-------
-------
EPA-903/9-80-002
ASSESSMENT OF 1978
WATER QUALITY CONDITIONS
IN THE UPPER POTOMAC ESTUARY
March 1980
Leo J. Clark
Stephen E. Roesch
and
Molly M. Bray
U.S. Environmental Protection Agency
Region III
Central Regional Laboratory
839 Bestgate Road
Annapolis, Maryland 21401
-------
DISCLAIMER
This report has been reviewed by the U.S. Environmental Protection Agency
and approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
-------
This report is dedicated to the
memory of Charlotte Gannett,
founder and president of the
Montgomery Environmental Coalition,
whose untiring dedication to the
environmental movement in general
and the Potomac in particular
will long be remembered by the
rest of us who strive towards a
better understanding of this
complex estuary.
m
-------
TABLE OF CONTENTS
Chapter Page
List of Figures vi
List of Tables ix
Acknowledgements x
I. Introduction and Description of Study . 1
II. Findings and Conclusions 8
A. Physical 8
B. Nutrients 15
C. Algae 34
D. DO - BOD 41
E. Point Source Assessment 55
F. Chain Bridge Inputs 58
G. Urban Inputs 62
References 67
Appendix 68
-------
LIST OF FIGURES
Number Page
1 Comparison of 1977 and 1978 Hydrographs 9
for the Potomac River at Little Falls
(July - September)
2 Water Temperature, Rainfall and Flow 10 .
Characteristics for the 1977 Potomac
Monitoring Period
3 Water Temperature, Rainfall and Flow 11
Characteristics for the 1978 Potomac
Monitoring Period
4 Comparison of Selected 1977 and 1978 13
Secchi Disk Data (Potomac Estuary
between Piscataway and Possum Point)
5 Secchi Disk vs Chlorophyll a, Freshwater 14
Portion of Potomac Estuary T19J7 and
1978 Data)
6 Potomac Estuary Water Quality Data - 16
Turbidity (August 1978)
7 Potomac Estuary Water Quality Data - 18
Phosphorus Fractions (July 17-19, 1978)
8 Potomac Estuary Water Quality Data - 19
Phosphorus Fractions (August 1-3, 1978)
9 Potomac Estuary Water Quality Data - 20
Phosphorus Fractions (August 14-16, 1978)
10 Potomac Estuary Water Quality Data - 21
Phosphorus Fractions (September 11, 1978)
11 Potomac Estuary Water Quality Data - 22
Phosphorus Fractions (September 25-27, 1978)
12 Potomac Estuary Water Quality Data - 23
Nitrogen Fractions (July 17-19, 1978)
13 Potomac Estuary Water Quality Data - 24
Nitrogen Fractions (August 1-3, 1978)
-------
LIST OF FIGURES (Continued)
Number Page
14 Potomac Estuary Water Quality Data - 25
Nitrogen Fractions (August 14-16, 1978)
15 Potomac Estuary Water Quality Data - 26
Nitrogen Fractions (September 11, 1978)
16 Potomac Estuary Water Quality Data - 27
Nitrogen Fractions (September 25-27, 1978)
17 Potomac Estuary. Water Quality Data - 32
N to P Ratios (1978)
18 Potomac Estuary Water Quality Data - 33
N to P Ratios (1977)
19 Carbon-Chlorophyll Relationship, Potomac 37
Estuary (1977 - 1978 Data)
20 Nitrogen-Chlorophyll Relationship, Potomac 38
Estuary (1977 - 1978 Data)
21 Phosphorus-Chlorophyll Relationship, Potomac 39
Estuary (1977 - 1978 Data)
22 Relationship of Surface and 5 Foot DO 42
Measurements, Stations 4, 5, 5A, 6 and 7 -
Potomac (July 17 - September 27, 1978)
23 Relationship of Surface and 5 Foot DO 43
Measurements, Stations 8, 8A, 9, 10 and 10B -
Potomac (July 17 - September 13, 1978)
24 Relationship of Surface and 5 Foot DO 44
Measurements, Stations 8, 8A, 9, 10 and 10B -
Potomac (July 17 - August 3 and September
5, 1978) Chlorophyll a, a? 20-60 yg/1
25 Relationship of Surface and 5 Foot DO 45
Measurements, Stations 8, 8A, 9, 10 and 10B -
Potomac (August 28 - September 13, 1978 -
Excluding September 5), Chlorophyll a_
^ 60-100 yg/1
26 Drogue Study DO Data, Upper Potomac Estuary 47
(Rosier Bluff - Piscataway), July 31 and
August 29, 1978
vii
-------
LIST OF FIGURES (Continued)
Number Page
27 Drogue Study DO Data, Potomac Estuary 48
(Rosier Bluff - Piscataway), September
13, 1978
28 Summary of Diurnal DO Data, Potomac 49
Estuary (Woodrow Wilson Bridge to Indian
Head), Surface Data
29 Summary of Diurnal DO Data, Potomac 50
Estuary (Woodrow Wilson Bridge to Indian
Head), Bottom Data
30 Potomac Estuary Water Quality Data - 1977 53
and 1978 Sediment Oxygen Demand Measurements
(Corrected to 20°C)
vm
-------
LIST OF TABLES
Number page
1 1978 Potomac Estuary Sampling Stations 3
2 Potomac Slack Water Runs 4
3 Parameter List 5
4 Relationship Between Blue Plains' Nutrient 30
Inputs and Maximum Concentration Response in
Potomac Estuary
5 S.T.P. Effluent Data Summary 56
Pollutant Concentrations
6 S.T.P. Effluent Data Summary 57
Pollutant Loadings (Average)
7 Wastewater Loading Trend 59
Upper Potomac Estuary
8 1978 Chain Bridge Data 60
Pollutant Concentrations
9 1977 Chain Bridge Data 61
Pollutant Concentrations
10 Pollutant Loading Trend 63
Potomac River at Chain Bridge
11 Estimated Urban Loading During 1978 64
Study Period
12 Delineation of Major Pollutant Loads, 66
Upper Potomac Estuary (1978 Study Period)
IX
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ACKNOWLEDGEMENTS
The considerable effort provided by Dr. James Allison, Maryland
Water Resources Administration in identifying and counting the algae
collected from the Potomac Estuary was an essential component of this
study and is gratefully acknowledged. The special assistance provided
by Dr. Philip Sze, Georgetown University, in this regard is also
appreciated.
The operators and support staff at the following wastewater
treatment plants are acknowledged for their cooperation and assistance
during the course of this study:
Blue Plains, District of Columbia
City of Alexandria
City of Arlington
Piscataway, Washington Suburban Sanitary Commission
Westgate, Fairfax County
Hunting Creek, Fairfax County
Dogue Creek, Fairfax County
Pohick Creek, Fairfax County
The authors also wish to acknowledge the assistance of the Annapolis
Field Office Staff Members, in particular the draftsmen, Joel Singerman,
Gerard Donovan, and Gerard Crutchley, and the typist, Ann Donaldson.
-------
CHAPTER I
INTRODUCTION AND DESCRIPTION OF STUDY
The challenge to improve the Potomac Estuary through reduction of
point source pollutant loadings necessitates the periodic collection of
field data to assess trends and the nature and scope of existing water
quality stresses. AFO's ongoing efforts to improve and refine its pre-
dictive mathematical models imposes still another need for the acqui-
sition of extensive water quality information. It is within these
contexts that AFO embarked on its second successive intensive monitoring
program in the Potomac in 1978. It seems axiomatic that there is never
sufficient water quality data to answer all of the complex questions
confronting us since natural systems are unpredictable. There is
nevertheless a vital need for the decision makers to be kept informed
of scientific data and technical findings to ensure a rational and
defensible course of action. The intent of this report is to present
findings and conclusions along with tabulations and graphs of the data
from our 1978 studies. In many instances these findings and conclusions
will be contrasted with those documented during 1977 [1]. The fact that
significant data bases were obtained during two successive summers having
different characteristics such as river flow allows for many comparisons
to be made and better insight of water quality behavior.
The actual monitoring program covered the period from July 17 to
September 27, 1978. In most respects it closely paralleled the study
performed in 1977, and in others it served as an extension to further
1
-------
the knowledge in particular areas or to eliminate data gaps. The three
principal elements of this program are described below.
1. Ambient Water Quality Monitoring
A total of 13 slack water boat runs were made from the Route
301 Bridge to Chain Bridge. These were normally scheduled twice per
week on alternate weeks. The stations sampled during each run were
identical to those of the 1977 survey and are presented in Table 1.
Table 2 shows the dates, times and other relevant information pertaining
to each of the individual slack water runs.
The parameters that were analyzed during the 1978 ambient
monitoring program were largely the same as 1977, with the most notable
exception being that DO was run at two depths (surface and 5 feet)
instead of one. Other differences included more filtered nutrient
analyses in 1978, but no herbicides data. All of the monitored parameters
are contained in Table 3.
2. STP Effluent Monitoring
This effort too was identical to what was performed during the
1977 survey in that 24 hour composite effluent samples were collected
from the eight major wastewater treatment facilities on the same day as
the slack water runs. Analyses were completed for the same nutrient
fractions shown in Table 3 along with turbidity, BOD5 and ultimate BOD.
The latter two parameters were run on an alternate basis because of
laboratory constraints. In addition, wastewater flow measurements were
taken in order to compute loadings.
3. Special Studies
Those studies of a special nature that were an integral part
2
-------
TABLE 1
1978 POTOMAC ESTUARY SAMPLING STATIONS
Station
Number
P-8
P-4
1
1-A
2
3
4
5
5-A
6
7
8
8-A
9
10
10-B
11
12
13
14
15
15-A
16
NAME
Chain Bridge
Above Windy Run (opposite Georgetown Reservoir)
Key Bridge
Memorial Bridge
14th Street Bridge
Ha ins Point
Bellevue
Woodrow Wilson Bridge
Rosier Bluff
Opposite Broad Creek
Fort Washington (Piscataway)
Dogue Creek - Marshall Hall
Opposite Gunston Cove
Chapman Point - Hallowing Point
Indian Head
Deep Point - Freestone Point
Possum Point
Sandy Point
Smith Point
Maryland Point
Opposite Nanjemoy Creek
Mathias Point
Route 301 Bridge
RMI*
0
1.90
3.35
4.85
5.90
7.60
10.00
12.10
13.60
15.20
18.35
22.30
24.30
26.90
30.60
34.00
38.00
42.50
45.80
52.40
58.55
62.80
67.40
*Miles below Chain Bridge
-------
TABLE 2
Potomac Slack Water Runs
July - September, 1978
Date
7/17
7/19
8/01
8/03
8/14
8/16
8/28
8/30
9/05
9/11
9/13
9/25
9/27
Tide
LWS
LWS
LWS
LWS*
HWS*
LWS
HWS*
LWS
HWS
HWS
LWS
HWS
_
Start
Time
0900
1050
1200
1040
1140
0940
1230
1120
0900
1045
0800
1045
0850
End
Time
1340
1545
1500
1520
1615
1450
1650
1400
1100
1525
. 1240
1500
1520
River
Flow
(cfs)
6050
6090
9330
7190
16500
14500
3250
4040
5530
2660
2760
2290
2190
*Slightly ahead of slack
-------
TABLE 3
Parameter List
1978 Potomac Study
Nitrogen Series
TKN (filtered and unfiltered)
NO| + N03
Phosphorus Series
Total P04 (filtered and unfiltered)
Inorganic P04
Carbon Series
Total Organic C (filtered and unfiltered)
Biological
Chlorophyll a^
Phytoplankton Counts & Identification*
Physical
Temperature
Turbidity
Seechi Disc
Salinity
Conductivity
PH
Oxygen Series
BOD5*
BOD ultimate*
DO (surface and 5 feet)
*Performed on a selective basis
-------
of the Potomac monitoring program are briefly described below. They
were designed and conducted to define or refine particular inputs to a
mathematical model or to acquire specific knowledge concerning the dis-
solved oxygen budget and algal effects.
a. Drogue Studies
On a monthly basis a floating drogue was used to identify
a parcel of water within a critical segment of the Potomac Estuary
(Rosier Bluff - Piscataway) over a diurnal sampling period. Hourly
samples were collected while following the drogue and analyzed for DO
and chlorophyll.
b. Algal Species Identification and Cell Counts
As mentioned previously (Table 3) selected algal samples
were collected during the study and visually analyzed under a microscope
for identification and quantification purposes.
c. Long Term BOD Delineation Study
The purpose of this laboratory study was to obtain a further
breakdown of the BOD components to include not only the carbonaceous and
nitrogenous fractions but the algal fraction as well. An in-depth know-
ledge of BOD behavior will facilitate a better analysis of both effluent
and river data, including cause and effect relationships, as well as a
more precise representation of this parameter in the model. A separate
report has already been published by Slayton and Trovato [2] which
documents the results of this study and the procedures followed.
d. Algal Elemental Composition Analysis
Concentrated samples of algal cells collected from the
Potomac Estuary were analyzed in the laboratory to obtain further
6
-------
information concerning the relative quantities and atomic ratios of
total (i.e. both protoplasmic and stored) carbon, nitrogen and phosphorus
associated with a given bloom condition.
e. SOD Study
Numerous measurements of the oxygen demand attributable to
bottom sediments were made using a specially designed benthic respirometer.
In addition, a general bottom mapping survey was conducted throughout the
upper estuary to assist in the interpretation of the individual SOD results.
Two other special studies (i.e. Light/Dark Bottle DO Measure-
ments and Low Flow DO Profiling below Chain Bridge) were contemplated
during the course of this program but were not completed because of un-
satisfactory ambient conditions.
-------
CHAPTER II
FINDINGS AND CONCLUSIONS
A. Physical
1. The most significant difference between the 1977 and 1978 study
periods was the magnitude of the freshwater flows to the Potomac Estuary.
These hydrographs are depicted in Figure 1. The 1977 study occurred
under low flows (% 1500 cfs - average) whereas the summer of 1978 was
characterized by higher and more erratic flows, which were a major
driving force in terms of water quality behavior. River flows during
the 1978 study period ranged from 35,000 cfs to 2,200 cfs with an
average of 6,900 cfs.
2. An analysis was made of the 1977 and 1978 rainfall data which
was collected by the U.S. Weather Service at Washington National Airport
and shown in Figures 2 and 3. During the 1977 study period about 6.4
inches of rainfall occurred as compared to about 7.4 inches for 1978.
An examination of the 1977 and 1978 hydrographs for the Potomac River
indicated that the nature of the storm events must have been quite dif-
ferent since the rainfall quantities were fairly similar. It appears
that the 1977 storms were generally of the localized (thunderstorm)
variety, which did not substantially affect the base flow in the river.
These could produce a significant non-point source loading to the estuary
from the Washington Metropolitan Area without the benefit of added dilution
and flushing. The 1978 storms, on the other hand, were probably more
8
-------
100.000-1
COMPARISON OF 1977 & 1978 HYDROGRAPHS
POTOMAC RIVER AT LITTLE FALLS
(JULY - SEPTEMBER)
1,000
15 20
AUGUST
T
10 15 20
SEPTEMBER
25
FIGURE-I
-------
WATER TEMPERATURE, RAINFALL, & FLOW CHARACTERISTICS
FOR THE 1977 POTOMAC MONITORING PERIOD
o
a
UJ
a
2
31-
30-
29-
28
27
26
25
1.5
< 1.0-
u.
z
* 0.5H
0
4000-
3000-
1000-
INDICATE ACTUAL DAYS OF SAMPLING
JULY
AUG.
SEPT.
FIGURE-2
10
-------
<
ir
a
2
UJ
WATER TEMPERATURE, RAINFALL. & FLOW CHARACTERISTICS
FOR THE 1978 POTOMAC MONITORING PERIOD
29-
2.0-
e
1.5-
! '-"i
ce
0.5-
INDICATE ACTUAL DAYS OF SAMPLING
30.000-
15
11
-------
widespread as shown by the hydrograph responses and may have a lesser
impact on water quality.
3. The average water temperature during the 1978 study period was
26.5°C, approximately 1° less than the average 1977 water temperature
(see Figures 2 and 3). The daily minimum and maximum measured water
temperatures were 22.9°C and 28.5°C (September 27 and August 28
respectively). Spatial variations in temperature over a given sampling
run were normally less than 2°C with no consistent pattern evident.
4. There appeared to be a very strong relationship (inverse)
between flow and Secchi Disk in the critical algae producing reach of
the upper estuary during mid-August, 1978 when peak flows (10,000 -
35,000 cfs) occurred, but not during the remainder of the study period.
Minimum Secchi Disk depths at that time ranged between 10" and 14".
5. A comparison of the Secchi Disk data collected during the July
periods in 1977 and 1978, when chlorophyll levels were relatively low
and minimal interference would be expected, indicated that comparable
conditions with respect to light transmission occurred in the critical
algal production reach of the estuary. Secchi Disk readings for both
years averaged about 22 inches (except when high flows prevailed) as
can be seen in Figure 4.
6. Examining all of the Secchi Disk data for 1977 and 1978 as a
function of chlorophyll, which is presented in Figure 5, does not suggest
a significantly different light regime between the two years. Unfortu-
nately, no chlorophyll data was available during the peak flow sampling
runs when pronounced differences would be expected. Although 1978 flows
were generally much higher than 1977, there was only about a 2" difference
12
-------
COMPARISON OF SELECTED 1977 & 1978 SECCHI DISK DATA
POTOMAC ESTUARY BETWEEN PISCATAWAY & POSSUM Pt.
-5
c
32-
28-
24-
20-
12-
8-
4-
CHLOROPHYLL < I40/j,g/l
AVG/
\
V)
5
32-
§
hJ 28
24-
20-
oo
2 "
12-
8-
4-
RANGE
CHLOROPHYLL » UOfJ.m/1 DURING THIS PERIOD
20 25 30 '
JULY
10 15 20 25
AUGUST
30 ' 5 10 15 20
SEPTEMBER
FIGURE-4
13
-------
SECCHI DISK vs CHLOKUPHYLL a
FRESHWATER PORTION OF POTOMAC ESTUARY
(1977 AND 1978 DATA)
1977
x 1978
30'
28
26
24
2 22
i
* 201
_ 181
I
O
u>
14
12
10
8
XX X
I 9 78
4
2
20 40 60 80 100 120 140 160 180 200 220 240 260
CHLOROPHYLL a - uq/l
FIGURE-5
14
-------
in Seccht depth for the lower half of the chlorophyll spectrum.
7. The turbidity levels in the Upper Potomac were also strongly
influenced by river flow as shown in Figure 6. During relatively low
flows (4,000 cfs) the turbidity was very constant ranging between 5 and
8 NTU. However, the high flow condition (15,000 cfs) exhibited turbidity
values ranging from 28 NTU at Chain Bridge to 7 NTU at Smith Point. It
is interesting to note that there was a steady decline in turbidity
throughout this 45 mile reach presumably because of sedimentation and
dilution.
B. Nutrients
To facilitate the evaluation and interpretation of the nutrient data
as well as other selected data obtained from this study, the entire study
period was divided into much shorter sub-periods which were as comparable
as possible with respect to (1) river flow, (2) water temperature, (3)
occurrence of storm events and (4) algal bloom proportions. The grouping
of data of similar origin strengthens the conclusions concerning spatial
and temporal trends, the effects of one parameter on another, and the
basic transport, transformation and fate of different pollutants. Those
periods selected for purposes of this report are as follows:
Time
July 17-19
August 1-3
August 14-16
September 11
Flow Temperature Comments
6,000 cfs 25.5°C Dry - little algae
8,000 cfs
15,500 cfs
27.5°C
28°C
2,700 cfs
September 25-27 2,300 cfs
26°C
23°C
Between storm events
Follows major storms
Dry - algae increasing
Dry - maximum bloom period
15
-------
91
CONCENTRATION N T U
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Spatial profiles for five different measured forms of phosphorus
are depicted in Figures 7-11 for each of the above time periods.
Liekwise, five nitrogen fractions are included in Figures 12 - 16.
The following observations can be made relative to these data:
1. Distributions of soluble Pi (as P04), soluble TP04 and TP04 are
quite similar during each of the five sub-periods investigated. Except for
the high flow period (August 14-16), when the Chain Bridge input appeared
to dominate the phosphorus trend in the upper portion of the estuary,
these phosphorus fractions also exhibited similar distributions from
one time period to the next.
2. Filtered inorganic (reactive) phosphorus generally increased
from about 0.05 mg/1 to 0.15 - 0.20 mg/1 in the vicinity of Blue Plains.
The maximum concentration in this area, 0.35 mg/1, occurred in late
September when river flows were low. Farther downstream, concentrations
declined to the 0.05 to 0.10 mg/1 range, which approximates the classical
limiting value of phosphorus for algal growth (i.e. 0.03 mg/1 as P).
3. There is a consistent and dramatic increase in filtered Pi levels
below river mile 30 (Indian Head) which are not attributable to external
sources. Releases from the bottom sediment which could be strongly
influenced by salinity, DO, iron, pH and other factors is a suspected
(currently being investigated by USGS) cause of these elevated Pi levels
which often exceed 0.3 mg/1. Considering the fact that the estuary's
volume increases substantially in this lower reach, the changes in
actual mass would be more appreciable than the concentration profiles
indicate.
4. As mentioned previously, the total phosphorus (both filtered
17
-------
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\ .POHICK CH. O
\ 2
^^k
\ >
\ i °
\ / H m
\ i 2 w
\ I m H
\ ! -D E
i 1 rn ^
!/ 5 5
!/ ^ 5
/f § -*
V « 5
\ 35: 33
\ OB
\ So
-= S
1 >
i o
\ \ i 5
\ \ 3 >
/ "
/ S
/
/ i 1
: -o -D "O
Sis
2* 31
0 £ ~
^^
~~~**~* ^
(
»
-------
S.T.P.'-
POTOMAC ESTUARY WATER QUALITY DATA
FLOW- 2300 ef*
TEMP. : 23*C
TIDE : HWS
at
U
ui
O
O
P.
TIME PERIOD:
SEPTEMBER 25-27.1978
PARAMETERS:
AS P04
ro
O.S
0.4
0.3
^ 0.2.
in
* 0..
z
o
\-
<
cr
5 °-6
u
z 0.5-
O
U 0.4-
0.3-
0.2
O.H
A.RO.
STA.
NO-
TPO4
TP04 (fill.)
4
0.
~ OQCVI O ^
(M
iO
-------
ei-aanou
z
p
o
in-
o
in
IV>
O
IV)
Cn
aj
mo
VI
00 Co
r
O
31
_
Z
73
O
O
Sg-
tn .
Cn
O> .
0
o> .
in
-si .
o
in 3
> C
P4-
1-
2B-
z-
3-
4-
S
C A
oA-
e
7-
8-
8A-
9-
10
108
If-
12
13
14
15-
ISA
16
v*xsi^wL_i^tr\ri*iv
1 O O - _ IV) W
> ^ cp K> q> b f
;
\
\
\
x»».^ \
*^^
.
*
1
1
1
I
1
I
i
1
1
1
1
1
1
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/
/
j
;
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i
t
i
i
i
~i
_j
>
z
/ l^i \ my / i /
p p p p _ - ^
iv) ^ op b K) '^
l ./" /
/ /
\ / -» H
\ \ og
1 ) "^
\
1 \ .ARLINGTON fIVi
^> 1 \ ,BLUE PLAIhfS^ O>
l**'"-^... \ .ALEXANDRIA. XV
i 1 " ^^ _ *
\ 1 i *~» WESTGATE
1 1 ^
\ 1 *s"
/ X
/I / \
I / \ ^PISCATAWAY
\ 1 ! -HUNTING CH.'
i y , .pvmmM %.n.
\ / 1 DOGUE CR.
\ / I
\ / l .POHICK CR.
/ '
/ /
/ / /
K '
/ / _.
x i
/ \ 3..
/ \ n
1 \
\ ' -o
V ' m
) ! 5
/ °
/ i I
1 c
/ r"
f / *
\ / $
/ 5
s
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1 "
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' ill
ill
i | i
ill
1 ' z z tn -o
I 8 ? P |
i So
o i; a>
to P p
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3D
D
C
^
n
H
<
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-------
ro
-F*
o
c
TO
POTOMAC ESTUARY WATER QUALITY DATA
FLOW : 8000 eft
TEMP. : 27.5'C
TIDE : LWS
a <
TIME PERIOD: AUGUST 1-3,1978
PARAMETERS
SIP
PART. ORG. N
SOL. ORG. N
NH3
NOz t N03
\.
UJ
2.0-
TOTAL N
> 1.6-
1.2-
0.8-
0.4.
A.F.O
STA.
C
1
~^"X ''"' X\x
Q.CVJ >o co o ~~ ~ in
) 5 10 15 20 25 30 35 40 45 50 55 60 65 70
MILES BELOW CHAIN BRIDGE
-------
z
o
o<-
0'
~-
ro.
o
ro
W
s.
r~ (*>
mo'
w
CD
. "
r~ ^^
i
_ A.
i°
z
30
M
O
0
mg
Cn
o»
O
Cn
O
3, CONCENTRATION (mg/l)
-H-ripo r°r° p o p p _ ijj
^O-^K)0)O4^ KJ & o> 09 o K) ."n
P4-
1-
28-
2-
3-
4-
5
5 A-
6-
7-
8-
8A-
9.
10
IOB
II
12-
13-
14-
15-
I5A-
16.
/
(
I
\
V
f
i
1
1
1
r
i (
i
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;
I
/
i
i
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/
/
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y
/ 1
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I '
I
Z
I
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j
*
J
/
/ /
1
I -.H ^
I m i
/ ° 2 0
/ ^ ."^ 5
r " "
/ X ro r;
1 ,ARLINGTOM < O) !
/ JLUEPLAIN_S$ ^ g
/ pa O
r , I
^N 1 WESTGATE ^ *
\i O)
i
\ |
1
1 ,PISCATAWAY
1
/ .HUNTING CB.
' ' T>
/ ^DOGUE CR, O
\s' -POH1CK CR. O
M ?
1 5>
» 0
1
H m
2 3
: f
i m >^
30 JQ
o <
o
s 1
0 H
f- ^^\
S D
i
en ^~
>
3 C
OB _|
/ -o -<
/ > ?
/ S _j
5 >
/ rn
y f A
.
V 1 / i ' 1
M ! I
/ / ! 1
/ / z z w 5
J / / 0 I 0 >
1 ' ' ~ ~ H
I 11
2 _
2
-------
CONCENTRATION (mg/l)
_ IN) IN) Oppp__
rv> O) O A K> '*. 01 op p K)
IV)
o
fv>
to
»<
ni(
O
I<
z
»'
o
S 5 R
* O
-------
ro
O
c
3)
2300 cfs
23'C
POTOMAC ESTUARY WATER QUALITY DATA
TIME PERIOD: SEPTEMBER 25-27, 1978
PARAMETERS:
PART. ORG. N
SOL. ORG. N
-- NH3
NO2+ NO3
TOTAL N
1.2-
0.8-
0.4-
A.FO.
STA.
\ / "*x ._
* -^
^ CQ(\4«\5*lO
-------
and unfiltered) distributions were similar to Pi in that peak concen-
trations occurred near Blue Plains (% 0.5 mg/1 - TP04 and % 0.2 mg/1 -
TP04 filtered) and in the lower 15 miles of the study area. Since
filtered organic P remains relatively low and constant throughout, it
is reasonable to assume that these down river TP04 peaks largely reflect
the erratic behavior of Pi, generally the predominant form of phosphorus.
5. In the vicinity of Blue Plains approximately 1/2 of the total
phosphorus is in the particulate form possibly because of a significant
adsorptive reaction. This ratio increases somewhat in the algae pro-
ducing reach because of biological uptake of soluble P and decreases in
the lower 15 miles where the salinity influence is greatest.
6. During the four lower flow sub-periods there appeared to be a
significant amount of nitrification occurring as evidenced by the NH3
and N02 + N03 profiles. The NH3 fraction generally peaked in the vicinity
of Blue Plains at about 1.1 - 1.5 mg/1 and then declined fairly rapidly
to background levels. This decline was accompanied by dramatic increases
in N02 + N03 also in excess of 1.0 mg/1. Distribution of these two forms
of nitrogen were much different, however, during the high flow sub-period.
The effects of dilution in the case of NH3 and the dominance of the N02 +
N03 entering the Potomac as a result of the high flows are vividly demon-
strated by the August 14-16 profiles (Figure 14). As can be seen they
greatly masked the nitrification process.
7. The organic nitrogen in the particulate form is relatively low
throughout the Potomac with the bulk of the concentration values being
less than 0.3 mg/1. Peak concentrations were observed in the vicinity
of Blue Plains and in the algae producing area between Gunston Cove and
28
-------
Possum Point. These low values probably reflect the lack of a major
algae bloom. It is interesting to note that particulate organic nitrogen
was extremely low (i.e. <0.2 mg/1) even during the high flow sub-period
when suspended sediment loads should be at a maximum.
8. Soluble organic nitrogen was somewhat higher but no more erratic
than the particulate form. Concentrations were consistently less than
0.5 mg/1 regardless of time or location. The two highest values, 0.8
and 0.5 mg/1 did, however, occur in the vicinity of Piscataway Creek for
unexplained reasons.
9. When eliminating the unusual distribution associated with the
high flow sub-period, it can readily be seen that total nitrogen is
diluted (in contrast to phosphorus) in the lower 45 - 50 miles of the
study area. Concentrations diminish in this reach from over 2.0 mg/1
to about 0.4 mg/1.
10. Historical water quality data indicates that there is a distinct
relationship between the concentration of a pollutant in Blue Plains
effluent and the maximum concentration of that pollutant in the main
channel of the Potomac Estuary. Moreover, the estuary's response to a
load input is also somewhat affected by inflow rates. This data is
presented in Table 4.
Total N concentrations from Blue Plains average about 15 mg/1.
Maximum river concentrations ranged from about 4.0 mg/1 at low flow
conditions (1,000 cfs) to about 2.0 mg/1 at high flow conditions (10,000
cfs). A similar situation occurs with NH3 except its non-conservativeness
produces concentrations which are about 1/2 those for total nitrogen.
The dramatic reduction in the Blue Plains phosphorus concentrations
29
-------
TABLE 4
Relationship Between Blue Plains' Nutrient Inputs
and Maximum Concentration Response in Potomac Estuary
Blue Plains Effluent
Max. Cone. - Potomac
GO
o
Time Period
August 12-14,
1969
July 22, 1970
July 17-
August 3, 1978
August 14-16,
1978
August 19-22,
1968
July 1, 1969
July-August,
1977
September 11-27,
1978
Flow
(cfs)
8,000
4,800
7,000
15,000
2,500
1,000
1,500
2,500
Temp
°C
26
26
27
28
28
28.5
27
24.5
Flow
mgd
273
271
326
360
260
263
276
300
TN
15
14
15
15
15
15
15
15
NH3 T
iTiR/1
10
10
13
13
10
10
13
13
P04 Pi
15 10
20 12
4 2
4 2
20
15 10
5 3
4 2
TN
3.0-
3.5
3.0
2.0-
2.5
1.5
3.0-
3.5
4.0-
4.5
2.5-
3.0
2.5-
3.0
NH3
mg/1
1.0-
1.5
1.0
1.0-
1.3
0.6
1.5-
2.0
2.0
0.5-
1.0
1.5
TP04
1.5-
2.0
1.5
0.5
0.45
2.0
3.0
0.6
0.5
Pi
>.
1.0-
1.5
1.0
0.15'
0.2
0.2
El. 5
2.5
0.2-
0.3
0.2-
0.3
-------
over the past 10 years is also vividly depicted in the estuary data.
When TPO* effluent concentrations of 15 - 20 mg/1 were experienced,
maximum estuary responses of 1.5 - 3.0 mg/1 were recorded. More
current data, on the other hand, shows that an effluent concentration
of about 4 mg/1 produces a maximum response in the estuary of about
0.5 mg/1. In both instances there appears to be a dilution ratio of
about 10 to 1.
11. As can be seen in Figure 17, similar trends occurred with
respect to the ratio (ambient not cellular) of inorganic N to P (by
atoms) except for the high flow period of August 14-16. Minimum values
in the range of 40 - 80:1 occurred immediately downstream of Blue Plains.
These ratios then increased to 115 - 135:1 at the start of the algae
producing reach (RM 20 - 30) and finally underwent a very dramatic
decrease in the remaining 35 miles of the study area. In every instance
the N:P ratios were 7:1 or less at the stations fartherest downstream.
During the high flow period, upper basin inputs dominated the pattern
of N:P ratios which were relatively constant and always less than 68:1.
Comparing the 1977 and 1978 ambient N:P ratio data (Figure 17 and
18) reveals that their rate of spatial decline, or the tendency for
nitrogen to rate limit algal biomass production, appears to be a function
of the bloom size as measured by chlorophyll a_.
12. It is not certain which, if any, nutrient is rate limiting algae
growth during the summer of 1978. The available water data (ambient)
is somewhat inconclusive on this point. There are locations within the
critical zone where soluble inorganic P04 dips below 0.1 mg/1 (0.03 mg/1
as P), a level traditionally considered as potentially rate-limiting in
31
-------
POTOMAC ESTUARY WATER QUALITY DATA
S.T.R:
TIME PERIOD:
JULY 17. 1978
AUGUST 1-3.1978
-AUGUST 14-16. 1978
-SEPTEMBER 25-27.1978
PARAMETERS
N to P RATIO
CA>
ro
125-
§100
3 75
< 50
OC
a
o
2 25-
? A.F.O
g STA.
31
m
NO.
£ ~ S * *> *' "> J »
^^ 1^
^^ vQ
-------
POTOMAC ESTUARY WATER QUALITY DATA
STP
«D « K
So * °
§1 11
2 3 O O
ax o a
t * * t
TIME PERIOD
JULY IS - AUG 8, 1977
PARAMETERS
N to P RATIO
AUG 22 -SEPT 6.1977
175-
CO
10
IS
20
25 30
MILES
35 40 45 SO
BELOW CHAIN BRIDGE
55
60
70
-------
certain environments. However, these low levels are very temporary
since consistent increases are observed in other downstream portions
of the critical zone that appear to be independent of algal growth
conditions. In fact, this phenomenon, whose causes are still specula-
tive, was also observed during the 1977 study period. Ratios of
inorganic or available N:P would generally tend to indicate a surplus
of nitrogen but one must recognize that these ratios were found to be
highly variable at times and in areas where algal growth was at a
maximum.
C. Algae
1. Chlorophyll ^concentrations in the Potomac during 1978 were
low in comparison to 1977 observations and had considerably less vari-
ability. They were unusual in that the maximum bloom condition occurred
during late September when water temperatures were declining rapidly
but river flows were at a minimum. As in 1977, the major algal activity
occurred between river miles 25 and 40, as evidenced by peak chlorophyll
values of 130 - 160 yg/1. Measured values through July and early August
averaged about 50 yg/1 in this critical reach and increased to about
80 yg/1 by late August and early September.
2. Selected samples were collected in the critical zone during the
course of this study for the purpose of identifying the quantitating
ambient algae forms. Dr. James Allison, Maryland Water Resources
Administration, with the assistance of Jeanine Fairchild, EPA/AFO, per-
formed the visual microscopic analysis. During the July and August
portion of the study period, approximately 60 percent of the algal
t ' i
34
-------
population consisted of diatoms. Of the remainder, only 14 percent was
accounted for by blue-green forms of which none was dominant. The
dominant diatom (80 percent of total) was Cyclotella. The chlorophyll a^
varied from about 20 to 100 yg/1 with a mean of 50 yg/1. The total
~)/60 ~/*l6Q
actual cell counts varied from 460 to 36Q. per ml.
In the latter part of the study, when chlorophyll a_ was averaging
about 100 yg/1, there was an abrupt change in the predominant algal
species and the number of cells present. From September 11-28, diatoms
comprised only about 14 percent of the population, although Cyclotella
remained the dominant genus. Blue-green varieties, however, now com-
prised approximately 80 percent of the total population and 87 percent
of the blue-green population was identified as Pseudanabaena catenata,
by Drs. Allison and Sze (Georgetown University). Cell counts for this
alga had risen to the 60,000 - 80,000 per ml range.
3. Pseudanabaena has a remarkable similarity to Oscillatoria,
the predominant form of algae documented in the Potomac during 1977.
Both are filamentous and can be described as being a "box car like"
chain with each unit measuring only a few microns. Perhaps a misidenti-
fication was made in 1977 because of this similarity. It is interesting
to note that this dominant form of algae was also tentatively identified
as Schizothrix during September, 1978.
Pseudanabaena is benthic in origin and may have been initially
cultivated in small or shallow embayments and then washed into the larger
and deeper areas of the Potomac Estuary itself. The organism does not
contain heterocysts and is probably not nitrogen fixing.
4. It is not certain why this bloom of Pseudanabaena proliferated the
35
-------
way it did, when it did. As mentioned previously, there was no radical
change in the nutrient regime immediately preceding the bloom nor was
there clear evidence that one particular macro-nutrient was rate limiting.
Other factors such as: (1) the grazing by zooplankton on competitive
algal forms, (2) the rapidly declining hydrograph during the bloom
period, (3) the availability of silicate for continued diatom predomi-
nance, (4) increased iron concentrations from Blue Plains and (5) light
availability may have important implications and require further investi-
gation.
5. A total of nineteen samples were collected and analyzed to
determine the elemental composition of the phytoplankton population
which, at the time of sampling (September 7-28), was primarily blue-
green algae. The results are tabulated below:
Algal Composition Summary
Range
Average
Standard
Deviation
Mg C
yg Chloro
.015-. 027
.021
.004
Mg N
yg Chloro
.0035-. 0086
.0054
.0012
Mg P04
yg Chloro
.0010-. 0029
.0020
.0005
6. In addition to lab data, gross estimates of the amounts of
organic carbon, nitrogen, and phosphorus within algal cells were also
made using field data collected during the slack water runs. All of
the available 1977-78 algal elemental composition analysis data are
presented in Figures 19 to 21. It can be seen that the laboratory
data from both years compares quite well even though the times, flows,
temperatures and possibly the algae itself were significantly different.
36
-------
CARBON - CHLOROPHYLL RELATIONSHIP
POTOMAC ESTUARY
(1977-1978 DATA)
6.0i
5.0'
4.0-
X 1977 LAB DATA
O 1978 FIELD DATA
Q 1978 LAB DATA
OJ
3.0-
2.0
1.0
o
250
-------
NITROGEN "CHLOROPHYLL RELATIONSHIP
POTOMAC ESTUARY
(1977-1978 DATA)
1.5-
1977 FIELD DATA
X 1977 LAB DATA
O 1978 FIELD DATA
Q 1978 LAB DATA
1.0-
CJ
00
en
i
z
05-
c
TO
E50
-------
PHOSPHORUS- CHLOROPHYLL RELATIONSHIP
POTOMAC ESTUARY
(1977-1978 DATA)
0.6
OS-
0.4.
CO
to
3
a
0.2
0.1
1977 FIELD DATA
X 1977 LAB DATA
O 1978 HELD DATA
El 978 LAB DATA
o
X
m
50
100
ISO
200
250
-------
In the case of phosphorus, estimates based on field data were identical
to the lab measurements. In fact, all 1977 and 1978 phosphorus data
coincided. Both carbon and nitrogen data showed more variability,
particularly in the field estimates.
The relationships contained in Figures 19 - 21 show that in
order to support a bloom with a chlorophyll concentration of 100 yg/1
there would theoretically have to be 2.5 mg/1, 0.6 mg/1 and 0.2 mg/1
of C, N and P04, respectively. These translate to atomic C:N:P ratios
of 100:20:1.
7. Past Potomac data as well as the technical literature have
strongly indicated that algae impart, through their respiration and
decay, a major effect on the BOD,- value. This in turn will have a
similar adverse effect on DO which cannot be ignored during certain
periods of the summer. An attempt to develop the algae (chlorophyll) -
BOD5 relationship was undertaken in the laboratory [2] and the following
results were obtained:
Total Algal Effect - 0.027 mg BOD5
ug Chloro
Algal Decay - 0.019 mg BOD5 (70% of Total)
ug Chloro
Algal Respiration - 0.008 mg BODs (30% of Total)
vg Chloro
Two important points should be made: (1) there is a very
close agreement between the total algal effect on BOD5 and the carbon
content of the algal cells as presented previously (i.e. 0.027 mg BODg
Chloro
vs. 0.025 mg C ), and (2) during the latter stages of the 1977
vg Chloro
40
-------
Potomac study a significant die-off of algae was observed wherein the
BODg increased by 5 - 6 mg/1 and DO dropped about the same amount [1].
Assuming the above relationship for algal decay, this 200 ug/1 reduction
in chlorophyll that occurred should theoretically yield an additional
4 mg/1 of 6005. If the above respiratory effects were included, the
two results would be in close agreement.
D. DO - BOD
1. Minimum DO concentrations measured during the 1978 Potomac
slack water runs were in the range of 4.0 - 4.5 mg/1. These values
generally occurred between Piscataway Creek and Gunston Cove following
two storm events at the end of July. River flows at the time varied
from about 7,000 to 9,000 cfs.
A dramatic improvement in DO was experienced between 1977 and
1978.
2. There is a strong correlation between DO measurements at the
surface and at 5' depth at a given point in time and space. The survey
data were grouped for stations primarily impacted by Blue Plains
(Stations 4, 5, 5A, 6 and 7) as well as for those stations primarily
impacted by algae (Stations 8, 8A, 9, 10 and 10B) and then used for
regression analysis (Figures 22 and 23). The upper group of stations
showed a difference in DO concentrations of about 0.25 mg/1 (surface
being higher) whereas the lower group showed almost identical results.
Segregating the data based upon chlorophyll levels did not change these
results appreciably (Figures 24 and 25).
3. Three additional drogue studies were conducted in the Rosier Bluff
41
-------
ro
12
II
10
9
?8
6 7
I -
16
Q.
Q
~*4\
O
03
2
RELATIONSHIP OF SURFACE AND 5' DO MEASUREMENTS
STATIONS 4.5,5A.6.AND 7 POTOMAC
(JULY 17- SEPTEMBER 27,1978)
Y= I.OIX - 0.296
r = 0.863
i - 11.85
c
c
TO
r\>
ro
2 3 4 5 6 7 8 9 10 II 12
OO - SURFACE (mg/l)
-------
RELATIONSHIP OF SURFACE AND 5' D O MEASUREMENTS
STATIONS 8.8A,9,10, AND IOB-POTOMAC
(JULY 17- SEPTEMBER 13.1978)
co
12
II
10
9
-8
7
i
O
Y= 0.942X + 0.36
r = 0.985
t - 29.76
6 7 8 9 10 I! 12
DO-SURFACE (mg/l)
-------
RELATIONSHIP OF SURFACE AND 5'DO MEASUREMENTS
STATIONS 8. 8A, 9, 10, AND IOB- POTOMAC
(JULY 17- AUGUST 3 &. SEPTEMBER 5.1978)
-pi
-Pi
12-
II
10
9
o
03
o
c
XI
CHLORO a = 20- 60 ug/l
Y = 0.963X 4 0.205
r = 0.99
= 30.4
6 7 8 § TO Tl T2
DO-SURFACE (mg/l)
-------
tn
Q.
051
I
o
03]
2-
!
RELATIONSHIP OF SURFACE AND 5'DO MEASUREMENTS
STATIONS 8,8A, 9,10, AND IOB - POTOMAC
(AUGUST 28- SEPTEMBER 13,1978- EXCLUDING SEPTEMBERS)
12
II
10
9-
CHLORO a* 60- 100 ug/l
Y = 0.792X + 1.552
r = 0.949
t = 8.54
c
3)
m
6 7 8 9 TO Tl T2
DO-SURFACE (mg/l)
-------
to Piscataway reach of the Potomac during 1978. Two of these studies
were of 24 hour duration (6:00 a.m. - 6:00 a.m.) and the third had a
duration of 10 hours (7:00 a.m. - 5:00 p.m.). Both chlorophyll levels
and the amount of diurnal DO variability were unexpectedly low during
each of these drogue studies, as can be seen in Figures 26 and 27.
Chlorophyll levels varied from 30 to 60 yg/1, the change in surface DO
varied from 0.5 to 2.5 mg/1, and the change in bottom DO was 0.5 to 1.5
mg/1. The absolute minimum DO observed during these drogue studies
was about 4.0 mg/1, which again indicates significant improvement over
the preceding year.
4. A special attempt was made to discern differences between
early morning and afternoon DO concentrations at the time and place
of peak chlorophyll concentrations. Data from two successive days was
used for this purpose. Even with chlorophyll at about 140 yg/1, the
diurnal change in surface DO was only between 2.0 and 3.0 mg/1. Again,
absolute minimum DO levels at either surface or bottom did not drop
below the 4.0 - 4.5 mg/1 range. It should be pointed out, however, that
by this time (September 27-28) the water temperature had already de-
creased to about 23°C.
5. Compositing all of the available diurnal DO data collected by
AFO produces the relationships shown in Figures 28 and 29. One set of
data applies to the surface and the other to the bottom. Given a chloro-
phyll concentration of 100 yg/1 upstream of Piscataway and hot sunny
weather one can expect a diurnal DO variation of 4 - 5 mg/1 at the
surface and about 2 mg/1 at the bottom excluding tidal effects. Simi-
larly, when cloudy conditions prevail the surface DO variability drops
to about 1 mg/1.
46
-------
DROGUE STUDY DO DATA
, UPPER POTOMAC ESTUARY .
(ROSIER BLUFF- PISCATAWAY)
JULY 31. 1978 (SUNNY & HOT)
SURFACE
X MID DEPTH
©BOTTOM
ADOsURf 2 l.5mg/l
ADOBOT = I.Omg/l
CHLOROA =25-30jig/l
TEMP. = 27-28*
FLOOD
EBB
FLOOD
EBB
AUGUST 29. I97B (SUNNY A HOT)
SURFACE
XMID DEPTH
©BOTTOM
CHLORO A = 50-60j*9/l
TEMP. =27-29*
FLOOD
EBB
FLOOD
EBB
12 I 2 3 4 5 6 7 8 9 10 II 12 I
HOURS
FIGURE-26
47
-------
DROGUE STUDY DO DATA
POTOMAC ESTUARY (ROSIER BLUFF-RISCATAWAVJ
SEPTEMBER 13, 1978 (MOSTLY CLOUDY &COOL)
SURFACE
XMID DEPTH
0 BOTTOM
-P.
oo
f ^
O
Q
ro
-J 6
O
ADO SURF: = O.Smg/J
&DOBOI £ 0.5mg/l
-X-
EBB
^&-
t SOME SUNLIGHT (
CHLORO a = 50-60^g/I
TEMP.= 25*
FLOOD
10
tftfifc
-------
SUMMARY OF DIURNAL DO DATA
POTOMAC ESTUARY (W.W.BRIDGE TO INDIAN HEAD)
SURFACE DATA
1977-78 DROGUE STUDIES
O PRE 1977 DATA
ESPECIAL 1978 DATA
LEGEND-WEATHER CONDITIONS SUNNY AND
HOT UNLESS OTHERWISE NOTED.
WATER TEMP. ALSO INCLUDED. DATA
COLLECTED ABOVE PISCATAWAY IS
NOT LABELLED.
-P.
vo
10
9
3
2-1
I
C
;o
m
i
M
0>
24
22.5'Q
20
40
60
80 100
CHLOROPHYLL
140
160
180
200
-------
SUMMARY OF DIURNAL DO DATA
POTOMAC ESTUARY (W.W. BRIDGE TO INDIAN HEAD)
BOTTOM DATA
1978 DROGUE STUDIES
O PRE 1977 DATA
E) SPECIAL J977 DATA
LEGEND - WEATHER CONDITIONS SUNNY AND
HOT UNLESS OTHERWISE NOTED.
WATER TEMP. ALSO INCLUDED.
61
5-
4.
i
O
o
3D
m
i
N
to
.27-28
.27-29
27-29Q
25* (CLOUDY!
MSC.l
27-29
UW.W.BR.
OOGUE
'HAL. PT.
20
40
60
60 100
CHLOROPHYLL
120
140
160
-------
6. Valid trends with respect to DO are always difficult to discern
because of a large number of influencing factors present. The inter-
relationship and relative effects of these factors, such as river flow,
water temperature, algae, bacterial populations, etc. are nearly
impossible to consider fully. Nonetheless, a somewhat distinct
improvement in DO concentrations in the Potomac during higher than
normal flow periods is apparent based upon an examination of ten years
of historical data.
A six observation data set collected between August 12-14, 1969
when river flows were about 9,000 cfs showed several DO values in the
range of 2 - 3 mg/1. Average DO values were as low as 3 - 3.5 mg/1.
A year later similar DO concentrations were recorded while flows were
averaging 17,000 cfs.
Another data set composed of two observations (July 15 - 16,
1974) also contained DO values in the vicinity of 3.0 mg/1 at one station.
Flows preceding this sampling were as high as 20,000 cfs.
A third data set collected during July 7-22, 1975 (2-3
observations), however, produced DO concentrations that were comparable
to those of the 1978 survey, i.e. 4-5 mg/1 minimum. Average flows
during this period were about 10,000 cfs.
7. Two projects were undertaken during 1978 to better define the
role of bottom sediments on the DO budget. One was to obtain additional
sediment oxygen demand (SOD) measurements using the same equipment and
procedures as last year and the other was to perform a cursory mapping
and characterization of the bottom sediment using visual means. The
1978 SOD results obtained are shown in the table below:
51
-------
Station Rate Temperature
Bellevue - Virginia Side 3.6 28.0
Opposite Blue Plains New Outfall 2.3 26.0
Buoy N "4" Downstream from Goose Island 3.0 28.2
Woodrow Wilson Bridge - Maryland Side 2.3 22.4
Upstream of Rosier Bluff along
Maryland Shore 3.7 26.5
Broad Creek (Upstream End) 1.4 21.5
(2 Measurements Made) 1.2 22.5
Opposite Little Hunting Creek
(Virginia Side) 3.9 28.0
Dogue Creek (Downstream End) 5.5 25.5
Hallowing Point (Maryland Side) 3.3 26.0
Opposite Occoquan Bay 8.5 24.8
Cockpit Point (Virginia Side) 11.4 29.0
Upstream of Sandy Point (Mid-channel) 3.5 21.0
In addition, both the 1977 and 1978 measured SOD values,
corrected to 20°C by using a temperature correction factor of 1.065,
are presented in Figure 30.
Probing and selected sediment sampling was performed throughout
a grid consisting of 26 transects each of which contained three stations
in the lateral plane. The transects extended from Bellevue to Smith
Point (river mile 10 to 46). The bottom sediment was characterized
(i.e. hard or soft sand, clay, mud, etc.) based upon these observations.
Much of the bottom was found to be soft in nature with sand being the
predominant material. While a mixture of soft mud and clay was also
detected at many stations there was no instance where grossly contaminated
52
-------
TIME PERIOD
1977
o 1978
Z Z
p<
os!
++
POTOMAC ESTUARY WATER QUALITY DATA
FLOW TEMPERATURE
5 P
» §
C x
+ I
o <>
w u
i *
o o
o i
PARAMETER (S)
SEDIMENT OXYGEN DEMAND (SOD)
(A)
VALUES CORRECTED TO 20*C (0 = 1.065)
6-
X
o
^
V
t>
x 2-
(X
0-
-n
O
c
31 (
m
i
o
o
o
9 ° o o
a-0*
. °o '
* oo o CD NIO * m 4 u>
a g __ i _^_*-
) 5 10 15 20 25 30 35 40 45 50 55 60 65 70
MILES BELOW CHAIN BRIDGE
A.F.O. STATION NO.
-------
sludge deposits or other highly suspicious material was present at the
time of this survey.
8. Distributions of BODg obtained during alternate slack water runs
exhibited considerable variability and a low degree of correlation with
DO. In general, BODg concentrations were higher in the reach upstream
from Indian Head where maximum values ranging between 4.0 mg/1 and 8.0
mg/1 were recorded. The upper end of this range was experienced during
the low flow period in September whereas the lower values were produced
by the high flows occurring in July and August. The downstream half of
the study reach (Indian Head - 301 Bridge) showed BODg values in the
range of 1.0 - 4.0 mg/1 with a similar temporal trend as the upper reach.
9. Long-term (i.e. 20 day) BOD analyses were performed, with and
without a nitrification inhibitor, on both river and sewage treatment
plant effluent samples in order to shed light on reaction kinetics and
rates [2], The following first-order reaction rates were obtained from
this study.
River Samples
(no exclusion of ambient algal effects)
CBOD - 0.12/day (base e - 20°C) (Standard Deviation = 0.03)
NBOD - 0.10/day (base e - 20°C) (Standard Deviation = 0.06)
The average ratio of CBODr to BOD5 (no inhibitor) was
determined to be 0.58. (Standard Deviation = .15)
Effluent Samples
CBOD - 0.16/day (base e - 20°C) (Standard Deviation = 0.05)
NBOD - statistically inconclusive because of significant
lag period.
54
-------
Given the kinetic data for the treatment plant effluents, it
has been determined that the CBODult/CBOD5 ratio is about 1.8, which is
quite close to the value (1.75) obtained during the 1977 study. Because
of the aforementioned lag for NBOD, it has further been determined that
there was an appreciable difference between the CBODU, /CBOD,- and the
CBODult/BOD5 ratios. The latter ratio had to be calculated in a dif-
ferent fashion since 5-day BODs were not directly obtained during the
long term lab tests. Its average value, 1.3, was nevertheless identical
to that of last year.
E. Point Source Assessment
1. A summary of all the effluent data collected during this study
is presented in Tables 5 and 6. The first table contains pollutant
concentrations whereas the second contains pollutant loadings.
Blue Plains still constitutes, by far, the largest single point
source in the Washington Metropolitan Area. Of the average total point
source loading, it alone accounts for 85% of the BOD5 (77,000 Ibs/day),
77% of the TOC (45,000 Ibs/day), and 58% of the inorganic P04 (5,700
Ibs/day).
2. An examination of Table 5 reveals that there is considerable
variability in effluent concentrations and quite possibly in treatment
plant efficiency. This is particularly true with respect to BOD5> where
the standard deviation values were 50% or more of the mean for most
facilities. While the data is limited, it does not appear that this
relatively large variability in BOD5 is attributable to storm events or
exceptionally high wastewater inflows. It could, however, be partly
attributable to the inherent imprecision of the test itself.
55
-------
TABLE S
S.T.P. Effluent Data Summary
Pollutant Concentrations
Facility
Blue Plains
Arlington
Alexandria
Piscataway
Lower Potomac
(Pohick Creek)
Westgate
Dogue Creek
Hunting Creek
Flov
(mgd)
308
163-378
49
23
19-26
2
29
23-37
4
17
11-29
4
16
15-18
1
4.2
2.8-8.9
2.1
2.6
2.3-3.2
0.2
4.8
4.3-5.9
0.4
BOD5
'
30.3
9.6-56.2
17.2
23.0
4.5-51.0
15.1
46.5
27.0-72.8
19.0
20.0
9.6-30.5
9.1
11.4
3.6-20.4
6.1
15.3
3.5-27.0
8.0
10.8
6.3-15.6
3.5
15.2
6.0-30.8
8.6
TOC
17.5
13.7-27.6
4.5
13.1
7.4-40.2
8.8
23.8
15.2-36.4
5.3
9.4
4.8-15.1
2.6
16.3
9.3-21.6
3.4
14.0
11.1-21.0
2.9
14.7
8.4-17.6
3.0
12.5
10.3-15.2
1.8
TKN
14.7
9.4-22.1
2.8
19.6
14.4-34.4
5.4
18.9
11.7-24.2
3.0
10.9
7.7-14.6
2.4
19.8
13.6-27.4
3.9
17.3
15.1-20.3
1.6
18.4
14.0-22.4
2.7
18.2
15.1-20.4
1.6
NH.
. i. .mnl'l.. .
1 *g/ I------
13.1
9.4-15.9
1.9
18.6
11.8-34.4
5.7
18.6
10.5-31.5
5.1
10.1
7.7-14.6
2.4
18.7
9.3-27.4
4.8
16.5
14.5-18.9
1.6
17.4
13.6-22.4
2.4
17.2
10.9-20.4
2.5
W>2 + M03
0.5
0.2-0.9
0.2
1.2
0.1-5.8
1.5
0.1
<0.1-0.2
<0.1
5.2
3.0-9.8
1.9
1.3
<0.1-5.7
1.9
0.1
<0.1-0.3
<0.1
1.1
0.9-1.5
0.2
2.2
1.7-2.7
0.4
TP04
4.3
2.8-7.8
1.5
9.6
2.2-17.4
4.3
3.2
0.6-8.2
2.0
2.6
1.8-3.6
0.6
17.1
14.2-22.6
2.8
17.5
9.2-33.0
6.7
0.8
0.6-1.1
0.2
0.8
0.5-1.4
0.3
Inorg N:
Inorg P
Inorg PO^ (by atoms)
2.2 42:1
1.0-3.6
0.9
6.5 20:1
0.4-15.5
4.8
0.7 181:1
<0.1-3.8
1.0
1.5 69:1
0.2-1.9
0.5
14.6 9.5:1
10.0-19.7
2.4
14.9 7.5:1
7.8-21.7
4.2
0.1 1250:1
<0.1-0.2
0.3
0.1 1300:1
<0.1-0.2
<0.1
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
Mean
Range
S.D.
-------
TABLE 6
S.T.P. Effluent Data Summary
Pollutant Loadings (Average)
Facility
Blue Plains
Arlington
Alexandria
Piscataway
Lower Potomac
(Pohick Cr.)
Westgate
Dogue Creek
Hunting Creek
BODr
///d %
77,000
2,900
7,200
1,700
1,000
200
100
400
85
3
8
2
1
Neg.
Neg.
Neg.
TOC
///d %
45,000
2,500
5,800
1,300
2,200
500
300
500
77
4
10
2
4
1
Neg.
1
TKN
///d %
38,000
3,800
4,500
1,500
2,700
600
400
700
73
7
9
3
5
1
1
1
NH
#/d
33,000
3,600
4,400
1,400
2,500
600
400
700
3 %
71
8
9
3
5
1
1
2
N02 +
#/d
1,300
200
30
700
200
Neg.
20
90
N03 TP04
% ///d %
51
8
1
28
8
Neg.
1
3
11,000
1,800
800
400
2,300
600
20
30
65
11
5
2
14
3
Neg.
Neg.
Pi (as P04)
///d %
5,700
1,300
200
200
2,000
500
Neg.
Neg.
58
13
2
2
20
5
Neg.
Neg.
Totals 90,500 58,100 52,200 46,600 2,540 16,950 9,900
-------
3. A ten year trend in wastewaste loadings to the upper Potomac
Estuary is shown in Table 7. Of particular interest is the dramatic
reduction in phosphorus loads and its effect on shifting the N:P ratio
a factor of five fold between 1968 and 1978.
F. Chain Bridge Inputs
1. Tables 8 and 9 present all of the pollutant concentration data
for the Chain Bridge station in chronological order for 1978 and 1977
respectively. In addition, the average concentrations and standard
deviations are presented for comparison purposes.
Although the two summer sampling seasons were significantly
different from the standpoint of river flows (6,300 cfs vs. 1,700 cfs),
it can readily be seen that the average concentrations for most of the
parameters were remarkably similar. The major exception was nitrates
which is "land" related and generally reflects a strong dependency on
river flow. Soluble inorganic phosphorus also appeared to increase in
a similar proportion with flow, although its absolute concentration
values were much lower than nitrates. Because of these proportional
increases, the N:P ratios did not exhibit a dramatic trend as a function
of flow over the range in flows that were monitored. During low river
flow periods both inorganic nitrogen and phosphorus were approaching or
below minimum detection levels on a consistent basis.
2. There is a consistent 0.5 mg/1 of TKN entering the Potomac
Estuary at Chain Bridge of which the majority (>0.4 mg/1) is in the
form of organic nitrogen. Other representative concentration values
at this station are 2.5 mg/1 BODg, 0.3 mg/1 total phosphorus, and 5.0
mg/1 total organic carbon.
58
-------
Inorg Nilnorg P
(by atoms)
TABLE 7
Wastewater Loading Trend
Upper Potomac Estuary
Parameter
Flow (cfs)
BOD5 (#/d)
TOC (#/d)
TKN (#/d)
NH3 (#/d)
N02 + N03 (#/d)
TP04 (#/d)
Pi as P04 (#/d)
1968
320
136,000
100,000
55,000
41,000*
3,700
71,000
46,000**
1977
360
74,000
82,000
49,000
43,000
1,800
22,000
16,000
1978
405
90,000
58,000
52,000
47,000
2,500
17,000
9,900
6.8:1
20:1
34:1
*Assume 75% of TKN (based on other historical data)
**Assume 65% of TPO. (based on other historical data)
59
-------
TABLE 8
1978 Chain Bridge Data
Pollutant Concentrations
Date
7/17
7/19
8/1
8/3
8/14
8/16
8/28
8/30
9/5
9/11
9/13
9/25
9/27
Avg.
S.D.
Flow
6,050
6,090
9,330
7,190
16,500
14,500
3,250
4,040
5,530
2,660
2,760
2,290
2,190
6,340
4,610
TOC
3.3
4.7£
6.22
3.78
5.99
5.4
3.3
3.3
5.67
5.93
6.95
3.55
8.17
5.1
1.6
TKN
.45
.49
.47
.5
.3
.46
.45
.36
.87
/54
.46
.67
.62
.51
.14
Part.
Org N
0
.21
.27
.14
.07
.10
.09
.13
-
.01
0
.07
.07
.10
.08
Sol.
Org N
.39
.24
.16
.27
.19
.32
.28
.19
-
.45
.38
.56
.51
.33
.13
NH3
.06
.04
.04
.09
.04
.04
.08
.04
-
.08
.08
.04
.04
.06
.02
N02 +
N03
.6
.73
.27
1.08
1.08
1.18
.2
.15
.91
.42
.4
.69
.58
.64
.35
TP04
.21
.24
.87
.37
.67
.7
.2
.2
.25
.27
.28
.22
.21
.36
.23
Sol.
Org P04
0
.02
.0
.08
.02
.05
-
.05
.06
.06
.08
.07
-
.04
.03
Sol.
Inorg PO^
.04
.04
.04
.12
.2
.24
.04
.04
.04
.06
.05
.09
.04
.08
.07
N:P
no
130
53
66
38
35
47
33
-
56
65
55
105
66
32
BOD5
3.7
-
0.9
-
1.6
-
2.9
4.7
-
2.7
-
1.9
2.6
1.3
DO
8.26
8.5
7.2
7.73
8.35
7.8
7.88
7.7
8.05
8.17
8.1
9.0
9.13
8.14
.53
..nloro
31
52
43
24
-
-
31
27
42
24
39
21
27
33
9.8
-------
TABLE 9
1977 Chain Bridge Data
Pollutant Concentrations
Date
7/18
7/20
7/25
7/27
8/1
8/3
2 8/22
8/24
8/29
8/31
9/6
9/8
Avg.
S.D.
Flow
2,140
1,740
2,710
1,990
1,700
1,340
1,790
2,550
970
1,010
1,090
1,170
1,680
590
TOC
8.77
5.81
1.12
2.76
8.62
4.45
7.84
4.08
2.27
3.47
3.71
12.3
5.4
3.3
TKN
.4
.74
.49
.46
.41
.44
.62
.48
.47
.47
.46
.46
.49
.10
Part.
Org N
.28
.26
.17
.2
.22
.16
.32
.13
.14
.01
.19
.16
.19
.08
Sol.
Org N
.08
.4'
.29
.26
.2
.19
.30
.34
.32
.43
.25
.23
.27
.10
NH3
.05
.09
.03
0
0
.09
0
.02
0
.03
,03
.07
.03
.03
N0? +
N03
0
.05
0
0
0
.14
0
.06
0
.05
0
.07
.03
.04
TP04
.32
.26
.26
.29
.23
.23
.29
.25
.22
.22
.2
.21
.25
.04
Sol.
Org P04
.1
.05
.07
.1
.07
.08
.08
.08
.07
.08
.08
.04
.08
.02
Sol.
Inorg P04
0
.03
0
0
0
0
0
0
.01
.01
0
.05
.01
.01
N:P
U.D.
32
U.D.
U.D.
U.D.
U.D.
U.D.
U.D.
0
54
U.D.
19
41
.
BOD5
2.5
3.2
1.9
1.5
3.0
1.7
3.4
4.0
3.0
2.8
2.0
2.0
2.6
.8
DO
6.73
6.43
7.21
7.97
7.38
7.37
7.78
7.91
7.62
7.22
7.61
7.7
7.41
.46
Chi oro
31.5
34.5
42
52.5
12
25.5
91.5
79.5
34.5
19.5
46.5
45
43
23
-------
3. Table 10 presents a ten year loading trend for Chain Bridge.
Substantial reductions, ranging between 25 and 60 percent, occurred
during this period for several of the water quality constituents,
including BOD^ and phosphorus. It is important to note too that the
ratio of inorganic nitrogen to phosphorus changed by almost a factor
of two.
G. Urban Inputs
1. For purposes of this report an attempt was made to develop crude
(order of magnitude) estimates of pollutant loads entering the Potomac
Estuary from the highly urbanized portion of the Washington metropolitan
complex during this study period. These estimates, which distinguish
between combined sewer overflows and other runoff conveyed through a
storm sewer system, were based upon compositing and examining (without
the aid of a model) a variety of data collected and reported by the
following:
O'Brien & Gere, Consulting Engineers [3]
Roy Weston, Consulting Engineers [4]
Metcalf & Eddy, Consulting Engineers [5]
Northern Virginia Planning District [6]
Virginia Polytechnic Institute [7]
Washington Council of Governments [8]
2. Table 11 depicts the combined sewer and storm sewer BOD,
nitrogen, and phosphorus loadings for each of the appreciable storm
events recorded at Washington National Airport. It can be seen that
the storm sewer loads are quite significant, far overshadowing the
62
-------
TABLE 10
Pollutant Loading Trend
Potomac River at Chain Bridge
Parameter
Flow (cfs)
BOD5 (#/d)
TOC
TKN
NH3
N02 + N03
TP04 (as P04)
Pi (as P04)
Inorg N:Inorg P
1968
2,780
52,800
87,500
14,500
1,800
1,500
4,800
700**
32:1
1977*
1,680
23,000
49,000
4,600
480
1,400
2,200
260
49:1
1978*
6,350
88,000
174,000
11,500
1,700
18,000
13,000
2,500
54:1
***
2,780
38,000
80,000
7,500
800
3,800
4,200
620
50:1
(by atoms)
*Based on regression analysis using 1977-79 data base
**Assume 15% of TPO, (based on other historical data)
***Estimated (regression analysis) for same flow as 1968
(i.e. 2,780 cfs)
63
-------
Date
7/30
7/31
8/4
8/5
8/9
8/11
8/13
8/27
8/30
9/12
9/22
TABLE 11
Estimated Urban Loadings During
1978 Study Period
(based on area of 300 mi2 or 192,000 ac)
Combined Sewers
Rainfall
(in)
0.35
0.85
0.50
0.45
0.30
0.60
1.20
0.35
2.00
0.55
0.25
BOD5
22
57
33
30
17
40
77
22
118
37
13
TN
2
6
3
3
2
4
8
2
12
4
1
TP
103
1
2.5
1
1
1
2
4
1
6.5
1.5
0.5
Storm Sewers
BOD5
Itr
250
490
330
300
210
380
610
250
810
350
180
TN
26
48
34
32
24
38
58
26
78
36
21
TP
v
8
18
11
10
6
13
26
8
43
12
5
TOTALS 7.4 466 47 22 4,160 421 160
64
-------
combined sewer overflows. This is'due to the fact that a runoff area
of 300 mi2 or 192,000 acres (approximately the area within the Capital
Beltway) was assumed for storm water inputs whereas combined sewers
only serve an area of about 12,000 acres.
3. The relative significance of all major load input categories
based upon a total mass emission during the study period is presented
in Table 12. Of interest to note is the similiarity between, and the
dominance of point source and upper basin loads. Even their N:P ratios
are remarkably close. The upper basin loads are extremely significant
because of the high flows experienced during portions of the study
period. Urban inputs are also very important with respect to all three
parameters, expecially BOD. Their loads take on added importance when
it is considered that they are introduced in only about a dozen days or
1/6 of the entire study period.
65
-------
TABLE 12
Delineation of Major Pollutant Loads
Upper Potomac Estuary
(1978 Study Period)
Parameter
BOD5
Total N (Ibs)
Total P (Ibs)
Point Source
6.6 x 106
4.0 x 106
0.4 x 106
Input Category
Upper Basin CSO Urban
7.1 x 106 4.7 x 105 4.2 x 106
3.8 x 106 0.5 x 105 0.4 x 106
0.39 x 106 0.2 x 105 0.16 x 106
66
-------
REFERENCES
1. Assessment of 1977 Water Quality Conditions in the Upper Potomac
Estuary, by Leo J. Clark and Stephen E. Roesch, July 1978
2. Biochemical Studies of the Potomac Estuary - Summer 1978,
by Joseph Lee Slayton and E. Ramona Trovato, May 1979
3. Phase 1 - Combined Sewer Overflow Study, Potomac - Anacostia
River System, by O'Brien and Gere Engineers, March 1979
4. Combined Sewer Overflow Abatement Alternatives, Washington, D.C.,
by Roy F. Weston, Inc., August 1970
5. Reconnaissance Study of Combined Sewer Overflows and Storm
Sewer Discharges, by Metcalf and Eddy Engineers, March 1973
6. Occoquan/Four Mile Run Non-Point Source Correlation Study,
prepared by Northern Virginia Planning District Commission and
Department of Civil Engineering, Virginia Polytechnic Institute,
July 1978
7. Impact of Urban Runoff on Water Quality in the Occoquan Watershed,
by Clifford W. Randall, Thomas J. Grizzard and Robert C. Hoehn,
Department of Civil Engineering, Virginia Polytechnic Institute -
Bulletin 80, May 1978
8. Grant Application Report for Urban Runoff Demonstration Project,
prepared by Washington Council of Governments, May 1979
67
-------
APPENDIX
68
-------
MILES BELOW CHAIN BRIDGE
to
w
c
-------
DO ISOPLETH, Mg/l (5')
POTOMAC ESTUARY - 1978
601
17 21 25 29 2 6 10 14 18 22 26 30 3 7 II 15 19 23 27
JULY AUGUST SEPTEMBER
70
-------
CHLOROPHYLL a. ISOPLETH , jig/I
POTOMAC ESTUARY - 1978
17 21 25 29 2 6 10 14 18 22 26 30 3 7 II 15 19 23 27
JULY AUGUST SEPTEMBER
71
-------
NH3 ISOPLETH. Mg/l
POTOMAC ESTUARY - 1978
60i
55-
17 21 25 29
JULY
10
14 18 22 26 30
AUGUST
7 II 15
SEPTEMBER
19 23 27
72
-------
N02 + N03 ISOPLETH, Mg/l
POTOMAC ESTUARY - 1978
60 n
55
50
45
17 21 25 29 2
JULY
6 10 14 18 22 26 30 3 7 II 15 19 23 27
AUGUST SEPTEMBER
73
-------
TOTAL PHOSPHORUS (os PO4) ISOPLETH, Mg/l
POTOMAC ESTUARY - 1978
60 -i
55-
17 21 25 29 2 6 10 14 18 22 26 30 3 7 II 15 19 23 27
JULY AUGUST SEPTEMBER
74
-------
FILTERED INORGANIC PHOSPHORUS (as PO4) ISOPLETH , Mg/l
POTOMAC ESTUARY - 1978
601
55-
17 21 25 29
JULY
10 14 18 22 26 30 3
AUGUST
7 II 15 19
SEPTEMBER
23 27
75
-------
BOD5 ISOPLETH, Mg/l
POTOMAC ESTUARY - 1978
10 14 18 22 26 30 3
17 21 25 29 2
JULY
AUGUST
SEPTEMBER
76
-------
TOC ISOPLETH, Mg/l
POTOMAC ESTUARY - 1978
17 21 25 29
JULY
10 14 18 22 26 30
AUGUST
7 II 15 19 23 27
SEPTEMBER
77
-------
STATION LUCATICN RMI (=MllES BELLW CHAIN BRIDGE)
CO
1 ....
1-A ....
3 ....
5 ....
5-A ....
10 ....
10-B ....
11 ....
12 ....
13 ....
14 ....
15-A ....
16 ....
.... MAINS PUINT
.... RUSlbR BLUf-F
.... DttP P01M
.... XT. 301 BK10GE
b.9
7.6
10.0
12.1
15.2
22.3
34.0
3fe.O
42.5
62.4
-------
$$«$«*$«$<:******** S*****************************************
PDIOMAC RIVER DATA FDR JULY 17, 1978
STA. RHI TEMP TURB SECCH1 PH SALIN CUND TDC TOCF TKN TKNF NH3 N02N03 TP04 TP04F PI CHLOKO L iD5 BOD20 00 DU ( 5 }
(C) (IN) (PPI) (H&/LJ (MG/Ll (MG/L) (MG/L) (UG/LJ. (MG/L) (MG/LJ
P8 0.0 =»$**
P4 1.9 Z5.9
1 3.4 26.6 9.2 32.0
1A 1.9 27.2 8.5 26.0
2 5.9 26.9 10.3 20.0
3 7.6 26.6 10.0 22.0
4 10.0 26.* 10.2 26.0
5 12.1 26.3 10.5 20.0
5A 13.6 27.1 9.9 24.0
6 15.2 27.0 13.9 23.0
7 18.4 26.3 10.5 22.0
8 22.3 26. 4 7.8 28.0
8A 24.3 26.5 8.5 27.0
9 26.9 26.5 5.5 27.0
10 30.6 26.1 10.0 28.0
10B 34.0 26.1 10.0 28.0
11 38.0 25.8 9.5 26.0
12 42.5 25.9 8.5 32.0
13 45.6 25.8 9.8 30.0
14 52.4 25.6 19.9 14.0
15 58.6 25.5 29.9 15.0
15A 62.8 25.0 20.4 18.0
16 67.4 25.2 15.0 20.0
9.5 **** **** ***** ***** 3.3C 3.30 0.45 0.45 0.06 0.60 0.21 0.04 0.04
7.5 32.0 6.3 0.15 0.39 2.80 2.60 0.25 0.22 0.^)4 0.59 0.23 0.04 0.04
8.4 0.15 0.40 3.10 2.70 0.29 0.22 0.03 0.54 0.20 0.04 0.04
8.3 0.13 0.41 3.50 3.00 0.23 0.23 0.02 0.56 0.20 0.04 0.04
8.2 0.19 0.36 3.50 3.50 0.26 0.24 0.02 0.60 0.23 0.04 0.04
8.2 0.15 0.34 2.80 2.20 0.27 0.27 0.03 0.66 0.25 0.04 0.04
8.0 0.16 0.39 3.80 2.60 0.32 0.31 0.06 0.77 0.24 0.04 O.C4
7.8 0.14 0.36 3.9C3.1C 0.71 0.64 U.40 O.faV 0.43 0.13 0.12
7.4 0.15 0.37 3.50 3.30 1.60 1.48 1.22 0.90 0.49 0.17 0.15
7.4 0.17 0.37 3.50 3.20 1.24 1.12 0.86 0.91 0.53 0.19 0.16
7.5 0.13 0.37 3.70 3.10 1.15 1.08 0.77 0.9b 0.21 0.15 0.13
7.3 0.17 0.47 3.80 3.50 1.14 1.05 0.69 0.95 0.16 0.13 0.12
7.3 0.14 0.36 3.30 2.90 1.04 1.03 0.65 0.97 0.36 0.11 0.11
7.4 0.13 0.36 4.40 4.40 0.93 0.93 0.59 0.96 0.32 0.09 O.C9
7.6 0.15 0.36 4.20 3.70 0.69 0.65 0.29 0.90 0.38 0.09 O.C6
7.5 0.15 0.39 3.80 3.40 0.54 0.54 0.20 0.98 0.36 0.09 0.08
7.8 0.21 0.39 4.40 3.50 0.55 0.55 0.55 0.95 0.46 0.46 0.44
7.7 0.19 0.42 4.30 2.80 0.52 0.52 0.07 0.95 0.42 0.14 0.13
8.0 0.19 0.38 3.40 3.10 0.40 0.40 0.04 0.74 0.46 0.18 0.17
8.0 1.54 0.72 3.40 3.00 0.39 0.38 0.05 0.39 0.72 0.26 0.26
7.6 1.46 2.65 3.40 2.60 0.25 0.25 0.05 0.29 0.61 0,26 0.26
7.4 3.48 4.81 3.BO 3.30 0.29 0.26 0.05 0.24 0.45 0.22 U.22
7.3 3.54 6.06 3.10 2.70 0.27 0.22 0.05 0.14 0.43 0.21 0.21
31.5 **** **** 8.26 *****
45.0 **** **** 8.29 6.lb
40.5 **** **** 8.37 7.97
33.0 **** **** 8.28 7.2
-------
*3*S*$$,>$«$$$$S,S$0 ******************************************
POTOMAC RIVER DATA FOR JULY 19, 1978
**«**«*«**«*«*«««***«*«********««**«***********«***«***#*«**
STA.
P8
P4
1
U
2
3
4
5
00 5A
0
6
7
8
8A
9
10
10B
11
12
13
14
15
15A
16
RM1
0.0
1.9
3.4
4.9
5.9
7.6
1C.O
12.1
13.6
15.2
ie. 4
22.3
24.3
26.9
30.6
34.0
38.0
42.5
45. B
52.4
5b.6
62.8
67.4
TEMP
(C)
****
27.0
27.0
27.0
27.0
27.2
27.0
27.0
27.0
27.0
26.8
27.0
27.0
27.0
26. B
27.0
26.2
24.0
27.5
27.0
26.9
26.5
26.5
TURB
8.8
6.5
6.5
6.5
8.3
7.2
9.9
9.9
10.0
9.9
10.2
9.8
8.5
9.5
8.5
8.9
6.9
7.9
6.0
14.9
18.0
25.0
14.0
SECCH1
(IN)
****
30.0
30.0
30.0
24.0
24.0
18.0
18.0
18.0
24.0
24.0
24.0
24.0
24.0
22.0
24.0
24.0
24.0
26.0
12.0
12.0
14.0
20.0
PH
**#*
8.9
6.8
8.9
8.8
8.8
8.7
8.6
8.1
7.9
7.8
7.9
8.0
8.0
8.4
8.3
8.4
8.5
8.6
8.0
7.6
7.4
7.1
SAL IN
(PPT)
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
0.18
0.46
1.62
3.30
3.70
CO NO
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
**$$*
0.40
0.84
2.96
5.84
6.50
TOC TOCF
( KG/L )
4.78 3.74
4.66 2.59
4.47 3.53
4.68 3. 01
4.99 3.53
4.26 2.70
5.83 3.53
5.62 3.22
4.89 3.74
4.89 3.53
3.95 3.95
4.05 3.43
4.37 3.22
5.41 4.47
6.56 3.64
5.10 5.10
5.73 4.05
4.47 3.01
5.10 4.47
4.5t 3.53
4.0t> 3.64
3.22 3.22
4.26 3.32
TKN TKNF
(MG/L)
0.49 0.28
0.28 0.16
0.41 0.14
0.36 0.19
0.32 0.17
0.34 0.14
0.35 0.19
0.55 0.40
1.11 0.86
1.33 1 .09
1.17 1.02
1.13 1.01
0.96 0.90
0.89 0.79
0.65 0.45
0.55 0.45
0.38 0.33
0.36 0.29
0.34 0.26
0.29 0.26
0.24 0.19
0.17 0.17
0.17 0.17
NH3 NU2NG3
(MG/L)
0.04
0.02
0.02
0.02
0.02
0.02
0.02
0.21
0.95
0.85
0.77
0.72
0.51
0.46
0.15
0.14
0.03
0.02
0.02
0.03
0.04
0.05
0.03
0.73
0.69
0.66
0.70
0.76
0.68
0.67
0.72
0.76
0.79
0.97
1.04
1.07
1.07
1.01
1.04
1.00
0.95
0.77
0.53
0.31
0.20
0.17
TP04
0.24
0.22
0.18
0.20
****
0.20
0.25
0.36
0.53
0.54
0.44
0.28
0.36
0.34
0.30
0.34
0.35
0.38
0.40
0.59
0.52
0.51
0.43
TP04F PI CHLORD
(MG/L) (UG/L)
0.06
0.04
0.04
0.05
0.06
0.04
0.05
0.08
0.17
0.18
0.13
0.16
0.06
0.06
0.05
0.06
0.08
0.10
0.13
0.27
0.25
0.22
0.22
0.04
0.04
0.04
0.04
0.04
O.C4
0.04
0.11
0.12
0.09
0.09
0.04
0.06
0.05
0.03
0.04
0.08
0.10
0.12
0.27
0.25
0.22
0.22
52.5
46.5
45.0
55.5
40.5
48.0
52.5
51.0
43.5
60.7
54.0
37.5
46.5
37.5
64.5
7.5
21.0
55.5
52.5
30.0
9.0
9.0
15.0
8005 BQ020
(MG/L)
3.7
3.4
3.3
2.9
2.8
2.8
3.6
2.8 .
3.3
4.7
3.9
3.7
4.0
4.1
3.7
2.6
2.6
3.1
2.6
1.3
1.5
0.8
1.2
****
****
****
**«*
****
«*«*
*«**
****
****
«*«*
***«
****
«**«
****
****
****
****
*«««
**«*
****
****
****
**«*
DO DQ(5)
(MG/L)
8.51
9.82
9.46
11.45
10.26
10.78
10.04
9.30
7.91
7.71
7.46
7.59
8.47
8.39
9.75
6.95
9.33
9.16
9.34
6.25
5.01
4.52
5.41
*****
10.00
9.58
11.37
10.24
10.78
10.11
9.05
7.77
7.63
7.52
7.44
tt.54
8 .34
9.75
8. 83
9.22
8.95
9.38
6.13
5.00
4.43
5.16
-------
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06'S iB'S **** #*** 5'IE »0'0 90'0 6Z'0 SE'O 81'0 OZ'O BE'O OO'I 6S'E S9'0 8Z'0 i't O'OZ S'l 6'f)Z I'Zl S
96*S 89'9 **** **** q'ZZ *0'0 WO EZ'O 9£'0 81'0 03*0 8E'0 OO't SE'Z S9'0 ^E'O S'i O'M 5'9 Z'8Z 0*01 *
*'£ t
»><>'L Z9'i **** **** S'O* (rO'O ">0'0 8Z '0 tE'O ZO'O OZ'O *£'0 OO'I EO'E 99'0 ZE'O L'L O'lt Z'OI 6'9Z 6'I »d
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(s>oa no ozaoa sooa oaoiHD id dt>odi
-------
POTOMAC RIVER DATA FOR AUGUST 3, 1978
$***$*$************«$*«**$**»******«***********«***********
su.
P8
P4
1
1A
2
3
4
5
00 5A
6
7
8
6A
9
10
10B
11
12
13
1*
15
15A
16
RHI
O.C
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
16.4
22.3
24.3
26.9
30.6
34.0
36.0
42.5
45.8
52.4
58.6
62.8
67.4
TEMP
(C)
****
****
26.4
26.7
27.0
26.6
26.9
27.5
27.6
27.6
27.8
27.8
28.0
28.1
28.3
28.1
27.5
28.0
28.1
28.0
27.8
27.5
27.2
TURB
25.0
14.0
15.0
14.0
9.9
15.0
15.0
14.9
15.0
9.9
5.8
6.5
7.0
8.0
7.5
7.0
9.9
9.5
9.0
9.5
9.8
10.0
5.3
SECCHI
(IN)
***«
12.0
18.0
22.0
22.0
20.0
22.0
22.0
24.0
26.0
24.0
26.0
26.0
26.0
32.0
24.0
23.0
24.0
23.0
18.0
22.0
20.0
32.0
PH
***«
7.6
7.6
7.7
7.9
7.6
7.6
7.4
7.5
7.3
7.3
7.4
7.2
7.3
7.4
*4**
7.6
7.8
7.8
7.6
7.5
7.3
7.2
SAL1N
(PPT)
*****
*****
*****
*****
*****
*****
*****
*****
0.20
0.25
0.30
0.30
0.38
0.30
0.20
0.21
0.90
0.90
1.10
0.90
4.10
4.70
4.73
CO NO
*****
*****
0.52
0.50
0.56
0.60
0.60
0.60
0.53
0.60
0.60
0.61
0.65
0.60
0.61
0.58
0.53
0.60
0.62
1.70
4.76
7.40
8.40
IOC TOCF
( KG/L )
3.78
5.13
4.00
3.66
3.19
3.03
3.51
3.41
3.24
3.46
3.30
2.60
3.78
3.68
3.41
4.27
6.42
3.14
3.57
2.54
2.87
2.54
2,87
1.00
1.00
1.15
1.00
1.00
1.00
1.00
3.19
1.00
1.00
1.00
1 .00
1.00
1.47
1.00
1.00
1.15
1 .00
1.00
1.00
1.00
2.49
1.00
TKN TKNF
(MG/U
0.50
0.45
0.39
0.36
0.34
0.39
0.34
1.01
0.98
1.02
1.26
1.38
1.06
0.88
0.59
0.57
0.54
0.45
0.39
0.29
0.25
0.24
0.20
0.36
0.34
0.34
0.25
0.20
0.20
0.20
0.64
0.70
0.76
1.03
1.12
0.87
0.50
0.34
0.29
0.27
0.20
0.20
0.20
0.20
0.20
0.20
NH3 N02N03
(MG/L)
0.09
0.07
0.08
0.06
0.04
0.07
0.08
0.64
0.65
0.69
1.01
1.12
0.59
0.23
0.04
0.04
0.06
0.04
0.05
0.04
0.04
0.04
0.04
1.08
1.09
1.06
0.88
0.83
0.60
0.44
0.38
0.34
0.21
0.37
0.54
1.16
1.24
1.35
1.08
0.90
0.67
0.64
0.49
0.31
0.20
0.14
TP04
0.37
0.33
0.33
0.30
0.25
0.32
0.32
0.50
0.46
0.43
0.41
0.37
0.38
0.43
0.38
0.40
0.39
0.46
0.51
0.64
0.54
0.54
0.46
TP04F
(MG/L:
0.20
0.20
0.19
0.13
0.11
0.12
0.10
0.22
0.19
0.18
0.19
0.19
0.16
0.16
0.14
0.14
0.18
0.25
0.27
0.42
0,39
0.36
0.34
PI CHLORO
1 (UG/L)
0.12
0.12
0.12
0.06
0.04
0.04
0.04
0.14
0.12
0.14
0.13
0.12
0.09
0.08
O.C6
O.OS
0.11
0.19
0.23
0.36
0.34
0.32
0.29
24.0
25.5
22.5
28.5
45.0
33.0
40.5
36.0
37.5
31.5
31.5
36.0
43.5
82.5
55.2
63.0
52.5
46.5
51.0
27.0
28.5
25.5
27. Q
BOD5 BOD20
(MG/L)
0.9
0.7
0.6
0.8
1.2
1.1
1.3
1.5
1.4
1.2
1.5
3.4
3.5
3.1
1.9
1.6
1.4
1.1
1.1
0.5
0.6
0.7
0.8
****
****
«*««
****
****
«***
****
****
*«**
****
**«*
««««
*«*«
«**«
«***
****
****
«***
****
***«
«***
****
*«<*
00 DO (5)
(MG/L)
7.73
7.62
7.45
7.35
7.93
6.89
6.71
5.98
5.74
5.26
4.81
4.52
3.99
5.46
5.26
5.55
6.18
6.11
5.66
5.68
4.78
3.99
5.26
*****
7.52
7. 48
7.52
7.86
7.07
6.81
6.18
5.B2
5. 11
4.76
4.50
4.39
5.12
5.50
5.77
6.34
6. 11
5.9!>
5.33
5.03
4.17
5.10
-------
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-------
*«**«***««*#**«*«*«***«*«**«****«******«**$**«*«**«««*****$*
POTOMAC RIVER DATA FOR AUGUST 16, 1976
************************************************************
STA.
P8
P4
1
1A
2
3
4
5
5A
6
7
8
8A
9
10
108
11
12
13
14
15
15A
16
RMI
0.0
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
ie.4
22.3
24.3
26.9
30.6
34.0
38.0
42.5
45.8
52.4
58.6
62.8
67.4
TEMP
(C)
***«
27.5
27.1
27.7
27.9
28.0
26.2
28.5
27.5
28.6
28.1
28.0
27.7
28.1
28.3
29.0
28.8
29.1
29.1
29.0
27.7
28.0
28.3
TURB
20.0
18.0
20.0
20.5
18.0
20.0
18.0
18.0
25.0
18.3
18.0
17.0
16.5
14.0
14.0
10.0
9.2
10.0
7.0
7.3
10.0
10.0
9.9
SECCHI
(IN)
****
6.0
8.0
12.0
12.0
10.0
12.0
13.0
11.0
12.0
12.0
22.0
15.0
13.0
18.0
20.0
22.0
22.0
25.0
13.0
13.0
18.0
26.0
PH
****
7.8
7.8
7.8
7.9
7.9
7.9
7.9
****
7.6
7.4
7.5
7.4
7.5
7.6
7.7
7.9
8.2
7.7
7.9
7.8
7.5
7.6
SALIN
(PPT)
*****
*****
*****
*****
*****
*****
0.65
0.60
0.62
0.60
0.65
0.65
0.60
0.56
0.60
0.65
0.65
0.60
0.70
0.70
1.98
4.00
4.40
COND
*****
*****
*****
*****
*****
*****
1.40
1.35
1.32
1.38
1.30
1,30
1.39
1 .30
1.30
1.30
1.34
1.34
1.38
1.40
3.6B
7.40
7.90
TOC TOCF
(KG/L)
5.40 1 .95
4.52 1 .00
4.30 1.45
3.31 1.07
4.16 1 .00
2.10 1 .00
3.04 1.00
3.86 1.00
5.45 2.08
5.40 1 .07
4.46 1.73
5.45 1,29
7.21 1.40
5.84 2,83
5.40 2.61
6.22 2.39
3.86 3,74
5.89 2.50
4.74 1 .67
5.78 1 .00
4.08 1.51
4.19 1.00
4.79 1,73
TKN TKNF
(MG/L)
0.46 0.36
0.33 0.30
0.37 0.31
0.33 0.30
0.26 0.25
0.24 0.24
0.23 0.23
0.31 0.26
0.30 0.30
0.58 0.55
0.71 0.65
0.75 0.70
0.70 0.66
0.66 0.54
0.69 0.54
0.54 0.39
0.44 0.32
0.44 0.31
0.45 0.31
0.41 0.32
0.44 0.32
0.35 0.32
0.34 0.29
NH3 N02N03
(MG/L)
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.06
0.06
0.31
0.40
0.43
0.38
0.27
0.24
0.12
0.04
0.04
0.04
0.04
0.04
0.05
0.04
1.18
1.17
1.17
1.18
1.19
1.18
1.10
1.05
1.04
0.97
0.91
0.84
0.82
0.77
0.77
0.76
0.77
0.77
0.81
0.63
0.51
0.32
0.27
TP04
0.70
0.49
0.59
0.40
0. 35
0.34
0.34
0.39
0.3b
0.47
0.44
0.3«
0.36
0.38
0.37
0.37
0.37
0.38
0.36
0.51
0.49
0.49
0.46
TP04F
(MG/Li
0.29
0.30
0.32
0.28
0.24
0.21
0.23
0.25
0.25
0.29
0.25
0.24
0.21
0.20
0.19
0.11
0.15
0.15
0.17
0.31
0.31
0.38
0.36
PI
0.24
0.25
0.27
0.22
0.20
0.18
0.19
0.21
0.21
0.25
0.21
0.18
0.16
0.14
0.13
0.10
0.09
0.08
0.10
0.22
0.32
0.34
0.32
CHLORO
(UG/L)
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
BOD5 B0020
(MG/L)
1.6
0.6
0.2
0.3
0.7
0.4
0.5
1.1
0.7
1.5
1.9
2.2
2.3
3.0
2.8
3.2
2.8
3.2
2.3
1.3
0.8
0.8
1.4
«***
***«
****
****
*«**
****
****
****
****
****
****
****
****
«***
****
****
****
*«**
****
*«**
«***
*«*«
****
00 00(5)
(MG/L)
7.80
7.H7
7.79
7.71
7.92
7.71
7.74
7.47
7.05
7.09
6. 13
5.96
4.92
5.66
6.39
5.55
6.18
7.77
6.75
6.44
4.94
3.92
5.59
8.01
7.8?
7.79
7.71
7.79
8.04
7. 99
7. 12
7.40
6.6t>
5.H4
5.79
o. 7)
6.45
7.47
7.53
8.64
7.79
6 .01)
5.24
4.42
3.68
5.40
-------
******************e««*****4************«****************#*«e
PDTUMAC RIVER DATA FDR AUGUST 28, 1978
$ «********«*$*«*«*«**«*«**********#*£***********«»*«****#»**
S1A.
P8
P4
1
1A
2
3
4
5
oo 5A
en ^
6
7
8
8A
9
10
108
11
12
13
H
15
15A
16
RMI
0.0
1.9
3.4
4.9
5.9
7.6
1C.O
12.1
13.6
15.2
18. 4
22.3
24.3
26. S
30.6
34.0
36.0
42.5
45. B
52.4
56.6
62.6
67.4
TEMP
(C)
****
26.8
29.6
28.6
28.5
27.9
28.2
28. 4
28.5
28.3
28.8
28.8
28.8
28.7
28.5
28.1
28.5
28.4
26.4
28.0
28.3
26.2
29.7
TURB
5.5
6.8
6.5
6.0
6.5
6.0
6.5
6.3
6.0
5.5
6.0
8.5
6.5
10.0
9.9
7.3
10.0
8.0
6.0
9.0
7.0
7.0
7.0
SECCHI
(IN)
***«
****
22.0
26.0
26.0
22.0
28.0
23.0
29.0
29.0
28. C
24.0
21.0
22.0
24 .0
24.0
24.0
21.0
24.0
24.0
22.0
26.0
30.0
PH
«***
9.0
9.2
8.9
9.0
8.5
8.0
8.1
7.8
7.9
8.2
8.7
8.5
8.6
8,3
8.2
8.6
8.7
8.7
6.1
7.8
8.1
7.3
SALIN
(PPT)
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
0.16
0.34
2.32
3.63
5.12
6.40
CUND
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
0.32
0.26
0.33
0.72
4.21
6.60
9.15
11.86
TOC 70CF
(hG/L)
3.30
2.53
3.24
3.52
3.3C
3.47
2.64
3.44
4.13
2.92
3.97
4.41
4.46
5.52
4.41
5.60
4.19
5.41
5.35
3.52
3.J4
5.96
4,24
1.00
1.00
J .00
1.00
1.00
1.00
1.00
2.14
1 .86
1.00
1.00
1,00
1.00
1.03
1.00
1.00
1.00
1.00
1.00
1 .00
1.00
1.47
i.oo
TKN TKNF
(MG/L)
0.45
0.39
0.28
0.26
0.39
0.35
1.42
1.57
1.74
1.55
1.12
0.53
0.56
0.43
0.52
0.48
0.50
0.42
0.39
0.33
0.30
0.37
0.30
0.36
0.20
0.20
0.20
0.20
0.30
1 .26
1.45
1.51
1 .36
0.99
0.42
0.44
0,31
0.33
0.33
0.29
0.28
0.28
0.27
0.24
0.26
0.24
NH3 N02N03
IMG/L)
0.08
0.05
0.05
0.04
0.05
0.08
1.10
1.19
1.29
1.07
0.58
0.06
0.09
0,04
J.08
0.06
0.05
0.06
0.07
0.08
0.06
0.04
0.04
0.20
0.14
0.11
0.17
0.20
0.56
0.71
0.77
o.ei
0.87
0.95
O.fcb
0.87
0.72
0.79
0.69
0.47
0.44
0.41
0.24
0.16
0.09
0.04
TP04
0.20
0.19
0.18
0.19
0.20
0.24
0.51
0.47
****
0.40
0.36
0.41
0.32
0,38
0.37
0.40
0.42
0.38
0.43
0.46
0.45
0.57
0.4B
TP04F
(MG/L
****
0.08
0.07
0.06
0.08
0.12
0.33
0.28
0.28
0.24
0.19
0.14
0.14
0.14
0.14
0.15
0.16
0.20
0.26
0.32
0.34
0.41
0.36
PI
>
0.04
0.04
0.04
0.04
0.04
0.07
0.08
0.23
0.24
0.20
0.14
0.10
0.10
0.10
0.10
0.11
0.12
0.14
0.23
0.30
0.31
0.34
0.33
CHLORO
(UG/L)
31.5
54.0
22.5
16.5
25.5
22.5
42.0
43.5
61.5
42.0
61.5
100.5
91.5
106.5
46.0
78.0
78.0
61.5
30.0
31.5
25.5
25.5
42.0
BOD5 BDD20
(HG/U)
****
****
****
****
****
****
****
4.2
****
****
4.9
****
3.4
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2.8
****
3.2
****
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2.4
****
****
3,0
****
****
«***
****
****
****
****
11.3
****
****
9.7
****
7.8
****
6.6
«*«*
7.7
****
****
4.0
****
»***
6.0
DO 00(5)
(MG/L)
7. be
10.31
11. 3b
9.60
9.52
7.84
7.06
7.71
7.06
7.30
8.14
10.24
9.50
9.75
a. 12
7.88
8.80
9.04
8.89
5.95
6,27
7.91
6.10
*****
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**«* «*** «***
**** **** «***
**** **** ****
**** *«** ****
**** **** ****
**«* **** ****
**** **** «***
WO Zt'O ZE'O
WO It'O ȣ'0
90'0 EI'O K'O
90'0 SI'O iE'O
VI'O IZ'O Z*'0
at'o z*o z*«o
ZZ'O flZ'O 65'0
61'0 *Z'0 OS'O
*0'0 Ot'O VZ'O
*0'0 II'O ZZ'O
WO iO'O 81'0
WO 60'0 AI'O
WO 60'0 81'0
WO BO'O 80'0
*0'0 60*0 OZ'O
(1/9W)
**** «***
**** ****
«*** *«**
**** ****
**** ****
**** ***«
**** **«*
**** ***«
<5i'0 WO
?t*0 WO
00*1 6fC
06'0 99'0
*t*0 Eft
99'0 EI'I
Z9*0 */.*!
SS'O 6£*T
^E*0 VO'O
95*0 WO
6£*0 »0*0
iz*o *»o*o
OZ'O »0*0
tl'O *0*0
<51'0 *0'0
«*** ****
**** ****
**** «*«*
**** ****
***« **«*
**** ««**
***« ****
**** ****
83*0 9*'0
»?*0 9b*0
ZS*0 ti'O
16*0 EZ'I
6E* I Z9' T
EE' I ES'I
E6M SZ'Z
ZS'I *i'I
03*0 IZ'O
OZ*0 EZ'O
OZ'O OZ'O
oz'o oz*o
OZ'O OZ'O
OZ'O VZ*0
EZ'O 9£'0
**** *****
**** *****
**** *****
**** *****
**** *****
**** *****
**** *****
**** *****
90'Z &">**
£
Z
vt
I
Vd
8d
(I/OH)
is>no no
(1/3H)
ozooa 9009
id
(1/OW)
EONZON EHN
(T/3H)
N>I
(1/9H)
ooi
(Idd)
NI1VS
Hd
(NI)
IHD03S aani
*****************************«**#***************************
BAST 'OE isnanv aoj viva »3Aia ovwoiod
************************«**«**#******************«**********
-------
****************** ****«************«**#«*******«**********£*
POTOMAC KIVER DATA FOR SEPTEMBER 5, 1978
*«********«****««**««**««** **«**«««««*****:»**««*«*«*«*******
STA.
P8
P4
1
1A
2
3
4
5
5A
6
7
8
£A
9
10
10B
11
12
13
14
15
15A
16
RK1
0.0
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
18.4
22.3
24.3
26.9
30.6
34.0
36.0
42.5
45.8
52.4
58.6
62.8
67.4
TEMP
(C)
****
25.5
25.7
26.0
25.8
26.3
26.3
26.3
26.7
26.8
26.8
26.6
26.7
26.9
26.7
26.5
26.9
****
*«**
**«*
****
«***
****
TURB
10.0
4.5
3.8
3.8
5.3
6.5
5.5
4.5
3.3
3.1
5.5
7.5
9.9
9.5
9.5
10.0
9.9
*«**
****
****
****
**«*
****
SECCHI
(IN)
****
24.0
24.0
23.0
18.0
22.0
23.0
23.0
24.0
26.0
23.0
17.0
18.0
18.0
19.0
17.0
22.0
**«*
«***
*««*
****
****
****
PH
*««»
«***
«**«
<**«
«*«*
****
***«
«***
****
««**
**«*
«*««
****
****
*«**
****
*««*
**«*
****
««**
****
*««*
*«**
SAL IN CUND TOC TOCF TKN TKNF
(PPT) (MG/L) (MG/L)
***** ***** 5.67 1.24 0.87 0.87
***** 0.44 2.12 1.00 0.24 0.21
***** 0.45 2.03 1.00 0.22 0.22
***** 0.45 5.92 1.00 0.37 0.22
***** 0.45 3.76 1.00 0.43 0.24
***** 0.31 4.32 1.00 0.91 0.64
***** 0.39 3.63 1.00 0.44 0.37
***** 0.39 4.13 1.00 0.78 0.78
***** 0.30 4.75 1.00 0.81 0.81
***** 0.30 4.02 1.00 0.88 0.74
***** 0.32 4.50 1,00 0.72 0.64
***** 0.22 5.36 1.00 0.53 0.41
***** 0.35 3.63 *«** 0.47 0.39
***** 0.32 5.92 1.00 0.50 0.37
***** 0.30 4.10 1.00 0.44 0.37
***** 0.20 4.47 1.00 0.33 0.33
0.80 ***** 3.63 1.00 0.28 0.28
***** ***** ***** ««*« **** ****
***** ***** ***** ««** ***« ***«
***** ***** ***** #«*« **#* ****
***** ***** ***** **** **** ****
***** ***** ***** **«* **** ****
***** ***** ***** «««* **** *«?*
NH3 NU2N03
(MG/L)
0.87
0.04
0.87
0.04
0.04
0.64
0.27
0.78
0.81
0.71
0.48
0.04
0.04
0.04
0.04
0.04
0.04
****
****
««»*
«**«
****
****
0.91
0.87
0.85
0.85
0.87
0.45
0.45
0.48
0.57
0.68
0.94
1.37
1.17
1.20
0.95
0.60
0.53
**«*
*«««
«««*
**«*
****
**«*
TP04
0.25
0.24
0.24
0.21
0.25
0.44
0.32
0.36
0.51
0.35
0.32
0.40
0.41
0.41
0.43
0.49
0.45
««**
****
«**«
****
****
*«**
TP04F PI
(MG/L)
0.10
0.14
0.16
0.14
0.13
0.18
0.12
0.18
0.17
0.17
0.16
0.13
0.10
0.13
0.15
0.41
0.20
*««*
*«**
**«*
*«*»
««**
«*«*
0.04
0.07
0.07
0.06
0,06
0.12
0.06
0.11
0.10
0.10
0.08
U.06
0.06
O.C6
0.09
0.15
0.15
****
***«
«***
«**«
«**«
«**«
CHLORO
(UG/L)
42.0
10.5
6.0
12.0
10.5
28.5
12.0
27.0
21.0
16.5
30.0
52.5
49.5
28.5
7.5
22.5
62.2
*****
*****
*****
*****
*****
*****
B005 B0020
(MG/L)
4.7
1.3
1.7
1.5
1.9
4.2
3.2
4.1
6.3
6.9
7.1
5.3
4.7
5.1
3.7
4.6
3.2
****
««**
«***
****
«*«*
****
****
****
*#**
*«*«
*«**
«***
«***
*«**
****
****
«***
*««*
****
««**
****
*««*
«*««
****
****
****
****
«**«
****
DO 00(5)
(MG/L)
B.05 *****
8,29 *****
8.49 *****
8.65 *****
8.33 *****
8.04 *****
7.72 *****
6.08 «««*«
5.96 *****
5.96 *****
6.41 4****
6.52 *****
7.81 *****
7.30 *****
7.30 *****
7.70 *****
7.2B *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
-------
$«*$$*$$**«*************************************************
POTOMAC RIVER DATA FOR SEPTEMBER 11, 1978
«*«*****«****«**«*«***********««****«******«**««**«***«**#**
STA.
P8
P4
1
1A
2
3
4
5
00 5A
00
6
7
8
8A
9
10
10B
11
12
13
14
15
15A
16
KHI
0.0
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
18.4
22.3
24.3
26.9
30.6
34.0
3fa.O
42.5
45.6
52.4
58.6
62.6
67.4
TEMP
(C)
26.0
27.5
27.0
27.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
26.0
27.0
26.0
26.0
26.0
26.0
26.0
TURB
8.5
5.3
6.5
6.0
5.6
10.0
6.5
9.5
8.5
6.5
7.5
8.0
10.0
10.0
10.0
12.0
11.0
9.5
7.0
6.0
9.0
5.5
6.0
SECCHJ
(IN)
4***
21.0
26.0
28.0
21.0
20.0
21.0
22.0
23.0
28.0
32.0
26.0
22.0
18.0
22.0
20.0
20.0
24.0
34.0
35.0
30.0
42.0
52.0
PH
****
8.6
8.6
8.3
6.9
8.3
7.8
7.8
7.6
7.8
7.7
7.5
8.3
8.8
8.0
8.4
8.4
8.1
8.3
7.9
7.8
7.6
7.5
SALIN
(PPT)
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
««««*
*****
*****
CONO
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
TOC TOCF
CMG/L)
5.93
5.91
4.07
4.17
4.98
4.37
5.41
5.16
4.72
4.67
3.82
8.34
5.16
4.76
4.72
4.57
5.36
4.42
5.23
4.47
6.35
4.83
4.86
1.00
1.20
1.00
1.18
1 .00
1.20
1.00
1.26
1 .06
1.00
2.29
6,10
2.09
1.26
1.36
1.06
1.11
1.11
1.53
1.16
1.94
1.00
1.75
TKN TKNF
(MG/L)
0.54 0.53
0.30 0.25
0.31 0.26
0.28 0.23
0.26 0.26
0.46 0.42
1.78 1.74
1.52 1.49
1.36 1 .36
0.92 0.82
0.64 0.64
0.63 0.52
0.63 0.43
0.76 0.43
0.68 0.54
0.65 0.40
0.49 0.41
0.45 0.38
0.45 0.34
0.31 0.24
0.34 0.31
0.28 0.2U
0.31 0.30
NH3 N02NU3
(MG/L)
0.08
0.04
0.04
0.06
0.05
0.14
1.39
1.07
0.93
0.35
0.11
0.06
0.05
0.04
0.08
0.07
0.06
0.07
0.05
0.05
O.Ob
0.05
0.07
0.42
0.26
0.26
0.24
0.21
0.41
0.63
0.74
0.84
1.04
1.08
0.95
0.83
0.59
0.87
0.59
0.43
0.37
0.23
0.14
0.10
0.04
0.04
7P04
0.27
0.19
0.19
0.19
0.20
0.25
0.50
0.42
0.41
0.34
0.32
0.35
0.38
0.42
0.45
0.50
0.50
0.40
0.46
0.44
0.57
0.48
0.45
TP04F
(MG/L
0.12
0.08
0.08
0.07
0.07
0.08
0.23
0.20
0.21
0.18
0.15
0.13
0.14
0.13
0.17
0.23
0.24
0.23
0.30
0.31
0.37
0.38
0.38
PI
}
0.06
0.04
0.04
O.C4
0.04
0.04
0.18
0.36
0.18
0.14
0.10
o.oe
0.09
0.08
0.14
0.20
0.21
0.21
0.28
0.31
0.36
0.37
U.38
CHLORO
(UG/L)
24.0
18.0
21.0
16.5
49.5
51.0
60.0
57.0
45.0
55.5
66.0
100.5
110.0
88.5
94.5
63.0
63.0
48.0
36.0
25.5
90.0
49.5
43.5
BOOS B0020
(MG/L)
****
****
**«*
**«*
****
«***
****
6.4
****
****
4.4
****
4.4
««*«
3.9
«***
3.6
**««
****
2.0
****
***«
3.5
****
****
*«**
****
***«
**«*
*«*«
12.8
****
****
7.9
****
10.2
****
9.2
****
8.2
***«
****
4.5
*«*«
****
5.0
00 OOJ5J
(MG/L J
8.17
9.82
9.94
7.95
8.28
8.15
7.02
7.01
5.76
6.40
6.3V
7.91
8.30
9.89
6.93
7.59
7.45
7.20
8.28
6.97
6.54
5.73
5.24
*****
8.48
10.13
8.15
7.70
8.02
6.77
6. US
5.30
6.66
5.89
7.62
8.07
9.4b
7.24
7.57
7.78
7.25
7.75
6.73
6.51
5.94
5.27
-------
******X:*********** ***********«*******:»*********************«
POTOMAC KIVtR DATA FOR SEPTEMBER 13, 1978
«***«$$$****<:$***********************************«**********
STA.
P8
P4
1
1A
2
3
4
5
CO 5A
vo
6
7
8
8A
9
10
10B
11
12
13
14
15
15A
16
RHI
0.0
1.9
3.4
4.9
5.9
7.6
1C.C
12.1
13.6
15.2
1*.4
22.3
24.3
26.9
30.6
34.0
3fc.O
42.5
45.8
52.4
58.6
62.8
67.4
TEMP
(0
25.0
25.7
25.9
25.4
25.6
25.1
25.3
25.6
25.5
25.5
25.3
25.7
25.8
25.7
25.9
25.7
25.8
26.1
26.1
26.0
25.9
25.9
25.9
TURB
14.0
11.0
11.0
10.0
11.0
19.0
12.5
15.0
14.0
10.5
9.5
9.2
20.0
11.0
11.5
17.0
16.5
10.0
6.5
13.0
12.5
8.4
4.7
SECCHI
(IN)
««*«
18.0
21.0
26.0
24.0
19.0
23.0
22.0
23.0
22.0
25.0
24.0
20.0
25.0
24.0
15.0
18.0
22.0
24.0
23.0
24.0
32.0
56.0
PH
*«*«
8.2
8.2
8.1
8.1
8.1
7.8
7.7
7.8
7.6
7.6
7.6
7.6
7.9
8.2
8.3
8.3
8.3
8.1
8.0
«**
7.7
7.7
SAL IN COND
(PPT)
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
***** *****
0.23 0.47
0.21 0.49
0.22 0.51
0.21 0.45
0.14 0.42
0.20 0.42
0.20 0.41
0.84 1.62
2.26 4.10
4.04 7.15
5.57 9.65
6.83 11.79
TOC 10CF
( P.G/L )
6.95
4.94
5.19
5.76
5.86
5.24
5.55
5.76
6.42
6.01
5.04
4.37
5.32
5.62
6.64
8.00
4.42
5.70
6.06
5.09
6.24
5.27
4.73
3.55
4.66
3.04
2.12
4.30
3.52
2.99
3.86
4.88
4.61
2.87
3.50
3.55
3.19
3.04
3.99
3.45
3.76
4.51
4.03
4.99
2.94
3,04
TKN TKNF
(MG/L)
0.46 0.46
0.40 0.37
0.39 0.33
0.41 0.37
0.42 0.38
0.38 0.38
1.22 1.18
1.60 1.60
1.78 1.60
2.05 2.05
1.27 1.24
0.72 0.64
0.66 0.53
0.66 0.53
0.71 0.49
0.71 0.49
0.63 0.43
0.56 0.41
0.59 0.47
0.50 0.47
0.48 0.48
0.43 0.38
0.43 0.39
NH3 NU2N03
(MG/L)
0.08
0.07
0.08
0.08
0.08
0.08
U.77
0.54
1.16
1.52
0.63
0.10
0.07
0.07
0.06
0.07
0.07
0.07
0.07
0.07
0.07
0.06
0.07
0.40
0.39
0.41
0.41
0.36
0.26
0.37
0.41
C.46
0.64
1.07
1.23
1.09
1.02
0.79
0.7t>
0.6b
0.42
0.30
0.17
0.13
0.07
0.04
TP04
0.28
0.26
0.25
0.25
0.26
0.26
0.40
0.53
0.49
0.51
0.42
0.38
0.54
0.43
'0.43
0.53
0.55
0.46
0.44 .
0.51
0.48
0.49
0.42
TP04F PI
(MG/L)
0.13
0.10
0.11
0.11
0.11
0.09
0.19
0.24
0.22
0.24
0.20
0.17
0.17
0.16
0.16
0.18
0.23
0.24
0.26
0.33
0.34
0.36
0.36
0.05
0.04
O.C4
0.04
0.04
0.04
0.12
0.19
0.16
0.18
0.14
0.11
0.10
0.09
0.09
0.12
0.18
0.20
0.22
0.31
0.34
0.35
0.36
CHLORO
(UG/L)
39.0
34.5
33.0
27.0
34.5
30.0
36.0
42.0
45.0
51.8
54.0
64.5
99.0
90.0
43.5
57.0
75.0
103.5
132.0
115.5
24.0
24.0
45,0
B005 80020
(MG/L)
2.7
2.7
2.0
2.5
2.4
2.3
4.2
5.3
5.2
7.0
7.6
4.7
***«
5.0
4.9
4.5
4.6
4.3
2.2
1.6
1.6
2.1
1.8
«*«*
****
****
****
****
****
****
****
****
****
**«*
*«**
****
****
****
****
****
****
****
****
«***
*«**
****
UO 00(5)
(MG/L)
a. 11
7.35
7.43
7.20
7.25
7.63
6.72
5.74
6.86
5.86
5.51
6.07
6.05
7.10
8.14
7.54
7.54
7.69
7.65
7.01
6.60
6.42
6.14
*****
6.'J5
6.75
8.00
7.69
5.99
5.44
6.58
5.17
5.01
6.72
6.19
6.-J3
7. 58
8.28
6.86
7.60
6.84
7.89
7.16
5.59
6.75
6.46
-------
««4*«#«««*«*«$***«««4«44444**444*4«4444**444*4*4444«*4*«*44*
POTOMAC MVER DATA FOR SEPTEMBER 25, 1978
44444444444*44444444444444*444444*4444444444444444444*444444
STA.
P8
P4
1
1A
2
3
4
5
5A
6
7
8
8A
9
10
10B
11
12
13
14
15
15A
16
RMI
0.0
1.9
3.4
4.9
5.9
7.6
1C.O
12.1
13.6
15.2
18.4
22.3
24.3
26.9
30.6
34.0
38.0
42.5
45.8
52.4
58.6
62.8
67.4
TEMP
(C)
4444
23.5
23.0
23.5
24.0
24.0
23.5
24.0
23.5
23.0
23.5
4444
4444
4444
24.0
23.4
23.6
23.4
23.3
23.3
23.8
23.4
24.1
TURB
4444
4444
4444
4444
4444
4**4
44*4
4444
444*
444*
4444
4444
4444
4444
444*
44*4
444*
4444
4444
4444
4444
»***
4444
SECCH1
(IN)
4444
4444
24.0
30.0
24.0
24.0
24.0
28.0
26.0
26.0
22.0
24.0
25.0
22.0
22.0
20.0
21.0
24.0
23.0
22.0
26.0
34.0
36.0
PH
4444
8.0
8.0
7.9
7.9
7.8
7.3
7.5
7.3
7.2
7.5
8.0
8.2
8.5
8.6
8.5
8.3
8.1
7.9
7.7
7.5
7.5
7.1
SAL IN
(PPT)
44444
44*44
4444*
«*444
44444
44444
44444
44444
44444
44444
44444
44444
44444
44444
0.40
0.40
0.45
1.10
1.35
2.46
4.50
6.22
7.40
CONO
44444
44444
44444
44444
4444*
44*44
44*44
44444
4444*
44*4*
44444
44444
44*4*
44444
0.85
0.84
0.94
2.00
2.37
4.30
7.55
10.30
12.30
TOC TOO
(MG/L)
3.55 2.42
4.57 2.26
3.46 2.42
4.21 2.42
4.13 2.42
4.99 2.42
5.05 3.98
6.12 3.71
7.64 3.87
5.91 6.44
6.60 5.10
6.04 3.33
6.5C 3.65
8.64 3.87
8.86 3.65
6.98 3.71
7.68 4.19
5.53 3.87
5,16 3.71
8.48 3.87
4.24 3.92
3.96 3.87
12.40 2.85
TKN TKNF
(MG/L)
0.67 0.60
0.57 0.55
0.57 0.52
0.55 0.51
0.57 0.52
0.75 0.56
2.33 1.71
1.82 1.26
1.71 1.21
1.23 0.89
1.10 0.87
1.07 0.83
0.95 0.83
0.80 0.64
0.75 0.56
0.75 0.56
0.81 0.64
0.75 0.67
0.72 0.63
0.77 0.64
0.80 0.66
0.75 0.64
0.72 0.69
NH3 NQ2N03
(MG/L)
0.04
0.04
0.04
0.06
0.09
0.20
1.60
1.05
0.74
0.23
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.05
0.08
0.04
0.04
0.07
0.69
0.63
0.59
0.54
0.54
0.49
0.61
0.81
1.61
1.89
1.71
1.38
1.04
0.63
0.63
0.41
0.39
0.30
0.28
0.15.
0.18
0.17
0.14
TP04 TP04F PI CHLORO
(MG/L) (UG/L)
0.22
0.20
0.20
0.20
0.20
0.23
0.64
0.47
0.41
0.34
0.32
0.31
0.36
0.41
0.41
0.48
0.46
0.39
0.40
0.45
0.43
0.42
0.39
0.16
0.14
0.14
0.12
0.12
0.13
0.43
0.29
0.22
0. 19
0.15
0.14
0.15
0.16
0.18
0.22
0.23
0.24
0.27
0.29
0.31
0.31
0.30
O.C9
O.C6
0.06
0.06
0.05
0.06
0.41
0.26
0.1E
0.13
0.07
0.06
0.08
0.08
0.10
0.15
0.19
0.22
0.23
0.2B
0.31
0.31
0.30
21.0
21.0
25.5
25.5
18.0
42.0
39.0
54.0
76.5
72.0
79.5
103.5
111.0
126.0
133.5
141.0
93.0
63.0
52.5
30.0
25.5
16.5
9.0
B005 B0020
(MG/L)
4444
4444
4444
4444
4444
4444
444*
7.9
****
4444
6.2
4444
7.1
4444
7.6
4444
5.7
444*
444*
2.0
«444
4444
1.4
4444
4444
4444
«444
4*44
4444
4444
12.0
44*4
4444
8.4
4*44
10.5
4444
11.0
4444
11 .2
44*4
44*4
4.5
4444
*444
2.9
00 00(5)
(MG/L)
8.99
9.52
9.43
8.51
7.70
7.75
5.70
6.78
6.11
5.90
7. OB
9.22
9.18
10.33
10.28
9.20
8.78
8.15
7.81
7.25
6.43
5.84
5.13
444*4
9.48
9.1(5
8.46
7.86
7.38
5.59
6.15
5.84
3.42
7.43
7.95
8.1 7
9.04
9.88
fa. 55
8.50
8.13
7.74
6.93
6.52
5.76
5.09
-------
««#«*«********$*«*«**«**«*«*# ****««****«**********«**«****«$
POTOMAC RIVER DATA FOR SEPTEMBER 27, 1978
g^^tt^^g*^**:* ««*«*«««**#***««*********««$***********«#*
STA.
P8
P4
1
1A
Z
3
4
5
5A
6
7
8
8A
9
10
JOB
11
12
13
It
15
15A
16
KM I
0.0
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
18.4
22.3
24.3
26.9
30.6
34. C
38.0
42.5
45.6
52.4
58.6
62.8
67.4
TEMP
(C)
21.0
****
«***
****
****
23.1
24.3
24.0
23.4
23.4
23.5
23.3
23.6
22.6
22.5
22. 6
22.7
22.4
22.6
20.7
22.5
22.1
22. b
TURB
9.8
****
****
****
****
12.0
9.5
14.5
9.6
8.1
8.0
7.2
8.6
9.8
8.0
10.5
9.7
8.0
8.4
14.0
6.2
7.7
4.0
SECCHI
(IN)
****
****
****
****
****
18.5
21.0
16.0
19.0
23.0
20.5
19.0
****
14.5
17.5
16.0
17.0
18.0
23.0
19.0
27.0
26.0
40.5
PH
****
*«**
****
#***
****
****
****
****
****
****
«***
****
****
****
****
****
****
*«*«
****
«***
****
.«***
****
SAL IN
(PPT)
*****
*****
*****
*****
*****
0.28
0.25
0.30
0.30
0.32
0.25
0.23
0.15
0.26
0.14
0.20
0.21
0.92
1.55
3.54
4.78
6.50
7.33
CDND
*****
*****
*****
*****
*****
0.67
0.66
0.64
0.60
0.65
0.60
0.59
0.42
0.48
0.36
0.38
0.47
1.60
2.62
5,85
7.85
10.60
11.88
TOC TGCF TKN TKNF
(MG/L) (MG/L)
8.17 1.00 0.62 0.55
***** ***« **** *«**
***** **** **** ****
***** «««* **** ****
***** **** **** ****
5.02 1.27 0.92 0.83
6.31 1.45 2.08 1.66
10.79 1.34 1.55 1.55
7.91 2.91 1.12 1.12
7.27 3.07 1.00 0.98
6.68 1.94 0.92 0.92
9.03 1.34 0.74 0.69
7.82 1.88 0.76 0.76
12.32 1.40 0.78 0.55
9.16 1.02 0.48 0.45
7.77 2.05 0.48 0.45
8.52 3.29 0.48 0.44
7.4U 1.94 0.38 0.37
6.31 1.99 0.38 0.35
5.56 1.13 0.48 0.42
5.77 3,07 0.55 0.55
3.80 1,68 0.48 0.42
6.09 1-27 0.36 0.34
NH3 NU2N03
(MG/L)
0.04
****
**«*
**«*
****
0.33
1.44
0.86
0.41
0.15
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.58
****
**«*
**«*
**«*
0.61
0.75
1.40
1.78
1.90
1.69
1.26
0.94
0.59
0.59
0.32
0.31
0.25
0.20
0.20
0.17
0.17
0.15
TP04
0.21
****
****
*«**
****
0.28
0.54
0. 55
0.42
0.42
0.31
0.29
0.39
0.39
0.39
0.43
0.44
0.40
0.33
0.45
0.40
0.36
0.33
TPD4F
(MG/L
***«
****
**««
****
****
0.13
0.29
0.23
0.17
0.15
0.11
0.10
0.10
0.11
0.13
0.17
0.20
0.17
0.10
****
***«
«*««
****
PI
)
0.04
****
****
***«
***#
0.07
0.29
0.20
0.13
0.11
0.06
0.05
0.06
0.07
0.09
0.14
0.17
0.17
0.10
0.26
0.27
0.30
0.31
CHLORO
(UG/L)
27.0
*****
*****
*****
*****
39.0
31.5
64.5
84.0
78.8
73.5
87.0
117.0
129.0
136.5
159.0
139.5
75.0
57.0
28.5
25.5
16.5
12.0
B005 BO 020
(MG/L)
1.9
****
***#
*«**
****
3.7
5.3
8.7
3.5
7.9
5.0
4.0
4.4
5.0
4.1
3.7
3.6
2.2
1.9
1.2
1.4
0.7
1.5
****
****
****
«***
****
****
«**«
**«*
***«
****
****
«***
****
***«
«*«*
«*«*
****
****
»***
****
****
****
«««*
00 DU(5)
(MG/L)
9.13
*****
*****
*****
*****
6.55
6.63
5.B9
5,85
6. 80
a.vs
8.99
11.26
12.59
10.06
10.79
9.30
8. 90
7.07
6.16
6.06
5.34
4.67
*****
*****
*****
*****
*****
6.87
6.63
6.04
3.90
5.24
a. 86
9.30
8.90
11.21
10.05
a. 60
7.68
7.90
7.13
5.9/
6.21
5.46
4.79
-------
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EPA Form 2220-1 (9-73) (Revert*)
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
PA 903/9-80-002
3. RECIPIENT'S ACCESSION NO.
TITLE AND SUBTITLE
Assessment of 1978 Water Quality Conditions in
the Upper Potomac Estuary
5. REPORT DATE
March 1980
6. PERFORMING ORGANIZATION CODE
AUTHORIS)
Leo 0< clarkj Stephen E. Roesch, and
Molly M. Bray
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM CLEMENT NO.
B203/B303
PERFORMING ORGANIZATION NAME AND ADDRESS
Annapolis Field Office, Region III
U.S. Environmental Protection Agency
Annapolis Science Center
Annapolis, Maryland 21401
11. CONTRACT/GRANT NO.
N/A
2. SPONSORING AGENCY NAME AND ADDRESS
Same
13. TYPE OF REPORT AND PERIOD COVERED
In House; Final
14. SPONSORING AGENCY CODE
EPA/903/00
5. SUPPLEMENTARY NOTES
6. ABSTRACT
The second successive intensive monitoring program in the Potomac Estuary was
performed by the Annapolis Field Office, U.S. E.P.A., during the period of July
to September, 1978. This program consisted of three distinct elements: (1) slack
tide sampling over a sixty-five mile reach of the upper estuary; (2) sampling of
the effluents at the eight major wastewater treatment plants in the Washington
Metropolitan Area and (3) special field and laboratory studies which addressed
specific aspects of the dissolved oxygen budget for mathematical modelling purposes
as well as the chronic problem of eutrophication. . The relevant findings and
conclusions that were generated as a result of this data (including appropriate
comparisons with the previous year) along with a tabulation of the raw data are
presented in this report.
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COSATI Field/Group
Sediment Oxygen Demand
Diurnal (A) DO
First Order Reaction
Biochemical Oxygen Demand
Algal Elemental Composition
Potomac Estuary
High/Low Slack Water
Rate Limiting Nutrient
N to P Atomic Ratios
Drouge Study
Pseudanabaena Catenota
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EPA Form 2220-1 (9-73)
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