Washington Channel - Watershed Description

Watershed Description – The Washington Channel

Natural Resources Planning: UAP 5414

Matthew Steenhoek

September 24, 2011

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Watershed Description – The Washington Channel

Natural Resources Planning: UAP 5414

Matthew Steenhoek

September 24, 2011

Originally constructed by the U.S. Army Corps of Engineers in the 1880’s, the Washington

Channel is a body of water in Southwest Washington DC which runs between Tidal Basin and the

Anacostia River. The Washington Channel is a unique waterway that has been highly engineered and

was designed to increased maritime travel and commerce while acting as part of a flood control system

for the National Mall and Capital areas of the District. The waters in the Channel, which are fed or

affected by all three of the primary watersheds in the District, the Potomac, the Rock Creek, and the

Anacostia, have been identified as having water quality issues typical of many urban waterbodies and

are classified by the U.S. Environmental Protection Agency (EPA) as “Impaired.” Though there are no

organizations or groups that are solely dedicated to enhancing the overall health of the Washington

Channel, the efforts of DC Water, the Anacostia Watershed Initiative, and various other groups

dedicated to the health of the Potomac, Rock Creek, and Anacostia to help to improve its quality and

health.

HISTORY

A number of natural and environmental hazards came to light in the late 1880’s which led to the

engineered creation of West and East Potomac Parks, the Tidal Basin, and the Washington Channel. The

first was a continued and growing public concern about the public health issues associated with the silty

mud flats known as the Potomac Flats. These flats, which were just south of the White House grounds,

had developed into a collecting ground for sewage that was dumped into the Washington Canal, now

Constitution Avenue. The flats did not fully drain out to the Potomac and were a breeding ground for

disease and feared to be a public health hazard. Secondly, there was a major flood in February of 1881,

caused by snowmelt, which brought the Potomac over its banks and across the National Mall to the

National Botanical Gardens at the base of the Capitol. This major flood event had significant economic

impacts and was enough to cause Congress to act (Robarge, 2011).

Around this same time, there were proposals from T. Albert, of the Army Corps of Engineers, to

dredge parts of the Potomac to help open the river to commerce by providing clear navigable channels

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up to the wharves and docks around 6th St SW. In response to the flooding, Congress directed the Army

Corp of Engineers to dredge the river in accordance with Albert’s proposal. Between 1882 and 1890,

this dredging effort took silt from the area now known as the Washington Channel and created 628

acres of new land on the former site of the Potomac Flats (See Exhibit - 01). These newly-formed lands

became known as East and West Potomac Parks and are now home to the Lincoln and Jefferson

Memorials (Robarge, 2011). The operation was overseen by Major Hains, who replaced Albert in 1882,

and for whom the southernmost tip of East Potomac Park was named (Hains Point) in 1917 (US Army

Corps of Engineers, 2002).

In order to help with flood control and to keep the Washington Channel free of sediment and

open for navigation, Hains directed the construction of a tidal basin to separate the Potomac from the

Washington Channel. This tidal basin utilizes two sets of gates to allow water to enter the basin from

the Potomac during high tide and, when the tides begin to fall, to drain water from the basin and flush

the Washington Channel at each tidal cycle (National Parks Service). Now, 130 years after flooding

prompted the construction of the Tidal Basin and Washington Channel, the Army Corps is designing a

new flood protection levee system to protect the areas of the Mall and White House grounds that are

within the 100-year flood plain (Robarge, 2011).

GEOGRAPHIC DESCRIPTION

Categorized as an Estuary by the EPA, the Washington Channel has a water size of 0.3 square-

miles (U.S. Environmental Protection Agency, 2011). However, the EPA definition of an Estuary as a

“body of water formed where freshwater from rivers and streams flows into the ocean, mixing with

the seawater” is incongruent with the actual hydrology and location of the Washington Channel. Though

the Channel runs between Hains Point and Fort McNair/Southwest Waterfront, contiguous to the

Potomac and Anacostia Rivers and connected on its north end to the Tidal Basin, it does not serve to

connect freshwater with seawater (See Exhibit - 02). The U.S. Geological Survey identifies the

Washington Channel as a Channel and has a more apt definition of it as a “linear deep part of a body of

water through which the main volume of water flows and as a route for watercraft” (U.S. Geological

Survey, 1979).

The Washington Channel is identified by the EPA as being part of the Middle Potomac-

Anacostia-Occoquan Watershed. The Middle Potomac-Anacostia-Occoquan Watershed draws from

fifteen counties throughout the District of Columbia, Maryland and Virginia (See Exhibit - 03). The

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entirety of Washington, DC is within the Middle Potomac-Anacostia-Occoquan Watershed. Its upstream

watershed is the Middle Potomac-Catoctin and it feeds into the Lower Potomac downstream. The

Middle Potomac-Catoctin watershed reaches north through Maryland to the Pennsylvania boarder, to

the west deep into Virginia and to the eastern edge of West Virginia. The Middle Potomac-Catoctin is

fed by the Conococheague-Opequon, Shenandoah, and Monocacy watersheds which continue to reach

further into West Virginia, Virginia, and Pennsylvania. The Lower Potomac connects all the way down to

the Chesapeake Bay which feeds into the Atlantic Ocean (U.S. Environmental Protection Agency, 2011).

At the subwatershed level, the Washington Channel is part of the Pimmit Run-Potomac River

subwatershed (see Exhibit - 04). Additionally, the Rock Creek subwatershed discharges into the

Potomac immediately upstream from the Tidal Basin inlet which feeds the Washington Channel. The

watershed for the Washington Channel extends to the north to Independence Avenue, to the west to

15th St NW and midway across East Potomac Park, to bottom of Fort McNair and Hains Point to the

south, and as far as South Capitol Street to the east (see Exhibit - 05) (D.C. Department of Health, 2004).

In this way, the Washington Channel is one very small component in a large and complex basin and

watershed system. DC Water estimates that Washington, DC composes just one-half of one percent of

the overall Potomac watershed with the remaining 99.5% flowing from Virginia, West Virginia,

Maryland and Pennsylvania (see Exhibit - 06).

WALKING DESCRIPTION

Both the eastern and western banks of the Washington Channel are controlled by man-made

bulkheads or wall structures. There are no naturally occurring river banks along the length of the

Channel. The bulkheads along the eastern edge of the Channel were constructed as part of the

redevelopment of the Southwest Quadrant during the Urban Renewal effort that took place from the

1950’s – 1970’s. This concrete bulkhead runs in a straight line in a NW/SE orientation and replaced the

more varied and organic bulkhead and docklines that had developed along the working waterfront since

the 1790’s when Southwest was first settled. The existing promenade that runs parallel to the Channel

is roughly forty feet wide and is split between two elevations (see Exhibit – 07). The lower elevation is

at approximately +8’ while the upper elevation is approximately +13’. Along the eastern waterside of

the Channel are floating docks which are controlled by the Gangplank Marina and the Capital Yacht Club.

These docks extend approximately 250 feet into the Channel and run from the 600 block of Water St SW

all the way to the Maine Avenue Fish Market.

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The Maine Avenue Fish Market is further north on the Channel, just south of the Francis Case

Memorial Bridge/I-395/Southwest Freeway. The Fish Market is comprised of a series of floating barges

tied to a concrete pier where vendors sell raw and prepared seafood products (see Exhibit – 08). A fish

market has been in operation in approximately the same location (it was moved during urban renewal)

since the early 1800’s, well before the Washington Channel was dredged and channelized (Bahrampour,

2005). The piers allow for vehicular traffic and parking and sit at an elevation of approximately +5’.

Today, many of the barges are in poor physical condition and utility service to the barges appears to be

haphazard and likely non-compliant with modern codes.

Further north, the Washington Channel meets with the Tidal Basin at the tidal gates described

above. At this location are a series of low arched bridges which support 14th Street, Ohio Drive, and a

pedestrian walkway (see Exhibit – 09). This then leads to a path on East Potomac Park along the

western edge of the Washington Channel. Along East Potomac Park, a concrete sidewalk follows the

water’s edge for the perimeter of the park (see Exhibit – 10). This sidewalk is only one or two feet above

the water level (at time of observation) and the grade slopes up to meet the rest of the park. Much of

the sidewalk and the retaining wall are in poor condition and appear to have been washed away over

time (see Exhibit – 11). Based on lines of trash, debris, and other items that rested approximately

twenty feet away from the water’s edge, it was evident that flooding had recently occurred and that

there was a notable amount of foreign objects in the Washington Channel.

Regarding area imperviousness and land-use groups, the two sides of the Washington Channel

are greatly dissimilar. The eastern side of the channel is typified by concrete promenades, large format

restaurants and hotels from the 1970’s, over engineered asphalt roadways and service roads, and public

spaces that are predominately hard scape. There is very little pervious surface along the eastern side of

the Washington Channel from Fort McNair to the south and the eastern curbline of Maine Avenue to

the east. Based on the satellite imagery available on Google Maps1, Fort McNair, which starts south of P

Street, is primarily pervious. It is more typical of a traditional campus setting and has a high percentage

of grass lawns and other landscaped features intermixed with a variety of buildings, access roads, and

parking lots. However, on the west side, East Potomac Park represents a landscape that is almost

entirely permeable. Aside from a two-lane road that wraps around the park down to Hains Point, a few

small buildings, three parking lots, and a some athletic facilities, the entire park, the majority of which is

a public golf course, is a pervious grass lawn surface with landscaping. According to the Total Maximum

1 Fort McNair is not publically accessible and could not be walked for evaluation.

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Daily Load (TMDL) Decision Rational for Fecal Coliform Bacteria in the Washington Channel, fifty-three

percent of the Washington Channel watershed is comprised of government, commercial, and residential

development with the Channel itself covering approximately 25% of the watershed (See Exhibit - 12)

(United States Environmental Protection Agency, 2004).

ENVIROMENTAL INDICATORS / OVERALL HEALTH

According the the EPA’s Water Quality Assessment Status for Reporting Year 2010, the

Washington Channel is an impaired urban waterbody. The EPA has identified its waters as impaired for

the Protection of Human Health Related to Consumption Of Fish and Shellfish in 2010. Signs along the

water’s edge reinforce this risk to potential users (see Exhibit – 13). Since 1996, the EPA has found

causes of impairment that include Fecal Coliform, Organics, pH, Biochemical Oxygen Demand, and

Sediment (U.S. Environmental Protection Agency, 2010). The Tidal Basin, which feeds directly into the

Washington Channel and the Anacostia and mixes with the channel at it southern end, is also considered

to be an Impaired Waterbodies from a variety of non-point and point sources such as the Combined

Sewer Overflows (CSOs).

In December of 2004, a TMDL for the Tidal Basin and Washington Channel was created to help

ensure that the pollutants, namely Fecal Coliform, entering the waterbodies were within tolerable limits

and which would allow for water quality standards to be achieved. Fecal Coliform microbes, while not

harmful to humans, are an indicator of potential pathogens in the water which can cause illness and

disease. The Washington Channel, while not currently used for “primary contact recreation” (i.e.

swimming, water contact sports), is designated as a Class A waterbody and, therefore, must “be free of

discharges of untreated sewage, litter and unmarked, submerged or partially submerged, man-made

structures which would constitute a hazard to the users” (D.C. Department of Health, 2004, p. 3). The

TMDL for the Washington Channel and other Class A waters permit contamination that would,

statistically, estimate eight out of every one-thousand swimmers would contract an illness due to the

bacteria levels. To reinforce the impaired state of the District waterbodies, theTMDL specifically states

that the “District of Columbia water quality standards do not guarantee risk free primary contract

recreation nor do they guarantee that it can occur everywhere all of the time” (D.C. Department of

Health, 2004, p. 3).

The TMDL characterizes the potential sources of Fecal Coliform contamination as “ubiquitous”

and identifies CSOs, separate sanitary sewer overflows resulting from leaky or undersized sanitary pipes,

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and stormwater runoff which can cause direct deposits of feces into the waterbody from animal or

wildlife sources. While there are no CSOs that discharge into the Washington Channel, stormwater from

approximately 445 acres of land discharges through nine storm sewers into the Channel ( (D.C.

Department of Health, 2004). Data modeling in the 2004 TMDL found that there was no violation of the

water quality standards under existing loads and that the water bodies can safely carry the pollutant

loads that they are subjected to. Later studies indicated that the impact of storm water on Fecal

Coliform levels in the Washington Channel are negligible and that the levels of Fecal Coliform in the

Potomac River due to its upstream CSOs (see Exhibit - 14) may affect areas of waterbody that are close

to the tidal flap gate, but that the main cause of the Fecal Coliform levels in the Washington Channel is

controlled by the level in the Anacostia River and that the source is based in the sediment layer (Bai S.,

2006).

Being a man-made waterbody with high commercial activity, the Washington Channel has very

little value as a vegetative or wildlife habitat. The U.S Geologic Survey/Virginia Institute of Marine

Science Submerged Aquatic Vegetation report indicates that there is no Submerged Aquatic Vegetation

in the Washington Channel (U.S. Geolgic Survey/Virginia Intitute of Marine Science, 2007). Additionally,

the National Oceanic and Atmospheric Administration (NOAA) and National Marine Fisheries Service

have confirmed that there is a very low likelihood of the Washington Channel being a habitat for the

shortnose sturgeon, the only federally endangered marine animal in the vicinity of the Washington

Channel (Colligan, 2008).

HYDROLOGY

The Washington Channel is a tidal waterbody that has low areas along its banks which are prone

to flooding. The typical tidal fluctuations shown on the NOAA hydrograph indicate an anticipated high-

tide at approximately elevation +3.4’ and a low-tide elevation of approximately +0.2 ‘(see Exhibit- 15).

Flood stage for the Washington Channel is identified as +4.2’, with actionable levels at +4.0’, and

Moderate Flooding, which requires some evacuations of people and property, at +5.3’ (National Oceanic

and Atmospheric Administration, 2011). During the observed period of September 8th, 2011 to

September 12th, 2011, the Washington Channel reached flood level conditions seven times. In two of

those conditions the waters reached elevation +5.1, only two-tenths of an inch below the Moderate

Flooding level. While the weather patterns during this timeframe were atypically rainy, it illustrates the

point that the low lying areas along the Channel are highly susceptible to flooding.

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FEMA, the Federal Emergency Management Agency, sets the Flood Insurance Rate Maps for

jurisdictions around the country. These maps indicate what areas are within the 100-year and 500-year

flood plains, and of these, which areas have Base Flood Elevations (BFEs) that have been determined

and they set the requirements for mandatory flood insurance accordingly. The vast majority of East

Potomac Park, as well as the historic Maine Avenue Fish Market, are identified as sitting within the 100-

year flood plain (see Exhibit-16). This 100-year flood event would have a BFE of +11’. For low lying

areas such as the Fish Market, which sits at approximately elevation +5’, this means that there is a 1-

percent-annual-chance of a flood event that is approximately six feet deep, and a much higher

frequency for moderate level flood events (Federal Emergency Management Agency). Exhibit-16 also

identifies the flood risk to the National Mall that the Army Corps is currently working to mitigate

(identified as “Zone A”). With surface parking on asphalt lots and concrete piers being the predominate

land-use immediately surrounding the fish market, the flood events, even more minor ones, can

introduce road-based contaminants directly to the Channel and cause a risk to people and property at

the Fish Market. Fortunately, the majority of the vendors are situated on floating barges so they are

somewhat immune to the flooding risk. The remainder of the waterfront properties that are situated

along the upper promenade are above the 100-year floodplain but are still within the 500-year flood

plain, known as “Zone X” in FEMA parlance, and have a 0.2-percent-annual-chance of flooding.

WATERSHED GROUPS / RESTORATION EFFORTS

While there are no citizen groups that are dedicated exclusively to the improvement of the

Washington Channel and its watershed, there have been a number of programs that have been

implemented on a wider scale that have positive effects on the health and water quality of the

Washington Channel. These efforts include the implementation of a new Impervious Area Charges by

DC Water (formerly DC Water and Sewer Authority: DCWASA). These charges are designed to

encourage the creation of Low Impact Development zones and green roofs in lieu of traditional

impervious surfaces and serve to raise money that helps fund the completion of the federally mandated

Clean Rivers Project, also known as the Long-Term Control Plan, which works to control CSO discharges

(DC Water, 2011).

Other efforts, such as the Anacostia River Clean Up and Protection Act (also known as the “Bag

Fee”) and the Anacostia Watershed Initiative (AWI), which are geared primarily to benefit the Anacostia

River, have positive benefits on the health of the Washington Channel. The Bag Fee helps to reduce the

number of plastic bags that end up in all of the District’s waterways though imposing a 5-cent fee on

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each bag used. This helps to reduce pollution as a whole and is beneficial to the Washington Channel

(District Department of the Environment, 2010). The Anacostia Watershed Initiative has resulted in the

creation of stormwater management requirements that are much more stringent than those currently in

place in other areas of the District. These AWI regulations require the retention and reuse of

stormwater from a 1” storm event, and the filtration of an additional 2.2” of stormwater for properties

falling within its boundaries. The Washington Channel and the redevelopment area immediately

adjacent to the Channel are the only “non-Anacostia” properties that fall under the guidance and

jurisdiction of the AWI and its subsequent rulings and promulgations (Sarbanes, 2005).

The Washington Channel is a unique example of a man-made, highly urbanized waterway. Due

to the fact that the watershed network is both interconnected and interdependent, a change or

improvement that is made upstream of the watershed can sometimes have a positive change for the

health of the individual sub-watershed. It has been developed as part of a disaster mitigation and

prevention engineering solution, as well as a means to improve the economic vitality of marine-based

industries and merchants by providing an adequately dredged route for navigation. The Washington

Channel feeds from a relatively small immediate watershed, but its hydrology and health are integrally

linked to both the Potomac and the Anacostia Rivers.

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Exhibit – 01: Historic Photo of Dredging of Washington Channel

Source: (Robarge, 2011)

Exhibit – 02: Washington Channel Map

Source: (U.S. Environmental Protection Agency, 2011)

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Exhibit – 03: Middle Potomac Anacostia Occoquan Watershed Map

Source: (U.S. Environmental Protection Agency, 2011)

Exhibit – 04: DC Subwatershed Area Map

Source: (Federal Emergency Management Agency)

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Exhibit – 05: Washington Channel Watershed Map

Source: (D.C. Department of Health, 2004)

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Exhibit – 06: Multiple Jurisdictions Comprise Watersheds Map and Chart

Source: (DC Water and Sewer Authority, 2002)

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Exhibit – 07: View North Along East Side of Washington Channel

Exhibit – 08: Historic Maine Avenue Fish Market

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Exhibit – 09: Washington Channel Connection to Tidal Basin

Exhibit – 10: East Potomac Park Waterside Sidewalk

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Exhibit – 11: Deterioration of East Potomac Park Sidewalk

Exhibit – 12: Washington Channel Watershed Landuse Map

Source: (D.C. Department of Health, 2004)

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Exhibit – 13: Washington Channel Fishing Notice

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Exhibit 14 - Potomac and Rockcreek CSO Outfalls and CSS Drainage Areas

Source: (DC Water, 2004)

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Exhibit – 15: Washington Channel Hydrograph, 2011-09-13 through 2011-09-21

Source: (National Oceanic and Atmospheric Administration, 2011)

Exhibit – 16: District of Columbia’s Flood Insurance Map (FIRM)

Source: (Federal Emergency Management Agency)

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Works Cited

Bahrampour, T. (2005, August 30). On D.C. Waterfront, a Feast for the Senses. The Washington Post.

Bai S., L. W. (2006). ABSTRACT: Three-dimensional modeling of fecal coliform in the Tidal Basin and

Washington Channel, Washington, DC. Journal of Environmental Science and Health, 1327-1346.

Colligan, M. A. (2008, March 4). Letter to Richard Lehmann regarding information on shortnose

sturgeon. Gloucester, MA: Nationial Oceanic and Atmospheric Administration.

D.C. Department of Health. (2004, December). District of Columbia, Final Maximum Daily Loads for

Bacteria in the Tidal Basin and Washington Ship Channel. Retrieved September 23, 2011, from

www.ddoe.dc.gov:

http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/tmdl/xfinal.tidal.basin.pdf

DC Water. (2004, August). CSO Overflow Predictions for Average Year. Retrieved September 18, 2011,

from www.DCWater.com:

http://www.dcwater.com/wastewater_collection/css/CSO%20Overflow%20Predictions%20%20f

or%20Average%20Year.pdf

DC Water. (2011). Impervious Area Charge. Retrieved Septermber 18, 2011, from www.dcwasa.com:

http://www.dcwasa.com/customercare/iab.cfm

DC Water and Sewer Authority. (2002, July). WASA's Recommended Combined Sewer System Long Term

Control Plan - Executive Summary. Retrieved September 18, 2011, from www.dcwater.com:

http://www.dcwater.com/workzones/projects/pdfs/ltcp/Executive_Summary.pdf

District Department of the Environment. (2010, January 1). Skip the Bag, Save the River. Retrieved

Septermber 24, 2011, from green.dc.gov:

http://green.dc.gov/green/cwp/view.asp?a=1248&q=463102&PM=1

Federal Emergency Management Agency. (n.d.). Zone AE, NFIP Policy Index. Retrieved September 18,

2011, from www.fema.gov:

http://www.fema.gov/plan/prevent/floodplain/nfipkeywords/zone_a.shtm

National Oceanic and Atmospheric Administration. (2010, October). Chart 12289. Retrieved September

18, 2011, from Office of Coast Survey: http://www.charts.noaa.gov/OnLineViewer/12289.shtml

National Oceanic and Atmospheric Administration. (2011, September 18). Washington Channel :

Hydrograph. Retrieved September 18, 2011, from Advanced Hydrologic Prediction Service:

http://water.weather.gov/ahps2/hydrograph.php?wfo=lwx&gage=wasd2&view=1,1,1,1,1,1,1,1

&toggles=10,7,8,2,9,15,6

National Parks Service. (n.d.). Cultural Landscapes Inventory: Thomas Jefferson Memorial. Retrieved

September 18, 2011, from www.nps.gov:

http://www.nps.gov/thje/parkmgmt/upload/Jefferson%20Memorial%20CLI%20Part%202a%20-

%20History.pdf

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Robarge, D. (2011, March 28). Washington, D.C.'s 19th Century Reclamation Project. Retrieved

September 18, 2011, from The Atlantic:

http://www.theatlantic.com/technology/archive/2011/03/washington-dcs-19th-century-

reclamation-project/73078/

Sarbanes. (2005, July 22). Bill Text, 109th Congress, S.1472.S, Anacostia Watershed Initiative Act 2005.

Retrieved September 24, 2011, from thomas.loc.gov: http://thomas.loc.gov/cgi-

bin/query/F?c109:1:./temp/~c109EGFImB:e0:

U.S. Environmental Protection Agency. (2004, December 15). TMDL Document for Washington Ship

Channel. Retrieved September 18, 2011, from Watershed Assessment, Tracking, and

Environmental Results:

http://iaspub.epa.gov/tmdl_waters10/attains_impaired_waters.tmdl_report?p_tmdl_id=26252

&p_tribe=&p_report_type=

U.S. Environmental Protection Agency. (2010). 2010 Waterbody Report for Tidal Basin. Retrieved

September 18, 2011, from Watershed Assessment, Tracking, & Environmental Results:

http://iaspub.epa.gov/waters10/attains_waterbody.control?p_au_id=DCPTB01L_00

U.S. Environmental Protection Agency. (2010). District Of Columbia, Middle Potomac-Anacostia-

Occoquan Watershed. Retrieved September 18, 2011, from Watershed Assessment, Tracking,

and Environmental Results: http://iaspub.epa.gov/tmdl_waters10/attains_watershed.control

U.S. Environmental Protection Agency. (2010). Waterbody History Report for DCPWC04E_00. Retrieved

September 18, 2011, from Watershed Assessment, Tracking, and Environmental Results:

http://iaspub.epa.gov/tmdl_waters10/attains_wb_history.control?p_listed_water_id=DCPWC04

E_00&p_cycle=2010

U.S. Environmental Protection Agency. (2011, September 18). 2010 Waterbody Report for Washington

Ship Channel. Retrieved September 18, 2011, from Watershed Assessment, Tracking, and

Environmental Results:

http://iaspub.epa.gov/tmdl_waters10/attains_waterbody.control?p_list_id=DCPWC04E_00&p_

cycle=2010&p_report_type=

U.S. Environmental Protection Agency. (2011). Middle Potomac-Anacostia-Occoquan Watershed --

02070010. Retrieved September 19, 2011, from Surf Your Watershed:

http://cfpub.epa.gov/surf/huc.cfm?huc_code=02070010

U.S. Geolgic Survey/Virginia Intitute of Marine Science. (2007). Sugmerged Aquatic Vegetation 2007;

Washington West, Md. - D.C. - Va (28). Washington: VIMS, USGS.

U.S. Geological Survey. (1979, December 18). Feature Detail Report for: Washington Channel. Retrieved

September 18, 2011, from Geographic Names Information System (GNIS):

http://geonames.usgs.gov/pls/gnispublic/f?p=gnispq:3:4275305384430340::NO::P3_FID:529389

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United States Environmental Protection Agency. (2004, December 15). Decision Ratioinale Total

Maximum Daily Loads For Fecal Coliform Bacteria In Tidal Basin and Washington Ship Channel.

Retrieved Septermber 23, 2011, from www.ddoe.dc.gov:

http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/tmdl/xtidalb.dr.pdf

US Army Corps of Engineers. (2002, April). Historical Vignette 048 - The Corps' Connection to the

Washington, D.C., Tidal Basin and its Beloved Cherry Trees . Retrieved September 18, 2011, from

US Army Corps of Engineers: http://www.usace.army.mil/History/hv/Pages/048-

Cherry_Trees.aspx