IH
ANNAPOLiS FIELD OFFICE
SITUATION REPORT
POTOMAC RIVER
WORKING FOR A BETTER ENVIRONMENT
: ENVIHONMENTAL PROTECTION
U.S. EPA ANNAPOLIS FIELD OFFICE, ANNAPOLIS SCIENCE CENTER, Amnpolit, IW. 21401
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9O3R769Q3
SITUATION REPORT
POTOMAC RIVER
May 25, 1976
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I. HISTORY
When Captain John Smith explored the Potomac River in 1608 the waterway
was virtually in a pristine state with abounding fish life. The crude and
limited agricultural activities of the indigenous Indian tribes had little
impact on the aquatic environment. In the late 1790's it was reported
that President Adams swam in the Potomac Estuary near Washington, D.C.
It was about this time that canals were carved along the river and com-
mercial shipping activities took place in the estuary. As the population
in the Washington Metropolitan Area grew, so did water pollution problems
in the Potomac Estuary. The dumping of raw municipal wastes into the
river became so extensive that by the early 1860's President Lincoln fre-
quently was forced to leave the White House at night due to objectionable
sewage odors. Following the Civil War the sewage situation worsened to the
point that President Harrison ordered a system to be devised to convey all
sewage to a point in the river downstream of Washington, D.C.thus collec-
i
tion and transfer of the problem became the first solution to the municipal
waste dilemma. It was not until 1938 that sewage treatment measures were
employed in the estuary area, and by this time water quality problems had
become quite evident. Even though sewage treatment measures were em-
ployed pervasively, excessive population growth more than offset pollution
abatement efforts. Historically and to this day the primary cause of
water pollution in the Potomac Estuary is municipal waste. Nonpoint
sources of pollution, including agricultural runoff and stormwater loadings,
also contribute significant amounts of pollutants to the Potomac.
II. CURRENT STATUS
The current problem facing the Potomac River and Estuary is an inter-
related one consisting of a marginally sufficient water supply, variable
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water quality in the upper reaches of the estuary due to advanced
eutrophication (over fertilization of nutrients), and problems of as yet
undetermined magnitude as regards toxic metals and organohalogens and
their effects on living organisms in the Potomac.
The Washington Metropolitan Area is a rapidly growing region with
about 2.8 million people. Present municipal water use is 370 mgd with
72 percent (265 mgd) supplied from the Potomac River above Washington
(Great Falls). Projected population and water supply needs are shown
in Table I. Present resources are insufficient to supply peak needs
during sustained low flows. (See Table II.) It is very possible that
a drought could recur as in 1966 and 1969 where the metropolitan water
supply would be seriously depleted, if not inadequate to meet water
supply needs since the maximum demand of record has exceeded the
minimum flow, though fortunately not at the same time. The concurrence
of these adverse conditions is not hypothetical and a number of alter-
natives are being considered to alleviate this situation. The U.S.
Army Corps of Engineers has proposed three alternative impoundment
systems for water supply augmentation. (See Table III.) Use of the
freshwater portion of the estuary for emergency water supply during
sustained low flow periods would meet any immediate crisis since the
lead time for construction of impoundments is approximately 10 years
after approval.
The water supply situation has been further complicated by the
Montgomery County decision to construct a municipal sewage treatment
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TABLE'I
Water Supply Needs
Year
1969
.1980
2000
2020
Population
2,700,000
k, 000, 000
6,700,000
9,300,000
Yearly avg.
(mgd)
370
570
1010
1570
Maximum Month
(mgd)
.1*7°
. 720
1310
20l;0
Maximum Daily
(mgd)
660
1000
1820 ,
2820
TABLE II
Low-Flow Characteristics Before
Water Supply Diversion
Withdrawal from the Potomac Estuary
or from Direct Reuse*-
Recurrence.
Interval
(years)
20
50
Minimum Monthly
Fresh Inflow
(mgd)
1300
1170
910
1900
For a 720
mgd Need
(mgd).
none
none
none
2000
For a 1310
mgd "Need
(mgd)
210
2020
For a 20ljO
mgd Need
(mgd)
600
1070
1330
Withdrawal based on minimum 30-day low flow concurrently with a
maximum 30-day water supply withdrawal and a 200 mgd minimum base
flow over Great Falls into the estuary
TABLE III
Bloomington
Bloomington, Verona, and Sixes Bridge
Bloomington, Verona, Sixes Bridge, Town Creek,
North Mountain, Sideling Hill, and Little
Cacapon
System
I
II
III
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plant discharging to the Potomac River above the metropolitan water
intakes at Great Falls. Various alternatives pertaining to this
*
plant are still undecided, namely siting, plant design/capacity and
degree of treatment required and most important its effects on the
water supply of Metropolitan Washington.
The wastewater disposal problem in the upper reach of the
estuary from Great Falls to Indian Head, Maryland, results from the
discharge of 325 mgd of municipal sewage from 18 facilities, of which
the Blue Plains plant of the District of Columbia is the largest
(Fig. I). Of the 325 mgd, 45.5, 23.1, and 35.4 percent, respectively,.
come from Maryland, Virginia, and the District of Columbia. Since
1913 wastewater volumes have increased eightfold, from 42 to 325 mgd.
Similar trends have occurred for total nitrogen and phosphorus with
10-fold and 24-fold increases, respectively. Table IV shows waste-
water loading trends of the Washington Metropolitan Area. Increased
wastewater loadings to the upper Potomac Estuary have resulted in
increased amounts of nutrients and consequently the wore frequent
occurrence of nassive, -undesirable algal blooms.
Under summer and fall conditions large populations of blue-green
algae (pollution tolerant), mainly Anacystis sp., are predominant in
the freshwater portion of the estuary. These algae are not grazed by
higher trophic forms and are therefore useless in the food chain.
When excessive mats of these blooms expend their life cycle and decay,
dissolved oxygen in the v/ater is reduced below acceptable levels to
sustain fish life.
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POTOMAC RIVER ESTUARY
\YASTEWATER TREATMENT PLANTS
ANNAPOLIS FICLD OFFICE EPA
;97I
N
\
WASHINGTON D.C.
PENTAGON Q
(I.Omgd.) '
RIVER MILES FROM CHAIN SR'DGE-'0
ARLINGTON
I40mgd.)
WootJrow Wilson
Memoriol
ZONE
VIRGINIA
ALEXANDRIA SSS
(Si mgd.)
V.'ESTGATE
LITTLE HUNTING Cr.JZI
'V
DOGUE Cr. y^L. A-'
FORT BELVOiR
LOV.'ER POTOMAC
(SGroodl.)
PISCATAWAY Cr.
(90 rr.
^/DISTRICT OF COLUMBIA
(3O9mgd.)
RIVER MILES FROM CHAIN BRIDGE = 15
BROAD CREEK
ANDREWS
A.F.B.
ZONE
MARYLAND
RIVER MILES FROM CHAIN BSiOGf. = 3Or
EXISTING WASTEV.'ATER TREATMEN'T PLANTS
(PROJECTED FULL DEVELOPMENT CAPACITY)
D EXISTING'PLANTS TO EC ABANDONED
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TABLE IV
WASTEWTER LOADING TR3IES
VASHE&TOtf MUTKOPOLITA:? AREA
Year
1913
1932
1544
1954
1957
19&0
196;
1063
1969
17/0
Population
_ S?rvod
320,000
575,000
1,149,000
1,350,000
l,6eO;000
1,360,000
2,100,000
2,415,000
2,450,000
2,535,000
Flovfl
"toed) .
42
75
167
195
210
222
265
31?
320
322
Untreated
' 5-Pr,y_DOD
(Ibo/day)
58,000
103,000
235,000
280,000
305,000
370,000.
417,000
4245,000
439,000
484,000
Rejnovnl
5-Ctvy BOD
*
0
0
40
28
33
70
70
70
71
1-
71
Treated
5-Dnv y30D
(Ibo/day)
58,000 .
103,000
141,000
200,000
204,000
110,000
125,000
130,000
129,000
141,000
Ultisatefa
Car, 7JOD
(Iba/doy;
84,000
149,000
205,000
290,000
297,000
160,000
182,000
188,000
185,000
aC4,000
Ultimate f 4
NU. POD
.(ibb/cfcy)
29,000
52,000
105,000
145,000
153,000
170,000
192,000
226,000
222,000
254,000
Total1
Ultimate 300
( r\nr* + >Mt \
ll T 111 ' * " * L
(Ibo/doy)
n3,oco
201,000
310, 000
435,000
450,000
330,000 . .
;S4,CCO
, 414,000
408,000
456,000
Total
ItiliSSTJ!!
(Ita/cU^)
6,400
11,400
23,000
31,700
33,500
37,200
42,000*
50,000
55,000
cO,COO
Total ?io3.
f'??
(Ifej/day)
X,1CO
2,000
4.0CO
5,500
8,600
10,000
ie,3co
20,100
21,100
24, COO
1, Includes estimated sewer overflow loadings
2. Ultirato carboriflccoras EOD « l,/,5 x 5-day SOD -
3. Ultlratc nitrccono'JS BOD " 4.57 x unoxidizcd nitrogen
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In the saline portion of the estuary, growth of marine phyto-
. plankton known as "red tides" proliferates, aggravated by the high
nutrient content in the water. These have teen known to assume forms
toxic to fish life.
The overall effect of increases in nutrient loadings since 1913
(Table IV) on dominant plant forms in the upper estuary has been
continuous and dramatic. Figure II visualizes the successive
domination of various plant forms leading to the present state of
persistent massive summer blooms of the blue-green alga Anacystis
in nuisance concentrations of greater than 50 micrograms per liter
from the metropolitan area downstream as far as Maryland Point. This
condition still persists and will probably increase in intensity
unless the nutrient discharges are significantly reduced.
The major detrimental effects of the wastes being discharged to
the Potomac are:
(1) An abundance of nutrients which causes over-enrichment
of the estuary;
(2) Depletion of dissolved oxygen creating zones of depressed
oxygen levels;
(3) High bacterial densities which preclude use of the river
for any contact recreational activities and as a potable
water supply source.
Approximately 50 million tons of sediment are deposited into the
river each year, with 39 percent of it generated in the Washington
Metropolitan Area. Stringent regulation is needed to
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WASTEWATER NUTRIENT ENRICHMENT TRENDS AND ECOLOGICAL EFFECTS
UPPER POTOMAC TIDAL RIVER SYSTEM
20.000
15.000
«~
O o
10.000-
O
5,000-
O
33
m
NO MAJOR PLANT
NUISANCES
WATER CHESTNUT INVASION
V/ATER
MILFOIL
INVASION
LOCAL
BLUE-GREEN
ALGAL BLOOMS
MASSIVE
PERSISTENT
DUIE-GHEEN
ALGAL BLOOM
NITROGEN
^^~-~
PHOSPHORUS
r250.000
200.000
150.000
to -a
u: >»
< S
u
2
loo.ooo 3
K
o
50.000
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control this obvious pollutant and minimize its harmful potential.
Maryland and the District have specific sediment control ordin-
ances in effect. . :
In the Washington Metropolitan Area, the amount of water used
for manufacturing is insignificant. The major industrial use is
as cooling water.
There are currently six major cooling water users in the
Potomac River tidal system with another being proposed near Sandy
Point. The total cooling water use is 2,71*8 mgd as follows:
Facility .
PEPCO at Benning Rd.
(Washington, B.C.)
PEPCO, Buzzard Point
(Washington, B.C.)
Virginia Heating
(Arlington, Va.)
PEPCO Generating Station
(Alexandria, Va.)
VEPCO, Possum Point
(Quantico, Va.)
PEPCO, Sandy Point
PEPCO, Morgantown
(Charles Co., Md.)
Water
Usage Receiving Water
(mgd J
568
570
ho
Anacostia River
Anacostia River
Remarks
Also Uses
Cooling Towers
Uoo
720
Boundary Channel of
Potomac Estuary
Potomac Estuary
Potomac Estuary
Potomac Estuary
Potomac Estuary
Proposed
Facility
Ultimate Usage
to be llUiO mgd
TOTAL
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Navigational use of the Potomac Estuary waters is primarily
to provide commercial transport via ^-iver barges. Two commercial
firms presently transport various petroleum products from .tank
farms located in the lower Potomac and in the Chesapeake Bay pro-
per to the Washington Metropolitan Area.
Sand and gravel mining is also a water related industrial
use of the estuary bed. Currently, dredging for this purpose is
being conducted in the estuary below Indian Head, Maryland.
* Recreational facilities on or near the Potomac estuary in-
clude a national park, three state parks, seven fish and game
areas of 226 county recreational sites. A study by the Bureau
of Outdoor Recreation indicated that the recreational potential
of the 63? miles of shoreline has barely been developed. Few
public beaches have been opened primarily because of poor water
quality (in the upper reaches) and to some degree the unwelcome
presence of stinging jellyfish. . .
The dockside value of fish, crabs, clams, and oysters taken
. from the Potomac tidal system is about $5 million annually. Sport
fishing contributes more than $0.6 million per year. There are
approximately 95 marina facilities in the tidal Potomac which
accomodate over 5,200 recreational watercraft.
Ill PRESENT ANNAPOLIS FIELD OFFICE EFFORTS .
The Annapolis Field Office currently monitors the Potomac
estuary on a monthly basis. The sampling survey consists of 26
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stations (Fig. Ill) from Point Lookout to Chain Bridge and analyses
are conducted for pertinent chemical and biological parameters re-
lated to the hyper-eutrophic conditions existing in the estuary.
Various intensive surveys have been conducted and documented in the
past few years dealing with specific problems in the Potomac. These
studies provide insight by focusing attention on one aspect of the
pollution problem. .
IV. CURRENT STATUS OF THE CORRECTIVE ACTION PROGRAM
In 1969 the Potomac Metropolitan Area Enforcement Conference,
initiated in 1957 as a means of bringing about cooperative action
among the political jurisdictions, was reconvened. A memorandum of
understanding was agreed upon which established a program for con-
struction of sewage treatment facilities in accordance with the treat-
ment requirements established in an AFO report. Construction is in
progress at the B.C. treatment plant, Virginia treatment facilities
are being upgraded, and Maryland has not as yet selected the sites
for additional treatment plants.
The Interstate Task Force has been set up to implement the program
adopted by the Conference for the metropolitan Washington area.
Upstream problems, with exception of the need to control nutrients
reaching the estuary, are receiving the attention of the specific
states involved.
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/V
OCCOOUA* txr
PO31UM POINT-
LEGEND
© MAJOR WASTE TREATMENT PLANTS
A CAGING STATION - WASHINGTON. DjC.
A DISTRICT OF COLUMBIA
6 ARLINGTON COUNTY i
C ALEXANDRIA SANITATION AUTHORITY
D FAIRFAX COUNTY - WESTGATE PLANT
E FAIRFAX COUNTY - LITTLE HUNTING CREEK PLANT
F FAIRFAX COUNTY - DOGUE CREEK PLANT
G WASHINGTON SUBURBAN SANITARY COMMISSION - PISCATAWAY
H ANDREWS AIR FORCE BASE - PLANTS ONE. FOUR
I FORT BELVOIR -PLANTS ONE. TWO. *
J PENTAGON
K FAIRFAX COUNTY - LOWER POTOMAC PLANT
POTOMAC ESTUARY
Figure III
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