U.S. ENVIRONMENTAL PROTECTION AGENCY
EPA
SUMMARY AND CONCLUSIONS
from the
forthcoming
Technical Report 56
"Nutrient Enrichment
and
Control Requirements
in the
Upper Chesapeake Bay"
MIDDLE ATLANTIC REGION-III 6th and Walnut Streets, Philadelphia, Pennsylvania 19106
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EPA-903/9-73-002-a
SUMMARY AND CONCLUSIONS
from the
forthcoming
Technical Report 56
"Nutrient Enrichment
and
Control Requirements
in the
Upper Chesapeake Bay"
Annapolis Field Office
Region III
Environmental Protection Agency
-------
EPA-903/9-73-002-a
Annapolis Field Office
Region III
Environmental Protection Agency
SUMMARY AND CONCLUSIONS
from the
forthcoming
Technical Report 56
'Nutrient Enrichment and Control Requirements
in the
Upper Chesapeake Bay"
Leo J. Clark
Daniel K. Donnelly
Orterio Villa, Jr.
August 1973
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ABSTRACT
The upper portions of the Chesapeake Bay and its tidal tributaries
are currently suffering from an insidious eutrophication problem as
evidenced by the increased frequency and persistence of undesirable
algal blooms and the dramatic changes in the Bay's natural flora which
have recently been experienced. Water quality monitoring data collected
between 1968 and 1971 have shown an upward trend in phosphorus levels
and indicated that inorganic nitrogen may presently be the growth rate-
limiting nutrient since it is almost nonexistent during peak bloom
conditions. Moreover, utilizing a combination of historical field data
and laboratory data to estimate biological uptake requirements led to
the conclusion that phosphorus was being recycled at least twice during
the algal growing season in the upper Chesapeake Bay.
In order to limit the maximum algal standing crop to 40 yg/1
chlorophyll a_, it was determined that total phosphorus and inorganic
nitrogen concentrations should not exceed 0.12 mg/1 (P04) and 0.8 mg/1,
respectively. The achievement of these concentrations necessitates
the institution of a considerable abatement program in the two areas
responsible for most of the nutrient contributions to the upper Chesa-
peake Bay, namely the Susquehanna River Basin and the Baltimore metro
area. A quasi-verified dynamic estuary water quality model was used
to ascertain the maximum allowable phosphorus and nitrogen loadings
from both areas to maintain the aforementioned criteria for three
different Susquehanna flow conditions (10,000, 30,000 and 50,000 cfs).
For the two lower flow conditions a 70 percent reduction in the
existing phosphorus load would be required from both the Susquehanna
Basin and the Baltimore area. During the high flow condition a
reduction of over 90 percent of the point source discharges in the
Susquehanna must be realized to achieve the phosphorus criterion.
Nitrogen is considerably less manageable in the Susquehanna Basin
than phosphorus, especially during higher flow periods. Nitrogen
control may be a feasible alternative under extremely dry weather
conditions, but concentrated slugs of nitrogen associated with storm
water runoff would undoubtedly contravene the criterion because of
the Bay's exceptionally long flushing time.
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PREFACE
This report is intended to serve as an interim document
for disseminating the Annapolis Field Office's technical information
on the upper Chesapeake Bay. The report presents a series of
conclusions and graphically displayed supportive data relevant
to the current eutrophication problem in the upper Bay. The authors
hope to have a full report elaborating on these findings
completed in the near future.
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1
The Annapolis Field Office of the U. S. Environmental Protection
Agency initiated a routine water quality monitoring program in the
upper Chesapeake Bay during 1968 in order to evaluate the effects
of a wastewater discharge from the proposed Anne Arundel County
Sandy Point Sewage Treatment Plant (STP) near Annapolis, Maryland.
This monitoring effort has continued to the present time and has
expanded in scope to include the following objectives: investigation
of recent trends resulting in the present eutrophic state of the
upper Bay; delineation of major nutrient inputs to the upper Bay;
mathematical model development to establish allowable loadings for
these inputs under varying flow conditions so as not to exceed a given
algal bloom condition; compilation of sufficient statistically
valid data which would allow management decisions to be made in
accordance with desired objectives. Results of AFO studies and related
data collected by other interested agencies are summarized as follows:
1) The Susquehanna River is the major contributor of
freshwater to the upper Chesapeake Bay and is the
primary factor influencing the Bay's salinity regime
and inorganic silt load. The Susquehanna exhibits a
classical hydrograph of high spring flows, often
exceeding 100,000 cfs, and flows of 10,000 cfs or
less during the summer and fall months.
2) The net advective velocities and travel times throughout
the upper Chesapeake Bay system vary directly with
Susquehanna River flows. The theoretical times required
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for a particle of water leaving the Susquehanna
River to reach the vicinity of Annapolis, Md., a
distance of approximately 32 miles, based upon a "plug
flow" analysis are given below for several sustained
flow conditions:
Susquehanna Flow Travel Times
(cfs) (days)
10,000 125
30,000 40
50,000 25
100,000 12
3) Sampling data collected from six transects (A through F)
along the Chesapeake Bay between the entrance to Baltimore
Harbor and the Severn River (see Basin Map in Appendix)
indicated that nitrogen and phosphorus concentrations
within each transect were relatively uniform, both
laterally and vertically, and spatial differences from
one transect to the next were generally small. Spatial
concentration gradients between these transects were
more pronounced for chlorophyll due to the effects of
wind and tide action causing blooms to occur as discrete
patches rather than as a uniform mixture.
4) Compositing all of the transect data collected since
1968 revealed the following:
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a) Maximum concentrations of total phosphorus
(as POJ exceeded 0.2 mg/1 during the late
summer and fall periods of 1969, 1970 and
1971. Minimum concentrations (0.08 - 0.12 mg/1)
were consistently found during the spring.
Total phosphorus concentrations in the upper
Chesapeake Bay have generally shown an
upward trend from 1968 to 1971.
b) Inorganic phosphorus concentrations during the
period 1969 to 1971 varied from about 0.04 mg/1
to 0.18 mg/1. Temporal variations in concentration
paralleled those observed for total phosphorus
with only slight differences in phasing noted.
c) Spatial differences in total phosphorus
concentrations were not extreme in the upper
Chesapeake Bay. Summer data collected from
1969, 1970 and 1971 generally showed concentrations
increasing between the Sassafras River and
Baltimore Harbor and remaining relatively high
downstream of Baltimore Harbor.
d) Total nitrogen (TKN + NOg) and inorganic nitrogen
(NH-, + NOJ concentrations varied from 0.5 mg/1
to 1.2 mg/1 and from 0.05 mg/1 to 1.0 mg/1,
respectively, during the study period. Both
parameters exhibited similar seasonal variations
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with maximum concentrations observed in the
winter and spring and minimum values in the
summer.
e) Of the two components comprising inorganic
nitrogen, the nitrate form was predominant
(0.6 mg/1 vs. 0.3 mg/1 ammonia nitrogen)
during algal non-bloom periods while both
were minimal during peak bloom periods. This,
coupled with the fact that the Susquehanna
River water entering the Bay is highly nitrified
(refer to table on page 10), would appear to
indicate that (1) the nitrification reaction
(NHv+NOg) is comparatively insignificant in the
Bay and (2) inorganic nitrogen may be the algal
growth rate-limiting nutrient at the present
time.
f) Organic nitrogen levels were greatest (0.4 -
0.5 mg/1) during periods of maximum algal
blooms. Background amounts (0.1 - 0.2 mg/1)
of refractory organic nitrogen compounds were
continuously present throughout the upper Bay.
g) Meither total nor inorganic nitrogen exhibited
a clearly defined upward trend between 1968 and
1971, however, adequate data were not available
to establish the critical pre-bloom concentrations
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of these parameters during the period Dec. 1970 -
April 1971.
h) Summer concentrations of inorganic nitrogen in
the upper Chesapeake Bay showed a substantial
decrease between the Sassafras River and Bush
River. During the maximum bloom periods of 1971
a continued, but more gradual, decrease in
concentrations were observed between Bush River
and Annapolis whereas prior years with lower
bloom intensities showed a rise in inorganic
nitrogen opposite Baltimore Harbor.
i) Both maximum and average chlorophyll concentrations
measured in the upper Chesapeake Bay under summer
conditions have showed a significant rise between
1968 and 1971 as indicated in the following table:
Year Max Chloro Avg Chloro
Tyg/T)
1968 50 37
1969 50 30
1970 60 50
1971 188 100
j) During the critical bloom years of 1970 and 1971
drastic increases in chlorophyll were observed
in the Bay opposite Baltimore Harbor; maximum
chlorophyll levels persisted for approximately
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5 miles longitudinally and then decreased
sharply between the Magothy and Severn Rivers.
5) There have been subtle but important changes in the
biological conditions of the upper Chesapeake Bay area
which should be recognized and which may add support
to several conclusions drawn strictly from chemical
data.
a) Tidal portions of upper Bay tributaries such as
the Sassafras, Bohemia, Elk and Northeast Rivers
have been experiencing a change in flora which
is probably indicative of accelerated eutrophi-
cation. During the early 1960's sizeable blooms
of water chestnut and subsequently Eurasian
water milfoil were observed in these areas on
several occasions. By 1968 a succession from
green to blue-green algae had already occurred.
Extensive blue-green algal blooms composed of
Anacystis, Anabaena and Oscillatoria now inhabit
many portions of the Sassafras, Elk and Northeast
Rivers with increasing frequency, intensity
and duration.
b) The upper portions of the Bay proper including
both mesohaline and freshwater areas have recently
experienced a dramatic disappearance of the
normal rooted aquatic plants. This may have serious
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repercussions as a prelude to further adverse
biological successions. Moreover, these rooted
plants have served as a nutrient "trap" especially
in areas such as the Susquehanna flats. Without
their biological utilization of nutrients, greater
proportions of nutrients will be available to
the undesirable forms of algae if inputs remain
the same.
c) Ecological trends in the Bay's upper tributaries
have closely paralleled those documented for the
Potomac Estuary. A similar process is probably
underway in the upper Chesapeake Bay itself. Visual
observations of profuse algal blooms are being
recorded with greater frequency and persistance
and corroborate the rising trends shown by the
chlorophyll data previously presented. Of
major importance is the fact that the recent
elevated levels of chlorophyll are in part due
to increasing standing crops of undesirable
blue-green forms of algae.
While chlorophyll may not be the ideal
indicator for assessing the standing crop of
algal communities, it is nevertheless one of the
few effective tools currently available which
allows us to develop rational nutrient
limitations.
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8
6) Evaluation of pertinent data collected at each station
within the six transects indicated that maximum chlorophyll
levels were accompanied by low concentrations of inorganic
nitrogen and phosphorus. Conversely, high concentrations
of these nutrients were noted when chlorophyll levels
were relatively low.
7) Based upon a euphotic zone with a depth of 15 feet and
q 3
a total volume of 25.5 x 10 ft between transects
A and F, and the elemental composition analysis performed
on algal cells from the Potomac Estuary, the following
zonal nitrogen and phosphorus loads would theoretically
be required to yield the indicated bloom concentration,
as measured by chlorophyll a_, assuming complete utilization
by the cells and no re-cycling of the nutrients:
(ug/i)
30
40
50
100
(Ibs)
140,000
190,000
240,000
475,000
(Ibs)
500,000
650,000
800,000
1,600,000
8) Historical field data collected by AFO and the Chesapeake
Biological Institute (CBI) were utilized to estimate
nutrient losses that may have resulted from biological
uptake by the algal cells. Loading differences for
inorganic nitrogen and phosphorus measured in the
Chesapeake Bay zone between transects A and F during
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pre-bloom and peak-bloom conditions (the difference
representing nutrient uptake) are summarized in the
table below:
Inorganic Inorganic
1965*
1968
1969
1970
1971
(yg/D
40
37
30
50
100
(Ibs)
150,000
**
150,000
250,000
400,000
(Ibs)
1,400,000
1,400,000
1,000,000
1,800,000
**
* CBI data
** Inadequate data to establish pre-bloom loading
condition
9) A comparison of the data shown in the previous two tables
reveals a favorable agreement between phosphorus loads
required to yield a given bloom as estimated from
laboratory and historical field data. In the case of
nitrogen, however, loadings determined from field data
were consistently double those derived from the
laboratory elemental analysis data.
10) This over-utilization of nitrogen coupled with:
(1) the fact that measured increases in organic
nitrogen from pre-bloom to peak-bloom periods confirmed
laboratory estimates of inorganic nitrogen uptake
requirements to support such blooms and (2) the extremely
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10
low phosphorus loss rates in the upper Chesapeake Bay
as estimated by two independent methods reinforces the
argument espoused by Dr. Donald Pritchard of the
Chesapeake Bay Institute, that phosphorus was being
recycled at least twice during the algal growing season.
11) A considerable quantity of nitrogen and phosphorus data
has been collected from the Susquehanna River at
Conowingo Dam between 1969 and 1972. Several regression
analyses were performed wi.th this data in an attempt to
relate nutrient loadings with streamflow. The results
of these regression analyses, all of which were
statistically valid, are presented in the following table:
Susq
Flow TPO, Inorg P TN. Inorg N
TcTs) - ..... - ........ Ibs/day
10,000 7,500 3,500 80,000 58,000 40,000
50,000 50,000 30,000 400,000 300,000 250,000
100,000 120,000 75,000 800,000 600,000 530,000
12) Based on the above loadings it can be concluded that
the Susquehanna water was highly nitrified and that the
inorganic fractions represented an appreciable proportion
of the total nitrogen and phosphorus at all flows.
13) Regression analyses performed separately with the 1969
and 1971 total nitrogen and phosphorus data revealed
distinct loading increases for both parameters during the
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11
two year period. A comparison of these Susquehanna
loadings is given in the table below:
Flow Total Phosphorus Total Nitrogen
(cfs) (Ibs/day) (Ibs/day)
1969 1971 1969 1971
10,000 6,500 8,500 75,000 82,000
50,000 60,000 75,000 370,000 420,000
100,000 150,000 190,000 750,000 850,000
14) An attempt was made to compare predicted nutrient
loadings for Susquehanna River inputs with those
loadings actually observed in a finite volume of the
Chesapeake Bay between transects A and F during the 3 year
study period. This nutrient accountability analysis was
based upon appropriate travel and displacement times
along the upper Bay for successive parcels of Susquehanna
water. The following conclusions were drawn from this
analysis:
a) The average measured total phosphorus load was
about 400,000 Ibs whereas the average expected
load from the Susquehanna was 500,000 Ibs.
Comparable values for inorganic phosphorus were
240,000 and 280,000 Ibs respectively.
b) The average total nitrogen load measured in
the Bay was 2,000,000 Ibs whereas the average
expected load from the Susquehanna was 4,000,000
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12
Ibs. Comparable values for inorganic nitrogen
were 1,000,000 and 3,000,000 Ibs respectively.
c) The expected total phosphorus loading in the
Bay was a function of Susquehanna River flow
and varied from about 350,000 Ibs (0 6,000 cfs)
to 600,000 Ibs (@ 100,000 cfs). Inorganic
phosphorus behaved in a similar fashion, but
varied between 150,000 and 400,000 Ibs.
Comparable ranges for both parameters were
observed in the Bay during the study period.
d) The expected total and inorganic nitrogen
loadings in the Bay (4,000,000 and 3,000,000
Ibs respectively) were constant regardless of
Susquehanna flow. The increased daily loadings
during high flow periods were completely
negated by the shorter displacement times.
e) Phosphorus appears to behave more conservatively
than nitrogen on an annual basis since approximately
80-90 percent of the Susquehanna phosphorus
contribution was actually measured in the
Bay whereas less than 50 percent of the
nitrogen load was accounted for. Phosphorus
accountability exceeded 100 percent on several
occasions during the low flow summer and fall
periods and reached a minimum (65 percent) during
high flow periods. These extremes would
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13
indicate (1) the presence of an additional
phosphorus source and (2) the effects of greater
silt loads and increased phosphorus adsorption
and deposition rates generally accompanying high
flows.
15) The following table delineates average phosphorus loadings
from the Baltimore Metro Area based upon a combination
of Maryland Environmental Service (MES) data*,
information contained in the Federal industrial permit
applications, and actual sampling data:
Source Flow Total Phosphorus
TmgcT) (Ibs/day as P04)
Municipal 20 4,000
Industrial 750 35,000
Other 1,000
Totals 770 40,000
16) The following table presents a similar delineation
of total and inorganic nitrogen loadings in the
Baltimore Metro Area utilizing the same data sources:
*Published in report entitled "Water Quality Management
Plan for Patapsco and Back River Basins"
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(Ibs/day)
5,000
65,000
5,000
75,000
(Ibs/day)
3,000
54,000
3,000
60,000
14
Source Flow Total Nitrogen Inorganic Nitrogen
(mgd)
Municipal 20'
Industrial 750
Other
Totals 770
17) Water quality data collected by MES were used to eval-
uate nutrient and chlorophyll distributions in the main
channel of Baltimore Harbor during the summer growing season.
In general, the nitrogen and phosphorus concentrations
measured in the Harbor were greater than concentrations
observed in adjacent reaches of the Chesapeake Bay and
reflected the sizable loadings currently discharged from
various municipal and industrial sources. Specifically -
a) Total phosphorus concentrations in the inner Harbor
varied between 0.4 and 0.6 mg/1. The outer Harbor
exhibited relatively constant although somewhat
lower (0.25 - 0.35 mg/1) phosphorus levels.
b) Total nitrogen and inorganic nitrogen concen-
trations in the Baltimore Harbor above Sparrows
Point averaged about 1.75 mg/1 and 1.0 mg/1,
respectively. Near the mouth of the Harbor,
concentrations decreased to about 1.0 mg/1 and
0.5 mg/1, respectively.
c) Maximum chlorophyll levels (70 - 100 yg/1) were
measured between Sparrows Point and the Chesapeake
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Bay. Chlorophyll values ranging from about
60 to 80 ug/1 were measured in other portions
of the Harbor.
18) Average phosphorus concentrations found across the mouth
of Baltimore Harbor were consistently 0.04 mg/1 higher
than concentrations found in the adjacent open Bay. A
similar comparison performed for inorganic nitrogen also
indicated that concentrations at the mouth of Baltimore
Harbor were consistently higher than comparable data
from the Bay proper.
19) Considering the following - (1) that nitrogen and espe-
cially phosphorus loadings to Baltimore Harbor are quite
high, actually exceeding Susquehanna loadings to the Bay
during low flow periods, (2) a considerable body of data
shows consistently higher levels of these nutrients in
the outer Harbor than in nearby areas of the Bay, (3) the
possibility of recycling of nutrients from the grossly
contaminated bottom sediments in Baltimore Harbor and
(4) the significant exchange characteristics between the
Harbor and Bay - it appears reasonable to surmise that
the Harbor adversely affects the waters of the Bay. Any
nutrient management program undertaken for the protection of
the upper Chesapeake Bay must include adequate control not
only of discharges in the Susquehanna Basin but from the
Baltimore Metro Area as well.
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20) In order to limit the algal standing crop to 40 ug/1
chlorophyll a_, an acceptable bloom condition based upon
historical observations in the Chesapeake Bay and adopted
criteria for the Potomac Estuary, total inorganic phosphorus
and nitrogen loadings in the euphotic zone between
transects A and F should not exceed 200,000 Ibs. and
1,400,000 Ibs. respectively. Converting these loadings
to equivalent concentrations yields the following -
Phosphorus - 0.12 mg/1 as PO.
Nitrogen - 0.8 mg/1
These limiting nutrient levels were derived from
historical field data, model simulation studies and
correlations with nutrient-phytoplankton relationships
developed for the Potomac Estuary.
21) The EPA Dynamic Estuary Water Quality Model has been
adapted to the Chesapeake Bay and its tidal tributaries
upstream from Annapolis, Md. with a network comprised
of 74 junctions and 88 channels. The model proved
capable of simulating the hydrodynamic behavior of
the upper Bay as evidenced by the accurate predictions
of average tidal ranges and phasing at several USC
& GS stations.
22) A review of the available field data indicated
three steady state simulation periods with different
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17
flow and algal bloom characteristics as shown below:
Period Susq Flow Chlorophyll
(cfs) (yg/D
May - July, 1970 23,000 50
Aug - Oct, 1970 10,000 30
April - May, 1971 50,000 20
23) Salinity data collected during two of these flow
periods (10,000 and 50,000 cfs) were used to calibrate
and verify the advection and dispersion components of
the model. The model was then used to simulate total
phosphorus and inorganic nitrogen distributions for
determination of loss or uptake rates. In addition, one
simulation was made during the high bloom period in an
attempt to mathematically link chlorophyll with inorganic
nitrogen. The results of these model studies are summarized
as follows:
a) The model accurately simulated total phosphorus
during the Aug - Oct (1970) and April - May (1971)
periods when loss rates of 0.008 and 0.015/day,
respectively, were assumed. The increased rate
during the latter period probably resulted from
the greater adsorption and deposition potential
of the higher Susquehanna flow. Both rates were,
however, much lower than expected.
b) Inorganic nitrogen was also accurately simulated
on two separate occasions contingent upon the
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proper selection of uptake rates for first order
kinetics. The rates obtained from the model
(0.055 and 0.010/day) appeared to be highly
dependent upon existing chlorophyll levels.
c) For the high bloom period of 1970 and using
the uptake rate of 0.055/day for inorganic
nitrogen, the model satisfactorily simulated
the chlorophyll distribution observed in the
Chesapeake Bay. Since the model assumed an
immediate growth response corresponding to
any loss of inorganic nitrogen, phasing differences
between observed and predicted profiles did
exist; however, total masses compared
favorably.
24) Following calibration and limited verification, the
Dynamic Estuary Model was used to perform a series of
alternative runs for determining allowable total
phosphorus and inorganic nitrogen loadings from the
Susquehanna River and the Baltimore Metro Area to
achieve the previously indicated nutrient criteria
throughout the upper Chesapeake Bay. The results
obtained from these model runs for three different
Susquehanna flow conditions (10,000, 30,000 and
50,000 cfs) are presented in the tables following.
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Bait. Metro Area
20,000 Ibs/day
10,000 Ibs/day
5,000 Ibs/day
Allowable Loadings
Phosphorus (P04)
(Susq. Flow = 10,000 cfs)
Susq. Basin
3200 Ibs/day (.06 mg/1)
7000 Ibs/day (.13 mg/1)
(not a viable alternative)
(Susq. Flow = 30,000 cfs)
Bait. Metro Area
20,000 Ibs/day
10,000 Ibs/day
5,000 Ibs/day
Susq. Basin
16,000 Ibs/day (.10 mg/1)
21,500 Ibs/day (.135 mg/1)
23,000 Ibs/day (.145 mg/1)
(Susq. Flow = 50,000 cfs)
Bait. Metro Area
20,000 Ibs/day
10,000 Ibs/day
5,000 Ibs/day
Susq. Basin
35,000 Ibs/day (.13 mg/1)
36,000 Ibs/day (.135 mg/1)
38,000 Ibs/day (.14 mg/1)
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Bait. Metro Area
40,000 Ibs/day
30,000 Ibs/day
20,000 Ibs/day
Allowable Loadings
Nitrogen
(Susq. Flow = 10,000 cfs)
Susq. Basin
32,000 Ibs/day (.60 mg/1)
35,000 Ibs/day (.66 mg/1)
39,000 Ibs/day (.73 mg/1)
(Susq. Flow = 30,000 cfs)
Bait. Metro Area
40,000 Ibs/day
30,000 Ibs/day
20,000 Ibs/day
Susq. Basin
103,350 Ibs/day (.65 mg/1)
111,300 Ibs/day (.70 mg/1)
119,250 Ibs/day (.75 mg/1)
(Susq. Flow = 50,000 cfs)
Bait. Metro Area
40,000 Ibs/day
30,000 Ibs/day
20,000 Ibs/day
Susq. Basin
186,000 Ibs/day (.69 mg/1)
194,000 Ibs/day (.72 mg/1)
200,000 Ibs/day (.75 mg/1)
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It should be noted that the Baltimore loadings were not
predicated on the protection of Baltimore Harbor waters,
otherwise more stringent loadings would probably have
been required.
25) In view of the uncertainty in defining the various
reactions responsible for conversion of organic forms
of phosphorus to inorganic forms (and vice versa);
the almost immediate utilization of regenerated phosphorus
by phytoplankton as hypothesized by Dr. Pritchard and
somewhat substantiated by data presented in this
report; and the low apparent loss rate for phosphorus,
allowable phosphorus loadings from the Susquehanna Basin
and the Baltimore area were developed for total and
not inorganic phosphorus.
26) Inorganic nitrogen was treated as a conservative
parameter in all of the model production runs. Since
the criteria, hence the allowable loadings, apply
primarily during pre-bloom periods this appeared to be
a reasonable assumption.
27) There was insufficient field data available to calibrate
or verify adequately the mathematical model for a
Susquehanna River flow of 100,000 cfs and the effects
of this extreme flow condition on the nutrient distri-
bution in the upper Chesapeake Bay could not be
properly evaluated.
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22
28) Special model runs were prepared to investigate the
effects of the Sandy Point STP discharge on the
phosphorus concentrations in nearby areas of the
Chesapeake Bay. Assuming present plant design capacity
(4.2 mgd - wastewater flow; 40,000 - population served)
and the realization of adequate phosphorus control in the
Susquehanna Basin and the Baltimore area, the model runs
demonstrated that the effects of the Sandy Point STP
discharge would be minor and the phosphorus criteria in the
Chesapeake Bay could still be achieved for either Susquehanna
River flow. Any future expansion of this facility,
however, would require a thorough investigation to determine
the necessity for and extent of nutrient removal.
29) As stated previously, it is quite possible that inorganic
nitrogen is presently the rate-limiting nutrient in the
upper Chesapeake Bay, however, it is reasonable to
expect that phosphorus can be made the rate-limiting
nutrient if adequate control measures are instituted.
Phosphorus is more manageable in the Susquehanna Basin
than nitrogen, especially during higher flow periods.
Nitrogen control may be a feasible alternative under
normal dry weather conditions, but concentrated slugs of
nitrogen occurrina from natural runoff durina short-term
localized storms would probably cause the maximum
allowable nitrogen concentrations previously established
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23
to be exceeded during the long retention periods
resulting from slow net seaward transport.
30) A mass balance analysis was performed on all nutrient
data collected in the lower Susquehanna Basin from
June 1971 to June 1972. The results obtained from
this analysis were used to estimate the degree of
controllability of nitrogen and phosphorus during
various seasons and flow conditions. For the three
Susquehanna flows investigated, the following tables
depict the effects of different reductions of all point
source discharges on the river loadings at Conowingo:
Est. Total Est. Inorganic
% Reduction Phosphorus Load Nitrogen Load
(Ibs/day)(Ibs/day)
10.000 cfs
0 8,300 57,000
50 5,700 53,000
70 4,600 50,000
90 3,800 47,000
30.000 cfs
0 27,100 187,500
50 23,000 183,500
70 21,500 182,500
90 20,000 180,000
50,000 cfs
0 46,000 309,000
50 41,000 305,000
70 40,000 303,000
90 38,500 301,000
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24
31) Assuming sustained Susquehanna River flows of 10,000
and 30,000 cfs and utilizing the previous two tables,
a reduction in the existing phosphorus load from both
the point source discharges in the lower Susquehanna
Basin and the Baltimore area of 70 percent will be
required to achieve the 0.12 mg/1 total phosphorus
concentration limit in the Chesapeake Bay. If a
sustained flow of 50,000 cfs is assumed, it is
doubtful whether this criteria can be attained
unless over a 90 percent reduction at each of the
point source discharges in the lower Susquehanna
Basin and the Baltimore area is realized. It is
important to recognize that the Susquehanna River
becomes increasingly significant in terms of a
phosphorus management program during higher flow
periods, especially for protection of the extreme
upper reaches of the Bay. Unfortunately, the
controllable percentage of the phosphorus load in
the Susquehanna Basin decreases dramatically for
such flow periods.
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APPENDIX
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UPPER CHESAPEAKE BAY
CONOWINGO
DAM
Al SAMPLING STATION
BALTIMORE
ANNAPOLIS
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HYDROGRAPH
SUSQUEHANNA RIVER AT CONOWINGO DAM
( 1968- 1971)
150
140
130
120
10
100
90
80
70
60
50
40
30
20
10
u1
r
1
53ISM
1968
1969
1970
I97I
-------
CROSS SECTIONAL AREAS
UPPER CHESAPEAKE BAY
(CBI DATA)
o
LU
QC
100 -
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 H
10 -
A
I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 2 4 6 8 10 12 14 'P 18 2r 22 24 26 28 3C 32 34 36
MILES BELOV SUSQ.RIVER
-------
ADVECTIVE VELOCITIES vs. SUSQUEHANNA RIVER FLOW
UPPER CHESAPEAKE BAY
O
O
e. u -
18 -
16 -
~. l4 ~
u
<
12 -
1-
O
q
d '0 -
UJ
g 0.8 -
h-
u
UJ
0
< 06 -
04 -
02 -
00 -
O
20QOOOcfs
lOQOOOcfs
75,000efs
50,000 eft
30,000 efs
10000 cfs
O
0
O
c>
0
O
O
O
?
oo
O
1 1 1 1 I 1 I I I I 1 1 1 1 1 1
02 46 8 10 12 14 16 18 20 22 24 26 28 30 32
MILES BELOW SUSQUEHANNA RIVER
-------
TRAVEL TIMES vs. SUSQUEHANNA RIVER FLOW
UPPER CHESAPEAKE BAY
i
UJ
120 -
no -
100 -
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
28 30 32 34 36
10 12 14 16 18 20 22
MILES BELOW SUSQ. RIVER
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT A
{AVERAGE DATA FOR TRANSECT)
1.50
1.40
1.30
1.20
1.10
1.00
.90
.80
.70
.60
.50
.40
.30
.20
.10
0
LEGEND
Pi
I I I I I I I I I I
1971
n
1968
11111 M 1111
1969
T
iS3£55^32i5Sti
iu-S^S-iT^ulOZQ
-. M 5 ? a z
< b> < i < 3
-) b. 2 < S ->
1970
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT B
(AVERAGE DATA FOR TRANSECT)
o>
e
I 50 |
1.40 '
I 30 -
1.20 -
1.10 -
1.00 -
90
80
.70
.60
.50
.40 -
.30
.20 -
.10
LEGEND
TP04
p,
zoj<*o:>ziOQ.*~:>u
-><OZa
1968
I II II II I I II
1969
u < a. <
> u. 2 < 2
>Z_i(3Q.t->u
'DDDUJUOUJ
-i -> <
< CL <
iu Z < I
1970
1971
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT C
(AVERAGE DATA FOR TRANSECT)
1.50
1.40 -
1.30 -
1.20
1. 10
1.00
.90
o>
.80
.70
.60
.50
.40 -
.30
.20
.10
LEGEND
TPO4
Pi
JKs
-> u. 2 < 2 -> => « Ho
1968
1969
1970
< S 5 a S 3 => 3>" y o
--
1971
Z Z
< uj < Q. < D
-1 u. Z < 2 ->
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT D
(AVERAGE DATA FOR TRANSECT)
1.50
1.40 -
1.30 -
1.20
1.10 -
1.00 -
.90
.80 -
.70
.60
.50
.40 -
.30
.20 -
.10
LEGEND
TP04
Pi
ZcoQ:cr>z_jOaf->L>
->tf S4S->->
3 £ Z < Z
-> -> < 5?5Z-iOo;J->u
1970
zim 25 oe>; 2
u. Z < Z ->
1971
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT E
(AVERAGE DATA FOR TRANSECT)
1.50 I
140
1.30
1.20
1.10
1.00
.90
.80
en
E
.70
.60
.50
.40
.30
.20
10
LEGEND
TP04
Pi
TT
Z O> "^ 0: > 2 -J G Q- *~ > U
-> u. Z < Z -> -i < t/1 O Z O
1968
i o o i
i O Z Q ^ u.
ZCD 5 a > 2
< w 2 a 5 D
-> u. s < 2 -,
1969
1970
1971
-------
TEMPORAL PHOSPHORUS DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT F
(AVERAGE DATA FOR TRANSECT)
1.50
1.40
1.30
1.20
1.10
.00
.90
en
6
.80
.70
.60
.50
.40 i
.30 I
.20 '
.10 ^
LEGEND
TP04
P,
1968
Zala:C£>z_iOa.>->o
u.ZOza
1969
Za>z-i!=>a.'->u
ujUOW
~>u.Z=!<«iozo
1971
Z a " K i 2
< uj < o.< D
-> u. Z < Z ->
-------
TOTAL PHOSPHORUS CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA FOR ALL TRANSECTS)
.40 -i
.36 -
.32 -
.28 -
S
df
Q.
I- .16 H
12 -
.08 -
.04 -
.00
z' a> 2 ? S :
< ui < CL < :
u. I < 2
1968
1969
S~><*nO2o
1970
i a i- > o
> UI U O UI
!
-------
INORGANIC PHOSPHORUS CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA FOR ALL TRANSECTS)
40 -i
.36 -
.32 -
.28 -
-.24-
O
a
3 .20 -
.16 H
.12 -
08 -
.04 -
.00
1968
->il5-><>nO±a
1969
1970
1971
z o 5 a: % z
T u! 2 « * T
-------
SPATIAL PHOSPHORUS DISTRIBUTIONS
UPPER CHESAPEAKE BAY
JULY -SEPT, 1969
JULY . 1970
JULY - AUG. , 1971
.3 -
en
E
o
a
.2 -
-I- -1- -I- -1- -T-
12 16 20 24 28
MILES BELOW SUSQ. RIVER
T~
32
T
4
-r
8
36
40
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT A
(AVERAGE DATA FOR TRANSECT)
en
E
150
140 -
1.30 -
1.20
1.10 -
1.00 -
.90
.80
.70
.60
.50
40 -
.30
.20
.10
LEGEND
NO2+ N03
NH3
1968
- -
. 2 < 2->->u.Z->u
UO u
Zaio; a: > z
< uj < Q. < D
-i u. Z < 2 ->
1971
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT B
(AVERAGE DATA FOR TRANSECT)
1.50 I
1.40
30
1.20
1.10
1.00
.90
.80
o>
£
.70
.60
.50
.40
.30
20
10
LEGEND
TKN
NH3
NO
5S$2;Sl^S;o§t!
-^!l-vz_ii;)a-(->u
[o.<*)D^ujoOui
: O
) u} U O ui
! i/l O Z O
< w
-> u. Z <
1970
1971
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT C
(AVERAGE DATA FOR TRANSECT)
1.50 I
1.40
1.30
1.20
1.10
1.00
.90
.80
.70
.60
50
.40
.30
.20
10
0
LEGEND
TKN
N0
NH3
> o
i a
z'z-iOo:t->
O u
~
± m a: ir > z
< u < Q. < D
->£ Z < Z -i
1968
1969
1970
1971
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT D
(AVERAGE DATA FOR TRANSECT)
1.50 I
1.40
1.30
1.20
.10
1.00
.90
.80
.70
.60
.50
.40
.30
.20
.10
LEGEND
TKN
NO2 + NO3
NH3
1968
3 z 3 § u o o u
E T -> < I/i o zo
1969
1970
1971
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT E
(AVERAGE DATA FOR TRANSECT)
1.50
1.40
1.30
1.20
1.10
1.00
.90
.80
.70 I
.60
50
.40
.30
.20
.10
LEGEND
TKN
NO2+ NO3
NH3
_ ^
> < K1 O Z O
MINIMI
.
-) u. 2 < 2
£ > o
i o z o
TTTTTT
z oi a: cr > z
u. Z < 2 -i
1966
1969
1970
1971
-------
TEMPORAL NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
TRANSECT F
(AVERAGE DATA FOR TRANSECT)
.50 I
1.40
1.30
1.20
1.10
1.00
.90
N.
(T>
.80
.70
.60
.50
.40
.30
.20
.10
LEGEND
TKN
NO2 + NO3
NH3
TTT1 MINT
|B5£5|^3£GSti
->u.3u.3<3->-> i)
3 UJ O O uj
< 1/1 o z o
z a> a tf > 2
< UJ < 0- "^ 3
TU. 3 <3 -.
1970
1971
-------
TOTAL NITROGEN CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA)
1.50
1.40 -
1.30
1.20
1.10
1.00
.90
.80
S.
E .70
.60
.50
.40 -
.30
.20
.10 -
z o
<« u:
1968
1969
1970
i a i- > o
i ui U O Ul
: m o z a
Z m "j K > z
< u < a. < 3
T u. Z < 2 ->
1971
-------
INORGANIC NITROGEN CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA)
1.50 i
1.40
1.30
1.20
1.10
N
1.00
.90
.80
.70
.60
.50
.40
.30
.20
JO
I I M M
. _j O a t- >
TTT
irar>z_,Oa.i-> o
< m o
O u
Z 0
2 m 5 n
< ui < i
< S < o- < 3
T u! z < z -i
1969
1970
1971
-------
s
en
1.50 -
1.40
1.30
1.20 -
1.10 -
1.00 -
.90 -
.80
.70
.60
.50
.40 -
.30 -
.20
.10 -
TOTAL KJELDAHL NITROGEN CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA)
ZajJ^JZjOa^gU
-> u? 3<2->-»<OZa
1968
1 1 1 1 1
1 1 1 1 1
_i ^ °- " >O
D^UJU Ouj
-i<'flO zo
1969
1 ] 1 1 1 ]
19^0
1971
-------
AMMONIA NITROGEN CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA)
1.0 -i
.9 -
.8 -
.7 -
.6 -
.5-
.4 -
.3-
.2 -
0
t > z 5 o > o
1 1
rf UJ 4 ^ 4 -^
1968
1969
1970
1971
-------
1.50 i
1.40
1.30
1.20
MO
1.00
.90
NITRATE NITROGEN CONCENTRATIONS
UPPER CHESAPEAKE BAY
(AVERAGE DATA)
N
en
E
.80
.70
.60
.50
.40
.30
.20
.10
0
Z a> S ? 5 z -" 2<* ^ £ U
1968
Zo><£cr>z_ioli:i"; > o
SUJL) OUJ
1969
: I- > o
I O O Ld
i O z o
1970
1971
zm 5 a > z
^ UJ ^ " ^ D
nil X <« XT
-------
SPATIAL INORGANIC NITROGEN DISTRIBUTION
UPPER CHESAPEAKE BAY
JUNE - SEPT, 1969
JULY, 1970
JUNE - AUG. 1971
.6 -
(71
E
o
cr
O
.4 -
.2 -
I
40
~T
8
~r~ ~~r~ ~~r~ ~r~
12 16 20 24
MILES BELOW SUSQ. RIVER
~T~
28
r~
32
36
-------
CHLOROPHYLL a. CONCENTRATIONS
0>
150
140
130
120
II 0
100
90
80
70
60 -
50
40
30
20
10
o
I 1 .1 I I I I IJ I
1968
I I I I I I I 1 .1 I I
1969
1970
:«>-zj«£l">o
; a. < D o^ujU o»*j
; < z -» -> < *« o z o
1971
z m « oc >
< Ul
-------
140 -i
SPATIAL CHLOROPHYLL DISTRIBUTION
UPPER CHESAPEAKE BAY
120 -
JUNE - SEPT. 1969
JULY, 1970
JUNE - AUG , 1971
100 -
x
80 -
o
cc
o
_J
I
o
60 -
40 -
20 -
r~
32 36
T
4
8
T- -i- T~ ~T-
12 16 20 24
MILES BELOW SUSQ. RIVER
28
40
-------
180-1
170-
160-
150-
140-
130-
120 -
N.
S4 no-
I
°l 100-
> 90-
I
Q.
O 80-
cr
O
I
u
60-
50-
40-
30-
20-
10-
o-
INORGANIC PHOSPHORUS vs CHLOROPHYLL a
UPPER CHESAPEAKE BAY
(1969-1971 TRANSECT DATA)
T^T-^T^T-^T T ~r T
.02 .04 .06 .08 .10 .12 .14 .16
INORGANIC PHOSPHORUS - mg/l
IB
.20
.22
24
-------
180-
170 -
160-
150-
140 -
130-
120-
\
? 110-
i
°'ioo -
_l
^9
I
O 80-
cr
O
- 70-
U
60 -
50-
40-
30 -
20-
10 -
0
INORGANIC NITROGEN vs CHLOROPHYLL a.
UPPER CHESAPEAKE BAY
(1969-1971 TRANSECT DATA)
-r~r~~r~r~T~^~r~^~r~r~T~ ~r ~r
.08 16 .24 .32 .40 48 .56 .64
INORGANIC NITROGEN - mg/l
72
.80
.88
.96
-------
PHOSPHORUS AND NITROGEN LOADINGS
UPPER CHESAPEAKE BAY
BETWEEN TRANSECTS A & F
(volume = 45 x I09 ft3)
TOTAL NITROGEN
INORGANIC NITROGEN
TOTAL PHOSPHORUS (asPO4)
INORGANIC PHOSPHORUS ( as P04)
CO
o
4000 -
3600 -
3200 -
2800 -
2400
2000 -
1600 -
1200 -
800 -
400 -
I I I I I I I I I I I I I I I M I I I I I I
z «
< UJ
-
I I I I I I I I
I I I I I I I I I I I I I I I I I I
| a. i- > Olz «B« u. Z <
i o z o
Z»$«$Z
S! z < z T
1968
1969
1970
1971
-------
100-
80-
60-
40-
20-
TEMPORAL PHOSPHORUS and CHLOROPHYLL TRENDS
CHESAPEAKE BAY BETWEEN TRANSECTS A and F
(CBI and AFO DATA)
TOTAL P (as PO4)
INORG P (as PO4)
CHLOROPHYLL a
.2-
.15-
.05-
\/
11111111111111111 1111 111 11) 1111111111111 111111111111 11111111 1111111111111
|isiilli!l*l#8iS!li3igii*fS^
1966 1967 1868 1969 1970 1971
I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I
I | | I I I I I I I I
1950
1951
1064
1965
-------
120-1
100-
80-
o> 60-
1
40-
20-
TEMPORAL NITROGEN and CHLOROPHYLL TRENDS
CHESAPEAKE BAY BETWEEN TRANSECTS A and F
(CBI and AFO DATA)
NO2+ NO3 (asN)
INORG N (asN)
CHLOROPHYLL a
.80-
.60-
.40-
.20-
I 950
1951
I 964
I I I I I I I I I I I
1965
1966
1967
1968
>-i*Oat-'>"ll-«I'«>-l!l1'a|-'>o
Sl?3B8!a5es!sl?il8lg
1970 1971
-------
0
NUTRIENT- CHLOROPHYLL RELATIONSHIPS
UPPER CHESAPEAKE BAY
0 LAB DATA /INORGANIC
X FIELD DATA N & P
_D DATA- ORGANIC N
ASSUMPTIONS:
I. EUPHOTIC DEPTH = 15 ft. (25.5 x I09H3)
2. .045 MG C/ug CHLORO RATIOS:
3. .010 MG N/>jg CHLORO
4. .003 MG PO4 /ug CHLORO
10
20
30
120
CHLOROPHYLL a
-------
REGRESSION ANALYSIS
TOTAL PHOSPHORUS LOAD vs FLOW
SUSQUEHANNA RIVER at CONOWINGO
(1969-72 DATA)
1000.000 -i
100.000-
IB
-0
I
-t
o
a
10.000-
\JOOO -\
1,000
CORRELATION
»-- 28.10**
D. F. -- 95
COEF. r 0.94
1 I
10.000
100.000
1 ' I
IX)00.000
FLOW - cfs
-------
REGRESSION ANALYSIS
INORGANIC PHOSPHORUS LOAD vs FLOW
SUSQUEHANNA RIVER at CONOWINGO
(1969-72 DATA)
i .000,000 ^
100.000-
-a 10.000
I
CL
1.000-
CORRELATION COEF. r 0.89
I -- 18.78**
D. F. - 90
100'
1.000,000
I1
100.000 10.000
FLOW - cfs
1,000
-------
REGRESSION ANALYSIS
TOTAL NITROGEN LOAD vs FLOW
SUSQUEHANNA RIVER AT CONOWINGO, MARYLAND
(1969-1972 DATA)
10,000,000 -i
1,000,000 -
5-
I
z
100,000 -
10,000
CORRELATION COEF. = 0.96
t = 31.60* '
D.F = 90
IjOOO
I I I I I ~T
10,000
1I I I I I I
100,000
T 1 1
500,000
FLOW - cfs
-------
REGRESSION ANALYSIS
TOTAL INORGANIC NITROGEN LOAD vs FLOW
SUSQUEHANNA RIVER AT CONOWINGO, MARYLAND
(1969-1972 DATA)
10,000,000 -i
IjOOO.OOO -
100,000 -
10,000
CORRELATION COEF. = 0.95
t = 28.52* '
D.F = 87
i r
IjOOO
II I I I
10,000
I I I I I I
100,000
500,000
FLOW -cfs
-------
REGRESSION ANALYSIS
TOTAL KJELDAHL NITROGEN LOAD vs FLOW
SUSQUEHANNA RIVER AT CONOWINGO, MARYLAND
(1969-1972 DATA)
10,000,000 -i
1,000,000 -
n
-Q
100,000 -
10,000
CORRELATION COEF = 0.86
t = 16.47' *
D.F. - 94
1,000
10,000
I I i
i
100,000
SOOjOOO
FLOW -cfs
-------
REGRESSION ANALYSIS
NITRATE NITROGEN LOAD vs FLOW
SUSQUEHANNA RIVER AT CONOWINGO, MARYLAND
(1969-1972 DATA)
10,000,000 -i
1,000,000 -
O
Z
100,000 -
10,000
1,000
CORRELATION COEF. - 0.93
t = 23.54**
D.F = 91
1 I I I II
10,000
1 1 I I I I I
100,000
-II
500,000
FLOW - cfs
-------
REGRESSION ANALYSIS
TOTAL PHOSPHORUS LOAD VS FLOW
SUSQUEHANNA RIVER a* CONOWINGO
( 1969 and 1971 DATA)
1,000,000 -i
100.000 -
X
a
-o
«0
-O
o
a
10.000 -
1.000
1969 DATA
Correlation Coef =0.98
"t" = 23.42 **
D. F. = 27
1971 DATA
Correlation Cocf = 0.90
"I" = 8.94 * *
D. F. = 21
(1969 DATA)
1,000
-IIIII]
10,000
-i F r
100,000
I.OOO.OC
FLOW- cfs
-------
REGRESSION ANALYSIS
TOTAL NITROGEN LOAD VS FLOW
SUSQUEHANNA RIVER a* CONOWINGO
(1969 and 1971 DATA)
10000000-1
1000.000 -
X
a
100.000-
10.000-
1969 DATA
Correlation Cotf = 0.93
"»" = 11.80 '*
D. F. = 24
1971 DATA
Correlation Cotf
"»" = 6.72
D. F. = 21
1.000
~n
\ojaoo
(1969 DATA)
-ii» i i
100.000
ijooaooo
FLOW- cfs
-------
MILES BELOW SUSQUEHANNA RIVER
I TRANSECTS I
6 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 20 DATE
i 1 1 1 i i ill i __l 1 1 1 1 L_
OEC, 1967
JAN 1-31 (I8,000cf>)
JAN 1-31 (IftOOOcfi
FEB 2- 6 IIOQOOOch)
ceo 7
FEB 2-6 (lOaOOOcl.) t(^Q
JAN 1-31 (laOOOcf.)
FEB 2-6 IIOQOOOcd)
FEB 2-6 (IOO.OOOcf.1 FEB 7-11 ISQOOOcf.)
rsaoJol', rEB,2-29(,aooocf,,
-II FEB 12-29 MAR 1-18 (IBflOOcM
cfs) (I8,000cfil
MAR 19-31 (lOOOOOcftl
MARI9-3I (I00,000cf»
APRIL 1-12 (50,000c(s)
APRIL 13-MAY 13 (2QOOOcd)
MAY 14 - 28 (60,000e<>)
JUNE 7 -JULY
APRILI-12 (SaOOOcfi)
APRIL 13 -MAY 13 (2QOOOc(i)
MAYI4-28BQOOOc(5)
MAY 29 -JUNE 6 (100.000 cfO
JUNE 7 -JULY 6 (40.000 cfi)
6 (40DOOcftl JULY 7-31 02POOef»)
1/31/68
2/6/68
2/11/68
2/29/68
3/18/68
3/31/68
4/12/68
5/13/68
5/28/68
6/6/68
7/6/68
7/31/68
m
r~
§
m
C H
8 °
m (/>
O
- O
(O
m
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MILES BELOW SUSQUEHANNA RIVER
TRANSECTS _.__
36 34 32 30 28 26 24 22 20 IB 16 14 12 10 8 6 4 20 LtfML
SEPT 1-30 IKOOOcW
ii 1 1 1 1 1 1 1 1 1 L
JUNE 7 - JULY 6 (4Q000cfi)
JULY 7-3l02000c(i) AUG 1 - 31 (6000cfi)
JUNE 7- JULYS WQDOOcfJ
JULY 7-31 AUGI-31
SEPT 1-30 04000eW
JUNE 7- JULY 6
(40.000 cfi)
JULY7-3I AUGI-31
ll2jQOOif.l|l5000cM
SEPT l-30(l4,OOOcM
OCT 1-31 (7XX30cf.l
JULY 7-31
(I2.000c(»)
AUGI-31
BOOOcfi)
SEPT 1-31 I OCTI-31
(I4.000efi) I TOOOcM |
NOV 1-18 (20.000cf»)
NOV 19-22 (lOOjOOOch)
NOV 19 -22
1100,000 cf»)
NOV 23 -DEC 15 (45.000 eU)
NOV 23- DEC 15
(45.000 cfi)
DEC 16- JAN 31 (20,000 cdl
DECI6-JAN3I (20jOOOcfs)
FEB 1-12 (40,000cf»l
OECI6-JAN3I
( 20.000 eh)
FEB 1-12 (40.000cfs)
FEB 13-MARCH 23 (15,000 cdl
FEB 1-12
(40,000 cfi)
FEB 13 -MARCH 23
(15.000 cfi)
MARCH 24-31 (TCtOOOcfs)
FEB 13 - MARCH 23(l5jOOOefi) MARCH 24-31 (70,000cf»)
APRIL 1 - 6 (4QOOOcU )
MARCH 24 -31 (TQOOOcfi)
APRIL 1-6
APRIL 7-10 (95.000cf»)
8/31/68
9/30/68
10/31/68
11/18/68
M/22/6B
13/15/68
2/12/69
3/23/69
3/31/69
4/6/69
4/10/69
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MILES BELOW SUSQUEHANNA RIVER
36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 DATE
i i i i i i i i i i i i i I i i i
APRIL 7-10
(95,000 cf»)
APRIL 11-30 (SO.OOOcfi)
APRIL II -30
(50,000 cd)
MAY 1 - 31 (33.000cdl
MAY 1-31 !33,OOOcW
JUNE 1 -30 (IftOOOcfi)
MAY 1-31 (33,000cfs) JUNE I-30 (l9DOOcfi)
JULY 1-22 OOOOOcfi)
JUNE 1-30 (IQOOOcfi)
JULY 1-22
(10,000 cfi)
JULY 23 - AUG 10 (28.000 .( )
JUNE 1-30 JULY 1-22
1 19,000 ch) (lOQOOcfs)
JULY 23-AUG 10 (28,000 c
AUG 11-31 (I3.000cfi)
JULY 1-22
(IO.OOOA)
JULY 23-AUG 10 I28,000cf>)
AUG II -31 (I3,000c(»)
SEPT 1-31 (6,000cf»)
JULY 23 - AUG 10 (28,000cfi)
OCTLNOV8 (6.000c,,.
AUG 11-31
(13,000 cW
SEPTI-3l|OClN08
(6000ti
NOV9-3I OaOOOeW
AUG 11-31
(3,000 ch)
SEPI-3IOCI
I6j000c« ;6,
NOV 9-31 UO.OOOcfi)
DEC 1 - 10 I IB.OOOcfj)
NOV 9 -31 (30flOOcf.)
DEC ll-22(50XX)OcM
OECII-22(50,OOOcfi)
DEC23-FEB2(20^00cf»)
4/31/69
5/31/69
6/31/69
7/22/69
8/10/69
/ /
8/31/69
9/3,/69
11/8/69
11/31/69
12/10/69
12/22/69
2/2/70
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MILES BELOW SUSQUEHANNA RIVER
36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 DATE
1 1 1 1 1
1 1 1 1 1 I 1 1 1 1 1 1
DEC23-FEB2
(20.000 cfi)
FEB 3-14 (lOOjOOOcfi)
FEB 15-28
(40.000 cfil
FEB 3 -14 (lOOjOOOcf.)
FEB l5-28(40,000cfi)
MAR 1 -27 (40.000cf>)
MAR28-APRILI9 (ISO.OOOcft)
MARCH 28 - APRIL 19
(150.000 cfil
APRIL 20-31 (BSOOOcli)
MAY 1-15(40000
MAY 16-31 (40.00C
JUNE 1-30(20000
JUNE l-30(2QOOOch) JUL
JUNE 1-30 I-3II20C
(20,OOOcM JULY ' 3l(2a°
JULY 1 -31 (20.000cfi
APR 20-31 (88,000cfi)
MAY l-l5(40000cfi)
cM MAY l6-3l(40jOOOcf»)
cfj JUNE 1 -30 (20.000cfs)
cfi) JUUT 1 -31 (20,000 cfi)
Y -31 <20.000cf>) AUG 1-31 UOjOOOcM
00 cb) AUG 1 -31 liaOOOchl SEPT 1 -30 (ftOOOchl
) *!oflOOc«' SEPT ' -3° (&.000ef »l OCT 1-15 (8,000 cfil
2/14/70
2/28/70
3/27/70
4/19/70
4/31/70
5/15/70
5/31/70
6/30/70
7/31/70
8/31/70
9/30/70
10/15/70
m
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MILES BELOW SUSQUEHANNA RIVER
6 34 32 30 28 26
24 22 20 18 16 14 12 10 8 6 4 2 0
i i i i I I I 1 1 J L
(XT l-l5(6jOOOcf>)
AUG 1-31 SEP 1-30 j
(10,000 M BjDOOril
OCTI6- NOV 13 I30.000cfi)
NOV l4-22(IOO,OOOcf>)
NOV 23 - DEC 13 (40,000cfi)
DEC 14 -31 (ASOOOcf
DEC 14-31
,45.000 cf,, JAN1-'7
JAN 1-17 JAN 18 -
(35)000 eft ) (18,001
OCT 16 -NOV 13 I30,000cli)
NOV '14 - 22 (lOO.OOOcfi)
NOV 23 -DEC 13 (AO.OOOcd)
1 DEC 14-31 (45£00cfi>
>) JAN 1-17 (35jOOOcl>)
(35000c(>) JANI8-FEBI3 (I8,000cfsl
rEB l3 FEB !4-2l(80X)OOeft)
)cfs)
FEB2I-MAR6 (I60,000cf.)
FEB2I - MAR 6 (160000
f,) MAR 7-16 <70,000cf.)
MAR 17- 23(135 ,000cf»)
-
MAR 17-23 (I35OOOC
f,| MAR 23 -APR 4 (50,000c(»)
APR 5-20 leOOOOcfil
DATE
11/13/70
11/22/70
12/13/70
12/31/70
1/17/71
2/13/71
2/21/71
3/6/71
3/16/71
3/23/71
4/4/71
4/20/71
33
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MILES BELOW SUSQUEHANNA RIVER
16 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 42 0
, i i i i i 1 1 1 1
APR 5-20(80,OOOcf.)
APR 20 -MAY 8 (40,000cfs)
APR 20 -MAY 8 MA₯g_|9
(40jOOOcf»)
MAY 9 -19 (60.000 c(») "35000
MAY 9-19 MAY 20-31
BQOOOcf.) (35.000efjJ
MAY 20-31 JUNE 1-2
(35/DOOcf.) (ISiQOOef.)
MAY 20-31 JUNE 1 -30 JULY 1
135000*1 Il5,000cfs) (7500
JUNE 1-30 JUiyi-3l| AUGI
( 15,000 ef») <7500cw| (25.OCK
JUNEH30 JULY 1-31 AUG 1-10 AUG
(I5000A) fTSOOcfs) (25000cft) (BO
AUG M-SPI4J SEPT 15-30 OCT 1-2
(SjDOOcM 1 IIAjOOOcW (9XX»c(
SEPTI5-30 OCT 1-261
(I4j000ch) (9jOOOch) |
APR 21 - MAY 8 (40.000c(.)
MAY 9-19 (60,000cf>)
OOcfi) MAY 20-31 (35jOOOcf»)
~31 JUNE 1-30 (ISjOOOef.)
JUNE l-30«5000ef») JULY 1-31 (7.500eftl
0 JULY 1-31 AUGI-IO(25jOOOef»)
CZ500cfid
31 AUG 1 - 10
AUG||_SEpT|4 (^QQjf,)
:f»l I25000cfi)
-10 AUG II -SEPT 14 SEPTI5-30(>4,OOOA)
MI) laooocdi
II-SPM SEPT ,5 -30 OCT 1-26 MOOO.W
OOcb) (I4,000cl.)
* OCT27-NOV29(l7X)OOcfi)
>)
MOV 29 (I7,000cf.) NOV 30- DEC 7 1 35COO cfs)
NOV30-DEC7
(35,000 ef>)
DEC 8-l6(l05,OOOcf>)
DATE
5/8/71
5/19/71
5/31/71
6/30/71
7/31/71
8/10/71
9/14/71
9/30/71
10/26/71
11/29/71
12/7/71
12/16/71
m
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-------
PHOSPHORUS RELATIONSHIPS
SUSQUEHANNA RIVER - CHESAPEAKE BAY
Date
04/22/68
05/22/68
06/24/68
07/09/68
09/04/68
10/23/68
12/04/68
03/06/69
05/22/69
06/18/69
07/09/69
09/03/69
12/17/69
02/18/70
03/30/70
05/20/70
06/11/70
07/07/70
08/10/70
10/06/70
11/11/70
04/19/71
05/17/71
06/16/71
07/13/71
08/17/71
10/13/71
CHESAPEAKE BAY BETWEEN TRANSECTS A & F
(45 x 10* ft3)
SUSQUEHANNA RIVER AT CONOWINGO
TP
(mg/1)
.09
. 09
. 11
. 11
. 10
. 13
.09
.12
.09
. 14
. 17
. 20
.13
.16
. 15
. 11
. 14
. 17
. 20
. 23
.17
.10
.14
. 14
.21
. 20
. 21
TP
(103 Ibs)
252.7
252.7
308.9
308.9
280.9
365.0
252.7
337.0
252.7
393.1
477.4
561.6
365.0
449.3
421.2
308.9
393.1
477.4
561.6
645.8
477.4
280.9
393.1
393.1
589.7
561.6
589.7
Approximate Averages: 400
Approx Av (Feb-June): 340
Approx Av (July-Dec): 460
Approximate Ranges: 250-600
Pi
(mg/1)
Pi
(103 Ibs)
.06
.08
.12
.13
.05
.03
.08
.08
.14
.18
.15
.05
.04
.04
.07
.06
.09
168.5
224.6
337.0
365.0
140.4
84.2
224.6
224.6
393.1
505.4
421.2
140.4
112.3
112.3
196.6
168.5
252.7
240
170
290
100-500
Flow at
Conowingo*
(cfs)
100,000
50,000
100,000
70 ,000
40,000
40,000
20 ,000
20,000
50 ,000
40 ,000
33,000
19,000
6,000
100,000
40 ,000
88,000
40,000
40,000
20,000
20,000
10,000
80 ,000
60,000
50,000
60,000
35,000
15,000
45,000
60 ,000
30 ,000
Days
Required to
Fill Volume
(45 x 109 ft3)
5.2
10.4
5.2
7.6
13.0
13.0
26.0
26.0
10.4
13.0
15.8
27.4
86.8
5.2
13.0
5.9
13.0
13.0
26.0
26.0
52.1
6.5
8.7
10.4
8.7
14.9
34.7
Daily TP
Load at
Conowingo
(Ibs/day)
117,000
50 ,000
1 1 7 ,000
76 ,000
39 ,000
39 ,000
1 7 ,000
1 7 ,000
50 ,000
39 ,000
31 ,000
16,000
4,000
1 1 7 ,000
39 ,000
100,000
39 ,000
39 ,000
17,000
1 7 ,000
7,500
90,000
63,000
50,000
63,000
33,000
12,000
Expected
TP Load in
Volume
(103 Ibs)
608.4
520.0
608.4
577.6
507.0
507.0
442.0
442.0
520.0
507.0
489.8
438.4
347.2
608.4
507.0
590.0
507.0
507.0
442.0
442.0
390.8
585.0
548.1
520.0
548.1
491.7
416.4
500
540
470
Daily Pi
Load at
Conowingo
(Ibs/day)
17,000
8,100
1,700
75,000
22,000
63,000
22 ,000
22 ,000
8,700
8,700
3,400
56 ,000
38,000
30 ,000
38,000
18,000
5,900
Expected
Pi Load
in Volume
(103 Ibs)
268.6
221.9
147.6
390.0
286.0
371.7
286.0
286.0
226.2
226.2
177.1
364.0
330.6
312.0
330.6
268.2
204.7
280
330
240
6,000-100,000
350-600
150-400
*A1lowing for appropriate lag time between Conowingo & Bay Transects
-------
NITROGEN RELATIONSHIPS
CHESAPEAKE BAY BETWEEN TRANSECTS A & F
(45 x 109 ft3)
SUSQUEHANNA RIVER - CHESAPEAKE BAY
SUSQUEHANNA RIVER AT CONOWINGO
Date
04/22/68
05/22/68
06/24/68
07/09/68
08/12/68
09/04/68
12/04/68
03/06/69
05/22/69
06/18/69
07/09/69
09/03/69
12/17/69
02/18/70
03/30/70
05/20/70
06/11/70
07/07/70
08/10/70
10/06/70
11/11/70
04/19/71
05/17/71
06/16/71
07/13/71
08/17/71
10/13/71
TN
(mg/1)
1.22
.83
.83
.69
.60
.61
.70
.53
.85
.51
.53
.59
.72
1.17
1.21
.98
.60
.63
.65
.72
.82
.77
.94
.70
.50
.62
.62
Approximate Averages
Approx Av
Approx Av
(Jun-Oct):
(Nov-May):
TN
(103 Ibs)
3,425.8
2,330.6
2,330.6
1,937.5
1,684.8
1,712.9
1,965.6
1,488.2
2,386.8
1,432.1
1,488.2
1,656.7
2,021.8
3,285.4
3,397.7
2,751.8
1,684.8
1,769.0
1,825.2
2,021.8
2,302.6
2,162.2
2,639.5
1,965.6
1,404.0
1,741.0
1,741.0
:2,000
1,700
2,500
TIN
(mg/1 )
.23
.29
.18
.59
.94
.99
.62
.34
.15
.06
.37
.75
.70
.53
.12
.23
.06
.25
TIN
(103 Ibs)
645.8
814.3
505.4
1,656.7
1,656.7
2,780.0
1,741.0
954.7
421.2
168.5
1,039.0
2,106.0
1,965.6
1,488.2
337.0
645.8
168.5
702.0
1,000
600
1,900
Flow at
Conowi ngo*
(cfs)
100,000
50,000
100,000
70,000
40,000
40,000
20,000
20,000
50,000
40,000
33,000
19,000
6,000
100,000
40,000
88 ,000
40,000
40,000
20,000
20,000
10,000
80 ,000
60,000
50,000
60,000
35,000
15,000
45,000
40 ,000
50 ,000
Days
Required to
Fill Volume
(45 x 109 ft3)
5.2
10.4
5.2
7.6
13.0
13.0
26.0
26.0
10.4
13.0
15.8
27.4
86.8
5.2
13.0
5.9
13.0
13.0
26.0
26.0
52.1
6.5
8.7
10.4
8.7
14.9
34.7
Daily TN
Load at
Conowi ngo
(Ibs/day)
790 ,000
400 ,000
790 ,000
560,000
320,000
320,000
160,000
160,000
400,000
320,000
265,000
155,000
50,000
790,000
320,000
690 ,000
320,000
320,000
160,000
160,000
81 ,000
630,000
480 ,000
400,000
480 ,000
280 ,000
1 20 ,000
Expected
TN Load in
Volume
(103 Ibs)
4,108.0
4,160.0
4,108.0
4,256.0
4,160.0
4,160.0
4,160.0
4,160.0
4,160.0
4,160.0
4,187.0
4,247.0
4,340.0
4,108.0
4,160.0
4,071.0
4,160.0
4,160.0
4,160.0
4,160.0
4,220.0
4,095.0
4,176.0
4,160.0
4,176.0
4,172.0
4,164.0
4,000
4,000
4,000
Daily TIN
Load at
Conowi ngo
(Ibs/day)
235,000
195,000
110,000
34,000
600,000
235,000
520 ,000
235,000
235,000
116,000
116,000
57,000
480 ,000
360 ,000
295 ,000
360 ,000
205 ,000
87 ,000
Expected
TIN Load
in Volume
(103 Ibs)
3,055.0
3,081.0
3,014.0
2,951.0
3,120.0
3,055.0
3,068.0
3,055.0
3,055.0
3,016.0
3,016.0
2,970.0
3,120.0
3,132.0
3,068.0
3,132.0
3,054.0
3,019.0
3,000
3,000
3,000
Approximate Ranges: 1,400-3,400
200-2,700
6,000-100,000
*Allowing for appropriate lag time between Conowingo & Bay Transects
-------
TOTAL NITROGEN & PHOSPHORUS LOADINGS
CHESAPEAKE BAY BETWEEN TRANSECTS A and F (45 x I0*fl»)
28 - 37 MILES BELOW SUSQUEHANNA RIVER
ESTIMATED N LOAD FROM SUSQUEHANNA RIVER
ESTIMATED P LOAD FROM SUSQUEHANNA RIVER
OBSERVED LOADS
n
O
4000-
3600-
3200-
2800-
2400'
2000'
1600'
1200-
800-
400-
0
1968
1969
1870
1971
-------
SPATIAL PHOSPHORUS DISTRIBUTIONS
BALTIMORE HARBOR
MAIN CHANNEL STATIONS
(MES DATA)
.6 -i
.5 -
.4 -
.3 -
O
O-
.2 -
JULY-AUG. 1971
JULY-AUG. 1970
T
2
T
3
~r
4
T
5
~T
6
T
7
10
MILES FROM CHESAPEAKE BAY
-------
SPATIAL NITROGEN DISTRIBUTION
BALTIMORE HARBOR
MAIN CHANNEL STATIONS
(MES DATA)
LEGEND
2.5 -i
2.0 -
TOTAL NITROGEN (JULY - AUG.. 1971)
TOTAL NITROGEN (JULY-AUG., 1970)
INORGANIC NITROGEN (JULY - AUG..1971)
INORGANIC NITROGEN (JULY-AUG.. 1970)
1.5 -
S,
o>
1.0 -
.5 -
J_
_L
T
9
T
3
I
456
MILES FROM CHESAPEAKE BAY
T
7
~r
8
10
-------
SPATIAL CHLOROPHYLL DISTRIBUTION
BALTIMORE HARBOR
MAIN CHANNEL STATIONS
(MES DATA)
JULY-AUG. 1971
JULY-AUG. 1970
100 -i
80 -
60 -
o
tr
O
o
40 -
20 -
3
5
6
7
MILES FROM CHESAPEAKE BAY
8
!0
-------
COMPARISON OF TOTAL PHOSPHORUS CONCENTRATIONS
IN
TRANSECTS WITHIN CHESAPEAKE BAY
AND
TRANSECT ACROSS MOUTH OF BALTIMORE HARBOR
AVERAGE TPO4 IN BAY
AVERAGE TP04 AT MOUTH OF BALTIMORE HARBOR
en
E
.28
.24
.20 -
.16 -
.12 -
.08
.04
.1 1.1 .1 IJ>I
1968
1969
1970
1971
-------
COMPARISON OF INORGANIC NITROGEN CONCENTRATIONS
IN
TRANSECTS WITHIN CHESAPEAKE BAY
AND
TRANSECT ACROSS MOUTH OF BALTIMORE HARBOR
AVERAGE INORG. N IN BAY
1.20 -
1.10 -
1.00 -
.90 -
.80 -
.70 -
.60 -
.50 -
.40 -
.30 -
.20 -
.10 -
0
AVERAGE INORG. N AT MOUTH OF BALTIMORE HARBOR
-
J 1.1.1 IJ
T^Z < Z T
1 1 .1 .1 U
.1 .1
M j.i
i o o.
1969
.1 .1 .1 .1 IJVI .1^-1 .1 .1 .
1970
Ou
1971
-------
TIDAL DATA
FOR
HYDRAULIC VERIFICATION
Upper Chesapeake Bay
Actual Predicted Actual Phasing Predicted Phasing
Station Junction Range Range (H.W.) (L.W.) (H.W.) (L.W.)
(ft.) (minutes)
Susq. River at 7 1.7 2.0 +330 +372 +354 +408
Havre de Grace
Pooles Island
Baltimore
Fort McHenry
Sandy Point
Charleston
Northeast River
Tol Chester Beach
Love Point,
Chester River
Susq. River at
34
53
70
10
47
62
5
1.
1.
0.
1.
1.
1.
2.
2
1
8
9
2
1
1
1
1
0
2
1
1
2
.3
.2
.9
.1
.2
.1
.2
+179
+128
+43
+346
+144
+105
+ 368
+185
+146
+51
+374
+158
+106
+ 434
+186
+126
+54
+ 354
+ 168
+ 114
+ 366
+192
+114
+42
+ 396
+ 168
+ 102
+ 432
Port Deposit
-------
14 -
12 -
10 -
£- 8 -
<
i/)
6 -
4 -
2 -
0
LONGITUDINAL SALINITY PROFILES
UPPER CHESAPEAKE BAY
LEGEND
10/6/70 (OBSERVED)
8/10/70 (OBSERVED)
10/6/70 (PREDICTED)
0
12 16 20 24 28
MILES BELOW SUSQUEHANNA RIVER
32
36 40
-------
14 i
LONGITUDINAL SALINITY PROFILES
UPPER CHESAPEAKE BAY
12-
10-
LEGEND
5/17/71 (OBSERVED)
4/19/71 (OBSERVED)
5/17/71 (PREDICTED)
Q
>-
K
Z
6-
4 -
2-
12 16 20 24 28
MILES BELOW SUSQUEHANNA RIVER
32
40
-------
LONGITUDINAL PHOSPHORUS PROFILES
UPPER CHESAPEAKE BAY
(SUSQ. FLOW = 10,000 cfs)
8/10/70 (OBSERVED)
10/6/70 (OBSERVED)
10/6/70 (PREDICTED)
DECAY RATE=0.008/day
a>
e
o
a
.3-
.2-
4
8
I
12
16
20
24
28
32
MILES BELOW SUSQUEHANNA RIVER
I
36
I
40
-------
LONGITUDINAL PHOSPHORUS PROFILES
UPPER CHESAPEAKE BAY
(SUSQ. FLOW = 50,000 cfs)
0.6-1
0.5-
4/19/71 (OBSERVED)
5/17/71 (OBSERVED)
5/17/71 (PREDICTED)
DECAY RATE = 0.01 5/day
0.4 -
a>
e
o
a.
0.3 -
0.2-
0.1 -
oo
I
8
I
12
I
16
I
20
24
28
32
I
36
40
MILES BELOW SUSQUEHANNA RIVER
-------
0.0
LONGITUDINAL INORGANIC NITROGEN PROFILES
UPPER CHESAPEAKE BAY
(SUSQUEHANNA FLOW = 23,000 cfs)
LEGEND
5/20/70 (OBSERVED)
7/7/70 (OBSERVED)
7/7/70 (PREDICTED)
DECAY RATE = 0.055/day
0
12 16 20 24 28
MILES BELOW SUSQUEHANNA RIVER
32
40
-------
LONGITUDINAL INORGANIC NITROGEN PROFILES
UPPER CHESAPEAKE BAY
(SUSQUEHANNA FLOW = 50,000 cfs)
1.2 -i
LEGEND
4/19/71 (OBSERVED)
1.0 -
X
,§ 0.8 -
5
o
0.6 -
o
z
g 0.4-1
O
0.2 -
4/17/71 (OBSERVED)
-. 5/17/71 (PREDICTED)
DECAY RATE = O.OIO/day
~t
4O
0.0
T
T
T
8
~r
12 16 20 24 28
MILES BELOW SUSQUEHANNA RIVER
32
36
-------
EFFECT OF CHLOROPHYLL
ON
DECAY RATE OF INORGANIC NITROGEN
UPPER CHESAPEAKE BAY
(BASED ON MATHEMATICAL MODEL SIMULATIONS)
CHLOROPHYLL o_ (/ug/D
-------
LONGITUDINAL CHLOROPHYLL PROFILES
UPPER CHESAPEAKE BAY
(SUSQ. FLOW = 23,000 cfs)
LEGEND
5/20/70 (OBSERVED)
7/7/70 (OBSERVED)
7/7/70 (PREDICTED)
80 i
60-
40-
20-
~T
12
T
~T
16
20 24 28
MILES BELOW SUSQUEHANNA RIVER
~T
32
36
40
------- |