Dry weather stream monitoring consisted of
collecting grab samples from the two tributaries and the lake's outlet once each
month during the study. Each sample was analyzed for the same variables as the
wet weather samples.
The products of this task were flow and. water quality data for both dry and wet
weather conditions for the two tributaries and the lake's outlet as well as changes
in water storage in the lake. Precipitation directly on the lake and water loss
through evaporation were estimated from data obtained at a nearby National
Oceanic and Aeronautic Administration weather station.
Data Analysis
Lake Analysis
The lake's mean and maximum depths and volume were calculated for the
bathymetric survey data. The hydraulic residence timer-the theoretical time re-
quired to displace the lake volume as explained in Chapter 2—was calculated
using the lake volume and the mean annual discharge from the lake. The limiting
174
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nutrient was suggested by, the nitrogen to phosphorus ratio in the lake during the
study period. If the total nitrogen to total phosphorus ratio is greater than 10 to 1,
phosphorus is usually the limiting nutrient. Throughout most of the study, the
nitrogen to phosphorus ratio was generally greater than 17 to 1 indicating that
phosphorus was generally the limiting nutrient and that the in-lake and watershed
management program should be concentrated on reducing phosphorus loads
entering and within Lynn Lake.
Figure 7-6 illustrates some summer temperature and dissolved oxygen
profiles for Lake Station 1. Temperature stratification began in late May and be-
came progressively more pronounced over the summer, in most cases, a shallow
lake with as large a surface area as Lynn Lake's would destratify frequently from
summer storms. Lynn Lake, hpwever, is sheltered from prevailing winds by high
bluffs and trees so that it remains stratified all summer. Cool weather in Septem-
ber, however, allowed enough heat loss from the lake to make destratification
possible. •
o
10
20
30
May 13
June 16
July 14
July 28
Temp. 0 10 20 30 0
D.O. 0 5 10
August 11 .
10
20 300 10 20 30-0
10
20 30
15 0 5 10
August 25
150 5 10 15 0 , 5 10 15
September 10 September 23
.
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solved oxygen to bottom waters when the lake mixed in the fall changed chemical
conditions there, and more phosphorus was precipitated to the sediments than
was released. -.'.-"
Chlorophyll a and phytoplankton levels, varied during the study. However, the
mean summer chlorophyll a concentration was 18 ppb, which is indicative of
eutrophic conditions. During the summer and early fall, the phytoplankton was
dominated by nuisance blue-green algae. Except for periods after rain events, the
Secchi depth decreased with increased phytoplankton levels. A comparison of
Lynn Lake data to EPA eutrophication criteria is presented in Table 7-3. This com-
parison indicated that Lynn Lake is eutrophic. A summary of Lynn Lake charac-
teristics, based on study results, is presented in Table 7-4.
Table 7-3.—Comparison of Lynn Lake data to eutrophic classification criteria
(EPA,1980) ,
PARAMETER
LYNN LAKE
EUTROPHIC CRITERIA CONCENTRATION
Total Phosphorus (ppb as P)
(winter)
Chlorophyll a (ppb)
(summer)
Secchi Depth (m)
greater than 25
greater than 10
less than 2.0
50.0
18.0
1.1
Table 7-4.—Characteristics of Lynn Lake
Lake Area (acres)
Watershed Area (acres)
Watershed to Lake Area Ratio
Mean Depth (feet)
Maximum Depth (feet)
Volume (acre-ft)
Outflow (acre-ft/yr)
Mean Hydraulic Residence Time (years)
Tropic Condition
Limiting Nutrient
.. 500
. 4400
9:1.
20
45
10000
4501
2.2
.. Eutrophic
Phosphorus
Another indication of Lynn Lake's eutrophic condition was found in Carlson's
index.. This index, as Chapters 3 and 4 explain, can be a valuable tool for quan-
tifying lake trophic status from basic, readily attainable data. Indices calculated
from Lynn Lake range from 58 to 61, indicative of eutrophic conditions (see Fig. 7-
7).
Evaluation of the lake data indicated that Lynn Lake was suffering from the fol-
lowing problems:
• Excessive algal growth ,
• Excessive weed growth in the inlet area
• Excessive siltatibn in the inlet area
• Phosphorus release from the lake sediments.
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OLIGOTROPHIC MESOTROPHIC EUTROPHIC .HYPEREUTROPHIC
20 25 30 35 40 45
LI I I
ii mma
TOTAL II
PHOSPHORUS (PPB) n
• AVERAGE MEASUREMENTS
UNDER CURRENT CONDITIONS
Figure 7-7.—Carlson's Trophic State Index for Lynn Lake, indicating that Lynn Lake is
eutrophic. •
Watershed Analysis
The lake and stream data were used to calculate an annual water balance and
nutrient budget, using the techniques discussed in Chapter 4. In addition to the
stream and outlet monitoring, data were also collected for the Middletown treat-'
ment plant and for the quantity and quality of rainfall in the watershed. The annual
water balance was calculated using the equations provided in Chapter 4.
Stream and lake data collected over a one-year period consisted of water
quality data for 12 monthly dry-weather samples and 9 composite storm samples.
The annual stream phosphorus load to Lynn Lake was calculated by adding both
the dry weather and wet weather loads. The dry weather or baseflow load was
calculated using the 12 monthly phosphorus concentrations and the continuous
streamflow data.
Since the nine monitored storms only represented a portion of the total storms
that occurred during the monitoring period, a statistical relationship between the
total phosphorus concentrations and flow was used with other storm flows to cal-
culate the annual wet weather phosphorus load. The phosphorus load for the
area draining directly into Lynn Lake was extrapolated using the stream load
data.
The annual point source load from the Middletown treatment plant was calcu-
lated from daily flow records and biweekly chemical data. The annual direct rain-
fall phosphorus load was calculated from rainfall quantity and quality data col-
lected during the study.
Table 7-5 lists the annual water balance and phosphorus budget for Lynn
Lake. This table follows the format provided in Table 4-1 of Chapter 4. It provides
a complete accounting of drainage areas, flows, and loading. Similar tables were
developed for nitrogen and sediment budgets.
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Table 7-5.—Annual water balance and external phosphorus loading for Lynn Lake
ITEM
Kimmel Creek
Tag Run
UngaugedArea
WWTP
Atmosphere
Total
Evaporation
Outflow
AREA
ACRES
300
3500
100
500
4400
500
4400
%PF TOTAL P
FLOW TOTAL LOADING
AC-FT/YR INFLOW LBS/YR
375
3885
111
80
1250
5701
1200
4501
6.6%
, 68.1%
1.9%
• 1 .4%
21.9%
100.0% .
v, 21-0%
79.0%
Net Phosphorus Retention
180
315
9
655
89
1248
612
636
%PF
TOTAL
LOADING
14.4%
25.2%
0.7%
52.5%
7.1%
100.0%
0.0%
49.0%
51.0%
RUNOFF
IT/YR
1.25
1.11
.1.11
2.50
1.30
2.40
1.02
TOTAL P
EXPORT
LB/AC-YR
0.600
0.090 '
0.090
0.178
0.284
phosphorus loading model predictions for Lynn Lake:
T » mean hydraulic residence time (years)
• Lake volume (ac-ft).' mean outflow (ac-ft/yr)
- 10.000 nc-ft / 4.501 ac-ft/yr
= 2.22 years
PI - average inflow p concentration (ppb)
- total p loading (Ibs/yr) x 368 ' lake outflow (ac-ft/yr)
» 1,248 Ibs/yr x 368 / 4,501 ac-ft/yr
- 102 ppb
P " predicted lake phosphorus concentration (ppb)
- PI / (1 + VT)
- 102 / (1 + V2.22) - 41 ppb
observed lake phosphorus concentration = 50 ppb
Application of the phosphorus loading model described in Chapter 4 (Table 4-
2) to Lynn Lake yielded a predicted lake phosphorus concentration of 41 ppb, as
compared with the average measured concentration of 50 ppb. The higher
measured value suggested the presence of an additional external or internal
phosphorus source that iib not considered in Table.7-5. The consultant concluded
that, based upon geologic factors and lake water balance information, significant
groundwater contributions were unlikely. Review of lake monitoring data indicated
that soluble phosphorus was-released from bottom sediment during periods when
the bottom waters were devoid of oxygen. Severe algal blooms often followed
periods of high winds, which caused mixing of phosphorus-rich bottom waters
"into the surface layer. Based upon these considerations, it was concluded that
lake bottom sediments were likely to be important internal sources of phosphorus
that should be addressed in a restoration program.
Since the external loads listed in Table 7-5 do not indicate specific land uses
or activities that produced these loads, the consultant performed field investiga-
tions throughout the watershed to identify specific nonpoint source problem areas
that indicated that Tag Run is in good condition. The Soil Conservation Service
provided specific .information on problem agricultural areas in the watershed, and
active construction sites were surveyed to estimate the magnitude of soil erosion
oc?urring during rain events. Based on the external phosphorus budget and an
evaluation of the field investigation, the consultant concluded that the fol.lowing
phosphorus sources were significant and should be controlled:
• Middletown wastewater treatment plant
• Agricultural activities (Tag Run), ,
• Construction activities (Kimmel Creek). '
Evaluation of Management Alternatives
Management alternatives for Lynn Lake were divided into watershed manage-
ment and in-lake management alternatives. The first priority was to determine
whether watershed management practices were needed to reduce the pollutants
178
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entering the lake. After all, the best in-lake management program will not succeed
if there still is an excessive inflow of nutrients, silt, and organic matter. Therefore,.
it is important to determine whether the annual pollutant load to the lake is exces-
sive. For Lynn Lake, the significance of annual phosphorus loading to the lake
was estimated by using the Vollenweider Phosphorus Loading Diagram shown in
Figure 7-8, and explained in Chapter 4. This curve, which relates the average in-
flow phosphorus concentration to the ratio of mean depth to hydraulic residence
time, indicates that the annual phosphorus loading to Lynn Lake is probably ex-
cessive and should be controlled.
Future projections for Lynn Lake shown in Figures 7-7 and 7-8 assume im-
plementation of the recommended management strategies, to be described.'Ad-
vanced treatment of the Middletown wastewater discharge would reduce annual
external phosphorus loading by 491 pounds per year. The consultant estimated
that implementation of the recommended watershed management practices
would reduce the phosphorus loading from Kimmel Creek by approximately 25
percent, or 45 pounds per year. Overall, the external phosphorus loading would
be reduced by 43 percent from 1,248 to 741 pounds per year. Figures 7-7 and 7-8
indicate that this reduction would restore Lynn Lake to a mesotrophic status.
Average water transparency would increase from 1.1 to 2.7 meters and average
chlorophyll a concentrations would decrease from 16 to 5 ppb. The selection of
specific alternatives to achieve these results is described in the next section.
1000
CO
O.
Q.
6
O
o
w
II
! 5'
I
100
10
| LYNN LAKE[ . ^, •
CURRENT CONDITIONS
P=60
__ —-POST^RESTORATION
P=25 , __ __ — —• -
P=10
HYPER-EUTROPHIC
EUTROPHIO,
MESOTROPHIC
OLIGOTROPHIC
PREDICTED LAKE PHOSPHORUS (PPB)
JL
J_
.01 -1 1 10 100
HYDRAULIC RESIDENCE TIME (YEARS)
LAKE VOLUME/OUTFLOW
Figure 7-8.—Vollenweider phosphorus loading curve for Lynn Lake Indicating that Lynn Lake
Is eutrophlc and receiving excessive phosphorus loading.
179
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Evaluation Criteria
The following criteria were used.in the evaluation of lake and watershed manage-
ment alternatives:
• Effectiveness , '
• Longevity . •
• Confidence
l _
• Applicability
• Potential negative impacts
• Capital costs • • -
• Operating and maintenance costs.
Effectiveness
Effectiveness relates to how well a specific management practice meets its goal.
, For instance, dredging would be considered effective jf it met the identified goals
of increasing the lake's depth and capacity, removing excessive nutrients from
the lake, and eliminating Weed problems. A management practice may be partially
effective in that goals may be incompletely met. For instance, dredging may in-
crease the depth and capacity, but excessive nutrients may still exist in the
remaining sediments, or algae may continue to be a problem in some areas of the
lake. . ;
For some management practices, such as dredging, initial determinations of
effectiveness can be based on the specific design and extent of the practice. If all
the loose sediments are removed from the lake, all goals will be met. However, if
funds are limited and only partial dredging is carried out, only partial effectiveness
will be obtained. The decision, therefore, becomes a trade-off between effective-
ness and other factors such as costs, available funds, negative impacts, and
public acceptability.
FoY other management. practices such as alum treatment or sedimentation
basins, effectiveness is not straightforward and cannot be completely defined
prior to implementation. Alum treatment, for example, depends upon many factors
that could influence its effectiveness. If, following alum addition, high sediment or
nutrient loads continue to enter the lake, the beneficial effects of alum treatment
would be negated. Similarly, a detention basin is designed to treat a specific
streamflow. If rain events occur that 'produce a streamflow in excess of the design
flow, the effectiveness of the basin will be reduced. Effectiveness of management
practices, therefore, must be evaluated based on the past experience of the ef-
fectiveness of the practice, the commitment to implement part or all of the re-
quired practice, and an analysis of the risks and variabilities involved.
Longevity
Longevity reflects the duration of treatment effectiveness. Treatments are usually
categorized as short term or long term. A treatment or management practice is
defined as short term if it is effective for one year or less. Weed harvesting, for ex-
ample, is usually a short-term technique that is immediately effective but may
only last for a period of several weeks or a single growing season. The short-term
longevity of a treatment or management practice, however, is not inherent in the
process; it usually varies with specific environmental conditions. Three copper
180
-------
suffafe treatments might control algal blooms on one lake for an entire growing
season, while on another lake, weekly treatments would be necessary to over-
come the effects of a high flushing rate and incomes of new nutrient-laden water.
Treatment or management practices that produce short-term effects will result in
long-term effectiveness if they are reapplied each year. For example, a farmer
may use conservation tillage each year to produce a1 long-term benefit from the
method.
A treatment or management practice is usually defined as long term if it is ef-
fective for more than a year. The long-term effectiveness, like short-term effec-
tiveness, depends on both environmental conditions and the specific, manage-
ment practice. A sedimentation basin will provide long-term treatment
effectiveness if it is properly designed for specific environmental conditions, such
as streamflow fluctuations and pollutant loadings, and if it is properly maintained.
If, however, the basin was designed too small, it.will not continue to remove pol-
lutants effectively. If the accumulated sediments are not periodically removed, the
long-term effectiveness will be decreased by poor maintenance: Dredging will
provide long-term effectiveness if the dredging program was properly designed
and-if watershed management practices have already been implemented. If ex-
cessive siltation still occurs, the long-term effectiveness of dredging will be
decreased. Construction of grass waterways on farmland will provide long-term
effectiveness if properly designed and if maintained each year.
•
Confidence
Confidence refers to the number and quality of reports and studies supporting the
effectiveness rating of a treatment. Some in-lake procedures such as dredging
have been extensively applied and studied. Confidence in the effectiveness of
dredging is'high, based on its record of successful application. Other techniques
such as lake aeration have not been studied as extensively, and their confidence
evaluation is therefore lower. In addition, poor confidence can arise from a vari-
able record. It is not currently understood, for example, why aeration works well in
some lakes and does hot in others.
Applicability
Treatment applicability refers to whether or not the treatment directly affects the
cause of the problem and whether it is suitable for the region in which it is con-
sidered for application. For example, nutrient concentrations in runoff from mid-
western agricultural fields are often high and promote noxious algal blooms, The
perceived problem is algal blooms, but the cause is excessive nutrients. Nutrient
inactivation with alum can temporarily reduce nutrient levels in the lake water but
cannot address the true origin of the problem—upstream agricultural watersheds.
Nutrient inactivation, therefore, is not applicable to the prpblern of incoming
nutrients; it can be applicable, however, to the, problem of nutrient release from
sediments into the water column. Flushing may be highly applicable where water
is plentiful, but not in a region where water is scarce. .
Potential Negative Impacts
Lakes are dynamic ecosystems; changing one element of the lake ecosystem
may cause a beneficial or adverse change in another element. In developing a
lake management program, the lake manager should take a holistic view of the
ecosystem to ensure that a proposed management practice does not cause a
negative impact on the lake ecosystem. For example, control of algae may bring
gibout an expansion of the submersed macrophyte problem. On the other hand,
181
-------
the excessive removal of macrophytes may affect fishing by eliminating spawning
and nu'rsery areas,, which would result in a decline in fish production. Obviously,
some practices have short-term negative impacts that cannot be eliminated.
Dredging usually destroys the bottom-dwelling organisms, but new organisms
can recolonize within a year.
Capital Costs
Standard approaches should be used to evaluate the cost effectiveness of
various alternatives, In evaluating costs of alternative methods, the lake manager
must balance the other factors already described; namely, effectiveness, lon-
gevity, confidence, applicability, and potential negative impacts. It is rare that the
benefits of different management practices are equal. Furthermore, limited funds
and resources often force the lake manager to select the most affordable rather
than the most cost-effective alternative. Many municipalities arid lake associa-
tions elect to treat their lake's weed problem annually with a herbicide rather than
dredge their lakes because they do not have sufficient funds for dredging.
Assuming, however, that the benefits of alternative management practices are
equal or nearly equal, the annual cost method should most likely be used to
determine thejnost cost-effective alternative. In this method, all costs must be
calculated usfng the same discount rate, and the annual cost must be based on
the same period of analysis.
An example of the annual cost method is provided for comparing dredging
arid alum treatment of Lynn Lake. The targets of dredging and alum treatment are
almost the same—to reduce phosphorus in the lake. .
Cost Comparison: Alum Treatment Versus Dredging
Assume:
1. Dredging has a lifespan of 20 years, assuming that 1 foot of sediment is
uniformly removed over 150 acres and that external loading is reduced..
2. Alum treatment has a lifespan of 6 years.
3. Benefits are equal.
4. Dredging has a one-time cost of $500,000 ($2 per yd3). .
5. Alum treatment costs $35,000 every 6 years, assuming that the entire
area beneath the metalimnion (100 acres) is treated at a cost of $350 per
acre.
The annual cost method is often used to compare alternatives. The main ad-
vantage of this method over all other methods (such as present worth) is that it
does not require making the comparison over the same number of years when
the alternatives have different lives1. The equivalent annual cost is calculated as
follows:
Equivalent Annual Cost = Present Cost (Capital Recovery Factor)
The capital recovery factor is obtained from standard interest tables for
various interest rates and time periods. Figure 7-9 shows a typical table for an in-
terest rate of 6 percent. Based on the-assumptions described above, the cost,
analysis is as follows:
182
-------
Discrete Cash Flow
6.00% Discrete Compound Interest Factors
i
r! Single payments 1
N
i
2
1
14
5
6
7
8
9
10
••11
12
13
ID
15
16
17
18
19
20
22
2U
25
26
2B
30
12
3D
«
36
38
i *')
L «5
r -
1 60
65
70
75
80
85
90
91
100
Compound
Amount
P/P
1.0600
. 1216
. 1910
.2625
. 3382
.U1B5
.5036
.5938
.6895
.7908
1. 8903
2.0122
2. 1329
2.2609
2. 1966
2.5UOU
2.6928
2.85U3
3.0256
3. 2071
3.6035
«. OU89
<4. 2919
. U.5U9U
5.1117
5.7H35
6.U53H "
7.2510
•7.6861
R. 1M73
9. 15U3
10.2357
1.3. 76U6
18.U202
2U.6503
32.9877
1411. 1U50
59.C759
79.0569
105.796
1U 1.579
189.U65
253.516
339.302
Present.'.
Worth |
P/F i
0.911 3d
0..8910
0.8396
0.7921 ,
0.71173
0.7050
0.6651
0.62714
0.5919
0.55TI4
0.5268
O.U970
O.U68B
O.DI423
0.14 173
0.3936
0.371U
0.3503
0.3305
0. 31 18
0..2775
0.2H70
0.2330
0.2198
0.1956
0. 17U1
0.1550
0.1379
0.13T1
0.1-227
0. 1092
0.0972
0.0727
O.OSU 1
O.OU06
0.0 J03
0.0227
3.0169
0.0126
0.0095
0.0071
0.0053
0.0039
0.0029
, . Uniform series payments >
Sinking
Fund
A/F
i.roooo
•0. i)85UD
0'. 31«1 1
0. 22859
0. 177UO
0. 11 J36
0. 1191U
0. 1010U
O.C8702
O.C75S7
0.06679
0.05929
0.05296
O.CU758
0 .0«296
O.Q3895
O.C35UU
O.C3236
O.C2962
0.02718
O.C2305
0.01968
0.01823
0.01690
0.01D59
•0.01265
T.C1100
O.Q0960
O.C0897
0.00819
O.C.07,36
0.006146
O.COU70
0.003«U
0.0025U
0.001H1
O.C01 39
0.00101
O.C0077
O.C0057
O.COOU3
0.00032
0.0002U
0.00018
Compound
Amount
F/A
1 .000
2.060
3.18U
«. 375 '
5.637
6.975
8.39U '
9.897
1 1 . 14 91
13.181 '
H4.972
16.870
18.BS2
21.015
23.276
25.673
28.213
30.906
33.760
36.786
U3.392
50.816
514.865"
59. 156
68.528
79.058
90.890
10«. 18D
111.1435
1 19. 121
. 135.9014
15U.762
,212.71111
290.336
_39«.172
533. 128
719.083
967.032
1300. 9U9
'17U6.600
23U2.982
3H41.075
«209.10tt .
5638.368
Capital
Recovery
A/P
1.06000
0. 5«5ui4 '
0. 37U1 1
0. 28859
0.237i4'0
0.20336
0. 179114
0. 161014
0. 1U702
.0. 13587
0. 12679
0. 1 1928
0.11296
0. 10758
0. 10296
0.09895
0.095U14
• 0.09236
0.08962
0.08718
O.C8305
0.07968
0.07821
0.07690
0.07U59 "
0.07265
0..07100
0. 06960
0.06897
0. 068 39
0.06736
0. Of 6U6
P.06U70
0.063U11
0.0h25u
0. 061H8
0.06139
0.06103
P. 06077
0. 06057
O.P60M3
0.06032
0.0602D
0.06018
Present
Worth
P/A
0.9K311
1. IJ3 )U
2.67 30
3.U651
«. 21214
U.9173
5.592U
6. 2098
6.8017
7.3601
7. 8869
8. 3d38
8.8527
9. 2950
9. 7122'
10. 1059
10.U773
10.8276
-11. 1581
1 1. U699
1 2 . OU 1 6
12.550U
12.783«
1 3.0032
1 3. MP6?
1 3. 76U8
14.0800
Iti. 3681
11). U982
1«. 6210
1U. 8460
15.0M6 5
15.U558
15. 7619
15.9905
16. 161U
16. 2891
16. 38 M5
16.1558
' 16. 5091
16.5«B9_
16. 5787
16.6009
16.6175
N
1 '
.2
3
u
5
6
7
• 8
s ;
10
1 1
12
1 3
ID
15
16
-17
18 '
19
20
22 '"•
2«
25
26
?B
30
32
3«
35
36
38
1)0
1)5
50
55 . -
60
65 ,
70
75
80
85
90
95
100 '
Figure 7-9.—{From Blank and Tarquln, 1983.)
Annual Cost for Dredging Lake: From Figure 7-9 for a time period of 20
years (N=20), the capital recpvery factor is 0.08718. Therefore, the equivalent
annual cost is calculated as follows:
Equivalent Annual Cost = $500,000 (0.08718) = $43,590/year
Annual Cost for Alum Treatment: From Figure 7-9 for a time period of 6
years (N=6), the capital recovery factor is 0.20336. Therefore, the equivalent
annual cost is calculated as follows: .
Equivalent Annual Cost = $35,000 (0.20336) = $7,118/year
From this comparison, it is obvious that alum treatment is the more cost-effec-
tive alternative since the equivalent annual cost is $7,118 for alum treatment and
183
-------
$43,590 for dredging. Cost estimates for these treatments, while based on an
average of some actual case histories, cannot be applied, even as estimates, to
any other real lake situations. Each lake will have important and unique features
that will produce unique unit costs. . ,
Watershed Management Alternatives
Watershed management practices, described in Chapter 5, include controlling
runoff from agriculture and silviculture, stabilizing eroding shorelines, controlling
construction runoff, and repairing failing septic systems. Watershed management
also includes nonstructural practices such as the development of model erosion
and runoff control ordinances.
To be cost effective, watershed management practices should be directed
toward priority areas. Priority rating systems usually include factors-such as
proximity to lake, existing pollutant loadings, potential reductions in pollutant load-
ings, and costs. For small watersheds where specific, limited watershed manage:
ment alternatives can be identified, the evaluation and selection process is rela-
tively straightforward and can be performed as described later in this chapter.
However, for large, watersheds where only large-scale generic watershed
management alternatives such as agricultural practices or streambank erosion
control can be identified, the selection process is more complicated. For small
watersheds, the costs and effectiveness of management practices can be readily
estimated, but for large watersheds neither can be easily identified. Therefore,
selection of a management program for a large watershed is much more subjec-
tive and qualitative than for a small watershed.
By its very nature, a large watershed management program must be evolu-
' tionary and long term: first, priority areas are identified; then the most suitable
management practices are selected and implemented.
The watershed management information contained in Chapter 5 was used to
evaluate the effectiveness, longevity, and applicability of various watershed
management practices. .
Based on the results of the diagnostic portion of the study, the consultant for
Lynn Lake identified specific priority areas in the watershed. These areas in-
cluded the Middletown wastewater treatment plant, specific agricultural areas in
the watershed, and several developing areas of the watershed. Various manage-
ment practices for each high-priority area were identified and evaluated using the
criteria discussed previously. An evaluation matrix, shown in Table 7-6, was
developed to evaluate the various management practices. Information from
Chapter 5 and other reference sources was used to develop a rating based on
conditions specific to Lynn Lake such as land use, activity, soil conditions, topog-
raphy, and pollutant loadings. This matrix format can be used for decisionmaking
on any lake. The evaluations in Table 7-6, however, apply only to Lynn Lake.
Wastewater Treatment Plant Upgrade
Table 7-5, the annual phosphorus budget for Lynn Lake, indicates that the Mid-
dletown treatment plant (listed as WWTP) contributes 52.5 percent of the annual
total phosphorus income to Lynn Lake. In addition to being the dominant phos-
phorus source, the treatment plant discharges phosphorus primarily in the form of
soluble reactive phosphorus, a form readily available for algal and weed growth.
Also, the plant discharges this highly available phosphorus throughout the year,
even during summer low flow conditions. It is important, therefore, that this phos-
phorus source be significantly reduced.
There are two alternatives for eliminating or reducing the phosphorus entering
the lake from the treatment plant: diverting the plant effluent to another watershed
184
-------
that is not adversely affected by high phosphorus levels or providing tertiary treat-
ment to remove a significant portion of the phosphorus from the plant's effluent.
Diversion.of the treatment plant's effluent to ahother'watershed was rejected be-
cause the pipeline and pumping station needed for .the diversion would cost ap-
proximately $400,000—more than the cost of adding tertiary treatment to the
plant. It was also rejected because the citizens in the adjacent watershed op-
posed the diversion of effluent td their watershed.
The addition of tertiary treatment facilities to the existing secondary treatment
plant would reduce the effluent phosphorus concentration by 75 percent, from 2
ppm to 0.5 ppm. The tertiary treatment facilities would include the addition of a
sand filter and alum treatment to the existing plant. Addition of the tertiary
facilities would cost approximately $300,000~for the 100,000 gallon-per-day treat-
ment plant. Operation and maintenance costs would increase by about 25 per-
cent primarily because of increased chemical and sludge disposal costs.
As shown in Table 7-6, the addition of tertiary treatment facilities to the Mid-
dletown plant was rated excellent for all categories except capital cost and opera-
tions and maintenance cost. Although the cost of tertiary treatment is high, this
approach must be implemented to reduce the dominant phosphorus load to Lynn
Lake.
Sedimentation Basins •
An effective practice for controlling sediment and phosphorus loads to Lynn Lake
is the construction of sedimentation basins on the major tributary streams, just
upstream of the lake. As shown in Table 7-6, the basins were rated "good" overall,
except for the costs, which were rated "fair." Construction of the basins would be
cost effective only if upstream watershed management practices were not imple-
mented or were not effective. Construction of the basins, therefore, was rejected
and postponed until upstream management practices could be implemented and
evaluated. If additional sediment and phosphorus load reductions were required
after upstream management practices were implemented, then the construction
of the sedimentation basins should be reconsidered.
Agricultural Practices
The ratings of agricultural practices, shown in Table 7-6, were developed in con-
junction with the U.S. Soil Conservation Service and the County Conservation
District. Priority management practices were determined based on these ratings
and included animal waste management, grassed waterways, buffer strips, and
conservation tillage. Secondary emphasis was given to pasture management,
crop rotation, and runoff diversion. The Soil Conservation Service was contacted
for information on the low input-sustainable agriculture.program and this informa-
tion was given to the farmers in the watershed. The Soil Conservation Service
worked with the farmers to develop multiple use programs that would actually
sustain yields while reducing erosion and nutrient input to the" streams feeding
Lynn lake.
Construction Controls
Construction-development controls were divided into three general categories:
• Erosion control ordinance
• Runoff control ordinance •
• Field inspections.
185
-------
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186
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An,erosion control ordinance provides rules and guidelines to regulate the
control of erosion from art active construction site. Although the State has an or-
dinance to control erosion on constructidn .sites, the Advisory Committee recom-
mended that the county enact a county-wide erosion control ordinance more
restrictive and enforceable than the State ordinance. In general, control of erosion
should be a local, not a State regulated function.
A runoff 'Control ordinance, in contrast to an ^erosion control ordinance,
provides rules and guidelines for controlling runoff and erosion from new develop-
ments after construction is completed. The consultant developed a runoff control
ordinance that required that the peak postdevelopment stormwater runoff rate not
exceed the peak predevelopment runoff rate. It also contained an equation for es-
timating the phosphorus load from the new development and stipulated that the
postdevelopment phosphorus load not exceed the predevelopment load.
No ordinance is effective if it .is not adequately implemented and inspected.
Field Inspections of all construction sites during and after construction are neces-
sary to ensure that all ordinance'conditions are being met. All three construction-
development controls (that is, erosion control ordinance, runoff control ordinance,
and field inspections) were rated excellent in all categories in Table 7-6. Im-
plementation of all three controls will eliminate or significantly reduce runoff and
erosion problems for new developments.
In summary, the watershed management program recommended by the Ad-
visory Committee consisted of the following:
• Addition of tertiary treatment facilities to the Middletown treatment
plant; -
.• Implementation of priority agricultural practices in priority agricultural
areas; . •
• Development and adoption of erosion control and runoff control
ordinances; and
• Development of a field inspection program fpr construction and
development sites. . .
After these practices are implemented, the annual sediment and phosphorus
loads to Lynn Lake would be re-evaluated to determine whether additional prac-
tices, such as the construction of sedimentation basins, are needed.
In-Lake Management Alternatives
In-lake management practices applicable to the control of excessive algal and
weed growth and loss of depth were identified and evaluated using the informa-
tion contained in Chapter 6. Each management technique was evaluated based
on the lake and watershed data collected during the study. The results of this
evaluation, presented in Table 7-7, indicate that the most feasible and cost-effec-
tive in-lake management practices include the following:
• Alum treatment to precipitate and inactivate phosphorus
• Dredging of the fake inlet areas.
Alum treatment, after the addition of tertiary treatment to the Middletown treat-
ment plant, was selected because the study data indicated that internal cycling of
phosphorus from the lake sediments was a source of phosphorus to Lynn Lake.
187
-------
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188
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The lake characteristics are conducive to alum treatment: the flushing rate is low
(0.45 times per year) arid the annual phosphorus loading after watershed
management practices are implemented will be relatively low. Lab studies were
performed to determine the alum dosage required to both remove phosphorus
from the lake water and to inactivate (seal) the phosphorus in the sediments. Ad-
ditional alum treatments may. be required every six years based on case studies
of other similar lakes treated with alum.
• Alum treatment on a three- to five-year basis was compared to dredging of the
whole lake using the cost comparisons described earlier. Alum treatment was
judged the most cost-effective method of controlling phosphorus from lake sedi-
ments. If, however, a secondary benefit—lake deepening-^was added, dredging
of the whole lake may be the most cost-effective alternative. However, since Lynn
Lake is deep enough for its intended recreational uses, lake deepening was
rejected as a benefit, and alum treatment was selected as the practice to inac-
tivate phosphorus in the sediment.
Dredging of lake inlet areas, however, was selected as a feasible manage-
ment practice since the siltation of the lake primarily affected the inlet areas that
were shallow and unusable for boating. Many of the aquatic weeds also grow in
these inlet areas.
Other in-lake practices were rejected for a variety of reasons. Dilution and
flushing were rejected because a source of dilution water was not available.
Pumping of groundwater to flush and dilute the lake was rejected because of high
costs and the potential depletion of groundwater. Aeration of the whole lake was
rejected because of the lack of confidence in the practice and the high capital and
operation costs. Insufficient data are available on the effectiveness of whole lake
aeration. Hypolimnetic aeration (aerating only the bottom waters) was rejected
because it was evaluated "fair" in all categories except costs, which were rated
"poor." Sediment oxidation was rejected because of the "poor" confidence rating;
insufficient data are available on the effectiveness of sediment oxidation.
The addition of algicide was rejected because it is a "Band-Aid" approach that
has poor longevity and produces negative environmental impacts. Algicide, how-
ever, can be added on a temporary basis while the watershed management pro-
gram is being implemented but should not be used as a long-term management
program. Weed harvesting and the addition of herbicides were also, rejected for
similar reasons.
Food chain manipulation was rejected because the longevity and negative im-
pacts are unknown and the confidence level was rated "poor." Biological controls
to reduce weeds were rejected to avoid introducing exotic species to the lake.
Water-level drawdown, although it was rated "good" for effectiveness, was
rejected because the citizens did not want the lake water lowered.
Hypolimnetic withdrawal, the discharge of nutrient-laden bottom waters, was
temporarily rejected because of concern over potential downstream impacts and
possible in-lake effects on the thermal stratification of the lake. Discharge of bot-
tom waters high in nutrients and low in dissolved oxygen could adversely affect
water quality downstream of Lynri Lake. The Advisory Committee decided that
these potential impacts should be further investigated before a bottom discharge
would be allowed.
In summary, the in-lake management program recommended by the Advisory
Committee consisted of the following:
• Alum treatment to precipitate and inactivate phosphorus
, • Dredging of the lake inlet areas.
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Public Hearing
Prior to the final selection of watershed and in-lake management alternatives, the
Advisory Committee held a formal public hearing. The consultant presented an
overview of the study along with a description of the conclusions and proposed
management plan. In describing the proposed management program, the con-
sultant clearly explained the evaluation criteria used in developing the plan. Com-
ments from the public on all aspects of the study and management plan were
solicited by the Advisory Committee.
In general, the public comments were positive and supported the proposed
management program. Some questioned whether the restoration program would
cause an increase in county taxes. Others wanted to know whether their
sewerage fees would increase when the treatment plant was upgraded to tertiary
treatment. They Were told that county taxes would not increase but that the
sewerage hookup fees and user fees would increase by a small amount. Some
wondered if fishing would be adversely affected by the proposed plan. It was ex-
plained that the alum treatment and inlet dredging would shift the lake from an
eutrophic to a mesotrophic state. Although less productive, the mesotrophic lake
conditions would primarily benefit game fish production and would enhance fish-
ing.
Several citizens recommended that the monthly monitoring results for the
treatment plant's effluent be sent to the county and the Advisory Committee to en-
sure that the plant met it's treatment requirements. Others recommended that the
Advisory Committee be maintained until the management plan was completely
implemented and that the county hire a full-time lake manager to oversee the pro-
gram. The Advisory Committee directed the consultant to include these recom-
mendations in the final management plan.
Selection of Management Plan
The Advisory Committee, in conjunction with the consultant, .presented the final
lake and watershed management plan to the County Commissioners for review.
After they revised the plan, the Commissioners approved the plan and directed
the County Engineer to forward the Phase I Study Report-and Management Plan
to the State Water Control Board and EPA for their reviews. The plan was ap-
proved by both the State and EPA.
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Chapter 8
IMPLEMENTING A
MANAGEMENT PLAN
Management Means
Implementation
A well-evaluated and carefully designed management plan is useless if it is never
carried out and may be either useless or disastrous if it is poorly followed.
Management includes not only diagnosing problems and evaluating alternative
solutions but also putting the chosen plan into action.
Proper implementation requires money, manpower, planning, scheduling, and
permission/Even on private lakes, various permits and regulations must be satis-
fied before many lake restoration techniques can be applied. If the watershed is
not entirely owned by a single lake user, coordination among parties becomes a
sizable task in itself. And, in all cases, education is a necessary counterpart to ac-
complishment. Never assume that the majority of residents will be aware of the
major and minor disruptions to their tranquil lake environment that will occur once
implementation begins. Publicity on not only the goals of the project but the pro-
cedures used to reach them will foster both public support and patience during
the implementation phase. .
Who Does the Work?
For many lake managers, homeowners, and other interested persons, the most
important step in implementation is the selection of a knowledgeable and ex-
perienced consultant or contractor. It is at the implementation stage that the
benefits of experience become obvious. There can be frequent opportunities for
delays, minor accidents, misunderstandings, and oversights in a restoration
project. Experienced contractors are more likely to foresee these problems and
be better prepared to handle unexpected ones.
The person who pays the contractor has responsibilities a"s well. For example,
an association may hire a lake manager or consultant, who, in turn, hires contrac-
tors to carry out various tasks and represents the owners' interests. The
191
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manager's responsibilities include overseeing the budget, monitoring progress to
ensure-the project is on schedule, and acting as liaison between the association
and the contractor to be sure that both sides understand each other's intentions
and that work is not delayed while the contractor awaits important decisions. •
Selecting Consultants or Contractors
Selecting the right consultant or contractor involves a number of considerations.
The criteria used in Chapter 3 will ensure that the selection process identifies
qualified contractors who have a responsible record and the right background to
solve the particular problem. Table 3-3 in Chapter 3 also includes criteria for
selecting a consultant who will be able to assist in other phases of lake manage-
ment such as identifying the problem, evaluating watershed and lake manage-
ment practices, and formulating the lake management plan as well as implement-
ing the plan once it is developed.
Consulting services can range from assistance in one specific area such aS
lakeshore erosion, to the design, execution, and implementation of the entire lake
management program. The expertise required for lake management can be spe-
cialized or broad, depending on the specific services requested, but should in^
elude limnology or aquatic ecology, watershed management practices, Jake res-
toration techniques, economic analysis, planning, engineering, and water quality
evaluations. Many lake associations prefer to work with a single firm from the
preliminary study to project completion, but it may be wise in some cases to hire
more than one consultant to take advantage of the strengths and specialties of-
fered by different providers.
Experts on lake restoration can be found at universities, public and private re-
search organizations, environmental consulting firms, or engineering firms
specializing in lake management. Many firms or groups that specialize in lake
management can put together teams of skilled individuals with special experience
who can target a specific set of lake problems. In this case, the consultant or con-
tractor may change team, members as needed to accomplish the'work most effi-
ciently. The members of this team and the consultant shogld be familiar with local
'and State regulations, local and regional lake problems, and the management op-
tions that work in your type of lake and region of the country. The North American
Lake Management Society has a list of members who can provide services by
area of specialty and section of the United States.
Initially, candidate consultants and contractors can be identified by contacting
(1) other lake associations to find out who they have used previously, (2) local
and State environmental agencies and groups to find out who has conducted
similar studies in the past, (3) a referral service offered through NALMS, or (4)
societies for professionals in these trades. Appendix E provides more detailed in-
formation on various lake management programs in the States and Canadian
Provinces. Because of the importance of the consultant or contractor in properly
implementing the lake management program; several individuals or groups
should be interviewed. The criteria listed in the case study in Chapter 7 can be
used as a starting point for questions related to their expertise and capabilities.
Asking for references is imperative. The hiring agency should write, or better
yet call, these references in addition to evaluating the responses of candidates to
interview questions. Lake management is not .a cookbook process; there is some
art to lake management as well as engineering and science. Innovation should be
an important criterion. There are, however, certain important components in im-
plementing any lake .management program. These are discussed in the
remainder of this chapter. This information also can be used to initiate questions
for the consultant during the evaluation and selection process.
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Institutional Permits, Fees, and
Requirements
Every State and many Federal agencies have institutional requirements (for ex-
ample, permits, fees, and notifications) that must be met before lake restoration
or watershed management practices can be implemented. Some of these re-
quirements are briefly summarized in Appendix E. DO NOT assume this is a com-
plete list of all the agencies that need to be contacted. Local, city, and county
agencies might also require various permits or fees or fulfillment of necessary
conditions, and these requirements and agencies change through time. Obtain a
recent list of permits, fees, or other requirements.
These institutional requirements, in many instances, are technique specific as
well. The requirements for dredging, for example, will be quite different from those
for herbicide application or harvesting. The U.S. Army Corps of Engineers is
authorized, after proper notice and public hearings, to issue general permits to
permit dredging or fill procedures if, in the Corps' determination, the dredging
operation will have minimal adverse environmental effects.
. If. a State has assumed permit responsibility, a copy of every permit application
is forwarded to the U.S. Army Corps of Engineers. Copies also are forwarded to
the Secretary of the Interior and the Fish and Wildlife Service. Some States may
have additional requirements, such as the State of Washington, where an ap-
plication must be made to the State Department of Game for a hydraulic permit
for any.alteratipn of the stream or lake bed, including the installation of a flow- or
temperature-measuring device.
In a lake restoration plan that calls for dredging, taking the sediment out of the
lake represents only one part of the implementation process. The dredged
material, or spoils, must be properly disposed of as fill or taken to an. approved
disposal area. Disposal procedures must conform with local, State, and Federal
requirements, which might require monitoring of the runoff (leachate) from the
disposal area. •
In addition to requirements for implementation of the various techniques, there
are also various Occupational Safety and Health Administration requirements to
protect the health, well-being, and safety of the individuals working on the project.
Ear protection and safety shoes might be required for the dredge workers, for ex-
ample, or special safety precautions might be mandated to protect workers while
they are mixing chemicals for alum applications or dispersing herbicides for weed
control. An example of the language that can be included in contracts to promote
and ensure a safe implementation program is shown in Appendix F. DO NOT as-
sume this language will satisfy the legal requirement in your State or county. Con-
tact a local attorney to be sure you are adequately covered.
The institutional requirements for each lake management program will depend
on the specific restoration and management practices proposed. If the lake
management plan is well organized and detailed beforehand, the various agen-
cies will be able to indicate the specific procedures and guidelines that must be
followed. Even if the lake manager or association is researching and filing for all
permits and fulfilling other requirements, it makes sense to ask consultants and .
contractors if they are familiar with the appropriate regulations and agencies for
the proposed lake management project. The degree of help and completeness of
information may be excellent in some government offices. Other offices give out
pertinent information more grudgingly, and only if the right questions are'asked.
The contractor's previous experience will be; especially valuable if this latter situa-
tion-is the case.
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Implementation Costs Money
Two questions that arise from this statement are "How much will it cost?" and
"Is there funding available to implement this project?"
Plans and Specifications
The first question can be addressed by having the consultant or contractor,
lake manager, or interested groups or individuals develop a set of plans and
specifications for the various lake management techniques that are feasible.
Economic considerations were part of the evaluation that preceded choosing a
management alternative, so a rough approximation of cost is already available.
At implementation, this estimate can be refined by pricing materials and man-
power needed; calculating the cost of the time required for implementation,
equipment needs, and any construction prior to implementation; and, finally,
estimating the cost of a postrestoration monitoring program.
The cost of postrestoration monitoring should be factored directly into the
overall cost of implementation because it is the only approach for evaluating
whether treatments are effective. . •
The preliminary set of plans and specifications does not have to be ex-
tremely detailed because it will be revised before it is let for bids, but it should
provide sufficient information to approach potential funding agencies for
money.
Funding Sources
Federal Agencies
For lakes with public access, the Clean Lakes Program, administered through
the U.S. Environmental Protection Agency (EPA), is a source of funds both for
diagnosis and evaluation of lake problems and also for implementation of lake
management programs. Section 314 of the Clean Water Act provide for Phase
I (Diagnostic/Feasibility Studies) and Phase II. (Implementation) management
programs to improve lake water quality. Much of the work discussed in this
Manual came out of Clean Lakes studies. ,
Contact the State agencies listed in Appendix E for information on their
programs.
Funds also .might be available from other Federal agencies for various
aspects of lake management:
Q One of the most innovative Federal programs has been the Rural
Clean-Water Program, which began in 1980 as a 15-year experiment
.to control agriculturally generated nonpoint source pollution at the
local level. Many lakes have benefitted from the RCWP's objective of
improving water quality. Based,on interagency cooperation, the pro-
gram is administered by the U.S. Department of Agriculture's (USDA)
Agricultural Stabilization and Conservation Service (ASCS) in consult-
ation with EPA. The Soil Conservation Service has contributed techni-
cal expertise, with national, State, and local committees making the
major program decisions.
194
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Q Soil and water conservation are encouraged by grants and cost shar-
ing'through the ASCS. Cost sharing enables communities to design
management systems to improve water quality and stabilize runoff of
nutrients or soils. Longer-term agreements would allow for preserva-
tion of wetlands areas. An advisory service to improve flood preven-
tion, streambank protection, and wildlife protection is also available.
Q Guaranteed and insured loans also are available through USDA's
Farmers Home Administration to improve farmland and watersheds
through soil conservation, treatment of farm wastes, and reduction of
runoff into receiving waters.
Q The Department of Agriculture's Forest Service offers research grants
and financial assistance to improve watershed management. Studies
that determine the fate of pesticides and fertilizers after they have
been applied to forests. Reforestation and habitat improvement re-
search studies are also funded.
Q Loans and project grants are available through the Economic
Development Administration of the Department of Commerce to en-
courage economic improvements in financially depressed areas. Sup-
port for better water and sewage facilities helps to improve the water
quality of lakes and streams. In some instances, cities or regions that
have strong, organized offices of economic development have spon-
sored or provided assistance in lake projects. '
Q The Department of Housing and Urba,n Development supports a
broad range of planning and management activities to improve land
management and protect natural resources.
•Q The Department of Interior's Office of Surface Mining Reclamation
and Enforcement makes available grants to States to restore lands
and waters affected by pre-1977 coal mining. The 1977 Federal Sur-
face Mining Law makes mine operators responsible for protecting the
environment during coal mining and reclaiming the land afterward.
Q Interior's Bureau of Reclamation improves recreation development
and flood control and aids in protecting municipal and industrial water
supplies through project grants and loans.
Q The U.S. Fish and Wildlife Service oversees habitat development and
enhancement of fisheries resources and researches the effect of pes-
ticides on fish and wildlife through formula grants.
QThe U.S. Geological Survey offers help to the States through
cooperative programs that provide 50 percent matching grants to in-
vestigate the physicochemical properties of the State waters as well
as the geology and quantity of streamflow from watersheds and
basins. This agency also manages'the State Water Resource Re-
search Institute Program, which can be of great assistance to lake
restoration efforts.
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State Agencies
EPA's Clean Lakes Program has encouraged the development of lake
management programs in many States. Most are modeled after the Clean
Lakes Program; some administer the Federal program for their States, others
fund projects independently. The funding status of state programs is shown in
Appendix E. Funding varies annually, so these agencies need to be contacted
well in advance of deadlines for submittal of grant requests to determine their
current or projected funding status.
Each State and territory has a designated State Water Resource Research'
Institute or Center on the campus of at least one land grant university. Nearly
all these universities have staff and libraries that can be of great assistance to
individuals or groups seeking information about restoration programs such as
the State agencies involved, the rules and regulations involving shoreline
development, in-stream and lake manipulations, dredging, and application of
chemicals to lakes. In most instances staff will be aware of assistance
programs to implement a restoration project. Each institution or center also has
contact with, or directories of, the more prominent lake researchers and agen-
cy personneMn the State or territory.
Local Funding Sources
In some States, lake management districts have been authorized with enabling
legislation that permits millage or tax assessments. Watershed management
districts, irrigation districts, conservation districts, or sewer districts may have
the authority to fund watershed or lake management plans that will improve
lake quality. Private foundations might have funds available for particular
aspects of lake management such as nature conservancy (for example,
preserving or enhancing wetlands around a lake) or other considerations.
Local clubs, organizations, or community agencies might provide funds or
sponsor fundraising activities. For example, if fishing is a desired lake use,
local fishing clubs might be interested in sponsoring a fishing tournament, com-
munity dance, or other activity to raise money.
Local activities can raise significant amounts of money. The small com-
munity of Republic, Washington, raised $25,000 in direct contributions to meet
a State matching requirement to fund studies on nearby Curlew Lake.
For many grants or awards, a fund-matching arrangement requires the
recipient to raise a percentage of revenue to qualify. This matching money,
' however,.does not have to be out-of-pocket cash. Often, in-kind services are
credited with a value in lieu of actual monies. Contributed time at an approved,
audited rate can satisfy the matching requirements. City, county, or State agen-
cies, for example, might provide an in-kind match by filing permit applications,
coordinating public meetings, or monitoring restoration activities or other
aspects of the project.
Volunteer help from lake association members or interested citizens is in-
valuable, particularly where Federal or State funds cannot be obtained. Many
lake restoration projects have been effectively conducted by using volunteers
and equipment donated" by local contractors: a flotilla of fishing boats for alum
treatment; local contractors with backhoes and dump trucks for dredging; and
youth groups to plant sod or other vegetation to stabilize stream banks or
shoreline. Every option should be considered for lake restoration.
Once funding sources have been identified, the project can be submitted to
prospective consultants and contractors for bids.
196
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*
Implementation Requires
Contracts
Invitations to bid can be announced locally, but because lake management is a
specialized area, it is generally better to announce the invitation to bid at the
State or regional level. Various organizations have newsletters that are read by
lake management contractors and consultants, so it is a good idea to also con-
sider placing-an announcement there. Potential contractors or consultants
should include a list of their qualifications with their bids. In the invitation to bid,
.a minimum set of qualifications should be specified as a prerequisite to con-
sideration. Prequalification prevents contractors from wasting their time sub-
mitting'bids on projects for which they are not competitive and reduces the
time the lake manager has to spend reviewing bids.
Evaluation,of the bids and selection of the contractor should be based on
the quality of the proposed work as well as price. The lowest cost will not al-
ways result in the desired lake quality. A local attorney familiar with engineering
contracts can be used to prepare a contract or review the contract submitted
by the individual or firm selected.
The person preparing the contract should consider including a requirement
•for a contract bond and liability insurance. A contract bond guarantees that the
work or implementation of the lake management plan will be completed in ac-
cordance with the contract documents (that is, the lake management plan with
associated specifications) and that all costs will be paid. Examples of a bid
bond, payment bond, and performance bonds are included in Appendix F.
These are examples only, contact a local attorney for a legal contract.
Implementation Takes Time
Inclement weather, unanticipated obstacles, and other factors can delay the
implementation of the lake management program. Some of these delays may
be unavoidable, but their impact can be minimized. One of the first products
the successful contractor or consultant should deliver is a detailed project
schedule and contingency options for every critical activity. A critical activity is
one that must be completed before another can proceed or be finished. For ex-
ample, a restoration plan that includes dredging will come to a complete stop if
the business of acquiring and preparing an approved disposal site is not begun
early enough. Until the disposal site is ready, nothing can come out of the lake.
Smooth implementation depends on careful scheduling. Not only do critical
activities need to be .timed to one another, but convenience, ideal operating
conditions, and maximal efficiency should also be kept in mind! It is better to
plan dredging to coincide with a time of year when usage is low but the lake is
accessible, such as fall or early winter, which allows for maximum boating
safety, .as well. In colder climates, dredging can occur in the winter using con-
ventional construction equipment such as bulldozers and drag lines. The lake
can be drawn down in the fall and the sediments allowed to consolidate and
freeze before removal. This permits the use of volunteer labor and local con-
struction contractors or operators for sediment removal, which can decrease
expenses. Alum treatment can be scheduled (1) for.late spring following the
major spring thaw to aid in inactivation of new nutrient .input, (2) in the fall to in-
tercept the release of nutrients from decaying macrophytes, or (3) after dredg-
197
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ing to inactivate suspended phosphorus and reduce exposure of rich sedi-
ments to overlying water columns. Watershed manipulation such as streamr
bank revetment or levee construction can best be accomplished when water
flow is low. Implementation of streamside management zones should coincide
with the peak growing season so that vegetation can become established
before winter.
Scheduling programs are available for personal computers that permit daily,
weekly, or monthly tracking of the project's progress. These programs can be
revised quickly to determine the impact of delays oh project implementation
and reschedule other activities to minimize these delays. The lake manager
should review these schedules on a weekly .basis during peak construction or
implementation periods.
The lake manager, contractor, or other-interested party should audit the
project's progress and expenditures at least quarterly to determine if the
budget is living up to the schedule. • .
Monthly progress reports should be required for the contractor.
Public Education is Critical for
Sound Lake Management
Public education must begin before implementation ever occurs, but it is par-
ticularly critical during implementation. Various desired lake uses generally are
partially restricted while restoration is in progress. Activities such as shoreline
stabilization,, alum treatment, and dredging restrict lake usage. People typically
respond positively when they understand what is occurring and why. People
react negatively when they are uninformed.
In many States, public meetings are a requirement for lake restoration
projects. Every opportunity should be used to discuss progress in all phases of
' lake restoration at lake association and lake homeowner meetings. It is essen-
tial to prepare lake residents and users for what may take place during the im-
plementation phase.
Materials, including slides, films, and videotapes of other projects, may be
used to familiarize the public with the type of equipment and procedures that
will be used during lake restoration. NALMS can provide a videotape or slide
show on lake management for use in a public information program.
Postrestoration Monitoring is an
Integral Part of Implementation
The greatest current deficiency in lake management is the lack of information
on treatment longevity and effectiveness; postrestoration monitoring can supp-
ly this data.
Results from lake management and restoration projects are not always ob-
vious to the naked eye; monitoring can help identify changes in the lake and
whether or not the trend is toward improvement. If monitoring shows that ah
improvement is not occurring, the data can be used to help diagnose,the
cause. In addition, restoration projects can result in a short-lived improvement
because some factor not accounted for in the restoration plan is counteracting
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the work that was done. By maintaining' a continuing monitoring program, such
problems can be detected as they develop. - •
, Monitoring is one of the most cost-effective activities of the entire lake
management program. Monitoring, however, does cost money; the amount is
directly related to the number of stations, the number of samples, the number
of variables, and the sampling frequency. The number of stations and depths
was discussed under Sampling Sites in Chapter 3. In general, for oval or round
lakes a single station over the deepest point in the lake might be satisfactory.
Additional stations will be required as the lake or reservoir becomes more ir-
regular, with multiple coves and embayments, or much longer and narrower.
To assist in the design of a postrestoration-monitoring program (for ex-
ample, parameters to measure, the frequency of measurement, location and
depth in the lake, inflow and outflow), a technical supplement on monitoring,
Monitoring Lake and Reservoir Restoration (Wedepohl et al. 1990), was
prepared to complement this Guidance Manual. The technical monitoring sup-
plement discusses appropriate parameters to measure for different types of
lake problems and management techniques, the relative cost of these
parameters, and how to prioritize parameters. The supplement also provides
guidance on interpreting and presenting the monitoring results.
Regardless of the question asked or problem addressed, there is no sub-
stitute for data. Table 8-1 explains briefly where samples are-taken for com-
monly measured chemical and physical data.
The reliability of the.conclusions drawn from monitoring data is directly re-
lated to its quality. There are well-established and accepted methods and pro-
cedures for chemical analysis of water samples as well as for quality as-
surance and quality control of the analyses. It is imperative that the laboratory,
consultant, or contractor who collects and analyzes these samples use ac-
cepted methods and standard quality assurance/quality control procedures. In-
quire about their methods and ask to see the quality assurance/quality control
results from previous water quality analyses on lakes or streams. Laboratories
that analyze sewage might not be able to analyze lake water samples because
the constituent concentrations may be 100 to 1,000 times less than waste—
water. Test kits are appropriate for some analyses but should not be used for
most routine water quality examinations. Water quality analyses cost money;
make sure the quality of the data warrants the expense.
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Table 8-1.—Long-term monitoring requires proper siting and appropriate selec-
tion of parameters .. ^
LONG-TERM MONITORING CONSIDERATIONS •_
SITING
Ambient Water Generally, one site overthe deepest part of the lake. Should not be near a
Quality dam, close to shore, of near stream inflows or point source influents. Lakes
with distinctive subbasins, coves, fingers, or multiple inlets may require
• additional sampling sites (see Chapter 3)
Budgets • Flow rates, water levels, and concentrations can be measured on major tri-
butaries and estimated on minor inflows. Accurate assessment of lake vol-
ume be necessary to account for nonpoint source loading and runoff vol-
ume entering the lake. Nonpoint sources are difficult to monitor; a profes-
sional will base siting on lake-specific hydrology, -basin morphometry and
other factors. Reference land-use-based export coefficients can provide a
good first approximation, often sufficient to disguise problems. Budgets
are usually limited to diagnostic studies, but long-term monitoring may be
employed to track success of a restoration project or management technique.
Sources Monitoring sites can usually be limited to major inflowing streams or point
source outfalls to the lake or tributary—particular^ near suspected sources
of sediment, nutrients, organic matter, or chemicals. Unless a special
problem or land use exists, rates from these stations can be used to inter-
polate rates from minor inflows. In seepage lakes, groundwater obser-
vation wells may be necessary.
PARAMETERS
Complete Water Samples taken from two depths (1 ft below surf ace and 2ft above
Chemistry lake bottom)
The following constituents are commonly measured, but a professional
may recommend additional (or fewer) constituents:
Priority Group
Dissolved oxygen
Total phosphorus •
Total nitrogen ,
pH ' .
Total alkalinity
Turbidity
Total suspended solids
Other Parameters Commonly Measured •
Ammonia nitrogen Kjedahl nitrogen
Nitrate-nitrite nitrogen '. Chlorine
Dissolved phosphorus Calcium
Magnesium Sodium
Potasium ' ' • Sulfates
lron Manganese .
Total dissolved solids Volatile solids , •
Color
Total Sampled at two depths (1 ft below surface, 2 ft above bottom) during late
Phosphorus winter to spring turnover; during growing season sampled at three depths
(surface, bottom, and at top of hypolimnion). Multiple measurements near
the surface are a priority
WaterTemp- These parameters are profiled, or recored along a vertical axis (the water
erature column), from 1 ft below surface and at 3-6 ft intervals to the bottom. Meter
pH ' is required to measure pH and conductivity
Conductivity
Chlorophyll-a Measured at 1 ft below lake surface, and as important as phosphorus
Secchi Extremely useful and simple measurement; minimal sampling schedule
Transparency can be inexpensively upgraded to weekly sampling with
volunteer observers ,
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Table 8-1.—Long-term monitoring requires proper siting and appropriate selec-
. tion of parameters (cont.) ' .
LONG-TERM MONITORING CONSIDERATIONS
OTHER USEFUL MEASUREMENTS
Lake Water Frequency can be increased to weekly observations at low cost by using
, Level volunteer observers; volunteer programs to observe water levels during
storm events, however, are difficult to conduct. If intensive sampling is
required for a diagnostic study, automated equipment is generally used
Fish Survey Netting during spawning season, boom shocking after Sept. 1. Electro-
. shocking every other year. Gill netting every sixth year. Obtain advice from
State or local agency or fish and wildlife department
Macrophytes Surveyed every third year for abundance and location by species during
peak growing season, late summer
Phytoplankton Water collected at 1 ft depth with water bottle to identify species and gen-
eral abundance
Zooplankton A vertical tow is made with a plankton net for identification and general •
bundance
Macro- •
invertebrates Sampling is conducted in late winter in the lake and inflowing streams
Watershed Inventory of existing land use with field verification (on-site observation
Map and walking tours). Updated every 3 to 5 years, as necessary, can provide
an excellent record of potential sources both for tracing the origin of prob-
lems and planning to prevent problems
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m
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Chapter 9
LAKE PROTECTION AND
MAINTENANCE
*
Introduction
Fishing, swimming, boating, hiking, watching a sunset or a sunrise over the water,
sitting on the shore—all are activities that occur in and around lakes. Water at-
tracts people, and, if uncontrolled, this attraction can eventually result in impair-
ment of water-based recreation. This Manual is directed primarily at restoring
these desired lake uses. Obviously, the best solution would have been to prevent •
the degradation from occurring. Now, the object is to prevent these problems from
occurring again once the lake is restored. ''-.--
This chapter discusses some of the approaches that can be used to protect
and maintain desired lake uses. These approaches range from informal backyard
discussion of lakeshore maintenance or aquatic weeds to the passage of laws to
protect lakes. The key to lake protection and maintenance in all of the ap-
proaches, however, is public involvement and organization.
Lake Organizations
The protection and maintenance of lakes depends on the ability of lakefront
property owners and lake users to identify their own interests and form an as-
sociation to pursue these interests. Many lake associations are organized in
response to lake crises such as nuisance weeds, fishkills, foul odors, or pollution
from watershed development. People recognize that they can accomplish more
as an organized group than they can individually, and this rationale holds true for
lake protection and maintenance. Preservation of a lake, its water quality, and the
desired lake uses is far more prudent than restoration, and it is certainly more
cost effective.
Lake organization activities range from holding informal meetings of
homeowners to share information about the lake, to monitoring the.passage of
enabling legislation to form special districts to protect and improve lakes. Wiscon-
sin lake districts, for example, have the power to-tax, levy special assessments,
203
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borrow and bond to raise money, make contracts, and other like authority to
protect and improve their lakes. The critical element is the formation of the lake
association. If your'lake does not have a lake association, identify several people
who share your interest and concerns and form a steering committee. There is a
pamphlet available from the North American Lake Management Society
(NALMS)—Starting and Building an Effective Lake Association—that can help
you get started. '
Two of the primary purposes of all lake organizations, however, should be
educating the public and promoting increased involvement in lake management.
The more informed people are about lake problems, alternative management pro-
cedures, and watershed effects, the more intelligent their decisions will be about
selecting and implementing appropriate protection and maintenance procedures.
This information is available from a variety of sources including those listed in
Chapter 8 and Appendix E. State Departments of Natural Resources or Environ-
ment, Game and Fish staff, and county Cooperative Extension agents generally
are willing to provide written information or talks to organizations about various
aspects of lake or watershed management practices. Local university professors,
consulting firms, or members of environmental groups can discuss ongoing or
completed projects at other lakes in the area. Video cassettes, slide presenta-
tions, brochures, and other information on lake protection and restoration can be
obtained from EPA and NALMS, which can also'provide the name of the NALMS
State contact and a list of members who have volunteered to speak about lake
management and restoration. Local, State, and Federal officials also can be
called upon, to discuss some of the regulatory procedures available for protecting
and maintaining lakes.
Regulations for Lake and
Watershed Protection and
Management Activities
Reasonable and appropriate regulations can be an important part of a water-
shed-lake protection and management plan. These regulations can be adopted
for three general purposes: (1) protecting the lake by regulating watershed ac-
tivities that cause erosion and pollution problems (the point and nonpoint source
controls discussed in Chapter 5); (2) controlling development to protect the aes-
thetics and benefits of the shoreland; and (3) regulating the lake usage to reduce
conflicts among swimmers, boaters, fishermen, and others (Born and Yanggen,
1972). Some of the most serious lake problems occur because of conflicts among
lake users. . -
Controlled Development
Many of the same regulatory activities developed for other situations such as
urban areas can be adapted to protect or maintain lake quality. Zoning, for ex-
ample, was developed to minimize conflicts between potentially incompatible land
uses such as heavy industry^-commercial areas and residential homes in urban
areas. Zoning also can be used to protect lake quality. Setback zones or areas
typically are used to protect highway corridors. Setback regulations for piers,
boathouses, wharves, and homes can help preserve shore cover, vegetation, and
aesthetics. Some lake communities have a minimum setback of 75 to 100 feet for
all buildings, including homes. . . '
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A variety of zoning regulations are available for lake management and protec-
tion; some are listed in Table 9-1. Many of these procedures were summarized by
public Technology, Inc., in its report on land management (1977). ,
Some communities protect lakes with regulations and ordinances that require
best management practicesbest management practices (BMPs) for existing uses
and planned development of the lakeside community. In the State of Washington,
for example, the community of Mountlake terrace regulates construction to mini-
mize nonpoint source pollution. '
Planned development of the lake's watershed is an -effective means of mini-
mizing lake problems while(maintaining economic growth in the community. Sub-
division regulations including minimum lot sizes, minimum frontage requirements,
minimum floor area, height restrictions, and land use intensity ratings also are ap-
plicable for lakefront property or the community around a lake. Several develop-
ment approaches are listed in Table 9-2. Planned unit developments that are
clustered (Fig. 9-1) can be combined with special protection, critical, or environ-
mentally sensitive area designations to provide lots and homes for people in a
lake environment and setting while avoiding direct pollution of lakes and protect-
ing important environmental resources or unique aquatic habitats. Clustered
developments allow much greater flexibility in arranging lots and use more
economical and efficient small-scale water systems and waste treatment sys-
tems. . .»
Cluster development . .
Figure 9-1.—Clustering of lots or homes in the portion of the watershed best suited to
development reduces problems in the lake and maintains economic development in the water-
shed. The same number of lots can be developed using the cluster approach but water supply
and waste treatment can be more efficient and affective. (After Fulton et al. 1971.)
205
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Table 9-1.—A variety of zoning techniques
• TOPIC
DEFINITION
Zoning
The regulation of building types, densities, and uses permitted in dis-
tricts established by law.
Special Permits/ Administrative permits for uses that are generally compatible with a
Special Excep- particular use zone, but that are permitted only if certain specified stan-
tions/Conditional dards and conditions are met. ,
Use Permits
Variances Administrative permits for uses that are generally compatible with a
particular use zone, but that are permitted only if certain specified
standards and condition are met.
Floating Zones Use zones established in the text of a zoning ordinance, but not
mapped until a developer proposes and the legislative body adopts
such a zone for a particular site.
Conditional An arrangement whereby a jurisdiction extracts promises to limit the
Zoning ' future use of land, dedicate property, or meet any other conditions. The
arrangement is either stated in general terms in the zoning ordinance or
imposed on a case-by-case basis by the legislative or administrative
body, prior to considering a request for a rezoning.
Contract Zoning An arrangement whereby a jurisdiction agrees to rezone specified land
parcels subject to the landowner's execution of restrictive covenants or
other restrictions to dedicate property or meet other conditions stated in
the zoning ordinance or imposed by the legislative or admini-
strative body.
Cyclical Rezoning The periodic, concurrent consideration of all pending rezoning applica-
tions, generally as part of an ongoing rezoning program, focusing upon
one district at a time.
Comprehensive
Plan
Consistency
Requirement
'Zoning
Referendum
Provisions that require all zoning actions, and all other government
actions authorizing development, to be consistent with an indepen-
dently adopted comprehensive plan.
Ratification of legislatively approved land use changes by popular vote,
before such changes become law.
Prohibitory Zoning The exclusion of all multifamily, mobile, modular, industrialized, prefab-
ricated, or other "undesirable" housing types from an entire jurisdiction,
or from most of the jurisdiction.
Agricultural The establishment of "permanent" zones with large (that is multiacre)
Zoning/Large Lot minimum lot sizes and/or a prohibition against all nonagricultural devel-
Zoning/Open opment (with the exception of single-family residences and, possibly
Space Zoning selected.other uses).
Phased Zoning/ The division of an area into (1) temporary holding zones closed to most
Holding Zones/ nonagricultural uses and/or with large minimum lot sizes, and (2) ser-
Short-Term Ser- vice areas provided with urban services and open for development in
vice Area the near term (for example 5 years).
Performance An arrangement whereby all or selected uses are permitted in a dis-
Zoning/Perform- trict if they are in compliance with stated performance standards, that
ance Standards is, if they meet stated community and environmental criteria on pollu-
tion, hazards, public s'ervice demands, etc.
Flexible Zoning/ Freedom from minimum lot size, width, and yardage regulations,
Cluster Zoning/ enabling a developer to distribute dwelling units over individual lots in
Density Zoning any manner the developer desires, provided (usually) that the overall
density of the entire subdivision remains constant.
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Table 9-2.—A variety of development options
TOPIC
DEFINITION
Planned Unit A conditional use or floating zone regulated through specific design
' Development standards and performance criteria, rather than through the traditional
(PUD) lot-by-lot approach of conventional subdivision and zoning controls.
Subdivision Procedures for regulating the'divisioh of one parcel of land into two or
Regulations more parcels—usually including a site plan review, exactions, and the
application of aesthetic, bulk, and public facility design standards.
Minimum Lot Size The prohibition of development on lots below a minimum size.
Minimum Lot Size A limitation on the maximum number of dwelling units permitted on a lot.
Per Dwelling Lot based on the land area of that lot (usually applied to multifamily housing).
Minimum Lot Size A limitation on the maximum number of rooms (or bedrooms) permitted on
Per Room a lot, based on the land area of that lot (usually applied to multifamily
housing).
Setback, Front- • The prohibition of development on lots without minimum front, rear, or side
age, and Yard yards or below a minimum width. •
Regulations •
Minimum Floor
Area
The prohibition of development below a minimum building size.
Height Restriction The prohibition of development above a maximum height.
Floor Area Ratio The maximum square footage of total floor area permitted for each square
(FAR) foot of land area. •
Land Use Intensity Regulations that limit the maximum amount of permitted floor space and
Rating ' require a minimum amount of open space (excluding parking areas) and
recreation space, and a minimum number of parking spaces (total and
spaces reserved for residents only).
The withholding of development permission whenever adequate public
facilities and services, and defined by ordinance, are lacking, unless the
facilities and services are supplied by the developer. • .' ,
Adequate Public
Facilities
Ordinance
Perm it Allocation
System
The periodic allocation of a restricted (maximum) number of building per-
mits or other development permits first to individual districts within a juris-
diction and then to particular development proposals.
Facility Allocation The periodic allocation of existing capacity in public facilities, especially in
System sewer and water lines and arterial roads, to areas where development is
desired while avoiding areas where development is not desired. •
Development
Moratorium/
Interim Develop-
ment Controls -
Special Protec-
tion Districts/
Critical Areas/
Environmentally
Sensitive Areas
A temporary restriction of development through the denial of building
permits, rezonings, water and sewer connections, or other develop-
ment permits until planning is completed and permanent controls and
incentives are adopted, or until the capacity of critically overburdened
public facilities is expanded.
Areas of local, regional, or State-wide importance—critical environ-
mental areas (for example, wetlands, shorelands with steep slopes);
areas with high potential for natural disaster (for example, floodplains
and earthquake zones); and areas of social importance (for example,
historical, archaeological, and institutional districts)—protected by a
special development review and approval process, sometimes involv-
ing State-approved regulations.
207
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Permits and Ordinances
Public facilities ordinances and sanitary permits can help minimize problems with
septic systems or housing growth that exceeds the capacity of existing waste
treatment systems. Sanitary permits can be required prior to building any struc-
ture for human occupancy, to determine if sites are suited for septic systems. Or-
dinances can be developed to limit building growth to a pace within the treatment
system's capacity to adequately handle increased wasteloads. These ordinances
can also provide for the orderly and timely expansion of waste treatment facilities.
Both time and zoning can be used to reduce use conflicts by prohibiting cer-
tain uses during a specified time of day or in selected areas (Fig. 9-2). For ex-
ample, pleasure motorboating and waterskiing could be restricted 10 a.m. to 6
p.m., which would minimize conflicts with anglers.
Time Zoning
Water-Skiing
10a.m. to 6,p.m.
Figure 9-2.—Conflicts among multiple users can sometimes be avoided by restricting the
space In which the activities occur or the time of day for these activities. After Fulton, et al.
1971. -
208
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For space zoning, certain shore areas of the lake could be limited to particular
uses such as swimming or fishing, with powerboating and waterskiing restricted
to open water areas. A minimum distance and speed could be specified; for ex-
ample, a powerboat should be at least 100 feetaway from an anchored fishing
boat or moving at no more than 5 mph. Restrictions on motor sizes (no motors on
some lakes, only electric motors, or only motors less than 10 hp) are commonly
used on small lakes or lakes in pastoral settings.
All of these regulatory procedures can be combined to provide the most
suitable approach for a particular lake or specific set of lake uses. Regardless of
the regulations or restoration practices employed, however, it is critical that lake
management be an integrated program of watershed and lake management that
is tailored to the particular uses and priority problems of the lake user.
Lake Monitoring
Monitoring programs have been outlined in previous chapters! Lake monitoring is
discussed here to emphasize its importance.. It is easier and much more cost ef-
fective to treat problems as they develop rather than when they have reached a
crisis or nuisance level. Monitoring is the only approach for determining whether
protection and maintenance approaches are effective.
.- Lakes are dynamic systems that age through time. As the lake ages, the ef-
ficiency and effectiveness of 'various management techniques can change.
Monitoring programs .can record these changes and determine either that
management procedures should be altered to maintain the same lake uses or
that the lake no longer can support these uses. Investment precedes dividends;
investing in monitoring pays dividends by ensuring lake management techniques',
are providing effective protection or maintenance of the desired lake uses.
Chapter 8 provides guidance for establishing a monitoring program to obtain
the most important information possible based upon financial resources.
The Lake Watch
Lake protection and maintenance is a continuous process, an organized effort to
ensure the wisest use of the resource and to record what happens in that
resource and relate those developments intelligently to past records and future
potential. .. • • .
More than the process, lake protection and maintenance is also a respon-
,sibility. A responsibility that does not stop with hiring a lake manager or volunteer-
ing to participate in the monitoring program.,Every lake user must be aware of the
individual's, role in protecting the resource.
That role can be as minor as tossing a gum wrapper on the lake shore, as ir-
responsible as failing to keep a septic system operating properly, as dangerous
as exceeding the speed limit for boats. Multiplied by many such user actions, this
repudiation of individual responsibility can bring trouble to any lake.
But the opposite can also be true. Educated, caring users — each assuming
• responsibility for the lake — ensure that this resource will continue to meet their
expectations.
209
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sburg, MS. ' . - /
Chapters
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Environ. Prot. Agency, Corvallis, OR.
Edmondson, W. T. 1072. Nutrients and phytoplankton in Lake Washington. Pages 172-193 in G. E.
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U.S. Department of Agriculture.,1984. Water Conservation Checklist for the Home. EC553.-12m-4-84.
U.A.R.
U.S. Environmental Protection Agency. 1980a. Capsule Report: Lake Restoration in Cobbossee
Watersheds. EPA-625/2-80-027. Center Environ. Res. Inf. Off. Res. Dev., Cincinnati, OH.
—. 1980b. Design Manual. Onsite Wastewater Treatment and Disposal Systems. EPA 625/1-80-
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———. 1989. Report to Congress: Water Quality of the Nation's Lakes. EPA 440/5-89-003.
Washington, DC. . •' '
Welch, E.B. and M.D. Tomasek. 1980. The continuing dilution of Moses Lake, Washington. Pages
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U.S. Environ. Prot. Agency, Washington, DC.
Chapter 6
m
Allen, S.K., Jr. and R.J. Wattendorf. 1987. Triploid grass carp: status and management implications.
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Arnold, W.R. 1979. Fluridone, a new aquatic herbicide. J. Aquat. Plant Manage. 17:30-3.
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Baker, J. et al. 1990. Biological effects of changes in'.surface water acid-base chemistry. State-of-
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Baker, J.P. and C.L. Schofield. 1982. Aluminum toxicity to fish in acidic waters. Water Air Soil Pollut
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Barnard, W.D. 1978. Prediction and control of dredged material dispersion around dredging and open-
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Benndorf, T., H. Kneschke, K. Kossatz, and E. Penz. 1984. Manipulation of the pelagic food web by
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Bennett, G.W. 1970. Management of Lakes and Ponds. Van Nostrand Reinhold Co., New York.
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Cooke, G.D. 1980. Covering bottom sediments as a lake restoration technique. Water Resour. Bull.
16:921-6. - - . , -
iooke, G.D. and R.E. Carlson. 1986. Water quality management in a'drinking water reservoir. Lake
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213
-------
_ . 1989. Reservoir Management for Water Quality and THM Precursor Control. Am. Water
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Cooke G D. and R.H. Kennedy. 1981. Precipitation and Inactivation of Phosphorus as a Lake Res-
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_ . 1989 Water Quality Management for Reservoirs and Tailwaters. Report 1 . In-lake Reservoir
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1*0 *
Cooke G D R.T. Heath. R.H. Kennedy, and M.R. McComas. 1982. Change in lake trophic state and
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Cooke, G.D., E.B. Welch, S.A. Peterson, and P.R. Newroth. 1986.' Lake and Reservoir Restoration. •
, Butterworth Publ., Boston. .,,««,, ^
Engel, S. 1982. Evaluating sediment blankets and a screen for macrophyte control in lakes. Off. Inland
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restore a put-and-take trout fishery in a stream acidified by atmospheric deposition. N. Amer. J.
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Geiaer N S 1983 Winter drawdown for the control of Eurasian watermilfoil in an Oregon oxbow lake
(BlueLake. Multnomah County). Pages 193-7 in Lake Restoration Protection and Management.
Proc. 2nd Anna Conf. N. Am. Lake Manage. Soc., Vancouver, B.C. EPA-440/5-83-001 . U.S. En-
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Haag, K.H. 1986. Effective control of waterhyacinth using Neochetina and limited herbicide applica-
tion. J. Aquat. Plant Manage. 24: 70-5. ......
Hanson M.J. and H.G. Stefan. 1984. Side effects of 58 years of copper sulfate treatment of the Fair-
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Hoar. S.K. et al. 1 986. Agricultural herbicide use and risk of lymphoma and soft-tissue sarcoma. J. Am.
Med. Ass. 256: 1141-7. '
Hutto T.D. and B.M. Sabol. 1986. Application of HARVEST, mechanical simulation mode), as an
' operational aquatic macrophyte management decision tool. Lake Reserv. Manage. 2: 267-70.
Kortmann. R.W. 1 989. Aeration: technologies and sizing methods. Lake Line 9: 6-7, 1 8-1 9.
Leopold, A. 1933. Game Management. Scribner, New York. •
Llndmark. G.K. 1982. Acidified lakes: sediment treatment with sodium carbonate— a remedy?
Hydrobiologia. 92:537-547. •
_ _. 1 985. Sodium carbonate injected into sediment of acidified lakes: a case study of Lake Lilla
Galtsjon treated in 1980. Lake Reserv. Manage. 1:89-93.
Lorenzen. M.W. and A.W. Fast. 1 977. A Guide to Aeration/Circulation Techniques for Lake Manage-
ment.' EPA-600/3-77-004. U.S. Environ. Prot. Agency, Washington, DC.
Martyn R D R. L. Noble; P.W. Bettoli. and B.C.. Maggio. 1986. Mapping aquatic weeds with aerial
color infrared photography and evaluating their control by grass carp. J. Aquat. Plant Manage. 24:
* ' '
\ >
Mayhew. J.K. and ST. Runkel. 1962. The 'control of nuisance aquatic vegetation with black
polyethylene plastic. Proc. Iowa Acad. Sci. 69: 302-7.
McComas. S.R.. G. Boronow. D.,Shodean. and J. Schilling. 1986. Fisheries management. Lake
Reserv. Manage. 2: 447-50.
McCowen, M.C. et al. 1 979. Fluridone, a new herbicide for aquatic plant management. J. Aquat. nant
Nail LE^an'd J.D. Schardt. 1980. Large-scale operations management test using the white amyr at
Lake Conway. Fla. Aquatic Macrophytes. Pages 249-72 in Proo. 14th Annu. Meet. Aquat.- Plant
Control Res. Plann. Oper. Rev. Misc. Pap. A-BO-3. U.S. Army Corps Eng.. V.cksburg, MS.
Newroth, P.R. and R.J. Soar. 1986. Eurasian watermilfoil management using newly developed tech-
nologies. Lake Reserv. Manage. 2: 252-7. o.
Nichols, S.A. 1986. Community manipulation for macrophyte management. Lake Reserv. Manage. 2.
245-51 - ' ' •
Nicholson. S.A. 1981. Changes in submersed macrophytes in Chautauqua Lake, 1.937-75. Freshw.
Biol. 11:523-30. , _ . _ _.
Nurnberg, G.K. 1987. Hypolimnetic withdrawal as a lake restoration technique. J. Environ. Eng. Div.
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Nyberg. P. 1989. The status of liming activities in Sweden. Living Lakes News 4(1 ):4-7..
Nyberg. P. and E. Thornelof. 1988. Operational liming of surface waters in Sweden. Water A.r So.l Pol-
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Olam, H. 1 990. Liming Acidic Surface Waters. Lewis Publishers, Inc., Chelsea, Ml.
Pastorok. R.A., T.C. Ginn. and M.W. Lorenzen. 1981 . Evaluation of Aeration/Circulation as a Lake
Restoration Technique. EPA-600/3-81 -01 4. U.S. Environ. Prot. Agency. Washington, DC,
Pennwalt Corp. 1984. Submersed Aquatic Weeds and Algae Guide. Philadelphia. • •
Peterson, S.A. 1981. Sediment-Removal as a Lake Restoration Techn.que. EPA-600/3-81 -01 3. U.S.
Environ. Prot. Agency, Washington. DC. ' •*•
_ 1982a Dredging and nutrient inactivation as lake restoration techniques: a comparison, in
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214
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Ripl, W. 1976. Biochemical oxidation of polluted lake sediment with nitrate—a new lake restoration
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—. 1980. Lake restoration methods developed and used in Sweden. Pages 495-500 in Restora-
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440/5-81-010, U.S. Environ. Prot. Agency, Washington, DC. .
Rosseland.'B.O. and A. Hindar. 1988. Liming of lakes, rivers, and catchments in Norway. Water Air
' Soil Pollut. 41 ;165-88.
Sanders, D.R., Sr.,and E.A. Theriot. -1986. Large-scale operations management test (LSOMT) of in-
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Shapiro, J., V. LaMarra, and M. Lynch. 1975. Biomanipulation: An ecosystem approach to lake res-
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Shireman, J.V. 1982. Cost analysis of aquatic weed control: fish versus chemicals in a Florida lake.
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Shireman, J.V. et at. 1983. Ecological Impact of Integrated Chemical and Biological Aquatic Weed
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Shireman, J.V., M.V. Hoyer, M.J. Maceina, and D.E. Canfield, Jr. 1985. The water quality and fishery of
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Walker, W.W., Jr., C.E. Westerberg, D.J. Schuler, and J.A. Bode. 1989. Design and evaluation of
eutrophication control measures for the St. Paul water supply. Lake Reserv. Manage. 5(1): 71-83
Welch, E;B. and C.R. Patmont. 1980. Lake restoration by dilution: Moses Lake, Washington, Water
Res. 14:1317^25.
Westerdahl. H.E. and K.D. Getsinger, eds. 1988. Aquatic Plant Identification and Herbicide Use
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Van, N.D., R.E. Girard, and C.J. Lafrance. 1979. Survival of .Rainbow Trout, Salmo gairdneri, in Sub-
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Chapter 7
Blank; L.T. and A.J. Tarquin. 1983. Engineering Economy. McGraw Hill, New York.
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Chapters
Wedepohl, R.E. et al. 1990. Monitoring Lake and Reservoir Restoration. U.S. Environ. Prot. Agency,
Washington, DC.
Chapter 9
Born, S. and D. Yanggen. 1972. Understanding Lakes and Lake Problems. Pub!. G2411. University, of
Wisconsin-Extension, Madison.
Fulton; J.K, et al. 1971. Inland Lakes: Analysis and Action. Ext. Bull. 718. Coop. Ext. Serv. Michigan
State Univ., Ann Arbor. •
'ublic Technology, Inc. 1977. Land Management: a Technical Reporffof State and Local Govern-
ments. Washington, DC. . •
215
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Appendix A
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 encpuraged 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 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
LENGTH
Millimeter.
I Centimeter
Meter
Kilometer
WEIGHT
' Micrbgram
Milligram
Gram
Kilogram
VOLUME
Milliliter
Liter
Kiloter
• (cubic meter)
SYMBOL
mm
cm
m
km
M-9
- mg
g .
k9
mL
L
kL
. (m3!
= 0.001 m
= 0.01 m
-1.0m
= 1000m
= 0.000001 g
= 0.001 g
= 1.0g
= ioodg
= 0.001 L
= 1.0L
= 1000 L
I .
ENGLISH UNIT
inch
inch
yard
mile
(no reasonable
grain
ounce(avoir)
pound'
ounce
quart
cu. yard
CONVERSION FACTOR*
0.03937
0.3937
1:094 .
0.6214
,
equivalent)
0.015432
0.03527
2.205
•29.57
1.057
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
217
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Appendix B
GLOSSARY
Acid neutralizing capacity (ANC): the equivalent capacity of a solution to neutralize
strong acids. The components of ANC include weak bases (carbonate species,
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.
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
example, 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.
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 fertile
stratified lakes in the summer and under ice in late winter.
Autochthonous: Materials produced within a lake; .e.g., autochthonous organic
matter from plankton versus allochthorious organic matter from terrestrial
vegetation.
Bathymetric map: A map showing the bottom contours and depth of a lake; can be
used to calculate lake volume. ;
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 how applied almost uniformly to the animals associated with the
substrate.
Biochemical oxygen demand (BOD): The rate of oxygen consumption by organisms
during the decomposition (= respiration) of organic matter, expressed as grams
oxygen per cubic meter of water per hour. '
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.
219
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Chemical oxygen demand (COD): No.nbiolpgical uptake of molecular oxygen by
organic and inorganic compounds in water. .
Chlorophyll: A green pigment in algae and other green plants that is essential for the
conversion of sunlight, carbon dioxide, and water to sugar. Sugar is then converted
• to starch, proteins, fats, and other organic molecules.
Chlorophyll a: A type of chlorophyll present in all types of algae, sometimes in direct
proportion to the biomass of algae. .
Cluster development: Placement of housing and other buildings of a development in
groups to provide larger areas of open space.
Consumers: Animals that cannot produce their own food through photosynthesis and
must consume plants or animals for energy (see 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.
Density flows: A flow of water of one density (determined by temperature or salinity)
over or under water of another density (e.g., flow of cold river water under warm
reservoir surface water). .
Detritus: Nonliving dissolved and paniculate organic material from the metabolic
activities and deaths of terrestrial and aquatic organisms.
Drainage basin: Land area from which water flows into a stream or lake (see
watershed). . • , . '
Drainage lakes: Lakes having a defined surface inlet and outlet.
Ecology: Scientific study of relationships between organisms and their environment;
also defined as'the study of the structure and function of nature.
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.
Effluent: Liquid wastes from sewage treatment, septic systems, or industrial sources
that are released to a surface water.
Environment: Collectively, the surrounding conditions, influences, and living and inert
matter that affect a particular organism or biological community.
Epllimnlon: Uppermost, warmest, well-mixed layer of a lake during summertime
thermal stratification. The epilimnion extends from the surface to the thermocline.
Erosion: Breakdown and movement of land surface, which is often intensified by
human disturbances!.
Eutrophlc: From Greek for "well-nourished," describes a lake of high photosynthetic
activity and low transparency.
Eutrophication: The process of physical, chemical, and biological changes
associated with nutrient, organic matter, and silt enrichment and sedimentation of
a lake or reservoir. If the process is accelerated by man-made influences, it is
termed cultural eutrophication. .
Fall overturn: The autumn mixing, top to bottom, of lake water caused by cooling and
wind-derived energy.
220
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Fecal coliform test: Most common test for the presence of fecal material from
warm-blooded animals. Fecal conforms are measured because of convenience;
they .are not necessarily harmful but indicate the potential presence of other'
disease-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
volume, 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
herbivores, to planktivores, to the larger predators:
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. , . ..
Gr.oundwater: Water found beneaththe soil's surface; saturates the stratum at which
it is located; often.connected to lakes.
Hard water: Water with relatively high levels of dissolved minerals such as calcium,
iron, and magnesium.
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
transpiration). Runoff, surface water, grouridwater, and water infiltrated in soils are
all part of the hydrologic cycle.
Hypolimnion: Lower, cooler layer of a lake during summertime thermal stratification.
Influent: A tributary stream.
Internal nutrient cycling: Transformation of nutrients such as nitrogen or
phosphorus 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
manmade. ,
Lake district: Aspecial purpose unit of government with authority to manage a lake(s)
and with financial powers to raise funds through mill levy, user charge, special
assessment, bonding, and borrowing. May or may not have police power to inspect
.septic systems, regulate surface water use, or zone land.
Lake management: The practice of keeping lake quality in a state such that
attainable 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).
'Limnology: Scientific study of fresh water, especially the history, geology, biology,
physics, and chemistry of lakes. Also termed freshwater ecology.
221
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Littoral zone: That portion of a waterbody extending from, the shoreline lakeward to
the greatest depth occupied by rooted plants-
Loading: The total amount of .material (sediment, nutrients, oxygen-demanding
material) 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).
Macrolnvertebrates: 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
consume detritus and algae.
Macrophytes: Rooted and floating aquatic plants, commonly referred to as
waterweeds. These plants may flower and bear seed. 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'
covenants 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.
Margina^one: 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.
Metalimnion: Layer of rapid temperature and density change in a thermally stratified
lake. Resistance to mixing is high in the region.
Morphometry: Relating to a lake's physical structure (e.g., depth, shoreline length).
Nekton: Large aquatic, and marine organisms whose mobility is not determined by
water movement—for example, fish and amphibians.
Nominal group process: A process of soliciting concerns/issues/ideas from
members of a group and ranking the resulting list to ascertain group priorities.
Designed to neutralize dominant personalities.
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
constructed for phosphorus because of its tendency to control lake trophic state.
Nutrient cycling: The flow of nutrients from one component of an ecosystem to
another, as when macrophytes die and release nutrients that become available to
algae (organic to inorganic phase and return).
Oligotrophic: "Poorly nourishedv" from the Greek. Describes a lake of low plant
productivity and high transparency. x
Ooze: . Lake., bottom accumulation of inorganic sediments and the partially
decomposed 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 matter: Molecules manufactured by plants and animals and containing
linked carbon atoms and elements such as hydrogen, oxygen, nitrogen, sulfur, and
phosphorus. . .
*
222
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Pathogen: A microorganism capable of producing disease. They.are of great concern
to human health relative"to drinking water and swimming beaches..
Pelagic zone: This is 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. -
s . • " •••••..•
pH: A measure of the concentration of hydrogen ions of a substance, which ranges
from very acid (pH = 1) 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 can not survive at pH of 4.0 or lower.
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. . . .
Phytoplankton: Microscopic algae and microbes that float freely in open water of
lakes and oceans; -
: • • - \ - -. " . ,
Plankton: Planktonic algae float freely in the open water. Filamentous algae form long
threads and are often seen as mats on the surface in shallow areas of the lake.
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
milligrams of carbon per square meter per hour.
Producers: Green plants that manufacture their own food through photosynthesis.
Prof undal zone: Mass of lake water and-sedime.nt occurring on the lake bottom below
the depth of light penetration.
Reservoir: A manmade lake where water is collected and kept in quantity for a variety
of uses, including flood control, water supply, 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
water. • •
.Secchi depth: A measure of transparency of 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.
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).
Seepage lakes: Lakes.having either an inlet or outlet (but not both) and generally
obtaining their water from groundwater and rain or snow.
Soil retention capacity: The ability of a given soil type to adsorb substances such as
phosphorus, thus retarding their movement to the water.
Stratification: Layering of water caused by differences in water density. Thermal
stratification is typical of most deep lakes during summer. Chemical stratification
can also occur.
Swimmers 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.
223
-------
Thermal stratification: Lake stratification caused by temperature-created differences
in water density..
Thermocline: A horizontal piane'across a lake at the depth of the most rapid vertical
change in temperature and density in a stratified lake. See metalimnion.
Topographic map: A map showing the elevation of the landscape at contours of 2, 5,
10, or 20 feet. Can be used to delineate the watershed. .
Trophic state: The degree of eutrophication of a lake. Transparency, chlorophyll a
levels, phosphorus concentrations, amount of macrophytes, and quantity of
dissolved oxygen in the hypolimnion can be used to assess state.
Voluntary lake'property owners association: Organization of property owners in an
area around a lake that members join at their option.
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
characterize lakewater.
Water table: The upper surface of groundwater; below this point, the soil is saturated
with water.
Watershed: Atirainage 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.
Zooplankton: Microscopic animals that float freely in lake water, graze on detritus
particles, bacteria, and algae, and may be consumed by fish.
224
-------
Appendix C
POINT SOURCE
TECHNIQUES
Facultative Lagoons: Facultative lagoons are intermediate depth (3 to 8 feet) ponds 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. Oxygen in the surface
stabilization zone is provided by reaeration and photosynthesis. In general, the aerobic
surface layer serves to reduce odors while .providing treatment of soluble organic by-
products of the anaerobic processes operating at the bottom.
CRITERIA
1. Status
2. Applications
3; Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
Fully demonstrated and in moderate use especially
for treatment of relatively weak municipal wastewater
in areas where real estate costs are not a restricting
factor. ' .'
Used for treating raw, screened, or primary settled
domestic wastewaters. Most applicable whealand
costs are low and operation and maintenance costs
are to be minimized.
' • **
The service life is estimated to be 50 years. Little op-
.erator expertise is required. Overall, the.system is
highly reliable, ,
In very cold climates, facultative lagoons may experi-
ence reduced biological activity and treatment effi-
ciency. Ice formation can also hamper operations. In
overloading situations, odors can be a problem..
Settled solids may require cleaning out.and removal
once every 10 to 20 years.
Potential seepage of wastewater into groundwater
unless lagoon is lined. _ , '
225
-------
Appendix C: Point Source Techniques (cont.)
Overland Flow Treatment: -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 also by plant up-
take. An underdrainage system consisting of a network of drainage pipe buried below
the surface serves to recover the effluent, to control groundwater, or to minimize .tres-
pass of wastewater onto adjoining property by horizontal subsurface flow. Vegetation is
a vital part of the process and serves to extract nutrients, reduce erosion and maintain
soil permeability.
CRITERIA
1. Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning '
6. Treatment Side Effects
REMARKS
Has been widely and successfully used for more than
100years.
Can provide the following benefits: 1) an economic
return from the reuse of water and nutrients to pro-
duce marketable crops or forage; 2) water conserva-
tion when used for irrigating landscaped areas; 3) a
means of recovering renovated water for reuse or for
discharge; 4) a means of controlling groundwater.
Extremely reliable.
Process is limited by soil type and depth, topography,
underlying geology, climate, surface and ground-
water hydrology and quality, crop selection and land
availability. Graded land is essential; excessive
slope increases runoff and erosion. Climate affects
growing season and application ceases during peri-
ods of frozen soil conditions. Prolonged wet spells
limit application by Gulf states and the Pacific North-
west coastal region.
Minimal, when properly operated.
226
-------
Appendix C: Point Source Techniques (cont)
Oxidation Ditch: An oxidation ditch is an activated sludge biological treatment process.
Typical oxi'dation ditch treatment systems consist of a single or closed loop channel 4 to
6 ft. deep, with 45° sloping sidewalls. Some form of preliminary treatment such as
screening, comminution or grit removal normally precedes the process. After p'ret'reat-.
ment, the wastewater is aerated in the ditch using-mechanical aerators that are mounted
across the channel. The aerators provide mixing and circulation in the ditch, as well as
sufficient oxygen transfer. A high degree of nitrification may occur in the process without
special modification because of the long detention times and high solid retention times
(10 to 50 days). Secondary settling of the aeration ditch effluent is provided in a separate
clarifier. Ditch loops may be oval or circular in shape. "EH" and "horseshoe" configura-
tions have been constructed to maximize fand usage.
CRITERIA
1, Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
There are nearly 650 shallow oxidation ditch installa-
tions in the U.S. and Canada. Numerous shallow and
deep oxidation ditch systems are in operation in Eu-
rope. The overall process is fully demonstrated for
carbon removal, as a secondary treatment process.
Applicable in any situation where activated sludge
treatment is appropriate. The process cost of treat-
ment is generally less than other biological pro-
cesses in the range of wastewater flows between 0.1
and10Mgal/d.
The average reliability is good with adequate re-
moval of oxygen-demanding material and solids.
Oxidation ditches are relatively expensive and re-
quire skilled operators for good performance.
Requires weekly to monthly sludge removal.
Solid waste, odor, and air pollution impacts are simi-
lar to those encountered with standard activated
sludge processes.
, *jS^^
227
-------
Appendix C: Point Source Techniques (cont.)
Septic Tank: 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 house-
holds or establishments. The system consists of a buried tank where wastewater is col-
lected and scum, grease, and settleable solids are removed by gravity and a sub-
surface drainage system where wastewater percolates in.to the soil.
CRITERIA
1. Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
Most widely used method of on-site domestic waste
disposal (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.
Properly designed, constructed, and operated, sep-
tic tank systems are efficient and economical. Sys-
tem life may equal or exceed 20 years.
Dependent 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 dis-
tance to well or surface water.
The sludge and scum layers in tank must be removed
every 3 to 5 years.
Groundwater contamination when pollutants are not
effectively removed by the soil. Increasing nitrate in
groundwater. Soil clogging may result in surface
ponding with potential health problems^
Septic Tank Mound System: A septic tank and mound system is a method of on-site
treatment and disposal of domestic wastewater that can be used as.an alternative to the
conventional septic tank-soil absorption system. In areas where problem soil conditions .
preclude the use of subsurface trenches or seepage beds, mounds can be installed to
raise the absorption field aboveground, provide treatment, and distribute the wastewater
to the underlying soil over a wide area in a uniform manner. ,
CRITERIA
1. Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
Proven successful alternative for difficult soil condi-
tions. •
Alternative to septic tank-soil absorption system in
problem soil conditions. Increases amount of soil for
purification before effluent reaches groundwater.
Septic tank-mound systems are viable alternatives to
centralized treatment facilities. Dosing equipment
should be routinely maintained, and septic tanks
must be periodically pumped out for systems to oper-
ate effectively.
Requires more space and periodic maintenance than
conventional subsurface disposal system, along with
higher construction costs. Cannot be installed on
steep slopes.
Septage requires disposal every 3 to 5 years.
Visual impact particularly in suburban areas. Drain-
age patterns and land use flexibility may also be af-
fected.
228
-------
Appendix C: Point Source Techniques (cont.)
Septic Tank-Sand Filter: Surface discharge of septic tank effluent is a method of on-
site disposal of domestic wastewater that can be used as an alternative to the conven-
tional soil absorption system. Where permitted by c68e, surface discharge units can be
employed in areas where subsurface .disposal systems are not feasible. Sand filter
trenches are similar-to absorption trenches but contain an intermediate layer of sand as
filtering material and underdrains for carrying off the filtered sewage. Buried sand filters,
which required less area than trenches, also can be used.
CRITERIA
1. Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
Sand filtration has traditionally been employed to
treat septic tank effluent and has had success.
Surface discharge systems are alternative designs to
be used where site conditions, including geology, hy-
drology, and lot size, preclude the use of the soil as a
treatment and disposal medium. Operation by com-
munities, rather than homeowners, is normally re-
quired to be successful.
Sand filters perform well, unless overloaded. Peri-
odic inspection is required to obtain proper function-
ing o'fchlorination units.
These systems are more expensive than conven-
tional on-site systems. Filter surfaces and disinfec-
tion equipment require periodic maintenance. Buried
sandtieds are inaccessible. Power is required for
pumping and some disinfection units. State or Fed- :
eral discharge permits along with sampling and mon-
itoring are required. • • "
Sand with organic waste must be removed from in-
termittent and recirculating filter surfaces when clog-
ging occurs and.may be buried on-site or require off-
site disposal.
Treated effluents are discharged to surface waters.
Odors may emanate from open filters.
229
-------
Appendix C: Point Source Techniques (cont.)
Trickling Filter: The process consists of a fixed bed of rock media over which waste-
water is applied for aerobic biological treatment. Slimes form on the rocks and treat the
wastewater. The bed is dosed by a distributor system, and the treated wastewater is col-
lected by an underdrain system. Primary treatment is normally required to optimize trick-
ling filter performance. The low rate trickling filter media bed generally is circular in.plan,
with a depth of 5 to 10 feet. •
CRITERIA
1. Status
2. Applications
3. Reliability
4. Limitations
5. Cleaning
6. Treatment Side Effects
REMARKS
This process is highly dependable in moderate cli-
mates.
Treatment of domestic and compatible industrial
wastewaters amendable to aerobic biological treat-
ment in conjunction with suitable pretreatment.
Highly reliable under conditions of moderate climate.
Mechanical reliability high. Process operation re-
quires little skill.
Vulnerable to climate changes and low tempera-
tures, filter flies and odors are common, periods of in-
adequate moisture for slimes can be common. High
land and capital cost requirements.
Sludge is withdrawn from the secondary clarifier at a
rate of 3,000 to 4,000 gal/Mgal of wastewater, con-
taining 500 to 700 Ib dry solids.
Odor problems; high land requirement relative to
many alternative processes; and filterflie's.
230
-------
Appendix D
BEST MANAGEMENT
PRACTICES
Much of the material in this appendix was taken from EPA's Guide toNonpoint
Source Pollution Control, Published by the Office of Water in 1987.
Animal Waste Management: A practice where animal wastes are temporarily held in
waste storage structures until they.can be.utilized or safely disposed! Storage units can
be constructed of reinforced concrete or coated steel. Wastes are also stored in earthen
ponds. Also includes diverting runoff to pass barnyard areas, elimination of winter ma-
nure spreading, applying manure at P requirement rates, and not applying manure to
poorly drained areas. , '
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
e) Bacteria
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Not applicable.
Good to excellent.
Good to excellent. Reduction of P to surface waters
of 80 to 90 percent. ,
Not applicable.
Good to excellent. Reduction of bacteria to surface
waters by 80 to 90 percent. s
High because of the necessity of construction and
disposal equipment. Control of feedlot runoff costs
approximately $7500 yearly for every 50 animals.
Manure storage averages $2844 for each storage
facility.
Unknown.
Good.
Fair to excellent if properly managed.
Good.
The use of earthen ponds can possibly lead to
groundwater contamination.
Fertilizer management.
231
-------
Appendix D: Best Management Practices (cant)
Conservation Tillage: A farming practice that leaves stalks or stems and roots intact in
the field after harvest. Its purpose is to reduce water runoff and soil erosion compared to
conventional tillage where the topsoil is mixed and turned over by a plow. Conservation
tillage is an umbrella term that includes any farming practice that reduces the number of
•times the topsoil is mixed. Other terms that are used instead of conservation tillage-are
(1) minimum tillage where one or more operations that mixed the topsoil are eliminated
and (2) no-till where the topsoil is left essentially undisturbed.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff.
e) Pesticides
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good to excellent, decreases sediment input to
streams and lakes (60 to 98 percent reduced tillage,
80 to 98 percent no tillage). :,
Poor, no effect on nitrogen input to streams and
lakes.
Good to excellent, can reduce the amount of phos-
phorus input to streams and lakes (40to 90 percent
reduced tillage, 50 to 95 percent no tillage).
Fair to excellent, decreases amount of water running
off fields carrying sediment and phosphorus up to
about 61 percent.
Good; atrazine and alachlor losses reduced 80 to 90
percent.
High, because requires purchase of new equipment
by farmer.
Less expensive than conventional tillage. Potential
.increase in herbicide costs. Potential increase in net
farm income. As of 1984, the average cost per acre
was $31.
Good; approximately every five years the soil has to
be turned over.
Fair to excellent.
Good, but may be limited in northern areas that expe-
rience late cool springs, or in heavy, poorly drained
soils.-
Potential increase in herbicide effects and insecticide
contamination of surface and groundwater. Nitrogen
contamination of groundwater. On some soils, yields
are reduced. Phosphorus concentration in runoff
may increase.
Consider fertilizer management and integrated pesti-
. cide management.
232
-------
Appendix D: -Best Management Practices (cont.)
A
Contour Farming: A practice where the farmer plows across the slope of the land. This
practice is applicable on farmland with a 2-8 percent slope..
CRITERIA
1. Effectiveness
,. a) Sediment <
b) Nitrogen(N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good on moderate slopes (2 to 8 percent slopes), fair
on steep slopes (50 percent reduction). Reported
range in reduction of sediments is 15to 55 percent.
Unknown. •
Fair. .
Fair to good, depends on storm intensity.
No special effect.
No special effect.
Poor, it-must be practiced every time the field is
plowed.
Poor, not enough information.
Good, limited by soil; climate, and slope of land. May
not work with large farming equipment on steep
slopes.
Side effects not identified.
Fertilizer management, integrated pesticide man-
agement, possibly streamside management.
233
-------
Appendix D: Best Management Practices (corit.)
Contour Stripcropping: This practice is similar to contour farming where the farmer
plows across the slope of the land. The difference is that strips of close-growing crops or
meadow grasses are planted between strips of row crops like corn or soybeans.
Whereas contour farming can be used on 2-8 percent slopes, contour Stripcropping can
be used on 8-15 percent slopes. .
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs ,
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment .
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good, 8 to 15 percent slopes, provides the benefits of
contour plowing plus buffer strips. Reduces water -
erosion 40 to 60 percent and wind erosion 40 to 50
percent.
Unknown, assumed to be fair to good.
Unknown, assumed to be fair to good.
Good to excellent.
No special effect unless farmer cannot use the two
crops. Implementation costs average $24 per acre.
$3 to $5 per acre.
Poor, must be practiced year after year.,
Poor, not enough information.
Fair to good, may not work with large farming equip-
ment on steep slopes.
Side effects not identified. '
Fertilizer management, integrated pesticide man-
agement. • ' "*"
234.
-------
Appendix D: Best Management Practices (cont.)
*
Crop Rotation: Where a planned sequence of crops are planted int he same area of land.
For example, plow-based crops are followed by pasture corps such as grass or legumes
in two-to four-year rotations.
CRITERIA
REMARKS
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) RunofJ
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
Good when field is in grasses or legumes.
Fair to good.
Fair to good.
Good when field is in grasses or legumes.
High if farm economy reduced. Less of a problem
with livestock that can use plants as food.
Moderate, increased labor requirements. May be off-
set by lower nitrogen additions to the soil when corn
is planted after legumes, and reduction in pesticide •
application. ' , .
Good.
Fair to good.
Good, but some climatic restrictions. -
Reduction in possibility of groundwatercontamina- •
tion.
Range and pasture management.
235
-------
Appendix D: Best Management Practices (cant.)
Flood Storage (Runoff Detention/Retention): Detention facilities treat or filter out pol-
lutants or hold water until treated. Retention facilities provide no treatment. Examples of
detention/retention facilities include ponds, surface basins, underground tunnels, excess
sewer storage and underwater flexible or collapsible holding tanks.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability '
7. Potential Treatment
Side Effects
8. Concurrent Land
Use Practices
REMARKS
Fairto excellent/design dependent (56-95% effi-
cient).
Very poor to excellent, design dependent.
Very poor to excellent, design dependent.
Fairtoexcelteht, design dependent.
Dependent on type and size. Range from $100 to
$1,000 per acre served, depending on site. These
costs include capital costs and operational costs.
Annual cost per acre of urban area served has
ranged from $10 to $125 depending on site. '
Good to excellent, should last several years. '
Good, if properly designed.
Excellent.
Groundwater contamination with retention basins.
Porous pavements.
236
-------
Appendix D: Best Management Practices (com.)
Grassed Waterways: A practice where broad and shallow drainage channels (natural or
constructed) are planted with erosion-resistant grasses. .
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus
d) Runoff ,
e) Pesticides
2. Capital Costs
3. Operation and
. Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8, Concurrent Land
Management Practices
REMARKS
Good to excellent (60 to 80 percent reduction). '
Unknown. • ' , •
Poor to good; 5 to 40 percent.
Fair to good.
Poor to good, 5 to 40 percent reductions.
Moderate, about $22 per acre.
Low, but may interfere with the use of large equip-
ment. Average maintenance costs range from $1 to
$14 per acre per year.
Excellent.
Good.
Excellent. • ' .
None identified.
Conservative tillage, integrated pest management,
fertilizer management, animal waste management.
237
-------
Appendix D: Best Management Practices (cont)
Haul Roads and Skill Trails: This practice is implemented prior to logging operations. It
involves the appropriate site selection and design of haul road and skid trails. Hau.l roads
and skid trails should be located away from streams and lakes. Recommended guide-
lines for gradient, drainage, soil stabilization, and filter strips should be followed. .Routes
should be situated across slopes rather than up or down slopes. If the natural drainage
is disrupted, then artificial drainage should be provided. Logging operations should be
restricted during adverse weather periods. Other good practices include ground covers
(rock or grass), closing roads when not in use, closing roadways during wet periods, and
returning main haul roads to prelogging conditions when logging ceases.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence '
6. Adaptability
7. Potential Treatment
.Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good if grass cover is used on haul roads (45 percent
reduction); Excellent if crushed rock is used as
ground cover (92 percent reduction).
Unkriown.
Unknown. •
Unknown.
High, grass cover plus fertilizer $5.37/100 ft roadbed,
crushed rock (6 in) $179.01 /100 ft roadbed. Costs
may be offset by reducing road miles and decreased
construction maintenance costs.
f . , ,
High, particularly with grass that may have to be re-
plenished routinely and may not be effective on
highly traveled roads.
Unknown.
Good for ground cover, poor for nutrients.
Good.
Potential increase in nutrients to water course if ex-
cess fertilizers are applied.
Maintain natural waterways. ,
238
-------
Appendix D: Best Management Practices (cont.)
Integrated Pest Management: Pests are any organisms that are harmful to desired
plants, and they are controlled with chemical agents called-pesticides. Integrated pest
management considers factors such as how much pesticide is enough to control a prob-
lem, the best method of applying the pesticides, the appropriate time for application, and
the safe handling, storage, and disposal of pesticides and their containers. Other con-
siderations include using-resistant crop varieties, optimizing crop planting time, optimiz-
ing time of day of application, rotating crops, and biological controls.
CRITERIA
1. Effectiveness
, a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
e) Pesticides
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
No effect, but pesticides attached to soil particles can
be carried to streams and lakes.
No effect. .
No effect.
No effect, but water is the primary route for transport-
ing pesticides to lakes and streams.
Fair to good, 20 to 40 percent reductions.
No effect. •
Farming cost, potential reduction in pesticide costs
and an increase in net farm income.
Poor, as pesticides are applied one or more times per
year to address different pests and different crops.
Fair to excellent, reported pollutant reductions range
from 20-90 percent.
Methods are generally applicable wherever pesti-
cides are used: forest, farms, homes.
Potential for groundwater and surface water contam-
ination. Toxic components may be available to
aquatic plants and animals.
See crop rotation, conservation tillage. '
239
-------
Appendix D: Best Management Practices (cent.)
Interception or Diversion Practices: Designed to protect bottomland from hillside run-
off, divert water from areal sources of pollution such as barnyards, or to protect struc-
tures from runoff. Diversion structures are represented by any modification of the
surface that intercepts or diverts runoff so that the distance of flow to a channel system
is increased. " ,''.-' •.
CRITERIA
1. Effectiveness'
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Fair to good (30 to 60 percent reduction).
Fair to good (30 to 60 percent reduction).
Fairto good (30 to 60 percent reduction). , ' .
Poor, not designed to reduce runoff but divert runoff.
Moderate to high, may entail engineering design and
structures.
Fair to good.
Good.
Poorto good, largely unknown. -.
Excellent.
None identified. . ,
Since the technique can be applied under multiple
situations (i.e., agriculture, silviculture, construction),
appropriate best management practices associated
with individual situations should be applied. »
240
-------
Appendix D:, Best Management Practices (cont.)
Maintain Natural Waterways: rrhis practice disposes of treetops and slash in areas away
from waterways. Prevents the buildup of damming debris. Stream crossings are con-
structed to minimize impacts on flow characteristics.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
- d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Fair to good, prevents acceleration of bank and
channel erosion. %
Unknown, contribution would be from decaying de-
bris. • ,
Unknown, contribution would be from decaying de-
bris.
Fair to good, prevents deflections or constrictions of
stream water flow that may accelerate bank and
channel erosion.
Low, supervision required to ensure proper disposal
of debris.
Low, if proper supervision during logging is main-
tained, otherwise $160-S800 per 100 ft stream.
Good.
Good. ,
Excellent.
None identified.
Proper design and location of haul and skid trails;
streamside management zones.
241
-------
Appendix D: Best Management Practices (cant.)
Nonvegetative Soil Stabilization: Examples of temporary soil stabilizers include
mulches, nettings, chemical binders, crushed stone, and blankets or mats from textile
material. Permanent soil stabilizers include coarse rock, concrete, and asphalt. The pur-
pose of soil stabilizers is to reduce erosion from construction sites.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoffs
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Excellent. •
Poor.
Poor.
Poor on steep slopes with straw mulch, otherwise
good. '
Low to high, depending on technique applied. •
Moderate.
Generally a temporary solution until a more perma-
nent cover is developed. Excellent for permanent soil
stabilizer. . ...
Good.
Excellent.
No effect on soluble pollutants.
Runoff detention/retention.
m
242.
-------
Appendix D: - Best Management Practices (com.)
Porous Pavement: Porous pavement is asphalt without fine filling particles on a gravel
base. ' .'..."' '
CRITERIA
REMARKS
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c)'Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity •
5. Confidence
6. Adaptability .
7. Potential Treatments
Side Effects
8. Concurrent Land .
Management Practices
Fair to good, depends on pore size.
Fair to good, depends on pore size.
Fair to good, depends on pore size.
Good to excellent, depends on pore size.
Moderate, slightly more expensive than conventional
surfaces. May be high when old pavement must be
replaced.
Potentially expensive, requires regular street mainte-
nance program and can be destroyed in freezing cli-
mates.
Good, with regular maintenance (i.e., street clean-
ing), in southern climates. In cold climates, freezing
and expansion can destroy. .
Unknown.
Excellent.
Groundwater contamination from infiltration of solu-
ble pollutants. .
Runoff detention/retention.
243
-------
Appendix D: Best Management Practices (cont.)
Range and Pasture Management: the objective of range and pasture management is
to prevent overgrazing because of too many animals in a given area. Management prac-
tices include spreading water supplies, rotating animals between pastures, spreading
mineral and feed supplements, or allowing animals to graze only when a particular plant
food is growing'rapidly. •
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and '
Maintenance. Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good, prevents soil compaction, which reduces infil-
tration rates.
Unknown. •
Unknown.
Good, maintains some cover, which reduces runoff
rates. ' ,
Low, but may have to develop additional water
sources.
Low.
Excellent. •
Good to excellent. Farmer must have a knowledge of
stocking rates, vegetation types, and vegetative con-
ditions. •
Excellent.
None identified.
Livestock exclusion, riparian zone management, and
crop rotation. '
Riprap: A layer of loose rock or aggregate placed over a soil surf ace susceptible to erosion.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good, based on visual observations.
Unknown.
Unknown.
Poor.
Low to high, varies greatly.
Low. i
Good, with proper rock size.
Poor to good.
Excellent.
In streams, erosion may start in a new, unprotected
place. '
Streamside (lake) management zone.
244
-------
Appendix D: Best Management Practices (cont.)
Sediment Traps: Sediment traps are temporary structures-made of sandbags, straw
bales, or stone. Their purpose is to detain runoff for short periods of time so heavy sedi-
ment particles will drop out. Typically, they are applied within and at the periphery of dis-
turbed areas.
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices -
REMARKS
Good, coarse particles.
Poor. .
Poor.
Fair. •
Low. ' , '
Low, require occasional inspection and prompt main-
tenance. • . • . .
Poor to good.
Poor.
Excellent. . . • ' ••]
None identified.
Agricultural, silviculture or other construction best-
management practices could be incorporated de-
pending on situation.
245
-------
Appendix D: Best Management Practices (cont.)
Streamside Management Zones (buffer strips): Considerations in streamside man-
agement include maintaining the natural vegetation along a stream, limiting livestock ac-
cess to the stream, and, where vegetation has been removed, planting buffer strips.
Buffer strips are strips of plants (grass, trees, shrubs) between a stream and an area
being disturbed by man's activities that protects the stream from erosion and nutrient im-
pacts.
CRITERIA
1. Effectiveness
1) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence .
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good to excellent, reported to reduce sediment from
feedlots on 4 percent slope by 79 percent.
Good to excellent, reported to reduce nitrogen from
feedlots on 4 percent slope by 84 percent.
Good to excellent, reported to reduce phosphorus
from feedlots on 4 percent slope by 67 percent.
Gqod to excellent, reported to reduce runoff from
feedlots on 4 percent slope by 67 percent.
Good, moderate costs for fencing material to keep
out livestock and for seeds or plants.
Excellent, minimal upkeep.
Excellent, maintains itself indefinitely.
Fair, because of the lack of intensive scientific re-
search] '
May be used anywhere. Limitations on types of
plants that may be used between geographic areas.
Shading may alter the diversity and number of organ-
isms in the stream.
Conservation tillage, animal waste management,
livestock exclusion, fertilizer management, pesticide
management, ground cover maintenance, proper
construction, maintenance of haul roads and skid
trails.
246
-------
Appendix D: Best Management Practices (conf.)
.Street Cleaning: Streets and parking lots can be cleaned by sweeping, which removes
large dust and dirt particles, or by flushing, which removes finer particles. Sweeping ac-
tually removes Solids so pollutants do not reach receiving waters. Flushing just moves
the pollutants to the drainage system unless the drainage system is part of the sewer
system. When the drainage system is part of the sewer system, the pollutants will be
treated as wastes in the sewer treatment plant.
CRITERIA
1. Effectiveness
1) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Poor, not proven to be effective., •
Poor, not proven to be effective.
Poor, not proven to be effective. .
No effect. '. .
High, because it requires the purchase of equipment
by community.
Unknown but reasonable vehicular maintenance '
wpuld be expected.
Poor, have to sweep frequently throughout the year.
Poor.
To paved roads, might not be considered a worth-
while expenditure of funds in communities less than
10,000.
Unknown.
Detention/sedimentation basins.
247
-------
Appendix D: Best Management Practices (cont.)
Surface Roughening: On construction sites, the surface of the exposed soil can be
roughened with conventional construction equipment to decrease water runoff and slow
the downhill movement of water. Gropves are cut along the contour of a slope to spread
runoff horizontally and increase the water infiltration rate.
CRITERIA
1. Effectiveness,
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability -
7. Potential Treatment .
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Good.
Unknown.
Unknown.
Good.
Low, but require timing and coordination.
Low, temporary protective measure.
Short-term.
Unknown.
Excellent. ' , ,
None identified.
Nonvegetative soil stabilization.
Terraces: Terraces are used where contouring, contour strip cropping, or conservation
tillage do not offer sufficient soil protection. Used in .long slopes and slopes up to 12 per-
cent; terraces are small dams or a combination of small dams and ditches that reduce
the slope by breaking it into lesser or near horizontal slopes.
248
CRITERIA
1. Effectiveness
a) Sediment
b) Nitrogen (N)
c) Phosphorus (P)
d) Runoff
2. Capital Costs
3. Operation and
Maintenance Costs
4. Longevity
5. Confidence
6. Adaptability
7. Potential Treatment
Side Effects
8. Concurrent Land
Management Practices
REMARKS
Fair to good.
Unknown.
Unknown.
Fair, more effective in reducing erosion than total
runoff volume. .
High initial costs, an average of $73 per acre. '
Maintenance costs are $16 per acre annually but
may be offset by increased-income.
Good with proper maintenance. •
Good to excellent.
Fair, limited to long slopes and slopes up to 12 per-
cent.
If improperly designed or used with poor cultural and
management practices, they may increase soil ero-
sion. Subsurface nitrogen losses may increase.
Fertilizer and pesticide management. . ,-
-------
Appendix E
STATE AND
PROVINICIAL LAKE
MANAGEMENT
Appendix E represents perhaps the most dramatic change in this, the second
edition of the Manual. Its size alonerhas nearly doubled — from 22 programs in
the first edition to more than 50 in this volume. Forty-two States and eight
Provinces reported lake-oriented programs: at times, involving several agencies.
Ttyo major reasons account for this growth: increasing interest (and
knowledge) at the citizen level and, in the.United States, the nurturing by the
Federal Clean Lakes Program.
This Manual itself is evidence of the thrust of the Clean Lakes Program: EPA
is clearly committed to helping citizens take care of their own lakes. This
Manual provides the information necessary to that task; its supplements guide •
the technical manager in support of citizen efforts. And the Program's ongoing
support for Clean Lakes projects and their assessment provide the framework
that States can use to establish their own programs.
The citizens' own organization, the North American Lake Management
Society, works closely with the Clean Lakes Program in this technical transfer
effort, enabling citizens and scientists to share information essential to the wise
management of this continent's lake resources.
Updated by letters and phone calls just prior to publication, this appendix is
still incomplete. For example, several States and Provinces did not furnish
.information, but that doesn't necessarily mean they don't have some type of
lakes program. Please, if you can fill in some of those blanks — or add
to/correct/change existing information — contact the Clean Lakes Program,
Nonpoint Sources Branch (WH-583), U.S. Environmental Protection Agency,
401 M St. SW, Washington, DC 20460.
249
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United States
ALABAMA
Department of Environmental Management
Field Operations Division
1751 Cong. W.L. Dickinson Drive
Montgomery, AL36130
205/271-7935
Purpose To determine compliance with water use classification and as-
sociated water quality criteria.
Emphasis ' The department's lake program is primarily involved with water
quality assessment and prioritization of waterbodies for additional
diagnostic/feasibility studies. The majority of the State's lakes are
actually multi-use reservoirs created initially for electrical power
and/or navigation purposes. -
Program
Elements
1 Lake assessment: Major publicly accessible lakes are
monitored on a rotating basis, about 12-14 per year, during the
growing season to assist in documenting trophic status and
compliance with water use classification.
2. Federal Clean Lakes Program: Phase I Diagnostic/Feasibility
Study grants are used for appropriate lakes when available.
Assistance/ Technical cooperation and information are provided to States and
Services Federal agencies, the public, and others.
Funding
Sources
Staff .
Other Lake-
Related
Programs
U.S. EPA (majority funding source) and State legislature.
Lake assessments and diagnostic/feasibility studies are conducted
by departmental surface water monitoring staff and by contract. No
one staff member is dedicated full time to a lake program.
1 Alabama Nonpoint Source Program administered by the ADEM.
2. Reservoir Fisheries Management and Aquatic Plant Control
programs administered by the Alabama Department of
Conservation and Natural Resources, 64 N. Union Street,
Montgomery, AL 36130.
3 Others involved in lake management/monitoring activities
include the Tennessee Valley Authority, U.S. Army Corps of
Engineers, and the Alabama Power Company.
250
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ARIZONA
Department of Environment Quality
Water Assessment Section, 2655 E. Magnolia, Suite 2
Phoenix, AZ 85034
602/392-4006 '
Purpose To protect public health and to preserve, protect, and enhance the
environment of Arizona. ;-
Emphasis Current emphasis of the Arizona Clean Lakes program is to develop
and implement a program for expanded monitoring and assessment
of Arizona's lakes and to increase the level of protection, restoration,
and management of these water resources.
Program
Elements
1. Monitoring and assessment of lake water quality.
2. Environmental review and comment on land and water use
activities to address point and nonpoint source pollution
sources affecting lakes.
3. Promulgation of surface water quality standards.
4. Implementation of a nonpoint source pollution program
including watershed demonstration projects and development of
best management practices.
5. Administration of Phase I diagnostic/feasibility studies on
Roosevelt and Painted Rocks lakes.
6. Development of a riparian/wetlands habitat management
program.
Funding Base funding (65%) for the Arizona Clean Lakes program has been
Sources provided through Federal grants pursuant to Section 314 of the
Clean Water Act and the remainder by State match (35%).
Staff
Arizona Clean Lakes staff includes one permanent full-time
employee, two part-time State-service interns. Sixteen staff mem-
bers from the Water Quality Standards, Nonpoint Source, and Point
Source and Monitoring units also contribute support and assistance
to the Clean Lakes program (backgrounds in fisheries, aquatic biol-
ogy, engineering, hydrology, and agricultural sciences).
Interactions Public: Not listed .
Private: Not listed
Governmental: Federal — Army Corps of Engineers, Fish and
, Wildlife Service, Geological Survey, Bureau of Reclamation, Nation-
al Park Service, Forest Service, Bureau of Land Management
State: Dept. of Health Services, State Parks, Game and Fish
Department, Salt River Project
Academic: University of Arizona, Arizona State University
251
-------
ARKANSAS
Arkansas Department of Pollution Control and Ecology
8001 National Drive, P.O. Box 9583
Little Rock, AR 72209
'501/562-7444
Purpose Implementation of the provisions of the Clean Water Act and the
Arkansas Water and Air Pollution Control Act.
Program 1. Development and implementation of surface water quality
Elements standards.
2. Control of point source pollution through NPDES permitting
procedures.
3. Assessment of nonpoint source impacts for guidance in
implementation of best land management practices by
designated management agencies. .
4. Operation of statewide waterbody monitoring network.
Assistance Report available to the public: Water Quality Assessment of
Service Arkansas' Publicly Owned Lakes.
Funding ' Projects funded through Federal 314 grants and State legislative ap-
Sources propriations. Staff is federally funded through water quality program
grants.
Staff One part-time technical support staff person.
Other Lake-
Related
Programs
Statewide monitoring network periodically monitors water quality of,"
reservoirs.
252
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COLORADO
Colorado Department of Health
Water Quality Control Division
421OE. 11th Avenue
Denver, CO 80220
303/331-4578
Purpose
To protect the classified beneficial uses of lakes and reservoirs.
Emphasis Responsible for regulatory issues of eutrophication control by
managing point and nonpoint sources of nutrients in specific lakes.
Although there is no specific lake program, activities are conducted
as part of the whole water quality program.
Program
Elements
Assistance/
Service
1. Coordinate and manage the Federal Clean Lakes Program
Phase I and Phase II projects with council of governments, local
governments, and district or other organizations within the State.
2. Lake monitoring program funded through the Federal Lake
Water Quality Assessment Grant.
3. Water quality sampling and monitoring of pollutants in fish
tissue on specific lakes and reservoirs.
4. Other elements include wastewater discharge permits, water
quality standards, and general water quality management and
planning activities.
Technical guidance on request.
Funding
Sources
Combination of Federal and State.
Staff
For specific Jake activities, there are three staff with backgrounds in
aquatic biology, planning, and engineering who assist in the pro-
gram.
Interactions Variety of local, State, and Federal government agencies.
253
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CONNECTICUT
Department of Environmental Protection
Bureau of Water Management
Division of Planning and Standards, Lakes Management Section
165 Capitol Avenue, Hartford, CT 06106
203/566-2588 - .
i •
Purpose To develop and implement water quality management strategies and
policies that will deal with the problem of lake eutrophication, par-
ticularly excessive algae, aquatic plant growth, and dissolved
oxygen depletion.
Emphasis The program focuses on management of both statewide concerns
(nonpoint source management policy and construction grants pro-
gram) and individual lake projects. Grants are used as a key aspect
of management.
Program 1. Trophic status assessment: A study completed in the late
Elements 1970s is presently being updated. This study will analyze trends
in eutrophication and acidification.
2. Municipal/Industrial discharge management: evaluation of
lake water quality benefits attained after the implementation of
advanced wastewater treatment through State construction
grants. = '
3. Water quality standards: No discharges to Class A lakes.
Discharges to certain Class B lakes can't raise phosphorus
levels above 0.03 mg/L A lake trophic classification system is
" included.
4. Nonpoint source control: Development and distribution of a
guide to best management practices for controlling nonpoint
sources in lake watersheds.
5. Federal Clean Lakes Program: Administration of grants from
Section 314 Program for Phase I studies and Phase II
implementation projects.
6. Administration of cost-sharing grant program for diagnostic
feas-ibility studies and eutrophication abatement projects to
muni-cipalities and eligible lake associations for lakes with
public access.
7. Special projects: State appropriations have been made for
projects to (a) purchase a hydraulic dredge for lake
management projects and (b) develop individual lake
management projects.
Assistance/ Handbooks on best management practices for nonpoint source con-
Service trols, algae and weed control methods, and nuisance aquatic
vegetation control; cost-sharing grant programs to municipalities
and eligible lake associations for qualified lakes; and technical as-
sistance to towns, lake associations, and private pond owners.
Funding Individual projects, are funded through Federal 314 grants, State
Sources grant program, State legislative appropriations, and local sources.
Staff is federally and State funded.
254
-------
CONNECTICUT (continued)
Staff
One full-time and one part-time professional contribute to the pro-
gram. .
Interactions Public: Provide information to public:
Governmental: Grants/cost-sharing grant program to municipalities
and eligible lake associations for qualified lakes.
Other Lake- DEP, Pesticides Section, Hazardous Materials Management Unit;
Related DEP, Fisheries Bureau; DEP, Water Resources Unit, Department of
Programs Health Services. ,
255
-------
DELAWARE
Department of Natural Resources & Environmental Control
' > Division of Fish and Wildlife
89 Kings Highway, P.O. Box 1401
Dover, DE19903
302736-4590
Purpose Provide maximum fishing opportunity for freshwater anglers. •
Emphasis Applied research and management dealing, primarily with individual
problem lakes. Some problems (e.g., Hydrilla) deal with multiple
waterbodies.,
Program
Elements
Assistance/
Services
1. Fisheries management through (a) evaluation of fish
introductions, (b) investigation of largemouth bass regulation .
changes, (c) impact of advanced fingerling stocking, (d)
restoration of herring runs into freshwater impoundments, and
(e) evaluation of freshwater fishing by mail creel survey.
2. Investigation of vegetation removal in ponds by
(a) evaluation of partial aquatic vegetation removal,
' (b) evaluation of biological control including the use of triploid
grass carp, (c) Hydrilla investigations.
3. Evaluation of dredging on a freshwater community including
the impact of wetlands loss on a pond and sediment mapping of
public ponds.
Biologist available to assist owners on all ponds (private or public).
Funding Federal funds through the Dingell-Johnson Program and State
Sources funds through license receipts. ,
Staff •
Interactions
Other Lake-
Related
Programs
Six (primarily biology/ecology/fisheries background).
Public: Creel interviews and angler diaries. .
Private: None listed.
Governmental: Technical assistance to State/county .parks and
recreation departments and soil conservation services.
Soil Conservation Service: Technical aid to private owners; Univer-
sity of Delaware Extension Service; Delaware State College
Cooperative Fisheries Unit; Division of Water Resources, DNREC
— Clean Lakes Grant, contact Mark Blosser — Water Quality
Parameters; eutrophication land use controls for surface water
runoff.
256
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FLORIDA
Florida Department of Environmental Regulation
2600 Blair Stone Road
- Tallahassee, FL 32399-2400
904/488-0782
Purpose The program's purpose is to maintain and improve lake water quality
for the propagation of wildlife, fish, and other aquatic life, for public
recreational and other beneficial uses.
Emphasis The program focuses on providing monetary assistance to State,
county, and municipal agencies and water management districts for
: lake assessment and restoration activities.
Program 1. Clean Lakes Program: The Department administers the Clean
Elements Lake Program for the State of Florida.
2. Information Dissemination: Provide information on lake and
reservoir management and restoration.
3. Technical Assistance: Provide consultation and advice to
public organizations and citizens groups.
Assistance/
Services
Funding
Sources
Refer to program elements
Projects are federally funded through Section 314 Clean Water Act
and through various State programs such as the Surface Water Im-
provement and Management Program.
Staff
One program administrator and one program coordinator.
Interactions ' Public: Assist by providing information and participation on citizens
task forces,
Private: Disseminate information.
Governmental: Administrate U.S. EPA Clean Lakes Program.
257
-------
FLORIDA (continued)
Florida Game and Fresh Water Fish Commission
'. Lake Management Section
207 West Carroll Street
Kissimmee, FL34741
• 904/488-0782
Emphasis
Program
Elements
Assistance/
Services
Primarily management oriented; dealing with problem lakes or
watersheds. Discharge of sewage has been the major statewide
problem. Current emphasis shifting more toward controlling agricul-
tural runoff and surface water runoff from developed watersheds.
Primary emphasis offish and habitat management. Normally, grants
are not pursued but assistance is provided for local governments to
apply.
1. Development of lake restoration plans based on needs of
aquatic habitat, fisheries, arid wildlife and considering such
factors as water quality and quantity, lake level manipulation,
and aquatic plant management. v
2. Point and nonpoint source considerations.
3. Many plans have been developed using mechanical removal of
organic sediments, drawdown, or pumpdown along with
mechanical removal to restore aquatic habitat and associated
fish and wildlife values.
4. Cooperation with Federal, State, and local agencies and
elected officials to implement planned programs.
Develop or assist in development of restoration plans for public
lakes of greater than 5 acres. Also provide services by recommend-
ing management techniques to enhance fish and wildlife values.
Funding
Sources
Entirely from sale of fishing licenses.
Staff
Interactions
One Hmnologist; two fish management specialists; nine fisheries
biologists; two technicians; two secretaries (strong backgrounds in
lake drawdown, pollution control methodologies, and surface water
hydrology).
Public: Considerable, from phone calls to forrhalpublic hearings.
Private: Work with consultants during project planning and im-
plementation.
Governmental: Work with many other agencies during the planning
and implementation of projects.
SWIM Act: Passed by 1987 legislative action.
258
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GEORGIA
Georgia Department of Natural Resources
Environmental Protection Division
Water Protection Branch
/205 Butler Street, SW :
Atlanta, GA30334
404/636-4708
Purpose To protect and enhance the quality of Georgia's waters for their
. designated uses.
Emphasis Efforts primarily focus on water quality assessment and resolution of
problem issues. Lake programs are part of integrated approach to
, State waters that concentrates on assessing and maintaining water
quality standards.
Program 1. Lake classification: As part of a Clean Lakes Classification
Elements Grant, 175 lakes and reservoirs were evaluated in 1980-81.
Subsequent Clean Lakes funding in 1989 has been used to
further evaluate and classify 14 major reservoirs.
2. Lake monitoring: Ongoing Jake monitoring is conducted on
major reservoirs in the annual Major Lakes Monitoring Project
and on sites included in the Trend Monitoring Network.
3. Special studies and intensive surveys are conducted on
reservoirs on an as-needed basis to evaluate problem issues.
Federal Clean Lakes funds used for a portion of these studies.
Continued monitoring on lakes where EPD has required point
sources to reduce nutrient loading.
4. Comprehensive studies are beginning or planned for publicly
owned reservoirs greater than 1,000 acres. These studies will
be used to set nutrient and chlorophyll a standards in addition
.to current standards for dissolved oxygen, pH, and fecal
coliform bacteria.
Assistance/
Services
Coordination and management of Clean Lakes Program grants;
technical guidance on request; response to water quality concerns.
Funding
Sources
State appropriations and Federal grants.
Staff
Water Protection Branch monitoring
projects on an as-needed basis.
personnel are assigned
Other Lake-
Related
Programs
Game and Fish Division manages fisheries and aquatic plant
programs and responds to fish kill incidents.
259
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IDAHO
Idaho Division of Environmental Quality
1410 North Hilton
Boise, ID 83706
208/334-5860
Purpose The Division of Environmental Quality (DEQ) is responsible .for
protecting all ground and surface waters of the State. In the last
decade, Idaho has actively participated in the Federal Clean Lakes
Program and designed and implemented a citizen volunteer
monitoring program. A State lake protection program was estab-
lished in 1989 through passage of the Nutrient Management Act. A
second piece of legislation, the Clean Lakes Act, was also passed in
1989, establishing a pilot lake coordination program in the five
northern countries.
Emphasis The Nutrient Management Act focuses on two areas: completing a
statewide nutrient management plan emphasizing lakes and review-
ing locally developed plans for consistency with criteria set forth in
the act. Individual nutrient management plans are to be developed
' for each of the State's six hydrologic basins. These hydrologic basin
plans will be compiled into a State nutrient management plan by
January 1995.
The Clean Lakes Act authorized a pilot program in north Idaho and
formation of a council to coordinate all lake-related activities. The
council is empowered to conduct baseline studies, develop
management plans, conduct informational activities, and provide
technical assistance to lake associations. Existing resource agen-
cies and governments are relied upon for implementation and enfor-
cement.
Program The State Nutrient Management Act, North Idaho Pilot Program, and
Elements Federal Clean Lakes Program together include the following ele-
ments:
1. Prioritization of lakes for study.
2. Lake water quality assessment and management plan
completion.
3. Technical assistance to lake associations.
4.' Public involvement through advisory committee formation and
public meetings.
5. Public information and education.
6. Volunteer lake monitoring program.
Assistance/ DEQ and the Panhandle Health District work through the Clean
Services Lakes Council in north Idaho to provide technical assistance arid in-
formation and education support to local lake associations. Else-
where in the State, DEQ works with lake association, local units of
government, and private foundations to help solve lake water quality
problems. • '
260
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IDAHO (continued)
Funding A funding source to implement the plans developed under the
Sources Nutrient Management Clean Lakes Act was not established. Solving
lake water quality problems occurs primarily through other com-
plementary programs. The State municipal facilities grants and
loans program addresses sewage problems. The State Agricultural
Water Quality Program provides grants to farmers to install best
management practices. The Centennial Adopt-A-Stream pilot
project, funded under Cfean Water Act Section 319, provides small
grants for local water quality protection and restoration projects.
Other Section 319 demonstration projects address tributary
problems that affect lakes. The Federal Clean Lakes Program also
provides funding for implementing in-lake and watershed restoration
activities. •
Staff
Interactions
DEQ supports three staff with Federal project funds and one person
with State funds. The Panhandle Health District supports one per-
son with State funds to staff the Clean Lakes Council in north Idaho.
Public and private interaction is extensive through local lake as-
sociations, advisory committees, and public meetings. Governmen-
tal interactions are extensive through advisory committees and
cooperative projects.
261
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ILLINOIS
Illinois Environmental Protection Agency
Division of Water Pollution Control
Planning Section
2200 Churchill Road
Springfield, IL 62706
217/782-3362
Purpose To protect, enhance, and restore the quality and usability of lake
ecosystems.
Emphasis An integrated, multidisciplinary approach to lake use enhancement
•involving watershed protection and in-lake management to mitigate
past damage.
Program 1. Monitoring and lake classification to guide decislonmaklng:
Elements (a) Volunteer Lake Monitoring Program (VLMP): 260+ lakes
monitored for Secchi disk transparency, 50 for nutrients and
suspended solids, (b) Ambient Lake Monitoring Program
(ALMP): about 30 lakes/year monitored by division personnel.
2. Development and implementation of lake/watershed
management plans for public lakes under the Federal Clean
Lakes Program: Administration of the CLP-funded
protection/restoration projects. Currently, three projects
ongoing; two completed. J
3. Technical assistance and coordination to promote planning
and implementation initiatives funded by other sources:
• Interactions with other Federal, State, and local groups and
agencies.
Assistance/ Information and training for VLMP volunteers, other educational and
Services technology transfer information, development of lake/watershed im-
plementation plans.
Funding Federally funded through Sections 314,106, and 2050) of the Clean
Sources Water Acts. '
Staff
Four full time staff (Springfield HQ) plus regional office technicians
and aquatic biologists.
Interactions Public: Citizen volunteers (VLMP), Illinois Lake Management As-
sociation, Northeastern Illinois Planning Commission.
Private: Not listed.
Governmental: Federal — U.S. EPA, USDA.
State: Dept. of Agriculture, Dept. of Conservation, State Water Sur-
vey.
Development of an administrative framework plan as authorized by
the Illinois Lake Management Program Act (Nov. 1,1989). The plan,
if funded, would provide for an enhanced State Lakes Management
Program in Illinois.
262
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INDIANA
Indiana Department of Environmental Management
Office of Water Management
5500 West Bradbury AVenue
Indianapolis, IN 46241
317/243-5028 ^
Purpose
Protection and management of water quality in State lakes.
Emphasis A comprehensive, multidisciplinary program involving data acquisi-
tion, public education, and citizen involvement.
Program 1. Lake water quality assessment and classification to guide
Elements decisionmaking
2. Volunteer Monitoring Program — citizens monitor 100 public
lakes for Secchi transparency. • . •
3. Fish tissue and sediment toxics monitoring. .
4. Technical assistance to lake associations and local government.
Also assist local governments in applying for U.S. EPA Section
314 grants.
5. Public education: sponsor annual lake management
conference, publish quarterly newsletter, prepare lake
management guidance materials.
Assistance/ Technical assistance; training of volunteer monitors; prepare annual
Services fish consumption advisories; public education.
Funding State budget and Federal funds through Sections 205fl) 314 and
Sources 319 of the Clean Water Acts:
Staff
Three staff members implement the statewide fish tissue and sedi-
ment monitoring program. A portion of their time is spent on lakes.
Two additional staff members with biological background work part-
time on program coordination. The program is implemented by the
School of Public and Environmental Affairs of Indiana University
under contract with the Department of Environmental Management.
Interactions Public: Volunteer Monitoring Program; annual lake management
conference.
Private: Work with consultants involved in studies.
State government: Work with the Department of Natural Resources
to coordinate lake and,wetlands programs; with DNR and State
Board of Health on fish consumption advisories. '
Federal: U.S. EPA.
263
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INDIANA (continued)
Division of Soil Conservation
FLX1 Building, Purdue University
West Lafayette, IN 47907
. 317/243-5028
Purpose
Emphasis
Program
Elements
Assistance/-
Services
Funding
Sources
Staff
Interactions
Other Lake-
Related
Programs
To ensure the continued viability of Indiana's public access lakes.
Control of sediment and nutrient inflows from nonpbint sources.
Where appropriate, remedial actions may be taken to forestall or
reverse the impacts of such inflows.
Administration of the "T by 2000" Lake Enhancement Program, a
cost-share (grant) program to assist local entities in funding
feasibility studies and the design and construction of, sediment and
nutrient control measures.
Technical and financial assistance can be provided for qualifying
projects. .
State government funds and money raised locally by project spon-
sors.
Five individuals with solid conservation, engineering, and aquatic
biology backgrounds.
Public: Extensive inquiries for lake management information and
technical and financial assistance from individuals and local or-
ganizations.
Private: Deal with consultants on feasibility and design studies.
Governmental: Federal EPA, USDA Soil Conservation Service,
ASCS.
State: Indiana Department of Environmental Management (IDEM)
Indiana Department of Natural Resources (IDNR) — Divisions of
• Fish and Wildlife, Nature Preserves, Outdoor Recreation, Water.
Local: Soil and Water Conservation districts, park and recreation
boards, planning agencies, drainage boards.
IDEM: Indiana Clean Lakes Program, water quality regulations, non-
point source pollution programs permitting.
IDNR: Division of Water — permitting, lake level.
IDNR: Division of State Parks — limited sediment removal from
• lakes in State parks.
IDNR: Division of Fish and Wildlife — fisheries management in
public waters. .
264
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Iowa Department of Natural Resources
Fish and Wildlife Division
Wallace State Office Building, 900 East Grand
DesMoines, IA50319
515/281-8663
Purpose The lakes program is designed to protect and enhance the State's
valuable lake resources. The primary goal of the program is main-
' tenance of high quality lakes for swimming, fishing, and other
recreational uses.
Emphasis Program focuses on data acquisition, development, and implemen-
tation of lake watershed protection and lake restoration projects; im-
plementation of lake management plans, development, and im-
plementation of new management techniques; and public informa-
tion and education.
Program 1. Investigations and surveys of publicly owned lakes: monitor
Elements \ lake use and fjsh.populations, physical and chemical conditions,
and watershed use to detect changes that require management
strategies to be implemented; classification of lakes.
2. Research: conduct research that will provide new methods and
techniques to manage and protect Jake environments and
fisheries.
3. Lake protection/restoration projects: develop and implement
watershed protection/lake restoration projects, using Federal
Clean lakes Program or other Federal/State/local program
funds. •
4. Technical assistance: provide information to aid owners of
private impoundments manage their lakes and lake fisheries.
5. Fish stocking: stock number, size, and species of fish as
recommended in lake management plan.
6. Information dissemination: publish and distribute results of
research findings, technical lake management reports, and
information to the public and lake managers regarding fishing
opportunities, new lake management techniques, and lake
management plans.
Assistant/ Problem analyses, technical assistance, management plans, fish
Services stocking, dissemination of information materials, and develop-
merit/implementation of lake watershed protection and lake restora-
tion plans.
Funding Federal Aid (Dingell-Johnson);. Fish and Wildlife Trust Fund; Sec-
Sources tions205Q), 314, & 319 of Federal Clean Water Act.
Staff
Central office and field -staff of DNR Fisheries Bureau and other
DNR Divisions. - . -
265
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IOWA (continued)
Interactions
Other Lake-
Related
Programs
Public: extensive response to inquiries for information.
Prlvate:\consultation with lake protection associations.
Governmental: work closely with other DNR Divisions, U.S. Fish
and Wildlife Service, U.S. Environmental Protection Agency, County
Conservation Boards, and other local governmental agencies.
County Conservation Board lake programs; Iowa Water Resources
Research Institute — research into lake management problems;
DNR Stream Fisheries Research and Management Program; Iowa
Water Qualify Management Program; Iowa Nonpoint Pollution
Management Program; Iowa Publicly-owned Lakes Cost Share Pro-
gram; USDA- various ASCS and SCS Programs.
266
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KANSAS
Department of Health and Environment
Bureau of Environmental Quality
Forbes Field
Topeka,KS 66620
913/296-5575
Purpose To provide water quality information on lakes and address current
concerns of the public and the department.
• ' ' ' . I "
Emphasis Program stresses data acquisition and investigation to address in-
dividual lake problems and to assess generic problems such as
eutrophication or nonpoint sources. Response to public concerns is
a key focus of the program.
Program
Elements
1. Routine lake monitoring: 15-30 lakes/year.
2. Special investigations: Performed in-house or in cooperation
with other State, Federal, or local agencies, these studies
include: (a) the formation of trihaiomethanes in drinking water
supply reservoirs; (b) the occurrence and persistence of
pesticides in drinking water reservoirs; (c) the effects of
nonpoint source pollutants on lake water quality; and (d) the
causes and control of taste and odor problems reported by the
public or treatment plant operators.
Assistance/
Services
Funding
Sources
Special investigative surveys in response to public notifications of
observed lake problems.
The lake monitoring program is funded by the Federal and State
governments.
Staff
Four staff with -aquatic biology backgrounds assist,in the lake
monitoring program. Also, three to five part-time environmental tech-
nicians assist (20% time, total).
Interactions Public: Extensive response to public requests.
Private: Little to none.
Governmental: Grants for special studies.
Academic: Grants for special studies.
267
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KENTUCKY
Department of Environmental Protection
•• Division of Water
Fort Boone Plaza
18ReillyRoad
Frankfort, KY 40601
502/564-3410
Purpose To provide lake water quality data for making management
decisions on the use of point and nonpoint source controls to al-
leviate use impairments.
Emphasis Data acquisition.
Program 1. Ambient monitoring program: Six lakes are monitored for
Elements eutrophication trends on a revolving basis and three lakes for
long-term potential acid precipitation impacts.
2. Lake classification survey: A new survey of 99 lakes will be
completed in 1990 using Federal Clean Lakes Program funds.
This information is used to make decisions on new point source
discharges in lake watersheds and for 305(b) reporting
purposes.
3. Citizens participation program (Water Watch): Designed to
actively educate the public about water quality problems. One
' element ("adopt a lake" program) allows local groups to learn
about their lakes and watersheds.
4. Program staff review all NPDES permits for lake discharges
and recommend appropriate discharge limits, discharge
location, or denials based on trophic status and use support, or
potential use impairments.
Assistance/ Staff assistance in educating volunteer groups on lake sampling and
Service limnology; advice on private lake management problems.
Funding
Sources
Mainly Federal (Section 205j) funds.
Staff
Two part-time employees (aquatic biologists).
Interactions Public: Local volunteer groups through the monitoring/education
program. Response to inquiries on lake problems,
Private: Consulting firms, developers. ,
Governmental: Federal — Army Corps of Engineers, Soil Conser-
vation Service.
Interstate: Tennessee Valley Authority.
State: Department of Fish and Wildlife Resources.
Local: City officials.
268
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LOUISIANA
Department of Environmental Quality
Office of Water Resources
Natural Resources Building
P.O. Box 44091
Baton Rouge, LA 70804
504/342-6369
Purpose Responsible for protecting and preserving the quality of all surface
waters in the State. Lake water quality problems are handled within
the framework of the whole program; there is no separate lake pro-
gram. . •
Emphasis This water quality management and planning program is designed
to be flexible so that a variety of activities can be used to deal with
whatever problems arise. Grant aid has been used for both general
and specific lake investigations.
Program 1 / Monitoring: Establishment and implementation of monitoring
Elements- networks. >
j (
2. Water quality data assessment: On a case-by-case basis for
any waterbody. '
3. Wastewater discharge permits: Development, issuance, and
enforcement of permits for discharges to any waterbody.
4. Lake classification: An inventory of lakes and their trophic
indices was completed using Federal Clean Lakes Program
funds.
Assistance/
Services
Funding
Sources
Technical expertise and databases available. Field staff respond to
water quality complaints and fishkills.
Combination of Federal grants and self-generated fund from permit
fees and fines. ,
Staff
Interactions
About 100 members for all water quality issues.
Public: Attend public meetings on water quality issues.
Private: With consultants and private industry regarding the permit-
ting process. • ,
Governmental: Regulatory agreement with Louisiana Department
of Wildlife and Fisheries.
Other Lake- Louisiana Department of Agriculture: Nonpoint sources; Soil and
Related Water Conservation Commission: Nonpoint sources; Department of
Programs Transportation: Water sources and quantity^ Department of Health:
Wajter quality (coliforms); Department of Wildlife and Fisheries: Fish
resources; Soil and Conservation Service: Nonpoint sources, irriga-
tion; U.S. Geological Survey: Flow and hydrology
269
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Purpose
Program
Elements
Assistance/
Services
Funding
Sources
Staff
Department of Environmental Protection
State House #17 .
Augusta, ME 04333
207/289-390H
To direct long-term planning, protect lake water quality, and inform
and educate the public so as to maintain or improve the present
water quality of Maine's 5,000 lakes and ponds.
1. Vulnerable Lake Identification: Determining which lakes need
protection or restoration using vulnerability indices, value
indices, lake benthic indices, volunteer monitoring programs,
critical area program, and LURC wildlands lake assessment.
2. Priority List: Included on the' list are lakes (a) with declining
water quality; (b) sensitive for phosphorus loading; (c) in critical
areas; and (d) with cultural stress but stable water quality.
3. Protection Plans: Plans are formulated taking into account
water quality data from volunteer monitoring and diagnostic
studies, land use trends, lake associations (lobby), town
officials, local ordinances, soils information, subdivision
reviews, and conservation easements. Develop town
comprehensive plans.
4. Best Management Practices: Encouragement in the use of
BMPs at the State level through site and subdivision review,
and the Natural Resource Protection Act. DEP assistance is
provided for municipalities on development review, ordinances
and zoning, watershed districts, and town enforcement ro.les.
5. Development of a broad base of support through general
public and school education programs.
6 Lake Restoration: Problem lakes that deviate from their natural .
state are marked for efforts to control cultural activities.
7. Nonpoint Source Reduction: Efforts are aimed at agriculture,
forestry, and transportation.
8. other issues being studied include conflicting policies,
cumulative impact guidelines, scenic values, open space for
lakes, conflicting uses, and aquatic plant issues.
Technical guidance to municipalities, lake associations, and other,,
State agencies such as the Bureau of Land Quality.
•State funds,-Federal funds through Section 314.
Six biologists, One civil engineer, One environmental specialist, One
part-time support staff.
Interactions Public: Extensive response to public requests, watershed districts,
municipalities.
Governmental: Other State and Federal agencies; SCS/EPA.
University: Joint research with University of Maine.
270
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MASSACHUSETTS
Department of Environmental Protection
Division of Water Pollution Control
Lyman School, Westview Building
Westbordugh, MA01581
' 508/366-9181
Purpose To restore, preserve, and maintain publicly owned lakes and ponds
for recreation and enjoyment.
Emphasis The program focuses on providing monetary and technical assis-
tance to communities for lake restoration and on water quality data
acquisition.
Program 1. State Clean Lakes Program: Administration of a matching
Elements grant aid program to provide funds for diagnostic/feasibility
studies, long-term restoration/preservation projects, and
short-term in-lake maintenance projects.
2. Federal Clean Lakes Program: Administration of federally
funded CLP implementation projects.
3. Water quality monitoring: Limnological sampling to obtain
lake water quality data (a) to determine baseline lake
conditions; (b) to monitor post-implementation project changes;
and (c) to respond to public concerns about lake problems.
4. Aquatic Herbicide Application Licensing: Administration of
legislatively mandated license program for application of
chemicals in lakes.
Assistance/ Staff is funded by a combination of State and Federal money.
Services Matching grants were provided from State funds only or a combina-
tion of State and Federal funds. Currently, no new State funds are
available for the grant program.
Staff Three (backgrounds in aquatic biology, aquatic chemistry, and geol-
ogy).
Interactions Public: Extensive response to public requests for grants, surveys,
and information.
Private: Dealings with consultants and contractors working on
studies and implementation projects.
Governmental: Federal — Clean Lakes Program grants.
State: Cooperation with other DEP agencies, Division of Fisheries
and Wildlife, and Dept. of Environmental Management.
Local: Grant contracts with communities. ,
Other Lake- Division of Fisheries and Wildlife: Manages fisheries resources; lake
Related liming program; Department of Environmental Management:
Programs Manages lakes in State parks; DEP, Division of Water Supply:1 Water
supply reservoirs; DEP, Division of Wetlands: Wetlands Protection
Act. .
271
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Purpose
MICHIGAN
Department of Natural Resources
Land and Water Management Division
Inland Lake Management Unit
* BOX30028
Lansing, Ml 48909
517/373-8000
The Inland Lake Management Unit serves as a focal point and in-
formation source for lake and watershed management activities.
Emphasis Lake management through the administration of regulatory and
public assistance programs dealing with both specific lakes and
broad lake issues. •
Program 1. Aquatic nuisance control: Provide information to the public
Elements on nuisance aquatic macrophyte and algae control and on
swimmer's itch control (including oversight of a research
grant on swimmer's itch control). Responsible for issuing
permits.for herbicide use in surface waters.
2. Lake Improvement Boards: Serve as Department of
Natural Resources representatives on Lake Boards formed
to undertake lake restoration/management projects. Boards
have authority to tax riparian owners to fund projects.
Currently there are 75 active boards.
3. Federal Clean Lakes Program: Classification of all lakes
over 50 acres was completed in 1982. CLP grants have been
administered for two demonstration projects, four Phase I
studies, and two Phase II projects.
4. Inland Lake Self-help Monitoring Program: Established in
1974, the program involves volunteers in measuring Secchi
transparency. Until 1982 chlorophyll a was also measured.
5. Technical reviews: Staff are called on to review (a) NPDES
permit effluent limits for phosphorus discharges to lakes or
within 20 miles upstream of lakes; (b) recommendations on
the establishment of legal lake levels; and (c) dredge and fill
permits that might impact lake water quality.
6. Nonpoint source management: The ILMU provided input
(with the Surface Water Quality Division) to a recently
established State nonpoint source control incentives grant
program.
Assistance/ Public information bulletins and assistance, Self-help Monitoring
Services Program, technical assistance to other agencies.
Funding
Sources
Staff
Combined Federal (50%) and State (50%).
Four (backgrounds in limnology).
272
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MICHIGAN (continued)
interactions Public: Extensive inquires for information from public; work with
Self-help Program volunteers and Lake Boards.
Private: Deal with consultants on Lake Board feasibility studies.
Governmental; Federal — EPA Clean Lakes Program.
State: Coordinate with Dept. of Agriculture, Surface Water
Quality Div. (DNR), Engineering-Water Management Div. (DNR),
, Fisheries Div. (DNR), and other Div. of. Land Resource Programs
. , units (DNR).
Other Lake- Michigan Department of Agriculture: licensing of herbicides and
Related herbicide applicators; DNR, Surface Water Quality Division:
Programs NPDES permits and nonpoint source control; DNR, Land and
Water Management Division: Lake level control; DNR, Fisheries
Division: Fisheries management; DNR, Division of Land and
Water Management Division: Dredge and fill permits.
273
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MINNESOTA
Minnesota Pollution Control Agency
520 Lafayette Road
StPaul.MN 55155
612/296-7217
Purpose To preserve and protect Minnesota's lakes and to increase and
enhance their public use and enjoyment.
Emphasis The Minnesota Pollution Control Agency (MPCA) stresses protec-
tion and management through lake data collection, public educa-
tion, and interpretation, and the use of grants on specific lakes.
Program 1. Minnesota Clean Lakes Program: Since 1977 the MPCA
Elements has administered and supplemented the Federal Clean
Lakes Program. Because the MPCA feels that local
leadership, control, and coordination, play a key role in a
project's success, most projects are initiated at the local level
and the local project is responsible for implementing the
project and meeting the grant objectives. The MPCA
evaluates and prioritizes grant proposals before submitting
them to the U.S. EPA Region V office. To date, 48 lakes have
been involved in the program. " ,
2. Clean Water Partnership Program (CWP): The CWP is
Minnesota's nonpoint source program. This program
provides local units of government with resources to protect
and improve lakes, streams, and groundwater. A two-phase
process is used as in the Glean Lakes Program. Grants
were made available to 14 projects in February 1989.
3. Lake classification: About 1,400 of Minnesota's
approximately 12,000 lakes have been classified. .
4. Reference lakes: About 35 to 45 lakes are monitored
annually to characterize lake water quality in each of
Minnesota's ecoregions.
5. Citizen Lakes Monitoring Program: About 400 Lakes are
enrolled in this program. The MPCA initiated a program to
assist lake associations collect and interpret water quality
data.
6. Lake Assessment Program (LAP): LAP was initated in
1985 to assist lake associations collect and interpret water
quality data. Approximately 35 lake studies have been
completed through LAP.
7. Public education: MCPA staff routinely speak to interested
public groups about lake protection. The handbook "Citizens
Guide to Lake Protection" was drafted in conjunction with the
Gray Freshwater Biological Institute and is available for
distribution. The report "Trophic Status of Minnesota Lakes"
provides water quality data on over 1,000 lakes.
274
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MINNESOTA (continued)
Assistance/ Grants and grant administrative assistance are available on re-
Services quest. Technical expertise and educational materials are avail-
able to respond to public requests and complaints. Citizen Lakes
Monitoring Programs and Lake Assessment Programs are avail-
able.
Funding
Sources
Federal for staff and grants. State for grants.
Staff Six positions to administer the Clean Lakes Prbgram, Lake As-
sessment Program, Citizen Lake Monitoring Program, and refer-
ence lake monitoring.
Interactions Public: Extensive interaction with lake associations and other
public groups. .
Private: Consultants dealing with Clean Lakes Program.
Governmental: Federal —U.S. EPA, USDASCS.
State: DNR, Soil and Water Conservation Board.
Local: Municipalities and counties
Academic: University of Minnesota Limnological Research Cen-
ter, Freshwater Foundation, University of Minnesota Water
Resources Research Center. .
275
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MISSOURI
Department of Natural Resources
Division of Environmental Quality
Water Pollution Control Program
P.O. Box 176
Jefferson City, MO 65102
314/751-1300
Purpose To project the beneficial uses listed in the State water quality
standards.
Emphasis The program acts as a clearinghouse for lake monitoring and
management activities.
Program Limited review of monitoring and lake management activities of
Elements publicly owned lakes (50 acres).
» _ '
Funding There are no Federal or State funds specifically available for
Sources lakes.
Staff
One limnologist/aquatic biologist available.
276
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MONTANA
Montana Department of Health arid Environmental Sciences
Capitol Station
.; Helena, MT 59601
406/444-2406
Purpose
Management of both coldwater and warmwater fisheries.
Program 1. Routine stocking: Trout and salmon are stocked in
Elements coldwater lakes. Walleye, northern pike, and largemouth
bass are stocked in cool/warmwater lakes.
2. Reproducing populations: Considerable effort is being
given to establish reproducing sport fish populations in lakes
and reservoirs of all types, from high mountain lakes to
lowland lakes and from ranch ponds to large (200,000 acre)
reservoirs. -
Assistance/ Public education programs through written documentation and
Services through project WILD and education programs working with the
public school system. ,
Funding From State license dollars, and Federal government through
Sources Djngle/Johnson Programs.
Staff 108 staff members working in fisheries department, many of
whom are involved with lake management.
Interactions Public: None listed.
Private: Trout Unlimited, Walleye Unlimited, Montana .Wildlife
Federation, Montana Alliance Nature Conservancy.
Government: Federal — Army Corps of Engineers, Bureau of
Reclamation.
State: Department of Natural Resources.
Contacts Administrator, Fisheries Division (above address).
Department of Natural Resources.
Department of Agriculture.
277
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NEBRASKA
Nebraska Department of Environmental Control
Water Quality Division, Surface Water Section
301 Centennial Mall South, Lincoln, NE 68509-8922
402/471-4700
Purpose The mission of Nebraska's Clean Lakes Program is to protect,
enhance, and restore the quality and beneficial uses of lake
ecosystems.
Program 1. Physical, chemical, and biological monitoring to evaluate
Elements existing conditions and determine water quality trends.
2. Establish priorities through lake and watershed monitoring
and assessments.
3. Administration of lake and watershed projects.
4. Integrate Nonpoint Source and Clean Lakes programs.
5. Technology transfer and interaction with other Federal, State
and local agencies and groups.
Funding Federal funding through Section 314 of the Clean Water Act.
Sources Clean Lake Phase I grants have been awarded by EPA.
278
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NEBRASKA (continued)
Nebraska Game Parks Commission
Fisheries Division
2200 North 33rd Street
Lincoln, NE 68503
402/471-0641
Purpose To perpetuate and enhance the fish and wildlife resources of
Nebraska for recreational, aesthetic, educational, and scientific
use by Nebraskans and their visitors.
Emphasis The program involves management planning based on data col-
lection, analysis/and public input.
Program 1. Investigations and Surveys: Monitoring offish populations
Elements and habitats through standard survey techniques.
2. Management Planning: Development of lake management
plans designed to provide an optimum sustained yield.
3. Technical Assistance: Provide assistance to owners of
private waters in the proper management of their lakes and
ponds.
Assistance/ Technical assistance, management plans, published information-
Services al material. . . ,
Funding
Sources
Permittees, Federal aid (Sport Fish Restoration Act).
Staff
Division chief, administrative assistant, and 14 district fish
managers. -
Interactions Public: extensive response to inquiries for information.
Other Lake- Nebraska Game and Parks Commission, Fisheries Research
Related Section and Parks Division; Nebraska Department of Environ-
Programs mental Control; Nebraska Natural Resources District.
279
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NEW HAMPSHIRE
Water Supply and Pollution Central Commission
Biology Division
6 Hazen Drive, P.O. Box 95
Concord, NH 03301-6528
603/271-3503
Purpose To provide limnological services through planning, research, and
water quality monitoring to protect and restore the water quality of
the State's lakes and ponds in accordance with legislated uses.
Emphasis The program focuses on water quality protection through monitor-
ing efforts and public Information and technical assistance.
Program 1 Lake trophic surveys: Sampling of 40 to 50 lakes and
Elements ponds each year, winter and summer, for baseline, long-term
trends, and water quality compliance information.
2. Volunteer Lake Assessment Program: Use of citizen
volunteers to monitor the water quality of lakes and ponds
during the growing season for short- and long-term analysis.
3. Acid rain studies: Sampling of 20 low elevation lake outlets.
at spring and fall overturn) and about 30 high elevation
remote ponds (by helicopter) in spring for acid rain .
parameters to provide short- and long-term trend information
on acidic deposition impacts. Precipitation events are s
analyzed for pH, sulfate, and nitrate.
4. Federal Clean Lakes Program (Section 314): conduct
Phase I, II, and III studies to determine causes arid
recommend solutions for impaired lakes, to implement
restoration procedures, and. to monitor the effectiveness of
the restoration procedures.
5. New Hampshire Clean Lakes Program: Investigate and
control aquatic nuisances, manage exotic aquatic plants by
providing information material, eradicating small new
infestations, and granting matching funds to manage existing
infestations, and provide matching funds for the Section 314
program.
6. Special projects: Periodically, special lake projects are
conducted that don't fall into one of the above-listed
categories. Presently, lake sediment cores are being
analyzed for heavy metal content.
7. Public education/technical assistance: The lakes
program provides educational material and technical
assistance to towns, lake associations, schools, and thfe
general public.
Assistance/ Education material for the public (exotic weed control manual,
.Services answers to lake questions booklet, volunteer lake assessment
manual and newsletter, numerous technical bulletins on various
lake-related topics, and best management practices information);
280
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NEW HAMPSHIRE (continued)
lake water quality data, summaries, and reports;, presentations
and slide shows .to the public; lake education program for the
schools; lake development model for town planning boards; in-
vestigation for citizen complaints; microscopic identifications for
the public; matching funds for aquatic nuisance control and lake
restoration.
Funding State general funds and Federal Clean Lakes (Section 314)
Sources funds. .
Staff
Six State-funded and two federally funded limnologists/aquatic
biologists; one State-funded secretary; three to four seasonal
(State and Federal funds).
281
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NEW JERSEY
Department of Environmental Protection
Division of Water Resources
35 Arctic Parkway
Trenton, NJ 08638
609/292-0427 • . "
Emphasis
Program
Elements
Assistance/
Services
Funding
Services
Staff
Other Lake-
Related
Programs
The division uses a grant aid-oriented approach to deal with in-
dividual lake programs.
1. State Grants Aid: Funds provided for Phase I and II type
activities.
2. Federal Clean Lakes Program: The Division acts as official
applicant and administrator of Federal CLP funds when
available.
3. Herbicide application: Administration of State funds for
annual herbicide applications to State-owned lakes (about
$50,000/yr; about 12 lakes/yr).
Grant aid for studies, restoration, and herbiciding.
Federal CLP (when available) and State budget appropriations
for specific lakes.
One person with experience in lake issues..
New Jersey Division of Coastal Resources.
'
282
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NEW MEXICO
New Mexico Environmental Improvement Division
Surface Water Quality Bureau
Surveillance and Standards Section
1190 St. Francis Drive'
Santa Fe, NM 87503
505/827-2822
Purpose Monitor and assess the quality of publicly owned lakes and make
recommendations for best management practices for control of
nonpoint source pollution.
Emphasis The program's principal objective is to inventory and classify, ac-
cording to trophic status, the State's approximately 150 publicly
owned lakes and reservoirs. ~
Program
Elements
Assistance/
Services
Funding
Sources
The Clean Lakes program assesses and reports the physical,
chemical, and biological quality of New Mexico's public lakes and
reservoirs through intensive lake studies. The information is
reported in the biennial 305(b) Report to the U.S. Congress as re-
quired by the Clean Water Act; Section 305(b). The information
includes:' ,
1. Classification according to trophic status of the State's public
- . lakes.
2. Description of methods to control pollution of impaired lakes.
3. Description of methods to restore the quality of impaired
lakes.
4. Description of methods to mitigate effects of acid
precipitation in impacted lakes.
5. Listing of impaired lakes not meeting water quality standards.
6. Assessment of status and trends of water quality and
sources of pollution of impaired lakes not meeting water
quality standards.
Develop recommendations for water quality standards for State
Water Quality Control Commission and provide material and
analytic support for interactive agencies.
Federal funding through Section 314 of the Clean Water Act.
Staff Two full-time aquatic biologists.
Interactions Government: Federal — U.S. EPA, USDA-U.S. Forest Service,
U.S. Geological Survey, U.S. Army Corps of Engineers, U.S. Fish
and Wildlife Service, Bureau of Land Management, Bureau of
Reclamation, Soil Conservation Service.
State: Department of Game and Fish, Water Quality Control
Commission, Department of Agriculture, Energy, Minerals and
Natural Resources Department, State Universities.
283
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NEW YORK
Department of Environmental Conservation
Bureau of Technical Services and Research
50 Wolf Road
Albany, NY 12233 .
518/457-7470
Emphasis The program uses a wide variety of methods to address both
project-specific and statewide issues (such as acid precipitation
impacts). '
Program 1. Financial assistance: State appropriations (about $1.5
Elements million) and Federal funds ($100,000) are primarily used on
lake restoration measures, such as dredging and harvesting,
with lesser amounts spent on watershed work, monitoring,
and research.
2. Citizens Statewide Lake Assessment Program: The DEC
conducts this monitoring program using volunteers to aid '
general statewide efforts.
i
3. Restoration projects: The program conducts and monitors
restoration projects.
4. Fish hatcheries: The DEC operates hatcheries and
conducts a fish stocking program.
5. Public accesses: The Department strives to improve public
access through land acquisition for new sites and
development of existing facilities (fish piers, boat ramps, etc.).
6. Statewide surveys: Surveys conducted to monitor acid
' precipitation impacts-and general lake water quality.
Assistance/
Services
Financial and technical assistance.
Funding
Sources
Federal and State.
Staff
Six people in the Central Office (Albany) with backgrounds in en-
vironmental engineering or aquatic biology. Most of the nine
regional offices have a designated Regional Lake Manager.
Other Lake-
Related
Programs
Local and county health departments; county governments may
conduct restoration or water quality monitoring programs;
Federation of Lake Associations: public information and citizen
monitoring programs (273 Hollywood Ave., Rochester, NY
14618).
284
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NORTH CAROLINA
Department of Environment, Health, and Natural Resources
Division of Environmental Management
512 N. Salisbury Street, P.O. Box 27687
Raleigh, NC 27611 , '
' ' ' , 919/733-5083
Because lake management in North Carolina involves a number of programs in
various agencies, universities, and companies, the following summary focuses on
efforts by the Division of Environmental Management but includes other
programs.
Program 1. Lake classification: Surveying and trophic classification of
Elements lakes began in 1981 using Federal Clean Lakes Program
funds. The State continued monitoring, lakes after Federal
funds ran out. Algal Growth Potential tests conducted by
EPA's Ecological Support Branch (Athens, GA) aided in
determining limiting nutrients.
2. Intensive Water Quality Investigations: Major sampling
efforts are ongoing for several multipurpose reservoirs.
Evaluations focus on various management issues, including
eutrophication, impacts from point and nonpoint sources of
pollutants, and water supply suitability.
3.' Federal Clean Lakes Program: Funding has been received
for both Phase I and Phase II projects dealing with
sedimentation, hydrilla, and persistent mercury
contamination. • - • ' '
4; Algal Bloom Program: This program was initiated in 1984
to document suspected blooms with reliable algal taxonomy
and quantification. Results are used to identify overly
' enriched waterbodies that qualify for Nutrient Sensitive
Waters designation or merit special nutrient management
plans.
5. Aquatic Weeds Program: This program involves the
identification of aquatic plant problems and the initiation of
corrective measures. Hydrilla infestation is a major concern.
6. Lake Assessment Modeling: Efforts have focused on
nutrient loading, and permitting of wastewater discharges to
lakes and reservoirs and their tributaries.
7. Public participation: Although no program currently exists
targeting lake management, the'Stream Watch Program
(coordinated by the Division of Water Resources) involves
some groups with lake management interests. The program
, provides a network of public education and participation in
environmental programs for groups such as schools,
community and fish clubs, Sierra and Audubon chapters, and
river basin associations. .
• Assistance/
Services
Technical assistance, educational materials.
285
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Funding
Sources
Staff
NORTH CAROLINA (continued)
Federal EPA and State legislature.
Five to six people in the Division of Environmental Management
participate in lake monitoring and assessment efforts. Lake
monitoring, data evaluations, modelling, and management plan
development are coordinated by Steve Tedder, Water Quality
Section Chief (919/733-5083)
286
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NORTH DAKOTA
Department of Health
Division of Water Supply & Pollution Control
1200 M issouri Avenue, Box 5520
Bismark, ND 58505-5520.
701/224-2354
Purpose To restore lakes for beneficial uses through the Federal program.
Emphasis The program deals with projects on natural and manmade lakes
with public recreational facilities.
Program Under the Lake Restoration Program grants are provided for
Elements projects designed to reduce lake eutrophication through water-
shed and/or in-lake treatments.
1. Provide technical help to local governments to aid in
restoration (Lake Improvement Associations).
2. Ambient water quality monitoring special projects, bioassays;
anything dealing with water quality standards.
3. Investigation of unusual aquatic phenomenan.
Assistance/ State grants of up to 25% of eligible project costs may be made
. Services when Federal funds are available.
Funding Currently the program has $150,000 available for 2 years.
Sources
Staff
Part-time, as needed.
Interactions State Fish and Game Department.
287
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NEVADA
Department of Conservation and Natural Resources
Division of Environmental Protection
123 West Nye Lane
Carson City, NV 89710
702/687-4670
Emphasis The purpose of the program may at times be site-specific (water
quality model development) or for developing baseline limnologi-
cal data to aid in water quality management decisions.
Program
Elements
1. Routine lake monitoring: three to four lakes per year.
2. Special investigations: (a) effects on point and nonpoint
source nutrient loading; (b) experimental fertilization to
enhance fishery production; and (c) model development to
aid in wasteload allocation.
3. Provide technical support by participating in cooperative
studies and providing laboratory support to other State and
local agencies.
Funding Federally funded through Sections 314, 106, and 205fl) grants
Sources with partial funding from the State.
Staff Two staff devote part of their time to the program. One has ex-
tensive limnological experience.
Interactions Cooperation with municipalities and their consultants; interaction
with EPA, U.S. Fish and Wildlife Service, Bureau of Reclamation,
Corps of Engineers, U.S. Geological Survey, Nevada Department
of Wildlife, State Parks, and Tahoe Regional Planning Agency.
Other Lake-
Related
Programs
Nevada Department of Wildlife - Fisheries Management Agency.
288
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OHIO
Environmental Protection Agency
Division of Water Quality Monitoring & Assessment
1800 Water Mark Drive,
P.O. Box 1049
Columbus, OH 43266-0149
614/644-2131
Emphasis Efforts deal primarily with water quality assessment, U.S. EPA
Clean Lakes Program; lake/watershed management plans, Sec-
tion 305(b) water quality inventory report.
«'
Program 1. Lake monitoring/classification: From 1975-80 a
Elements cooperative program with the U.S. Geological Survey
sampled 85 public lakes. Additional lake monitoring during
1990-81 and 1989-90 as part of a U.S. EPA Clean Lakes
Program Assessment Grants.
' 2. Developed Ohio Lake Condition Index to classify use
impairment in public lakes for the Section 305 (b) report.
3. Received four U.S. EPA Clean Lakes Program Phase I
grants (Summit Lake, Winton Woods-West Fork Mill Creek '
Lake. Indian Lake, Sippo Lake). Submitted one Phase I,
•two Phase II, and one Phase III projects in 1990.
_. 4. Partially funded a four-county citizen volunteer Secchi
disk monitoring program (NEFCO planning agency).
Potential for the program to be expanded statewide.
5. Water Quality Standards: all public lakes and wetlands
classified as State Resource Waters for protection of aquatic
life and recreational use.
6. Nonpoint Source Assessment and Management Plan.
Targeted lakes potentially affected by nonpoint sources of
pollution for the Section 319 report. Cooperative efforts with
Federal, State, and local agencies to address nonpoint
watershed management plans throughout the State.
Assistance/ Cooperative projects to develop lake/watershed management
Services . plans. Citizen complaints and spills. U,S. EPA Clean Lakes Pro-
gram for public lakes.
Funding Minimum of State general funds. Federally under through Sec-,
Sources tions31>4, 319, 205Q) and 106.
Staff Several people from Central Office and District Offices.
Interactions Public: Citizen complaints, citizen volunteer monitoring program,
Ohio Lake Management Society, areawide planning agencies.
Government: U.S. EPA, U.S. Geological Survey, Soil Conserva-
tion Service, Cooperative Extension Service, Ohio Department of
Natural Resources, County Soil and'Water Conservation Dis-
tricts.
289
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OREGON
Department of Environmental Quality
Executive Building, 8.11 SW Sixth Avenue
Portland, OR 97204
503/229-5284
Emphasis
Program
Elements
Assistance/
Services
The State's program is fairly small and tailored toward the
Federal Clean Lakes Program, Projects are aimed at problems in
specific lakes.
Specific projects are managed according to the Federal Clean
Lakes Program guidelines. They seek solutions for long-term
control of weeds, nutrient inputs, and improving flow and water-
shed management.
Currently there are two projects. Devils Lake in Lincoln City has a
nuisance aquatic weed problem, and Sturgeon Lake in North
Portland has an excessive sedimentation problem.
Coordination and management of Federal Clean Lakes Program
grants; sampling and technical guidance to local communities.
Funding
Sources
Staff
Primarily Federal Clean Lakes Program funds.
One part-time (limnology/environmental assessment back-
ground).
290
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PENNSYLVANIA
Department of Environmental Resources
Bureau of Water Quality Management
P.O. Box 2063
Harrisburg,PA17120 "
717/787-9633
Purpose To provide for a consistent and effective statewide approach to
controlling nutrients (phosphorus) to impounded waters so as to
maintain an acceptable trophic level that will not adversely im-
pact on designated water uses.
Emphasis The program focuses on regulatory issues as they affect in-
dividual priority lakes. Some technical input and funding are
provided for broader issues (nonpoint source control and acid
deposition). .
Program 1. Regulation of phosphorus discharges to lakes, ponds,
Elements and Impoundments: The regulations provide a systematic
method for protecting lakes and impoundments that are
undergoing eutrophication. It relies on empirical lake models
to estimate phosphorus loadings and to determine the
.appropriate level of protection or water quality improvement,
considering both point and nonpoint sources.
2. Data acquisition: Conduct lake surveys to obtain data that
support the imposition of phosphorus controls on wastewater
discharges.
3. Federal Clean Lakes Program: Coordinate the CLP with
interested and qualified lake watershed management
districts or organizations within the State. '
Assistance/
Services
Technical guidance on request.
Funding
Source
Combination of Federal and State.
Staff
Eight (backgrounds in water pollution biology/ecology).
Other Lake-
Related
Programs
DER, Bureau of State Parks: Lake treatment program for State
park lakes.
291
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SOUTH CAROLINA
Department of Health and Environmental Control
Bureau of Water Pollution Control
2600 Bull Street /
Columbia, SC 29201.
803/734-5296
The Department (SCDHEC) has no particular agency or staff responsible solely
for lake management. Issues relating to lake quality and management are dealt
with as part of program areas that have a larger overall function.
Program 1. Water quality sampling: Extensive sampling is conducted
Elements on the major lakes and special intensive surveys are .
conducted to evaluate specific waterbodies.
2. Classification: All of the State's lakes are actually reservoirs
created for electrical power. They are classified for primary
recreation (highest freshwater category excluding trout
habitat), and management strategies are developed based
on that classification.
3. Other elements Involve wastewater discharge permits,
' water quality standards, and general water quality
management strategies.
4. Reservoir management: Management of the major
reservoirs is by the organization that holds the license for its
operation.
a. Duke Power Co. (P.O. Box 33189, Charlotte, NC 28242) L.
Jocassee, LKeowee, L. Wylie.L Greenwood, L. Wateree.
b. U.S. Army Corps of Engineers (P.O. Box 899, Savannah,
GA31402) Hartwell Reservoir, Strom Thurmond Reservoir,
Russell Reservoir.
c. S.C. Electric & Gas (Palmetto Center, 1420 Main St.,
Columbia, CS 29201) Lake Murray, Montecello Reservoir.
d. Public Service Authority (P.O. Box 398, Moncks Corner, SC
29461) .Lake Marion, Lake Moultrie.
e. Carolina Power and Light Company (P.O. Box 327 New Hill,
NC 27652).
t
Funding 314, (106 rent fund supported State dollars; two to one match,
Sources State to Federal)'.
Staff
Two working under 314 Clean Lakes grants but no position dedi-
cated to lakes.
Other Lake-
Related
Programs
Dept. of Wildlife & Marine Resources: Manages lake fisheries;
Water Resources Commission: Manages Lake Robinson's
aquatic plants.
292
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SOUTH DAKOTA
South Dakota Department of Water and Natural Resources
Division of Water Resources Management
Clean Lakes/Nonpoint Source Section
. Joe Foss Bldg. Room 425
523 East Capital
Pierre, SD 57505-3181
" 605/773-4907
Purpose The Clean Lakes Program is responsible for diagnostic/feasibility
studies and restoration activities on publicly owned lakes. The
Nonpoint Source Program is an inter-agency and inter-organiza-
tional program to control nonpoint sources of water pollution.
Emphasis Individual lake restoration activities and nonpoint source pollution
. control. Statewide lakes assessment activities. Lake protection.
Program 1. Conducts both State-funded and federally funded
Elements diagnostic/feasibility studies on publicly owned lakes'
watersheds.. . '
2. Development of restoration alternatives for impaired lakes
; and streams. •
3. Management of the operation of four State-owned dredges
for sediment removal on impaired lakes. ,
4. Nonpoint source pollution control on a statewide basis.
Assistance/ Technical assistance to local governments and associations to
Services . conduct studies and restoration activities. Information and
education program. Nonpoint source project development and
implementation.
Funding Federal funding through Sections 314, 319, and 2050) of the
Sources Clean Water Act. State funding through Consolidated Water
Facilities construction grants and general appropriations.
Staff
Seven full-time biologists, one civil engineer, one geologist, eight
seasonal employees, one summer intern, clerical personnel, and
regional personnel.
Interactions Local lake associations, citizens groups, Conservation Districts
U.S. EPA, USDA, U.S. Fish and Wildlife Service, Forest Service,
S.D. Game, Fish and Parks, S.D. Dept. of Agriculture.
293
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rTENNESSEE
Department of Health and Environment
Division of Water Pollution Control
150 9th Avenue, N.
Nashville, TN 37247-3420
615/781-6643
Emphasis
Program
Elements
The program is primarily focused at regulatory issues of water
quality management including numerous impoundments (i.e.,
statewide scope). Research efforts are toward program support
and enforcement. The State has no specific lake projects; how-
ever, lake water quality is addressed as a part of the whole
regulatory program.
1. Water quality regulation.
2. Implementation and enforcement of the Tennessee Water
Quality Control Act.
3. NPDES primacy for State and Federal facilities and coal
mining.
4. Certifyin'g.agency for the 404 process.
5. Permitting: Wetlands, non-coal mining, and habitat alteration.
Assistance/ Technical cooperation with other agencies.
Services
Funding Mainly State with some Federal appropriations.
Sources
Staff
About 100 (backgrounds in engineering, biology, and water
quality).
294
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UTAH
Department of Health
Division of Environmental Health
Bureau of Water Pollution Control
288 North 1460 West
P.O. Box 16690
Salt Lake City, UT 84116
801/538-6146
Purpose, To preserve, protect, and restore the water quality of Utah's lakes
to enhance and assure their public use and enjoyment.
Emphasis Provide technical assistance and guidance in development of
programs for evaluation, implementation, or management for
water quality.
Program i. Routine lake monitoring and assessment in support of 305b
Elements reporting.
2. Special lake and watershed evaluation investigations in
conjunction with other agencies.
3.. Implementation of Federal Clean Lakes program.
4. Provide technical assistance on local task force or water
quality management units.
5. Lake classification and inventory.
6. Public education.
Funding
Sources
Staff
Other Lake-
Related
Programs
State and Federal revenues for program element. Federal grants
with local match monies for project implementation.
One position fo administer program with additional support staff
to conduct monitoring activities.
Utah Division "of Wildlife Resources:
Tim Provan: Bureau of Reclamation: Jerry Miller; Utah Depart-
ment of Natural Resources
Paul Gillette; Local Water Quality Management Agencies; Local
Water Improvement Districts.
295
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UtAH (continued)
Department of Natural Resources
Division of Wildlife Resources
1596 West North Temple
Salt Lake City, UT 84116
801/538-4700
Emphasis The program focuses on solving individual lake problems, but
some work is done on problems of a broader scope (acidic
deposition). Some research is also done.
Program 1. Fisheries management: Aspects of this program deal with
Elements predator-prey relations; exploitation; trout strain evaluations;
recovery of native trout populations; recovery or development
of black bass populations; studies to determine trout stocking
rates, times, and sizes; chemical renovation; population
monitoring; and development of management plans.
2. Acid deposition: Management of 650 soft water lakes in the
High Uintas region that could be affected by acidic
deposition.
3. Trout research: Limited study of sterile and hybrid trout.
Funding Mainly funded from fishing license sales and Federal aid (Wallup-
Sources Breaux).
Staff About 27 full-time in fisheries management (backgrounds in
fisheries science). Most spend 2% of their time ion lake manage-
ment.
Other Lake-
Related
Programs
Utah Department of Health: Richard Denton; Bureau of Reclama-
tion: Jerry Miller; Utah State Cooperative Fisheries Unit: Tim
Modde; Utah State University: Wayne Wurtsbaugh.
296
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VERMONT
Department of Environmental Conservation
Water Quality Division
103 South Main Street
Waterbury.VJ 05676 '
802/244-5638
c.
Purpose The Lakes and Ponds Program is responsible for planning and
managing in the best public interest all activities dealing with
Vermont's lakes.
Emphasis The primary objective is to assure the maximum sensible recrea-
tional potential of lakes through sound water quality management
practices. ;
Program 1. Monitoring and surveillance: The department keeps
Elements abreast of existing lake water quality conditions and detects
changes in lake quality conditions through the following six
data collection programs.
a. Spring Phosphorus Program: Sampling once a year in
the spring to monitor a large number of lakes for trends in
total phosphorus to determine existing trophic status and
detect impending water quality problems.
b. Acid Deposition Program: This program collects chemi-
cal and biological data on lakes located in low alkalinity
(acid-sensitive) regions of the State to determine the ef-
fects of acid deposition.
Lay Monitoring Program: Equipment and training are
provided under this program so that local residents may
collect lake water quality data weekly during the summer.
Secchi transparency, chlorophyll a and-total phosphorus
(on Lake Champlain only) are collected. This program
provides the majority of the summer water quality data
presently available on Vermont lakes.
d. Aquatic Plan Survey Program: Detailed qualitative
aquatic plant surveys .are conducted on selected lakes
each summer. The surveys are used to provide baseline
data to document future changes in the extent and/or
species composition of aquatic plant communities in Ver-
mont lakes.
e. Milfoil Watcher's Program: Volunteers are trained to
identify Eurasian watermilfoil and to search for new infes-
tations in presently infested lakes. It is hoped that,
through this program, new infestations will be found early
enough to make eradication possible.
f. Cooperative Bacteriological Sampling Program:
Under this program, local volunteers sample a limited
number of lakes for near-shore fecal conform bacteria
levels during July or August. This program serves the
dual purpose of involving lake residents in the monitoring
of septic systems and ensuring that the high bacteriologi-
cal quality of Vermont's lakes is rnaintained.
297
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VERMONT (continued)
Assistance/
Services
2. Special studies: For various reasons a specific lake may be
chosen for detailed water quality study. Lake studies may
involve long-term extensive data collection or limited data
collection and sophisticated lake modelling techniques.
Studies have been funded through the Federal Clean Lakes
Program and/or State funds. Special studies may also be
initiated to address particular areas of statewide concern
(such as a toxics monitoring program) or to gather additional
data in certain areas (such as periphyton or user
perceptions).
3. Management/restoration activities: Lakes with water
quality problems may undergo either maintenance or
restoration activities. Maintenance activities are control
measures to manage aquatic nuisances on a yearly basis.
Restoration activities are aimed at eliminating causes of lake
problems to achieve long-term benefits. Maintenance efforts
currently underway include the Lake Champlain Aquatic
Nuisance Control Program (harvesting of water chestnut)
and the Aquatic Nuisance Cpntrol Program (nuisance control
in other lakes). Restoration projects have been dealt with
through the CLP (both studies and implementation) and the
U.S.. Soil Conservation Service (agricultural best
management practices).
4. Lake Protection Program: Lake protection is promoted
through (a) monitoring and surveillance (described above),
(b) educational activities (slide shows; brochures;
. newsletters; manuals and short workshops), and (c)
regulation.
The Management of Lakes and Ponds Statute (permitting of
encroachment into waters), the Phosphate Detergent Ban, the
Water Quality Standards, and the Land Use Control Law, as
well as a variety of department regulations, provide regulatory
protection mechanisms.
Technical and educational assistance; grant aid for restoration
'and maintenance projects.
Funding Federal funds are provided for grants through the EPA (Clean
Sources Lakes Program) and Army Corps of Engineers (Lake Champlain
Aquatic Nuisance Control). The State legislature provides other
funds.
Staff
Six full-time (backgrounds in limnology, biology/botany engineer-
ing, and environmental education), three part-time (statistics and
administration), four limited time, and six seasonal.
298
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VIRGINIA
Water Control Board
2111 Hamilton Street, P.O. Box 11143
Richmond, VA 23230-1143
804/367-6406
Emphasis The program centers on monitoring publicly owned lakes to
determine lake trophic status and accelerated eutrophication
problems. .
Program 1. State Lake Monitoring Program: 15 to 20 .publicly owned
Elements - lakes are tested each year for general water quality
parameters. Data are used to update trophic status
information that was originally obtained under an EPA Clean
Lakes Program classification grant.
2. Federal Clean Lakes Program: Three lakes (Big
Cherry-Phase. I; Chesdin, and Rivanna Reservoir receiving
Phase II funding.
3. Lay monitoring: The VWCB assists volunteer sampling .
efforts by identifying algalsamples.
Assistance/
Service's
Funding
Sources
Technical assistance on .sampling methods and algal identifica-
tion; educational materials.
Primarily Federal (106) with minor State appropriations.
Staff
One person oversees the Lake Monitoring Program, which is car-
ried out by one to two people in each of six regional offices. They
have biology, chemistry, and environmental analysis back-
grounds; another person administers the Clean Lakes Grant.
Other Lake-
Related
Programs
Occoquan Watershed Monitoring Laboratory: Water quality as-
sessment in the suburban Washington, D.C., area.
299
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WASHINGTON
Department of Ecology
Mail Stop PV-11
Olympia, WA 98504-8711
206/459-6062
Purpose The Department's lake restoration program endeavors to restore
to lakes those beneficial uses that have been lost or impaired in
the recent past (i.e., 50 years).
Emphasis The program is primarily grant-aid oriented toward individual
problem lakes with public access. Remedial and preventive
projects are eligible for grant assistance. Some amount of applied
research is accomplished indirectly from grant projects and some
of the developments of these projects can be applied to other
lakes with similar projects.
Program 1. Diagnostic/Feasibility Studies (Phase I): Develops a water
Elements • and nutrient budget, identifies water quality problems and
their causes, and recommends restoration alternatives. Cpst
estimates for the proposed Phase II project are developed
and an environmental assessment may be prepared.
2. Implementation Projects (Phase II): Implements the
findings and recommendations of Phase I.
Assistance/ .' Grants of up to 75% of eligible project costs to public entities;
Services technical assistance on limnological questions, study require-
ments, lake association organization, aquatic macrophyte control,
etc.
Funding
Sources
Primarily State funds matched by local resources.
Staff
One full-time and two part-time people.
Other Lake-
Related
Programs
Washington Department of Wildlife (600 N. Capitol Way, Olympia,
WA 98504):
300
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WEST VIRGINIA
West Virginia Division of Natural Resources
Water Resources Section
Planning Branch
1201 Greenbrier Street
Charleston, WV 25311
304/348-5902
Purpose To preserve, protect, and restore the physical, chemical, and
biological integrity of the State's publicly owned lakes.
Emphasis Mitigation of current impacts primarily through control of local
nonpoint source pollution (watershed management) and secon-
darily through in-lake restoration.
Program
Elements
1. Lake Water Quality Assessment: 70 "non-priority" lakes .
field monitored by summer interns for a variety of physical
and chemical parameters: 12 "priority" lakes targeted for
- intensive quarterly water quality monitoring by division
personnel.
2. Coordination with local government agencies to develop
lake and watershed management plans under the Federal
Clean Lakes Program (CLP): Administration of CLP projects.
Currently, one Phase I project ongoing and one with
preliminary approval.
3. Interactions with Federal, State, and local agencies to
generate interest and. participation in the Federal Clean
Lakes Program.
Assistance/ Technical assistance/training for CLP participants. Guidance for
Services preparation and submittal of grant applications as well as assis-
tance with project implementation.
Funding Federally funded through Section 314 of the Clean Water Act with
Sources appropriate matching funds from State and/or local sponsoring
agencies.
Staff
One full-time aquatic biologist (Charleston HQ) plus a part-time
field assistant. Temporary summer employees are hired as
needed.
Interactions Federal: U.S. EPA, U.S. Forest Service, U.S. Soil Conservation
Service.
State: Dept. of Agriculture, Dept. of Energy, Division of Wildlife
Resources, Soil Conservation Commission.
Local: Regional planning councils, county governments, city
governments.
301
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WISCONSIN
. Department of Natural Resources
P.O. Box 7921
Madison, Wl 53707-7921
' 608/267-7513
Purpose To protect and maintain Wisconsin's lake resources for our own
and future generations; to help carry out measures that protect and
maintain lakes; and to strive for active coordination between the
many government programs and personnel that work on lakes.
Emphasis . The program guides local lake management organizations across
the State in planning and carrying out a variety of lake protection
measures including soil and water conservation, lake user educa-
tion, and advocacy for local protective regulations.
Program 1. Outreach and technical assistance: Day-to-day guidance to
Elements lake property owners on how to identify needs, find and
interpret lake/watershed information, and evaluate
management alternatives. Each year local actions are
promoted on "key lakes" that need special protection.
2. Self-help monitoring: Volunteers are trained to measure
water clarity and lake levels. Each year the volunteers receive
an interpretation of their lake data and a statewide summary ,
report. Their data provide the DNR with long-term data on a
larger number of lakes than it could survey.
3. Education activities: In conjunction with the University of
• Wisconsin-Extension the DNR provides water quality
information to help lake property Owners. Assistance is '.
available through conventions, workshops, field days, and
publications (such as: "The Lake in Your Community"; "Lake
Tides," a newsletter; and "A Guide to Lake Management Law").
4. Trend monitoring: Fifty representative lakes across the State
are monitored for physical, chemical, biological, and watershed
changes. Analyses of these data are used as an evaluation
tool to compare lakes statewide and to provide policy
directions.
5. Research and demonstration projects: The intent of this
element is to develop, test, and demonstrate lake protection
and management techniques that can be used by local
organizations.
Technical guidance for public requests on lake problems. Training
in water quality monitoring for the self-help program. Educational
materials.
State.
Assistance/
Services
Funding
Sources
Staff
Other Lake-
Related
Programs
10 (six lake management coordinators in six DNR district offices;
four staff members in the Central Office with expertise in or-
ganization/planning, engineering, limnology, and hydrogeology).
None listed.
302
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WYOMING
Department of Environmental Quality
Water Quality Division •
Herschler Building/4th Floor W.
122 West 25th Street
Cheyenne, WY 82002
307/777-7098
Purpose Maintain or improve lake water quality in the State.
Emphasis Problem correction at the local level.
Assistance/ Technical assistance and guidance (staff-limited).
Services •
Funding Section 205(j) and 319 monies with required match. Will assist in
Sources obtaining Clean Lakes monies if requested.
Staff
Provided on ease-by-case basis as available. ,
ft
303
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Canadian Provinces
ALBERTA
Alberta Forestry, Lands and Wildlife
Fish & Wildlife Division
North Tower, Petroleum Plaza
9945-108 Street
Edmonton, AB T5K2G6
403/427-6180
Purpose The program is oriented toward the management and production
of fish populations in individual lakes.
Program 1. Lake habitat inventories: Surveys provide data on basic
Elements morphometry, water chemistry, and existing fish populations
to determine fish populations using regulations and fish
stocking programs.
2. Management of fish .populations using regulations and fish
stocking programs.
Assistance/ Providing information on lake characteristics, critical fish habitats,
Services fish populations, fish production and fisheries use to anglers, con-
sultants, and government agencies.
Funding Funds are mainly from the provincial government Part of angler
Sources license fees go to a habitat development program.
Staff
26 people (mainly fisheries background; some with wildlife
management experience).
Other Lake-
Related
Programs
Alberta Environment: Water resources management, water
quality control, environmental impact assessment; Alberta
Forestry, Lands and Wildlife-Land Division: Shorelands and ac-
cess; Forestry: Public access and recreation facilities (public
land); Wildlife: Fisheries and wildlife matters; Alberta Municipal
Affairs: Shoreland and access (non-public lands).
304
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MANITOBA
Department of Natural Resources
Fisheries Branch
1495 St. James Street, P.O. Box 40
Winnipeg, MB R3H OW9
204/945-7777
Emphasis
Program
Elements
The program is primarily management (regulation/rehabilitation)
oriented; dealing with both point (industrial pollutants and feedlot
runoff) and nonpoint source (agriculture and forest activities) pol-
lution. Some small grants are provided for aeration assistance
and experimental design of aeration techniques.
1. Summer and winter oxygen monitoring and aeration.
2. Riparian land use control.
3. Consultative role on environmental assessments of
developments causing point and nonpoint pollution.
4. Chemical rehabilitation of fish populations.
5. Recommendations on in-stream flows and take/reservoir
level strategies.
6. Controlling in-stream alteration (channelization) affecting
sediment loading.
7. Recommendations on reservoir shoreline stabilization
8. Fish screening at Outlet spillways. .
9. Rough fish removal.
Assistance/ Consultative services; grants and technical assistance for aera-
Services tion installations.
Funding
Sources
Provincial.
Staff
Nine fisheries biologists spend a portion (5-40%) of their time on
lake management issues.
Other Lake= Manitoba Environment, Workplace Safety and Health (139
Related Tuxedo Blvd., Winnipeg, MB R3N OH6).
Programs
305
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NEW BRUNSWICK
New Brunswick Department of Natural Resources & Energy
Fish and Wildlife Branch
P.O. Box 6000
Fredericton, NBE3B5H1
506/453-3755
m
Purpose
Emphasis
Program
Elements
Special Uses
Interactions
Staff
Funding
Sources
To assess, monitor, and manage fish populations and habitat of
publicly accessible lakes, impoundments, ponds and associated
streams for sustained quality sport fisheries use.
The ongoing program acquires data from initial and followup sur-
veys as the basis for planned fisheries regulatory, biological, or
habitat changes.
Inventory: Physical, chemical, biological, and angler or other
user characteristics are assessed.
Planning: Appropriate strategies are prescribed.
Management: Tailored plans to fit the situation are implemented
after appropriate public communications and review.
Public Information: Plans are made public at meetings and by
direct contact. Lake depth maps are made available on a limited
basis.
These data also are used in the habitat protection program of
which this department is one of the review agencies and the
major enforcement arm in terms of number of field officers avail-
able.
Extensive factual responses to public queries, concerns, and
complaints are made possible from this data bank. Other govern-
ment fisheries and environmental agencies also use these data.
One headquarters biologist and five .regional biologists are direct-
ly concerned with this program. All biological staff use the data.
Provincial government sport fish management funding.
Other Lake- New Brunswick Department of Environmental collects time series
Related of water quality data from certain lakes or impoundments.
Programs ' The Canada Department of Fisheries and Oceans has pH
monitoring programs established on 10 Southern New Brunswick
lakes considered sensitive to acid precipitation.
306
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NEWFOUNDLAND
Department of Environment
Water Resources Management
-'••'.. St. Johns, NF
709/772-4475
The department has expertise and policies dealing with problems regarding is-
sues such as water quality and water pollution. No other information available at
this time. Contact: WasiUllah, Director
Other Lake-
Related
Programs
Department of Fisheries & Oceans; Department of Environment
Canada
307
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NOVA SCOTIA
Department of Fisheries Division
P.O. Box 700
Pictou,NSBOK1HO
902/485-5056
Purpose As a result of the 1982 Federal-Provincial Agreement on Trout,
the Division has been provided with the responsibility for aug-
mentation and restoration of the recreational trout fishery.
Emphasis The Management Plan focuses on management and enhance-
ment of the recreational trout'fishery so as to provide maximum
benefit to trout anglers, present and future.
Program 1. Habitat: In cooperation with the Nova Scotia Department of
Elements Environment and the Federal Department of Fisheries and
Oceans fish habitats are assessed, monitored, and protected
through (a) close cooperation and review of internal activities
and programs with potential impacts on habitat, (b) active
• survey and assessment programs for better delineation of
usable habitat, (c) implementation of long-term habitat
improvement programs (stream clearing, stream stabilization
devices, erosion/sediment control, flowage stabilization
devices, etc.). ' , . '
2. Production: Hatchery production of trout fall fingerlings and
yearlings has been greatly accelerated at three departmental
. hatcheries. -
3. Research: to maximize the effectiveness of both artificial
and natural productions, research will be conducted in the
following areas.
a. Improved broodstock genetics (long-term survivorship,
disease resistance, fish quality, etc.).
b. Post-distribution impact assessments of hatchery stocked
fish on natural populations (disease susceptibility, genetic
pollution, behavior, long-term wild population dynamics,
etc.).
c. Effect of predator fish species on natural and stocked fish
populations and how to ameliorate predator imbalances
(chemical poisoning, habitat manipulation, stock
manipulation, angling, physical removal, etc.).
d. Identifying environmental limitations for natural recruit-
ment and stock introductions.
e. Developing criteria for the creation of specific angler op-
portunities.
f. Developing mechanisms and criteria for the enhancement
of sea-run fisheries to create better Province-wide
' fisheries opportunities, specifically inland waters with
identified natural'limitations.
308
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NOVA SCOTIA (continued)
4. Management: Development of a long-term Management
Plan to include (a) zonation of the Province based on
"environmental, stock, and user group consideration, (b)
regulatory management through joint initiatives of user
groups and the Department, (c) identification and
conservation of unique sustainable wild trout populations,
and (d) establishment of zone committees whose
responsibilities would include recommendation and '
assessment of special management initiatives.
.5. Enforcement: Work closely with enforcement agencies
(DFO and Dept. of Lands & Forests) to ensure that
management initiatives are monitored and enforced in each
zone.
6. Education: To ensure that the public is fully informed and
involved in the wise stewardship of its inland fisheries, the
Department will (a) prepare brochures, films, videos,
technical/scientific reports, etc., on fishery-related topics, (b)
ensure attendance at meetings to provide exchange of
information, and (c) involve public groups in enhancement
projects (construction of artificial reeds and streamside
incubators).
309
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ONTARIO
Ministry of Natural Resources
Fisheries Branch
Whitney Block, Queen's Park
Toronto, ON M7A1W3 .
416/965-7885
Program
Elements
Emphasis Most programs and projects are geared toward management, al-
though there are some research and assessment projects. Some
grant aid is available for public involvement programs. Individual
problem lakes are addressed as well as large numbers of lakes
where broader problems are perceived.
1. Fisheries management: Methods include habitat inventory,
habitat rehabilitation, habitat enhancement, and fisheries
research and assessment.
2. Water quality monitoring: Extensive water chemistry
surveys have been done on thousands of lakes and
integrated into databases. Numerous programs for lake
research and monitoring have developed from the acid rain
problem.
3. Self-help programs: The public can receive information and
assistance through local Ministry of Natural Resources
(MNR) and Ministry of Environment (MOE) offices. Typical
services include drinking water potability testing, septic tank
inspections, and fish management information.
4. Public participation: Programs developed toward public
participation include (a) the Community Fisheries
. involvement Program (CFIP) which stresses habitat
improvement and conservation of fish stocks and (b) the
MOE self-help program whereby cottagers measure Secchi
depth and chlorophyll a on a volunteer basis. .
Assistance/ Self-help and public participation programs; technical assistance;
Services educational information; grant aid for CFIP.
Funding
Sources
Other Lake-
Related
Programs
Regular Provincial budget funds.
Ministry of Environment, Acid Rain Program: Walter Chan
(416/323-5051); Ministry of Environment, Acid Precipitation Of-
fice, 7th Floor, 40 St. Clair Avenue W., Toronto, Ontario
M4V1M2); Federation of Ontario Cottagers Association (FOCA)
Jean Anthon (416/284-2305; FOCA, 215 Morrish Road #105,
Scarborough, Ontario M1C 1E9); MOE Public Information Centre,
135 St. Clair W., 1st Floor, 416/323-4321.
310
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QUEBEC
Ministere du Losir, de la Chasse et la Peche
Direction generale de la fauhe
150 est, boul. Saint-Cyriile
Quebec, QCG1R4V1
418/643-5405
Purpose The objectives of the Ministry of Leisure, Hunting, and Fishing
are resource conservation and optimization of social and
economic benefits of fish exploitation (native, sport, and commer-
cial).
Emphasis The program is oriented toward management of fisheries. In-
dividual lake problems are dealt with at the regional offices and
the central office (Quebec City) works on broader issues. A small
portion of the program deals with short-term (one to three years)
research on "applied" problems.
Program 1. Exploitation control zone
-------
SASKATCHEWAN
Purpose
Emphasis
Program
Elements
Saskatchewan Parks and Renewable Resources
Fisheries Branch
Box3003
Prince Albert, SKS6V6G1
306/953-2888
To maintain and enhance fish supplies, ensure an adequate
supply and variety of fish that will meet the needs of the major
user groups and maximize the contribution of the fisheries sector
to the provincial economy. •
The program focuses on fisheries management using a broad
issue approach (e.g., there are three management zones for
sport fish conservation measures). Regulations and activities can
be lake-specific.
1 Sport fish stocking: Stocking is used to maintain, enhance,
and diversify sport fisheries in the southern half of the •
Province. In the north, conservation measures are relied
upon to maintain fish populations.
2 Fisheries enhancement: Conservation and enhancement
measures are.used to maintain and rebuild fisheries. Fish
enhancement projects include rearing ponds, lake aeration,
fishways, and habitat improvement. Funds are available to
help conservation groups in these activities.
Assistance/
Services
Funding
Sources
Staff
Other Lake-
Related
Programs
Funds for fish enhancement; stocking.
Primarily government funded except the Fish Enhancement
Fund, which is from angling license fees.
42 permanent (mostly with background,in fisheries biology); 18
casual/part-time. •
Department of Environment: Environmental impact studies, pollu-
tion control, etc; Saskatchewan Water Corporation: Oversees all
aspects of water management; Resource Lands Branch (Sas-
katchewan Parks and Renewable Resources): Oversees mans
development around water (e.g., recreational subdivisions) and
on Crown land.
312
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Appendix F
«,
I
DOCUMENTS AND
FORMS
Editor's Note: These forms and documents are to be considered as ex-
amples ONLY! Any person or organization who is considering contracting
for services should have an attorney draft the proper contracts within a
given jurisdiction.
Safety
Safety and protection of workers, lake property owners and observers is paramount.
The following example of contract document is included to give the reader some
[background on what should be specified in contracts as well as citations to work
hours and safety standards. Individual contracts will have to be developed locally by
the sponsoring agency, local government offices and property owners with exact
work specifications written out to insure compliance and orderly progression of the
implementation of the lake restoration project. The following example was taken from
a lake restoration project in the State of Washington.
• PROTECTION OF WORK, PROPERTY, AND .PERSONS. The CONTRACTOR will be
responsible for initiating, maintaining and supervising all safety precautions and programs
in connection with the WORK and all materials or equipment to be incorporated therein,
whether in storage on or off the site, and other property at the site or adjacent thereto, in-
cluding trees, shrubs, lawns, walks, pavements, roadways, structures and utilities not
designated for removal, relocation or replacement in the course of construction.
The CONTRACTOR will comply with all applicable laws, ordinances, rules, regulations,
and orders of any public body having jurisdiction. He will erect and maintain, required by
the conditions and progress of the WORK, all necessary safeguards for safety and protec-
tion. He will notify owners of adjacent utilities when prosecution of the WORK may affect
them. The CONTRACTOR will remedy all damage, injury or loss to any property caused
directly or indirectly, in whole or in part, by the CONTRACTOR, any SUBCONTRACTOR
or anyone directly or indirectly employed by any of them or anyone for whose acts any of
them be liable, except damage or loss attributable to the fault of the CONTRACT DOCU-
MENTS or to the acts or omissions of the OWNER or the ENGINEER or anyone employed
by either of them or anyone for whose acts either of them may be liable, and not at-
tributable, directly or indirectly, in whole or in part, to the fault or negligence of the CON-
TRACTOR.
In emergencies affecting the safety of persons or the WORK or property at the site or
Idjacent thereto, the CONTRACTOR, without special instruction or authorization from the
ENGINEER or OWNER, shall act to prevent threatened damage, injury or loss. He will
313
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give the ENGINEER prompt WRITTEN NOTICE of any significant changes in the WORK
or deviations from the CONTRACT DOCUMENTS caused thereby, and a CHANGE
ORDER shall thereupon be issued covering the'changes and deviations involved.
• SUPERVISION BY CONTRACTOR. The CONTRACTOR will supervise and direct the
WORK He will be solely responsible for the means, methods, techniques, sequences and
procedures of construction. The CONTRACTOR will employ and maintain on the. WORK a
qualified supervisor or superintendent who shall have been designated in writing by the
CONTRACTOR as the CONTRACTOR'S representative at the site. The supervisor shall
have full authority to act on behalf of the CONTRACTOR and all communications given to
the supervisor sSall be as binding as if given to the CONTRACTOR. The supervisor shall
be present on the site at all times as required to perform adequate supervision and coor-
dination of the WORK.
• CHANGES IN THE WORK. The OWNER may at any time, as the need arises, order
chanaes within the scope of the WORK without invalidating the Agreement. If such chan-
gesTncrease or decrease the amount due under the CONTRACT DOCUMENTS or the
time required for performance of the WORK, an equitable adjustment shall be authorized
by CHANGE ORDER. . . .
The ENGINEER, also, may at any time, by issuing a FIELD ORDER, make changes in
the details of the WORK. The CONTRACTOR shall proceed with the performance of any
changes?nThe WORK so ordered by the ENGINEER unless the CONTRACTOR believes
tSuch FIELC.ORDER entitles him to change in CONTRACT PRICE or TIME, or both, in
which event he shall give the ENGINEER WRITTEN NOTICE thereof within seven (7)
days after the receipts of the ordered change. Thereafter the CONTRACTOR shal. docu-
ment the basis for the change in CONTRACT PRICE or TIME within trurty 30) days. The
CONTRACTOR shall not execute such changes pending the receipt of.an executed
CHANGE ORDER or further instruction from the OWNER.
• CHANGE IN CONTRACT PRICE. The CONTRACT PRICE may be changed only by a
CHANGE ORDER. The value of any WORK covered by a CHANGE ORDER or of any
claim for increase or decrease in the CONTRACT PRICE shall be determined by one or
more of the following methods in the order of precedence listed below:
(a) Unit prices previously approved.
(b) An agreed lump sum.
(c) The actual cost for labor, direct overhead, materials supplied, equipment, and
ether services necessary to complete the work. In addition, there shall be
added an amount to be agreed upon but not to exceed fifteen (15) percent of
the actual cost of the WORK to cover the cost of general overhead and profit.
• TIME FOR COMPLETION AND LIQUIDATED DAMAGES. The date of beginning and
the time for completion of the WORK are essential conditions for the CONTRACT DOCU-
MENTS and the WORK embraced shall be commenced on a date specified in the NOTICE
TO PROCEED. . .•••*„
The CONTRACTOR will proceed with the WORK at such rate of progress to insure full
betSerthe'cONTRACTOR and the OWNER, that the CONTRACT TIME for the comple-
tion of the WORK described herein is a reasonable time, taking into cons.derat.on the
average climatic and economic conditions and other factors prevailing in the locality of the
If the CONTRACTOR shall fail to complete the WORK within the CONTRACT TIME, or
extension of time granted by the OWNER, then the CONTRACTOR will pay to Ihe
OWNER the amount for liquidated damages as specified in the BID for each calendar day
that the CONTRACTOR shall be in default after the time stipulated in the CONTRACT
DOCUMENTS.
314
-------
The CONTRACTOR shall not be charged -with the liquidated damages or any excess
costs when the delay in completion of the WORK is due to the following and the CON-
TRACTOR has promptly given WRITTEN NOTICE of such delay to the OWNER or EN-
GINEER..
• CONTRACT WORK HOURS AND SAFETY STANDARDS ACT — SAFETY AND
• HEALTH. The CONTRACTOR shall not require any laborer or mechanic employed in the
performance of the contract.to work in surroundings or under working conditions which are
unsanitary, hazardous or dangerous to his health or safety, as determined under construe-
tion safety and health standards promulgated by regulations of the Secretary of Labor.
The CONTRACTOR shall comply with the Department of Labor,-Safety and Health
Regulations for Construction promulgated under section 107 of the Contract Work Hours
Safety Standards Act (40 U.S.C. 327 etseq.),
I BID BOND |
KNOW ALL MEN BY THESE PRESENTS, that we, the undersigned, .
— — -'' as Prin-
cipals, and ' '. _as Surety, are-hereby
.held and firmly bound unto • . as OWNER
in the penal sum of for the payment of
which, well and truly to be made, we hereby jointly and severally bind ourselves suc-
cessors and assigns.
Signed, this .' • - . day of 19 ,
The Condition of the above obligation is such that whereas the Principal has sub-
mitted to : ; - a certain BID, attached hereto
and hereby made a part hereof to enter into a contract in writing, for
the . .•..'"'':..
NOW, THEREFORE,
(a) If said BID shall be rejected, or
(b) If said BID shall be accepted and the Principal shall execute and deliver a con-
tract in the Form of Contract attached hereto (properly completed in'accordance with
said BID) and shall furnish a BOND for his faithful performance of said contract, and
for the payment of all persons performing labpr or furnishing materials in connection
therewith, and shall in all other respects perform the agreement created by the ac-
ceptance of said BID,
then this obligation shall be void, otherwise the same shall remain in force and effect; it
being expressly understood and agreed that the liability of the Surety for any and all claims
hereunder shall, in no event, exceed the penal amount of this obligation as herein stated.
The Surety, for value received, hereby stipulates and agrees that the obligations of said
Surety and its BOND shall be in no way impaired or affected by an extension of the time
within which the OWNER may accept such BID; and said Surety does hereby waive notice
of any such extension.
IN WITNESS WHEREOF, the Principal and the Surety have hereunto set their hands
and seals, and such of them as are corporations have causey their corporate seals to be
315
-------
hereto affixed and these presents to be signed by their proper officers, the day and year
first set forth above. • ,
. (LS.)
Principal
Surety
By:_
PROVIDED, FURTHER, that the said Surety'for value received hereby stipulates and
agrees that no change, extension of time, alteration or addition .to the terms of the contract
or to the WORK to be performed thereunder of the SPECIFICATIONS accompanying the
same shall in any wise affect its obligation on this BOND, and it does hereby waive notice
of any such change, extension of time, alteration or addition to the terms of the contract or
to the WORK or to the SPECIFICATIONS.
PROVIDED, FURTHER, that no final settlement between the OWNER and the CON-
TRACTOR shall abridge the right of any beneficiary hereunder, whose claim may be un-
satisfied.
IN WITNESS WHEREOF, this instrument is executed in counterparts,
each one of which shall be deemed an.original, this the _ _
dav of .19 •
ATTEST:
Principal
(Principal) Secretary
(SEAL). Bv , . (s)
(Address)
Witness as to Principal
(Address)
Surety
ATTEST • by_
Witness as to Surety (Address)
(Address) . -
NOTE: Date of BOND must not be prior to date of Contract. If CONTRACTOR is
Partnership, all partners should execute BOND-.
IMPORTANT: Surety companies executjng BONDS must appear on -the Treasury
Department's most current list (Circular 570 as amended) and be authorized to transact
business in the State where the PROJECT is located.
316
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PAYMENT BOND
9
KNOW ALL MEN BY THESE PRESENT: that
(Name of Contractor)
(Address of Contractor)
(Corporation, partnership or individual)
, hereinafter called Principal, and
(Name of Surety)
(Address of Surety)
hereinafter called Surety, are held and firmly bound unto
(Name of Owner)
(Address of Owner) . - ,
hereinafter called OWNER, in the penal sum of ; • •'. Dollars, $(
) in lawfulmoney of the United States, for the payment of which sum well and truly to
be made, we bind ourselves, successors, and assigned, jointly and severally, firmly
by these present.
THE CONDITION OF THIS OBLIGATION is such that whereas, the Principal entered
into a certain contract with the OWNER, dated the
_ : _^_ day of 19_ , a copy
of which is hereto attached and made a part hereof for the construction of:
NOW, THEREFORE, if the Principal shall promptly make payment to all persons, firms,
SUBCONTRACTORS, and corporations furnishing materials for or performing labor in the
prosecution of the WORK provided for in such contract, and any authorized extension or
modification thereof, including all amounts due for materials, lubricants, oil, gasoline, coal
and coke, repairs on machinery, equipment and tools, consumed or used in connection
with the construction of such WORK, and all insurance premiums on said WORK, and for
all labor performed in such WORK whether by SUBCONTRACTOR or otherwise, then this
obligation shall be void; otherwise to remain in fullforce and effect.
PROVIDED, FURTHER, that the said Surety for value received hereby stipulates and
agrees that no change, extension of time, alteration or addition to thfe terms of the contract
or to the WORK to be performed thereunder of the SPECIFICATIONS accompanying the
same shall in. any wise affect its obligation on this BOND, and it does hereby waive notice
317
-------
of any such change, extension of time, alteration or addition to the terms of the contract or
to the'WORK or to the SPECIFICATIONS.
PROVIDED, FURTHER, that no final settlement between the OWNER and .the CON-
TRACTOR shall abridge the right of any beneficiary hereunder, whose claim may be .un-
satisfied. . • .
IN WITNESS WHEREOF, .this instrument is executed in counterparts,
each one of which shall be deemed an original, this the _ day of
' , 19 .
ATTEST:
(Principal) Secretary
(SEAL)
Principal
By
.(s)
(Witness as to Principal)
(Address)
(Address)
ATTEST:
(Surety) Secretary
(SEAL)
Witness as to Surety
(Address)
Attorney-in-Fact
(Address)
NOTE: Date of BOND must not be prior to date of Contract. If CONTRACTOR is
Partnership, all partners should execute BOND.
IMPORTANT Surety companies executing BONDS must appear on the Treasury
Department's most current list (Circular 570 as amended) and be authorized to.trans-
act business in the State where the PROJECT is located.
318
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PERFORMANCE BOND
KNOW ALL MEN BY THESE'PRESENT: that
(Name of Contractor)
(Address of Contractor)
(Corporation, Partnership, or Individual)
_, hereinafter called Principal, and
(Name of Surety)
(Address of Surety)
hereinafter called Surety, are held and firmly bound unto
(Name of Owner)
(Address of Owner)
hereinafter called OWNER, in the penal sum of ' • ' Dollars,
$( ) in lawful money of the United States, for the payment of which sum well
and truly, to be made, we bind oursejves, successors, and assigned, jointly and
severally, firmly by these present.
, . THE CONDITION OF THIS OBLIGATION js such that whereas, the Principal entered
into a certain contract with the OWNER, dated the
; •• • - day of • 19 , a copy
of which is hereto attached and made a part hereof for the construction of:
• NOW, THEREFORE, if the Principal shall promptly make payment to all persons, firms,
SUBCONTRACTORS, and corporations furnishing materials for or performing labor iri the
prosecution of the WORK provided for in such contract, and any authorized extension or
modification thereof, including all amounts due for materials, lubricants, oil, gasoline, coal
and coke, repairs on machinery, equipment and tools, consumed or used in connection
with the" construction of such WORK, and all insurance premiums on said WORK, and for
all labor performed in such WORK whether by SUBCONTRACTOR or otherwise, then this
obligation shall be void; otherwise to remain in full force and effect.
319
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-------
INDEX
2,4,5-T 150
2,4-D 138,143,149,150
attainable uses 6,39
automatic water sampler 173
*
acid neutralizing capacity 55,56
acid rain 38,55,155
acidic deposition 38
acidification 155,159
.activated 95,96,102 "
advisory Committee 67,165,166,167,169,
187,189,190
aeration 34, 55,128,130,133,181,189
aerial photographs 43,169
aesthetics 2, 3,13, 38,39, 57, 83,135, 204
aging 14,24,28,29
agricultural practices 10,15,23,45,56,108,
' 111,112,113,115,119,135,152,154,168,
169,178,181.184,185,194
Agricultural Stabilization and Conservation
•Service 115,194 •'->'
algae 7,11,14,23,24,26,35,36,38,39,40,
41,44,45, 46, 54, 56, 57, 60, 63. 69. 71, 81, 83,
89.90,95.114.115,119,120,121.122,123,
125,126.127,128,130,133,134,135,140,
142.144,146, 152.153.155.161,163,166,
170,171,175,176.180,182
algal biomass 11,23,54,57,126,171
algal blooms 13, 23. 25,38, 55, 61,63.70,71,
87, 89. 93, 95,105,1-19,121,122,123,125,
126,127,130,135,136,138,143,150,152,
153,154,178,181
algal cells 11.121,122,126,127
algal concentration 40,60,87,89
algal control 123,131.133,136,137
algal die-off 55
algal growth 53. 54, 56, 60, 70, 71, 77, 87. 88,
95, 98; 121.122,126,176
algal production 3,19,21,23,25.33,60.70,
71,'123
algicide application 118,121
algicides 33.122,133,134,153,189
alkalinity 46,55.56,123,127,158,171
alligatorweed 135.136,141,143
alligatorweed flea beetle 143
alum 89,90,115,122,123,125,145,152,
180,181.182,183, 184, 185,187, 189.190.
193.196.197.198
ammonia 12,98.149
ammonia nitrogen 98,171,174
ammonium nitrogen 56
animal waste management 115,185
Annabessacook Lake, ME 114,115
anoxia 25,55,89
Aquascreeri (fiberglass) 140
aquatic weeds 14, 36, 71,93, 95,144,147,
149,161.170.171,189,203
Arizona 154 -. .
Arkansas 103,141
artificial circulation 3,33,63,121,127,128,
153
assessments 35,96,103,154,196,203
atmosphere 9,10.19, 22. 24, 63,127,128
bacteria 9, 24, 27, 50, 71, 94, 95, 97, 98,106.
130,161
basin shape 7,15,28,33,89,118,119,170
bathymetric map 137
benthic invertebrates 139,140
benthic zone 8 •
best management practices 14,93,107,108,
109,110,111,112,113,116. 205, 231-248
biochemical oxygen demand '9,43,45
biofliters 96
biological controls 33,111.136.141,144,189
biological indicators 56
biological productivity, 12,13,16,23,28,31 ,
biomanipulation 130,132,133
biomass 11,13, 21, 23, 33, 54.57, 60,126,
150,154,171
biota 7,9.33,130,147
blooms 13,23,25.38,55,61,63,70,71,87,
89, 90,93, 95,105,121,122,123.125,126,
127,130.135,136,138,143,150,152,153.
154.178,181
blue-green algae 23,53,54,56,57,61,63.87,
90,121,127.133,134,143,153.163.176
boating 2.38,39,119,135,161,162,163,
169,189,197. 203,208, 209
bond 5.197, 204
budgets 45,46,168
buffer strips 114,185
Bureau of Reclamation 195
capital costs 109,152,180,182
carbon dioxide 21,22,127,128
Carlson Trophic State Index 60,62,81,82,
176, 177
carrying capacity 39,46
cattails 135,141 ' -
Cesium-137 52
Chara 57,140
Chautauqua Lake, NY 146
chemical analyses 56,199
chemical and biological characteristics 169,
55-58
chemical oxygen demand 9
chlorophyll 21,44, 57, 63,70, 71, 87
Chlorophylls 54,57,60,70,71,73,80,81,83,
84. 87, 88, 89. 90, 91.171,176,180
Clean Lakes Program 120,163.166.167,169,
194,196
Clean Water Act 95,194
climate 2.18, 28,33, 89,141,144,147,150.
197
cluster systems 101 .
Cobbossee Lake, ME 114,115
color 2,36,128,153
Colorado 13 .
conductivity 46,47,49,171
321
-------
Connecticut 90
conservation 15,33,103,104,195
conservation districts 43.-196
conservation tillage 109,111,114,181,185
construction 2,45, 94,100,101,-107,108', 112,
115.135.162,163,164,167,169,178,181,
184.185.187,194,197,198, 205
consultant 4,41,42,43,50,53, 60, 65, 66, 67,
70,73. 80, 81.164,165,166,167,168,169,
172,178,179,184.187,190,191,192,193,
194,196,197,199
contract 193,197,204
contractor 42.102,103.109,112.191.192.
193,194,196,197,198,199
control strategies 43
coontail 138,140,142
copper 125,133,134,149
copper sulfate 114,133.134,149,150,153,
181
corrective stocking 155
costs 13,75,101,103.104,108,109.117,
118,120.123,125,126,127,129,130,133.
134.137,139,140,144,146,147,148.150,
151,152,158,159,167.168.180.182,184.
185.189.197
critical area 112,113
crop rotation 112,185
Crustacea 130,149
East/West Twin Lakes 115
ecology 7,9,31,192 ' .
ecoregion 3,40,54,60,119,154
ecosystems 5,7,9,10,27,33,136,155,182
effluent 45,50,100,114,168,185,190
electroshock 59
elodea 141
emergents -135,136
endothall 149
EPA 95, 96, 99,102,103,106,112.115,120,
147/151,152,163,165,166,168,169,171,
176,190,194,196,204
epilimnion 17,18,19, 24.71,129.130.153
erosion 14,28,38,43.53,60,108,109,111,
112,135,137,163,164,167,174,178, 184,
185,187,192,204
Eurasian watermilfoil 135,138,151,142,145,
146, 149
eutrophic 2,13, 25, 28, 29, 33, 41, 50. 55, 57,
60, 62, 63, 83, 84, 87, 88, 90, 91,115,119,129,
133,151,152,175,176,190
eutrophication 2,5,23,28,31,56.60,71,73.
75.76,77, 80, 81, 83, 87, 90,152,155,176
evaporation 10,49,75,174
export coefficients . 45,77
Dartek (nylon) 140
decomposition 14..19,23,24,25,27,31.50.
98,150
Delphi process 4,39.67
density 16,17,18,19,20,21,24,57,131,133.
142,143.144,146,151
Department of Commerce 195
Department of Housing and Urban
Development 195
Department of Interior 195
dastratify 19,34,128,130.153,175
detention basin 90,152,180.185
diagnosis 43.44.45.46,63.65.73.154,163,
194
diagnostic study 61.63,154,166,167
diagnostic/feasibility study 119
dilution 31.96,126.189
diquat 149,150
discharge rates 94,95
disposal sites 135,197
dissolved oxygen 9,12,14,19,22,24,25,44,
46.53.55, 63, 89. 94.95.122,125,127.133,
134.135,139,140.150.155.169.171.175.
176,189
dissolved solids 56
diversion 11,31. 63.66. 87. 89, 96,114,115,
120,122.123.136,153.185
downstream 20,126,128.143.189
drain field 51,97,98.99,100
drainage 3,12,13, 23,38,39,45, 62,63.76,
77,93,105.111,112,119,135,152,153.155.
169.178
„ drawdown 33,39,131.138.139,189
dredging 14,38,52,58.124.125.135.136.
137,153,171.180,181,182,183,184,188,
189,190,193,196,197i198
drinking water 2,38, 90.120; 128,151,152,
153
drying 138.139
dyes 139,140
fall overturn 19,89
Farmers Home Administration 195
fecal coliform 115 , '
fertilizer 12,23,95,98,106,108,109,111,
114,145,195
fiberglass 139,140
filters 38. 95, 98, 99.100,101.111,116,130,
152,153,185
fish 2,7.13.14.19, 23. 24, 25, 26, 27, 31,33,
38,39,43,46, 59, 60, 70,119,130,131,133,
134.138,139,141,142,143,144,146,147,
149,154,155.156,157,158,164,168,169,
•171,182,190,195
Fish and Wildlife Service 2,193,195
fishkills 12, 23. 38, 55, 61,63,94,134,139,
203
flocculation 23,90
Florida 4J. 57. 60.130,136,137.141.142.
143,144.147.150
fluoridone 149 '
fluorometer 49
flushing 31,71, 84,88,96,126,181,189
food chain 26,131,189
food web 14. 22, 25, 26, 27,130,131,133
Forest Service 195 . .
freezing 18/138,139,158
funding 164,165,166.167,168,194.196
fungi 24,27
gage 46,75,163.173
gas exchanges 9,19
geology 2.9,13.15,33,40,77,169,195
Georgia' 136,141
glacial lakes 15,30
glyphosate 149
granulated active carbon 152
grass carp 34,141,142,143,144,150
grassed waterways 111,185
grazers 26,130
322
-------
Great Lakes 18,28
groundwater 10, 44,45,46, 47,'48,49, 50, 51,
75, 76, 77, 94, 98, 99,100, 109, 115, 156, 158,
173,178,189
*
habitat(s) 7,14, 24,31,33,59,121,136,143,
150,155,135,205
hard water lake 123,134
•harvester 144,145,146,150
harvesting 7,33,34,38,58,119,141,144,
145,146,150,153,181,189,193
herbicides 12,14,33,38,55,106,118,119,
125,136,137,141,142, 143,144,145,146,
147,148.149,150,151,182,189,193
hydraulic residence time 9,11,14,16,22,28,
33, 45, 81, 84, 87. 88, 89, 91,175,179
hydrilla 135,136.137,141,142,144,150
hydrologic 7,9,10,69,71,90,143,157
hydrology 13,33,75,76; 80
.hypereutrophic 28,29,73,83, 84, 87.88,91
.hypolimnetic 20,29,89,128,152
hypolimnetic aeration 31,115,128.129,153,
155,189
hypolimnetic oxygen 19,24,71,88,94
hypolimnetic withdrawal 31,129,130,189
hypolimniori 17,18,19,24,25,51,55,62,89,
128,129,133.153,175
Illinois 39,142
implementation 5,43,56,60,63,65,108,109,
119,125,136,154,155,166,179.180.187,
191^192.193,194,197.198
Indiana 39
infilling 38 •
inflow 9,10,12,15, 17.20, 25, 43,44,49, 51,
62. 73, 75. 76, 80, 81, 84, 85, 88, 89, 90,91,95,
126,154,173,179.199
insects 3,39,141,143.147
integrated pest management 111,112
iron 25, 50,51. 89, 90,122,127,128,130,
152.153
irrigation 75,77,196
Kezar Lake, NH 88,89
Wmmel Creek 162,172,178.179
laboratories 51,157.168,171,199
LaDue Reservoir, OH 145
lagoons 94,96,101,116
lake associations 4, 7, 38,39, 42,43, 93,96,
108,111,112,113, 114,116, 118,161,164,
165,182,192,196,198, 203.204
Lake Baldwin, FL 144
lake basin 3,7,11,28,40,87.163
Lake Conroe, TX 141
Lake Evaluation Index 60
Lake LJIIesjon, Sweden 130
Lake LJIIinonah, CT 90,91
Lake Moray, VT 77,79,80,89,90
i Lake Superior 28
' Lake Trummen, Sweden 125
Lake Washington, WA 87,96,114,116
land use 2,5, 38, 40, 43, 45, 62. 74, 77r78. 79.
80, 89,94,109,112,114,116, 152,167, 169,
173,178,184,204,205
leach field 115
LeadT210 52,63
light 14,22, 23, 24, 26,54, 57, 60, 71, 81, 88,
120,121,127,135,136,137,139,140
lime 130,156
liming 39,156,157,158,159
limnology 9,42,54,120,192
littoral zone 8,14 •'..,.
loading 44,94,153
Long Lake, WA 88
longevity 90,109,122,134,180,181,182,
184,189,198
Louisiana 136,143
Lynn Lake 161,162,163,164,165,166,167,
168,172,173,175.176,177,178,179,180,
182.184,185,187,189
macrophytes 12,14, 21, 22, 26,35,38,39, 41,
46,56.57,58,60,95,120,125,135,136,137.
141.144,151,161,182,197
Maine 114
maintenance costs 109
management 1,2,3,4,5,6,7,9,13,14,19,
23,31, 33, 34.38,39,40, 41,42, 43,45, 55,56,
59,61, 66,67,70, 74,80, 93.106.107,108,
109,110.111,112,113,114.115,116,117,118,
119,120,121,133,134,136,138,142,143,
147,151,152,153,154,155,159,161,163,
164,165.166,167,169,170,171,175,179,
180,181,182,184,185,187.189,190.191,
192,193,194,195,196,197.198,199,204,
205,209
manganese 25,127,128,152,153,171
manmade causes 41
manmade sources 12,41 '
marginal zone 8,14
marshes 153
maximum depth of colonization (MDC) 136,137
mean depths 81,89,125,130,169,179
mechanical stream doser 157,158
mesotrophic 28, 29, 83,88,90,91,180,190
metalimnion 17,18.19,24,51,63,89,171,
182
metals 25,107,125
metric system 1
Mirror Lake, Wl 61,62,63,64,65,66
mixing 14,16,17,18.19, 20, 23. 24, 25, 53,
55,57.63, 88,127,175,178,193
modeling 56.69,70,72,73.75,76,77,81,84,
172
models 41. 69, 70, 71. 73. 74.77. 80, 81,84,
87,88.89,91.131
monitoring 5.44. 51, 60,63, 69, 70, 71, 73.74,
75.76, 77, 80, 89, 90,91,113,125,167,170,
171,172,174.175,177.178, 190.192.193.
,194.196,198.199,200. 201,209
morphometry 13,69,80
mound systems 99,116
.National Pollutant Discharge Elimination
System 94,95
National Oceanic and Aeronautic Administration
174
National Science Foundation 120
323
-------
natural background 119
natural causes 41.55
nitrate 98
nitrate nitrogen 56,171,174
nitrogen 12,19,21,22, 23, 25,3B',-S6, 60, 71,
96, 98,109,121,133,163,171,174,175,178
nominal group process 4,39,66,67
nonpoint sources 5,77,80,84,94,104,105,
106,107,112,113.114,115,116,167,174,
178,194,204.205
nonstratified 123
nonvegetative soil 112,114
North American Lake Management Society
113.192.204
North Twin Lake, Wl 57
northern lakes 2,81
nutrient budget 51,172
nutrient loading 11,12.32,33,50,56,69,70,
74. 81,118,119.120.133,144,173,174
nutrients 2,3,7,10,11,12,13,14,19,21,22,
23,24. 25.26, 27,28,29,31.32,33, 38, 40,41,
44,45, 46.47. 50,51,53, 56, 60, 62, 66, 69,70.
71,74,77.81, 89. 94,95,96.98, 99,104.105,
106,107.108.109.110.111,112.113.115.
116,118,119,120.121.122,123,125,126,
127.129,130.131.133,134,135.136,138,
143.144,145,146,147,150,153,154,163.
164,169,172,173,174,175,177.179,180,
181,185,189,195.197
nylon 133,139.140
Occupational Safety and Health Administration
193
Odors 12,23,36, 38. 57, 94. 95.120,121,151.
152.153,203
oligotrophic 13,24, 28. 29,33,41.57,60,73,
83. 84,90
Onondaga Lake. NY 87
operational costs 109
ordinances 112.113,184.187.205.208
organic matter 2. 9,12,13.14,19, 21,22,23,
24,25, 26, 27,28,38,43,45, 46, 71,94,95.96,
98.104.106.107,109,111.116.118,119,120,
130,133,135,144,145,146,147,150,172,179
organics 107.113,120.152,153
outflow '9,10.17.38,73.75. 76,77, 80, 81, 89.
9.1,199
outlets 16,20,29,46,75,76,77,81,93,94,
126,130,172,174,177
oxidation 31.101,116,130,189
oxygen 9.12.19,21.22,23.24,25.94.95,96.
98.127.128,129,133,139.153.178
oxygen depletion 12,19,23,24,25,38,53,55,
88,89.94,125,134.139,140,150
particulates 9.14,16.22,23,122
pasture management 108,185
pelagic zone 8,14
permits 5,77. 94,95,191,193.196,197, 208
pesticide 12,14,106,108,109,111.114.133,
147.152.195
pH 46,55.56.74,80,123,127,130,155,156,
157,171
Phase I Diagnostic/Feasibility Study 165,166,
194
Phase I Grant Application 165,166,168,169
Phase II Lake Restoration Program 165,166
phosphorus 12,19, 21, 22, 23, 25,31, 45, 50,
51, 55, 56, 60. 61, 62, 63, 66, 70,71, 73, 74,75,
76,77, 80. 81. 83, 84, 85, 87, 88, 89, 90,91, 95,
96, 98,105,109,114,115, 119,121,122,123,
125,126,127.128,130,137,146,152,153,
157,163.171,174,175,176,177,178,179,
182,184,185,187,189,190,198
phosphorus budget 50, 71,74, 76,78, 80, 85,
86,89,178,184
phosphorus loading 23, 45, 63, 71, 74, 75, 76,
77/80, 82, 84, 87, 88. 89, 90,91.105,122,126,
130,146,178,179,189
photic zone 22,25,57,137
photosynthesis 21,22,24,26,81,127,133
physical parameters 52,53,54
phytoplankton 12,14,21,22,23,27,60,121,
171,176
Pickerel Lake 53,54 •
piezometer (mini) 48,51
plankton 13,23,31
planktonic algae 14,21
plants 7,9,10,11,12,14,19, 21,22, 23, 25,
26, 27, 31,33,38.39,44,45, 46, 56. 57,58,90,
94, 95,96.100,109.111,114,118,119,120,
121,135.136,137,138,139,140,141,142,
143.144,145,146,147,148,149,150.151,
152,155,162,163,167,168,169,171,177,
178,184,185.187,189,190,196
plastic 47,54,100.139
Pleasant Pond. ME 114.115,116
point sources 70,74,75,76,78,79,80,87, 88,
89,90,93, 94, 95, 96,105.106,110,114,116,
177
pollutant 5.12, 71.75,93, 94. 95,106,107,
116,169,172.179,181,184
polyethylene 139,140
ponds 15. 94.101,114.115.116,122.125.
135.136,140.143,150.162
pondweeds 135.138.141.142,146,150
postrestoration 87,88,194,198,199 '
Potamogeton 138,140,141,142
precipitation 9,10,18,31,38, 75, 76, 77, 90,.
119,121,122,128,130,174
predator 24,26,59.130, .133,155
problems 1. 3,4. 5.7,9,14, 23.33,34,35,37,
38,39, 40.41, 42,43,^44, 45, 46, 50, 53, 56, 57,
59, 60. 61. 62, 63, 65. 66.69,70.71. 75.76, 81,
89,90,93,95,98,99,100,103,105,106,109,
110.112,113.114,117,118,119,120,121.
123,125,127,128,133,134,135,138,139,
140.144,145.147.150,151,152,153,154.
155,161,163.164,165,166,167,168.170,
171,176,178,180,181,182,187,191.192,
194,199,203, 204,205, 208,209
profundal zone 8
propagation 135
public 35, 67, 94.100,102,103,105,114.141,
161,163.164,165.166,167.168,169,170,
180,190,191,192,193,194,196.198, 203,
204, 205, 208
recreation 2,15,35,39,83.115,116,135,
136,154,163,167,168,169,170,189,195, 203
reservoirs 1.2,4.7,9.10,13.14.15.16.20.
21.25,27,28,29,31,33.34.38.40.46.51.52,
53, 60. 67.70. 71,73, '74.76,80,81.83, 88, 90,
91.117.118.119.120.121,122,127,128,129,
134.135.136.142.143,145,151,152,153,
154,173.199
324
-------
residence f/me 10,11,74,81,126
respiration 9,19, 21 ,.'22, 24 ^
restoration .3,5,6,9,19,23,31,33,34,38,39,
41, 43, 53,59, 60, 63, 65, 66, 70, 80, 84, 85, 87,
88, 89, 90,93, 108, 110,111, 114,115,117, 118,
119,120,121, 134,147, 151, 152, 153,154,
155,159,161,163,164,165,166,167,168,
171,178,190,191,192,193,195,196,197,
198,199,203,204,209 ,
RIPLOX 130 .
rototilling 136,137
runoff 2, 9, 10, 44, 45, 74, 75, 76, 77, 78, 90,
94,106,107,108,109,111,112,115,125,133,
151,163.174,181,184,185,187,193,195
Rural Clean Water Program 194
156,157.158,168,172,173,174.177,185,
193,195,196,198,199 ; .
streambank 111,112,184.195,198
streamflow 56, 62,73, 76,95,172,173,177,
180, .181,195
street cleaning 114
submergents 57,135,136 , ;
surface area 3,13,15,40,43,61,76,81,89,
105,107,1*2.175
suspended solids 54,171,174
swimming 2,38,39,41,83,118,119,139,
161,169,203.209
symptoms 4,5,7,24.34.35.118.120,175
sampling 51, 53, 55, 56, 73, 77,154,170,171,
173,199
Secchi 45,54,60,84,136,137.171.176
sediment 7.9,14,19,22,23,24.25,27,28,
29,31,33, 38, 45, 46, 47, 48, 49,51, 52, 63, 71,
74, 77, 80. 81, 85, 88. 89. 94,106,107,108,
109, 1JO, 111,112,113.115,118, 119.120,121,
122.123,124, 125,126,127,128,130,134.
135,136,137.138,139.140,145,146,149.
150, 153,156,157,171,172,174, 175,176,
177,178,180,181,182,185.187.189,193,
197,198
sedimentation 14,23,24,27,46,52,76,77,
80. 81, 87, 88, 90, 91, 96,111.112.120.164.
180,181,185.187
seepage meter 47,51
septic system 50,94,96,97,98,99,100.107,
115,164,167,169,184,208,209
setback zone 204
sewage 23,41.78,79,80.87,88,89,94,97,
^98,100,103,114.115,195.199
sewer 43, 45, 50, 62, 63, 80, 87, 90, 95, 96,
100,101,102,105.115,168,190,196
shading 33,38,139,140
Shagawa Lake, MN 88
shallow 2,13,14,16,22.24,39, 51.53,55.
59,71. 81. 88.100,119.120,123,128,135,
137,150,153.157,175,189
Shoreline 3,14,15.28,39,51,75,76,77,80,
89.90,135,164,184,196,198
Silt 2,12,14, 23.28, 29, 62. 71.93,94,95,
111,116,118,119.120.122,135,136,139.
140.152,153.161, 170, 171.177,179.181.189
slopes 47,98,99,100,112
sludge 50,95,96,97,102,125,185
soft water lake 123
soil 2.3. 9.10.12.13.14,15, 22,28.31.33,
38.40. 43.44, 47,50,51. 78,79, 80. 93,98, 99,
100.101.107,109.111,112,115.119,155,
158,169,178.184,185,194,195
Soil Conservation Service 2.44,111,112,168,
178,185,194 • .
solids 50.96.97.98,99.171
soluble reactive phosphorus 56,171,174,184
spills 152
stilling well 46
stocking 131,133.141.142,154,155.157
storage capacity 145,153
stratification 16,17,18,19,33,53,73,89,127,
129,175,189
Stream 9,10,12,14,25,39,43,44, 46, 49, 56,
62. 73. 74, 75, 76,77,94,95. 96,105,106,108,
111.112,113.115,119,125,136,152,155,
tastes 23,38,57,120,121,128,151.152,153
temperature 16/17,18,19, 20, 22, 23, 24,25,
44,46, 47,49, 53. 55.127,150.155.158,169,
171,175,193
terraces 205
tertiary treatment 87,88,96,185,187,189,190
thermal stratification 16.17,18,19,33,53,73,
127,129,175,189
thermocline 17,19 ,
topography 2.9,13,15,169,184-
total Kjeldahl 56 '
toxicity 123,134,147,149.157,158,171
toxics 14, 71,94,99,126.139
transparency 13.14.22,40,46.54.60,63.70,
71, 73, 80,81. 83.84,87, 88, 89, 91,114,123,
126,127.133,136,137,142,171.180
transpiration 10
tributary 9,14,41.46,73,75,76,94,162,185
trickling filters 97,101,116
trihalomethanes (THMs) 151,152,153
trophic state 24,28,30.31,41,46,59,60.62.
71,81,83,84
turbidity 13,14,28,38,40,54t 60,81,84,105,
120. 125, 127, 135,136, 143. 149. 157
turnover 25,129,157
U.S. Army Corps of Engineers 124,135,147,
.153.193
U.S. Geological Survey 44,169,195
university 50,196,204
upstream 21,74,77,91,162,181,185
user 1,3,4,35, 39.40.41,43,56, 63, 67, 69,
83, 89,114,115,117,119.120.135.146.147,
149,151,152,154,161.163.164,170.190,
191,198,203,204,209
vegetation 9,12,13,15,31,40,111,112,118,
141,143,145,146,147.196,198, 204
Vollenweider 84,179
Wahnbach Reservoir, W. Germany 90,152
waste 12,50, 51, 95,111,114,115,185,205,
.208
wastewater 9,11,12,23,28,31.43,44,45,
50,51,94,95,96,97, 98.99,100,101,102,
103,104,105, .116,152,154,162,168.169,
178,179,184
water balance 75,76,172,177.178
325
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water budget 46,47,74,75,76,78,80,173
water column" 11,16,17,18,19,20,22,23,24,
25,62, 63,71,73, 74,77, 80, 81, 89,115,122,
123,133,135,136,146,150.157,175,176,
181,198 '. •
water hyacinth 135.136,141,143.145.147.
149
water lily 57,135,138,141
water quality 2.3,9,10.12,13.15,16,21,23,
31,33,39,41.43,44,50,51, 54,55,56, 60, 61,
69,70,71.73.74.75.76, 77,81, 87,89, 90,93,
94,105,106,107,108,110.113,114.115,119,
120,150,152,153,155,157.167,169,170,
174,177,189,192,194,195,199,203
watersupply 9,15,39,75,77,90,118,127,
141,144.151,152,153
water table 10,47,98." 99,100,115
watershed 1.2.3.5,7,9.10.12,13,14,15.
16.20.22.23.25,27,28,31.33.34.38.40.41.
43.44.45,46,53.56, 61,62. 66,69, 70,71,73,
74,75.76,77,78,79, 80, 84,89,90, 93.94.96,
105,106,107.108.110,111,112,113,114,
115.116, 'IIS, 119.120.121,152,156.158,
161,165.166.167,169,172,173,174,175,
177,178.179.180,181,184.185.187,189, •
190.191,192,193,195,196,198.203. 204.
205, 209
watershed management 36,93,94,113,178,
180.184,186
waterways 111,135,136,147,181,185
wetlands 2,95,112,162,195.196
zoning 112,113.114, 204.205.206,208,209
zooplankton 23,24,26,27. 60,127,130,131.
133.155,171
326
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