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Controlling Streamside Erosion and Urban Runoff Improves Water
Quality in Chena River and Chena and Noyes Sloughs
Waterbodies Improved Run°fffr°m urban areas and eroding culverts contributed
sediment to Alaska's Chena Slough, Chena River and Noyes Slough,
Alaska Department of Environmental Conservation (ADEC) added these three waterbodies to the
state's Clean Water Act (CWA) section 303(d) list of impaired waters due to sediment—Chena River
in 1990 and Noyes and Chena sloughs in 1994, Numerous restoration efforts have taken place since
the mid-1990s, including implementing best management practices (BMPs) to control stormwater
runoff and removing and replacing eroding culverts that restricted water flow. Data collected in
2011-2012 show that sediment levels met water quality standards, prompting ADEC to propose
removing all three waterbodies from the 2014/2016 list of impaired waters for sediment.
Problem
Chena Slough is a 16-mile-long perennial stream that
flows into the Chena River near the city of Fairbanks,
Alaska. Both Chena Slough and Chena River are popu-
lar and important fishery and recreational resources,
offering grayling fishing, salmon spawning habitat,
and boating (e.g., canoeing, kayaking, motor boating).
Noyes Slough is a 5.5-mile long side branch of the
Chena River in Fairbanks that provides wildlife habitat
(Figure 1). Flood-control structures installed over the
past 50 years on the Chena and Xanana rivers have
altered flow conditions in the Chena River watershed.
Erosion of streamside areas and stormwater runoff
from expanding urban areas around the cities of
Fairbanks and North Pole contributed sediment to the
Chena River and Noyes and Chena sloughs. Bank ero-
sion occurs along most of the Chena River, and is most
prevalent along the river during the two annual peaks
in discharge: spring snowmelt runoff and late summer
precipitation. Several upper tributaries of the Chena
River have been or are currently being mined for gold,
which could contribute sediment to the system.
The sediment standard requires that there be "no
measurable increase in concentration of settleable
solids above natural conditions, as measured by the
volumetric Imhoff cone method." Because the three
waterbodies failed to meet the standard, ADEC added
them to the CWA section 303(d) list for sediment
(Chena River: 1990, Chena and Noyes sloughs: 1994).
Fairbanks
Noyes
sl°usb Chena River
Fairbanks
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Fort
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Map adapted from image developed by Ben Kennedy,
USGS Water Resource Division.
Figure 1. The Chena River and Chena Slough are in eastern
Alaska's Tanana River watershed.
Story Highlights
Efforts to address sediment and other pollution
sources in the Chena River and Noyes and Chena
sloughs drainage basins have been underway for
decades. The Noyes Slough Action Committee coordi-
nated several volunteer clean-up events in 1999-2002
to remove log jams and other debris to restore water
flow to the slough and enhance habitat. In 1999 the
Army Corps of Engineers (COE) stabilized a Chena

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Figure 2. Partners replaced small culvert pipes (left)
along Chena Slough with a new bridge (right) that
allows the water to flow freely.
River streambank that was eroding due to recreational
uses (boat wakes and angler foot traffic). In 1999 the
city of Fairbanks, in conjunction with the University
of Alaska-Fairbanks (UAF), received a CWA section
319 grant from ADEC to support a 1999-2003 project
to develop a map, inventory, and model of the city's
stormwater drainage system. Additional section 319
grants allowed the city to prioritize potential sedimen-
tation sources (2002) and assess water quality and
BMP effectiveness (2004).
In 2000 the Alaska Department of Fish and Game
(ADF&G) published a guidance pamphlet, Chena River
Bank Stabilization, to help landowners restore stream-
banks using riprap gabions, sandbags, concrete biock
retaining walls, log berms, earthen berms, and bioen-
gineered stabilization, in the early 2000s; the USFWS
worked with local stakeholders to stabilize 195 feet of
streambank near Fairbanks.
Stakeholders have been working for years to improve
water flow in Chena Slough. Hydrological modifica-
tions in the watershed contributed to decreased
water flows, which encouraged flooding and allowed
upstream sediments to accumulate in the slough and
then erode under high water flow conditions. Between
2001 and 2009, partners replaced four poorly func-
tioning culverts with new bridges (Figure 2).
Since the area's municipal separate storm sewer
system permit went into effect in 2005, the committee
has implemented many activities that exceeded the
minimum permit requirements, including encouraging
rain barrel use, holding annual river-related education
events, conducting an annual storm drain art event,
and promoting the use of green infrastructure.
In 2009-2011, ADF&G implemented the Fairbanks
Restoration Cost Share project, a financial incentive
and educational outreach program that provides
funding and technical project design assistance for
landowners to restore streambanks to rehabilitate and
sustain salmon habitat. From 2009 to 2011, the pro-
gram helped fund nine projects in the Fairbanks area,
almost all along the Chena River, restoring approxi-
mately 2,250 liner feet of streambank.
Results
The partners' combined efforts have reduced the
amount of sediment reaching waterways. ADEC
collected water samples and visually assessed the
waters in 2011-2012 under various flow regimes and
compared them to upstream reference sites. All sites
had results consistent with the reference sites; most
results for all sites were either reported as 0 milliliters
per liter (ml/L) settleable solids or were below the
method reporting limit (MRL). in 2011-2012 the Chena
River had two samples at the MRL of 1.0 ml/L. The
Chena Slough also had two measurable samples (2 and
6 ml/L). All 2011-2012 samples for Noyes Slough
were below the MRL. All sample results for settleable
solids, at both reference and downstream sites, were
comparable. This satisfies the water quality standard,
prompting ADEC to propose removing the three seg-
ments from the 2014/2016 list of impaired waters for
sediment.
Partners and Funding
Numerous partners have worked to improve water
quality in the area, including UAF, COE, USFWS,
ADF&G, ADEC, and local groups. Funding for the
2002-2009 culvert replacement project included a
$75,000 National Fish and Wildlife Foundation grant
and $374,000 in state grant monies from the offices
of Senator Therriault ($250,000) and Representative
Coghi'l ($124,000), among other sources. Beginning
in 1999, Fairbanks used CWA section 319 funds to
(1) map, inventory, and model Fairbank's stormwater
drainage system to allow better management (1999-
2004: $541,500), (2) prioritize potential sedimentation
sources (2002: $60,414), and (3) assess water quality
and BMP effectiveness (2004: $175,000).
0
PRO^°
s
©
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-19-001N
April 2019
For additional information contact:
Chandra McGee
Alaska Department of Conservation
907-451-2140 • chandra.mcgee@alaska.gov

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