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Constructed Wetlands Control Sedimentation in Wyoming's Muddy Creek
Waterbodv Improved Sedimentation due to failed irrigation structures and
1	 historical livestock grazing practices were responsible
for degrading the condition of Muddy Creek. In 1996 the Wyoming Department of
Environmental Quality (WDEQ) added a segment of lower Muddy Creek to the state's
Clean Water Act (CWA) section 303(d) list of impaired waters for threats to aquatic
life caused by habitat alteration (sedimentation). Partners reduced sedimentation by
rehabilitating irrigation infrastructure and constructing a large wetland complex. WDEQ
intends to remove sediment as a cause of impairment on this segment of lower Muddy
Creek from its 2014 CWA section 303(d) list.
Problem
Muddy Creek is a high-elevation, cold-desert
stream in south-central Wyoming's Little Snake
River Basin (Figure 1). The creek begins along the
continental divide within the northern foothills of
the Sierra Madre and flows southwest to its conflu-
ence with the Little Snake River. The lower portion
of Muddy Creek is protected by WDEQ for non-
game fisheries, fish consumption, aquatic life (other
than fish), recreation, wildlife, industry, agriculture,
and scenic value uses. The major land uses in the
Muddy Creek watershed are livestock grazing, oil
and gas development, and recreation.
In the 1970s-1980s, Muddy Creek was identified
as a substantial contributor of sediment to the
Little Snake and Yampa rivers in the Colorado River
drainage. The Muddy Creek watershed produces
naturally high sediment loads because of its highly
erodible soils. In addition, irrigation diversions
constructed by early homesteaders were breached
during the 1960s, causing severe headcutting,
gully erosion, and sedimentation in the creek. Also,
historical livestock grazing practices damaged
riparian areas and stream banks, increasing ero-
sion and sediment loading during precipitation and
spring snowmelt events. Chemical, physical, and
biological data collected in the mid-1990s indicated
that excessive sedimentation was threatening the
nongame fisheries and aquatic iife uses along a
17.5-mile section of Muddy Creek. As a result, this
segment (WYLS140500040104 _ 01) was added
to Wyoming's 1996 CWA section 303(d) list of
impaired waters.
Hgure 1. I he lower Muddy Creek watershed
Project Highlights
The Muddy Creek watershed became the focus
of extensive sediment remediation efforts begin-
ning in the early 1990s. Breached spreader dikes
(dam structures built across streams to spread
flows onto the adjacent iand) were repaired to
create the George Dew and Red Wash wetlands,
which together encompass most of the impaired
Subwatershed
Wyoming
Muddy Creek
0	1.5 3 6 9 Miles	Le9end
1	I I I	Segment WYLS140500040104 _ 01
Mainstream Surface Waters
C3 12-Digit Hydrologic Unit Boundary
Muddy Creek
Muddy Creek, Wyoming

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segment of Muddy Creek. This combined wetland
complex consists of water storage impoundments,
engineered channels, vertical drop structures,
headgates for diversions, overflow spillways,
and a braided channel stream network. Water is
either stored or released gradually back to Muddy
Creek's main channel. Coordinated Resource
Management (CRM) efforts led by the Little Snake
River Conservation District (LSRCD) beginning
in 1992 added to restoration efforts by address-
ing sedimentation caused by historical livestock
grazing. CRM is a framework to organize partners
(e.g., natural resource owners, managers, users) to
develop and implement management plans for all
major resources and ownerships within a specific
area. Through CRM, partners implemented a
number of best management practices, including
installing off-channel water sources for livestock,
adding riparian fencing, herding cattle away from
riparian zones, conducting prescribed burns,
planting riparian vegetation, and installing channel
stabilization structures.
Results
Repairing the wetland complex has greatly
decreased peak stream flows in the threatened seg-
ment of Muddy Creek. Following wetland and irriga-
tion infrastructure reconstruction, flow duration
intervals and peak flows were much higher above
the wetland complex than below. Data collected by
LSCRD between March and June during 2000-2003
indicate that monthly average discharge was 5 to
10 cubic feet per second higher above the wetlands
than below. Likewise, average peak discharge was
also higher above the wetlands than below. Thus,
the wetlands have greatly reduced the occurrence,
magnitude, and duration of the scouring stream-
flows that were causing accelerated erosion within
the impaired segment of Muddy Creek. As a result,
stream banks have stabilized and new vegetation
has grown. In addition to storing water, the wet-
lands act as a sediment filter that traps sediment
eroded from upstream sources. Turbidity was
used as a surrogate measure to estimate sediment
trends. Average monthly turbidity was compared
between monitoring sites, showing that turbidity
decreased 2-4 times from above the wetlands to
below (Figure 2). Moreover, basic water quality
parameters (pH, dissolved oxygen, turbidity, total
900
800
— 700
£	600
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j5	500
In
=	400
I1	300
ai
5 200
100
0 i	,	,	,—
March	April	May	June
Figure 2. Average monthly turbidity above (red) and
below (blue) wetlands between 2000 and 2003.
dissolved solids, and temperature) were found to be
within WDEQ's water quality standards, and values
remained relatively constant from 2000 to 2003.
WDEQ is proposing to remove sediment as a cause
of impairment on this segment of Muddy Creek
from its 2014 CWA section 303(d) list of impaired
waters.
Partners and Funding
CWA section 319 funds supported watershed resto-
ration efforts in the Muddy Creek watershed, includ-
ing efforts to stabilize, rehabilitate, and expand
the wetland complexes. LSRCD managed a total
of $752,952 in CWA section 319 funds to imple-
ment four project phases between 1993 and 2005
throughout the larger Muddy Creek watershed. In
addition, a total of $952,338 in non-federal match-
ing funds and $454,000 in other federal funding
supported the implementation of best management
practices, project effectiveness monitoring, and
coordination of the CRM and stakeholder involve-
ment. The LSRCD's major partners included the
Bureau of Land Management, Natural Resources
Conservation Service, Wyoming Game and Fish
Department, Wyoming Department of Agriculture,
WDEQ, Wyoming Water Development Commission,
Wyoming Natural Resource Trust Fund, Ducks
Unlimited, Wyoming Land Conservation Initiative,
U.S. Fish and Wildlife Service, and numerous
private landowners.
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-14-001SS
July 2014
For additional information contact:
Larry Hicks
Little Snake River Conservation District
Phone: 307-383-7860 • lsrcd@yahoo.com
Jennifer Zygmunt
Wyoming Department of Environmental Quality
Phone: 307-777-6080 • jennifer.zygmunt@wyo.gov

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