GUIDANCE FOR PROTECTING SUBMERGED AQUATIC VEGETATION IN
CHESAPEAKE BAY FROM PHYSICAL DISRUPTION
prepared by
Submerged Aquatic Vegetation Workgroup of the
Living Resources Subcommittee,
Chesapeake Bay Program
Illustration by E. Kasmer from Chesapeake Bay: Introduction to an Ecosystem, 1989
August 1995
EPA 903-R-95-013
CBP/TRS139/95
Printed by the U.S. Environmental Protection Agency for the Chesapeake Bay Program
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Members of Submerged Aquatic Vegetation Workgroup (SAV Workgroup) of the
Chesapeake Bay Program's Living Resources Subcommittee (LRSC)
Chair: Peter Bergstrom, U.S. Fish & Wildlife Service (USFWS)
Workgroup Members
Rich Batiuk, U.S. Environmental Protection Agency (EPA) Chesapeake Bay Program
Office (CBPO)
Steve Bieber, Maryland Department of the Environment (MDE)
Carin Bisland, EPA CBPO
Robert Blama, U.S. Army Corps of Engineers (ACE) Baltimore District
Virginia Carter, U.S. Geological Survey (USGS)
Jim Cummins, Interstate Commission on the Potomac River Basin (ICPRB)
Frank Dawson, Maryland Department of Natural Resources (MDNR)
Kim Donahue, Chesapeake Bay Foundation (CBF)
Steve Funderburk, USFWS
Michele Gomez, ACE Baltimore District
Tim Goodger, National Marine Fisheries Service (NMFS) Oxford Lab
Dick Hammerschlag, National Biological Service (NBS)
Stan Kollar, Harford Community College
Jay Lipscomb, Virginia Marine Resources Commission (VMRC)
Ken Moore, Virginia Institute of Marine Science (VIMS)
Mike Naylor, MDNR
John Nichols, NMFS Oxford Lab
Glenn Page, Alliance for the Chesapeake Bay (ACB)
Bob Orth, VIMS
Nancy Rybicki, USGS
Jim Shell, Metropolitan Washington Council of Governments (MWCOG)
Court Stevenson, University of Maryland Horn Point Environmental Laboratory (HPEL)
Todd Stiles, National Oceanic and Atmospheric Administration (NOAA) Chesapeake Bay
Office
Elizabeth Zucker, CBF
The contributions of two former SAV Workgroup chairs, Linda Hurley Kelsey (USFWS)
and Ed Pendleton (NBS), and former member Cynthia Stenger (MDNR) are also
appreciated.
Guidance for Protecting SAV March 26, 2001
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EXECUTIVE SUMMARY
The underwater vascular plants that make up the submerged aquatic vegetation (SAV)
community in Chesapeake Bay are widely regarded as keystone species and primary
indicators of water quality conditions in the Bay. Although SAV communities currently
have some protection from dredging and construction activities in most areas of the Bay
and its tidal tributaries, the protection of existing SAV beds and potential SAV habitats
from adverse impacts should be evaluated in all cases. State and federal agencies with
resource management responsibilities for shallow water habitats within Chesapeake Bay and
its tidal tributaries should consider the following protective measures in their decision
making processes:
! Protect SAV and potential SAV habitat from physical disruption. Implement a
tiered approach to SAV protection, giving highest priority to protecting Tier I and
Tier II areas, but also protecting Tier III areas from physical disruption. These areas
correspond to areas mapped with SAV in aerial surveys since 1971 (Tier I restoration goal)
and the shallowest waters (to one meter mean low water [MLW], Tier II restoration target),
and to deeper potential SAV habitat (to two meters MLW, Tier III restoration target).
! Avoid dredging in Tier I and Tier II areas, except in a limited manner for
public access, maintenance dredging, and in some circumstances, erosion protection.
! Avoid dredging within Tier III areas. If disruption of these areas is
unavoidable, it should be minimized.
! Avoid dredging, filling, or construction activities that create additional
turbidity sufficient to impact nearby SAV beds during the SAV growing
season. If these activities are unavoidable, any reduction in Secchi depths compared
to pre-disturbance levels should be minimized.
! Establish an appropriate undisturbed buffer around SAV beds to minimize
the direct and indirect impacts on SAV from activities that significantly
increase turbidity. If dredging must occur inside recommended buffers, it should
be done outside the SAV growing season.
! Preserve natural shorelines. Stabilize shorelines, when needed, with marsh
plantings as a first alternative. Use structures that cause the smallest increase in
local wave energy where planting vegetation is not feasible.
! Educate the public about the potential negative effects of recreational and
commercial boating on SAV and how to avoid or reduce them.
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TABLE OF CONTENTS
WORKGROUP ii
EXECUTIVE SUMMARY iii
INTRODUCTION 1
CURRENT SAV PROTECTION IS SUES 4
1. Dredging/development in potential SAV areas 4
2. Mitigation 4
3. Water quality 5
4. Shoreline stabilization 6
5. Competing uses of shallow water areas 6
6. Equal protection for all SAV species 7
RECOMMENDED SAV PROTECTION GUIDANCE 8
REFERENCES 9
GLOSSARY 12
APPENDIX A. CURRENT PROTECTIVE POLICIES AND GUIDELINES A-l
LIST OF TABLES
Table 1. Summary of existing regulations 3
Table 2. Chesapeake Bay SAV water quality habitat requirements 5
Guidance for Protecting SAV August 1995 iv
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INTRODUCTION
This document provides guidance for Chesapeake Bay resource managers and others on
how existing submerged aquatic vegetation (SAV) and tidal shallow water habitats with
potential for supporting SAV in the Bay can be fully protected, given current human uses of
and demands on the Bay. In preparing this guidance document, the Submerged Aquatic
Vegetation (SAV) Workgroup of the Chesapeake Bay Program's Living Resources
Subcommittee reviewed, summarized, and compared current state and federal policies and
guidelines for protection of or minimizing impacts on SAV. Next, the workgroup identified
key management issues facing the protection of existing and future SAV resources. Finally,
building on current state and federal guidelines and policies, the workgroup identified
guidance to first avoid, then minimize, direct impacts to SAV in the Bay and its tidal
tributaries. This guidance document should be used by all local, state, and federal agencies
making decisions that influence the ability of SAV to survive and flourish in Chesapeake
Bay.
The underwater vascular plants that make up the submerged aquatic vegetation community
in Chesapeake Bay are widely regarded as keystone species of the shallow water ecosystem
and primary indicators of water quality conditions in the Bay. The high ecological value of
SAV includes providing food for waterfowl; 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 [13]. SAV also are indicators of
good water quality. Extensive research in Chesapeake Bay showed that SAV tended to
grow best where water clarity was high and nutrient, chlorophyll, and suspended sediment
levels were low [1].
In recognition of the ecological importance of SAV and its role as a bellwether of the
success of broader restoration programs, in 1989, the CBP's Executive Council established
a Submerged Aquatic Vegetation Policy [4] and committed to a policy implementation plan
[5] to achieve as its goal:
a net gain in SAV distribution, abundance, and species diversity in the Chesapeake
Bay and its tidal tributaries.
A basic tenet of this policy is the protection of existing SAV:
from further losses due to increased degradation of water quality, physical damage
to the plants, or disruption to the local sedimentary environment.
This policy reflects the broader goal and objective set forth in the 1987 Chesapeake Bay
Agreement [3], reiterated in 1992 amendments to the Agreement [6]:
Goal: Provide for the restoration and protection of the living resources, their
habitats and ecological relationships.
Guidance for Protecting SAV August 1995
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Objective: Restore, enhance, protect, and manage submerged aquatic vegetation
[3].
The Chesapeake Bay Program developed a three-tiered framework of SAV restoration
goals or targets [1]:
Tier I: restoration or establishment of SAV in areas of historic (1971-present)
distribution
Tier II: restoration or establishment of SAV in potential habitat to a depth of one
meter
Tier III: restoration or establishment in potential habitat to a depth of two meters
These goals imply protection of currently unvegetated habitat. In 1993, the Chesapeake
Executive Council adopted an "interim SAV restoration goal" of 114,000 acres Baywide,
corresponding to the Tier I SAV goal [7].
Through the SAV policy, its signatories—Pennsylvania, Maryland, Virginia, the District of
Columbia, the U.S. Environmental Protection Agency, and the Chesapeake Bay
Commission—committed to:
use existing regulatory and resource management programs, and develop new
programs, to limit permanent and irreversible, direct and indirect impacts to
submerged aquatic vegetation and their habitats. Only in rare circumstances will
losses of submerged aquatic vegetation be considered justifiable [4].
This policy is, by necessity general; in actuality, "permanent and irreversible direct and
indirect impacts" are assessed or determined by regulatory agencies with direct authority on
a case by case basis. Pressure to compromise small, seemingly insignificant SAV beds is
immense, making long term policy commitments difficult to achieve.
This guidance document focuses on impacts of shallow water dredging and construction
activities on SAV and SAV habitats. The guidance is provided to strengthen, and to
achieve greater consistency among, the decision-making processes at the local, state, and
federal levels. The guidance provided here draws on the strengths of existing decision-
making policies and processes for avoiding, or minimizing if avoidance is not possible,
negative impacts on SAV and their shallow water habitats.
This report updates and expands the portions of the Chesapeake Bay Submerged Aquatic
Vegetation Policy Implementation Plan [5] that specifically address SAV protection. The
guidance presented in this report represents the consensus of the Chesapeake Bay Program's
Living Resources Subcommittee and its Submerged Aquatic Vegetation Workgroup.
Guidance for Protecting SAV August 1995
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Categories
Dredging of new
channels
Dredging in SAV beds
Timing restrictions
on dredging
Dredging in areas
that historically
supported SAV
Dredging near SAV
beds /buffer zones
Depositing dredged
material on SAV
Pier Construction
Marina development
near SAV
SAV harvest
Maryland
Not allowed in water
< 3 f t . at MLW
( see Appendix A for
exceptions )
Allowed in areas
where there were
historic channels
Prohibited within
500 yards of SAV
beds, April 15-
October 15
Not recommended
where SAV occurred
during the previous
growing season
See timing
restrictions on
dredging above
Prohibited
Pier out to avoid
dredging of SAV
beds ; minimi ze pier
dimensions
Prohibited in areas
< 4 . 5 ' unless dredged
from upland and
adverse impacts to
SAV are minimi zed
Permit required
Virginia
Limit channels to
minimum dimensions
necessary; avoid
SAV
Usually not allowed
Restrictions may be
placed if in prox-
imity to living
resources
Considered during
the application
review process
Considered during
the application
review process
Locate to minimi ze
impacts
Limit to minimum
necessary for water
access, locate to
avoid SAV
Undesirable near
SAV, or in waters
less than 3' at MLW
US Army Corps of
Engineers (Baltimore
District)2
Not allowed in waters
< 2 f t . MLW in main
channel , < 1.5 f t . MLW
in spurs; presence of
SAV overrides these
parameters
Prohibited upstream of
1.5-2' contour and in
existing beds (see text
for exceptions) ;
channel dimensions may
be res-tricted where
slumping occurs
April 1- June 30 ; April
15-October 15 (species
with two growing
seasons )
Depends on depths and
why SAV disappeared .
Check soils .
3' buffer/11 dredged
be -low existing bottom;
15' buffer from MHW &
for SAV w. dense tuber
mats
Recommend against
Pier out, construct
community piers or
mooring piles to avoid
dredging of SAV beds ;
maintain suitable pier
height above SAV
Avoid historical SAV
beds for new marina
construction; maintain
buffer for marina
expansion
US Environmental
Protection
Agency
Generally, no new
dredging except
in historic
channels
Allowed in
channels or
historic channels
only; not
recommended
otherwise
March 31- June 15
Not recommended
3' buffer/1 '
dredged
Avoidance of SAV
recommended
US Fish and
Wildlife
Service
Avoid shallow water
habitats ; not
re corn-mended in
areas without piers
and historical
deepwater access
Not recommended
March- June
Not recommended
3' buffer/1 '
dredged below
existing bottom
Recommend against
Pier out to avoid
dredging of SAV
beds; construct
community rather
than multiple
individual piers
Avoid
National Marine
Fisheries Service
Not recommended within
existing SAV beds or
adjacent shallows with
potential for bed
expansion
Not recommended
Species-dependent ; April
15-October 15 for most
species; April 1- June 30
for horned pondweed
Not recommended where
SAV has been documented
during the past 2-3
growing seasons
Recommend buffers around
existing beds; no
dredging in areas with
potential bed expansion
Recommend against
Maintain 1:1 ratio of
deck width to deck
height above MLW
Recommend against new
marinas or expansion in
existing beds or
adjacent shallows with
potential for bed
expansion
Limited harvest of
Hydrilla in the Potomac
Guidance for Protecting SAV August 1995
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CURRENT SAV PROTECTION ISSUES
All state and federal agencies that are involved in the management of shallow water habitats
in Chesapeake Bay and its tidal tributaries have their own unique set of SAV protection
regulations and policies. These regulations and policies are summarized in Table 1 and
provided in detail in Appendix A. These existing regulations and policies, although
beneficial for the protection of SAV, must also be considered in all shallow water areas
providing SAV habitats. As such, and in order to achieve the restoration and protection
goals set forth in the Chesapeake Bay Program's policy statements and agreements, the
following six issues must be considered:
1. Dredging/development in potential SAV areas. Current regulations and policies
provide varying levels of protection from dredging of existing SAV beds (Table 1;
Appendix A), but much less or no protection is provided for potential SAV habitat, where
SAV could expand in the future. SAV responds to light, energy, and water quality
conditions during its growing seasons. For this reason, SAV beds may be ephemeral from
year to year. In addition, conditions may return that promote recovery of SAV in
historically vegetated, but currently unvegetated, areas.
Few official policies exist regarding protection of unvegetated areas with documented
historical SAV coverage (Table 1, Appendix A). Maryland's policies protect areas three
feet deep or less at mean low water (MLW), and deeper areas with documentation of SAV
in the previous growing season. The National Marine Fisheries Service (NMFS)
recommends protection of areas having SAV in at least two years during the period from
1985 through the present. Previously vegetated areas may be treated as existing beds by
NMFS even if growth has not occurred for four or five years (or more), if those areas were
historically important to SAV and supported perennial tuber-forming species. Other
agencies consider past occurrence of SAV in the process of approving or recommending
denial of a permit.
2. Mitigation. The National Environmental Policy Act (NEPA, 40 CFR 1508.20) defines
mitigation as five steps: (1) environmental impact avoidance; (2) minimization; (3)
rectification (through repair, rehabilitation, or restoration); (4) reduction or elimination of
impacts; and (5) compensation by replacing or providing substitute resources or
environments. State and federal agencies currently interpret these five steps as a desirable
sequence, and recommend avoidance of impacts altogether as the preferred approach to
mitigation. Restoration and creation of SAV beds are not usually recommended, as the
technology to create or restore SAV beds generally has not proven successful over the long
term, given adverse water quality conditions, inappropriate physical settings and other
factors.1
3. Water quality. Negative impacts of dredging and marine construction on SAV via
reduced water quality are indirectly addressed in many of the regulations and policies
covering shallow water habitats (Table 1; Appendix A). The time of year and buffer
1 The SAV Workgroup is revising a draft report on SAV transplanting in Chesapeake Bay
[14] and will be completing it in the near future.
Guidance for Protecting SAV August 1995 4
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restrictions on dredging are designed to reduce the adverse impacts of increased turbidity
on SAV growing nearby. However, specific levels of water quality needed for SAV growth
were established for Chesapeake Bay, and they should also be included in SAV regulations
and policies. Water quality habitat requirements of SAV for four salinity regimes in the Bay
were established using all available scientific information (Table 2) [1, 10]. Improving
water quality to meet these habitat requirements is the Chesapeake Bay Program's preferred
approach to promoting increases in SAV abundance and distribution to historic levels. A
driving force behind the Chesapeake Bay Program, since its inception in 1983, has been to
reduce loads of nutrients entering the Bay, which should increase water clarity, thus
promoting SAV survival.
Table 2. Chesapeake Bay water quality habitat requirements for SAV restoration to
one meter depth.1
Salinity
Regime2
Tidal Fresh
Oligohaline
Mesohaline
Polyhaline
Light
Attenua-
tion Coef-
ficient
(Kd; m'1)
<2
<2
<„
<„
Secchi
depth
(m)3
>0.7
>0.7
>,.o
>,.o
Total
Sus-
pended
Solids
(mg/1)
<,5
<,5
<,5
<,5
Chloro-
phyll a
( g/1)
<,5
<,5
<,5
<,5
Dissolved
Inorganic
Nitrogen
(mg/1)
-
-
<0.15
<0.15
Dissolved
Inorganic
Phosphorus
(mg/1)
<0.02
<0.02
<0.01
<0.02
Critical
Life
Period
April -
October
April -
October
April -
October
March -
November
Sources: [1, 10]. m = meters, mg/1 = milligrams per liter, g/1 = micrograms per liter. See Glossary for
definitions of the habitat requirements. The SAV habitat requirements are applied as median values
over the April-October critical life period for the tidal fresh, oligohaline and mesohaline salinity
regimes. For the polyhaline salinity regimes, the SAV habitat requirements are applied as median
values from combined March-May and September-November data. Light attenuation coefficient (or
Secchi depth) should be applied as the primary habitat requirement; the remaining habitat requirements
should be applied to help explain regional or site-specific causes of water column and leaf surface light
attenuation, which should be directly managed.
Tidal fresh = salinity <0.5 parts per thousand (ppt); oligohaline = 0.5-5 ppt; mesohaline = >5-18 ppt;
and, polyhaline = > 18 ppt.
3 The Secchi depth habitat requirement is calculated: Secchi depth = 1.45/light attenuation coefficient
(Kd). This represents the minimum median Secchi depth that will permit SAV growth.
Excess nutrients and chronically high turbidity levels play key roles in the decline of SAV.
High nutrient levels reduce water clarity by fueling algae blooms and also harm SAV by
promoting the growth of epiphytes on SAV leaves [1, 10]. Therefore, any upland activities,
such as reforestation or implementation of best management practices, that reduce inputs of
Guidance for Protecting SAV August 1995
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nutrients and sediments to the Bay and its tributaries will help SAV restoration.
Consideration of current and historic SAV occurrence in permitting and mitigation decision
making, as well as during development and implementation of nutrient reduction strategies,
can speed the process of SAV recovery.
High water turbidity, as indicated by April-October median Secchi depth readings less than
0.7-1.0 m (Table 2), is not conducive to SAV survival in the Bay and its tidal tributaries.
Any activities that decrease seasonal median Secchi depths below this level in an area of
current, historical, or potential SAV, should be avoided or minimized if avoidance is
impossible.
4. Shoreline stabilization. Shoreline stabilization practices, especially bulkheading, may
significantly increase local physical energy regimes by preventing dissipation of natural wave
energies. This may result in loss of nearby SAV beds or may prevent recovery of SAV with
improving water quality conditions. The Virginia Marine Resources Commission [24], and
the Maryland Department of Natural Resources [18] both recommend shoreline stabilization
methods that cause the smallest increase in local wave energy. Both agencies recommend
nonstructural methods whenever possible (such as marsh creation), and using stone
revetments or rip-rap where vegetation cannot be used. Both documents discourage
construction of new bulkheads in most locations.
5. Competing uses of shallow water areas. There are several competing uses of shallow
water habitats that may have negative impacts on SAV and SAV habitats. There is not
enough information to recommend protection policies for these competing uses at this time,
but all are important enough to warrant further study. It is hoped that SAV protection
policies for these uses can be addressed in future guidance documents.
Boating. The state and federal agencies listed in Table 1 do not have policies regarding
destruction of SAV by commercial and recreational boating activities. Indeed, when SAV
populations (particularly those of exotic or invasive species) reach levels that inhibit
boating, control programs have been endorsed and funded. Research on boating impacts in
several Chesapeake Bay tributaries documented the relative effects of boat type, boat speed,
water depth, and sediment type on light attenuation in shallow areas [21, 22]. SAV
conservation may warrant boating regulations, but regulations may not find public
acceptance or reasonable means of enforcement. Public education on this issue may be the
most appropriate long-term solution. Signage and informational pamphlets may be
appropriate in known high impact areas. Boat pump-out facilities are also required to
protect water quality, at both existing and new marinas.
Aquaculture. Aquaculture should be avoided in historical and potential SAV habitats to
one meter depth MLW (including all areas in the Tier I restoration goal and the Tier II
restoration target [1]). Issues related to aquaculture and SAV include: shading from
floating racks, impacts from on-bottom racks, and possible nutrient enrichment effects. A
decision on aquaculture permits must weigh the public and private benefits and detriments
between an aquaculture operation and maintenance or recovery of SAV.
Guidance for Protecting SAV August 1995
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Clam dredging. Dredging for soft shell clams can significantly increase local turbidity [11,
16], and it is done near or in SAV beds in some areas, such as the mouth of the Chester
River. Thus, there are negative impacts on SAV. In general, the increases in turbidity
associated with clam dredging are less extensive on sandy substrates and more extensive
and persistent on silt or clay substrates [11, 16].
Crab scraping. Blue crabs are harvested in Chesapeake Bay with a scrape that cuts off a
considerable portion of the leaves of SAV (and flowers or seeds if present), although it does
not usually uproot the plants. Crab scraping is common in Tangier Sound, where it is used
to catch soft crabs and "peelers" (crabs that will shed soon). Crabs tend to seek out the
protection of SAV beds when shedding, so most scraping is done in SAV beds. The long-
term effects of scraping on eelgrass may be more severe if done when flowers and/or seeds
are present [12]. The severity of its effects on SAV also depends on whether new growth
appears at the base of the plant (basal meristem) or at the ends of the stems (apical
meristem). Most crab scraping is currently done in beds of eelgrass, a basal meristem
species. Crab scraping would be more limiting to the growth of apical meristem species
such as widgeongrass, sago pondweed, and most other Chesapeake Bay SAV.
Haul seining. Haul seines are nets used to catch striped bass, carp, and other fish in some
shallow areas of Chesapeake Bay. If seines are drawn through SAV beds, they can cause
physical disruption of SAV. The extent of any damage currently is not known.
6. Equal protection for all SAV species. All species of SAV in Chesapeake Bay provide
similar ecological value and merit equal protection from physical disruption. Introduced
and/or more ephemeral SAV species, sometimes considered less valuable, provide most or
all of the ecological benefits of the native and/or more persistent SAV species. The
presence of any SAV species in an area indicates habitat that is probably suitable for other
SAV species. The SAV restoration goals and targets and water quality habitat
requirements recently developed for Chesapeake Bay SAV apply to all the SAV species
observed and recorded in each salinity zone [1].
Studies found that introduced and/or ephemeral species have equal or higher ecological
value, compared with other SAV, and we do not yet know all the values of many species.
For example, horned pondweed (Zannichelliapalustris), a native pioneer species in tidal
fresh to moderately brackish waters that dies back in early summer, was favored over more
persistent SAV species in Eastern Bay as cover for several species of small, schooling fish
[17]. Similarly, the introduced SAV hydrilla (Hydrilla verticillata\ sometimes considered a
nuisance because it impedes boating and swimming, was found to provide valuable fish
habitat in the Potomac River [15] and in the Upper Bay [20]. Hydrilla changed water
quality in the Potomac River in ways that could benefit living resources [2].
Guidance for Protecting SAV August 1995
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RECOMMENDED SAV PROTECTION GUIDANCE
Protect SAV and potential SAV habitat from physical disruption. Implement a tiered
approach to SAV protection, giving highest priority to protecting Tier I and Tier II
areas but also protecting Tier III areas from physical disruption. These areas
correspond to areas mapped with SAV in aerial surveys since 1971 (Tier I restoration goal,
adopted as a goal by the Chesapeake Executive Council in 1993 [7]) and the shallowest
waters (to one meter MLW, Tier II restoration target). Deeper potential SAV habitat (to
two meters MLW, Tier III restoration target) also should be included[l].
! Avoid dredging in Tier I and Tier II areas, except in a limited manner for
public access, maintenance dredging, and in some circumstances, erosion
protection.
! Avoid dredging within Tier III areas. If disruption of these areas is
unavoidable, it should be minimized. Allowable impacts should be rare [4] and
should be shown to be in the public interest.
Avoid dredging, filling, or construction activities that create additional turbidity
sufficient to impact nearby SAV beds during the SAV growing season. If these
activities are unavoidable, any reduction in Secchi depths, compared with predisturbance
levels, should be minimized. If dredging or other activity that increases turbidity is
permitted during the SAV growing season, Secchi depths should minimally remain or be
managed to be not less than an April-October median Secchi depth of 0.7-1.0 m (see Table
Establish an appropriate undisturbed buffer around SAV beds to minimize the direct
and indirect impacts on SAV from activities that significantly increase turbidity.
Buffer width should be based on the time of year, method of dredging, sediment
composition and local hydrology, method of disposal of dredged material, and size of the
tributary. Undisturbed buffers around SAV beds should be widest during the SAV growing
season, when beds should be a minimum of 500 yards wide for dredging methods and
sediments that are likely to produce major increases in local turbidity. Outside of the SAV
growing season, narrower buffers can be established, but the buffer should be at least three
feet wide for each one foot of sediment removed. If dredging must occur inside
recommended buffers, it should be done outside the SAV growing season.
Preserve natural shorelines. Stabilize shorelines, when needed, with marsh plantings
as a first alternative. Use structures that cause the smallest increase in local wave
energy where planting vegetation is not feasible. The current Best Management
Practices (BMPs) for shoreline stabilization should be followed [18, 24].
Educate the public about the potential negative effects of recreational and
commercial boating on SAV and how to avoid or reduce them. Consider signage and
educational pamphlets in high impact areas.
Guidance for Protecting SAV August 1995 8
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REFERENCES
[1] Batiuk, R., R. Orth, K. Moore, W. Dennison, C. Stevenson, L. Staver, V. Carter, N.
Rybicki, R. Hickman, S. Kollar, S. Bieber, and P. Heasly. 1992. Chesapeake Bay
Submerged Aquatic Vegetation Habitat Requirements and Restoration Targets: A
Technical Synthesis. Chesapeake Bay Program, CBP/TRS 52/92, Annapolis, MD.
[2] Carter, V., N. Rybicki, and R. Hammerschlag. 1991. Effects of submersed
macrophytes on dissolved oxygen, pH, and temperature under different conditions
of wind, tide, and bed structure. Journal of Freshwater Ecology 6:121-133.
[3] Chesapeake Executive Council. 1987. 1987 Chesapeake Bay Agreement.
Chesapeake Bay Program, Annapolis, MD.
[4] Chesapeake Executive Council. 1989. Submerged Aquatic Vegetation Policy for
the Chesapeake Bay and Tidal Tributaries. Chesapeake Bay Program Agreement
Commitment Report. Annapolis, MD.
[5] Chesapeake Executive Council. 1990. Chesapeake Bay Submerged Aquatic
Vegetation Policy Implementation Plan. Chesapeake Bay Program, Annapolis,
MD.
[6] Chesapeake Executive Council. 1992. Amendments to the Chesapeake Bay
Agreement. Chesapeake Bay Program, Annapolis, MD.
[7] Chesapeake Executive Council. 1993. Submerged Aquatic Vegetation Restoration
Goals Directive No. 93-3. Chesapeake Bay Program, Annapolis, MD.
[8] Delaware Department of Natural Resources and Environmental Control (DNREC).
1992. Regulations Concerning the Use of Subaqueous Lands. DE DNREC,
Division of Water Resources.
[9] Delaware Department of Natural Resources and Environmental Control (DNREC).
1993. State of Delaware Marina Regulations. DE DNREC, Division of Water
Resources.
[10] Dennison, W. C., R. J. Orth, K. A. Moore, J. C. Stevenson, V. Carter, S. Kollar, P.
W. Bergstrom, and R. Batiuk. 1993. Assessing water quality with submersed
aquatic vegetation: Habitat requirements as barometers of Chesapeake Bay health.
BioScience 43: 86-94.
[11] Drobeck, K. G., and M. L. Johnston. 1982. Environmental Impact of Hydraulic
Escalator Dredging on Oyster Communities. UMCEES Report 82-5 CBL,
University of Maryland, Chesapeake Biological Laboratory, Solomons, MD. 51 pp.
Guidance for Protecting SAV August 1995
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[12] Fonseca, M. S., G. W. Thayer, and A. L. Cheater. 1984. Impact of scallop
harvesting on eelgrass (Zostera marina) meadows: implications for management.
North American Journal of Fisheries Management 4: 286-293.
[13] Hurley, L. 1991. Submerged Aquatic Vegetation. Pages 2-1 to 2-19 in S.
Funderburk, S. Jordan, J. Mihursky, and D. Riley, eds. Habitat Requirements for
Chesapeake Bay Living Resources, Second Edition. Chesapeake Bay Program,
Annapolis, MD.
[14] Hurley-Kelsey, L., and K. Reshetiloff In preparation. A Review of Transplanting
and Its Feasibility for Restoring Chesapeake Bay Submerged Aquatic Vegetation.
U.S. Fish & Wildlife Service, Annapolis, MD.
[15] Killgore, K., R. Morgan, and N. Rybicki. 1989. Distribution and abundance of
fishes associated with submersed aquatic plants in the Potomac River. North
American Journal of Fish Management 9:101-111.
[16] Kyte, M. A., and K. K. Chew. 1975. A Review of the Hydraulic Elevator Shellfish
Harvester and Its Known Effects in Relation to the Soft-shell Clam, Mya arenaria.
Report #WSG 75-2, University of Washington, Division of Marine Sciences.
[17] Maldeis, R.W. 1978. Relationship Between Fishes and Submerged Aquatic
Vegetation in the Chesapeake Bay. Report to EPA Chesapeake Bay Program,
Philadelphia, PA, Order No. WD-8-0541-J-1. 29 pp.
[18] Maryland Department of Natural Resources. 1994. Shore Erosion Control
Guidelines for Waterfront Property Owners. Maryland Department of Natural
Resources, Water Resources Administration, Annapolis, MD. 40 pp.
[19] Orth, R. J., J. F. Nowak, G. F. Anderson, and J. R. Whiting. 1994. Distribution of
Submerged Aquatic Vegetation in the Chesapeake Bay and Tributaries and
Chincoteague Bay — 1993. Virginia Institute of Marine Science, Gloucester Point,
VA. (plus similar annual reports for 1978, 1984-87, and 1989-92)
[20] Serafy, J., R. Harrell, and C. Stevenson. 1988. Quantitative sampling of small
fishes in dense vegetation: Design and field testing of portable "pop-nets." Journal
of Applied Ichthyology 4:149-157.
[21] Stevenson, C. 1994. Recreational Boating and Submersed Aquatic Vegetation in
the South River & Elk River. Final report (CEES #07-4-30368) to the Boating
Administration, Maryland Department of Natural Resources, Annapolis, MD.
[22] Stevenson, C., K. Sundberg, and L. Russ. 1995. Recreational Boating and
Submersed Aquatic Vegetation: Choptank and South Rivers. Final report (CEES
Guidance for Protecting SAV August 1995 10
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#07-4-30409) to the Boating Administration, Maryland Department of Natural
Resources, Annapolis, MD.
[23] Virginia Marine Resources Commission. 1986. Subaqueous Guidelines:
Guidelines for the Permitting of Activities Which Encroach In, On, or Over the
Submerged Lands of the Commonwealth of Virginia. Virginia Marine Resources
Commission, Newport News, VA.
[24] Virginia Marine Resources Commission. 1994. Shoreline Development BMP's.
Virginia Marine Resources Commission, Newport News, VA.
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GLOSSARY
aquaculture - The propagation and rearing of aquatic species in controlled or selected
environments (National Aquaculture Act, P.L. 96-362).
Best Management Practices (BMPs) - Management practices that help insure project
integrity for the design life of the project, while minimizing the potential adverse impacts
associated with construction and maintenance [18, 24].
bulkhead - A vertical structure or partition, usually running parallel to the shoreline, for the
purpose of retaining upland soils, while protecting them from wave action [24]. Usually
constructed of pressure-treated lumber or concrete.
Chesapeake Bay Commission - A group of state legislators and governors' appointees
from the three states in the Chesapeake Bay Program (Maryland, Virginia, and
Pennsylvania) that discusses, coordinates, and drafts environmental legislation that affects
the Chesapeake Bay and its watershed.
Chesapeake Bay Program - The Chesapeake Bay Program is the cooperative partnership
among the states of Maryland, Pennsylvania, Virginia; the District of Columbia; the Chesapeake
Bay Commission, atri-state legislative body; the U.S. Environmental Protection Agency,
representing the federal government; and participating citizen advisory groups. The Chesapeake
Bay Program was established in 1983 under the Chesapeake Bay Agreement.
Chesapeake Executive Council - The top policy making body of the Chesapeake Bay
Program. Made up of the governors of Maryland, Virginia and Pennsylvania, the mayor of
the District of Columbia, the Administrator of the U.S. Environmental Protection Agency,
and the chair of the Chesapeake Bay Commission. They meet annually to approve new
initiatives, review the progress, and set long term priorities and goals of the Chesapeake
Bay Program.
chlorophyll a - A measure of the photosynthetic pigment in a water sample, mainly from
the phytoplankton (algae) suspended in it. More chlorophyll indicates more phytoplankton.
Phytoplankton reduce water clarity. One of the SAV habitat requirements (see Table 2) [1,
10].
clam dredging - A commercial fishing technique used in Maryland to harvest soft shell
clams. A hydraulic dredge mounted on the side of a boat uses jets of water to stir up about
one foot of sediment. Any the clams in the sediment are transported up a conveyor belt to
the boat.
competing uses - Uses of the same habitat or resource that are incompatible to some
extent.
Guidance for Protecting SAV August 1995 12
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crab scrape - A metal frame with a light mesh bag attached that is dragged along the
bottom to collect soft crabs and peelers (crabs that will shed soon). It is usually used in
SAV beds because crabs often shed there.
Dissolved Inorganic Nitrogen (DIN) - A measure of the nitrogen in water available for
plant growth. Calculated from the sum of filtered nitrite (NO2), nitrate (NO3), and ammonia
(NH4). One of the SAV habitat requirements (see Table 2) [1, 10].
Dissolved Inorganic Phosphorus (DIP) - A measure of the phosphorus in water available
for plant growth. Equivalent to filtered orthophosphate (PO4). One of the SAV habitat
requirements (see Table 2) [1, 10].
dredge material - Bottom sediments removed during dredging.
dredging - Removal of bottom sediments, usually to deepen the water to permit navigation.
Dredging can also refer to certain commercial fishing techniques, for example, clam
dredging, oyster dredging, and crab dredging.
epiphytes - A plant growing on another plant; in this document, they refer to algae growing
on SAV leaves or stems. They can reduce light available to the SAV, harming the SAV.
ground truthing - Surveys done on the ground to check information from aerial
photography. This is done as part of the baywide SAV aerial survey program to verify
SAV bed locations and to identify the species they contain.
habitat requirements - Environmental conditions that are necessary to support the survival
and growth of plants or animals [13]. See "SAV habitat requirements."
haul seining - Using a seine to catch fish in shallow water. The seine is a long net with
floats on top and weights on the bottom that is pulled through the water, and may be hauled
up on shore to remove the fish from it.
historical SAV habitat - An area of shallow water in Chesapeake Bay and its tidal
tributaries where SAV has been recorded by aerial surveys since 1971. The overlay of these
areas is the Tier I restoration goal [1, 7].
light attenuation coefficient (Kd) - The rate at which sunlight is reduced in intensity per
meter in the water column. It is usually measured for the light wavelengths used by plants
in photosynthesis, called Photosynthetically Active Radiation (PAR). It can be converted to
a Secchi depth using the equation: Secchi depth = 1.45/Kd [1]. One of the SAV habitat
requirements (see Table 2) [1,10].
Mean High Water (MHW) - The average height of high tidal waters over a 19-year
period [24].
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Mean Low Water (MLW) - The average height of low tidal waters over a 19-year period
[24].
maintenance dredging - Dredging to maintain existing navigation channels with
documented historic boat use. In some circumstances, this may include areas not previously
dredged.
mitigation - Environmental impact avoidance, minimization, rectification (through repair,
rehabilitation, or restoration), reduction or elimination, and compensation by replacing or
providing substitute resources (NEPA, 40 CFR 1508.20).
revetment - A facing of stone, concrete, etc., built to protect a scarp, eroding bank, or
shore structure against erosion by waves or currents [18].
rip-rap - Stone used for shoreline stabilization. The stone should be hard and angular and
of such a quality that it will not disintegrate on weathering, with individual stones no longer
than three times their minimum dimension [24]. Filter cloth is placed beneath the stones to
retain soils.
SAV (Submerged Aquatic Vegetation) - Vascular plants that, except for some flowering
structures, live and grow below the water surface [4]. The term, as used in Chesapeake
Bay, sometimes includes muskgrass (Characeae), a family of quasi-rooted algae that
resemble vascular SAV, but no other algae [19]. "Submersed" may be used instead of
submerged [10].
SAV bed - An area on the bottom of a water body colonized by one or more species of
SAV, in varying density [19].
SAV growing season - April 1 - October 31 in areas of Chesapeake Bay where surface
salinity is usually below 18 parts per thousand (ppt). In areas with higher salinity
(polyhaline, over 18 ppt), found only in Virginia, the growing season is March 1 - May 31
and September 1 - November 30 [1].
SAV habitat requirements - Minimum water quality levels that SAV need to grow, as
determined by research in several areas of Chesapeake Bay [1, 10, 13]. The requirements
are based on the average (median) surface values over the SAV growing season. Habitat
requirements include five parameters (Table 2). Light attenuation coefficient (Kd) is a
measure of how rapidly the ambient light is reduced for each meter below the surface, in
meters"1, and can be approximated by a calculation using Secchi depth (Table 2). Total
suspended solids (TSS) is a measure of the dried weight of solids retained by a 0.7 micron
filter, in milligrams per liter. Chlorophyll a (CHLA) is a measure of the chlorophyll content
of the algae retained on a 0.7 micron filter, in micrograms per liter. Dissolved inorganic
nitrogen (DIN) is a measure of the dissolved nitrate, nitrite, and ammonia concentration in
the water, in milligrams per liter. Dissolved inorganic phosphorus (DIP) is a measure of the
dissolved orthophosphate concentration in the water, in milligrams per liter.
Guidance for Protecting SAV August 1995 14
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SAV tiers - Tier I restoration goal: Areas of Chesapeake Bay and its tidal tributaries with
SAV mapped in aerial surveys since 1971, totaling 114,000 acres [1, 7]. Tier II restoration
target: Potential SAV habitat in Chesapeake Bay and its tidal tributaries to one meter depth
MLW [1]. Tier III restoration target: Potential SAV habitat in Chesapeake Bay and its
tidal tributaries to two meter water depth MLW [1].
Secchi depth - A measure of water clarity; the depth at which a white and black or all white
disk just disappears from view as it is lowered in the water column. Habitat requirements
for light attenuation coefficient (Kd) have been established for SAV, which can be
converted to Secchi depth (see Table 2) [1, 10].
shallow water - Waters that are one meter (approx. three feet) deep or less at mean low
water. Can include waters up to two meters (approx. six feet) deep at MLW, which are
potential SAV habitat in Chesapeake Bay (see SAV Tier III definition).
total suspended solids - A measure of the amount of organic and inorganic solids
suspended in the water column, in milligrams per liter. One of the SAV habitat
requirements (see Table 2) [1, 10].
turbidity - A measure of suspended solids or dissolved materials in the water column that
reduce water clarity, thus reducing light available to SAV. Usually measured in tidal areas
by its effects on water clarity, as Secchi depth or light attenuation coefficient.
Guidance for Protecting SAV August 1995 15
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Appendix A
CURRENT PROTECTIVE POLICIES AND GUIDELINES
Current guidance to avoid or minimize impacts to SAV in Chesapeake Bay and its tidal
tributaries exist as both regulatory guidelines and unwritten policy. State and federal
agency programs and legislative mandates are discussed below and are summarized for
general comparison below and in Table 1. Pennsylvania is not included because it does not
contain any tidal tributaries of Chesapeake Bay. Local agencies may also have input on
activities that affect SAV, but a review of their policies is beyond the scope of this
document.
STATES AND THE DISTRICT OF COLUMBIA
Maryland
The Maryland Department of Natural Resources, Water Resources Administration, Tidal
Wetlands Division, regulates dredging and filling activities as well as construction activities
(piers, shoreline protection, etc.) in tidal and tidally influenced wetlands and shallow water
areas. Maryland's Tidal Wetlands Regulations (adopted 2-14-94) provide both direct and
indirect protection to SAV. Permit or license applications are required to "first avoid and
then minimize the loss of tidal wetlands." Permits and licenses are evaluated by the
Department of Natural Resources in part by the degree that the permitted action would
affect "shallow water areas suitable to support submerged aquatic vegetation."
Applications for dredging permits must include a dated map that delineates where SAV
beds currently occur and details of how the SAV was sampled to determine its distribution.
Dredging is not generally allowed in less than three feet of water unless: (1) historic boat
use since 1972 can be documented by photographs or historic depths can be documented on
navigation charts or bathymetric surveys; (2) "the proposed channel represents the smallest
dimension necessary to connect a basin created from upland, or is a public boat ramp to
navigable waters"; (3) "the proposed channel is necessary for construction of shore erosion
control projects"; or (4) "otherwise determined by the Department."
In currently unvegetated areas, dredging is generally not allowed if SAV was present during
the previous year. Dredged channel alignments are required to "first avoid and then
minimize impacts to shellfish beds, submerged aquatic vegetation, and vegetated tidal
wetlands" and "shall be located the maximum distance feasible" from these sensitive areas.
Deposition of dredged materials on SAV beds is prohibited. Dredging is not allowed
within 500 yards of SAV beds from April 15 through October 15.
Maryland guidelines also cover SAV protection regarding new development. New marinas,
or expansion of existing marinas, is prohibited in areas where natural depths are less than
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4.5 feet "unless the marina basin is excavated from upland" and adverse impacts to SAV
and other resources are minimized.
Maryland law indirectly protects some areas of SAV habitat from disturbance by hydraulic
clam dredging by prohibiting clam dredging within a certain distance from shore. This
distance varies by county (NRA 4-1038, Annotated Code of Maryland). There are no water
depth restrictions.
Protection of SAV is further implicitly mandated through several programs. The Maryland
Critical Areas Law (NRA 8-1801 et seq., Annotated Code of Maryland) provides strict
guidelines for any new development in "land and water areas within 1,000 feet beyond the
landward boundaries of state or private wetlands and the head of tide" and in the waters and
wetlands of the Chesapeake Bay below the head of tide. The Department of Natural
Resources Power Plant Research and Environmental Review Division is responsible for
reviewing all federal activities to assure their consistency with the provisions of the
Maryland Coastal Zone Management Plan (authorized through the Coastal Zone
Management Act, 16 U.S.C. 1451-1464), including the protection of SAV.
Maryland also protects SAV and SAV habitat through regulation of water quality. A state
Water Quality Certification Program (COMAR 26.08.02) under Section 401 of the Clean
Water Act (133 U.S.C. 1341-1987) is administered by the Department of the Environment
to assure that discharges of pollutants into state waters meet established state water quality
standards. The Department of the Environment also issues National Pollutant Discharge
Elimination Program (NPDES; 40 CFR 122.26) permits for discharge of pollutants from a
point source into navigable waters.
Virginia
The Virginia Marine Resources Commission (VMRC), under Chapter 12 of Title 28.2 of
the Code of Virginia, regulates any encroachments in, on, over, or under state-owned
subaqueous bottoms. VMRC's Subaqueous Guidelines [23] are designed, among other
things, to minimize impacts on aquatic habitats. The guidelines state that: "dredging in
shellfish areas, both public and private, beds of submerged aquatic vegetation and other
highly productive areas is discouraged"; authorized overboard disposal of dredged material
must be located so as to minimize impacts on SAV; locations of jetties, groins, and
breakwaters must not "unduly disturb marine resources [including SAV]"; and "alteration of
submerged aquatic vegetation...should be minimized wherever possible in the planning and
location of submerged structures."
Separate guidelines and criteria for marina, boat mooring facilities, and placement of sandy
dredged materials on beaches are also provided by VMRC. Marinas or community facilities
for boat mooring "should not be sited close to areas of very high natural resource value
such as...seagrass communities." The dredging of access channels should be limited to
"minimum dimensions for navigation and should avoid sensitive areas such as... seagrass
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beds." These guidelines also state that "piers and wharves crossing vegetated wetlands and
seagrass areas should be limited to the minimum necessary for water access." Projects to
place dredged sand on coastal beaches must be engineered to minimize environmental
impacts to natural resources, including SAV.
In evaluating coastal permits, an environmental assessment is provided to VMRC by the
Virginia Institute of Marine Science of the College of William and Mary (VIMS) to address
impacts and recommend ways that those impacts can be minimized. VIMS' review takes
into consideration impacts to SAV.
Protection of SAV through water quality regulation is accomplished by the Virginia
Department of Environmental Quality (VDEQ), Office of Water Resources Management.
VDEQ administers Virginia's Water Protection Permit Program (VR 680-15-02) and the
VPDES permit program (VR 680-14-01) and adopts water quality standards and
requirements. Section 404 permits are reviewed by VDEQ as well.
Local Wetlands Boards in Virginia also provide some protection to SAV from indirect
impacts such as upland erosion. These boards review projects in tidal wetlands for
environmental impacts and their minimization in a public interest review.
Virginia's Chesapeake Bay Preservation Act (Chapter 21, Section 10.1 2100-2115, Code of
Virginia) parallels Maryland's Critical Areas Law to indirectly protect SAV through the
lessening of developmental impacts to shoreline areas and coastal wetlands. Protection or
restrictive measures directly regarding SAV are not specifically outlined in the Act. Water
quality impact assessments required of local assistance boards may address other sensitive
environmental areas, including SAV beds, at their discretion.
Delaware
Delaware has regulations concerning disruption of SAV by dredging or marina
construction, published by the Delaware Department of Natural Resources and
Environmental Control (DNREC) [8, 9]. The regulations state that prohibited dredging
projects include:
Dredging of biologically productive areas, such as ... submerged aquatic
vegetation, if such dredging will have a significant or lasting impact on the biological
productivity of the area [8, pg. 15].
There are no time of year or SAV buffer restrictions, and a definition of "significant or
lasting impact" is not provided. Dredging in SAV beds has not been an issue recently,
because there are very few or no SAV currently growing in Delaware's tidal waters. Recent
eelgrass plantings in coastal bays by DNREC became established but were destroyed by
conflicting recreational uses.
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"General siting considerations" for Delaware boat docking facilities include:
Structures should be constructed to avoid dredging or filling, with minimal impact
on aquatic vegetation and wetlands, and without dead-end or poorly flushed
lagoons.
Docks and piers should extend out from the shoreline far enough so as to eliminate
need for dredging and filling, and provide sufficient height to allow light to penetrate
to vegetation underneath and alongside [8, pg. 17].
Specific Delaware regulations on marinas and SAV provide that:
Applicants [for marina permits] must demonstrate that short- and long-term impacts
to SAV have been avoided, and unavoidable impacts have been minimized and can
be compensated for [9, pg. 21].
Compensation shall be required in a ratio of 2:1 for SAV beds disturbed, unless the
applicant can demonstrate. . .that a smaller area can provide the same ecological
productivity and function [9, pg. 25].
The compensated areas must "employ the same species (flora and fauna) as the ones
disturbed" and must achieve the same "average density and average shoot height" as the bed
that was disturbed [9, pg. 25]. Replanting is required if the compensation SAV beds fail,
paid for with a ten-year bond for twice the estimated replanting cost, released after five
years if the compensation is successful [9, pg. 26].
Nonstructural shoreline erosion control measures are "preferred" in situations where they
are feasible, and the structural measures recommended where needed are revetments and
gabions [8, pg. 18].
District of Columbia
Other than general, unwritten guidance, no policies exist in the District of Columbia
regarding avoidance or minimization of impacts to SAV during dredging, marina
construction or expansion, or other activities.
The District's involvement with SAV has largely been based on control of hydrilla, Hydrilla
verticillata. With the invasion of hydrilla in the upper tidal Potomac River in the 1980's, the
District of Columbia entered into a multiagency program to harvest this exotic species
annually as a means of control. The Potomac Aquatic Plant Control Program currently
includes the Metropolitan Washington Council of Governments, the Commonwealth of
Virginia, the State of Maryland, and the Army Corps of Engineers as partners. Protection
to native plant species is provided by prohibiting other control or eradication measures,
such as herbicide application, and by strictly limiting the amount and locations of
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mechanical harvesting. Specific regulations concerning SAV harvest were published on
April 15, 1994, on pages 1971-1977 of the District of Columbia Register.
FEDERAL AGENCIES
Submerged aquatic vegetation is afforded increased protection under Section 404 of the
Clean Water Act (33 U.S.C. 1341-1987) and Section 10 of the Rivers and Harbors Act (33
U.S.C. 403), which regulate the discharge of dredged or fill material into the nation's
waters. Authority for administering the Clean Water Act rests with the U.S. Environmental
Protection Agency; a federal permit program is delegated to and administered by the U.S.
Army Corps of Engineers. Potential impacts on Special Aquatic Sites, such as submerged
aquatic vegetation, are considered in the permit review process. The Rivers and Harbors
Act is administered by the Corps; Section 10 of the Act regulates, through a permit
program, all activities in navigable waters including dredging and placement of structures.
Permit applications under the Clean Water and Rivers and Harbors Acts are routinely
reviewed by the U.S. Army Corps of Engineers and by the U.S. Environmental Protection
Agency (EPA), the U.S. Fish and Wildlife Service (USFWS), and the National Oceanic and
Atmospheric Administration's (NOAA) National Marine Fisheries Service (NMFS).
Comments from the latter agencies are provided to the Corps of Engineers to recommend
approval (often with recommended conditions or project modification) or denial of
individual permits. Consultations among agencies on environmental impacts of federal and
other projects are also required through the provisions of the Fish and Wildlife Coordination
Act (16 U.S.C. 661-667e) and the National Environmental Policy Act (42 U.S.C. 4231-
4370a).
In the permit review and approval processes, special consideration is made for the
protection and preservation of SAV. Other than the legislative mandates given above, the
federal agencies have no written policies specific to SAV protection. Guidelines that the
regulatory agency (Corps) and the commenting agencies (EPA, USFWS, and NMFS) use to
make their decisions and recommendations are summarized below and in Table 1.
Guidelines in most cases are specific to physical alterations accompanying dredging and
direct impacts.
U.S. Army Corps of Engineers
Guidelines and general policies of the Corps of Engineers Baltimore District include the
following:
1. No dredging is permitted in SAV beds, unless the dredging is:
a. within an existing entrance channel;
b. within historic channels;
c. within an existing slip at a marina; or
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d. in a sparsely vegetated area where no more
than one foot of dredged material is to be removed.
2. A 15-foot buffer area is required for species that have dense tuber mats.
3. For every foot of depth to be dredged below the existing bottom, there must
be three feet of buffer around the SAV.
4. In areas that have SAV in or adjacent to the dredge area, channels may be
restricted in their width or depth to prevent slumping of the substrate and
potential loss of SAV.
5. A time of year restriction, usually recommended by a commenting resource
agency (e.g., USFWS orNMFS), is imposed on dredging adjacent to SAV
beds. This restriction usually protects SAV during the period of optimal
growth and reproduction (April 1-June 30). If the species has two growing
seasons, the usual time restriction is April 15 through October 15.
6. Where possible, construct a pier out to the channel to avoid dredging of
SAV, as long as general navigation is not impeded.
7. To preserve potential SAV habitat, dredging of main channels generally
should end at the 2 foot MLW contour; spur channels should generally end
at the 1.5 foot MLW contour.
8. Dredging must be at least 15 feet from MHW.
Guidelines and general policies may be different in other Corps districts.
U.S. Environmental Protection Agency
Guidelines EPA uses in their review process include:
1. Time of year restrictions on dredging of March 31 through June 15.
2. Avoidance and/or minimization of dredging in existing SAV beds wherever
"practicable." No dredging through SAV beds.
3. Generally, no new dredging in shallow water areas that were not dredged in
the past. This restriction is project-specific and may be modified depending
on resources and issues involved.
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4. Buffers established landward of a contiguous contour line at a specific depth
(Mean Low Water, MLW) and/or at a distance of 15 ft at Mean High Water
(MHW; recommended buffer varies on a case-by-case basis).
5. Recommended avoidance of SAV beds for dredging and/or boat slips in
marina project proposals.
U.S. Fish and Wildlife Service
Guidelines USFWS uses in their review process include:
1. Minimum 3:1 no-dredge buffer around existing SAV beds. That is, allow a
three-foot lateral buffer for every one foot of vertical dredged material
removal in the dredged channel.
2. No new dredging in areas around piers unless there was historical deepwater
access.
3. Construct piers out to the channel to avoid shallow water habitat; construct
community piers instead of several single piers.
4. Minimize width and depths of dredged channels and spur channels.
5. Dredging restricted March to June.
6. Stake SAV beds prior to dredging.
7. Require a post-dredging survey to ensure channels were dredged to depths
allowed in the permit.
8. No dredging within 15-20 feet of MHW shoreline, bulkheads, or tidal marsh,
except in existing marinas.
9. Upland dredged material disposal sites preferred.
NOAA National Marine Fisheries Service
Guidelines NMFS uses in their review process include:
1. Protect, where practical, existing beds of SAV against impacts associated
with dredging, fill, pile-supported platforms, marina development, and other
activities. Existing beds are defined as those that currently support SAV, or
supported SAV during the past two to three growing seasons. Previously
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vegetated areas may be treated as existing beds even if growth has not
occurred for four or five years (or more), if those areas were historically
important to SAV and supported perennial tuber-forming species.
2. Where practical, protect areas that may support expansion of SAV from
development activities (especially dredging) in areas adjacent to existing
SAV beds of similar depth and physical/sedimentary quality . Depth
contours should be determined by observing depths over which the majority
(or greatest density) of SAV is occurring.
3. Provide additional protection to perennial species and/or those species with
extensive root or rhizome systems, native non-nuisance species, and species
with high ecological values (for example, eelgrass, widgeon grass, wild
celery, and redhead grass).
4. Recommend ground-truthing surveys by competent consultants or agency
staff for large projects to delineate beds. Where species with variable
season-to-season distribution (such as horned pondweed) are known to
predominate, surveys within a year of the permit review period are preferred.
5. In general, maintain a no-dredge shoreline buffer within all predominantly
shallow, but nonvegetated, areas where dredging is proposed to permit SAV
establishment or vegetative expansion of existing beds; generally, 15 feet
from the dredge cut to the MHW shoreline or the MLW line is
recommended.
6. Minimize dredging in nonvegetated shallows capable of supporting SAV
through extension/construction of open pile piers and limit dredging to only
that necessary for access and mooring.
7. Restrict dredging in the vicinity of SAV from April 15 to October 15. When
horned pondweed is the only species present, restrict dredging from April 1
through June 30.
8. Minimize impacts to SAV during maintenance dredging of existing channels
or marinas.
9. Construct shoreline stabilization and beach nourishment structures landward
of SAV beds.
10. Deny the following proposed activities, if within SAV beds or immediately
adjacent areas with potential for bed expansion: new marinas, marina
expansions, aquaculture, artificial reefs, open-water dredge disposal, pile-
supported platforms, ramps and marine railways.
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11. Construct open-pile piers over nonvegetated areas (if practical) or maintain a
1:1 ratio of deck width to deck height (above MLW).
12. Avoid laying pipelines and cables in vegetated areas, if practical, or return
post-construction bottom within existing SAV beds to preexisting elevations
and sediment types.
13. Harvesting is not recommended, except in the Potomac River for hydrilla.
OTHER CONSIDERATIONS
Dredging and other development in the shallows and nearshore areas of the Chesapeake
Bay and its tributaries is considered by state and federal agencies on a case-by-case basis.
Permit decisions and recommended modifications are influenced by a number of additional
factors including:
! Past precedents for or against development of an area (i.e., past development
history, including permits approved or denied).
! Future precedents that may be set for or against development by the permit
in question.
! The amount of existing development (numbers of marinas, boat use, numbers
of existing piers, extent of current bulkheading, etc.).
! Potential for recovery of an area for SAV, considering present development
and habitat and water quality conditions.
! Historical boating access.
! Special biological issues, such as endangered species, special or important
biological functions or values, or contaminants.
! The interests of the public, i.e., socioeconomic considerations.
A-9
A-9
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