-------
Regional SAV Study Area Findings
Total Suspended Solids, Chlorophyll a,
and Light Attenuation: Choptank River
Light
Attenuation
Coefficient
(m-i)
5
0 o
Figure V-90. Three-dimensional comparisons of May-October median light attenuation coefficient, total suspended solids, and chlorophyll
a concentrations at the Choptank River stations from 1986-1989. Stations and years are plotted separately with SAV status indicated. Plus
= persistent SAV; flag = fluctuating SAV; circle = SAV absent.
Dissolved Inorganic Nitrogen, Dissolved Inorganic Phosphorus,
and Light Attenuation: Choptank River
Light
Attenuation
Coefficient
(m-1)
5
Figure V-91. Three-dimensional comparisons of May-October median light attenuation coefficient, dissolved inorganic nitrogen, and
dissolved inorganic phosphorus concentrations at the Choptank River stations from 1986-1989. Stations and years are plotted separately
with SAV status indicated. Plus = persistent SAV; flag = fluctuating SAV; circle = SAV absent.
91
CSC.SAV.12/92
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SAV Technical Synthesis
Growth Experiments
Macrophyte growth was studied in situ from April 1985
to July 1986, using a modified leaf marking technique
(Sand-Jensen 1975). Whole turfs of Z. marina (including
roots, rhizomes, and undisturbed sediments to a depth of
20 cm) were obtained from a stable grass bed at Guinea
Marsh, placed in polyethylene boxes (40 x 60 x 20 cm),
and submerged at the upri ver Gloucester Point and Claybank
sites. After a two-week acclimation period, three 15 cm
diameter quadrats were randomly located within each box.
Each shoot within each quadrat was tagged with a num-
bered, monel metal band placed around its base. The
youngest leaf was marked with a small notch and the leaf
lengths and widths were recorded. The boxes were re-
trieved at approximately weekly intervals and placed in a
seawater bath. The length and width of all leaves on tagged
shoots were recorded. The number of new leaves on each
shoot was recorded, any new shoots within the quadrats
were tagged, and the youngest leaf on all shoots was
marked. Thus, individual leaves could be uniquely iden-
tified and measured from formation
through loss. Dry weight and ash-free
weight were estimated from previously
derived linear regressions of leaf weight
on area. Growth rates and leaf losses
were calculated for each marking inter-
val. Using a two-way analysis of vari-
ance, the effect of site on various shoot
parameters was tested. Residual analy-
sis was used to check the aptness of all
models and Bonferroni multiple com-
parisons were used to locate site differ-
ences within sample intervals using a
family confidence coefficient of 0.95
(Neter and Wasserman 1974).
Boxes at the sites were disturbed peri-
odically, generally through the burrow-
ing of crabs or fish. Therefore, when
excavations occurred in a box at either
site, boxes at both sites were replaced
with others that had been acclimating at
the respective sites for identical periods
of time. Using information from the
marked plants, rhizome production rates
of the Gloucester Point and Claybank
transplants were determined between
initial transplanting in the fall of 1985
and the summer of 1986. Assuming that
average formation of the individual rhi-
zome segments occurred at the same
rate as that calculated for leaf produc-
92
tion (Sand-Jensen 1975; Jacobs 1979; Aioietal. 1981), the
age of each individual rhizome segment was determined
for each of the transplant samples obtained in March, May,
June, and July 1986. Rhizome production for the intervals
between each sampling was then calculated by summing
the biomass of rhizome segments produced during that
period.
Water Quality Monitoring
Triplicate subsurface (0.25 m) water column samples were
taken every two weeks at the shoal sampling sites along
the York River. Long-term data are available for the
Guinea Marsh, Gloucester Point, Mumfort Island, and
Claybank sites. The Aliens Island station was dropped in
September 1985, as its water quality parameters were
similar to Guinea Marsh and Gloucester Point (both char-
acterized by suitable SAV conditions). The Yorktown and
Catlett Island stations were added in December 1987 and
York River SAV Habitat Monitoring Stations
Guinea
Marsh
Figure V-92. The seven water quality sampling sites located in the nearshore and potential
SAV habitats in the lower York River region.
-------
Regional SAV Study Area Findings
Table V-13. York River SAV Habitat Monitoring Stations.
STATION NAME
Guinea Marsh
Aliens Island
Gloucester Point
Yorktown
Mumfort Island
Catlett Island
Claybank
LATITUDE
37°15'04"
37°15'11"
37°14'47"
37°14'25"
37°15'41"
37°18'55"
37°20'53"
LONGITUDE
76°22'59"
76°25'34"
76°30'09"
76°30'45"
76°30'42"
76°34'05"
76°36'33"
October 1985, respectively, to provide a better measure of
the variability associated with the transition from accept-
able to unacceptable water quality.
Water quality samples were collected sequentially on the
same day, beginning with the most downriver, and stored
on ice in the dark for up to four hours. Nitrite, nitrate, and
ammonium were determined spectrophotometrically fol-
lowing the methods of Parsons et al. (1984); inorganic
phosphorus was determined using EPA (1979) methods.
Suspended matter was collected onprecombusted, Gelman
Type A/E glass fiber filters, dried at 55 °C, and ashed at
550 °C for 5 hours. Chlorophyll a was collected on
Whatman GF/F glass fiber filters, extracted in a solution
of acetone, dimethyl sulfoxide (DMSO) and 1% diethylamine
(DBA) (45:45:10) following the methods of Shoaf and
Lium (1976) as modified by Hay ward and Webb (unpub-
lished), and determined fluorometrically. Chlorophyll a
concentrations were uncorrected for phaeopigments. Sa-
linity was measured with a refractometer or conductivity
meter, and temperature was measured by bulb thermom-
eter or thermistor.
Diffuse downwelling attenuation of photosynthetically
active radiation (PAR) was determined through water
column profiles of photosynthetic photon flux density
(PPFD) with a LI-COR, LI-192 underwater cosine cor-
rected sensor. The data were collected concurrently with
the water samples. Additionally, underwater PPFD was
measured continuously from August 1986 to September
1987 at the Gloucester Point and Claybank stations using
arrays of two underwater sensors placed vertically at fixed
distances. The sensors were cleaned frequently, and the
measured PPFD was corrected for fouling by assuming a
linear rate of light reduction due to fouling between cleanings.
The biweekly samples of the water column parameters,
obtained during the period of August 1984 to October
1989, were compared using two-way analysis of variance
as the main effects were date and site. Bonferroni multiple
comparisons were used to test for site differences within
sample dates using a family confidence coefficient of 0.95
(Neter and Wasserman 1974).
Results
Transplant Experiments
There have been no successful long-term transplants of Z.
marina at the Mumfort Island station or upriver sites since
1979. In contrast, the transplants have always been
successful at the Gloucester Point station. Transplant
survival was reported for Z. marina, transplanted in the fall
of 1979, after one year at the Guinea Marsh, Aliens Island,
Gloucester Point, and Mumfort Island stations as 98%,
93%, 82%, and 11%, respectively (Orth and Moore 1982).
By the following spring, no shoots remained at Mumfort
Island. A similar lack of success occurred with transplant
attempts at sites upriver of the Gloucester Point station
between 1980 and 1984.
Survival of Z. marina, transplanted each fall from 1985 to
1987 at the Gloucester Point and Claybank sites, are
presented in Figures V-93 and V- 94. Again, as with earlier
attempts, plants transplanted at all the sites did well after
initial losses due to wave scouring or burrowing of fish and
crustaceans. Beginning in the late spring, however, trans-
93
CSC.SAV.12/92
-------
SAV Technical Synthesis
plants at the stations upriver of Mumfort Island died back
with no survival by mid-to-late summer. Although prob-
lems associated with high turbidity and other unfavorable
conditions resulted in irregular sampling of the transplants
during the summer period, the data suggest that the dieback
occurred earlier than the more upriver sites. Dead trans-
plants were characterized by masses of blackened rhi-
zomes with no above ground material. In some cases,
when transplants were observed immediately prior to
complete loss, remaining shoots consisted of only one or
two short leaves.
There have been some inter-annual differences observed
in the length of survival of transplants immediately up-
stream of the Gloucester Point station. Prior to 1984, there
was limited success in transplanting at the Mumfort Island
station with transplants dying out during the summer after
fall transplanting (Orthe/ al. 1979). During the 1987-1988
period, however, the transplants survived throughout the
summer and into the fall, but by the next summer they
disappeared. Although no quantitative data were available
for 1986-1987, some living shoots transplanted in the fall
of 1986 were observed in the fall of 1987.
In the beginning of 1986, Z. marina plants were trans-
planted at the Yorktown station. Survival at this site (which
is along the western shore just downriver from Mumfort
Island) has been comparable to Gloucester Point with
transplanted beds now established. Since 1986,/?. maritima
recruitment has also been observed.
These data suggest that the relatively short region of the
York River in the vicinity of Gloucester Point is a transition
zone between acceptable and unacceptable environmental
conditions for SAV growth. It is likely, therefore, that
differences in these environmental conditions are small
and that SAV is growing close to their limits of tolerance,
even where it continues to flourish. Very small decreases
Zostera marina Transplant Survival - Gloucester Point
100-
90-
80-
70-
60-
50-
4O-
3O-
20-
1O-
O
Dot Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oot Nov
Figure V-93. Zostera marina transplant survival at Gloucester Point.
Zostera marina Transplant Survival - Claybank
100 -,
90-
80-
•a 70~
'1 60-
€ 50-
30-
20-
10-
0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Figure V-94. Zostera marina transplant survival at Claybank.
94
CSOSAV.12&
-------
Regional SAV Study Area Findings
in environmental quality can potentially harm the vegeta-
tion. Conversely, small improvements in environmental
conditions may likely result in significant increases in SAV
populations.
Growth Experiments
A bimodal pattern of above ground growth was observed
at the Gloucester Point and Claybank sites, where highest
Z. marina growth rates occurred each spring and a second
period of increased growth occurred in the fall (Figure V-
95). Significant differences in growth rates between the
sites were observed only during the spring and fall periods
(p<0.05).
From November until March, production of below ground
rhizomes of transplants at the Gloucester Point and Clay-
bank sites was low and comparable (p<0.05). Maximum
production occurred at both sites between March and May.
Production was greatest, however, from March until July
(when the Claybank vegetation died back) at Gloucester
Point (p<0.05).
Determination of Seasons
Characterization of seasonal Z. marina growth was deter-
mined by relating plant growth to water temperature, thus
allowing relationships to be developed between plant re-
sponse and environmental conditions based upon seasonal
growth patterns. To accomplish this, the 0 °C-30 °C and
30 °C-0 °C periods in the annual temperature cycle were
treated independently. For each temperature period, unique
regressions were fit to both the increasing and decreasing
portions of the growth curve using log rate vs. inverse
temperature transformations. The two resultant equations
for each temperature period were solved for the maximum
growth rate and inflection temperature. The temperature
cutoffs (at which growth equals 50% of this maximum rate)
were determined as follows:
For the 0 °C-30 °C temperature period, the calculated
regression equations for the increasing and decreasing
portions of the growth curve were:
1) G=-0.95 + (16.88 • (1/T)) and
2) G=0.49 - (6.42 • (1/T))
where G is the log growth rate, and T is the water
temperature.
Therefore, solving simultaneously for G produces
3) 6.42 • G = (6.42 • (-0.95) + (6.42 • 16.88 • (1/T)) and
4) 16.88 • G = (16.88 • (0.49)) - (16.88 • 6.42 • (1/T))
and finally,
G = 0.09.
Substituting G = 0.09 in either (1) or (2) yields an inflection
temperature of:
T = 16.2 °C.
Substituting the value of -0.21 (which is the log of 1/2 the
maximum growth rate, G1/2max) in equations (1) and (2)
produces:
Tj=9.2°C and
T2=22.7°C
which are the temperature cutoffs between the high
growth and low growth seasons for this period.
In a similar manner for the 30 °C-0 °C temperature period,
the calculated regression equations for the increasing and
decreasing portions of the growth curve were:
5) G = 0.49 - (9.95 • (1/T)) and
6) G = -2.32 + (50.96 (1/T))
where G is the log growth rate, and T is the water
temperature.
Solving simultaneously for G produces:
7) 50.96 • G = 50.96 - 0.49 - (50.96 • 9.95 • (1/T)) and
8) 9.95 • G = 9.95 • (-2.32) + (9.95 • 50.96 • (1/T))
therefore,
G = 0.31
for the second temperature period.
Again, substituting the quantity G = 0.31 into either (5 )
or (6) yields an inflection temperature of:
T = 21.7 °C.
Growth patterns of Zostera marina
Miy Jul S«p Nov Jtn Mir M«y Jul Stp Nov
Figure V-95. Above ground shoot growth of Zostera marina for the
Gloucester Point and Claybank sites for 1985-1986 data.
95
csc.SAV.ia/9a
-------
SAV Technical Synthesis
Substituting the quantity -0.27 (which is the log of 1/2 the
maximum growth rate) for G into (5) and (6) produces the
seasonal temperature cutoffs for this second period of:
T3=25.0°C and
T4=13.2°C,
respectively.
In summary, the annual temperature cycle was divided into
four distinct, biologically determined seasons (Figure V-
96) that reflect the bimodal pattern of Z. marina growth
characteristic of the polyhaline region of the Bay. These
temperature-derived seasons are used to compare water
quality parameters for the individual stations.
Wnter Quality Parameters
Habitat requirements for SAV in the polyhaline region of
Chesapeake Bay were determined from combined growing
season medians observed at those stations characterized by
persistent stands of natural or transplanted vegetation in the
York River. These seasons were either the spring or fall
periods when significant differences in Z. marina growth
were observed among the stations (described above). Water
quality parameters selected for this model are those dem-
onstrated to have the potential to influence plant survival:
light attenuation coefficient, total suspended solids, chlo-
rophyll a, dissolved inorganic nitrogen, and dissolved
inorganic phosphorus.
Temperature
The subsurface (0.25 m) annual water temperature regime
for the lower York River was characterized by rapid warm-
ing during the April-June period and cooling off during the
October-December period as illustrated in Figure V-97.
Growing Season Based on Temperature
Winter
Spring
Summer
Figure V-96. Zostera marina based seasonal growth periods. The "winter"
ranges from 13°- 0°- 9 °C, the "spring" from 9°- 23 °C, the "summer" from
23° • 30° • 25 °C and the "fair from 25° -13 °C.
Water temperature maxima approached 30 °C, minima was
less than 5 °C with differences between stations not sig-
nificant (p<.05).
Salinity
Salinity decreased with distance upriver (Figure V-98).
Annual minimums were reported during the period of
December -April. Although values to 6 ppt were occasion-
ally recorded, levels at the most upstream station were
generally greater than 10 (ppt). Maximums at this site in
the August-October period regularly approached 20 ppt.
Therefore, the entirereach can be characterized as mesohaline
to polyhaline and generally suitable for only those two
species of SAV tolerant of relatively high salinity levels-
Z. marina and R. maritima.
Light Attenuation Coefficient
Light attenuation coefficient in the York River increases
with distance upriver (Figure V-99), paralleling patterns
observed for total suspended solids. Figure V-100 presents
the least squares regression of light attenuation on total
suspended solids. Although a large amount of variability
results in a coefficient of determination (r2) of only 0.56,
the relationship suggests that particulates are the main
factor affecting light attenuation in this region. Of this
particulate load, the inorganic particles (e.g., suspended
silts and clays) appear to be the principal component;
whereas phytoplankton or phytoplankton-derived material
in the water column probably play a smaller role in block-
ing sunlight from the SAV.
The percent of total light attenuation due to the chlorophyll
a determined phytoplankton and phytoplankton derived
components of the suspended load was estimated as:
((l-e-c'Chl)/(l-e-K<1))» 100
where,
C is .016 m2 • mg-1 Chi a (after Bannister, 1974);
Chi is mg Chi a • m"3; and,
Kd is total light attenuation • m'1.
The values were low at the Guinea Marsh and Claybank
sites (Figure V-101) (less than 20% for the 1985-1987
period) but increased substantially from 1988-1989. This
increase parallels the rise in chlorophyll a reported for the
nearshore stations. Since few differences were observed
among stations for seasonal means of chlorophyll a con-
centrations for the 1984-1987 period, phytoplankton most
likely was not the sole factor limiting SAV growth, but was
a significant, additional stress.
The highest seasonal levels of light attenuation observed
in this study at vegetated sites were 2.0 m'1. The combined
96
-------
Regional SAV Study Area Findings
growing season median light attenuation coefficient values
were <1.5 nr1 at vegetated sites (see Figures V-l 15 and V-
116).
Total Suspended Solids
Total suspended solids were markedly higher with distance
upriver (Figure V-102). As illustrated in the Claybank site,
concentrations were quite variable because the shallows
were strongly influenced by resuspension due to wind.
Seasonal means (plant-derived seasons) for total suspended
solids were compared for the vegetated Gloucester Point
station and the currently unvegetated Claybank station by
two-way ANOVA (Figure V-103). Means were used
because two-way ANOVA tests for differences among
means. Levels were generally significantly greater (p<0.05)
at the Claybank site each spring when compared to the
downriver Gloucester Point station. Total suspended solid
levels were generally highest during the spring period. The
suspended load was composed principally of inorganic
particles as the organic content was generally less than
30%. This percentage decreased with distance upriver,
suggesting that the riverine input was enriched with inor-
ganic silts and clays relative to the estuary.
The combined growing season median concentrations of
total suspended solids observed in the downriver sites
where SAV have maintained viable populations was ap-
proximately 15 mg/1 at the Gloucester Point site. Since
levels at the upriver Claybank site, where SAV currently
will not grow, are significantly higher (particularly during
the spring when differences in growth of transplants are
most marked), <15 mg/1 combined seasonal median con-
centration of total suspended solids was determined to be
an important threshold for the plants (see Figure V-l 15).
Chlorophyll a
When compared seasonally, there were few significant
differences in chlorophyll a concentrations between the
Claybank and Gloucester Point stations (p<0.05) (Figure
V-104). Marked increases in chlorophyll a levels were
observed in both stations beginning in the fall of 1987 when
levels rose from <10 |Jg/l to between 10-20 ug/1 (Figure V-
105).
Although chlorophyll a may be an imperfect measure of
true phytoplankton biomass, it is a widely measured pa-
rameter and as yet, there is no evidence of significant
phytoplankton populations such as found in Long Island
embayments (Cosper et al. 1987; Dennison et al. 1989),
which may bias its use as a measure of phytoplankton
biomass in the Chesapeake Bay region. Highest seasonal
levels observed in this study were 15 ug/1 at the downriver
vegetated sites. Combined growing season median con-
centrations of chlorophyll a at these same sites were <15
ug/1 (see Figure V-l 15).
Dissolved Inorganic Nitrogen
Increases in dissolved inorganic nitrogen levels to 0.35
mg/1 were observed annually in the lower York River
nearshore areas from October-February (Figure V-106).
With distance upriver, concentrations rose earlier and
maintained higher levels longer. Differences among sta-
tion seasonal means were apparent only during the fall and
winter as demonstratedfortheGloucesterPointand Claybank
sites (Figure V-107). Dissolved inorganic nitrogen species
consisted principally of ammonium and nitrite with lower
levels of nitrate.
Highest seasonal levels of dissolved inorganic nitrogen at
vegetated sites were observed to be approximately 0.28
mg'1 during the fall period. The combined growing season
median concentrations were <0.15 mg/1 (see Figure V-
116). Since little difference in SAV growth was observed
among sites during the winter, when dissolved inorganic
nitrogen levels could be higher than these concentrations,
the combined growing season median was chosen as the
dissolved inorganic nitrogen habitat requirement. It is
most likely that low water temperatures, as well as low light
levels, are limiting SAV growth in this region during the
winter. Both epiphytic algae and phytoplankton are also
limited by these two factors, allowing dissolved inorganic
nitrogen to reach high levels.
Dissolved Inorganic Phosphorus
Dissolved inorganic phosphorus levels demonstrated less
annual variability than nitrogen, with the highest levels
occurring in the late summer and fall (Figure V-108).
Comparison of seasonal means between Gloucester Point
and Claybank stations revealed significantly increasing
levels with distance upriver during most seasons (Figure
V-l09). Highest seasonal levels were approximately 0.03
mg/1 during the spring or fall at vegetated sites. The
combined growing season median concentrations were
<0.02 mg/1 at vegetated sites and therefore was chosen to
characterize the SAV habitat requirement for dissolved
inorganic phosphorus (see Figure V-l 16).
Nitrogen:Phosphorus Ratios
Atomic ratios of dissolved inorganic nitrogen to dissolved
inorganic phosphorus demonstrated seasonal variation which
was largely a function of seasonal nitrogen input (Figure
V-l 10). Generally the nitrogen:phosphorus ratios suggest
that nitrogen should be limiting for phytoplankton growth
during much of the year, except during the late fall and
97
CSC.SAV.12/92
-------
SAV Technical Synthesis
York River Nearshore 1984-1989
Water Temperature
Claybank
Catlett Island
28
24
20
16
Mumfort Island 12
Yorktown
Gloucester PL „
o
Aliens Island 4 $
Guinea Marsh
28
24
20 SAV Absent
(Above 12 km)
I
16 »
12 s Fluctuating SAV
(10-12 km)
Persistent SAV
(Up to 10 km)
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Rgure V-97. Water temperature (°C) in the York River displayed by river kilometer over time.
Claybank
Catlett Island
28
24
20
16 -
York River Nearshore 1984-1989
Salinity
Mumfort Island 12
Yorktown
Gloucester Pt
8 -
Aliens Island 4
Guinea Marsh „
SAV Absent
(Above 12 km)
12 s Fluctuating SAV
•| (10-12 km)
8
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Persistent SAV
(Up to 10 km)
Rgure V-98. Salinity (ppt) in the York River displayed by river kilometer over time.
98
CSC.SAV.12A2
-------
Regional SAV Study Area Findings
York River Nearshore 1984-1989
Light Attenuation
28
Claybank
Catlett Island
Mumfort Island 12
Yorktown
Gloucester Pt.
Aliens Island 4
Guinea Marsh .
SAV Absent
(Above 12 km)
12 fe Fluctuating SAV
i (10-12 km)
Persistent SAV
(Up to 10 km)
VI I I | \ 1 |
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Figure V-99. Light attenuation (rrr1) in the York River displayed by river kilometer over time.
York River Nearshore 1984-1989
Ail Stations
6-
O)
2-
1-
0
10 20 30 40 50 60 70
Total Suspended Solids (mg/l)
80
Figure V-100. Light attenuation as a function of total suspended solids for all York River stations, 1984-1989.
90
100 110
99
CSC.SAV.12/92
-------
SAV Technical Synthesis
York River Nearshore 1984-1989
Chlorophyll a
'/ --- I -V
ffvi/iVV/n \ } /lyr^l]
Claybank
CatleK Island
Mumfort Island 12
Yorktown
Gloucester Pt
Aliens Island 4
Guinea Marsh
w ^ I | I i i
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Figure V-105. Chlorophyll a (ug/l) in the York River displayed by river kilometer over time.
SAV Absent
(Above 12 km)
12 5 Fluctuating SAV
• (10 - 12 km)
Persistent SAV
(Up to 10 km)
Microcosm Experiments
To test the single and interactive effects of nitrogen-
phosphorus inputs and submarine photosynthetically ac-
tive radiation on SAV growth and epiphytic fouling, a
series of seasonal, four to six-week, microcosm experi-
ments were conducted utilizing Z. marina. High, medium,
and low light treatments were chosen to simulate turbidity
levels that: 1) exceeded normal light availability in the
York River (Kd=0.84 nr1); 2) were characteristic of where
stable Z, marina beds were found (Kd = 1.23 nr1); and,
3) were characteristic of areas where no SAV was present
(Kd = 2.32 m"1). The microcosms were flow-through
systems fed with York River water from the Gloucester
Point site. Nutrient treatments were ambient and enriched
with 10 ug-at/1 inorganic nitrogen and 1 ug-at/1 inorganic
phosphorus. Temperature and salinity varied with source
water, and invertebrate grazers (Diastoma varium) were
at densities of 5000 organisms per square meter.
Nutrients had no measurable effect on microepiphyte ac-
cumulation when expressed on a whole shoot gram-spe-
cific basis for the three seasonal experiments (Figure
V-lll). Plant response to nutrient enrichment likewise
demonstrated no effect during the fall and spring. Gram-
specific production, however, was reduced during the
summer under enriched conditions (Figure V-l 12). These
seasonal differences may have been related to increased
macrophyte sensitivity created by higher water tempera-
tures. As respiratory demands increase with temperature,
the inhibitory effects of epiphytes on net plant growth
should increase. Macrophytes demonstrated marked re-
ductions in growth with decreasing levels of irradiance
during all seasons (Figure V-l 13). Plant growth was
reduced at both medium and low light treatments during
the fall (when solar irradiance was lowest). During spring
and summer, plant growth was reduced only at the lowest
light levels. Grazers maintained consistent enrichment
effects at all the light levels since there were no interactive
effects of light and nutrients. Epiphytic growth also dem-
onstrated marked light limitation, particularly at levels
characteristic of upriver, denuded sites (Figure V-l 14).
In a companion study, Neckles (1990) found comparable
results when testing the effects of nutrient enrichment and
epiphytic grazers on Z. marina growth. She concluded that
nutrient enrichment and epiphytic grazer activity interact
to regulate epiphyte loadings on the macrophytes, with
strong indirect effects on macrophyte production and sur-
vival. At levels of moderate nutrient enrichment (such as
that observed in the Claybank region), grazer activity
should negate the effects of enrichment on epiphyte load-
ings. Enrichment alone, therefore, should not limit sur-
vival, although it may depress annual macrophyte standing
stocks. Enrichment may increase the plants' sensitivity to
other potentially limiting factors, such as reduced levels of
irradiance.
102
CSC.SAV.1ZW
-------
Regional SAV Study Area Findings
York River Nearshore 1984-1989
Dissolved Inorganic Nitrogen
Claybank
Catlett Island
28
24
20
16
Mumfort Island 12
Yorktown
Gloucester PL „
o
Aliens Island 4
Guinea Marsh „
28
24
20
d 16
SAV Absent
(Above 12 km)
12 & Fluctuating SAV
H (10-12 km)
8
Persistent SAV
4 (Up to 10 km)
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Figure V-106. Dissolved inorganic nitrogen (mg/l) in the York River displayed by river kilometer over time.
Seasonal Dissolved Inorganic Nitrogen — York River
0.4.
0.3-
•1 0.2-
«
O
Gloucester Pt.
Clay Bank
m in in m co co co
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o>
oo
oo
•s E.
co
g i2
CO
1 I 2
^ I
CO
oo oo Oi o»
oo oo oo oo
O)
oo
CD
fl2l¥|2i€t
& i 5 ft E :& fr E
-
CO
CO
CO
Figure V-107. Seasonal dissolved inorganic nitrogen in the York River at Gloucester Point and Claybank. Asterisks show significant differences
(p<0.05).
103
CSC.SAV.12/92
-------
Regional SAV Study Area Findings
Claybank
Callett Island
Mumfort Island 12
Yorktown
Gloucester PL
Aliens Island 4
Guinea Marsh „
York River Nearshore 1984-1989
Dissolved Inorganic Phosphorus
SAV Absent
(Above 20 Km)
Fluctuating
SAV
(10-12 Km)
Persistent
SAV
(Up to 10 Km)
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Figure V-108. Dissolved inorganic phosphorus in the York River displayed by river kilometer over time.
Seasonal Dissolved Inorganic Phosphorus
- York River
I
M
a.
t
i
a
0.06
0.04-
0.02-
Gloucester Pt.
Claybank
if} L£"5 Lfy CO fQ ff>
CO GO OO GO GO GO
S* <5 =5§ o5 c1 o
•E e u- c •= s
r-> «—; s^ ^2_ cz
co § ^ co i
co co
CD J--
OO CO
f~- £S
GO °O
CO
OO OO
OO OO
co
OO O>
OO CO
O5
SO
Q-
(S)
CO
Figure V-109. Seasonal dissolved inorganic phosphorus means in the York River at Gloucester Point and Claybank. Asterisks show significant
differences (p<0.05).
104
CSCIRU1/92
-------
Regional SAV Study Area Findings
York River Nearshore 1984-1989
Dissolved Inorganic Phosphorus:Dissolved Inorganic Nitrogen
Claybank
Catlett Island
Mumfort Island 12
Yorktown
Gloucester Pt.
Aliens Island 4
Guinea Marsh _
28
24
on SAV Absent
(Above 12 km)
»
16 I
12 s Fluctuating SAV
i! (10-12 km)
Persistent SAV
(Up to 10 km)
Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec
1984 1985 1986 1987 1988 1989
Figure V-110. Dissolved inorganic phosphorus/dissolved inorganic nitrogen ratios in the York River displayed by river kilometer over time.
York River Microcosm Experiment
Microepiphyte Accumulation
2.5-
Ambient
Enriched
Summer 1988
Fall 1988
Spring 1989
Figure V-111. Microcosm microepiphyte responses to enrichment treatments. Different lowercase letters denote significant differences between treatments
at p <0.05.
105
CSC.SAV.12/92
-------
SAV Technical Synthesis
Table V-14. SAV Habitat Requirements for polyhaline habits in the York River applied as combined growing season medians.
Parameter Habitat Requirement
Light Attenuation
Total Suspended Solids
Chlorophyll a
Dissolved Inorganic Nitrogen
Dissolved Inorganic Phosphorus
<1.5 nr1
<15 mg/1
<15ug/l
<0.15 mg/1
<0.02 mg/1
Summary and Conclusions
These studies and experiments suggest that light availabil-
ity is the principal mechanism controlling plant survival in
polyhaline regions of the Bay. However, a variety of
factors including seasonal solar irradiance, temperature,
plant-sediment interactions, water column light attenua-
tion, nutrient enrichment, and epiphytic grazer activity
form a complex web of conditions that constrain produc-
tivity and ultimately survival. Attempts to characterize
suitable habitat should not focus on a single limiting factor
but on the range of variables influencing net growth.
The habitat requirements of SAV in the polyhaline regions
of the Bay are presented in Table V-14. Three-dimen-
sional comparisons of total suspended solids, chlorophyll
a, and light attenuation coefficient (Figure V-115) and
dissolved inorganic nitrogen, dissolved inorganic phos-
phorus, and light attenuation coefficient (Figure V-116)
illustrate both the basis for the polyhaline SAV habitat
requirements and the interrelationships between these
parameters. It is predicted, therefore, that Z. marina
dominated beds in these areas will survive at sites where
York River Microcosm Experiment
Plant Growth Nutrient Enrichment
Summer 1988
Fall 1388
Spring 1989
FigureV-112. Microcosm macrophyte responses to enrichmenttreatments.
Dilfefenttowercaselettersdenotesignificantdifferences between treatments
at p <0.05.
106
CSOSAV.Il'W
levels of the water quality variables are at or below the
values in Table V-14. Given the complex interaction of
potentially important factors, goals to improve water qual-
ity should focus on all factors rather than any single factor.
York River Microcosm Experiment
Plant Growth/Light Levels
40.
35-=
30J
15-i
10-;
5-=
a a
I
Summer 1988
Fall 1988
Spring 1989
FigureV-113. Microcosm macrophyte responsestolightreductiontreatments.
Different lowercase letters denote significant differences between treatments
at p <0.05.
York River Microcosm Experiment
Epiphyte Growth
Summer 1988
Fall 1988
Spring 1989
Figure V-114. Microcosm microepiphyte responses to light reduction
treatments. Different lowercase letters denote significant differences between
treatments at pz<0.05.
-------
Regional SAV Study Area Findings
Light
Attenuation
Coefficient
(m-i)
5
Total Suspended Solids, Chlorophyll a,
and Light Attenuation: York River
Figure V-115. Three-dimensional comparisons of combined March - May and September - November median light attenuation coefficient,
total suspended solids, and chlorophyll a concentrations at the York River stations from 1986-1989. Stations and years are plotted separately
with SAV status indicated. Plus = persistent SAV; flag = fluctuating SAV; circle = absent SAV.
Dissolved Inorganic Nitrogen, Dissolved Inorganic Phosphorus,
and Light Attenuation: York River
Light
Attenuation
Coefficient
(m-i)
5
Figure V-116. Three-dimensional comparisons of combined March - May and September - November median light attenuation coefficient,
dissolved inorganic nitrogen, and dissolved inorganic phosphorus concentrations at the York River stations from 1986-1989. Stations and
years are plotted separately with SAV status indicated. Plus = persistent SAV; flag = fluctuating SAV; circle = absent SAV.
107
CSC.SAV.t2/92
-------
-------
Chapter VI
Chesapeake Bay SAV Restoration Targets
he Submerged Aquatic Vegetation (SAV) Policy
for the Chesapeake Bay and Tidal Tributaries
(Chesapeake Executive Council 1989) established
the goal to achieve a net gain in SAV distribution and
abundance by "setting of regional SAV restoration goals
considering historical distribution records and estimates of
potential habitat." The baywide and regional SAV distri-
bution, density, and species distribution/diversity targets,
presented here, are critical in assessing the success of
efforts to restore SAV in Chesapeake Bay.
Chesapeake Bay SAV Distribution
Restoration Targets
Distribution Target Development Approach
Chesapeake Bay SAV distribution restoration targets were
developed by: mapping potential SAV habitat on U.S.
Geological Survey (USGS) quadrangles; removing shal-
low water habitat areas where SAV were not expected to
revegetate; and, comparing these areas with historical
survey data and the most current distribution data (Figure
VI-1). Composite SAV maps were plotted by USGS
quadrangles from all available computerized digital SAV
bed data from Chesapeake Bay aerial surveys (Orth un-
published 1971, 1974, 1980, and 1981 data; Orth et al.
1979, 1985, 1986, 1987, 1989, 1991; Orth and Nowak
1990; Anderson and Macomber 1980; Maryland Depart-
ment of Natural Resources unpublished 1979 data). The
1 and 2 m depth contours at mean low water (MLW) were
digitized from National Oceanic Atmospheric Adminis-
tration (NOAA) bathymetry maps. Because the NOAA
bathymetry maps are relatively inaccurate in small tidal
creeks and rivers where depth contours were generally not
present, an overestimate of an area within a certain depth
contour can occur. These maps were overlaid at the
1:24,000 scale to produce composite maps of known and
documented SAV distribution over time since the early
1970s, with the outline of potential SAV habitat initially
defined by the 1 and 2 m depth contours. All digital data
(stored on the Chesapeake Bay Program's ARC/INFO
Geographic Information System) was digitized and docu-
mented following the quality assurance/quality control
guidelines of Orth and Nowak (1990).
Potential habitat was initially defined as all shoal areas of
Chesapeake Bay and tributaries less than 2 m. Although
historical SAV in Chesapeake Bay probably grew to 3 m
or more, the 2 m depth contour was chosen because it was
the best compromise of the anticipated maximum depth
penetration of most SAV species when both the 1 and 2
m habitat requirements for one and two meter restoration
are achieved baywide. For several SAV species (notably
Myriophyllum spicatum and Hydrilla verticillata) maxi-
mum depth penetration might be greater than 2 m, but it
was felt that this would be an exception. The 1 m depth
contour was selected because this is the limit of SAV depth
penetration given achievement of the SAV habitat require-
ments for 1 m restoration.
Areas that were highly unlikely to support SAV were
annotated on the composite maps by the principal inves-
tigators (Table VI-1). Criteria for excluding certain areas
from the maps was based primarily on the principal inves-
tigators' application of information from early historical
surveys, documented personal observations, and anecdotal
information on the absence of SAV from a particular area
since the last century. In addition, a detailed examination
of data from the last two decades of SAV monitoring using
aerial photography, ground survey documentation from
the last 20 years, and historical photography was also
included. Specific criteria using substrate and exposure
were not used because of the complexities in SAV growth
patterns in the Bay and tributaries that make the use of such
criteria exceedingly difficult.
There was limited information that could be used to delin-
eate and designate shallow water areas (less than 2 m
MLW) as highly unlikely to support future SAV growth.
The composite SAV maps included distribution data only
covering the time period after significant SAV declines
started in the 1960s and early 1970s. There was no baywide
mapping of SAV until 1978, with a 5-year break before the
next baywide survey in 1984. Historical aerial photogra-
phy for shallow water areas was not available for many
years and not on a baywide basis for any single year. The
utility of the available historical photography was question-
able at best since the photographs were not collected under
109
CSC.SAV.12/92
-------
SAV Technical Synthesis
Process For Setting Chesapeake Bay
SAV Distribution Restoration Targets
SAV beds
Adjacent land
1. 1971, 1974, 1978,
1979, 1980, 1981, 1984-
1987, 1989, and 1990
regional and baywide SAV
aerial survey digital data
overlaid to develop
composite maps of SAV
distribution plotted by
USGS quadrangle.
2. The one and two meter
depth contours digitized
from NOAA bathymetry
maps and plotted by USGS
quadrangle.
3. SAV composite map and
the one and two meter depth
contours overlaid.
5. Areas
delineated as
unlikely to
support SAV
deleted from
the map.
Area unlikely to
support SAV
Chesapeake Bay SAV Distribution
Restoration Targets
Figure Vl-1. Process for setting Chesapeake Bay SAV distribution restoration targets.
4. Composite map
reviewed by SAV principal
investigators; areas unlikely
to support SAV delineated
and annotated.
6. Three-tiered SAV
distribution restoration targets
delineated and maps of SAV
distribution restoration targets
by USGS quadrangle
produced along with tables of
acreages by USGS
quadrangle, Chesapeake Bay
SAV Aerial Survey Segment,
and Chesapeake Bay
Program segment.
110
CSOSAV.1W2
-------
Chesapeake Bay SAV Restoration Targets
Table VI-1. Chesapeake Bay principal investigators responsible for reviewing the SAV composite maps to delineate the SAV distribution
restoration targets.
Principal
Investigator
Affiliation
Shoreline regions of the
Chesapeake Bay reviewed
Robert Orth Virginia Institute of Marine
Science
Lorie Staver University of Maryland-Horn
Point Environmental Laboratory
Stan Kollar Harford Community College
Virginia western shore from Cape Charles to Point
Lookout (including the James, Rappahannock, and
York rivers); upper Maryland western shore from
North Beach to Spesutie Island; upper Maryland
Eastern Shore from Betterton south to Eastern Neck
Island; lower Maryland and the entire Virginia
Eastern Shore from Taylors Island to Cape Henry.
Maryland western shore from Point Lookout (at the
mouth of the Potomac River) north to North Beach
(including the Patuxent River); Maryland Eastern
Shore from Taylors Island to Eastern Neck Island
(including the Choptank River, Eastern Bay, and
Chester River).
Spesutie Island north to the Susquehanna Flats and
down to Betterton at the mouth of the Sassafras
River (including the Northeast and Elk rivers).
Virginia Carter U.S. Geological Survey-Reston Potomac River and its tributaries.
conditions required for photo-interpretation and mapping
of SAV.
All available information was utilized during the process
of defining the distribution restoration targets. Habitat
areas exposed to high wave energy and which have under-
gone physical modifications to the point they could not
support SAV growth were excluded based on a review of
the information. The absence of documentation on the
historical presence of SAV in a certain region of a tributary,
embayment, or the mainstem was not used as a reason to
delineate and exclude the shallow water habitats in these
regions as unlikely to support future SAV growth. This
type of information was used in establishing the tiered
approach to target setting. For example, some areas that
have not supported SAV in the recent past (such as the tidal
fresh and oligohaline areas of the James, York, and Rap-
pahannock) were included in the distribution restoration
targets. This distinction was based on the following as-
sumption: since the upper Potomac River near Washing-
ton, DC, supported dense stands of SAV in the early 1900s
(Gumming et al. 1916), there should be no reason to assume
that SAV was not present in similar areas in the tidal fresh
and oligohaline reaches of other river systems in Chesa-
peake Bay. The anecdotal evidence from disparate regions
of the B ay as well as aerial photographic evidence for some
areas in the 1930s indicates the major areas where SAV
grew in the early part of the 20th century. In addition, many
small tidal creeks in tidal fresh and oligohaline areas
throughout the Bay today contain small pockets of a variety
of SAV species. It is assumed that these are the last
remnants of what were once large expansive stands in
earlier periods in the upper sections of these tributaries.
The seed and pollen record (Brush and Hilgartner 1989)
support this line of evidence that SAV was once signifi-
cantly more abundant than it is today.
The areas annotated as highly unlikely to support SAV
were digitized and deleted from the ARC/INFO files of
potential SAV habitat delineated by the 2 m depth contour.
A second level of habitat restriction was considered in
those areas where SAV was presently found or had the
potential to grow in the 2 m contour. This habitat restric-
tion was considered in areas where wave exposure is highly
likely to prevent SAV from growing down 2 m in depth
but would be dampened enough to allow SAV to grow
closer inshore (less than 1 m). Assessment of areas that
would fall into this category was based on the same criteria
used to generate the composite maps for the 2 m restricted
areas.
SAV Distribution Restoration Targets
To provide stepwise measures of progress, a tiered set of
SAV distribution restoration targets have been established
111
csc.Sfty.ta92
-------
SAV Technical Synthes
Table VI-2. Chesapeake Bay Program segment descriptions.
Segment Description
Segment
Description
CB1 Northern Chesapeake Bay
CB2 Upper Chesapeake Bay
CB3 Upper Central Chesapeake Bay
CB4 Middle Central Chesapeake Bay
CB5 Lower Chesapeake Bay
CB6 Western Lower Chesapeake Bay
CB7 Eastern Lower Chesapeake Bay
CB8 Mouth of the Chesapeake Bay
\VT1 Bush River
WT2 Gunpowder River
\VT3 Middle River
WT4 Back River
WT5 Patapsco River
WT6 Magothy River
WT7 Severn River
WT8 South/Rhode/West Rivers
TF1 Upper Patuxent River
RET1 Middle Patuxent River
LEI Lower Patuxent River
TF2 Upper Potomac River
RET2 Middle Potomac River
LE2 Lower Potomac River
TF3 Upper Rappahannock River
RETS Middle Rappahannock River
LE3 Lower Rappahannock River
TF4 Upper York River
RET4 Middle York River
LE4 Lower York River
WE4 Mobjack Bay
TF5 Upper James River
RETS Middle James River
LE5 Lower James River
ET1 Northeast River
ET2 Elk/Bohemia Rivers
ET3 Sassafras River
ET4 Chester River
ET5 Choptank River
ET6 Nanticoke River
ET7 Wicomico River
ET8 Manokin River
ET9 Big Annemessex River
ET10 Pocomoke River
EE1 Eastern Bay
EE2 Lower Choptank River
EE3 Tangier Sound
for Chesapeake Bay. Each target represents expansions in
SAV distribution that are anticipated in response to im-
provements in water quality. These water quality improve-
ments will be measured as achievement of the SAV habitat
requirements for one and two meter restoration. The SAV
distribution restoration targets are presented by Chesa-
peake Bay Program Segment (Tables VI-2 and VI-3 and
Figure VI-2), Chesapeake Bay SAV Aerial Survey Seg-
ment (AppendixD), and USGS quadrangle (Appendix D).
Baywide maps of the Tier I and III SAV distribution
restoration targets are presented in Figures VI-3 and VI-4.
Tier I Target: Restoration of SAV to areas currently or
previously inhabitedby SAV as mapped through regional
and baywide aerial surveys from 1971 through 1990.
Achievement of this SAV distribution restoration target
depends on achievement of the SAV habitat requirements
for one meter restoration (Table IV-1) in areas delineated
as current or previous SAV habitat based on all aerial
surveys conducted from 1971 through 1990, and on the
presence of sufficient propagules and other environmental
factors that limit growth (e.g., salinity, temperature, sedi-
ment substrate, herbicides) remaining within the tolerance
limits of the SAV species.
Tier H Target: Restoration of SAV to all shallow water
areas delineated as existing or potential SAV habitat
down to the one meter depth contour.
Achievement of this SAV distribution target also depends
on achievement of the SAV habitat requirements for one
meter restoration (Table IV-1) and aims for SAV growth
down to one meter in depth. Tier II includes all areas in
Tier I as well as all areas delineated within the one meter
depth contour in the Chesapeake Bay and its tributaries.
Tier II excludes a number of areas that are considered
highly unlikely to support SAV. These areas occur in
regions where the physical exposure to intense wave and
current energy would prevent the establishment of any
112
CSOSAV.1292
-------
Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Program Segments
CB1
WT1
ET1
WT2
RET2
TF5
CBS
LE5
Figure VI-2. Chesapeake Bay Program segmentation scheme used to report the SAV distribution restoration targets.
113
CSC.SAV.12/92
-------
SAV Technical Synthesis
Table Vl-3.
Chesapeake Bay SAV Distribution Restoration Tier I and Tier III Targets by Chesapeake Bay Program Segment.
Tier I 1990 SAV Distribution as Tier in 1990 SAV Distribution as
1990 SAV SAV Restoration
CBP
Segment
CB1
CB2
CBS
CB4
CBS
CB6
CB7
CBS
WT1
WT2
WT3
WT4
WT5
WT6
WT7
WT8
TF1
RET1
LEI
TF2
RET2
LE2
TF3
RETS
LE3
TF4
RET4
LE4
WE4
TF5
RETS
LE5
ET1
ET2
ET3
ET4
ET5
ET6
ET7
ET8
ET9
ET10
EE1
EE2
EE3
TOTALS
114
CSC.SAV.12/S2
Distribution
(Hectares)
1780
19
36
5
4981
511
3112
29
0
87
3
0
0
0
0
0
0
0
0
1642
1367
51
0
0
401
0
0
79
4192
0
0
3
0
364
39
33
0
0
0
103
128
0
391
188
4849
24393
Target
(Hectares)
3101
139
817
103
6309
783
4624
86
24
353
349
0
53
240
189
78
6
16
132
3098
1847
282
0
0
1714
0
0
309
5902
0
13
16
7
467
167
1506
191
0
0
271
363
0
2474
3646
6350
46025
a Percentage of the
Tier I SAV
Restoration Target
57%
14%
4%
5%
79%
65%
67%
34%
0%
25%
<1%
0%
0%
0%
0%
0%
0%
0%
0%
53%
74%
18%
0%
-
23%
-
-
26%
71%
-
0%
19%
0%
78%
24%
2%
0%
-
-
38%
35%
-
16%
5%
76%
53%
SAV Restoration
Target
(Hectares)
6975
3086
3426
3496
15083
2923
11803
1928
1836
3056
839
1061
1452
838
883
1970
890
959
2653
8304
7443
18012
3293
5928
9342
1614
2915
4822
12529
5780
4987
13841
1207
2967
1515
5812
3009
4082
2648
3763
2044
495
8815
11648
35686
247658
a Percentage of the
Tier ffl SAV
Restoration Target
26%
<1%
1%
<1%
33%
17%
26%
2%
0%
3%
<1%
0%
0%
0%
0%
0%
0%
0%
0%
20%
18%
<1%
0%
0%
4%
0%
0%
2%
33%
0%
0%
<1%
0%
12%
3%
<1%
0%
0%
0%
3%
6%
0%
4%
2%
14%
10%
-------
Chesapeake Bay SAV Restoration Targets
-------
-------
Chesapeake Bay SAV Restoration Targets
SAV propagules. These areas are predominantly in the
mainstem of Chesapeake Bay (e.g., the shoreline between
the mouth of the Potomac and Patuxent rivers). Tier II also
excludes areas where extensive physical disruption of the
shoreline and nearshore habitat would prevent SAV from
reestablishing (e.g., certain areas in the Hampton Roads
and Baltimore Harbor regions). Achievement of this SAV
distribution restoration target will also depend on the
presence of sufficient propagules. In addition, other en-
vironmental factors limiting growth and reproduction (e.g.,
salinity, temperature, sediment substrate, and herbicides)
must be within the general tolerance limits of the SAV
species.
Tier HI Goal: Restoration of SAV to all shallow water
areas delineated as existing or potential SAV habitat
down to the two meter depth contour.
Achievement of this SAV distribution target depends on
achievement of the SAV habitat requirements for two
meter restoration for light penetration (Table IV-1) and
aims for SAV growth down to two meters in depth. Tier
III includes all areas in Tiers I and II as well as all areas
delineated within the two meter depth contour in Chesa-
peake Bay and its tributaries. Tier III excludes the same
areas as Tier II as well as some selected areas within the
one-two meter depth contour where primarily wave expo-
sure will limit SAV growth to the one meter depth contour.
Achievement of this SAV distribution restoration target
will also depend on the presence of sufficient propagules.
In addition, other environmental factors limiting growth
and reproduction (e.g., salinity, temperature, sediment
substrate, and herbicides) must be within the general tol-
erance limits of the SAV species.
A total of 46,025 hectares of SAV has been mapped as
comprising the Tier I target. The 1990 estimate of SAV
abundance indicates that the current levels of SAV are 53%
of Tier I. Areas with greater than 50% of the target are
CB1-57% (Northern Chesapeake Bay), CB5-79% (Lower
Chesapeake Bay), CB6-65% (Western Lower Chesapeake
Bay), CB7-67% (Eastern Lower Chesapeake Bay), TE2-53%
(Upper Potomac River), RET2-74% (Middle Potomac
River), ET2-78% (Elk/Bohemia rivers), WE4-71%
(MobjackBay), andEE3-76% (TangierSound). Although
the two upper Bay segments that include the Susquehanna
Flats region have high percentages, 95% of the vegetation
area is very sparse and has remained sparse during the
aerial surveys. These segments historically supported
some of the densest stands of SAV in the Bay. Today, the
large area of the Flats supports only sporadic patches of
one species (M. Spicatum); whereas in the past, dense,
continuous, multi-species beds were present (Bayley et al.
1978). Thus, the density and species diversity targets for
this region are below the expected targets. Surprisingly,
a large number of species are found in the many fringing
beds in this region but most are dominated by one or a few
species (Orth and Nowak 1990; Orth et al. 1991).
Interestingly, the rapid expansion of H. verticillata in the
upper Potomac River and the upper portion of the middle
Potomac River in the 1980s has contributed to the vegeta-
tion of a relatively large area of the potential habitat.
Although H. verticillata is the numerically dominant spe-
cies in the Potomac, many of the areas inshore of the
H. verticillata beds are vegetated with numerous other
SAV species (Orth and Nowak 1990; Orth et al. 1991).
Based on Tier I targets, SAV is doing best in the lower
mainstemBay segments (CBS, CB6, CB7, andEEl) where
water quality conditions are better than upper Bay or upper
tributary areas. In particular, SAV is notably absent, or in
very reduced abundance, in many of the upper western
shore tributaries (WTl-Bush River, WT2-Gunpowder
River, WT3-Middle River, and WT8-South/West/Rhodes
rivers), many of the eastern shore tributaries (ETl-North-
eastRiver, ET4-Chester River, ET5-Choptank River, ET6-
Nanticoke River, ET7-Wicomico River, and
ETIO-Pocomoke River), the Patuxent River (TF1, RET1,
and LEI), the lower Potomac River (LE2), the middle and
upper York River (RET4, TF4), and the James River (LE5,
RETS, and TF5). Of the five major western shore tribu-
taries, the James and Patuxent rivers have the least amount
of SAV.
Delineation of the Bay bottom for the Tier III target showed
247,659 hectares of potential habitat within the two meter
depth contour. The 1990 SAV distribution indicates that
the current levels are only 10% of the target for Tier III.
Areas with greater than 10% of the target are CBl-25%
(Northern Chesapeake Bay), CB5-33% (Lower Chesa-
peakeBay), CB6-18% (Western Lower Chesapeake Bay),
CB7-26% (Eastern Lower Chesapeake Bay), TF2-20%
(Upper Potomac River), RET2-18% (Middle Potomac
River), ET2-12% (Elk/Bohemia rivers), WE4-34%
(Mobjack Bay), and EE3-14% (Tangier Sound). As with
Tier I, the greatest proportion of Tier III target achievement
was in the lower Bay segments where water quality con-
ditions are better.
There are two additional considerations for the applica-
tion of the tiered distribution restoration targets.
First, the tiers, as presented, do not take into account the
density of SAV in a segment. For example, a large bed
117
CSC.SAV.12/92
-------
SAV Technical Synthesis
Table VI-4. Chesapeake Bay SAV Density
1990 SAV
CBP Distribution
Segment
CB1
CB2
CBS
CB4
CBS
CB6
CB7
CBS
WT1
WT2
WT3
WT4
WT5
WT6
WT7
WT8
TF1
RET!
LEI
TF2
RET2
LE2
TF3
RETS
LE3
TF4
RET4
LE4
WE4
TF5
RETS
LE5
ET1
ET2
ET3
ET4
ET5
ET6
ET7
ET8
ET9
ET10
EE1
EE2
EE3
TOTALS
118
CSOSAV.1M2
(Hectares)
1780
19
36
5
4981
511
3112
29
• 0
87
3
0
0
0
0
0
0
0
0
1642
1367
51
0
0
401
0
0
79
4192
0
0
3
0
364
39
33
0
0
0
103
128
0
391
188
4849
24393
Restoration Targets Status by Chesapeake Bay Program Segments.
1990 SAV Distribution
1990 SAV Distribution Tier I within 70-100% Density
(and%) within 70-100% SAV Restoration Category as Percentage
Density Category Target of Tier I SAV
(Hectares)
84
0
<1
0
1512
303
1412
<1
0
27
0
0
0
0
0
0
0
0
0
1187
824
5
0
0
50
0
0
60
2635
0
0
3
0
0
0
1
0
0
0
0
53
0
5
33
3047
11243
, (5%)
(0)%
(1%)
(0%)
(30%)
(59%)
(45%)
(1%)
(-)
(31%)
(0%)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(72%)
(60%)
(10%)
(-)
(-)
(13%)
(-)
(-)
(76%)
(63%)
(-)
(-)
(100%)
(-)
(0%)
(0%)
(3%)
(-)
(-)
(-)
(0%)
(41%)
(-)
(1%)
(18%)
(63%)
(46%)
(Hectares)
3101
139
817
103
6309
783
4624
86
24
353
349
0
53
240
189
78
6
16
132
3098
1847
282
0
0
1714
0
0
309
5902
0
13
16
7
467
167
1506
191
0
0
271
363
0
2474
3646
6350
46025
Restoration Target
3%
0%
1%
0%
24%
39%
31%
1%
0%
'8%
0%
0%
. 0%
0%
0%
0%
0%
0%
0%
38%
45%
2%
-
-
3%
, -
, ,
19%
45%
-
0%
19%
0%
0%
0%
1%
0%
0%
0%
0%
, 15%
0%
1%
1%
48%
. 24% . . . . .
-------
Chesapeake Bay SAV Restoration Targets
in tine Susqueharma Flats which has SAV but at a very low
density (<10 % or a density class of 1) (see Orth etal. 1991
for a description of density classes) would carry the same
weight as a very dense bed (>70 % coverage or a density
class of 4) (see density restoration section). Second, the
tiered approach does not incorporate aspects of species
diversity (see species restoration section). For example,
a part of a segment that historically contained two or more
species would be valued the same today if only one species
currently existed there. As progress toward SAV restora-
tion is reviewed, progress toward all three sets of restora-
tion targets for distribution, density, and species distribution/
diversity should be examined concurrently.
Chesapeake Bay SAV Density
Restoration Targets
For all habitat areas delineated within the SAV distribution
restoration targets, the SAV density restoration target is to
maximize the amount of SAV coverage present within the
70-100% density category of the crown density scale used
in the Chesapeake Bay SAV Aerial Survey (Orth et al.
1991). Table VI-4 presents a comparison of the 1990
baywide aerial survey depth with the Chesapeake Bay
SAV density restoration target.
The 1990 SAV distributional survey delineated 11,243
hectares of bottom that were classified as dense (70-100%
coverage based on Orth et al. 1991), or 46% of the total
SAV mapped for the Bay and tributaries in 1990. This
Table VI-5. Species of SAV found in Chesapeake Bay and its tidal tributaries.
Family
Characeae
Potamogetonaceae
Ruppiaceae
Zannichelliaceae
Najadaceae
Hydrocharitaceae
Species
Chora braunii Gm.
Cham zeylanica Klein ex Willd., em.
Nitellaflexilis (L). Ag., em
Potamogeton perfoliatus, L. var. bupleuroides
(Femald) Farwell
Potamogeton pectinatus L.
Potamogeton crispus L.
Potamogeton pusillus L.
Potamogeton amplifolius
Potamogeton diversifolius
Potamogeton epihydrus
Potamogeton gramineus
Potamogeton nodosus
Ruppia maritima L.
Zannichellia palustris L.
Najas guadalupensis (Sprengel) Magnus
Najas gracillima (A. Braun) Magnus
Najas minor Allioni
Najas muenscheri
Najas flexilis
Vallisneria americana Michaux
Elodea canadensis (Michaux)
Egeria densa Planchon
Hydrilla vertidllata (L.f.) Boyle
Common Name
Muskgrass
Redhead grass
Sago pondweed
Curly pondweed
Slender pondweed
Widgeongrass
Horned pondweed
Southern naiad
Naiad
Wild celery
Common elodea
Water-weed
Hydrilla
Pontedariaceae Heteranthera dubia (Jacquin) MacMillian Water stargrass
Ceratophyllaceae Ceratophyllum demersum L. Coontail
Trapaceae Trapa natans L. Water chestnut
Haloragaceae Myriophyllum spicatum L. Eruasian water milfoil
Zosteraceae Zostera marina L. Eelgrass
Classification and nomenclature derived from: Godfrey and Woolen, 1979,1981; Harvill et al. 1977,1981; Kartesz and Kartesz, 1980; Radford et al. 1968;
Wood and Imahori, 1965.
Sources: Brush 1987; Brush and Hilgartner 1989; Carter et al. 1985a; Davis 1985; Hurley 1990; Maryland DNR unpublished data; Orth and Nowak 1990;
Orth etal. 1979; Chesapeake Bay Program, unpublished data; Paschal et al. 1982; R. Younger Personal Communication; Rybicki etal. 1988,1987,1986;
Stevenson and Confer 1978.
119
CSC.SAV.1M2
-------
SAV Technical Synthesis
represents 24% of the SAV Density Restoration Target for
the SAV I SAV Distribution Restoration Target. Areas
with significant coverage in this density class are CB5-24%
(Lower Chesapeake Bay), CB6-39% (Western Lower
Chesapeake Bay), WE4-45% (Mobjack Bay), EE3-48%
(Tangier Sound), TF2-38% (Upper Potomac River), and
RET2-44% (Middle Potomac River). These data for the
density restoration targets contrast with the Tier I target
percentages since several of the segments, despite high
percentages towards achievement of Tier I, had sparse
coverage and thus much lower estimates for the density
restoration target-notably the upper Chesapeake Bay area
for the Susquehanna Hats and the Elk and Bohemia rivers.
All the segments with the highest percentages in the density
restoration targets were along both the eastern and western
shores of the lower Chesapeake Bay, reflecting the better
water quality in the mainstem of the Bay, and in the
Potomac River, where H. verticillata and other native
species have rapidly recolonized the shoals over the last
seven years.
Chesapeake Bay SAV Species
Distribution/Diversity Restoration
Targets
Species Distribution/Diversity Restoration
Targets Development Approach
Targets for Chesapeake Bay SAV species distribution/
diversity restoration were developed based on both present
and historical SAV distribution patterns. Species distribu-
tion information included in this analysis was synthesized
from surveys of present SAV distribution, surveys from
past pollen and seed records, and the literature (listed in
Appendix C) which is summarized below.
• SAV aerial survey database made by ground survey
andhabitatmonitoringprogramsconductedbyUSGS,
Harford Community College, Maryland's Charterboat
Captain survey, U.S. Fish and Wildlife Service Citizen
Hunt program, University of Maryland Horn Point
Environmental Laboratory (HPEL) surveys, and Vir-
ginia Institute of Marine Science (VIMS) ground
surveys (as reported in Orthef al. 1985,1986,1987,
1989, 1991; Orth and Nowak 1990).
• Maryland Department of Natural Resources SAV
Ground Survey of 644 stations including physical
characteristics of the water column, bed biomass,
and density.
• U.S. Geological Survey Potomac River Estuary
Program Data Reports.
• Pollen and seed record of the upper Bay including
the Choptank River and Furnace Bay (Davis 1985;
Brush 1987; Brush and Hilgartner 1989).
• The U.S. Fish and Wildlife Service summary of all
available SAV information from 1877 to 1978 de-
tailing findings from research, surveys, and histori-
cal trend analyses (Stevenson and Confer 1978).
A comprehensive, cumulative listing of all SAV species
by Chesapeake Bay segment, documented in the available
literature and in the Chesapeake Bay Program Computer
Center database, was then compiled and documented by
information source (Appendix C, Table C-1). SAV species
were recorded for each Chesapeake Bay Program segment
based on estimates from maps and site descriptions. Where
survey regions overlapped more than one segment, SAV
species were assigned to all affected segments.
The Chesapeake Bay species distribution/diversity targets
presented by Chesapeake B ay Program segment in Appen-
dix C (Table C-2) were developed based on information
compiled in Appendix C, Table C-l and the potential
species distribution maps for the most common Chesa-
peake Bay SAV species (Figures VI-5 through VI-16).
A total of 28 SAV species are presently found in the
Chesapeake Bay and tributaries (Table VI-5), including
three species of Characeae which are not true rooted
species. Twelve species are found most commonly; their
distributional limits ultimately determined by salinity.
Zostera marina is dominant in the more saline, lower
reaches of the Bay. Myriophyllum sp icatum, Potamogeton
pectinatus, Potamogeton perfoliatus, Zannichellia palus-
tris, Vallisneria americana, Elodea canadensis, Cerato-
phyllum demersum, H. verticillata, Najas guadalupensis,
and Heteranthera dubia are less tolerant of high salinities
and are found in the middle and upper reaches of the
Chesapeake Bay. Ruppia maritima is tolerant of a wide
range of salinities and is found from the Bay's mouth to the
Susquehanna Flats. The other species listed in Table VI-
5 are found only occasionally, and if present, occur prima-
rily in the middle and upper reaches of the Chesapeake Bay
and its tidal tributaries.
The SAV community associations of the Chesapeake Bay
are an important factor in setting SAV species distribution/
diversity restoration targets. These associations are based
on a variety of parameters to which members of a particular
community are equally tolerant. In an extensive survey of
120
CSCSAV.1M2
-------
Chesapeake Bay SAV Restoration Targets
SAV in the lower Chesapeake Bay, Orth et al. (1979)
distinguished three plant associations based on the co-
occurrence of species in particular habitats. These asso-
ciations are best explained by their location and salinity.
Z. marina and R. maritima compose the primary associa-
tion in the lower, higher salinity portions of the Chesapeake
Bay. M. spicatum, P. pectinatus, P. perfoliatus, Z. palustrls,
and V. americana form the second association and are
common in areas where salinities are generally less than
15 parts per thousand (ppt), while E. canadensis, C. dem-
ersum, and N. guadalupensis form the association that is
found primarily in freshwater. H. verticillata was not in
the Bay in 1978 nor is it found in the lower Bay tributaries
today, but it would most likely be a member of the fresh-
water association. Thus, the process of setting SAV spe-
cies distribution/diversity targets must incorporate the
relationship of the different species in the formation of
community types.
Species Distribution/Diversity Restoration
Targets
Recent (Orth et al. 1989; Orth and Nowak 1990) and
potential distributional limits for the twelve most common
species recorded in the SAV aerial and ground survey
programs are presented as individual species distribution
restoration targets in Figures VI-5 through VI-16. Achieve-
ment of these SAV species specific distribution restoration
targets through repropagation to their distributional limits
(salinity tolerances) are based on meeting the SAV habitat
requirements for one and two meter restoration on a bay-
wide basis and the presence of sufficient propagules.
Below is a brief discussion for each of the twelve most
common Bay SAV species including a map of overlaying
recent species distribution with the species distribution
restoration target. The scale of the individual species
distribution restoration target maps is such that the exact
species distribution has not been delineated and appears to
include waters deeper than 2 m. The maps included here
are only intended to outline approximate species distribu-
tions and should be overlaid onto the smaller scale tiered
SAV distribution restoration goal maps for purposes of
delineating a more detailed extent of the species distribu-
tion /diversity targets. When all these maps are combined,
they provide additional documentation for the SAV spe-
cies distribution/diversity targets for Chesapeake Bay
(presented by Chesapeake Bay Program segment in Ap-
pendix C, Table C-2).
Zostera marina
Z. marina (eelgrass) is the only true seagrass found in
Chesapeake Bay. It has a salinity tolerance of 10-35 ppt,
limiting it to the more saline portions of the Chesapeake
Bay. Historically, Z. marina has grown in the lower
sections of the major tributaries on the Bay' s lower western
shore, including the James, York, Piankatank,
Rappahannock, Potomac, and Patuxent rivers. It had been
found along the Virginia and Maryland Eastern Shore up
to the Eastern Bay area just south of the Chesapeake Bay
Bridge. Seed records for this species in the upper Bay are
rare, occurring primarily in the lower Patuxent River (Brush
and Hilgartner 1989). Seeds occurred sporadically for 200
years in pre-colonial times and did not show appreciable
changes in numbers from 1720 until 1880. Between 1930
and 1980, seeds occurred in small numbers, attributable in
part to sampling artifacts; however, personal records have
indicated the presence of Z. marina adjacent to Solomons
Island through 1970. Since the 1970s, it has been absent
in the entire Patuxent River (Boynton, UMCBL, personal
communication). Z. manna was last reported in the Patuxent
River in 1971 through the U.S. Fish and Wildlife survey
(Stevenson and Confer 1978).
Presently, Z. marina is abundant along the Eastern Shore
from Cape Charles to Smith Island with the largest beds
concentrated between Tangier and Smith islands, Great
Fox Islands, Big Marsh at the mouth of Chesconessex
Creek, and along the major creeks entering the Bay from
Chesconessex Creek to Cape Charles. It is abundant on
the western shore in Back and Poquoson rivers, off Plum
Tree Island, the lower York River on the north shore,
Mobjack Bay, and in the Fleets Bay area just above the
mouth of the Rappahannock River. It is completely absent
from the Potomac and Patuxent rivers, occurs in only one
small area in the lower James River, is substantially re-
duced in the Piankatank and Rappahannock rivers, and is
abundant in the lower York only from Gloucester Point to
the mouth along the north shore (Orth and Nowak 1990,
Orth et al. 1991).
Z. marina has increased in abundance in some areas that
were either close to beds that never declined (e.g., the lower
York River) or in areas where successful transplanting has
occurred (e.g., the lower Piankatank and Rappahannock
rivers) (Orth and Nowak 1990). Figure VI-5 is a map of
the recent distribution overlaid with the Z. marina distri-
bution restoration target for Chesapeake Bay.
121
CSC.SAV.12/92
-------
SAV Technical Synthesis
Hydrilla vertidllata
H, vertidllata (hydrilla) did not occur in the Chesapeake
Bay ortributaries until 1982 when it was first recorded near
Dyke Marsh in the upper Potomac River (Stewart et al.
1984). Beginning in 1983, H. vertidllata spread rapidly
in the Potomac River and is now found in dense stands on
both sides of the river down to Aquia Creek. Approxi-
mately 2000 hectares of the river bottom contain H. vertidllata
(Orth and Nowak 1990, Orth et al. 1991). Interestingly,
H. vertidllata declined in some areas in 1989, notably in
the upper tidal river (Orth and Nowak 1990, Orth et al.
1991) presumably due to cooler than normal spring weather,
above average rainfall, and poor water clarity. Because of
its recent introduction, there is no seed record.
H. vertidllata can tolerate salinities up to 6 ppt (Carter et
al. 1987). H. vertidllata has also been recorded in the
Susquehanna Flats (Kollar, HCC, personal communica-
tion) where it grows mixed with other SAV species in small
patches. There is no information on when and how it had
become established nor is there any indication that it has
been spreading at the rates documented for the Potomac
River. H. vertidllata's salinity tolerance would limit its
distribution to the upper portions of all tributaries and the
upper Bay above the Chesapeake Bay Bridge (Figure VI-
6). Because H. vertidllata is an exotic and recent intro-
duction to Chesapeake Bay (and in some situations
considered a nuisance), a restoration target was not estab-
lished for this species.
Myriophyllum spicatum
M. spicatum (Eurasian watermilfoil) is another exotic
species that was introduced into the United States from
Asia or Europe in the early 1900s. It is tolerant of slightly
brackish waters up to approximately 10 ppt with optimal
growth occurring between 0 and 5 ppt (Stevenson and
Confer 1978). During the 1950s and early 1960s, this
species underwent a still unexplained rapid expansion in
the upper Bay and tributaries, including the Potomac and
Patuxent rivers. It was considered a major nuisance as it
partially obstructed waterways (similar to the hydrilla
situation occurring today in the Potomac River). It was
estimated that M. spicatum covered more than 100,000
acres during this period. As rapidly as it expanded, M.
spicatum also declined in the mid-1960s. Scientists attrib-
uted the decline to a viral-like disease, although the proof
was never conclusive. A seed record for this species was
available only from the Susquehanna Flats (Brush and
Hilgartner 1989). Seeds were present from 1930 to 1970,
mirroring the changes recorded in distribution surveys.
Today, M. spicatum is present primarily in large stands in
the upper Potomac River, including the Port Tobacco River
and Nanjemoy Creek, and is found interspersed with H.
vertidllata above Aquia Creek (Carter et al 1983, 1985).
It is also found in much smaller areas^in the Susquehanna
Flats, the Sassafras River, and the Saltpeter and Seneca
Creek region on the western shore. M. spicatum has been
commonly reported from many other areas by the Citizens
and Charterboat Captains surveys throughout its upper Bay
distributional range (Orth and Nowak 1990, Orth et al.
1991). Given its growth potential, M. spicatum has the
ability to occupy much more available habitat in the upper
Bay as well as the upper sections of all the tributaries and
creeks (Figure VI-7).
Ruppia maritima
R. maritima (widgeongrass) has the widest salinity toler-
ance of all SAV species in the Bay and is able to survive
equally well in hypersaline lagoons as well as low salinity
brackish bays and estuaries. Although this species can
survive in freshwater, it has not been reported to inhabit
tidal fresh sections of the Bay. Given this salinity range
tolerance, R. maritima has one of the greatest potential
distribution limits of all Bay SAV.
The seed record for R. maritima has showed a continuous
record from pre-colonial times with abundance of seeds
declining in the 20th century (Brush and Hilgartner 1989).
Seed distribution has been restricted to the downstream,
mesohaline portions of the tributaries, similar to current
distributional patterns. The period of 1720-1820 had the
greatest number of seeds while 1970-1987 was the period
of least seed abundance.
Presently, & maritima is normally found in close associa-
tion with Z. marina in the lower Bay. Generally, R.
maritima is found in the shallow portions of a bed and
intertidally while Z. marina dominates the deeper sections,
with both species found at intermediate depths (Orth and
Moore 1988).
Shown by the seed record, R. maritima declined in the
1960s and 1970s along with many of the other species.
Beginning around 1985, R. maritima began to recover
naturally in manjr sections of the Bay. By 1989, the species
had shown major increases in the lower Rappahannock,
Piankatank, and Potomac rivers, and in the mid-sections
of the Bay along the Eastern Shore including Eastern Bay,
the Choptank River, and the Barren Island-Honga River
area (Carter etal 1983,1985; Orth and Nowak 1990). This
species was the most often cited species in many of the late
122
CSXSAV.12&
-------
1980s surveys. Presently, this species may occupy more
bottom area than any other species.
R. maritima is considered an opportunistic species with an
extremely rapid growth rate and large seed production.
The lack of any other competitor SAV species may have
allowed this species to spread rapidly. Its wide salinity
range and past historical record indicate that R. maritima
could grow in shallow water areas throughout the Bay
(Figure VI-8).
Heteranthera dubia
Surprisingly, H. dubia (water stargrass) was not reported
in Chesapeake Bay or its tidal tributaries until the 1980s.
Seeds have not been reported in the historical record (Brush
and Hilgartner 1989). A freshwater species, it has been
reported as a commonly occurring species only in the
Susquehanna Flats and tidal fresh portions of the Potomac
Riverinthe 1980s (Orihet al. 1989; Orth and Nowak 1990;
Kollar, HCC, personal communication; Carter and Rybicki
1986). The ability to tolerate only slightly brackish waters
restricts its distributional limits to the tidal fresh or very
low salinity areas of the Bay and tributaries .(Figure VI-9).
Vallisneria americana
V. americana (wild celery) is one of the more valuable
freshwater species in the Bay and tributaries. It is tolerant
of water up to 11-13 ppt (Carter and Rybicki, USGS,
personal communication; Barko, USCOE, personal com-
munication). The seed record for this species showed it
to be abundant in pre-colonial times through 1880 in the
upper Bay and tributaries, principally from Furnace Bay,
the Back, Middle, Severn, Patuxent, and Chester rivers
(Brush and Hilgartner 1989). There was a large increase
in seeds from 1880 through 1930 and sporadic occurrences
through 1970. From 1970 through 1987, the seed record
showed a dramatic decline and was recorded from only one
core in the Middle River.
Recent surveys have shown V. americana to be most
abundant in the Susquehanna River and Flats region and
in the tidal fresh, oligohaline, and mesohaline section of
the Potomac River (Carter et al. 1983, 1985). It has also
been reported less frequently from the Elk, Sassafras,
Middle, and Gunpowder rivers and many small creeks
(Orth and Nowak 1990, Orth et al. 1991).
Past distribution of this species indicates that it was one
of the more common species in the Bay region, indicating
that y. americana can potentially occupy much more
habitat than it presently occupies (Figure VI-10).
Chesapeake Bay SAV Restoration Targets
Zannichellia palustris
Z. palustris (horned pondweed) is an annual that, like &
maritima, is one of the most widely distributed species,in
Chesapeake Bay and its tributaries. Based on its present
distribution, this species can apparently tolerate salinities
up to 20 ppt. The seed record has shown Z. palustris to
be one of the most persistent species in the oligohaline and
mesohaline areas of the upper Bay for the last 2000 years
(Brush and Hilgartner 1989). The period of 1720-1880
showed the greatest abundance of seeds, especially in the
Severn and Back rivers and Langford and Rock creeks.
Between 1880 and 1980, seed abundances fluctuated but
the species was consistently present.
Recent distribution studies reported Z. palustris to be
abundantin the Choptank, Patuxent, Potomac, Back, Middle,
Gunpowder, andRappahannockrivers and the Eastern Bay
area (Carter etal. 1983,1985; Orth and Nowak 1990, Orth
et al 1991). It is likely that this species is present today
in many other areas in much greater abundance than a
decade ago. Since this species has been a consistent part
of the historical record and has a large seed output with high
annual variation, Z. palustris will most likely continue
growing in the Bay but show a high degree of variability.
Figure VI-11 is a map of the recent distribution overlaid
with the Z. palustris distribution restoration target for
Chesapeake Bay.
Najas guadalupensis
N. guadalupensis (southern naiad or bushy pondweed) is
the more common of four naiad species found in the Bay.
It is tolerant of slightly brackish waters up to 10 ppt. This
species was common in the seed record of pre-colonial
times but was most abundant from 1720-1880, especially
in Langford and Rock creeks and the Chester, Patuxent,
Middle, and Back rivers (Brush and Hilgartner 1989).
Although seeds were still abundant in the Middle and
Patuxent rivers and Langford Creek, a decline in the seed
record began in 1880 and continued until 1980. During
1970-1987, seeds were found in some areas such as the
Middle and Back rivers but were generally much less
abundant, continuing the overall decline that started in the
1880s.
Present surveys have found A'! guadalupensis primarily in
the Susquehanna River and Flats region and in the transi-
tion and tidal fresh water zones of the Potomac River
(Carter et al. 1983, 1985; Orth and Nowak 1990, Orth et
al. 1991). Ground surveys in the 1980s reported this
species in the Choptank and Middle rivers, Rock Creek,
123
CSC.SAV.12/92
-------
SAV Technical Synthesis
and several smaller creeks throughout the Bay. The po-
tential distributional limits are in the upper Bay and upper
portions of the major tributaries (Figure VI-12).
Potamogeton perfoliatus
P. perfoliatus (redhead grass) has been another of the more
common species previously found in the upper Bay and
tributaries. It is a freshwater species that can tolerate
salinities up to 20 ppt. The seed record for P. perfoliatus
shows that this species was common in pre-colonial times,
with sporadic occurrences from 1720-1930 (Brush and
Hilgartner 1989). Theperiodfrom 1930-1970wasaperiod
of proliferation after which there was an overall decline,
with seeds found only in the Middle and Severn rivers and
Langford and Rock creeks.
The most recent ground surveys have reported sporadic
occurrences of P. perfoliatus throughout the northern Bay
and upper portions of tributaries in the northern Bay-in
particular the Chester River, Susquehanna River and Flats,
and the mid-section of the Potomac River around Mathais
Point, Port Tobacco River, and Nanjemoy Creek (Carter
etal. 1983,1985; Orth and Nowak 1990, Ortlma;. 1991).
Its high salinity tolerance, compared to several of the other
freshwater species, along with its past historical distribu-
tionindicateabroaderpotential distribution forthis species
(Figure VI-13).
Potamogeton pectinatus
P. pectinatus (sago pondweed) is the second species of this
genus found in the Bay and tributaries and has been
reported frequently in the past. It is a freshwater species
that can tolerate salinities up to 9 ppt. Brush and Hilgartner
(1989) do not report on any seed record for this species.
Present distributional surveys have reported this species to
be most common in several sections of the Bay-notably
the Potomac River from Washington, DC to the Port
Tobacco River and Nanjemoy Creek area, the Middle,
Chester and Choptank rivers, and the Susquehanna River
and Flats area (Carter et al. 1983, 1985; Orth and Nowak
1990, Orth etal 1991). P. pectinatus has been one of the
more frequently reported species in the upper Bay in recent
years but is still far below population densities reported
earlier. Its presence in many different sections of the upper
Bay and its potential distribution limits indicate that this
species can occupy a much wider area than many of the
other species (Figure VI-14).
Ceratophyllum demersum
C. demersum (coontail or hornwort) is a freshwater species
that is capable of tolerating salinities up to 6 ppt. Inter-
estingly, this species grows independently of a particular
substrate and can subsist by floating in the water. It
normally produces asexually, with fragments easily able
to develop into viable shoots. Brush and Hilgartner (1989)
do not report on a seed record for this species. The poor
record may result from this plant's infrequent production
of seeds.
Present distribution of this species is primarily in the
Susquehanna River and Flats area, the upper Patuxent
River, and the Potomac River transition and tidal freshwa-
ter zone (Carter et al. 1983, 1985; Orth and Nowak 1990,
Orth etal. 1991). Since this species is not rooted and can
tolerate some brackish water, it could likely have a much
wider distribution than present (Figure VI-15). However,
the lack of rooting may restrict it to areas with little current
movement or to co-occur with other species that are rooted.
Elodea canadensis
E. canadensis (common elodea) is a freshwater species
with a salinity tolerance of approximately 10 ppt. This
species is a common home aquarium plant and closely
resembles hydrilla. It is commonly reported in the Bay
region.
E. canadensis had a fairly continuous seed distribution
record until colonial settlement (Brush and Hilgartner
1989). There appeared to be an increase in populations
from 1720-1880; but between 1880 and 1930, it disap-
peared from the Severn River and Rock Creek. Between
1930 and 1970 it disappeared from most of Back Creek
while at the same time appearing in Langford Creek.
Between 1970 and 1987, seeds were found only in the
upper Middle River.
Recent distributional surveys have found E. canadensis in
the Susquehanna River and Flats area, the Chester River
region, and the tidal fresh and oligohaline zones of the
Potomac River (Carters al. 1983,1985; Orth and Nowak
1990, Orth etal. 1991). Earlier survey sin the 1970s found
a more broad distribution than present (Stevenson and
Confer 1978), indicating the potential of this species to
expand to many other new areas (Figure VI-16).
124
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Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Zostera marina
Susquehanna
Patapsco
Potomac
James
Sassafras
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure VI-5. Distribution restoration target for Zostera marina in Chesapeake Bay is shown as the combined potential and recent species distribution.
Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more accurate
distribution depth limits.
125
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SAV Technical Synthesis
Chesapeake Bay Recent and Potential Distribution for Hydrilla verticillata
Susquehanna
Sassafras
Patapsco
Potomac
James
Nanticokei
Pocomoke
Rappahannock
| = Potential distribution
I = Recent distribution
Figure Vl-6. Recent and potential distribution of Hydrilla verticillata in Chesapeake Bay is shown. Some areas deeper than the anticipated depth
of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more accurate distribution depth limits. The open box Q and
open circle (Q) are used to delineate potential and recent distribution, respectively, in sections of the tributaries where the shading patterns are
not visible due to the scale of the figure.
126
CSOSW.1292
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Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Myriophyllum spicatum
Susquehanna
Patapsco
Rappahannock
James
Sassafras
Nanticoke
y. v (^"i-fw Pocomoke
= Potential distribution
= Recent distribution
Figure VI-7. Distribution restoration target for Myriophyllum spicatum in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits.
127
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SAV Technical Synthesis
Chesapeake Bay Distribution Restoration Target for Ruppia maritima
Susquehanna
Patapsco
Potomac
James
Sassafras
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure Vl-8. Distribution restoration target for Ruppia maritima in Chesapeake Bay is shown as the combined potential and recent species distribution.
Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more accurate
distribution depth limits.
128
CSOSAV.12S2
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Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Heteranthera dubia
Susquehanna
Patapsco
Sassafras
Potomac
James
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure VI-9. Distribution restoration target for Heteranthera dubia in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. The open box Q is used to delineate potential distribution in sections of the tributaries where the shading pattern
is not visible due to the scale of the drawing.
129
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-------
SAV Technical Synthesis
Chesapeake Bay Distribution Restoration Target for Vallisneria americana
Susquehanna
Sassafras
Patapsco
Potomac
James
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Rgure VI-10. Distribution restoration target for Vallisneria americana in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. The open circle (Q) is used to delineate recent distribution in sections of the tributaries where the shading pattern
Is not visible due to the scale of the figure.
130
CSC.SAV.1JA2
-------
Chesapeake Bay:SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Zannichellia palustris
Susquehanna
Sassafras
Patapsco
Potomac
James
Nanticoke
Pocomoke
^ = Potential distribution
I = Recent distribution
Figure VI-11. Distribution restoration target for Zannichellia palustris in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. . •
131
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SAV Technical Synthesis
Chesapeake Bay Distribution Restoration Target for Najas guadalupensis
Susquehanna
Patapsco
Potomac
James
Sassafras
Nanticoke
Pocomoke
j = Potential distribution
• = Recent distribution
Figure VM2. Distribution restoration target for Najas guadalupensis in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. The open circle (Q) is used to delineate recent distribution in sections of the tributaries where the shading pattern
is not visible due to the scale of the figure.
132
CSCSAV.1M2
-------
Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Potamogeton perfoliatus
Susquehanna
Patapsco
Potomac
James
Sassafras
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure VI-13. Distribution restoration target for Potamogeton perfoliatus in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits.
133
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SAV Technical Synthesis
Chesapeake Bay Distribution Restoration Target for Potamogeton pectinatus
Susquehanna
Patapsco
Potomac
James
Sassafras
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure VI-14. Distribution restoration target for Potamogeton pectinatus in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits.
134
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Chesapeake Bay SAV Restoration Targets
Chesapeake Bay Distribution Restoration Target for Ceratophyllum demersum
Susquehanna
Patapsco
Potomac
James
Nanticoke
Pocomoke
= Potential distribution
= Recent distribution
Figure VI-15. Distribution restoration target for Ceratophyllum demersum in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. The open box (Q) and open circle (Q) are used to delineate potential and recent distribution, respectively, in
sections of the tributaries where the shading patterns are not visible due to the scale of the figure.
135
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SAV Technical Synthesis
Chesapeake Bay Distribution Restoration Target for Elodea canadensis
Susquehanna
Patapsco
Potomac
Nanticoke
James
Pocomoke
= Potential distribution
= Recent distribution
Figure VM6. Distribution restoration target for Elodia canadensis in Chesapeake Bay is shown as the combined potential and recent species
distribution. Some areas deeper than the anticipated depth of SAV growth (2m) are shaded due to the scale of the map; see Figure VI-4 for more
accurate distribution depth limits. The open box (Q) and open circle (Q) are used to delineate potential and recent distribution, respectively, in
sections of the tributaries where the shading patterns are not visible due to the scale of the figure.
136
CSOSAV.12/92
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Chapter VH
Nearshore & Mid-channel Water Quality Comparisons
n the preceding chapters, levels of selected water
quality parameters characteristic of viable sub-
merged aquatic vegetation (SAV) habitat in the
Chesapeake Bay were defined. The objective of this study
is to determine if existing mid-channel water quality data
is appropriate for characterizing seasonal water quality
conditions in adjacent nearshore areas. If the water quality
is comparable, then data from existing mid-channel moni-
toring programs might be used to determine if water quality
conditions are meeting habitat requirements for SAV. In
addition, the results will provide guidance for modifying
mid-channel monitoring programs or assisting in the de-
velopment of additional nearshore monitoring programs in
areas where nearshore and mid-channel data have proven
incomparable.
Study Areas and Sampling Programs
York River
Six stations within the lower 30 kilometers of the York
River, three mid-channel and three nearshore, were se-
lected for comparison in this study (Figure VII-1). These
areas are representative of polyhaline and mesohaline
regions of Virginia's tributaries that currently or histori-
cally have supported SAV. The nearshore stations were
sampled by the Virginia Institute of Marine Science (VIMS)
as part of the Virginia Nearshore Submerged Aquatic
Vegetation Monitoring Program. Mid-channel stations
LE4.2 and LE4.3 are sampled as part of the Virginia
Chesapeake Bay Tributary Water Quality Monitoring
Program, and mid-channel station WE4.2 was sampled as
part of the Chesapeake Bay Mainstem Water Quality
Monitoring Program. Both of the mid-channel station
monitoring programs were coordinated by the Virginia
State Water Control Board (VSWCB).
Mid-channel data included only those samples obtained at
one meter depth or, in some cases, at the surface. Nearshore
samples were obtained in triplicate at a depth of 0.25 m.
Water column depths in the nearshore at mean low water
(MLW) were approximately one meter. The Guinea Marsh
and Gloucester Point stations were located in areas veg-
etated with SAV. The Claybank station was located in a
shoal area which formerly supported SAV but is now
devoid of vegetation. Characteristics of the York River
stations are presented in Table VII-1.
Table VII-1. Characteristics of York River nearshore and mid-channel water quality monitoring stations.
Station Years Vegetated Salinity
Guinea Marsh
VIMS nearshore site
WE4.2
VSWCB mid-channel site
Gloucester Point
VIMS nearshore site
LE4.3
VSWCB mid-channel site
Claybank
VIMS nearshore site
LE4.2
1985-1988
1985-1988
1985-1988
1985-1988
1985-1988
1985-1988
Yes
No
Yes
No
No
No
Polyhaline
Polyhaline
Polyhaline
Polyhaline
Mesohaline
Mesohaline
VSWCB mid-channel site
137
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SAV Technical Synthesis
York River Nearshore and Mid-channel
Water Quality Monitoring Stations
Choptank River Nearshore and Mid-channel
Water Quality Monitoring Stations
'»
WE4.2 Guinea
Marsh
Figure VIM. York River nearshore (D) and mid-channel ((
water quality monitoring stations used in the data analysis.
MET5.2
Figure VII-3. Choptank River nearshore (D) and mid-channel
(•) water quality monitoring stations used in the data analysis.
Potomac River Nearshore and Mid-channel
Water Quality Monitoring Stations
Blossom
Point
FigureVII-2. UpperPotomacRivernearshore(D) and mid-channel
(•) water quality monitoring stations used in the data analysis.
Upper Bay Nearshore and Mid-channel
Water Quality Monitoring Stations
Susquetianna
RKrar
MET3.1
Figure VII-4. Upper Chesapeake Bay nearshore (D) and mid-
channel (• ) water quality monitoring stations used in the data
analysis.
138
CSOSAV.KS2
-------
Upper Potomac River
Nine water quality monitoring stations, located in the
upper Potomac River between the U.S. Route 301 bridge
at Morgantown and Piscataway Creek, were chosen to
compare nearshore and mid-channel water quality (Figure
VII-2). Four of these stations were mid-channel stations
monitored by the Maryland Department of the Environ-
ment (MDE) as part of the Chesapeake Bay Water Quality
Monitoring Program. The other five stations, located in
the nearshore, were monitored by the U.S. Geological
Survey (USGS) in 1985 and 1986 as part of the USGS
Wetland Studies Project.
The nearshore samples collected by USGS were taken at
0.33 m below the surface in less than 3 m of water depth
outside S AV beds. MDE mid-channel samples were taken
at 0.5 m depth from a boat in unvegetated areas of greater
than 3 m depth. Table VII-2 presents the characteristics
of each station. Salinities in this arearangedfrom oligohaline
to tidal fresh and decreased with distance upstream. The
sediments are silt-clay in the mid-channel, becoming sand-
rich in shallow water.
Choptank River
Fourteen water quality monitoring stations, located be-
tween river kilometer 6 and river kilometer 82, were
chosen for analysis in the Choptank River (Figure VII-3).
Three mid-channel stations were monitored by MDE as
part of the Chesapeake Bay Water Quality Monitoring
Program. The remaining eleven stations, two mid-channel
and nine nearshore, were monitored by the University of
Maryland Horn Point Environmental Laboratory (HPEL)
as part of their SAV transplanting research program.
The nearshore sites in the Choptank River were located
along the margins of the river at water depths of 3 m or less
and were sampled at a depth of 0.33 m. Nearshore stations
in the lower part of the Choptank were in protected coves
while those in the upper river were located in shallow areas
adjacent to the mainstem of the river. The mid-channel
stations were located along the axis of the river in water
depths greater than 3 m and were sampled at a depth of 0.5
m. The HPEL stations were sampled monthly while the
MDE stations were sampled twice a month.
Table VII-3 presents the characteristics of the water quality
monitoring stations in the Choptank River. Due to the wide
salinity and water quality gradients over which the Choptank
River was sampled, stations were grouped into three gen-
eral geographic areas for analysis-the Choptank embayment,
the Cambridge area, and the Tuckahoe confluence area.
Nearshore and Mid-channel Water Quality Comparisons
Upper Chesapeake Bay
Thirteen water quality monitoring stations, located in the
Sassafras River, Elk River and Susquehanna Flats, were
chosen for comparison in the upper portion of Chesapeake
Bay (Figure VII-4). Nine of these stations, four mid-
channel and five nearshore, were monitored monthly by
Harfbrd Community College (HCC) from April through
October in 1988 and 1989 as part of an SAV transplanting
program. The remaining three mid-channel stations were
monitored by MDE as part of the Chesapeake Bay Water
Quality Monitoring Program. Two of these stations, lo-
cated in the Elk and Sassafras rivers, were monitored
monthly. The other MDE mid-channel station, located in
the mainstem of the Bay near the Susquehanna River, was
monitored twice a month.
The nearshore stations in the upper Bay region were lo-
cated along the margins of the Susquehanna Flats and the
Sassafras and Elk rivers at water depths of less than 3 m.
All of the nearshore samples were collected at a depth of
0.5 m adjacent to beds of SAV. All of the mid-channel
samples were collected in water greater than 3 m deep at
a depth of 0.5 m and away from any vegetation.
Salinities in this upper Bay region ranged from oligohaline
to tidal fresh with most of the sampling stations located in
tidal fresh areas. Sediments along the eastern shore of the
Susquehanna Flats consisted of sand and pebbles in near-
shore areas. These sediments became finer textured (i.e.,
silt and clay) moving toward the central area of the Sus-
quehanna Flats. Station characteristics are presented in
Table VII-4.
Methods
The following parameters were chosen for comparison
between the nearshore and mid-channel stations: light
attenuation coefficient, total suspended solids, chlorophyll
a, dissolved inorganic nitrogen, and dissolved inorganic
phosphorus. These parameters are consistent with those
listed as SAV habitat requirements for one meter restora-
tion. In the York River region, lack of adequate data for
chlorophyll a prevented comparisons of that parameter.
Analytical methods for each parameter varied with the data
sets measured. Summaries of the methods used by VIMS,
HPEL, and HCC to collect and analyze data have been
previously described in the case study sections. Method
summaries for the data collected by the MDE, VWCB, and
the USGS are provided in Appendix B.
139
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SAV Technical Synthesis
Table VII-2. Characteristics of the upper Potomac River water quality monitoring stations.
Station Years Vegetated Salinity
Blossom Point 1985
USGS nearshore; site location
variable; mostly in vicinity of
Maryland Point
XDA1177 (RET 2.2) 1984-1989
MDE mid-channel site off
Maryland Point
XDA 4238 (RET 2.1) 1984-1989
Mid-channel site off Smith Point
Wades Bay 1985-1986
USGS nearshore site; shoreline
low profile and forested
XEA1840 (TF2.4) 1984-1989
MDE mid-channel site off mouth
of Mattawoman Creek
Mouth Mattawoman 1985-1986
USGS nearshore site in mouth of
Mattawoman Creek just outside
first point (inside if very windy)
Gunston Cove 1985-1986
USGS nearshore site in mouth of
Gunston Cove; well offshore
near channel marker #64
XFB1433 (TF2.2) 1984-1989
MDE mid-channel site off mouth
of Dogue Creek
Elodea Cove 1985-1986
USGS nearshore site; low profile
shoreline; forested
Yes
No
No
Yes
No
No
Yes
No
Yes
Oligohaline
Oligohaline
Oligohaline
Oligohaline
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Secchi depths were converted to light attenuation coeffi-
cients (Kd) based upon linear relationships derived be-
tween Secchi depth and attenuation of photosynthetically
active radiation. A relationship of Kd=1.38/Secchi depth
was used for the Potomac River stations (Carter and Rybicki
1990) while Kd=1.45/Secchi depth was used for all other
Secchi data (Moore, unpublished data).
Comparisons were made for a growing season of April to
October in the Choptank and upper Bay areas. In the upper
Chesapeake Bay, comparisons for all of the variables
except light attenuation coefficient were restricted to 1989
due to analytical problems with the nearshore data. For the
nearshore Potomac stations, data were available only from
May through September of 1985 and April through August
of 1986. Therefore, comparisons for the Potomac were
confined to this time frame. A bi-modal growing season
based upon ambient water temperature was used for com-
parisons in the York River. The seasons for this analysis
were chosen to be consistent with the criteria used for
application of the SAV habitat requirements.
Comparisons were made between pairs or groupings of
nearshore and mid-channel stations which were considered
to be in the same general region of the systems examined
(Table VII-5). Data comparisons between the paired
140
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Nearshore and Mid-channel Water Quality Comparisons
Table Vll-3. Characteristics of Choptank River nearshore and mid-channel water quality monitoring stations.
Station Years Vegetated Salinity
MEE2.1 1984-1990
MDE mid-channel
site in the Choptank
River Embayment
Buoy 12A 1987-1989
HPEL mid-channel site
in the Choptank River
Embayment
Cook's Cove 1986-1989
HPEL nearshore site within
Cook's Cove in the
Choptank Embayment
Chapel Creek 1986-1989
HPEL nearshore site
within a cove in the
Choptank Embayment
Irish Creek 1986-1989
HPEL nearshore site
within a cove in the
Choptank Embayment
Foxhole Creek 1986-1989
HPEL nearshore site
within a cove in the
Choptank Embayment
Horn Point 1986-1989
HPEL nearshore site near
Cambridge along the shore
of the Choptank River
Dickinson Bay 1986-1989
HPEL nearshore site near
Cambridge within a cove
Buoy 25 1987-1989
HPEL mid-channel site
near Cambridge
MET5.2 1984-1989
MDE mid-channel site
near Cambridge
Bolingbroke 1986-1989
HPEL nearshore site near
Cambridge within a cove
METS.l 1984-1989
MDE mid-channel site near
the confluence of Tuckahoe
Creek
Gilpin Point 1986-1989
HPEL nearshore site along
the shore near the Tuckahoe
Creek confluence
Tuckahoe Creek 1986-1989
HPEL nearshore site along
the shore of Tuckahoe Creek
near the confluence
No
No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
No
No
No
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Mesohaline
Tidal Fresh
Tidal Fresh
Tidal Fresh
141
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SAV Technical Synthesis
Table Vll-4. Characteristics of the upper Chesapeake Bay water quality monitoring stations.
Station
Years
Vegetated
Salinity
Log Pond
HCC mid-channel site
in the mouth of the
Susquehanna River
Outfall
HCC nearshore site in
the mouth of the
Susquehanna River
Fishing Battery (in)
HCC nearshore site in
the Susquehanna Flats of
upper Chesapeake Bay
Fishing Battery (out)
HCC mid-channel site
in the Susquehanna Flats
of upper Chesapeake Bay
Central Bay
HCC mid-channel site
in the central Susquehanna
Flats
MCB1.1
MDE mid-channel site
near the outfall of the
Susquehanna River
Piney Creek (in)
HCC nearshore site in
Piney Creek along
the Elk River
Piney Creek (out)
HCC mid-channel site in
Piney Creek along the Elk
River
Elk Neck (in)
HCC nearshore site in
cove along the shore
of the Elk River
Elk Neck (out)
HCC mid-channel site
adjacent to Elk Neck (in)
MET2.3
MDE mid-channel site
adjacent to Elk Neck
Georgetown
HCC nearshore site along
the shore of the Sassafras
River near Georgetown
MET3.1
MDE mid-channel site
adjacent to HCC nearshore
site Georgetown
1988-1989
1988-1989
1988-1989
1988-1989
1988-1989
1984-1989
1988-1989
' 1988-1989
1988-1989
1988-1989
1984-1989
1988-1989
1984-1989
No
No
Yes
No
No
No
No
No
Yes
No
No
No
No
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
Tidal Fresh
142
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Nearshore and Mid-channel Water Quality Comparisons
Table VII-5. Groupings of stations for nearshore/mid-channel comparison analysis with the mid-channel stations underlined.
Stations
Groups
York Stations
Guinea Marsh Group 1
Gloucester Point Group 2
LE4.3
Claybank Group 3
LE4.2
Potomac Stations
Blossom Point Group 1
XDA1177
Wades Bay Group 2
XDA4238
Mouth Mattawoman Group 3
XEA184Q
Gunston Cove Group 4
XFB1433
Elodea Cove Group 4—both nearshore sites
XFB1433 compared to XFB1433.
Choptank Stations
MEE2.1 Group 1—Choptank embayment/pairwise
Buoy 12A comparisons made between all stations.
Irish Creek
Chapel Creek
Cook's Cove
Foxhole Creek
MET5.2 Group 2—Cambridge area/pairwise comparisons
Buoy 25 made between all stations.
Horn Point
Dickinson Bay
Bolingbroke Creek
MET5.1 Group 3—Tuckahoe confluence.
Gilpin Point
Tuckahoe Creek
Upper Bay Stations
Log Pond Group 1—Susquehanna Flats/pairwise
Outfall comparisons made between all stations.
Fishing Battery (in)
Fishing Battery (out)
Central Bay
MCB1.1
Piney Creek (in) Group 2—Elk River.
Piney Creek (out')
Elk Neck (in) Group 3—Lower Elk River/comparisons
Elk Neck (out) between all stations.
MET2.3
Georgetown Group 4—Sassafras River.
MET3.1
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SAV Technical Synthesis
Surface Temperatures in the York River
- Guinea Marsh and WE4.2 -
«
Jin Dec Jun Dec Jun Deo Jun Deo Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Figure VII-5. Comparison of nearshore (Guinea Marsh »*»») and mid-
channel (WE4.2—) water column surface temperatures in the York
River from 1984-1989.
stations were explored using descriptive statistics, histo-
grams, and time series plots of all available data. Formal
statistical comparisons between paired stations for each of
the investigated variables were made using SPSSX (SPSS,
Inc.) statistical software with the York River data and S AS
(SAS Institute, 1985) for all other areas. In each case, a
distribution free rank sum test (Wilcoxon/Mann-Whitney
U) was used to test if the distributions of the two-paired
sample populations for each variable were the same (Daniel
1987, Hipel and McLeod 1990, SAS 1985). All compari-
sons were made on a year-by-year basis to factor out
interannual changes in water quality. In the York River,
an annual period consisting of the spring, summer, and fall
(roughly April to October) was chosen to provide a com-
parable time frame to the year-by-year analyses of the
lower salinity regions. In addition, for this region indi-
vidual seasons were also analyzed using 1985-1988 data.
Surface Temperatures in the York River
- Gloucester Point and LE4.3 -
30-i
Jun D«o
1984
Jun Dec Jun Dec
1985 1986
Jun Dec
1987
Jun Dec Jun Dec
1988 1989
Figure Vll-6. Comparison of nearshore (Gloucester Point mm) and
mW-channe! (LE4.3 —) water column surface temperatures in the York
River from 1984-1989.
Surface Temperatures in the York River
- Claybank and LE4.2 -
Jun Dec Jon Doc Jun Deo Jun Dec
1984 1985 1986 1987
Jun Dec Jun Dec
1988 1989
Figure VH-7. Comparison of nearshore (Claybank mm ) and mid-
channel (LE4.2 —) water column surface temperatures in the York
River from 1984-1989.
Different methods and sampling schedules employed by
the various monitoring agencies were identified as factors
with the potential to have an effect on the results of this
study. Extensive data comparisons, method evaluations,
and quality assurance checks were employed to minimize
the effects of differing methods. One consequence of using
different analytical methods was widely differing detec-
tion limits for some of the investigated water quality
variables. In cases where >50% of the measurements for
a variable at a station were below the detection limit for
that variable, no comparison was made. The effect of
different sampling schedules on the outcomes of the sta-
tistical tests was unknown but likely to increase variability.
It is important to note that many of the nearshore sites were
located within coves or somewhat up or down the estuary
from neighboring mid-channel sites. These spatial factors
contributed to the observed variability due to localized
nearshore influences or longitudinal gradients in some
water quality variables.
Results
York River
Water Temperature
Water temperatures were quite similar between stations
(Figures VII-5, VII-6, and VII-7) with no evidence of
significant differences between nearshore and mid-chan-
nel stations (one exception was Claybank/LE4.2 for sum-
mer). No significant differences were observed at other
sites when stations were compared on a seasonal (Table
VII-6) or annual (Table VII-7) basis.
144
CaXSAV.12,'92
-------
Nearshore and Mid-channel Water Quality Comparisons
Table VII-6. Statistical comparison of nearshore/mid-channel station data for
Stations
Guinea Marsh/
WE4.2
Gloucester Point/
LE4.3
Claybank/
LE4.2
NS = not significant (p>.05)
ND = no available data
Season
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Winter
Spring
Summer
Fall
Temp.
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
p=.04
NS
Sal.
NS
NS
NS
NS
p=.0001
NS
p=.008
p=.001
p=.0001
p=.01
p=.001
p=.001
individual seasons in the York River
Kd
NS
NS
NS
NS
NS
NS
p=.0001
NS
NS
NS
NS
NS
TSS
NS
NS
NS
NS
NS
NS
p=,008
NS
ND
ND
ND
ND
DIN
NS
**
**
p=.02
**
**
**
**
*#
**
**
NS
1985-1988.
DIP
**
**
**
NS
**
**
p=.001
NS
**
**
p=.0001
NS
** = not comparable due to detection limit
Table VII-7. Statistical comparisons
Stations
Guinea Marsh/
WE4.2
Gloucester Point/
LE4.3
Claybank/
LE4.2
of nearshore/mid-channel
Year
1985
1986
1987
1988
1985
1986
1987
1988
1985
1986
1987
1988
Temp.
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
station data by years for the
Sal.
NS
NS
NS
NS
p=.0001
NS
NS
NS
p=.0001
p=.02
NS
NS
Kd
NS
NS
NS
NS
p=.002
NS
NS
NS
p=.002
NS
NS
NS
York River
TSS
NS
NS
p=.02
p=.05
p=.002
p=.02
**
NS
ND
ND
ND
NS
1985-1988.
DIN
**
**
p=.048
p=.009
**
##
**
**
**
**
#*
**
DIP
**
**
**
p=.0001
**
**
**
**
**
**
**
**
NS = not significant (p>.05)
ND = no available data
** = not comparable due to detection limit
145
CSC.SAV.12/92
-------
SAV Technical Synthesis
Surface Salinities in the York River
- Guinea Marsh and WE4.2 -
25-:
MO:
5-
I • I • I • I ' I ' I
Jun Dec Jun Dec Jun Dec Jun
1984
1985
1986
Dec Jun Dec Jun Dec
1987 1988 1989
Figure VIl-8. Comparison of nearshore (Guinea Marsh ****) and mid-
channel (WE4.2 —) water column surface salinities in the York River
from 1984-1989.
Surface Salinities in the York River
- Gloucester Point and LE4.3 -
30-,
25
,20
• • I ' l—• I '—r—'—I ' i •—I ' I—' i ' I '—i
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Rgure VII-9. Comparison of nearshore (Gloucester Point »*«) and
mid-channel (LE4.3—) water column surface salinities in the York
River from 1984-1989.
Salinities at the Guinea Marsh and WE4.2 stations dis-
played similar variability (Figure VII-8) when compared
on a seasonal or annual basis (Tables VII-6 and VII-7). At
the upriver Gloucester Point and LE4.3 stations, salinities
were slightly lower at the nearshore station during the
winter, summer, and fall (Figure VII-9). When compared
by year, significant differences were evident only during
1985 (Tables VII-6 and VII-7). This may be due to the
slightly upriver location of the nearshore stations. At
Claybank (Figure VII-10), salinities were significantly
lower than LE4.2 during all seasons and during 1985
through 1986 (Tables VII-6 and VII-7). This difference
in salinity may affect the comparison of other water quality
variables between these two sites.
Light Attenuation Coefficient
Increasing light attenuation coefficient levels were ob-
served during spring and summer (Figure VII-11) at both
Guinea Marsh and WE4.2. Although more variable and
occasionally higher levels were found in the nearshore,
when compared over seasonal and annual periods (Tables
VII-6 and VII-7), no significant differences were found. At
Gloucester Point and LE4.3, significantly higher levels
occurred at the nearshore site during the summer (Figure
VII-12 and Table VII-6), but only 1985 was significantly
different when compared over the annual growing season
(Table VII-7). Seasonally, light attenuation coefficients
were highest during the spring and early summer at Claybank
and LE4.2, with lowest levels during the winter (Figure
VII-13). One significant difference was detected between
the locations in 1985 (Tables VII-6 and VII-7).
30n
2Si
j-15-
MO-
5-
Surface Salinities in the York River
- Claybank and LE4.2 -
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Figure VII-10. Comparison of nearshore (Claybank «*»«) and mid-
channel (LE4.2 —) water column surface salinities in the York River
from 1984-1989.
Total Suspended Solids
Total suspended solids at WE4.2 showed greater variabil-
ity over time when compared to Guinea Marsh (Figure VII-
14). Although levels might be expected to be higher in the
nearshore due to local resuspension by wave action, no
significant differences were observed between sites when
compared on a seasonal basis (Table VII-6). However,
differences were significant for 1987 and 1988 when com-
pared annually (Table VII-7).
At Gloucester Point and LE4.3 (Figure VII-15), seasonally
determined medians were significantly different only dur-
ing the summer. Limited data during the summer of 1987
at LE4.3 prevented comparison during that period. On an
annual basis, the nearshore site was significantly higher
during 1985 and 1986 (Table VII-7). During 1988, three
very high values at LE4.3 were in contrast to the pattern
146
CS&SAV.IZflZ
-------
of higher levels of total suspended solids in the nearshore.
A detection limit, which varied from 3 to 6 mg/1 for the
LE4.3 site, also biased the data toward higher levels in the
mid-channel. During the period between September 1984
and June 1987, approximately 12 of the 32 records at LE4.3
were at the detection limit.
Total suspended solid concentrations were higher at the
Claybank site (Figure VII-16) compared to the downriver
nearshore stations. Seasonal concentrations were highest
during the summer period. A lack of total suspended solids
data at LE4.2 prior to June 1987 prevented comparison
with Claybank, except during 1988 when no statistically
significant difference between the stations was observed.
Dissolved Inorganic Nitrogen
Nearshore and Mid-channel Water Quality Comparisons
Light Attenuation in the York River
- Guinea Marsh and WE4.2 -
Figure VIM 1. Comparison of nearshore (Guinea Marsh s™*) and mid-
channel (WE4.2 —) light attenuation coefficients in the York River from
1984-1989.
Significantly higher levels of dissolved inorganic nitrogen
were observed during the fall at WE4.2 compared to the
nearshore Guinea Marsh site (Table VII-6). Although in
many years dissolved inorganic nitrogen levels in the mid-
channel were higher than nearshore during the winter, the
differences were not significant when data were compared
over the four years. Detection limits were too high during
much of the 1984-1986 period at the mid-channel station
WE4.2 (Figure VII-17) to compare with the adjacent near-
shore station. However, during 1987 and 1988, growing
seasons levels were significantly greater at the mid-chan-
nel station than the nearshore station (Table VII-7).
At LE4.3, the high detection limits for the Virginia tribu-
tary monitoring data made this data set a poor record of
nitrogen concentrations in this region of the York River
(Figure VII-18). Except during a short period in the fall
and winter, levels of dissolved inorganic nitrogen were at
or below detection. Therefore, no comparisons could be
made between Gloucester Point and LE4.3 (Tables VII-6
and VII-7). Maximum levels of dissolved inorganic nitro-
gen were reported lower at the mid-channel station LE4.3
than downriver at WE4.2. This was in contrast to the
nearshore stations GuineaMarsh (Figure VII-17) and Glouc-
ester Point (Figure VII-18) where the pattern was one of
increasing concentrations with distance upriver.
At Claybank and LE4.2, a high number of data at the
detection limit for dissolved inorganic nitrogen were evi-
dent at the mid-channel site (Figure VII-19). Therefore,
only one direct statistical comparisons could be made
between the two sites in the fall.
Comparisons for the York River region demonstrated
problems associated with detection limits in the polyhaline
and mesohaline portions of the western tributaries. Dis-
Light Attenuation in the York River
- Gloucester Point and LE4.3 -
s
2-
1.5-
! 1-
iO.5-
I ' I ' 1 > 1 1 1 1 1—i—71 ' 1 '—1 1 1 1 1 r-
Jun Deo Jun Deo Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Figure VII-12. Comparison of nearshore (Gloucester Point's--*.) and
mid-channel (LE4.3 —) light attenuation coefficients in the York River
from 1984-1989.
5-q
4.5-:
^2.5-j
1 a-i
I 1.5-:
-* 1-1
1-0.5-i
Light Attenuation in the York River
- Claybank and LE4.2 -
Jun
1984
1—'—I ' ' I—'—I—
Deo Jun Dec Jun
—i—>
Dec
1985
1986
—i—i—i—i—i—"—I—<—'I—i—I—i-
Jun Deo Jun Dec Jun Dec
1987 1988 1989
Figure VII-13. Comparison of nearshore (Ciaybank -«) and mid-
channel (LE4.2 —) light attenuation coefficients in the York River from
1984-1989 (*June 1987 Claybank light attenuation coefficient
measurement was 7.0 nr1).
147
CSC.SAV.12/92
-------
SAV Technical Synthesis
Total Suspended Solids in the York River
- Guinea Marsh and WE4.2 -
Jun D«c Jon Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Dissolved Inorganic Nitrogen in the York River
- Guinea Marsh and WE4.2 -
0.6-,
Jun
1984
1985
Jun Dec Jun Dec
1988 1989
Figure VIH4. Comparison of nearshore (Guinea Marsh «««,) and mid-
channel (WE4.2 —) surface total suspended solids concentrations in
the York River from 1984-1989.
Figure VII-17. Comparison of nearshore (Guinea Marsh ^m,) and mid-
channel (WE4.2 —) surface dissolved inorganic nitrogen concentrations
in the York River from 1984-1989.
Total Suspended Solids in the York River
- Gloucester Point and LE4.3 -
I 1 1—1 1 i 1 1 T
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984 198S 1986 1987 1988 1989
Figure VIM 5. Comparison of nearshore (Gloucester Point B^) and
mid-channel (LE4.3 —) surface total suspended solids concentrations
in the York River from 1984-1989.
Dissolved Inorganic Nitrogen in the York River
- Gloucester Point and LE4.3 -
0.6-,
i—'—i—'—i—'—i—'—r ......
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984
1985
1986
1987
1988
1989
Figure VIM 8. Comparison of nearshore (Gloucester Point«..«) and
mid-channel (LE4.3 —) surface dissolved inorganic nitrogen
concentrations in the York River from 1984-1989.
Total Suspended Solids in the York River
- Claybank and LE4.2 -
i i i » i—<—i—' i •—r—'—i—• i '—i—'—i • i '
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Dissolved Inorganic Nitrogren in the York River
- Claybank and LE4.2 -
0.6-,
I ' I ' I ' I ' I
Jun Dec Jun Deo Jun Dec Jun Dec Jun Dec Jun Dec
1984 1985 1986 1987 1988 1989
Figure V1M6. Comparison of nearshore (Claybank
-------
Nearshore and Mid-channel Water Quality Comparisons
solved inorganic nitrogen levels characteristic of these
regions during the warmer months were often below the
detection limits of the mid-channel monitoring program in
the York River. Therefore, the mid-channel data was
unsuitable for comparison to nearshore water quality.
Dissolved Inorganic Phosphorus
Dissolved inorganic phoshorus comparisons generally show
increasing divergence between mid-channel and nearshore
measurements with distance upriver as the absolute levels
of dissolved inorganic phosphorus increase (Figures VII-
20, VII-21, and VII-22). High detection limits at the mid-
channel monitoring stations, however, relative to theabsolute
concentrations present in the river, obscured the statistical
quantification of this trend. For examle, mid-channel data
for the Guinea Marsh and WE4.2 comparison were at the
detection limit for much of the time between 1984 and 1987
(Figure VII-20) and no direct growing season comparisons
could be made. Changes in analytical methodology at the
end of 1987 for this mid-channel station (WE4.2) resulted
in lower detection limits. These lower limits resulted in
significantly smaller reported mid-channel levels of dis-
solved inorganic phosphorus compared to the nearshore
site for the 1988 growing season (Table VII-7). During the
fall of each year, the levels at this mid-channel station were
above the detection limit (Figure Vii-20), permitting sta-
tistical analysis; no significant difference between the
midchannel and nearshore stations were found.
At the two upriver mid-channel stations (LE4.3 andLE4.2),
high detection limits obscured comparisons with the
nearshore data (Figures VII-21 and VII-22), except from
June through December each year. Similar patterns of
increasing levels during the fall and early winter are evi-
dent at both nearshore and mid-channel sites, as are gen-
erally increasing levels at each site with distance upriver.
The levels were not significantly different between the
respective nearshore and mid-channel stations during the
fall, but were significantly different during the summer
(Table VII-6). Because of the high detection limits at these
two mid-channel stations, growing season means could not
be statistically compared (Table VII-7), however concen-
trations appear higher at the nearshore stations, especially
from December through June (Figures VII-21 and VII-22).
Upper Potomac River
Water Temperature
Surface water temperatures were not available for the
nearshore areas of the Potomac, therefore, no comparisons
could be made.
Dissolved Inorganic Phosphorus in the York River
- Guinea Marsh and WE4.2 -
Jun Dec
1984
Jun Dec Jun Dec
1985 1986
Jun Dec Jun Dec Jun Dec
1987 1988 1989
Figure VII-20. Comparisons of nearshore (Guinea Marsh ^^ and mid-
channel (WE4.2 —) surface dissolved inorganic phosphorus
concentrations in the York River from 1984-1989.
Dissolved Inorganic Phosphorus in the York River
- Gloucester Point and LE4.3 -
f 0.09 3
10.08-j
(m-.
! 0.06'
J0.05-;
|O.U4^
]0.03-{
> 0.02 \
j °'01 •=
5
i ' i ' i • i • i • i ' i ' i ' i ' i ' i r
Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec Jun Dec
1984
1985 1986
1987
1988
1989
Figure VII-21. Comparisons of nearshore (Gloucester Point mam) and
mid-channel (LE4.3 —) surface dissolved inorganic phosphorus
concentrations in the York River from 1984-1989.
Dissolved Inorganic Phosphorus in the York River
- Claybank and LE4.2 -
o.09-
= 0.08.
1. 0.07 -i
I 0.06 -j
o0.05-i
§0.04.!
S0.03-J
| 0.02 -j
1 0.01 -I
Jun Dec Jun Dec Jun Dec
1984 1985 1986
Jun Dec Jun Dec Jun Dec
1987 1988 1989
Figure VII-22. Comparisons of nearshore (Claybank mm,) and mid-
channel (LE4.2 —) surface dissolved inorganic phosphorus
concentrations in the York River from 1984-1989.
149
CSC.SAV.12/92
-------
SAV Technical Synthesis
Table VII-8. Statistical comparisons of nearshore/mid-channel stations growing season medians in the upper Potomac River.
Stations Year KD TSS CHLA DIN DIP
Blossom Point/ 1985
XDA1177 1986
Wades Bay/ 1985
XDA4238 1986
Mouth Mattawoman/ 1985
XEA1840 1986
Gunston Cove/ 1985
XFB1433 1986
ElodcaCove/ 1985
XFB1433 1986
NS
ND
NS
NS
NS
NS •
NS
NS
NS
p<.006
NS
ND
NS
NS
NS
p=.02
NS
p<.05
NS
NS .
NS
ND
NS
NS
NS
p<.0001
NS ,
p<006
NS
p<.0035
NS
ND
ND
ND
NS
ND
NS
ND
NS
ND
NS
ND
ND
ND
NS
ND
NS .
ND
NS
ND
NS = not significant (p<.05)
ND » no data available
Light Attenuation Coefficient in the
Upper Potomac River
as.
XDAt177(C)
XEA1840(C)
0 GwlonC(N)
BJ XFB1433(C)
Q] EbtaCo.(N)
1965
1986
Figure VII-23. Comparisons of 1985 and 1986 growing season median
light attenuation coefficients for nearshore (N) and mid-channel (C)
monitoring stations in the upper Potomac River.
Total Suspended Solids in the
Upper Potomac River
50.
I!:
1985
1988
XDA1177tC)
XDM238(C)
XEA1E40(C)
GwslonC(N)
XFBJ433(C)
Bc*aCo.(N)
RgureVH-24. Comparisons of 1985 and 1986 growing season median
total suspended solids concentrations for nearshore (N) and mid-
channel (C) monitoring stations in the upper Potomac River.
150
CSC,$AV.12S2
Salinity
Surface salinities were not available for the nearshore areas
of the Potomac. Based upon existing segmentation schemes
and the geographical proximity of the nearshore/mid-chan-
nel station pairs, it was assumed that the salinities between
nearshore/mid-channel station pairs were similar.
Light Attenuation Coefficient
In 1985, median growing season light attenuation coeffi-
cient levels demonstrated little variability between sites.
Mid-channel sites, however, tended to have slightly higher
light attenuation levels than adjacent nearshore sites (Fig-
ure VII-23). None of the observed differences was found
to be significant (Table VII-8).
In 1986, median growing season light attenuation coeffi-
cient levels again exhibited only slight variability between
sites (Figure VII-23). One mid-channel station, XFB1433,
had statistically significant higher light attenuation coef-
ficient levels than nearshore station Elodea Cove (Table
VII-8). However, this same mid-channel station was also
compared to a second neighboring nearshore station,
(Gunston Cove) and the light attenuation coefficient levels
at these two stations did not differ significantly. This result
was somewhat surprising considering the extreme differ-
ences in chlorophyll a levels between these nearshore and
mid-channel sites but was well supported by the total
suspended solids values and exploratory graphical analy-
ses for the Potomac River.
-------
Nearshore and Mid-channel Water Quality Comparisons
Total Suspended Solids
In 1985, a majority of the nearshore sites had median total
suspended solid levels over the growing season that were
similar to adjacent mid-channel sites (Figure VII-24).
None of these comparisons were found to be statistically
significant (Table VII-8).
In 1986, the nearshore sites generally exhibited higher
median total suspended solids levels than adjacent mid-
channel sites (Figure VII-24). Two nearshore stations,
Mouth Mattawoman Creek and Gunston Cove, were found
to have significantly greater levels of total suspended
solids than the corresponding adjacent mid-channel sites
(Table VII-8). In general, total suspended solids levels
were more variable in 1986 than 1985. Some of these
differences may have been caused in part by large phyto-
plankton blooms that are characteristic of certain coves in
the Potomac River or by resuspension of sediments due to
wave action.
Chlorophyll a
The nearshore sites (Mouth Mattawoman, Gunston Cove,
and Elodea Cove), which are known to experience severe
phytoplankton blooms, exhibited high levels of chloro-
phyll a in 1985 when compared to all other stations in the
upper Potomac River (Figure VII-25). However, these
differences were not found to be statistically significant
(Table VII-8) and little variability was apparent between
the other stations.
In 1986, chlorophyll a levels were significantly higher at
the Mattawoman, Gunston Cove, and Elodea Cove sites
compared to corresponding adjacent mid-channel sites
(Table VII-8 and Figure VII-25). Chlorophyll a levels at
these three nearshore sites were generally observed to be
slightly higher in 1986 than in 1985-a year when no
significant differences were found. The other nearshore
station in the Potomac River (Wades Bay) was comparable
to adjacent mid-channel stations in 1986 (Table VII-8 and
Figure VII-25).
Dissolved Inorganic Nitrogen
Comparisons for dissolved inorganic nitrogen could only
be made for 1985 due to a lack of data at the nearshore sites
(Figure VII-26). In that year, no statistically significant
differences were found for dissolved inorganic nitrogen
between the nearshore and mid-channel areas that were
compared (Table VII-8). Exploratory graphical analyses
supported this finding that the nearshore and mid-channel
levels of dissolved inorganic nitrogen in the Potomac were
Chlorophyll a in the
Upper Potomac River
70
60:
]f «•=
H
I »•!
10-1
1985
HossonP(N)
XDAI177(C)
XDA4238IC)
XEA1S40(C)
HouttiMal(N)
GunstaC(N)
XFB!«3(C) •
BodsaCMN)
1986
Figure VII-25. Comparisons of 1985 and 1986 growing season median
chlorophyll a concentrations at nearshore (N) and mid-channel (C)
monitoring stations in the upper Potomac River.
Dissolved Inorganic Nitrogen in the
Upper Potomac River
STATION
Figure VII-26. Comparison of 1985 growing season median dissolved
inorganic nitrogen concentrations at nearshore (•) and mid-channel (ty
monitoring stations in the upper Potomac River.
Dissolved Inorganic Phosphorus in the
Upper Potomac River
STATION
Figure VII-27. Comparisons of 1985 growing season median dissolved
inorganic phosphorus concentrations for nearshore (•) and mid-channel
(&) monitoring stations in the upper Potomac River.
151
CSC.SAV.12/92
-------
SAV Technical Synthesis
comparable. Some slight differences did exist in dissolved
inorganic nitrogen levels between the stations, but these
were most likely due to the longitudinal water quality
gradient in the upper Potomac River (Figure VII-26).
Dissolved Inorganic Phosphorus
Comparisons for dissolved inorganic phosphorus could
only be made for 1985 due to a lack of data at the nearshore
sites. Analysis of this dataindicatedthatlevels of dissolved
inorganic phosphorus were very similar in adjacent
nearshore/mid-channel areas (Figure VII-27). No statis-
tically significant differences were found for dissolved
inorganic phosphorus between the nearshore and mid-
channel areas that were compared (Table VII-8). Explor-
atory graphical analyses supported the finding that nearshore
and mid-channel dissolved inorganic phosphorus levels in
the upper Potomac River were comparable. Some slight
differences did exist in dissolved inorganic phosphorus
levels, but these were most likely due to the longitudinal
water quality gradient in the upper Potomac River.
Choptank River
Water Temperature
Surface water temperatures were found to be nearly iden-
tical at adjacent nearshore and mid-channel stations, with
some variability most likely due to different sampling
times.
Salinity
Surface salinities were found to be nearly identical at
adjacent nearshore and mid-channel stations, with some
variability most likely due to different sampling times.
Light Attenuation Coefficient
In the Choptank River embayment, little variation in light
attenuation coefficient levels was apparent among all the
stations in all years (Figures VII-28 and VII-29). No
significant differences were detected between the near-
shore and mid-channel sites (Table VH-9).
In the Cambridge area, light attenuation coefficients were
similar between the nearshore and mid-channel sites al-
though the nearshore sites, Dickinson B ay and Bolingbroke
Creek, generally had the highest levels (Figure VII-30).
The elevated light attenuation coefficient levels at these
two sites, which were often significantly greater than the
light attenuation coefficient levels at other sites in the area
Light Attenuation Coefficient in the
Upper Choptank River
1. 6
-• i
—- OJ Q_ « li.
§ « i * ! •
• ••••I
I
STATION
Figure VII-28! Comparisons of 1986-1989 growing season median light
attenuation coefficients for the nearshore (•) and mid-channel (%)
monitoring stations in the Choptank River. This figure displays the
longitudinal light attenuation coefficient gradient present in the Choptank
River.
Light Attenuation Coefficient
Choptank River Embayment Area -
1 MEE2.1(C)
0 Buoy12A(C)
Cook's Cove (N)
Irishtek(N)
0 FoxholeCrak(N)
Figure VII-29. Comparisons of 1986-1989 growing season median light
attenuation coefficients for nearshore (N) and mid-channel (C) monitoring
stations in the Choptank River Embayment Area.
Light Attenuation Coefficient
- Choptank River Cambridge Area -
0 BuoyS (C)
i Horn Pt.(N)
gj DttJrai(N)
Figure VII-30. Comparisons of 1986-1989 growing season median light
attenuation coefficients for nearshore (N) and mid-channel (C) monitoring
stations in the Choptank River Cambridge Area.
152
-------
Nearshore and Mid-channel Water Quality Comparisons
Light Attenuation Coefficient
- Choptank River-Tuckahoe Area -
Total Suspended Solids
- Choptank River Cambridge Area -
1989
Figure Vll-31. Comparisons of 1987-1989 growing season median light
attenuation coefficients for nearshore (N) and mid-channel (C) monitoring
stations in the Choptank River Tuckahoe Area.
Figure VII-34. Comparisons of 1986-1989 growing season median total
suspended solids concentrations for nearshore (N) and mid-channel (C)
monitoring stations in the Choptank River Cambridge Area.
Total Suspended Solids in the
Choptank River
Total Suspended Solids
- Choptank River Tuckahoe Area -
STATION
Figure Vll-32. Comparisons of 1986-1989 growing season median total
suspended solids concentrations for nearshore (•) and mid-channel
(ty monitoring stations in the Choptank River. This figure displays the
longitudinal total suspended solids gradient present in the Choptank
River.
Figure VII-35. Comparisons of 1987-1989 growing season median total
suspended solids concentrations for nearshore (N) and mid-channel (C)
monitoring stations in the Choptank River Tuckahoe Area.
Total Suspended Solids
- Choptank River Embayment Area -
25
20-:
15-
10-j
5-
0
Chlorophyll a in the
Choptank River
til
1986
1967
1989
STATION
Figure VII-33. Comparisons of 1986-1989 growing season median total
suspended solids concentrations for nearshore (N) and mid-channel (C)'
monitoring stations in the Choptank River Embayment Area.
Figure VII-36. Comparisons of 1986-1989 growing season median
chlorophyll a concentrations for nearshore (•) and mid-channel (%)
monitoring stations in the Choptank River.
153
CSC.SAV.12/92
-------
SAV Technical Synthesis
Chlorophyll a
- Choptank River Embaymeni Area -
f1J
f 10
I1
i *
u
1 2
0
I
198
1987
B M£E2.1(0
0 Booy12A(0)
Q Co*sCovi(N)
0 MshCrwk(N)
0
1938
Figure Vll-37. Comparisons of 1986-1989 growing season median
chlorophyll a concentrations for nearshore (N)and mid-channel (C)
monitoring stations in the Choptank River Embayment Area.
Chlorophyll a
- Choptank River Cambridge Area -
MET5.2(C)
Buoy25(C)
HomPt(N)
DictJistn(N)
Q Bcin^icto(N)
1989
Figure VII-38. Comparisons of 1986-1989 growing season median
chlorophyll a concentrations for nearshore (N) and mid-channel (C)
monitoring stations in the Choptank River Cambridge Area.
Chlorophyll a
Choptank River Tuckahoe Area -
198!
1989
Figure VII-39. Comparisons of 1987-1989 growing season median
chlorophyll a concentrations for nearshore (N) and mid-channel (C)
monitoring stations in the Choptank River Tuckahoe Area.
(Table VH-10), were most likely related to the high total
suspended solids levels that were also found at these two
sites. Variability between the other stations in the area was
minimal.
In the Tuckahoe area, little variation was detected in light
attenuation coefficients between the nearshore and mid-
channel sites (Figure VII-31). In general, however, median
light attenuation coefficient levels were found to be slightly
higher at the mid-channel site. One significant difference
between mid-channel site MET5.1 and nearshore site Gilpin
Point was detected in 1989 (Table VII-11).
Total Suspended Solids
In the Choptank River embayment area, total suspended
solids concentrations were quite variable between stations
and between years, but no consistent pattern was apparent
between the nearshore and mid-channel areas (Figures VII-
32 and VH-33). MDE mid-channel station MEE2.1 was
found to have significantly greater total suspended solids
levels than HPEL mid-channel station Buoy 12A, possibly
indicating that the different sampling schedules and meth-
ods were biasing the results of these comparisons. How-
ever, few significant differences existed between the
mid-channel and nearshore stations during the comparison
period (Table VII-12). Variation among nearshore sites in
the embayment was comparable to the variation between
the nearshore and mid-channel sites.
In the Cambridge area of the Choptank River, nearshore
sites Dickinson Bay and Bolingbroke Creek exhibited
elevated total suspended solids levels in all years when
compared to all other stations in this area (Figures VII-32
and VII-34). Several of these differences were found to
be significant (Table VII-13). Total suspended solids
levels between the other stations in this area were generally
found to be comparable with little variability.
In the Tuckahoe area of the Choptank, total suspended
solids levels showed little variation between the mid-
channel and nearshore sites (Figures VII-32 and VII-35).
Only one statistically significant difference, between mid-
channel station MET5.1 and nearshore station Tuckahoe
Creek, was detected (Table VII-14).
Chlorophyll a
The 1986 chlorophyll a levels in the embayment area were
generally (but not significantly) lower in the mid-channel
relative to the nearshore (Figures VII-36 and VII-37, and
Table VII-15). In 1987 and 1988, the reverse was observed
154
CSCSAV.1292
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Nearshore and Mid-channel Water Quality Comparisons
Dissolved Inorganic Nitrogen
in the Choptank River
0-6
0.4-
• I i
= J. s
a.
I
Dissolved Inorganic Nitrogen
- Choptank River Tuckahoe Area -
STATION
Figure VII-40. Comparisons of 1986-1989 growing season median
dissolved inorganic nitrogen concentrations for the nearshore (•) and
mid-channel (%) monitoring stations in the Choptank River. This figure
displays the longitudinal dissolved inorganic nitrogen gradient present
in the Choptank River.
Figure VII-43. Comparison of 1987-1989 growing season median
dissolved inorganic nitrogen concentrations for the nearshore (N) and
mid-channel (C) monitoring stations in the Choptank River Tuckahoe
Area.
Dissolved Inorganic Nitrogen
- Choptank River Embayment Area -
| MEE2.1(C)
\2 Buoyt2A(C)
H Cook's Cow (N)
gj Iristi Creek (H
g Ctop«l Creek (N)
0 FoxtoteCrwk(tl)
Dissolved Inorganic Phosphorus
in the Choptank River
| ""
0.04-
0.03-
0.02-
0.01-
S I
1966
STATION
Figure VII-41. Comparisons of 1986-1989 growing season median
dissolved inorganic nitrogen concentrations at nearshore (N) and mid-
channel (C) monitoring stations in the Choptank River Embayment Area,
Figure VII-44. Comparisons of 1986-1989 growing season median
dissolved inorganic phosphorus concentrations for the nearshore (•)
and mid-channel (22) monitoring stations in the Choptank River. This
figure displays the longitudinal dissolved inorganic phosphorus gradient
present in the Choptank River.
Dissolved Inorganic Nitrogen
Choptank River Cambridge Area -
HETSi(C)
Buoy25(C)
Horn PL (N)
Dickinson (N)
Bolngbrck9(N)
1989
Figure VII-42. Comparison of 1986-1989 growing season median
dissolved inorganic nitrogen concentrations at nearshore (N) and mid-
channel (C) stations in the Choptank River Cambridge Area.
Dissolved Inorganic Phosphorus
Choptank River Embayment Area -
1 MEE2.1(C)
0 B«oy12A(C)
I (M'sCtra(U)
^ liish Creek (N)
0 Foxhole Creek (N)'
Figure VII-45. Comparisons of 1986-1989 growing season median
dissolved inorganic phosphorus concentrations for the nearshore (N)
and mid-channel (C) monitoring stations in the Choptank River Embayment
Area.
155
CSC.SAV.12/92
-------
SAV Technical Synthesis
Dissolved Inorganic Phosphorus
Choptank River Cambridge Area -
i
191$
1987
1988
1939
i MET5i(Q
Q BuoyS (C)
El HomPt(N)
Figure VIMS. Comparisons of 1986-1989 growing season median
dissolved inorganic phosphorus concentrations for the nearshore (N)
and mid-channel (C) monitoring stations in the Choptank River Cambridge
Area.
Dissolved Inorganic Phosphorus
- Choptank River Tuckahoe Area -
Figure VII-47. Comparisons of 1987-1989 growing season median
dissolved inorganic phosphorus concentrations for nearshore (N) and
mid-channel (C) monitoring stations in the Choptank River Tuckahoe
Area.
with chlorophyll a levels often significantly greater in the
mid-channel relative to nearshore. No consistent pattern
of variation was apparent in 1989, and no significant
differences were detected between the mid-channel and
nearshore sites.
In the Cambridge and Tuckahoe areas, no consistent varia-
tion was detected between the nearshore and mid-channel
sites (Figures VII-36, VII-38, and VII-39). Only three
significant differences, all occurring in 1987, were de-
tected between the mid-channel and nearshore sites (Tables
VII-16 and VH-17). Two of the differences were in the
Tuckahoe area where the two nearshore sites seemed to
exhibit unusually low chlorophyll a levels in 1987 when
compared to other years.
Dissolved Inorganic Nitrogen
In the Choptank embayment, little consistent variation was
detected between the mid-channel and nearshore sites
(Figures VII-40 and VII-41). A few statistically signifi-
cant differences were found for dissolved inorganic nitro-
gen between the nearshore and mid-channel sites in the
embayment, but these differences were not consistent from
year to year (Table VII-18). Exploratory graphical analy-
ses revealed that similar differences were also present
among the nearshore stations although none of these dif-
ferences were significant (Figure VII-41 and Table VII-
18).
In the Cambridge area, dissolved inorganic nitrogen levels
were highest at the mid-channel stations relative to the
nearshore stations in each year (Figures VII-40 and VII-
42). Some statistically significant differences were de-
tected between the nearshore and mid-channel stations
although these differences were not consistent from year
to year (Table VII-19). Similar significant differences
were detected among the nearshore sites in 1988. It is
possible that effluent from the Cambridge wastewater
treatment plant was influencing these observations by
elevating dissolved inorganic nitrogen concentrations in
mid-channel areas.
In the Tuckahoe area, dissolved inorganic nitrogen levels
were found to be greater at mid-channel station MET5.1
relative to the two nearshore stations in each year (Figure
VII-43). None of these observed differences, however,
were statistically significant (Table VII-20).
Dissolved Inorganic Phosphorus
Only one statistically significant difference between mid-
channel and nearshore levels of dissolved inorganic phos-
phorus was detected in the Choptank River (Tables VII-21
through VII-23). Exploratory graphical analyses for this
river support the statistical findings, indicating little dif-
ference between the nearshore and mid-channel sites (Fig-
ures VII-44 through VII-47). Some problems were
encountered with inadequate detection limits at the MDE
sites, preventing the use of these data in the embayment
and Cambridge areas.
Upper Chesapeake Bay
Water Temperature
Surface water temperatures were found to be nearly iden-
tical at adjacent nearshore and mid-channel stations, with
156
CSOSAV.12M
-------
Nearshore and Mid-channel Water Quality Comparisons
Table VII-9. Statistical comparisons of yearly growing season nearshore/mid-channel station data for light attenuation—Choptank River
Embayment Area.
Irish Creek Chapel Creek Foxhole Creek
NS(1986-89) NS(1986-89) NS(1986-89)
NS(1988-89) NS(1988-89) NS(1988-89)
NS(1987-89) NS(1987-89)
NS(1986-89)
MEE2.1
Buoy 12A
Cook's Cove
Irish Creek
Buoy 12A
NS(1988-89)
**##
****
****
Cook's Cove
NS(1987-89)
NS(1988-89)
****
#***
Chapel Creek ****
NS = not significant (p>.05)
ND = no data available
*#**
****
****
****
NS(1987-89)
NS(1986-89)
NS(1986-87,89)
Table VII-10. Statistical comparisons of yearly growing season nearshore/mid-channel station data for light attenuation-Choptank River
Cambridge Area.
MET5.2
Buoy 25
Horn Point
Buoy 25
NS(1988)
p<.0001(1989)
*#**
****
Horn Point
NS(1987-89)
NS(1988-89)
****
Dickinson Bay
NS(1987-89)
p<.005(1986)
NS(1988)
p<.02(1989)
NS(1987-88)
p<.025(1989)
Bolingbroke O
NS(1987,89)
p<01(1986,88)
p<.01(1988-89)
NS(1987,89)
p<.03(1988)
Dickinson Bay
**#*
NS = not significant (p>.05)
ND = no data available
****
****
NS(1986-89)
Table VIM 1. Statistical comparisons of yearly growing season nearshore/mid-channel station data for light attenuation—Choptank River
Tuckahoe Area.
MET5.1
Gilpin Point
NS = not significant (p>.05)
ND = no data available
Gilpin Point
NS(1986-88)
p<.025(1989)
****
Tuckahoe Creek
NS(1987-89)
NS(1987-89)
157
CSC.SAV.12/92
-------
SAV Technical Synthesis
Table VII-12. Statistical comparisons of yearly growing season nearshore/mid-channel station data for total suspended solids—Choptank
River Embayment Area.
Buoy 12A
Cook's Cove Irish Creek Chapel Creek Foxhole Creek
MEE2.1
Buoy 12A
Cook's Cove
Irish Creek
Chapel Creek
p<006(1988-89)
****
****
****
****
NS(1987,89)
p<05(1988)
NS(1988-89)
****
****
**#*
NS(1986-88)
p<.01(1989)
NS(1989)
p<.015(1988)
NS(1987-89)
****
****
NS(1 986-87)
p<.03(1988-89)
NS(1988-89)
NS(1987-89)
NS(1986,87,89)
p<.015(1988)
****
NS(1986-89)
NS(1988-89)
NS(1987-89)
NS(1986-89)
NS(86,87,89)
NS = not significant (JB>.05)
ND = no data available
Table V1I-13. Statistical comparisons of yearly growing season nearshore/mid-channel station data for total suspended solids—Choptank
River Cambridge Area.
Buoy 25
Horn Point
Dickinson Bay
Bolingbroke Creek
MET5.2
Buoy 25
Horn Point
Dickinson Bay
NS(1988)
p<0003(1989)
****
****
****
NS(1987-88)
p<01(1989)
NS(1988-89)
****
****
NS(1 988-89)
P<.05(1986-87)
NS(1988)
p<.025(1989)
NS(1987-88)
p<04(1989)
****
NS(1989)
p<.05(1986-88)
p<.014(1988-89)
NS(1987)
p<03(1988-89)
NS(1987-89)
p<.01(1986)
NS s not significant (p>.05)
ND = no data available
Table Vll-14. Statistical comparisons of yearly growing season nearshore/mid-channel station data for total suspended solids—Choptank
River Tuckahoe Area.
MET5.1
Gilpin Point
Gilpin Point
NS(1987-89)
Tuckahoe Creek
NS(1987-88)
p<014(1989)
NS(1987-89)
NS s not significant (p>.05)
ND = no data available
158
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-------
Nearshore and Mid-channel Water Quality Comparisons
Table VII-15. Statistical comparisons of yearly growing season nearshore/mid-channel station data for chlorophyll a—Choptank River
Embayment Area.
Buoy 12A
Cook's Cove
Irish Creek Chapel Creek Foxhole Creek
MEE2.1 NS(1988-89)
Buoy 12A ****
Cook's Cove ****
Irish Creek ****
Chapel Creek ****
NS = not significant (p>.05)
ND = no data available
NS(1989)
p<.0025(1987-88)
NS(1989)
p<015(1988)
#*#*
#***
****
NS(1986,89)
p<.025(1987-88)
NS(1989)
p<.05(1988)
NS(1987-89)
****
*#**
NS(1986,89)
p<.005(1987-88)
NS(1989)
p<.01(1988)
NS(1987-89)
NS(1986-89)
****
NS(1986,89)
p<.017(1987-88)
NS(1989)
p<.019(1988)
NS(1987-89)
NS(1986-89)
NS(1986-89)
p<.05(1988)
Table VII-16. Statistical comparisons of yearly growing season nearshore/mid-channel station data for chlorophyll a—Choptank River
Cambridge Area.
Buoy 25
Horn Point
Dickinson Bay
Bolingbroke Creek
MET5.2
Buoy 25
Horn Point
Dickinson Bay
NS(1988-89)
NS(1986,88,89)
p<.05(1987)
NS(1988-89)
****
**=f=*
NS(1986-89)
NS(1988-89)
NS(1986-89)
****
NS(1 986-89)
NS(1988-89)
NS(1986-89)
NS(1986-89)
NS = not significant (p>.05)
ND = no data available
Table VII-17. Statistical comparisons of yearly growing season nearshore/mid-channel station data for chlorophyll a—Choptank River
Tuckahoe Area.
MET5.1
Gilpin Point
NS = not significant (p>.05)
ND = no data available
Gilpin Point
NS(1986,88,89)
p<.0001(1987)
****
Tuckahoe Creek
NS(1988-89)
p<.0001(1987)
NS(1987-89)
159
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-------
SAV Technical Synthesis
Table VIM8. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic nitrogen-
Choptank River Embayment Area.
Buoy 12A
Cook's Cove Irish Creek Chapel Creek Foxhole Creek
MEE2.1 NS(1988-89)
Buoy 12A ****
Cook's Cove ****
Irish Creek ****
Chapel Creek ****
NS « not significant (p>.05)
ND = no data available
NS(1987-89)
NS(1988-89)
#*#*
****
NS(1987,89) NS(1986-89)
p<.05(1986,88)
NS(1988-89) NS(1988-89)
NS(1987-89) NS(1987-89)
**** NS(1986-89)
****
##*#
NSU987-88)
p<.05(1986,89)
NS(1988)
p<.05(1989)
NS(1987-89)
NS(1986-89)
NS(1986-89)
Table VII-19. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic nitrogen-
Choptank River Cambridge Area.
Buoy 25
Horn Point
Dickinson Bay
Bolingbroke Creek
MET5.2
Buoy 25
Horn Point
NS(1988-89)
****
****
Dickinson Bay ****
NS * not significant (p>.05)
ND = no data available
NSU987-88)
p<025(1989)
NS(1988-89)
****
NS(1989)
, p<05(1986-88)
NS(1988-89)
NS(1987,89)
p<05(1988)
NS(1986)
p<.05(1987-89)
NS(1988)
p<01(1989)
NS(1987,89)
p<.03(1988)
****
****
NS(1986-89)
Table Vll-20. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic nitrogen-
Choptank River Tuckahoe Area.
MET5.1
Gilpin Point
NS = not significant (p>.05)
ND = no data available
Gilpin Point
NS(1987-89)
Tuckahoe Creek
NS(1987-89)
NS(1987-89)
160
CCCSAV.Ii'K
-------
Nearshore and Mid-channel Water Quality Comparisons
Table VII-21. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic phosphorus—
Choptank River Embayment Area.
Buoy 12A
Cook's Cove
Irish Creek
Chapel Creek
Buoy 12A
****
****
****
****
Cook's Cove
NS(1988-89)
****
****
****
Irish Creek
NS(1988-89)
NS(1987-89)
****
****
Chapel Creek
NS(1988-89)
NS(1987-89)
NS(1986-89)
****
Foxhole Creek
NS(1988-89)
NS(1987-89)
NS(1986-89)
NS(1986-89)
NS = not significant (p>.05)
ND = no data available
Table VII-22. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic phosphorus—
Choptank River Cambridge Area.
Buoy 25
Horn Point
Dickinson Bay
Buoy 25
****
****
Horn Point
NS(1988-89)
****
****
Dickinson Bay
NS(1988-89)
NS(1987-89)
****
Bolingbroke Creek
NS(1988-89)
NS(1987-89)
NS(1988-89)
NS = not significant (p>.05)
ND = no data available
Table VII-23. Statistical comparisons of yearly growing season nearshore/mid-channel station data for dissolved inorganic phosphorus—
Choptank River Tuckahoe Area.
MET5.1
Gilpin Point
NS = not significant (p>.05)
ND = no data available
Gilpin Point
NS(1987-89)
****
Tuckahoe Creek
NS(1988-89)
p<0.02 (1987)
NS(1987-89)
161
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SAV Technical Synthesis
Table VII-24. Statistical comparisons of yearly growing season nearshore/mid-channel station data for the upper Chesapeake Bay.
Stations
Georgetown/MET3. 1
Piney (in)/Piney (out)
Elk (in)/Elk (out)
Elk (in)/MET2.3
Havre D/Susquehanna
Havre D/MCB1.1
Havre D/Fishing (out)
Havre D/Center Bay
Fishing (in)/Susquehanna
Fishing (in)/MCBl.l
Fishing (in)/Fishing (out)
Fishing (in)/Center Bay
NS = not significant fp>.05)
ND = no data available
** Susquchanna = Log Pond
** Havre D = Outfall
Year
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
1988
1989
Kd
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
CHLA
ND
NS
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
TSS
ND
NS
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
DIN
ND
NS
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
DIP
ND
NS
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
some variability most likely due to different sampling
times.
Salinity
Surface salinities were not available for the stations moni-
tored by HCC in the upper Chesapeake Bay. Based upon
existing segmentation schemes and the geographical prox-
imity of the nearshore/mid-channel station pairs, it was
assumed that the salinities between the nearshore/mid-
channel station pairs were similar.
Light Attenuation Coefficient
No significant differences in light attenuation coefficient
levels were detected between nearshore and mid-channel
stations in the upper Chesapeake Bay (Table VII-24).
Light levels were found to be nearly identical between
adjacent nearshore and mid-channel stations in the two
years that data were available (Figures VII-48 through VII-
51). This result suggests that light levels do not vary
significantly between nearshore and mid-channel sites in
the upper Chesapeake Bay.
Total Suspended Solids
In the upper Chesapeake Bay, nearshore total suspended
solids data were collected for only one year at a single
location in the Sassafras River (Georgetown). Compari-
sons between the nearshore station and an adjacent mid-
channel station revealed no significant differences in the
162
-------
Nearshore and Mid-channel Water Quality Comparisons
levels of total suspended solids between the two stations
(Figure VII-52 and Table VII-24).
Chlorophyll a
Nearshore chlorophyll a data for the upper Chesapeake
Bay were collected for only one year at a single location
in the Sassafras River (Georgetown). Comparisons be-
tween the nearshore station and an adjacent mid-channel
station revealed no statistically significant differences in
chlorophyll a levels between the two stations (Figure VII-
53 and Table VII-24).
Dissolved Inorganic Nitrogen
Dissolved inorganic nitrogen data were only available for
one yearatonelocationinthenearshorestation (Georgetown)
due to analytical problems. Comparisons between the
nearshore and mid-channel stations located in the Sassa-
fras River revealed no significant difference in the levels
of dissolved inorganic nitrogen between the two stations
(Figure VII-54 and Table VII-24).
Dissolved Inorganic Phosphorus
In the upper Bay, nearshore dissolved inorganic phospho-
rus data were only available for one year at one location
(Georgetown) because of analytical problems. Compari-
sons between the nearshore station and an adjacent mid-
channel station located in the Sassafras revealed no
significant difference in the levels of dissolved inorganic
phosphorus between the two stations (Figure VII-55 and
Table VII-24).
Discussion •
Light Attenuation Coefficient
Comparison of Secchi depths and photosynthetically ac-
tive radiation (PAR) attenuation using light sensors corre-
lated with recent research which indicated that measurements
of transparency by Secchi disk are as accurate and precise
as estimates of light attenuation calculated from light
sensor readings in the sea (Megard and Berman 1989).
Based upon these results, Secchi depth readings provided
an acceptable substitute for light sensor readings in Chesa-
peake Bay for the purposes of this application, as long as
water depths exceeded Secchi depths.
Overall, comparisons of mid-channel and nearshore light
attenuation coefficients yielded the closest agreement of
all variables examined (Figure VII-56). Relative to the
Light Attenuation Coefficient
- Sassafras River -
1989
Figure VII-48. Comparison of 1988-1989 growing season median light
attenuation coefficientsfornearshore (•) and mid-channel (%) monitoring
stations in the Sassafras River.
Light Attenuation Coefficient
- Susquehanna Flats -
1988
1989
Figure VII-49. Comparisons of 1988-1989 growing season median light
attenuation coefficients at nearshore (•) and mid-channel (
-------
SAV Technical Synthesis
Light Attenuation Coefficient
- Upper Elk River
Dissolved Inorganic Nitrogen
- Sassafras River
r-0.25-
1988
1989
Figure VH-51. Comparisons of 1988-1989 growing season median light
attenuation coefficients at nearshore (•) and mid-channel (22) monitoring
stations in the upper Elk River.
Total Suspended Solids
- Sassafras River
0.2-
0.15-
o.H
> 0.05-
o
Georgetown MET3.1
Figure Vll-54. Comparisons of 1989 growing season median dissolved
inorganic nitrogen concentrations for nearshore (•) and mid-channel
(ty monitoring stations in the Sassafras River.
Dissolved Inorganic Phosphorus
- Sassafras River
Georgetown MET3.1
Figure VII-52. Comparisons of 1989 growing season median total
suspended solids concentrations for nearshore (•) and mid-channel
(%) monitoring stations in the Sassafras River.
0.008 •
Chlorophyll a
- Sassafras River
100-=
» 0.007 H
1 0.006 H
Q.
1 0.005-
| 0.004-
10.003-
| 0.002H
•g 0.001 H
•2 n.
a u
Georgetown MET3.1
Figure VII-55. Comparisons of 1989 growing season median dissolved
inorganic phosphorus concentrations for nearshore (•) and mid-channel
(32) monitoring stations in the Sassafras River.
Georgetown MET3.1
Figure VII-53. Comparisons of 1989 growing season median chlorophyll
a concentrations for nearshore (•) and mid-channel (22) monitoring
stations in the Sassafras River.
164
CSOSAV.12&
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Nearshore and Mid-channel Water Quality Comparisons
Nearshore/Mid-Channel Light Attenuation Coefficient
01234567
Mid-Channel Light Attenuation Coefficient (m -1)
Figure VII-56. Comparisons of paired nearshore and mid-channel growing season median light attenuation coefficient data from the York River (O), upper
Potomac River (A), Choptank River (D), and upper Chesapeake Bay (O).
Nearshore/Mid-Channel Total Suspended Solids
50-
*§>
en 40-
TJ
•S 30H
g
Q.
(0
s>
10-
2
a
o>
0 10 20 30 40 50
Mid-Channel Total Suspended Solids (mg/l)
Figure VII-57. Comparisons of paired nearshore and mid-channel growing season median total suspended solids data from the York River (O),
upper Potomac River (A), Choptank River (D), and upper Chesapeake Bay (O).
165
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SAV Technical Synthesis
Nearshore/Mid-Channel Chlorophyll a
10 20 30 40 50 60 70 80 90 100
Mid-Channel Chlorophyll a (\ig/\)
Figure VH-58. Comparisons of paired nearshore and mid-channel growing season median chlorophyll a data from the York River (O), upper Potomac
River (A), Choptank River (D), and upper Chesapeake Bay (O),
Nearshore/Mid-Channel Chlorophyll a
Mid-Channel Chlorophyll a
Rgure VII-59. Comparisons of paired nearshore and mid-channel growing season median chlorophyll a data from the York River (O), upper Potomac
River (A), Choptank River (D), and upper Chesapeake Bay (O). Expanded scale from Figure VII-58.
166
CSCSAV.12/92
-------
Nearshore and Mid-channel Water Quality Comparisons
Nearshore/Mid-Channel Dissolved Inorganic Nitrogen
0 0.5 1 1.5 2
Mid-Channel Dissolved Inorganic Nitrogen (mg/l)
Figure VII-60. Comparisons of paired nearshore and mid-channel growing season median dissolved inorganic nitrogen data from the York River (O),
upper Potomac River (A), Choptank River (a), and upper Chesapeake Bay (O).
light attenuation coefficient SAV habitat requirement for
one meter restoration, data from adjacent nearshore and
mid-channel stations yielded identical classifications of
meeting/not meeting the habitat requirements 87.5% of the
time (Table VII-25). As with total suspended solids,
considerable variability over the growing season was
observed in the discrete measures of light attenuation
reported here. This is not surprising considering the
number of factors, both physical and biological, that can
influence the concentration of particles in the water column
and, therefore, the attenuation of light. However, given the
constraints of the sampling it appears that mid-channel
Secchi depth observations provide an adequate model of
nearshore conditions when measured over a seasonal time
frame.
Total Suspended Solids
Total suspended solids were characterized by considerable
variability within the growing season in both the nearshore
and mid-channel areas. Because of the high variability and
small sample populations, differences between sites may
have been difficult to detect. Relative to the total sus-
pended solids SAV habitat requirements for one meter
restoration, data from adjacent nearshore and mid-channel
stations yielded identical classifications 65.7% of the time
(Table VII-25). Overall, no strong bias between nearshore
and mid-channel sites was observed (Figure VII-57). Where
statistically significant differences were found they gen-
erally indicated higher levels in nearshore locations. This
suggests possible inputs due to run-off or resuspension due
to wave action in certain shallow areas. Some occurrences
of higher nearshore total suspended solids levels in the
Potomac may have been due to increased organic particu-
late matter such as phytoplankton (see chlorophyll a sec-
tion below). Particulates contribute to total suspended
solids and have the ability to attenuate sunlight before it
reaches SAV.
Chlorophyll a
Differences in chlorophyll a concentrations between mid-
channel and nearshore sites were most pronounced in
embayments and coves of the Potomac River (Figures VII-
58 and VII-59). It is possible that differing residence times
or entrapment of wind-blown surface films may play an
important role in causing differences in phytoplankton
biomass between mid-channel and nearshore sites in these
areas.
In most of the sites studied, chlorophyll a levels were
comparable between nearshore and mid-channel sites (Fig-
ures VII-58 and VII-59). Relative to the chlorophyll a SAV
habitat requirements for one meter restoration, data from
adjacent nearshore and mid-channel stations yielded iden-
tical classifications 81.2% of the time (Table VII-25).
167
CSC.SAV.12/92
-------
SAV Technical Synthesis
Therefore, mid-channel monitoring appears to provide a
suitable measure of chlorophyll a in nearshore environ-
ments under most circumstances. However, phytoplank-
ton generally has patchy distributions. This natural variability
can cause differences between nearshore and mid-channel
sites as well as between different nearshore sites.
Dissolved Inorganic Nitrogen
The general lackofsignificantdifferences observed among
the paired stations for dissolved inorganic nitrogen in this
study suggests that mid-channel monitoring may be useful
for assessing the levels in the nearshore where the data are
summarized over growing seasons (Figures VII-60 and
VII-61). Relative to the dissolved inorganic nitrogen SAV
habitat requirements for one meter restoration, data from
adjacent nearshore and mid-channel stations yielded iden-
tical classifications 82.8% of the time (Table VII-25). The
fact that there were few significant differences in the paired
data sets, however, does not necessarily demonstrate that
dissolved inorganic nitrogen levels in mid-channel and
nearshore regions are generally the same.
Over the SAV growing season, dissolved inorganic nitro-
gen levels typically range from very high in spring to very
low at the end of summer, especially in mesohaline areas.
This wide range contributes to low power in the statistical
tests, making differences between sites difficult to identify
with a seasonal aggregation of data. This large range of
dissolved inorganic nitrogen levels during the growing
season likewise contributes to uncertainty in the habitat
requirements themselves. Localized differences were found
at several locations, including the embayment and Cam-
bridge areas on the Choptank River. These differences
may reflect point source inputs of dissolved inorganic
nitrogen.
Dissolved Inorganic Phosphorus
The comparison of dissolved inorganic phosphorus levels
in mid-channel and nearshore areas was limited in several
regions by problems with high detection limits for the mid-
channel data. Where this was not a problem, the results
suggest that levels in mid-channel and nearshore areas are
comparable with few statistically significant differences or
consistent biases (Figure VII-62). Relative to the dissolved
inorganic phosphorus SAV habitat requirements for one
meter restoration, data from adjacent nearshore and mid-
channel stations yielded identical classifications 75% of
the time (Table VII-25).
Other Reported Results
Results from a statistical comparison of mainstem near-
shore and mid-channel water quality data are summarized
here (Chesapeake Bay Program 1992) to demonstrate that
the findings from the tributary study areas presented in this
report can be applied to monitoring data from the mainstem
Bay. These mainstem nearshore/mid-channel compari-
sons used the same exploratory data analysis and statistical
analysis techniques employed by Bieber and Moore in the
tributary studies reported in this chapter.
Table VII-25. Classification rate of mid-channel relative to nearshore stations using SAV habitat requirements for one meter restoration.
Low
Light attenuation coefficient 3 (7.5%)
Total suspended solids 10 (28.6%)
Chlorophyll a 3 (9.4%)
Dissolved inorganic nitrogen 0 (0%)
Dissolved inorganic phosphorus 4 (16.7%)
TOTAL
20 (12.2%)
Same
35 (87.5%)
23 (65.7%)
26 (81.2%)
24 (82.8%)
18 (75.0%)
126 (77.3%)
High
2 (5%)
2 (5.7%)
3 (9.4%)
5 (17.2%)
2 (8.3%)
17 (10.4%)
Total
40 (100%)
35 (100%)
32 (100%)
29 (100%)
24 (100%)
163 (100%)
Low
Nearshore does not meet habitat requirements for one meter restoration; mid-channel meets habitat requirements for one
meter restoration.
Same = Both nearshore and mid-channel do or do not meet habitat requirements for one meter restoration.
High — Nearshore meets habitat requirements for one meter restoration; mid-channel does not meet habitat requirements for one
meter restoration.
168
CSOSAV.12&2
-------
Nearshore and Mid-channel Water Quality Comparisons
Nearshore/Mid-Channel Dissolved Inorganic Nitrogen
0)0.8-
2
.*;
0.6-
co
2»
o
g> 0.4-
W
5
S>
o
I
co
Q>
0.2-
on
0 0.2 0.4 0.6 0.8 1
Mid-Channel Dissolved Inorganic Nitrogen (mg/l)
Figure VII-61. Comparisons of paired nearshore and mid-channel growing season median dissolved inorganic nitrogen data from the York River (O),
upper Potomac River (A), Choptank River (n), and upper Chesapeake Bay (O). Expanded scale from Figure VII-60.
Nearshore/Mid-Channel Dissolved Inorganic Phosphorus
0.08-
(0
3
O
•§. 0.06-
1
Q.
0
0.04 -I
o
1
0.02H
2
o
1
o
o
0 0.02 0.04 0.06 0.08
Mid-Channel Dissolved Inorganic Phosphorus (mg/l)
Figure Vli-62. Comparisons of paired nearshore and mid-channel growing season median dissolved inorganic phosphorus data from the York River (O),
upper Potomac River (A), Choptank River (n), and upper Chesapeake Bay (O).
169
CSC.SAV.12/92
-------
SAV Technical Synthesis
Comparisons used April-October seasonal medians from
the surface layer for all five SAV habitat requirements
(Secchi depth as a substitute for light attenuation coeffi-
cient, total suspended solids, chlorophyll a, dissolved in-
organic nitrogen, and dissolved inorganic phosphorus).
The nearshore and mid-channel data compared were from
seven east-west monitoring station transects located in the
middle Chesapeake Bay. There were no statistically sig-
nificant differences between mid-channel and eastern sta-
tions for any of the listed parameters in any transects. For
the mid-channel and western station comparisons, there
were statistically significant differences (p < 0.01) for four
of these five parameters (all but dissolved inorganic nitro-
gen) in three of the six transects studied (CB4.1 through
CB4.3).
The results still support using mid-channel data to charac-
terize water quality in nearshore habitats for two reasons.
First, the western stations in two of the three transects
involved (CB4.2W and CB4.3E) do not characterize po-
tential SAV habitat (Appendix A, Tables A-l and A-2).
Most of the potential SAV habitat in this area of the Bay
is on the Eastern Shore. Second, the difference between
seasonal median values at the western and central stations
were small in all three transects. For all four parameters,
the median difference over six years between west and
center April-October medians was near the analytical pre-
cision for that parameter: dissolved inorganic phosphorus
= 0.0012-0.0014 mg/1, chlorophyll a = 2.4-3.3 ug/1, total
suspended solids = 1.3-1.8 mg/1, and Secchi depth = 0.2-
0.5 m.
Findings
Results from this study indicate that data collected in the
mid-channel of Chesapeake Bay tributaries may be suc-
cessfully used to characterize seasonal levels of the inves-
tigated water quality variables in adjacent nearshore areas.
Statistically significant differences do exist in some cases
between the nearshore and mid-channel stations, but in
most instances, consistent biases over the different years
and sites were not evident. Where data were available for
several nearshore sites in a particular region, the variability
among these sites was comparable to the variability be-
tween the nearshore and mid-channel sites. Where data
were not subject to error induced by different sampling
times and analytical methods, few significant differences
were found.
While the results of this study do support the use of mid-
channel data to characterize nearshore areas over seasonal
time frames, they are not meant to imply a predictive
relationship between nearshore and midichannel observa-
tions. Rather, it is proposed that seasonal aggregations of
mid-channel water quality data can provide reliable esti-
mates of nearshore water quality conditions, at least for
those variables presented here (light attenuation coeffi-
cient, total suspended solids, chlorophyll a, dissolved in-
organic nitrogen, and dissolved inorganic phosphorus).
Although nearshore observations of the investigated water
quality variables do tend to correspond closely to obser-
vations in adjacent mid-channel areas, no predictive rela-
tionships were investigated.
This study has answered many of the questions about the
comparability of nearshore and mid-channel water quality
as they relate to SAV growth requirements. Additional
analyses would be required to assess the ability of mid-
channel data to characterize nearshore locations for other
variables and/or different time and space scales. If the need
for these comparisons is great in the future, then it may be
desirable to initiate specific studies that are designed to
better control sources of variability that were encountered
in this study.
170
-------
Chapter VHI
Future Needs
he submerged aquatic vegetation (SAV) habitat
requirements presented in this report were gener-
ated from a variety of studies by different inves-
tigators. They represent minimal water quality conditions
that simply support SAV survival, and do not provide
criteria for species diversity, biomass, or functional value.
As such, the habitat requirements could be further devel-
oped to incorporate these other aspects of SAV distribution.
Future research could also: a) define the time scales of SAV
responses; b) further quantify the components of light
attenuation; and, c) employ SAV transplants to further test
SAV survival/light attenuation/water depth relationships.
Future research efforts to specifically address water quality
effects on SAV should include laboratory, mesocosm, field
and modeling efforts, and a coordination of the research
efforts to insure consistency of sampling design, analytical
methodology, and data analyses. While the empirical
results used here are good predictors of SAV survival in
Chesapeake Bay, it is unknown how effective they may be
in other coastal bays. It would be of interest to test the
Chesapeake Bay SAV habitat requirements in other sys-
tems with the goal of developing more generic SAV habitat
requirements that could be used in other locations. Both the
actual habitat requirements and the habitat requirement
approach can be used in this context as models for future
studies.
The use of SAV distributions as integrating "light meters"
over the appropriate temporal and spatial scales could be
further refined. The lag time, or delay in SAV response, to
changes in ambient light regimes needs to be established in
order to better interpret SAV distributional data with regard
to water quality. An ongoing SAV trends analysis will
address the time lag between water quality improvements
and SAV resurgences in some areas of the Bay. Some SAV
species can withstand relatively long periods of low light
availability before exhibiting a growth or survival response,
so a time scale of SAV response would be helpful in
applying habitat requirements. In addition, the rates of
colonization of SAV into unvegetated areas need to be
quantified so that SAV resurgences can be predicted from
proposed water quality improvements. A model of SAV
growth that incorporates seasonal growth responses to
changes in light attenuation would be useful in this context.
Since the timing and duration of low light events (e.g.,
resuspension, high runoff periods) will affect SAV re-
sponses, an understanding of seasonal dynamics of growth
and light response would aid in developing management
strategies.
A more complete knowledge of the sources and causes of
the various light attenuation components would help in
developing management strategies for reducing light at-
tenuation in Chesapeake Bay. The epiphyte component of
light attenuation needs further research attention, particu-
larly with regard to nutrient enrichments. The empirical
connection between dissolved water column nutrients (dis-
solved inorganic nitrogen and dissolved inorganic phos-
phorus) and SAV survival needs to be more fully explored.
Epiphytes do not have the constant light absorption charac-
teristics due to differences in species composition and
epiphyte trapping of fine-grained inorganic material. Thus,
the light attenuation characteristics, rather than just epi-
phyte biomass, need to be quantified as a function of
nutrient conditions. The interaction of epiphytes and phy-
toplankton, both of which respond to water column nutrient
availability, also requires research attention. In addition,
the interaction of the organic component of light absorption
(principally epiphytes and phytoplankton) with the inor-
ganic component is important in determining SAV re-
sponses.
For application of SAV habitat requirements in a manage-
ment context, the standing stock measurements of nutrients
(dissolved inorganic nitrogen and dissolved inorganic phos-
phorus), total suspended solids and chlorophyll a need to be
translated into human activities that affect loading rates of
sediments and nutrients. Further development of the habitat
requirements approach could address the issue of loading
rates. This could begin to be addressed by considering the
total nutrient amounts, not just dissolved inorganic nutrient
concentrations.
Chesapeake Bay is unique in the wealth of SAV distribu-
tional data available, and continued bay'wide surveys are
necessary in order to assess SAV responses to improve-
ments in water quality. Both remote sensing techniques and
ground-truthing are required for accurate surveys. Im-
provements in techniques that are forthcoming with the
recent technological advances in geographic information
systems will need to be integrated with current techniques
171
CSC.SAV.12/92
-------
SAV Technical Synthesis
inamannerthatinsures consistency. Baywide water quality
monitoring also needs to be continued to assess SAV
responses to changes in water quality with a particular
emphasis on maintaining appropriate lower detection limits
for the dissolved nutrient parameters. The ongoing Chesa-
peake Bay Monitoring Program, which focuses on the mid-
channel portions of the Bay mainstem and tidal tributaries,
needs to be supplemented with a sampling program in the
shallows where SAV grow to ensure that mid-channel data
continues to adequately characterize shallow habitats.
The use of experimental SAV transplants has been valuable
for distinguishing water quality impacts from availability of
propagules for establishment of SAV. Further use of this
approach could establish the validity of the habitat require-
ments in a variety of locations throughout Chesapeake Bay.
In particular, transplants of various SAV species along
well-defined depth gradients would help to further quantify
any differences in light attenuation characteristics that may
exist between different SAV species with different growth
morphologies (e.g., canopy-forming versus meadow-form-
ing SAV) or different physiological tolerances to low light
conditions.
The empirical approach used to develop SAV habitat re-
quirements allows for predictive capacity without detailed
quantification of the precise nature of SAV/water quality
interactions. Since SAV in Chesapeake Bay is less than
10% of the Tier III SAV distribution restoration target and
less than 53% of the Tier I SAV distribution restoration
target, there is a need to provide water quality guidelines
before a more complete understanding of the complex
ecological interactions is reached. Notwithstanding future
research efforts to better quantify the individual SAV water
quality parameter interactions accounted for by the SAV
habitat requirements, the SAV habitat requirements devel-
oped through this synthesis can, at this time, be directly
integrated into and applied within ongoing Bay restoration
management programs.
Finally, we need to maintain continuous interactions and
feedback between the researchers who continue to investi-
gate SAV/water quality interactions and the managers who
are responsible for ultimate protection, restoration, and
enhancement of living resources. Continued research and
monitoring of water quality and SAV, coupled with man-
agement towards specific restoration targets, is paramount
if these resources are to be part of our future.
172
CSftSAV.tZ.'K
-------
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183
CSC.SAV.12/92
-------
SAV Technical Synthesis
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CSOSAV.1SSW
-------
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' 185
CSC.SAV.12B2
-------
SAV Technical Synthesis
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186
-------
Appendix A - Table A-1
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Appendix B—Table 1
Table B-1. Summary of analytical methods used in the sample analysis of data presented in the upper Potomac River case
study and the nearshore/midchannel chapter.
All samples preserved by chilling; USGS nutrient samples were also preserved with mercuric chloride beginning in
October 1980. MWCOG is the Metropolitan Washington Council of Governments Potomac Database; WATSTORE
is the U.S. Geological Survey National Water Data Storage and Retrieval System; CBP code is the Chesapeake Bay
Program Code; EPA is the U.S. EPA manual of methods, EPA-600/4-79-020; WY is water year (October through
September); USGS is U.S. Geological Survey; USGSL is U.S. Geological Survey Atlanta Laboratory; USGSR is
U.S.G.S. office in Reston, VA; DCRA is District of Columbia Department of Consumer and Regulatory Affairs; CRL
is U.S. EPA Central Regional Laboratory; MDE is Maryland Department of the Environment; MDHMH is Maryland
Department of Health and Mental Hygiene Laboratory; VSWCB is Virginia State Water Control Board; and, DCLS is
Virginia Division of Consolidated Laboratories.
DISSOLVED AMMONIA (mg/1)
MWCOG code = NH3_N, WATSTORE code = 00608, CBP code = NH4
Agency
Method
Comments
USGS/USGSL
(WY 1979-1981, 1983)
DCRA/CRL
(1983-1989)
Skougstad et al, 1979;
1-2523-78 Colorimetric,
Indophenol, Automated
(Detection limit-0.01).
EPA, 1983; #350.1-1-6
Colorimetric, Automated
Phenate, AAII
(Detection limit-0.04).
Filtered in the field.
0.45 micron filter.
Filtered in the lab.
Preserved with sulfuric
acid.
B-1
CSC.SAV.12/92
-------
SAV Technical Synthesis
TOTAL AMMONIA (mg/1)
MWCOG code = NH3_N, WATSTORE code = 00610, CBP code = NH4W
Agency
Method
Comments
USGS/USGSL
(WY 1979-1981)
(not in 1983)
Skougstadetal, 1979; 1-4523-78
(Detection limit-0.01).
Unfiltered.
MDE/MDHMH
(1983-1989)
VSWCB/DCLS
(1983-1989)
Am. Pub. Health Assoc., 1985;
#417G, Automated Phenate, AAII
(Detection limit-0.008 6/1/1986-1988;
detection limit - 0.02 198J
5/31/1986).
EPA, 1979; #350.1-4-4
Colorimetric, Automated Phenate
Technicon Auto Analyzer I
(Detection limit - 0.1).
Unfiltered.
Samples with possible
pH interferences are not
adjusted before analysis.
Unfiltered.
Note: Ammonia nitrogen—USGS method 1-2523, EPA 350.1, and Standard Methods #417G are similar. The 0-5 mg/1
range used by the USGS is wider than the 0-2 mg/1 for EPA and Standard Methods. This will probably result in
more scatter at lower concentrations.
B-2
CSOSAV.12/92
-------
Appendix B - Table B-1
NITRITE PLUS NITRATE (mg/1)
MWCOG stored NO2_N and NO3_N separately in the computer. For this parameter, NO3_N was added to NO2_N.
WATSTORE code = 00631 (filtered) which was used if available. If not available, this parameter was calculated by
adding 00613 (NO2_N) plus 00618 (NO3_N) (both filtered). CBP code = NO23.
Agency
Method
Comments
USGS/USGSL
(WY 1979-1981,
1983)
NO23_N—Skougstad era/., 1979;
1-2545-78, Colorimetric, Cd
Reduction, Automated
(Detection limit-0.01).
Filtered in the field.
USGS/USGSL
(WY 1979-1981,
1983)
NO2_N—Skougstad et al, 1979;
1-2540-78, Colorimetric,
Diazotization,
Automated, 1981 (00613)
(Detection limit - .01).
Filtered in the field.
USGS/USGSL
(WY 1983)
NO3_N—Skougstad etal, 1979;
Ion Chromatography
(Detection limit - 0.01).
Filtered in the field.
DCRA/CRL
(1983-1989)
EPA, 1983; #353.2-1-7
Colorimetric,
Automated AAII
(Detection limit-0.05).
Filtered in the lab.
Preserved in the field
with sulfuric acid.
MDE/MDHMH
(1983-1989)
Am. Pub. Health Assoc., 1985;
#418F, pp.400-402, Colorimetric,
Automated, Technicon
Auto Analyzer
(Detection limit-0.02 for NO_3 and
.002forNO_2).
Unfiltered.
VSWCB/DCLS
(1983-1989)
EPA, 1979; #353.2-1-7
Technicon Auto
Analyzer I
(Detection limit - 0.05).
Unfiltered.
Note: Nitrate is highly soluble, therefore, total and dissolved were considered to be equal; Nitrite nitrogen—USGS
method 1-2540 and EPA method 353.2 are similar in principle. It is not clearly stated in the EPA procedure what
analytical range is recommended although it appears to be 0-10 mg/1. If this range is used, severe deterioration would
occur for most nitrite values since they are typically low. The USGS range is 0-1.0 mg/1. Nitrate nitrogen—USGS
method 1-2545, EPA 353.2, and Standard Methods 418F are similar in principle and analytical ranges.
B-3
CSC.SAV.12/92
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SAV Technical Synthesis
TOTAL KJELDAHL NITROGEN (mg/1)
MWCOG code = TKN, WATSTORE code = 00625, CBP code = TKNW
Agency
Method
Comments
USGS/USGSL
(WY1979-1981,
1983)
DCRA/CRL
(1983-1987)
Skougstad et al, 1979; Unfiltered.
1-4552-78, Block Digestion and
Colorimetric, Automated
(Detection limit-0.01).
EPA, 1983; #351.2 Unfiltered.
Colorimetric, Semi-automated
Block Digestion AAII
(Detection limit-0.1).
MDE/MDHMH
(1983-1989)
VSWCB/DCLS
0983-1989)
EPA, 1979; #351.2
Colorimetric, Semi-automated
Block Digestion, Technicon
Technicon Auto Analyzer
(Detection limit-0.1).
EPA, 1979; #351.2-1-5
Colorimetric, Semi-automated
Block Digestion AAH
(Detection limit - 0.1).
Unfiltered.
Unfiltered.
Note: Kjeldahl nitrogen—USGS method 1-2552 and EPA method 351.2 are similar and should produce equivalent
results; however, the analytical range (0-20 mg/1) is somewhat wider than the USGS (0-10 mg/1). This may cause
more scatter at lower concentrations.
TOTAL NITROGEN (mg/1)
MWCOG code = calculated by adding TKN plus NO2 plus NO3,
WATSTORE code = calculated by adding 00625 to nitrite plus nitrate, CBP code = TN
Agency
Method
Comments
USGS/USGSL
(WY 1979-1981,
1983)
DCRA/CRL
(1983-1987)
MDE/MDHMH
0983-1989)
VSWCB/DCLS
(1983-1989)
See Total Kjeldahl and Total
Nitrite plus Nitrate.
See Total Kjeldahl and Dissolved
Nitrite plus Nitrate.
See Total Kjeldahl and Total
Nitrite plus Nitrate.
See Total Kjeldahl and Total
Nitrite plus Nitrate.
B-4
CSCSAV.12/92
-------
Appendix B-TabteB-1
TOTAL ORGANIC NITROGEN (mg/1)
MWCOG code = calculated by subtracting NH3_N from TKN,
WATSTORE code = calculated by subtracting 00610 from 00625, CBP code = TON
Agency
USGS/USGSL
MDE/MDHMH
VSWCB/DCLS
Method
See Total Ammonia and Total Kjeldahl
See Total Ammonia and Total Kjeldahl
See Total Ammonia and Total Kjeldahl
Comments
TOTAL PHOSPHORUS (mg/1)
MWCOG code = TP, WATSTORE code = 00665, CBP code = TP
Agency
Method
Comments
USGS/USGSL
(WY1979-1981,
1983)
DCRA/CRL
(1983-1987)
MDE/MDHMH
(1983-1989)
VSWCB/DCLS
(1983-1989)
Skougstad etal, 1979;
1-4600-78
Colorimetric, Phosphomolybdate,
Automated
(Detection limit-0.001).
EPA, 1983; #365.1-1-9
Colorimetric, Automated,
Ascorbic Acid, AAII
(Detection limit - 0.01).
EPA, 1979; #365.4-1-3
Semi-automated Block
Digestion, Colorimetric,
Ascorbic Acid Reduction,
Technicon Auto Analyzer
(Detection limit - 0.01).
EPA, 1979; #365.4-1-3
Colorimetric, Automated,
Block Digestion AAII
(Detection limit - 0.1).
Unfiltered.
Unffltered.
Unfiltered.
Unfiltered.
Note: EPA methods 365.1 and 365.4 use different digestion procedures and the analytical range is much greater (0-
20 mg/1 vs 0-2 mg/1) than the USGS. The different digestion technique may or may not result in different values;
however, the wide analytical range will certainly cause a deterioration in analytical results at lower concentrations.
B-5
CSC.SAV.12/92
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SAV Technical Synthesis
DISSOLVED ORTHOPHOSPHATE (mg/1)
MWCOG code = OP, WATSTORE code = 00671, CBP code = P04F
Agency
Method
Comments
USGS/USGSL
0983)
DCRA/CRL
(1983-1988)
MDE/MDHMH
0983-1989)
Skougstad etal, 1979;
1-2601-78
Colorimetric, Phosphomolybdate,
Automated
^election limit -.001).
EPA, 1979; #365.1-1-9
Colorimetric, Ascorbic
Acid, AAH
0>ection limit - 0.007).
EPA, 1979; #365.1
Changed by 1985 to:
Am. Pub. Health Assoc., 1985;
#424G, p. 450-453.
Automated, Colorimetric Ascorbic
Acid Reduction, Technicon Auto
Analyzer
ODetection limit - 0.004 6M986-1988;
detection limit - 0.011983-5/31/1986).
Filtered.
Filtered in the lab.
Preserved with sulfuric
acid.
Unfiltered.
VSWCB/DCLS
0983-1989)
EPA, 1979; #365.1-1-9
Technician Auto Analyzer I
ODetection limit - 0.01).
Unfiltered.
Note: Orthophosphate—USGS method 1-2601 and EPA method 365.1 are similar. The EPA method #365.1 (analytical
range 0.01-1 mg/1) is better at lower concentrations than #424G (analytical range .001-10 mg/1).
TOTAL SOLUBLE PHOSPHORUS (mg/1)
MWCOG code = TSP, WATSTORE code = 00666, CBP code = TOP
Agency
Method
Comments
USGS/USGSL
(WY1979,
1980,1981,
1983)
DCRA/CRL
0983-1987)
Skougstad et al, 1979; 1-2600-78 Filtered.
Detection limit - 0.001).
EPA, 1979; #365.1-1-9 Filtered.
Colorimetric, Automated,
Ascorbic Acid.
B-6
CSftSAV.iaSZ
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Appendix B - Table B-1
TOTAL SUSPENDED SOLIDS (mg/1)
MWCOG code = TSS, WATSTORE code = 80154
Agency
Method
Comments
USGS/USGSL
(WY1979-1981
1983)
DCRA/CRL
(1983-1988)
MDE/MDHMH
(1983-1989)
VSWCB/DCLS
(1983-1990)
Skougstad et al, 1979; 1-3765-78
Residue dried at 105>C.
Dried overnight
(Detection limit - 1.0).
Am. Publ. Health Assoc., 1985;
Residue dried at 103-lOyC
(Detection limit - 4.0).
Am. Publ. Health Assoc., 1985;
#209C
Residue dried at 103-105)C
for 75-90 minutes
(Detection limit -1.0,1983-88;
detection limit - 0.8,1989).
Fishman and Friedman, 1989;
1-3765-85.
Sample is filtered through
a glass fiber filter.
A well-mixed sample is filtered
through Whatman 934-AH glass
micro-fiber filter. Sample
amount is subjective to amount
of solid in sample.
Note: Total suspended solids—The Standard Methods 208D or 209C-D and the USGS procedure (1-3765) are
basically the same except for the drying times. The Standard Methods call for about an hour of drying time while the
USGS procedure recommends drying overnight. Although the differences between results will probably be small, the
USGS method may produce lower and more accurate results.
B-7
CSC.SAV.1S52
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SAV Technical Synthesis
CORRECTED CHLOROPHYLL a (pg/1)
MWCOG code = CHLAM, WATSTORE code = 32211, 32209
Agency
Method
Comments
USGS/USGSR
(WY1979-1981,
1983)
DCRA/CRL
0983-1988)
MDE/MDHMH
(1983-1989)
VSWCB
(1983-1990)
Fluorometric method (Blanchardef
al, 1982)
(Spectrophotometric method until
the first week of the 1980 WY;
detection limit - 0.2).
Am. Pub. Health Assoc., 1985;
D3731-79, pp. 1079-1083
(Detection limit -1.0).
Am. Pub. Health Assoc., 1985;
1002G-1 Spectrophotometric method
pp. 1067-1070 (Beckman DU-6)
(Detection limit - unavailable).
EPA, 1973; (Monochromatic)
pp. 14-16;
Jeffrey and Humphrey, 1975;
(Trichromatic)
(Detection limit - unavailable).
30-40 mis filtered through
glass fibre filter.
Filter preserved in 90%
acetone, chilled, and kept dark.
In the absence of pheophytin,
the trichromatic practice is
used.
Millipore vacuum
filtration system.
Measured in mg/1, pheophytin
measured at 665 nm after
acidification.
Trichromatic equation: Chla -
11.85 (OD664) -1.54 (OD647) •
0.08 (OD630).
Note: Chlorophyll a—the trichromatic method (D 3731-79), the Spectrophotometric methods (1002G-1), and the
fluorometric method (USGS B6630) use different analytical approaches. There may not be good agreement between
laboratories since this determination is quite technique dependent.
B-8
CSOSAV.12S2
-------
Appendix B - Table B-1
DISSOLVED INORGANIC PHOSPHORUS (mg/1)
MWCOG code = OP, WATSTORE code = 00666, CBP code = TOP, P04F
Agency
Method
Comments
USGS/USGSL
(WY1980-1981)
DCECD/CRL
(1983 -1988)
See Total Soluble Phosphorus
See Dissolved Orthophosphate
MDE/MDHMH
(1983-1989)
See Dissolved Orthophosphate
DISSOLVED INORGANIC NITROGEN (mg/1)
MWCOG code = NH3_N plus NO2_N plus NO3_N, WATSTORE code = 00608 plus 00631
or 00608 plus 00618, CBP code = NH4 plus NO23 or NH4W plus NO23
Agency
Method
Comments
USGS/USGSL
(WY 1980,1981)
DCECD/CRL
(1983-1988)
MDE/MDHMH
(1983-1989)
See Dissolved Ammonia and Nitrite
plus Nitrate
See Dissolved Ammonia and Nitrite
plus Nitrate
See Total Ammonia and Nitrite plus
Nitrate
B-9
CSC.SAV.12/92
-------
-------
Appendix C — Table 1
Table C-1. References documenting historical and present Chesapeake Bay SAV species distribution by Chesapeake Bay
Program Segment.
Segment CB1 — Northern Chesapeake Bay
Species
Ceratophyllum demersum
Cham sp.
Elodea canadensis
Heteranthera dubia
Hydrilla verticillata
Myriophyllum spicatum
Najas sp.
Najas flexilis
Najas gracillima
Najas guadalupensis
Najas minor
Potamogeton amplifolius
Potamogeton gramineus
Reference
Kerwin et al, 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Bayley et al., in press; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Bayley et al., in press; Kerwin et al., 1975a;
Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b; Stevenson and
Confer, 1978; Davis, 1985.
Orth et al., 1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Orth et al, 1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Bayley et al., in press; Kerwin et al., 1975a;
Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b; Stevenson and
Confer, 1978; Davis, 1985; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Bayley et al., in press; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey
Database 1987.
Brush and Davis, 1984; Brush and Hilgartner, 1989; Davis, 1985.
Davis, 1985.
Brush and Hilgartner, 1989; Davis, 1985; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Davis, 1985.
Springer et al., 1958; Stevenson and Confer, 1978.
Springer et al., 1958; Stevenson and Confer, 1978.
C-1
CSOSAV.12/92
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SAV Technical Synthesis
Segment CB1 — Northern Chesapeake Bay (Continued)
Species
Potamogeton nodosus
Potamogeton diversifolius
Potamogeton epihydrus
Potamogeton pectinatus
Potamogeton perfoliatus
Vallisneria americana
Zannichellia palustris
Reference
Springer et al., 1958; Stevenson and Confer, 1978.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Bayley et al., in press; Stevenson and Confer, 1978; Orth et al., 1986;
Aerial Survey Database 1987; Orth and Nowak, 1990.
Bayley et al., in press; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Bayley et al., in press; Kerwin et al., 1975a;
Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b; Stevenson and
Confer, 1978; Davis, 1985; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Brush and Hilgartner, 1989.
Segment CB2 — Upper Chesapeake Bay
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Heteranthera dubia
Hydrilla vericillata
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Reference
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Stotts, 1970; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Aerial Survey Database 1987.
Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro 1976a; Munro 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Stotts 1960; Stotts, 1970; Stevenson and Confer, 1978.
Aerial Survey Database 1987.
Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
C-2
CS&&W.12B2
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Appendix C - Table G-1
Segment CB2 — Upper Chesapeake Bay (Continued)
Species
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Stotts, 1970; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Segment CBS — Upper Central Chesapeake Bay
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Hydrilla verticillata
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Reference
Stotts, 1960; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, I960; Stotts, 1970; Stevenson and Confer, 1978.
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987.
Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
C-3
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SAV Technical Synthesis
Segment CBS — Upper Central Chesapeake Bay (Continued)
Species
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Kerwin et al, 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Segment CB4 — Middle Central Chesapeake Bay
Species
Ceratopyllum demersum
Elodea canadensis
Myriophyllmn spicatum
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Orth and Nowak, 1990.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
C-4
CSC.SAV.12.-72
-------
Appendix C - Table C-1
Segment CB4 — Middle Central Chesapeake Bay (Continued)
Species
Zostera marina
Reference
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978.
Segment CBS — Lower Chesapeake Bay
Species
Potamogeton pectinatus
Ruppia maritima
Zannichellia palustris
Zostera marina
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth et al., 1979; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a,
Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth et al., 1979; Orth and Nowak, 1990.
Segment CB6 — Western Lower Chesapeake Bay
Species
Ruppia maritima
Zostera marina
Reference
Aerial Survey Database 1987; Orth and Nowak, 1990.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Segment CB7 — Eastern Lower Chesapeake Bay
Species
Potamogeton pectinatus
Ruppia maritima
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth et al.,
1979; Orth and Nowak, 1990.
C-5
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SAV Technical Synthesis
Segment CB7 — Eastern Lower Chesapeake Bay (Continued)
Species
Zostera marina
Zannichellia palustris
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth et al.,
1979; Orth and Nowak, 1990.
Aerial Survey Database 1987; Orth et al., 1979.
Segment CBS — Mouth of Chesapeake Bay
Species
Ruppia maritima
Zostera marina
Segment WT1 — Bush River
Reference
Aerial Survey Database 1987; Orth and Nowak, 1990.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Species
Ceratophyttum demersum
Chara sp.
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Elser, 1969; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro 1976a;
Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey Database
1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Elser, 1969; Stevenson and Confer, 1978; Aerial Survey Database 1987.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
C-6
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Appendix C - Table C-1
Segment WT2 — Gunpowder River
Species
Ceratophyllum demersum
Cham sp.
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Najas gracillima
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a,
Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978; Southwick,
1967-1969; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Stotts, 1960; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Elser, 1969; Kerwin et al., 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Stotts, 1960; Stevenson and
Confer, 1978; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Orth and
Nowak, 1990.
Segment WT3 — Middle River
Species
Ceratophyllum demersum
Chora sp.
Reference
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
C-7
CSC.SAV.12/92
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SAV Technical Synthesis
Segment WT3 — Middle River (Continued)
Species
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Najas gracillimas
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Brush and Hilgartner, 1989; Kerwin et al, 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth and Nowak, 1990.
Stotts, 1960; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Brush and Hilgartner, 1989.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Stotts, 1960; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Orth and
Nowak, 1990.
Segment WT4 — Back River
Species
Ceratophyllum demersum
Chara sp.
Reference
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Stevenson and Confer, 1978.
C-8
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Appendix C - Table C-1
Segment WT4 — Back River (Continued)
Species
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Najas gracillima
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Brush and Hilgartner, 1989; Kerwin et al, 1975a; Kerwin et al., 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stevenson and Confer, 1978; Southwick, 1967-1969; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Stotts, 1960; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989.
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Kerwin et al, 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Stotts, 1960; Stevenson and Confer, 1978;
Aerial Survey Database 1987.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Orth and
Nowak, 1990.
Segment WT5 — Patapsco River
Species
Ceratophyllum demersum
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton pectinatus
Reference
Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Brush and Hilgartner, 1989.
Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Orth and Nowak, 1990.
C-9
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SAV Technical Synthesis
Segment WT5 — Patapsco River (Continued)
Species
Potamogeton peifoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al., 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Segment WT6 — Magothy River
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton pectinatus
Potamogeton perfoliatus
Reference
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Elser, 1969; Stevenson and Confer, 1978; Personal communication from
Younger, Consulting Biologists, Inc. to Roach, 1963; Orth and Nowak,
1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Personal communication from Younger, Consulting Biologists, Inc.
to Roach, 1963; Orth and Nowak, 1990.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Personal communication from Younger,
Consulting Biologists, Inc. to Roach, 1963.
C-10
CSOSAV.12%
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Appendix C - Table C-1
Segment WT6 — Magothy River (Continued)
Species
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Kerwin et al, 1975a; Kerwin etal, 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Segment WT7 — Severn River
Species
Ceratophyllum demersum
Chora sp.
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton pectinatus
Potamogeton perfoliatus
Reference
Kerwin et al., 1975a; Kerwin etal., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Elser, 1969; Kerwin et al., 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Phillip and Brown, 1965;
Southwick and Pine, 1975; Stevenson and Confer, 1978; Aerial Survey
Database 1987.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Phillip and Brown, 1965; Southwick and Pine, 1975;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Phillip and Brown, 1965; Southwick and Pine, 1975; Stevenson and
Confer, 1978; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Elser, 1969; Kerwin et al, 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986.
C-11
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SAV Technical Synthesis
Segment WT7 — Severn River (Continued)
Species
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Brush and Hilgartner, 1989; Kerwin et at., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Orth and
Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Southwick and Pine, 1975; Stevenson and
Confer, 1978; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Segment WT8 — South, Rhode, and West Rivers
Species
Elodea canadensis
Myriophyllum spicatum
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Phillip and Brown, 1965; Southwick and Pine, 1975; Stevenson and
Confer, 1978.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stevenson and Confer, 1978; Phillip and Brown, 1965;
Southwick and Pine, 1975.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stevenson and Confer, 1978; Phillip and Brown, 1965;
Southwick and Pine, 1975; Orth and Nowak, 1990.
Elser, 1969; Stevenson and Confer, 1978; Phillip and Brown, 1965;
Southwick and Pine, 1975.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stevenson and Confer, 1978; Phillip and Brown, 1965;
Southwick and Pine, 1975; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Stevenson and Confer, 1978.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Phillip and Brown, 1965; Southwick and
Pine, 1975; Aerial Survey Database 1987; Orth and Nowak, 1990.
C-12
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Appendix C - Table C-1
Segment TF1 — Upper Patuxent River
Species
Ceratopyllum demersum
Elodea canadensis
Najas sp.
Najas flexilis
Najas guadalupensis
Potamogeton crispus
Potamogeton diversifolius
Potamogeton epihydrus
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989; Orth and Nowak, 1990.
Orth and Nowak, 1990.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Anderson et al., 1967; Stevenson and Confer, 1978.
Orth and Nowak, 1990.
Anderson et al., 1967; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978.
Segment RET1 — Middle Patuxent River
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Myriophyllum spicatum
Reference
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Orth and Nowak, 1990.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Orth and Nowak, 1990.
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987.
C-13
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SAV Technical Synthesis
Segment RET1 — Middle Patuxent River (Continued)
Species
Najas sp.
Najas flexilis
Najas guadalupensis
Potamogeton crispus
Potamogeton diversifolius
Potamogeton epihydrus
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Orth and Nowak, 1990.
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Orth and Nowak, 1990.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Brush and Davis, 1984; Davis, 1985; Brush and Hilgartner, 1989.
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Anderson et al, 1969; Stevenson and Confer, 1978.
Orth and Nowak, 1990.
Anderson et al., 1969; Kerwin et al, 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey
Database 1987.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987.
Elser, 1969; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978.
Segment LEI —Lower Patuxent River
Species
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Reference
Stevenson and Confer, 1978.
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Orth and Nowak, 1990.
Stevenson and Confer, 1978.
C-14
CSOSW.12S2
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Appendix C - Table C-1
Segment LEI —Lower Patuxent River (Continued)
Species
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Stevenson and Confer, 1978; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Anderson et al., 1969; Stevenson and Confer, 1978.
Anderson et al, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978; Maryland Department
of Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Segment TF2 — Upper Potomac River
Species
Ceratophyllum demersum
Chara sp.
Egeria densa
Elodea canadensis
Heteranthera dubia
Hydrllla verticillata
Myriophyllum spicatum
Najas sp.
Najas minor
Reference
Carter et al., 1985a; Carter et al., 1985b; Paschal et al., 1982; Rybicki et
al., 1986; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Rybicki et al., 1987.
Paschal et al, 1982.
Stevenson and Confer, 1978.
Carter et al, 1985a; Carter et al, 1985b; Rybicki et al, 1987; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Rybicki et al, 1986; Rybicki et
al, 1987; Aerial Survey Database 1987; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Rybicki et al, 1986; Rybicki et
al, 1987; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Stewart, 1962; Stevenson and Confer, 1978; Aerial Survey Database 1987.
Rybicki et al, 1987; Orth and Nowak, 1990.
C-15
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SAV Technical Synthesis
Segment TF2 — Upper Potomac River (Continued)
Species
Najas guadalupensis
Najas gracillima
Nitellaflexilis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Carter et al, 1985a; Carter et al., 1985b; Rybicki et al., 1986; Rybicki et
al., 1987; Orth and Nowak, 1990.
Aerial Survey Database 1987.
Carter et al., 1985a; Carter et al, 1985b; Rybicki et al., 1986; Rybicki et
al., 1987.
Carter et al., 1985a; Carter et al, 1985b.
Carter et al, 1985a; Carter et al, 1985b; Rybicki et al, 1986. Rybicki et
al, 1987; Stewart, 1962; Stevenson and Confer, 1978; Orth and Nowak,
1990.
Stevenson and Confer, 1978.
Paschal et al, 1982; Rybicki et al, 1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Carter et al, 1985a; Carter et al, 1985b; Paschal et al, 1982; Rybicki et
al, 1987; Stewart, 1962; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Rybicki et al, 1986; Rybicki et
al, 1987; Aerial Survey Database 1987.
Segment RET2 — Middle Potomac River
Species
Ceratophyllum demersum
Chora sp.
Elodea canadensis
Heteranthera dubia
Hydrilla verticillata
Reference
Carter et al, 1985a; Carter et al, 1985b; Kerwin et al, 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978;
Paschal et al, 1982; Rybicki et al, 1988; Orth and Nowak, 1990.
Paschal et al, 1982.
Paschal et al, 1982; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro,
1976a; Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey
Database 1987.
Rybicki et al, 1988.
Rybicki et al, 1988.
C-16
CSOSAV.12S2
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Appendix C - Table C-1
Segment RET2 — Middle Potomac River (Continued)
Species
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Najas minor
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Carter et al., 1985a; Carter et al, 1985b; Kerwin et al., 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Paschal et al., 1982; Stevenson
and Confer, 1978; Rybicki et al., 1988; Orth and Nowak, 1990.
Paschal et al., 1982; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Carter et al., 1985a; Carter et al., 1985b; Aerial Survey Database 1987.
Rybicki et al., 1988.
Paschal et al., 1982; Rybicki et al., 1987; Aerial Survey Database 1987;
Orth et al, 1979; Orth and Nowak, 1990.
Carter et al., 1985a; Carter et al., 1985b; Paschal et al., 1982; Stevenson
and Confer, 1978; Rybicki et al, 1988; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Kerwin et al, 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Paschal et al, 1982; Stevenson
and Confer, 1978; Orth et al, 1979; Rybicki et al, 1988; Orth and
Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Paschal et al, 1982; Stevenson and Confer, 1978; Aerial Survey Database
1987; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Paschal et al, 1982; Rybicki et
al, 1986; Rybicki et al, 1988; Kerwin et al, 1975a; Kerwin et al,
1975b; Munro 1976a; Munro, 1976b; Stevenson and Confer, 1978; Orth et
al, 1979; Orth and Nowak, 1990.
Carter et al, 1985a; Carter et al, 1985b; Paschal et al, 1982; Rybicki et
al, 1987; Aerial Survey Database 1987; Orth et al, 1979.
Segment LE2 — Lower Potomac River
Species
Chara sp.
Elodea panadensis
Myriophyllum spicatum
Reference
Paschal et al, 1982.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Paschal et al, 1982; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Paschal et al, 1982; Rybicki et al, 1987; Stevenson and Confer, 1978.
C-17
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SAV Technical Synthesis
Segment LE2 — Lower Potomac River (Continued)
Species
Najas sp.
Najas guadalupensis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zastera marina
Reference
Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Paschal et al., 1982; Stevenson and Confer, 1978.
Carter et al, 1985a; Carter et al., 1985b.
Paschal et al., 1982.
Paschal et al., 1982; Stevenson and Confer, 1978.
Carter et al., 1985a; Carter et al., 1985b; Rybicki et al., 1987; Kerwin et
al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b; Paschal et
al., 1982; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Paschal et al, 1982.
Carter et al, 1985a; Carter et al, 1985b; Paschal et al, 1982; Rybicki et
al, 1987; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Paschal et al, 1982; Rybicki et al, 1987; Stevenson and Confer, 1978;
Aerial Survey Database 1987.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Paschal et al, 1982; Stevenson and Confer, 1978.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Aerial Survey Database 1978; Orth and
Nowak, 1990.
Segment TF3 — Upper Rappahannock River
Species
Ceratophyllum demersum
Ruppia maritima
Zannichellia palustris
Zostera marina
Reference
Orth et al, 1979.
Orth, 1971; Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978.
C-18
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Appendix C - Table C-1
Segment RET3 — Middle Rappahannock River
Species
Callitriche verna
Ceratophyllum demersum
Nqjas sp.
Potamogeton epihydrus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Orth et al, 1979.
Orth et al, 1979.
Orth et al., 1979.
Stevenson and Confer, 1978.
Orth, 1971; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Orth et al, 1979.
Stevenson and Confer, 1978; Orth et al, 1979.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Orth and Nowak,
1990.
Segment LE3 — Lower Rappahannock River
Species
Ceratophyllum demersum
Callitriche vema
Elodea canadensis
Najas sp.
Nitellaflexilis
Myriophyllum spicatum
Potamogeton epihydrus
Ruppia maritima
Zannichellia palustris
Zostera marina
Reference
Orth et al, 1979.
Orth etal, 1979.
Orth et al, 1979.
Orth et al, 1979.
Orth et al, 1979.
Orth et al, 1979.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth et al, 1979; Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth et al, 1979.
Orth, 1973; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth et al, 1979; Orth and Nowak, 1990. , ,
C-19
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SAV Technical Synthesis
Segment TF4 — Upper York River
Species
Ceratophyllum demersum
Elodea canadensis
Nitellaflexilis
Potamogeton pectinatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Segment RET4 — Middle York River
Reference
Orth et al, 1979.
Stevenson and Confer, 1978.
Orth et al., 1979.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Orth et al, 1979.
Orth et al, 1979.
Stevenson and Confer, 1978.
Species
Elodea canadensis
Potamogeton pectinatus
Ruppia maritima
Vallisneria americana
Zostera marina
Segment LE4 — Lower York River
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Orth and Nowak,
1990.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Species
Elodea canadensis
Potamogeton pectinatus
Ruppia maritima
Vallisneria americana
Zostera marina
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
C-20
CSCSAV.1292
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Appendix C - Table C-1
Segment WE4 — Mobjack Bay
Species
Elodea canadensis
Potamogeton pectinatus
Ruppia maritima
Vallisneria americana
Zostera marina
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Orth, 1971; Orth, 1973; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth et al., 1979; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Orth, 1971; Orth, 1973; Kerwin et al, 1975a; Kerwin et al., 1975b;
Munro, 1976a; Munro, 1976b; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth et al., 1979; Orth and Nowak, 1990.
Segment TF5 — Upper James River
Species
Ceratophyllum demersum
Chara sp.
Najas guadalupensis
Segment RETS —Middle James River
Reference
Orth and Nowak, 1990.
Orth and Nowak, 1990.
Orth and Nowak, 1990.
Species
Ceratophyllum demersum
Chara sp.
Najas sp.
Najas guadalupensis
Ruppia maritima
Zostera marina
Segment LE5 — Lower James River
Reference
Orth et al., 1979.
Orth and Nowak, 1990.
Orth et al., 1979.
Orth and Nowak, 1990.
Aerial Survey Database 1987.
Aerial Survey Database 1987.
Species
Ceratophyllum demersum
Reference
Orth et al., 1979.
C-21
CSC.SAV.12S2
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SAV Technical Synthesis
Segment LE5 — Lower James River (Continued)
Species
Najas sp.
Ruppia maritima
Zostera marina
Segment ET1 — Northeast River
Reference
Orth et al., 1979.
Aerial Survey Database 1987.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Hydrilla verticillata
Myriophyllum spicatum
Najas sp.
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Vallisneria americana
Zannichellia palustris
Reference
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Orth and Nowak, 1990,
Orth and Nowak, 1990.
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Segment ET2 — Elk and Bohemia Rivers
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Reference
Stevenson and Confer, 1978; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Orth and
Nowak, 1990.
C-22
CSC.SAV.tt-K
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Appendix C - Table C-1
Segment ET2 — Elk and Bohemia Rivers (Continued)
Species
Heteranthera dubia
Hydrilla verticillata
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Najas gracillima
Potamogeton crispus
Potamogeton diversifolius
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Aerial Survey Database 1987.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Stevenson and Confer, 1978; Aerial Survey Database 1987.
Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989.
Orth and Nowak, 1990.
Brush and Hilgartner, 1989.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978.
Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Orth and
Nowak, 1990.
Segment ET3 — Sassafras River
Species
Chora sp.
Ceratophyllum demersum
Elodea canadensis
Heteranthera dubia
Hydrilla verticillata
Reference
Stevenson and Confer, 1978.
Elser, 1969; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Aerial Survey Database 1987.
Aerial Survey Database 1987; Orth and Nowak, 1990.
C-23
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SAV Technical Synthesis
Segment ET3 — Sassafras River (Continued)
Species
Myriophyllum spicatum
Najas sp.
Najas gracillima/muenscheri
Najas guadalupensis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton petfoliatus
Ruppia maritima
Trapa natans
Vallisneria americana
Zannichellia palustris
Reference
Elser, 1969; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987.
Brush and Hilgartner, 1989.
Brush and Hilgartner, 1989.
Orth et al., 1987; Orth and Nowak, 1990.
Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Stevenson and Confer, 1978.
Orth and Nowak, 1990.
Aerial Survey Database 1987.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Orth and Nowak, 1990.
Segment ET4 —Chester River
Species
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Reference
Stotts, 1960; Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Orth and
Nowak, 1990.
C-24
CSaSAV.12.-K
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Appendix G-Table G-1
Segment ET4 —Chester River (Continued)
Species
Myrlophyllum spicatum
Najas sp.
Najas guadalupensis
Najas gracillima
Potamogeton pectinatus
Potamogeton perfoliatus
Potamogeton pusillus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Zostera marina
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Muriro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Orth and
Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Brush and Hilgartner, 1989.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al., 1975b;
Munro, 1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and
Confer, 1978; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and
Confer, 1978; Maryland Department of Natural Resources Ground Survey,
1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
Brush and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stotts, 1970; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Kerwin et al, 1975a; Kerwin et al, 1975b;
Munro, 1976a; Munro, 1976b; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Segment ET5 — Choptank River
Species
Elodea canadensis
Reference
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986.
C-25
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SAV Technical Synthesis
Segment ET5 — Choptank River (Continued)
Species
Myriophyllum spicatum
Najas guadalupensis
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Tastera marina
Reference
Stotts, 1970; Stevenson and Confer, 1978.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey
Database 1987; Orth and Nowak, 1990.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
Kerwin et al, 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978.
Segment ET6 — Nanticoke River
Species
Myriophyllum spicatum
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Stotts, 1970; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Segment ET7 — Wicomico River
Species
Myriophyllum spicatum
Potamogeton pectinatus
C-26
CSOSAV.12/S2
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
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Appendix C - Table C-t
Segment ET7 — Wicomico River (Continued)
Species
Potamogeton perfoliatus
Ruppia maritima
Reference
Stevenson and Confer, 1978.
Stotts, 1970; Stevenson and Confer, 1978; Aerial Survey Database 1987;
Orth and Nowak, 1990.
Segment ET8 — Manokin River
Species
Elodea canadensis
Potamogeton pectinatus
Ruppia maritima
Zannichellia palustris
Zostera marina
Reference
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987.
Segment ET9 — Big Annemessex River
Species
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Zostera marina
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987.
C-27
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SAV Technical Synthesis
Segment ET10 — Pocomoke River
Species
Ruppia maritima
Zostera marina
Reference
Kerwin et al., 1975a; Kerwin et at., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978.
Segment EE1 — Eastern Bay
Species
Chara sp.
Ceratophyllum demersum
Elodea canadensis
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Reference
Stotts, 1970; Stevenson and Confer 1978.
Fenwick, unpublished; Stevenson and Confer, 1978.
Fenwick, unpublished; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986.
Elser, 1969; Fenwick, unpublished; Kerwin et al., 1975a; Kerwin et al.,
1975b; Munro, 1976a; Munro, 1976b; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986.
Fenwick, unpublished; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989.
Fenwick, unpublished; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986; Orth and Nowak, 1990.
Fenwick, unpublished; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986; Aerial Survey Database 1987.
Fenwick, unpublished; Kerwin et al, 1975a; Kerwin et al, 1975b; Munro,
1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
C-28
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Appendix C - Table C-1
Segment EE1 — Eastern Bay (Continued)
Species
Zannichellia palustris
Zostera marina
Reference
Brash and Hilgartner, 1989; Fenwick, unpublished; Kerwin et al., 1975a;
Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b; Stotts, 1970;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Fenwick, unpublished; Kerwin et al., 1975a; Kerwin et al., 1975b; Munro,
1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970; Stevenson and Confer,
1978; Maryland Department of Natural Resources Ground Survey, 1971-
1986.
Segment EE2 — Lower Choptank River
Species
Elodea canadensis
Myriophyllum spicatum
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
Reference
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986.
Stotts, 1970; Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986; Aerial
Survey Database 1987; Orth and Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978; Brash and
Hilgartner, 1989; Maryland Department of Natural Resources Ground
Survey, 1971-1986.
Brush, 1987; Brash and Hilgartner, 1989; Kerwin et al., 1975a; Kerwin et
al., 1975b; Munro, 1976a; Munro, 1976b; Stewart, 1962; Stotts, 1960;
Stotts, 1970; Stevenson and Confer, 1978; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
Stotts, 1970; Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978; Brash, 1987; Brash and
Hilgartner, 1989; Maryland Department of Natural Resources Ground
Survey, 1971-1986; Aerial Survey Database 1987; Orth and Nowak, 1990.
C-29
CSC.SAV.12S2
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SAV Technical Synthesis
Segment EE2 — Lower Choptank River
Species
Zostera marina
Reference
Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1960; Stotts, 1970; Stevenson and Confer, 1978;
Maryland Department of Natural Resources Ground Survey, 1971-1986;
Aerial Survey Database 1987.
Segment EE3 — Tangier Sound
Species
Chara sp.
Myriophyllum spicatum
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Zannichellia palustris
Zostera marina
Reference
Stevenson and Confer, 1978.
Stevenson and Confer, 1978.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stewart, 1962; Stotts, 1970; Stevenson and Confer, 1978; Maryland
Department of Natural Resources Ground Survey, 1971-1986.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stotts, 1970; Stevenson and Confer, 1978.
Brush and Hilgartner, 1989; Elser, 1969; Kerwin et al., 1975a; Kerwin et
al, 1975b; Munro, 1976a; Munro, 1976b; Stotts, 1960; Stotts, 1970;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986; Aerial Survey Database 1987; Orth and
Nowak, 1990.
Kerwin et al., 1975a; Kerwin et al., 1975b; Munro, 1976a; Munro, 1976b;
Stevenson and Confer, 1978; Maryland Department of Natural Resources
Ground Survey, 1971-1986.
Elser, 1969; Kerwin et al., 1975a; Kerwin et al, 1975b; Munro, 1976a;
Munro, 1976b; Stotts, 1960; Stotts, 1970; Maryland Department of
Natural Resources Ground Survey, 1971-1986; Aerial Survey Database
1987; Orth and Nowak, 1990.
C-30
CSOSAV.1JW2
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Appendix C — Table 2
Table C-2. Chesapeake Bay SAV species distribution/diversity restoration targets by CBP segment.
SEGMENT CB1
NORTHERN CHESAPEAKE BAY
Ceratophyllum demersum
Cham sp.
Elodea canadensis
Heteranthera dubia
Myriophyllum spicatum
Najas sp.
Najas flexilis
Najas gracillima
Najas guadalupensis
Najas minor
Potamogeton amplifolius
Potamogeton gramineus
Potamogeton nodosus
Potamogeton diversifolius
Potamogeton epihydrus
Potamogeton pectinatus
Potamogeton perfoliatus
Vallisneria americana
Zannichellia palustris
SEGMENT CB2
UPPER CHESAPEAKE BAY
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Heteranthera dubia
Hydrilla vericillata
Myriophyllum spicatum
Najas sp.
Najas guadalupensis
Potamogeton crispus
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Vallisneria americana
Zannichellia palustris
SEGMENT CBS
UPPER CENTRAL CHESAPEAKE BAY
Ceratophyllum demersum
Chara sp.
Elodea canadensis
Myriophyllum spicatum
Najas sp.
C-31
CSC.SAV.12fl2
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