United States Environmental Protection Agency
CBP/TRS 11/87
August 1987
1H
541.5
.E8
078
903R87007
Distribution of
Submerged Aquatic Vegetation
in the Chesapeake Bay and
Tributaries-1984
Chesapeake
Bay
Program
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Distribution of Submerged Aquatic Vegetation in
the Chesapeake Bay and Tributaries - 1984
by
Robert Orth1, Jim Simons2
Ruth Allaire3, Virginia Carter", Larry Hindman5
Kenneth Moore1, and Nancy Rybicki"
1. Virginia Institute of Marine Science
School of Marine Science
College of William and Mary
Gloucester Point, VA 23062
2. The Bionetics Corporation
U.S. EPA-EPIC
Vint Hill Farms Station
Warrenton, VA 22186
3. Dept. of Environmental and Natural Sciences
Northern Virginia Community College
Woodbridge, VA 22191
4. U.S. Geological Survey
Reston, VA 22092
5. Dept. of Natural Resou^ets
Tawes Office Building
Annapolis, MD 21 401
Funded by: NOAA Grant No. NA-83-AA-D-C2048
EPA Cooperative Agreement X-003301-01
MD Department of Natural Resources
Virginia Institute of Marine Science
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CONTENTS
Page
Tables iii
Figures iv
1 . Introduction 1
2. SAV Species 4
3. Methods 5
Aerial photography 5
Mapping process 8
Ground truth and other data bases 18
4. Results and Discussion 23
Susquehanna Flats 39
Upper Eastern Shore 42
Upper Western Shore 43
Chester River 43
Central Western Shore 44
Eastern Bay 44
Choptank R iver 45
Patuxent River 46
Middle Western Shore 46
Lower Potomac River 46
Upper Potomac River 56
Middle Eastern Shore 62
Tangier Island Complex 65
Lower Eastern Shore 66
Reedville 67
Rappahannock River Complex 6?
New Point Comfort Region 71
Mobjack Bay Complex 71
York River 72
Lower Western Shore 72
James River 73
5. Conclusions 74
6. Literature Cited 79
7. Appendices
A. Species of submerged aquatic plants found in the
Chesapeake Bay and tributaries 82
B. Topographic quadrangles showing the distribution
of SAV 83
iii
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TABLES
Number Page
1 Guidelines for acquisition of aerial photographs 7
2 List of topographic quadrangles in Chesapeake Bay SAV
study area 10
3 Area description for 21 major sections in the Chesapeake
Bay SAV study area 16
4 Total area of SAV by quadrangles for 1978 and 1984 .... 24
5 Number of hectares of SAV for each of the major sections
in the bay for 1978 and 1984 28
6 Number of square meters of SAV in each quadrangle of the
21 major sections 29
7 Number of square meters of SAV in each of the density
classes for quadrangles having SAV , 36
8 Frequency of stations with SAV in upper Chesapeake Bay,
1971-1984 40
9 Species of SAV found on vegetated transects in the tidal
Potomac River and transition zone, 1984, by USGS .... 48
10 Relative occurrence of vegetation in the tidal Potomac
River and estuary, 1978-81 and 1984 50
11 Grid locations in the transition zone of the Potomac
River where SAV was found in 1984 by the NVCC survey . . 51
12 Total suspended solids output from primary outlet of
Blue Plains Treatment Plant, 1982 and 1983 63
13 Secchi depth in upper and lower tidal river, 1978-81 and
1983 64
14 Areas of SAV at historical sites in the lower bay zone,
1937-1984 68
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FIGURES
Flight lines used to acquire photographs of SAV in
Maryland and Virginia .................. 6
2 Location of topographic quadrangles in the Chesapeake
Bay ........................... 9
3 Crown density scale for estimating SAV bed density .... 13
4 Location of 3 zones and 21 major sections in the Chesapeake
Bay for delineation of SAV ............... 15
5 Location of quadrangles along transition of Potomac River
for SAV study conducted by NVCC ............. 20
6 Location of vegetation sampling transects in the tidal
and transition portion of the Potomac River conducted
by USGS in 1983 and 1984 ................ 21
7 Percent of stations with SAV at selected sites in the
upper bay, 1971-1984 .................. 41
8 Distribution of wild celery in the transition zone,
Potomac River ...................... 52
9 Distribution of Hydrilla, coontail and milfoil in the
transition zone, Potomac River ............. 53
10 Distribution of sago pondweed, curly pondweed and redhead
grass in the transition zone, Potomac River ....... 54
11 Distribution of widgeongrass , horned pondweed, Char a sp.
and common elodea in the transition zone, Potomac River. 55
12 SAV species diversity in the tidal Potomac River, 1983 . . 57
13 SAV species diversity in the tidal Potomac River, 1984 . . 58
14 Distribution of Hydrilla in the tidal Potomac River in
1983 .......................... 60
15 Distribution of Hydrilla in the tidal Potomac River in
1984 .......................... 61
16 Trends in SAV coverage at historical sites in lower Bay
zone, 1937-1984 ..................... 70
17 Trends in SAV occurrence in the upper Chesapeake Bay ... 77
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SECTION 1
INTRODUCTION
Communities of submerged aquatic vegetation (SAV) are an integral part
of the Chesapeake Bay ecosystem. They provide an important habitat for many
species which use SAV either as a food source or as protection from
predators, e.g. a nursery. They reduce currents and baffle waves, allowing
for deposition of suspended material. In addition, they bind sediments with
their roots and rhizomes to prevent erosion of the underlying material.
They are important in nutrient cycling both through the absorption and
release of nitrogen and phosphorus (Thayer, et. al, 1975; Kemp, et. al.,
1984; Orth, et. al., 1984; Ward, et. al., 1984).
Interest in Chesapeake Bay SAV communities by scientists, resource
managers and the public has been very high because of the significant
reductions of SAV in many areas compared to luxurious stands that once
prevailed less than 20 years ago (Orth and Moore, 1981, 1983, 1984). The
recently completed Chesapeake Bay Program, funded by the U.S. Environmental
Protection Agency (EPA) , focused research on SAV in the areas of
distribution and abundance, role and value, and factors that may have caused
the decline of SAV (U.S. EPA Synthesis Report, 1982). The research phase of
the Chesapeake Bay Program was completed in 1983 and the implementation
phase is currently in progress.
An early but important consideration in the distribution aspects was
how to determine the abundance of SAV effectively on a baywide basis.
Aerial photography was chosen as the most cost effective and efficient
method of acquiring quantitative information. In 1978 all the shallow water
areas of the bay were flown with medium scale photography (scale 1:24,000).
This mapping study resulted in the publication of a series of topographic
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quadrangles depicting the presence of SAV beds throughout the Chesapeake Bay
region (Orth, et al., 1979; Anderson and Macomber, 1980). During subsequent
years, selected areas of the bay were photographed and/or mapped for SAV but
no complete baywide survey has been conducted since 1978.
Between 1978 and 1984, field surveys in different sections of the bay
or rivers were conducted by the U.S. Geological Survey (USGS), Maryland
Department of Natural Resources (Md.DNR), Northern Virginia Community
College (NVCC) and the Virginia Institute of Marine Science (VIMS), to
monitor the presence and/or absence of SAV in these particular areas. In
addition, researchers at the Harford Conmunity College and the University of
Maryland's Horn Point Laboratories (UMdHPL) had been monitoring SAV
populations in their respective study areas. Studies in the Choptank River
by the UMdHPL have shown a decline in SAV since 1980. However, some surveys
found SAV to be increasing in distribution and abundance in certain
sections, especially in the Potomac River and Susquehanna Flats. Surveys
first by the USGS and then by NVCC showed not only increases in natural
species such as wild celery (Vailisneria americana) and sago pondweed
(Potamogeton pectinatus) but also significant populations of two species
never previously recorded in this area, water stargrass (Heteranthera dubia)
and Hydrilla (Hydrilla verticillata). The latter species was of particular
concern because of its potential rapid growth rate and its ability to spread
and outcompete more desirable species of SAV.
During 1984, SAV beds in the bay were photographed and mapped under
grants by the USEPA and the National Oceanographic and Atmospheric
Administration (NOAA) to VIMS and EPA's Environmental Photographic
Interpretation Center (EPIC). In addition, ground surveys for SAV were
conducted in the Potomac River by the USGS and NVCC and in the entire
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Maryland section of the bay by Md.DNR. This report draws upon not only
information provided by the aerial photography but also data from the
surveys conducted in the Potomac River (Allaire, et al., 1985; Carter, et
al., 1985a; Rybicki, et al., 1985) and the multi-station survey conducted
annually by the Md.DNR. Field observations made in the Susquehanna River
and Flats (Stan Kollar, personal communication) and the Choptank River
(Robert Twilley, personal communication) were used to corroborate and fill
in areas missed by the aerial photography. Unlike the 1978 studies, this
represents a unique effort to combine all the information into one baywide
report of the 1964 sl.atus of SAV.
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SECTION 2
SAV SPECIES
Ten species of submerged vegetation are abundant in the bay. Zostera
marina (eelgrass) is dominant in the lower reaches. Myriophyllum spicatum
(water milfoil), Potamogeton pectinatus (sago pondweed), P_. perfoliatus
(redhead grass), Zannichelia palustris (horned pondweed), Vallisneria
americana (wild celery), Elodea canadensis (common elodea), Ceratophyllum
demersum (coontail) and Najas quadalupensis (southern naiad) are less
tolerant of high salinities and are found in the middle and upper reaches of
the bay (Stevenson and Confer, 1978; Orth, et al., 1979; Orth and Moore,
1981 , 1983). Ruppia maritima (widgeongrass) is tolerant of a wide range of
salinities and is found from the bay mouth to the Susquehanna Flats.
Approximately ten other species are found less commonly and are present
primarily in the middle and upper reaches of the bay and the rivers
(Appendix A). One species presently found in the Potomac River, Hydrilla
verticillata (Hydrilla), has the potential for becoming one of the dominant
species found here (Allaire, et al., 1985; Rybicki, et al., 1985).
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SECTION 3
Aerial Photography
Aerial photography was the principal method used to assess the
distribution of SAV in the Chesapeake Bay and its tributaries in the 1984
study. Pre-determined flight lines for photography of areas that either had
SAV or could potentially have SAV (that is all areas where water depths
were less than 2 m at mean low water) were drawn on 1:25,0000 scale USGS
maps to ensure both complete coverage of S/V beds and inclusion of land
features as control points for mapping accuracy (Fig. 1). Some areas were
not included because of the known lack of SAV in those areas.
The general guidelines used for mission planning and execution are
given in Table 1. These guidelines address tidal stage, plant growth, sun
elevation, water transparency and atmospheric transparency, turbidity, wind,
sensor operation and plotting and allowed for acquisition of photographs
under near optimal conditions. The guidelines are critical because
significant distortion of any one item could significantly decrease the
ability to detect the SAV or to interpret the photography properly as to the
presence or absence of SAV.
The camera used for aerial photography of SAV in Virginia was a
Fairchild CA-8 cartographic camera with a 152 mm (6 1/2 inch) focal length
Bausch and Lomb Metrogon lens. Film was Kodak 24 cm (9 1/2 inch) square
positive Aerochrome MS type 2448. The camera was mounted in a camera port
in the bottom fuselage of the VIMS single engine, fixed high wing De
Havilland Beaver aircraft gelatine. A wratten 1A haze filter was used
inside the cone of the camera to reduce the degrading effect of atmospheric
haze on image quality. Flights were conducted at an altitude of
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Figure 1. Flight lines used for acquisition of aerial photographs of SAV in
1984 for Virginia and Maryland (lines connecting gray squares
represent flight lines used in this survey).
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KILOMETER
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TABLE 1. GUIDELINES FOLLOWED DURING ACQUISITION OF AERIAL PHOTOGRAPHS.
1. Tidal Stage - Photography was acquired at low tide, +/- 0-1.5 ft., as
predicted by the National Ocean Survey tables.
2. Plant Growth - Imagery was acquired when growth stages ensured maximum
delineation of SAV, and when phenologic stage overlap was greatest.
3. Sun Angle - Photography was acquired when surface reflection from sun glint
did not cover more than 30 percent of frame. Sun angle was generally
between 20° and 40° to minimize water surface glitter. At least 60 percent
line overlap and 20 percent side lap was used to minimize image degradation
due to sun glint.
4. Turbidity - Photography was acquired when clarity of water ensured complete
delineation of grass beds.
5. Wind - Photography was acquired during periods of no or low wind. Off-shore
winds were preferred over on-shore winds when wind conditions could not be
avoided.
6. Atmospherics - Photography was acquired during periods of no or low haze
and/or clouds below aircraft. There could be no more than scattered or thin
broken clouds, or thin overcast above aircraft, to ensure maximum SAV to
bottom contrast.
7. Sensor Operation - Photography was acquired in the vertical mode with less
than 5 degrees tilt. Scale/altitude/film/focal length combination permitted
resolution and identification of one square meter area of SAV (surface).
8. Plotting - Each flight line included sufficient identifiable land area to
assure accurate plotting of grass beds.
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approximately 12,000 ft yielding a scale of 1:24,000 for the photograph,
approximating that of a standard U.S. topographic quadrangle.
The SAV photography for the Maryland waters was obtained by Aero Eco
under contract to the Bionetics Corporation (onsite contractor for
EPA/EPIC). The camera used by Aero Eco was a Zeiss Jena LMK 15/2323 with a
153 mm (6.02 inch) focal length Zeiss Jena Lamegon PI/C lens. The film used
was Kodak 24 cm (9 1/2 inch) square positive Aerochrome MS type 2448. The
camera was mounted in the bottom fuselage of Aero Eco's Partenavia P68
Observer, a twin engine high wing reconnaissance aircraft. An
antivignetting filter was olso used. The photography was also acquired at
an approximate altitude of 12,000 feet.
Several problems were encountered during the acquisition of the 1984
aerial photography. Weather patterns consisting of high percentage of cloud
cover and haze appeared to be greater than in past years. This effectively
reduced the time available to collect the SAV imagery. Poor weather
conditions in certain restricted areas, e.g., Dahlgren, Patuxent MAS or
around Smith Island, compounded the problem since access to the airspace
over these areas was limited to certain hours of each day or certain days
only. Both camera and film processing malfunctions, which resulted in the
loss of all or portions of some of the flight lines, occurred in 1984, but,
where, possible, were supplemented with similar aerial photography acquired
in 1983. These problems are further addressed in the next section.
Mapping Process
Fig. 2 gives the location of the topographic quadrangles in the study
area. This area includes all regions with a potential for SAV growth. The
quadrangles are sequentially numbered to allow for more efficient access to
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Figure 2. Location of topographic quadrangles in the Chesapeake Bay and
tributaries for determining distribution of SAV.
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KILOMETER
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TABLE 2. LIST OF USGS 7.5-MINUTE QUADRANGLES IN CHESAPEAKE BAY
SAV STUDY AREA AND CORRESPONDING CODE NUMBERS (SEE FIG.
2 FOR LOCATION OF QUADRANGLES. THOSE TOPOGRAPHIC
QUADRANGLES WITH SAV BEDS CAN BE FOUND IN APPENDIX B).
1. Conowingo Dam, Md.-Pa. 39
2. Aberdeen, Md. 49
3. Havre de Grace, Md. 41 ^
4. North East, Md. 42.
5. Elkton, Md. 43
6. White Marsh, Md. 44
7 . Edgewood, Md. 45
8. Ferryman, Md. 45
9. Spesutie, Md. 47
10. Earleville, Md. 43.
11. Cecilton, Md. 49
12. Baltimore East, Md. 59
13. Middle River, Md. 51
14. Gunpowder Neck, Md. 52
15. Hanesville, Md. 53 .
16. Betterton, Md. 54
17. Galena, Md. 55
18. Curtis Bay, Md. 55.
19. Sparrows Point, Md. 57m
20. Swan Point, Md. 53.
21. Rock Hall, Md. 59.
22. Chestertown, Md. 60.
23. Round Bay, Md. 61.
24. Gibson Island, Md. 52.
25. Love Point, Md. 63.
26. Langford Creek, Md. 64
27. Centreville, Md. 65.
28. Washington West, Md.-DC-Va. 66
29. Washington East, DC-Md. 67
30. South River, Md. 68
31. Annapolis, Md. 69
32. Kent Island, Md. 79.
33. Queenstown, Md. 71m
34. Alexandria, Va.-Md. 72
35. Deale, Md. 73
36. Claiborne, Md. 74.
37. St. Michaels, Md. 75_
38. Easton, Md. 76.
Fort Belvoir, Va.-Md.
Mt. Vernon, Va.-Md.
Lower Marlboro, Md.
North Beach, Md.
Tilghman, Md.
Oxford, Md.
Trappe, Md.
Preston, Md.
Quantico, Va.-Md.
Indian Head, Va.-Md.
Benedict, Md.
Prince Frederick, Md.
Sharps Island, Md.
Church Creek, Md.
Cambridge, Md.
East New Market, Md.
Widewater, Va.-Md.
Nanjemoy, Md.
Mathias Point, Md.-Va.
Popes Creek, Md.
Mechanicsville, Md.
Broomes Island, Md.
Cove Point, Md.
Taylors Island, Md.
Golden Hill, Md.
Passapatanzy, Md.-Va.
King George, Va.-Md.
Dahlgren, Va.-Md.
Colonial Beach North, Va.-Md,
Rock Point, Md.
Leonardtown, Md.
Hollywood, Md.
Solomons Island, Md.
Barren Island, Md.
Honga, Md.
Wingate, Md.
Nanticoke, Md.
Colonial Beach South, Va.-Md,
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continued
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TABLE 2. (continued)
77. Stratford Hall, Va.-Md. 118.
78. St. Clements Island, Va.-Md. 119.
79. Piney Point, Va. Md. 120.
80. St. Marys City, Md. 121.
81. Point No Point, Md. 122.
82. Richland Point, Md. 123.
83. Bloodsworth Island, Md. 124.
84. Deal Island, Md. 125.
85. Monie, Md. 126.
86. Champlain, Va. 127.
87. Machodoc, Va. 128.
88. Kinsale, Va.-Md. 129.
89. St. George Island, Va.-Md. 130.
90. Point Lookout, Md. 131.
91. Kedges Straits, Md. 132.
92. Terrapin Sand Point, Md. 133.
93. Marion, Md. 134.
94. Mount Landing, Va. 135.
95. Tappahannock, Va. 136.
96. Lottsburg, Va. 137.
97. Heathsville, Va.-Md. 138.
98. Burgess, Va.-Md. 139.
99. Ewell, Va.-Md. 140.
100. Great Fox Island, Va.-Md. 141.
101. Crisfield, Va.-Md. 142.
102. Saxis, Va.-Md. 143.
103. Dunnsville, Va. 144.
104. Morattico, Va. 145.
105. Lively, Va. 146.
106. Reedville, Va. 147.
107. Tangier Island, Va. 148.
108. Chesconessex, Va. 149.
109. Parks ley, Va. 150.
110. Urbanna, Va. 151.
111. Irvington, Va. 152.
112. Fleets Bay, Va. 153.
113. Nandua Creek 154.
114. Pungoteague, Va. 155.
115. West Point, Va. 156.
116. Saluda, Va. 157.
117. Wilton, Va.
Deltaville, Va.
Jamesville, Va.
Toano, Va.
Gressitt, Va.
Ware Neck, Va.
Mathews, Va.
Franktown, Va.
We stover, Va.
Charles City, Va.
Brandon, Va.
Norge, Va.
Williamsburg, Va.
Clay Bank, Va.
Achilles, Va.
New Point Comfort, Va.
Cape Charles, Va.
Cheriton, Va.
Savedge, Va.
Claremont, Va.
Surry, Va.
Hog Island, Va.
Yorktown, Va.
Poquoson West, Va.
Poquoson East, Va.
Elliotts Creek, Va.
Townsend, Va.
Bacons Castle, Va.
Mulberry Island, Va.
Newport News North, Va,
Hampton, Va.
Benns Church, Va.
Newport News South, Va
Norfolk North, Va.
Little Creek, Va.
Cape Henry, Va.
Chuckatuck, Va.
Bowers Hill, Va.
Norfolk South, Va.
Kempsville, Va.
Princess Anne, Va.
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the data. Table 2 gives the corresponding names of the 157 quadrangles
shown in Fig. 2.
SAV beds were identified on the photographs using all available
information, including knowledge of aquatic grass signatures on the film,
areas of grass coverage from previous flights, ground information, and
aerial visual surveys. Mylar topographic quadrangles (1:2*1,000) were used
in the mapping process. Delineation of SAV bed boundaries was facilitated
by superimposing on a light table the appropriate mylar quadrangle with the
transparent photograph. SAV boundaries were delineated on the mylar map
with a pencil. Where minor scale differences were evident between the
photograph and quadrangle or where significant shoreline erosion or
accretion had occurred since production of the map, a best fit was obtained,
or shoreline changes were noted on the quadrangle. Areas of SAV beds were
derived from the 1 :24,000 scale topographic quadrangle. Measurements were
made on a Numonics Graphics Calculator, model 1224 for the lower bay. EPIC
utilized a Calma Graphic Interactive Image Analysis System based on a Data
General Eclipse S230 minicomputer for upper bay areas. Each SAV bed was
digitized three times and the area reported as the average of the three.
Each of the three measurements was generally within 5% of the mean.
In addition to the boundaries of the SAV bed, an estimate of percent
cover within each bed was made visually in comparison with an enlarged Crown
Density Scale, similar to those developed for estimating of forest tree
crown cover from aerial photography (Fig. 3)- Bed density was classified
into one of four categories based on a subjective comparison with the
density scale. These were: 1. very sparse; <105&, 2. sparse, 10 to M0%; 3-
moderate, 40 to 70%; or 4. dense, 70-100?. Either the entire bed, or sub-
sections within the bed, were assigned a number (1 to 4) corresponding to
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Figure 3- Crown density scale used for determining density of SAV beds:
very sparse (1), 0-10$; sparse (2), 10-40$; moderate (3), ^0-70?;
dense (H), 70-100*.
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the above density categories. In addition to the density scale, each
distinct SAV unit was given a letter designation for proper identification
for future comparisons.
In order to reduce interobserver variability in both the mapping and
digitizing process, steps were taken to insure quality assurance. Sections
from several areas in both Maryland and Virginia containing SAV were
independently mapped and assigned a density classification. Results were
compared for compatability of mapping effort. In addition, mapped sections
were independently digitized for similar comparisons.
The discussion of the distribution of SAV has been organized into three
zones as established by Orth and Moore (198?). The area between the mouth
of the bay to a line stretching from the mouth of the Potomac River at Smith
Point in Virginia to just above Smith Island and extending across to the
north shore at the mouth of the Big Annemessex River is referred to as the
Lower Bay zone (Fig. 4). The area between the north shore of the Big
Annemessex River and the south shore of the Potomac River to the Chesapeake
Bay bridge at Kent Island is referred to as the Middle Bay zone. The area
between the Chesapeake Bay bridge and the Susquehanna Flats is referred to
as the Upper Bay zone. The salinity within each zone roughly coincides
with the major salinity zones of estuaries; polyhaline (18-25 /oo), Lower
zone; mesohaline (5~18 /oo), Middle zone; oligohaline (0.5-5 /oo), Upper
zone. Although the major rivers and smaller tributaries of the bay have
their own salinity regimes, the distributions of SAV in each river are
discussed within the zone where it connects to the bay proper.
In addition, twenty one major sections of the bay are identified for
more detailed discussion of SAV distribution (Orth and Moore, 1982) (Fig. U,
Table 3). These sections denote relatively distinct parts of the bay that
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Figure ty. Location of upper, middle and lower zones of the Chesapeake Bay
and the 21 major sections used for delineation of SAV
distribution patterns (see Table 3 and text for exact
boundaries).
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TABLE 3. AREA DESCRIPTION FOR EACH OF 21 MAJOR SECTIONS IN THE CHESAPEAKE
BAY HAVING SAV.
Section 1. Susquehanna Flats - all areas between and including Spesutie
Island and Turkey Point at the mouth of the Elk River to include
the Northeast River.
Section 2. Upper Eastern Shore - all areas in the Elk, Bohemia and Sassafras
Rivers and SAV in areas on the eastern shore above the Swan Point
quadrangle.
Section 3- Upper Western Shore - all areas south of Spesutie Island and
north of the bay bridge to include the Bush, Gunpowder, Middle,
Patapsco and Magothy Rivers.
Section 4. Chester River - includes all of the Chester riiver, Eastern Neck,
areas north of the bay bridge on Kent Island and south of Swan
Point but to include SAV on the Swan Pt. quadrangle.
Section 5. Central Western Shore - all areas south of the bay bridge and
north of Holland Point on Herring Bay to include the Severn,
South and West Rivers and Herring Bay.
Section 6. Eastern Bay - all areas south of the bay bridge on Kent Island
and north of Tilghman Island from Green Marsh Point to include
the Wye, East and Miles Rivers, Crab Alley Bay, Prospect Bay and
Poplar, Jefferson and Coaches Islands.
Section 7. Choptank River - all areas south of Tilghman Island from Green
Marsh Point and north of Taylor Island to include the Choptank
and Little Rivers.
Section 8. Patuxent River - all areas in the Patuxent River.
Section 9. Middle Western Shore - all areas south of Holland Point at
Herring Bay and north of Point Lookout on the Potomac River but
not the mouth of the Patuxent River.
Section 10. Lower Potomac River - all areas between the mouth of the Potomac
River to just above the 301 bridge at Nanjemoy Creek.
Section 11. Upper Potomac River - all areas above Nanjemoy Creek to
Washington D.C.
Section 12. Middle Eastern Shore - all areas south of Taylor Island and north
of but not including the Big Annemessex River to include the
Honga, Nanticoke, Wicomico and Manokin Rivers, Fishing Bay,
Bloodsworth and South Marsh Islands.
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continued
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TABLE 3. (continued)
Section 13- Tangier Island Complex - all areas south of and including the Big
Annemessex River and north of but including the northern shore
of Chesconessex Creek to include Smith and Tangier Islands,
Little Anemessex River and Pocomoke Sound.
Section 1^. Lower Eastern Shore - all areas south of but including the
southern shore of Chesconessex Creek and north of Elliots Creek
to include Cherrystone Inlet, Hungars, Nassawadox, Occohannock,
Nandua, Pungoteague and Onancock Creeks.
Section 15. Reedville - includes the area between Windmill Point on the
Rappahannock River and Smith Point at the mouth of the
Potomac River.
Section 16. Rappahannock River Complex - includes the entire Rappahannock
River, Piankatank River and Milford Haven area.
Section 17. New Point Comfort Region - includes the area fronting the bay
from the lighthouse at New Point Comfort north to, but not
including, the bay entrance to Milford Haven.
Section 18. Mobjack Bay Complex - includes the East, North, Ware and Severn
Rivers, the north shore of the Mobjack Bay from New Pt. Comfort
lighthouse to the North River, and the area around Guinea Neck to
include all the SAV around the Guinea Marsh area from the New
Point Comfort quadrangle.
Section 19. York River - all areas along the north shore from Clay Bank
to the Guinea Marsh area and includes SAV from the Achilles
quadrangle facing the York River and along the south shore to
Goodwin Island.
Section 20. Lower Western Shore - includes all areas south of Goodwin Island
to Broad Bay off Lynnhaven Inlet, excluding the James River.
Section 21 . James River - all SAV in the James River including the
Chickahominy River.
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are readily identifiable from a map. Sections 1 through 4 are located in
the Upper Bay zone. Sections 5 through 12 are located in the Middle Bay
zone, and sections 13 tnrough 21 are located in the Lower Bay zone. One •
additional section was added to the original 20 sections denoted by Orth and
Moore (1982) to account for a resurgence of SAV in the tidal freshwater and
transition zone of the Potomac River. This section had little SAV in 1978.
Orth, et al. (1979) chose six sites in the Lower Bay zone to determine
changes in SAV distribution starting in 1937. These sites are Mumfort
Island and Jenkins Neck in the York River, East River in the Mobjack Bay,
Parrott Island in the Rappahannock River, Fleets Bay located between
Windmill Point on the Rappahannock River and Smith Point on the Potomac
River and Vaucluse Shores located on the bayside of the eastern shore just
above Cape Charles (see Orth, et al. (1979) for further details of these
historical sites). Detailed mapping of each historical site was completed
in this study similar to the earlier work to provide a 1984 update.
For those areas currently known to contain some SAV where aerial
photography could not be obtained in 1984 the quadrangles were noted and
determination of SAV abundance from that area was made utilizing low level
aerial reconnaissance, aerial photography of these areas in 1983 or 1984
from other sources, anecdotal information or other field surveys indicating
the presence of SAV in 1981. In these particular situations, distribution
of SAV will be assumed to match what was found in 1978.
Ground Truth and Other Data Bases
For those areas in Virginia where aerial photographic evidence of SAV
beds was inconclusive, photoverification was accomplished by ground truthing
these sites. This was done principally by small boats and divers snorkeling
over the area indicated from the photograph. Since SAV beds in this region
-18-
-------
contain primarily only one or two species that vary little from year to
year, a great deal of ground truth information could be extrapolated from
earlier studies (Orth, et al., 1979, 1982; Orth and Moore, 1982).
In Maryland, ground truth data were provided principally from three SAV
surveys conducted in 1984, from an SAV transplanting project and an ongoing
SAV research project. Two field surveys were conducted in the Potomac
River. The first survey was conducted along the transition zone by the
NVCC (Allaire, et al., 1985). The area covered consisted of 150 miles of
shoreline from Quantico Creek and Chicamuxen Creek in the north to the 301
bridge in the south (Fig. 5). The second survey was conducted by the USGS
(Carter, et al., 1985a; Rybicki, et al., 1985) and included the area from
the Chain Bridge at Washington, D.C. to the Wicomico River just below the
301 bridge (Fig. 6). Earlier surveys of the Potomac River by the USGS
included sections of the river south of the Wicomico River to the mouth of
the Potomac River (Carter, et al., I985b; Haramis and Carter, 1983).
Methods used in these two surveys were similar: either sampling along pre
determined transects or marked grids using modified oyster tongs to estimate
species presence and their standing crop. Visual observations were also
used for species identification. Additional information of these surveys is
available in the above-mentioned reports.
The third survey is the annual large scale multi-station survey
conducted by the Md.DNR. This survey, conducted from June through August,
samples 600+ randomly selected stations in certain areas of the bay from the
Susquehanna Flats to Smith Island. At each station, samples are also
collected with modified oyster tongs and species presence or absence, as
well as standing crop, recorded.
-19-
-------
Figure 5. Location diagram and USLS 1 :24,000 quadrangle index for NVCC
Potomac River SAV shoreline study. Numbers under quadrangle name
indicate number of vegetated grids and the total number of grids
located in that quadrangle (from Allaire, et al., 1985).
-20-
-------
-------
Figure 6. Location of vegetation sampling transects in the tidal and
transition portion of the Potomac River used by the U. S.
Geological Survey for determining SAV distribution patterns (from
Carter, et al., 1985a).
-21-
-------
-------
The SAV transplanting project is being conducted on the Susquehanna
Flats by Stan Kollar of Harford Community College. Information provided by
his work is in the form of species presence by percentage, primarily by
visual estimates.
An SAV research group at UMdHPL headed by Mike Kemp also provided
ground truth data. Robert Twilley of their group annotated maps of their
six study sites on the Choptank River, indicating status of SAV from 1980 to
1984 at each site. No information on percent cover was available.
In addition to 1984 collateral data, a visual aerial survey of the
Susquehanna River, the Northeast River and the upper Bush River was
conducted in 1982 by Dr. Richard Anderson, under contract to Martin
Marietta. SAV data were annotated onto USGS 7.5~minute quadrangles from low
level (300-500 feet) observations. Species information was provided, but no
percent cover values were obtained.
-22-
-------
SECTION 4
RESULTS AND DISCUSSION
The results of the 1984 SAV aerial and ground surveys of the entire bay
and its tributaries showed the presence of extensive stands of vegetation in
a number of locations throughout the bay as well as the continued absence of
SAV beds in areas where they were once abundant.
Table 4 presents hectares of SAV for those quadrangles where vegetation
was observed in 1984 and 1978. Table 5 presents the total hectares of SAV
for each of the 21 sections and the 3 zones for both 1984 and 1978. Table 6
presents the total square meters of SAV in those topographic quadrangles
found in each of the 21 sections. Table 7 presents the square meters of SAV
in each of the four density classes (1-4) for those quadrangles having SAV
only.
Given the constraints of the 1984 data set (see methods and succeeding
sections where problems occurred), it was estimated that there were 15,400
hectares of SAV in 1984 compared to 16,637 found in 1978. Increases of SAV
were observed in the following sections: Susquehanna Flats, Upper Eastern
Shore, Upper Potomac River, Tangier Island Complex, Lower Eastern Shore, New
Point Comfort, Lower Western Shore and York River. Decreases were observed
in the Upper Western Shore, Chester River, Central Western Shore, Eastern
Bay, Choptank River, Patuxent River, Middle Western Shore, Lower Potomac
River, Middle Eastern Shore, Reedville, Rappahannock River, Mobjack Bay and
James River sections. The Lower Bay zone showed an ]Q% increase in SAV
abundance from 1978 to 1984 with 9400 hectares mapped in 1978 and 11,116
hectares mapped in 1984. The Middle Bay zone showed a reduction in SAV of
11% in this time period (4,446 to 984 hectares) while SAV in the Upper Bay
zone increased 13$ (792 to 3168 hectares).
-23-
-------
TABLE 4. TOTAL AREA OF SAV IN HECTARES BY TOPOGRAPHIC QUADRANGLES FOR 1978
AND 1984.
QUANDRANGLE
1. Conowingo Dam, Md.-Pa.
2. Aberdeen, Md.
3. Havre de Grace, Md.
4. North East, Md.
5. Elkton, Md.
6. White Marsh, Md.
7. Edgewood, Md.
8. Ferryman, Md.
9. Spesutie, Md.
10. Earleville, Md.
11. Cecilton, Md.
12. Baltimore East, Md.
13. Middle River, Md.
14. Gunpowder Neck, Md.
15. Hanesville, Md.
16. Betterton, Md.
17. Galena, Md.
18. Curtis Bay, Md.
19. Sparrows Pt., Md.
20. Swan Point, Md.
21. Rock Hall, Md.
22. Chestertown, Md.
23. Round Bay, Md.
21. Gibson Island, Md.
25. Love Point, Md.
26. Langford Creek,
27. Centreville, Md
28. Washington West
29. Washington East
30. South River, Md.
31. Annapolis, Md.
32. Kent Island, Md.
33. Queenstown, Md.
34. Alexandria, Va.-Md.
35. Deale, Md.
36. Claiborne, Md.
37. St. Michaels, Md.
38. Easton, Md.
39. Fort Belvoir, Va.-Md.
40. Mt. Vernon, Va.-Md.
41. Lower Marlboro, Md.
42. North Beach, Md.
Md.
Md.-DC-Va.
DC-Md.
1978
803.67
5.62
.75
10.48
.84
4.67
90
200
9
6
1
33
10
29
127
12
137
139
11
1255
38
,06
.71
• 31
,40
,46
.40
,52
.86
,25
.31
,15
.45
.81
.20
.75
15.
27.
513-
492.
61.
421 ,
366.
1,
14
15
68
10
51
,08
09
,19
1984
0
1741.85
13.31
0
0
49.8H
2.01
411.38
3-47
0
0
0
183.99^
5.
5.
.48
.74
11.88
0
0
18.65
30.13
0
0
7.61
0
599.72
0
0 + +
0
0
0
26.28
89.45
160.40
0
52.25
11.14
0
.91
420.34
0
0
continued
-24-
-------
TABLE 4. (continued)
13.
41.
15.
16.
17.
18.
19.
50.
51.
52.
53.
51.
55.
56.
57.
58.
59.
60.
61 .
62.
63.
61.
65.
66.
67.
68.
69.
70.
71.
72.
73-
71.
75.
76.
77.
78.
79.
80.
81.
82.
83.
81.
85.
86.
87.
88.
Tilghraan, Md.
Oxford, Md.
Trappe, Md.
Preston, Md.
Quantico, Va.-Md.
Indian Head, Va.-Md.
Benedict, Md.
Prince Frederick, Md.
Sharps Island, Md.
Church Creek, Md.
Cambridge, Md.
East New Market, Md.
Widewater, Va.-Md.
Nanjemoy, Md.
Machias Pt. , Md.-Va.
Popes Creek, Md.
Mechanicsville , Md.
Broomes Island, Md.
Cove Pt. , Md.
Taylors Island, Md.
Golden Hill, Md.
Passapatanzy , Md.-Va.
King George, Va.-Md.
Dahlgren, Va.-Md.
Colonial Beach North, Va.-Md.
Rock Pt., Md.
Leonardtown, Md.
Hollywood, Md.
Solomons Island, Md.
Barren Island, Md.
Honga, Md.
Wingate, Md.
Nanticoke, Md.
Colonial Beach South, Va.-Md.
Stratford Hall, Va.-Md.
St. Clements Island, Va.-Md.
Piney Point, Va.-Md.
St. Marys City, Md.
Point -No-Point, Md.
Richland Pt. , Md.
Bloodsworth Island, Md.
Deal Island, Md.
Monie, Md.
Champlain, Va.
Machodoc, Va.
Kinsale, Va.-Md.
continued
-25-
178.15
562.96
61.75
-
-
-
1.58
-
377.08
208.91
18.96
-
-
28.03
191.12
-
13.62
1.91
2.97
-
-
-
2.25
8.32
87.11
22.85
2.11
-
10.51
-
126.91
2.64
-
61.95
5.53
.13
-
-
-
.73
66.07
3.01
9.15
-
-
~~
6.87
23.25
0
0
0
0-n-
0
0
1.12
9.00
0
0
1.59
30.92
121.11
0
0
4.37
3.75
8.55
.12
0
13.11
2.67
25.63
0
0
0
.76
0
5.05
8.81
0
11.26
2.16
0
-
-
-
.38
18.29
0
0
-
-
™
-------
TABLE 1. (continued)
89.
90.
91.
92.
93.
91.
95.
96.
97.
98.
99.
100.
101 .
102.
103.
101.
105.
106.
107.
108.
109.
110.
111.
112.
113.
111.
115.
116.
117.
118.
119.
120.
121 .
122.
123.
121.
125.
126.
127.
128.
129.
130.
131.
132.
133.
131.
St. George Island, Va.-Md.
Point Lookout , Md.
Kedges Straits, Md.
Terrapin Sand Point, Md.
Marion, Md.
Mount Landing, Va.
Tappahannock, Va.
Lottsburg, Va.
Heaths ville, Va.-Md.
Burgess, Va.-Md.
Ewell, Va.-Md.
Great Fox Island, Va.-Md.
Crisfield, Va.-Md.
Saxis, Va.-Md.
Dunnsville, Va.
Morattico, Va.
Lively, Va.
Reedville, Va.
Tangier Island, Va.
Chesconessex, Va.
Parksley, Va.
Urbanna, Va.
Irvington, Va.
Fleets Bay, Va.
Nandua Creek, Va.
Pungoteague, Va.
West Point, Va.
Saluda, Va.
Wilton, Va.
Deltaville, Va.
Jamesville, Va.
Toano, Va.
Gressitt, Va.
Ware Neck, Va.
Mathews, Va.
Franktown, Va.
Westover, Va.
Charles City, Va.
Brandon, Va.
Norge, Va.
Williamsburg, Va.
Clay Bank, Va.
Achilles, Va.
New Point Comfort, Va.
Cape Charles, Va.
Cheriton, Va.
continued
-26-
_
-
156.09
311.18
289.33
-
-
-
-
-
1183.30
510.65
7.18
-
-
-
-
230.10
105.06
182.51
80.35
—
5.31
133.23
181.86
101 .63
—
-
10.13
59.13
106.01
—
—
256.00
63.88
501.19
—
—
-
16.18
—
—
797.92
1096.31
321.12
85.20
_,
-
366.12
187.00
0
-
-
-
—
-
2308.58
807.81
113.01
-
-
-
—
108.56
611.11
808.61
261.80
—
9.33
155.15
315.10
716.76
—
—
0
6.62
367.36
—
—
203.15
30.32
395.26
•"•
—
—
16.18**
~
—
711.50
1092.71
308.32
55.99
-------
TABLE 4. (continued)
135. Savedge, Va.
136. Claremont, Va.
137. Surry, Va.
138. Hog Island, Va.
139. Yorktown, Va. 1.92 0.23
140. Poquoson West, Va. 210.44 216.93
141. Poquoson East, Va. 516.63 687.16
142. Elliots Creek, Va. 44.58 14.48
143. Townsend, Va. 42.70 4.80
144. Bacons Castle, Va.
145. Mulberry Island, Va.
146. Newport News North, Va.
147. Hampton, Va. 218.25 233.15
148. Benns Church, Va.
149. Newport News South, Va. 1.87 0
150. Norfolk North, Va.
151. Little Creek, Va. - 0
152. Cape Henry, Va. * 37.87
153. Chuckatuck, Va.
154. Bowers Hill, Va.
155. Norfolk South, Va.
156. Kempsville, Va.
157. Princess Anne, Va. - -
TOTAL 16,636.39 15,399.70
NOTES: - indicates quadrangle not photographed and assumed to have no SAV
0 indicates quadrangle photographed and no SAV noted
* area not flown in 1978 but most likely had SAV in 1978 based on
data collected in subsequent years
** area not photographed in 1984. Area known to still have SAV. We
made the assumption that the 1984 distribution would be similar
to the 1978 distribution.
+ Information on SAV distribution taken from 1983 aerial
photographs provided by Willie Burton of Martin Marietta Corp.
++ Presence of SAV beds not detected from 1984 aerial photography.
Information provided by Virginia Carter of the USGS for the 1984
Potomac River Shoreline Survey indicated presence of SAV.
-27-
-------
TABLE 5. NUMBERS OF HECTARES OF BOTTOM COVERED WITH SUBMERGED AQUATIC
VEGETATION IN 1978 AND 1984 FOR DIFFERENT SECTIONS WITHIN THE THREE
ZONES IN THE CHESAPEAKE BAY (DATA FOR 1978 FROM ORTH, et al., 1979 AND
ANDERSON AND MACOMBER, 1980.
Section
1. Susquehanna Flats
2. Upper Eastern Shore
3. Upper Western Shore
4. Chester River
5. Central Western Shore
6. Eastern Bay
7. Choptank River
8. Patuxent River
9. Middle Western Shore
10. Lower Potomac River
11. Upper Potomac River
12. Middle Eastern Shore
13. Tangier Island Complex
14. Lower Eastern Shore
15. Reedville
16. Rappahannock River Complex
17. New Point Comfort Region
18. Mobjack Bay Complex
19. York River
20. Lower Western Shore
21 . James River
TOTAL
1978
Hectares Zone
804 +
29 Upper
484 2792
1475 hectares
241
1800
1740 Middle
34 4446
11 hectares
410
0*
210
3759
1991
364
93 Lower
271 9399
1785 hectares
157
925
54
16,637
1984
Hectares Zone
2150
43 Upper
244 3168
731 hectares
0
66
82 Middle
9 984
0 he ct ar es
194
600
33
5447
2232
264
23 Lower
299 11,248
1550 hectares
238
1149
46
15,400
+ 1978 data for Susquehanna Flats remapped and digitized to allow for greater
compatability to 1984 data.
*No aerial photography was taken of this area in 1978 and that the absence of
SAV is based on ground survey observations by the USGS.
-28-
-------
TABLE 6. NUMBER OF SQUARE METERS OF SAV IN EACH QUADRANGLE CONTAINED WITHIN
THE 21 SECTIONS FOR 1981
SECTION
Susquehanna Flats - 1
Upper Eastern Shore - 2
Upper Western Shore - 3
QUADRANGLE
(1)
Conowingo Dam
Aberdeen (2)
Havre de Grace (3)
North East (4)
Ferryman (8)
Spesutie (9)
North East (4)
Elkton (5)
Ferryman (8)
Spesutie (9)
Earleville (10)
Cecilton (11)
Gunpowder Neck
Hanesville (15)
Betterton (16)
Galena (17)
Swan Point (20)
Rock Hall (21 )
White Marsh (6)
Edgewood (7)
Ferryman (8)
Spesutie (9)
Baltimore East (12)
Middle River (13)
Gunpowder Neck (14)
Hanesville (15)
Curtis Bay (18)
Sparrows Point (19)
Round Bay (23)
Gibson Island (24)
AREA
0
0
17,418,496
0
0
4,082.974
21,501,470 sq.m =
2150.1 5 hectares
5310.86 acres
133,146
0
0
22,526
34,703
0
0
54,798
57,422
118,828
0
10,002
431,425 sq.m =
43.14 hectares
106.56 acres
0
498,100
20,136
8,325
0
0
1,839,900
0
0
0
0
76,075
2,442,536 sq.m =
244.25 hectares
603.31 acres
-29-
continued
-------
TABLE 6. (continued)
Chester River - 4
Central Western Shore - 5
Eastern Bay - 6
Choptank River - 7
Swan Point (20)
Rock Hall (21)
Chestertown (22)
Love Point (25)
Langford Creek (26)
Centreville (27)
Kent Island (32)
Queenstown (33)
Round Bay (23)
Gibson Island (24)
South River (30)
Annapolis (31)
Deale (35)
North Beach (42)
Love Point (25)
Annapolis (3D
Kent Island (32)
Queenstown (33)
Claiborne (36)
St. Michaels (37)
Easton (38)
Claiborne (36)
St. Michaels (37)
Easton (38)
Tilghman (43)
Oxford (44)
Trappe (45)
Preston (46)
Sharps Island (51 )
Church Creek (52)
Cambridge (53)
East New Market (54)
Taylors Island (62)
186,456
291,300
0
0
5,997,246
0
77,356
756,388
7,308,746 sq.m -
730.87 hectares
1805.25 acres
0
0
0
0
0
0
0
0
0
185,439
138,088
222,031
111,365
0
656,923 sq.m -
65.69 hectares
162.25 acres
300,482
0
0
68,699
232,542
0
0
44,176
90,017
0
0
85,512
821 ,428 sq.m =
82.1 4 hectares
202.89 acres
-30-
continued
-------
TABLE 6. (continued)
Patuxent River - 8
Middle Western Shore - 9
Lower Potomac River - 10
Lower Marlboro (41)
Benedict (49)
Mechanicsville (59)
Broomes Island (60)
Cove Point (61)
Hollywood (70)
Solomons Island (71)
North Beach (42)
Prince Frederick (50)
Broomes Island (60)
Cove Point (61)
Solomons Island (71)
St. Marys City (80)
Point No Point (81 )
Point Lookout (90)
Nanjemoy (56)
Mathias Point (57)
Popes Creek (58)
Dahlgren (66)
Colonial Beach
North (67)
Rock Point (68)
Leonardtown (69)
Colonial Beach
South (76)
Stratford Hall (77)
St. Clements
Island (78)
Piney Point (79)
St. Marys City (80)
Machodoc (87)
Kinsale (88)
St. George
Island (89)
Point Lookout (90)
Lottsburg (96)
Heathsville (97)
Burgess (98)
0
0
0
43,692
37,518
0
7,616
88,826 sq.m =
8.88 hectares
21.93 acres
0
0
0
0
0
np
np
n£
0
309,243
1,211,162
0
26,712
256,316
0
0
112,561
21 ,600
0
np
np
0
0
np
np
np
np
np
1 ,937,594 sq.m =
193.76 hectares
478.59 acres
-31-
continued
-------
TABLE 6. (continued)
Upper Potomac River - 11
Middle Eastern Shore - 12
Tangier Island Complex - 13
Washington West (28)
Washington East (29)
Alexandria (3*0
Fort Belvoir (39)
Mt. Vernon (10)
Quantico (17)
Indian Head (48)
Widewater (55)
Passapatanzy (61)
King George (65)
Taylors Island (62)
Golden Hill (63)
Barren Island (72)
Honga (73)
Wingate (71)
Nanticoke (75)
Richland Point (82)
Bloodsworth
Island (83)
Deal Island (81)
Monie (85)
Kedges Straits (91)
Terrapin Sand
Point (92)
Marion (93)
0
0
1 ,603,981
9,072
1,203,106
0
0
15,861
0
131.113
5,996,736 sq.m =
599.67 hectares
1181.19 acres
0
1,218
0
50,178
88,116
0
3,810
182,910
0
0
0
0
0
Chesconessex (108) 7
Parksley (109) 2
Tangier Island (107) 6
Ewell (99) 23
Great Fox IslandOOO) 8
Kedges Straits (91) 3
Terrapin Sand
Point (92) 1
Crisfield (101) 1
Marion (93)
Saxis (102)
329,592 sq.m =
32.96 hectares
81 .11 acres
,816,191
,618,039
,111,118
,085,831
,078,128
,661,153
,869,981
,130,088
0
0
-32-
51,167,135 sq.m =
5,116.71 hectares
13,153.37 acres
continued
-------
TABLE 6. (continued)
Lower Eastern Shore - 14
Elliots Creek (142)
Townsend (143)
Cape Charles (1 33)
Cheriton (131)
Franktown (124)
Jamesville (119)
Nandua Creek (113)
Pungoteague (114)
Chesconessex (108)
144,822
48,042
3,083,185
559,874
3,952,565
3,673,577
3,451,033
7,167,565
239,628
22,320,291 sq.m =
2,232.03 hectares
5,513.11 acres
Re.;dville - 15
Fleets Bay (112)
Reedville (106)
Burgess (98)
1,554,487
1 ,085,642
0
2,640,129 sq.m =
264.01 hectares=
652.10 acres
Rappahannock River Complex - 16
New Point Comfort Region - 17
Mathews (123)
Wilton (117)
Deltaville (118)
Irvington (111)
Urbanna (110)
Champlain (86)
Mount Landing (94)
Tappahannock (95)
Dunnsville (1 03)
Morattico (104)
Lively (105)
Saluda (116)
Mathews (123)
New Point
Comfort (132)
72,588
0
66,241
93,276
0
0
0
0
0
0
0
0
232,105 sq.m =
23.21 hectares
57.33 acres
2,985,042
2,985,042 sq.m =
298.50 hectares
737.30 acres
-33-
continued
-------
TABLE 6. (continued)
Mobjack Bay Complex - 18
Achilles (13D
New Point
Comfort (132)
Ware Neck (112)
Mathews (123)
5,297,298
7,342,019
2,031 ,^75
230.562
15,501 ,354 sq.m -
1 ,550.14 hectares
3,828.82 acres
York River - 19
Poquoson West (140)
Yorktown (139)
Clay Bank (130)
Achilles (131 )
West Point (115)
Toano (1?0)
Gressitt (121)
Williamsburg (129)
257,028
2,340
0
2,117,660
0
0
0
0
2,377,046 sq.m -
237.70 hectares
587.1 2 acres
Lower Western Shore - 20
Cape Henry (152)
Hampton (147)
Poquoson East (141)
Poquoson West (140)
Norfolk North (150)
Little Creek (151 )
Kempsville (156)
Princess Anne (157)
378,
,331,
,871,
,912,
714
495
628
278
0
0
0
0
11 ,494,115 sq.m =
1,149.41 hectares
2,839.04 acres
James River - 21
Hampton (147) 0
Newport News
South (149) 0
Norge (128) 464,766
Savedge (135) 0
Claremont (136) 0
Surry (135) 0
Hog Island (138) 0
Yorktown (139) 0
Bacons Castle (144) 0
Mulberry Island (145) 0
-34-
continued
-------
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In order to facilitate the discussion of the distribution of SAV in the
bay, each of the 21 sections in the 3 major zones will be discussed
separately.
1. SUSQUEHANNA FLATS
The distribution of SAV in this section for 1984 was based primarily on
species presence and abundance from Dr. Stan Kollar because of the loss of
imagery of the Flats area. SAV beds on the Flats for 1978 were remapped to
allow for greater comparability to the 1984 data. Instead of mapping each
small bed, the entire area was remapped as distinct units and given a
density classification. Thus, instead of 110 hectares being reported on
1978, the remapping of these data yielded 804 hectares in a density 1
classification. In 1984, the Flats contained sparse patches of SAV
throughout the region which were mapped as one unit and then classified as a
density of 1 (very sparse). Thus, the 1984 survey showed 2,150 hectares in
this section compared to 804 in 1978 (Tables 4-7). The information provided
by Kollar indicates a large increase, albeit only in small patches on the
Susquehanna Flats, from 1978 to 1984. Seven species of SAV were found in
1984, with milfoil, the most abundant, being found in patches throughout the
Flats. Wild celery was the second most important species in this section.
Both species were noted in 1978 with milfoil also being the most common.
Both Hydrilla and water stargrass were noted in 1984 in small isolated
pockets but not in 1978.
The Md.DNR survey sampled 37 stations in 1984 and found no vegetation
in any of these stations (Table 8, Fig. 7). No stations were located in the
Susquehanna River where SAV occurs along the shoreline just north of the
Interstate 95 bridge. The survey did find some vegetation from 1981 to 1983
-39-
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-40-
-------
Figure 7. Trends of occurrence of submerged vegetation at eight of the 26
areas surveyed by the Maryland Department of Natural Resources,
1971-1984.
-41-
-------
cc
<
SNOI1V1S JO lN3083d
-------
but the very sparse nature of SAV on the Flats probably resulted in the SAV
not being sampled in 1984.
It appears from the SAV survey conducted in 1982 by Dr. Richard
Anderson, ground observations by Stan Kollar in 1984 and the 1984 aerial
survey, that SAV is expanding both in the Susquehanna River and the Flats.
2. UPPER EASTERN SHORE
Small, scattered SAV beds were found in this section in the Elk and
Sassafras Rivers in 1984. A total of 43 hectares were mapped in 1984
compared to 29 hectares in 1978 (Tables 4-7) with 30% of the SAV found in
the Elk River of the North East quadrangle. Seven of the 12 quadrangles had
SAV in 1984 compared to 8 in 1978. The small beds found in the Elkton and
Swan Point quadrangles in 1978 were not observed in 1984 while the SAV beds
in the North East quadrangle in 1984 were not present in 1978. Fifteen
stations were sampled in the Elk and Bohemia Rivers by the Md.DNR in 1984
with no vegetation recorded at any of the stations (Table 8). Several of
the stations were located in deep water just off SAV beds evident on the
photography. SAV was found in one of ten stations in the Sassafras River by
this survey. The SAV was milfoil and was noted to be abundant throughout
Lloyd Creek where SAV had been observed in the photographs in 1978. Five
stations on Stillpond had no SAV in the Md.DNR survey although SAV was
observed on the aerial photography in 1984 and 1978 in this area on both the
Hanesville and Betterton quadrangles. Seven additional stations were
sampled in the Howell and Swan Point system and no SAV were found.
-42-
-------
3. UPPER WESTERN SHORE
The 1978 aerial survey indicated there were 484 hectares of SAV. In
1984, several flight lines were lost here due to a malfunction in the film
processing. As a consequence, SAV beds for 1984 were poorly represented in
the Middle, Gunpowder and Bush Rivers where large beds were found in 1978.
However, aerial photography of the Gunpowder River was available for 1983
from Martin Marietta which showed SAV beds in areas similar to 1978. Thus,
SAV information for 1984 was assumed to be similar to 1983. The Middle
River was not flown in 1983 and it could be assumed there was SAV in this
river similar to the 1978 distribution. Th? available 1983-84 photography
showed 244 hectares of SAV in this section. Thus, the distribution of SAV
in 1984 shown here is probably less than what was actually present.
The Md.DNR survey showed vegetation at 3 of 27 stations in the
Gunpowder, Bush, Back and Middle Rivers (Table 8). The three stations that
had SAV were in the Middle River and contained wild celery, milfoil and
Chara sp. In the Magothy River, two of 12 stations had SAV (only horned
pondweed) while no SAV was found in 23 stations in the Patapsco River.
4. CHESTER RIVFR
In 1978, the Chester River section contained a diverse assemblage of 7
species of SAV encompassing 1,475 hectares. These species included milfoil,
redhead grass, wild celery, horned pondweed, widgeongrass and Naiad species.
Eighty-five percent of the SAV in 1978 was in the Langford quadrangle with
the grasses occurring along both shorelines of the lower Chester River. In
1984, 731 hectares of SAV were recorded with 82% found in the Chester River,
Langford quadrangle. There was a decrease of 655 hectares in the Langford
quadrangle from 1978 to 1984. No SAV was mapped for the East and West Forks
of Langford Creek in 1984 because of a film processing malfunction. There
-43-
-------
were 97 hectares found in this area in 1978. There were SAV beds in this
area in 1984, as the Md.DNR survey recorded redhead grass, milfoil and sago
pondweed.
The Md.DNR survey found 19.4$ of their 35 stations in the Chester River
vegetated in 1984 compared to 1 % in 1983 and 0% in 1982 (Table 8, Fig. 7).
However, this was still lower than the 44J of the stations vegetated in the
1978 photo survey. Notes taken during the 1984 Md.DNR survey indicated
large beds of SAV inshore from many of the actual sampling stations as well
as much drift SAV.
5. CENTRAL WESTERN SHORE
No SAV's were noted in this section in 1984, compared with 241 hectares
found in 1978 (Tables 4-7). Aerial coverage of this section in 1984 was
complete. Fifty-seven percent of the vegetation in 1978 in this section was
present in the Severn River with smaller amounts found in the South and
Rhode Rivers. Seven species were present: milfoil, wild celery, redhead
grass, sago pondweed, horned pondweed, widgeongrass and Najas sp.
The Md.DNR survey found no SAV in 1984 in the Severn, South, West and
Rhode River systems (Table 8). Twenty-seven percent of the stations in the
Severn River were vegetated in 1978. This declined to 0% in 1982. Some
vegetation was found in 1983 but declined to 0% again in 1984. Since 1971
the Md.DNR survey has never found SAV in the South-West-Rhode Rivers.
6. EASTERN BAY
In 1984, only 66 hectares of SAV were noted in the aerial photography
for the section. This was a significant decrease from the 1,800 hectares of
SAV recorded in 1978, which was the most abundant section that year (Tables
4-7). Diverse beds of milfoil, redhead grass, sago pondweed, elodea, horned
-44-
-------
pondweed and widgeongrass were found along the shores of Eastern Bay in 1978
but these were considerably reduced by 1984.
The Md.DNR found no vegetation at 8 stations in the Love-Kent Points
systems and SAV at only 3 of 46 stations in the Eastern Bay system in 1984
(Table 8). In 1978, 26.1$ of the stations were vegetated. This percentage
has vacillated between 1978 and 1984, increasing to 34.8$ in 1980 and then
declining to the 6.5$ in 1984. The only species found by the survey in 1984
was widgeongrass.
7. CHOPTANK RIVER
In 1984, only 82 hectares of SAV were noted in the aerial photography
compared with 1740 hectares in 1978. Five species were observed in 1978:
milfoil, sago pondweed, redhead grass, common elodea and horned pondweed.
Large decreases of SAV were noted from 1978 to 1984 in the Claiborne,
Oxford, Sharps Island and Church Creek quadrangles. In 1984, 65$ of the SAV
was found in two quadrangles, Claiborne and Oxford.
The Md.DNR survey found SAV in only 1 of 60 sampled stations in the
Choptank River and no SAV in 19 stations in the Little Choptank River (Table
8). The only species found in 1984 was widgeongrass. In 1978, 28.3$ of the
stations in the Choptank River were vegetated which declined to lower levels
after 1980. No vegetation has been found in the Little Choptank River since
1979. The qualitative surveys of the UMdHPL found SAV at only 2 of their 6
monitoring stations in 1984. In 1980, the year they began monitoring all
six stations were vegetated. .The most dramatic loss of SAV occurred at
Benoni Point (Oxford quadrangle), Dickinson Bay (Trappe quadrangle), and
Todd's Cove (Church Creek quadrangle) during the 1981-82 growing season.
-45-
-------
8. PATUXENT RIVER
In 1984, 9 hectares of SAV were observed from the photography, compared
with 31* hectares in 1978 (Tables 4-7). SAV occurred in the Broomes Island,
Cove Point and Solomons Island quadrangles in 1984. Two species,
widgeongrass and horned pondweed, were found in 1978. The Md.DNR survey
found no SAV in 43 stations and have not recorded any since 1979 when 2% of
the stations were vegetated, the same percentage as 1978 (Table 8).
9. MIDDLE WESTERN SHORE
No SAV was recorded in this section in 1984 compared to 11 hectares
found in 1978 (Tables 4-7). The Md.DNR survey found no SAV in 8 sampled
stations in Curtis - Cove Points system (Table 8). This area is a very
exposed region and would not be expected to support significant stands of
SAV.
10. LOWER POTOMAC RIVER
The Potomac River received more coverage, both from ground and aerial
surveys, than any other part of the bay. Ground surveys by the Md.DNR,
NVCC, and USGS and the 1984 aerial survey provided excellent coverage of the
Distribution of SAV's this year. However, several problems were encountered
with the aerial survey. Five quadrangles were not covered with photography
because of airspace restrictions by the Patuxent NAS: Piney Point, St.
Marys City, Point No Point, St. George Island and Point Lookout. The 1978
aerial survey found no SAV's in these quadrangles. However, Carter, et al
(1985) did find three or four species growing in the St. Marys River during
their 1978-81 survey. Another complication was the timing of the flights
for the Potomac River in 1984. Very poor atmospheric conditions delayed the
flying of the Potomac River flight lines until early November when some of
-46-
-------
the SAV had decline . This resulted in less coverage than that expected
during the growing eason.
In 1984, the . rial survey noted 194 hectares of SAV compared to 410
hectares found in ' 78 (Tables 4-7). SAV was found in the Nanjemoy, Mathias
Point, Dahlgren, C< onial Beach North, Colonial Beach South and Stratford
Hall quadrangles it 1984, similar to what was observed in 1978. Most of the
SAV in 1984 was in he Mathias Point quadrangle (63?) as was the case in
1978 (48*).
The Md.DNR sut -ey sampled 88 stations in the lower section and found
vegetation in only ne, near Blossom Point at the mouth of Nanjemoy Creek.
Wild celery and wi ;eongrass were the only two species observed.
The USGS samp d only the freshwater tidal and transition zone down to
the Wicomico River in 1983 and 1984) (Fig. 6). Table 9 lists the species
found in the vege' ited transects. Wild celery, milfoil, redhead grass,
sago pondweed, and idgeongrass were among the species found in this
section. A compar. on with earlier data collected from 1978-1981 indicated
more vegetated sta' ons and grabs were found on sampled transects in 1984
than in 1981 (Tabl< 10).
The NVCC surv< • also sampled in the transition zone (Fig. 5) in 1984
and found 9 specie in this section (Table 11). These were the same species
found by the USGS . irvey. The distribution of the species found by NVCC is
given in Figs. 8-1 Wild celery was by far the most abundant species found
by the NVCC survey md often was found in 100? coverage.
It is apparen from the data collected by the USGS and NVCC that SAV
was more abundant > lan indicated in the aerial survey. Thus, the smaller
amount of SAV foun in 1984 is most probably due to the timing of the aerial
-47-
-------
TABLE 9. SPECIES OF SUBMERSED AQUATIC PLANTS FOUND ON VEGETATED TRANSECTS
IN THE TIDAL POTOMAC RIVER AND TRANSITION ZONE, 1984.
n.d. is no data available
Transect
Spring
Species
I/
Fall
OR-1R
AD-1R
DM-1R
DM-2R
DM-3R
DM-HR
GC-1R
GC-2R
GC-14R
WC-1R
BC-1T-1
PY-1R
PY-1.5R
PY-2R
PY-3R
PY-4R
PY-5R
PY-7R
PY-8R
PY-1T-1
PY-1T-3
PY-2T-1
MN-9R
MN-10R
Hydr, Vail,
P. pect, Zann
Hydr, P. cris
Hydr
Hydr
Hydr
Hydr, P. pect
Vail, Zann
Cerat
Vail, Zann
Cerat, Heter,
Hydr, Myrio,
Najas g., P. cris
P. pect, Vail
Myrio, Naj as m.
Myrio, Najas m.
Myrio
Vail, Zann
Cerat
Hydr
Cerat, P. pect
P. pect, Vail,
Zann
Heter
Hydr
Cerat, Hydr
Cerat, Hydr
Cerat, Hydr,
Nitella
Cerat, Heter,
Hydr, Myrio,
Nitella, Vail
Heter, Hydr,
Myrio
Myrio, Vail
Vail
Vail
n.d.
Myrio
n.d.
Cerat, Heter,
Hydr, Myrio,
Najas g., Vail
Hydr, Myrio
Najas g.
Najas g.
Heter
Heter, Hydr,
Myrio, Najas g.,
Najas m., Vail
Cerat, Heter,
Hydr, Myrio
Najas g., Vail,
Zann
Myrio,
n.d.
Cerat, Hydr, Myrio
Vail
Vail
-48-
continued
-------
TABLE 9. (continued)
Transect
Species
1 /
Spring
Fall
MN-14T-1
MN-14T-2
MP-3R
MP-4R
NP-2R
NP-3R
NP--HR
NP-5K
NP-bR
NP-7R
NP-8R
NP-9R
NP-10R
NP-11R
NY-3T-3
PO-1T-5
PO-2T-1
PO-2T-2
PO-2T-3
PO-3T-1
WO-5T-1
WD-8T-1
Cerat
Vail
Vail
Myrio, Najas g.,
Vail, Zann
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
Cerat, Myrio
Najas g., P. pus,
Vail
n.d.
n.d.
Vail
Vail
P. perf, Vail
Vail
Cerat, P. pect ,
P. perf, Vail
Vail
Vail
P. perf, Vail
Myrio, P. perf,
Vail
Vail
Cerat, Myrio,
P. pus
Myrio, Vail
Vail
Vail
Vail
Myrio, Vail
P. perf, Rupp
Najas g. , Rupp
1_/Cerat = Ceratophyllum demersum, Heter = Heteranthera dubia,
Hydr = Hydrilla verticillata, Myrio = Myriophyllum spicatum,
Najas g = Najas guadalupensis, Najas m = Najas minor
Nitella = Nitella flexilis, P. cris = Potamogeton crispus,
P. pect = Potamogeton pectinatus, P. pus = Potamogeton pusillus,
Vail = Vallisneria americana, Zann = Zannichellia palustris
P. perf = Potamogeton perfoliatus, Rupp = Ruppia maritima
-49-
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TABLE 10. RELATIVE OCCURRENCE OF VEGETATED TRANSECTS, STATIONS AND GRABS FOR
THE TIDAL POTOMAC RIVER AND ESTUARY, 1978-81 AND 1984.
Relative occurrence as number vegetated/total number
Site
Tidal river
Washington
Channel
transects
stations
grabs
Mattawoman/
Piscataway
Creeks
transects
stations
grabs
Gunston
Cove
transects
stations
grabs
Transition
Maryland
Point
transects
stations
grabs
Wicomico
River
transects
stations
grabs
Vegetated
Date
Fall 1981
1/1
2/4
6/12
Summer 1978
1/34
1 /160
3/480
Fall 1979
0/13
0/65
0/195
zone
Spring 1981
2/4
5/20
8/60
Summer 1981
2/8
3/39
6/117
transects
Date
Fall 1984
1/1
3/4
7/12
Fall 1984
12/34
46/197
84/491
Fall 1984
3/13
14/77
17/231
Spring 1984
2/4
20/38
39/11 4
Fall 1984
2/8
9/44
24/132
Site Vegetated
Date
Pomonkey Spring 1981
Creek
0/4
0/20
0/60
MN-4T-2 Fall 1981
1/1
3/4
7/12
*Nanjemoy/ Summer 1981
Port Tobacco
River
17/17
53/108
1 19/324
transects
Date
Fall 1984
0/4
0/20
0/60
Fall 1984
1/1
1/5
3/15
Fall 1984
16/17
76/135
173/405
*0nly transects which had three or more species in 1978-80 were sampled.
-50-
-------
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-51-
-------
Figure 8. Distribution of wild celery (1), Vallisneria americana, in the
trnsition zone of the Potomac River, 1984 (from Allaire, et al.,
1985).
-52-
-------
-------
Figure 9. Distribution of Hydrilla (1) Hydrilla verticillata, coontail (2)
Ceratophyllum demersum, and milfoil (3) Myriophyllum spicatum in
the transition zone of the Potomac River, 1984 (from Allaire, et
al., 1985).
-53-
-------
-------
Figure 10. Distribution of sago pondweed (1) £. pectinatus, curly pondweed
(2) P_. crispua and redhead gras (3) £. perfoliatus in the
transition zone of the Potomac River, 198H (from Allaire, et
al., 1985).
-54-
-------
-------
Figure 11. Distribution of widgeongrass (1) Ruppia maritima, horned
pondweed (2) Zannichelia palustris, Chara (3) sp., and common
elodea (4) Elodea canadensis in the transition zone of the
Potomac River, 1984 (from Allaire, et al., 1985).
-55-
-------
-------
overflights in this area which were conducted after the peak in standing
crop of SAV.
11. UPPER POTOMAC RIVER
This section may be one of the most interesting of this study because
of its past history and what has been occurring with SAV in the last three
years. This section of the river had been largely devoid of SAV since the
1930's although large beds of SAV were present in the early 1900's (Orth and
Moore, 1984; Carter, et al., 1985b). During the 1978-81 USGS surveys no
species of SAV were found. Since 1981, however, not only has there been a
dramatic increase in many of the native species, but also three species,
Hydrilla verticillata, Heteranthera dubia, and Najas minor, not present in
earlier surveys (Carter, et al., 1985a,b) were reported. This increase has
occurred in the reach between Alexandria, Virginia, and Marshall Hall,
Maryland. Fig. 12 shows the species diversity of SAV in the tidal Potomac
River in 1983 while Fig. 13 shows the increase in species diversity in this
same area in 1984. Comparison of the 1984 transect data (Table 9, Fig. 6)
with that of the 1978-81 survey clearly shows the increase in the upper
tidal river (Table 10). All of the increase which occurred in the
Mattawoman/Piscataway Creeks and the Gunston Cove regions was above Marshall
Hall. There is still virtually no SAV in the reach between Marshall Hall
and Quantico, Virginia.
The presence of Hydrilla is notable given the growth potential of this
species. Hydrilla is a fast growing exotic plant from Southeast Asia. It
is considered a nuisance in California, Florida and other southeastern
states because it forms thick mats of vegetation which interfere with
recreational use of the water. It reproduces both vegetatively and
sexually, and overwinters by tubers and turions. In 1981 , a small
-56-
-------
Figure 12. SAV species diversity in the tidal Potomac River, 1983 (from
Carter, et al., 1985a).
-57-
-------
77° 15'
717°
39°
45'
EXPLANATION
Number of species
10 MILES
I
10 KILOMETERS
-------
Figure 13. SAV species diversity in the tidal Potomac River, 1984 (from
Carter, et al., 1985a).
-58-
-------
77«|l5'
7|7"
39°
_38°
45'
MARYLAND
EXPLANATION
Number of species
Mallows Bay
0
1-2
3-4
>4
10 MILES
I
I
10 KILOMETERS
-------
population of Hydrilla was found in Dyke Marsh, Virginia. In 1982, the
Department of Agriculture made a positive identification and discovered that
Hydrilla was widespread in lentic environments in the Washington, D.C. area.
By 1983, Hydrilla was firmly established in the reach above Marshall Hall,
with its greatest population in the Dyke Marsh area on the Virginia side of
the river (Fig. 14). In 1984, it filled in along the Maryland and Virginia
shorelines, with the largest populations along the shoreline adjacent to
and across from Dyke Marsh (Fig. 15). In many parts of the tidal river, it
is found growing with many other species and composes less than 10 percent
of the total plant material. There is concern that Hydrilla might
outcompete other desirable SAV species in the Potomac River.
Allaire et al. (1985) also reported Hydrilla in this section (Table 11)
but much farther south than that reported by Rybicki et al. (1985). It was
prevalent in the marsh guts on the Maryland side of the river down to
Mathias Point and present in 1 3 of the 186 grids sampled (Fig. 9). One
specimen was found floating in a tributary of Potomac Creek, and three
plants were found rooted behind the marsh at Aquapo Beach on Aquia Creek.
No Hydrilla was found rooted in the main part of the Potomac River in the
transition zone.
Allaire et al. (1985) also found other species present in this section
(Table 11, Figs. 8-11). No vegetation was found in the Quantico quadrangle
while Indian Head, Widewater, Passapatanzy and King George had 20%, 2Q%, 32%
and 12? of the grids vegetated, respectively. Coontail and wild celery were
the most abundant species evident.
The Md.DNR survey sampled 52 stations in this section in 1984 and found
vegetation in only one, Broad Creek. Hydrilla was present in the three
samples collected from this site.
-59-
-------
77"h5'
39°
45'
EXPLANATION
Percent Cover
10-40
<5 (occasional patches)
10 MILES
I
10 KILOMETERS
-------
The 1984 aerial survey confirmed the presence of the SAV beds in this
section (Tables 1-7) with 631 hectares mapped from the photography. Of the
11 quadrangles in this section, SAV was present in six, with 67% found in
the Mt. Vernon quadrangle and 25? in the Alexandria quadrangle. As
indicated from the ground surveys of the USGS, the SAV was a mixture of many
species, including Hydrilla. No SAV was mapped for this section in 1978.
The cause for the increase in SAV in this section is not known but may
be related to nutrient changes in this region. There has been a dramatic
decrease in phosphate loading from the Blue Plains sewage treatment plant
since the late 1970's. In 1983, Blue Plains began nitrification, changing
the predominant nitrogen species in the river from ammonia to nitrate. At
the same time, Blue Plains reduced the suspended solids output from the
plant (Table 12). Secchi depths in the upper tidal river were significantly
higher in 1983 than in the 1978-81 (Table 13). There were blue-green algae
blooms during the summer of 1983 and 1981, but the 1983 bloom did not reach
the Wilson Bridge until nearly September, moving upriver from the Quantico
area. In 1981, the river discharge was higher and the bloom never reached
the upper tidal river. These recent algal blooms have thus had little
effect upon the water clarity and light available for SAV growth in this
section.
12. MIDDLE EASTERN SHORE
In 1981, there was only 32.9 hectares of SAV in this section compared
to 210 hectares found in 1978 (Tables 1-7). The earlier aerial survey found
only four species present: widgeongrass, horned pondweed, sago pondweed and
eelgrass. This section comprises a large area of the mid-bay section with
many areas having large, broad flats (Bloodsworth and South Marsh Islands)
or coves that would be conducive for SAV growth, yet very little is present
-62-
-------
TABLE 12. TOTAL SUSPENDED SOLIDS OUTPUT FROM THE PRIMARY OUTLET OF BLUE
PLAINS SEWAGE TREATMENT PLANT, 1982 AND 1983.
Month
April
May
June
July
August
September
October
[Monthly mean in mg/L (number
1982
9.8 (30)
1.16 (3D
7.09 (30)
U.82 (31 )
5.18 (3D
6.7 (30)
5.24 (3D
of observations)]
1983
1.2 (20)
1.0 (3D
1.3 (30)
1.1 (30)
1.2 (3D
1.2 (30)
1.3 (3D
-63-
-------
TABLE 13. SECCHI DEPTH IN THE UPPER AND LOWER TIDAL RIVER, JULY-OCTOBER,
1978-81 AND JULY-OCTOBER, 1983 (SE = STANDARD £RROR, N = NUMBER OF
OBSERVATIONS).
[Depth in cm]
Location/Date
Upper tidal river
July-October, 1978-81
July-October, 1983
July-August, 1983
Lower tidal river
July-October, 1978-81
July-October, 1983
July-August, 1983
Mean
51.8
85.5
87.3
38.8
50.8
50.8
SE
3.28
4.69
5.20
1 .29
4.96
4.96
N
38
48
39
72
13
13
-64-
-------
today in this section. Fifty-five percent of the SAV in this section in
1984 occurs in the Bloodsworth quadrangle with the remaining beds located in
Golden Hill, Honga, Wingate and Richlend Point quadrangles. No SAV occurs
in 8 quadrangles.
The Md.DNR survey sampled 169 stations in this section, examining sites
in the James-Barren Island system, Honga River, Fishing Bay, Nanticoke -
Wicomico River, Manokin River and Big Annemessex River (Table 8, Fig. 7).
Only 1 of 15 stations in the Manokin River had SAV (widgeongrass) , while 1
of 12 stations in the Big Annemessex River was also vegetated with
widgeongrass (Table 8, Fig. 7). All the stations sampled in the other areas
were unvegetated.
13. TANGIER ISLAND COMPLEX
This section contains the second largest number of quadrangles that
contain SAV (8) and is the section with the most SAV present. In 1984,
5,376 hectares were mapped compared to 3,759 hectares in 1978, a 43$
increase (Tables 4-7). The number of hectares in this section was over
twice as much as in the next largest section, the Lower Eastern Shore, which
has 2,232 hectares. Of the SAV mapped in the Lower Bay zone, 48? is located
in the Tangier Island Complex.
The SAV beds are concentrated in several distinct areas: adjacent to
Big Marsh between Chesconessex Creek and Deep Creek, on the west side of
Webb and Halfmoon Island, the east side of Fox Islands around Cedar Straits
and the areas in and around Tangier and Smith Islands and the large broad
shoal area between the two islands. Seventy-three percent (3,909 hectares)
of the SAV in this section is located in the Tangier-Smith Island region.
This, by far, is the section of the bay that has the densest concentration
of SAV.
-65-
-------
The Md.DNR survey of Smith Island indicated a decline in SAV from 1983
to 1984, when only 29.4? of the 17 stations were vegetated. This is in
contrast to the photographic data showing a large increase in the Smith
Island area. A comparison of the 17 DNR station locations and the
distribution maps from aerial photography indicated that the twelve
unvegetated stations were adjacent to existing beds outlined in the
photographs and that the five vegetated stations were in areas classified as
dense from the photography.
Two other areas were field checked by the Maryland survey. No SAV was
found in the 22 stations in the Pocomoke Sound area although small.
scattered beds were aerially mapped very close to the shoreline, well
inshore of the sampled stations. In the Little Annemessex River, the
Maryland survey showed no SAV in 8 sampled stations. The aerial survey
showed beds located on both shores of the river in a narrow band and well
inshore of several of the Maryland stations. The SAV in the Crisfield
quadrangle increased from 7 to 107 hectares from 1978 to 1984 in the aerial
survey while the Maryland survey has shown no increase and very little
vegetation in this region.
14. LOWER EASTERN SHORE
This section contains the largest number of quadrangles that contain
SAV (9) and is the second largest section in SAV area in the Lower Bay zone.
In 1984, 2,232 hectares, consisting of eelgrass and widgeongrass, were
mapped compared to 1,991 hectares in 1978, an increase of 12$ (Tables 4-7).
The largest beds were found around Cape Charles at the mouth of Cherrystone
Inlet, and at the mouths of Hungars and Mattawoman Creeks (also called
Vaucluse Shores), Occahannock Creek, Craddock Creek, Pungoteague Creek and
Onancock Creek. The areas between these creek systems are sparsely
-66-
-------
vegetated or unvegetated because of the exposed nature of these broad sand
flats.
SAV in the Vaucluse Shores historical area (includes part of Hungars
and Mattawoman Creeks) (see Orth, et al., 1979, for a detailed description
of the site) has remained relatively stable since 1978 (Table 14, Fig. 16),
although changes prior to 1978 were a result of the dynamic nature of the
sand bars and spits in this region. The historical area was also the site
where seven transects were made in 1978 for species distribution. These
transects showed widgeongrass in the shallowest areas, eelgrass in the
deeper sites and both species at intermediate depths. Horned pondweed has
also been found mixed with widgeongrass in the shallowest depths.
15. REEDVILLE
In 1984, 264 hectares of SAV were observed in the section compared to
the 364 hectares mapped in 1978 (Tables 4-7). Most of the beds, which are
found throughout the section, were classified as sparse or very sparse
(Table 7). This section contains the Fleets Bay historical site where 101
hectares were mapped in 1984 compared to 73 hectares in 1978 (Table 14, Fig.
16). SAV coverage actually decreased from 1978 to 1980 but increased in
1981. This increase from 1981 to 1984 was noted to occur in areas that were
classified as sparse or very sparse.
16. RAPPAHANNOCK RIVER COMPLEX
Only 23 hectares of SAV were found in this section in 1984 compared to
93 in 1978 (Tables 4-7). Several small but dense beds are present in the
Milford Haven area, remnants of the dense beds present in the early 1970's.
The other beds are small and sparse, located along the north shore of the
Rappahannock River. No SAV was observed in the Piankatank River. There
were no SAV beds in the Parrott Island historical area (Table 14, Fig. 16).
-67-
-------
TABLE 14. AREAS OF SAV AT HISTORICAL MAPPING SITES (LOWER BAY ZONE) 1937~1984
Parrott Islands
Date
1937
1951
1960
1968
1974
1978
1980
1981
1984
<10$
0
394,797
411,306
92,064
0
0
0
0
0
10-40?
297,024
778,146
631,566
1 ,354,110
2,922
22,872
0
0
0
Area m2
40-70$
1,598,268
1 ,222,410
547,014
1 ,205,628
7,710
0
0
0
0
70-100$
0
1 ,158,384
1,947,372
124,374
0
0
0
0
0
Total
1 ,895,292
3,553,737
3,537,258
2,776,176
10,632
22,872
0
0
0
Fleets Bay
Date
1937
1953
1961
1969
1974
1978
1980
1981
1984
<10$
0
1 ,488,258
1 ,572,612
1,436,403
105,714
167,688
0
0
232,164
10-40$
1,385,424
597,354
1,330,140
1 ,938,660
1 ,624,884
528,918
121 ,890
683,250
730,680
Area m2
40-70$
548,076
591 ,018
1,643,892
1 ,592,170
1,325,040
33,592
26,040
9,816
33,318
70-100$
744,864
284,232
884,280
270,372
0
0
2,472
13,986
14,556
Total
2,678,364
2,960,862
5,430,924
5,237,605
3,055,638
730,198
150,402
707,052
1 ,010,718
Mumfort Islands
Date
1937
1953
1960
1971
1974
1978
1980
1981
1984
<10$
0
151 ,728
0
0
0
0
0
0
0
10-40$
495,060
699,252
258,210
685,536
127,488
0
0
0
0
Area m2
40-70$
397,368
106,356
1 ,880,238
1 ,088,976
23,826
0
0
0
0
-68-
continued
70-100$
23,832
1 ,461 ,846
0
0
0
0
0
0
0
Total
91 6,260
2,419,182
2,138,448
1 ,774,512
151,314
0
0
0
0
-------
TABLE 14. (continued)
Jenkins- Neck
Date
1937
1953
1960
1971
1974
1978
1980
1981
1984
<10*
0
426,480
140,448
0
93,972
132,714
60,810
0
72,876
10-40$
1 ,180,200
647,112
794,178
278,586
303,804
299,760
191 ,605
0
289,388
Area mz
40-70*
820,612
717,180
639,012
2,350,380
1 ,599,228
671 ,616
690,968
763,194
563,268
70-100*
32,520
1 ,811 ,832
2,067,948
33,792
93,912
162,408
179,589
309,012
954,360
Total
2,033,332
3,602,604
3,641,586
2,662,758
2,090,916
1 ,266,498
1,122,972
1 ,072,206
1 ,879,892
East River
Date
1937
1953
1963
1971
1974
1978
1980
1981
1984
<10*
1 ,024,010
591 ,840
31,032
0
509,730
47,860
191 ,520
0
496,445
10-40*
809,770
1 ,158,490
1 ,916,530
2,007,460
348,820
515,000
451,351
96,174
739,836
Area m2
40-70?
1,357,790
1 ,394,740
2,3^0,480
2,253,080
1 ,955,130
1 ,864,850
808,842
1 ,183,542
' 706,736
70-100*
85,530
1 ,742,050
0
96,620
0
0
158,634
198,474
88,458
Total
3,277,100
4,887,120
4,288,042
4,357,160
2,81 3,680
2,427,710
1 ,610,347
1 ,478,190
2,031,475
Vaucluse Shores
Date
1938
1948
1955
1966
1972
1978
1980
1981
1984
<10*
0
506,706
1 ,938,258
452,940
286,554
187,728
359,551
327,786
0
10-40?
1 ,120,284
1 ,171 ,884
0
402,324
364,764
507,054
7,098
97,950
15,792
Area m2
40-70*
1 ,451 ,392
1 ,715,556
528,996
2,53^,178
2,515,740
80,872
697,842
355,344
1,137,882
70-100*
1 ,480,128
0
1 ,238,124
604,176
391 ,770
2,036,526
1,783,938
1 ,852,392
1 ,731 ,678
Total
4,051 ,804
3,994,146
3,705,378
3,993,618
3,558,828
2,812,180
2,848,429
2,633,472
2,885,352
-69-
-------
Figure 16. Trends in areal coverage of SAV at six intensively mapped areas
in the lower Chesapeake Bay, 1937-1984.
-70-
-------
S3dVlD3H
-------
17. NEW POINT COMFORT REGION
Dense beds of SAV were found in this section in 198*1 from New Point
Comfort Lighthouse to just north of Horn Harbor (Tables 4-7). Two hundred
ninety-nine hectares of SAV were mapped in 1984 compared to 271 hectares in
1978. Prominent features of this section are the distinct, unvegetated sand
bars found parallel to the shoreline with SAV found in the troughs between
successive bars.
Two transects were made in the area in 1978 for species distribution.
Both eelgrass and widgeongrass were present, with widgeongrass in the
shallower depths a Long the transect and eelgrass in the deeper zones.
18. MOB JACK BAY COMPLEX
This section contains one of the largest amounts of SAV in the lower
Bay zone. In 1984, 1,550 hectares were mapped compared to 1785 hectares in
1978 (Tables 4-7). SAV beds, consisting of eelgrass and widgeongrass, are
present along the shorelines of the entire Mobjack Bay and three of the four
tributaries: Severn, Ware and North Rivers. Little SAV is present in the
East River. One of the largest and densest beds found along the western
shore of the lower bay is present around the Guinea Marshes in the New Point
Comfort quadrangle.
Four transects on the Achilles quadrangle (Browns Bay and Ware Point)
and two in the New Point Comfort quadrangle (mouth of East River) were made
in 1978. Data from these transects also showed widgeongrass in the
shallowest depths and eelgrass predominantly in the deeper locations with
the two found together at intermediate depths.
SAV in the East River historical area (see Orth, et al., 1979, for a
detailed description of this site) decreased from 1978 to 1984, but
examination of data collected in 1980 and 1981- showed SAV increasing 37%
-71-
-------
from 1981 to 1984 (Table 14, Fig. 16). Observation of this area has shown
the increase also occurring from recruitment and growth of seedlings.
19. YORK RIVER
There were 238 hectares of SAV mapped in 1984 compared to 157 hectares
in 1978, an increase of 52% (Tables 4-7). The major SAV beds, consisting of
eelgrass and widgeongrass, in this section are present on the north side of
lower York River in the Achilles quadrangle. There are no SAV beds above
Gloucester Point in the Clay Bank quadrangle. One small bed present in the
Yorktown quadrangle in 1984 near Gloucester Point was transplanted to this
area in the fall of 1983 (Orth, unpublished data). Monitoring of the lower
York River has shown these areas to be increasing as a result of seedling
recruitment from adjacent, upstream beds, followed by rapid growth of these
seedlings.
There was still no SAV present in the Mumfort Island historical area
while SAV increased 48$ from 1978 in the Jenkins Neck historical area (Table
14, Fig. 16) (see Orth, et al., 1979, for a detailed description of the
sites). The increase is a result of seedling establishment and growth.
Two additional 0.25-hectare beds were transplanted near Gloucester
Point in the Achilles quadrangle, one in the fall of 1982 and the second in
the fall of 1983- The 1982 planting was done on 1.0 and 0.5 m centers using
eelgrass. The bed has grown almost into one unit in less than three years.
The 1983 eelgrass planting was conducted on 2 m centers and the units have
not coalesced but are still present and growing very well. The 0.25-hectare
plot in the Yorktown quadrangle was also planted on 2 m centers.
20. LOWER WESTERN SHORE
The SAV in this section, consisting of eelgrass and widgeongrass, was
found in the Broad Bay area off Lynnhaven River, Back River, Drum Island
-72-
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Flats between Back and Poquoson Flats, Poquoson River and on the south side
of Goodwin Island. There were 1,1*19 hectares of SAV mapped in 1984 compared
to 925 hectares in 1978 (Tables 4-7). The SAV beds in the Broad Bay area
(37.87 hectares-Cape Henry quadrangle) were not mapped in 1978, although it
is most likely they were present that year since subsequent surveys from
1980 through 1983 has shown the persistence of this vegetation. The
distribution of vegetation in the Hampton and Poquoson West quadrangles
remained similar while there was a 33? increase in SAV (51 6 to 687 hectares)
in Poquoson East quadrangle. This increase occurred on the Drum Island
Flats adjacent to existing beds of SAV that, have persisted since the early
1970's. Most of the beds in this section have been classified as moderate
(40 to 70%) or dense (70 to 100?) (Table 7).
21 . JAMES RIVER
The small patches of SAV, consisting of eelgrass, in the Hampton Roads
area present in 1978 had disappeared by 1980 and were still absent in 1984
(Tables 4-7). The remaining SAV beds identified in 1978 were located in the
Norge quadrangle, and although this area was not photographed and mapped in
1984, an aerial reconnaissance survey of the area in late 1984 indicated
that these beds were still present that appeared very similar to the 1978
distribution maps. We have assumed here that the 1984 total would be
similiar to the 1978 total. These beds occur as narrow fringing beds
located along the edge of the marsh channels at water depths of less than 1
meter. The dominant species here are coontail, several Naiad species and
common elodea (Orth, et al., 1979).
-73-
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SECTION 5
SUMMARY AND CONCLUSIONS
The distribution of beds of submerged aquatic vegetation in the
Chesapeake Bay and tributaries in 1984 was examined using both aerial
photographic and ground surveys. Aerial photographs were used to map SAV
bed outlines onto topographic quadrangles while ground surveys provided both
photo verification of the SAV beds and species identification. To delineate
SAV beds on a baywide basis, the distribution of SAV was divided into three
major zones and 21 sections within the three zones. The areas mapped were
displayed on 157 topographic quadrangles. The quadrangles include all areas
with a potential for SAV growth in the bay region. The distribution data
for 1984 were compared to data collected from a baywide survey conducted in
1978.
In 1984, SAV was found occupying 15,400 hectares of bottom. Of this
total, 18.7? of the beds were classified as very sparse (<10? coverage),
18.6% as sparse (10-40?), 27.3? as moderate (40-70?) and 35.5? as dense (70-
100?). In 1984, 20.6? of the SAV beds were located in the Upper Bay zone,
6.3? in the Middle Bay zone and 73.0? in the Lower Bay zone. The coverage
of SAV in 1984 was less than the total found in 1978 (16,637 hectares). In
the 1978 survey, 16.8? of the vegetation was found in the Upper Bay zone,
26.7? in the Middle Bay zone and 56.5? in the Lower Bay zone. Increases in
SAV coverage from 1978 to 1984 were measured in 8 of the 21 sections:
Susquehanna Flats, Upper Eastern Shore, Upper Potomac River, Tangier Island
Complex, Lower Eastern Shore, New Point Comfort Region, York River and Lower
Western Shore. Decreases were measured in 1 3 of the 21 sections: Upper
Western Shore, Chester River, Central Western Shore, Eastern Bay, Choptank
River, Patuxent River, Middle Western Shore, Lower Potomac River, Middle
-74-
-------
Eastern Shore, Reedville, Rappahannock River Complex, Mobjack Bay Complex
and James River.
In the Upper Bay zone, although there was an increase noted, all of
this occurred on the Susquehanna Flats where 95$ of the area was classified
as very sparse «10/K coverage). Independent aerial and ground surveys of
this area in 1982 and 1984, respectively, indicate that there has been an
expansion of SAV in this section since 1978 but that the vegetation is very
patchy and not readily apparent on higher altitude photography. Most of the
SAV observed on the Susquehanna Flats was Myriophyllum spicatum (milfoil)
with Vailisneria americana (wild celery) occurring in lesser abundance. A
total of only 2 species were noted in the ground surveys in 1984, in
contrast to the 15 species found here in the late 1950's (Bayley, et al.,
1978; Orth and Moore, 1984). Reductions of SAV were recorded in the Upper
Eastern Shore and Upper Western Shore sections. Although, there was some
loss of the aerial imagery from these two sections, the Md.DNR ground survey
showed reductions of SAV in these areas.
SAV in the Middle Bay zone was reduced from 1978 to 1984: 4,446 to
984 hectares, respectively. Seven of the eight sections showed a decline of
SAV. In one of these sections, Lower Potomac River, aerial photography
obtained late in the season may have resulted in an underestimation of SAV
abundance. Ground surveys by USGS and NVCC personnel documented SAV
presence at a number of stations in areas that did not show SAV in the
aerial photography. Given the survey information for 1984, and what was
observed for the entire Potomac River in 1984, the actual abundance of SAV
in the Lower Potomac River was at least equal to that recorded in 1978. The
Upper Potomac River section was the only area of the river to show a
significant increase. No aerial photography of the Upper Potomac was
-75-
-------
obtained in 1970 and ground surveys found no SAV through 1981. From 1981 to
1984, 631 hectares of river bottom became vegetated with SAV. This increase
includes not only many native species but also significant populations of
two species not recorded in earlier surveys of the river: Hydrilla
verticillata (Hydrilla) and Heteranthera dubia (water stargrass). Since
Hydrilla has become a problem species in other areas of the U.S., there is
concern over its increase to nuisance levels in certain sections of the
Potomac. The river should be carefully monitored in succeeding years to
follow the growth of Hydrilla as well as other native species.
The Lower Bay zone showed an increase of 1778 hectares since 1978 (19?)
with most of the increase (82%) occurring in the Tangier Island Complex.
Increases in SAV beds in the York River have been observed to occur from
seed recruitment from nearby vegetated areas. This increase was also noted
in 3 of the 6 historical sites in this zone: Jenkins Neck, East River and
Fleets Bay. As in 1978, no SAV was observed at two sites (Mumfort Island
and Parrott Island). The sixth site, Vaucluse Shores, has remained
relatively stable since 1978.
In summary, although the total amount of SAV in the bay in 1984 is
somewhat less than that found in 1978, both increases and decreases have
been observed in particular sections. Most of the decrease has occurred in
the region from just below the Susquehanna Flats to Smith Island. This
decrease in vegetation during the last 6 years has also been noted by the
Md.DNR vegetation survey (Table 8, Fig. 17). The number of sampled stations
with SAV has continued to decrease from earlier years. In 1984, only H.0%
of the stations were vegetated compared to 9.5% in 1978. Seventeen of 26
areas were without any SAV compared to 12 in 1978. However, certain
procedures used in the Maryland DNR survey, such as stations located in
-76-
-------
Figure 17. Trends in occurrence of SAV in the Maryland portion of the
Chesapeake Bay, 1971-1984. Values represent the percentage of
stations with vegetation (N = 644) and the percentage of
unvegetated areas (N = 26).
-77-
-------
SV3HV JO !N30y3d
(T
<
UJ
SNOI1V1S dO lN30H3d
-------
waters too deep to support SAV growth, may be resulting in a skewed or an
unrealistically low impression of total SAV presence.
Increases in SAV have been noted in the Upper Potomac River,
Susquehanna Flats and at a number of locations in the Lower Bay zone. The
increase of SAV in the upper Potomac River may be related to nutrient
changes in this part of the river, primarily from a reduction in phosphate
loading and suspended solids from the Blue Plains sewage treatment plant and
the initiation of nitrification in 1983. The causes for the increase in SAV
in several sections and decreases in others is not known, but annual
monitoring of SAV populations along with the monitoring of nutrient and
light parameters at these areas is essential for generating any significant
correlative data. In addition, the success of various transplant efforts by
both states should be examined carefully with regard to the nutrient and
light regimes found in those river systems where the transplanting is being
conducted. These data will be critical in understanding the success at
these sites.
-78-
-------
SECTION 6
LITERATURE CITED
Allaire, R. A., K. W. Potts, T. P. Sheehan and N. R. Sinclair. 1985.
Shoreline survey of submersed aquatic vegetation including Hydrilla in
the transition zone of the Potomac River during the summer and fall of
1984. Final Report. U.S. Army Corps of Engineers. Contract No. DACW
31-82-D-007. 40 pp.
Anderson, R. R. and R. T. Macomber. 1980. Distribution of submersed
vascular plants Chesapeake Bay, Maryland. U.S. EPA. Final Report.
Chesapeake Bay Program. Grant No. R805970. 126 pp.
Bayley, S., V. D. Stotts, P. F. Springer and J. Steenis. 1978. Changes in
submerged aquatic macrophyte populations at the head of the Chesapeake
Bay, 1958-1974. Est. 1:171-182.
Carter, V., N. B. Rybicki, R. T. Anderson, T. J, Trombley and G. L. Zynjuk.
1985a. Data on the distribution and abundance of submersed aquatic
vegetation in the tidal Potomac River and transition zone of the
Potomac estuary, Maryland, Virginia, and the District of Columbia,
1983 and 1984. U.S. Geological Survey Open-File Report 85~82. 65 pp.
Carter, V., J. E. Paschal, Jr. and N. Bartow. 1985b. Distribution and
abundance of submersed aquatic vegetation in the tidal Potomac River
and estuary, Maryland and Virginia, May 1978 to November 1981. U.S.
Geological Survey Water-Supply Paper 2234A. 54 pp.
Haramis, G. M. and V. Carter. 1983- Distribution of submersed aquatic
macrophytes in the tidal Potomac River. Aquat. Bot. 15:65-79.
Kemp, W. M., W. R. Boynton, R. R. Twilley, J. C. Stevenson and L. G. Ward.
1984. Influences of submersed vascular plants on ecological processes
-79-
-------
in upper Chesapeake Bay. pp. 367-394. In: V. S. Kennedy (ed.). The
estuary as a filter. Academic Press, Inc., New York.
Orth, R. J., K. L. Heck, Jr. and J. van Montfrans. 1984. Faunal
communities in seagrass communities: A review of the influence of
plant structure and prey characteristics on predator-prey
relationships. Est. 7:339~350.
Orth, R. J. and K. A. Moore. 1981. Submerged aquatic vegetation in the
Chesapeake Bay: past, present and future. P. 271-283. In: Proc.
46th North American Wildlife and Natural Resources Conf. Wildlife
Manage. Inst., Wash., D.C.
Orth, R. J. and K. A. Moore. 1982. The biology and propagation of Zost?ra
marina, eelgrass, in the Chesapeake Bay, Virginia. U.S. EPA. Final
Report Chesapeake Bay Program. Grant No. R805953. 187 pp.
Orth, R. J. and K. A. Moore. 1983. Chesapeake Bay: an unprecedented
decline in submerged aquatic vegetation. Sci. 222:51-53.
Orth, R. J. and K. A. Moore. 1984. Distribution and abundance of submerged
aquatic vegetation in Chesapeake Bay: an historical perspective. Est.
7 :531~540.
Orth, R. J., K. A. Moore and H. H. Gordon. 1979. Distribution and
abundance of submerged aquatic vegetation in the lower Chesapeake Bay,
Virginia. U.S. EPA. Final Report. Chesapeake Bay Program. EPA-
600 78-79-029/SAV1 .
Orth, R. J., K. A. Moore and J. van Montfrans. 1982. Submerged aquatic
vegetation: Distribution and abundance in the lower Chesapeake Bay and
the interactive effects of light, epiphytes and grazers. U.S. EPA.
Final Report. Chesapeake Bay Program. Grant No. X003246. 236 pp.
-80-
-------
Rybicki, N. B., V. Carter, R. T. Anderson and T. J. Trombley. 1985.
Hydrilla vertlcillata in the tidal Potomac River, Maryland, Virginia,
and the District of Columbia, 1983 and 1984. U.S. Geological Survey.
Open File Report 85~77. 28 pp.
Stevenson, J. C. and N. M. Confer. 1978. Summary of available information
on Chesapeake Bay submerged vegetation. U.S. Dept. of Interior, Fish
and Wildlife Service. FWS/OBS-78/66. 335 pp.
Thayer, G. W., D. A. Wolfe and R. B. Williams. 1975. The impact of man on
seagrass systems. Am. Sci. 63=288-296.
U.S.E.P.A. Chesapeake Bay Program Technical Studies. A Synthesis. 1982.
Final Report. Washington, D.C. 635 pp.
Ward, L. G., W. M. Kemp and W. R. Boynton. 1984. The influence of waves
and seagrass communities on suspended sediment dynamics in an estuarine
embayment. Mar. Geol. 59:85-103.
-81-
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APPENDIX A
1TECIES OF SUBMERGED AQUATIC PLANTS FOUND IN THE CHESAPEAKE BAY AND
TRIBUTARIES (MODIFIED FROM CARTER, ET AL. , 1985)
Family
Species
Common name
Characeae
(muskgrass)
Najadaceae
(pondweed)
Chara brauni i Cm.
Chara zeylanica Km. ex Wild
Nitella flexilis (L). Ag.
Potamogeton perfoliatus L.
Potamogeton pectinatus L.
Potamogeton cri spus L
Potamogeton pusillus L.
Ruppi a mari tima L.
Zanni chellia palustri s L.
Najas quadalupensis (Spreng.
Morong
NaJ as gracill ima Magnus
Naias minor All
Muskgrass
Redhead-grass
Sago pondweed
Curly pondweed
Slender pondweed
Widgeongrass
Horned pondweed
Southern naiad
Naiad
Hydrocharitaceae
(frogbit)
Ceratophyllaceae
(coontail
Haloragidaceae
(watermilfoil)
Pondedariceae
(pickerelweed)
Potamogetonaceae
Vailisneria americana Michx.
Elodea canadenis (Michx.)
Planch.
Egeria densa Planch.
Hydrilla verticillata (L.f.)
Caspary
Ceratophyllum demersum L.
Myriophyllum spicatum L.
Heteranthera dubia (Jacqin)
MacM.
Zostera marina (L.)
Wildcelery
Common elodea
Water-weed
Hydrilla
Coontail
Eurasian
watermilfoil
Water-stargrass
eelgrass
-82-
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APPENDIX B
TOPOGRAPHIC QUADRANGLES SHOWING THE DISTRIBUTION AND ABUNDANCE OF SAV (1
<10J; 2 = 10-40?; 3 = ^0-70$; 4 = 70-100$)
-83-
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UNTOD tTATO
KPANTMJfT Of THE IKTOKM
OCOLOOCAL MJMVEY
HAVRE DC aHACE QUADRANGLE
SUBMERGED AQUA
r
-84-
-------
\
SUBMERGED AQUATIC VEGETATION 1984
NORTH KA«T QUADKANOLK
•• -- ..,•;'/ ;"' "•""
V**-
El
>2
-85-
-------
SUBMERGED AQUATIC VEGETATION 13*4
\r/.~ • ' •-
, .. - ^ \ , ir.«d, M«>*W>
\i -i\>P^x ••vA-T """"' "
iA.cjL/^'T L "¥.-"
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<
^J.
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CIMCWOOOVtIO.
-86-
-------
SUBMERGED AORMTKWEGETATUIN 1984
SHEET 57«2 I NW
\
C2 •
,'- PROVING • .-,--"*
.-/•
FERRYMAN, MARYLAND
PERRYMAN MAffYLAMO
-87-
-------
•SHU,-
". J.
•>—-5 1-
T "It i '
SPESUDE.MO
C»«M I
•oum. wmuK>
-88-
-------
V OCPAITTMErrT Of
~
m ' *» UWTU VTA TV*
|F^" SUBMERGED AQJJAIK^fljETATIOM 1984
C OUADftAMOLE
.
WIHVTI «MlM
J /
V.
v
V
r v •
1 n •
\: .
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-89-
-------
SUBMERGED AQUATIC VEGETATION 1984'
•X UNTOO gTATEB
*<.. DtPAimiENT or THE [Kruno*
X OtOUXHCAL tUKVCY
OUNPOWOCD NECK OUAOKANQLI
> / *Sd«hH «, c-> d* If M LJll^JI irf-l
JV* 0*« H UKMt — UMft
• - — — —
coMtou* «ri>«i jo in
GUNPOWDER NECK.MD.
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-90-
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— SUBMERGED
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-91-
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MET 57« I X
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BETTERTON.MO.
I1'
v,i
Plfc
H^1
-92-
-------
v uHmc rr*T*
\ Off AirmEKT Of THC
"*- OCOUXMCAL MJRVIY
r. ^ •'<
UMTTO «TAT«
OAL£MA QUAORANGLE
SUBMERGED AQUATtCifijfTATION 1984
•" " " '^ ^^L^~'
\
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- \
-93-
-------
UNITED STATES
DEPAffTMtNT OF THE INTCR
GEOLOGICAL SURVEY
.SUBMERGED
SWAN POIWT QUADBANOLt
• J HIHU^t KM* (TOPOOWAMCI
HAY
-94-
-------
rcVEGEIAIION 19M.
'Trr—~^'-*r ' s-x.'~ JRy,
v \ j'•>•'• *• .•''••. >^~m
^ '/ . • /*= ^^•L-,* , : . 7-A" '/>^i,
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• '^l ' / ' • - / x /' .
-95-
-------
s.\ UNrrro mm
V* OePAKTMEWT Of THE 1KTEWO*
OCOLQOICAL ftuirvrr
-96-
-------
-97-
-------
UHITED STATES
DEPA»Tm.NT OF THE
GEOLOGICAL SU»
.SaBMERGEffifiltWflC VEGETATIONJ984 :• —:
-98-
-------
Vv UNTOD «T*TE»
<» DEPARTMENT or rue n-n-unon
N OCOLOOICAL tunver
QUCCN8TOWN OUADItANOLZ
. SUBMEBGEaAQUAHC.VEGnATIOfJ1984
-99-
-------
\
SUBMERGED AQUATIC VEGETATION 1984
ALUUNOHIA OUAOHANOLI
*MOMU - OTTMCT or COUlMRU-ttMrWAIW
» WNUTI
/
/ Av^v-^sr '— --_-r- «SJ.T:- ^, *s. v / LA. =i
AfSf?pS^pSlS
-100-
-------
-101-
-------
UNrTtO STATES
DEPARTMENT or THE INTERIOR
CCOLOOlCAL SURVEY
ST MICHAELS QUADRANGLE
SUBMERGED AQUAHC VEGETATION 198A.
_102-
-------
KLVOIII OUADKANOU
T \fi \ / '5» ' \ ,'
^ '•••*^ ' "^ I"
V^--
-103-
-------
MOUKT VUmON OUAOKANOLI
-104-
-------
T1LOHMAN QUADRANGLE
\
TII
-105-
-------
LIMITED STATES
DCP»BTWEMT OF THE INTERIOR
GEOLOGICAL SURVEY
UNfTED STATES
OXFORD QUADRANGLE
< -.- ^ • .
»• - \ ^ V"' ' - - «i.
- •• -•
- *-' 1 \ \\
' ^ 1'14-
'"-""/x- '>-•/
V
\
-106-
-------
-107-
-------
SHARPS ISLAND QUADRANGLE
SUBMERGED /*QUAI|C VEGETATUIH 1984
\ -1
\ >
SAV PRESENT iN THIS AREA BU T N§T DEFECTED ON
ROVIDEO 8T
ENTAL LA80RATONIES
\
-108-
-------
\
MARYLAND
"*r :
('•
$UBMEDGED AQUAUC VEGETATION 19EL1
CHURCH CREEK QUADRANGLE
7
-------
-110-
-------
SUBMERGED AQUATIC VEGETATION 1984
IAWCMOY OUAOKANOLC *f
WIT UJtlfl fTOHOOfli^MIO >"
'%S&f . < - -
S i v -*
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H2
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-111-
-------
SUBMERGED AQUATIC VEGETATION 1884
MATtflA* POIHT OUADHANOLI
•Ill-
-------
' t / I *i *•» \ /"
- /l _\ -^^-^ ///,
v<$^ /
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-113-
-------
\
\
SUBKEBGED AQOAT1CJ/EGETAT1QN
covi fonrr OUAMANOLC
-114-
-------
SUBMERGED AQUATIC VEGETATION 1984
-115-
-------
N UWTtD tTATtt
\ DCPAHTMEMT OT THE IKTE*1O>
*• OCOUXMCAL tURVIY
SUBMERGED AQUATIC VEGETATION. 1984
^X -.. /•-- X;^^
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-116-
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UNTtTB tTATO
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SUBMEBGED AQUATIC VEGETATION 1984
•~x.
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-117-
-------
-118-
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SUBMERGED AQUATIC VEGETATION 1984
*/••<.,
03
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COLONIAL BEACH NORTH MD - V
-119-
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SUBMERGED AQUATIC VEGETATIPN 19&4. ,
*.;-'' )so<-. /V. 'v
^ -";x /• • >, ^'
-120-
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UNITED 1TATU
-121-
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' ADRAMOLE /
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SUBMEBEQ AaU
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-122-
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•
-123-
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-•r
SUBHERGED
HAKRIS LOT NO 3
NO 7
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-124-
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UNITED «TATE»
iEKT or THE iMTtjno«
eOUXHCAL MJHVCY
RKHLANO POtKT OUAMANOLX
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RICHLANO POINT,MO.
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