&EPA
United States
Environmental Protection
Agency
Environmental Protection
and Assessment Division
Philadelphia, PA 19107
EPA/903/R/97009
May 1997
Proceedings of the Second Marine and Estuarine
Shallow Water Science and Management Conference
April 3-7, 1995
Atlantic City, New Jersey
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Regional Center for Environmental Information
US EPA Region HI
1650 Arch St.
Philadelphia, PA 19103
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Second Marine and Estuarine Shallow Water
Science and Management Conference
April 3-7, 1995
Holiday Inn on the Boardwalk
Atlantic City, New Jersey
Table of Contents
Preface i
Restoring Greenwich Bay: A Dynamic Partnership Approach to
Nonpoint Pollution Control
Susan C. Adamowicz 1
Classifying and Mapping Natural Phenomena in Coastal Environments
Using Remote Sensing and Geographic Information Systems
John D. Althausen, Jr 5
Communications and Information Management: Keys to
Performance Improvement in the Management of Coastal Habitats
Ronald C. Baird 8
An Ecosystem Model; Prediction and Regulation
A.Y. Benilov and T.G. McKee, Jr . 14
Enhancing Shallow Water Habitat Through Shoreline
Bluff Stabilization (1995)
Joseph A. Berg, Jr.; Edward W. Morgereth, Jr.;
and Peter Kotulak 36
Water Quality in Areas of Submerged Aquatic Vegetation (SAV);
Regrowth in the Magothy River, Chesapeake Bay
Peter Bergstrom 47
The Effect of Bulkheads on Fish Distribution and Abundance:
A Comparison of Littoral Fish and Invertebrate Assemblages
at Bulkheaded and Non-Bulkheaded Shorelines in a Barnegat Bay Lagoon
Donald M. Byrne 53
U.S.
Region 111
Center (SPM52)
|41 Chestnut Stre«t
Philadelphia, PA 19107
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Phytoplankton Chlorophyll A vs. Benthic Microalgal Chlorophyll
A in Estuarine and Coastal Waters: Implications for Remote Sensing
Lawrence B. Gaboon; Guy R. Beretich, Jr.; Janice E. Nearhoof : 57
Delaware's High-Level Tidal Marsh Impoundments as Fish Habitat:
Improving Fish Access and Survival While Maintaining Traditional
Impoundment Management Goals
John H. Clark 67
Research and Management Needs in the Mid-Atlantic:
The Mid-Atlantic Regional Marine Research Program
Sherri Cooper, Douglas Lipton, and Merrill Leffler 75
A Habitat Management Strategy for the Oyster Bay/Cold Spring
Harbor-Complex
Richard A. D'Amico 83
Use of Dredged Material for the Creation ofEelgrass
Habitat on an Underwater Terrace
Ryan Davis and Frederick T. Short 87
Jet-Spray9 Thin-Layer Overlays of Dredged Material
for Wetlands Rehabilitation and Creation
Troy Deal 93
Avoidance Reactions of Fishes in Oxygen, Temperature,
and Salinity Gradients
D. Dorfman, J. Berning, and B. Surgent 100
Enhancing Waterbird Habitat with Dredged Materials:
Some Suggestions for Improvement
R. Michael Erwin 106
Turning the Tide on Trash: Ongoing Efforts in Public Education
Brigitte Farren 109
The Simplification and Integration of Jurisdictional Constraints:
A CIS Approach to Estuarine Watershed Management
Andrew M. Fischer Ill
Sentinel Species: Trace Metal Ecotoxicology in the
Oyster Toadfish (Opsanus tau)
John W. Foerster, Scott D. Smart,
F. David Correll, and Douglas W. Edsall
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DDT Contamination in Commercially and Recreationally
Important Finfish and Shellfish Species from Estuarine
and Coastal Marine Waters of New Jersey
Michael J. Kennish and Bruce E. Ruppel 130
The Use of CIS and Remote Sensing in Coastal
Resource Management
Victor V. Klemas and Oliver P. Weatherbee 135
Improving the Environmental Management of
Dredging Projects in Shallow Water Habitat
Jonathan M. Kurland, Eric P. Nelson,
and Mary A. Colligan 139
Monitoring Land Cover Change in New Jersey's Coastal
Zone Across a Gradient of Human Disturbance
Richard G. Lathrop, Jr. and Kenneth Able 143
Benthic Primary Production within Shallow Water Sites
in Chesapeake Bay
H. G. Marshall, Susanne Wendker and K. K. Nesius 148
Ampelisca abdita: The Fickle Fiends of Ecotoxicology
Amanda Maxemchuk-Daly 152
Marine Border Control: Prepenetration Strategies
and Postpenetration Options
Susan G. Metzger and Karim A. Abood 160
The Effects of Dredged Material Disposal on Water Quality
in the Pooles Island Region of Chesapeake Bay
Bruce D. Michael and William D. Romano 165
Controlling Nitrogen Inputs into the Peconic Estuary System
Vito Minei and Walter Dawydiak 178
Community-Based Educational Outreach to At-Risk Urban Anglers
Kerry Kirk Pflugh 180
Review of Historical Tidal Wetlands of the Delaware River Estuary
Kurt Philipp, Judith Auer Shaw, Elizabeth Yacovelli,
and Leighann Von Hayen 184
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Local Government Role in Shoreline Management
Jeryl G. Rose, Todd A. Grissom,
John M. Carlock, and Donna E. Cesan
Hydraulic Clam Dredging Effects on Nearshore Turbidity
and Light Attenuation of the Chesapeake Bay, MD
Katherine Keith Ruf fin, Richard Everett,
and Douglas Forsell ............................................... 191
Development of a Dredged Sediment Contamination Reduction
Plan for the New York/New Jersey Harbor Estuary
Dennis J. Suszkowski ............................................. 199
Simulation of a Shallow Estuarine Environment
with a Novel Microcosm Design
Thomas W. Small and Stephen B. Gough ................................. 205
Competition, Niche Breadth and Niche Overlap in two Sympatric
Estuarine Killifishes: A Test of Ecological Theory
Craig Steele [[[ 212
Eastern Shore of Virginia Water Quality Consortium
Terry Thompson ................................................. 219
Docks as Shallow Water Refuge for Juvenile Blue Crabs
Jason D. Toft, Anson H. Mines, and Greg M. Ruiz ........................... 223
Impacts on the Marine Environment from the Shadows
of High-Rise Towers and other Structures
Michael P. Weinstein .............................................. 230
Dune Protection and Replenishment: The Andres Method
Stan G. Andres ................................................. 239
Assessing Shallow Water Conditions Using Imaging
Spectroscopy and Videography
Sima Bagheri [[[ 253
Development and Use of a Spreadsheet Model Predicting
Copper Losses from CCA Treated Wood in Aquatic Environments
Kenneth M. Brooks ............................................... 259
Shallow Coastal Lagoons as a Recruitment
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Otolith Based Indices of Relative Growth Rates of Juvenile Atlantic
Croaker as a Function of Environmental Quality and Estuarine Location
John S. Burke and David S. Peters 275
Minimizing Pollution in Shallow Water Habitats:
Water Quality-Eased Land Management for Local Government
Wesley R. Homer, Thomas H. Cahill, and Joel McGuire 278
The Baltic Macoma: Abundance and Distribution of an
Important Winter Food of Diving Ducks in Chesapeake Bay
Dennis G. Jorde and G. Michael Haramis 282
Coastal Marina Basins as Potential Fishery Habitat
with Special Emphasis on Nursery Function
M. E. Mroczka, P. W. Dinwoodie, P. E. Pellegrino,
T. A. Randall, and J. K. Carlson 289
Acanthamoeba (Protozoa: Acanthamoebidae) as an
Indicator of Sewage Pollution in Bermuda Inshore Waters
Donald A. Munson 297
The Ecological Condition of Estuaries in the Mid-Atlantic
and Gulf Regions of the United States
J. Kevin Summers 302
Intertidal Fish Assemblages in the Sheepscot Estuary, Maine
Maria J. Tort 304
A Cooperative Research Program Between the U. S. Naval
Academy and the U. S. Environmental Protection Agency
Mario E. C. Vieira 315
Effects of Bulkheads Made of Pressure-Treated Wood and
other Materials on Shallow Water Benthos in Estuaries
Judith S. Weis and Peddrick Weis 327
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PREFACE
This publication is a compilation of selected presentations from the Second Marine-and
Estuarine Shallow Water Science and Management Conference, held in Atlantic City, New
Jersey, on April 3-7, 1995. These presentations have been reformatted into an abbreviated
article format to facilitate then- dissemination.
The first and second shallow water conferences focused on recognizing the importance
of and defining shallow water habitats. The Shallow Water Committee, along with
participants at the first conference, developed a preliminary definition of shallow water.
Participants at the second conference refined the initial definition, defining shallow water as
the zone of maximum interaction between humans and critical biological resources. This zone
incorporates all marine and estuarine waters within 4m below Mean Low Water (MLW)
including the intertida) zone.
Topics at the second conference included a more in-depth discussion of the definition,
the functions and values of the habitat, and the impacts of shoreline alteration and dredging.
Participants also discussed different management practices. The various topics discussed at the
conference attracted a diverse group of participants, including environmental managers,
academics, consultants, and representatives from private interest groups. The conference
provided an opportunity for all these individuals to share their insight and own unique
perspective on the subject.
Different individuals value the shallow water zone for different reasons. Residents
may view the shallow water area as a place for recreation. Fisherman may view the shallow
water area as an excellent place to fish. Conservationists may view the shallow water zone as
invaluable since it is a nursery to many fish. Whatever the reason, a clear and concise
definition of shallow water must be instated in order to protect this invaluable area.
Promulgation of a definition of shallow water would also eliminate the inconsistencies between
federal, state, and local agencies that plague the management of shallow water. Through
discussion raised by presentations, conference participants developed the refined definition of
shallow water given above.
•Presentations also focused on the functions and values of the shallow water zone. For
example, the function of the zone can be a nursery to fish, while the value of that function is
the propagation of species.
Similarly, presentations explored the adverse impacts of shoreline alteration and
dredging on the zone. EPA studies show that dredged shallow water habitats can take up to
twenty years or more to return to their original condition. Therefore, prudent management
practices are essential to the preservation of the existing habitats. The meeting culminated in a
session on management practices that included tips on how to enhance, restore, and create
shallow water habitat.
We would like to acknowledge the Shallow Water Steering Committee and then-
affiliations: Atlantic Estuarine Research Society, Estuarine Research Federation, U.S. Army
Corps of Engineers, U.S. Environmental Protection Agency Region II, U.S. Environmental
Protection Agency's Chesapeake Bay Program Office, U.S. Fish and Wildlife Service, The
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Reilly Group, National Marine Fisheries Service, Atlantic Marine States Fisheries
Commission, Mid-Atlantic Fishery Management Council, Maryland Department of Natural
Resources, New Jersey Department of Environmental Protection, Delaware Department of
Natural Resources and Environmental Control, and TEVA Environmental Associates.
Special recognition is extended to Sharon Soppe, Rachel Raffile, Rahsaan McGlashan-
Powell, Darren Greninger, and Renee McLaughlin for their countless time and effort in
helping to complete this publication.
For more information about either the shallow water conference or this publication,
please write to or contact Ralph Spagnolo:
841 Chestnut Building (215)-566-2718
U.S. EPA Region ffl spagnolo.ralph@epamail.epa.gov
Philadelphia, PA 19107
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RESTORING GREENWICH BAY:
A DYNAMIC PARTNERSHIP APPROACH TO NONPOINT POLLUTION CONTROL
Susan C. Adamowicz
RI DEM/Narragansett Bay Project
291 Promenade St.
Providence, RI 02908
INTRODUCTION
A severe Nor'easter in December 1992 forced many areas of Narragansett Bay to be
closed to shellfishing due to sewage contamination. All of the areas reopened within a short
period of time except for Greenwich Bay, a 5 square mile region which was closed for 18 months.
This extended closure resulted in an economic loss of nearly $6 million, the majority borne by the
state's 500 full-time quahoggers. In addition to the lost harvest, quahoggers were forced to work
other areas of Narragansett Bay, regions both less productive and more exposed to the hazards of
winter winds and waves.
The storm's environmental and economic impacts prompted a variety of organizations to
join in an effort to restore Greenwich Bay. These groups include the City of Warwick, which
contains much of the Greenwich Bay watershed; Save The Bay, New England's largest
environmental advocacy organization; the RI Department of Environmental Management (DEM),
and OEM's Narragansett Bay Project, a National Estuarine Program. Other organizations
involved are the USD A Natural Resource Conservation Service, the University of Rhode Island
(URI) and the Rhode Island Shellfisherman's Association.
While the coalition is leading a variety of major actions, this paper focuses on problem
identification and sewage abatement.
PROBLEM IDENTIFICATION
Following the closure of Greenwich Bay, the RI DEM and US Food and Drug
Administration (1994) united to conduct a wet weather/dry weather study for the purpose of
identifying major fecal coliform inputs. The primary "hot spots" are shown in Figure 1 with
Hardig Brook, a tributary to Apponaug Cove, accounting for 50 - 90% of the fecal coliform loads
to the bay.
The RI DEM/US FDA study, however, only identified "hot spots" at discharge points to
the bay; the next step required identifying actual sources within each sub-watershed. For this
reason, the Narragansett Bay Project contracted with Dr. Ray Wright at the URI Environmental
Engineering Training Center to pinpoint sources within the Hardig Brook watershed.
From Wright's dry-weather data, one location in the lower portion of the Hardig Brook
watershed clearly dominated fecal coliform inputs. With further intensive sampling, Wright's team
identified a mill site with three direct sewage discharges. The mill site is now under an
enforcement effort and is in the process to tying into sewer lines that are already in the street.
During wet weather, however, the contamination pattern is very different. Intense rain
events cause fecal coliform levels to rise rapidly in the upper watershed. The resultant loadings
completely dominate inputs originating lower in the watershed. As a storm passes, loadings
rapidly decline. At first, Wright thought the source might be linked to surging at a specific
sewage pump station. A second wet weather study, however, revealed high bacterial
concentrations upstream of the pump-station.
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By performing a third wet weather study, the team identified a dairy farm as the primary
source of fecal coliform contamination in Hardig Brook. An effort is being mounted now to
provide the farm with best management practices (BMPs) to control animal wastes and onsite
erosion.
While Wright is still busy with his studies on Hardig Brook, the City has added four
streams along the bay's northern shore to his workplan. Wright began initial work on these
streams in the spring and summer of 1995. By December 1995, we should have a very clear
picture of the fecal coliform loads to Greenwich Bay from most of the major sources identified by
previous studies.
SEWAGE ABATEMENT
Local Support
Warwick city residents passed a $5 million dollar local bond referendum in June 1994 to
provide capital for bay-related projects. As a result, the City is now able to extend a sewer line to
a densely developed coastal area (with known septic system failures) in conjunction with a state
road reconstruction project. Stormwater mitigation efforts now have the solid footing of $1
million dollars for projects with an additional $500,000 for research. Another $1 million dollars
of the bond is being used to supplement an existing city-wide septic system repair program.
This last program is particularly important since 60% of the city (pop. 85,000) is on
cesspools or septic systems and few residents maintain their systems. We are addressing the
knowledge gap on septic system maintenance and repairs through brochures, neighborhood
meetings and door-to-door inspections in certain coastal neighborhoods. A colleague in DEM is
also testing out a model based on lot size, soil type and water use to quickly identify homes with
potential septic system failures or illegal discharges. Both the door-to-door work and a
preliminary test run of the model indicate that only 10% of homes have failing septic systems. If
the model can distinguish failures consistently, it would greatly increase the efficiency of
identifying problem systems and targeting bond repair funds.
Marine Sewage Pump-out Facilities
Sewage is also generated on the bay itself through marine sanitation devices (boat heads):
Greenwich Bay has some of the highest densities of recreational boats in all of Narragansett Bay;
Warwick Cove alone has over 2000 boats. To address this situation RI DEM secured Clean
Vessel Act funds for the construction of marine sewage pump-out facilities.
Seven pump-out grants were awarded to marinas in Greenwich Bay; two of these facilities
have already been constructed. We expect the remainder will be completed by the end of the
1995 boating season.
Ultimately, our objective is to get enough pump-out facilities constructed around
Narragansett Bay so that it will be eligible for EPA "No Discharge Zone" status. But rather than
rely solely on enforcement measures to gain boater compliance, the coalition is working with a
local television station to produce public service announcements, with marinas to participate in
promotional give-away contests and with boat shows to provide pumpout demonstrations. As a
result, in the last three years the public has gone from active disinterest to demanding easier
access to pump-out facilities.
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CONCLUSIONS
While this paper covers only a few aspects of our work in Greenwich Bay, other efforts
include work on eelgrass restoration and nutrient budgeting. The bottom line is that we're not
concerned only about fecal coliform and shellfish, but about the entire bay and its watershed.
People frequently ask what holds the coalition together. It is a result of the group's t
willingness to work together toward a common goal, to communicate freely on a regular basis
and to rely on each organization's expertise so that we always put our best foot forward. Most of
all, it is local support, a strong sense of place and pride, that keeps us looking forward to the day
when bay quality will be improved for quahoggers as well as native estuarine life.
REFERENCES
US Public Health Service, Food and Drug Administration 1994. Greenwich Bay, RI Shellfish
Growing Area Survey and Classification Considerations, April and June, 1993.
Davisville, Rhode Island, 98 pp.
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Greenwich Boy
Figure 1. Sampling Locations with Highest
Fecal Coliform Loadings
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CLASSIFYING AND MAPPING NATURAL PHENOMENA IN COASTAL
ENVIRONMENTS USING REMOTE SENSING AND GEOGRAPHIC INFORMATION
SYSTEMS
John R. Jensen and David J. Cowen
Department of Geography
University of South Carolina
Columbia, SC 29208
John D. Althausen Jr.
Department of Geography
University of South Florida-St. Petersberg
St. Petersberg, FL 3701
Oliver P. Weatherbee
College of Marine Sciences
University of Delaware
Newark, DE 19716
INTRODUCTION
It has often been suggested that before remote sensing secures distinction as a science, and
not a technique, several shortcomings must be resolved (White, 1992), including: (1) a better
understanding of the energy/matter interactions that do not create unique spectral responses;
(2) improved comprehension of the information received from the sensor platform (imagery) and
how it relates to actual ground information; and (3) improving the utilization of GISs so that they
are something more than just databases. Over the scope of this research it was evident that new
expertise and relationships were being uncovered that could help improve the understanding of
remote sensing as a science.
SIGNIFICANCE OF THE RESEARCH
The objective of the NOAA Coast Watch program is to develop a nation-wide GIS that
can relate coastal processes to the environments around them. The significance of this research,
to the Coast Watch program, is that it: (1) helps develop new techniques that can be used to
classify and map certain phenomena in the coastal environment; (2) documents change detection
techniques that can be used to monitor the coastal environment; (3) suggests modifications that
can be made to present Coast Watch protocol because of the influence of tidal stage; and
(4) demonstrates techniques that can be used to map estimates of sea level rise.
Two study areas in Berkeley and Charleston Counties, South Carolina were selected. The
inland study area, Kittredge, and the coastal study area, Fort Moultrie, are both USGS 7.5'
quadrangles. The first part of the research was to identify proper classification techniques that
could be used to monitor wetland areas similar to those occurring in the two study areas.
Traditionally, field surveys and aerial photography would be used to conduct such a study. While
such techniques are rigorous and provide valuable information for data analysis, they can be
extremely expensive or are unable to provide a comprehensive spatial depiction of wetland
distribution. Satellite data, as were used in this study, are relatively inexpensive to acquire. This
is especially important if frequent data are necessary (e.g., seasonal or yearly) to monitor change
detection over a long period of time. It is clearly demonstrated, in this study, that Landsat TM
data is suitable to conduct classification of the coastal wetlands around Charleston, South
Carolina. Six dates of Landsat TM imagery were analyzed and classified. Accuracy assessments
on the classification and change detection maps showed a good correlation between classified
Landsat TM data (predicted) and NAPP/NHAP aerial photo-graphy (actual). Overall accuracies
ranged from 82.91% to 92.30% depending on the classification technique used.
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C-CAP is hoping to monitor variations along the entire coastline of the United States
every 2 to 5 years, so it is important to study if significant changes can be detected over that time
period. The next phase of this research, therefore, was to test different change detection
methodologies so to observe which one would be most useful in monitoring changes in the coastal
region over a specific time period (six years: 1982-1988). It was found that post-classification
change detection logic is suitable for C-CAP if the individual dates of imagery are classified as
accurately as possible. Such logic is essential if diverse from-to classes of interest are to be
displayed. Over the six year period, a significant amount of change was detected in both the
Kittredge and Fort Moultrie study areas. The final change detection maps also demonstrated that
tidal stage is a major influence on detected variations between dates of imagery. This was
examined closely in the next part of the research.
Defined CoastWatch tidal protocol calls for MLT as preferred, 30 to 60 cm above MLT as
acceptable, and 90 cm or more above MLT as unacceptable: For accurate classification of coastal
wetlands and for proper change detection analysis, an understanding of how tidal stage affects
remotely sensed imagery is necessary. This part of the research focused on tidally-influenced
coastal wetlands, so it was limited to the Fort Moultrie study area. Different tidal heights were
modeled using a flooding algorithm, DEM, GIS, and Landsat TM data. Results of this research
indicated: (1) that an increase of 59 cm in tidal height can cause a 15% loss of information on
intertidal wetlands; (2) the CoastWatch tidal protocol should be made more rigorous, imagery
should be constrained to be acquired at tidal stages of 45 cm above MLT or less would result in
5% or less loss of wetland information when compared to images acquired near MLT; and (3) it
should be noted that mud flats can not be inventoried at tidal stages greater than 63 cm above
MLT and that a significant loss ofSpartina alterniflora occurs beyond 109 cm above MLT.
The CoastWatch program is also very interested in monitoring the possible rise in sea level
associated with global warming. The final part of the research, therefore, demonstrates the utility
of the Landsat TM data set and the high resolution DEM, constructed in the tidal research, to
predict the effect of sea level rise on the Fort Moultrie quadrangle. Using several GIS functions it
was possible to predict the effects of sea level rise on the coastal region. The impacted areas were
then overlaid on the satellite imagery to identify what land covers will be affected the most. This
study showed that coastal wetlands will be the most affected coastal feature if sea level rises.
Also demonstrated, was that Landsat TM data can be used for detecting water level changes,
using both visual interpretation and change detection techniques.
CONCLUSION
used to map bathymetry in the intertidal zone. This could be of significant importance to areas of
the globe where there are no topographic maps of the coastal zone Large spatial areas (185 x
178 km) can be mapped with just one image of Landsat TM. Thus, it is conceivable that with just
a few images, that span the tidal range (i.e., from spring low to spring high), that a topographic
This research demonstrated that tidal stage will play an important role on how coastal land
covers are classified, in particular the wetland and mud flat environments. With an increasing tidal
stage, a significant loss of information on the wetland and mud flat environments was perceived
This first became apparent in the change detection research, but was even more evident as the
tides were studied in more detail. Using a high resolution DEM and a flooding algorithm tidal
stage was simulated and found to be statistically similar to Landsat TM data. This allowed for
further analysis that revealed significant amounts of spectral information, in the coastal habitats
was being lost because of higher tidal stage. The loss of information occurred as either mixed
pixels, or wetland and mud flat environments being recognized as water. This aspect of the
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research should help in improving future remotely sensed classifications of the coastal zone
because it points out that more emphasis should be given to the stage of the tide, which is often
overlooked in remote sensing studies.
The Landsat TM near-infrared spectral band was established as a rigorous indicator of
water level. It is suggested here that TM Band 4 can be used to delineate land/water boundaries
and be map can be produced of an entire coastline's intertidal zone. Intertidal zones are one of the
most productive marine environments and are areas that are vulnerable to many environmental
hazards and natural influences. Their mapping is of primary importance in this day and age of oil
spills and sea level rise. With the cost of satellite imagery being relatively inexpensive, producing
remotely sensed intertidal bathymetry maps offers a practical alternative to undertaking a
demanding field survey, of the intertidal zone, which could take several years.
The classification and change detection techniques revealed that certain land covers in the
coastal zone can be uniquely identified using Landsat TM data, while others, despite being
spatially resolvable, could not. Understanding the reasons why certain land covers could not be
spectrally resolved is almost as important as 'correctly identifying ones that can. This is because
future classification algorithms can be designed based on a priori knowledge obtained from
studies such as this research. Knowledge of the study area, soil maps, and crop reports helped
explain why some of the land covers could not be spectrally identified as unique classes. There
was confusion between developed land features and bare/exposed soils. After consulting soil
maps of the area, it was clear that the high composition of sand in most of the region's soils
confused them with the sandy-concrete substrate found in most developed structures. Cultivated
fields were also not spectrally unique because of confusion with bare soil and woody uplands.
After reviewing several crop reports it became apparent that most of the crops in the study area
were either at the end of their growing cycle or fallow. The imagery in this research was primarily
from the winter months, thus the confusion between these classes is logical (fallow fields/bare soil;
senescing crops and "browning/yellowing" woody upland). A summer date of imagery would
probably alleviate some of the confusion between the crops and the bare soil, though it may create
other "chaos" not found in the winter scenes.
Finally, this research demonstrated the usefulness of a GIS to the field of remote sensing,
not only as a database, but as a means of modeling the coastal environment. ARC/INFO, the GIS
used in this study, allowed integration between the satellite data and other map-based ancillary
data. Using polygon overlay, a "genuine" GIS function, change detection between two classified
satellite images was performed. Accuracy assessment of the classifications and change detection
was also performed using polygon overlay GIS techniques. The construction of the DEM and the
application of the flooding algorithm was also accomplished within the GIS. The GIS allowed
comparisons to be made between the satellite data and the outputs from the flooded DEM. And
in the final stage of the research, the mapping of the different sea level rise scenarios on the
coastal wetlands also involved GIS functionality. Polygon overlay was used to identify the land
covers that would most likely be affected by sea level changes. Hectares of land cover loss, to sea
level rise, could be calculated from the GIS.
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COMMUNICATIONS AND INFORMATION MANAGEMENT:
KEYS TO PERFORMANCE IMPROVEMENT IN THE MANAGEMENT OF COASTAL
HABITATS
Ronald C. Baird
Department of Biology and Biotechnology
Worcester Polytechnic Institute
Worcester, Massachusetts 01609
(508)831-5198
Fax: (508)831-5604
EMail: rcbaird@jake.wpi.edu
ABSTRACT
New approaches to the management of coastal environments subject to increasing human
development must involve large regional areas and considerations of cos^enefit if we are to
protect the biological integrity of those habitats on a sustained basis. Critical to the success of
such approaches is sound public policy based on social consensus and scientific knowledge. In
such a milieu, environmental management agencies can considerably enhance performance
through good communication and information management. A communication plan developed by
the Gulf of Maine Regional Research Board is presented as a case study in addressing
communication management issues.
INTRODUCTION
It is anticipated that by the middle of the next decade 40 million people will be added to
the U.S. population (Kiplinger & Kiplinger, 1993), the majority of whom will reside in coastal
areas. Our national economy is expected to grow accordingly and the contribution of the coastal
margin to GNP is already considerable (King, 1992). Cumulative adverse environmental impacts
to coastal regions can also be expected to increase as the magnitude of development reaches
unprecedented dimensions (Myers, 1993). Population growth in the next decade (and beyond)
then will put immense demands on management agencies to maintain the ecological integrity of
coastal habitats on a sustained basis. Furthermore, growth in coastal development is occurring at
a time of budgetary constraint in government that renders difficult additional investments in
environmental management, research and enforcement (Baird, 1995). If we are to prevent
potential irreversible ecological consequences to coastal habitats, then our management agencies
must place a high premium on efficiency, accountability and performance. Every avenue for
performance improvement must be explored. A sound communication policy is integral to
improving performance in the resource management milieu we envision.
THE NEW MANAGEMENT MILIEU
The sheer magnitude and geographic extent of future coastal development will necessitate
changes in the way we manage these environments and these changes are already underway. The
central objective is the preservation of an acceptable level and geographic scale of coastal
ecosystem integrity and function that will insure their long term productive use (Thomson, 1994)
There are at least three themes pervading new approaches to environmental protection. One is
geo-ecosystematic management where the integrity of biological systems as a whole and their
regional extent are critical considerations (Likens, 1992; Woodley, et al., 1993; Rowe & Barnes,
1994). The second is goal-directed management where the objective is an end result or
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benchmark. For instance, a recent EPA draft document proposes as a goal that by the year
2000, 90% of the nation's estuaries will support healthy and diverse life (NEPA, 1995). The last
theme is economics-based management where the cost/benefits of regulatory policy are
considered (Coker & Richards, 1992; Hahn, 1994).
Implementing large-scale management approaches coupled with rapid coastal
development portend enormous difficulty for our institutions of management. Decisions must be
made in real time with the best information at hand. Scientific data need to get into the public
policy arena more rapidly and in an integrated form (for non-scientists). We will have to
adequately define for management purposes what is important to human and ecosystem health in
the context of tradeoffs and risk analysis. Societal values are involved and may change with time.
All of this has to be done in a relatively short period against a background of population growth,
economic development and cumulative environmental impacts (Odum, 1982; Rieser, 1992).
THE BENEFIT OF COMMUNICATIONS MANAGEMENT
Management decision-making is a politically mediated activity. Successful management
approaches must not only incorporate scientific information, but address such issues as values and
perceived benefits. Without a high degree of political consensus on environmental issues, society
may not respond adequately to insure long term environmental protection. Communication is a
necessary catalyst to successful management performance and sustained public investment in a
sound environmental protection infrastructure. Management agencies must understand and utilize
to the fullest contemporary communication and information management techniques, strategies
and technologies. We live in an information age and every day witnesses a new addition to or
improvement in the information highway. This potential for rapidly reaching large and diverse
audiences at reasonable cost may soon be virtually unlimited. The widespread access to
information has led to the breakdown of traditional media control of information and there are
literally a plethora of communication vehicles including cable TV, radio talk shows and the World
Wide Web that now influence public opinion. By understanding and utilizing these resources,
environmental managers stand to better advance their agency's agenda.
Good communications management can:
a) Shorten time between knowledge creation and public response to that knowledge.
It gets scientific information more quickly into the policy arena.
b) Improve information flow about current environmental conditions, a critical need in
future management practice.
c) Promote coordination among agencies and institutions of government. This is
essential if we hope to manage large scale systems under current fragmented
institutional jurisdictions.
d) Reinforce public policy by reducing misunderstandings, clarifying issues and better
aligning public perception with scientific fact.
e) Result in a more informed public.
f) Frame the debate, focus on the most critical issues and knowledge gaps.
g) Better articulate accountability and performance of public agencies to constituencies
that benefit from and provide support to those agencies.
h) Ultimately lead to better instruments of public policy (legislation, legal decisions,
cost effective regulation).
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A CASE STUDY
Gulf of Maine Regional Research Board - The Regional Marine Research Board Program
was established by Congress under PL 101-593. Program objectives are to develop
environmental research plans for coastal regions, identify regional research needs and promote
interaction among scientists, environmental management agencies and regional political
constituencies. The Gulf of Maine Regional Research Board (the Board) has developed a 10 year
research plan (GOM, 1995a) and is currently supporting research based on that plan (GOM,
1995b). Early on, the Board understood that, by mandate, it is primarily a service organization
with a responsibility to regional (and national) user group needs and expectations, that
information is the Board's primary product and that product has value (Lee, 1993) to management
decision-making for the Gulf of Maine. To be successful, a sound communications and
information management plan was essential. The following is a summary of how that plan was
developed and its principal elements. First, the Board made communications a formal
commitment of the organization and agreed to commit significant resources. Information
management became an integral part of planning. Communications activities were then prioritized
in accordance with mandate and budget.
The Board developed a four step process for implementing an information management
strategy, the four parts being:
a) identification of primary and secondary user groups
b) specification of the messages and information vehicles or products through which
information is conveyed
c) establishment of communication links with key users
d) periodic evaluation of the effectiveness and cost/benefit of our communications
efforts.
Figure 1 portrays the communication links developed directly through the Board's
membership. Advisory or peer review groups, such as the Board, are a powerful means of
involving critical constituencies. Note that the Board has directly represented critical federal
agencies, statehouses, legislatures, the Canadian government and academe. Through other
outside activities of its members, the Board has direct communication links with a far greater
number of critical user groups such as economic development
agencies, fisheries councils, private industry and legislative subcommittees. That is a powerful
mix of communication links with key user groups that influence management policy in the Gulf of
Maine.
Figure 2 illustrates the links through various vehicles or communications products that the
Board produces directly or commissions. A principal example is the ten year research plan
(GOM, 1995 a) that was widely circulated among sponsoring federal agencies and key
congressional committees. Workshops involving Board sponsored researchers and invited
interested constituencies have been sponsored in order to examine critical issues or review
research findings (GOM, 1995b). Pamphlets and informational literature have been created and
promulgated at modest cost through the Sea Grant communication network. The network
employs media professionals and reaches a broad audience (Figure 2). By judicious planning,
modest investment and maximum use of the board's network of contacts, information generated
by board activities rapidly, and in digested form, reaches a broad audience that collectively
influence public policy on regional environmental protection.
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Figure 3 depicts the board's approach to the management of scientific information. To
make scientific information more rapidly and readily available electronically to management
agencies, the Board explored existing distributed data base models such as DODS (Milkowski,
1995) and C-CAP (Mason & Cohen, 1995). The concept adopted (Figure 3) makes use of the
information highway and involves a central management group networked to a number of
databases maintained by various institutions, most of whom are actively creating new data
through research contracts sponsored by the Board.
CONCLUSION
In closing, we are going to have to work smarter and with less resources in the future in
protecting our valuable coastal habitats. The degree of public awareness, societal consensus and
availability of sound scientific information will largely determine how well we perform. Well-
founded communications and information management can make all the difference.
ACKNOWLEDGMENTS
The author acknowledges with pleasure the many contributions of the various members of
the Gulf of Maine Regional Marine Resource Board under the able leadership of Dr. Robert E.
Wall.
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LITERATURE CITED
Baird, R.C. 1995. Toward new paradigms in coastal resource management: linkages and
institutional effectiveness. Estuaries, (in press).
Coker A. and C. Richards (eds.). 1992. Valuing the Environment: Economic Approaches
to Environmental Evaluation. Belhaven Press, Boca Raton, Florida. 192 p.
GOM, 1995a Gulf of Maine Research Proposal. Gulf of Maine Regional Marine Research
Program, University of Maine, Orono, Maine. 15 May 1995. 599 p.
GOM, 1995b. Report on Research Program. Gulf of Maine Regional Marine Research
Program, University of Maine, Orono, Maine. February 1995. 125 p.
Hahn, R.W. 1994. United States environmental policy; past, present and future. Natural
Resources Journal 34:305-348.
King, L.R. 1992. Ocean and coastal management in the United States: need to incorporate
local, state and regional, perspectives, p. 54-55. In B.
Cicin-Sain (ed.), Ocean Governance: A New Vision. Ocean Governance Study Group,
Center for Marine Policy. University of Delaware, Newark.
Kiplinger, A. and K. Kiplinger. 1993. The Kiplinger Washington Letter. December 22.
Lee, K.N. 1993. Compass and Gyroscope: Integrating Science and Politics for the
Environment. Island Press, Washington, 243 p.
Likens, G.E. 1992. The Ecosystem Approach: Its Use and Abuse. Volume 3. Ecology
Institute. Oldendorf/Luhe, Germany. 166 p.
Mason, C. and R. Cohen 1995. National Oceanographic and Atmospheric Administration's
Center for Coastal Ecosystem Health. American Institute of Fisheries Research
Biologists Briefs. 24 (2):4-6.
Milkowski, G. 1995. DODS: providing direct access to distributed research data resources.
Oceanography 8:26-29.
Myers, N. 1993. The question of linkages in environment and development. Bioscience
43:302-310.
NEPA. 1995. Proposed Environmental Goals for America with Benchmarks for the Year
2005. Summary Draft for Agencies' Review. United States Environmental
Protection Agency-230-D-95-001. Washington. 7p.
Odum, E. 1982. Environmental degradation and the tyranny of small decisions. Bioscience
32:728-734.
Rieser, A. 1992. Assessing cumulative impacts, p. 39-42. In. B. Cicin-Sain (ed.). Ocean
Governance: A New Vision. Ocean Governance Study Group, Center for Marine
Policy. University of Delaware, Newark.
Rowe, J.S. andB.V Barnes. 1994. Geo-ecosystems and bio-ecosystems. Bulletin
Ecological Society of America 75(1):40-41.
Thomson, K.S. 1994. No easy answers. American Scientist 82(3):212-215.
Woodley, S., J. Kay and G. Francis (eds.). 1993. Ecological Integrity and the Management
of Ecosystems. St. Lucie Press, Delray Beach, Florida. 228 p.
12
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COM
USER Communications
Figure 1. Overview of communications links
through members of Gulf of Maine Regional
Marine Research Board. States represented
are Maine, Massachusetts and New
Hampshire. Agencies appointing members
are listed in center circle.
COM
USER Communications
(Products)
PRODUCTS
Reports
So Publications
Wbrtuhops
Research Plant
Pmi Releases
Summaries
Figure 2. Informational "products" produced
by the Regional Marine Research Board.
Major user groups identified for receipt of
those products appear in outer rectangles.
COM
USER Communications
Environmental DATA and Information
Management System
Figure 3. Schematic of Regional Research
Board's environmental data and information
management system plan. Organizations on
outer ring constitute the network with more
than one entity per state. NOAA satellite data
is an input, other users can access information
through Internet.
13
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AN ECOSYSTEM MODEL: PREDICTION AND REGULATION
A.Y. Benilov and T G. McKee Jr.
Davidson Laboratory
Stevens Institute of Technology
Hoboken, NJ 07030
ABSTRACT
The ecosystem model proposed is simple enough for analytical study and simultaneously
reflects the basic features of natural ecosystems. The dynamic and thermodynamic description of
the model are presented. The ecosystem model has several parameters which control its dynamic
features and equilibrium state. The stability analysis shows that an external impact dramatically
changes the equilibrium state of the ecosystem and can produce irreversible destructive changes in
it. In the framework of the given approach, analysis of the dynamic features of the model is done,
and examples of prediction and regulation are presented. The ranges of ecosystem's parameters
which produce minimal damages from external impacts leads to a successful management by
generating optimal regulations.
INTRODUCTION: REQUIREMENTS TO A MODEL
At the present time, methods of mathematical modeling are broadly used to suggest
solutions to different kinds of ecological problems. Some general principles of ecological system
modeling are developed and described in numerous early and recent publications [1-19]. The
study of the oceanic ecosystem has become an important and quickly developing direction of sea
biology [10, 13, 21] The complexity of ecological systems due to the huge number of trophic
levels and the complex structure of their interactions with each other and with the surrounding
environment, in most cases, only allows for numerical simulations by the existing models [5, 7, 8,
10, 12, 16, 20, 21]. For instance, an existing literature model may be considered the simplest of
ecological models [22], however, may still be so complex, that some qualitative and quantitative
conclusions regarding features of the ecosystem behavior, as it is influenced by changes in its
biological characteristics and environmental parameters, have not been found so far: For that
reason, it is difficult to apply these models when attempting to make more consistent regulatory
and management decisions.
In light of this, it appears to be necessary to build and develop a simple model. The
ecosystem model proposed is simple enough for analytical study and simultaneously reflects the
basic features of natural ecosystems, which are as follows:
1 Any natural ecosystem consists of a biotic component (living thing), an abiotic organic
component (nonliving), and an inorganic (biogenic) component [23, 24].
2. For all ecosystems, there is a substance cycle [23, 24], i.e. the transformation of
mineral nutrition (abiotic inorganic component) into a biomass of the biotic component
as a result of a photosynthetic reaction and the growth of the abiotic organic
component due to the vital activity and the mineralization of the abiotic organic
closing of the substance cycle.
3. The biotic component biomass increases if the nutrition (biogenic) is sufficient and
decreases for opposite case.
4. If the space range occupied by the ecosystem does not contain inner and surface
sources for all of its components, then the conservation law of substance is carried out
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for the entire ecosystem [23, 25].
5. From an energetic point of view, the natural ecosystems are open because the
processes of the biomass growth occur due to the energy flux of sun radiation, and the
conservation law of energy is carried out for the entire ecosystem [6, 10, 13, 23,
26-28].
6. As any closed ecosystem having a steady energy flux flowing through it, the studied
system produces a self-regulating mechanism and develops to a stable state [5].
The enumerated features of the ecosystem are well known and, apparently, are the
minimum features which must be fulfilled by a model description of a natural ecosystem. Thus, the
simplest ecosystem model have to include at least three components, and their, interactions with
each other provide execution of the conditions (2)-(6). In the framework of the given approach,
analysis of the dynamic features of the model [11] is done, and examples of prediction and
regulation are presented.
THE MODEL EQUATIONS AND ITS FEATURES
Let us consider the ecosystem with a substance density W, distributed between its
components at some manner, and occupying in the space (x,y,z) volume V, which does not have
changes in time t.
Performing condition (1), the density W can be represented by the sum of living organic
component, M, mineral nutrition (biogenic component), B, and nonliving organic component
(detritus), G. The transfer equation of the aquatic ecosystem substance, W, can be written in the
most general form [11].
It is assumed, that inside the region, occupied by the ecosystem, the substance W is not
produced and does not vanish, i.e., there are no sources and sinks of the substance W.
We also consider that there are no fluid flow and no mass fluxes into any of the
components through the boundary of region occupied by the ecosystem. It follows under the
given assumptions, that the whole supply of ecosystem substance does not change in time. It
means that requirement (4) is fulfilled. At the same time, the local temporal and spatial variability,
caused by nonuniformities of illumination (which is responsible for photosynthesis) and variability
of hydrophysical fields of fluid, may exist and even may be
significant.
The Equation for W is found by summation of the transfer equations for components M, B
and G, which have similar forms. Therefore, in the case of spatial uniformity of biological and
hydrophysical fields, to simplify the problem, the equations for the components M, B and G
reduce to evolutionary equations, where the right hand sides produce the substance transfer
through the all components of the system.
The satisfaction of requirement (2) involves that the rates of productions and losses in all
the ecosystem components are not independent quantities but must have a form of uniform linear
constraints [11] which produce a closed substance flow through all the ecosystem components.
As a result, the closure of the evolutionary equations, which governs the ecosystem components,
is done by specifying the respective sources and sinks. Due to mass conservation, only half of
them are really needed.
In the given case of the three-components-ecosystem, the rate of losses, or rate of
mineralization of the abiotic organic component G, can be approximately defined by experimental
data [29], which shows this quantity can be expressed as a uniform linear function of G.
Using some assumptions based on the known results [6, 27, 32], the rate of mineral
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nutrition expenditure, caused by the photosynthetic reaction, is derived in a form of second order
reaction (30, 31] which produces transformation of the abiotic inorganic component (mineral
nutrition) into the biomass of the biotic organic component. This form of the photosynthetic
reaction is well known as the Michaelis-Menten equation [4, 15].
The final closure of the model equations is done by the derivation of an analytic expression
for the rate of total change of the biotic organic component. This quantity is taken as a uniform
linear function of the biotic organic component M and a second degree polynomial of the abiotic
inorganic component B As a result of the given approach, there must be a value B = {B sub{ 1}},
a critical value of the abiotic inorganic component B: component M must decrease when
component B is in the range 0 =< B < {B sub{ 1}}, and it must grow for {B sub{ 1}} < B < W.
Thus, the biotic component biomass increases if the nutrition (biogenic) is sufficient and decreases
for opposite case, and the condition (3) is fulfilled. It has to be mentioned, that there is an
asymptotic case in which the equation for M reduces to the well-known equation for a predator of
the Volterra's predator-prey model.
ENERGY TRANSFORMATION
The given model has following energetic features. Let us denote that E is a total energy of
the ecosystem, Qe is the sun energy influx to the ecosystem spent for the photosynthetic reaction,
D is energy dissipation in the system. Then, the total ecosystem energy changes rate is defined by
difference between the energy influx Qe and dissipation D. In accordance with [23, 26, 33, 34],
the energy E can be considered as a function of components M and G, i.e. E = E(M,G). This
means that the changes of the system total energy E occurs due to changes of the organic material
contained in the system.
The next step is a definition of an energy U, which corresponds to the biogenic substance
because the change of mass of organic substance occurs along with a change of biogenic
component and energy E. The energy U is such energy which would be spent to transform the
biogenic component into the organic material. It follows from given definition that the
conservative quantity is the sum of E and U, E + U = E* = const, where energy E* corresponds
to the total amount of the ecosystem substance W. It also follows from definition of the energy
U, that this energy can be considered as a function of B, and, consequently, the change dU can be
represented by the change of B.
A further analysis, based on these notations, shows that dissipation chiefly occurs due to
the mineralization of the organic material. When the characteristic time of the photosynthesis
tends to infinity ({tau sub{b}} ->{infinity}), meaning that the energy influx Qe -> 0, all the
substances of ecosystem accumulate irreversibly in the component B confirming physical intuition.
The expressions found for dissipation, D, and solar energy influx, Qe, defines the energy
flow through the ecosystem in the following form: the energy influx to the system is defined by
its the photosynthetic reaction efficiency, and the dissipation is caused by the energy released
during the decomposition of the organic material Thus, the given ecosystem is dissipative and can
only exist without decaying when the energy influx comes in the system, and so, from the
energetic point of view, the ecosystem is an open system, and then the condition (5) is fulfilled
The general structure of the model, in accordance the requirements (l)-(6) and given
formalization, is illustrated on Figure 1. The external impacts, such as climate, weather, and
human impacts affect each ecosystem component producing variability of the ecosystem
parameters, {tau sub{b}}, {tau sub{s}}, {tau subjg}}, and {chi}. The regulations and control of
the ecosystem behavior, which are a part of the human impacts, are selected to provide a given
optimal ecosystem behavior reducing natural and artificial destructive effects. Defining them by a
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model analysis may take the following form:
1. The equilibrium state of the ecosystem, defined by the natural values of the parameters
{tau sub{b}}, (tau sub{s}}, {tau sub{g}}, and {chi}, may be taken as its base state.
2. The regulations give the ranges of ecosystem's parameters and its component values,
which are based on an obtainable state that suffers from external impacts.
3. The control is a management process governing the ecosystem parameters to keep the
system in the ranges specified by the regulations.
Below, to simplify the analysis, the external impact is introduced only in the term which
governs the photosynthetic reaction. As a first step of the study, it is necessary to figure out
differences brought in the equilibrium state by the external parameter.
STABILITY ANALYSIS AND NUMERICAL RESULTS
The stability analysis of the model equations, written in a dimensionless form, (M,B,G,{B
sub{ 1} })-> (m,b,g, (beta sub{ 1}}), is carried out for the case 2 =< {tau sub{s} }/{tau sub{b}}
<{infinity}, where photosynthesis is near a maximum. The system of equations has two stationary
solutions.
One of them is trivial, b=l,m = g = 0, and means that the whole substance of ecosystem
is accumulated in the biogenic component. A stability analysis shows that the given steady
solution is unstable. Therefore the self-creation of biotic component can not occur in the given
model, but for any small initial disturbance of the biotic organic material, it will increase in time.
The second steady solution, m= {mu sub{l}}({beta sub{l}}, {gemma}, {chi}), b= {beta
sub{l}}({gemmasub{s}}), g= {zetasub{l}}({betasub{l}},{gemma}, {chi}) (see Figure 1), is
stable. The results of numerical calculations indicate that the ecosystem reaches this state from
any initial values of its components excluding the unique initial condition m(0) = 0, and it means
that condition (6) of Section 1 is fulfilled. Thus, the given ecosystem model performs all
requirements enumerated in Section 1.
The biological parameters of the system {tau sub{b}}, {tau sub{s}}, {tau sub{g}}, and
{chi} completely define the second stationary solution which can be reckoned as an equilibrium
state because of its stability. Basing on the given parameter values, the ecosystem may be
classified as follows:
1. The ecosystem does not possess an oscillatory regime, and small initial disturbances of
the system exponentially degenerate.
2. The ecosystem does not possess an oscillatory regime, small initial disturbances grow
linearly and then decay exponentially.
3. The ecosystem possesses an oscillatory regime where the amplitude may decay with
time. The eigenfrequency {omega} is shown as the oscillatory factor as a function of
{beta sub{ 1}} and {gemma} in Figure 2d.
In the case without an external impact and the component M is much less then its
equilibrium value, the biotic component development for {gemma sub{s}} = 0.09, {chi} = 0.99
and different values {gemma} is shown in Figure 2a. One can see that all types of ecosystems,
characterized by {gemma}, after an initial evolution stage take the equilibrium steady state, which
is shown in Figures 2b and 2c as surfaces of biotic component and abiotic organic component
versus {beta sub{l}} and {gemma}. The stability of the steady equilibrium state is illustrated with
17
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Figures 2d = 2e.
The maximum equilibrium values of the component G can be observed when the
parameter {gemma sub{s}} is from the range 0 =< {gemma sub{s}} =< 1/3. Hence, the absorbed
solar energy flux is proportional with the nonliving component, and it takes the maximum value
{qsub{l}} = {qsub{lmax}} for {beta sub{l}} = {beta sub{lmax}}. The quantity
{q sub{1 max}} increases with the growth of {gemma} and reaches a limit value.
It follows from the given analysis, from the energetic point of view, that the ecosystems
with large values of the mineralization time, {gemma} « 1, are systems with small energetic
capacity, since the substance circulation goes through the systems slowly due to a significant
substance transformation delay occurring in the nonliving component. When the substance
transformation goes fast enough, {gemma} » 1, then the fraction of G in W is small but the
energetic capacity of such ecosystems is maximal because they absorb most of the energy influx.
The external impact factor dramatically increases the sensitivity of the equilibrium state to
the parameters, in particular {beta sub{ 1}} the inorganic component. Figure 3a shows the
equilibrium value of the inorganic component against {beta sub{ 1}} and the external impact
factor. It can be seen that there is an area of values of {beta sub{ 1}} and external impact factor
where the ecosystems do not have an equilibrium state and will degenerate. Figure 3b shows the
phase portrait of solutions flow when the external impact factor q is greater than its critical value
{q sub{cr}}. In this case, the ecosystem has a stable equilibrium state (cross) and two unstable
steady states (first one is shown by circle, second one corresponds the trivial solution m = 0,
b = 1). Figure 3c demonstrates the phase portrait of solutions flow when the external impact
factor q is less than its critical value {q sub{cr}}, and when the ecosystem has a stable equilibrium
state only in the point m = 0, b = 1. Figures 4a - 4b demonstrate this kind of ecosystem behavior
for high and low initial values of the biotic component. In this case, the external impact factor is
less then its critical value, and the ecosystem has unique steady state when the biotic component
completely degenerates. The given example can be reckoned as a sample of unsuccessful control.
To produce successful control the ranges of allowed values of the external impact factor and the
initial conditions have to be reduced in accordance with the stability analysis for the case of
external impact The result of successful control which was produced by regulations derived from
the equilibrium state with and without an external impact are shown in Figures 5a - 5b. The
numerical calculations were carried out for a random external impact factor. In the first case,
Figure 5a, corresponds to the situation of control with a risk, i.e., the ecosystem can be found,
with small value of probability, in a dangerous state because of a random external impact factor.
It happened with the ecosystem which had {gemma}= 0.18. Figure 5b shows the result of control
with no risk. Thus, the successfully developing ecosystems come to their equilibrium states and
fluctuate near them.
Using the external parameter, the effect of the annual cycle of solar radiation along with a
random noise, which simulate weather oscillations, can be studied by the model. Figure 6 shows
the annual cycle of biotic component under a random external impact. The given example was
produced by regulations and control with no risk to provide an optimal behavior of the ecosystem
to minimize damages. This type of model can be generalized to a multicomponent form of
ecosystem.
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CONCLUSION
1. The ecosystem model fulfills the basic features of natural ecosystem, and without external
impacts, it evolves into a stable equilibrium state.
2. The ecosystem model has several parameters which control its dynamic features and
equilibrium state.
3. An external impact dramatically changes dynamic features and equilibrium state of the
ecosystem and can produce irreversible destructive changes in it.
4. The ranges of ecosystem's parameters which produce minimal damages from external
impacts leads to a successful management by generating optimal regulations.
5. The ecosystem model can be employed for strategic planning of natural ecosystem
development and provide a prediction of the consequences.
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PP
32. Jamart Bruno M., Winter Donald F., and Bause Karl, 1979, Sensitivity Analysis of
Mathematical Model of Phytoplankton Growth and Nutrient Distribution in the Pacific
Ocean off the North Western U.S. Coast, Journal of Plankton Research, v. 1, No 3, pp.
267 - 290.
33. Vinogradov M.E., Krapivin V.F., Menshutkin V V., Fleishman B.S., and Shushkina E.A,
1973, Mathematical Model of the Pelagic Ecosystem Functioning in the Tropical Regions
of the Ocean, Moscow, Oceanography, v. 13, No 5, pp. 852 - 866.
34. Vinberg G.G., 1962, Energy Principles for the Study of Ecosystems Trophic Interactions
and Productions, Zoological Journal, v. 41, No 11.
20
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THE MODEL DESCRIPTION
, . mineral nutrition
1.;" abiotic inorglrt&i^
abiotic organic coraponet
Figure 1 (a). The ecosystem model, upper part.
-------
K>
to
Climate
external impacts = -^ Weather
Jluman impacts
IB characteristic time of the photosynthetic reaction
T5 characteristic life time for the starvation (b —> 0)
ig characteristic time of the mineralization
X fraction of the full substance Flux from m to g
Y =
Figure 1 (b). The ecosystem model diagram, lower part.
-------
EQUILIBRIUM STATE AND STABILITY ANALYSIS VITHODT AW EXTERNAL MPACT
U)
0.2
(a)
200
0.15
0.05
tr
£?--- -
-------
(b)
K>
EQDILIBRTnif
Figure 2 (b). Equilibrium state of biotic component versus {beta sub{l}} and {gemma}.
-------
(c)
K>
0
0.5
EQUILIBRIUM STATE
Figure 2 (c). Equilibrium state of abiotic organic component versus {beta sub{l}} and {gemma}.
-------
(d)
to
Figure 2 (d). Oscillatory factor in the vicinity of the equilibrium state versus {beta sub{l}} and {gemma}.
-------
0.5 -
N)
a.
M
H
0
(e)
0.5
Figure 2 (e). Exponential decay in the vicinity of the equilibrium state versus {beta sub{l}} and {gemma}.
-------
EQUILIBRIUM STATE AND STABILITY ANALYSIS VITH AN EITERNAL IMPACT
Inorganic Component
(a)
to
00
External Impact Factor
Figure 3 (a). Equilibrium state of the inorganic component versus {beta sub{l}} and an external impact factor.
-------
(b)
b1=0.1 qcr=0.575 q=0.7 k=0.99 c=0.05
EQUTLffiRIUM POINT
Figure 3 (b). Phase portrait of the solutions flow when the external impact factor q is greater
than its critical value {q sub{cr}}, and when the ecosystem has a stable equilibrium state (cross)
and two unstable steady states (first one is shown by circle, second one corresponds the trivial
solution m =0, b = 1).
29
-------
(c)
b1=0.1 qcr=0.575q=0.1 k=0.99c=0.05
NO EQUILIBRIUM POINT AND DEGENERATION OF THE BIOTIC COMPONENT
Figure 3 (c). Phase portrait of the solutions flow when the external impact factor q is less than
its critical value {q sub{cr}}, and when the ecosystem has a stable equilibrium state only in the
point m=0, b=l.
30
-------
In this case the biotic component completely dies.
u>
oa
50
(a)
0.2
0.15
0.1
100
150
200
DAY
250
0.05
300
350
Figure 4. Two examples of unsuccessful control of the ecosystem which are under an external impact.
(a). High level of initial values of the biotic component.
-------
u>
S)
5
0.2
50
Figure 4 Two examples of unsuccessful control of the ecosystem which are under an external impact.
(b) Low level of initial values of the biotic component.
-------
In this case the biotic component reaches an equilibrium state.
u>
E-.
O
I—I
aa
50
0.15
0.1
0.05
350
Figure 5. The examples of successful control of the ecosystem which are under a random external i
(a). Control with risk.
0.2
impact.
-------
(b)
1000
500
DAY
Figure 5. The examples of successful control of the ecosystem which are under a random external impact.
(b).Control with no risk.
-------
THE ANNDAL CYCLE OF BIOTIC COMPONENT UNDER A RANDOM EXTERNAL IMPACT
700
0.1
0.05
Figure 6.
-------
ENHANCING SHALLOW WATER HABITAT THROUGH SHORELINE BLUFF
STABILIZATION (1995)
Joseph A. Berg, Jr. and Edward W. Morgereth, Jr.
EA Engineering, Science and Technology, Inc.
11019 McCormick Road
Hunt Valley, Maryland 21031
Peter Kotulak
Moffitt and Nichol
Baltimore, Maryland
INTRODUCTION
The erosion of shoreline is known to be important to the form and function of adjacent
estuarine shallow water habitat (ACOE 1984; Duane et al., 1975). Input of sediment and
associated plant material (e.g., trees), can be a necessary source of allochthonous material for the
maintenance of food web support (ACOE, 1990). Alternatively, the input of excessive amounts
of these materials can lead to the degradation of the shallow water habitat currently in equilibrium
with "normal" sediment loads (Hill et al., 1983; ACOE 1990). The yield of sediment from
shoreline bluff erosion can be large and episodic when the height of the bluff is great and the face
of the bluff nearly vertical or with a negative slope (ACOE, 1990). Even under moderate
conditions where bluff height may be 5 to 15-ft, a single storm can result in the erosion of tons of
sediment per running foot of bluff (Wang et al., 1982). This material may be entrained in currents
and transported over a large area, or the material may slump in place, burying the shallow water
habitat in the vicinity of the bluff (ACOE, 1984). The erosion of bluff areas may be part of a
natural process, but more commonly, bluff erosion in the tributaries of the Chesapeake Bay is
exacerbated by anthropogenic factors such as boat wakes (ACOE, 1984; Broom et al., 1981).
Efforts to stabilize existing shoreline erosion may be initiated with the goal of protecting fastland,
or less frequently, with the goal of protecting aquatic resources.
In general, minimizing erosion of any type is viewed as an improvement, particularly when
the path of eroded sediment into water is as obvious as in shoreline erosion circumstances.
However, shoreline stabilization can result in a significant modification of the shallow water
habitat to ensure a high degree of certainty that erosion will be successfully reduced or eliminated
(ACOE, 1990; Wang et al., 1982). Examples of typical "engineered" and guaranteed solutions
are considered structural, and include bulkheaded shoreline; boulder, rip-rap, or gabion
revetments; and grading and filling along the shoreline to "soften" the angle of repose. A
common practice for bluff stabilization consists of dumping erosion resistant materials down the
face of the bluff (e.g., concrete rubble, tree stumps, building debris). The use of beach and marsh
grass plantings have been advocated as a non-structural solution to stabilizing areas of eroding
shoreline (Knutson, 1977). Current best management practices recognize that vegetation
plantings on their own are not usually effective at controlling shoreline erosion, but in
combination with selected structural methods, they do contribute to sediment trapping and
shallow water habitat value (Sharp et al., undated).
As a result of the different goals and approaches to shoreline stabilization, there is a need
to evaluate the effects of shoreline erosion on the resource, to evaluate the approaches proposed
to control the erosion, and to evaluate the effect approaches to erosion control have on the
shallow water habitat present.
36
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SITE DESCRIPTION
The specific application of bluff stabilization technologies described in this paper was
evaluated for a forested bluff area approximately 200-ft long with a maximum height of
approximately 15-ft. The bluff is located in Sue Creek, a sheltered cove of Middle River, a
Baltimore-area tributary to Chesapeake Bay (Figure 1). Water depth in the project vicinity
ranged from 4 to 7 ft, with a mean depth of 5-ft. This area is used intensively for recreational
boating. The fetch at this location ranges from approximately 700-ft to 4500-ft, so opportunities
for wind-driven wave formation are present. However, boat wake-wave formation is thought to
be a more significant factor in shoreline erosion in this cove area.
METHOD
A review of technical literature and phone conversations with Federal, State, and County
resource management personnel were conducted to collect current information on techniques and
considerations for stabilization of eroding bluffs. Shoreline stabilization and erosion control
methodologies are typically grouped as either structural or non-structural. Components of these
two methods can be combined to achieve the desired shoreline stabilization goal and enhance
adjacent aquatic and terrestrial habitats (Allen, 1990 & 1991). A description of the most common
structural and non-structural methodologies are provided below.
There are several types of structural stabilization. The most common are bulkheads,
revetments, breakwaters, and groins. In addition to these general types of structures, more
application-specific structures may include sills, basket cages, cut and fill, and others. These
structures can be made of a variety of materials; the most common include wood, sheet metals
(steel and aluminum), loose rock (riprap), caged rock (gabions), and concrete. Bulkheads work
by presenting a physical barrier to erosion by separating the erodible material from the action of
the water. While bulkheading is an effective method for preventing further shoreline erosion, it
has several disadvantages. First, installation of bulkheads tends to encourage toe scouring at their
bases caused by newly reflected wave energies (ACOE, 1984). Secondly, bulkheading does not
provide intertidal zone habitat typical of normal beach areas. Additionally, timber bulkheading is
typically an expensive form of shoreline stabilization requiring periodic maintenance and eventual
replacement with a projected life of 25 to 40 years (ACOE, 1990).
Revetments function in a fashion similar to bulkheads, i.e., armoring the toe of this eroding
bluff Terracing involves the cut and fill of the bluff face into a series of shorter horizontal and
vertical "steps". This approach typically requires cutting trees and significant grading. Terracing
usually requires protecting the toe of the slope with gabions or rip-rap. Alternatively,
breakwaters work by dissipating wave energy, reducing erosive action. Additionally, the
dissipation of wave energy causes sediment to drop out of the water column behind the
breakwater, eventually accumulating to form a bar area.
Vegetative planting for erosion control is a cost-efficient alternative to structural shoreline
stabilization. A variety of vegetation is available for planting bluffs, steeply sloped banks,
intertidal areas, beaches, and shallow-water areas. Vegetative stabilization works because plant
roots and rhizomes form a fibrous network throughout the substrate (soil, sand, cobble, etc.)
which helps to hold soil in place against wind and waves (SCS, 1983). The above-ground portion
of vegetation protects the shoreline by reducing wind and wave energy before it hits the substrate,
and by acting as a baffle, causing suspended sediment to fall out of the water column (Tainter,
1982). Vegetation systems are dynamic and will grow through accredited (deposited) sediments
37
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to build up the shoreline (beach) over time. Unlike structural stabilization approaches, which
must be periodically repaired or replaced, vegetative systems are generally self-maintaining, and
can often repair themselves of minor damage without costly replacements (Salvo, 1988). In
addition to shoreline stabilization benefits, vegetative plantings may also provide aesthetic,
habitat, and water quality benefits. 'However, use of vegetation for shoreline stabilization usually
is not sufficient by itself because conditions must be favorable for plant growth, and steep and
eroding shorelines are rarely favorable for growth (ACOE, 1984). In addition, selection of plant
stock should be closely matched to the tolerance/requirement ranges of the plant species and the
microenvironment present at the site. In areas of high disturbance from waves and boat wakes,
such as those at the project site, vegetative stabilization can be combined with structural
stabilizing elements to improve survival and establishment of the vegetation (Tainter, 1982).
The most effective methods of shoreline stabilization involve a combination of both
structural and non-structural measures (ACOE, 1984). For example, the establishment of an off-
shore breakwater to dissipate wave energy combined with a beach planting to stabilize sediment
and enhance shallow water habitat. Breakwaters are typically constructed using stone piles or
cabled logs. Occasionally, low profile bulkhead walls are used to achieve the breakwater effect.
The intertidal area is then planted in marsh vegetation (e.g., smooth cordgrass) and additional
plantings of trees and shrubs can be used on the beach, bluff toe, or slope depending on site
conditions and selected vegetation (SCS, 1983).
Based on our review of the literature and information contained in Table 1, a floating tree
breakwater in combination with a shoreline marsh planting and vegetative stabilization of the bluff
face with woody vines was identified as the preferred design (Hales, 1981; Grey & Leiser, 1981).
However, this design, particularly the use of trees in a floating breakwater, was not preferred by
the regulatory agencies or the property owner. The basis for their position was a concern that
trees would not persist, maintenance would be required, and maintenance is not a reliable design
feature. This position is not validated in this paper, but since the purpose of the paper is to
describe a successful action, we will not linger over the merits of floating tree breakwaters. As a
result, the floating tree breakwater concept was replaced with the second-best option identified, a
rock reef breakwater with bluff and marsh plantings (Fulford, 1985).
DESIGN CHARACTERISTICS
An estimate of water level changes, resulting from storms, tidal fluctuations, wave action
and their combined occurrence, is necessary for proper design of the rock reef structure. The
process of determining the design water elevation is complex, incorporating variables such as
wind and water interaction, atmospheric pressure, topography and bathymetry. Winds cause the
greatest change to water level elevation by acting as a horizontal force on the water surface. This
force consists of two components, a pressure differential and a shear, that combine to create the
total force. The wind force that would produce the greatest water level change at the proposed
breakwater location occurs during a hurricane event. For this project, the design windspeed uses
historical hurricane data provided in the Shore Protection Manual (USAGE, 1984). The estimate
of the rise above normal water level resulting from a hurricane consists of the complex interaction
of parameters including momentum, Coriolis force, surface slope, wind stress, bottom stress,
rainfall rate, astronomical tide potential and atmospheric pressure reduction. Astronomical tide,
wind stress and atmospheric pressure are considered to be the major contributors to water level
rise at the site.
From the Shore Protection Manual (USAGE, 1984), empirical data is provided for storm
surge observations made in three locations in the Chesapeake Bay region: Baltimore, Annapolis
38
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and Solomons Island. Average yearly highest water levels measured above mean high water
(MHW) ranged from 2.0 ft to 2.3 ft (mean = 2.2 ft). Extreme high water level above MHW
ranged from 3.4 ft to 6.7 ft (mean = 5.2 ft). The calculated watc level rise of 2.5 ft due to
atmospheric pressure drop is slightly greater than the mean of the average yearly highest for the
bay region. As the purpose of the breakwater design is to minimize erosion of the bank due to
typical storm events and waves generated from boat traffic in Sue Creek, the design storm surge
height is chosen to be 2.5 ft.
The mean tidal range for the site is reported to be 1.2 ft. The spring tidal range is reported
to be 1.4 ft. A record of observed water level data for the study area has been obtained from the
study conducted by EA for the period of 4 May 1993 to 3 June 1993. For this period, the mean
tidal range was observed to be 1.28 ft. To determine significant wave height on the breakwater,
wind data and longest fetch shallow-water wave forecasting were used. Windspeed and duration
are assumed to blow over the defined fetch area. The longest fetch is equal to 4500 ft, and
traverses the length of Sue Creek from a westerly direction. Significant wave height is defined as
the average height of the one-third highest waves of a given wave group. Equations have been
developed to calculate significant wave height and period, from which significant wave height
forecasting curves have been produced. From these curves it can be determined that for our
design windspeed of 100 mi/hr blowing over a fetch of 4500 ft, the significant wave height H, is
2.5 ft. Wave setup is defined as the super-elevation of mean water level caused by wave action
alone. It is a phenomenon where an equilibrium water level is established through the action of
many waves over a sufficient period of time. The Shore Protection Manual (USAGE, 1984)
provides curves that allow one to predict wave setup using design values for significant wave
height, period and beach slope.
From these calculations, it can be concluded that in order to cause the design wave to
break at the proposed wave height, the crest of the breakwater must be less than 3.2 ft below the
water surface under the design conditions. The water surface level for these conditions is 4.4 ft
above MLW. The design crest elevation will then be at least 1.2 ft above MLW. The water depth
at the structure is 2 ft at MLW. A breakwater height of 3 to 4 ft will be required. The size of the
primary cover layer of stone was calculated using Hudson's Formula (USAGE, 1984).
Calculations for the primary cover layer determine the weight of the individual armor stones to be
177 Ib. This size is considered the 50 percent size (W^) of graded rock to be used for
construction
IMPLEMENTATION
1976) necessary for the development of a marsh capable of delivering a sediment trapping
function, and the growth of woody vine cover over the face of the bluff.
At the time of the planting, more than 1-ft of fine sediment had accumulated between the
breakwater and the bluff, supporting the beach building capability of the breakwater. The bluff
continues to be subject to small scale face erosion due to precipitation, freeze-thaw, and minor toe
of slope water contact. However, the frequency of major slumping resulting from aggressive wave
attack at the toe of the slope has been reduced though the reduction of wave energy resulting from
the reduction in mean and maximum wave height Over time, the bluff will experience even greater
reduction.
As a result of this analysis and design, a 300-ft long continuous rock reef breakwater with
low tide "windows" was constructed 50-ft off the eroding bluff area during the fall of 1994. The
breakwater is submerged at high tide, so navigation warning piles have been included in the
breakwater. The low tide "windows" enhance communication of tidal waters between the area
39
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behind the breakwater and the remainder of the estuary. The continuous nature of the breakwater
provides a greater measure of erosion reduction at the scale of this project then the more common
interrupted breakwater used further "offshore."
The following spring of 1995, the narrow beach area was planted with 600 Spartina
alterniflora in the zone from the high-tide line to the mid-tide line, 500 Spartina patens plants
were planted above the high-tide line to the toe of the bluff and 300 Scirpus pugens (bullrush)
were planted immediately below the S. alterniflora. In addition, 375 Parthenocissus uinquefolia
(Virginia creeper) were planted on 2-ft centers in the face of the bluff. Into each of the planting
holes, 1 oz of a slow release fertilizer was placed to support the vigorous growth (Garbish et al.,
1975; Woodhouse et al.,
s in erosion as a result of beach building behind the breakwater, increased marsh vegetation
density, trapping of additional sediment which will act as "soft" armoring at the toe of the slope,
and the penetration of woody vine roots throughout the face of the bluff, binding sediment with
root material and making the existing bluff surface more resistant to erosion.
This design and implementation of this project was not based on the goal of eliminating
shoreline erosion, but was instead based on reducing the rate of bluff erosion. Prior to the
shoreline stabilization measures described here, a single storm might result in the erosion of
several tons of sediment and two or more trees. The property owner reported 2-ft of erosion per
year along the face of the bluff. With these stabilization measures in place, we do not expect the
loss of additional trees or a measurable recession of the bluff face in the next few years under
normal weather circumstances. However, even if major storms impact directly on the bluff, we
are confident that erosion will be reduced relative to the unprotected condition. Furthermore, if
erosion does occur, we expect the living components of this stabilization approach to "repair"
themselves and continue to contribute to the reduction in bluff erosion.
40
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LITERATURE CITED
Allen, H.H. 1990. Biotechnical Reservoir Shoreline Stabilization. Wildlife Resource Notes
Information Exchange Bulletin, Vol. 8, No. 1. USA Engineers Waterways Expt. Station,
Vicksburg. 31 March.
Allen, H.H. 1991. Biotechnical Shoreline Stabilization: Update Report. Wildlife Resource
Notes Information Exchange Bulletin, Vol. 9, No. 1. U.S. Army Engineers
Waterways Expt. Station, Vicksburg. 1 November.
Belcher, C.R. 1988. Planting Guide: Bare-rooted Saltmeadow Cordgrass for Tidal Bank
Stabilization. U.S.D.A. Soil Conservation Service, Somerset, New Jersey.
Broome, S.W., E.D. Seneca and W.W. Woodhouse. 1981. Planting marsh grasses for erosion
control. University of North Carolina. Sea Grant Publication 81-09. 12pp.
Duane, D.B., D.L. Harris, R.O. Bruno, and E.B. Hands. 1975. A primer of basic concept
of lakeshore processes. ACOE Miscellaneous paper #1-75. Ft. Belvoir, VA. 29 pp.
Fulford, E.T. 1985. Reef type breakwaters for shoreline stabilization. Coastal Zone 1985.
ASCE,NY,NY. 1776-1795 pp.
Garbish, E.W., P.B. Woller, and R.J. McCallum. 1975. Saltmarsh establishment and
development. ACOE Ft. Belvoir, VA. Technical Memo #52. 1100 pp.
Grey, D.H. and A.T. Leiser. 1981. Biotechnical slope protection and erosion control. Van
Nostrand Reinhold Co. NY. Chapter 3, 37-65 pp.
Hales, L.Z. 1981. Floating breakwaters: State of-the-art literature review. ACOE.
Technical Report 81-1. Ft. Belvoir, VA. 279pp.
Hill, L., J.D. Lambert and B.B Ross. 1983. Best management practices for shoreline erosion
control. Virginia Cooperative Extension Service Publication 442-004. 6 pp.
Knutson, P.L. 1977. Planting guidelines for marsh development and bank stabilization. ACOE
Technical Aid #77-3. Ft Belvoir, VA. 21 pp.
Lindeburg, M.R. 1989. Civil Engineering Reference Manual. Fifth Edition. Professional
Publications, Inc.
Peck, R.B., W.E. Hanson, and T.H. Thornburn. 1974. Foundation Engineering. Second
Edition. John Wiley and Sons, Inc.
Salvo, K. 1988 Plant Establishment Enhancement Technique, Shoreline Protection on
Steep/Shallow Bank Slopes. U.S.D.A. Soil cons. Serv. Raleigh, North Carolina.
Sharp, C.W., C.R. Belcher and J. Oyler. Undated. Vegetation for tidal stabilization in the
Mid-Atlantic states. USD A, SCS. BroomallPA. 19pp.
Soil Conservation Service 1983. Standards and Specifications for Critical Area Planting,
Code 342. U.S.D.A. Soil Cons. Serv. Technical Guide, Section IV. December. SCS,
Maryland
Tainter, S. 1982 Bluff Slumping and Stability: A Consumer's Guide. National Oceanic
and Atmospheric Administration. Rockville, Maryland. Office of Sea Grant;
Geological Survey. Washington, D.C. Report No. MishU-SG-82-902; NOAA-
82093009, 74pp.,
U.S. Army Corps of Engineers. 1984. Shore Protection Manual, Volumes I and II, Coastal
Engineering Research Center. Waterways Experiment Station, Vicksburg,
Mississippi.
U.S. Army Corps of Engineers joint publication with Water Resources Administration,
Capital Programs Administration, Energy and Coastal Zone Administration, Maryland
Geological Survey, Chesapeake Research Consortium (University of Maryland), and
the US Fish and Wildlife Service (Southern Area Office). 1987. Shore Erosion
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Control A Guide for Waterfront property Owners in the Chesapeake Bay Area.
USACOE Planning Division, Baltimore District. 62 pp.
U.S. Army Corps of Engineers. 1990. Chesapeake Bay Shoreline Erosion Study, Feasibility
Report. USACOE, Baltimore and Norfolk Districts with the State of Maryland and
the Commonwealth of Virginia. USACOE Baltimore, Maryland.
U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA).
Tide Tables. 1992. High and Low Water Predictions. East Coast of North and South
America. National Ocean Service, Rockville, MD.
Wang, H.R. Dean, R. Dalrymple, R Biggs, M. Perlin and V. Klemas, R.K. Spoeri. 1982.
An assessment of shore erosion in Northern Chesapeake Bay and of the performance
of erosion control structures.
Woodhouse, W.W., E.D. Seneca, S.W. Broome. 1976. Propagation and use of S.
alterniflora for shoreline erosion abatement. ACOE Technical Report #76-2 Ft.
Belvoir, VA 72 pp.
Zabawa, C. and C. Ostrom, Eds. 1982. An Assessment of Shore Erosion in Northern
Chesapeake Bay. Tidewater Administration, Maryland Department of Natural
Resources. Annapolis, Maryland. 286 pp.
42
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Table 1 Alternative Bluff Stabilization Approaches Listing Their Positive and Negative Attributes
Option 1-Slope Cut-back, Riprap, and Vegetation Planting
This option involves cutting back the top of the slope and alteration of the slope face angle. The control of wave energy would
be achieved by the establishment of riprap or gabion revetment at the toe of the slope. The non-structural component of this
option would be to seed the graded slope with grasses and shrubs.
Advantages
'Immediate physical control of slumping of slope toe
•Long-term, relatively low maintenance costs
Disadvantages
•High construction costs, logistics of
equipment movement
•Need to remove existing vegetation
•Least natural condition, minimal enhancement
offish and wildlife habitat
Option 2—Sand Bag Breakwater and Marsh Vegetation
This option involves the establishment of an offshore breakwater using standard military class "A" sand bags with a sandy soil
mixture. The top rows of bags would be planted with sprigs of smooth cordgrass (Spartina alterniflora). The intertidal zone
would also be planted with smooth cordgrass. Additional plantings, such as woody vines and shrubs as mentioned above, would
also be planted on the slopes to aid in erosion control.
Advantages
•Not as expensive as most structural controls
•Would reflect a naturalized condition upon
establishment of marsh
•Would provide a benefit to water quality and fish
and wildlife habitat
•The area behind the breakwater would accumulate
sediments, leading to beach or marsh creation
Disadvantages
• Survival of marsh grass sprigs is a concern
•Stability during establishment is
questionable (i.e., due to storm events) and
there will be a possible need to repair
damaged sections
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Table 1. (Continued)
Option 3—Log Breakwater and Vegetation Planting
This option would involve establishment of a log breakwater 50-ft off the eroding bluff. This method typically involves
anchoring floating logs to piles driven in place. Anchoring is accomplished with cables. EA's recommendation would be to
utilize trees that have already fallen to form the breakwater adjacent to the bluff area. In addition, trees at risk of toppling into
the water would be removed and used in the floating breakwater. The slope face would be stabilized with the planting of native
woody vines. The intent of these plantings would be to provide root penetration and leaf cover to hold the soil in place on the
slope. The toe of the slope and the intertidal area would be planted in shrubs and marsh grasses, respectively.
Advantages
•Relatively inexpensive, least expensive of the
options considered suitable
•Rapid protection of toe of slope
•Slope stabilization and wildlife habitat benefit of
vegetation plantings
•Potential benefit to fisheries of trees used in log
breakwater
•The area behind the breakwater will accumulate
sediment, leading to beach or marsh creation
•Reflects a more natural condition than structures
such as rocks or bulkheads
Disadvantages
•Log breakwater may prove ineffective for
controlling wave action without proper
maintenance
•Vegetation establishment may take extended
time, additional plantings may be
necessary, depending upon survival and vigor
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Table I. (Continued)
Option 4—Rock Reef Breakwater and Vegetation Planting
This option would involve establishment of a stone breakwater 50-ft off the eroding bluff. Because of the small distance
between the shore and breakwater, a continuous breakwater (not a series of interrupted breakwaters) is preferred. The
breakwater height should permit overtopping at high-tide to maintain tidal exchange with waters along the shoreline. The slope
face would be stabilized with the planting of native woody vines. The intent of these plantings would be to provide root
penetration and leaf cover to hold the soil in place on the slope. The toe of the slope and the intertidal area would be planted in
shrubs and marsh grasses, respectively. In addition, trees at risk of toppling into the water would need to be removed.
Advantages
•Relatively inexpensive
•Rapid protection of toe of slope
•Slope stabilization and wildlife habitat benefit of
vegetation plantings
•Potential cover benefit to fisheries of large stone
used in breakwater
•The area behind the breakwater will accumulate
sediment, leading to beach or marsh creation
•Stone breakwater requires no maintenance
Disadvantages
•Not as natural in appearance due to large
stone
•Vegetation establishment may take extended
time, additional plantings may be
necessary, depending upon survival and
vigor
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Figure 1. Project area.
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WATER QUALITY IN AREAS OF SUBMERGED AQUATIC VEGETATION (SAV)
REGROWTH IN THE MAGOTHY RIVER, CHESAPEAKE BAY
Peter Bergstrom
U. S. Fish & Wildlife Service
177 Admiral Cochrane Rd.
Annapolis, MD 21401
INTRODUCTION AND GOALS
The underwater plants that make up the Submerged Aquatic Vegetation (SAV)
community in Chesapeake Bay are widely regarded as keystone species of the shallow water
ecosystem. The high ecological value of SAV includes: providing food for waterfowl; providing
shelter for adult and young fish, shellfish, and invertebrates; absorbing nutrients and oxygenating
the water column; and reducing wave energy and promoting settling of suspended sediments.
SAV are also indicators of good water quality; research in Chesapeake Bay has shown
that SAV tend to grow best where water clarity is high and nutrient, chlorophyll, and suspended
sediment levels are low Specific habitat requirements have been established for six water quality
parameters (see Table 1). Declining water quality is one of the main causes of a decline in SAV
acreage in Chesapeake Bay that began in the 1960s.
The Chesapeake Bay Program coordinates and funds an extensive network of water
quality monitoring stations. Data from this network can be used to assess the attainment of SAV
habitat requirements, but they have two limitations: there are few stations in the smaller
tributaries, and the stations are in deeper mid-channel areas, relatively far from the shallow waters
(less than 2 meters) where SAV can grow in Chesapeake Bay.
Volunteer monitoring data can supplement Chesapeake Bay Program data in areas of SAV
regrowth, especially if comparable methods are used. Additional stations can be added at low
cost, and they can be located near SAV beds. It also involves local citizens in assessing the
problems facing their river or other water body.
I started doing volunteer water quality monitoring in two creeks of the Magothy River,
near my residence, in 1991. I discovered that volunteers with the Magothy River Association, a
local environmental group, had been monitoring water quality since 1982, and were interested in
expanding the monitoring to address SAV habitat requirements. Dan Zivi, a life-long resident on
the river and active volunteer monitor, offered the use of his boat and technical assistance.
Monthly water quality monitoring cruises were started in 1992 to identify areas in the
Magothy where water quality is adequate to support Submerged Aquatic Vegetation (SAV)
growth. These areas will be considered for SAV plantings if they do not currently have SAV.
Water quality problems in other areas of the river were also identified.
SITES MONITORED AND METHODS
The Magothy River is located on the western shore of the Chesapeake Bay, just south of
the Patapsco River and Baltimore, and just north of the Bay Bridge, the Severn River, and
Annapolis. It is a small tributary, about 7 miles long, and most of its tidal portion is classified as
the mesohaline salinity regime (5 to 18 parts per thousand salinity). The locations of the sites
monitored, all in the tidal portion, are shown in Figure 1. The shaded area in Figure 1 shows
general areas of SAV regrowth in the last few years. We analyzed the usual volunteer water
quality parameters in the field (water temperature, salinity, pH, Secchi depth, and dissolved
oxygen, from surface and bottom samples except for Secchi depth), and we filtered surface water
47
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samples for later laboratory analysis for nutrients, chlorophyll a, and total suspended solids at
Chesapeake Biological Laboratory in Solomons, Maryland.
RESULTS
Aerial surveys of SAV in Chesapeake Bay, conducted by Virginia Institute of Marine
Science (VIMS) since 1978, showed that the Magothy River had a sharp decline in SAV between
1979 and 1984, followed by a modest resurgence in 1993 and 1994 (Figure 2).
Average water quality varied along the length of the river in a linear gradient for most
parameters. For example, surface water temperature, salinity, and pH showed a fairly linear
gradient as warmer, lower pH, and fresher water from the river mixed with cooler, higher pH, and
saltier water from the Bay.
However, average water quality varied in a non-linear fashion along the length of the river
for two parameters, nitrogen and Secchi depth. The middle reaches of the river had the best
water quality for these two SAV habitat requirements; this area also had expanding SAV beds
during 1992-1994. This spatial pattern was most evident for dissolved inorganic nitrogen (DIN),
calculated from the sum of the ammonia, nitrite, and nitrate concentrations. Too much DIN
inhibits SAV growth, by stimulating algae growth and reducing water clarity. The DIN medians
in the Magothy for 1993 and 1994 were below the habitat requirement for SAV (better water
quality) in the middle reaches, but were above it at both upriver and downriver sites (Figure 3).
The high spring levels of DIN were primarily nitrate. The sites closest to SAV beds achieved the
DIN medians in one or both years (sites 7, 8, 10, and 11 in Figure 3). Average Secchi depths also
tended to show better water quality (higher Secchi depths) in the middle reaches, and these four
sites also achieved the SAV habitat requirement for Secchi depth in 1993 (Figure 4). Average
phosphorus levels (orthophosphate) were low enough to permit SAV growth at almost all sites.
Weather conditions also affected water quality. Although both 1993 and 1994 had higher
than normal spring rainfall, the high rainfall continued longer in 1994, and may have contributed
to reduced Secchi depths and water clarity in 1994 (Figure 4). Chlorophyll a medians were also
higher in 1994 than in 1993. The increase in SAV area continued in 1994 in spite of the lower
water clarity, however (Figure 2).
We plan to use these results to identify areas for SAV restoration. Several areas of the
Magothy upriver from the area of SAV regrowth have water quality that should support SAV
growth, and may be suitable sites for planting SAV. These include the mouths of Cypress Creek,
Mill/Dividing Creek, and Blackhole Creek. We plan to observe other SAV planting efforts in
Anne Arundel County rivers and identify the most successful planting techniques to use.
CONCLUSIONS
• The middle reaches of the Magothy, not the mouth, tended to have the best water quality;
these areas also had expanding SAV beds during 1992-1994. This supports the use of the
SAV habitat requirements to predict areas where SAV should be able to grow.
• High dissolved inorganic nitrogen levels and low Secchi depths (water clarity) may be
limiting SAV growth in the Magothy.
• Inter-annual variability in rainfall and flow affected water quality in the Magothy River.
Studies of water quality in relation to SAV growth should be conducted over 3 or more
years to account for these differences.
• Several areas of the Magothy upriver from the area of SAV regrowth have water quality
that should support SAV growth, and may be suitable sites for planting SAV
48
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ACKNOWLEDGMENTS
Over 20 people assisted us in the field over three years, and we could not have done the
monitoring without their help. Christian Kurrle was particularly helpful; he helped design the
monitoring network with George Gibson in 1990, and took us in his boat for most of our 1992
cruises. The Chesapeake Bay Trust provided financial support in 1992, 1993, and 1994, and
monitoring equipment was provided by Anne Arundel County Planning and Code Enforcement
and the Alliance for the Chesapeake Bay.
49
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Magothy River
Chesapeake
Bay
Ritchie
Highway'
(MD2)
MR13
*
\
\
\
\
\
\
\
Figure 1. Map of Magothy River sampling sites. Shaded area is the approximate area where
Submerged Aquatic Vegetation (SAV) beds have been expanding in the
last few years.
50
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250
200 •
g 150
>• 100
o
en
ra
50
-Tier I goal (239 ha)
78 79
84
85 86
87 89
Year
90 91
92
93 94
Figure 2. Submerged Aquatic Vegetation (SAV) area mapped in the Magothy
River by year. SAV was mapped by aerial photography once a year, and none
was recorded between 1989 and 1992 (1987 had 0.3 hectare). The Tier I goal
(239 hectares) is an interim restoration goal for the Magothy.
Figure 3. Median surface Dissolved Inorganic Nitrogen (milligrams per liter as N,
April- or May-October) by site and year. The SAV Habitat Requirement (HR) in '
mesohaline regions, 0.15 mg/l, is shown.
Figures 2 and 3
51
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O --1993
* 1994
M9 M10 01 23456 6A 78
I Creeks I Magothy River Site
10 11 12 13
Figure 4. Median Secchi depth (meters, April- or May-October) by site and year.
The SAV Habitat Requirement (HR) in mesohaline regions, 1.0 meters, is shown.
-------
THE EFFECT OF BULKHEADS ON FISH DISTRIBUTION AND ABUNDANCE:
A COMPARISON OF LITTORAL FISH AND INVERTEBRATE ASSEMBLAGES AT
BULKHEADED AND NON-BULKHEADED SHORELINES \ A BARNEGAT BAY
LAGOON
Donald M Byrne
New Jersey Division of Fish, Game & Wildlife
Nacote Creek Research Station
Port Republic, NJ 08241
INTRODUCTION
Bulkhead construction is a common and effective method of shoreline protection and
stabilization. However, bulkheads driven into shallow subtidal waters convert gradual-sloped
bottom habitat with an intertidal zone into vertical "bottom" with no intertidal zone. Such
bulkheads virtually erase the land-water ecotone with potentially dire consequences for the
aquatic fauna.
In the early 1980s, the New Jersey Division of Coastal Resources, the agency responsible
for coastal zone management, was receiving large numbers of permit applications for bulkhead
construction. Most of these project sites were in man-made lagoon developments, of which there
are 78 in the Atlantic shore region of New Jersey comprising 267.3 km of lagoons, or canals
(Nieswand et al., 1972). Lagoon systems were created by dredging salt marshes and some
forested wetlands largely between 1950 and 1970 to provide waterfront real estate, with dredge
spoils often used as fill for housing sites.
Lagoon canals have similar features. They are generally about 30m wide, usually less
then 1 km long, and depth is usually 3 m or more, often exceeding 6 m where fill has been mined.
Water quality tends to be poor due to restricted circulation. Strong vertical stratification during
warm seasons frequently results in bottom anoxia.
In view of these negative attributes, the importance of protecting the subtidal shallows
along lagoon banks from bulkhead impacts was questioned. A study was undertaken to validate
the assumption that these shallows function as well as natural habitats by using fish and
macroinvertebrate species composition and abundance as a basis for evaluation. In addition, a
comparison of bulkheaded and non-bulkheaded shorelines was made on the same basis. This
report presents some of the results of that work.
METHODS
Laurel Harbor, a lagoon development on western Barnegat Bay, Lacey Township, NJ was
selected for study because it had numerous bulkheaded and non-bulkheaded shallow habitats
distributed throughout its northern lagoon system. Two sets of paired bulkheaded/non-
bulkheaded stations were established, one on the main canal and the other on a side canal. Paired
stations were located on opposite banks directly across from each other.
Stations were sampled every two weeks during daylight from 29 March 1983 through 28
March 1984 (except when prevented by ice during winter), with a bag seine of 1.2 x 8.2 m of 6.35
mm square mesh (4 x 27 ft., 0.25 inch square mesh). Samples were collected twice each day,
once in the morning and once in the afternoon, by hand-walking the seine parallel to shore a
predetermined distance. Shoreline references identified start and stop points and the same area
was seined each date. Because shallow water habitats along the lagoon were like narrow ledges,
generally less than 3 m wide, the outer wing of the seine was hauled ahead of the inner wing to
53
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minimize fish escapement. At the end of a haul the net was simply dragged ashore at non-
bulkheaded sites, but at bulkheads it was carefully pursed, then lifted vertically to the top of the
bank. Distance and width seined were measured with a tape and the catch standardized to a
smapled area of 50 m2 Fish and macroinvertebrates were enumerated and weighed by species
immediately after capture and released at the site of their collection.
RESULTS AND DISCUSSION
The littoral fish fauna of Barnegat Bay and vicinity has been studied extensively
(Marcellus, 1972; McClain, 1973 & 1979; Tatham et al., 1984). These studies showed the fauna
dominated by five species which collectively accounted for 87-96% of the total number offish
collected. Atlantic silverside, bay anchovy, threespine stickleback, inland silverside, and
mummichog. The species composition of lagoon habitats was .similar, however relative
abundance of the dominant species differed. In the lagoon, inland silverside and mummichog
were most abundant, followed by sheepshead minnow, bay anchovy, and rainwater killifish.
These five collectively represented 91% of all the fish collected.
The diminished importance of Atlantic silverside and threespine stickleback in the lagoon
compared to the bay is probably related to the scarcity in the lagoon of habitats these species seem
to prefer - sandy bottoms in high energy environments for the silverside, and submerged aquatic
vegetation for the stickleback. The quiescent backwaters of the lagoon appeared to harbor a fish
community resembling that found in salt marsh ponds and potholes (with the exception of bay
anchovy).
In any case, the lagoon shallows did indeed appear to function as well as natural habitat in
terms of the diversity and number of fishes and macroinvertebrates captured there. A total of 30
fish and six macroinvertebrates was collected during the year, with the annual mean number of
fish ranging from 114-287 fish per 50 m2 among the four sampling sites, and 70-255 shrimp per 50
m2for grass shrimp, the most abundant invertebrate (consisting of both Palaemonetes pugio and
P. vulgaris combined).
The question of whether bulkheaded and non-bulkheaded shallows in the lagoon were of
equal habitat value, as measured by species composition and abundance, must be answered no.
True, at all sampling sites the species composition was virtually identical. Likewise, temporal
variation at all sites was typical for that of a Mid-Atlantic estuary, with cold season scarcity and
warm season plenty, peaking in late summer and fall as growing young became susceptible to
capture by the seine net. However, as seen in the graphs, comparisons between paired
bulkheaded and non-bulkheaded shorelines showed catches at bulkheads were consistently lower.
Statistical comparison of total fish and invertebrate catches using Wilcoxon's signed rank
test (P>0.05, two-tailed) on data paired by sampling date and replicate indicated significant
differences for all comparisons: catches were greater at non-bulkheaded shallows. This
relationship was evident for most species as well, with the comparisons for sheepshead minnow
and mummichog the most striking.
The reason for diminished numbers of littoral fishes and shrimp at bulkheaded shorelines
was probably related to the low level of structural complexity in the habitat. Submerged aquatic
vegetation, attached macrophytic algae, snags, overhanging and submerged branches of upland
vegetation, and wood debris were scarce or absent in the bulkheaded shallows, but characteristic,
to some degree, of the non-bulkheaded shorelines. Such features provide foraging, hiding, and
spawning areas for the fishes and invertebrates comprising the littoral fauna.
New Jersey policies governing waterfront development require new bulkhead construction
at or above the mean high water line when feasible, which conserves the shallow intertidal and
54
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subtidal habitats required by the littoral aquatic community. When bulkheads are placed
subtidally, their negative physical impacts (as distinguished from chemical impacts caused by
leaching of wood preservatives or antifouling treatments into water and bottom sediments) may
be mitigated to some extent by adding structural complexity to the site, such as brush piles,
plantings, etc In the absence of such mitigation, or perhaps even with it, subtidal bulkheads
inflict an environmental cost. The cost is borne by the littoral community, which is diminished.
LITERATURE CITED
Marcellus, K.L. 1972. Fishes of Barnegat Bay, New Jersey, with particular reference to
seasonal influences and the possible effects of thermal discharges. Ph.D. Thesis,
Rutgers University, New Brunswick, NJ. 190 pp.
McClain, J.F. 1973. Phase I - fish studies. Pages 1-74 in Studies of the upper Barnegat
system. New Jersey Division of Fish, Game and Shellfish Report No. 10M.
McClain, J.F. 1979. Phase I - fish studies. Pages 7.1-7.14 with 2 appendices in
Comparison of natural and altered estuarine systems: The field data - Volume II.
Rutgers University Center for Coastal and Environmental Studies and New Jersey
Department of Environmental Protection.
Niewsand, G.H., C.W. Stillman, and A.J. Esser. 1972. Inventory of estuarine site
development lagoons systems: New Jersey shore. New Jersey Water Resources
Research Institute, Rutgers University, New Brunswick, NJ. 36 pp.
Tatham, T.R., D.L. Thomas, and D.J. Danila. 1984. Fishes of Barnegat Bay. Pages
241-280 in M.J. Kennish and R.A. Lutz, eds. Ecology of Barnegat Bay, New Jersey.
Springer-Verlag, New York, NY.
55
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1600-1
O-O BO bulkhead
I bulkhead
Pair 1
300i
250-
CM
O 200-
C. 190-
0
|
C
100-
50-
0
0-3 30 bulkhead
m-m bulkhead
Pair 1
CM
E
•L.
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PHYTOPLANKTON CHLOROPHYLL A VS. BENTHIC MICROALGAL
CHLOROPHYLL A IN ESTUARINE AND COASTAL WATERS: IMPLICATIONS FOR
REMOTE SENSING
Lawrence B. Gaboon
Dept. of Biological Sciences
UNC Wilmington
Wilmington, N.C. 28403
Guy R. Beretich, Jr.
College of Veterinary Medicine
N.C. State Univ.
Raleigh, N.C. 27606
Janice E. Nearhoof
Dept. of Biological Sciences
UNC Wilmington
Wilmington, N.C. 28403
INTRODUCTION
There is great interest in the development of remote sensing techniques for. determining
the biomass and production of plants, particularly phytoplankton, in aquatic ecosystems, e.g.,
Berthon and Morel (1992), Morel and Berthon (1989), Platt and Sathyendrenath (1988). Until
very recently most remote sensing techniques employed quantification of spectral properties of
water masses under excitation by sunlight, e.g., Brown et al. (1985), Ishizaka (1990).
Phytoplankton can be detected in this way by either the chlorophyll fluorescence signal at
approximately 685 nm (Gitelson, 1992) or by the blue:green reflectance ratio (443:550 nm)
(Smith, 1981). The sensible portion of the water column is usually considered to be one
attenuation depth (= 1/k, where k is the attenuation coefficent for light at respective wavelengths).
Algorithms have been developed that predict total plant pigment in the euphotic zone from
pigment sensed in the surface layer of the water column, e.g., Morel and Berthon (1989).
Fluorescence measurements can only sense the top few centimeters of water, owing to the high
attenuation of long-wavelength light, whereas blue:green reflectance techniques sense the pigment
within a significantly deeper and more representative portion of the water column.
Studies of shallow coastal and estuarine ecosystems have demonstrated that benthic
microalgal biomass can substantially exceed that of phytoplankton in the overlying water column
and microalgal production can approach that of the phytoplankton, e.g., Cahoon and Cooke
(1992), Cahoon et al. (1993), Beretich (1992), Nearhoof (1994). Benthic microalgae can be
grazed directly by deposit feeders (Lopez, 1980) or, after suspension by physical processes, by
suspension feeders (Baillie & Welsh, 1981). Consequently, benthic microalgae are important in
shallow water food chains.
We examine the utility of remote sensing techniques to quantify benthic microalgal
biomass in shallow coastal and estuarine ecosystems. Jobson et al. (1980) used a tower-mounted
multispectral scanner to quantify benthic microalgal biomass in intertidal habitats, but this paper
focuses on sensing microalgae in subtidal habitats. Fluorescence-based sensing techniques would
only be useful for sensing microalgae in exposed intertidal habitats and, perhaps, in extremely
57
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shallow waters (< 2-3 cm depth). Consequently, we consider the utility of reflectance-based
remote sensing techniques. We address several questions:
1. How frequently do benthic microalgae occur within one attenuation depth for
blue:green reflectance sensor systems?
2. Is there a useful predictive relationship between sensible or depth-integrated
phytoplankton biomass and benthic microalgal biomass when benthic microalgal
populations occur below one attenuation depth?
3. Is there a predictive relationship between the white light extinction properties of the
water column and benthic microalgal biomass?
METHODS AND MATERIALS
We sampled phytoplankton and benthic microalgae at four locations in the continental
shelf waters of the eastern United States (Stellwagen Bank, Massachusetts; Onslow Bay, North
Carolina; Key Largo, Florida; Cedar Key, Florida) and at 87 sites within six estuarine ecosystems
in North Carolina (Cape Fear River Estuary, Masonboro Sound Estuarine Research Reserve,
Howe Creek, New River, Bogue Sound, and Neuse River Estuary), which were sampled at
different times of year and chosen to represent a range of depths, bottom types, and water
clarities.
Phytoplankton were collected at the surface with plastic vessels and at lower depths at the
continental shelf sites with Niskin samplers. Water samples were filtered in the field through glass
fiber filters, which were frozen, and, in the laboratory, extracted in 90% acetone for analysis of
chlorophyll a and phaeopigments by fluorometry (Parsons et al., 1984).
Benthic microalgae were sampled by SCUBA divers using hand-held 2.5 cm corers at
continental shelf sites. At estuarine sites, a small Peterson grab was used to collect surface
sediments, which were then cored by 2.5 cm corers. Sediment cores were frozen, then extracted
with 100% acetone and analyzed for chlorophyll a according to Whitney and Darley (1979). A
subsample of each extract was also used to estimate chlorophyll a and phaeopigments
fluorometrically, as above. Details of these procedures can be found in Cahoon and Cooke (1992)
and Beretich( 1992).
The white-light attenuation coefficient, k, was estimated for each site using either
measurements of quantum flux through the water column at several depths measured by a Li-Cor
LI-193SA 4-pi underwater quantum sensor interfaced with a Li-Cor LI-1000 datalogger or by
measurement of secchi depth using a 30 cm white disk. Attenuation depth for blue:green
reflectance was calculated as k x 1.2, following Smith (1981) and assuming average chlorophyll a
concentrations in the range 0.1 to 1.0 mg m"3
RESULTS
We detected benthic microalgal biomass as chlorophyll a at every estuarine site, despite
extremely low light fluxes to the bottom at some sites, a result of high light attenuation
coefficients and/or relatively great depth. A plot of benthic microalgal microalgal biomass vs.
attenuation depth number (calculated as the product of measured white-light attenuation
coefficient, k, x depth) shows that a substantial proportion of benthic microalgal populations in
North Carolina estuaries live below one attenuation depth ( k x depth = 1 for white light, k x
depth = 1.2 for blue:green reflectance) (Figure 1). A sensor or algorithm able to quantify
microalgal pigments accurately to depths equal to 2 attenuation depths would still miss
approximately 25% of the microalgal populations we sampled.
58
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Remote sensing techniques using blue:green reflectance as a measure of phytoplankton
biomass detect total plant pigment (chlorophyll a + phaeopigments), then convert to chlorophyll a
using either a statistical relationship between the two quantities as in Morel and Berthon (1989) or
empirically determined ratios from field sampling. We measured total pigment directly for
phytoplankton and benthic microalgae sampled at our continental shelf sites and found no
statistically significant relationship for either benthic pigment vs. surface pigment (pigment in the
sensible surface layer = one white-light attenuation depth) (Figure 2) or benthic pigment vs.
integrated water column pigment (Figure 3).
Comparisons of benthic microalgal chlorophyll a vs. integrated phytoplankton chlorophyll
a for the estuarine sites we sampled suggest an inverse relationship between these two kinds of
biomass, but the relationship is not very consistent (Figure 4). High phytoplankton biomass is
associated with low benthic microalgal biomass, but low phytoplankton biomass is unpredictably
related to benthic microalgal biomass.
DISCUSSION
Our data show that benthic microalgal populations are distributed to depths substantially
below those where remote sensors can detect them directly. Cahoon et al. (1993) established that
benthic microalgae receiving light fluxes as low as 0.1 % of surface incident radiation could
sustain significant positive production. Other distribution data (Cahoon et al., 1992; Cahoon,
unpubl. data) confirm this capability to exist under very low light conditions. Thus, a large
fraction of all benthic microalgae populations are essentially invisible to remote sensors using
sunlight as an excitation source
Benthic microalgal biomass is not clearly related to phytoplankton biomass in the
overlying water column in any predictable manner. One would expect that shading by dense
phytoplankton populations would reduce benthic microalgal populations, and that low
phytoplankton populations would permit higher light fluxes to the bottom and more extensive
benthic microalgal growth. Our data show some evidence for such an effect (Figures 1,4), but the
relationship is poor. Furthermore, the contribution of phytoplankton pigments to light attenuation
is significant only at high phytoplankton densities; at low densities, non-phytoplankton sources of
scattering and absorption become much more important (Edmondson, 1980). Thus, no broadly
useful relationship between remotely sensible phytoplankton pigment and benthic microalgal
biomass appears to exist.
There are additional constraints on the comparability of phytoplankton and benthic
microalgae that limit the potential utility of indirect estimations of benthic microalgal biomass
through measurement of phytoplankton biomass. First, physical processes suspend variable
fractions of benthic microalgae, thus blurring the distinction between phytoplankton and benthic
microalgae. These "tychopelagic" forms (after Bold & Wynne, 1985) will constitute a variable
fraction of sensible phytoplankton, depending on the frequency, intensity, and duration of
suspension processes Second, benthic microalgae and phytoplankton, although sharing a high
proportion of diatoms, are dominated by very different diatom species assemblages, (Cahoon &
Laws, 1993). The fluorescence and/or reflectance characteristics of benthic forms may differ from
those of planktonic forms, and require further study before application of remote sensing
algorithms originally developed for phytoplankton. Third, variable fractions of benthic microalgal
populations occur below the sediment surface, and, although not productive, may remain viable
and return to the surface via migration or perturbation. Finally, the factors controlling biomass of
benthic microalgae are quite different from the factors controlling phytoplankton populations.
Benthic microalgae are supported by a different set of nutrient sources, experience a different set
59
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of light fields, are grazed by a different set of grazers, and apparently show different growth
strategies than phytoplankton (Gould & Gallagher, 1990; Cahoon, unpubl. data). These ecological
differences are likely to drive important differences in the characteristics of benthic microalgae, so
that remote sensing techniques used to quantify them must take into consideration their distinct
biology.
The recent development of directed energy excitation techniques coupled with multi-'
spectral response measurements holds promise for the quantification of benthic microalgae, at
least in some habitats, e.g., Lillycrop and Estep (1995). For example, use of airborne lasers can
direct substantially more energy through the water column, increasing the depth from which
sensible reflectances can be obtained. Multi-spectral scanners with good frequency resolution may
permit detection of characteristic marker pigments and allow distinction of benthic microalgal
reflectance spectra from those of phytoplankton.
60
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LITERATURE CITED
Baillie, P.W., and B.L. Welsh. 1980. The effect of tidal resuspension on the distribution of
intertidal epipelic algae in an estuary. Estuarine and Coastal Marine Science 10:165-
1 • '.
Beretich, G.R., Jr. 1992. Comparisons of water column and benthic chlorophylls on the
eastern U.S. continental shelf. Unpublished M.S. thesis, UNC Wilmington.
Berthon, J.-F., and A. Morel. 1992. Validation of a spectral light-photosynthesis model and
use of the model in conjunction with remotely sensed pigment observations.
Limnology and Oceanography 37:781-796.
Bold, H.C., and M.J. Wynne 1985. Introduction to the Algae: Structure and Reproduction,
2nd ed. Prentice-Hall, Englewood Cliffs, N.J.
Brown, O.B., R.H. Evans, J.W. Brown, H.R. Gordon, R.C. Smith, and K.S. Baker. 1985.
Phytoplankton blooming off the U.S East Coast: a satellite description.
Science229:163-167.
Cahoon, L.B. and J.E. Cooke. 1992. Benthic microalgal production in Onslow Bay, North
Carolina, USA. Marine Ecology Progress Series 84:185-196.
Cahoon, L.B., and R.A. Laws. 1993. Benthic diatoms from the North Carolina continental
shelf: Inner and mid shelf. Journal of Phycblogy 29:257-263.
Cahoon, L.B., R.A. Laws, and T.W. Savidge 1992. Characteristics of benthic microalgae
from the North Carolina outer continental shelf and slope: Preliminary observations,
pp. 61-68 in Cahoon, L B., ed. Diving for science. 1992, American Academy of
Underwater Sciences, Costa Mesa, CA.
Cahoon, L.B., G.R Beretich, Jr., C.J. Thomas, and A.M. McDonald. 1993. Benthic
microalgal production at Stellwagen Bank, Massachusetts Bay, USA. Marine Ecology
Progress Series 102:179-185.
Edmondson, W.T. 1980. Secchi disks and chlorophyll. Limnology and Oceanography
25:378-379.
Gitelson, A. 1992. The peak near 700 nm on radiance spectra of algae and water:
Relationships of its magnitude and position with chlorophyll concentration.
International Journal of Remote Sensing 13:3367-3373.
Gould, D.M., and E.D. Gallgher 1990. Field measurement of specific growth rate, biomass,
and primary production of benthic diatoms of Savin Hill Cove, Boston. Limnology
and Oceanography 35:1757-1770.
Ishizaka, J 1990 Coupling of coastal zone color scanner data to a physical-biological model
of the southeastern U.S. continental shelf ecosystem. 3. Nutrient and phytoplankton
fluxes and CZCS data assimilation. Journal of Geophysical Research 95:20,201-
20,212.
Jobson, D.J., R G Zingmark, and S.J. Katzberg. 1980. Remote sensing of benthic
microalgal biomass with a tower-mounted multi-spectral scanner. Remote Sensing of
Environment 9:351-362.
Lillycrop, W.J., and L.L Estep. 1995. Generational advancements in coastal surveying,
mapping Sea Technology 36:10-16.
Lopez, G.R. 1980. The availability of microorganisms attached to sediment as food for some
marine deposit-feeding molluscs, with notes on microbial detachment due to the
crystalline style, pp. 387-406, in Tenore, K.R., and B.C. Coull, eds., Marine Benthic
Dynamics, University of South Carolina Press, Columbia, SC.
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Morel, A., and J.-F. Berthon. 1989. Surface pigments, algal biomass profiles, and potential
production of the euphotic layer: Relationships reinvestigated in view of remote-
sensing applications. Limnology and Oceanography 34:1545-1562.
Nearhoof, I.E. 1994. The distribution and relative abundance of benthic microalgae and
phytoplankton in North Carolina estuaries of varying depth and water clarity.
Unpublished M.S. thesis, UNC Wilmington.
Parsons, T.R., Y. Maita, and C.M. Lalli. 1984. A Manual of Chemical and Biological
Methods for Seawater Analysis. Pergamon Press, New York.
Platt, T., and S. Sathyendrenath. 1988. Oceanic primary production: estimation by remote
sensing at local and regional scales. Science 241:1613-1620.
Smith, R.C. 1981. Remote sensing and the depth-distribution of ocean chlorophyll. Marine
Ecology Progress Series 5:359-361.
Whitney, D.E., and W.M. Darley. 1979. A method for the determination of chlorophyll a in
samples containing degradation products. Limnology and Oceanography 24:183-186.
62
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Figure 1. The distribution of benthic microalgal biomass (mg m2) in North Carolina estuaries vs. attenuation depth numbers,
estimated as the product of white-light attenuation coefficient, k (m'), and depth (m).
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Figure 3. Relationship between benthic microalgal pigment (chlorophyll a + phaeopigments)
and integrated phytoplankton pigments at continental half sites on U.S. east coast.
65
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Figure 4. Relationship between benthic microalgal biomasss and integrated phytoplankton biomass (mg chlorophyll a m2) at
estuarine sites in North Carolina.
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DELAWARE'S HIGH-LEVEL TIDAL MARSH IMPOUNDMENTS AS FISH HABITAT:
IMPROVING FISH ACCESS AND SURVIVAL WHILE MAINTAINING
TRADITIONAL IMPOUNDMENT MANAGEMENT GOALS
John H Clark
Delaware Division of Fish and Wildlife
DNREC, P.O. Box 1401
Dover, DEI 9903
INTRODUCTION
High-level tidal marsh impoundments (defined here as areas of marsh surrounded by dikes
to remove the surrounded marsh from natural tidal waterflow) account for nearly 10,000 acres of
Delaware's 90,000 acres of tidal marsh. Impoundments have a long history of use in Delaware,
during which they have been subjected to widely varying management methods. Delaware's
oldest impoundments, some dating back to the 17th century, were managed either to provide
flood control or produce salt-hay for livestock. However, the bulk of Delaware's impoundment
acreage was created during this century with the management goals of either enhancing the
marsh's habitat value to waterfowl, providing mosquito control, or a combination of these two
goals.
The Delaware Division of Fish and Wildlife manages several large high-level tidal marsh
impoundments. These impoundments were managed primarily for waterfowl habitat enhancement
using management practices common to most large impoundments. However, the management
practices used for waterfowl habitat enhancement were often detrimental to other organisms, such
as fish. Fish use of the Division's Little Creek and Port Mahon impoundments was studied during
1990 through 1994 to determine what impacts impoundment management had on fish movement
and survival The results of this study were used to propose and implement modifications to the
management practices that would improve fish access to the impoundments while maintaining
traditional impoundment management goals of waterfowl habitat enhancement.
IMPOUNDMENT MANAGEMENT HISTORY
Initial high-level impoundment management practices were devised to improve the
waterfowl habitat value of the impounded marsh by converting brackish/saline water marsh to
fresh water marsh and then manipulating the impounded marsh water levels to maximize the
impounded marsh's attractiveness to waterfowl. These management practices, used effectively on
several of Delaware's federally managed impoundments, were impossible to fully implement on
the Division's impoundments because of inadequate freshwater inputs, therefore brackish tidal
water had to be used to fill these impoundments. The impoundments were pumped full with
brackish water in the fall to provide the combination of open water and vegetation most attractive
to migratory waterfowl. The impoundments remained full during winter through early spring and
impoundment salinities usually dropped during this period because of high precipitation and low
evaporation. The water levels of these impoundments were then allowed to drop via evaporation
during the spring and summer so vegetation could regrow for the next waterfowl migration, but
water levels still remained high enough during the summer to provide mosquito control. These
practices provided little impoundment access to estuarine organisms and were not particularly
beneficial to wildlife other than waterfowl. However, considering the management goals of the
time, the most serious drawback of these practices was they were ultimately detrimental to
impoundment vegetation and thus to waterfowl. Impoundment vegetation, after several years of
67
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excellent production, died off in these impoundments because years of brackish water evaporation
raised the salinity of the impoundment soils until the soil was too saline to support plant life.
Impoundment use by waterfowl, particularly nesting by indigenous ducks (Whitman, 1987),
declined drastically after the vegetation died off.
Efforts made during the mid-1980s to restore the impoundments to their original
productivity led to improved impoundment management practices (Whitman, 1991). Managers
abandoned unrealistic plans to convert the impoundments to fresh water marshes and instead
attempted to restore them as highly productive brackish water marshes. Impoundment pumps
were replaced by water control structures (Figure 1) modeled after those used in South Carolina
(Williams, 1987) which allowed greater, yet less costly, impoundment water level control than the
pumps. Management goals still focused on creating attractive waterfowl habitat, but the updated
management practices stressed intensive water level management. Impoundments were still
flooded in the fall and maintained at high water levels through the winter to attract waterfowl and
allow hunter access. However, instead of then allowing evaporation to dictate water levels as in
the original practices, water levels were dropped via the water control structures in early spring to
expose the impoundment surface so that desired vegetation could germinate. During the spring
and summer months, the impoundments were flooded and drained repeatedly to keep soil
salinities below 20 parts per thousand (ppt) and thus, maintain optimal conditions for growing the
desired brackish vegetation. These practices resulted in substantial impoundment revegetation
and thus, improved waterfowl habitat. Recent management goals, such as increased estuarine
organism access to the impoundments, were also advanced by these practices.
CURRENT AND PROPOSED IMPOUNDMENT MANAGEMENT PLANS
The proposed impoundment management plan, based on a five-year study offish access
and survival in the impoundments (Clark, 1995), is a modification of the current plan and is
intended to preserve the original impoundment management goal of waterfowl habitat
improvement while also advancing the more recent impoundment goals of enhancing estuarine
organism impoundment access. The proposed plan uses the current management practices
(Whitman, 1991) to control water levels, but emphasizes additional water exchange compared to
the current plan.
The major differences between the two plans concern summer water exchange and the
timing of impoundment filling to maximum water depth in the fall. The proposed plan calls for
more-frequent summer water exchange than the current plan and it requires regular monitoring of
summer impoundment water quality, particularly dissolved oxygen. The proposed plan also
requires water exchange to continue later into the fall than the current plan to prevent transient
estuarine organisms typically present during the fall, such as Atlantic croaker, from being trapped
in the impoundments and exposed to potentially lethal winter water temperatures. The proposed
plan, unlike the current plan, does not attempt to limit salinity to 20 ppt because to do so would
require reducing water exchange to the detriment of estuarine organisms. Although limiting
salinity to a 20 ppt maximum is certainly desirable for optimizing production of brackish water
vegetation, abandoning efforts to maintain salinity below 20 ppt is actually not much of a
difference from the current plan since in practice it is usually impossible to maintain salinities
below 20 ppt in these impoundments throughout the summer due to their lack of freshwater
inputs.
Both the current plan and the proposed plan have a major drawback compared to the
original plan in that neither provide as much mosquito control. The original plan called for the
impoundments to remain inundated throughout the summer to prevent salt marsh mosquito
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breeding. However, both the current and proposed plans require frequent summer water
exchange which, although vital for impoundment vegetation, creates good salt marsh mosquito
breeding conditions. The frequent water exchange does allow larvivorous fish, such as
mummichogs, access to the mosquito broods, but this alone does not always provide the level of
mosquito control the public demands
The two plans are further contrasted by comparing their annual impoundment water
management cycles (Table 1). The following plan summaries begin with the fall flooding of the
impoundments. Differences between the plans are explained in the proposed plan summary.
Details of the current management plan were described by Whitman (1989).
CURRENT IMPOUNDMENT MANAGEMENT PLAN
Under the current plan, the impoundments are filled to their maximum level (no more than
2 feet above the impoundment surface) in early fall, typically early October, and remain at this
level through early winter to meet waterfowl habitat and hunter access goals. Waterfowl are
attracted by the combination of open water and vegetation, and the depth allows hunters access
by boat to the entire impoundment. The impoundments are drawn down and reflooded from late
January to March as necessary to prevent ice from forming on the surface and thus, preventing
waterfowl from foraging.
The second phase of the current management plan, beginning in early March, has the goal
of providing nesting habitat for local waterfowl. The impoundments remain at maximum water
level through early March to ensure nesting waterfowl do not choose nesting sites that could be
flooded when impoundments are filled Water levels are gradually drawn down from maximum
level to 50% pool (50% of the impoundment surface covered with water) during mid-March
through mid-April. Water exchange is accomplished during this drawdown by allowing some
tidal inflow during high tides.
The third phase of the current management plan, beginning in mid-April and continuing
through August, has the following goals: (1) allowing maximum revegetation; (2) maintaining
permanent water for submergent plants and invertebrates; (3) providing food and cover for
waterfowl broods; (4) providing partial estuarine exchange for estuarine organism access; and (5)
providing shorebird and wading bird habitat. Although impoundment water levels remain at 50%
pool during this phase, water exchange is frequent to maintain the lowest possible salinity levels.
However, water exchange rates are deemed adequate as long as impoundment salinity does not
exceed estuarine salinity and exchange is halted after heavy rains in efforts to keep the salinity as
low as possible. Exposed areas-of the impoundments are flooded and drained monthly as
necessary to prevent excessive soil salinities from occurring.
The final phase of the current plan, beginning in September and ending in early October,
has the goals of removing excess nutrients, enhancing soil oxidation and stabilization, and
distributing seeds for the following year's growth. The impoundments are flooded to maximum
levels and drained to minimum levels once or twice during this phase. The impoundments are
then refilled to their maximum level in early October to start the next annual management cycle.
PROPOSED IMPOUNDMENT MANAGEMENT PLAN
The impoundments are also filled to their maximum level (no more than 2 feet above the
impoundment surface) in early fall in the proposed plan, typically early October, to meet
waterfowl habitat and hunter access goals. However, unlike the current plan, water exchange
continues through the fall to allow continued impoundment access and egress to estuarine
organisms, particularly fall transients. Impoundment drawdowns are coordinated with the fall
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waterfowl hunting seasons. For example, if a three-week gap is scheduled between seasons, the
impoundments are drawn down during the first ten days and reflooded during the last ten days,
depending on the tides. Impoundment inflows and outflows should be sampled during this phase
to determine estuarine organisms present in the impoundments and associated estuaries. If this
sampling shows substantial numbers of fall transient species are present in the impoundments and
associated estuaries, then water exchange should continue in the periods between hunting seasons
to allow fall transients access to the impoundment habitat, yet prevent these same fall transients
from being trapped in the impoundments during prolonged cold spells. As in the current plan, the
impoundments are drawn down and reflooded from late January to March.
The second phase of the proposed management plan is similar to the current plan. The
impoundments remain at maximum water level through early March to ensure nesting waterfowl
do not choose nesting sites that could be flooded when impoundments are filled. Water levels are
gradually drawn down from maximum level to 50% pool during mid-March through mid-April.
However, in the proposed plan, a much greater emphasis is placed on water exchange during the
drawdown. Impoundment water control structures are adjusted to allow frequent water exchange
during the drawdown and this allows the transient estuarine organisms present in early spring
access to the impoundments. Since impoundment salinities are typically at their lowest in late
winter/early spring, frequent exchange during this period also allows freshwater organisms, such
as sunfish and mudminnows, impoundment access during this period.
The third phase of the proposed management plan, beginning in mid-April and continuing
through August, has the same goals as the current plan but emphasis is put on providing maximal
estuarine exchange for estuarine organism impoundment access. Although impoundment water
levels remain at 50% pool during this phase except for the monthly floodings of the impoundment
surface, water exchange is frequent to allow estuarine organisms in and out of the impoundments
and prevent salinity increases. Water quality is a crucial factor in determining water exchange rate
as water quality, particularly dissolved oxygen, often drops to critical levels during this phase due
to high biological loads and high water temperatures (Clark, 1995). Water control structures
must be adjusted frequently during this phase to maintain both proper impoundment water levels
and adequate water exchange. Tests conducted on the Little Creek and Port Mahon impoundment
units during summer 1993 and 1994 demonstrated water levels can be maintained at any desired
level while providing nearly continual water exchange simply by adjusting the water control
structures in accordance with tidal heights (Clark, 1995). Basic water quality factors, such as
temperature, salinity, and especially dissolved oxygen, should be monitored frequently during this
phase to verify the water exchange rate is sufficient to maintain adequate water quality.
The final phase of the proposed plan, beginning in September and ending in early October,
is very similar to that of the current plan. The impoundments are flooded and drained several
times during this phase. The proposed plan differs from the current plan in, once again,
recommending that water exchange continue both during flooding and draining cycles and
between cycles.
A practical guide to impoundment management based on the proposed plan is difficult to
produce because of the variation in conditions faced during the year (e.g., variations in tidal
heights and amount of precipitation) by each impoundment and the differences in conditions
between impoundments (e.g., tidal height necessary to fill the impoundment). However, an
example of the proposed plan in practice can provide a comprehensive view of actual management
actions taken to meet the goals of the plan. While the Little Creek Impoundment (Little Creek
Unit A, Little Creek Wildlife Area, Little Creek, Delaware) was flooded and drained during
August 1994 to meet the revegetation goals of the current management plan, water exchange was
70
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continuous to allow unimpeded impoundment ingress and egress to estuarine organisms in
accordance with the proposed plan (Table 2).
LITERATURE CITED
Clark, J. H. 1995. Impoundment estuarine interactions. Federal Aid in Fisheries
Restoration Project F-44-R-5. Final report. Delaware Division of Fish and Wildlife,
Dover, Delaware. 186pp.
Whitman, W R. and R. V. Cole 1987. Ecological conditions and implications to
waterfowl management in selected coastal impoundments of Delaware, pp. 98-119 in
Whitman, W. R. and W. H. Meredith (eds.) 1987. Waterfowl and Wetlands Symposium:
Proceedings of a Symposium on Waterfowl and Wetlands Management in the Coastal
Zone of the Atlantic Flyway. Delaware Coastal Management Program, Delaware
Department of Natural Resources and Environmental Control. Dover, Delaware.
522 pp.
Whitman, W. R. 1991. A management strategy for restoration and maintenance of wildlife
habitat in high salinity coastal impoundments in Delaware. Unpublished report.
Delaware Division of Fish and Wildlife, Dover, Delaware. 118 pp.
Williams, R. K. 1987. Construction, maintenance, and water control structures of tidal
impoundments in South Carolina pp. 139-166 in Whitman, W. R. and W. H.
Meredith (eds.) 1987. Waterfowl and Wetlands Symposium: Proceedings of a
Symposium on Waterfowl and Wetlands Management in the Coastal Zone of the
Atlantic Flyway. Delaware Coastal Management Program, Delaware Department
of Natural Resources and Environmental Control, Dover, Delaware. 522 pp.
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Table 1. Summary of current and proposed management plans for high-level tidal impoundments owned by Delaware Division of Fish
and Wildlife.
Period
Current Plan
Proposed Plan
Mid-October
through
mid-January
Late January
to March
March 1 - March 15
March 16 through
mid April
Mid April through
August
September
through mid-
October
Impoundments filled to and maintained at
maximum level. Minimal water exchange.
Impoundments drawn down and reflooded as
needed to prevent ice from forming on
surface.
Impoundments filled and kept at maximum
level to ensure waterfowl do not choose
nesting sites in floodable areas.
Impoundments gradually drawn down to 50%
pool level. Some water exchange
permitted during high tides.
Impoundment water level maintained at
50% pool to allow maximum revegetation.
Salinity kept low by frequent water
exchange. Exposed impoundment surfaces
flooded and drained monthly to prevent
salinity buildup in surface soils.
Impoundments flooded to maximum and
drained to minimum levels once or
twice to remove excess nutrients,
distribute seeds, and stabilize soil.
Impoundments filled to maximum
level. Water exchange maintained during
period to allow estuarine organism access.
Same as current plan but water
exchange continued during drawdowns
and floodings.
Same as current plan.
Same as current plan but water
exchange continued throughout drawdown.
Impoundment water level maintained at 50%
pool to allow maximum revegetation. Exposed
impoundment surfaces flooded monthly to
prevent salinity build-up in surface soils.
Water exchange virtually continuous to allow
impoundment access to estuarine organisms
and prevent water quality degradation.
Water quality monitored to determine
exchange rates.
Same as current plan but water
exchange continued during drawdowns
and floodings.
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Table 2. Management actions taken to meet proposed plan management goals for the Little Creek Impoundment (Unit A, Little Creek Wildlife
Management Area, Little Creek, Delaware) during August 1994.
Management Goal Date/Tide Heights' Water Control Structure 1 2 Water Control Structure 23 Water ii
(Current & Proposed) (ft. above MLLW) River4
Flood Impoundment
to maximum level to
flush surface while
allowing maximum fish
access.
Maintain at flood level
for flushing while
allowing maximum fish
access
Drain to 50% surface
inundation while allowing
maximum fish access.
Maintain at 50%
surface inundation
while allowing maximum fish
access.
1/3.4,4.3
2/3.4,4.5
3/ 3.5,4.6
4/ 3.6,4.8
51 3.8,5.0
61 4.0,5.1
11 4.3,5.2
8/ 4.5,5.2
9/ 4.7,5.1
10/4.8,4.9
11/4.9.4.6
12/5.0
13/4.3,5.0
14/4.0,4.9
15/3.8,4.9
16/3.8,5.0
17/3.8,5.1
18/4.0,5.2
19/4.2,5.2
20/4.4,5.2
21/4.5,5.1
22/4.6,5.0
23/4.7,4.7
24/4.6,4.5
25/4.6,4.2
26/4.5
27/4.0,4.4
28/3.7.4.4
29/3.6,4.3
30/ 3.5, 4.4
31/3.5,4.5
Impoundment8 Creek4 Impoundment'
Open 2 Open
Open 5 Open
Open 7 Open
Open 7 Open
Open 7 Open
Open 3 Open
Water on Surface
(% FulH
(% Inundated)
10
100
100
50
80
100
100
100
100
60
70
50
60
50
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1 Tide heights for Breakwater Harbor, Lewes, Delaware. Tide heights in bold lettering were spring tides associated with the new and full moons,
however, during August 94 tides were higher than normal during the neap tide period of the first quarter (August 11 through 17).
2 Water control structure 1 connected the impoundment to the Little River, a small tidal tributary of Delaware Bay with moderate freshwater
inputs.
3 Water control structure 2 connected the impoundment to a small, unnamed tidal creek in the vicinity of Pickering Beach. This creek drained into
Delaware Bay and had little freshwater input.
4 The river/creek gates of the water control structures had two positions: open and closed. In the open position, tidal water flowed unobstructed
from the river/creek into the impoundment. In the closed position, the force of the tidal water sealed the gate shut and prevented water from
entering the impoundment. If the impoundment gate was open, water freely exited the impoundment whether this gate was open or closed.
s The impoundment gates of the water control structures had 12 settings, for this table a 0 setting would be folly closed and a 12 setting folly
opened. In the closed setting, water could not exit the impoundment while in the open settings water could exit the impoundment in varying
amounts corresponding to the gate setting. If the river creek gate was open, water freely entered the impoundment whether the impoundment gate
was open or closed. Tide height was the major factor in determining impoundment gate setting. For example, to allow impoundment surface drainage
while maintaining maximum water exchange in the ditches, the impoundment gate might be set at 3 for a neap tide but at 7 for a spring tide.
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RESEARCH AND MANAGEMENT NEEDS IN THE MID-ATLANTIC:
THE MID-ATLANTIC REGIONAL MARINE RESEARCH PROGRAM
Sherri Cooper
Mid-Atlantic Regional Marine Research Program
2200 Symons Hall, University of Maryland
College Park, MD 20742
Douglas Lipton
Maryland Sea Grant Extension Program
Department of Agricultural and Resource Economics
University of Maryland, 2200 Symons Hall
College Park, MD 20742
Merrill Leffler
Maryland Sea Grant
0112 Skinner Hall, University of Maryland
College Park, Maryland 20742
The Regional Marine Research Program
The Regional Marine Research Program (RMRP) was developed to provide support for
regional, management-driven research, addressing water quality and ecosystem health in the near
coastal oceans. The South Carolina Fish Hatchery Act of 1990, Title IV, Regional Marine
Research Programs (Public Law 101-593) established nine programs in coastal regions around the
nation. Each program is directed by an 11-member Board, and each is required to produce a
comprehensive research plan that contains: (1) a regional characterization; (2) an inventory of
existing research efforts; (3) an identification of research needs; (4) a strategy for coordination
with existing programs; and (5) a timeline. Given limited funding and increasing pressures placed
on the coastal oceans, a regional scale of coordinated planning and research into issues of land
use, geology, hydrology, biology, economics, and sociology is absolutely necessary to form
effective and efficient resource management. The nine regions designated by Public Law 101-593
are: Gulf of Maine, Greater New York Bight, Mid-Atlantic, South Atlantic and Caribbean, Gulf of
Mexico, Southwest, Pacific Northwest, Alaska, and Insular Pacific.
The Mid-Atlantic RMRP
The Mid-Atlantic RMRP encompasses the coastal and near-coastal waters between Cape
May, New Jersey and Cape Fear, North Carolina (Figure 1). This region is unique in its
preponderance of large estuaries that interact with the adjacent shelf area, its fishery resources,
and high local human population densities with steep demographic gradients. The goal of the Mid-
Atlantic RMRP is to conduct and foster integrative, regional research in the Mid-Atlantic region,
and to detect and differentiate changes in marine ecosystem function, integrity and health arising
from natural forces and human impacts. The program emphasizes the analysis of past effects and
improved understanding of system dynamics to project how changes in human demography and
land use affect the receiving waters, marine resources, and ecosystem integrity of the Mid-Atlantic
region.
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Population and Anthropogenic Influences
By conservative estimates, over half of the population in the United States of America
lives within fifty miles of the coast. Demographic projections in the Mid-Atlantic region indicate
that both the proportion and the size of this coastal population will increase significantly over the
next 50 years. Clearly, the environmental impacts of attendant development can be expected to
affect coastal waters negatively. The well known stresses to coastal waters include input of
pollutants from point and nonpoint sources, dumping of dredge spoils, loss of habitat (e.g.,
wetlands), spillage of petroleum products from offshore oil and gas extraction and trans-shipment,
and increased commercial and recreational fishing pressure, leading to the decline of important
fisheries. While some of the effects of these stresses are obvious, most are subtle and not well
understood, and it is often difficult to differentiate anthropogenic from natural, climate-induced
stresses.
Data Access for Management Decisions and Priority Research Needs
The Mid-Atlantic RMRP plan acknowledges the importance of methods and application of
research to management and planning. Regional research is most important in terms of regional
management. There is a need for more, and better, access to existing data and information on the
marine and estuarine ecosystems, that can be applied to management decisions, modeling of
ecosystems, and coordinated multidisciplinary research on basic processes. The inventory of
existing programs and projects within the region is extensive. The Mid-Atlantic RMRP plan
hopes to foster coordination of existing programs and efficient use of resources within the region.
The priorities determined for the Mid-Atlantic research plan were corroborated by managers
within the region via a survey conducted by the Mid-Atlantic RMRP
The following methods of research are considered high priority under this plan:
(1) Data management, synthesis and interpretation
(2) Ecosystem modeling and comparative studies
(3) Presentation and application of regional research to regional management
(4) Economic and social considerations.
The following specific scientific research areas are considered high priority for application of the
above methods:
(1) Historical and contemporary effects of land-use on living resources in the context of
ecosystem structure and function
(2) Eutrophication, algal blooms and anoxia
(3) Fishery yields, recruitment and trophodynamics of the Mid-Atlantic Bight
(4) Parameters of materials (including nutrients, sediments and contaminants) and biotic
exchanges between estuaries and the coastal ocean
(5) Coastal erosion and climatic effects.
The Mid-Atlantic Research Plan
The Mid-Atlantic Research Plan fulfills the requirements of the legislation described
above. It contains a description of the region, the criteria for regional research in the Mid-
Atlantic, and a timetable for achieving goals. In addition, a comprehensive inventory of marine
research related to water quality, ecosystem health and coastal processes within the Mid-Atlantic
region was compiled and analyzed (Table 1). The Mid-Atlantic RMRP Board (Table 2) approved
the use of this Research Plan as a framework for initial implementation. The Plan has been
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reviewed by the Executive Committee for the Regional Marine Research Program, and it has been
approved by both NOAA and EPA. Unfortunately, the Program will not be able to fund research,
as Congress has now cut funding; however, the Research Plan should serve as a useful model for
guiding priorities for future research in the Mid-Atlantic region for other programs, institutions,
organizations and agencies.
Land-use Workshop
Within the Mid-Atlantic Research Plan, the first priority research need for the region was
determined to be historical and contemporary effects of land-use on living resources, in the
context of ecosystem structure and function. To address this issue, the Mid-Atlantic RMRP
hosted a workshop in early December, 1994 entitled "Land-use effects on water quality in Mid-
Atlantic coastal waters and estuaries: management and research needs". A report produced by
Maryland Sea Grant about this workshop is now available, including a current understanding of
land-use effects on coastal waters followed by a listing of management information needs,
research recommendations, and regional planning and cooperation ideas. Workshop members
were in agreement that all watersheds and coastal waters in the region have been affected by land
use changes over time, including changes that result from population increase, development and
deforestation. In addition, they were in agreement over the following and other specific issues.
Land-use effects
• Not all estuaries and coastal waters respond to land use changes in the same way. Differences
are related to geology and geomorphology of the drainage basins, sediments, ground water
input, hydrology and residence time. These differences also relate to how each system will
respond to sea level rise and other climatic influences.
• Estuaries in the mid-Atlantic are linked in terms of near coastal Atlantic ocean circulation
patterns. Living resources that move between estuarine and near coastal waters are shared,
and there are exchanges of nutrients and toxic materials.
• If differences between systems can be quantified, then local systems and/or subsystems may be
used as models for other or larger systems. There is a need for more interdisciplinary work
combining upland, estuarine and coastal research, as well as economic and policy interests.
Management Information Needs
Managers need:
• Strong evidence that demonstrates specific successes and failures of scientifically-based
regulatory practices
• Predictive models that can relate land-use patterns and population density with the impact on
ecological functioning of aquatic systems (e.g., water quality and fisheries).
• Economic models that can be employed to predict land-use and development patterns.
• Integrated ecological and economic molds to explain how, under different regulatory regimes,
land-use decisions are made and the consequence of those decisions on the ecological
functioning of aquatic systems.
Research Recommendations
Research is needed on a regional level to support:
•, Synthesis of existing data across varied research disciplines (e. g., in terrestrial ecology,
aquatic science, and economics).
• Linkage of studies of upland terrestrial and aquatic habitats to estuarine and coastal waters.
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• Quantitative models that link landscape, land-use patterns and population density to their
affects on coastal environments.
• Quantitative studies on the contribution of urban and suburban development to water quality.
• Interdisciplinary studies that link terrestrial and aquatic research with economic and policy
issues.
Regional Planning and Cooperation
• Regional workshops should be organized to synthesize existing data and review case studies.
• Focused workshops that bring together upland and coastal scientists (with data) and managers
(with examples) would be useful in addressing specific issues.
Information Exchange
The number one priority research method that the Mid-Atlantic Research Plan
recommends for facilitating and coordinating multidisciplinary research in the region is data
management, synthesis and interpretation. To meet this goal and demonstrate what can be done
using existing technology, the program embarked on a series of activities related to information
transfer. First, a report was commissioned on Data Management in the Mid-Atlantic Region.
Second, electronic hypertext versions of the Research Plan (see Figure 2) including a searchable
database of over 500 projects and programs ongoing within the region (1992-1996) was
developed. Finally, these and other products were published on line via Internet; Maryland Sea
Grant has the responsibility of updating the Research Inventory.
A listing of the current products available from the Mid-Atlantic RMRP follows:
• Mid-Atlantic Research Plan (1994), prepared by Sherri Cooper & Douglas Lipton, 163 pp.
• Hypertext versions of Mid-Atlantic Research Plan and Research Inventory, developed by
Antech Systems, Inc.
• Data Management in the Mid-Atlantic Region (1995), prepared by Antech Systems, Inc., 30
PP
• Land-Use Effects on Water Quality in Mid-Atlantic Coastal Waters and Estuaries:
Management and Research Needs (1995), a workshop report prepared by Merrill Leffler,
Sherri Cooper & Douglas Lipton, 31 pp.
The reports and electronic versions are available via ftp and can be accessed at the following
addresses:
World Wide Web
Gopher server .
For more information or copies of products, write to: Maryland Sea Grant, 0112 Skinner Hall,
University of Maryland, College Park, Maryland 20742, (301) 405-6371.
The hypertext software and data management report were produced by Antech Systems, Inc.,
1716 Lambert Court, Chesapeake, Virginia, 23320, (804) 366-5385, email: .
78
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Table 1. Type of funding, location or project identified in the Total Percent
research inventory.
Primary funding agency
Federal Funds
Sea Grant Funds (DE, MD, NJ, NC, VA)
Federal and State Funds, joint (not Sea Grant)
State Funds
Federal and Research Institute Funds, joint (not Sea Grant)
State and Research Institute Funds, joint (not SG)
Research Institute only
Regional Initiative Funds
Location of research
Chesapeake Bay and tributaries
Delaware Bay
Albemarlc/Pamlico Sound and estuaries
Delaware Inland Bays '
Maryland coastal bays (including Chincotcague Bay)
Continental shelf
Barrier islands
Types of information needs identified in the plan
Data management (10), synthesis and interpretation (10)
Modeling projects (ecosystem 10, nutrient 8, economic 2)
Comparison studies of estuaries within the Mid-Atlantic region
Management oriented (fisheries 24, coastal 7, land use 6)
Economic and social considerations
Specific regional research priority areas identified in the plan
Land use effects on living resources
• Land use and nutrients
• Land use and management
• Total programs and projects involving land use
Eutrophication and nutrients (32), algal blooms (10) or anoxia (5)
• Nutrients and management
• Nutrient modeling
• Nonpoint source nutrients
Fishery yields, recruitment (25) and trophodynamics (9)
Material and biotic exchange between estuaries and coastal ocean
Coastal erosion (3) and climatic effects (8)
Other research areas listed in the inventory
Toxics and pollutants
Human health issues
Habitat (wetlands and marsh 31)
Living resources (fisheries 136)
Monitoring
Water quality
Ecosystem programs and projects
Physical and process-oriented programs and projects
Sediments and geochemistry
248
151
56
22
20
5
2
1
179
43
75
15
8
21
6
19
39
3
40
14
8
3
6
23
43
7
8
4
34
5
10
56
4
82
159
41
49
27
74
41
49
29.9
11.1
4.4
4
1
<1
<1
35
8.5
14.9
3.0
1.6
4.2
1
3.8
7.7
<1
7.9
2.8
1.6
<1
1.2
4.6
8.5
1.4
1.6
<1
6.7
1
2
11.1
<1
16.2
31.5
8.1
9.7
5.3
14.7
8.1
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Table 2. Mid-Atlantic Regional Marine Research Board of Directors
Christopher F. D"Elia, Chairman
Maryland Sea Grant Program
College Park, MD
Larry Atkinson
Old Dominion University
Norfolk, VA
Donald Boesch
Center for Environmental and Estuarine
Studies
University of Maryland
Cambridge, MD
Ford Cross
National Marine Fisheries Service
Beaufort, NC
J. Frederick Grassle
Rutgers Institute of Marine & Coastal
Sciences
New Brunswick, NJ
Norbert Jaworski
Environmental Protection Agency
Narragansett, RI
John Miller
North Carolina State University
Raleigh, NC
William Muir
Environmental Protection Agency Region III
Philadelphia, PA
William Rickards
Virginia Sea Grant Program
Charlottesville, VA
Jonathan Sharp
University of Delaware
Lewes, DE
Stuart Wilk
National Marine Fisheries Service
Highlands, NJ
Staff
Douglas Lipton, Executive Director
Sherri Cooper, Assistant Director
Dan Jacobs, staff
University of Maryland
College Park, MD
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Figure 1. Map of east coast of U.S. showing location of Mid-Atlantic region.
Gulf of Maine Region
Greater New York
Bight Region
Mid-Atlantic Region
South Atlantic & Garribean Region
Gulf of Mexico
Region
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Figure 2. Screen capture from the custom hypertext version of the Mid-Atlantic Research
Plan.
MARMRP Research Plan
Pie Edit Bookmark Jopic yiew Highlight Options Help
Introduction and characterization of
the Mid-Atlantic Region
The Mid-Atlantic region is a complex system. Large estuaries
interact with the large adjacent shelf area. The system is forced by
extreme seasonal variability, large rivers, strong winter storms and
'all hurricanes, and eddies spinning off the Gulf Stream. The
ecosystems depend on the complex interplay of the estuaries and
shelf systems. Economically important species routinely move
between the estuaries and shelf. Human impact is no doubt
significant, relative to natural variability, but quantitatively poorly
known.
The Mid-Atlantic region contains high local human population
densities and steep demographic gradients, with intense resource
utilization. Resources of the Mid-Atlantic coastal areas include
extensive fishery, recreational, mineral, shipping and commercial
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A HABITAT MANAGEMENT STRATEGY FOR THE OYSTER BAY/COLD SPRING
HARBOR-COMPLEX
Richard A. D'Amico
New York State Department of Environmental Conservation
Marine Resources Division
Bureau of Marine Habitat Protection
205 Belle Meade Road
EastSetauket,NY11733
The Long Island Sound Study (LISS) is concluding a project conducted under Section
301 of the Clean Water Act, the National Estuary Program. It involves Federal, State, Interstate,
local entities, universities, environmental groups, industry, and the general public. The Final
Comprehensive Conservation and Management Plan (CCMP) was completed in March 1994 and
approved in September 1994. The CCMP will, when implemented, improve the health of the
estuary while ensuring compatible human uses within the Sound ecosystem.
One of the actions called for in the Management and Conservation of Living Resources
and Their Habitats section of the LISS CCMP is for the New York State Department of
Environmental Conservation (NYSDEC) to develop a site-specific habitat management strategy
for the Oyster Bay/Cold Spring Harbor-Complex ("the Complex"). The habitat management
strategy for the Complex was initiated in late 1992 by NYSDEC in response to the area being
identified as a Regionally Significant Complex by the U.S. Fish and Wildlife Service's Northeast
Estuary Study.
The Complex consists of the drainages for and waterways of Oyster Bay, Mill Neck
Creek, Oyster Bay Harbor and Cold Spring Harbor. All of the waterways are embayments that
are part of a harbor-complex which drains into Long Island Sound. The Complex covers a total
of approximately 6,400 acres or 10 square miles. This includes:
• Oyster Bay Harbor, which consists of approximately 2,500 acres between the Bayville
Bridge and Plum Point on Centre Island;
• Mill Neck Creek, which is a tributary of Oyster Bay Harbor and covers approximately 300
acres;
• Cold Spring Harbor, which consists of the waterway landward of Cooper Bluff in Cove
Neck and West Neck Beach in Lloyd Harbor, which includes approximately 1,360 acres;
and,
• Oyster Bay, which consists of approximately 2,240 acres between Centre Island and the
Lloyd Neck Peninsula.
The Complex, although it contains some areas that have been developed, also includes
significant natural areas. These natural areas contribute to the quality of life enjoyed by residents
and visitors to the community. The preservation of the environmental quality of the Complex is
essential to the continued enjoyment of activities such as boating, fishing, swimming and
sightseeing. In addition, the Complex supports a highly productive oyster industry; the majority
(up to 95%) of New York State's Eastern oyster crop is harvested there. Degradation of
environmental quality in the Complex would invariably result in restrictions and reductions in
these activities. The strategy, which was produced through consensus with federal, State and
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local government agencies, industry, and citizen's groups, provides recommended actions that will
enhance, protect and preserve the natural resources within the Complex.
Vegetated tidal wetlands constitute some of the most productive and biologically valuable
habitat within the Complex. Most of the shoreline within the Complex contains intertidal or high
marsh areas, or both. There are interruptions to the continuity of wetlands along the shore of the
Complex, generally due to man-made structures. Based on NYSDEC tidal Wetlands Maps, there
are approximately 400 and 160 acres of intertidal and high marsh, respectively, within the
Complex, with the largest areas typically occurring in the headwater portions of embayments.
As with vegetated tidal wetlands, the largest areas of tidal flats are generally located in the
headwaters of embayments, particularly in Cold Spring Harbor, which has the greatest tidal range
of any embayment in Long Island Sound (frequently in excess of eight feet). Large areas of tidal
flats are also located adjacent to topographic and structural features that interrupt sediment
transport within an area (e.g., groins, jetties, reefs). Based on NYSDEC Tidal Wetlands Maps,
there are approximately 640 acres of nonvegetated intertidal land within the Complex.
Due to the relatively low wave energy within the Complex, most of the beach areas within
the Complex are narrow, as compared to beaches directly on Long Island Sound. The continuity
of beach area within the Complex is somewhat less regular than the tidal wetland and tidal flat
zones.
Dunes are limited in distribution within the Complex. Dunes primarily occur on, the
eastern shore of Cold Spring Harbor, along Lloyd Neck and the Sand Hole.
Bluffs, although irregularly distributed, occur throughout the Complex. Most bluff areas
are well-vegetated, and therefore, relatively stable.
There are ten tributary or subtributary streams in Suffolk County that drain into the
Complex. In Nassau County, 25 tributary and subtributary streams and ponds are within the
drainage of the Complex. All of the freshwater tributaries in the Complex are at a minimum
classified as being suitable for fish propagation and survival, and are generally fit for secondary
contact recreation. Several streams are capable of supporting cold-water fish species, including
the only stream in Nassau County known to support a naturally reproducing brown trout
population.
There are over 360 acres of NYSDEC mapped freshwater wetlands in the Complex. All
freshwater wetlands in the Complex are either type I or type II, which are the two most valuable
classifications.
Riparian areas are defined as vegetated land along a waterway through which energy,
materials, and water may pass. They are found along most of the waterways and tributaries in the
Complex.
Human activities in the Complex include: industry, transportation, fishing, shellfishing,
hunting, swimming and boating. Some of these activities have caused or contributed to problems
within the Complex:
• contamination with pathogens;
• contamination with toxics/petroleum compounds; and,
• habitat loss and destruction.
Currently, habitat within the Complex is protected by laws at the federal, State, and local
level. For example, with New York State's passage of the Tidal Wetlands Act in 1973, losses of
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vegetated tidal wetlands within the Complex have been minimized, and these areas should be
preserved in perpetuity.
In formulating a management plan for the Complex, the following objectives have been
identified:
• reduction of pollutant and nutrient loadings to the waterways;
• restoration and enhancement of important commercial and recreational species of living
marine resources and the habitats that support them;
• increase public awareness of the value of the Complex and how it is impacted by human
activities; and,
• implementation and enforcement of laws and regulations to ensure protection of the
complex.
Any management strategy for the Complex should consider the entire watershed. Therefore,
some of the actions proposed will include upland and freshwater areas within the drainage of the
waterways of the Complex.
In developing actions to reduce pollutant and nutrient loading to waterways, chemical
contaminants, pathogens and substances required to support the growth of phytoplankton were
considered. LISS determined that excess nitrogen contributes to reduced dissolved oxygen levels
by fueling excessive growth of phytoplankton in Long Island Sound.
Nonpoint sources are the major source of pathogen contamination (as well as a significant
cause of nutrient loadings) in the Complex, and therefore, most of the actions to reduce pollutant
loadings to the waterways will be focused on nonpoint sources. Vegetative controls for runoff
include installation of vegetated filter stripping seaward of a parking area at Centre Island.
Creation of an intertidal marsh is another vegetative runoff control device proposed in the
strategy. Structural controls include diverting stormwater outfalls to retention areas or away from
locations of the Complex with poor flushing characteristics.
In order to implement best management practices for controlling pathogen contamination
from stormwater, it is necessary to determine the sources of the loadings. Track-down surveys
will provide this information.
Local governments should implement storm drain stenciling programs. This will help to
educate the public not to dispose of contaminants in storm drains.
Actions to enhance living resources include:
• identify and seek to restore areas where wetland degradation has taken place;
• create a "no-wake" zone within 150 yards of shore along the Oyster Bay National Wildlife
Refuge, and,
• institute a vegetative buffer zone 100 feet landward from streambanks of any waterways
that are known to support naturally reproducing trout populations.
Other management actions to address issues of public access, floatable debris, and public
involvement include:
• determine optimum frequency for catch basin and street cleaning to decrease floatable debris
reaching waterways;
• encourage participation in the National Beach Cleanup Program;
• consider addition of a parking area near Mill Pond to increase public fishing access; and,
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investigate the possibility of creating a marine education center at the recently remediated
Jakobson Shipyard facility.
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USE OF DREDGED MATERIAL FOR THE CREATION OF EELGRASS HABITAT ON
AN UNDERWATER TERRACE
Ryan Davis and Frederick T .hort
Department of Natural Resources
Jackson Estuarine Laboratory
University of New Hampshire
Durham, NH 03824 (603)862-2175
ABSTRACT
Eelgrass (Zostera marina L.) habitats are an important estuarine resource and provide
critical functions such as shelter, foraging areas, sediment stabilization, water quality
enhancement, and nurseries for economically and ecologically important species. Eelgrass was
transplanted eelgrass into the Piscataqua River on the Maine\New Hampshire border to mitigate
for impacts to an eelgrass bed incurred by a port expansion project. Additionally, to create new
habitat where it previously did not exist, an underwater terrace was constructed to provide
acreage within the photic zone and depth range required by eelgrass for survival and expansion.
The 0.75 acre terrace was constructed by placing a riprap wall in the river to act as a containment
barrier and backfilling the area with material dredged from a coastal harbor. The terrace was then
transplanted with eelgrass on 0.5 m intervals in the summers of 1994 and 1995. While the terrace
did bury existing substrate and benthic habitat, the created eelgrass habitat will provide far greater
functional values than the mud bottom it replaces. To demonstrate this, the site will be monitored
for the next 15 years to assess functional values such as primary production, habitat complexity,
fish use and benthic species diversity. The construction of underwater terraces provides a
beneficial use of dredge spoil material and creates habitat of high functional value.
INTRODUCTION
Compensatory mitigation for impacts to natural resources by restoring or creating habitats
has been practiced for over a decade. However, compensatory mitigation, which is authorized
under Section 404 of the Clean Water Act, is only allowed once all other efforts to avoid or
reduce impacts have been exhausted (Code of Federal Regulations, 1993). The act requires that
for any project which will result in dredge or fill material being placed in the waters of the U.S.,
the developer expend all reasonable effort to first avoid, then reduce, and finally mitigate for, any
negative impacts to natural resources (Code of Federal Regulations, 1993). Mitigation is not only
intended to replace the actual areal extent of the lost or damaged resource, but is also an attempt
to replace the functions and values of the impacted area (Federal Register, 1990). There are two
methods by which functions and values can be replaced: the restoration or enhancement of an
existing similar resource or the creation of entirely new habitat. While the former is generally
easier to accomplish, the latter is considered true mitigation and is preferred by regulatory
agencies. Both of these methods were used to replace the functions and values of several habitats
that will be impacted by a port facility expansion project in New Hampshire.
The New Hampshire Port Authority Expansion Project currently taking place in
Portsmouth, NH, involves construction of expanded pier facilities and includes dredging and
filling within the estuary. Because no other area was available, the project will directly and
indirectly impact salt marsh, mudflat, and eelgrass habitats which currently exist at the site.
Engineering and design changes were first used to reduce overall project impacts on these
estuarine resources Once the final construction plans were approved, a comprehensive
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Mitigation Plan was created which specified the restoration and creation of salt marsh, mudflat,
and eelgrass habitats to mitigate for the remaining impacts associated with the project (Balsam et
al., 1993).
From 1993 to 1995, 6.2 acres of eelgrass were transplanted on the New Hampshire side of
the Piscataqua River, the largest and most northerly eelgrass mitigation on the east coast. The 6.2
acres are designed to replace the functions and values of 4 acres of eelgrass habitat that will be
impacted by the construction and operation of a new pier. The number of acres being
transplanted is greater than that impacted because of the uncertainty of eelgrass transplanting
success and because it will take some time for the transplanted eelgrass to create well developed
beds. Eelgrass beds provide critical functions such as shelter, foraging areas, and nurseries for
economically and ecologically important species as well as sediment stabilization and water
quality enhancement (Thayer et al., 1984).
Approximately 5.45 acres of eelgrass were transplanted in existing subtidal mudflat areas
which historically supported eelgrass. However, the Mitigation Plan required the creation of 0.75
acres of eelgrass habitat. An underwater terrace was constructed to create bottom acreage within
the photic zone suitable for transplanting eelgrass (Figure 1). The 0.75 acres constitutes the
creation of new eelgrass habitat where it previously did not exist to mitigate for the permanent
loss of habitat resulting from port construction.
The construction of underwater terraces has been used in the past for the creation of
estuarine habitat. For example, a terrace was built to provide foraging habitat for juvenile salmon
in the Duwannish River estuary near Seattle, Washington (Simenstad & Thorn, 1992). Terraces
were also used to create eelgrass habitat in San Diego, California (Merkel and Hoffman, 1990)
and were proposed as a mitigation option in Drayton Harbor, Washington (Simenstad & Thorn,
1992).
TERRACE CONSTRUCTION METHODS
The terrace was constructed by placing large stone (60 cm mean diameter riprap) parallel
to the shoreline and perpendicular to existing rock outcroppings to create three sides of a
rectangular containment wall. The 110 meter long wall is approximately 1.75 meters high and
was constructed along the -3.5 meter mean low water (mlw) contour. The enclosed area was
then filled with estuarine sediments (sandy mud) to raise the bottom elevation to within the photic
zone required by eelgrass (-0.6 to -2 meters mlw). Prior to placing riprap on the river bottom, a 4
oz. non-woven geotextile filter was laid down to stabilize the bottom and prevent the riprap from
sinking into the substrate. The tarp was held on the bottom by a number of 3 meter sections of
6.5 cm diameter wire cable attached along the length of the tarp. Beginning in January 1994,
riprap was loaded from the adjacent shoreline onto a barge using a land-based crane. The barge
was towed to the terrace location and a barge-based crane placed the riprap on top of the tarp.
Construction of the riprap wall took approximately five weeks.
The fill needed for construction of the terrace was obtained from a dredge disposal area
located on Awcomin Marsh in Rye, New Hampshire. In the past, dredge material from Rye
Harbor was deposited on this salt marsh. Salt marsh restoration required removal of the dredge
spoil and use of this dredge material for terrace construction provided an environmentally and
economically favorable disposal option. Beginning in March 1994, sediment was trucked to the
construction site and loaded onto a 92 cubic meter dump scow using a front end loader and a
land-based crane. The full dump scow was towed to the terrace site and dumped. Approximately
3,680 cubic meters of material were placed over a four week period. The sediment was allowed to
consolidate for three months prior to transplanting with eelgrass.
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TERRACE HABITATS
The finished bottom elevations inside the riprap wall are -0.6 to -2 meters mlw which is
consistent with that of the naturally occurring eelgrass beds nearby in the Piscataqua River. Light
intensity at the terrace ranges from 800 -. 1200 pE per m2 compared to 550 -1300 pE per m2 at
the adjacent natural beds. Transplanting onto the constructed terrace began in mid-June, 1994.
The terrace was divided into 10m x 10m plots. Planting grids constructed of PVC pipe and nylon
line were placed within the plots to facilitate planting on 0.5 m intervals. Planting units, which
consist of two eelgrass plants aligned in opposite directions, were anchored into the sediment
using bamboo skewers bent in half. Overall, 14,440 eelgrass plants were transplanted in June and
July, 1994, approximately 40% of which survived and were growing as of spring 1995. An
additional 3,000 plants were transplanted in June, 1995. Field sampling was conducted in August
1995 to determine aboveground biomass and density of the transplanted eelgrass (Figure 2).
Eelgrass densities on the terrace were 75% of the control, although biomass was only 25% of the
control.
In addition to the eelgrass habitat created, the large stone used to build the containment
wall is expected to increase primary and secondary production by providing an attachment site for
a variety of macroalgae (e.g., Laminaria spp.) and creating high quality habitat for lobsters
(Homants americanus), crabs (e.g., Cancer irroratus), and fish (e.g., Cyclopterus lumpus,
Hemitripterus americanus). Three months after the terrace was completed, a preliminary lobster
survey of the terrace using the transect method showed lobster population densities as high as 1
per 40 m2. This compares favorably with the results of a previous study which determined lobster
densities in cobble substrate and mudflats to be 1 per 10m2 and 1 per 75 m2, respectively (Cobb,
1971). A lobster survey conducted 17 months after terrace completion found lobster densities to
be 1 per 18 m2 We will continue to sample the lobster population yearly and expect that lobster
densities will increase as the eelgrass bed becomes more established and prey items more
available
CONSTRUCTION AND PLANTING COSTS
The total cost for constructing and transplanting the underwater terrace, including all
project planning, management and first year monitoring was $239,000. The cost for terrace
construction, including tarp, riprap, and sediment placement was $190,000. Transplanting,
including harvesting and planting eelgrass using SCUBA divers cost $49,000. The total cost was
partially dependent on the environment in which the terrace was created. The Piscatqua River is
characterized by strong tidal currents and a large tidal amplitude (over 3 meters spring tides).
These conditions limited the amount of time available for construction and/or planting operations
each day. Costs for constructing terraces in more quiescent environments would tend to be
lower.
CONCLUSION
The constructed terrace created a site within the photic zone for eelgrass habitat where
none had previously existed. While the cost for constructing the terrace may seem high, it must
be remembered that the creation of new habitat is the only acceptable mitigation alternative for
the permanent loss of critical estuarine habitat. The underwater terrace provides a unique
approach for using dredge spoil material to migitate for impacts and improve estuarine resources.
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LITERATURE CITED
Balsam Environmental Consulting, Inc., Jackson Estuaririe Laboratory, Great Meadow
Farms. 1993. Mitigation Plan for the New Hampshire Commercial Marine Terminal
Development Project in Portsmouth, New Hampshire. 98 pp.
Cobb, J.S. 1971. The shelter-related behavior of the American lobster, Homarus americanus.
Ecology 52:108-115.
Code of Federal Regulations. 1993. 40 CFR 1508.20. Mitigation and 33 CFR 320.4(r).
Mitigation.
Federal Register. 1990. Memorandum of Agreement (MOA); Clean Water Act Section
404(b)(l) Guidelines; Corrections. Federal Register 55 (48): 9210-9213. Monday,
March 12, 1990.
Merkel, K.W. and R.S. Hoffman. 1990. The use of dredged materials in therestoration of
eelgrass meadows. A Southern California perspective. In: Landin, M.S. et al. (eds.),
Proceedings of a Regional Workshop: Beneficial Uses of Dredged Material in the
Western U.S., May 21-25, 1990. San Diego, Ca. U.S. Army Corps of Engineers,
Waterays Experiment Station, Vicksburg, MS.
Simenstad, C.A. and R.M. Thorn. 1992. Restoring Wetland Habitats in Urbanized Pacific
Northwest Estuaries, p. 423-472. In G.W. Thayer (ed.), Restoring the Nations
Marine Environment. Maryland Sea Grant College. College Park, Maryland.
Thayer, G.W., W.J. Kenworthy and M.S. Fonseca. 1984. The ecology of seagrass meadows
of the Atlantic Coast: a community profile. U.S. Fish and Wildlife Service,
FWS/OBS-84/02. 147 p.
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HIGH TIDE
-LOW TIDE
OPTIMAL
EELGRASS DEPTH
Original Slope
«
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Figure 2. Eelgrass biomass (g/m2) and density (shoots/m2) at the underwater terrace and an
adjacent naturally occurring eelgrass bed (control) at the end of the second growing season.
Standard errors (not shown) for the terrace are .749 (biomass) and 2.095 (density). Standard
errors for the control are 1.317 (biomass) and 1.452 (density).
Eelgrass
at terrac
120
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JET-SPRAY®1 THIN-LAYER OVERLAYS OF DREDGED MATERIAL
FOR WETLANDS REHABILITATION AND CREATION
Troy Deal
Aztec Development Co.
1331 W Central Blvd
Orlando, Florida 32805
ABSTRACT
Subsidence, increasing sea-level elevations, and human intervention have accelerated
deterioration and loss of saltwater marsh and wetlands originally created and maintained by
nature's flood-ebb thin-layer material placement cycles.
Dredged material now disposed into containment ponds or berms can better be used to
rehabilitate and maintain existent marsh and wetlands or to create new wetlands in shallow water
environments from similar natural thin-layer overlays using JET-SPRAY® aerially-sprayed
continuously-moving placement techniques. JET-SPRAY® techniques convert undesirable
dredged material "spoil" into valuable beneficial <5-cm to 8-cm (2" to 3") layered overlay material
for cost-effective marsh and wetlands maintenance, restoration, or construction.
Additional JET-SPRAY® placement benefits are minimization of particle segregation
common to pipeline placements and elimination of environmentally hazardous and expensive
pipeline and heavy equipment.
Twenty-five years of numerous successful and environmentally superior placement
projects have won JET-SPRAY® acceptance from national regulatory agencies, but state
regulators have been slow to accept JET-SPRAY®'s technological innovations primarily because
of historically proven bureaucratic resistance to change.
INTRODUCTION
A National Research Council (NRC) Study Report on Restoring and Protecting Marine
Habitat states that "Institutional, regulatory, and management policies are the principal barriers to
wider and best use of technologies in marine habitat management." It also states, "The
current regulatory processes lack the flexibility in decision-making [sic] that is necessary to foster
innovative solutions" (NRC, 1994 cited in Sands and Young, 1994). This NRC Study calls for
removal of "procedural barriers through advancing the state of practice of marine habitat
restoration" (Sands & Young, 1994), and "calls on the Corps of Engineers' [sic] to revise its
policies" for "use of dredged material as a habitat-restoration resource, even when its use is more
expensive than disposal in the least costly environmentally acceptable manner" (Sands & Young;
1994). This report also advises that "the rapid placement of suitable dredged material at
appropriate locations and elevations in an estuary or delta approximates natural deposition and
can be an important, but notexclusive, element of a marine habitat restoration project" (Sands
& Young, 1994).Mathiesreports that the U.S. Army Corps of Engineers' regulations
designated as "Federal Standard" require dredge material placement method selections to
represent "the least costly" alternatives "consistent with sound engineering and environmental
standards," but that "beneficial use alternatives . are rarely the least costly alternatives
'JET-SPRAY® is a Registered Trademark and is protected by U.S. Patents Numbers 4 759,664;
4,896,445; 3,971,148; 5,167,469, 5,211,511; 4,628,623; 4,434,943; 4,575,960; 4,517,754;
4,240,243; and 4,521,305 (other and foreign patents pending). U.S. Patents are insured by The
Homestead Insurance Company for Patent Infringement and Abatement Insurance
2Chairman/Owner, AZTEC DEVELOPMENT CO., 1331 W Central Blvd, Orlando, FL 32805.
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and are therefore inconsistent with the 'Federal Standards'" criteria of the Corps of Engineers
(Mathies, 1994). Authority and funding to exceed "Federal Standards" is being sought and must
be obtained to provide a solution for beneficial use of dredged material (Mathies, 1994). Rozas
and Zimmerman report "the technology for creating marsh characteristics and features that are
functionally equivalent to natural marshes is only rudimentarily developed," and they also report
that "if marshes that are functionally equivalent to natural marshes can be constructed, the
increased benefit of enlarging the habitat area for fishery and forage species that use marsh •
systems should outweigh the loss of open bay habitat" (Rozas & Zimmerman, 1994).
A BETTER WAY TO BENEFICIALLY PLACE DREDGED MATERIAL
Cahoon and Cowan (1988) report substantial scientific documentation that fully confirms
the tremendous economic and social cost of the present ongoing loss of wetlands through
subsidence, increasing sea level elevations, and especially human interventions.
Many references prove that remediation, restoration, maintenance, and creation of
wetlands by dredged material placements as presently practiced using levees to contain pipelined
hydraulically placed overlays result in material segregation at the pipeline discharge (Cahoon,
1992, videotaped interview). The resulting nonhomogeneous material also requires heavy marsh-
destructive equipment to obtain critical elevations and build necessary dewatering structures.
Pipelines must be continuously moved, and hand or mechanical planting is especially destructive
on new soft marsh. The containment berms by definition cause artificial and nonnatural water-
marsh interface slopes (Cahoon, 1992, videotaped interview).
Wetlands, and particularly saltwater marsh, have been well established as one of the
world's most diverse and ecologically important habitats (Cahoon, 1992, videotaped interview).
This habitat and its vegetation and creatures has evolved by adapting to nature's natural, thin-layer
material overlay placements through eons of flood-ebb cycles. Cahoon advises (1992) that JET-
SPRAY® provides a means of imitating nature's thin-layer dredged material overlays when used
to strengthen and nourish existent marsh, convert shallow water to new marsh, invigorate existing
vegetation, and allow easy adaption of animal life without the need for destructive heavy
equipment, etc. Simply put, nature places marsh material in thin-layer increments and has adapted
to that placement. JET-SPRAY® exclusively imitates these natural placements while also
eliminating the destructive side-effects to the marsh of other placement systems (EPA, 1992).
Thus, destructive side-effects common to alternative placement means are avoided by JET-
SPRAY® (Cahoon, 1992, videotaped interview), and JET-SPRAY® placements are a better
way to beneficially place dredged material.
WHAT IS JET-SPRAY®?
JET-SPRAY® is a new and patented proprietary method for aerial placement of well-
slurried dredged material in thin layers of approximately 5 cm (2") or less onto existing marsh,
new marsh construction, or conversion of shallow water to emergent estuarine wetlands by
spraying material in 75-100 m (250-350') wide swathes using horizontally and vertically moveable
and controlled directional nozzles. For proper results, JET-SPRAY® techniques require
stringent supervision and training, and, therefore, the system is only available through trained
selected practitioners and is protected by Insured Current Patents and "Patents Applied For."
HOW CAN JET-SPRAY® BEST BE USED FOR HABITAT ENHANCEMENT?
According to EPA literature (1992), JET-SPRAY® techniques provide the only means
yet identified for placement of dredged material over large areas of existent soft marsh. This
literature also describes JET-SPRAY®'s latest development of wide-area, thin-layer placement
techniques such as: the JET-SPRAY® manifold-retracting reel sprayhead system, JET-
SPRAY®^ mobile-mounted sprayheads used in conjunction with large retracting reels, JET-
SPRAY®^ cable-moved sprayheads and pipelines, and various other movement schemes to move
sprayheads over large areas. These additional wide-area techniques for thin-layer placements
provide the means to deposit, with minimum disturbance, large quantities of dredged material in
thin-layer overlays over large areas. At present, no other system has been developed that
provides this unique capability for beneficial material disposal onto existing soft marsh with
virtually no noticeable destruction to the ecosystems (EPA, 1992).
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Cahoon and Cowan (1988) report that JET-SPRAY®, because of its aerially placed thin-
layer overlays and directed placements, can convert shallow water to new marsh, build islands,
and fill marsh voids without containment structures, while at the same time providing accurate
elevation control. The destructive effects of heavy equipment on soft marsh are avoided, and
ongoing bid results prove that marsh built using JET-SPRAY® techniques can be less costly than
other means (Bowman, ed., 1991).
It would appear that the use of JET-SPRAY®'s "stand-off1 placement capability could
allow marsh and nearshore berm construction in shallow water environments either from onshore
positions or from larger draft stand-off vessels (Bowman, ed., 1992). Construction of unconfined
islands or marsh should be easily accomplished, and material should be easily placed where it is
needed without rehandling. This "stand-off1 placement ability combined with JET-SPRAY®'s
accurate elevation control should be especially useful for erosion, water-land interface, and
estuarine remediation (Author's observations from actual experience).
It would also seem that JET-SPRAY®, through hydroseeding techniques during dredged
material final thin-layer placements, could revegetate and repopulate existent vegetation for better
food sources, protective habitats, and vegetative species control (Author's observation through
experience).
Actual projects (Lake Harris, 1984; and City of Savannah Project-Bowman, ed., 1993)
show JET-SPRAY® placements into wooded and vegetative wetlands do not require tree
removal or vegetation clearing, and there is no need for destructive heavy equipment on the
wetlands. Berms are eliminated, and flowback is minimized (AZTEC DEVELOPMENT CO.,
1992 and 1993, Video).
HOW IS JET-SPRAY® USED WITH DREDGES?
JET-SPRAY® thin-layer placements can be made using on-board moveable gun-nozzles
from any properly equipped conventional cutterhead suction dredge, or from pipelines to movable
monitor-nozzles at remote locations using auxiliary barge or mobile equipment. Retracting
pipeline reels at these remote locations can facilitate nozzle shifting and pipeline handling.
JET-SPRAY®'S ENVIRONMENTAL ADVANTAGES
By eliminating containment ponds JET-SPRAY® eliminates all the problems of pond
ownership, permitting, maintenance, and ecological changes, and also eliminates long-distance
pumping plus access destruction required for pipelines to suitable containment areas.
Cahoon (1992) and Wilber (1992) report that JET-SPRAY® when applied in thin-lift
overlays of 5 cm (2") or less nourish and strengthen marsh and wetlands by imitating the
continuing renewal overlay processes of nature without changing waterflow patterns, plant
species, or lifeforms (Wilber, Luczkovich, & Knowles, 1992).
Actual projects show that JET-SPRAY® techniques allow thin-layer disposal of dredged
materials with their nourishing effects into wetlands without destruction of trees or existing
vegetation as required by conventional heavy equipment techniques (AZTEC DEVELOPMENT
CO., 1992 and 1993, Video; Bowman, ed., 1993).
In weed control, actual projects show the WATER-WEEDER® version of JET-
SPRAY® techniques chop, slurry, and spread weed fibers over large areas in thin-layer overlays,
where they quickly dry to small fiber remnants (Greater Orlando Aviation Authority, 1983). This
large area thin-layer weed disposal reduces the bacteria and insect breeding common in decayed,
stacked, concentrated, organic piles experienced with conventional harvesting point stacking
techniques. Actual completed projects prove JET-SPRAY®'s WATER-WEEDER® can also
remove rooted weeds and underground tubers during weed harvesting to provide longer-lasting
results (Padera, 1979). Since JET-SPRAY®'s WATER-WEEDER® removal techniques are
mechanical and done without water-poisoning chemicals at speeds far in excess of conventional
mechanical harvesting methods, costs can be competitive with chemical control (Padera, 1979).
JET-SPRAY®'S COST ADVANTAGES (OBTAINED FROM ACTUAL JOB RESULTS)
JET-SPRAY® techniques eliminate high-maintenance, labor-intensive, time-consuming
pipeline costs, containment pond acquisition costs, construction costs, and ongoing maintenance
95
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costs. Also eliminated are area-consuming berms and flowback experienced with these elevated
berms, clearing of trees and vegetation from old established berms and equipment access, as well
as costly long-distance pumping to upland disposals.
JET-SPRAY® spudless/anchorless techniques allow high-speed straight-ahead
excavation of thin, narrow, face cuts, where rapid forward movement is required to obtain
low-cost volume production~and this is not possible with the pipeline-handling/ground-contact
restrictions common to other systems. Mobilization and set-up costs, labor costs, and capital
investment costs are reduced. Equipment is easily moved between shoals without pipelines or
containments. JET-SPRAY® techniques from pipelined remote barge or mobile platforms can
provide cost-effective shallow water marsh construction, mitigation, and oftentimes reduce
pipeline transfer costs.
JET-SPRAY® DISADVANTAGES
FROM EXPERIENCE OVER NUMEROUS PROJECTS
JET-SPRAY® techniques require trained operators and careful supervision in order to
provide desired results. Improper applications can be environmentally destructive, and carefully
enforced supervision and training control is the basic reason for the Licensing Program for JET-
SPRAY® applicators now underway.
JET-SPRAY® works best with easily slurried materials, and is assisted by pre-screening
and removal of oversized, nonslurrying debris and rock when present. High winds can cause
unwanted dispersal problems and shorten available disposal areas.
JET-SPRAY®, as is common to all hydraulic dredging, is not cost-effective in heavy clay
or other nonslurrying materials.
QUESTIONS AND ANSWERS (AUTHOR'S TO READER)
The Louisiana Sea Grant Program reports that" such state and federal regulatory
agencies as the Louisiana Department of Natural Resources, the U.S. Army Corps of Engineers,
the U.S. Fish and Wildlife Service, and the National Marine Fisheries Service consider spray
disposal the primary alternative to conventional bucket dredging" (Louisiana Sea Grant, 1987). If
JET-SPRAY® is cost-effective, as previously described, and if JET-SPRAY® accomplishes, in
a superior manner, the stated national goals of marsh and wetlands habitat restoration,
maintenance, and construction—why, after more than 25 years since JET-SPRAY® was
developed, is Louisiana, at present, the only state which classifies JET-SPRAY® techniques as a
normal and accepted dredged material placement method without special permitting (State of
Louisiana, 1993)~and why do some states such as Virginia, Georgia, and South Carolina actually
forbid marsh enhancement or marsh nourishment placements of any kind? Isn't it true that history
has proven that a dedicated establishment defending status qua is the greatest impediment to
technological progress? After 25 years of numerous, all successful, and nondestructive
environmentally superior JET-SPRAY® placements and national regulatory acceptance, why
should JET-SPRAY® placements still require special permitting or be refused by state
regulators? For the answer, please see the introduction to this paper referencing the National
Research Council Study describing regulatory barriers and inflexible management practices. It is
apparent for there to be progress in beneficial dredged material placements on existing marsh or
into shallow water environments using today's advancements; state regulators must move beyond
past practices and regulations based on yesterday's obsolete technology.
96
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REFERENCES
Aztec Development Co. 1992 and 1993. Project Video: JET-SPRAY® Aerial Placement of
Dredged Material. Featuring JET-SPRAY® Thin-Laver Placements on Saltwater Marsh
and Freshwater Hardwood Wetlands [Projects include: Mississippi Delta (1992), City of
Savannah (1993), and Hyde County, NC (1982)]. Moxie Media, Inc., New Orleans, LA.
Bowman, Ron, ed "Atchafalaya Bay Maintenance Dredging." World Dredging Mining &
Construction, September 1991, p. 6.
Bowman, Ron, ed. "City of Savannah's 14-Year Environmental Problem Solved." World
Dredging Mining & Construction [Special Focus: Environmental Benefits of Dredging].
August 1993, US ISSN 1045-0343, Vol. 29, No. 8, p. 6.
Cahoon, Donald R. and Cowan, James H. Jr. 1988. "Environmental Impacts and Regulatory
Policy Implications of Spray Disposal of Dredged Material in Louisiana Wetlands." Coastal
Ecology Institute, Center For Wetlands Resources, Louisiana State University. Coastal
Management. Vol. 16, pp. 341-362.
Cahoon, Donald R. (USFWS). 1992 Videotaped interview. Jn AZTEC DEVELOPMENT CO.
1992 and 1993. Project Video: JET-SPRAY® Aerial Placement of Dredged Material.
Featuring JET-SPRAY® Thin-Layer Placements on Saltwater Marsh and Freshwater
Hardwood Wetlands. [Projects include: Mississippi Delta (1992), City of Savannah
(1993), and Hyde County, NC (1982)]. Moxie Media, Inc., New Orleans, LA.
Lake Harris-Fox Run JET-SPRAY® Project. 1984. Clean Access Channel, Cypress Creek,
Mr Harold Holland, Leesburg, FL.
Greater Orlando Aviation Authority. 1983. WATER-WEEDER® Project for Orlando
International Airport, Orlando, FL.
Louisiana Sea Grant, Louisiana State University. "Spray Disposal: An Alternative for Louisiana's
Marshes?" Aquanotes. September 1987, USPS 933-920, Vol. 16, No. 3., pp. 1-4.
Mathies, Linda Glenboski. 1994. "Beneficial Uses of Dredged Material: Part of the Solution to
Restoration of Louisiana's Coastal Wetlands." In Vol. 1 of Dredging '94r Proceedings of
the Second International Conference on Dredging and Dredged Material Placement. Edited
by E. Clark McNair, Jr. New York: American Society of Civil Engineers.
National Research Council (NRC). 1994. Restoring and Protecting Marine Habitat: The Role of
Engineering and Technology. Report of Marine Board, National Research Council:
Washington, D.C.: National Academy Press. [Cited by reference In Sands and Young,
1994].
Padera, C. Evaluation of Water-Vac [JET-SPRAY] Trail-Cutting Operations at Lake Trafford.
Report by Regional Aquatic Botanist, Florida State Game and Fresh Water Fish
Commission, 29 June 1979.
Rozas, Lawrence P., and Zimmerman, Roger J. 1994. "Developing Design Parameters for
Constructing Ecologically Functional Marshes Using Dredged Material in Galveston Bay,
Texas." In Vol. 1 of Dredging '94, Proceedings of the Second International Conference on
Dredging and Dredged Material Placement Edited by E. Clark McNair, Jr. New York:
American Society of Civil Engineers.
Sands, Thomas A., and Young, Wayne. 1994. "Restoring and Protecting Marine Habitat." In
Vol. 1 of Dredging '94. Proceedings of the Second International Conference on Dredging
and Dredged Material Placement. Edited by E. Clark McNair, Jr. New York: American
Society of Civil Engineers.
State of Louisiana, Department of Natural Resources. 1993. "Routine Program Implementation
of the Louisiana Coastal Resources Program." Public Notice for General Permit 10 (CUP-
GP-10).
U.S. Environmental Protection Agency, Region 6. 1992. Wetlands Restoration By Sediment
Harvesting. Transportation and Placement. Report Prepared By Lee Wilson and
Associates, Santa Fe, New Mexico.
Wilber, Pace (U.S. Army Engineer Waterways Experiment Station), Luczkovich, Joseph, J., and
Knowles, David B. (East Carolina University). 1992. "The Long-Term Environmental
Effects of Thin-Layer Disposal on a Salt Marsh, Lake Landing Canal, NC." In
Proceedings. 13th Meeting of the Western Dredging Association. Mobile. AL
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Wilber, Pace (USACOE). 1992 Videotaped interview. In AZTEC DEVELOPMENT CO. 1992
and 1993. Project Video: JET-SPRAY® Aerial Placement of Dredged Material. Featuring
JET-SPRAY® Thin-Laver Placements on Saltwater Marsh and Freshwater Hardwood
Wetlands. [Projects include: Mississippi Delta (1992), City of Savannah (1993), and Hyde
County, NC (1982)]. Moxie Media, Inc., New Orleans, LA.
ADDITIONAL REFERENCES
Blair-Williams, Judith. "Weed Eating Machine Could Clean Waterways." Citrus County
Chronicle. 4 Aug. 1979, pp. 1,3.
Bowman, Ron, ed. "Mississippi Delta Rehab Project, Aerial Placement of Dredged Material."
World Dredging Mining & Construction [Special Focus: Environmental Benefits of
Dredging]. August 1992, US ISSN 1045-0343, Vol. 28, No. 8, p. 10.
Brown, S.D. Hyde County: Dredging of Bull Rock Area. Record Report for U.S. Department
of Army, Wilmington District Corps of Engineers, 19 March 1982.
Deal, Troy M. United States Patent #3.971.148-Dredge Cutter Head. United States Patent
Office, Washington, D.C., July 27, 1976.
Deal, Troy M. United States Patent #4T759.664-Method of Building or Restoring Marshes and
Beaches. United States Patent Office, Washington, D.C., July 26, 1988.
•Deal, Troy M. United States Patent #4.896.455—Method for Reducing Costs and Environmental
Impact of Dredging United States Patent Office, Washington, D.C., Jan. 30, 1990.
Deal, Troy M. United States Patent #5.167.469-Slurrv Distribution System Using Remote
Distributors. United States Patent Office, Washington, D.C., Dec. 1, 1992.
Deal, Troy M. United States Patent #5.211.511-[Method Patent] Slurry Distribution System
Using Remote Distributors United States Patent Office, Washington, D.C., May 18, 1993.
Doize, W. Cost/Efficiency Rating: Jet-Spray. Report of Production Engineer, Hawthorne Oil
and Gas Corporation, Lafayette, Louisiana, U.S.A., 15 Sept. 1982.
Faulk, R. Golden Meadow Jet-Spray Operation. Consultant Engineer Report for John E. Chance
& Associates, Inc., 1 Sept. 1982.
Gagliano, S., Meyer Arendt, K., and Wicker, K. "Landless in the Mississippi Delta Plain." In
Proc. 31st Annual Meeting, Gulf Coast Association of Geological Societies. Corpus Christi,
Texas, U.S.A., 21-23 Oct. 1981.
Gagliano, S., and van Beck, J.L. "An Approach to Multiuse Management in the Mississippi Delta
System." Houston Geological Society. 1975, pp. 225, 227, 228, 235, 236.
Gossett, D. and Moore, T. Lake Landing and Boundary Canal Dredging Project. Hyde CountyT
North Carolina. Report from North Carolina Department of Natural Resources
Environmental Specialist and Management Specialist to Field Services Section Chief, 15
July 1982, pp. 1, 2, 6, 7, 8, 12.
McClintock, W. Restoration of Lake Virginia. Report from City Engineer and Environmental
Consultant, City of Winter Park, Florida, 8 Sept. 1982.
Small, J.W. Lake Virginia Research Activities. Interim Report to Winter Park City Council from
• Rollins College Biology Department, July 1981.
Small, J.W. Development Effects of Recent Sediment Removal from Lake Virginia. Final Report
to City of Winter Park City Council from Rollins College Dept., Oct. 1982.
U.S. Environmental Protection Agency, Region 6. Nairn Wetland Nourishment/Creation
Demonstration. Candidate Project for the Priority Project List of the Coastal Wetlands
Planning, Protection & Restoration Act. Dallas, TX, 1992.
Wilber, Pace (Corps of Engineers Waterways Experiment Station), and Luczkovich, Joseph, and
Knowles, David (East Carolina University). "The Long-Term Environmental Effects of
Thin-Layer Disposal on a Salt Marsh, Lake Landing Canal, NC." World Dredging Mining
& Construction [Special Focus: Environmental Benefits of Dredging]. August 1992, Vol.
28, No. 8, p. 8. [Excerpted from "The Long-Term Environmental Effects of Thin-Layer
Disposal on a Salt Marsh, Lake Landing Canal, NC," by P Wilber, J. Luczkovich, and D.
Knowles].
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Wilber, Pace. "Case Studies of the Thin-Layer Disposal of Dredged Material-Gull Rock, North
Carolina." U.S. Army Corps of Engineers Waterways Experiment Station Bulletin.
Environmental Effects of Dredging. August 1992, Vol. D-92-3.
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AVOIDANCE REACTIONS OF FISHES IN OXYGEN, TEMPERATURE, AND
SALINITY GRADIENTS
D. Dorfinan, J. Berning, and B. Surgent
Monmouth University
West Long Branch, NJ 07764
Knowledge of fishes' ability to avoid potentially lethal levels of dissolved oxygen,
temperature, and salinity is necessary to predict the outcome of effluent discharges which may
alter these parameters.
For example, fish generally react to a deficient oxygen supply by breathing more rapidly,
and by increasing the amplitude of their respiratory movements. Another symptom of respiratory
stress is an increased tendency to swim. Jones (1964) states that fishes do not have an innate,
instinctive ability to recognize waters of abnormally low oxygen, that they will swim into it, or
remain in it should it flow over them.
With regard to temperature, Jones (1964) reports that fishes disappear from heated regions
of rivers, at least during warm months of the year. Dorfinan et at (1976) observed greater
concentrations of fishes in the discharge canal with higher temperatures, emanating from a nuclear
power plant. However, acclimation to artificially heated waters may make the fishes more liable
to cold death when the supply of warm water is interrupted.
Some freshwater fishes illustrate a tolerance for levels of 7-16 ppt salinity, as sodium
chloride. The level of tolerance varies with the species.
To examine the avoidance responses of several fish species to gradients of dissolved
oxygen, temperature, and salinity, two basic types of chambers (tubes) were designed and
constructed. One, a six-foot plastic see-through tube (Figure 1) allows a gradient. A gradient can
be provided in either direction by rearranging the reservoirs. Water is drained from five ports.
Dissolved oxygen is determined from samples obtained from vessels placed beneath the ports.
Temperatures are determined with probe thermometers inserted into openings evenly spaced
along the top of the tube. Salinities are also determined from these top openings by inserting a
plastic squeeze pipet and collecting water samples. In this type of tube, if a fish loses equilibrium
as a result of stress caused by altering one of the parameters, and does not reverse its direction it
may be fatal. The second chamber design allows test fishes two choices. The fish can either swim
forward and move out of the unfavorable stress, or it can reverse its direction and return to a safe
zone. This tube is square (Figure 2), and allows the fish to swim around the length of the
chamber and return to its point of origin. The chamber is 12 feet (3' X 3' X 3' X 3').
Determinations of dissolved oxygen (DO), temperature, and salinity are made with the same
methods described for the straight test chamber.
To examine avoidance reactions in oxygen gradients fishes (one, two, or three individuals)
were placed into either of the test chambers via larger openings at the top of the tube. Water with
D.O. at or near saturation flowed through one side of the tube, while water with reduced D.O.
flowed through the other side of the tube. To reduce the D.O., water flowed from a reservoir
through two marble-filled columns, where nitrogen gas (N2) replaced the D.O. D.O. levels as
low as 0.2 mg 02/Liter were provided. Fish movements were observed for 15-20 minutes, and
recorded on a work sheet (Figure 3), for later analysis.
Fishes observed included Fundulus heteroclitus (mummichog) and Cyprinodon variegatus
(sheepshead minnow). Some responses of these species are shown in Figures 4 and 5. In certain
tests the fish maintains its position, indicated by a straight or horizontal line. In other tests the
fishes are active, indicated by vertical, zig zag, lines.
Observations indicate that these species do not have the ability to detect low levels of
dissolved oxygen. The mummichog may be a poor test animal to examine for avoidance reactions
to low D.O., since this species was observed in D.O. levels of less than one mg/1 in field
conditions. Oxygen levels, determined several times during the test runs, may change from
reading to reading at the same port.
For studies of avoidance reactions of fishes in temperature gradients, mumichogs,
sheepshead minnows, Gambusia affinis (mosquito fish), Poecilia reticulata (guppy), and Ameiurus
100
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nebulosus (brown bullhead) were tested. Fish responses indicate that they cannot immediately
detect wide temperature differences and will swim into temperatures that may cause death
(Figure 6), unless they move out of these potentially lethal areas to more amenable temperatures
(Figure 7).
Only the mosquito fish was examined for its response to salinity gradients. The fishes,
acclimated in freshwater moved into areas of high salinity (Figure 8). This species normally may
be found in brackish waters.
Either chamber can provide a steep D.O., temperature, or salinity gradient. The fishes
tested should be those of smaller species, or juveniles of larger species. Preferably, they should
not exceed 40mm total length. This minimizes mixing of test waters. In addition, not more than
three fishes should be used simultaneously in any test run. It is difficult to observe more than
three fishes and it can also result in too much mixing of test waters.
LITERATURE CITED
Dorfinan, D., J. Kelly, Jr., and R. Hillman. 1976. Fishes In The Influent and Effluent
Waters Of A Power Plant. UNDERWATER NATURALIST, V.9, No.4, pp 12-13.
Jones, J.R.E. 1964. Fish And River Pollution. London, Butterworths 203 p.
101
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'CORKS-
INTAKE.
n n D
ii n n—IT
• ^^DRAINS
6 FOOT CHAMBER SIDE VIEW
INTAKE
© © ©
FIG. 1. 6 FOOT CHAMBER TOP VIEW
CORKSr"
RESERVOIR
9.© 0 ©«
*0
-0
O
1
\/
1
k 5"
1 /
_/i V
1
1
0"
©--
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— CORKS
0
RESERVOIR
FIG. 2. 12 FOOT CHAMBER TOP VIEW
•Mt: ^'__'_
1-3
FIG. 3. WORKSHEET (ST=STRAIGHT TUBE. SQ=SQUARE TUBE)
-------
PORT s
3.4
3.3
3.4
Graph line represents fisb movement in huge square tube
Numbers on Graph represent D.O. levels in mg/1
Range of D.O. Emm 1.2 - 4.O mg/1
3.6
2 3 4 S 6 7 I 9 10 11 12 13 14 IS 16
TIME IN MINUTES
FIG. 4. Avoidance reactions ofFundulus heteroclitus to
variations in dissolved oxygen.
PORT s
A5 3.S
3.5
Graph line represents flth movement in large square tube
Numbers on Graph represent D.O. levels in mg/1
Range of D.O. from 1.6 • 6.O mg/1
I 2 3 4 S 8 7 8 9 10 11 12 13 14 15 16
TIME IN MINUTES
FIG. 5. Avoidance reactions of Cyprinodon variegatusto
variations in dissolved oxygen.
Figures 4-5
103
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PORT s
7S 71 71
Graph line represents fish movement in square tube
Numbers on Graph represent Temperature (F)
Range of Temperature from 64 - 1O1 degrees F
Acclimation Temperature offish: 49 degrees F
Lost equilibrium
Terminated run
86
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
TIME IN MINUTES
FIG. 6. Avoidance reactions of Fondu/us heteroclitus to
variations in temperature.
6
PORT 3
Graph line represents fish movement in straight tube
Numbers on Graph represent Temperature (F)
Range of Temperature from 4O.S • 79 degrees F
Acclimation Temperature offish: 73 degrees F
51
SO
63 S6.5
79
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
TIME IN MINUTES
FIG. 7. Avoidance reactions ofPoec/7/a reticulatato
variations in temperature.
Figures 6-7
104
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PORT s
so ao ao to
Graph line represents fish movement in large square tut
Numbers on Graph represent salinity levels in
parts per thousand (ppt)
Range of salinity: O - 25 ppt
Acclimation salinity: O ppt
is is
1 2 3 4 S 6 7 8 9 10 11 12 13 14 15 16
TIME IN MINUTES
FIG. 8. Avoidance reactions ofGa/nbt/s/a aff/n/sto variations
in salinity.
105
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ENHANCING WATERBIRD HABITAT WITH DREDGED MATERIALS:
SOME SUGGESTIONS FOR IMPROVEMENT
Michael R. Erwin
U.S. National Biological Service
Patuxent Environmental Science Center
Laurel, Maryland 20708-4015
Using dredged materials from the maintenance of navigable waterways in the U.S. to
provide habitat for wildlife has been a long-standing policy ("beneficial use" program) of the U.S.
Army Corps of Engineers. The benefit to a number of waterbird and shorebird species has been
evaluated in a number of coastal and Great Lakes regions since the 1970s (see Soots and Landin
1978 for a summary). For example, in the middle Atlantic coastal region, 11 species of colonial
seabirds, (i.e., gulls, terns, skimmers, pelicans, 10 species of wading birds (i.e., herons, egrets,
ibises), 2 species of waterfowl, and 4 species of shorebirds use dredged material islands for
nesting and 37 other species use these habitats for feeding and/or roosting in the nonbreeding
season
Past Problems with Dredged Material islands
Recognition of several problems associated with dredged material deposition have been
acknowledged. The major ones include: (1) coverage of actual or potential shellfish or finfish
beds; (2) relocation or resuspension of toxic materials that had been buried in deep sediments in
harbors and channels; (3) the development of a relatively sterile monoculture of the aggressive
reed Phragmites australis. and; (4) changes in water circulation patterns in small embayments.
From a wildlife perspective, additional problems have been: (1) creating large containment sites
with extensive grassy areas. These sites may support large predatory gull populations and/or
mammalian predators; (2) failure to provide for diverse habitats including sources of freshwater;
(3) siting dredge islands near non-productive parts of the estuary, and; (4) using containment
dikes which reduce the attractiveness of the site to colonially nesting species (Soots & Landin
1978; Parnell & Shields 1990).
DESIGNING FOR WILDLIFE OBJECTIVES
To design dredged material islands more efficiently from a waterbird perspective, and to
minimize ecologically adverse effects on other species or communities, several design features
should be considered for inclusion.
1. Size — Islands ranging from about 2 to 10 hectares in area seem to be optimal for most species
of waterbirds that nest on dredged material islands (Erwin et al., 1993 & 1995). These are large
enough to include several habitat types but are small enough to preclude the permanent
establishment of most mammalian predators.
2. Location ~ Along the ocean coast, dredged material island(s) should be located fairly close to
an inlet on the inside of the terminal spits. They should not be located in or near the main tidal
channels for the inlet since erosion will be excessive. Bird use of dredge islands near inlets is
higher than on those remote from inlets presumably because of the proximity to rich feeding sites.
3. Configuration — Whenever possible, clusters of several islets should be considered. For
nesting birds, this arrangement provides alternatives after nesting failures due to flooding or
predation. Islets with different habitats and/or elevations provide refugia from storms, predators,
or competitors.
4. Shape — A horseshoe or kidney shape with the "back" facing the prevailing winds will allow
for a protected "harbor" area to develop and with it submerged aquatic vegetation (SAV). This,
in turn, will attract invertebrates and fishes which form the prey base for the waterbirds.
5. Topography — In general, irregular ridges among some sand/shell flats and small wet swales
will provide enough heterogeneity to attract most species of waterbirds. The elevation should be
low, with sloping sides and a maximum elevation of about 3 m above mean high water.
6. Vegetation — A mix of open sand/shell (for terns, Black Skimmers, Rynchops nigerT plovers,
American Oystercatchers, Haematopus palliatus). low ground cover (for willets, Catoptrophorus
106
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semipalmatus American Black Ducks, Anas rubripesT Gadwalls, A, strepera. or Eastern Brown
Pelicans, Pelecanus occidentalis). and woody shrubs such as Iva fhitescens or Myrica cerifera (for
nesting wading birds, cormorants, and pelicans) would provide an effective habitat mosaic for
nesting species. Large open mudflats and beach areas would attract large numbers of shorebirds
for feeding and roosting. Extensive sandy beaches will also attract nesting turtles. Ground cover
should include ivy and creeping vines, but not grasses. Grassy areas attract nesting Herring Gulls
(Larus argentatus^ and Great Black-backed Gulls (L marinus) which are predators on most other
waterbirds.
POPLAR ISLAND: A LARGE SCALE EXPERIMENT
A current project being planned by the Baltimore District of the U.S. Army Corps of
Engineers (COE) is Poplar Island, Talbot Co., on the eastern shore of Maryland. Here, an
approximate 1100 acre restoration is being planned. Because of the large size of the project, and
its "beneficial use" status, resource agencies including the the Maryland Departments of the
Environment and Natural Resources, Maryland Geological Survey, U.S. National Biological
Service, Fish and Wildlife Service, and National Marine Fisheries Service are providing input into
the design. As of August 1995, the design calls for a 50:50 wetland/upland ratio, and an 80:20
ratio of low marsh to high marsh in the wetlands (B. Walls, COE, and C. Donovan, Maryland
Envir. Service).
Because this containment facility has large capacity as a major objective and its siting fixed,
most of the six factors listed above are not relevant to the project. Nonetheless, we in the
resource agencies have been effective in helping steer the habitat development plan toward the
following:
1. Creating small isolated sand/shell islands of 1-2 ha in size in each of five large (200+ acre) cells
for nesting terns, skimmers, and shorebirds as well as terrapins. As these vegetate, they will be
colonized by American Black Ducks. These would be surrounded by a ditched perimeter in an
expanse of low Spartina marsh.
2. Planting the uplands with low woody shrubs to attract nesting wading birds and Black Ducks.
Minimizing grasses and using low vines (including poison ivy) instead to deter nesting gulls.
3. Including small freshwater ponds in the uplands as brood habitat for Black Ducks and as
drinking water for all other wildlife species.
4. Experimenting with different planting techniques for Spartina alterniflora and patens in the
wetlands to achieve mostly a low saltmarsh. In the low and high marsh, sculpting to achieve tidal
channels and pools may be necessary for use by shellfish and finfish. These features are essential
to maximize the diversity of wildlife and fisheries.
5. Creating intertidal flats for feeding waterbirds and encouraging SAV in subtidal areas of the
"harbor" area SAV should develop without planting if conditions are proper (e.g., sandy bottoms
with low turbidity should encourage Ruppia or Zostera growth, in turn, supporting shellfish and
finfish. SAV beds become important feeding sites for fish and turtles as well as wading birds and
waterfowl.
Since some of these techniques have not been rigorously tested in large areas before, the
project will be considered a large-scale "adaptive resource management" case (Walters & Hilborn,
1978) The results of several techniques used in the first cell will be evaluated before the
construction of subsequent cells. The entire project may take about 15 years for completion,
allowing a great deal of "adaptation" as each cell is developed and changes through time.
ACKNOWLEDGMENTS
I wish to thank Ralph Spagnolo and the Environmental Protection Agency for the opportunity to
present this information. I thank J. Burger, J. Gill, and J. Parnell for contributing ideas and
discussion on the topic.
107
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LITERATURE CITED
Erwin, R. M., G. M. Haramis, D. G. Krementz and S. L. Funderburk. 1993. Resource
protection for waterbirds in Chesapeake Bay. Environmental Management 17: 613-619.
Erwin, R. M., J. S. Hatfield and T. J. Wilmers. 1995. The value and vulnerability of small
estuarine islands for conserving metapopulations of breeding waterbirds. Biological
Conservation 71:187-191. .
Parnell, J. F. and M. Shields. 1990. Management of North Carolina's colonial waterbirds.
University of North Carolina Sea Grant Program. UNC-SG-90-03. Raleigh, North
Carolina.
Soots, R. F., Jr. and M. C. Landin. 1978. Development and management of avian habitat on
dredged material islands. U. S. Army Corps of Engineers, Tech. Report DS-78-18.
Vicksburg, Mississippi.
Walters, C. J. and R. Hilbbrn. 1978. Ecological optimization and adaptive management.
Annual Reviews of Ecology and Systematics 9: 157-188.
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TURNING THE TIDE ON TRASH:
ONGOING EFFORTS IN PUBLIC EDUCATION
Brigitte Farren
US Environmental Protection Agency, Region III
841 Chestnut Street
Philadelphia, PA 19107
INTRODUCTION
EPA is concerned about the amounts and types of debris in our oceans, coastal waters, and
on our beaches. This debris can have serious impacts on human health and marine life as well as
the aesthetic and its related economic damage it causes. EPA has identified articles of concern in
the marine environment which come from both land and sea-based sources. This poster session
illustrates the articles of concern that comprise this debris and its associated impacts to human and
marine life. The poster also describes ways in which the general public can help eliminate or
greatly reduce the amounts of this debris to our coastal waters and thereby alleviate its impacts to
our living resources.
Significance of the Problem
The presence in the marine environment of floating debris from anthropogenic sources has
received considerable public attention and concern. The debris enters the environment from a
number of land-based and ocean-based sources Land-based sources include inadequately treated
municipal sewage discharges, land-based recreational activities (e.g., beach use), and improper
solid waste disposal. Ocean-based sources include recreational and commercial boaters and
fishermen, cruiser lines, offshore mineral exploration, and operation of merchant and military
vessels.
The fate of man-made debris once it has been released into the aquatic environment varies
according to its form and material composition. Individual items may quickly sink to the bottom,
float at or near the water surface, or become suspended at a mid-depth. Those items that quickly
sink typically remain in the environment at'or near the release point. Items that float either at the
surface or at a mid-depth, however, may be transported by currents, winds, and other physical
processes to points far removed from the source. The presence of man-made debris has been
reported in oceans and coastal areas world wide, including areas remote from any identifiable
source.
Biological impacts of entanglement to marine mammals, sea turtles, birds, and fish have
often been obvious, as have the impacts of some debris ingested by these animals. However, the
impacts of ingestion may be quite subtle, such as the impacts of plastic resin-pellet ingestion to
seabirds. Entanglement in or ingestion of debris may result in drowning, inability to flee from or
defend against predators, starvation, suffocation, and permanent or life-threatening injury. It is
estimated that many thousands of seabirds and marine mammals die each year by ingesting or
becoming entangled in debris. Recent data show that approximately 30,000 northern fur seals die
annually due to entanglement, primarily in fragments of fishing nets (EPA, 1994).
The presence of debris may also impact local economies in several ways. First, damage
caused by entanglement or collision with lost gear can be costly to commercial fishermen in terms
of actual repair costs as well as the loss of valuable time during repair. Second, the presence of
debris on beaches may result in significant economic losses in areas dependent upon tourism. In
1987 and 1988 for example, beach closures due to washups of medical waste and other floatable
debris on New Jersey and New York beaches resulted in losses estimated to be as high as $1
billion over the two-year period (R.L. Associates, 1988). Third, the aesthetic quality of coastal
environments is degraded by the presence of man-made debris washed up onto shorelines or
carelessly discarded, regardless of whether or not an area is dependent upon tourism dollars.
A number of international agreements and Federal and State laws exist that address debris
releases into the marine environment from both ocean- and land-based sources. EPA and other
Federal agencies, including the National Oceanic and Atmospheric Administration (NOAA) and
the U.S. Coast Guard have responsibility for implementing and enforcing these laws. In addition,
a number of programs and initiatives have been introduced at the state and local level with
109
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support from citizens' groups and non-profit organizations. With all of these current efforts,
however, EPA believes that one of the most important is education. EPA believes it is essential to
develop comprehensive public awareness/education programs that will improve understanding of
debris impacts and encourage development of effective solutions. Also, unlike most other marine
pollution problems, the public can play a direct and significant role in reducing the marine debris
problem. Once people are educated about the sources and effects of marine debris, they will be
less likely to contribute to the problem.
LITERATURE CITED
EPA 1994. Status of Efforts to Control Aquatic Debris. EPA-842-K-94-002. U.S.
Environmental Protection Agency, Washington, DC. 30 pp. + appendices.
R.L. Associates 1988. The Economic Impact of Visitors to the New Jersey Shore the
Summer of 1988. Final Report prepared for the New Jersey division of Traveland
Tourism. R.L. Associates, Inc., Princeton, NJ 16 pp.
110
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THE SIMPLIFICATION AND INTEGRATION OF JURISDICTIONAL
CONSTRAINTS'
A CIS APPROACH TO ESTUARINE WATERSHED MANAGEMENT
Andrew M. Fischer
School of Marine Affairs
University of Washington
ABSTRACT
Throughout the US, complex sectorized jurisdiction^ frameworks constrain estuarine
watershed planning. The constraints produced by such complex interaction systems, prevent
coordinated management and planning. The Jurisdictional Restoration Planning (JRP) model of
the Liberty Bay Project addresses simplification and integration of Jurisdictional planning
frameworks so that area-wide coordinated management in the estuarine watershed's of Puget
Sound can be achieved. The JRP address simplification through a centralized information system.
The JRP addresses integration through a dynamic process of assigning values to Jurisdictional sets
of information. Once regional themes are simplified and established, then greater integration and
coordination among the jurisdictions can be formulated into more comprehensive management
strategies
WATERSHED MANAGEMENT AND JURISDICTIONAL CONSTRAINTS
Estuarine watershed planning in Puget Sound typically transcends existing political
boundaries involving a variety of agencies and groups. The blend of local, state, federal, and
tribal agencies as well as tribal and community programs form an elaborate system to manage an
estuarine watershed's natural resources The management strategies of these programs vary from
technocratic to collaborative approaches and include direct regulation from the federal level, state
agency directives, and local citizen planning initiatives (Table 1).
This framework involves a complex maze of regulatory, permitting and reviewing processes
often incomprehensible to the public and local planners. These complexities produce an
overloaded system in which individual interests are often unable to visualize and comprehend their
role in a planning process. Conflicts occur between competing interests, among different levels
of government, between different agencies and jurisdictions, and between various industries and
interest groups. The examples provided below show that the management tools for estuarine
watershed planning in Puget Sound are compromised by regulatory inadequacies and legal issues
and are plagued by goal conflicts (Table 2).
Regulatory Inadequacies
In Washington state, a number of studies (Kunz et al., 1988; Cooper 1986; Eliot 1985)
have demonstrated that, at least up until mid-1986, inadequate wetland mitigation planning,
follow-up, documentation, monitoring, and enforcement were all contributing to the
ineffectiveness of mitigation within the §404 permitting process. Also, studies evaluating the
effectiveness of the §404 program of the Clean Water Act indicate that program goals are not
being met (Rylko & Storm, 1991; Weinman & Kunz, 1994.; Blumm & Zaleha, 1989). And,
despite the past decade of progress in dealing with wetlands protection, improvement of the
wetlands delineation manuals, memoranda of agreement between the Corps of Engineers and
Environmental Protection Agency to guide the consideration of mitigation in the §404 permit
process, significant loss and degradation of wetlands still continue. The main reason for wetland
loss and degradation is that "many activities that affect wetlands are beyond the reach of the Clean
Water Act" (Weinman & Kunz, 1994).1 In general, lack of regulatory inadequacies can leave
The limitations include: (1) only some activities are regulated; (2) only some wetlands are regulated; (3) case-by-cue permit programs
do not provide for landscape or watershed considerations in designing compensatory mitigation; (4) attitudes of those undertaking creation and
restoration is created by legal requirement rather than a desire to increase wetland resources or provide long-term management objectives.
Ill
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weaknesses in wetland policies and regulations and lead to a failure of addressing system-wide
concerns.
Legal Issues
Property exemptions and constitutional rights issues present constraints to the adoption of a
system-wide perspective in estuarine watershed planning. The single family residence exemption
under the Shoreline Management Act (SMA) reflects a populist notion of fewer constraints on
individuals. The single-family residential development exemptions have resulted in a substantially
altered natural environment and development activities along the shoreline which frequently
conflict with the Public Trust Doctrine and the goals of the Shoreline Master Program (SMP)
(Lambert, 1993).2
Constitutional rights as expressed through Supreme Court decisions have broadened
property rights in recent years by determining that land use requirements on private property can
constitute a "takings." In Dolan v. Tigard (114 S. Ct. 2309, 1994) the Supreme Court ruled that
requesting public land use of private property was unconstitutional and, in setting a new standard,
the Supreme Court said that cities must show that the land request "is related both in nature and
extent to the impact of the proposed development." In another case, Lucas v. South Carolina
(112 S. Ct. 2886, 1992), the state setbacks requirements for construction on barrier islands was
also found to be a takings of the full beneficial use of the private property. By elevating property
rights, the court has given the judiciary greater freedom to interfere with state and local
regulations that control land development in environmentally sensitive areas. Municipalities and
states which increasingly have been seeking land concessions as ways to solve environmental and
recreational needs may find it increasingly difficult to plan for estuarine watershed protection and
restoration given these rulings.
Goal Conflicts
Mismanagement of estuarine watershed resources and ineffective planning has been evident
in the watersheds of Puget Sound. Continued growth and development in the watersheds has
placed additional stress on fisheries resources. Some attempts to restore degraded fish runs by
the Muckleshoot Indian Tribe have been met with failure (Stevens, 1993). Disagreements
between the various watershed users (primarily, fishing and recreation vs. development interest)
make restoration a very time-consuming and heated process (MIT, 1993). For example, housing
developments may not be coordinated with tribal salmonid watershed restoration efforts and may
result in the destruction of stream characteristics, leading to increased storm water runoff,
erosion, and flooding (MIT, 1993). The housing needs of one local community cannot always be
dealt with through strictly local solutions because one community's quick, inexpensive, and
inadequate solutions seem to impose burdens on other community or watershed interests (Baxter,
1974).
Above, some constraints within the current estuarine watershed planning framework have
been illustrated. The cause of these constraints are several. First, limited laws are applied to new
problems year-by-year resulting in an overloaded regulatory process with a plethora of legislation
aimed at providing quick solutions to specific problems. These quick solutions inadequately
address the consequences and impacts of interrelated environmental, social, and economic issues.
Second, watershed planning is conducted through a technocratic approach with scientists and
engineers in charge. This approach often provides simple myopic solutions to complex, integrated
problems. Third, in a tight legal and budget structure agencies have little flexibility and are under
pressure from the legislature and the judiciary allowing them little room to implement innovative
system-wide approaches.
In Puget Sound simplification and integration of the estuarine watershed planning
framework must first be realized so that a system-wide planning perspectives can follow.
Simplification refers to simplified administrative procedures, simplified data management and
planning techniques adapted to regional manpower and issues and localized decision-making.
This illustrates that numerous individual decisions on shoreline development can have an aggregate effect on the resource that is the same
as if one major decision had been made to destroy the rresource (Rieser, 1991).
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Such a system requires simplification so that planning options are clear, accessible, and
comprehendible. "Policy is integrated to the extent that it recognizes its consequences as decision
premises, aggregates them into an overall evaluation, and penetrates all policy levels and all
government agencies involved in its execution" (Underdal, 1980). Such a system requires
integration to provide for more effective collaboration in planning for the management of
watershed resources
THE JURISDICTIONAL RESTORATION PLANNING MODEL:
STEPS TOWARD SIMPLIFICATION AND INTEGRATION
The Jurisdictional Restoration Planning (JRP) model (Fischer, 1994) is a geographically
reference information system that begins to simplify and integrate jurisdictional constraints in
watershed management. The JRP model is a component of the Liberty Bay Restoration Planning
Model (RPM)(WSG, 1992) and the Liberty Bay Project.
The JRP model consists of maps, a database and an evaluative matrix. The maps display
sets of jurisdictional information (boundaries) throughout the Liberty Bay watershed in Kitsap
county, as well as the boundaries of overlapping jurisdictions. These sets of information are also
referred to as Jurisdictional Landscape Units (JLU). This map is geographically linked to a
database which provides a detailed description of the JLUs, such as a description of each
jurisdiction's legal foundation, relevant statutes and planning procedures. This map and data base
provide a centralized and simplified display of information. The map is also linked to a matrix in
which relative values are assigned to sets of criteria to estimate a level of jurisdictional feasibility
of within JLUs. This is where integration is achieved.
Simplification
Simplification in watershed management can be achieved through the JRP model by
providing a medium of centralized information sharing. Centralized information about
jurisdictions in one information system can more easily alert users to the problems associated with
regulatory inadequacies, as well as identify goal conflicts and the other constraints. Organization
of information at the regional level presents greater opportunity for jurisdictions with
responsibilities in various sectors affecting the region to realize and examine problems. In such a
situation, jurisdictional myopia can be circumvented and cooperative approaches to natural
resource planning can begin to be understood. These improvements may reveal new management
strategies and suggest new institutional arrangements.
Integration
Integration in watershed planning can only be realized if regulatory and management
policies across multiple sectors are aligned to represent regional or system-wide interests. The
JRP model addresses these issues of integration through a dynamic thematic planning process of
assigning values to jurisdictional sets of information or JLUs within the watershed, and overlaying
these values with other sets of values (Fischer, 1994).
In the JRP model, criteria of JLUs are rated based on an evaluative process to determine
certain thematic management trends. The JLUs can then be ranked and prioritized and displayed
on a map. Developing common values or thematic trends across multiple and diverse jurisdictions
allows individual actors to consider their role in the watershed and move toward an integrated
management process.
Similarly, other component maps can be overlaid with prioritized JLUs to determine
accumulations or combinations of certain thematic patterns throughout the watershed. Such an
analysis can be conducted for multiple components or levels of information as the need for
comprehensiveness in estuarine watershed planning varies. This provides the ability for planners
and managers to monitor the impacts of system-wide decisions as they occur across components
of information, assess coordination possibilities and aggregate them into more comprehensive
management typologies.
As we begin to understand how to identify jurisdictional constraints through an information
system, and to resolve them by integrating various components of information, we can begin to
understand how the pluralistic nature of jurisdictions can accommodate a system-wide perspective
in the management of estuarine watersheds Federal, state, local, and tribal agencies and
113
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programs will be able to coordinate the elaborate jurisdiction^ framework and reduce conflicts
and inadequacies arising from a fragmented and overloaded system. Accordingly, more
coordinated and effective management typologies adapted to regional needs and capabilities will
result.
ACKNOWLEDGEMENTS
The author wishes to thank Marc Hershman, Annette Olson, Boykin Witherspoon, and Sally'
Schauman for their input and assistance in preparation of this manuscript.
REFERENCES
Baxter, L.D. 1974. Regional Politics and the Challenge of Environmental Planning.
Environmental Quality Series, no. 22. Davis, CA: Institute of Governmental Affairs,
University of California.
Blumm, M.C. and D.B. Zaleha, 1989. Federal wetlands protection under the Clean Water
Act: regulatory ambivalence, intergovernmental tension and a call for reform.
University of Colorado Law Review Fall:695-772.
Cooper, J.W. 1986. An overview of Estuarine Habitat Mitigation Projects in Washington
State. Prepared for USFWS. 18p.
Eliot, W. 1985. Implementing mitigation policies in San Francisco Bay: a Critique. Prepared for
the California State Coastal Conservancy.
Fischer, A. 1994. Jurisdictional constraints and system-wide perspectives: Simplification and
integration in restoration planning. Master's Thesis, School of Marine Affairs,
University of Washington.
Kunz, K., M. Rylko, and E. Somers. 1988. An assessment of wetland mitigation practices in
Washington State. In Proceedings from the first annual meeting on Puget Sound
research, 789. Olympia, WA: Puget Sound Water Quality.
Lambert, P. 1993. Evaluating the effectiveness of the state Shoreline Management Act of
1971 in protecting Public Trust Doctrine rights. Master's Thesis, School of Marine
Affairs, University of Washington.
Muckleshoot Indian Tribe (MIT). 1993. Comprehensive Threat and Needs Assessment:
Muckleshoot Indian Tribe Usual and Accustomed Fishing Area. By Andrew M.
Fischer. Auburn WA.
Rieser A. 1991. Ecological preservation as a public property right: An emerging doctrine in
search of a theory. Harvard Environmental Law Review 15:393-433.
Rylko, M. and L. Storm, 1991. How much wetland mitigation are we requiring? Or, is no net
loss a reality? Volume 2 of Proceedings: Second Annual Meeting on Puget Sound
Research, 314-327. Olympia, WA: Puget Sound Water Quality Authority.
Stevens, C. 1993. Personal Communication. Muckleshoot Indian Tribe, Auburn,
"Washington.
Underdal, A. 1980. Integrated marine policy: What? why? how? Marine Policy July: 159-
169.
Washington Sea Grant Program (WSG). 1992. Strategies for the restoration of coastal aquatic
environments. Proposal submitted to the Washington Sea Grant Program, University of
Washington, Seattle, WA.
Weinman, F. and K. Kunz. 1994. Wetlands: Infusion of Restoration into the Management
Formula. In proceedings of a workshop Partnerships and opportunities in Wetland
Restoration, March 1991, USEPA Region 10, EPA 910/R-94-003.
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ACRONYMS
CWA - Clean Water Act
RHA - Rivers and Harbors Act
SMA - Shoreline Management Act (Washington State)
HW - High Water
PSWQA - Puget Sounds Water Quality Authority
DOE - Department of Ecology (Washington State)
NPDES - National Pollutant Discharge Elimination System
DCD - Department of Community Development (County Level)
CSOs - Combined Sewer Overflow
BMP - Best Management Practice
SWM - Surface Water Management (County Level)
CZMRA - Coastal Zone Management Reauthorization Act
CZMA - Coastal Zdne Management Act
WAC - Washington Administrative Code
GMA - Growth Management Act (Cities and Counties)
RCW Revised Code of Washington
SEP A - State Environmental Policy Act (Washington State)
HPA - Hydraulics Permit Act (Washington State)
EPA - Environmental Protection Agency
NOAA - National Oceanic and Atmospheric Administration
USCG - United States Coast Guard
CORP - Army Corp of Engineers
USFW - United States Fish and Wildlife Service
DNR Department of Natural Resources (Washington State)
RCRA - Resource Conservation and Recovery Act
DOT - Department of Transportation (Washington State)
CERCLA - Comprehensive Environmental Response Compensation and Liability Act
FEMA - Federal Emergency Management Agency
OPA - Oil Pollution Act
NCP - National Contingency Plan
NEPA - National Environmental Policy Act
ESA - Endangered Species Act
WDFW - Washington Department of Fish and Wildlife
SMP - Shoreline Management Plans (Washington State)
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TABLE 1: WATERSHED PLANNING FRAMEWORK
Plans
Nonpotnt Pollution
Watershed1 Action Plan*
Stormwater
Bonn Plan*
Storm Water Mgt
Development Retulation
Land Vie
Growth Management
Shoreline Management
SMP
Geographic
Scope
biogeognphic
area: watershed
diitinclive
geographic areas
within the
comprehensive
plan having a
unified interest
political districts:
urban citiei,
counties,
municipalities
urban, citiei,
subdistricU
political districts:
fastest growing
counties and cities
(stops at HW
mark)
federal, tribal,
county/city
shorelines to 200'
Agency
.
PSWQA and
DOE; citizen
involvement
DOE, citiei, and
counties
PSWQA and
DOE (administer
programs and
NPDES permits)
DCD, counties,
citiei
local jurisdiction
DOE, county and
city planning
commissions,
shoreline
hearings board
Problems to
Address
non-point pollution:
stoimwater and CSOi,
agriculture practices,
on-site sewage, boats
and marinas
flood zones, aquifer
recharge, fish and
wildlife habitat,
wetlands
shellfish beds, fish
habitat, sediment
contamination, water
and sediment quality
private land
development, roads,
other public services
conservation of
resources and
protection of critical
areas
shoreland
development, riparian
and floodplain mgt.,
fish and wildlife
habitat protection,
public access and
recreation
Focus
source control
protection
technocratic;
engineering
approach
Control of quantity
and quality of
water
development
goals, zoning
growth planning
"protection* of
shoreland through
management of
uses.
Actions to
Consider
plan including:
BMP's,
ordinances,
permits,
education
stormwater facilities,
habitat enhancement,
sensitive area
protection,
regulations, source
control
SWM programs;
NPDES permits for
watershed;
ordinance! for
erosion control;
education; technical
assistance; draft
legislation (HPA)
zoning ordinances,
building and
development permits
impact fees,
sanctions, incentives.
grants excise tax
environmental
designations (natural,
conservancy, rural,
semi-rural, urban);
substantial
development permits;
performance
standards
Legal Foundation
Federal
CWA J319
CWA J319;
NPDES;
CZMRA } 6217
(Nonpoint
pollution control
program)
•
Public Trust,
CZMA
State
WAC
400-12;
cigarette tax
funding
GMA;
RCW
36.70.330
36.70.340
36.70.350
PSWQA plan,
RCW 90.48
(state water
quality
standards)
state statutes
GMA: ESHB
2929
SMA (1971),
SEPA
Local
plan using
ordinances,
agreements
stormwater
utility funds;
agency task
force
stormwater
management
plan, permits
planning and
zoning
ordinances
local
comprehensive
plans
Jurisdictional
Shoreline
Management
Master
Program
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TABLE 1: WATERSHED PLANNING FRAMEWORK (continued)
Plans
Flood Plain Management
Hazardou* Subataneca
Sediment Remediation
Habitat Retention
404 Mitigation
NRDA
Endangered Specie* Ad
Tribal R«ourcea
Protection
Geographic
Scope
aquatic flood
plaint
Superfiind litei,
RCRA- hazmat
from current
ioduitrial
operationi
404-developmeot
tile ipecific
mitigation project*
NRDA (ettlementi
endangered species
habitat
Uiualand
Accuitomed
Fiihing Ground
Agency
Federal
Emergency
Management
Agency
EPA, DOE,
NOAA, USCG
EPA (CWA
|404), CORP
(RHA |10),
DOE (SMP),
DOT
NOAA
USFW, WDFW,
DNR
Tribe and Tribal
Council (the
tribe'i deciiion-
making body)
Problems to
Address
natural disasters and
property damage due
to flooding
contaminated
sediments, liability
aueti and coune of
remedial action,
treatment and storage
permiti (RCRA)
wetland! Ion (10/404),
habitat protection
(local SMP)
damage aueument and
rettoration (NRDA)
recovery and nirvival
of endangered and
threatened species
fiihing acceii,
habitat lou and water
quality degradation •
Focus
iave liver, protect
property, public
health, and lafety
liability for
damage
(CERCLA),
current waite
(RCRA)
avoid, minimize,
compensate
wetland
development for
no-net lou;
natural resource
trait
•peciei nirvival in
conflict with
development
project! or other
forms of economic
activity
preserve and
develop habitat
and protect treaty
rights
Actions to
Consider
mitigation, analysis
and Revaluation of
practical alternatives,
building codes and
development setbacks
capping, dredging,
disposal, treatment
(CERCLA);
permitting waste
(RCRA)
enhancement,
creation, mitigation
of habitat
damage assessment
and restoration
aquatic land
acquisition, native
species transplants
enhance quality and
quantity of salmon
and shellfish
resources and their
habitat
Legal Foundation
Federal
FEMA
RCRA,
CERCLA,
NRDA, OPA,
NCP
CWA (404,
RHA |10,
CZMA, NEPA
natural resource
damage
regulations
ESA (Habitat
Recovery Plans)
federal treaties
(e.g. Point Elliott
and Medicine
Creek)
State
Floodplain
Management
Program,
RCW 86.24
Model Toxic
Control Act
(MTCA)
SMP
designation of
critical and
sensitive areas,
SEPA (protect)
identified state
trustees
Priority
Habitat and
Species
Program
(DNR*
WDFW)
US v.
Washington
(384 F Supp.
212) 'The
Bold!
Decision"-
Local
County
Community
Development
Departments
local SMPs,
volunteer
DOE/ King
County
Wetlands
Protection
Program
identified
municipal and
local trustees
-------
TABLE 2: ILLUSTRATIVE JURISDICTIONAL CONSTRAINTS
Problem type
Regulatory Inadequacies
Legal Issues
Regulatory Programs
Constitutional Rights
Goal Conflicts
Example Constraint
§404 wetland mitigation
Shoreline Management
Master Program
Dolan v. Tigard
Lucas v. South Carolina
Tribal Fisheries and
Growth Management Act
Legislation
§404 CWA, §10
RHA
SMA
Takings Clause of
the 5th
Amendment
US v Washington
(384 F Supp. 212)
and ESHB 2929
Problem
Description
Inadequate
monitoring and
geographic scope
Property rights
exemption diminish
public trust goal
Interferes with state
and local efforts to
plan for community-
wide interests
Conflicting interests
interfere with project
goals
118
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SENTINEL SPECIES: TRACE METAL ECOTOXICOLOGY IN THE OYSTER
TOADFISH (Opsanus tau)
John W. Foerster1
Scott D. Smart1
F David Correll2
Douglas W. Edsall2
Departments of Oceanography(l), and Physics(2)
U.S. Naval Academy
Annapolis, MD. USA 21402
ABSTRACT
Oyster toadfish (Opsanus tau) are a resident, non-migratory part of the estuarine benthic
food web along the U.S. eastern coast. They are a sentinel species with the potential to extract
toxic environmental trace metals, to test this hypothesis, we are studying toadfish resident in the
Chesapeake Bay near Annapolis, Maryland. This area is away from any direct industrial or
commercial effluents carrying trace metals but has concentrations of trace metals in the benthic
sediments. Using a proton induced x-ray emissions (PIXE) system, this study concentrates on
trace metals found in the liver. The PIXE system allows us a rapid method to determine trace
metal types, concentrations and an archiving method for samples Present analyses of various
size toadfish show that the livers contained concentrations of chromium (5.9-51.7 mg/L), copper
(3.3-26.0 mg/L), and zinc (8.6-29.9 mg/L). The trace metal amounts vary as a function of the
size, age, and sex of the fish. Copper and chromium concentrations deplete with age after the
reproductive phase while zinc concentrations increase. Generally, the trace metals have an
accumulation pattern of chromium>zinc>copper. Thus, the life history of the animal appears as
an important factor in trace metal accumulation, and leads us to accept the hypothesis..
INTRODUCTION
Estuarine and marine environments are the repositories of anthroprogenic wastes (Kennish
1992). Of the five main categories of wastes entering the coastal ocean system, the trace metals
are significant because they are:
• persistent,
• toxic at high concentrations, and
• cumulative in the tissues of biota (Kennish 1992).
Trace metals are bioactive in small concentrations (aiding in biochemical activities) but toxic in
higher concentrations This study tests the hypothesis that the oyster toadfish (Opsanus tau), as
part of the estuarine benthic food web, extracts potentially toxic environmental trace metals. As
such, the toadfish becomes a sentinel, a potential marker, for the effects of trace metals.
Oyster toadfish live on the bottom of estuaries in the sediments (Lippson & Lippson, 1984;
Gudger, 1910). Their overall range is from the New England Atlantic coast of the United States
to Florida (Gudger, 1910). Toadfish do not migrate but complete their life cycle in the area of
spawning (Grudger, 1910). They are a resident species and omnivorous feeders (Grudger, 1910).
In the Annapolis area, toadfish feed mainly on small shellfish and fish.
The area under study near Annapolis is in the northern portion of the Chesapeake Bay
estuary. Scientifically, the Chesapeake Bay is a sink for trace metals from mining, boating,
manufacturing and heavy industry (Sinex & Wright 1988). When trace metals are in minimal parts
per billion (ppb) concentrations, they are important in the health of aquatic animals (Table 1). As
the environmental amounts increase, biological uptake concentrates them. These trace metals may
now exert multiple effects depending on the concentration of the metal and its chemical species.
Figure 1 lists a variety of these effects relative to the oyster toadfish. As with any environmental
variable, the trace metals act within the scope of Shelford's Law of Tolerance (1913). There is an
optimal range at which the organism benefits.
This study concentrates on the accumulation of chromium, zinc and copper in the oyster
toadfish.
119
-------
For this initial study, we concentrated on the liver because of the important vital functions
performed to
• produce bile,
• regulate blood sugar,
• deaminate amino acids,
• make blood proteins,
• make clotting substance, and
• excrete breakdown products of bile and haemoglobin.
If this organ failed, the animal failed. Our results suggest cites of interference in the health and
vigor of the life cycle of this benthic fish.
MATERIALS AND METHODS
Study fish of various sizes (15.3 cm to 35.2 cm) and age classes (II to XII) provided us
with a spectrum offish from adolescence to old age. We measured each fish for total length and
determined the age according to the method of Schwartz and Dutcher (1963). From each fish, we
remove the liver and prepare it for analysis using a proton induced x-ray emissions (PIXE) system
(Foerster et al., 1994). In addition to the fish livers, we took sediment grab and core samples of
the study area bottom for analysis with the PIXE.
Once we measured the concentration and presence of the elements in each liver sample, we
used statistical procedures to develop probable cause and effect relationships. One method was
normalization according to the equation (N=A/L) where N is the normalization statistic, A is the
animal's age and L is its total length. Toadfish weights vary widely and the standard
determination of length to weight ratios are not reliable measures. This statistic allows a closer
grouping of individuals. Where applicable, such as plotting and analyzing the uptake and release
of the trace metals, we used multiple regression fitting curves with a 5th order polynomial.
Our focus was on establishing a reproducible and rapid analysis procedure and identifying
trends in the fish and the environment.
RESULTS AND DISCUSSION
Environmental Analysis
The immediate area from which we harvested the toadfish, had sediment concentrations of
(Zn>Cr>Cu, 114.18 ppm>66.78 ppm>35.56 ppm).
Figure 2 reflects the relative and comparative concentrations of the three trace metals
studied compared to the environment. Toadfish livers have more chromium concentrated,
followed by zinc and then copper.
Biological Analysis
Figure 3 lists the biological influences on trace metal accumulation or reduction. This study
concentrates on the gray areas in Figure 3. What we find is the oyster toadfish liyers are enriched
far above the water concentrations and below the sediment (Figure 2).
Comparing our fish measurement data to the State of Maryland information (Schwartz &
Dutcher, 1963), we accepted our data as reflecting a normal toadfish population in the Maryland
waters of the Chesapeake Bay. We studied various year classes and divided the animals according
to sex. Oyster toadfish males tend to be larger (in length) than the females depending on age
(4-5%).
Figure 4 shows trace metals concentrations in the livers as greatest in females. Females
probably do not live beyond the 7th year class and males beyond the 12th (Grudger, 1910;
Schwartz & Dutcher, 1963). Over their life cycle, oyster toadfish females in the Annapolis area
appear to concentrate the three trace metals more than the males. The females accumulates 31%
more chromium, 17% more zinc, and 15% more copper. During the reproduction years the
females store, 38% more chromium, 21% more zinc, and 38% more copper.
Figure 5 has curves for each of the trace metals studied. In curves (A) and (B) the trend is
to accumulate chromium and copper during the early log phase of growth. At adolescence the
120
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animals tend to eliminate some of the trace metal and re-accumulate during the reproductive
phase finally releasing chromium and copper as they go into old age. Zinc (C) appears to
generally accumulate throughout the life cycle with a build-up in the reproductive phase, and
some loss occurs as old age progresses. The accumulation of zinc continues in the males until
they reach the limit of their life cycle.
With this initial information, we hypothesize that the trace metals enter the oyster toadfish
life cycle as illustrated in Figure 6. Accumulation of chromium and copper occurs during the
geometric growth phase and during prime reproduction time. Zinc tends to enter the life cycle in
greater concentrations after the geometric growth phase. The body stores these trace metals, but
the mechanism, and the overall impact of this storage on future generations is for further study.
We do not know if trace metals transfer to the gonads of the toadfish thus reducing the viability of
the spawn and/or move into the developing embryos.
CONCLUSION
Environmental managers charged with remedial efforts to restore and clean a contaminated
habitat often have no information on the level of trace metal contamination and its effect
(Campbell & Tessier, 1991). The oyster toadfish may help because it is a sentinel species. Future
ecotoxicological work must focus on the sub-lethal impact to the life cycle of organisms. Oyster
toadfish point the way and offer a biological model for assessing the effects of trace metals. From
this initial study, we conclude that
• oyster toadfish accumulate trace metals,
• the pattern of concentration of the trace metals in the Chesapeake Bay is
(Cr>Zn>Cu),
• oyster toadfish accumulate trace metals in a variable pattern depending on age and
sex,
• females concentrate 31% more Cr, 17% more Zn, and 15% more Cu than the males,
• copper and chromium reduce with age in both sexes,
• males lose more chromium and copper than females,
• both genders accumulate zinc and loose very little over their life cycle, and
• when assessing survival of the species, any environmental analysis of influences on a
population must take into account the gender, state of the reproductive tissue, the
animals survival, and the transference of trace metals to future offspring.
As a sentinel species, the oyster toadfish give us an opportunity to follow the influence of trace
metals on a population.
ACKNOWLEDGMENT
Information in this paper extracted from Foerster etal., 1994.
121
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REFERENCES
Campbell, P.G.C., and A. Tessier. 1991. Biological Availability of Metals in Sediments:
Analytical Approaches. J.-P. Vernet (ed.). In Heavy Metals in the Environment,
Elsevier, New York, pp. 161-173.
Foerster*, J., S. Smart, F. D. Correll, and D. W. Edsall. 1994. Sentinel Species: Biologically
Active Trace Metals in the Livers of the Oyster Toadfish (Opsanus tau). Vol. 5, pp.
1994-2008. In: P.Wells and P. Ricketts (ed.). Proceedings Coastal Zone Canada '94.
Halifax, N.S.
Grudger, E.W. 1910. Habits and Life History of the Toadfish (Opsanus tau ). Bull. U.S. Bur.
Fish. 28:1073-1099.
Kennish, M.J. 1992. Ecology of Estuaries: Anthropogenic Effects. CRC Press, Inc., Boca
Raton.
Lippson, A.I, and R.L. Lippson. 1984. Life in the Chesapeake Bay. The Johns Hopkins
University Press. Baltimore.
Schwartz, F.J., and B. W. Dutcher. 1963. Age, Growth, and Food of the Oyster Toadfish
Near Solomons, Maryland. Trans.Am. Fish. Soc. 92:170-173.
Shelford, V.E. 1913. Animal Communities in Temperate America. Univ. Chicago Press.
Chicago.
Sinex, S.A., and D. A. Wright. 1988. Distribution of Trace Metals in the Sediments and Biota
of Chesapeake Bay. Mar. Poll. Bull. 19:425-431.
* Reprint available from J. Foerster, Oceanography (9d), U.S. Naval Academy, Annapolis, MD
21402
122
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TABLE 1.
Importance of the trace metals studied to the biological systems
of the oyster toadfish.
TRACE METAL
BENEFIT
chromium (Cr)
Insulin Production
(promotes maximum uptake of glucose by
tissue)
zinc (Zn)
Regulate Functions Inside of Cells
a. turgor
b. osmotic balance
c. enzyme production (carbonic
anhydrase, peptidase)
copper (Cu)
Regulate Functions Inside of Cells
a. respiration
b. haemoglobin formation
c. enzyme production (cytochrome
oxidase)
123
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ANTAGONISM \
ADDITION |
SYNERGISM |
MORTALITY
mmm^^m « • * «••• • •
Cr-LC 5j= 0.08-480.0 ppm
Zn-LC = 0.84-40.90 ppm
0.060-2.40 ppm
BLOOD
CHEMISTRY
Cr, Zn, Cu
GROWTH
RETARDATION
Cr(?), Zn, Cu
RESPIRATION
Cr, Zn, Cu
TISSUE/ORGAN CHANGES
Cr, Zn, Cu
ENZYME DE-ACTIVATION
Cr, Zn, Cu
REPRODUCTION
Cr-UNKNOWN
Zn-INHIBIT SPA WNING
Cu-BLOCK SPA WNING,
REDUCE FECUNDITY
CREATE ABNORMAL FRY
REDUCE YOUNG SURVIVAL
Figure 1. Projects potential effects on the oyster toadfish (Opsanus tau) from the three trace metals under study.
-------
SEDIMENT
LIVER
WATER
ZINC
CHROMIUM
TRACE METAL
COPPER
Figure 2. Concentrations of the three trace metals in the environment compared to the liver.
-------
LIFE HISTORY STAGE
PROTECTION
ENVIRONMENTAL FACTORS
to
TRACE METAL TOLERANCE
ACTIVITY
STARVATION
Figure 3. The fishes' condition can affect the accumulation and reduction of the trace metals. The gray areas are the conditions
addressed in this study.
-------
M = Male
F = Female
A=AII
CHROMIUM ZINC COPPER
TRACE METAL
-------
a
a
O
ac
x
u
50
40 H
30
20-
10-
SEXUAL MATURITY
0.1 0.2 0.3
RATIO (AGE/LENGTH)
Is)
00
0.4
c 60
50-
^ 40-
a
* 301
U
N 20-
10
E
a
a
DC
111
a.
a.
O
O
SEXUAL MATURITY
SEXUAL MATURITY
0.2 0.3 0.4
RATIO (AGE/LENGTH)
0.1 0.2 0.3
RATIO (AGE/LENGTH)
0.4
Figure 5. Accumulation and reduction patterns for each of the trace metals during the life span of the oyster toadfish. Note the
increased accumulation during reproduction tune. The normalization statistic (age/total length) is the ordinate. A=chromiunr
B=copper; C=zinc.
-------
K)
Cr, Cu +
Cr-, Cu-,Zn
REPRODUCTION
LINEAR GROWTH
ETAL TRANSFER AND TOLERANCE ?
HATCH
EMBRYO
SPAWN
OLD AGE
Figure 6. Life cycle of the oyster toadfish (Opsanus tau) identifying where the three trace metals appear to enter (+) and leave
(-) (the hatch was redrawn from Lippson and Lippson 1984).
-------
DDT CONTAMINATION IN COMMERCIALLY AND RECREATIONALLY
IMPORTANT FTNFISH AND SHELLFISH SPECIES FROM ESTUARINE AND
COASTAL MARINE WATERS OF NEW JERSEY
Michael J. Kennish
Institute of Marine and Coastal Sciences
Rutgers University
New Brunswick, New Jersey 08903
Bruce E. Ruppel
Division of Science and Research
New Jersey Department of Environmental Protection
Trenton, New Jersey 08625
ABSTRACT
Gas chromatographic analysis of more than 150 tissue samples from three finfish species
(bluefish, Pomatomus saltatrix, striped bass, Morone saxatilis, weakfish, Cynoscion regalis) and
one shellfish species (blue crab, Callinectes sapidus) collected in estuarine and coastal marine
waters of New Jersey between 1988 and 1991 reveals variable levels of DDT [ 1,1,1-trichlor'o-2,2-
bis (p-chlorophenyl)ethane] contamination ranging from 25-338 ppb (wet weight). Biotic samples
taken from the northeast region of the state nearby metropolitan areas in the Hudson-Newark-
Raritan Bay complex consistently exhibited the highest concentrations of DDT and its metabolites
DDE [l,l-dichloro-2,2-bis(p-chlorophenyl)ethyleneJ and ODD [l,l-dichloro-2,2-bis(/?-
chlorophenyl)ethane]. Among all four species examined, the highest levels of DDT contamination
(> 300 ppb FW) were documented in blue crabs (hepatopancreas) from the northeast region. All
other tissue samples analyzed for DDT had concentrations less than 200 ppb FW, which is far less
than the U.S. Food and Drug Administration action level of 5000 ppb for this contaminant. The
lowest levels of DDT contamination (< 110 ppb FW) were observed in samples collected from the
south coast region. These results are generally consistent with the findings on DDT and other
organochlorine contaminants during the 1986-1987 sampling period that also showed the
northeast region to be the most severely impacted area of the state.
DDT concentrations in bluefish and striped bass were substantially greater than in weakfish.'
Large bluefish (total length > 60 cm) contained, on average, approximately three times the level of
DDT found in small bluefish. This species accumulates DDT in lipid-rich tissues. Hence, state
advisories that limit the consumption of large bluefish should effectively reduce exposure to this
contaminant. Despite the 1972 ban of DDT for most uses in the United States, conclusions of this
study indicate that at least some commercially and recreationally important finfish and shellfish
species in New Jersey waters continue to sequester DDT, albeit at significantly lower levels than
during the 1960s and 1970s.
INTRODUCTION
DDT [l,l,l-trichloro-2,2-bis (p-chlorophenyl)ethane] and its breakdown derivatives, DDE
[l,l-dichloro-2,2-bis(p-chlorophenyl)ethylene] and ODD [l,l-dichloro-2,2-bis(/?-
chlorophenyl)ethane], are among most intensely studied chlorinated hydrocarbon compounds in
estuarine and marine environments. Both DDT and DDE exhibit great stability, persistence, and
toxicity in these environments, and hence pose a danger to many species. ODD appears to be
only moderately toxic to a limited number of organisms. Despite being banned in the U.S. in
1972, DDT is still found in various biotic and abiotic media nationwide.
DDT can rapidly impact marine food webs. Poorly metabolized by biological systems, this
lipophilic contaminant tends to accumulate in lipid-rich tissues of estuarine and. marine organisms,
where it is highly soluble. Biomagnification may result in concentrations thousands of times
greater in these organisms than the surrounding water, especially in upper-trophic-level
carnivores. Consequently, government agencies have closely monitored DDT levels, as well as
the concentrations of other organochlorine contaminants, in finfish and shellfish, periodically
130
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releasing consumption advisories, fishing prohibitions, or bans needed to protect the seafood-
consuming public.
NEW JERSEY SURVEYS
This work examines the concentrations of DDT group compounds (DDT, DDE, and DDD)
in selected estuarine and marine finfish and shellfish species collected throughout New Jersey
during the 1986-1987 and 1988-1991 periods as part of a larger effort by the New Jersey
Department of Environmental Protection (NJDEP) to monitor levels of organochlorine pesticides
in aquatic environments. Three finfish species (bluefish, Pomatomus saltatrix, striped bass,
Morone saxatilis, weakfish, Cynoscion regalis) and one shellfish species (blue crab, Callinectes
sapidus) are considered. All are of recreational and commercial importance in the New Jersey
fishery.
Sampling locations in this investigation were grouped into five geographic regions (Table 1,
Figure 1): (1) northeast (sites within the Hudson, Raritan, Hackensack, and Passaic River
drainages); (2) north coast (all ocean sites and estuarine sites between Sandy Hook and Seaside
Park); (3) south coast (all ocean sites and estuarine sites between Sandy Hook and Seaside Park);
(4) Atlantic (site 46 off Barnegat Inlet selected to represent the entire Atlantic coastline from
Sandy Hook to Cape May for bluefish); (5) and Delaware (sites on the main stem of the Delaware
River, tributaries to the river excluding the Camden area, and tributaries to Delaware Bay).
Finfish and shellfish samples were collected by gill net, otter trawl, seine, hook and line, baited
trap, and crab pot Some samples (i.e., bluefish, weakfish, striped bass) were obtained from
recreational and commercial fishermen.
LABORATORY METHODS
Finfish and shellfish samples were analyzed for DDT group compounds according to
established government guidelines. Homogenized tissue samples were extracted and quantified by
gas chromatography at the New Jersey Department of Health laboratory employing a Tracer
model 222 gas chromatograph with an electron capture detector. Methods of the U.S.
Environmental Protection Agency (1980) for pesticide analysis were applied with slight
modification in the initial tissue preparation and extraction sections. Ten grams of tissue were
soxhlet-extracted for six hours in a 3:1 hexane-acetone mixture. The extract was then isolated
and cleaned up using gel permeation chromatography. The final extract was concentrated,
characterized by gas chromatography, and quantified by comparison with standards for p,p'-DDT,
p,p'-DDE, and p,p'-DDD. Detection limits were 5 ppb for p,p'-DDE, and 10 ppb for p.p'-DDD
and p.p'-DDT. Quality control followed U.S. Environmental Protection Agency guidelines (U.S.
Environmental Protection Agency, 1976).
RESULTS
The highest concentrations of DDTs during the 1988-1991 period occurred in samples
collected from the northeast and north coast regions (Table 1). For example, the mean
concentration of DDTs in bluefish and blue crabs peaked in the northeast region, amounting to
168.32 ppb fresh weight (FW) in bluefish and 338.30, 143.30, and 38.83 ppb (FW) in blue crab
hepatopancreas, hepatopancreas-muscle mixture, and muscle, respectively. The concentration of
DDTs in striped bass and weakfish was highest in the north coast region, with mean values of
151.40 and 84.08 ppb FW, respectively. These data are consistent with results of previous
investigations of New Jersey waters, which show areas in the northern part of the state to be the
most severely contaminated with organochlorine compounds (Hauge et aL, 1993; Kennish et aL,
1992; Kennish & Ruppel, 1995).
During the 1986-1987 sampling program, the highest concentration of DDTs were
observed in blue crab (hepatopancreas) samples from the northeast region, with residue burdens
averaging 492.52 ppb FW. Substantially lower levels of DDTs were found in bluefish, striped
bass, and weakfish from the northeast region at this time, amounting to 101.86, 189.39, and 64.16
ppb FW, respectively. Peak concentrations of DDTs in bluefish (mean = 104.35 ppb FW) and
striped bass (mean =193.94 ppb FW) were recorded in the north coast region during the 1986-
1987 period, while the highest concentrations of DDTs in weakfish (mean = 64.16 ppb FW) were
registered in the northeast region.
131
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Large bluefish (> 60 cm in length) contain, on average, nearly three times the concentration
of DDTs than small bluefish (< 60 cm). During the 1988-1991 sampling period, for example, the
mean concentration of DDTs in bluefish > 60 cm in length (147.59 ppb FW) was significantly
greater than in bluefish < 60 cm (46.26 ppb FW). Since large bluefish have a higher lipid content
than small bluefish, they also tend to sequester greater amounts of DDTs in their tissues.
Despite gradual decreases in DDT concentrations in estuarine and marine biota in recent
years, the results of the most recent monitoring program (1988-1991) indicate persistent
widespread occurrences of DDT group compounds above background levels in the edible
portions of some species from different areas of the state. This is particularly evident in lipid-rich
finfish species, such as bluefish and striped bass, as well as susceptible shellfish such as the blue
crab. Hence, the existing framework of consumption advisories, crabbing prohibitions, and sales
bans formulated by the NJDEP provides an effective strategy for protecting the public from
excessive exposure and biomagnification effects of organochlorine contaminants found in
estuarine and coastal marine finfish and shellfish. This framework may also protect the seafood-
consuming public from exposure to other contaminants in the biota as well.
ACKNOWLEDGEMENTS
This is New Jersey Agricultural Experiment Station Publication No. H-32402-1-95 and
Contribution No. 95-14 of the Institute of Marine and Coastal Sciences, Rutgers University,
supported by New Jersey State funds and the Fisheries and Aquaculture Technology Extension
Center.
REFERENCES
Hauge, P. (1993). Polychlorinated biphenyls (PCBs), chlordane, and DDTs in selected fish
and shellfish from New Jersey waters, 1988-1991: Results from New Jersey's Toxics
in Biota Monitoring Program. New Jersey Department of Environmental Protection and
Energy Technical Report, Trenton, New Jersey, 95 p.
Kennish, M. J., Helton, T. J., Hauge, P., Lockwood, K. & Ruppel, B. E. (1992).
Polychlorinated biphenyls in estuarine and coastal marine waters of New Jersey: A
review of contamination problems. Rev. Aquat.Sci., 6, 275-293.
Kennish, M. J. & Ruppel, B. E. (1995). PCB contamination in selected estuarine and coastal
marine finfish and shellfish of New Jersey. Estuaries (in press).
U.S. Environmental Protection Agency. (1976). Manual of analytical quality control for
pesticides in human and environmental media. EPA 600/1-76-017, Health Effects
Research Laboratory, Research Triangle Park, NC.
U.S. Environmental Protection Agency. (1980). Manual of analytical methods for analysis of
pesticides in human and environmental samples. EPA 600/8-80-038 Health Effects
Research Laboratory, Research Triangle Park, NC.
132
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TABLE 1. Mean concentrations of DDTs by region in selected estuarine ,
and Mrine finfish and shellfish from 1988-1991 (from Hague. 1993). •*
Region
Species Delaware North Coast Northeast South Coast Atlantic
Blue
Crab
IT*
*
H-M5
Bluefish
Striped
Bass
Weakfish
64.84
(1)
25.19
(1)
39.65
-
•
-
36.57
(4)
25.14
(4)
28.38
(4)
93.18
(6)
151.40
(18)
84.08
(6)
338.29
(7)
38.35
(7)
143.30
(9)
168.32
(6)
146.90
. (14)
37.80
(2)
"
-
25.19
(2)
100.73
(8)
110.46
(17)
60.74
(30)
"
•
•
145.38
(14)
•
•
Values in ppb, fresh weight
Number in parentheses * number of data points
Hepatopancreas
Sluscle
Hepatopancreas-Nuscle Mixture
Table 1
133
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17
20 CAMDEN
(17-23)
DELAWARE
(24-31)
NORTH COAST
(32,33,37, 37A,38,44,45)
37A
38A
SOUTH COAST
(34-36, 38A,39-42,43)
Figure 1. Biotic sampling sites for the DDT monitoring program in New Jersey during the
1986-1987 and 1988-1991 periods (from Hauge, 1993).
134
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THE USE OF CIS AND REMOTE SENSING IN COASTAL RESOURCE
MANAGEMENT
Victor V Klemas and Oliver P. Weatherbee
College of Marine Studies
University of Delaware
Newark, Delaware 19716
Geographic Information Systems (GIS) and digital data base techniques are providing
environmental scientists and resource managers with an effective means for performing landscape
scale ecological studies and solving resource protection and development problems. Specifically,
GIS enables scientists to link theoretically oriented ecological models with applications in
resource planning and management.
The GIS approach is particularly effective when used with remotely sensed data as input
and Global Positioning Systems (GPS) for field verification and accuracy assessment. Remotely
sensed data has been used as input to watershed models to relate land use changes in watersheds
to non point source pollutant run-off, distribution, concentration and impact on living marine
resources in estuaries and coastal waters (Figure 1). The integration of image data into a GIS has
recently become feasible. There has always existed the need for such data as maps and ground
surveys in helping to analyze remotely sensed data. GISs have also had a need for remotely
sensed data to correct, update, and maintain their cartographic data bases.
A GIS is a collection of software and hardware used to acquire, sort, and manipulate geo-
referenced data (Table 1). The central focus of a GIS is the manipulation and analysis of spatial
data, and although it is involved with such endeavors as regional research, policy analysis and
planning, its capabilities also include procedures for modeling and elaborate cartographic displays.
Remote sensing has been shown to be an efficient and cost effective means of providing needed
data for input and updating GIS data bases It is widely known that a major cost of GIS
operation involves the acquisition of georeferenced data. The use of remote sensing increases
GIS accuracy and helps update the database. Thus, relationships which exist between remote
sensing and GIS are highly synergistic. Remote sensing allows one to map land cover and other
variables, while GIS, with its cartographic data base, allows the organization and analysis of these
measurements.
Coastal applications of GIS are particularly effective because GIS techniques are amenable
to monitoring natural and anthropogenic changes taking place in the coastal zone. Examples of
successful applications to solve coastal problems are shown in Table 2, including offshore oil
spills, release of land-borne pollutants into the sea and coastal erosion. Table 3 summarizes
successful applications of GIS techniques to a wide range of coastal problems by the states of
Florida, Alaska and Louisiana. Difficulties encountered using GIS techniques in the coastal zone
are summarized in Table 4. Note that the most difficult problems faced by GIS users in coastal
areas are the lack of an accurate, up-to-date shoreline definition, lack of good bathymetric base
maps, and the cost of digitizing and geo-referencing aerial photographs, maps and other non-
digital data
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Table 1
ESSENTIAL ELEMENTS OF A CIS
1 DATA ACQUISITION
Identifying and gathering maps, images, attribute data, etc.
Accuracy, correct identification and location.
2 DATA PROCESSING
Screening, digitizing and scanning, scale adjustment, error detection, editing, edge
matching, etc.
3. DATA MANAGEMENT
Data entry, upgrade, deletion, retrieval.
Superimpose layers of data to create new layer (map).
4 DATA MANIPULATION AND ANALYSIS
Analytic operators work with data base to derive new information; measurement, statistical
analysis, modeling, spatial operations, reclassification, aggregation, etc.
5. PRODUCT GENERATION
Maps, bar-graphs, scatter plots, pie charts, histograms, etc.
Hard copy (map on paper or film)
Soft copy (computer display, etc.)
Table 2
COASTAL APPLICATIONS OF CIS TECHNOLOGY
(Examples)
OFFSHORE OIL SPILL
• Where are the nearest clean-up resources and how long will it take for them to arrive at the
spill site?
Where are the resources during clean-up?
What is the dispersion rate of the spill?
What beaches, wildlife, and fisheries are threatened?
What are the losses to the "stakeholders"?
Which beaches should be cleaned first based on threat of additional loss?
RELEASE OF LAND-BORNE POLLUTANTS INTO THE SEA
Could time release of the pollutants reduce their environmental threat?
What is the effect on wildlife and fisheries?
How does the plume move and disperse at different times of day?
Do heavy metals concentrate in certain locations on the sea floor?
COASTAL EROSION
How has the coastline changed over the years? Is it cyclical or progressive?
Have containment measures such as jetties and dikes been employed?
What are the economic effects of shoreline ablation?
What are the effects to the ecosystem?
What is the anticipated future course of shoreline change?
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Table 3
EXAMPLES OF COASTAL APPLICATIONS OF CIS BY STATES
FLORIDA (Florida Marine Research Institute and Federal Agencies)
• Marine Mammal Research (Manatee Habitat) •
• Boat and Diver Use Patterns in the Florida Keys (Reef Carrying Capacity)
• Fisheries Management (Shrimp Closure and Management)
• Oil Spill Planning and Response (Clean-up, Damage Assessment, etc.)
• Site Selection for Testing of Explosives (Navy Mine Cleaning)
ALASKA (State and Federal Agencies)
• State Coastline for Oil Spill Planning and Response
• Alyeska Pipeline Spill Contingency Plan
• Fisheries Research (Fish Habitat and Evaluation)
• Sea Otter Research (Oil Spill Injury to Sea Otters)
LOUISIANA (State Agencies and Universities)
• Wetland Habitat Changes (Flora and Fauna)
• Coastal Change (Shoreline and Bathymetry)
Table 4
CIS COASTAL APPLICATION PROBLEMS
1. Shoreline poorly defined or outdated. (USGS and NOAA have different shoreline
definitions.)
2. Good basemaps not available on water side of shoreline (e.g., topographic or bathymetric
maps).
3. Ship data (water), field data (land), and satellite data have different accuracies, sampling
periods and grids, etc.
4. Data sets have drastically different formats — difficult to integrate into single GIS data base.
5. Digitization and geo-referencing of data very time consuming and costly.
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u>
00
Water
Mode
— Land I
-Vegett
Soil P
— Etc.
i ^
shed L — ' —
•Is ( Runoff ^^)
Jse
ition Cover
operties
Hydrod
Mod
— Tidal (
-Local
— Fronts
— Surfa<
Surfai
Tempi
—Wind
— Etc.
\
ynamic I . 1 . *
Bis C Distribution ^
Circulation
Currents
>, Plumes
:e Salinity
:e Water
erature
Fields
Water Quality
Models
' \^~~~
\ ''
Living Resources J-—
Models ( Impact on Living
V Marina PAcniirrnn
i
— Light Attenuation
— Susp. Sediments
—Chlorophyll
—Pollution Plumes
— Dredging
—Water Temperature
— Etc.
^ — . —**
Habitat Quality
Variables
_ Wetlands and
Marsh Productivity
— Hydroacoustic
Stock Assessments
— SAVs
Fixed Platform
Remote Sensing
from Bridges
— Etc.
Figure 1. Examples ol remotely sensed data used in watershed, hydrodynamic. water quality and living resource models.
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IMPROVING THE ENVIRONMENTAL MANAGEMENT OF DREDGING PROJECTS
IN SHALLOW WATER HABITAT
Jonathan M. Kurland, Eric P. Nelson, and Mary A. Colligan
NOAA / National Marine Fisheries Service
Habitat and Protected Resources Division
One Blackburn Drive
Gloucester, MA 01930
INTRODUCTION
Dredging is one of the most common types of development-related activities that affects
shallow water habitat, and it is also one of the least understood in terms of its environmental
effects. In this paper, we discuss the kinds of environmental impacts associated with dredging,
the distinction between maintenance and new dredging using three case studies, and a few
straightforward steps that can be taken to improve environmental management of dredging
projects.
PERMITTING AND REVIEW OF DREDGING PROJECTS
Two types of dredging projects are subject to environmental review at the federal level:
permit projects authorized by the U.S. Army Corps of Engineers under Section 10 of the Rivers
and Harbors Act of 1899, and civil works projects conducted by Corps to maintain federal
navigation channels and anchorages. The National Marine Fisheries Service's Habitat
Conservation Program reviews both of these types of projects and provides recommendations to
the Corps of Engineers on ways to avoid or minimize potential impacts to living marine resources
and their habitats.
Apart from this administrative distinction between private and federal dredging projects, a
technical distinction is helpful for purposes of assessing environmental impacts. In this respect,
the two types of dredging project are maintenance dredging (which is the repeated dredging of an
area to the same depth) and new dredging (defined as dredging in new areas or to deeper depths
than before). In either case, the National Marine Fisheries Service typically is concerned with
both short-term and long-term effects to shallow water habitats. Short-term effects may include
impacts to spawning activity, eggs, larvae, and recruitment, primarily due to localized turbidity
and sedimentation. Long-term effects can include habitat alteration and the loss of valuable
resources such as seagrass meadows or shellfish beds.
WHAT'S THE DIFFERENCE BETWEEN NEW AND MAINTENANCE DREDGING?
In general, the environmental impacts of regular maintenance dredging are not particularly
serious. Maintenance dredging involves the repeated disturbance of a dynamic environment. In
such areas there is a rapidly accreting bottom, so the substrate and contours change fairly quickly
and benthic communities do not have an opportunity to develop and mature between dredging
cycles. These areas are also subject to existing vessel activity and associated impacts.
New dredging, on the other hand, generally has a greater potential for serious impacts.
New impacts in previously undisturbed sites alter the physical environment that has stabilized to
prevailing conditions such as tidal flushing, currents, and substrate type The biological
community in such areas has adapted to these conditions, which increases the possibility for
dredging conflicts with seagrass, shellfish beds, spawning habitat, and other valuable resources.
Increased vessel activity due to new dredging is another source of potential habitat disturbance.
These generalizations are useful, but problems often arise when the distinction between
"new" and "maintenance" dredging becomes blurred. Such ambiguous situations arise when a
project characterized as "maintenance dredging" is not truly a case of regular maintenance,
because the environmental impacts from infrequent maintenance are similar to the impacts from
new dredging. Three case studies help to illustrate these points: dredging projects in
Swampscott Harbor, Massachusetts, York Harbor, Maine, and Little Harbor, New Hampshire.
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SWAMPSCOTT HARBOR, MASSCHUSETTS
The Swampscott Harbor dredging was a permit project that began in 1992 with an
application by the Town of Swampscott and the Massachusetts Department of Environmental
Management to maintenance dredge two areas in Swampscott Harbor. The areas had last been
dredged in 1958, nearly 35 years before. The harbormaster reported that there were no shellfish
or eelgrass beds within dredge area, and the Corps of Engineers project manager saw no
resources of concern during a brief site visit from shore. Based on this information, the National
Marine Fisheries Service had no objections to the project.
Shortly after the work began, the dredging contractor expressed concern that he was
dredging through eelgrass and that his work orders specified dredging outside the area depicted
on the 1958 dredge plans. A subsequent dive survey revealed that extensive eelgrass beds were
present throughout the project area. In other words, although the project was characterized as
"maintenance," the contractor had been instructed to dredged through well-developed subtidal
habitat and to do work in areas that had not previously been dredged.
The project resulted in the loss of approximately two acres of eelgrass, and the Corps of
Engineers later agreed that this incident exposed flaws in the permit review process since
important subtidal habitats were not afforded the same level of review that typically is applied to
terrestrial habitats. In summary, the issues raised by this example include inadequate review to
verify the limits of maintenance dredging, inadequate resource surveys, and a long interval since
the last dredging (35 years) during which valuable biological resources had developed.
YORK HARBOR, MAINE
The York Harbor dredging was a federal civil works project proposed in 1994 involving
two federal anchorages that were last dredged more than twenty years before. After the area
slowly shoaled in over this long period, an eelgrass bed developed on one side of the south
anchorage. The remainder of the anchorage was relatively featureless with a silty mud bottom,
and did not contain eelgrass.
The National Marine Fisheries Service learned about the eelgrass late in the review process
for the project, and conducted a dive survey to document the areal extent of this resource.
Although the Corps of Engineers contended that the direct impacts of the dredging would be
small (about 6500 square feet of eelgrass loss), we determined that the indirect impacts would be
substantial due to slumping of side slopes, over-dredge, sedimentation, turbidity, and the
imprecise nature of dredge operations. Our assessment concluded that the project would destroy
virtually the entire eelgrass bed, totaling about 0.75 acres. The environmental functions and
values of concern in this case were habitat for juvenile and newly shed lobsters (especially given
the lack of refuge habitat in the surrounding area) and wave baffling and erosion control for a salt
marsh adjacent to the anchorage.
This situation was further complicated by the policy of the Corps of Engineers Navigation
Division not to provide compensatory mitigation for unavoidable impacts associated with federal
civil works projects. Also, we were concerned that even if the Corps did provide mitigation, it
might not offset the impacts of the project because the eelgrass bed had site-specific benefits and
because mitigation always involves technical uncertainties.
Instead, we recommended that the Corps avoid dredging the eelgrass and leave a 30 to 50
foot buffer zone around the bed. Given that the town had already proposed to realign the dredge
area to avoid conflicts with existing piers in the anchorage, we argued that a similar modification
was warranted to protect valuable shallow water habitat. Fortunately, through negotiations
between the National Marine Fisheries Service, the Corps, and the town, we reached agreement
on a modified buffer zone that should protect most of the eelgrass habitat. However, despite the
happy ending for this project, larger problems remain: inadequate project management that does
not always attempt to solve environmental problems, the Corps' policy not to provide
compensatory mitigation, and the tough resource management issues raised by infrequent
maintenance dredging.
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LITTLE HARBOR, NEW HAMPSHIRE
The Little Harbor dredging was another proposed federal navigation project, and involved
maintenance dredging to -12 feet mean low water a channel 3,000 feet long by 100 feet wide and
an adjacent 40 acre anchorage. These areas have not been dredged since they were first
authorized by Congress in 1903, so this project would be the first "maintenance" in nearly a
century.
The initial proposal in 1994 involved dredging only a portion of the channel that had
shoaled, but the Corps of Engineers was also investigating the feasibility of a larger future project.
However, given the length of elapsed time since the harbor was originally dredged, the area had
gradually recovered to conditions that were probably quite similar to the shallow water
environment that existed naturally. Today, resources commonly found in Little Harbor include
eelgrass, lobsters, smelt, winter flounder, soft-shelled clams, and striped bass.
The Corps of Engineers Navigation Division considers the Little Harbor project (and any
other area they have previously dredged) to be maintenance dredging, and it is unlikely that they
would consider compensatory mitigation for any unavoidable impacts of the project. However,
the habitat concerns with this project include both short-term impacts (i.e., disturbance for
resident fish and shellfish communities) and long-term impacts deepening the area so that eelgrass
could not reestablish and encouraging increased boat activity (i.e., associated pollutant
discharges). The central concern with this type of project is that natural shallow water systems
recover very slowly from major perturbations like dredging, and new impacts from infrequent
"maintenance" dredging tend to be severe, especially after 20, 35, or in this case, more than 90
years. For civil works projects, this also calls into question the purpose and need for dredging,
since maintenance of Congressionally authorized navigation projects does not require the same
rigorous public interest review process that new projects are afforded.
IMPROVING THE ENVIRONMENTAL MANAGEMENT OF DREDGING PROJECTS
These three case studies help to illustrate some of the difficulties involved in environmental
reviews of seemingly non-controversial maintenance dredging projects. It might appear that an
easy answer is for harbors to be dredged more frequently so that dredged basins do not have an
opportunity to revert to productive shallow water habitats. However, the real question here is
how to manage the environmental issues that can and will emerge when dredging projects are
maintained on long time cycles due to slow accretion rates, funding limitations, or other reasons.
We have five recommendations.
First, there is a strong need for a more consistent process for the identification and
delineation of environmental resources in shallow marine and estuarine habitats. The National
Marine Fisheries Service is pursuing this need in New England through the development of a new
two-tiered resource assessment policy for permit projects. Tier 1 involves a reconnaissance level
assessment that raises public awareness of shallow subtidal concerns by requiring applicants to use
available information sources to determine what resources are present in the project area. Tier 2
requires a more detailed assessment for new dredging projects and maintenance projects that have
not been dredged in the past ten years, including structured shellfish and seagrass surveys where
warranted. It may be useful to adopt similar standards in other regions so that important subtidal
resources do not go unnoticed.
Second, environmental assessments of dredging projects can be improved by expanding the
review of pre- and post-dredge surveys. This analysis can help to verify that "maintenance"
dredge areas have been dredged before, and provides another mechanism for ensuring that all
environmental resources are identified before dredging projects begin.
Third, a very basic step for solving environmental problems associated with dredging
projects is to encourage thorough coordination and project management. Dredging projects
involve diverse issues and numerous interested parties, and it is important to provide a forum for
addressing all relevant concerns. Good project management also means involving pertinent
resource agencies early to ensure that field work is done at the right seasons and using the proper
methods.
Fourth, increased permit monitoring and compliance review can confirm that permit
applicants and contractors follow their permit conditions and only do the work that is authorized.
As with other types of coastal construction, lack of oversight and compliance can easily foil the
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best efforts of scientists and resource managers to develop sound recommendations and permit
conditions.
Finally, we see a strong need for enlightened planning of Corps of Engineers civil works
projects. Permit applicants are required to go to great lengths to address environmental issues on
the local, state, and federal level. Federal navigation projects are not different from permit
projects in terms of their potential to affect shallow water habitats, so the Corps should follow the
same standards. In particular, it is critical for these projects to demonstrate a clear purpose and
need for dredging, to avoid and minimize aquatic impacts through the analysis of reasonable
project alternatives (e.g., modified dredge footprints), and to provide adequate compensatory
mitigation for any remaining unavoidable project impacts.
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MONITORING LAND COVER CHANGE IN NEW JERSEY'S COASTAL ZONE
ACROSS A GRADIENT OF HUMAN DISTURBANCE
Richard G Lathrop, Jr. Ph.D
Department of Natural Resources
Rutgers University
New Brunswick NJ 08903-0231
Kenneth Able,. Ph.D.
Institute of Marine and Coastal Sciences
Rutgers University Marine Field Station
Tuckerton, NJ 08087
ABSTRACT
The Rutgers University Center for Remote Sensing and Spatial Analysis, in cooperation
with the NOAA, has initiated a Coastal Change Analysis Project (C-CAP) for New Jersey. Using
established C-CAP protocols, newly acquired (fall 1994) Landsat Thematic Mapper imagery is
being classified to provide a baseline survey of coastal wetland and upland habitats for the Outer
Coastal Plain region of New Jersey to serve as the basis of future C-CAP change detection
efforts. In addition, we are undertaking a retrospective change detection for the Barnegat Bay
region using Landsat Thematic Mapper (TM) imagery from 1984 to 1994. The Barnegat Bay
case study will demonstrate the applicability of remote sensing change detection techniques to
local and regional planning and management efforts in New Jersey. Application of the NOAA C-
CAP protocols for land cover classification and change detection in New Jersey will provide a
useful comparison with other coastal regions in the United States.
INTRODUCTION
New Jersey's coastal zone has experienced tremendous development in the last two
decades. The loss of coastal wetland and upland habitat and the increase in nonpoint source
pollution has negatively affected adjacent estuarine systems, leading to a decrease in productivity
and biodiversity. In an attempt to halt and even reverse this trend of coastal degradation, a
remarkable number of efforts have been initiated in the state of New Jersey at all levels of
government.
To provide feedback to these various local, state and federal agencies concerned with the
success or failure of habitat management policies, the Rutgers University Center for Remote
Sensing and Spatial Analysis has initiated a cooperative Coastal Change Analysis Program (C-
CAP) project for the Outer Coastal Plain of New Jersey. As a crucial first step, a standardized
baseline survey of land cover is being undertaken in this important coastal region. In addition, we
will undertake a retrospective change detection using Landsat Thematic Mapper (TM) imagery
from 1984 and 1994 for the Barnegat Bay/Great Bay Region, an area known to have undergone
extensive land cover change. This paper describes the scope and objectives of this ongoing
project.
OBJECTIVES
The overall goal of this project is to develop a standardized information base on the present
land cover of New Jersey's Atlantic Outer Coastal Plain to serve as the basis of future C-CAP
change detection efforts. To demonstrate the utility of remotely sensed change detection
techniques to state and local management agencies, we will undertake a retrospective change
detection in the Barnegat Bay/Great Bay Region.
STUDY AREA
New Jersey's Outer Coastal Plain is a distinct physiographic region that stretches from
Sandy Hook on the Atlantic Ocean diagonally southwest across the state to the upper reaches of
Delaware Bay (Figure 1). The study region, approximately 9100 km2 in area, spans substantial
portions of two Landsat TM scenes (Path/Row 14/32 and 33). The study area can be delineated
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into three major zones: 1) Atlantic Ocean coast; 2) Delaware Bay coast; and 3) Pinelands interior.
The Atlantic coastal portion includes coastal barrier island, back-bay lagoons, coastal salt marsh,
forested uplands/wetlands, and urban/residential areas. The Delaware Bay portion includes
extensive areas of salt marsh and mixed crop agriculture. The interior of the study area is
dominated by the New Jersey Pinelands which is characterized by a complex mosaic of forested
uplands and wetlands, intermixed with cranberry and blueberry agriculture. The Barnegat Bay-
Great Bay (BB-GB) subarea spans a gradient from higher population and development densities
in the north portion of Barnegat Bay to the comparatively undeveloped Great Bay in the south
(Figure 1).
METHODS
Standard C-CAP protocols (Dobson et al., 1995) are being used to provide for a land cover
data base consistent with those developed in other C-CAP projects. Landsat TM imagery
(Path/Row 14/32 & 14/33) has been acquired for a cloud-free date in November, 1995 (Nov. 4,
1995). This imagery known as "leaf-off" occurs after normal deciduous plant leaf fall, thus
allowing the clearer differentiation of evergreen vs. deciduous forests. For the change detection
efforts, a corresponding image from November 8, 1984 has been acquired. This "anniversary"
image will allow us to quantify the change in land cover that has occurred during the ten-year
period between 1984 and 1994.
A "ground-truthing" field campaign has been undertaken during the fall of 1994 and
winter/spring months of 1995. A number of representative USGS quadrangle areas were selected
throughout the study region to get a representative sample and not bias the classification to any
particular subarea. Site locations within each quadrangle were randomly located. Over 200 field
sites have been visited to serve as classification training and accuracy assessment. Reconnaissance
field sampling at each site included ocular estimates of percent cover of each land cover type,
vegetation stratum (i.e., tree, shrub, herb) and ground photos. A differential Global Positioning
System (GPS) receiver was used to geo-reference the training site locations. High altitude color
infrared aerial photography (acquired March 1991) is being used to supplement the ground
reference data.
The TM imagery has undergone a number of pre-processing steps. The TM imagery has
been rectified to a Universal Transverse Mercator coordinate system using ground control points
(e.g., road intersections) from USGS 1:24,000 scale topographic quadrangle maps. A registration
criterion of RMSE of < +0.5 pixels was used. The TM data were resampled using a nearest
neighbor technique. To correct for first-order atmospheric differences between different dates of
imagery (e.g., 1984 to 1994), image normalization techniques (e.g., Eckhardt et al., 1990) have
been used. Suitable normalization targets include "dark pixels" such as deep non-turbid water
reservoirs (used in cranberry bog agriculture) and "bright pixels" such as white sand beaches and
gravel pits.
A combination of unsupervised and supervised approaches are being used to classify the
corrected Landsat TM image using the ERDAS image processing software. As demonstrated in
other studies of the application of remote sensing for forest vegetation classification, one channel
from the visible spectrum, near IR and middle IR is needed to adequately characterize the
vegetation (Iverson et al., 1989). A multispectral approach is also needed to properly dicriminate
and classify wetland communities (Jensen et al., 1986; Hardisky et al., 1986). Unsupervised
statistical clustering algorithms have been used to determine preliminary spectral clusters. The
"unsupervised" clusters are being supplemented with representative "supervised" training sites.
The standard C-CAP classification category scheme (Klemas et al., 1993) is being used.
Incorporation of additional data sets in the context of a geographic information system
(GIS) to provide further classification improvement will be investigated. Previous experience in
classifying New Jersey wetland communities has shown that spectral data alone is insufficient to
adequately characterize certain land cover types (Lathrop, 1994). For example, upland deciduous
forests dominated by oak (Quercus species) are often spectrally indistinguishable from lowland
deciduous forests dominated by maple (Acer rubrurri). Dense canopies of phragmites are also
spectrally similar to closed forest canopies. Collateral data such as National Wetland Inventory
(Cowardin et al., 1979) and/or soil type data (e.g., hydric soils derived from county level soil
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survey maps) will be incorporated into the classification process, serving as a mask to delineate
wetland vs. upland habitats.
For the retrospective change analysis, we will use the multi-date change detection algorithm
using a binary change mask applied to Date 2 (e.g., Jensen et al., 1993). The 1994 classified land
cover map will serve as the baseline Date 1. A two-band data set including one from the base line
(e.g., band 5 or a band ratio such as 4/3 or (4-3)7(4+3)) from the baseline and one from the
change date will be created. Image differencing and band ratioing will be used to create a binary
change mask. "Change/no change" threshold boundaries will be determined empirically based on
knowledge of the study area as well as historical aerial photographs and other land cover mapping
efforts undertaken in the 1980s. Only those areas deemed to have changed will then be classified.
A "from-to" matrix (e.g., a transition matrix) detailing the types of changes observed will be
produced.
SUMMARY
Using established C-CAP protocols, 1994 Landsat Thematic Mapper imagery will be
classified to provide a baseline survey of coastal wetland and upland habitats for the Outer
Coastal Plain region of New Jersey to serve as the basis of future C-CAP change detection
efforts. Application of the NOAA C-CAP protocols for land cover classification and change
detection in New Jersey will provide a useful comparison with other coastal regions in the United
States. This C-CAP project will complement ongoing efforts by the principal investigators and
others to describe and analyze relationships between estuarine habitat amount, water quality and
biodiversity along a gradient of human disturbance from Barnegat to Great Bay.
ACKNOWLEDGMENTS
This project is funded by the NOAA Coastal Change Analysis Program through the NJ
Marine Sciences Consortium, Project #R/S-32. The assistance of John Bognar in various phases
of image data processing and graphics production has been invaluable. This work is being
conducted using the facilities of the Rutgers University Center for Remote Sensing and Spatial
Analysis.
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REFERENCES
Cowardin, L.M. V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands
and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service.
FWS/OBS-79-31. 103pp.
Dobson, I.E., E.A., Bright, R.L. Ferguson, D.W. Field, L.L. Wood, K.D. Haddad, H.
Iredale, J.R. Jensen, V.V. Klemas, R.J. Orth, J.P. Thomas. 1994. NOAA Coastal
Change Analysis Program (C-CAP): Guidance for Regional Implementation. NOAA
Technical Report NMFS 123. 92 p.
Eckhardt, D.W., J.P. Verdin, and G.R. Lyford. 1990. Automated update of an irrigated lands
GIS using SPOT HRV imagery. Photogrammetric Engineering and Remote Sensing 56:
1515-1522.
Hardisky, M.A., M.F. Gross and V. Klemas. 1986. Remote Sensing of Coastal Wetlands.
BioScience 36:453-467.
Iverson, L.R., R.L. Graham and E. A. Cook. 1989. Applications of Satellite Remote Sensing to
Forested Ecosystems. Landscape Ecology 3:131 -143.
Jensen, J.R., M.E. Hodgson, E. Christensen, H.E. Mackey, Jr., L.R. Tinney and R. Sharitz.
1986. Remote Sensing of Inland Wetlands: A Multispectral Approach. Photogrammetric
Engineering and Remote Sensing 52:87-100.
Jensen, J.R, D.J. Cowen, J.D. Althausen, S. Narumalani, and O. Weatherbee. 1993. An
evaluation of the Coast.watch Change Detection Protocol in South Carolina.
Photogrammetric Engineering and Remote Sensing 59:1039-1046.
Klemas, V., J.E. Dobson, R.L. Ferguson, and K.D. Haddad. 1993. A coastal land cover
classification system for the NOAA CoastWatch Change Analysis Project. Journal of
Coastal Research 9:862-872.
Lathrop, Richard G. Jr. 1994. Satellite Remote Sensing of Pinelands Ecosystems. Bartonia
58:1-9.
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Retrospective Change Detection
Study Area
New Jersey
Area of Detail
Outer Coastal Plain
1 Barnegat Bay
2 Little Egg Harbor
3 Great Bay
Road network source: TIGER
Figure 1
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BENTHIC PRIMARY PRODUCTION WITHIN SHALLOW WATER SITES IN
CHESAPEAKE BAY
Susanne Wendker, H.G. Marshall and K.K Nesius
Department of Biological Sciences
Old Dominion University
Norfolk, Virginia U.S.A. 23529-0266
FAX 1-804-683-5283
ABSTRACT
Primary production of the microbenthic algal community represents a year-round
contributor to the total productivity in Chesapeake Bay with an annual rate of 142.4 gCm2yr~1.
INTRODUCTION
Primary production associated with the benthic flora of shallow water habitats represents a
significant contribution to the total productivity in shallow water estuaries; yet, this measurement
is often omitted in productivity studies. A significant component of this community is the
microbenthic algae which Charpy-Roubaud and Sournia (1990) estimate to have an average
production of 100 gCm^r"1 for the shallow areas of the world's oceanic waters. Along the United
States east coast these productivity rates have ranged from 56 to 250 gCM2^'1 (Pinckney &
Zingmark, 1993). The objective of this study was to determine the primary production by the
microbenthic algal community at tidal mudflat sites in Chesapeake Bay. This is a temperate
estuary with extensive shallow water areas and numerous sand and mud intertidal areas along its
shoreline.
METHODS
The study period was from April 1992 through May 1993 with 5 stations established in the
lower Bay (Figure 1). Random samples were taken monthly from the mud surface at low tide
over the tidal range of each site. The uppermost surface centimeter of sediment was obtained with
a glass sampler, added to the sample was 50^1 of 14C-Na HCO3 and then the samples were
incubated on station, with a sediment suspension from each sample subsequently analyzed in a
Beckman LSI701 scintillation counter. Carbon fixation rates (mgCm'hr"1) and annual production
rates (gCm^r"1) were determined according to Strickland and Parsons (1972).
RESULTS
The sites were covered twice daily by flood tide and alternately exposed at ebb tide. The
mean tidal range was approximated 1 m, with the sites exposed to meso- to polyhaline waters (6-
26 ppt). Carbon fixation for all stations ranged from 1.17 to 91.36 mgCm'hr' (1507.7 to 4521.6
mgCm hr"1-) with an annual mean of 28.2 mgCn^hr"1. The monthly benthic productivity rates for
the Chesapeake Bay are given in Figure 2. These are averaged rates for the 5 stations and
indicate an increase from spring to a summer peak that decreases into winter. The mean
productivity range was from a seasonal low in December of 8.6 to 49.0 mgCmV1 in August.
There was a distinct difference in these rates along a north/south gradient in the Bay. Stations 1
and 2 were located farther north and had a yearly mean of 16.7 mgCn^hr"1 Stations 3-5 located,
nearer the Bay entrance, were more productive than Stations 1 and 2 with a yearly average of
30.6 mgCmTO"1. The total annual productivity based on station averages was 142.4 gCnvV"1
A diverse diatom population dominated the benthic flora throughout the period of study.
There were 95 diatoms identified in these samples (11 centric, 84 pennate). During each month
the benthic flora was distinct from the phytoplankton components. However, different benthic
diatoms dominated seasonally at several of the stations. The more common diatoms included
Dimeregramma minor. Navicula arenaria. >L pusilla. and Opephora martyi. An increase of
cyanobacteria within the benthic flora occurred in summer with the dinoflagellates having a
sporadic presence throughout the seasons.
148
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SUMMARY
The microbenthic algal community represents a significant annual producer in the
Chesapeake Bay, as its values are estimated between 3 and 5% of the total Chesapeake Bay
annual production. The proportion of ber hie algal production to phytoplankton production
increases moving into the shallow inlets and regions of more expansive intertidal mud and sand
flats. The mean production for the microbenthos in Chesapeake Bay was 142.4-gCm2yr"1. This
rate is within the range reported for other U.S. east coast studies.
REFERENCES
Charpy-Roubaud, C. and A Sournia. 1990. The comparative estimation of phytoplanktonic,
microphytobenthic and macrophytobenthic primary production in the oceans. Marine
microbial Food Webs, 4:31-57.
Pinckney, J.L. and R.G. Zingmark. 1993. Modeling the annual production of intertidal
benthic microalgae in estuarine ecosystems. J. Phycol. 29:396-407.
Strickland, J.D.H. and T.R. Parsons. 1972. A Practical Handbook of Sea Water Analysis.
Fisheries Research Board of Canada, Bull. 167, 310 pp.
149
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Atlantic
Ocean
Figure 1. Station locations in Chesapeake Bay.
-------
Cm2 Hr'1
1992
1993
Figure 2. Mean monthly primary production rates of the microbenthic algae from stations in the Chesapeake Bay between April
1992 and March 1993.
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AMPELISCA ABDITA: THE FICKLE FIENDS OF ECOTOXICOLOGY
Amanda Maxemchuk-Daly
Aqua Survey, Inc.
499 Point Breeze Road
Flemington, NJ 08822
INTRODUCTION
Exposing marine and estuarine invertebrates to sediments in solid phase bioassays has
become a popular method for determining the relative toxicity of sediments being dredged from
coastal waterways. The estuarine amphipod Ampelisca abdita has proven to be useful for 10-day
sediment toxicity tests for which mortality is the endpoint. Because of historical success and the
ease with which the animals are collected, the use of A. abdita for bioassays has become standard.
Ampelisca abdita is more sensitive to environmental perterbation in comparison with other test
organisms. Therefore, results of tests using A. abdita are more conservative, and chemically
disturbed sediments are more likely to be accurately assessed as toxic.
Ampelisca abdita is a tube-dwelling, opportunistic animal. The life-history and life-style
characteristics of these organisms have indicated that bioassays using A abdita must be
interpreted with caution. This study had three objectives: 1) to demonstrate the seasonal
variability in the testing success (i.e., control survival) of A. abdita, 2) to demonstrate the
differences in sensitivity between populations of organisms; 3) to demonstrate the differences in
response of organisms from different populations across a variety of contaminated sediments.
BACKGROUND
. Populations of A. abdita along the southern Atlantic and Gulf coasts breed year-round.
However, populations in mid-Atlantic, New England, and Canadian estuaries have an
overwintering generation. Animals hibernate when temperatures drop below approximately 10°C
and begin breeding again in the spring when temperatures rise above 8°C (Mills, 1967). The
animals breed once during the course of their life cycle. The males expire shortly after mating,
and females expire shortly after releasing their brood (Mills, 1967). Because animals die shortly
after they mate and reproduce, it is necessary to use immature animals for bioassays. Using
juveniles for testing is also important because A. abdita is opportunistic. Juvenile animals, defined
as those between two and four millimeters in length from the base of the first antennae to the base
of the third uropod, grow rapidly to reproductive size and breed within a short period of time to
perpetuate the population. The animal's life cycle only lasts about 40 days (Mills, 1967).
Once juveniles emerge from the brood pouch, they quickly begin constructing tubes in
which they dwell and feed. Organisms will subsequently leave their tubes at night to build larger
tubes to accommodate growth, to mate, and to scatter to unoccupied areas. Scattering to
unoccupied areas reduces competition for space and possibly for food once a female releases her
brood (Mills, 1967). Due to the small size of the organisms, their basically sedentary lifestyle and
their occurrence in largely protected bodies of water, dispersal is relatively low as compared to
larger more motile species, and interaction between populations is low. From an ecological and a
regulatory standpoint, there are several species characteristics that need to be considered when
selecting a species for a bioassays. Two are of particular importance to this study:
".. .characteristics to consider for species selection for dredge material evaluations .
[include that the animals] . . are available year-round . . [and] give consistent,
reproducible response to toxicants." (Dredge Material Testing Manual, 1991)
It appears that neither of these requirements can reliably be met by A. abdita.
METHODS
Bioassays
Ten-day sediment bioassays were conducted by placing 200 mL of each test sediment in
one-Liter glass beakers. The sediments tested included control mud collected from a clean
location in Great Bay, NJ or the site from which test organisms were obtained, sand collected
from a designated reference site off of Sandy Hook, NJ, and sediments collected from various
contaminated locations in New York Harbor. Five replicate chambers were set up for each
152
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treatment (control, reference and contaminated sediment) for each bioassay, and treatments were
randomly assigned to chambers. Eight-hundred mL of seawater collected from Manasquan Inlet,
NJ at high tide was then added to each chambers. The chambers were covered with plastic petri
plate covers fixed with holes to accommodi air lines, the chambers were placed under gentle
aeration (approximately 100 bubbles/minute and the systems were allowed to settle over night.
Ampelisca abdita collected from San Francisco Bay, CA, the Narrows River, RI, Jamaica Bay,
NY or Sandy Hook, NJ had been acclimated to the desired temperature (20±2°C) and salinity
(28±2 ppt) prior to setting up the test system. Animals 2-4 mm in length were randomly selected
two at a time from a holding dish and placed in mini Carolina dishes. Once all dishes contained 20
organisms, the organisms were gently released into the test chambers.
Temperature, salinity, pH, dissolved oxygen, and total ammonia concentrations were
measured in the chambers daily over a 10-day period. Temperature was maintained between 18
and 22 °C, salinity was between 26 and 30 ppt, pH ranged from 7.3 to 8.3, and dissolved oxygen
was maintained at saturation levels.
At the end of the 10-day exposure period, animals were removed from chambers by
spraying the contents of chambers through a 0.5 mm sieve. Mortality was determined by
enumerating the live organisms removed from each test chamber.
The survival of animals exposed to control mud was assessed for seasonal trends through
graphical analysis. Graphical analysis was also used to look at differences in the response of
organisms from different populations when exposed to the same sediments in bioassays conducted
in April of 1994. To compare the responses of animals collected from two populations of A
abdita in a four-sediment bioassay conducted in November of 1994, a two-factor analysis of
variance was used
Standard Reference Toxicant Tests
Ninety-six hour standard reference toxicant tests were conducted using cadmium chloride.
A stock solution of 250 mg/L cadmium and seawater collected from Manasquan Inlet, NJ was
used to mix five concentrations of toxicant. Seawater without toxicant was used as a control.
Three replicates of each concentration were used to conduct each test. Ampelisca abdita
collected from San Francisco Bay, CA, the Narrows River, RI or Sandy Hook Bay, NJ had been
acclimated to the desired temperature (20±2°C) and salinity (28±2 ppt) prior to setting up the test
system. Ten organisms between 2 and 4 mm in length were selected randomly and two at a time
and placed into each chamber.
Temperature, salinity, pH, and dissolved oxygen were measured in each chamber daily, and
the number of live organisms was recorded. Tests were conducted at 20°C and 28 ppt salinity.
At the end of the 96-hour exposure period, the number of live organisms in each chamber
was determined. Data were used to determine the LCJO for the batch of animals tested using the
probit and moving average methods. Data collected for the three populations tested was
maintained in an historical data base and, for the purposes of this study, compiled to compare
relative sensitivities of the three populations by analysis of variance.
RESULTS
Tests conducted from February 1991 through January 1995 were analyzed for control
survival to assess testing success across seasons. Test results were pooled for each month of each
year and the mean percent survival of A. abdita exposed to control mud was plotted (Figure 1).
No statistical analysis of the data could be performed, but graphical analysis revealed a trend
indicating that the survival of animals in control chambers was lower during the colder months of
each year. In 1991, the survival of organisms exposed to control sediment was lower in February
than in September. During 1992, control survival was lowest in January and highest in May.
Tests conducted during 1993 resulted in organisms exposed to control mud surviving better in
June than in April. Lastly, tests conducted from March 1994 through January 1995 indicated that
A. abdita exposed to control mud survived better in the warmer months of April, July, August,
September and October relative to the colder months of March, November, December and
January. Tests conducted in June had unexplainably low testing control survival, as well, but the
trend for greater survival of animals exposed to control mud during warmer months is still
apparent. Variability in control survival was higher during the colder months, also.
153
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A set of tests conducted in April of 1994 revealed differences in the responses of A. abdita
from difference populations when exposed to the same sediments. When comparing the survival
of organisms exposed to sediments A, B, C, D, E and F, the identity of which must remain
confidential, it was discovered that animals collected from Jamaica Bay, NY, the Narrows River,
RI and Sandy Hook, NJ all responded differently. Also, the response of any population across
sediments could not be predicted based on the response of any other population across sediments.
In other words, while the response of animals collected from Jamaica Bay indicated increasing
mortality of organisms exposed to sediments A, C, E, B, F, and D, the trend for the other
populations was not the same. Mortality of Rhode Island animals exposed to the same sediments
increased from sediment A to B to C to E to D to F. Yet another trend was observed for Sandy
Hook Bay animals, mortality increasing from sediment A to C to F to E to B to D, without much
difference between responses upon exposure to these sediments.
No statistical analyses of these results could be conducted because the bioassays were not
run concurrently, so a test was set up which compared two populations of animals and four
sediments collected from different locations. One sediment was control mud collected from Great
Bay, NJ, another was reference sediment collected off Sandy Hook, NJ and the other two were
from locations within New York Harbor. The results of this test revealed the same trend in
responses (Figure 3). Ampelisca abdita collected from the two different locations responded
differently when exposed to the same sediment, and the response of one population across
sediments could not be predicted based on the response of the other population. Both trends
were tested and found to be significant (F^***™ „ ,=16.1, pO.OOOl; ?K
-------
tolerance for a contaminant or suite of contaminants that also persist in that area. Because
contaminants and their concentrations vary from one area to the next, the tolerances of exposed
populations also vary. This can also explain the differences in sensitivity between populations of
A. abdita to cadmium chloride.
CONCLUSION
To continue to use A. abdita successfully for bioassays, it is necessary to develop
consistencies in testing processes to yield desired, interpretable results. The problem with
seasonal variations in testing success can be overcome in two ways. One option is to only use A.
abdita for bioassays during warmer months when a long acclimation period is not necessary. If
tests need to be conducted during colder months, another test species can be used instead. The
other option is to collect animals from populations in warmer climates. It will be necessary to find
a population in a warmer climate that has animals in high enough densities to be collected
efficiently. Because it is important to obtain consistent and reproducible results, A. abdita used
for bioassays should be collected from the same population. The population chosen for bioassays
should be used by all testing laboratories everywhere so similar results are obtained regardless of
the testing facility. It would be ideal if a laboratory population cultured and maintained by all
organism suppliers could be established. However, the success of breeding A. abdita in captivity
is limited (Redmond et. al, 1994).
Ampelisca abdita is a very useful organism for bioassays. It is a relatively sensitive species,
so the results of tests which use this organisms are conservative. Collection of the test organisms
is also easy. However, unless the proposed changes for using A. abdita are accepted and
enforced by private and regulatory bodies, tests which employ this amphipod may yield
uninterpretable results.
REFERENCES
Evaluation of Dredge Material Proposed for Ocean Disposal (Testing Manual). 1991
Environmental Protection Agency, Office of Marine and Estuarine Protection,
Washington, D.C. and Department of the Army, United States Army Corps of
Engineers, Washington, D.C. EPA Contract No. 68-C8-0105.
Mills, E.L. 1967. The biology of an Ampeliscid amphipod crustacean sibling species pair.
Journal of the Fisheries Research Board of Canada, 24: 305-556.
Redmond, M.S., K.J. Scott, R.C. Swartz and K.P. Jones. 1994. Preliminary jculture and life-
cycle experiments with the benthic amphipod Ampelisca abdita. Environmental
Toxicology and Chemistry, 13: 1355-1365.
155
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o\
Figure 1.
SEASONAL VARIABILITY IN SURVIVAL OF
AMPELISCA ABDITA
EXPOSED TO CLEAN CONTROL SEDIMENT
(0
c
(0
0)
100-
90
80
i
1991
I I
1992
j
1
I
99
ii
3
I.
%
i
jjtm
y
\
\ i
\ \
\ \
199
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Figure 2.
SURVIVAL OF AMPELISCA ABDITA
EXPOSED TO SIX SEDIMENTS
100
g 80
E
'E
S>
O
60
40
20
f
•
LEGEND
Jamaica Bay Animals
Rhode Island Animals
Sandy Hook Animals
•"•©••••
B C D E
Sediment Exposure
*<•>
-------
00
100
80
60
CO 40
20
Figure 3.
SURVIVAL OF AMPELISCA ABDITA
EXPOSED TO FOUR SEDIMENTS
LEGEND
Rhode Island Animals
Sandy HocfcAnimals
B C
SEDIMENT EXPOSURE
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Figure 4.
SENSITIVITY OF THREE
AMPELISCA /ISD/WOPULATIONS
1.5
9
O
1.0
8 0.5
O
0.0
Narrows River SanFrancisco Bay Sandy Hook Bay
Rhode Island California New Jersey
POPULATION OF ANIMALS TESTED
Lines above bars represent two standard deviations.
Line below graph indicate significant difference between populations.
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MARINE BORER CONTROL:
PREPENETRATION STRATEGIES AND POSTPENETRATION OPTIONS
Karim A. Abood and Susan G. Metzger
Lawler, Matusky & Skelly Engineers
Pearl River, NY 10965
Two groups of marine invertebrates destroy wooden structures in the saline environments
of Upper New York Harbor: molluscs of the family Teredinidae (commonly referred to as
Teredos, or shipworms) and crustaceans of the order Isopoda (genus Limnoria, commonly called
gribbles) (Figure 1). These organisms have been responsible for millions of dollars of damage
annually to waterfront structures.
Teredinids are highly specialized bivalve mollusks. Larval forms resemble the small larvae
Of other marine bivalves, such as clams, but the adult form is adapted for living in tunnels bored
into wood. Adults have a wormlike body, hence the common name, shipworm. The valves, or
shells, of teredinids are small with finely sculptured teeth. A muscular foot can press the valves
against the anterior end of the burrow. By alternating contractions of anterior and posterior
adductor muscles located along the body, shipworms can manipulate the valves so as to rasp off
wood particles and develop the characteristic teredinid tunnel. Teredos can destroy unprotected
piles in as little as nine months by burrowing into the wood to create internal tunnels that are
virtually undetectable from the surface. The worms spend their adult lives in the protected habitat
of the tunnels, but must retain their association to the marine environment by extending their
siphons out of the tunnels. Oxygen and food are drawn into the tunnel; excretory and
reproductive products are released into the water body.
These tunnels weaken the structural integrity of pilings. The extent of damage caused by
Teredo infestation is difficult to estimate or measure because there are no easily observed external
symptoms until damage is severe and significant structural losses have occurred. Damage varies
from pile to pile within a pier and within individual piles. Infestation tends to be heavier in the
lower portions of piles (near the mud line) as compared to upper portions. Interior deterioration,
including that caused by Teredo spp., cannot be detected by visual observations. Two methods
are generally used to detect internal deterioration: (1) nondestructive testing (NDT) methods
using some transmitted and received signals such as ultrasound and (2) destructive sampling using
a core that removes a portion of the pile for laboratory evaluation. Typically, inspections of pile-
supported structures are conducted using a comprehensive program of two or three levels of
detail.
Damage caused by Limnoria is usually quite visible on timber piles and is characterized by
an hourglass shape between the mud line and the mean high water line. Section loss can be
assessed by comparing circumference or diameter measurements of the thickest or original pile
diameter (if known) and thinnest portion of the pile. Pockets of denser wood or knots often may
be left untouched by Limnoria, thus, these appear as branches or spikes on the pile surface and
indicate the extent of the original pile diameter. Often, piles that have been extensively attacked
by Limnoria retain their original pile diameter and surface above the mudline or immediately
above the high water line.
Limnoria, or gribbles, destroy wood at a slower rate than shipworms. Two species of
Limnoria, L. lignorum and L. tripunctata, infest New York Harbor. Like Teredo, Limnoria tends
to move with the wood grain; however, Limnoria is a small species only a few millimeters in
length, and thus this species must maintain contact with the surrounding seawater by drilling
respiratory pits from its burrow to the outside environment. This limits the animal's ability to
move deep into the wood and results in a surface honeycombing that is easily broken away.
Limnoria consumes the wood as it burrows; the burrow itself is not needed as a habitat because
the animal's body is covered by a protective exoskeleton and can be tightly attached to the surface
of wood by its peraeopods. These species damage wood from the surface by burrowing about 6
mm deep and then tunneling below the surface of the wood, creating honeycomb-like structures.
The weakened surface erodes with wave action, resulting in a gradual reduction in pile diameter
and exposure of new wood for attack.
160
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Strategies to control these borers must take into account their effectiveness, initial and
long-term maintenance costs, and environmental impacts. Existing strategies fall into two
categories: prepenetration exclusion techniques that prevent infestation and postpenetration
techniques that kill organisms that have settled before they cause structural damage (Figure 3).
Some control strategies function both ways: they prevent new penetration and kill existing
infestations, often by placing a barrier around the wood that prevents the exchange of oxygenated
water thus smoothing the organisms. Use of silicon grease, for example, smothers Teredos living
inside the wood and prevents new larvae from attaching themselves to the wood.
The most cost-effective prepenetration techniques usually rely on some aspect of the
reproductive biology of these organisms or some component of their life-cycle requirements to
protect waterfront structures from infestation and to establish long-term maintenance programs.
For example, fertilized shipworm eggs develop into free-swimming larvae that remain in the water
for a few weeks and may settle on wooden structures and eventually penetrate them. Keeping the
larvae off the wood during the 6-8 week period of larval presence is the basis for cost-effective
prepenetration exclusion strategies. This may be accomplished by behavioral avoidance or
physical exclusion techniques listed in Figure 3.
The selection of appropriate postpenetration remediation technologies is also biologically
driven. Knowledge of essential organism requirements (e.g., oxygen, salinity, temperature
preferences, and species-specific differences in response) can form and has been the basis for
many of the treatment technologies presented in Figure 3. Most of the methods provide a hostile
environment inside the tunnels created by these organisms and attempt to preserve the remaining
cross sections of the structural elements.
The principal commercially available chemical preservatives used to pressure-treat wood
products can be grouped into three categories: creosote and creosote-coal tar solutions, oilbome
preservatives, and waterborne arsenicals. In principle, injecting wood with chemical preservatives
makes the wood cellulose, or food substance, toxic and renders it useless as a food source to
biological organisms. As a remediation technique, chemically treated wood is generally limited to
full or partial replacement of damaged structures.
Several waterborne preservatives (i.e., toxic metallic salts dissolved in water) are acceptable
for use in the marine environment, including ammoniacal copper arsenate (ACA), ammoniacal
copper zinc arsenate (ACZA), and chromated copper arsenate (CCA). The waterborne arsenical
compounds are applied as an aqueous solution to the wood; as the water evaporates, the chemical
is left behind to the wood's cellulose which prevents leaching or loss of such compounds upon
subsequent wetting or exposure to water. Generally, CCA is used with southern pine, and ACZA
or ACA is used with Douglas Fir. Both CCA and ACA can be used either above or below the
waterline. Either one in combination with creosote (dual treatment) is more effective in
preventing marine borer damage than any single treatment. (Note: Although dual treatment with
CCA or ACA and creosote imparts the greatest level of protection against a broad spectrum of
marine boring organisms, it is also the most expensive type of treatment.)
The initial use of polyvinyl chloride (PVC) and/or polyethylene (PE) film as a protective
coating for underwater structures was for in situ pile wrapping as a means of mitigating existing
wood structure degradation. Pile wrapping has been determined to be a very effective,
economical, and long-lasting technique for protecting wooden structures from biological
degradation. In order to reduce the cost of wrapping in situ, new piling (treated or untreated) to
be used for complete or partial replacement can be wrapped prior to driving or posting. Two
landside application methods have been used by the Port of Los Angeles and elsewhere: (1)
wrapping the pile in a way similar to that in which divers apply the wrap underwater and (2) heat-
shrinking a 0.02-inch-thick PE film onto the pile. For both methods, cutting the pile to the right
length and making all forming cuts and holes prior to applying the wrap maintains the
effectiveness of the barrier.
Environmental modifying techniques are techniques that alter the physical environment to
make it unusable or take advantage of natural behavior patterns to attract or repel aquatic
organisms. In general, the devices rely on the response of aquatic organisms to an artificial
stimulus and are therefore subject to performance variations among species, developmental stage,
and age.
161
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Figure 2 lists several potential environmental modifying techniques that may be effective at
limiting wood borer access to underwater wooden structures; however, there is insufficient
information available to indicate that any have been tested.
A variety of prevention technologies have been suggested to address Teredo and Limnoria
infestations (Figure 3-1). However, the methods proposed work equally well for Limnoria.
Many factors must be considered in developing a cost-effective remedial approach and
implementation strategy. These considerations include the level and distribution of existing
Teredo infestations, the level of section loss and related losses in structural capacity, the
likelihood that additional or new infestations will occur, the remaining life span of facility piles,
and the near-term and long-term cost-effectiveness of applicable prevention and remediation
technologies.
162
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Figure 1
• Peraeon
(thorax, 7 somites)
Pleon
abdomen, 6 somites
Antennae
Brood pouch | 5th Peraeopod (Pleopods
with eggs
Gribble (Limnoria)
Source: Adapted from R.J. Mercies (1955)
(Not show at same scale)
Incurrent siphon
Excurrent siphon
Source: Adapted from R.O. Turner (1966)
Shipworm (Teredo)
163
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Figure 2
Piling and Wooden Structure Biodegradation Prevention
Technologies Classification
PREVENTION TECHNOLOGIES
_L
PREPENETRATION
EXCLUSION
Physical
Exclusion
1
Behavioral
Avoidance
• PVC Barrier
• PE Barrier
• Concrete Barrier
• Metallic Barrier
• Polyurethane
Coating
• Plastic Wrap
• Antifouling Paint
• Marine Accretion
• Dual Cover
• See Chemical
Treatment
1
• Water Jets
• Air Bubblers
• Electrical Barrier
• Magnetic Barrier
• Sound
• Light
• Turbidity Shield
• Low-Salinity Shield
• Habitat Modification
• Biological Control
• Adjacent Habitat
POSTPENETRATION
TECHNIQUES
_L
Barrier
Systems
1
Chemical
Treatment
1
•See
Physical Exclusion
Methods
• Dual-Barrier
and
Treatment Methods
i
Waterborne
Preservatives
Polymers
Fumigants
Tygard Capsules
Antlfoullng Paints
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THE EFFECTS OF DREDGED MATERIAL DISPOSAL ON WATER QUALITY
IN THE POOLES ISLAND REGION OF CHESAPEAKE BAY
Bruce D Michael and William D. Romano
Maryland Department of the Environment
Baltimore, MD 21224
The Pooles Island region of Chesapeake Bay is used to accommodate dredged material for
the maintenance of the Chesapeake and Delaware (C and D) Canal Approach Channel, Brewerton
Extension and other approach channels to Baltimore Harbor (Figure 1).
In the fall of 1989, Maryland Environmental Services contracted MDE to conduct a water
quality analysis on the Effects of Dredged Material Disposal on Water Quality in the Pooles Island
Region of Chesapeake Bay. Disposal consisted of two different projects, one from the C and D
Canal Approach Channel and the other from the Brewerton Extension Approach Channel.
The method of dredge disposal for both projects was the bottom-dump method where
material from the dredge site is loaded onto a scow and transported to the disposal site where
material is released from the bottom of the transport vessel.
The major objectives of the water quality monitoring program were to provide basic
characterization of water quality in the disposal area; characterize and evaluate effects, if any, of
depositing dredged sediment in designated areas; and provide information for future assessments
of the dredge disposal area The information from this project is presently being used to help
evaluate the water quality effects from hydraulic dredge disposal in the G-West area off Pooles
Island.
Concerns over disposal of dredged sediments in Chesapeake Bay revolve around the
possible degradation of water quality and the effects on increased turbidity, release of nutrients,
excessive algae blooms, benthic communities, SAV habitat and fish habitat.
The Pooles Island water quality monitoring project consisted of two "before, during and
after" studies for each disposal project which made a total of twelve monitoring cruises. The first
study characterized impacts from the disposal of 1,091,722 cubic yards of sediment from the C
and D Approach Channel and the second study characterized the impacts from the disposal of
273,436 cubic yards of sediment from the Brewerton Extension channel. Both projects deposited
material in close proximity to each other south-west of Pooles Island.
The sampling design was developed to take advantage of the comprehensive Chesapeake
Bay Water Quality monitoring program conducted by MDE since June of 1984. This program
establishes the regional water quality status and trends throughout the Chesapeake Bay mainstem
and tidal tributaries and involves twenty sampling cruises per year.
Eight sampling stations were added to supplement the three existing mainstem water quality
monitoring stations in the Pooles Island area (Figure 2). These were added to characterize die
area and provide the spatial coverage needed to detect any major water quality impacts of
sediment disposal in the study area. The mainstem station MCB3.1, or station #1, was always
sampled in conjunction with the eight new Pooles Island stations. For each "before, during and
after" study, all nine stations were monitored for the same suite of physical and chemical
parameters as measured in the Chesapeake Bay mainstem program. For the four "during"
disposal cruises, five additional stations were sampled at the immediate disposal site.
The Pooles Island region is characterized as a turbidity maximum zone and the water
quality is strongly influenced by mixing of fresh water flowing down the Bay from the
Susquehanna River and saline waters circulating up from the mouth of the Bay. The area around
Pooles Island is relatively shallow — usually less than 7 m. except in the channel where depths are
approximately 13.5m.
A general water quality characterization of the Pooles Island region of Chesapeake Bay for
the time period between September 7, 1989 and September 24, 1990 consisting of twelve cruises
was conducted using all disposal and non-disposal cruise data from the nine stations forming a
grid around the designated disposal areas in G-North and G-South. The parameters analyzed
were TN, DIN, TP, DIP, NH4, TSS, active chlorophyll and Secchi depth (Figure 3-6). There
were no significant differences in most concentrations from the regional non-disposal to disposal
cruises. There does appear to be somewhat higher concentrations of NH4 during disposal cruises
165
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in the region, but due to the variability of NH4 in this region, a more in-depth study of NH4
sources and sinks from the sediments and other external sources was recommended.
Water quality from the four "during" disposal cruises was compared with station #7, which
is also the Chesapeake Bay mainstem station which was sampled twenty times during the year.
This comparison was done to determine which parameters exhibit a near-field, short term-impact
from the disposal of dredged sediment. For the "during" cruises, the disposal site was
characterized by five stations collected within close proximity to the disposal site. The proximate
stations were selected to cover the four quadrants surrounding the dredged sediment disposal site.
The first station collected was directly over the dump site. The next two stations were always
within the visible plume. The last two stations monitored were just outside the plume. It is
clearly evident that surface values for TP and TSS at the proximate stations for the four "during"
cruise were elevated in comparison with station #7 and that Secchi depths were slightly lower for
3 out of 4 "during" cruises (Figure 7-10). These elevated values were not apparent in the regional
assessments and indicate a near-field and short-term impact on water quality.
To further examine the near-field, short-term impact to water quality in the plume, the
proximate stations were subdivided and compared. The two proximate stations monitored in the
quadrants containing the plume were grouped together and the two stations monitored in the
quadrants outside the plume were grouped together.
All parameters were analyzed for both surface and bottom samples separately, comparing
plume and non-plume stations using the nonparametric Wilcoxon 2-sample statistical test for
determining any significant differences. The only parameters that showed a significant difference
between plume and non-plume stations in the surface and bottom samples were TSS and TP. In
parameters TN and NH4, there was a large difference only in the bottom samples (Figure 11).
The additional differences in bottom samples could be the result of the rapid settlement of the
plume to the bottom where TSS, TP, TN and NH4 could remain high for longer periods of time
than at the surface.
Conclusion from the bottom-dump dredge disposal water quality monitoring project in the
Pooles Island region of Chesapeake Bay indicated several short-term, near-field water quality
impacts, but no regional, large-scale or long-term impacts. Most variations in water quality
parameters can be attributed to natural background variability due to the proximity of the study
area to the turbidity maximum zone and discharges from the Susquehanna River.
MDE is currently conducting a water quality monitoring program to address the effects of
hydraulic dredge disposal in the Pooles Island region. This area, know as G-West, is significant
because of a sediment "berm" that was constructed by the bottom-dump deposition of sediment to
make a confinement area to hold hydraulic dredged sediment from the C and D canal. The berm
was constructed during the winter of 1994 and hydraulic dredge material was first placed in G-
West behind the berm during November and December, 1994.
REFERENCES
Haire, M.S., R.E. Magnien, B.D. Michael, 1988. Work/Quality Assurance Project Plan for
the Maryland Department of the Environment Chesapeake Bay Water Quality
Monitoring Program — Chemical and Physical Properties Component. 42 p. plus
Appendices.
Magnien, R.E., D.K. Austin, B.D. Michael, 1990. Maryland Department of the
Environment, Chesapeake Bay Water Quality Monitoring Program, Chemical/Physical
Properties Component Level I Data Report. 46 p. plus Appendices.
Panageotou, W. and J. Halka, 1988. Maryland Geological Survey Coastal and Estuarine
Geology Program, Monitoring of Sediments Dredged from the Approach Channel to the
Chesapeake and Delaware Canal: October 1986 - June 1987: Final Report. File Report
50. 124 p.
Panageotou, W., 1991 Maryland Geological Survey. Personal Communication.
166
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ON
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168
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Figure 11
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CONTROLLING NITROGEN INPUTS INTO THE PECONIC ESTUARY SYSTEM
Vito Minei and Walter Dawydiak
Suffolk County Department of Health Services
Office of Ecology
Riverhead County Center
Riverhead, N.Y. 11901
A surface water quality management effort for the Peconic Estuary, Long Island, N.Y., has
relied on nitrogen control for separate mitigation and preservation issues. The management
effort's focus has been on attainment of the dissolved oxygen standard for surface waters, but is
now being expanded to integrate other management concerns, such as submerged aquatic
vegetation.
Surface Water, Sediment, and Pollutant Loading Characterization
In the Brown Tide Comprehensive Assessment and Management Program (BTCAMP),
ambient surface water quality was characterized through an extensive, multi-year program of
monitoring of surface waters, sediments, tributaries, and point source discharges. The surface
water monitoring occurred over several years at numerous stations in the main bays system as
well as in tributaries and at point source discharges. The BTCAMP data was augmented with an
extensive historical monitoring database, which includes decades of monitoring data from the
Suffolk County Department of Health Services (SCDHS), extensive documentation from the
Long Island Comprehensive Waste Treatment Management Plan (L.I. 208 Study, 1978), and data
from Long Island University.
An assessment of pollutant loadings also was performed for all known potential point and
nonpoint sources. This assessment was accomplished by a combination of comprehensive land-
use analyses, engineering estimates of loadings, and direct measurements of groundwater quality
and point and nonpoint source discharge quality and quantity. Thousands of groundwater
samples from ongoing programs were used in the assessment.
The surface water and sediment quality data and pollutant loading information were utilized
in a state-of-the-art mathematical computer model of the Peconic estuary system ("WASPS," an
enhanced version of USEPA's "WASP4" model). This model is a system of coupled
hydrodynamic and water quality models which can be used to examine circulation, water quality,
and eutrophication. The model was used to evaluate various management alternatives. The
monitoring, modelling and assessment, as well as the recommended management alternatives, are
presented in the BTCAMP report, which contains numerous .
presentation-quality graphics and tables (e.g., monitoring locations, pollution source locations and
loading rates).
Nitrogen Guideline
A critical cornerstone in the management analysis was that nitrogen has been found to be
the limiting nutrient in the Peconic Estuary system. Through an analysis which related nitrogen
concentrations to chlorophyll-a concentrations and then compared chlorophyll-a levels to diurnal
dissolved oxygen (D.O.) fluctuations, a safe threshold level of nitrogen of 0.5 mg/1 was
established in Flanders Bay to prevent excessive dissolved oxygen depression. This level of
nitrogen is routinely exceeded in western Flanders Bay, where occasional, localized dissolved
oxygen depletions have occurred. However, the system generally has not demonstrated
characteristics of advanced eutrophication in terms of conventional nutrients and D.O. depletion.
This evidence suggests that the Flanders Bay system currently may be near the limits of the factors
of safety incorporated in the determination of the nitrogen guideline, indicating that the system
could experience serious eutrophication and water quality degradation problems if pollutant
loading were to increase. The water quality in Eastern main bays is excellent with respect to the
nitrogen guideline and dissolved oxygen.
178
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Management Issues
Despite the quantitatively high nitrogen loads of groundwater underflow, the most
significant of all of the controllable nitrogen loadings in terms of impact on the estuarine system
were found to be the Peconic River and the Riverhead Sewage Treatment Plant (STP) due to the
concentrated nature of the STP discharge at a location near the mouth of the Peconic River, a
poorly-flushed area of the Peconic Estuary system. Meetinghouse Creek, apparently suffering
from residual effects of historical duck farming, was found to have significant localized impacts
but only marginal system-wide impacts. Sediment nutrient flux rates, which are obviously
affected by the above inputs, were extremely high in the western bays system.
Peconic River/Flanders Bay Mitigation Approach
To prevent further surface water degradation, BTCAMP recommended several land use
controls in the Peconic River watershed (e.g., minimum two-acre zoning) as well as point source
discharge permit limitations to immediately restrict Peconic River-discharging sewage treatment
plants at existing levels. BTCAMP also recommended a long-range goal of upgrading the
Riverhead STP to ensure attainment of the recommended surface water quality nitrogen guideline.
BTCAMP has ripened into the Peconic Estuary Program (PEP), a three-year National
Estuary Program study. The BTCAMP "no net increase of nitrogen" point source
recommendations for the Peconic River have been adopted by the PEP Management Conference
and are being implemented. The PEP has also committed to evaluating and implementing
mechanisms to abate nitrogen pollution so that the nitrogen guideline may be attained.
In addition, the PEP is refining and expanding BTCAMP technical data, especially in the
eastern Peconics and in subwatersheds for peripheral creeks and embayments. The water quality
model link-node network will be refined, and improved sediment nutrient flux and predictive
dissolved oxygen submodels are being incorporated.
Preservation Policy
Numerous traditional and innovative mechanisms to protect water quality are being
explored, such as "discharge restriction categories" and new surface water classifications and
standards for "water quality preservation" in the eastern Peconics. A cooperative initiative with
local governments to scope out components of the water quality preservation is underway; this
includes a comprehensive "base programs analysis" to improve programs and institute best
management practices, where feasible.
Integration of Other Management Issues
A strong living resources component is also being incorporated into the PEP (e.g., linkage
of water quality to submerged aquatic vegetation). Already, this has had interesting implications.
For example, the finding that there are no major beds of eelgrass in the western or central portions
of the Peconic Estuary may have profound implications on nitrogen management in the estuary.
Previously, central main bays quality was considered excellent with respect to nitrogen in relation
to attainment of the dissolved oxygen standard. However, nitrogen may adversely affect eelgrass
due to light shading from excessive algal blooms or by direct metabolic impacts. The PEP will
continue its eelgrass management program, possibly linking it with the water quality model. The
modelling consultant is pursuing incorporation of a benthic macroalgae submodel, as well as a
light extinction model.
• The PEP toxics characterization, which included sediment profile imaging (i.e.,
photography of sediment profiles to assess benthic community, organic deposition, etc.), is also
underway. The draft report indicates that toxics are not a significant problem in Peconic Estuary
sediments However, sediment stresses in certain areas were noted due to conventional
depositional problems (i.e., organic carbon and associated nutrients). The information in the
toxics report, in conjunction with other tasks (e.g., submerged aquatic vegetation, sediment
nutrient flux, surface water modeling), may provide compelling support to the development of
management strategies for water and sediment quality preservation and nutrient management,
especially in the central main bays system.
179
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COMMUNITY-BASED EDUCATIONAL OUTREACH TO AT-RISK URBAN
ANGLERS
Kerry Kirk Pflugh, Research Scientist
Judith Auer Shaw, Research Scientist
Elizabeth Yacovelli, Research Assistant
Leighann Von Hagen, Research Assistant
Division of Science and Research
New Jersey Department of Environmental Protection
CN409
Trenton, NJ 08625
ABSTRACT
In 1982, research conducted by the New Jersey Department of Environmental Protection (NJDEP) showed elevated
levels of chemical contaminants in six species offish and crabs in the Newark Bay Complex. Subsequently, advisories
were adopted by the State of New Jersey to guide citizens on safe consumption practices. Traditionally, advisories have
been issued primarily through the media complemented by brochures and flyers. As issues of environmental justice are
raised, the State has become increasingly aware of the need to conduct more innovative education programs that will reach
culturally diverse, economically depressed and non-English speaking populations.
This paper will describe the grassroots community-based education effort conducted in the Newark Bay Complex
to reach at-risk urban anglers with fish consumption advisory information. The effort was targeted primarily at: (1)
communities, who may be non-English-speaking, of low economic status, and whose cultural traditions may include
consumption of species identified as contaminated; (2) urban anglers who may not be affiliated with professional and
recreational organizations and whose primary source of protein may be contaminated fish; and (3) school age children
interested in understanding the relationship between pollution, fish consumption and public health.
INTRODUCTION
When we hear the term environmental justice, we are accustomed to thinking about the
inequity of siting a waste facility or other undesirable pollution generating facility in communities
that are economically depressed, have existing environmental contamination and whose citizens
are politically disenfranchised, lacking the power and resources to put up a challenge. Another
aspect of environmental justice that also creates an inequity among people is the way government
communicates with citizens. Traditionally, agencies when wishing to communicate rely on press
releases, brochures and flyers and legal notices. These are generally written in English and
published in the English press. While this method reaches a vast audience, it fails to reach groups
that do not have access to government communication networks and who may be most in need of
the information.
This paper will describe an example of a government initiated communication effort
concerning a local environmental problem. The subject is notification of the public about fish
consumption advisories. The location is the Newark Bay Complex. The Complex includes the
Newark Bay, tidal portions of the Hackensack and Passaic Rivers, the Arthur Kill and the Kill
Van Kull. The complex is a highly industrialized urban area consisting of a large racially and
culturally mixed population of more than 3 million people. It covers more that 30 local
governments and five counties.
In the state of New Jersey, with over 130 miles of coastline, fishing is a multi-billion dollar
commercial industry and a popular recreational sport. New Jersey is also home to many of the
largest chemical producers in the country, most of which are located near the most accessible
transportation routes of travel — the bays and estuaries of the coast. With its successful industries
creating many jobs and its convenient location, New Jersey also attracted a population of over
seven million people, most of who are concentrated in the heavily industrialized northeast (Shaw,
1994).
So what happens when industry and a concentrated population meet a coastal ecosystem?
Increased likelihood of legal discharges, improper disposal, accidental spills, the crossing of
contaminants from the environment into local fish populations and increased risks to recreational
seafood consumers. All of this played out in classic fashion in Newark Bay Complex in the years
before 1976 (Shaw, 1994).
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In 1977, EPA moved to ban the manufacture of PCBs, a probable carcinogen known to
produce toxic effects in the laboratory at very low doses. Due, most likely, to a discharge of well
over 500,000 pounds of PCBs from a facility on the Hudson River (Barclay, 1993), these
substances along with dioxins and others passed through the aquatic environment of the Newark
Bay Complex continue to enter the food chain of crustaceans and finfish and build up in the Bay
sediments (Shaw, 1994).
In 1982, research conducted the NJDEP in the Newark Bay Complex showed elevated
levels of chemical contaminants in certain fish and crabs (Belton et. al., 1982). Subsequently,
advisories were adopted by the state to guide citizens on safe consumption practices.
The species under advisory include bluefish, blue crab, American eel, white perch, striped
bass and white catfish. Advisories range from "do not eat" to "eat no more than once a week or
once a month" depending on whether you are considered a high risk individual or general
population. A high risk individual is defined as a woman of child bearing age, pregnant and
nursing women, and infants and children up to 15 years of age. The primary health affects of
concern are reproductive disturbances, developmental problems and an increased chance of
developing cancer if consumed over a lifetime.
The advisories were issued through several means at the time ~ the Fish and Game Digest,
a publication distributed to licensed anglers and bait and tackle shops throughout the state, and
signs posted in areas of concern. Since then advisories have been issued annually in the Digest
and through the Department of Health.
While this approach had been successful in reaching recreational anglers who purchase
fishing licenses, it was not effective in reaching urban recreational anglers in the Newark Bay
Complex because a recreational fishing license is not required in marine waterways.
Fishing organizations and environmental groups concerned that urban recreational anglers
and subsistence anglers were not receiving vital health information about consumption of
contaminated fish and crabs approached the NJDEP and asked that a special outreach effort be
initiated in the Complex.
New Jersey responded by applying for and receiving a grant to design a community-based
outreach program to urban anglers and citizens. This approach — working with citizens within a
community ~ establishes a contact for the state at the local level and in turn a contact for local
leaders at the state.
The project began appropriately with identification of community leaders and an assessment
of their knowledge and concerns about fish consumption advisories. This initial contact took the
form of a phone interview with selected citizens. These people included local and county health
officers, conservation officers and marine police, environmental and fishing group members and
civic leaders. The phone interview sought to learn their knowledge offish consumption
advisories, knowledge of health affects associated with consumption of contaminated fish and
concern about fish consumption advisories in general. It also sought to learn how information is
shared in the various communities within the Complex.
Overall, we learned that while there was a vague awareness of advisories, it was not an
important health issue to health officers and they were not routinely issuing advisory information
to their constituents. In fact, some health officers were unconvinced of the necessity of
advisories. Sportsmen groups indicated that they had a vague awareness of the advisories and
while some were complying most recreational anglers either did not know about the advisories or
did not believe there was a problem with the fish and crabs. In addition, we learned that where
advisories could be enforced, enforcement activities were not taking place. In short, the
advisories in the Newark Bay Complex were virtually unknown or for the most part were being
ignored. It was cleat what our goals needed to be:
1. To inform urban anglers oFthe fish consumption advisories and bans,
2. To explain the health risks associated with consumption of contaminated species,
3. To reduce exposure to potential health risks,
4. To establish mechanisms to disseminate future information quickly and effectively to
urban anglers, local environmental mangers, and health care providers,
5. To establish programs to encourage catch and release, and
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6. To establish a volunteer network of people to assist with information distribution to
urban anglers annually.
From January through March of 1994, meetings were held at three sites within the complex.
Local and county health officials, environmental and fishing group representatives, and interested
local leaders attended these meetings. These early meetings focused on sharing scientific
information about the advisories with the representatives and learning how each group wished to
design an outreach effort. All sites agreed that brochures and signs were needed immediately,
followed by public information meetings in affected communities.
These materials were developed and throughout the summer of 1994 information materials
were handed out at different local events within the complex as well as through local youth and
recreational organizations. In December of 1994, a mid-term evaluation was conducted with local
contacts to learn how the information program had worked and to plan for future needs and
directions.
The evaluation indicated that while many urban anglers had become aware of the
advisories, there was still a great deal of recreational consumption taking place. Several other
observation were revealed:
1. more signs are needed around the complex,
2. more non-English brochures are needed,
3. greater use of the non-English media are needed,
4. additional sports groups should be contacted,
5. advisories should be posted in bait and tackle shops,
6. participation at local events should increase,
7. enforcement activities should increase,
8. local customs, disbelief of health information and the abundance of healthy looking
crabs inhibit adherence to the advisories, and
9. more volunteers are needed to hand out brochures at known fishing sites.
These results point to a need to initiate a more targeted public information campaign that is
tailored to: 1) non-English speaking communities whose cultural traditions may include
consumption of these contaminated species; 2) people of low economic status and subsistence
anglers who may not be affiliated with professional and recreational organizations and whose
primary source of protein may be contaminated fish; and 3) school-age children in the Newark
Bay Complex who might benefit from an environmental education curriculum that includes an
explanation of the relationship between pollution, fish consumption and health.
Thus, this year site teams have focussed on development of: lesson plans for schools on the
history of the Complex focussing on human impacts to the estuary, the fishery and ultimately
human health; public service announcements on the advisories in three languages; and an anglers
survey to learn the consumption patterns of urban anglers, how they get their information about
fish and fishing and who they trust to deliver that information.
Ultimately, the goal of this project is to educate citizens so that they have choices and that
the choices they make are informed choices which will protect their health. With encouragement
from community leaders combined with a public information program that offers alternatives,
citizens will have the power to reduce their exposure to contaminants and protect their health.
Through the education efforts of this project, citizens can effect changes in local consumption
patterns and behavior by knowing alternatives to consumption of unsafe fish and crabs, by
learning of safer locations to fish and crab, and by learning how to properly prepare those fish
they can consume in limited quantities.
In conclusion, it is not enough for agencies to release health advisories to the public
through traditional channels such as the press and expect the public to change behavior. If
government is truly concerned about protecting public health, it must reach beyond the traditional
means of communication and design programs that recognize the unique features of a local
community. This can only be done by being interested in the citizens themselves ~ by learning
who the affected citizens are, by listening and responding to citizen concerns and by offering real
alternatives to those citizens who may be negatively impacted in some way by government action.
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While this approach may take more time up-front, ultimately a more balanced and equal public
notification program is achieved. This is the only just way in which to communicate, particularly
to those communities disconnected from the traditional information channels used by government.
REFERENCES
Barclay, Bridget, 1993. Hudson River Angler Survey, Hudson River Sloop Clearwater, Inc.
Poughkeepsie, New York
Belton, T.J., Ruppel, B.E. and Lockwood, K., 1982, PCB's (Anocher 1254) in Fish Tissues
Throughout the State of New Jersey: A Comprehensive Survey, Trenton: NJ
Department of Environmental Protection, Office of Cancer and Toxic Substance
Research, p. 36
Christini, Angela, 1993. Polychlorinated Biphenyls (PCBs), Chlordane and DDTs in Selected
Fish and Shellfish from New Jersey Waters, 1988-1991. Division of Science and
Research. NJDEP, Trenton, NJ
Hauge, Paul, 1993. Polychlorinated Biphenyls (PCBs), Chlordane and DDTs in Selected Fish
and Shellfish from New Jersey Waters, 1988-1991. Division of Science and Research,
Trenton, NJ
NJDEP, 1994. "A Guide to Health Advisories for Eating Fish and Crabs in New Jersey,"
NJDEP, Division of Science and Research, Trenton, NJ
Pflugh, Kerry Kirk, J.A. Shaw, and B.B. Johnson, 1992, "Establishing Dialogues with
Communities: A Guide to Effective Communication Planning, Division of Science and
Research, NJDEP
Shaw, Judith Auer, Risk Management Teams: State and Local Cooperation to Protect Public
Health in Urban Coastal Communities, presented to ATSDR Conference, September,
1994, Atlanta, Ga.
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REVIEW OF HISTORICAL TIDAL WETLANDS OF THE DELAWARE RIVER
ESTUARY
Kurt Philipp, Vice President
Wetlands Research Associates, Inc.
102 East Main Street
Newark DE, 19711-7319
Historical Tidal Wetlands of the Delaware River and Bay have been characterized for the
Delaware River Estuary Program. The characterization focused on the alteration mechanisms of:
Impoundments (waterfowl, agriculture, and stormwater); Filling (for
urban/Cpmmercial/Residential Development and Dredge Material); Hydrological Alterations
(road/rail/dredge material restrictions); Mosquito Control; Sea Level Rise (coastal inundation);
Inlet Formation and Stabilization (and storm event changes); Phragmites Distribution; and Snow
Goose Grazing. The study was conducted through investigation of case study areas selected
throughout the estuary that represented examples of these alteration mechanisms.
The most pervasive of these impacts was the impoundment of tidal marshes and adjacent
non-tidal wetland edge. Impoundments or meadows were created on nearly all freshwater, most
brackish water, and some salt water marshes. This corresponded with settlement/population
densities and impoundment uses. During the colonial periods, impoundments were created in and
near towns and cities for roads across marshes and for flood control. With exception of higher
salinity areas, diked marshes provided prime agricultural land from the days of early settlement
into the 20th century. The landscape of coastal marshes today clearly displays the patterns of
these impoundments through modified drainage patterns, altered marsh vegetation, relic dikes,
and the pattern of shoreline land use.
Meadows began with early settlement affecting marshes from Trenton to Artificial Island
and extending further up major creeks along the New Jersey shore to Dennis Creek. Over this
distributional range, meadows replaced natural communities varying from freshwater tidal marsh
to salt hay marshes. Freshwater marshes were the most affected or lost because of their higher
value when converted to agriculture. Salt hay areas were diked for ease of water management
and harvest of the salt hay. Generally, failure of salt hay meadows resulted in establishment of the
lower Spartina alterniflora marsh.
Diking of tidal marshes influenced their subsequent land use and character. Diking often
resulted in relative subsidence of the land due to soil compaction within the meadow and relative
sea level rise in the estuary. When meadows were abandoned or dikes failed, the return of tidal
flow resulted in establishment of open water, tidal flats, or low marsh dominated by Spartina
alterniflora. Additionally, this timing of meadow failure may have influenced the susceptibility of
the restored marsh to the invasion of Phragmites.
Case study area reviews of historic tidal wetlands have shown the widespread impact of
impoundments and the role of these impoundment meadows as related to large scale filling of
historic wetland areas for made land.
Large scale filling for development in tidal marshes has been mainly associated with the
need for dredged material disposal sites. The largest fill projects have been direct disposal areas
for dredging: south Philadelphia, Tinicum Island, Killcohook, and Artificial Island. Former
impoundment meadows were convenient areas for dredged material disposal which later provided
land for development. Near urban areas, dredging of the Delaware River channel and filling of
meadows provided firm land for expansion of river related industries. Filling of riverine shallows
with dredged material in these urban areas extended the waterfront riverward and also provided
more usable land.
Consequently, tidal wetland impact of this type occurred near the
Philadelphia-Camden-Tinicum Island region, near Wilmington and the industrial area of Red Lion
Creek. The Philadelphia wetlands lost were tidal and non-tidal freshwater marsh.
Urban dredge and fill mostly affected meadows and was conducted in the late 1800s. The
filling of Tinicum Island meadows occurred later in the 1930s and 1940s. Dredged material
disposal unrelated to made land use has always been required in some areas, but greatly increased
around 1900 and again during the 1940s and 1950s. The large disposal areas of
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Woodbury-Mantua, Raccoon, Oldmans, Killcohook, and Artificial Island were created at this
time. These appear to have affected mostly meadow land. The Killcohook disposal affected
meadow, tidal marsh and uplands, but mostly riverine shallows. Artificial Island was
predominantly riverine shallows and resulted in a net increase in tidal marsh, although much of the.
original adjacent marsh was taken over by Phragmites.
Tidal wetland filling impact from highway projects occurred in the urban areas of Camden,
Philadelphia, and Wilmington during the 1960s and 1970s. Wetlands lost to this impact were
freshwater tidal marshes, and most recently, failed meadows. In some cases, entire small tidal
marsh/meadow systems have been filled for upland use, such as Hollanders Creek (South
Philadelphia), Mingo and Hook creeks (Tinicum), and Magazine Ditch (Wilmington).
Filling of historic tidal wetlands among case study areas was most associated with urban
development or dredged material disposal areas. Freshwater and brackish marshes were most
affected due to the location of urban areas in the study area.
Estimates of the rate of relative sea level rise are on the order of 1.5 feet over the 150 years
(3.0 mm per year) of map data investigated. The review of available aerial photographs of case
study areas beginning in 1927 to 1930 supports a general observation of shifts in marsh vegetation
community type from either high to low marsh in freshwater marshes or from salt hay to
cordgrass in salt marshes. This observation generally corresponds with the estimated rate (0.6
feet since 1930) of relative sea level rise and the elevation of tidal marsh communities.
Observations of a landward migration of tidal marsh community types in some case study areas
also supports this interpretation.
The impoundment of marshes over a period of significant sea level rise and an associated
subsidence/compaction of sediments within the impoundment creates a difference in restored
marsh surface elevation upon impoundment failure. Impoundment failure leads to the
establishment of a lower tidal wetland community, either a lower marsh or open water/tidal flats.
The general observation of the effects of relative sea level rise on tidal marsh vegetation in
the estuary confounds the interpretation of the effects of other alteration mechanisms. Variation
in the localized effects of relative sea level rise should be considered in the investigation of these
mechanisms, particularly the effects of mosquito control techniques, inlet formation/stability,
snow geese grazing and the restoration of meadows to tidal flow.
The search, identification, and review of case study areas has indicated the difficulty in
finding tidal marshes in the Delaware River estuary that have not been directly affected by human
activities. The majority of fresh and brackish water marshes and many salt marshes have been
impounded for human kind's use. The most pervasive human-related mechanisms of marsh
alteration are indicated to be impoundments, dredge and fill, and mosquito control. Next to
human-made impoundments, the effects of relative sea level rise are the most widespread as
indicated from the review of case study areas.
Changes in the aerial dominance of tidal marsh vegetation communities were observed
among the case study areas involving mosquito control techniques. However, no general trends
were suggested beyond the observation of an overall shift from salt hay to cordgrass, as described
in regarding relative sea level rise.
At the Fortescue study area, salt hay areas remained salt hay following the initial grid
ditching, then shifted to cordgrass after ditch cleaning and Open Marsh Water Management
(OMWM) ditching. Undisturbed salt hay areas shifted to cordgrass, but reverted back to salt hay
following OMWM implementation in one area. In the Dividing Creek area, all areas shifted from
salt hay to cordgrass, regardless of grid ditching, OMWM or no disturbance. In the Port Mahon
area, grid ditched areas of pure salt hay became even mixtures of salt hay and cordgrass that
either remained stable to the present or reverted back to salt hay. Undisturbed mixed marsh areas
also remain stable over this period.
All case study areas included the occurrence of Phragmites australis. The earliest aerial
photographs do not indicate Phragmites, except in possibly a few scattered occurrences.
Phragmites occurrence on the two large dredged material sites of Killcohook and Artificial Island
in from 1928 through 1930 is difficult to determine due to disturbance on these sites. Clear
indication of Phragmites infestations became evident in early 1950s photography. Many of these
areas are now dominated by Phragmites.
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The pattern of Phragmites invasion has been described regarding its association with large
dredged material disposal projects, failed meadows, and undisturbed marshes. The association of
Phragmites with land surface disturbance, including dredging, is well recognized. The association
to meadow dike failure seems apparent and is supported by the correlation of dike failure date and
the historic spread of the species. Although a pattern of spread within an undisturbed tidal marsh
has been described, the factors influencing such infestation are not apparent. There has been a
pervasive increase of both local small populations on upland disturbance sites and large dredge
material disposal sites. These sites contribute a dispersal pressure of seed and rhizomes to all tidal
waters that alone might account for the invasion into undisturbed marshes. Combined with the
factors of storm, sea level rise, or human-induced changes in hydrologic regime, such dispersal
pressures are more effective.
The effect of intensive snow geese grazing on Spartina alterniflora, cordgrass marshes in
Delaware has been well documented. Conversions of cordgrass to open water (eat outs) are
apparent in the case study areas. In Bombay Hook National Wildlife Refuge some former
cordgrass areas remain open water today while others have regenerated to cordgrass or salt hay.
In the Dennis Creek area, changes in the prevalence of cordgrass, salt hay and open water/tidal
flats varied in the 1928-1930 photographs to the present. Generally, conversion of cordgrass to
open water/tidal flats in this area, presumably attributable to snow geese grazing, reverted over
time to cordgrass again.
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LOCAL GOVERNMENT ROLE IN SHORELINE MANGEMENT
Jeryl G. Rose, Todd A. Grissom, and John M. Carlock
Hampton Roads Planning District Commission (HRPDC)
Chesapeake, Virginia
Donna E. Cesan
Chesapeake Bay Local Assistance Department (CBLAD)
Richmond, Virginia
Overview of Virginia's Chesapeake Bay Preservation Act Program
The Chesapeake Bay and its tributaries comprise one of the most productive estuarine
systems in the world, providing important economic and recreational benefits to the citizens of
Virginia. However, water quality and living resources in the Chesapeake Bay have declined
steadily over the last several decades, threatening the ecological and economic vitality of the
entire Bay region.
In 1988, the Virginia General Assembly enacted the Chesapeake Bay Preservation Act. The
Bay Act is a critical element of Virginia's multi-faceted response to the Chesapeake Bay
Agreement signed between the Bay states, the District of Columbia and the EPA in 1987. Central
to the Bay Act is the idea that land can be used and developed in ways that minimize impact on
water quality.
The Bay Act established a cooperative program between state and local government aimed
at reducing nonpoint source pollution by protecting environmentally sensitive land features from
inappropriate use and development. In doing so, a unique partnership was created between the
state and the counties, cities and towns of Tidewater Virginia. The Act recognized that local
governments have primary responsibility for land use decisions. The Act also expanded local
government authority to protect water quality and established a more specific relationship
between water quality protection and local land use decision-making. To implement the Act, each
locality must adopt a program based on the Preservation Area Designation and Management
Regulations adopted by the Chesapeake Bay Local Assistance Board in 1989 and amended in
1991.
Local Bay Act program compliance has three distinct phases. Phase I requires localities to
identify and map the extent of environmentally sensitive lands within their jurisdiction, to
designate them as Chesapeake Bay Preservation Areas, and to implement water quality
performance criteria in conjunction with the use and development of land within Preservation
Areas. Phase II requires local governments to adopt a comprehensive plan or plan amendment to
incorporate water quality protection measures consistent with the goals and objectives of the Bay
Act. The final phase, Phase III, requires localities to adopt or revise zoning, subdivision, erosion
and sediment control, plan of development and other land use management ordinances that
protect water quality consistent with the Bay Act. The remainder of this abstract focuses on
Phase II implementation which is currently underway in most localities in Tidewater Virginia.
Phase II of Local Bay Action Programs: Comprehensive Plans
The Chesapeake Bay's recreational, economic and social benefits create a quality of life that
has generated growth along its shores and those of its tributaries. Increased demand for public
recreational opportunities, such as swimming, fishing and boating, and waterfront residences each
with their own pier, can often conflict with the needs of the commercial fishing industry that is
dependent upon good water quality and an adequate habitat for living resources. Some of the
most desirable land for residential development is immediately adjacent to tidal waters, often the
same waters that watermen rely on to harvest seafood. Stormwater runoff coming from cleared
and paved land and entering nursery or shellfish areas, however, can drastically alter the basic
characteristics of these areas that make them so productive. The development of urban
waterfronts has also resulted in a critical loss of docking facilities for watermen. As waterfront
land values escalate, it is increasingly difficult for water-dependent industries to find alternate
sites.
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Even as local governments respond to the particular problems of providing suitable boat
dockage for waterfront residential development and water-dependent industry, truly public access
to the Bay and its tributaries is increasingly difficult for those same governmental entities to
provide. Less than one percent of the Bay's 5,300 miles of shoreline is publicly owned. Access
now consists primarily of marinas and other private facilities. In addition, development practices
which subdivide a ribbon of waterfront land into residential lots continue to cut off access
opportunities for other residents of the community.
Without question, there are multiple needs for the water resources of the Bay and its
tributaries and many times those needs compete. The challenge for Tidewater local governments
is to produce balanced economic development strategies that reconcile such competing interests.
All too often, public policy has not reflected an understanding of the relationship between land use
and water use. Activities on the land invariably impact upon the utilization and quality of water
resources. But local governments have the ability through the comprehensive planning process to
balance competing land and water uses while protecting water quality and sensitive marine
resources.
The Bay Act and its implementing regulations mark the first time Virginia local
governments are required to explicitly address water quality protection through the
comprehensive planning process. More specifically, the Bay Act Regulations require local
governments to first "establish an information base from which to make policy choices about
future land use and development that will protect the quality of state waters." The Regulations
require local governments to establish, as a minimum, policy statements in their comprehensive
plans on the following range of issues critical to water quality protection: physical constraints to
development, including soil limitations, with discussion of soil suitability for septic use; protection
of potable water supply, including groundwater resources; relationship of land use to commercial
and recreational fisheries; appropriate density for docks and piers; public and private access to
waterfront areas and affect on water quality; existing pollution sources; and, potential water
qulaity improvement through the revedevelopment of intensely developed areas. The regulations
also state that, "for each policy issue, the comprehensive plan should contain discussion on the
scope and importance of each issue, alternative policies considered, the policy(ies) adopted by the
local government, and a description of how the policy(ies) will be implemented." Finally, within
the policy discussion, the regulations state that "local governments should address consistency
between the plan and all adopted land use, public services, land use value taxation ordinances and
policies, and capital improvement plans and budgets."
Shoreline Element of the Comprehensive Plan: Developing Local Policies for Shoreline
Erosion Control and Public and Private Access Issues
Of the policy issues listed above which the Bay Act regulations require to be addressed in
the local comprehensive plan, several can be categorized into what is considered "the shoreline
element." This element focuses on shoreline management and how future development or
redevelopment of shoreline areas may affect water quality, particularly shoreline erosion control
and access. .
Shoreline ersosion control and public and private access to waterfront areas represent
important policy issues for local governments. A comprehensive approach to shoreline
management may also result in immediate cost savings to the community. Many coastal habitats
will change over time through natural forces irrespective of human land and water uses.
However, since human activities at or near the shoreline tend to increase erosion and,
consequently, degrade water quality, localities may reduce or even prevent the need for future
shoreline hardening by considering erosion during the local comprehensive planning process. The
shoreline protection efforts of individual property owners are often uncoordinated, unilateral
actions and, therefore, often fail to consider the effects on adjacent properties. In addition, all
shoreline erosion control structures will eventually fail and require replacement time and time
again. A comprehensive approach which guides future development would limit development in
areas not appropriate for any type of structural control or where certain shoreline hardening
measures would actually worsen erosion.
Past governmental and private efforts to control erosion along the region's shorelines have
mostly been directed at protecting and preserving resources on the landward side of the shoreline.
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The effects of erosion on the ecological and biological resources in the water bodies themselves
were generally considered to a lesser extent. For communities that rely upon commercial and
recreational fishing for their economic health, the need to understand these relationships and then
to put that understanding to work to protect identified or potential habitat for living resources is
obvious and crucial.
Marinas are located right at the water's edge, and often there is no buffering of pollutants
generated by boating activity or carried by runoff from parking lots and boat maintenance areas.
Dissolved oxygen deficiencies and high concentrations of toxic metals in aquatic organisms have
been documented in the vicinities of marinas. In addition, construction activities can lead to the
destruction of sensitive ecosystems and bottom-dwelling aquatic communities. The location of a
new marina facility means automatic condemnation of shellfish beds within a certain radius of that
facility. Given these facts it is clear that marinas should be designed and located so as to protect
against adverse impacts on shellfish resources, wetlands, submerged aquatic vegetation, and other
important habitat areas. Since boating facilities involve the use of publicly held water resources,
the location and expansion of marinas should be subject to a process which balances the need for
such uses against other identified community resource needs and objectives.
The comprehensive planning process also allows local governments the opportunity to
address riparian property rights with respect to community and individual as well as commercial
boat-related facilities Community facilities may be more appropriate in certain areas than
individual docks and piers because concentrating activities at community facilities may make
management of pollution sources easier. A waterway-by-waterway analysis of carrying capacity
is the best way to determine appropriate density for docks and piers, but may prove difficult.
Various measures may be enacted in land use ordinances which result in the retention of
waterfront areas as common open space.
For the first time, local governments can use the comprehensive planning process through
the shoreline element to proactively identify locations for both public and private access facilities
where impacts to water quality and marine resources will be minimized. These planning efforts
can ensure that the provision of access and boat-related facilities and activities are resource-based,
rather than demand-driven.
HRPDC Shoreline Study: A Regional Approach to State Regulatory Compliance
Because each locality in Tidewater Virginia is currently addressing the Phase II
implementation requirements of the Bay Act, the Hampton Roads Planning District Commission
(HRPDC) received a grant from Virginia's Chesapeake Bay Local Assistance Department and
Department of Environmental Quality-Coastal Resources Management Program in 1993 to assist
its thirteen Tidewater member jurisdictions in the preparation of their comprehensive plan
amendments, specifically the shoreline element. The Hampton .Roads Region consists of nearly
3,500 square miles and 1.4 million people. Oceans, bays, and major river shorelines amount to
more than 1,370 miles with hundreds of additional miles of shoreline along their tributaries. The
region includes a diversity of shoreline types, topographical characteristics, wave energy
environments, and aquatic resources. Combined with substantial waterfront access needs and
shoreline development pressures, Hampton Roads is a microcosm of the entire Bay watershed.
Designed to complete the required inventories and analyses on a cooperative, comprehensive, and
systematic basis, the HRPDC Shoreline Study should be a cost-effective undertaking for all
localities within the study area
The bulk of the study involved a comprehensive inventory and analysis of the following:
1) physical and oceanographic characteristics of the shoreline, including unaltered and altered
shoreline features (erosion control structures), shoreline miles, erosion rates and critically eroding
areas, bathymetry, flushing characteristics, current patterns, water quality, and environmentally-
sensitive areas/data on marine resources and habits, including wetlands, SAV beds, shellfish
producing, condemnation, and management areas, commercially- and recreationally-important
fisheries, habitats for birds of special concern, and protected areas, such as NERRS, natural areas
(Natural Heritage Sites) and areas of cultural or historical significance; and 2) public and private
access to shoreline areas, including location and number of private shoreline access structures,
particularly docks and piers on a shoreline reach basis, and the location of existing and proposed
public shoreline and water access areas or facilities.
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The presentation of data in the study is three-fold and is included in a Data Element, Micro
Documents, and a Map Folio. The Data Element contains: a definition of each type of data
collected and a regional overview of its abundance or characteristics; its significance to planning,
including discussion of the interrelationships among shoreline resources, characteristics, and
issues important to water quality protection; data collection methodology and sources; and, data
limitations. The Micro Documents contain a textual description of all data collected by river
system, system subarea, and waterbodies, mainstem segments, and reaches within each system
subarea. The Map Folio contains planimetric maps (1:200 or 1:400 scale) or other locally-
specified scale maps which document all shoreline erosion control structures, eroding or accreting
areas, and access structures and areas. The Map Folio also contains special scale maps
documenting selected marine resource, additional public access, and private access density data.
Each locality within the study area will also receive a low-altitude oblique video of its shoreline,
created and used during the study for data collection and shoreline analyses.
Following the Data Element, there is a discussion of shoreline erosion control and public
and private access issues, and presentation of generic policy options and recommendations which
can be tailored to the individual locality. For erosion control, common definitions of erosion rates
are given, erosion ranges are established, the range of erosion control techniques is explored, the
appropriateness of specific control techniques to erosion ranges is given, and a matrix of control
options given physical and oceanographic characteristics of the shoreline is presented. For
shoreline access, a methodology for determining regional and local demand for public access is
given, there is a discussion of shoreline and water quality impacts related to access development
and boating activity, a methodology is presented for determining the general suitability of
waterways for a range of access types, given physical and oceanographic contstraints of shoreline
areas, water quality considerations, and sensitive marine resources, access design criteria is
recommended, and restriction of private pier and dock densities and options for overall waterway
management is explored.
By synthesizing the many factors which create waterway or reach-specific shoreline and
water quality conditions throughout the region, with the growing body of published scientific data
on shallow water marine resources, this study will produce on its completion a single source
which can be used by local planners to develop locality-specific amendments to their
comprehensive plans regarding shoreline element issues. The study methodologies and policy
options presented appear to be transferable to other Mid-Atlantic regions.
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HYDRAULIC CLAM DREDGING EFFECTS ON NEARSHORE TURBIDITY AND
LIGHT ATTENUATION OF THE CHESAPEAKE BAY, MD
Katherine Keith Ruffin
Smithsonian Environmental Research Center
PO Box 28
Edgewater, MD 21037
Richard Everett and Douglas Forsell
U.S. Fish & Wildlife Service
Chesapeake Bay Field Office
Annapolis, MD 21401
INTRODUCTION
The Chesapeake Bay's estuarine waters support many commercial fisheries, one of which is
the soft-shell clam, Mya arenaria. The clam was originally harvested along the shallow waters of
the east coast using hand techniques until the early 1950s when the hydraulic dredge was
introduced (Figure 1). In the Chesapeake Bay, this new technique provided a quick method of
harvesting previously unattainable sub-tidal stocks of clams. The dredge is used in near-shore
waters (< 3 m) causing concern that this activity is negatively impacting biota, such as submerged
aquatic vegetation (SAY) that rely on this shallow habitat for survival. Hydraulic clam dredging
directly affects the environment by disturbance of the bottom substrate and by completely
uprooting all SAV in its path (Manning, 1957; Godcharles, 1971; Kyte & Chew, 1975).
Hydraulic clam dredging potentially indirectly affects SAV by producing suspended sediment
plumes which decrease water quality in the area of dredging.
We examined the effects of resuspended sediments on turbidity and light attenuation as a
result of clamming activity in nearshore waters. Specifically, we examined the following
questions:
1. Is there an increase in turbidity and light attenuation in dredge plumes relative to
regions outside of the plume and if so, what factors determine the magnitude of
that increase?
2. Does an increase in turbidity and light attenuation raise these parameters above
SAV tolerance levels established in the SAV Technical Synthesis, 1992?
3. How long after dredging ends do plumes persist?
4. What is the areal extent of plumes created by hydraulic clam dredging?
MATERIALS AND METHODS
Water quality was monitored along transects off of Eastern Neck Island, Chester River,
MD, an area of active clam dredging (Figure 2). Photosynthetic active radiation (PAR) and
turbidity measurements were taken at stations with water depths of 1.0, 1.5, 2.0 and 3.0 m. The
PAR measurements were used to calculate the light attenuation coefficient (Kd) for the water
column. Stations were categorized as "in" or "out" of a dredge plume and measurements were
compared between these areas. Bottom core samples provided grain size characteristics of
resuspended sediments.
Plume dissipation was monitored using both lagrangian and eulerian techniques. A drogue
(lagrangian) was used to track the water quality of individual plumes over time in order to
estimate how long it took for a parcel of plume water to return to background levels (Figure 3).
To determine eulerian dissipation of suspended sediments, turbidity and light attenuation time-
series were monitored at stationary locations within plumes.
In order to estimate plume sizes and boat locations in relation to bathymetry, existing aerial
photographs on which clam dredging activity was visible were examined. Plumes and boats were
digitized into a database using a geographical information system (ARC/INFO) and overlayed on
bathymetry data. The resulting coverages provided a random snapshot of clamming activity
which were analyzed for plume sizes and boat locations.
191
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RESULTS
Clam dredging had a significant negative impact on turbidity and light attenuation at all
depths when stations "in plumes" were compared with those "out of plumes" (Figure 4) (p <
0.001). A significant interaction occurred between depth and plume intensity with a greater effect
of dredging at shallow stations (< 1.0 m) compared to the deeper stations (p<0.05). Sediment
cores from the 1.0m stations had a higher silt and clay content than those from deeper stations.
•Drogue tracking of plumes showed that turbidity and light attenuation decreased
exponentially towards background conditions (Figure 5). Depending on the plumes initial values,
background levels of turbidity and light attenuation were reached in about 2 to 6 hours. These
times were greater for the drogues that followed plumes into water less than 1.0m where the
exponential slope of decay averaged to zero. Eulerian time-series of turbidity and light
attenuation within a plume showed background levels being approached in about 5 to 12 hours.
Examination of aerial photographs indicated that there was large variation in plume sizes: 1-
64 hectares for single boats associated with a plume. An overall average of 8 ha per boat was
estimated for the Chester River and 4.5 ha per boat for the Wye River. The majority of clamming
activity (71%) was found to occur in water depths less than 2 m.
DISCUSSION/CONCLUSIONS
Sediment size and water depth seem to be the major factors determining the initial
concentration of a suspended sediment plume created by hydraulic clam dredging. Decreased
water volume associated with shallow water coupled with the high silt/clay content of the near-
shore sediments caused the greatest increases in turbidity and light attenuation over background
levels. The average background levels of turbidity and light attenuation exceeded the SAV
tolerance levels at all depths, but was closest to meeting them at the 1.0 m depth. The presence
of a suspended sediment plume from clam dredging raises the turbidity and light attenuation far
above these tolerance levels, especially in the shallow waters.
Drogue and eulerian time-series of plume dispersion both showed exponential decay of
turbidity and light attenuation towards background values, This consistency over varying depths,
sediment type and current velocities suggests that, at least initially, grain size seems to be the main
criteria for plume dispersion. Water velocity and mixing become more important for the
dispersion of the silt and clay particles remaining in the water column, after the initial deposition
of the sand-sized particles. Increased resuspension of sediments due to waves and decreased
water velocity are two characteristics of shallow waters (Ward 1984, Signell & Butman 1992).
These shallow water characteristics will cause a slower dispersion rate of suspended sediments in
plumes located in shallow water compared to those in deeper water.
These results support the hypothesis that hydraulic clam .dredging contributes to increased
turbidity/light attenuation in the shallow waters of the Chester River, where SAV habitats occur.
While plants and animals in estuaries are adapted to dealing with episodic events of high
turbidity/low light, the cumulative effects of multiple days of clamming combined with naturally
occurring storm events may increase the stress above the threshold levels required to sustain
growth of SAV.
192
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REFERENCES
Environmental Protection Agency — Chesapeake Bay Program, 1992. Chesapeake Bay
submerged aquatic vegetation habitat requirements and restoration targets: A technical
synthesis, CBP/TRS 83/92, 186p.
Godcharles, Mark F., 1971. A study of the rFects of a commercial hydraulic clam dredge
on benthic communities in estuarine areas. Florida Department of Natural Resources,
Technical Series No. 64.
Kyte, Michael A. and Kenneth K. Chew, 1975. A review of the hydraulic escalator shellfish
harvester and its known effects in relation to the soft-shell clam, Mya arenaria.
Washington Sea Grant 75-2.
Manning, J. H., 1957. The Maryland soft shell clam industry and its effects on tidewater
resources. Maryland Department of Research and Education, Chesapeake Biological
Laboratory, Report No. 11.
Signell, Richard P. and Bradford Butman, 1992. Modeling tidal exchange and dispersion in
Boston Harbor. Journal of Geophysical Research, 97(C10): 15,591-15,606.
Ward, Larry G., W. Michael Kemp and Walter R. Boynton, 1984. The influence of waves
and seagrass communities on suspended particulates in an estuarine embayment.
Marine Geology, 59: 85-103.
193
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BOTTOM OF CUT TRENCH 'falf, ,s, "
Figure 1. Hydraulic clam dredge in operation. Modified from Manning (1957).
-------
Figure 2. Map of Chester River transect locations. Two meter
depth contour ( ).
195
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1.0 m
0.6 m
(0.3 m)
PVC Pipe (watertight)
Rip-stop nylon
PVC Pipe (open)
XT'
Figure 3. Schematic of drogue showing dimensions and deployment.
Small drogue dimensions are in parentheses.
196
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60
-H
•O
•H
I
s
c
0>
o
u
c
o
C
0)
40 _
20 -i
0
6
4 -
2 -
1.0
Turbidity
2.0
Depth (M)
Kd
3.0
Figure 4. Average turbidity and light attenuation coefficient (Kd) with
standard errors within (+) and outside (Q> plumes for April through October,
1993 and 1994. SAV tolerance (—) set by SAV Technical Synthesis . 1992.
197
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Drogue/Plume moving offshore
m=-0.004
1.4 -
m=-0.0015
120 180 240 300 360
120 180 240 300 360
>i I 4-
U •>••«
•H
•a 1.2-
-H
XI
M
EH 0.8-
1.0-
« °-6H
•M
U 0.4-
•H
H 0-2-
0.0'
Drogue/Plume moving inshore
m=0
60 120 180 240 300 360
120 180 240 300 360
o.O
Eulerian Time-series
m=-0.002
i i
60 120 180 240 300 360
Time (min)
1.4
m=-0.001
120 180 240 300 360
Time (min)
Figure 5. Drogue and Eulerian time-series plots with exponential curves
and mean slope.
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DEVELOPMENT OF A DREDGED SEDIMENT CONTAMINATION REDUCTION
PLAN FOR THE NEW YORK/NEW JERSEY HARBOR ESTUARY
Dennis J. Suszkowski
Hudson River Foundation
40 West 20th Street, 9th Floor
New York, NY 10011
Several million cubic yards of sediment are dredged each year from channels and berthing
areas in the New York/New Jersey Harbor Estuary and dumped at an offshore disposal site in the
Atlantic Ocean (Figure 1). The sediments are mostly fine-grained and are subject to severe
contamination from nearly three billion gallons of point-source municipal and industrial
wastewater, stormwater, combined sewer overflows, leakage from Superfund Sites, and air
deposition Consequently, this contamination by organic and inorganic chemicals is constraining
continued ocean disposal and prompting the evaluation of new dredging options, particularly ones
that can accommodate large volumes of contaminated material.
Within the past few years, the testing requirements for the ocean disposal of dredged
material from New York Harbor have been revised. New protocols for amphipod toxicity testing
and dioxin analyses in both dredged sediments and test organisms have shifted the classification of
harbor sediments toward a higher percentage of "contaminated" material. Table 1 shows how
dredged material is classified by the New York regional offices of the Corps of Engineers (Corps)
and the Environmental Protection Agency (EPA). Before the new protocols were implemented,
approximately 80% (by volume) of material dredged from New York Harbor was classified as
Category 1 (i.e., material shown to be non-bioaccumulative and non-toxic). Until the new
procedures were implemented, no material had ever displayed toxicity at levels sufficient to
classify it as Category 3, thereby prohibiting it from being ocean dumped. Approximately 20% of
all material was routinely found to demonstrate some bioaccumulation potential (Category 2), but
the effects could be mitigated through the use of capping at the ocean dump site.
The new testing requirements have resulted in more material being classified as Category 2
and 3. The most serious consequence of this is that Category 3 material, estimated to be about
30% (U.S. Army Corps of Engineers, 1995) of all proposed dredged sediments, does not have an
acceptable large-scale disposal site anywhere in the region. The only large project involving
Category 3 sediments to be dredged recently involved the transport of the dredged material from
New York Harbor to Texas by barge. Then, the material was rehandled and placed in railroad
cars and sent to Utah for final disposal in a landfill. The cost of this project was about $118 per
cubic yard as compared to $5 per cubic yard, the average cost of ocean disposal in 1989 without
capping (O'Connor, 1989).
Given the prohibitive costs of disposal of contaminated material and the environmental
concerns about the possible effects, there is broad agreement among federal and state
governments, environmental organizations, the Port Community, scientists and the general public
that a comprehensive plan be developed to reduce sediment contamination such that expensive,
confined disposal options and decontamination will not be necessary in the future. Two major
management programs, the New York/New Jersey Harbor Estuary Program (a component of the
National Estuary Program) and the Dredged Material Forum (a special multi-organization effort
convened to develop a short- and long-term dredged material disposal plan for New York
Harbor), have joined together to develop and implement a reduction strategy. Because of the
overlapping authorities of both plans, particularly as they relate to contaminant reduction, the
Forum has been incorporated into the Harbor Estuary Program (HEP). Just prior to the merge, a
special work group was established to develop a contaminant reduction plan that would review
the current toxics control strategies already recommended by HEP, determine whether they would
be sufficient to reduce future dredged material contamination, and if not, recommend additional
actions As a guideline, the work group was asked to recommend a plan that would result in the
classification of all future dredged material as Category 1, and to assess when, if ever, this could
be achieved.
After several months of work, the Sediment Contamination Reduction Work Group (Work
Group) recommended a strategy that has since been incorporated into the New York/New Jersey
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Harbor Estuary Program's (1995) proposed Comprehensive Conservation and Management Plan
(CCMP). The contaminant reduction plan is depicted in schematic form in Figure 2. Many of the
tasks included in the strategy were already incorporated into the CCMP. Others, highlighted in
the figure as "new" are ones that were suggested by the Work Group. The sediment
contamination reduction plan has both an assessment phase (shown on the left side of the figure)
and an action plan (shown on the right). Basically the plan calls for: (1) identifying the
contaminants of concern, (2) delineating and quantifying their sources; and (3) implementing
strategies to reduce or eliminate them from entering the estuary.
Four contaminants have been identified as probable causative agents in classifying harbor
sediments as "contaminated" (i.e., Category 2 or 3). PCBs, dioxin, and mercury have been shown
to bioaccumulate in test organisms, thereby classifying the sediments as Category 2 material.
Dioxin has been measured in sediments at concentrations which categorize them as Category 3.
Substantial amphipod toxicity has also been demonstrated and consequently sediments have been
classified as Category 3, but the causative agent or agents have not been identified, although
polycyclic aromatic hydrocarbons (PAHs) are suspected. The results of ongoing and new Toxic
Identification Evaluations (TIEs) will be needed to confirm or deny the role of PAHs, and any
other chemicals, in causing the observed toxicity. There are several regulatory programs currently
operating under state and EPA authority which can be used to eliminate the flow of these
pollutants, but they have never before been used to alleviate sediment contamination. The Work
Group recommended, and has since received, commitments from EPA and the States of New
York and New Jersey that dredged material criteria contraventions constitute enforceable
violations and can thereby be linked to ongoing regulatory programs. This is a major step
forward, making this region the only one in the U.S. that now has a legal and regulatory
connection between dredged sediment contamination and pollutant abatement.
The Work Group recognized that technical knowledge is seriously lacking in certain critical
areas, thereby limiting the implementation of an estuary-wide reduction effort. Therefore, several
new actions were proposed as part of the assessment phase of the plan. A major new suggestion
of the Work Group was the development of a predictive tool to provide answers to "what if
questions about various reduction strategies. For instance, what future concentrations of dioxin
can be expected in dredged sediments if a major source in the Passaic River is eliminated? And,
what reduction in bioaccumulation potential from those sediments can also be expected? Overall,
however, the Work Group was interested in a preliminary assessment within the next two to three
years as to when all harbor sediments could be expected to be Category 1. This assessment is
intended to coincide with decisions to be made concerning long-term disposal options. This
information will be particularly relevant toward planning the life span of containment facilities that
will certainly have to be built to handle large volumes of contaminated dredged sediments. After
several meetings and a technical workshop, it was agreed that an existing PCB bioaccumulation
model (Thomann et. al, 1989) be recalibrated with respect to PCBs, expanded to include dioxin
and PAHs, and then used to predict future sediment and biota concentrations in light of various
contaminant reduction scenarios. The Hudson River Foundation, with additional financial support
from the Corps of Engineers, EPA, and the Port Authority of New York and New Jersey, has
awarded a grant to Manhattan College investigators to undertake this further model development.
The only major task that remains unfunded at present is the identification and quantification
of sources of contaminants of concern, particularly dioxin and PAHs. This information is critical
to both the modeling effort and any reduction measures that could be implemented in the short-
term without the modeling results. Without this information, a comprehensive contamination
strategy can never be implemented.
In summary, the status of the sediment contaminant reduction strategy is as follows:
• The plan presented in Figure 2 has been endorsed by all of the groups and
organizations participating in HEP is now part of the draft CCMP;
• Dredged material criteria contravention can now trigger implementation of specific
pollutant control programs operated by EPA and the states;
• The predictive food chain transfer modeling effort has begun; and
• Resources need to be secured for all elements of the plan, however, funding for
identification and quantification of contaminant sources is critical.
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REFERENCES
New York/New Jersey Harbor Estuary Program. 1995. Proposed Comprehensive
Conservation and Management Plan - February 1995. 260 p.
O'Connor, J. 1989. Managing Dredged Material: An Evaluation of Disposal Alternatives in
the New York New Jersey Metropolitan Region. Report prepared for the U.S. Army
Corps of Engineers, New York District. New York University, Institute of
Environmental Medicine, Tuxedo, NY. 125 p.
Thomann, R.V., Mueller, J.A., Windfield, R.P. & C-R. Huang. 1989. Mathematical model
of the long-term behavior of PCBs in the Hudson River Estuary. Final Report to the
Hudson River Foudation, New York, NY. 234 p.
U.S. Army Corps of Engineers, New York District. 1995. New York Harbor Dredged
Material Management Plan: Phase 1 Report - Plan of Study. July 1995. New York,
NY.
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Table 1: Classification of New York Harbor Dredged Material and Current Disposal Options
CATEGORY
DESCRIPTION
DISPOSAL OPTIONS
No bioaccumulation
No toxicity
Ocean disposal
Beneficial uses
Bioaccumulation
No toxicity
Ocean dumping
with capping
Small-scale upland
Tpxcity and/or
Bioaccumulation
No current large-scale
options
Small-scale upland
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Figure 1. Maintenance Dredging Quantities of Fine-grained Material from
New York Harbor. The total average yearly volume is
approximatley 4.3 million cubic yards. The federal government
(i.e., the Corps of Engineers) dredges about 2.9 million cubic
yards annually while all others (shown as "Private") dredge the
remaining 1.4 million cubic yards.
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Figure 2. Sediment Contamination Reduction Plan
Bioaccumulatipn •
Results •
f
ID Contamir
of Concern <
^^^T
TIEs
(new)
T
lants •
new) |
1 ID Sources of |_
Year Contaminants
1
(new) •
<
Develop & Apply Simple
. _ Models/Tools -
Preliminary Assessment of
Years Hartoorwide Reduction
in Relationship to
Long-Term D.M. Plan
(new)
T
5 Full Assessment
using Long-Term
Years Modeling effort
_J
Estimate Chemical •
Load Reductions 1
(new) 1
i _i_ i
^ T
.
J
1
-^
Select Program(s)
i
(1) Trackdown & Cleanup
(2) CSO/SW Abatement
(3) Pollution Prevention
(4) Waste Site Inventory
f
Implement
Reduction
Efforts
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SIMULATION OF A SHALLOW ESTUARINE ENVIRONMENT
WITH A NOVEL MICROCOSM DESIGN
Thomas W. Small
StephenB. Gough3
Department of Biological Sciences
Mary Washington College
Fredericksburg, VA 22401
ABSTRACT
New microcosm designs that more faithfully reproduce ecosystems over long periods have
been developed (Adey & Loveland, 1991). Unique to these systems is the employment of algal
mats to remove excess nutrients and other waste products. Also, they are primarily self-sufficient.
To date, research has concentrated on large synthetic environments (e.g., a two million liter Great
Barrier Reef system); less work has been done on smaller, more manageable units. Thus, while
the potential for using encapsulated ecosystems for fundamental environmental research and
ecological damage assessment is great, the concept is fraught by high construction costs
($150,000 to an excess of $1,000,000). To test an alternative method, we have constructed a
smaller scale, inexpensive ($7,000) 2,000 liter self-sufficient algal turf-based system that emulates
a shallow estuarine site on the York River in Virginia. We are assessing biological and
physicochemical stability and are comparing the results with (a) organisms maintained in the
laboratory under traditional (non-microcosm) conditions and (b) biotic and abiotic components of
caged areas at the emulated York River site. To date, the microcosm is virtually self-sufficient
and is successfully supporting population of species that are abundant in the York River
ecosystem.
INTRODUCTION
During the past fifteen years, the Marine Systems Laboratory (MSL) of the Smithsonian
Institution has pioneered the design and construction of mesocosms and microcosms based on an
innovative design. These systems utilize turf algae to remove animal waste, balance pH and
oxygenate the water, this is distinctly different from the more commonly employed bacterial,
chemical, or physical filtration methods (Adey & Loveland, 1991). Because the algae-based
water treatment method is more closely akin to natural water processes, it is believed to produce a
more authentic environment for resident organisms (Adey, 1983).
The MSL microcosms and mesocosms built to date are functioning ecosystems that have
little or no import or export of nutrients. They are designed to emulate specific environments that
encompass a variety of ecosystem types. The major marine mesocosms include a 15,300 liter
Caribbean reef and lagoon environment (established in 1980), a 10,000 liter subarctic Maine rocky
shore and marsh environment (established in 1985), and a 2,800,000 liter Great Barrier reef
environment (established 1987). MSL has also produced two estuarine mesocosms: a 60,000 liter
Chesapeake Bay environment (established in 1986; project terminated in 1994 and reestablished
as a 72,000 liter Delaware Bay environment) and a 44,000 liter Florida Everglades system
(established in 1988). Both estuarine systems maintain a salinity gradient from fresh (0 ppt
salinity) to marine (30 ppt salinity) via mixing gates and tidal mixing actions, respectively. MSL
has also developed numerous aquaria style microcosms that range in size from 120 liter to 520
liters, although results indicate they are limited in their ability to replicate natural systems (Adey &
Loveland 1991; Lucket, pers comm.).
So far, the primary use of these systems has been educational, and many of them are on
public display or are used in high school and college curricula. Because these environments are
maintained entirely in the lab, many of the variables that plague certain forms of field research can
be controlled. Parameters such as weather, temperature, wave action, tidal range and organismal
migration can be regulated. However, the large size and high cost ($150,000 - multi-$l,000,000's)
3 To whom inquiries should be addressed. Phone: 540-654-1422; Fax: 540-654-1081
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of many of the mesocosms place them out of the range of most research endeavors, while the
smaller aquaria style systems bear little "ecological" resemblance to their parent ecosystems.
Another problem faced in microcosm research is that many scientists are skeptical about how
faithfully they represent the ecosystems they are meant to emulate (Westman, 1985).
This project examines the viability of using intermediate-scale inexpensive microcosms,
based on the MSL design, in environmental research and education. A prototype system has been
designed and constructed, and we are currently assessing its performance.
MATERIALS AND METHODS
The microcosm was constructed at Mary Washington College, Fredericksburg, Virginia,
over the summer of 1994 (Figure 1). It is designed to emulate a shallow shoreline environment
along a mesohaline (ca. 15 ppt) portion of the York River, Virginia, at the York River State Park.
It holds approximately 2000 liters of water and 1.3 cubic meters of soil and sediment. The
shoreline portion of the system consists of a sandy beach, a marsh and a muddy fiddler crab
embankment. The tidal range is 10 cm (measured vertically) which translates into about a 41 cm
tidal flux along the shoreline. This intertidal zone comprises about two-thirds of the shoreline's
area. At high tide, the entire sandy beach is covered, only 8 cm of the lower marsh is exposed,
one half of the muddy fiddler crab embankment is submerged and the high marsh (above the
muddy embankment) is unaffected.
The aquatic portion of the microcosm is 0.5 meters deep at high tide and 0.4 meters deep at
low tide. The shallow water environment is divided into a near shore sandy bottom and a muddy
bottom farther from shore. The right side of the microcosm has been set aside as an elevated
emergent grass bed whose depth ranges with the tide from 13 to 23 cm.
SUPPORT UNIT
A "support unit" is affixed to the end of the tanks to regulate various environmental
parameters so that the laboratory system replicates the York river environment as closely as
possible. This unit consists of seven major functional parts.
The wave generator
Mild wave action is an important parameter at the York River site. To recreate this in the
lab, a "dump bucket" wave generator is used. A pivoting bucket is attach at a point
approximately 0.35 m above the water line. When empty, the bucket's center of gravity is bellow
the pivot point, thus it is suspended upright. As water flows into the bucket and fills it, the center
of gravity shifts to above the pivot point, causing the bucket to tip over. The periodic surges of
water that enter the system create waves with an amplitude of about 2 cm. However, by adjusting
the size of the bucket and/or the inflow rate, the intensity and/or period of the wave action can be
adjusted.
Natural light replication
Three 1000 watt metal halide bulbs are positioned over the main tanks and a single 1000
watt bulb overhangs the scrubber. The average spectral characteristics of these bulbs is about
4000° K, and incident PAR at the shoreline and the water surface is estimated to be about one-
third noontime summer solstice values. Timers are used to automatically adjust lighting to
coincide with sunrise and sunset, and the length of the light period is adjusted to correlate with
seasonal changes.
The tide generator
The tides are controlled by a slow stepper motor attached to a flexible tube that acts as a
drain for the main tank. This motor is set to make two full revolutions in a day. As it turns, it
moves an arm that is attached to the motor shaft, consequently lifting or lowering the drain. The
outflow of the drain enters the tidal reservoir, which contains a pump that returns water to the
main tank. As this process continually occurs through out the day, the water level in the tank
raises and lowers with the drain height, producing two high and two low tides a day.
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Heat exchanger
Temperature changes in the water represent an important seasonal variable. To control
water temperatures in the microcosm, a heat exchanger is used. System water passes through a
box that contains 29 m of glass tubes that have chilled fresh water passing through them. Heat
from the microcosm is absorbed by the fresh water in the pipes and carried into a fresh water
reservoir where the water is rechilled. The microcosm water and the fresh water coolant never
mix. This indirect method of controlling temperature is used instead of directly chilling the water
because it is believed to be less harsh on the plankton, since they are not entrained in a potentially
stressful cooling circuit.
The refugium
Because of the small size of this system, there are few protected areas that allow some of
the more delicate or highly preyed upon species to flourish. An in-line refugium provides shelter
for such organisms. It is simply a 80 liter tank that has no wave action and is devoid of higher
predators, such as fish and crabs. The water is pumped into the refugium from the tidal reservoir
and flows back out into the wave generator via a stand pipe.
Wind
Wind is created by using a house fan suspended above the system and directed at the
shoreline. Velocities at the front of the shoreline average 1.7 m/s.
The algal turf scrubber (Figure 2)
Easily the most radical departure from more traditional microcosm design is the use of turf
algae for water treatment. By using plants to remove animal waste, regulate dissolved gas
concentrations and to control pH, the algal turf scrubber attempts to replicate the natural process
of water restoration. The scrubber consists of a plastic screen, which algae are cultured on,
suspended in a tray of water. Water enters the tray via a dump bucket wave generator, which
replicates the heavy surf environment where many turf algae are found. Water then drains out
from the opposite end of the tray. A single 1000 watt metal halide bulb provides light for
photosynthesis. PAR at the mat surface is estimated to be 90% of the noontime summer solstice
value.
The light cycle over the scrubber is opposite from that in the main tank. During the day,
when the main tank is illuminated and the plants in the tank are using nutrients and releasing
oxygen, the light over the scrubber is off In the evening, when the main tank lights go off, the
scrubber light turns on, thus stimulating photosynthesis and chemical rejuvenation. The entire
scrubber and light are encased in a light shield to prevent contaminating the main tank with
unnatural nighttime light levels.
Each week the scrubber screen is "harvested," during which time most algae are removed
from the screen. The algae remaining on the screen then go through a fast regrowth phase and
they quickly take-up nutrients and release oxygen into the water. The algae removed from the
screen are dried and weighed to keep a record of primary productivity of the scrubber, and the
dried biomass is returned to the system over the following week to prevent nutrient loss.
RESULTS AND DISCUSSION
The physical construction of the microcosm ended in August of 1994. Collections of soil,
bottom sediments and 750 liters of York River water (15 ppt salinity) were placed in the
microcosm in October. During this time, an additional 750 liters of artificial sea water was
manufactured (also 15 ppt salinity) and used to top off the water level. From mid- to late-
November, animals and vascular plants were collected and introduced into the microcosm. In
April of 1995, a second addition offish was made to compensate for early fatalities. No other
items were added to the system except for fresh, deionized water which compensated for
evapotranspiration (losses averaged 35 L/wk and the relative humidity in the room averaged
77%). In addition, 95 L aliquots of York River water were added every three to four weeks; the
purpose of these augmentations was to give the system a periodic influx of new plankton.
A list of the dominant species introduced into the microcosm follows:
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Dominant Species TJsf
PLANTAE
Spartina alterniflora Smooth Cord Grass | Triplasis purpurea Purple Sand Grass
Juncus gerardi Black-grass | Ivafrutescens Marsh Elder
Bpltonia asteroides White Boltonia | Ulva lactuca Sea Lettuce
Enteromorpha sp. Hollow-tubed seaweed
CHORDATA
Menidiasp* Silversides | Trinectesmaculatus Hogchoker
Micropogonias undulatusAtlanlic Croaker j Fundulus grandis' Gulf Killifish
Fundulus heteroclitus'Mumimchog \ Molgula manhattensis Sea Squirt
MOLLUSCA
Littorina irrorata Marsh Periwinkle | Geukensia demissa Ribbed Mussel
Mulinia laterahs Little Surf Clam
ARTHROPODA
RithropanopeusharrisiiWhite-fingered \ Ucaminax Brackish-water
Mud Crab Fiddler Crab
Balanus improvisus Bay Barnacle | Callinectes sapidus Blue Crab
Palaemonetes sp. Shrimp \Orchestiaplatensis Beach Flea
CNIDARIA
Diadumene leucolena Ghost Anemone
'extra individuals added in April 1995
From the beginning of December through May, the microcosm went through a period of
"stabilization." During this time, the organisms were given an opportunity to become acclimated
to the synthetic system. It is often the hardiest of the organisms that survive and flourish in the
earliest stages of stabilization, but as more organisms establish themselves, the environment
becomes more hospitable to other species. Also during this time period, any problems with the
system design can be resolved. Our system underwent modifications in algal turf removal
frequency, light intensity/duration, temperature regulation and the amount of silty sediment in the
deep water zone.
Our two most significant design problems involved temperature regulation and turbidity.
The original heat exchanger did not transfer heat efficiently enough to produce winter water
temperatures. Consequently, the microcosm did not undergo a wintering period this year. A
new, more efficient heat exchanger is now in place and functioning well.
The problem of turbidity has also been solved. Early on, light only penetrated 4 to 5 cm
into the water column because of excessive suspended s.olids. This problem persisted on and off
until mid-April, when repeated attempts to produce greater clarity finally succeeded. As a
consequence of the turbidity, a stand of emergent grass died out because new submerged growth
could not survive in the low light environment. High turbidity has also been the reason no
attempt has yet been made to establish submerged aquatic vegetation (SAY).
Water chemistry appeared to stabilize at "healthy" levels after the algal scrubber began
functioning in mid-December. The dissolved oxygen concentration of surface waters has been
very similar to the natural site. For example, readings taken at the York River on March 25
displayed a DO of 7.2 mg/L (read at 14.5° C) while the microcosm had a DO concentration of
7.0 mg/L (read at 17.0° C) on April 1. Since that time, there have been no apparent problem with
DO concentrations. Nitrate concentrations have stabilized at an average of 0.19 ppm compared
to 0.15 ppm found at the York River State Park. Phosphate concentrations were stable, although
somewhat high, averaging around 0.98 ppm in mid-May in comparison to a concentration of 0.19
ppm found at the York River. Since June, the concentration of phosphate has jumped to 3.0 ppm.
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This has resulted in blooms of blue-green algae and a decline in other algae species. The
phosphate problem is believed to be a result of a contaminated fresh water supply used to
compensate for evaporation in the microcosm. Plans are presently underway to confirm this as
the sole source of phosphate enrichment and to remedy the problem.
By mid-January, some organisms had begun to thrive in the early microcosm environment.
First to colonize the unpopulated tank walls, scrubber bed, and refugium, was Molgula
manhattensis (Sea Squirt), Mulinia lateralis (Little Surf Clam), Diadumene leucolena (Ghost
Anemone) and Balanus improvistis (Bay Barnacle). All of these are well represented in the
natural environment.
Arthropods also are doing well in the microcosm. Amphipods and copepods are routinely
located along the beach and Rithropanopeus harrisii (White Fingered Mud Crab) can be found on
just about any rock or debris that can be removed from the water.
Blue Crabs (Callinectes sapidus) were only introduced as juveniles because jt was
believed that the environment could not support an adult's dietary needs (Adey & Finn, 1991).
During the initial organism introductions, four juveniles were added to the microcosm. Their .
average weight was 9.3 grams and mean carapace dimensions were 3.7 cm by 2.6 cm. In April
1995, a dead adult blue crab weighing 97.0 grams (carapace dimensions not take) was recovered
from the system. In May 1995, a living adult was removed from the system weighing 116.3
grams (carapace dimensions 10.6 cm by 5.0 cm) and was returned to the York River to avoid
overtaxing the environment. One Blue Crab is known to still survive in the microcosms (weight
29.4 g, carapace dimensions 6.8 cm by 3.5 cm) but the future vitality of Blue crabs in the
microcosm is uncertain.
Individuals from all fish species introduced into the system, except for Trinectes
maculatus (Hogchoker), have been sighted at least once since March 20. The Hogchoker's
absence is not surprising since it is adept at hiding in the bottom sediment (Lippson & Lippson,
1984).
All the surviving shoreline plant species are doing well. After the initial relocation, much
of the plant foliage died off but some completely regenerated within three weeks. Even though
some species placed in the microcosm did not survive (mainly those from the high marsh and
largely Lythrum lineare, Juncus Roemerianus and Panicum virgatum), attempts will be made to
reintroduce them at a later date.
It appears that the model system has successfully stabilized and will be ready in early fall
for studies that will compare it to the York River reference site. Four main studies will be
undertaken: stress levels in fish (fish maintained in a bacteria filtered aquarium also will be
examined), gut content analysis offish, plankton diversity and density, and periphyton succession
on an artificial substrate.
This project has achieved the goal of designing and creating an inexpensive and space-
conserving encapsulated, simulated ecosystem based on an algal scrubber design. Despite the fact
that there has been no nutrient import or export (except for the addition of York River water),
many of the organisms introduced into the microcosm in October of 1994 are still alive, and some
are thriving. This strongly suggests that the unit is a functioning ecosystem with at least a
reasonably sound food web and nutrient cycle. However, as of yet, there is no evidence that
either the food web or the nutrient cycle bears any significant resemblance to that of the York
River. Further studies over the next two years will begin to answer questions about its suitability
as a tool in ecological research.
ACKNOWLEDGEMENTS
We thank the Marine Systems Laboratory staff of the Smithsonian Institution for technical
advice and supplies. The interest, cooperation and patience of the York River State Park staff is
greatly appreciated and was immensely helpful. Sincere thanks are also due to several students
and Smithsonian personnel who helped maintain and construct the mesocosm and who
participated in the collection of organisms to stock it. Other Mary Washington College Biology
faculty were instrumental in the success of this effort, and we appreciate their tolerance of
periodically flooded floors and other inconveniences. This research was partially funded by a
Mary Washington College Undergraduate Research Grant to the senior author.
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LITERATURE CITED
Adey, W. H. 1983. The microcosm: a new tool for reef research. Coral Reefs 1:193-201.
Adey, W. H. and M. Finn. 1991. Mesocosms: encapsulated ecosystems on display. Sea
Technology 32(4):85.
Adey, W. H. and K. Loveland. 1991. Dynamic aquaria. Academic Press, San Diego.
Lippson, A.J. and R. L. Lippson. 1984. Life in the Chesapeake Bay. The Johns Hopkins
Univ. Press, Baltimore.
Westman, W.E. 1985. Ecology, impact assessment and environmental planning. John
Wiley, New York.
210
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2.4 m
Figure 1: Schematic diagram of the MWC York River Microcosm. Functional
elements include: A) Microcosm (shore line on the left and dump bucket/wave
generator on the upper right), B) Metal Halide lights, C) Tide control arm, D)
Tide reservoir, E) Heat exchanger, F) Refugium, G) Algal Turf Scrubber with
light shield. Dotted lines indicate water flow.
SCRUBBER
400-1000 watt
metal halide
lights
Water inflow
Wave surge
bucket'
Algal turf screen'
Figure 2: Schematic of the algal turf scrubber subsystem used for chemical
stabilization of the microcosm. (From Dynamic Aquaria: Building Living
Ecosystems by Walter H. Adey and Karen Loveland, Copyright (c) 1991 by
Academic Press, San Diego. Reprinted by permission.)
Figures 1 and 2
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COMPETITION, NICHE BREADTH AND NICHE OVERLAP IN TWO SYMPATRIC
ESTUARINE KILLIFISHES: A TEST OF ECOLOGICAL THEORY
Craig Steele,* Brian Zeppenfeld Kenneth Smith
Dept. of Biology and Health Services Dept. of Biology
Edinboro University Shippensburg University
Edinboro, PA 16444 Shippensburg, PA 17257
Jennifer Belvick, Kevin Dreher, Melissa Stefry
Michelle Jameson, Michael Mattis, Dept. of Biology
Guy Wiggins Kutztown University
Dept. of Biology Kutztown, PA 19530
Millersville University
Millersville, PA 17551 Timothy Teaford
Dept. of Biology
David Moffatt California University
Dept. of Biology California, PA 15419
Saint Francis College
Loretto, PA 15940
Chad Walizer
Dept. of Biology
York College
York, PA 17403
*Author to whom correspondence should be addressed
ABSTRACT
Mummichog (Fundulus heteroclitus) and striped killifish (F. majalis) sympatric killifishes
with similar eco-morphology, were collected from Tom's Cove, Assateague Island, VA
(mummichog, N=83; striped killifish, N=90). Gut content analyses followed standard procedures
(Yap, 1988). Results of the analyses were compared using Schoener's Index for niche overlap by
measuring components of the fishes' stomachs both by wet weight and by type. According to
standard ecological theory, diet overlap is expected to increase with increasing food abundance in
estuaries during summer months; significant overlap (^0.90) in the diets of the two species was
thus expected. However, only moderate overlap was indicated in this study (0.56 to 0.62).
Measurements of niche breadth using occurrence frequencies with Gladfelter-Johnson's index of
niche breadth (modified by Cardona, 1991) indicate that, in our study area, striped killifish have
about twice the niche breadth as mummichog (B'=0.134 and 0.088, respectively). Active selection
of particular prey taxa from the two available prey sources (water column and substratum),
mediated by apparent species-specific differences in foraging behavior, resulted in interspecific
differences in type, number, and weight of prey consumed. Striped killifish fed extensively on food
items from the substratum, including molluscs (primarily clams) and annelid worms; mummichog
did not. These two species appear to be partitioning the resource even under apparent conditions
of ample food availablility.
METHODS
A range of similar-sized specimens of both species were collected by seining from Tom's
Cove, Assateague Island: mummichog (Fundulus heteroclitus) N=83; striped killifish (Fundulus
majalis) N=90. The fish collected were immediately placed into 10% formalin solution; they were
all processed within the next two days. Frequency distributions of numbers of individuals of each
species for different standard length (cm) ranges are presented in Figure 1.
Gut content analyses followed standard procedures similar to those of Yap (1988) and
Burrell (1992). The food mass of a preserved specimen was removed as a single lump. The mass
was transferred to a crystalizing dish under a dissecting micrscope and teased apart. Food
contents were separated, counted, and categorized to the furthest possible taxonomic level. Each
212
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taxon was then placed on a filter paper to remove excess moisture, then transferred to a
pre-weighed filter paper and weighed on a tared analytical balance to the nearest 0.1 g. A record
was maintained of each specimen by number, along with its standard length and gut contents.
Total weights of each taxon for each species of killifish were used to determine their percentage
weights in relation to the total diet. Food contents were thus analyzed by both frequency of
occurrence (counts) and by percentage of total mass. No one method of stomach analysis
provides a complete picture of the dietary importance of a taxon; this combination of amount and
bulk was employed to enhance the measurements.
Schoener's (1970) dietary coefficient was used as the index of niche overlap. After
analysis of all stomach contents, it was evident that many categories were represented by few
individual food items Food items were, therefore, grouped into eight major categories, based not
only on taxa, but also on location of the prey source and capture method required: horseshoe
crab larvae; horseshoe crab eggs; molluscs; small crustaceans; annelid worms; fish eggs; fish
larvae; fish. The formula for calculating Schoener's overlap index is as follows:
R
Ou = 1 - 0.5 Sum |Pta- PjJ
a
Where Pia and Pja are the proportions of diets offish species i and j which are composed of food
a, R is the number of food categories; and O is the overlap coefficient for the diet between species
i and j. The index gives resultant values between 0 (no overlap) and 1 (complete overlap).
Niche breadth of the two species was examined using occurrence frequencies (counts) of
the food categories with Gladfelter-Johnson's (1983) index of niche breadth (as modified by
Cardona, 1991). The formula for this index follows:
B' = Sum(fi - s^
100 R
Where Sfi is Gladfelter-Johnson's index; s is the standard deviation of occurrence frequencies; and
R is the number of food categories.
RESULTS AND DISCUSSION
Proportions of the total diet of the different food types by frequency of occurrence and by
weight, and the overlap coefficients for each dietary measure are given in Table 1 and Table 2,
respectively. The niche breadth coefficients are: B1 = 0.088 for mummichog; B' = 0.134 for
striped killifish. Food types found are considered to be reflective only of the habitat from which
the fish were captured and only for the season and year (August 1993) of the study; food
resources are known to fluctuate both temporally and spatially.
The overlap coefficients for both dietary measures indicate only moderate overlap in the
diets of the two species, as defined by Keast (1978). These results are surprising because diet
overlap is expected to increase with increasing food abundance, especially in estuaries during
summer months, and are quite different from those found by Baker-Dittus (1978). She conducted
a study of the foraging patterns of mummichog and striped killifish off Seagull Beach and Broome
Island on the Patuxent River Estuary, Prince Frederick County, Maryland. Schoener's overlap
coefficents calculated for August, 1978, from data presented in her paper are: O = 0.72 for
frequency of occurrence; and O = 0.81 for weight.
At least three hypotheses could account for the observed dichotomy in the foraging
behavior of mummichog and striped killifish in our study. First, the two species (or, at least these
two populations) may be genetically programmed, through natural selection and distal competitive
interactions, to partition the food resources even in times of apparent ready food availability. A
second and equally plausible hypothesis is that the two species differ in foraging behavior as a
result of phylogenetic constraint, i.e., foraging behavior and/or prey handling characteristics are
traits fixed within each lineage and involves no previous competition or ecological relationship
between the two species. A third (unlikely) explanation is that mummichog are excluded by
striped killifish from feeding in those microhabitats where the molluscs occur.
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Support for the first and second hypotheses was found by observing single-species schools
of mummichbg and striped killifish brought back to the laboratory and maintained for two weeks
in aquaria. Mummichog readily ate commercial fish flakes from the surface; striped killifish would
not feed on flakes floating on the surface but would readily feed on them when they had sunk to
mid-water or the bottom of the aquarium. For the first week-and-a-half, striped killifish were
rarely found above the mid-water level in the aquarium; only at the end of the two weeks of
observation were they beginning to swim often above mid-water and to begin feeding at the
surface. Striped killifish, at least in the laboratory, appear to prefer to swim and feed near the
bottom and appear "reluctant" to venture near the surface.
Future studies will be directed at attempting to distinguish between the first and second
hypotheses in explaining the resource partitioning observed between these study populations even
during a time of apparent plenty. Because foraging patterns may vary within a species due to
habitat as well as seasonally, future studies will focus on comparing the foraging patterns of these
species from other sites in the Wallops Island area and on specific microhabitats within a study
site. In addition, such measures as gape width- volume of food, and weight of food all
standardized for fish lengths should be included in future studies to better control for different
numbers of individuals in the size ranges (see Figure 1) and for gender-based differences in
growth in these species (Steele et al., unpub. data).
SUMMARY AND CONCLUSIONS
It is important to incorporate ecological theory into management practices.'Ecological
theory, however, must be supplemented by direct investigations of ecosystem functioning. With
the abundance of food available in estuaries during the summer months, ecological theory
predicted considerable diet overlap in these two species. Only moderate overlap was found,
however, in the diets of the studied populations of these species during a part of the season when
considerable overlap was expected. Niche breadth of the stiped killifish collected is nearly twice
that of the mummichog examined. Although several hypotheses have been suggested to explain
our observations, none can yet be distinguished to explain the observed resource partitioning
during a time of ready food availability.
If an incident were to drastically reduce the benthic fauna of the system, both species
would be predicted to survive equally well. The extensive selection of prey from the substratum
by striped killifish, however, could not be predicted by broad-perspective theory. Not considering
species-specific differences in foraging behavior and food selection, even between species with
similar eco-morphology, could lead to an unexpected reduction in the number of individuals of a
species under apparent conditions of abundant food.
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REFERENCES
Baker-Dittus, A.M. 1978. Foraging patterns of three sympatric killifish. Copeia, 1978(3):
383-389.
Burell, K.L. 1992. Comparing dietary niche between two species of Cyrprinidae through
the use of an overlap index. Bios, 63(2): 21-27.
Cardona, L. 1991. Measurement of trophic niche breadth using occurrence frequencies.
J.FishBiol.,39.90\-9Q3.
Gladfelter, W.B. and W.S. Johnson. 1983. Feeding niche separation in a guild of tropical
' reef fish (Holocentridae). Ecology, 64: 552-5563
Keast, A. 1978. Feeding interrelations between age-groups of pumpkinseed (Lepomis
gibbosus) and comparisons with bluegill (L. macrochirus). J. Fish. Res. Bd. Canada,
35(l):12-27.
Schoener, T.W. 1970. Non-synchronous spatial overlap of lizards in patchy habitats.
Ecology, 51:408-418.
Yap, S-Y. 1988. Food resource partitioning of fifteen fish species at Bukit Merah
Reservoir, Malaysia. Hydrobiologia, 157(2): 143-160.
215
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TABLE 1. Proportion of total diet by frequency of occurrence.
Proportion of total diet*
Food Category
1 . Horsehoe crab larvae
2. Horseshoe crab eggs
3. Molluscs
Clams, Mercenaria spp.
Ribbed mussels
F. heteroclitus
0.9885
0.0000
0.0000
F. majalis
0.5462
0.1209
0.2966
0.2921
0.0045
4. Small Crustaceans 0.0023 0.0036
Grass shrimp 0.0004 0,0036
Crab larvae 0.0004 0.0000
Amphipod 0.0015 0.0000
5. Annelids (Opal worms)
6. Fish eggs
7. Fish larvae
8. Fish
0.0004
0.0078
0.0007
0.0004
0.0027
0.0285
0.0014
0.0000
""Overlap coefficient (O) = 0.56.
216
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TABLE 2. Proportion of total diet by weight.
Proportion of total diet*
Food Category F.heteroclitus F. majalis
1 . Horsehoe crab larvae
2. Horseshoe crab eggs
3. Molluscs
Clams, Mercenaria spp.
Ribbed mussels
0.7582
0.0000
0.0000
0.3988
0.1005
0.1759
0.1713
0.0046
4. Small Crustaceans 0.0182 0.0525
Grass shrimp 0.0109 0.0525
Crab larvae 0.0052 0.0000
Amphipod 0.0021 0.0000
5. Annelids (Opal worms)
6. Fish eggs
7. Fish larvae
8. Fish
0.0104
0.0233
0.0052
0.0036
0.0151
0.0155
0.0046
0.0000
*Overlap coefficient (O) = 0.66.
217
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K)
>—*
00
2
o>
.Q
40 n
30-
20-
10-
D Mummichog
E3 Striped
5.0-5.5 5.6-6.0 6.1-6.5 6.6-7.0 7.1-7.5 7.6-8.0 8.1-8.5 8.6-9.0 9.1-9.5 9.6-10.0
Length Categories (cm)
Figure 1. Frequency distributions of numbers of mummichog and striped killifish for different ranges of standard length.
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EASTERN SHORE OF VIRGINIA WATER QUALITY CONSORTIUM
Terry Thompson
The Nature Conservancy's Virginia Coast Reserve
P.O. Box 158
Nassawadox, VA 23413
HISTORY
The Water Quality Consortium has served since 1992 as an informal forum to support
development of new water quality monitoring and stewardship projects on the Eastern Shore of
Virginia. At the time of its formation, there were many groups and agencies involved in some
aspect of water quality protection and monitoring on the Virginia Eastern Shore. However,
because these efforts were uncoordinated, the potential fell short of the sum of the parts.
One group had just completed a year-long, multi-phase and volunteer-based water quality
monitoring project (Lagera, 1992). This collaborative project with Citizen's for a Better Eastern
Shore, Eastern Shore Working Watermen's Association, Department of Environmental Sciences
University of Virginia, Virginia Coast Reserve, Virginia Environmental Endowment, and
Northampton County Board of Supervisors developed out of a concern for determining the status
of water quality in the county's creeks. This project established needed baseline information and
found that, in general, water quality conditions in Northampton's creeks were good. However,
the value of the project went beyond providing documented and tangible information to illustrate
the good quality of the nearshore waters. It also spurred the interest and concern of the
community and local government. There was a desire to continue the development of a network
of concerned individuals focused on water quality-related projects.
With the support of some initial funding from an EPA Near Coastal Waters program
grant, the Water Quality Consortium began meeting every other month to build upon the initial
interests and to involve other interested individuals and research scientists, enhancing the current
and future body of knowledge about water quality conditions on the Shore. The Consortium
serves as a information exchange and networking vehicle among researchers, citizens,
conservation organizations, businesses, professionals from local, state and federal agencies, and
educators. The Consortium operates by concensus and new members are invited by
recommendation of current participants. The meetings have included invited speakers and field
trips related to on-going water quality projects on the Eastern Shore.
While the Water Quality Consortium does not do all of the actual work to accomplish
specific water quality initiatives, this group does function to facilitate and support the work of
individual members and the diverse groups they represent. The Citizens for a Better Eastern
Shore designated the Water Quality Consortium as one of the "Best Cooperative Partnerships" for
1993. While the initial funding is gone, the Consortium continues to function as a valuable
networking and information forum with in-kind support and lots of personal committment from its
members.
DESCRIPTION OF AREA
The Eastern Shore of Virginia is a narrow peninsula of land bounded by the Chesapeake
Bay and the Atlantic Ocean and composed of 2 counties, Accomack and Northampton. Just off
the seaside of the mainland peninsula lies the last intact, naturally functioning coastal barrier island
ecosystem on the Atlantic Coast. This ecological treasure consists of a chain of barrier islands, 14
of which are the core preserve in the Nature Conservancy's Virginia Coast Reserve. The Reserve
is a barrier island wilderness area containing some 45,000 acres of sandy beaches, salt marsh, and
adjacent upland along the Eastern Shore of Virginia. The coastal bays and wetlands between the
barrier islands and the mainland forms a barrier island lagoon ecosystem which serves as an
extremely rich spawning and nursery ground for finfish and shellfish. There is no major fresh
water river input into the saline lagoon system, nor the often associated pollution problems carried
from a distance The waterfront consists of mainland marsh fringe, seaside farms with natural
wooded buffers, bottom-land hardwood corridors, small residential settlements, and seaside
villages.
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Route 13 is the dividing line for seaside and bayside watersheds. The groundwater
recharge for a sole source aquifer occurs along the spine of the peninsula, which closely
approximates the path of Route 13. The bayside watershed consists of many creeks which divide
the shore into necks of land with small residential settlements and agricultural/forestral areas.
These creeks empty into the brackish Chesapeake Bay estuary.
Water quality and quantity concerns for the surface and ground water resources on the
Eastern Shore of Virginia are tied closely to the historical and economic dependence of the
community on its unique natural resources. The Shore has a long history of low-impact human
uses of these natural resources with fishing and seafood harvesting and a hope for better
economic future with aquaculture opportunities.
BENEFITS OF THE WATER QUALITY CONSORTIUM
The benefits of the consortium include: coordination of efforts and protocols, thereby
reducing redundancy and adding value to everyone's data; formal sharing of data and other
information; determination of high priority needs for additional monitoring and research; and
encouragement and support for water quality-related projects.
While an initial joint project to assess the water quality of bayside and seaside creeks on
the Shore found that the -water quality was pretty good, the results did identify some areas of
specific concern: some creeks with seasonal or event associated elevated nutrient levels,
upstream creek areas with low DO conditions, and closure of areas to shellfish harvesting because
of elevated fecal colifbrm. As a result, some groups have moved beyond monitoririg and begun to
focus on mitigation. This has been possible by involving citizen monitoring to identify "hot spots"
while researchers give guidance and quality assurance, then sharing the results cooperatively with
regulatory agencies and businesses to begin to find solutions to the identified problem areas.
The benefits of supporting and-working with citizen initiated monitoring programs goes
beyond the information gained. These groups have been able to get stakeholder involvement and
adjacent landowners' support, improving access for sampling and generating grass-roots financial
support. Some of these volunteer citizens have demonstrated a willingness (which exceeds many
graduate students' committments) to conduct 24-hour sampling sessions with the guidance of
researchers to get the information they need. These citizens are then able and willing to speak
with first-hand knowledge to inform others and advocate support from local government.
The Water Quality Consortium continues to serve as a valuable information and education
network, including updates on on-going projects by researchers and citizens. The group meetings
and distribution of notes from meetings serves as a vehicle to share access to new resources in a
timely and comprehensive manner. While some research projects are collecting data to answer
specific scientific questions, these researchers are participating and sharing their results so that
this information may also be used to address other broader concerns for water quality and provide
applied research results to support aquaculture or other water-related issues.
Several research projects which are being shared within the Water Quality Consortium
have potential to demonstrate water resource management alternatives. The. Green's Creek
Watershed project has developed as a cooperative applied research project involving the farmer,
agricultural researchers, hydrologist, geologist, biologist, chemist, and conservationists.
Subsurface transport research may provide applied information for impact of septic systems, with
recommendations for local spacing and set-backs. Many researchers are working with mapping
(GIS & GPS) information which, when shared with the county government and other resource
and conservation agencies, can potentially provide overlays for management decisions.
Water Quality is related to the Shore's move toward a sustainable economy and quality of
life issues for all residents. Recent research coordinated with citizen groups has discovered that
shellfish areas, which were closed due to fecal coliform contamination, may be related to wildlife,
specifially scat from large populations of raccoons. Creative mitigation projects have been
successful in advancing the re-opening of some of these shellfish harvest areas. A seaside village
community has recently completed a visioning/planning process to examine opportunities and
concerns for the future of their community and the potential for sustainable development. This
has included research which provided an analysis of wastewater needs and options for alternatives
specific to the environmental conditions and sustainable development vision of the community.
220
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Alternative wastewater has also been incorporated into plans for an affordable housing project in
another village.
The community has initiated EPA to indentify the shore as a sole source aquifer. A citizen
group believes that some shore waterways should be designated under EPA Tier III exceptional
waters. Another citizens group is using Water Quality Consortium members on a technical
advisory committee for their EPA 319 nonpoint source pollution proposal. Partnerships are a
valuable resource and the networking which occurs in the Water Quality Consortium's informal
forum allows individuals to come with questions and get ideas in a cooperative, non-adversarial
atmosphere. Information and involvement can lead to empowerment. Citizen involvement with
researchers has shown that scientific data can be a powerful tool, but with it comes responsibility.
Many Water Quality Consortium members have commented that they believe some of these
projects would not have started without the interactions and support of the group.
APPENDIX: THE WATER QUALITY CONSORTIUM - MISSION & GOALS
The Water Quality Consortium is working to protect and enhance the quality of Eastern
Shore coastal bays, creeks and groundwater. Our general purpose is to determine the extent and
quality of the resource and the demands and threats to the resource, and to develop management
alternatives.
GOAL 1 CONDUCT CREDIBLE WATER QUALITY MONITORING
Activities and Actions:
A. Ensure that all research performed meets the highest quality standards.
B. Develop local leadership that is knowledgeable about the extent and quality of our
waters and the demands and threats on this resource.
C. Establish pilot long-term monitoring programs.
GOAL 2. PROVIDE INFORMATION/EDUCATION NETWORK FOR ALL INTERESTED
PARTIES
Activities and Actions:
A. Facilitate the review and interpretation of research results into layman's summaries
for public understanding and support of on-going initiatives.
B. Provide institutional/educational opportunities for interested students, citizens and
water quality researchers and professionals.
C. Have an accessible repository on the Eastern Shore for pertinent information,
regulations, and educational materials.
D. Maintain a summary of regulatory activities.
GOAL 3. IDENTIFY & ESTABLISH PRIORITIES FOR WATER RELATED ISSUES AND
PROVIDE SUPPORT AND COORDINATION TO GUIDE RESEARCH
DIRECTION
Activities and Actions:
A. Facilitate and encourage research initiatives for high-priority mainland tidal creeks.
B. Identify research funding sources.
GOAL 4 IDENTIFY & DEMONSTRATE WATER RESOURCE MANAGEMENT
ALTERNATIVES
Activities and Actions:
A. Encourage development of economically sound management alternatives.
B. Support the implementation of a management plan for specific demonstration sites.
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G. Monitor results of the management plan and provide results to all interested
parties.
References
Lagera, L.M. 1992. A study of Water Quality Conditions in tidal creeks of Northampton
County. Northampton County Water Quality Monitoring Project. Eastville, VA.
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DOCKS AS SHALLOW WATER REFUGE FOR JUVENILE BLUE CRABS
Jason D. Toft, Anson H. Hines, and Greg M. Ruiz
Smithsonian Environmental Research Center
P O. Box 28
Edgewater, MD 21037
INTRODUCTION
Docks for recreational boats are abundant structures in shoreline habitats of many aquatic
systems but their relative impact on community dynamics is unknown. Certain features of docks
are often considered to impact the environment negatively, such as associated habitat disturbance
and input of pollution. However, the physical structure of docks may also serve as an important
artificial habitat in the nearshore zone. Natural structure such as submerged aquatic vegetation
(SAV) (Heck & Thoman, 1981), coarse woody debris (CWD) (Everett & Ruiz, 1993), and
shallow water habitat (Ruiz et al., 1993) has been shown to have important nursery functions
providing juvenile fish and
crustaceans with refuges from predation Since docks provide significant structure located in the
shallow water zone, docks may serve as an important component of nursery habitats.
Docks are unique in that they are a recent artificial addition to the shoreline habitats of
many aquatic systems. In estuaries such as the Chesapeake Bay, the abundance of docks has
increased significantly during the past 50 years (Figure 1), the same time period in which other,
natural structure (SAV, oyster reefs, CWD) has decreased markedly in the estuary (Orth &
Moore, 1984; Rothschild et al. 1994; Everett & Ruiz, 1993). If juvenile organisms are using
docks as refuges from predation, it would illustrate the ability of these organisms to adapt to the
changing environment by making use of alternate habitats with the decline of natural refuge
habitats.
In this study, we use descriptive sampling and field experiments to quantify the refuge
value of habitat underneath docks compared to adjacent habitat. Specifically, the following
hypotheses are tested: (1) Docks provide a refuge habitat for juvenile organisms in estuarine
communities; (2) Both the physical structure of docks and the shading effect of docks contribute
to refuge value, and (3) Distribution and abundance patterns offish and crabs reflect the beneficial
habitat underneath docks compared to adjacent habitat. The blue crab Callmectes sapidus was
chosen as a model species due to its large abundance and range in estuaries of Eastern North
America as well as its importance in the fisheries industry.
METHODS
Study Sites
Three dock sites located in the upper Rhode River, a subestuary of central Chesapeake
Bay, were used in the study. The docks were specifically chosen to represent three different size
classes of docks as well as three different degrees of human usage and boat traffic. Site A had a
large dock (surface area = 300 m2) with a high amount of usage; Site B had a medium dock
(SA=87.8 m2) with an average amount of usage; and Site C had a smaller dock (SA=63.6 m2)
with a low amount of usage. Shoreline surrounding the docks consisted of natural habitat,
including sandy beach, marsh vegetation, and woody debris. None of the study sites contained
non-dock physical structure in the immediate vicinity of the experiments.
Field Predation Experiments
In order to compare relative rates of predation between underneath docks and adjacent
habitat, we utilized tethering techniques on juvenile blue crabs. Laboratory experiments on
tethered blue crabs have shown that the crabs remain healthy and do not escape during the length
of the experimental prodedure (Ruiz et al., 1993). We also observed in the laboratory the
behavior of a tethered blue crab when confronted with a larger predatory blue crab, and found
that the tethered crab could successfully perform escape behaviors. This is significant in that
cannibalism accounts for around 90% of crab predation in the Rhode River (Ruiz et al., 1993).
Tethering experiments were performed at the dock sites during July and August 1994.
Juvenile blue crabs were collected from Chesapeake Bay and either used the day of collection or
223
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maintained for a short term in tanks until the day of the experiment. Crabs were restricted to
intermolt individuals with a carapace width of 30-70 mm in order to control for differences in
behavior patterns and predation risk. A loop of monofilament line (9.07 kg test) was tied around
the crabs' antero-lateral spines in order to form a harness. One end of a 0.75 m nylon coated steel
wire (4.54 kg test) was then tied to the harness, with the other end of the wire attached to a steel
spike. A few drops of cyanoacrylate glue were added to the knots in order to secure the .harness,
and each crab was kept in a small cup of water until deployment. At the field site, the spike was
shoved vertically into the sediment, allowing the crab a 0.75 m radius circle of movement.
Four crabs were deployed both underneath the dock and 10m adjacent to the dock at
each site for each repetition, with a total of six repetitions. The crabs were placed in a square 1.5
m apart from each other to ensure that the tethers would not get tangled, with the shore side of
the square 7 m from mean high tide. Crabs tethered underneath docks were positioned so that
they could have access to a dock piling. Crabs were checked after 24 hours for signs of
predation, and recorded as either present (no predation), absent (predation), or present with
missing limbs and/or puncture wounds (predation).
In order to manipulate the affect that piling structure and shading of docks has on refuge
value, another tethering experiment was performed on constructed model docks. Piling structure
was represented by 10 X 10 X 100 cm wood posts, and shade was represented by 40 X 150 cm
plywood. The experimental design consisted of four plots: (1) piling structure with shade; (2)
piling structure without shade; (3) shade without piling structure; and (4) control plot with no
artificial structure. In plot (3) testing for shade, the plywood was elevated by 1 X 1 cm
reinforcement bar. Each plot had an area of 40 X 150 cm, and three repetitions of each plot were
constructed and deployed parallel to shore in alternating treatments 7 m from mean high tide, with
5 m separating each treatment. Tethering experiments were performed at the model dock sites
during September, using the same techniques as the dock tethering experiment. Crab tethering
was initiated within a week after the structures were constructed, so that a residual community
and encrusting organisms would not develop by certain structures. Such a design allowed the
effects of structure and shade to be tested without the influence of nutritional factors and
distributional patterns of background organisms.
Distribution and Abundance Patterns
Seine net samples were taken in order to quantify the species and number of organisms
associated with dock habitats compared to adjacent habitats. The net (3.3 m mouth opening, 4
mm mesh) was pulled perpendicular to shore starting 20 m out from mean high tide, all organisms
captured were identified to species, and the first twenty individuals of each species were
measured. Three seine samples were collected from both underneath the dock and 10m adjacent
to the dock at each site.
RESULTS
Tethering Experiments
Predation rates beneath docks were significantly less than adjacent habitat when the data
was pooled among all three sites (df=l, value=4.73, p < 0.03). Predation rates were also
significantly different between the three sites (df=2, value=9.39, p < .01), but were not significant
in site X treatment (df=2, p > .8). Figure 2 illustrates the differences in predation rates by both
treatment and site, and also shows that the trend in predation rates for the sites correlates to the
gradient in size and human usage of the docks — as size of the dock and amount of dock usage
increases, predation rates decrease. Predation rates at the experimental structures mimicked the
dock experiment and also illustrate that both structure and shade contribute equally to the
decrease in predation rates underneath docks (Figure 3). Predation rates were significant among
all treatments (df=3, value=l 1.22, p < .02) and were especially significant between the structure
and shade versus the control treatments (df=l, value=l 1.05, p < .002).
Distribution and Abundance Patterns
The majority of species captured by seine netting were more abundant underneath docks
compared to adjacent habitat (Figure 4). Juvenile white perch (Morone americand),
mummichogs (Fundulus heteroclitus), blue crabs (Callinectes sapidus), striped bass (Morone
224
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saxatilis), and brown bullhead (Ictalurus nebulosus) were more associated with the dock
environment while juvenile Atlantic silversides (Menidia spp.), banded killifish (Fundulus
majalis), and menhaden (Brevoortia tyrannus) were more associated with adjacent habitat.
DISCUSSION
Recreational docks are rapidly becoming a major shoreline component in many aquatic
systems, and most environmentalists may initially consider the construction of docks as bad for
the surrounding natural community. Increased dock construction and usage means more human
land and water activities which are usually associated with a decrease in natural habitat and an
increase in pollutants. However, our results show that dock habitats do have a beneficial function
in estuarine communities, albeit due to the concurrent decline of natural refuges from predation.
Docks are also unique from natural structures in that docks are not only connected to the
shoreline but extend perpendicular to the shore both in and above the water column. This is
important in that both the physical structure of dock pilings in the water as well as the shading
aspect of the above planks provide a refuge from predation for juvenile organisms. Size of dock
and amount of human usage affect the refuge value of specific docks. Size may be important in
that the larger the dock, the more physical structure and shaded area available for refuge.
Increased human activities may affect predation rates due to disturbance in the water column from
associated water activities such as boat traffic.
Dock habitats also host a different community than adacent habitat as there are more
juvenile fish and crabs underneath docks. Our data supports the hypothesis that these juvenile
organisms prefer dock habitats mainly due to the refuge value, making docks important nursery
habitats.
The success of the model dock experiment further proves the refuge value of docks and
disproves an alternate hypothesis that predation rates were lower underneath docks due to a
artifact from the higher abundance of background organisms, which could be there for only
nutritional or other reasons. The experiment was initiated within a week after the miniature docks
were constructed which is not enough time to develop beneficial nutritional characteristics or a
high background density of organisms. The model dock experiment also illustrates that random
abandoned pilings in the water column can provide a refuge from predation, as indicated by the
decreased predation rates at the plots consisting of pilings without shade.
It is important to investigate whether the introduction of artificial structures into natural
habitats has purely negative effects or if organisms can adapt to the change in their environment
and beneficially utilize introduced components into their habitat at the expense of the loss of
original components. Such adaptation can be seen in some cases with human modification of land
habitats, such as the thriving populations of pigeons and rats in cities. Examples are less obvious
in aquatic environments but are equally important. At the current rate of human modification of
natural habitats, utilization of artificial structure may be crucial in preserving animal biodiversity.
LITERATURE CITED
Heck, K. L. Jr, Thoman, T. A. (1981). Experiments on predator-prey interactions in
vegetated aquatic habitats. J. exp. mar. Biol. Ecol. 53:125-134.
Orth, R. J., Moore, K. A. (1984). Distribution and abundance of submerged aquatic
vegetation in Chesapeake Bay: a historical perspective. Estuaries 7:531-540.
Everett, R. A., Ruiz, G. M. (1993). Coarse woody debris as a refuge from predation in
aquatic communities. Oecologia 93:475-486.
Ruiz, G. M., Hines, A. H., Posey, M. H. (1993). Shallow water as a refuge habitat for fish
and crustaceans in non-vegetated estuaries: an example from Chesapeake Bay. Mar.
Ecol. Prog. Ser. 99:1-16.
Rothschild, B. J., Ault, J. S., Goulletquer, P., Heral, M. (1994). Decline of the
Chesapeake Bay Oyster population: a century of habitat destruction and overfishing.
Mar. Ecol. Prog. Ser. 111:29-39.
225
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250 -,
ce
a
«s
a
9
z
200
150
100
50
0
1930 1940 1950 1960 1970 1980 1990 2000
Year
Fig. 1. Increase in the number of docks in the Rhode River, a subestuary of
Chesapeake Bay, during the past 50 years.
226
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80-i
60-
o
ea
•0 40-
4)
Pu
^
20-
A-
•XvX
X'X'I*
:x-x-:
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•"•*•*•*•*
Dock
Adjacent Habitat
Small
Medium
Large
Fig. 2. Average percent predation of juvenile blue crabs underneath docks
versus adjacent habitat for Small (Site C), Medium (Site B), and Large (Site
A) docks.
227
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I
CO
\\ \\
Fig. 3. Average percent predation of juvenile
blue crabs at the model dock structures.
228
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125 -,
Dock
Adjacent Habitat
Fig. 4. Distribution and abundance of species captured by seine netting at dock habitats and
adjacent habitat
229
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IMPACTS ON THE MARINE ENVIRONMENT FROM THE SHADOWS OF HIGH-
RISE TOWERS AND OTHER STRUCTURES
Michael P Weinstein
TEVA Environmental Associates, Inc.
854 Ridgewood Road
Millburn, New Jersey 07041
ABSTRACT
Light attenuation measurements were taken within the shadow and in ambient areas below
a 33-story high-rise structure and 6.1 m and 30.5 m below the roadway of a major suspension
bridge located in metropolitan New York in order to quantify the effects of large structures on
light intensities beneath them (i.e., the shadow effect). The application of these measurements to
published P-I curves and solar angle-hydrodynamics driven exposure frequencies for marine
phytoplankton and algae demonstrated that the reductions in ambient light from shadows cast by
similar structures including platforms located over the water will have little or no effect on the
productivity of marine plants in the nearshore zone.
INTRODUCTION
Regulatory attention has often focused on the affects of shading on marine organisms
resulting from the construction of large waterfront projects. For plants, these affects may include
reductions in primary productivity, inhibition of vegetative and reproductive growth, and
reduction in population density and community diversity. In this study, we use existing literature
and field measurements on light attenuation in shadows to evaluate the potential impacts of
shading by human-made structures on marine plants.
METHODS
Two structures, high-rise buildings and a bridge roadway, were evaluated to estimate the
attenuation of light that would result from shadows cast by similar structures at a proposed
waterfront project in western Long Island Sound. Measurements were taken below a 33-story
residential building located in the Bronx, New York. The height of this structure was estimated
to be 125 m. We selected an isolated building that was not influenced by shadows from nearby
adjacent structures and that faced a water body, in this case the Hutchinson River. Light
measurements were taken on a bright hazy day at approximately 0900, 1200, and 1500 hours on
July 29, 1988. Other relevant weather conditions at 1410 on the day of the measurements
include: bright sunshine (approximately 50 Klux at noon), an air temperature of about 31 C, and
a relative humidity of 56%.
The nearshore portion of the Whitestone Bridge was used to represent the shading effects
that would be produced by the construction of a bridge to a project site (an island about 1200 m
from the mainland). Light readings were taken at two roadway heights below the bridge, about
6.1 m and 30.5 m from ground level. These locations represented the height of the proposed
bridge above the intertidal zone and the approximate high point (about 22 m) of the bridge above
the water.
Light measurements were taken with a Spanta Inc. Model LX-01 irradiation sensor with a
sensitivity range of 0 to 200 kilolux and a resolution of 100 lux, attached to a Model 96 digital
multi-meter. To convert lux into quanta, the following conversion was applied:
1 kilolux = 6.022 * 1013 quanta sec^cm'2
RESULTS
Building Shadows
Light readings taken inside and outside of the building shadow ranged from 40.1 Klux to
51.0 Klux (Table 1). The percent of ambient light in the shaded areas ranged from 78.9% to
96.1% with a mean of 90.9 ± 5.5% SD (n=9). Comparisons of the 0900, 1200 and 1500 h light
readings within and outside of the shadows showed a uniform light reduction of approximately
12% and 5% at 0900 and 1200, respectively, while at 1500 reductions ranged from 4% to 21%.
230
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The apparently aberrant middle outside shadow reading at 1500 (Table 1) may be the result of
changing haze conditions.
It is, of course, no surprise that light readings taken at approximately one meter intervals
along a cross section of the middle of the building shadow indicate that the amount of light
decreases slightly when moving in toward the centerline of the building and increases toward the
edges of the shadow. Similarly, as one moves outward along the long axis of the shadow, the
difference between the middle and the edge of the shadow decreases.
Seven Meters Below the Roadway
Light readings taken at the midpoint of the shadow 6.1 m below the roadway were the
lowest readings recorded at the Whitestone Bridge, ranging from 23.5 Klux to 28.8 Klux (Table
1). This resulted in a mean light reductions of 49.0 ± 6.5% SD (n=3) based on the 0945, 1245,
and 1530 h readings. However, it should also be noted that no point remains in the center of the
shadow for too long. For example, from 1240 to 1530 h the shadow moved 8 m to the west.
Shadow width increased during this same period from about 20 m to 24 m. The readings at the
edge of the shadow, which ranged from 44.3 to 47.9 Klux, showed a mean reduction of only
8.3% ± 2.2% SD (n=3) of ambient light.
Thirty Meters Below the Roadway
Compared to areas outside the shadow, readings taken 30.5 m below the bridge exhibited
only slight reductions in the amount of light present (Table 1). Mean light reductions were 3.3%
± 4.4% SD (n=3), 4.7% ± 0.6% SD (n=3), and 4.9% ± 0.8% SD (n=3) for the western shadow
edge, midpoint of shadow, and eastern shadow edge, respectively. In addition, the intensity of the
shadow cast 30 m below the bridge at about 1545 h decreased as one moved away from the base
of the shadow, at the edge only 0.4% of ambient light was being blocked by the bridge.
DISCUSSION
Under the conditions of our study, we were able to quantify the intensity of light at
various points inside and outside of shadows cast by a tall building arid the roadway of a bridge.
In all cases, except for the midpoint of the shadow 6.1 m under the Whitestone Bridge, there did
not appear to be any substantial reduction of light.
To estimate the magnitude of reductions in photosynthetic performance of marine plants
that might be expected from the construction of high-rise residences and the bridge to the island,
the range of light intensities recorded during this study were plotted onto curves derived from the
published literature relating photosynthetic activity to quantity of illumination. The rate of
photosynthesis is a linear function of light intensity over a certain range of low to intermediate
intensities, but is essentially independent of light intensity over a second range of intermediate to
high intensities (which support maximal rates of photosynthesis), and can be photo inhibited at
high light intensities (Peterson et aL, 1987). Marra (1978) also noted that phytoplankton studied
in Nova Scotia reached a light saturated photosynthetic rate at approximately 25 Klux, about 30%
of the total irradiance of noon sunlight on a spring day in Nova Scotia. An asymptotic
relationship between photosynthesis and irradiance was also observed by Harding et al. (1981).
Peterson et al. (1987) published curves establishing an empirical relationship between light
intensity and photosynthetic activity for in situ experiments conducted on natural assemblages of
the phytoplankton in San Francisco Bay. Potential shading effects on the photosynthetic
performance of the phytoplankton studied by Peterson et al. were estimated for this study by
pairing ambient light readings with maximum light reductions recorded in shadows in our study,
and fitting them onto the curves from Peterson et al. (Figure 1). These data were selected
because they represent much of the range of light intensities recorded in the shadows and nearby
areas, and in the case of the shadow cast by the roadway of the Whitestone bridge represent a
worst-case scenario.
Although we believe that this relatively simple approach is valid for purposes of assessing
the potential effects of shadows cast by large structures on the photosynthetic performance of
marine phytoplankton, it should be recognized that:
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• The parameters of the light-saturation (P-I) curves are not always constant, rather the
slope (a) and the asymptote (P^ vary somewhat with time (seasonal and diel), depth,
and both within and among species.
• Light readings recorded in this study were taken above the waters surface and therefore
did not take into account natural factors present in the water column such as turbidity that
would tend to reduce light intensity with depth. This reduction (or attenuation) continues
at a rather constant rate with equal increments of depth. This relationship also assumes
that impurities in the water column are relatively uniformly distributed, a condition that
may not always be the case in estuaries.
The plots of light intensities for the building shadows taken at about 1530 h show that the
minimum value recorded within the shadow fell within the portion of the P-I curve where the
maximum photosynthetic performance could be maintained (Figure 1). Had the individual
readings taken at about 0900 and noon (Table 1) been plotted onto the curves, the results would
have been the same; i.e., no significant adverse impact on photosynthetic performance would have
occurred. The upper limit of light readings taken in the shadow 6.1 m below the bridge also fell
within the maximum photosynthetic performance range of the curve throughout the day (morning
data are not shown on the plots), however, the lower limits of each range were approximately 5%
to 10% below maximum photosynthetic performance levels. Thus, under the conditions
investigated here, photosynthetic performance of phytoplankton exposed to maximum light
reduction within shadows would not be expected to differ greatly from photosynthetic
performance or organisms in ambient light. Curves derived by Peterson et al. (1987) also
demonstrate that at the highest intensities observed, slight effects of light inhibition would be
expected.
The range of ambient and shadow values were also plotted on productivity versus light
intensity curves for sun-adapted and shade-adapted algae (Figure 2) derived from data collected
by Meyers and Graham (1971). Meyers and Graham grew algal cultures (Chlorella pyrenoidosd)
at six different light intensities in the laboratory to study the productivity versus light intensity
relationship. When light readings taken below the high-rise building and 6.1 m below the bridge
were fitted to the curve derived for sun-adapted algae, they generally fell close to the maximum
photosynthetic capacity (Figure 2). However, the expected photosynthetic performance of algae
exposed to the minimum light intensity reading from 6.1m below the bridge fell approximately
20% to 25% below maximum. On the other hand, all light intensity readings for the high-rise
building and 6.1m below the Whitestone Bridge fell within the maximum productivity portion of
the curve for shade-adapted algae (Figure 2).
SUMMARY AND CONCLUSIONS
Other studies support the conclusion that photosynthetic performance of marine plants in
the shore zone or in the water column will not be greatly affected by shadows cast by large
structures of the sort investigated here (high-rise buildings and bridges). Kearney et al.
(unpublished results) studied the effects of docks on salt marsh vegetation in Connecticut. They
compared vegetation density and height beneath and adjacent to these structures and used them as
indices of vegetative change. Their plot of vegetation height versus dock height interval for
smooth cordgrass, Spartina alterniflora is reproduced as Figure 3. The effects of shading
decreased markedly after approximately 70 cm and dock height above 480 cm appears to produce
little or no effect on vegetation height. Moreton (unpublished manuscript) photographed
intertidal grasses below piers, ranging from about one to 1.5 m above the surface of sand or mud
and approximately 1.2 m wide, in Cape Cod, MA. He noted grasses growing "abundantly" and
"luxuriantly" under tall piers and concluded that direct sunlight at various times during the day
together with indirect sunlight for most of the day are apparently more than adequate to maintain
intertidal grasses.
This raises another point about shadows; they are not static entities but move in concert
with the orbit of the earth around the sun. Therefore, despite the reduction of light, the shadow
effect should only last for a short period at a given locus. Moreover, the range of tidal flow
would quickly pass through the shadow. To estimate this period, the assumption was made that
the shadow cast by each high-rise residential unit was roughly equivalent to the width of each
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unit. The latter dimension was chosen because prevailing currents in the near-shore area would
generally occur at near right angles to shadows emanating from the shoreline. At an average
measure tidal velocity of 0.1 m sec'1, the estimated time of transit across the 30 m wide shadow
of a high-rise residential unit near noon would be about 5.4 minutes. This estimate is also
conservative because for most of the year with the exception of winter, shadows cast by high-rise
buildings would be frequently confined to land portions of the shoreline, rather than being cast
upon the waters of Long Island Sound.
In conclusion, previous research and our studies described herein, indicate that the shading
impacts of large structures of the type proposed for this project should have little or no impact on
intertidal or marine plants in the vicinity.
REFERENCES
Harding, L.W. Jr., B.W. Meeson, B.B. Prezelin and B. M. Sweeney: 1981. Diel
periodicity of photosynthesis in marine phytoplankton. Mar. Biol. 61: 95-105
Marra, J. 1978. Phytoplankton photosynthetic response to vertical movement in a mixed
layer. Mar. Biol. 46: 203-208.
Meyers, J. and J.R. Graham. 1971. The photosynthetic unit in Chlorella pyrenoidosa
measured by repetitive short flashes. Plant Physiol. 48: 282-286.
Peterson, D.H., M.J. Perry, K.E. Bencala, and M.C. Talbot. 1987. Phytoplankton
productivity in relation to light intensity: a simple equation. Estuar. Coast. Shelf
Sci. 24: 813-832.
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Table 1. Light readings from sampling points on 29 July 1988. Percentages of ambient light
detected in approximate mid-point of shadowed areas are noted in parentheses.
Location
High Rise Building
Beginning of
Shadow
Outside Beginning
of Shadow
Middle of Shadow
Outside Middle
of Shadow
Apex of Shadow
Outside Apex
of Shadow
Whitestone Bridge
Readings approximately
Midpoint of Shadow
Outside Midpoint
of Shadow
Edge of Shadow
Outside Edge
of Shadow
Readings approximately
Western Edge
of Shadow
Outside Western
Edge of Shadow
Morning (Time)
Reading (Klux)
0857
42.1 (87.0)
0900
48.4
0905
43.0(88.7)
0905
48.5
0910
43.5 (90.0)
0912
48.3
6. 1 m below bridge
0945
28.8 (53.3)
0940
49.4
0946
44.3 (89.7)
0947
49.4
30.5 m below bridge
0954
45.0 (98.9)
0955
45.5
Noon (Time)
Reading (Klux)
1155
45.3 (94.8)
1152
47.8
1157
48.2 (94.7)
1156
50.9
1158
47.8 (95.4)
1159
50.1
1240
23.5(46.1)
1243
51.0
1241
46.3(91.3)
1242
50.7
1231
46.9(91.6)
1230
51.2
Afternoon (Time)
Reading (Klux)
1510
40.1(78.9)
1500
50.8
1503
44.7(96.1)
1505
46.5
1515
47.1 (92.4)
1518
51.0
1530
24.7 (48.5)
1529
50.9
1533
47.9(94.1)
1529
50.9
1548
49.8 (99.6)
1549
50.0
234
-------
Table 1. (Continued). Light readings from sampling points 29 July 1988. Percentages of
outside light detected in shadowed areas are noted in parentheses.
Morning (Time) Noon (Time) Afternoon (Time)
Location Reading (Klux) Reading (Klux) Reading (Klux)
Readings approximately 30.5 m below bridge
Midpoint of shadow 0955 1232 1547
46.6 (95.1) 45.5 (94.8) 47.2 (95.9)
Outside Midpoint 0956 1235 1550
of Shadow 49.0 48.0 49.2
Eastern Edge 0957 1233 1546
of shadow 48.2(95.6) 47.3(95.6) 45.3(94.2)
Outside Eastern 0958 1234 1554
Edge of Shadow 50.4 49.5 48.1
235
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INCUBATION TIME
HI
o
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O
O
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DAYLIGHT
17
51
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LIGHT INTENSITY
24 HOURS
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0
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0.6
0.4
0.2
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H
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246
10l6quanta cm"2*"1
17
51
34
Kilolux
LIGHT INTENSITY
TIME: 1200 HOURS
KEY: O WHITESTONE 100 FEET
A WHITESTONE 20 FEET
O CO-OP CITY
O AMBIENT LIGHT
01
CD
X
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m
-------
500
400 HlHJi." Si 5f it?
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Kilolux
LIGHT
INTENSITY
KEY:
O WHITESTONE 100 FEET
£ WHITESTONE 20 FEET
O CO-OP CITY
O AMBIENT LIGHT
TIME: 1500 HOURS
Figure 2. The affect of light reduction in shadows on photosynthetic performance for sun-
and shade-adapted algae. Curves were drawn from data collected by Myers and Graham
(1971). Minimum and maximum readings taken at about noon and 1500 hours at each site
were plotted onto curves.
237
-------
1.2
1.0
X
3
z
0.8
S
I
0.6
00
0.4
0.2
O
INTERVALS
1=0-30cm 6=151-180cm
2=31-6Qcm
3=61-90cm
4=91-120cm
5=121-150cm
7=181-210cm
8=211-240cm
9=241-270cm
10=271-300cm
5678
DOCK HEIGHT INTERVAL
10
Figure 3. Vegetation height index of the marsh grass Spartina alterniflora plotted against dock height interval (unpublished data
from Kearney et al.)
-------
DUNE PROTECTION AND REPLENISHMENT: THE ANDRES METHOD
Stan G. Andres
The Mens Garden Club of Long Beach Island
21 Shovelers Lane
Manahawkin, NJ 08050-3178
ABSTRACT
A simple and inexpensive method for replenishing dunes based on "soft engineering"
principles using the natural forces of storm waves is described. The advantages and disadvantages
of other dune stabilization methods and ocean-side bulkheads are also discussed.
BACKGROUND
All regions in the U.S. having seashores and dunes are naturally subject to shoreline
erosion due to winds and storm waves. In many of these areas, particularly where there are
homes, recreational centers or industrial structures, dune erosion becomes a serious problem.
Coasts are dynamic regions where coastal erosion and deposition are constantly occurring and
where the impact of these processes on dunes and human-made coastal features are of great
concern.
Too frequently, these natural phenomena are poorly understood and ignored when
shoreline development is being planned and implemented. Many of the actions then undertaken to
correct dune or shore erosion either fail to work as intended or do not last long enough to benefit
their owners Dune and beach replenishment methods practiced in the U.S. are listed below:
• Pumping sand from the bay, ocean or the Continental shelf
• Transporting sand from the mainland
• Bulldozing beach sand into dunes
• Placing sand-fencing in dunes following a pre-arranged plan ("soft
engineering").
One of the most important considerations in pumping sand from the bayside of a barrier
island or the sand slope in front of a beach is the quality of the sand. Sediment pumped from bays
or estuaries is usually too fine to be used on open dunes; it is often muddy and quickly eroded;
pumping sand from bays also destroys eel grass important to the bay ecosystem. A better sand
source for replenishing U.S. beaches and dunes is the Continental Shelf. With relatively little or,
at least, no obvious environmental harm, offshore dredging yields sand closely resembling natural
dune and beach sand. This method is also the most expensive because of heavy equipment needed
to withstand the open-ocean waves. One of the largest beach nourishment projects ever
undertaken was completed by the U.S. Army Corps of Engineers in 1980 at Miami Beach, Florida
(1). More than 300 million cu. ft. of sand were pumped from one to two miles offshore for
deposition along a 10 mi section of beach at a total cost of $65 million.
Transporting sand fill overland to replenish ocean front dunes is commonly used in the
U.S. but the quality of the fill material must be carefully assessed. If the fill material contains sand
finer than the sand originally at the site, the finer sand will be quickly eroded away and deposited
offshore in waters still enough to allow deposition. Higher amounts of finer sand in the fill will
result in high losses to the littoral system and, therefore, necessitate more frequent refilling.
This paper describes a method for protecting and replenishing dunes that is both simple
and inexpensive. The method was developed over a ten-year period and the resulting dunes,
approximately 22 ft. high, have withstood attacks by severe storms along the U.S. New Jersey
coast for more than twenty years.
MATERIALS
The dune replenishment method ("soft engineering") described below requires the
following materials: approx. 40 ft. x 4ft. lengths of snow-fencing and wooden post approx. 6 ft. in
length and 4 in. diameter. The posts should be made from cedar or other wood not easily
decomposed.
239
-------
METHOD
The diagrams used to illustrate this process are not drawn to scale but are in the proper
proportions.
Figure 1 outlines the profile of an ideal ocean-side dune and the terms used to describe its
various land forms. The profile of a dune in need of replenishment (approx. 6 ft. above mean low
tide) is shown in Figure 2 Initially, two sections of fencing (approx. 40 ft. long) are erected facing
the ocean parallel to the water line or base of the existing dune. If more than one 40 ft. length of
fencing is to be used, the lengths should be separated by approx. 6 ft. The first length of fencing
(Aj) is placed approx. 3-4 ft. from the land-side slope of the dune; the second length (A2) is
placed toward the ocean approx. 12 ft. in front of A,. Figure 3 illustrates a higher dune profile
due to the deposition of sand from storm waves. At this point two more parallel lengths of
fencing (see Bj and B2 in Figure 3) are erected on the ocean-side of Aj and A2; Bj is approx. 12 ft.
in front of A2 and B2 is approx. 12 ft. in front of B,. In Figure 4, a second new dune profile has
been achieved (usually in about 2-3 years), depending on geographic location and weather
conditions. A, and A2 should be covered by approx. 4 ft. of sand. Figure 5 illustrates the erection
of three more barriers (see Q, C2, and C?). Barrier C, is spotted approx. 4ft. to the land-side of
the buried dunes A,, A2, B,, and B2; barrier Q would then be approx. 4 ft. on the ocean-side of
buried barrier A, ,C2 is placed 4 ft. on the ocean-side of buried B2. When sand has built-up
between Cl5 C2, and C3, as indicated in Figure 6 (4-5 years), vegetation indigenous to the area
must be planted on the ocean-side and crest of the dune as a means of stabilizing it against aeolian
effects. In the U.S. dune grass (Ammophila breviligulatd), sea oats (Uniolapaniculata), and salt
meadow grass (Spartina patens) are the most prevalent dune colonizer and stabilizers. When the
dune build-up reaches the dimensions illustrated in Figure 7, four new rows of barriers are erected
(see DI, D2, D3, and D4). At this point in following the Andres Method, the dune crest should be
approx. 6 ft. above its original height. D, should be placed 4 ft. on the land-side of C, D2 should
be 4 ft. on the land-side of C2 Cl5 C2, D3 and D4 should be separated by 4 ft. and must be erected
between the approx. locations of C2 and C3. The completion of this method of dune
replenishment is illustrated in Figure 8, where the desired effect should be achieved in approx. 6-8
years. When barriers D, to D4 are almost covered by sand, it is extremely important to plant the
ocean-side and crest of the dune again with plants indigenous to the region. Each spring, dunes
thus formed, should be fertilized using a granular inorganic 10-10-10 fertilizer rich in nitrogen.
Dunes having been built to approx. 20 to 22 ft., will withstand the onslaughts of most
severe storms offering adequate protection to the homes, structures, and communities behind
them.
Ocean-Side Bulkheads
Figure 9 shows an eroding shoreline and a gently sloping foreshore. Fear of further
shoreline erosion leads to the construction of an ocean-side bulkhead. After construction of the
bulkhead (see Figure 10), the beach, due to the scouring effect of wave action, begins to narrow
and the offshore underwater slope begins to steepen. As illustrated in Figure 11, after approx. 2-
10 years, the beach has disappeared; the offshore slope has steepened; the building above it has
begun to show serious structural damage and the bulkhead has begun to fail. Finally, Figure 12
shows the loss of the building that was above the bulkhead; wave size has increased, and a bigger
bulkhead is required. The original sandy beach has been completely lost.
SUMMARY
As stated in the introduction, coastal erosion is a natural process that only becomes a
problem when it threatens human-made structures or land considered valuable by society. When
dune erosion is a problem, a thorough understanding of the physical processes causing it, e.g.,
geographic and geologic factors, is invaluable when planning remediation. Considering all of the
dune replenishment methods discussed in this paper, the most effective, inexpensive, and practical
method is the Andres Method.
The use of ocean-side bulkheads may, in most instances, protect communities from ocean-
wave flooding but the loss of any sandy beach in front of ocean-side bulkheads is inevitable. An
inspection of any N.J. coastal community protected by ocean-side bulkheads will substantiate this
conclusion (see also Appendix A and ref. 2)
240
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LITTORAL OR NEARSHORE ZONE
BEACH OR SHORE
COAST
^
^
DUNE
K)
HIGH WATER LEVEL
Figure \. Beach profile.
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
Figure 2. The beginning of the Andres Dune Replenishment Method.
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
to
^
U)
Figure 3. Two more barriers added (see BI and
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
Figure 4. A Second new profile has been created (2-3 years).
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
ro
-u
C2
C3
Figure 5. Erection of third set of barriers (Cr, Ci, and
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
to
-U
ON
Figure 6. Third profile created. Dune stabilized by vegetation (4-5 years).
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
Figure 7. Erection of fourth set of barriers (Di-D4>.
-------
ANDRES SYSTEMATIC DUNE REPLENISHMENT METHOD
to
-tk
00
Figure 8. Completion of dune replenishment (6-8 years).
Dune stabilization by vegetation important.
-------
VO
Gentle foreshore-*"*
Before the bulkhead
Figure 9.
-------
K)
Wi
O
Narrowing of
beach
beach; additional housing built).
-------
Two or more years later (no beach;
offshore slope steepened; property
threatened).
Figure 11.
-------
to
Bigger Seawall
Figure 12.
Approximate
property gone
-------
ASSESDVG SHALLOW WATER CONDITIONS USING IMAGING SPECTROSCOPY
AND VIDEOGRAPHY
Sima Bagheri, Ph.D.
New Jersey Institute of Technology
Newark, NJ 07102
Matt Stein
Maverick Marine Services
Sanibel, Fl 33957
Christine Zetlin
NOAA Sandy Hook Laboratory
Highland, NJ 07732
ABSTRACT
The study investigates the utility of the Airborne Geophysical Environmntal Research
(GER) Imaging Spectrometer and XYbion MSC-02 multispectral video camera in hydrological
feature extractions in nearshore waters. The spectral characterization of these waters is mainly
produced by the organic (phytoplankton), inorganic (suspended sediments) and Dissolved Organic
Matter (DOM). The airborne systems -- GER Imaging Spectrometer and XYbion MSC-02
Multispectral Video Camera used here provide spectral coverage from 0.4-1.1 ^m which is the
only electromagnetic spectral range in which signals from hydrological volume —i.e., originating
below the surface and thus directly from the water column — is originated. Present work is
focused on the evaluation of airborne systems for assessment of water quality conditions and
model development. Such developmental use will greatly aid the forthcoming transition to the
next generation of space-borne systems for nearshore ecosystem monitoring and management.
STUDY AREA
The test site is the New Jersey estuarine and coastal waters (Figure 1), where the
multiplatform/multitemporal remotely sensed data has been investigated with the goal of
developing a cost effective operational monitoring system (Bagheri et. al., 1992). The
Hudson/Raritan Estuary is an important ecological, commercial and recreational asset within New
York-New Jersey metropolitan area (Figure 1). It is a partially mixed system consisting of broad
water bodies as well as narrow channels and rivers. It displays an extremely complex interaction
of tidal and wind-driven currents modified by freshwater discharges --Hudson and Raritan rivers
and oceanic waters enter tidally across the Sandy Hook-Rockaway transect (Oey, 1985).
DATA CHARACTERISTICS AND DATA ANALYSIS
The two sets of data were acquired independently on two different dates — June 11, 1990
and October 7, 1992. In addition, the radiometric sensitivities of the two systems are very
different But unlike spaceborne sensors airborne systems can acquire optical information through
frequent overflights with higher spectral/spatial resolution both timely and cost effectively.
Table 1. Specification of the MSC-02 Camera
Radiometric Resolution
IFOV
Ground EFOV at 3000 m
Scan Angle
No. of Pixels/Scan
12 bit
3.3 mrad
~10m
90 degree
512
253
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Table 2. Specification of the GER-Scanner
Radiometric Resolution
Spectral Coverage
Shutter Aperture
Adjustable Filter Set
No. of Pixels/Frame
Ground Resolution at 400-500 m
8 bit
0.4-1.0 /j.m (in step of 50nm)
1/250-1/10,000 sec
up to 70 nm bandwidth
350x445
~lm
DATA ANALYSIS AND INTERPRETATION
Sea Truth Data Collection and Analysis
Sea truth data were collected using a shipboard automated sampling system.
Temperature, conductivity and fluorescence were monitored and averaged for each minute during
data acquisition. A continuous-flow fluorometer set-up for chlorophyll-a analysis was used to
measure pigment flouresence (Figure 2).
MSC-02 Data Analysis
The images were acquired under overcast condition on June 11, 1990 concurrently with
surface water sampling. The target reflectance (Rt) was calculated as:
Rt = aEu/aEd (Eq.l)
The appropriate relative calibration functions f(DN) for 6 bands, images of halon coated panels
with reflectance (Re) equal to 1.0 were obtained in all bands and at all F-stops. XYbion claims
that instrument responses in each band (x) are linear, i.e.:
aEx = f(DNx) = mJtDNx + bx (Eq.2)
Where n^ and bx are relative radiometric gain and bias for each band. Relative radiometric
functions obtained by linear regression of estimated transmitted radiances against corresponding
panel DNs These functions used to calculate the relative irradiances (aEx) of both panel and
water targets. These were input to Equation 1, to produce (Rt). The models for chlorophyll-
a/total suspended sediments were linear yielding R2 of 0.77 and 0.72 for bands 2 and 4 at
probability of 0.10 and 0.16 respectively.
GER Data Analysis
GER data were acquired under clear atmospheric conditions on October 7, 1992.
Variations resulting from phytoplankton and suspended sediment concentrations were
insignificant because at the time of that data acquisition, there was a time lapse between the
(phytoplankton) blooms. Sea truth data also confirmed the absence of the blooms as a direct
result of the date of the image acquisition. And there was, no oil spill on this date. The
homogeneous water optical properties and uniform bottom type provided the potential to
measure bathymetry using a model introduced in Philpot (1989):
X =ln(Ld-Lw) = ln(Lb)-gz (Eq.3)
Ld = radiance observed at the remote detector.
g = an effective attenuation coefficient of water.
z = depth of the water column.
Lb = a radiance term which is sensitive to bottom reflectance.
Lw = remotely observed radiance over optically deep water (gz —>).
254
-------
All the parameters, except for depth, are wavelength dependent and L^ 1^,, and g are
assumed constant. GER bands 08 and 12 corresponding to spectral bands; -570 and ~650 nm
respectively, selected for detection of bottom features. Figure 3 shows the location of the
transect — 2 selected for this study.
NOAA-NGDC depths and corresponding GER-derived X values (Eq. 3) were extracted
from the rectified data grids. Data extractions were performed for the central 20% of columns of
the GER image to avoid pronounced surface-reflectance and "fall off' effects in the GER X-
values (Figure 3). GER band 08 and 12 correlated highest, with R2s of 0.642 and 0.624,
respectively (depth range 0-8 meters).
CONCLUSION
The current results suggest that both the XYbion MSC-02 and GER provide useful real
time digital data for assessing shallow water environmental monitoring conditions. The MSC-02
demonstrated its capability to monitor water quality under the most adverse weather conditions.
And GER's detection of the bottom suggests that it could easily have detected variations in water
quality had any existed.
Our findings do not attempt to represent a true comparison between MSC-02 versus GER
data for any given applications. Such a realistic comparison would additionally require substantial
ground truthing and simultaneous data acquisition with sensors to evaluate additional water
quality parameters, and to discriminate between effects of these versus effects of depth/bottom
type.
ACKNOWLEDGMENT
This research is supported by the National Science Foundation (BSC-9210232). The
author wishes to acknowledge Jim Nickels of New Jersey Marine Sciences for his assistance in
sample collection and NOAA Sandy Hook Laboratory for the provision of facilities for data
analysis.
REFERENCES
Oey, L.-Y., Mellor, G.L., and Hires, R.I., "A Three-Dimensional Simulation of the
Hudson/Raritan Estuary." Part I&II. Journal of Geophysical Oceanography
15:12:1676-1709(1995).
Philpot, W.D., 1989. "Bathymetric Mapping with Passive Multispectral Imagery", Applied
Optics, Vol.28, No.8, pp. 1569-1578.
255
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HUDSON RIVER FOUNDATION FOR SCIENCE AND ENVIRONMENTAL RESEARCH. INC. 1*10
Figure 1. Map of the Study Area with Locations of the Transects
( ), GER ( ), MSC-02.
256
-------
TOTAL PIGMENTS AND FLUORESCENCE
TRANSECT 1. OCTOBER 7.1992
Figure 2. Sum of Chlorophyll-a and Phaeopigment concentration vs,
Total Fluorescence
257
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3UK;ACE
£EFLECTANC c
ROCKAWAY
POINT
BR E AKWi"£:1
ROMER
SHOAL
SANDY
HOOK
Figure 3. "Transect 2" of GER spectral bands 8 and 12
corresponding to (-570 and —650 nm)
258
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DEVELOPMENT AND USE OF A SPREADSHEET MODEL
PREDICTING COPPER LOSSES FROM CCA TREATED WOOD IN AQUATIC
ENVIRONMENTS
Kenneth M. Brooks, Ph.D.
Aquatic Environmental Sciences
644 Old Eaglemount Road
Port Townsend, WA 98368
INTRODUCTION
For many years the treated wood industry believed that metals in CCA treated wood were
"fixed" and did not leach. Industry advertised treated wood that would always last 25 years. The
reality is that properly treated and fixed, wood of the right species will last for significant periods
of time with minimum loss of chemicals. Treated wood is preserved with natural biocides —just
as naturally resistant species contain potent biocides like the tropolones in western red cedar.
CCA incorporates copper and arsenic to extend the life of more common, but less resistant
species of wood. These are naturally occurring metals that are ubiquitous in aquatic systems.
The Columbia River discharges an average of 886 kilograms of copper per day -- just in the water
column.
Water Quality Criteria
The Environmental Protection Agency has a current marine copper standard of 2.9 ppb.
However, this criteria is under review (EPA, 1995) and it appears that a Final Acute Value of
10.39 ug-L"1 dissolved copper is more appropriate. This will result in a new Criterion Maximum
Concentration (CMC) of 4.8 ug Cu-L"1. The National Technical Information Service (NTIS,
1986) suggests that arsenic effects on aquatic organisms are observed at greater than 100 ng-L"1
arsenic HI (the more acute ionic form). Washington State water quality standards are based on
apparent effects thresholds (WAC 173-201). These chronic standards suggest that copper (2.9
Ug-L'1) is more toxic than arsenic (36 jig - L"1) or chromium VI (50.0 jig-L"1). In addition, at the
retention's used in marine environments (40 kg CCA-m"3), CCA treated wood loses a higher
proportion of copper than of arsenic or chromium in marine environments. Because of its
toxicity, copper forms the basis of this risk assessment. If we maintain copper concentrations
below the EPA regulatory level of 2.9 ug Cu-L"1, arsenic and chromium are unlikely to affect
aquatic resources.
Copper Losses from CCA Treated Wood
The literature indicates that CCA retention, salinity and time are important factors in
determining copper losses. The current model is based on data from studies using southern
yellow pine. Baseline copper losses were developed by regression analysis on data in Baldwin et
al. (1994) and Lee (1993). These data indicate that properly fixed CCA preserved wood initially
loses 2.6 ug cm"2 per day. Metal losses, as a function of time are summarized in Table 1. These
data are only for the prescribed marine retention of 40 kg CCA m"3 At lower retention's, the
proportion of metals lost to CCA leachates changes. Assessments of treated wood performance
must use the preservative retention required by AWPA (1992) for the environment of interest.
Irvine and Dahlgren (1976) examined metal losses from CCA as a function of salinity.
We have used non-linear regression analysis to predict changes in copper losses as a function of
salinity. Loss rates are lowest at an estuarine salinity of 14 parts per thousand (ppt) and increase
in either fresh or marine environments.
Warner and Solomon (1990) used a citric acid ~ sodium hydroxide buffer system to
demonstrate high metal loss from CCA treated wood at low pH. However, Cooper (1990, 1991)
clearly demonstrated that the high losses reported in Warner and Solomon (1990) were a function
of the buffer system used and not solely of the pH. Metal losses from CCA do increase at low
pH. However, the values (pH < 4.5) at which significant increases are observed are not
environmentally realistic. At pH values this low, the wood fibers begin to break down with a loss
of structural integrity. This model does not include an algorithm for pH.
259
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Table 1. Average daily leaching rates (jig-cnr'-day1) of arsenic, copper and chromium observed in large scale,
agitated seawater leaching experiments on CCA-C treated poles. (Baldwin et aL, 1994).
Leaching Rates (jig-cm 2-day ')
Period Copper Arsenic Chromium
0 through day 7 2.6 1.1 0.13
Day 7 to 14 1.7 0.7 0.05
Day 14 to 21 1.6 0.4 0.04
Day 21 to 28 1.4 0.5 0.04
Teichman and Monkman (1966) tested thin CCA treated wafers and found that metal
losses were halved each day during the first three days of their test. Fahlstrorri et al. (1967)
found highest metal losses from CCA treated wood during the first six hours. They recorded 1/5
to 1/10 the initial loss rates after 18 hours and reported losses of 1/100 the initial rates at the end
of 24 hours. Cockroft and Laidlaw (1978) suggested that the rate of preservative depletion varies
with the inverse square root of time. For the purposes of this model, the Baldwin et al. (1994)
data was submitted to non-linear regression analysis. The results indicate that metal loss
decreases exponentially and is reduced to about one percent of the initial value within 90 days.
Combining factors for retention, salinity and time provides us with an estimate of the copper
losses from CCA treated wood used in aquatic environments. In this equation you can see that
retention, salinity and time are important parameters.
Copper Loss = gxp-004"1"*"16^ x 0.51 exp°02(SlBllhy) x (0.55 + 0.65 Natural Log (0.71 Retention)
Copper Transport and Fate
Two models have been developed to look at typical CCA projects in marine water. The
first model deals with piling and is called CCAPRISK. The model assumes that copper is lost
from the piling and diluted in the water column. Diffusion is shown to be of little importance and
dilution is a function of currents. Because we are interested in the maximum observable copper
levels, the model integrates tidal currents within half an hour of slack tide. Water column
predictions assume that all of the copper remains dissolved in the most toxic cupric ion state, and
sediment predictions assume that all of the copper is adsorbed to and deposited with silt. The
model is conservative in that the sum of the mass loading to the water column and sediment is
twice the actual copper released from the piling. The following assumptions have been made in
constructing the model.
• The volume of the receiving water is large in comparison with the amount of
preservative being considered. In marine environments, the surface area of the
receiving water should be greater than 259 times the immersed area of CCA
treated structure.
• That detoxification processes due to chelation, complexation and sedimentation
are long compared with the speed of the current and uptake by aquatic
organisms.
• That released copper adsorbs to the silt (3 to 63 micron) fraction of the
suspended paniculate load and is sedimented with the silt.
• We ignore the potential for recycling of copper from aerobic sediments back
into the interfacial water. Washington State sediment standards are based on
Apparent Effects Thresholds and it is assumed that bioassays, upon which these
standards are based, naturally account for cycling of sediments from aerobic
sediments.
The model is designed with input parameters that are easily estimated or obtained from
Seagrant, NOAA and other sources. Input parameters include CCA retention, piling radius, piling
age, salinity, tidal velocity, steady state currents and local, state or federal copper standards.
260
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Table 2 provides an example of the input and partial output. In this marine piling
application, the model predicts a water column concentration of 32.7 parts per trillion where
maximum tidal currents are 2.5 cm sec"1. That is one eighty ninth of the current EPA limit of 2.9
ppb. In this case we have spaced two pilings two meters apart. The model predicts the eventual
accumulation of 5.27 ppm copper in adjacent sediments. This is a small fraction of Washington
State's sediment quality standard of 390 mg kg"1 (dry sediment weight).
261
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Table. 2a. Tabular output from the Microsoft EXCEL ™ spreadsheet A:\CCAPrisk.
Water column copper concentrations associated with piling.
Copper Accumulation in Waster and Sediments Associated with the use of
CCA Treated Wood
User Entries
1. Retention (kg m"3)
2. Average piling radius (cm)
3. Piling Age (days)
4. Salinity (parts per thousand, ppt)
5. Settling Velocity (0.05 for silt; 0.00005 for clay)
6. Average Maximum Tidal Velocity (cm sec"1)
7. Steady State Currents (cm sec"1)
8. Marine Sediment Copper Quality Standard (mg kg"')
9. Maximum Marine Sediment Impact Zone Cu Std. (mg kg"*)
10. Freshwater, Chronic, Copper Standard (ng I/')
11. Water hardness (mg kg"1 CaCO3)
12. Marine Water Copper Standard (jig L"1)
13. Sediment Density (gm cm"3)
14. Bulkhead Length (cm)
15. Board Width (cm) (2x6 = 14,2x8 = 19. 2x12 = 29.2)
16. Average Water Depth in the Mixing Width (cm)
40.00
15.00
0.00
28.00
0.050
2.50
0.00
^^^^^m
390.0
0
m^^mimm
390.0
0
^^^^^m
3.62
25.00
2.50
2.2
10000
13.97
250.0
0
Intermediate Output
Migration (ng cm"2day"')
Age Factor
Retention Factor
Mixing Width (cm)
Model Velocity (cm sec"1)
Geometry Factor
2.72
1.00
0.99
40.00
1.60
1.16
Water Column Copper Concentration
Associated With CCA Treated Piling
Water Cone, (ng L"1)
Marine Water Standard
Freshwater Standard
0.033
2.900
3.617
262
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Tablc2b. Predicted Sediment Copper Levels in micrograms/square cm sediment surface, or ppm
Sediment Copper Levels
Distance
200
175
150
125
100
75
50
25
5
25
50
75
100
125
150
175
200
Accumulation
PI (MS cm:3)
0.14
0.16
0.19
0.22
0.27
0.34
0.47
0.77
1.54
0.77
0.47
0.34
0.27
0.22
0.19
0.16
0.14
Accumulation
P2 (ug cm'2)
1.54
0.77
0.47
0.34
0.27
0.22
0.19
0.16
0.14
0.13
0.12
0.11
0.10
0.09
0.08
0.08
0.07
Total Cu Ace.
(Hg cm'2)
1.69
0.93
0.66
0.56
0.54
0.56
0.66
0.93
1.69
0.90
0.59
0.45
0.37
0.31
0.27
0.24
0.22
Cu Cone.
(mgkg-1)
0.38
0.21
0.15
0.14
0.13
0.12
0.15
0.21
0.38
0.20
.0.13
OJO
0.08
0.07
0.06
0.05
0.05
Sed. Std.
(mgkg-1)
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
SIZ Maximum
(mgkg-1)
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
390.00
Testing the Model
Environment Canada (EVS, 1994) has tested a similar creosote model and it very
accurately predicted the levels of PAH observed at two sites in British Columbia. Unfortunately,
we have not yet completed an environmental scale test of the CCA model. We have compared
predicted copper loss rates with leaching data available in the Weis papers. A paired sample t test
at a = O.OS did not find a significant difference between predicted and observed copper levels.
The South Carolina Wildlife and Marine Resources Department completed an evaluation
of new residential docks and their affects on marine life in South Carolina Tidal Creeks in 1994
(Wendt et al., 1995). The following quote summarizes this study.
"In summary, our findings suggest that, in natural estuarine environments subject to
normal tidal exchange, wood preservative leachates from dock pilings have no acutely toxic
effects on four common estuarine species, nor do they effect the growth and survival of oysters
over a six week period. In some cases, metal leachates may accumulate in sediments and oysters
immediately adjacent to pilings, but do not appear to become concentrated in sediments or oysters
elsewhere in the same creeks."
This report, which represents the first environmental scale risk assessment of CCA treated
wood, is consistent with model predictions showing low environmental risks associated with CCA
treated piling.
CCA treated bulkheads present a different problem. Copper is lost from CCA treated
lumber and enters the water column where it adsorbs to suspended particulates. As the water
moves down the bulkhead, turbulence dilutes the copper. We have used a very modest turbulence
model. Water traveling along a 100 meter long bulkhead at 2.5 cm sec"1 would be mixed to a
width of 62.5 cm or about two feet. The mixing width is a function of water speed and water
flowing at 20 cm sec'1 would be mixed to a width of 5.0 meters.
Input for the bulkhead model is similar to that for the piling model. However, in this
model we are also interested in the bulkhead length, the slope of the bottom next to the bulkhead
and the dimensions of the treated wood. As an example, consider a marine bulkhead that is 100
meters long, built of 2 x 6's with an average water depth of one meter in the mixing width. With
263
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no steady state current, and maximum tidal currents of 5.0 cm sec"1, the model predicts that the
project will add 1.58 ug Cu L"1 during the first day following installation. The predicted long
term sediment concentration of copper is 3.74 mg Cu kg"1 (dry sediment). This is well below
Long and Morgan's (1990) Effects Range - Low level of 70 mg Cu kg"1 (dry sediment weight).
The model does predict that when bulkheads are built along canals or seashores, EPA water
quality criteria may be exceeded for a short period of time when maximum tidal currents are less
than 4 cm sec"1.
CCA and Endangered Salmon Populations
Copper can have subtle affects on fish. Giattina, et al. (1982) reported copper avoidance in
rainbow trout (Oncorhynchus mykis) at levels of 4.4 - 6.4 ug L'1 in soft water (28 ppm as
CaCO3). Lorz and McPherson (1976) exposed ten- to eighteen-month-old coho salmon
(Oncorhynchus kisutch) to varying levels of copper and then released them into a tributary and
observed migratory behavior. Exposure to 5 ug L"1 copper for 165 days resulted in a 30%
reduction in downstream migration. Short term (one to three day) exposure to low levels (<8 ug
L"1) copper were not investigated. However, it appears that copper levels above 5 ug L"1 should
be avoided during periods of active salmonid migration.
Reproductive success is negatively influenced by elevated copper levels in numerous
species. The available information is reviewed by Sorensen (1991). Scudder et al. (1988) report
17% premature hatching in brook trout eggs incubated at 32.5 ug L"1 copper. No adverse effects
were observed at copper levels less than 17.4 fig L"1 copper. Mount and Stephen (1969) report
that while copper concentrations of 18.4 ug L"1 kill half of the fathead minnows (Pimephales
promelas) used in reproductive studies, survival, growth, and reproduction were normal at 4.4 to
10.6 ug L"1 copper. They did observe higher NOEL (No Observed Effects Levels) in hard water
(200 ppm CaCO3). Hazel and Meith (1970) report that copper levels exceeding 100 ug L'1 will
kill king salmon (Oncorhynchus tshawytschd) eggs. No mortality was observed at 8 ug L"1
copper.
In summary, freshwater species offish are more sensitive to metals than are marine
species. Higher salinity and hardness in marine water protect fish from copper poisoning as do
factors such as pH, dissolved organic material and alkalinity which increase the potential for Cu*2
complexation and detoxification. It appears that growth and survival are affected at higher
copper levels than is successful migratory behavior, reproduction and survival of larval stages.
Copper levels greater than 17.4 ug L"1 can adversely affect the number of eggs spawned,
hatchability and larval survival. At intermediate hardness values Tea. 50 mg L'1 CaCO3) migratory
impairment can occur at constant copper levels as low as 5 ug L" . This suggests that
Washington State regulatory levels for copper are adequate to insure reproductive success with
the exception that more strict standards should be imposed (< 5.0 jig L"1) during periods of active
salmonid migration.
These risk assessment models have been used to examine the risks to threatened or
endangered salmonid populations in the Columbia River (Brooks, 1995b). For this analysis, the
dilution algorithm was modified to enhance predictive capabilities in lotic freshwater systems. The
copper criteria (6.54 ug L"1) is based on an average Columbia River hardness of 59.5 mg L"1
CaCO3 (Johnson & Hopkins, 1991). An alternate criteria of 5.0 ug L"1 copper should be imposed
on projects constructed within one week of an active salmonid migration. Background copper
levels are assumed to be 1.55 ug L"1 which is the average reported by Johnson and Hopkins
(1991). Thirty centimeter diameter piling, treated to 1.0 pcf (15.6 kg-m"3) are modeled in
freshwater with a pH of 8.11.
The steady state dilution model developed in this report is used to predict copper
concentrations immediately adjacent to the piling. Water column copper concentrations for a
variety of current speeds are predicted in Table 3. In very poorly flushed areas with current
speeds of 0.1 cm sec"1, CCA piling increase the copper content in the water immediately adjacent
to the piling from a background of 1.55 ug-L"1 to 2.10 ug-L'1. At more realistic minimum current
speeds of 5 cm sec"1, the copper content of the water is increased by only 0.39 percent to 1.556
ug-L"1. These data indicate that CCA treated piling used in the Columbia River present a No
Effect application with respect to listed salmonid species.
264
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To put the copper losses from CCA in perspective, consider that a freshwater project
involving 100 CCA treated piling, installed in five meters of water would add 74.9 grams of
copper to the Columbia River during the first 30 days when most of the CCA loss occurs. During
those 30 days, the Columbia river transports 26,585 kg of copper in the water column. The
copper lost from 100 CCA piling during the first 30 days is equal to the natural copper contained
in 7.3 seconds of Columbia River flow and increases the Columbia's copper content by a factor of
2.8x10^
Table 3. Water column copper concentrations of copper immediately adjacent to a 30 cm diameter piling,
treated with CCA to a retention of 15.6 kg-m°, as a function of current speed. Ambient pH is 8.11, background
copper levels are 1.55 ug-L'1, and the salinity is 0.0 ppt.
Current Speed
(cm-sec"1)
0.1
0.5
1.0
2.0
3.0
4.0
5.0
10.0
15.0
Total Copper
(ng-L-1)
2.096
1.659
1.605
1.577 •
1.568
1.564
1.556
1.554
1.553
Copper increase due to CCA treated
(ttg-L-1)
piling
0.546
0.109
0.055
0.027
0.018
0.014
0.006
0.004
0.003
CONCLUSION
In summary, these models do not predict that CCA treated wood is an appropriate
material for every project. They strongly suggest that CCA treated piling will rarely result in
exceeding water quality criteria. In addition, when constructed in reasonably well-flushed marine
environments, CCA bulkheads pose minimal risks. In poorly flushed canals, there is a potential
for short-term, localized exceedances of water quality criteria.
The models are based on CCA treated wood in which proper fixation was determined
using the chromotropic acid test. The Western Wood Preservers Institute has recently developed
Best Management Practices for the production of treated wood destined for aquatic
environments. These BMPs are designed to optimize the environmental performance of treated
wood and to provide predictability with regard to these models. They are being required as a
condition on permits issued on the west coast.
We have spent years developing water and sediment quality criteria. These regulatory
standards provide a basis for permitting projects. The risk assessment models presented here are
intended as a tool that will enable proponents, engineers and permit writers to assess specific
projects against those regulatory levels and to identify and modify inappropriate projects. I
believe this kind of analytical process is necessary if we are to rebuild public support for
sustainable resource programs.
REFERENCES
AWPA, 1992. American Wood-Preservers'Association Book of Standards. American Wood-
Preservers Association, P.O. Box 286, Woodstock, MD 21163-0286. 290 pp.
Baldwin, W.J., E.A. Pasek, P.O. Osborne. 1995. Sediment Toxicity Study of CCA-C
Treated marine Piles. American Wood-Preservers' Association 90th Annual Meeting
held at the Marriott Rivercenter Hotel, San Antonio, Texas, May 14-18, 1994.
Brooks, K.M. 1995a. Literature Review, Computer Model and Assessment of the
Environmental Risks Associated with the use of CCA Treated Wood Products in Aquatic
Environments. Published by the Western Wood Preservers Institute, 601 Main Street,
Suite 401, Vancouver, WA 98660. 137 pp.
265
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Brooks, K.M. 1995b. Assessment of the Environmental Risks Associated With the Use of
Treated Wood in Lotic Systems. Published by the Western Wood Preservers Institute,
601 Main Street, Suite 401, Vancouver, WA 98660. 137 pp.
Cockcroft, R. and R.A. Laidlaw. 1978. Factors affecting leaching of preservatives in practice
International Research Group on Wood Preservatives.Document IRG/WP/3113. 10 pp.
Cooper, P. A. 1990. Leaching of CCA from treated wood. Proc. Canad. Wood Preserv. Assoc.
• 11:144-169..
Cooper, P. A. 1991. Leaching of CCA from treated wood: pH effects. Forest Prod. J.
41(l):30-32.
EPA. 1995. Ambient Water Quality Criteria - Saltwater Copper Addendum, DRAFT dated
April 14, 1995. U.S. Environmental Protection Agency, Office of Water, Office of
Science and Technology, Washington, D.C. 35 p.
EVS Consultants. 1994. Creosote evaluation project. Report prepared for the Creosote
Evaluation Committee. Fraser River Estuary Management Program Technical
Report WQWM 93-13. 49 p.
Fahlstrom, G.B., P.E. Gunning and J.A. Carlson. 1967. Copper-chrome-arsenate wood
preservatives: a study of the influence of composition on leachability. Forest Prod. J.
17(7): 17-22.
Giattina, J.D., R.R. Garton and D.G. Stevens. 1982. Avoidance of copper and nickel by
rainbow trout as monitored by a computer-based acquisition system. Trans. Am. Fish.
Soc. Ill, p. 491.
Hazel, C.R. and S.J. Meith. 1970. Bioassay of king salmon eggs and sac fry in copper
solutions. Calif. Fish and Game. 56. p. 121.
Irvine, J. and S.E. Dahlgren. 1976. The mechanism of leaching of copper-chrome-arsenic
preservatives from treated wood in saline waters. Holzforschung 30(2):44-50.
Johnson, A. and B. Hopkins. 1991. Metal and Fecal Coliform Concentrations in the Lower
Columbia River. Washington State Department of Ecology letter dated May 31, 1991.
Lee, A.W.C., J.C. Crafton III and F.H. Tainter. 1993. Effect of rapid redrying shortly after
treatment on leachability of CCA-treated southern pine. Forest Products Journal.
1993:52.
Long, E.R., and L.G. Morgan. 1990. The potential for biological effects of sediment-sorbed
contaminants tested in the national Status and Trends Program. NOAA technical
Memorandum NQS OMA 52. Seattle, Washington. 175 p.
Lorz, H.W., and B.P. McPherson. 1976. Effects of copper or zinc in fresh water on the
adaptation to sea water and ATPase activity and the effects of copper on migratory
disposition of coho salmon (Oncorhynchus kisutch). J. Fish. Res. Bd. Can., 33, p. 2023.
Mount, E.I., and C.E. Stephen. 1969. Chronic tpxicity of copper to the fathead minnow
(Pimephalespromelas) in soft water, J. Fish. Res. Bd. Can., 26. p. 2449.
NTIS. 1986. Quality Criteria for Water: ARSENIC, 1986. NTIS #PB 85 227445
Scudder, B.C., J.L. Carter, and H.V. Leland. 1988. Effects of copper on development of the
fathead minnow, (Pimephalespromelas) Rafinesque. Aq. Toxicol. 12. p. 107.
Sorensen, E.M. 1991. Metal poisoning in fish. CRC Press, Inc. 2000 Corporate Blvd., NW,
Boca Raton, Florida, 33431. 374 pp.
Teichman, T. and J.L. Monkman. 1966. An investigation of inorganic wood preservatives. I.
The stability to extraction of arsenic impregnated hardwood. Holzforschung. 20(4):
125-127
Warner, J.E. and K.R. Solomon. 1990. Acidity as a Factor in Leaching of Copper,
Chromium and Arsenic from CCA-Treated Dimension Lumber. Environmental
Toxicology and Chemistry. 9:1331-1337.
Wendt, P.H., R.F. Van Dolah, M.Y. Bobo, T.D. Mathews, and M.V. Levisen. 1995. A study of
wood preservative leachates from docks in an estuarine environment. Final Report
prepared for the South Carolina Department of health and Environmental Control, Office
of Ocean and Coastal Resource management, pursuant to NOAA award No. NA
370Z0069-01. Prepared by the South Carolina Department of Natural Resources, Marine
Resources Division, Charleston, South Carolina. 31 p.
266
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SHALLOW COASTAL LAGOONS AS A RECRUITMENT HABITAT FOR BLUE
CRAB POSTLARVAE
Robert D. Brumbaugh and John R. McConaugha
Department of Oceanography
Old Dominion University
Norfolk, VA 23 529-0276
Running Title: Shallow Coastal Lagoons
Key Words: lagoon, blue crab, Callinectes sapidus, recruitment
ABSTRACT
The recruitment of blue crab (Callinectes sapidus) postlarvae, or megalopae, to coastal
lagoons along Virginia's lower Eastern Shore was investigated in 1993-1994. Habitat
requirements of megalopae in this environment are largely unknown and the suitability of coastal
lagoons as a recruitment habitat has been questioned. Seagrass beds, considered to be vital
refuges for juvenile blue crabs in Chesapeake Bay, are largely absent in these lagoons. In general,
the shallow coastal lagoons along the lower Delmarva Peninsula are well-mixed, with little or no
freshwater input. Water is exchanged with the coastal ocean through several tidal inlets, and
horizontal and vertical variation in temperature or salinity within the lagoons is negligible.
To determine the residence time of water in the lagoons, flux studies were conducted in
1993 at the three major inlets along the lower Eastern Shore. Hourly measurements of current
speed and direction were taken throughout the water column, along with temperature, salinity,
fluorescence, and dissolved oxygen. Using a modified tidal-prism approach, the residence time of
water in the southern lagoons was estimated to be approximately 5 tidal cycles, or 60 hours.
Subsequent experiments have shown that megalopae entering the lagoon can metamorphose
within that time frame, making the lagoons a potential habitat for settlement and metamorphosis.
INTRODUCTION
Most research on the early life history of the blue crab, Callinectes sapidus, has been
conducted in large estuaries such as Chesapeake Bay. These efforts have focused on larval
dispersal patterns in coastal waters, postlarval recruitment mechanisms, and juvenile habitat
requirements within large estuaries (Johnson, 1985; McConaugha, 1988; Epifanio, 1988; Orth &
van Montfrans, 1990; Little & Epifanio, 1991). However, little is known about the factors that
affect the abundance of blue crabs in the shallow coastal lagoons that occur along much of the
Atlantic and Gulf of Mexico coasts. Virginia's outer coast is fringed by such lagoons, which are
fundamentally different from partially stratified estuaries like Chesapeake Bay. Megalopae, which
reinvade coastal embayments after a period of larval development offshore, may respond
differently to environmental factors in coastal lagoons compared to larger estuaries such as
Chesapeake Bay.
The Lagoonal System
I. Physical Environment
Coastal lagoons are fundamentally different from larger estuaries such as Chesapeake Bay.
Chesapeake Bay is partially stratified, with lighter, less saline water overlying more dense, higher
salinity water. This type of two layer circulation is established by freshwater inputs from rivers
emptying into the Bay.
The lagoonal system has no significant source of freshwater. Circulation is dominated by
tidal currents which exchange water through narrow inlets between offshore barrier islands.
Therefore, the residence time of water within the lagoons is determined by the amount of water
that passes through the inlets with each tidal cycle (the tidal prism). The tidal prism is, in turn,
affected by the spring-neap tidal cycle, as well as local and non-local forcing mechanisms (Wong
&DiLorenzo, 1988; Wong, 1986, 1991).
267
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II. Postlarval Habitat
Seagrasses (primarily Zostera marina in Chesapeake Bay) are considered to be an
important refuge for early life history stages of marine fishes and invertebrates (Weinstein &
Brooks, 1983). However, seagrasses are largely absent from Virginia's coastal lagoons.
Seagrasses were wiped-out around the North Atlantic basin following an epidemic of Wasting's
Disease in the 1930s (Orth & van Montfrans, 1990). While seagrass beds have recovered in many
areas,-including Chesapeake Bay, they have not reestablished themselves within the coastal
lagoons. Thus, postlarvae and juveniles of species recruiting to the lagoons must utilize
alternative habitats, such as flooded Spartina altemaflora marshes and patches of benthic
macroalgae. The lagoonal system along Virginia's lower Eastern Shore is composed of shallow
subtidal flats bisected by deep channels extending from the tidal inlets to the interior of the
lagoon. These flats support various species of benthic macroalgae, including Ulva lactuca
(Chlorophyta) and Gracilaria spp. (Rhodophyta).
METHODS
Inlet surveys were conducted in 1993 and 1994 to determine the flushing time of the
lagoons along Virginia's lower Eastern Shore and to monitor postlarval ingress. Tidal currents
were monitored for 25 hours (two tidal cycles) at the three major inlets along the lower Eastern
Shore on separate occasions in 1993 (Figure 1). Smaller inlets to the south of Sand Shoal Inlet
were not monitored as they are less than 2 meters deep and probably contribute little to the
overall tidal prism of the lagoons. The physical dimensions of the three inlets in the study are
shown in Table I. Hourly measurements were taken from a 5-meter boat anchored in the center
of each inlet. Current speed and direction were measured at 1 meter depth intervals with an
ENDECO current meter. Currents were later decomposed into the along-channel components,
and vertically averaged to provide an instantaneous measure of flux through each inlet. Transport
of water through each inlet was calculated and used to estimate the residence time of water in the
lagoonal system (Table II).
In 1994, two separate surveys were conducted to monitor megalopal ingress at Sand
Shoal Inlet (Aug. 3-5, Aug. 15-18). These surveys were conducted immediately following neap
and spring tidal periods (42 and 72 hours, respectively). Discrete depth plankton samples were
collected from 1 and 10 meters with a 2-inch centrifugal pump and preserved in a 5% formalin
solution for later identification.
RESULTS
Residence Time of Water
The tidal prism method was used to estimate the residence time of water in the lagoonal
system (Dyer, 1976). The residence time (T) is given by:
T = (V+P)/P
where: V = low tide volume of the lagoonal system
P = intertidal volume of water
In this case, the sum of the mean volumes of water transported through the three inlets in 1993
was used as a conservative estimate of P (220.2X106 m3; Table III). The volume of water in the
lagoons below mean low water, V, was estimated using planimetry of lagoonal area and average
depths of the lagoon (872.75X106 m3; Table IV). Using these values, the residence time is
approximately 5 tidal cycles, or 60 hours.
Transport of Blue Crab Megalopae
Transport of megalopae displays a tidal periodicity, with peak abundances on night time
flood tides (Figures 2 and 3). Megalopae were generally more abundant at 10 meters than at 1
meter. Highest densities of megalopae occurred during the spring tide survey, from August 15-18,
with peak densities reaching 8-9 megalppae/m3. During this survey (August 15-18), megalopae
were collected at 10 meters during daytime flood tides and at 1 and 10 meters on ebb tides near
the end of the survey. This differs from the neap tide survey, when megalopae were generally
absent during ebb tides and during daytime flood tides. However, megalopae appear to have a
mechanism for effecting transport into the lagoons on flooding tides and avoiding export on
ebbing tides.
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DISCUSSION
The residence time of water within the lagoonal basin is of great importance to postlarvae
offish and invertebrates recruiting from coastal waters. Many invertebrates have a prerequisite
competency period before settlement and metamorphosis can occur (Burke, 1983 and references
therein). A competency period that exceeds the residence time of water within a basin places the
organism at risk of advection out of the system. In this case, megalopae advected back out of the
lagoons are at risk of predation in the water column, and lack any suitable habitat for settlement
and metamorphosis. While there is evidence that megalopae can delay metamorphosis while
offshore (Wolcott & De Vries, 1994), recruitment to the lagoons appears to cause physiological
changes that accelerate metamorphosis of megalopae (Brumbaugh & McConaugha, 1995). Thus,
blue crab megalopae appear well adapted to the relatively short residence time of water and are
able to take advantage of the shallow lagoons as a recruitment habitat.
The ingress of megalopae on nighttime flood tides appears to be a mechanism for both
avoiding predation and enhancing transport into the lagoon (Olmi, 1994). The greater abundance
of megalopae at depth is probably in response to cues received as megalopae approach the coast
from offshore (Forward & Rittschof, 1994). This differs from behavior of megalopae offshore,
where they generally occur in the upper few meters of the water column. The occurrence of
megalopae in the upper part of the water column offshore allows them to take advantage of wind-
driven coastal circulation patterns which can enhance retention within the Middle Atlantic Bight
(McConaugha, 1988). In addition, Northeast wind events can cause transport of megalopae from
offshore waters into coastal embayments (Little & Epifanio, 1991). However, changes in
behavior that occur as megalopae approach the coast may enhance retention once megalopae
reinvade coastal environments. By rising in the water column during flood tides and sinking
during ebb tides, megalopae can effect transport into lagoons and reduce the risk of advection
back to the coastal ocean (Olmi, 1994).
CONCLUSIONS
The residence time of water in the lagoonal system of Virginia's lower Eastern Shore is
approximately 5 tidal cycles, or 60 hours Laboratory studies using megalopae collected from the
lagoons show that megalopae are able to metamorphose within that time frame (Brumbaugh &
McConaugha, 1995), reducing the likelihood of advection back out of the lagoonal system on ebb
tide. Megalopae enter the lagoons primarily during nighttime flood tides, and 'are generally more
abundant at depth than at the surface, which differs from their behavior in offshore waters.
ACKNOWLEDGMENTS
This research was sponsored by the Department of Oceanography, Old Dominion
University, and by a grant from Earthwatch/Center for Field Research to R. Brumbaugh and J.
McConaugha. The help of many students and volunteers is gratefully acknowledged. The
authors especially thank Capt. Robert N. Bray, Donnie Padgett and R.C. Kidd for their time and
effort during the inlet surveys.
REFERENCES
Brumbaugh, R.D. and McConaugha, J.R. 1995. Time to metamorphosis of blue crab
Callinectes sapidus. effects of benthic macroalgae. Mar. Ecol. Prog. Ser. Accepted for
Publication.
Burke, R.D. 1983. The induction of metamorphosis of marine invertebrate larvae: stimulus
and response. Can. J. Zool. 61:1701-1719.
Dyer, K.T. 1973. Estuaries: A Physical Introduction. John Wiley and Sons, New York. 140
P
Epifanio, C.E. 1988. Dispersal strategies of two species of swimming crab on the continental
shelf adjacent to Delaware Bay. Mar. Ecol. Prog. Ser. 49: 243-248.
Forward, R.B. Jr. and Rittschof, D. 1994. Photoresponses of crab megalopae in offshore and
estuarine waters: Implications for transport. J. exp. Mar. Biol. Ecol. 182: 183-192.
Johnson, D.R. 1985. Wind-force dispersion of blue crab larvae in the middle Atlantic Bight.
Cont. Shelf Res. 4: 1-14.
Little, K.T. and Epifanio, C.E. 1991. Mechanism for the re-invasion of an estuary by two
species of brachyuran megalopae. Mar. Ecol. Prog. Ser. 68: 235-242.
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McConaugha, J.R. 1988. Export and reinvasion of larvae as regulators of estuarine decapod
populations. In: Weinstein (ed.) Larval fish and shellfish transport through inlets. Am.
Fisheries Soc. Symposium 3: 90-103.
Olmi III, E.J. 1994. Vertical migration of blue crab megalopae: Implications for transport in
estuaries. Mar. Ecol. Prog. Ser. 113: 39-54.
Orth, R.J. and van Montfrans, J. 1990. Utilization of marsh and seagrass habitats by early
stages of Callinectes sapidus. A latitudinal perspective. Bull. Mar. Sci. 46(1): 126-
144.
Weinstein, M.P. and Brooks, H.A. 1983. Comparative ecology of nekton residing in a tidal
creek and adjacent seagrass meadow: community composition and structure. Mar.
Ecol. Prog. Ser. 12: 15-27.
Wolcott, D.L. and De Vries, M.C. 1994. Offshore megalopae of Callinectes sapidus: depth of
collection, molt stage and response to estuarine cues. Mar. Ecol. Prog. Ser. 109: 157-
163.
Wong, K. -C. 1991. The effect of coastal sea level forcing on Indian River Bay and Rehoboth
Bay, Delaware. Est. Coast. Shelf Sci. 32: 213-229.
Wong, K. -C. 1986. Sea-level fluctuations in a coastal lagoon. Est. Coast. Shelf Sci. 22: 739-
752.
Wong, K. C. and DiLorenzo, J. 1988. The response of Delaware's inland bays to ocean
forcing. J. Geophys. Res. 93: 12,525-12,535.
270
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Table I. Physical characteristics of the major inlets along Virginia's lower Eastern Shore.
Depth (m)
Area (m2)
Sand Shoal
Inlet
20
9,849
Machipongo
Inlet
20
11,645
Quinby
Inlet
10
5,286
Table II. Net transport of water (X 106 m3) through the inlets over two tidal cycles in 1993.
Tidal Phase
Ebbl
Flood 1
Ebb 2
Flood 2
Net Transport
Sand Shoal
(July 12-13)
-60.8
88.5
-63.3
119.1
83.2
Machipongo
(July 15-16)
-95.9
134.7
-59.8
75.7
54.7
Quinby
(Aug. 12-13)
-53.4
43.1
-47.5
38.5
-19.3
Note: negative values indicate transport OUT of the inlet.
Table III. Mean tidal exchange (X 106 m3) through the inlets during flood and ebb tides (± 1 std.
dev.).
Sand Shoal Inlet
Machipongo Inlet
Quinby Inlet
TOTAL
83.0(27.1)
91.6(32.4)
45.6 (6.4)
220.2
Table IV. Area and volume of lagoonal system.
Channel
Subtidal Flats
TOTAL
Area
(X106m2)
45.5
243.0
Depth
(m)
8.5
2.0
Volume
(X106m3)
386.75
486.0
872.75
271
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CHESAPEAKE
BAY
ATLANTIC
OCEAN
Figure 1. Map showing study area. The lagoons along the lower Eastern Shore are
comprised of shallow basins between the Delmarva Peninsula and offshore barrier islands.
Flux studies were conducted at the three largest inlets along this section of coast: Quinby
Inlet, Great Machipongo Inlet, and Sand Shoal Inlet.
272
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Density of Blue Crab Megalopae
August 3 -5,1994
K)
•>J
<*>>
4
.Q
Flood
Ebb
Flood
Ebb
Flood
Ebb
Flood
Ebb
11
n
1700 2000
400
800 1200 1600 2200
Time
200 600 1000
1 Meter •-10 Meters
-------
to
Number of Blue Crab Megalopae
August 15 -18,1994
2000 200 800 1400 2000 200 800 1400 2000 200 800 1400
Time
1 Meter -<•-10 Meters
Figure 3. Density (#/m3) of blue crab megalopae in plankton samples at Sand Shoal Inlet, August 15-18, 1994 (spring tide
survey).
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OTOLITH BASED INDICES OF RELATIVE GROWTH RATES OF JUVENILE
ATLANTIC CROAKER AS A FUNCTION OF ENVIRONMENTAL QUALITY AND
ESTUARINE LOCATION
John S. Burke and David S. Peters
National Marine Fisheries Service
Beaufort Laboratory
Beaufort, N.C. 28516
INTRODUCTION
Otolith based indices of growth of Atlantic croaker sampled along a gradient in the heavily
contaminated Houston Ship Channel, a human-made arm of Galveston Bay TX, showed that
growth rate declined as degree of contamination increased (Burke et al., 1993). In the present
study we evaluated: 1) whether growth indices (otolith weight and increment width) were
sensitive to a range of environmental quality less severe than the range encountered in the
Houston Ship Channel and 2) whether the observed decline in relative growth rate at
progressively upstream stations in the Houston Ship Channel is characteristic of other estuaries.
MATERIALS AND METHODS
Prior to sampling we rated the quality of the sampling areas in Charleston Harbor SC, as
"fair" or "good" environments based on water quality and extent of surrounding residential and
industrial development. Assuming our perception of environmental quality is accurate differences
in growth between sampling areas were expected that corresponded to our ratings.
Sampling was conducted from a South Carolina Department of Fish and Wildlife Research
vessel and the NOAA RV Ferrell and it's small boats with 30 ft. and 25 ft. trawls. The Ashley,
Cooper and Wando Rivers of Charleston Harbor were sampled in late July and early August.
Environmental quality of the Ashley and Cooper were rated fair and the Wando River was rated
good. Atlantic croaker captured from upstream and downstream locations in each river were
measured for length and weighed. All otoliths were removed and weighed to 0.1 mg. Only 0-
group fish were used in the marginal increment and otolith weight analysis so fish whose otoliths
contained annuli were excluded. A subsample of otoliths were sectioned in the transverse plane
and polished so that increments could be observed with a light microscope. Otolith ring widths
were measured along a line perpendicular to the rings just dorsal of the sulcal groove. To prevent
reader bias mounted sections were processed in random order without knowledge of source.
RESULTS
Largest croaker were caught in the Wando and smallest in the Ashley River. Analysis of
covariance offish length otolith weight relationships indicated differences (p<0.05) between rivers
but not between upstream and downstream sites within a river. The analysis indicated that Wando
croaker had on average lighter otoliths than croaker from the Ashley suggesting faster growth in
the Wando. Smaller croaker caught in the Cooper had otoliths that were similar in weight to
croaker in the Wando but the larger sized croaker had on average heavier otoliths than the same
sized fish from the Wando. Analysis of marginal increment width data showed a similar pattern,
i.e., no statistically significant differences were found between upstream and downstream stations
within a river but croaker from upstream stations of the Ashley and Cooper Rivers had narrower
increments than fish from Wando River stations (p<0.05) suggesting faster growth in the Wando
(Table 1).
DISCUSSION
Otoliths contain a record of the growth history of a fish and their weight has been used as
an index of long term growth rate (Burke et al., 1993). Slower growing fish have heavier otoliths
than faster growing fish of the same size (Secor & Dean, 1989) allowing inference concerning the
relative growth rate of a fish and the factors that affect it (Casselman, 1990).
The differences in fish growth indices observed in our study may have resulted from
differences in water quality between the rivers sampled. Although the long term index of growth
indicated poorer growth in the rivers classified to have "fair" environmental quality, there
275
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appeared to be differences in how growth was affected in these rivers. Analysis indicated that on
average all size classes of juvenile croaker grew slower in the Ashley River than in the Wando
River while only the larger size class of croaker from the Cooper River appeared to grow slower
relative to this size class of croaker in the Wando.
Results of marginal increment analysis (short-term index of growth rate) were consistent
with those of the long-term index and with our expectations based on water quality. This might
not always be true due to short-term events that affect factors that affect growth e.g.,
temperature, dissolved oxygen, or food availability. In addition, marginal increment analysis is
time consuming and thus the index may, by necessity, be based on a small sample size (Table 1).
For studies such as this one, where an index of long-term average growth rate is required, otolith
weights may allow an effective and low cost analysis.
Comparisons of otolith weights from sites in the rivers of Charleston Harbor indicate that
slow growth of Atlantic croaker in upstream areas is not a consistent pattern of estuarine habitat.
The commonly observed decline in croaker size upstream (Miglarese et al., 1982), therefore, can
be due to downstream movement of larger fish and/or reduced growth upstream caused by
pollution (Burke et al., 1993).
REFERENCES
Burke, J.S., Peters, D.S. & P.J. Hanson. 1993. Morphological indices and otolith
microstructure of Atlantic croaker, Micropogonias undulatus, as indicators of habitat
quality along an estuarine pollution gradient. Environ. Biol. Fish. 36: 25-33.
Casselman, J.M. 1990. Growth and relative size of calcified structures offish. Trans Amer.
Fish. Soc. 119:673-688.
Miglarese, J.V., McMillan, C.W. & M.H. Shealy. 1982. Seasonal abundance of Atlantic
croaker (Micropogonias undulatus) in relation to bottom salinity and temperature in
South Carolina estuaries. Estuaries 5: 216-223.
Secor, D.H. & J.M. Dean. 1989. Somatic growth effect on the otolith-fish size relationship in
young pond-reared striped bass, Morone saxatilis. Can. J. Fish. Aquat. Sci. 46: 113-
121.
276
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Table 1. Results of marginal increment analysis (means accompanied by the same letter are not
significantly different) and water quality of areas sampled for croaker.
Otolith increment Subjective
River
Wando River
Cooper River
Ashley River
Station n
Upper 9
Lower 9
Upper 10
Lower 10
Upper 9
Lower 9
width (n)
mean(SE)
5.8(0.2) A
5. 7(0.4) A
4.5(0.4) B
5. 5(0.3) AB
4.6(0.3)8
5.6(0.4) AB
evaluation
of habitat
good
fair
fair
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MINIMIZING POLLUTION IN SHALLOW WATER HABITATS:
WATER QUALITY-BASED LAND MANAGEMENT FOR LOCAL GOVERNMENT
Wesley R. Horner, AICP
Thomas H. Cahill, PE
Joel McGuire, PE
Cahill Associates
West Chester, PA 193 82
ABSTRACT
Across the country, development in coastal areas is increasing. This wave of growth
brings with it an array of water quality problems, both point and nonpoint source in origin. Some
enlightened jurisdictions have enacted more rigorous ordinances requiring a variety of site-specific
structural Best Management Practices (BMPs) for better stormwater and wastewater
management; however, these BMPs are at best only partially effective in their removal of nonpoint
source pollutant loads. In fact, many structural stormwater BMPs remove substantially less than
50 percent of total pollutant generation. Most developments continue to be built with few if any
BMPs.
In sum, for high growth coastal areas where new development is occurring so rapidly, the
cumulative impact of pollutants becomes significant. A broader program of preventive
nonstructural actions — a Water Quality-Based Land Management Program (WQBLMP) --needs
first to be developed and then to be implemented by local governing bodies in order to minimize
pollutant production.
The Problem: Increasing Development Pressure within Coastal Watersheds
Nationwide, recent statistics have demonstrated a decided trend toward increased rates of
growth in coastal areas.
"Almost one-half of our total population now lives in coastal areas. By 2010, the coastal
population will have grown from 80,000,000 in 1960 to 127,000,000 people, an increase
of approximately 60 percent, and population density in coastal counties will be among the
highest in the Nation." (Section 6202(a) of the Coastal Zone Act Reauthorization
Amendments of 1990 as reprinted in EPA, 1993)
As demonstrated in Figure 1, the National Oceanic and Atmospheric Administration has
documented this trend, based on data from counties adjacent to coastal waters. Although county
boundaries may not include coastal drainage in its entirety (i.e., all those areas tributary to shallow
waters), the data confirms that development pressures will continue to be substantial in coastal
areas.
Furthermore, not only are rates of growth and absolute amounts of growth increasing in
coastal watershed areas, but the type of growth also is changing, translating into added water
quality impacts. Historically, coastal growth patterns have tended to be recreational and seasonal
in nature, clustered at high densities as close to the shoreline as possible. Although this
recreational dimension of coastal development does continue to increase, population growth also
is occurring in the year-round residential sector, in tandem with year-round employment growth.
The proliferation of retirees in both formal and informal retirement communities is reinforcing this
trend. This development is occurring at significantly reduced densities in more conventional
single-family subdivisions, often considerably inland from premium priced coastal real estate. In
recent Cahill Associates studies for New Jersey's Department of Environmental Protection
(NJDEP), for example, vast increases in development were documented many miles inland from
the barrier island recreational communities where development has been focused in the past.
From a water quality perspective, this reduction in density means increase in the total area
required for development, holding any specific level of population increase constant. Larger and
larger portions of coastal watersheds undergo signficant change from their natural vegetative
cover to large-scale clearing and then reestablishrnent with an artificial and chemically maintained
278
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landscape. In sum, development pressures are mounting, inefficiently consuming larger and larger
portions of coastal watershed areas.
Water Quality Impacts of Land Development
Development invariably translates into water quality problems. At the risk of
oversimplification, these problems center primarily on wastewater and stormwater. Wastewater
has long been the target of many government programs, such that at this point, most coastal
counties require at minimum secondary level treatment of sewage, to the extent that centralized
wastewater treatment is provided Although this level of treatment removes many pollutants,
including bacterial forms, nutrients such as nitrogen and phosphorus and other pollutants are not
removed (unless tertiary or advanced treatment is provided — a rarity) and are discharged into
coastal waters. New Jersey's situation is typical of many coastal states. Another unfortunate
irony of such programs to upgrade and expand wastewater treatment plants has been that their
construction (often aided by substantial federal assistance) in and of itself has induced/accelerated
additional growth, with added stormwater and wastewater pollutant loadings.
Wastewater may be treated by on-site systems such as conventional septic systems. Over
time, these systems, even if engineered and installed properly, almost without exception
malfunction and become pollutant sources. This malfunctioning occurs due to lack of proper
maintenance, because programs requiring their proper maintenance are virtually nonexistent and
few owners voluntarily pump out and otherwise properly maintain their systems. Potential for on-
site septic problems is especially great in coastal areas where in many cases soils are sandy and
therefore transmit pollutants such as nitrates out to receiving waters quite rapdily. Water tables in
these coastal settings also tend to be high, barely satisfying minimum separation requirements
from septic system seepage bed bottoms. All of these factors combined in coastal settings
increase pollution potential; if large portions of coastal watersheds come to be developed at
lowered densities with on-site septic systems, pollution can increase dramatically.
Stormwater-linked nonpoint source pollutants are generated from both impervious and
pervious surfaces, as new land development occurs. Researchers have acknowledged pollution
from impervious surfaces ~ the new roads, parking lots, and other paved or otherwise impervious
areas accompanying growth, where metals, hydrocarbons, other toxics, suspended solids, and a
variety of other pollutants are generated. Just as significant can be pollutant loadings from
pervious areas, defined as the new maintained landscape areas (including lawns), accompanying
new developments. Because of the chemical-intensive nature (fertilizers, herbicides) of so much
of this artificial landscape exacerbated by the frequently looser sandy soils (or at the other
extreme, coastal rock outcroppings), nonpoint loadings can become quite substantial. Put another
way, as more natural watershed area is converted or "consumed" by new land development,
coastal water quality deteriorates. For any fixed level of population growth, adverse water quality
impacts increase as area consumed by development increases. Therefore, reduction in land
"consumed" by new impervious and pervious areas becomes an important management objective
underlying the Water Quality-Based Land Management Program.
It is important to acknowledge that, as with wastewater treatment, advances have been
made in some coastal county jurisdictions through requiring improved Best Management Practices
for stormwater management. The problem here is that although these BMPs reduce nonpoint
source pollutant loads, their effectivenes at best is only partial. Furthermore, the vast majority of
developments in coastal counties continue to be constructed without the benefits of optimal
BMPs. It is ajso important to acknowledge that the nature and extent of the stormwater-linked
pollutant loadings have been largely ignored by the regulatory agencies; only recently has
attention been given to this pollution source. In fact, even at this writing, the vast majority of
jurisdictions — states, counties, municipalities ~ do not perform any sort of wet weather or
stormwater-based water quality sampling and therefore lack the basic data to assess the nature
and extent of stormwater-related pollutant loadings. The vast bulk of nonpoint source intelligence
has originated at EPA and other federal agencies.
In sum, increasing development pressures are translating into greater pollutant loads, both
point and nonpoint source in nature Coastal water quality is being affected. These impacts will
worsen over time as development increases.
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Water Quality-Based Land Management Principles
Land and water interrelate in many ways. Similarly, land use management and water
resources managment are linked, merging ultimately as watershed management. Because of the
interrelatness of land and water, principles designed to manage growth come to be remarkably
similar to principles designed to manage water.
Water Quality-Based Land Management is governed by a set of simple principles which
are derived from the basic understanding of the relationship between land and water and the
various ways in which land use affects water quality. These principles, in highly summarized form
below, relate both to wastewater and stormwater as discussed above:
1. Establish reasonable levels of development
2. Develop land use types which minimize required land area consumed
3. Locate concentrated development on least sensitive watershed areas
4. Make sure that watershed zones to be preserved are properly protected
5. Use optimal Best Management Practices site by site.
Water Quality-Based Land Management: From Principles to Program
Municipalities can operationalize these principles through their basic planning tools: the
comprehensive plan (including supporting functional plans), the zoning ordinance, and land
development/subdivision regulations.
Comprehensive Plan/Functional Plans/Zoning Ordinance:
As the cornerstone of municpal land management, the comprehensive plan and its
implementing zoning ordinance should first establish a reasonable level of growth and
development, both residential (population) and non-residential. This level of development should
be consistent with state, regional, and county level growth projections and plans, if available, or at
minimum reviewed by the appropriate agencies on these more macro planning levels. Clearly, the
objective here is to prevent individual municipalities from exaggerating development levels, a
tendency in those instances where municipalities believe that their fiscal futures can be guaranteed
through maximizing development and the real estate tax base (an arguable hypothesis itself). A
sprawled hodge-podge of development invariably results.
Next, this reasonable level of growth should be translated into development configurations
which minimize land area required and minimize other water resource "stressors." For example,
because variables such as "vehicle miles traveled" and "vehicle trips generated" correlate directly
with nonpoint source pollutant generation, high density development configurations in the neo-
traditional mixed use village/town mode are ideal. These configurations reduce overall reliance
on the automobile; public transportation and mass transit may even be viable options. Area
required for large road systems, expanses of vehicle parking areas, and so forth is minimized.
Assumed as part of this step is a "visioning" process, as it has come to be called by planning
theorists, where muncipal residents work to identify the end-state type of community desired.
Next, this reasonable growth level which has been translated into optimal development
configurations must be geographically distributed within the municipality. This distribution
process assumes that as part of the planning process, important resources and sensitive areas have
been properly inventoried so that "loading" of development avoids zones where water resource
and other environmental impacts would be greatest. These areas to be avoided will vary from one
municipality to another, but would include features such as floodplains, riparian zones, wetlands,
steep slopes, special habitat areas, headwaters watersheds, watersheds of recreational lakes and
water supply reservoirs, and others. This highly summarized description of the planning process
(in fact, actual planning is much more complex and cannot be detailed here) culminates in the
municipal comprehensive plan.
The comprehensive plan is directly operationalized by the municipal zoning ordinance,
which translates plan concepts into regulation and which satisfies the fourth Water Quality-Based
Land Management Principle: Make sure that watershed zones to be preserved are properly
protected. Some of this regulation may be reactive and restrictive in nature: sensitive area
overlays in zoning for protection of the floodplains and ripiarian area and wetlands and other
280
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special values and sensitive areas enumerated above (municpalities can choose among a variey of
ways to accomplish these objectives in their zoning regulations). More importantly, however,
zoning must be proactive, advocating and providing inducements to actualize reasonable levels of
growth into their optimal configurations in order to create the type of community envirsioned in
the comprehensive plan Again municipalities may choose among a variety of techniques to
accomplish their objectives in zoning, above and beyond the conventional straightforward
approach of fixed zones allowing for different uses at different intensities:
• Transfer of development rights
• Urban growth boundaries
• Clustering options, lot averaging, open space zoning
• Performance zoning, netting out, overlay zoning.
These techniques can be used in ways which allow for different degrees of flexibility with
different levels of positive and negative incentives, depending upon local preferences. The zoning
ordinance can be further structured to provide incentives through varying the application process:
applications which comply with optimum standards may be fast-tracked, for example.
A second critical mechanism for implementing the comprehensive plan is functional
planning, such as sewer/wastewater planning and water supply planning. Provision of
infrastructure by the municipality provides a powerful inducement for accomplishing the
objectives of the comprehensive plan, assuming that higher density development with
infrastructure is part of the planning.
Subdivision Regulations
The final water resources management principle — Require Best Management Practices
site by site ~ is best accomplished through the subdivision/land development ordinance. The
essential function of subdivision regulations is to manage how development occurs, after
decisions regarding how much of what type of use goes where have been answered in the
comprehensive plan and zoning ordinance. In the ideal, BMPs should be identified in a matrix
(Figure 2), setting forth techniques by different types of development in different soils, geological,
and possibly other natural features contexts. Size of parcel/size of development also may
influence BMP requirements. High priority should be given to a minimum disturbance/minimum
maintenance BMP (called "site fingerprinting" in the 6217(g) Management Measures Guidance).
Landscaping specifications should reflect both water quantity and quality objectives (i.e., utilize
native landscaping techniques where irrigation and chemical application requirements are
minimized, to the extent that re-landscpaing is required). Additionally, subdivision specifcations
for streets, curbing and other site development features must be made to be sensitive to water
resources needs. Street width reduction, curbing requirements, and a variety of other
conventional requirements should be re-evaluated from a water resources perspective.
In sum, the Water Quality-Based Land Management Program is ambitious and far-
reaching. Many other planning objectives above and beyond water resources must be integrated
into the planning process (although it should be noted that the type of growth management
concepts being advocated here bear remarkable resemblance to concepts advocated by community
planners to achieve "livable" communities, by transportation planners to minimize traffic
congestion, and so forth). Implementation by most municipalities will require time and
commitment. Difficulties notwithstanding, Water Quality-Based Land Management Program is
essential if optimal water quality is to be maintained.
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THE BALTIC MACOMA:
ABUNDANCE AND DISTRIBUTION OF AN IMPORTANT WINTER FOOD OF
DIVING DUCKS IN CHESAPEAKE BAY
Dennis G. Jorde and G. Michael Haramis
U.S. National Biological Service
Patuxent Environmental Science Center
Laurel, MD 20708-4015
INTRODUCTION
The Baltic clam (Macoma balthicd) is an abundant infaunal organism in the Chesapeake
Bay where it occurs in oligohaline, mesohaline, and polyhaline habitats. Populations of Baltic
clams in the Bay might experience large annual fluctuations. However, local distributions of
Baltic clams are influenced more by substrate conditions than by salinity.
Although of no commercial value, the Baltic clam is an important food item of aquatic and
avian predators. From previous studies we know that canvasbacks (Aythya valisnerid) and other
diving ducks use shallow water, near-shore areas to forage for Baltic clams. During winter,
certain waterfowl rely heavily on Baltic clams in shallow, near-shore areas as a primary prey base.
In prolonged periods of freezing weather, ice forces waterfowl to leave these critical foraging
sites and move to deeper water areas (e.g., shipping channels) where clams are less abundant and
more difficult to obtain. During these stressful periods when Baltic clams are limited,
canvasbacks are unable to maintain body mass and often experience increased mortality.
Poor water quality and widespread depletion of wild celery (Vallisneria americand) and
other submerged aquatic plants, which are more important and nutritious than clams as waterfowl
foods, has resulted in the continued dependence of canvasbacks on Baltic clams as their primary
winter food. Canvasbacks now feed almost exclusively (97%) on these clams. Despite this
dependence, little information exists regarding the Bay-wide distribution and abundance of Baltic
clams, and changes that occurr in Baltic clam populations over time.
METHODS
We conducted one-time, broad benthic surveys in 1990 and again in 1994 to determine the
distribution and abundance of Macoma balthica andM mitchelli in major tributaries of the upper
and middle Chesapeake Bay. In addition, between June 1991 and June 1994, we conducted local
quarterly abundance studies at 15 locations to detect changes in the Baltic clam food base.
Tributaries sampled included the Chester River south to Monie Bay on the eastern shore, and
Middle River to the Potomac River on the western shore of Maryland. We did not collect
samples along mainstem areas of the Chesapeake Bay because of time constraints and because our
core sampling device was limited to water depths of 4.5 m. We selected a 0.6 km rectangular
grid producing a sample density of 4 samples/km2. Our sampler obtained cores that were 17x17
cm in cross-section (289 cm2) and a maximum depth of 22 cm. Two cores were taken at each
sample station for a combined sample area of 578 cm2, and a theoretical low density sensitivity of
about 69 clams/m2. Clams were obtained by flushing sediment cores through a coarse 12.8 mm
and a fine 6.4 mm-mesh sieve. The 6.4 mm sieve retained all clams that were about 9 mm or
greater in length. All intact Baltic clams and M. mitchelli were counted and measured to the
nearest mm. Depth, bottom type, shellfish, submerged aquatic vegetation, and loran location also
were recorded for each sample station.
RESULTS AND DISCUSSION
Distribution
The Baltic clam had the highest frequency of occurence (56%), followed byM mitchelli
(36%). Other species of clams occurred in <14% of the 2995 sites sampled. The frequency of
occurrence of the Baltic clam was considerably less in the upper western shore (31%) compared
to >60% in the lower western and upper and lower eastern shore regions. M. mitchelli was most
common in the upper eastern shore (49%) and least common in the lower eastern shore region
(13%). The upper western region is highly urbanized compared to the less developed, agricultural
282
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landscape of the other three regions. For most of the tributaries surveyed, the Baltic clam
population was highly variable in distribution and abundance (Figure 1).
Baltic clam abundance varied from zero to a maximum of 140 clams/sample (2,422/m2);
the maximum sample was in Eastern Bay in the upper eastern region . Comparing clam
abundance of paired 1990 - 1994 sample stations, we observed no significant changes in Baltic
clam populations except for Eastern Bay (+119 clams/m2) and for the Patuxent River north of the
bridge at Benedict (- 289 clams/m2).
The West and Rhode River sampling area in the upper eastern region had the highest
average abundance ofM mitchelli (5.1 clams/sample). The maximum number of M. mitchelli
recorded was 31 (536/m2) in St. Clements Bay and the Wicomico River on the Potomac River in
the lower western region.
Clam size
Tributaries of the western regions had the greatest range in average length of Baltic clams
(12.1 - 26.4 mm) compared to the eastern regions (13.2 - 20.8 mm). A preponderance of larger
clams and few small clams indicates an older population that has had limited recent recruitment.
Such populations are influenced by seasonal changes in habitat characteristics, and might be
adversely affected by local environmental conditions (e.g., tides, freshwater input, predators, etc.).
Seasonal Changes
Every third month since June 1991, we studied seasonal changes in Baltic clam abundance
and recruitment at 15 high abundance (>500 clams/m2) sites. Histograms of clam length clearly
depict the occurrence of a new year class and depletion of older cohorts (Figure 2). Average
summer decline in Baltic clam abundance at 12 sites was 59% and ranged from -11% to -97%.
Based on clam length, younger cohorts were depleted at a higher rate. More than half of the
Baltic clam population was depleted during the summer, and spring recruitment was low.
MANAGEMENT IMPLICATIONS
Natural resource managers of waterfowl habitat need to know current distributions and
abundance of waterfowl foods and to anticipate which foods will be most important as the
Chesapeake Bay continues to improve in water quality and reestablishment of SAV. Currently,
canvasbacks are dependent on aquatic conditions that favor maximum Baltic clam growth and
recruitment. Therefore, estimates of long-term abundance and baselines of food resources are
important factors to understand canvasback and waterfowl abundance in the Bay.
The lack of information about the population dynamics ofMacoma balthica precludes our
full understanding of the ecological relationship between this clam and its predators. Highest
priority should be given to studies of demographics, including recruitment, survival, and growth
rates of Baltic clams. Information is needed relating environmental variables and growth rates,
and the timing and sources of mortality need to be better understood. Until more information
about the Baltic clam is available, current management efforts should coincide with efforts to
improve water quality, and to limit summer anoxic conditions. Most importantly, we believe there
is a need for regular monitoring at specific locations to provide an annual population index for the
Baltic clam in recognition of its importance as aquatic prey in the Chesapeake Bay.
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Harris Creek
MB Abundance
K)
00
Black Walnut \*
Point
Dover Bridge
Broad Creek
C
Cambridge*
Route 50 Bridge
Fieure 1 Distribution and abundance of Baltic clams at 508 sample stations in the Choptank River, 12 to 21 June, 1990. The
rhootank River is located in the upper eastern region of the Chesapeake Bay. Clam abundance is indicated by circle size.
Choptank River
-------
»o
00
C/3
U
fe
o
tf
w
Figure 2.
120
100
80
60
40
20
0
104
FISHING BAY
JUN 91
7980
39
24
17
11
2 2
31
6
32222
~\—i—1~
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36
SIZE (mm)
-------
N)
00
120
100
r 1
u
o
w
w
60
40
20
0
FISHING BAY
SEP 91
o
0)
CO
09
CM
in
-r-T
O
r*.
CO
-i—^r
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36
SIZE (mm)
-------
to
00
120
100
80
O 60
C/5
r - »
u
tt
§
p
FISHING BAY
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36
SIZE (mm)
-------
N)
00
00
§
3
U
W
PQ
120
100
80
60
40
0
FISHING BAY
MAR 92
CM
(O
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36
SIZE (mm)
-------
COASTAL MARINA BASINS AS POTENTIAL FISHERY HABITAT WITH SPECIAL
EMPHASIS ON NURSERY FUNCTION
M. E. Mroczka and P.W Dinwoodie
Cedar Island Marine Research Laboratory
P.O Box 181
Clinton, CT 06413
P.E. Pellegrino
Department of Biology
Southern Connecticut State University
501 Crescent St.
New Haven, CT 06515
T.A. Randall and J.K, Carlson
Department of Biology
University of Mississippi
University, MS 38677
INTRODUCTION
Marina basins are human-made, dredged habitats that are conspicuous features of coastal
ecosystems like Long Island Sound. Marinas have important recreational and economic value to
state and local communities, but their ecological contributions to coastal ecosystems are largely
unknown. The creation or expansion of marinas usually necessitates the physical alteration of
natural intertidal or shallow subtidal habitat. There is considerable environmental concern that
such habitat alteration will create dredged basins with little or no value to the adjacent coastal
ecosystem. It is therefore vitally important to the management of the coastal zone that ecological
contributions of marina basins be evaluated.
Except for a study of small boat facilities in Rhode Island (Nixon et al., 1973), there has
been little previous study of the ecology of marinas on the east coast. The most extensive study of
the West Coast was conducted in Skyline Marina (Puget Sound) by Cardwell et al., 1980.
The major purpose of this study was to evaluate the functional role of the Cedar Island
marina Basin as finfish habitat. Specific objectives were to: (1) document finfish community
structure; (2) evaluate general seasonal trends in abundance; and (3) evaluate the role of the
marina basin as primary finfish nursery habitat.
STUDY SITE
Cedar Island Marina is a 400 slip facility located in Clinton Harbor (Clinton, CT) Clinton
Harbor (Figure 1) is situated on the Connecticut Shore of Long Island Sound approximately half
way between New Haven Harbor and the mouth of the Connecticut River. The harbor receives
freshwater input from the Hammonasset, Indian and Hammock Rivers with the Hammonasset
being the most important. The marina is situated in the inner portion of Clinton Harbor which is
actually the mouth of the Hammonasset River. The mouth of the river is severely shoaled with
extensive mudflats occurring along both sides of the channel (DeSanto, 1987). Clinton Harbor
occupies approximately 400 acres and has a tidal range of 4.7 feet (U.S. Corps of Engineers,
1978).
The vertical distribution of temperature and salinity is essentially homogeneous within the
harbor with little evidence of persistent stratification. The inner and outer regions of the harbor
are separated by an unstable spit referred to as Cedar Island.
Pellegrino et al (1994) found that Cedar Island Marina Basin exhibited healthy dissolved
oxygen levels throughout the study period. Dissolved oxygen levels generally exceeded 6.0 mg/1
and never fell below the 4.0 mg/1 critical hypoxic level. Water temperatures were found to be
typical of a shallow embayment with summer temperatures ranging between 20-24 ppt with a
slight decrease occurring during the fall-winter. Water depths within the marina basin averaged
between 6-8 feet at mean low tide.
289
-------
METHODS
Finfish within the marina basin were monitored using several different sampling methods:
fish traps, beam trawl, gill net, and angling. Fish traps (1 cubic yard) were constructed of 0.5 x 1
inch vinyl coated wire mesh and placed at six stations within the marina basin. The fish trap survey
provided a qualitative profile of finfish occurrence and therefore finfish utilization of the marina
basin. The fish trap survey also allowed for general seasonal trends in species utilization to be
evaluated.
A beam trawl survey was also conducted to quantitatively monitor the distribution and
abundance of juveniles utilizing the marina. A one meter beam trawl with 6.4 mm mesh was used
to monitor three stations on a weekly basis. Immediately after capture, the trawl catch was sorted
by species and total length recorded.
RESULTS
A total of 40 finfish species .representing 27 families were collected from within the marina
basin during the study period (1989-1993) (Table 1). This assemblage represented a mix of
permanent residents, regular visitors, and occasional visitors to Long Island Sound. Some
examples of tropical southern visitors are the silver perch (Bairdiella chrysurd), spotfin
butterflyfish (Chaetodon ocellatus), small mouthed flounder (Etropus microstomus), and inshore
lizardfish (Synodusfoetens). Several boreal species, such as, the fourbeard rockling (Enchylopus
cimbrius), squirrel hake (Urophycis chuss) and white hake (Urophycis tennis) were also
represented.
Fish Trap Survey
A total of 30 species comprising 3,475 individuals were recovered from the fish trap
survey (Table 2) with numerical dominants being the oyster toadfish (Opsanus tau), cunner
(Tautogolabrus adspersus), tomcod (Microgadus tomcod), littlesculpin (Myoxocephalus aeneus),
blackfish (Tautoga onitis), white perch (Morone americand), and winter flounder (Pleuronectes
americanus).
The todfish and cunner were co-numeric dominants, with each accounting for about
16.4% of all individuals collected. They both achieved maximum abundance during spring-
summer. The tomcod accounted for 13.9% of total abundance with no obvious seasonal trends
being apparent. The little sculpin accounted for 11.7% of total abundance with maximum numbers
reported during the fall.
The following is a brief summary of seasonal trends for other numerical dominants. White
perch, an anadromous species of commercial and recreational importance, was found throughout
the study period with greatest numbers tending to occur in July and November. The white perch
consisted primarily of adults from June-November with juveniles being reported beginning in
December (Figure 2).
Blackfish were found throughout the study period with low numbers occurring during
winter months and peak numbers during August and September. The blackfish population was
dominated by adults (two-years-old plus) during June through August, and young of the year
(yoy) juveniles during September-December. The cunner was found generally throughout the
study period with highest numbers reported during June-August (Figure 2).
The winter flounder is Connecticut's most important resident commercial species (Smith et
al., 1989) and the second most sought after recreational species (MacLeod, 1988). The fish trap
survey reported winter flounder throughout the study period with numbers being highest during
summer and fall. The population was dominated by a mix of adults and juveniles. The sanddab or
windowpane occurred in greatest numbers within the marina basin during fall with peak
abundance in November (Figure 2).
Beam Trawl Survey
A total of 26 finfish species totaling 2,006 individuals (Table 3) were recovered from the
beam trawl survey with most individuals falling into the juvenile category. The overwhelming
numerical dominant was the winter flounder accounting for 75.8% of all individuals collected.
Other species recovered in the beam trawl survey, in decreasing order of abundance, were pipefish
(Syngnathusfuscush), hogchoker
290
-------
(Trinectes maculatus), little sculpin & sea robin (Prionotus spp.) and toadfish.
Nursery Function
A total of 32 juvenile sized finfish species (Table 1) were recovered from within the
marina basin. It is therefore apparent from this study that the Cedar Island Marina Basin is serving
as important finfish nursery habitat.
The most abundant juvenile species found utilizing the marina basin was the winter
flounder. The winter flounder is one of the most important commercial and recreational fishes of
the northeast. Juvenile winter flounder have been found to utilize a variety of habitats during their
first few months of life including shallow water coves and tidal marshes (Pearcy, 1962;
McCracken, 1963; Poole, 1966). Since survival and growth in the nursery habitat contributes to
variation in local recruitment (Bergmen et al, 1988), it then becomes important to describe all
potential habitats which juvenile flounders may utilize.
This study has shown the Cedar Island Marina Basin to be major habitat for juvenile
winter flounder with daily population estimates in some months exceeding 9,000. Lowest numbers
of winter flounder were found during the spring and highest numbers during summer and* fall. The
vast majority of flounder collected during this survey were less than 99 mm in total length (Figure
3). By calculating the mean number of flounder collected per sample day per season (Figure 4),
we were able to estimate year class strength. During this survey, 1992 was found to exhibit the
strongest year class and 1993 the weakest (Figure 4).
CONCLUSION
This study has shown that the Cedar Island Marina Basin is providing important finfish
habitat especially for juveniles. The marina is a complex three-dimensional system of pilings,
docks, floats, mooring lines and bulkheads that increases habitat complexity and provides the
physical structure which attracts finfish. The productive assemblage of plant and animal growth
that colonizes this physical system also provides important energy sources as well. It is apparent
that the Cedar Island Marina Basin is providing finfish with both food and refuge functions.
ACKNOWLEDGMENTS
This study was funded by Cedar Island Marina, Inc., Clinton, CT. We would like to thank
Steve Cappella and Drew Van Voorhees for their help in data collection.
291
-------
REFERENCES
Bergman, M.S. W., H.W. Van Der Veer and J.J. Zijlstra. 1988 Plaice nurseries: Effects on
Recruitment. J. Fish. Biol. 33 (Supplement A) :201-218.
Cardwell, R.D., S.J. Olsen, M.I. Carr and E.W. Sanborn. 1978 Biotic, Water Quality and
Hydrologic Characteristics of Skyline Marina in 1978 Technical Report No. 54 Wash.
Department of Fisheries. Olympia, Wash. 103pp.
DeSanto, R.S. 1987. Biogeographical Survey and Standing Crop Assessment. The Biological
Diversity, Productivity and Environmental Compatibility of a Small Boat Marina.
DeLeuw, Gather, and Co., East Hartford, CT.
MacLeod, R.E. 1988. A Study of the Recreational Fisheries in Connecticut. Federal Aid to
Sport Fishery Restoration F54R7 Annual Performance Report. State of Connecticut,
Department of Environmental Protection, Bureau of Fisheries.
McCracken, F.D. 1963 Seasonal movements of Winter Flounder, Pseudopleuronectes
americanus (Walbaum), on the Atlantic Coast. J.Fish. Res. Board Can. 20: 551-586.
Nixon, S.W., C.A. Oviatt and S.A. Northby. 1973. Ecology of Small Boat Marinas. Marine
Technical Report Series No. 5, University of Rhode Island, Kingston.
Pearcy, W.C. 1962 Ecology of an Estuarine Population of Winter Flounder
Pseudopleuronectes americanus (Walbaum) Bull. Bingham Oceanogr.Coll. 18(1): 1-78
Pellegrino P.E..M.E. Mroczka, P.W. Dinwoodie and T.A. Randall. 1994. Biological
Monitoring Program of Cedar Island Marina Basin: Diel Water Quality Survey
(March-November, 1991). Unpublished Report.
Poole, J.C. 1966 Growth and Age of Winter Flounder in Four Bays of Long Island, New
York Fish and Game Journal. 13(2): 206-220
Smith, E.M., E.G. Mariani, A.P. Petrillo, L.A. Gunn and M.S. Alexander. 1989 Principle
Fisheries of Long Island Sound, 1961-1985. Connecticut Department of Environmental
Protection. Bureau of Fisheries, marine Fisheries Program. 47pp.+ App.
U.S. Army Corps of Engineers. 1978. Clinton Harbor. Vol. I. Detailed Project Report Pratt.
Waltham, MA 60pp.
292
-------
Table 1. Total List of Fintith Species Collected from Cedar Island Marina Basin : 1989 - 1993
SPECIES
f. Engraulldae
* Ancnoa mltehUH
F. Angulllldae
* Angutfla roirrau
f. Gasterocteldae
ApcMn qvaoVacux
Gasferoswus acvteafus
F. Sclaenidae
•Bamfl*/(a chrytun
F. Clupeidae
• Brevoorria fyrannus
• Cfupea tunngus
"Pomolobus sp.
F. Serranldae
• Cenffoprfefes strfarus
• Moron* amerfcaru
* Moron* sxudfe
F. Chaetodontadae
* C/uclDoVMi ocetfafus
F. Cadlda*
• Enc/iytopus cimMui
• Mferapaifta fomcoo*
* Ufophyclt chins
* Urophycts Icnute
F. Cyprlnodontldw
Funduha *p.
F. Cobiidw
GoMosofiu bosc/
F. SyngathldM
Hlppocvnpus sp.
' SyngnMhu* fuscu*
F. Centrarehlda*
Ltpomto mxrochina
•INDICATES JUVENILE SPECIES
COMMON NAME
Bay Anchovy
American Eel
Fourspine Sticlkeback
Threespined Stickleback
Silver Perch
Menhaden
Atlantic Herring
Alewlfc. Blueback Herring
Black Seabass
White Perch
Striped Bass
Spotfin Buttrrflyflch
Fourtaeard Rockllng
Tomcod
Squirrel Hake. Ung
White Hake
KillHIsh
Naked Goby
Seahorse
Northern Pipefish
Blueglll Sunfish
UTILIZING THE MARINA BASIN
F. Pteuronectldae
•Pteuronectes americanus
F. Soteldae
•Trlnectes maculatus
F. Atherlnlda*
•Menldlamcnldla
F. Cottldae
• Myoxoce0ha/us aeneus
F. Batracholdldae
* Opsanus tau
F. Osmerldae
Osmerus monftur
r. Bothldae
• Etropus mkrostomus
' Pan/fcfKnys denrann
• Scoptfiaftnus aqvosus
F. Pholldae
PholH gunneUus
F. Pomatomldae
• Pomammu* «»/f»frtx
F. Triglldae
• Prionona ctroHma
* Prionoaa «vo
F. Rafldae
•Aa/asp.
F. Tetaodontldae
• SphaeroMe* macirfjfuj
F. Sparida*
• Sienolomui ehryseps
F. Synodonttdae
• Synodus foetons
F. Labrldae
* Taufoga oaHts
' Tiutoyoltbna adspcrsui
Winter Flounder
Hogchoker
Atlantic Sllvenlde
Grubby
Toadflsh
American Smelt
Smallmouthed flounder
Summer Flounder
Wlndowpane Flounder
Rock Gunnel
Blueflsh
Northern Searobln
Striped Searobln
Skate
Northern Puffer
Porgy
Inshore Llzardflsh
Blackflsh
Gunner
293
-------
Table 2. Hnflsh Species Collected from Fish Trap Survey of Cedar Island Marina Basin
(Numbers Represent Pooled Data from Six Stations)
SPECIES
AnguWarae-ite
ftmoarffn lyrmnim
Caltrop**,, mtrHum
C«t4»todon mff«u»
Cfupnfmnow
EmfitfopuB daiMu*
PtftdUutmp.
CirtruHiiM mijtmtu*
OoMMomifcMrt
Ijfpomlm mmnohlnm
MtnM«n*nMI«
MtoroaerfKi fantoarf
MkMun* mtwrtotnm
Mbmw •«•»/•
M)«MOM>P/I«U> mntu*
Offtnimltu
Omtiim mardix
P«NonOi)» 4MiMu>
Phfttm gamttlum
Htaantaln mwtMiui
Pamttmim attttrlx
Pomatobummp.
S0etpMh«fmu* agaMCM
S>ngn«hiM fe»u>
r«<*>g«on/««
Tmtagal^ru* tOmptnu*
Tttnntt* mmvtmlim
Uvpfitoto tonu%
TOTAL
lol SAMPLE DAV*
w
N
0
T
s
A
M
P
I
E
0
0
0
IP
1
0
0
0
0
0
0
0
0
1
3
3
0
0
18
0
0
1
0
1
0
0
1
22
0
.58
IU
0
2
3
0
0
0
4
1
0
B
31
40
3
4
27
17
0
M
0
0
3
5
19
32
1
245
F
3
0
1
1
0
0
1
0
33
37
0
103
2
0
43
0
0
78
1
8
15
0
325
121 54| 34
W ,
0
0
0
0
0
0
1
0
a
1
0
0
»
0
0
0
0
0
0
0
17
B
IP
15
0
2
0
0
0
7B
34
4
38
183
2
m
a
8
29
3B
5
97
4
824
81
IU
13
0
0
0
0
1
73
80
S
19
43
8
13
2
1
2
9
32
120
5
42B
SO
F
13
2
0
0
1
i
3B
33
2
105
2
3
n
0
0
so
4
89
18
1
374
X
W
0
0
0
2
0
0
0
16
3
0
0
0
0
1
1
0
1
1
2
0
0
27
4
SP
13
0
1
0
3
1
1
0
32
1
9
133
1
0
2
11
17
83
2
375
31
(U
22
0
18
0
0
0
1
11
10
2
3
42
1
0
1
0
72
81
0
257
23
F
3
1
13
0
0
0
20
9
0
6
0
0
3
0
24
4
0
102
W
1
0
0
0
0
2
0
0
0
0
0
0
1
0
0
0
P
7
151 4
tP
7
0
2
0
0
1
14
4
0
1
44
0
0
1
4
B
15
0
103
22
«U
C
1
C
0
0
0
52
5
0
10
28
11
0
0
0
10
24
38
0
103
24
F
C
0
C
0
0
1
42
2
0
aa
0
4
0
0
4
1
8
7
0
137
12
W
N
0
T
S
A
M
P
E
0
0
0
IP
2
(
0
0
0
0
0
0
0
0
14
3
0
28
29
1
0
0
0
0
1
3
4
11
0
99
22|
111
0
0
0
0
0
27
1
0
2
8
0
0
1
0
0
0
a
3
4
31
0
78
IS
F
0
0
0
0
0
0
0
0
29
2
0
11
0
0
0
i
0
0
9
0
1
6
18
0
81
10
115
7
3B
1
2
S
15
16
14
483
27B
17
409
570
24
11
8
281
2
16
1S7
3
91
299
58B
13
3475
431
Table 3. Flnflsh Species Collected from Beam Trawl Survey of Cedar Island Mirlna Basin
(Numbers Represent Pooled Data from Three Stations)
SPECKS
AnaUBbrort-tfa
CtntroprMra ••Mun
Omm u*iu» icidMtm
CaMManutawrf
Mppoctmput tft
MtnMimnMi
wtoZL^ricwT,
Op**iumlMl
OBiMrwmontar
PnflaMiy* cfenMun
PYM*« giWMtflM
mwmmrtM aiMrf«ii«
PamatofeiM >PL
Prfanoftixp.
S«000»fcmM mquofum
SpftjmMn mioi4*u»
SfffiflfMtfllM ftneiM
TjutoaionMte
TikmiHm mmet^atum
Oophycrf.rtoU.
TOTAL
1111
f
0
0
0
0
0
0
0
0
1
0
0
0
44
0
0
2
0
3
0
0
0
52
mo
w
0
0
0
3
0
0
0
a
0
0
0
0
IS
0
0
0
0
0
1
0
a
1HO
SP
0
0
0
0
0
0
0
0
10
0
1
0
12
2
0
9
a
7
0
4
0
1110
*u
0
0
0
0
0
0
0
0
0
1
0
1M
0
16
0
5
13
1
16
0
lit*
r
0
0
0
0
1
0
s
0
32
6
0
0
0
244
0
1
18
0
4
8
35
0
1111
W
0
0
0
0
0
0
0
0
0
0
0
1
7
0
0
0
0
21
0
2
0
171 89 1 229 1 358 1 32
11*1
»P
1
0
0
0
0
1
0
0
0
0
0
1
47
0
0
0
0
15
2
7
0
84
1lf1
SU
0
0
5
0
0
0
0
0
1
0
1
0
122
0
26
0
6
5
1
8
0
mi
p
0
0
2
0
2
0
1
0
P
0
1
0
41
0
2
0
1
10
0
0
0
182 1 72
1112
W
0
0
0
0
0
0
0
0
0
0
0
0
•
0
0
0
0
0
0
0
0
111*
«p
0
0
0
2
0
0
0
.0
1
2
0
0
4
21i
1
0
0
0
7
0
0
1
1112
«u
0
1
0
0
0
0
1
0
4
0
2
0
217
0
9
2
0
6
1
1
0
1»t2
F
0
0
0
0
0
• 0
s
0
14
0
0
0
1SI
0
0
3
0
5
0
0
0
1111
w
—
N
T
A
M
P
L
E
O
1MS
SP
0
0
0
0
0
0
0
0
1
0
0
0
f
0
0
0
0
3
0
H
IMS
•U
0
0
0
0
0
0
0
0
1
1
0
0
11
0
3
0
0
7
0
0
0
01 3081 317' 1651 0 11 27
1111
P
• o
0
0
0
1
0
1
1
0
0
0
0
47
0
4
2
1
6
0
TOTAL
1
1
7
5
4
1
13
1
88
1
6
6
1121
3
61
36
13
112
14
0 75
Ol 1
63 1 2006
i . 'i - ' 41 i Bi "' : ' '11
294
-------
Figure 1. Location of Study Site.
Figure 2. Seasonal Variation of Numerical Dominants
From Fish Trap Survey (•/• Abundance)
%
aim
«m
4
-------
Figure 3. Percent Frequency of Winter Flounder by Size Qass
SFREOUENCV
100ft
-4tmm SIZE CLASS
^FREQUENCY
100%
1*0-IMnrn SIZE CLASS
M • Mmm SIZE CLASS
^FREQUENCY
100%i
40%
30*
0%
1M - 1 Mmm SIZE CLASS
SprifiQ Sumrntr
tEMOU
Figure 4. Seasonal Variation of YOY Size Winter Flounder
(Mean # / Sample Day)
50
>- 40
LU
a. 30
w
20
Figures 3-4. 0
D 1969 IB 1990 H 1991 • 1992 E3 1993
WINTER SPRING SUMMER
FALL
296
-------
ACANTHAMOEBA (Protozoa: Acanthamoebidae) \S AN INDICATOR OF SEWAGE
POLLUTION IN BERMUDA INSHORE WATERS
Donald A. Munson
Department of Biology
Washington College
Chestertown, Maryland 21620
INTRODUCTION
The British Crown Colony of Bermuda consists of about 130 oceanic islands situated in
the Sargasso Sea about 950 km east of Cape Hatteras, North Carolina. The coral limestone
islands lie on the Bermuda Seamount. The islands have a permanent resident population of about
63,000, but about 650,000 tourists visit annually. This large number of visitors, along with the
hard impervious nature of the limestone sediments and sewage treatment facilities that are in need
of upgrading, have made sewage contamination and nutrient enrichment of inshore waters a major
concern in recent years. Several species of Gymnamoebae have been shown to be excellent
indicators of nutrient enrichment in aquatic ecosytems. In particular, cyst-forming amoebae
belonging to the genus Acanthamoeba have been found to be associated with sewage effluents
along both the Atlantic and Pacific coasts of the United states (Sawyer, 1992) and at waste
disposal sites in the open ocean (O'Malley et al., 1982; Sawyer et al., 1982). The purpose of this
investigation was to collect inshore sediments from Bermuda, to test those sediments for the
presence of temperature tolerant, potentially pathogenic species of Acanthamoeba, and to see if
the distribution of amoebae might be associated with sewage/nutrient impaction.
MATERIALS AND METHODS
During the summers of 1991, 1992 and 1994 sediments from 15 different inshore sites
were collected (Figure 1). Sampling sites included mangrove communities, freshwater and
brackish ponds, and full strength marine inshore habitats with a salinity of 35 ppt. Some of these
sites had been or were being impacted by sewage pollution, others were assumed to be relatively
free of anthropogenic influences. Sediments were collected by hand using sterile wooden tongue
depressors and were placed in sterile plastic bags. Samples were immediately stored on ice and
placed in a refrigerator upon return to the laboratory. Cultures from each sample were prepared in
triplicate, two for incubation at room temperature, and one for incubation at 38° C. Sediments
were streaked across the center of freshwater agar plates inoculated with Klebsiella pneumoniae
(ATCC 27899) as a food source as described by Sawyer and Bodammer (1983). Cultures were
examined with a Zeiss inverted phase-interference microscope. Amoebic trophozoites and cysts
were identified using a key to freshwater and soil amoebae (Page, 1988).
RESULTS AND DISCUSSION
Temperature tolerant, potentially pathogenic species of Acanthamoeba were found at 10
of the 15 (67%) sampling sites. A listing of temperature tolerant species found is given in Table 1.
A greater diversity of amoebae was present in cultures grown at room temperature, but these
results will not be discussed in this paper. The most commonly found temperature tolerant strain
was Acanthamoeba hatchetti. This species was discovered in contaminated sediments from
Baltimore Harbor and may be highly pathogenic to mice (Sawyer et al., 1977). Other temperature
tolerant species included A. castellanii, A. rhysodes, and possibly A. culbertsoni. The type strain
of A. castellanii has not been reported as being pathogenic to test mice and A. rhysodes has been
reported to be of low pathogenecity. Morphological features for cysts of A. castellanii and A.
rhysodes usually are sufficient for identifying both species, but biochemical tests employing
enzyme electro-phoresis (Nerad & Dagget, 1979) are sometimes necessary to distinguish them
from closely related strains. Strains that were identified only as Acanthamoeba sp. Group III
formed spherical or sub-spherical cysts with a thin, slightly wrinkled ectocyst walls. Pussard and
Pons (1977) recognized some of the problems inherent in identifying similar species of
Acanthamoeba solely on the basis of morphology and proposed that all species be placed in one
of three groups on the basis of cyst characteristics. Group III was proposed for spherical or sub-
spherical cysts having a thin, wrinkled ectocyst wall, such as those listed as Acanthamoeba sp.
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Group III, and includes all pathogenic strains (A. culbertsoni, A. lenticulata, A. royrebd) except
for A hatchetti.
Tobacco Bay, Hungry Bay, and Waterlot Inn Marina all are (or have been) impacted by
municipal sewage effluent. All sites have had a major sewage effluent discharge pipe empty into
associated nearshore waters. Both A. hatchetti and Acanthamoeba sp. Group III were isolated
from these sites, and strains of these amoebae have been previously reported from sewage
impacted marine and freshwater sites (Asiri et al., 1990; O'Malley et al., 1982; Sawyer et al.,
1982). The freshwater pond at the Southampton Princess resort hotel is located at the bottom of a
hill surrounded by a large expanse of a golf course that is regularly fertilized by the spraying of
sewage sludge. The water in the pond is highly eutrophic. Pembroke Marsh is directly adjacent to
a large municipal landfill, and it drains into Mill Creek. Although not associated with sewage
effluent, it probably receives significant nutrient input from the landfill refuse, especially during
storm events. Both of these latter sites provide ideal conditions for the growth of nutrient tolerant
species of Acanthamoeba. Richardson's Bay is a small body of rather stagnant water that is
poorly flushed. It is a shallow body of water and has considerable decaying plant material on its
bottom. This may account for the finding of A. hatchettijand A. rhysodes in its sediments. This
small bay is not known to be associated with any anthropogenic nutrient influences. Both
Hamilton Harbour, and St. George's Harbour are subject to major tour boat traffic. No amoebae
were found in St. George's Harbour, and one strain of Acanthamoeba sp. Group III was isolated
from Hamilton Harbour. Certainly both harbors are subject to significant boating pollution, but
Hamilton Harbour does receive Mill Creek as a tributary. This may account for the finding of
temperature tolerant Acanthamoeba in its sediments. Lover's Lake and Walsingham Pond are
bordered by mangrove communities. Very few protists and no temperature tolerant amoebae were
found in sediments from either site. The rationale for this paucity of protists is purely conjectural,
but it may be due to differing pH's associated with mangrove communities. Warwick Pond is a
brackish water pond that is not visibly influenced by any anthropogenic impacts. At the time of its
sampling it was undergoing a large red micro-algal bloom. Whether this would influence amoebic
distribution is unknown. Harrington Sound, a large body of water located near the center of
Bermuda, had in the past exhibited large algal blooms that were due to eutrophication from
adjacent land run off. However, that condition has been corrected, algal blooms are no longer
occurring, and no temperature tolerant amoebae were found in sediments from the sound. The
Church Bay sampling site expected to serve as a control site, and it did. The area is exposed to
very high energy wind and wave action, and is not associated with any known pollution. As
expected, no amoebae were associated with its sediments.
In conclusion, this study supports the concept that certain cyst-forming species of
Acanthamoeba may be useful as indicator organisms of sewage and other nutrient impacts in
aquatic ecosystems. Additionally, these organisms may prove useful as indicators of habitat
recovery as better management practices are developed for the disposal of sewage wastes.
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REFERENCES
Asiri, S. M. B. A., R. J. Chinnis, W. C. Banta. 1990. Potentially pathogenic species of
Acanthamoeba and Hartmannella (Protozoa: Amoebida) in sediment of the Potomac
River near Washington, D. C. Journal of the Helminthological Society of Washington
57: 88-90.
Nerad, T. A. and P.- M. Dagget. 1579. Starch gel electrophoresis: an effective method of
separation of pathogenic and nonpathogenic Naegleria strains. Journal of Protozoology
26:613-615.
O'Malley, M. L., D. W. Lear, W. N. Adams, J. Gaines, T. K. Sawyer, E. J. Lewis. 1982.
Microbial contamination of continental shelf sediments by wastewater. Journal Water
Pollution Control Federation 54: 1311-1317.
Page, F. C. A new key to freshwater and soil gymnamoebae with instructions for culture.
Freshwater Biological Association, The Ferry House Ambleside, Cumbria LA22 OLP,
England. 122 p.
Pussard, M. and R. Pons. 1977. Morphologic de la pario kystique et taxonomie du genre
Acanthamoeba(Protozoa, Amoebidae). Protistologica 13: 557-598.
Sawyer, T. K. 1992. Distribution of microbial agents in marine ecosystems as a consequence
of sewage disposal practices, p. 139-162. In A. Rosenfield and R. Mann (eds),
Dispersal of Living Organisms into Aquatic Ecosystems. University of Maryland
Publication. UM-SG-TS-92-04, Maryland Sea Grant College, University of Maryland,
College Park.
Sawyer, T. K. and S. M. Bodammer. 1983. Marine amoebae (Protozoa:Sarcodina) as
indicators of healthy or impacted sediments in the New York Bight Apex, p.337-352.
In I. W. Duedall, B. H. Ketchum, P K. Park, and D. R. Kester (eds.), Wastes in the
Ocean, Volume 1, Induistrial and Sewage Wastes in the Ocean. Wiley, New York.
Sawyer, T. K., E J. Lewis, M. Galasso, D. W. Lear, M. L. O'Malley, W. N. Adams, J.
Gaines. 1982. Pathogenic amoebae in ocean sediments near wastewater sludge disposal
sites. Journal Water Pollution Control Federation 54: 1318-1323.
Sawyer, T. K., G. S. Visvesvara, B. A. Harke, 1977. Pathogenic amoebas from brackish and
ocean sediments, with a description of Acanthamoeba hatchetti n. sp. Science 196:
1324-1325.
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Sampling Site
Temperature Tolerant Amoebae Found
Tobacco Bay
St. George's Harbour
Castle Harbour
Lover's Lake
Richardson's Bay
Walsingham Pond
Harrington Sound
Hungry Bay
Pembroke Marsh
Mill Creek
Hamilton Harbour
Warwick Pond
Pond on Golf Course at
Southampton Princess
Waterlot Inn Marina
Church Bay
Acanthamoeba hatchetti. Acanthamoeba sp. Group III
None
A. hatchetti. Acanthamoeba sp. Group III
None
A. hatchetti. A. rhysodes
None
None
A. hatchetti. A. castellanii. Acanthamoeba sp. Group III
A. hatchetti. Acanthamoeba sp. Group HI (two different
species, one probably A. culbertsoni)
A. hatchetti. Acanthamoeba sp. Group III
Acanthamoeba sp. Group III
None
A. hatchetti. A. castellanii. Acanthamoeba sp. Group III
A. hatchetti
None
Table 1. Temperature tolerant species of Acanthamoeba recoverd at 15 sampling sites in
Bermuda.
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BERMUDA
SL GEORGES
ISLAND
1
ATLANTIC OCEAN
IRELAND
ISLAND
CASTLE
3HARBOUR
SOMERSET!
ISLAND
5km
Figure 1 A map of Bermuda showing all the sampling sites. 1- Tobacco Bay, 2- St. George's Harbour, 3- Castle Harbour, 4-
Richardson's Bay 5- Lover's Lake, 6- Walsingham Pond, 7-Harrington Sound, 8- Hungry Bay, 9- Pembroke Marsh, 10- Mill
Creek. 11- Hamilton Harbour, 12- Warwick Pond, 13- Pond on Golf Course of the Southampton Princess Resort HoteL 14-
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THE ECOLOGICAL CONDITION OF ESTUARIES IN THE MID-ATLANTIC AND
GULF REGIONS OF THE UNITED STATES
J. Kevin Summers
U.S. Environmental Protection Agency
Environmental Research Laboratory
1 Sabine Drive
Sabine Island
Gulf Breeze, FL 32561
ABSTRACT
Estuarine and coastal ecosystems are among the most productive of ecological systems.
Historically, more than 70 percent of commercial and recreational landings offish and shellfish are
taken from estuaries (Department of Commerce, 1928-1988). Estuaries provide critical feeding,
spawning and nursery habitats, and migratory routes, for many commercially and recreationally
important fish, shellfish, birds, waterfowl, and mammals. Marshes and submersed aquatic
vegetation (SAV) that occur along shores of estuaries are particularly valuable components of
coastal ecosystems. These vegetated communities stabilize shorelines from erosion, reduce
nonpoint source pollution loadings, improve water clarity, and provide habitats for migrating
waterfowl, fish, and shellfish.
Billions of dollars have been spent to reduce pollutant loadings entering estuarine and
coastal ecosystems, with mixed results. In general, coastal pollution abatement programs have
been somewhat effective at reducing some of the impacts of conventional pollutants (i.e., excess
nutrients and organic materials) from point sources on water quality and at controlling
unacceptable production and disposal practices for most toxic chemicals. Some estuaries that
once exhibited prolonged periods of very low dissolved oxygen concentrations because of
discharge of excessive amounts of conventional pollutants, such as the lower salinity regions of
Delaware Bay, the Potomac River, and the lower Houston Ship Channel, have partially recovered.
In addition, massive releases of toxic chemicals that were associated with faulty manufacturing
processes (e.g., release of Kepone into the James River and PCBs and DDT into the Southern
California Bight) no longer occur. The release of a few persistent chemical, such as some
chlorinated hydrocarbons, has been controlled effectively by limiting their sale and production.
However, many other pollution problems, particularly the accumulation of persistent toxicants in
sediments and biota, the overenrichment of estuarine areas with nutrients and the loss of critical
habitat (e.g., SAV and wetlands), have proved to be difficult to control and correct.
The Environmental Monitoring and Assessment Program (EMAP) is designed to conduct
research to determine the best manner to estimate and monitor the condition of our Nation's
ecological resources. Specifically, EMAP is intended to respond to the growing demand for
information characterizing the condition of our environment and changes in that condition.
Simultaneous monitoring of pollutants and environmental changes should allow us to identify
likely causes of adverse changes. When fully implemented, EMAP should answer the following
questions: (1) What is the status, extent, and geographical distribution of our ecological
resources? (2) What proportions of these respurces are declining or improving? Where? At what
rate? (3) What factors are likely to be contributing to declining conditions? (4) Are pollution
control, reduction, mitigation, and prevention programs achieving overall improvement in
ecological conditions?
Monitoring activities in the Virginia (Mid-Atlantic) and Louisianian (Gulf of Mexico)
Provinces focus on measurements describing the benthic community, the fish community, water
quality, levels of sediment and tissue contamination, sediment tpxicity, wetlands extent and
condition, and seagrasses extent and condition. Estuarine monitoring is based on an EMAP-E
probability-based sampling design conducted over a 60-day period during July-September of each
year from 1990-1994.
The results of 1990-1992 monitoring in the Virginia Province show that 14 + 5% of the
sediments of the Mid-Atlantic region had biological conditions similar to known degraded sites
while 29 + 6% of the area showed undesirable conditions in relation to reduced water clarity and
the presence of marine debris. In 1991-1992, 28 + 6% of Gulf of Mexico estuarine sediments in
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the Louisianian Province displayed degraded biological conditions, as measured by benthic
community structure, and 29 + 6% of the area was characterized by reduced water clarity, the
presence of marine debris, and elevated levels offish tissue contaminants. Efforts are presently
underway to begin to evaluate the associations between degraded condition and environmental
stressors using statistical analyses.
While the benthic and societal use indices described above have been partially validated
using 1990 and 1991 data, several years of information will be required for complete validation.
The assessments based on these indices, therefore, should be considered preliminary.
Nonetheless, EMAP-Estuaries' monitoring surveys represent the first of their kind in that they use
common sampling methods over large geographic areas to estimate ecological conditions on an
spatial basis, so that overall condition can be inferred from the samples. By continuing these
measurements annually through the coming decades, the multi-agency EMAP will be able to
assess the changes or trends in ecological conditions throughout the estuaries of the United
States.. Significally, the EMAP will be able to judge, objectively, whether strategies being
employed to protect and restore the environment are effective. While continuing research is
necessary on the components of the indices described herein to ascertain their stability, accuracy
and validity, the benthic index appears promising as a summary measurement for ecological
condition. Certainly, emphasis will have to be placed on determining the cause(s) of poor
ecological condition beyond mere correlative associations. Then, ecological monitoring
programs, like EMAP, can function in concert with other research programs within EPA and
other Federal agencies to identify and solve the ecological problems facing the country today and
in the future.
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INTERTIDAL FISH ASSEMBLAGES IN THE SHEEPSCOT ESTUARY, MAINE
Maria J. Tort
Department Microbiology and Pathology
Veterinary Medicine
Cornell University
Levine Laboratory
Ithaca, NY 14853
INTRODUCTION
Estuaries serve as nurseries for many fishes. In temperate regions, estuarine areas have a
significant role as nurseries for juvenile fishes. However, nursery areas are not limited simply to
estuaries, but include nearshore coastal waters and exposed beaches (Lenanton, 1982; Lenanton
et al., 1982; Whitfield 1988; Bennett, 1989; Home & Campana, 1989). Nursery areas also include
offshore waters such as the Grand Banks and Georges Bank (Lough et al., 1989). There is
evidence that inshore and offshore waters of the Gulf of Maine could be suitable habitat for
nursery functions. The Gulf of Maine has been described as a semi-enclosed sea functioning as a
macro-estuarine environment (Uchupi, 1966; Campbell, 1986; Langton & Uzmann, 1989;
Langton & Watling, 1990).
The Gulf of Maine's glacial bathymetry, combined with its unique mixture of sediments
(Emery et al., 1965) contributes to the variety of available habitats both offshore and nearshore
that could be suitable for nursery areas. Several studies describe the assemblages of benthic and
pelagic fishes occurring in estuaries in the Gulf of Maine (Tyler, 1971, 1972; Recksiek &
McCleave, 1973; Targett & McCleave, 1974; McCleave & Fried, 1975; Hacunda, 1981;
MacDonald et al., 1984; Home & Campana, 1989; Langton & Watling, 1990; Ojeda & Dearborn,
1990; Black & Miller, 1991; Ayvazian et al., 1992). However, only few of these related to the
intertidal zone. This project aimed at contributing to the understanding of the role of intertidal
areas in estuaries as nursery areas in the Gulf of Maine. The study entailed an evaluation of the
influence of environmental factors on the distribution of intertidal fishes in the Sheepscot Estuary.
Despite a variety of complex habitats in the intertidal zone of the Gulf of Maine (e.g., bare
substrates, rocky shores, exposed beaches, vegetation beds, tidal creeks), the majority of these
habitats has not been adequately sampled to determine the use by juvenile and adult fishes. The
purpose of the present study was to examine the spatial variation in diversity and abundance of
fishes in the intertidal zone throughout the Sheepscot Estuary. The first portion, an estuary-long
study, included two objectives: first, to determine the species composition and relative abundance
by numbers and by biomass of the intertidal fishes in various locations, and second, to determine
which hydrographic and topographic features influenced species composition and relative
abundance. The second portion, a habitat-comparison study, dealt with spatial variation on a
smaller scale. One of the objectives was to determine the influence of habitat type on species
composition and relative abundance.
MATERIALS AND METHODS
A detailed description of the sampling and analytical methodology employed in the two
portions of the study has been described elsewhere (Tort, 1993). For the estuary-long study,
sampling was conducted once a month in June and July 1991, at seven stations (Figure 1). At
each station, simultaneous tows were performed using two 15m long beach seines with 6mm
mesh size to sample quantitatively two portions of substratum of approximately 200 m2. At the
time of each sample, corresponding water samples (for salinity determination) and water
temperatures were taken. Precipitation, wind, air temperature, and cloud coverage were noted.
Other local hydrographic and topographic features considered were: exposure of site to wave
action, distance from sea and aspects of prevailing wind during the summer months.
For the habitat-comparison study, sampling was limited to two stations: Upper Cross
River (8) and The Eddy (4) (Figure 1). At each station, three habitats were sampled: muddy
habitat (unvegetated sites with muddy, sandy substrate), vegetated habitat (sites with dense,
rooted, higher aquatic plants), and rocky habitat (rocky sites covered with macroalgae). Two
samples from each of the three different habitats were taken during the day and two during the
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night at ebbing tides in August and September. The muddy habitat was sampled by active beach
seining. In the rocky and vegetated areas, fixed gear techniques were used which consisted of
isolating particular sections by staking 24 m long seines. Collected fish were anesthetized and
fixed, and abiotic information was gathered for each fish sa: ole in each habitat.
Preserved fishes were identified and enumerated by ecies, and the total weight of each
species obtained. Total number, total weight, proportion, and frequency of occurrence were
calculated for each species. Details of the statistical methodology used in this study were
reported in Tort (1993). Univariate and multivariate regressions were used to determine which of
the measured abiotic variables explained most of the observed variation in species composition
and abundance. Cluster analysis was used to group sampling areas according to similarities in the
abiotic and, separately, the biotic data. Statistically significant clusters were assessed by
bootstrapping the similarity levels at which successive pairs of clusters were linked in the
hierarchy (Nemec & Brinkhurst, 1988a). The Fowlkes-Mallows statistic (Fowlkes & Mallows,
1983), a measure of the degree of similarity between two dendrograms, was used to compare
dependent dendrograms (species abundance data) with corresponding fixed covariate
dendrograms (environmental factors data).
RESULTS
In the estuary-long study, mummichog, Atlantic herring and alewife were the three most
abundant species by numbers (91%) and weights (88%) in the combined June and July data. Nine
other species were caught (Table 1). Mummichog dominated the collections in both months,
constituting 63% and 50% by numbers, and 65% and 66% by weight in June and July,
respectively. Atlantic herring comprised 28% and 15% of the catch by number and 23% and 5%
by weight in June and July respectively.
Species composition and relative abundance of the intertidal fish assemblages did not vary
much among locations. Environmental variables or combinations of environmental variables were
considered as possible contributors to the limited spatial variability observed in the biotic data.
The measured environmental variables did not seem to vary greatly across stations nor between
months. Surface-water temperature at the sampling sites ranged from 10.0 to 17.5°C in June and
11.0 to 21.0°C in July. Salinity varied only slightly over sites, ranging from 23.4 to 29.9 psu in
June and 21.6 to 30.8 psu in July. There were no significant differences in air temperature, water
temperature and salinity between the June and July samples. Cluster analysis indicated that
stations were highly similar with respect to environmental variables in both June and July
(similarity values 0.97-0.86) (Figure 2 A&C). Comparison of biotic and abiotic clusters failed to
indicate that there was a relationship between the species composition and the environmental
parameters at the sampled stations (the third linkage should be rejected) (Fowlkes- Mallows
statistic, P=0.028) (Figure 2).
In the habitat-comparison study, a total of 15,755 fishes representing 12 species
comprised the catch from August, early and late September. Atlantic silverside constituted 67%
by number and 70% by weight of the combined catches. Mummichog, dominating in June and
July, contributed only 15% in numbers and 12% in weight. Only alewife and Atlantic herring of
the other 10 species contributed more than 1% each to the total numbers and total weight of the
catches Differences in the abundance and biomass patterns among habitats are apparent. Many
more fishes were caught in the mud (7,323) and vegetation (8,014) than in the rocky habitat (431)
largely due to the smaller sampled area in the rocky habitat. An analogous trend is observed in
the corresponding total weights (Table 2).
Eleven species were represented in the mud habitat, eight in the rocky habitat, and 10 in
the vegetation. Atlantic silverside dominated the catches in both the muddy and vegetated
habitats Alewife and Atlantic herring were the next most common species in the mud habitat.
Mummichog and alewife were the next most common species in the vegetation. Mummichog
dominated the rocky habitat. The next most common species in the rocky habitat were Atlantic
tomcod, winter flounder and alewife. American eels were only present in the vegetation and
rainbow smelt only in the mud samples (Table 2).
The surface temperature at stations 8 and 4 ranged from 14 to 20°C in August. At station
4, in early September, the surface temperature ranged between 13.2 and 18°C, and in late
September, between 13 and 14°C.- Salinity ranges were 28.3-30.3 psu in August, 27.4-30.6 psu
305
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in early September, and 28.6-29.7 psu in late September. Paired-t tests were performed to
evaluate the differences in abiotic data between August and early September, and early and late
September. Air temperature and salinity were significantly different between the sampling in
August and early September. Air temperature was significantly different between the early and
late September sampling.
The clustering of the environmental data for station 8 indicates that the mud-night samples
were significantly different from all other samples (Figure 3 A) (temporal variablity data has been
discussed in Tort, 1993). The corresponding biotic data dendrogram also showed a separation
between the mud samples and the combined vegetation and rocky habitat samples (Figure 3B).
The comparison of the abiotic and biotic data matrices indicate that the two dendrograms
resemble one another (Fowles-Mallows statistic, P>0.15). The fact that the species composition
in the muddy habitat is different from the one in the vegetated and rocky habitats is probably not a
reflection of the difference in measured environmental conditions between the muddy and
vegetated/rocky habitats. The difference may be more due to preferences of fishes for certain
habitats. In the combined (August, early and late September) biotic data matrix for station 4,
there is no statistically significant clustering formed. However, the rock samples largely separated
from the mud and vegetation samples (Figure 4B). The comparison of the abiotic and biotic
dendrograms suggests that the statistically significant difference (P=0.040) between these two
clusters (at the three-cluster level) is other than from random variation.
DISCUSSION
The ichthyofauna of the Sheepscot Estuary from June to late September 1991 was
characterized by the dominance of mummichog, Atlantic herring and alewife in the estuary-long
study and Atlantic silverside, mummichog, and alewife in the habitat-comparison study. Targett
and McCleave (1974) reported these species as four of the most common ones occurring in the
northern part of nearby Montsweag Bay. The distributions of juvenile fish species at the different
stations of the Sheepscot Estuary are probably determined by population responses to
environmental gradients in local conditions. The estuarine community structure may be
determined primarily by responses to environmental gradients (Boesch, 1977; Weinstein et al.,
1980; Peterson & Ross, 1991; Rakocinski et al., 1992).
Multivariate regressions and cluster analysis show that different species of juvenile fishes
respond to different abiotic factors or different combinations of abiotic factors resulting in
different habitat preferences. The comparison of biotic and environmental data clusters for June
indicate heterogeneous communities. However, the corresponding comparison for the month of
July identified a similar underlying structure in both the abiotic and abundance cluster data. The
cluster analysis indicated a lack of fidelity of species to stations grouped by environmental
variables. This result may be due to the limited gradient of environmental variables measured
over the length of the Sheepscot Estuary, which would inevitably lessen the contrast between the
euryhaline and mesohaline estuarine environments.
The existence of heterogeneous communities suggests that different fish assemblages
represent species-specific differences in habitat preference and use. In the habitat-comparison, a
number of trends denote different patterns in habitat preference. Atlantic herring and bluefish
were only found in the mud habitat. The proportions of alewife and Atlantic herring were greater
in the mud habitat than in the rocky and vegetated habitats. The community in the rocky habitat
exhibited a higher proportion of mummichog, winter flounder and Atlantic tomcod than in the
vegetated and mud habitats. The relative abundance of species in the different habitats also
suggests the species-specific nature of habitat usage.
Abundances also point to the relative importance of the different habitats to different
species of juvenile fishes. The high relative abundance of individuals and species entering the
vegetated habitat demonstrates the importance of this habitat to nearshore fish communities. A
number of studies have also found that vegetated areas provide a preferred habitat for small fishes
(Orth, 1977; Thayer et al., 1975; Orth & Heck, 1980; Lubbers et al., 1990; Sogard & Able, 1991;
Rackosinski et al., 1992). The area sampled in the rocky habitat was the smallest, so the
abundances do not necessarily reflect the importance of this habitat to juvenile fishes.
Species diversity of fishes in vegetated areas is often greater than in nearby unvegetated
areas (Orth & Heck, 1980; Young, 1981; Robertson & Duke, 1987; Humphries et al., 1992).
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Similar observations of rocky habitats are limited in the literature. Arruda (1990) observed that
areas on the Portuguese coast formed by rocky pools and interstices among the boulders were
characterized by a high number offish species. The increase in the number of species in vegetated
(Pollard, 1984, Bell & Westoby, 1986, Sogard et al., 1987; Lubbers et al., 1990; Humphries et al.,
1992) and rocky habitats can be attributed to the increased habitat complexity. The complexity of
the habitat may be important for resource and refuge availability (Pollard, 1984; Thayer &
Chester, 1989; Humphries et al., 1992).
Both the vegetated and rocky habitat areas provide greater habitat complexity, thus
increasing the patterns of micro-habitat use by juvenile fishes. Juvenile fishes will then be more
abundant in some habitats rather than in others (Morris, 1987). The proportions of individual
species present in the three habitats were different. This non-uniform distribution may elevate the
importance of a particular habitat for a particular species. For instance, winter flounder, a
recreationally and commercially important species, was the second most abundant species in the
rocky habitat, but it was less important in the muddy and vegetated habitats (Table 2). The
overall proportions of species may be different because of the presence of three kinds of habitats
within close proximity.
Despite the biases introduced in the study (i.e., different sampling techniques used in
different habitats, high tow variability, etc.), the species composition and abundance results show
that all three habitats harbor significant populations of juvenile fishes. A full characterization of
fish communities requires examination of nearshore, nearbottom, vegetated and rocky areas
among other difficult-to-sample habitats (Weinstein et al., 1980; Boehlert & Mundy, 1987).
Many of these complex habitats require novel sampling methods. Techniques of sampling in the
rocky and vegetated habitats could become an important tool in the management of coastal
wetlands as part of the process to evaluate the nursery function of these environments (Olney &
Boehlert, 1988, Kneib, 1991).
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U)
o
00
TABLE 1. Species of fishes occurring in the intertidal zone in an estuary-long study of the Sheep*cot Estuary, Maine in June and
July 1991, ranked by numerical abundance. Occurrence indicates the number of tows in which each species was present in a total of 58
tows. Proportion is the fraction of the total number or total weight represented by a species. Mean densities and standard
deviations (numbers per m1) were calculated only for those samples in which the species occurred.
Species
rundulua heteroclitua
Clupaa haranaus
Aloaa, paaudoharenaua
Manidia manidia
Oaataroateus aculaatus
Miorooadiia tomcod
Urophvoia tanuls
Apaltea quadracua
Punnitius punoitius
Liopentta putnami
Alosa aastivalis
Paeudoplauronactaa americunua
Total
Common name
Hummlohog
Atlantic herring
Alewife
Atlantic silvarside
Threespine stickleback
Atlantic tomcod
White hake
Pourspine stickleback
Ninaspine stickleback
Smooth flounder
Blueback herring
Winter flounder
i
Occurrence
40
15
17
13
15
9
5
4
13
8
1
2
Number
4,562
1,782
1,560
284
144
104
64
60
43
35
3
2
8.643
Abundance
Proportion
0.528
0.206
0.180
0.033
0.017
0.012
0.007
0.007
0.005
0.004
0.000
0.000
Density
0.356
0.174
0.143
0.034
0.015
0.018
0.020
0.023
0.005
0.007
0.005
0.002
Bion
Height (g)
10,142
2,415
1,303
1,442
122
75
71
49
40
51
13
2
15,725
ass
Proportion
0.605
0.146
0.138
0.086
0.007
0.004
0.004
0.003
0.002
0.003
0.001
0.000
-------
TABLE 2. Species of fishes occurring in the noddy, rocky and vegetated habitats at
stations 4 and 8 in August and September 1991, ranked by numerical abundance.
Occurrence indicates the number of tows in which each species was present in a total
of 12 tows in each habitat. Proportion is the fraction of the total number or total
weight for each habitat represented by a species.
Abundance
Species
Atlantic silverside
Alewife
Atlantic herring
Mummichog
Winter flounder
Bluefish1
Rainbow smelt2
Threespine stickleback
Ninespine stickleback
Atlantic tomcad
Atlantic menhaden1
Total
Mummichog
Winter flounder
Atlantic tomcod
Alewife
Atlantic silverside
Rainbow smelt
Ninespine stickleback
Total
Occurrence Number
MUD
12 4,922
11 1,317
4 920
4 59
10 32
3 26
4 25
4 13
3 6
2 2
1 1
7,323
ROCK
11 337
7 32
5 22
1 21
5 14
3 4
1 1
431
Proportion
0.672
0.180
0.126
0.008
0.004
0.003
0.003
0.002
0.002
0.001
0.000
0.782
0.074
0.051
0.049
0.032
0.009
0.002
Biomass
Weight (g)
14,902
3,579
1,158
268
55
77
39
8
4
19
244
20,353
894
104
370
30
41
4
1
1,444
Proportion
0.732
0.176
0.057
0.013
0.003
0.004
0.002
0.000
0.000
0.001
0.012
0.620
0.072
0.256
0.020
0.028
0.003
0.000
309
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VEGETATION
Atlantic silverside
Mummichog
Alewife
Threespine stickleback
Atlantic tomcod
Winter flounder
American eel4
Kinespine stickleback
Rainbow smelt
Total
9
12
6
3
3
4
2
2
1
5,654
2,121
148
39
23
22
3
3
1
8,014
0.706
0.265
0.018
0.005
0.003
0.003
0.000
0.000
0.000
16,907
4,402
357
24
685
34
847
3
2
23,261
0.727
O.f89
0.015
0.001
0.029
0.001
0.036
0.000
0.000
'Pomatomus saltatrix
'Osmerus mordax
'Brevoortia tvrannus
'Anquilla rostrata
Table 3
310
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4 4« 04'
44«N-
43«55'
43«50-
43«471-
6 9* 44'
69*4O*W
69*36-
Figure 1. Locations of sampling sites in the Sheepscot River Estuary, Maine. Estuary-long
study sites are 1 through 7. Habitat-comparison sites are 4 and 8.
311
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B
• Station 2
• Station 3
• Station 5
Station 7
Station 6
Station 4
I—
0.0
0.2
0.4
0.6
0.8
Similarity
— Station 1
— Station 2
— Station 3
'— Station 4
r— Station 5
JT*— Station 7
' Station 6
Station 1
Station 2
— Station 3
Station 5
1 Station 7
Station 4
Station 6
•H
1.0
Figure 2. Dendrograms derived from the (UPGMA, Bray-Curtis) cluster analysis of the
abiotic data matrices (A and C) and the species abundance matrices (B and D) from the
estuary-long study for June and July, 1991. Asterisks indicate similarity linkages rejected
with P-cO.05.
312
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MudN
RockN
Vegetation N
MudO
RockD
Vegetation D
B
-MudN
•MudD
•Vegetation N
•RockN
•RockD
• Vegetation D
0.0
0.2
0.4 0.6
Similarity
0.8
1.0
Figure 3. Dendrograms derived from the (UPGMA, Bray-Curtis) cluster analysis of the
abiotic data matrix (A) and the species abundance matrix (B) from the habitat-comparison
study at station 8 for August 1991. Day samples are represented by a "D" and night samples
by a "N" following the habitat denominations. Asterisks indicate similarity linkages rejected
withP^O.05.
313
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,-Mudl D
P- - Vegetation 1 0
. Rodcl 0
r Mud 20
_ . Rock 2 0
. Vegetation 2 0
r-Mud2N
Vegetation 2 N
. Rock 2 N
r- Mud 3 N
Rock 3 N
. Vegetation 3 N
-Mud2N
-Mud 1 0
- Vegetation 2 N
- Mud 2 D
- Mud 3 N
- Vegetation 2 0
- Vegetation 1 0
. Rock 2 0
- Rodcl 0
• Rock 2 N
• Rock 3 N
• Vegetation 3 N
fr-
0.0
0.2
0.4
0.6
0.8
Similarity
1.0
Figure 4. Dendrograms derived from the (UPGMA, Bray-Curtis) cluster analysis of the
abiotic data matrix (A) and the species abundance matrix (B) from the habitat-comparison
study at station 4 for August (1), early September (2), and late September (3) 1991. Day
samples are represented by a "D" and night samples by a "N" following the habitat and
sampling time denominations. Asterisks indicate similarity linkages rejected with P<0.05.
314
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A COOPERATIVE RESEARCH PROGRAM BETWEN THE US NAVAL ACADEMY
AND THE US ENVIRONMENTAL PROTECTION AGENCY
Mario E. C. Vieira
Oceanography Department
US Naval Academy
Annapolis, MD 21402-5026
ABSTRACT
The Oceanography Department at the US Naval Academy (USNA) has embarked on a
cooperative research program with the US Environmental Protection Agency (USEPA). The
objective was to study the oxygen dynamics of the Severn River, a small tributary of the
Chesapeake Bay, while providing an opportunity for USNA faculty and student involvement. A
mooring was maintained between August and November 1994 near the mouth of the river. The
system was equipped with a SeaBird CTD (with added oxygen and PH sensors) and two S-4
InterOcean current meters with conductivity and temperature capability.
It was the first time that a comprehensive set of oceanographic measurements was taken in
the Severn River. Midshipmen from the USNA were involved in the project and are participating
in the analysis of the data A preliminary assessment of the data collected is presented. The
Severn River Estuary was determined to be a partially mixed estuary subjected to a classical
estuarine circulation. It was classified as a Type 2b estuary according to the Hansen and Rattray
criterion.
It is expected that an understanding of the dynamics of the Severn River will allow the
development of appropriate management measures by the USEPA.
This joint project constitutes a small scale paradigm of converging interests, inter-agency
cooperation, and maximizing of resources.
INTRODUCTION
A mooring was maintained for 97 days in the Severn River estuary, close to its confluence
with the Chesapeake Bay (Figure 1 and 2), in 8 meters of depth. The system consisted of two
InterOcean S4 current meters equipped with conductivity and temperature sensors and a pumped
through SeaBird SBE-16 CTD equipped with oxygen and pH sensors. Buoyancy was established
with a surface buoy provided by the USEPA, equipped with a VHP modem transmitter and
hardwired to the SeaBird sensors The receiving station at the Annapolis USEPA office picked
up the telemetered data. All instruments were programmed to take measurements at 20 minute
intervals.
The USEPA provided the telemetering buoy, the SeaBird and technical assistance; the
USNA provided the current meters and the mooring hardware, executed the deployment and
retrieval and maintained the system. Midshipmen from the USNA dove every week to ckeck out
the mooring and clean the sensors from biofouling.
It had been hoped to have the mooring in place in May in order to document the
stratification and onset of hypoxia/anoxia. The deployment had to be delayed to late Summer; the
mooring provided data from 17 August to 21 November 1994. The CTD and oxygen and pH
data, due to problems with the electronics, were not fit for analysis.
What follows is a preliminary analysis of the circulation and density data.
CURRENT DATA
The current meters were installed respectively 2 meters (EOT) and 5 meters (TOP) above
the bottom. Figure 3 is a cross section of the Severn from Triton Point on the south shore to
Dungan Basin on the north shore taken to include the site of the mooring. The mooring was
placed just to the north side of the channel, in water of 8 meters in depth.
The polar plot for the top instrument (Figure 4) reveals the clearly unidirectional nature of
the flow: mean flood current towards 310° and mean ebb current towards 130°. This is to be
expected in a laterally constrained tidal flow such as this one. The bottom instrument (Figure 4),
however, indicated a very diffuse pattern in the flow, albeit of much larger magnitude than at the
top. the progressive vector diagrams (Figure 5) show residual flows as expected in a classical
315
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estuarine circulation: outflow in the upper layer and inflow in the lower layer. This is consistent
with the circulation expected in the Severn, a small tributary of the Chesapeake Bay, in late
Summer and Fall when salinities are high in the main stem of the Bay.
The time series of current in the North-South and East-West directions (Figure 6) show,
aside from the semi-diurnal tidal cycles, a modest residual component. The magnitude of the
current in the bottom layer is higher than in the top layer; this is consistent with a smaller bottom
cross-sectional area and the need to conserve volume in the long term flow. The relationship
between the residual component of the circulation and meteorological forcing will be the object of
future study.
STRATIFICATION
An examination of the temperature time series (Figure 7) clearly shows the lack of a
vertical gradient. In terms of temperature the water column is thus quite homogeneous. The time
series of salinity (Figure 8), however, show overall higher values for the bottom layer as
compared to the top layer. This is consistent, once again, with the classical estuarine circulation
already detected through the current regime.
The difference in salinity between the two levels was computed and taken as an index of
the stratification (Figure 9). This is no substitute for the Richardson number, but is appropriate
for a quick look at the situation. It might be anticipated to see a decline in the stratification as the
Summer progressed into Fall. This tendency is apparent in Figure 9. Exceptions are the initial 2
weeks (second half of August) and the last 2 weeks (mid-November). The reason for these
exceptions may be related to meteorological forcing and will be the subject of future
investigations.
CONCLUSION
Utilizing the salinity and current measurements an attempt was made to classify the Severn
River Estuary according to the Hansen and Rattray criterion. This calls for a stratification
parameter defined as the ratio of the surface to bottom difference in salinity divided by the mean
cross-sectional salinity and also a circulation parameter, the ratio of the net surface current to the
mean cross-sectional velocity. The circulation parameter expresses the ratio between a measure
of the mean freshwater flow plus the flow of water mixed into it by entrainment or eddy diffusion,
to the river flow.
Time averages over the 97 days of the records were determined for the top current, cross
sectionally averaged current and salinity and top and bottom layer salinities. Upon placement on
the Hansen and Rattray diagram (Figure 10) these parameters determine a Type 2b estuary:
partially mixed with appreciable stratification. It is planned to continue the deployment of the
system in the spring of 1995 and document the evolution of the stratification and oxygen
concentration throughout the summer.
ACKNOWLEDGMENTS
This investigation results from an agreement between the USEPA and the USNA. I am
grateful to Dr. Kent Mountford, from the USEPA, for the excellent cooperation and technical
help provided. I am also indebted to the numerous midshipmen from the US Naval Academy
Oceanography and Scuba Clubs, particularly MIDN David Moore, whose interest and dedication
to the project guaranteed its success.
REFERENCES
Hansen, D.V. and Rattray, M. Jr., 1966. New dimensions in estuary classification.
Limnol Oceanog., 11, 319-326A COOPERATIVE RESEARCH PROGRAM BETWEEN
THE US NAVAL ACADEMY AND THE US ENVIRONMENTAL PROTECTION
AGENCY
316
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u>
-------
Marine Engineering Laboratory
318
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2-D Transect
Triton Point to North Shore
Triton Point
North Shore
Mooring (8m)
0 50 100 150 200 250 300 350 400 450 500 550 600
25 75 125 175 225 275 325 375 425 475 525 575
Length (meters)
Figure 3
-------
Z70
SO Z70
Figure 4. Polar Plots
-------
U)
P
r
o
g
r
e
s
s
1
u
e
U
e
c
t
o
r
N
o
r
t
h
TOP
p
r
o
g
r
e
s
s
1
v
e
U
e
c
t
o
r
N
o
r
t
h
3OT
OM
Figure 5. Progressive Vector Plots
-------
48.B
TOP
BOTTOM
•tt.B
EAST-WEST
-78.B
8/17/94 12:00:08
DAYS
6919.8
11/21/94 12:00:88
8/17x94 12:88:08
DAYS
6919.0
11/21x94 12:00:08
Figure 6. Current Velocity Components
322
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Z7.ee
T deg.C
ii.ee
8/17/94 12:Be:Oe
DAYS
6919.
11/Z1/94 12:BO:ee
Figure 7. Temperature (deg. C)
323
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s
a
1
i
n
i
t
y
S
a
1
i
n
i
t
y
11.e
4.0
8/17/94 12:00:00
DAYS
6919.0
11/21/94 12:00:00
Figure 8. Salinity
324
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co 3
£ 2
Ul
K)
0)
Q 1
0
-1
-2
Salinity Difference
0 1000 2000 3000 4000 5000 6000 7000
TIME (20 MINUTE INTERVALS)
Figure 9
-------
HANSEN and RATTRAY DIAGRAM
Figure 10
326
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EFFECTS OF BULKHEADS MADE OF PRESSURE-TREATED WOOD AND OTHER
MATERIALS ON SHALLOW WATER BENTHOS IN ESTUARIES
Judith S. Weis
Dept. of Biological Sciences
Rutgers University, Newark NJ 07102
Peddrick Weis
Dept. of Anatomy
Cell Biology and Injury Science
NJ Medical School
Newark, NJ 07103
Chromated copper arsenate (CCA)-treated wood is used extensively for pilings and
bulkheads in aquatic systems in the US and elsewhere. Wood for marine uses is generally treated
with 2.5 Ibs. per cubic foot of a mixture of chromium, copper and arsenic oxides. Some of the
metals leach from the wood (Warner & Solomon, 1990; Sanders et al., 1994), and can have
effects on biota. The actual impact of CCA wood in an estuary depends of the amount of
chemicals leached (dependent on surface area of leaching wood and on leaching rate), metal
speciation, rate of uptake by the epibiota which grow directly on the wood (determined by the
particular species and their density), the degree of dilution and dispersion by water movements,
adsorption by sediments (determined primarily by particle sizes), uptake by benthos from the
sediments, and trophic transfer from benthos or epibiota to grazers and predators. We have
previously found effects on the epibiotic, or "fouling" community, in terms of reduced growth,
reduced community diversity, and bioaccumulation of the chemicals leached (Weis & Weis, 1992,
1993, 1994; Weis et al., 1993). Previous benthic studies (Weis & Weis, 1994) showed that right
by treated wood bulkheads, the organisms had elevated levels of the three metals, and showed
reduced species richness, community diversity, and numbers of individuals.
The current studies were performed in order to investigate the spatial extent of effects,
i.e., how far away from a bulkhead effects could be ascertained. These studies include three types
of analyses: chemical analyses of the fine particle fraction of the sediments (by atomic absorption
spectrophotometry) for Cu, Cr, and As, chemical analysis of bioaccumulation of these metals by
benthic organisms, and the community structure along a transect at 0, 1,3, and 10 m from the
bulkhead. We have measured these parameters at a number of bulkheads made of CCA wood and
at bulkheads constructed of other materials. We present here the data for a CCA bulkhead in
Middle Pond, a subestuary of Shinnecock Bay in Southampton, NY. The bulkhead, which was in
an open area but did not have extensive tidal flushing, was one year old. An unbulkheaded
reference site was chosen so that other factors would be equivalent at the two sites. An additional
reference site was an aluminum bulkhead in nearby Bullhead Bay, from which a similar transect
was made
Data are seen in Table 1. In the fine fraction, concentrations of Cu, Cr, and As were
highest at 0 m, decreased steeply between 0 and 1 m, then slowly decreased to 10m. The
reference site had generally low concentrations of the three contaminants, comparable to the 3 m
site The Bullhead Bay (aluminum bulkhead) sediments metal levels were low, and did not show a
gradient from 0 - 10m, although there is anomalously high copper at 0 m. The highest
concentrations of the three contaminants were seen in organisms in Middle Pond (primarily
Neanthes) collected at the 0 site, adjacent to the CCA bulkhead. Concentrations were much lower
in organisms at 1 and 3 m from the wood However, in organisms 10 m away (where sediments
had low concentrations in the fines, but greater amounts of fines) the organisms showed a
consistent increase in tissue metals, although, due to the low number of replicate samples and high
variance, this increase was not always statistically significant. ANOVA followed by Bonferroni
multiple comparison tests for Cu showed F = 2.26; there were two groups within which the
differences were not significant: 0 > all others. For Cr, no differences were found. For As, F =
30.01 indicating significant differences. Bonferroni gave three groups: 0 > 10 > 1, 3, and ref.
The dominant organisms in samples taken by the CCA bulkhead and reference site in
Middle Pond were the polychaetes Scolecolepides viridis, Haploscoloplos sp., Neanthes spp.,
327
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Clymenella torquada, and Capitellids, as well as the snail Ilyamssa
were abundant at Bullhead Bay, as was the amphipod Leptocheirus sp.
richness at the different sites are in Table 1. ANOVA (df 4 between, 20 within) »n^te
significant differences (F = 10 66 P = 0.0001). Bonferroni showed two groups within wnicn me
means were not significantly different' 0,-1, and 10 m< 10 m, 3 m, and reference site. Iftus, tne
species richness was lowest atO and 1 m, intermediate at 10 m, and highest at: 3 m and tne
reference site. Within the 0-10 m transect from the aluminum bulkhead at Bullhead Bay Were
were no significant differences in species richness among the sites (ANOVA - 3 df between 10
within, F = 2.79, P > 0.05) The Shannon-Wiener diversity index is seen in Table 1. Kruskal-
Wallis and Mann-Whitney U tests revealed that at Middle Pond there were three groups which
were significantly different from each other: Oandlm<10m<3mand reference site. Thus the
lowest diversity was at 0 and 1 m, 10 m was intermediate, and 3m and the reference site had the
highest diversity. Within the 0 - 10 m transect at the Bullhead Bay aluminum bulkhead, the
diversity index was not significantly different among the sites (F = 1.14).
The biomass is seen in Table 1. ANOVA followed by Bonferroni showed two groups in
Middle Pond within which the means were not significantly different: 0,1, and 10 m < 3 m, 10 m
and reference. Thus, in terms of biomass, the 0 and 1 m sites were lowest, 10 m intermediate, and
3 m and reference highest Within the 0 -10 m transect from the aluminum bulkhead at Bullhead
Bay there were no significant differences among the sites (ANOVA F = 0.82).
Accumulations in Middle Pond organisms were greatest in organisms living immediately
adjacent to the wood. Tissue concentrations in biota decreased significantly from 0-3 m, but rose
consistently, but not significantly, at 10 m, where the amount of fines in the sediments had
increased considerably. The small number of replicates was probably responsible for the lack of
statistical significance. The community structure characteristics correlated well with the rising
contaminant levels in the animals at 10 m. Species richness, diversity, and biomass were lowest
immediately by the wood, increased out to 3 m, but decreased (significantly) again at 10 m. These
patterns of community structure were not seen in a similar transect from the aluminum bulkhead
in Bullhead Bay. The finding that the bipaccumulation and effects are greatest immediately
adjacent to the CCA wood indicates a high bioavailability of the contaminants from this 99%
sandy sediment, whose overall contaminant level is quite low, although the 1% fines are highly
contaminated. This is in keeping with findings of Rule and Alden (1990) indicating greater
bioavailability of metals from sandy sediments. Organisms are interacting with (ingesting) the fine
fraction of the sediments. Since they are largely deposit feeders, they are seeking out the fine
fraction, even when it is rare, and thereby acquiring a high body burden. Most of the polychaetes
collected are sessile deposit-feeding tube dwellers except for the Nereids. There was not a
comparable reduction in the benthic community adjacent to the aluminum bulkhead, making it
likely that the reduction in Middle Pond was due to chemicals leached from the wood, rather than
the physical effects caused by the presence of the hard structure.
In other bulkheaded areas we have analyzed, it has become clear that the benthic effects of
the CCA wood leachates are greatest by new wood structures and in areas that are poorly flushed.
We have analyzed sediments, organisms, and community structure in a number of areas with CCA
dock pilings, rather than bulkheads, and have not seen any significant effects from these structures
which provide much less surface area for leaching than do bulkheads. This is in agreement with
studies by Wendt et al., 1994.
328
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REFERENCES
Rule, J. H. and R W. Alden III. 1990. Cadmium bioavailability to three estuarine animals in
relation to geochemical fractions of sediments. Archives of Environmental Contamination
and Toxicology 19: 878-885.
Sanders, J G., G. F. Riedel and R. W. Osman. 1994. Arsenic eye g and its impact in
estuarine and coastal marine ecosystems. In: J. Nriagu, ed. Arsenic in the
Environment. Part 1. Cycling and Characterization. John Wiley & Sons, New York, pp
289-308.
Warner, J. E. and K. R. Solomon. 1990. Acidity as a factor in leaching of copper, chromium,
and arsenic from CCA-treated dimension lumber. Environmental Toxicology and
Chemistry 9: 1331-1337.
Weis, J. S. and P Weis. 1992a. Transfer of contaminants from CCA-treated lumber to aquatic
biota. Journal of Experimental Marine Biology and Ecology 1561: 189-199.
Weis, J. S. and P Weis. 1992b. Construction materials in estuaries: reduction in the epibiotic
community on chromated copper arsenate (CCA) treated wood. Marine Ecology
Progress Series 83: 45-53.
Weis, J. S. and P. Weis. 1993. Trophic transfer of contaminants from organisms living by
chromated-copper-arsenate (CCA)-treated wood to their predators. Journal of
Experimental Marine Biology and Ecology 168: 25- 34.
Weis, J. S. and P. Weis. 1994. Effects of contaminants from chromated copper arsenate- treated
lumber on benthos. Archives of Environmental Contamination and Toxicology . 26:
103-109.
Weis, P., J. S. Weis and J. Couch 1993. Histopathology and bioaccumulation in oysters,
Crassostrea virginica. living on wood preserved with chromated copper arsenate.
Diseases of Aquatic Organisms 17: 41-46.
Weis, P., J. S. Weis and E. Lores. 1993. Uptake of metals from chromated-copper-arsenate
(CCA)-treated lumber by epibiota. Marine Pollution Bulletin 26: 428-430.
Weis, P., J. S. Weis and T. Proctor. 1993. Copper, chromium and arsenic in sediments
adjacent to wood treated with chromated-copper-arsenate. Estuarine and Coastal Shelf
Science 36: 71-79.
Wendt, P. H., R. F. Van Dolah, M. Y. Bobo and T. D. Mathews. 1994. Effects of wood
preservative leachates from docks. Presented at Society of Environmental Toxicology
and Chemistry, 15th annual meeting, Nov. 1994, Denver Colorado.
329
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Table 1. Middle Pond Bulkhead - One Year Old
Distance n j 3 10
% fines 1.9
Sediment Cu 458+96.8
Cr 79+9.2
As 191+14.8
2.0
66+5.6
51+2.8
29+2.8
1.9
53+6.4
46+2.8
16.5+0.7
38.8
41+0.7
43+1.4
16+0.7
1.2
48
48
23
Worms Cu 674±464 27.1+23.8 19.3±2.28 29.1+6.73 18.5±2.87
Cr 5.8±10
-------
Table 1. Middle Pond Bulkhead - One Year Old
Distance
% fines
Sediment Cu
Cr
As
Worms Cu
Cr
As
# species
7.0+2.74
# indiv.
H'
Biomass (g)
0 1
1.9
458+96.8
79+9.2
191 + 14.8
674+464
5.8 + 10
28.6+8.48 2.33 + 1
2.2+0.84
20.6+10.83
0.71+0.67
0.13+0.13
2.0
66+5.6
51+2.8
29+2.8
27.1+23.8
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