^tDsrx
f
^ I NONPOINT SOURCE SUCCESS STURY
Pistrict of CsQluwrifc
Stream Restoration and Trash Removal Efforts Improve Nash Run
Waterbody Improved
Nash Run, a first-order tributary of the Anacostia River, is impaired by
stormwater runoff from a highly impervious watershed. Stormwater
runoff has led to severe bed and bank erosion, contributing to diminished water quality and degradation
of instream habitat conditions. Nash Run was added to the 1996 Clean Water Act (CWA) section 303(d)
list of impaired waters for multiple pollutants. The Washington, D.C. (District) Department of Energy
and Environment (DOEE) used a legacy-sediment-removal stream design technique to reduce bank
erosion by creating a low and wide floodplain bench along the stream corridor. As a result, Nash Run
water quality has improved and is closer to attaining water quality standards.
Problem
Story Highlights
The headwaters of Nash Run are in Prince George's
County, Maryland, but 75 percent of the watershed is
within the borders of the District. The stream remains
piped from Prince George's County until it discharges
through an outfall west of Kenilworth Avenue in
northeast Washington, D.C. Once released from the
pipe, Nash Run flows through Kenilworth Marsh before
discharging into the Anacostia River.
The Nash Run sewer shed encompasses a 229-acre
area in the District, 112 acres (49 percent) of which
is impervious. The heavily urbanized character of
the watershed produces conditions for flashy and
intense stream channel flows even during moderate
storms. Large amounts of trash and debris wash out
of the storm sewer system during rain events, choking
portions of the stream and creating ponded areas that
support breeding mosquito populations. The hydro-
logic alterations to the stream degraded the water
quality of Nash Run and its natural habitat downstream
of the outfall. DOEE estimated that 33 tons of sedi-
ment per year were eroding from the stream banks of
Nash Run and washing downstream into the Anacostia
River. A 2008 study on trash estimated that Nash Run
produces approximately 3 percent of the total trash
from the District that washes into the Anacostia River.
Nash Run was first added to the CWA section 303(d)
list of impaired waters in 1996. The stream remained
listed as impaired as of 2016 for turbidity, flow
alternations, organic enrichment/oxygen depletion,
pathogens and other reasons.
The Nash Run Stream Restoration Project restored
1,400 feet of urban stream, turning a degraded stream
into both a community and environmental asset.
DOEE excavated over 9,000 cubic yards of soil along
the stream corridor and created a floodplain bench
that is 55 feet wide along the stream (Figures 1 and
2). The floodplain bench is one acre in size on both
sides of the stream and is planted with over 1,000
native grasses and herbaceous plants. It serves as a
grassy wetland complex adjacent to the stream and
allows the stream to spread out in storm events, thus
dissipating energy and reducing the stream's erosive
forces. Designs for the project began in 2011 and were
completed in 2015.
The project also included the installation of a floatable
trash trap, and two new culvert pipes underneath
a parking lot to help reduce the stream's 100-year
floodplain footprint, thus reducing the risk of flooding
affecting surrounding homes. In total, over 1,000 her-
baceous plants, 50 shrubs, and 99 trees were planted
along the restored stream corridor during restoration
work in 2016.
The restoration project was a community-based effort.
More than 20 private property owners signed tem-
porary easements allowing DOEE to conduct stream
restoration work on their property. Through com-
munity meetings, door-knocking, and being a constant
presence in the neighborhood DOEE built up a level
of trust with residents that fostered their continued
support for the project.

-------
Figure 1. Nash Run mid-stream in 2010 (before restoration). Figure 2. Nash Run mid-stream in 2018 (after restoration).
Results
initial post-restoration data (2017) shows that the
stream restoration work and trash trap installation is
a success. In 2017 the trash trap collected over 3,600
pounds of predominantly floatable trash. The increased
floodplain connectivity throughout the project area
reduced stream bank erosion and created a 1.08-acre
grassy floodplain wetland next to the stream.
Table 1. Fish count survey data in IMash Run before
2014-2015) and after (2016-2018) restoration.
Species
2014
2015
2016
2017
2018
American eel
12
40
-
2
-
Banded killifish
279
386
527
151
34
Blacknose dace
-
1
-
-
124
Creek chubsucker
1
2
-
-
12
E. mosquitofish
134
90
2,234
930
62
Green sunfish
48
29
-
3
-
Largemouth bass
-
-
1
-
1,029
Mummichog
158
341
59
280
41
N. creek chub
-
2
-
-
12
N. snakehead
1
-
-
-
366
Spottail shiner
-
-
-
-
36
Sunfish (other)*
7
-
-
-
17
White sucker
-
11
-
-
-
Total fish counts
640
902
2,821
1,366
1,733
* Sun fish (other) includes pumpkinseed, redbreast, bluegill and hybrid
species
Thanks to the project's success and the dedication of
DOEE and the local community, the Nash Run Stream
Restoration and Trash Trap Project was recognized as a
winner in the Chesapeake Stormwater Network's 2017
BUBBA [Best Urban BMP in the Bay Award] contest.
Since the completion of the restoration project, the
fish quantities and diversity have continued to increase
(Table 1). Although monitoring conducted immediately
post-restoration identified 2,821 individual fish, these
were limited to only four species of fish—the vast
majority of which were eastern mosquito fish. In the
summer of 2018, there were 10 species offish found
with a good distribution of fish per species. Overall,
the aquatic community index of biological integrity
for fish is now in the 'fair' range and is showing steady
improvements each year since restoration.
Partners and Funding
The partners involved in this project include the
National Fish and Wildlife Foundation (NFWF);
Johnson, Mirimam, and Thompson (the designer);
Environmental Quality Resources (the construction
contractor); the Environmental Protection Agency
(EPA) CWA Section 319 Program; the EPA Chesapeake
Bay Program; the Clean Water State Revolving Fund;
and DOEE. The total project cost (including design,
construction and monitoring) was over $3.5 million.
Funding included $400,000 from a NFWF grant, $1,025
million from the District's Bag Law, $1.1 million from
both the federal and local Clean Water State Revolving
Fund, $357,773 from the Chesapeake Bay Program,
and $337,221 from EPA's CWA Section 319 Program.
^tDSr-%
* ^ '
33
%
\
J
PRO"^
s
©
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-19-001UU
December 2019
For additional information contact:
Steve Saari
District Department of Energy and Environment
202-535-2961 • steve.saari@dc.gov

-------