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Sligo
Creek at a Glance
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Total
Area: 7,406 acres
Average Imperviousness: 35%
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Population:
81,943
Population Density: 7,081/mile2
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Forest
Cover (10%)
Acres
Deciduous: 554
Coniferous: 25
Mixed: 13
Shrub/Scrub: 119
Undefined: NA
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Wetland
Cover (<0.01%)
Acres
Emergent: NA
Forested: 0.25
Open Water: NA
Shrub/Scrub: NA
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Summary
Reference Information
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Sligo
Creek
is a free-flowing tributary of the Northwest Branch
of the Anacostia River; the stream joins the Northwest
Branch at the western city limits of Hyattsville. The
subwatershed is generally bound by Arcola Avenue and
University Boulevard to the north and east, Queen's
Chapel Road to the southeast, and the District of Columbia
and Georgia Avenue to the west. Seventy-five percent
of the subwatershed is in Montgomery County, with 20%
and 5% in Prince George's County and the District of
Columbia, respectively.
Dominant
Land Uses: The three largest land uses by area in
the Sligo Creek subwatershed are residential (75%),
forest cover (10%), and commercial (8%).
Physical
Characteristics: The Sligo Creek subwatershed is
7,406 acres (11.6 mi.2) in size and approximately 35%
impervious. Elevations range from 450 feet at the subwatershed
divide to 35 feet at the confluence with the Northwest
Branch. With an average gradient of 0.72% over 8.3 miles
of the mainstem, Sligo Creek flows from its headwaters
in the Piedmont physiographic province into the Coastal
Plain. The entire lower mainstem channel, from Riggs
Road to the confluence with Northwest Branch, has been
channelized.
Biological
Characteristics: Sligo Creek is designated a Use
I stream by the Maryland Department of the Environment
(MDE). The condition of fish and macroinvertebrate populations
in Sligo Creek has improved since the completion of
the first two phases of habitat restoration in the upper
third of the subwatershed. These efforts, which have
included controlling stormwater quantity and quality,
restoring both tributary and mainstem instream habitat,
creating wetlands, reforestation, and native fish and
amphibian reintroduction have resulted in aquatic habitat
rankings of greater than 70% (partially supporting)
of reference conditions at three mainstem sampling sites
(Cummins and Stribling, 1995). Although aquatic biota
are correspondingly healthier and more diverse than
during previous sampling, mainstem populations remain
impacted, scoring no better than 36% (moderately impaired)
of reference conditions (Cummins and Stribling, 1995).
Several physical barriers to both resident and anadromous
fish movement and migration are present downstream of
Riggs Road. These, as well as other barriers in Sligo
Creek, have been identified and remain as a restoration
challenge for this subwatershed.
Condition Summary: Sligo Creek is one of the
most urbanized subwatersheds within the Maryland portion
of the Anacostia watershed. Less than 15% of the total
subwatershed area remains undeveloped, and only 10%
of the subwatershed is in forest cover. The majority
of the stream is bordered by a narrow buffer of parkland
owned and maintained by the Maryland-National Capital
Park and Planning Commission (M-NCPPC). However, only
about 35% of the stream miles have an adequate riparian
forest buffer ( 300-foot total width). Initial indications
are that comprehensive stream restoration efforts in
the subwatershed, as well as fish re-introduction, have
been successful in partially restoring the aquatic ecosystem
of Sligo Creek (Cummins and Stribling, 1995). The impaired
condition of the aquatic biota that remains following
these efforts are attributable to how recently these
projects were completed and the need for additional
work. Planned future projects are to include stormwater
controls, wetland creation, habitat restoration, and
potentially additional fish reintroduction (Galli, 1996).
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