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Watershed Description – The Washington Channel
Natural Resources Planning: UAP 5414
Matthew Steenhoek
September 24, 2011
1
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
3
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.
4
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.
5
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,
6
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.
7
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
8
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.
9
Exhibit – 01: Historic Photo of Dredging of Washington Channel
Source: (Robarge, 2011)
Exhibit – 02: Washington Channel Map
Source: (U.S. Environmental Protection Agency, 2011)
10
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)
11
Exhibit – 05: Washington Channel Watershed Map
Source: (D.C. Department of Health, 2004)
12
Exhibit – 06: Multiple Jurisdictions Comprise Watersheds Map and Chart
Source: (DC Water and Sewer Authority, 2002)
13
Exhibit – 07: View North Along East Side of Washington Channel
Exhibit – 08: Historic Maine Avenue Fish Market
14
Exhibit – 09: Washington Channel Connection to Tidal Basin
Exhibit – 10: East Potomac Park Waterside Sidewalk
15
Exhibit – 11: Deterioration of East Potomac Park Sidewalk
Exhibit – 12: Washington Channel Watershed Landuse Map
Source: (D.C. Department of Health, 2004)
16
Exhibit – 13: Washington Channel Fishing Notice
17
Exhibit 14 - Potomac and Rockcreek CSO Outfalls and CSS Drainage Areas
Source: (DC Water, 2004)
18
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)
19
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21
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.
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Cherry_Trees.aspx