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Section 319
NONPOINT SOURCE PROGRAM SUCCESS STORY
Watershed Restoration Efforts Reduce Turbidity in the Upper Illinois River
WWqtprhnrlv Imnrnx/prl Surface erosion and agricultural activities led to high turbidity
r -v, levels in the upper Illinois River in Arkansas. As a result,
the Arkansas Department of Environmental Quality (ADEQ) added a 2.5-mile segment of
the Illinois River to the state's 2006 Clean Water Act (CWA) section 303(d) list of impaired
waters for turbidity. The state applied a holistic mitigation strategy to abate sediment
runoff in the watershed. Turbidity levels on the listed reach declined, prompting the state to
remove it from the 2014 CWA section 303(d) list for turbidity impairment.
Problem
The Illinois River watershed is in northwest
Arkansas and northeast Oklahoma. It is a peren-
nial river with flow rates varying considerably from
year to year, depending on rainfall. The Illinois
River begins in the Ozark region of northwest
Arkansas, near Fayetteville, Springdale, Rogers and
Bentonville. The headwaters of the river meander
west through the Ozarks (Benton and Washington
counties) and cross into Oklahoma 5 miles south of
Siloam Springs, near the town of Watts, Oklahoma
(Figure 1).
ADEQ has listed the Illinois River as an Ecologically
Sensitive Waterbody (Figure 2). The Illinois River
is in the Arkansas River Basin, which is divided
into 10 discreet ADEQ planning segments based
on hydrological characteristics, human activities,
geographic characteristics, and other factors. The
upper Illinois River is in ADEQ planning segment 3J.
Erosion from agricultural areas led to high sediment
loading in the upper Illinois River. ADEQ considers
a stream reach in ADEQ planning segment 3J to be
impaired by turbidity if more than 25 percent of all
samples exceed 17 nephelometric turbidity units
(NTU), based on 5 years of data before the assess-
ment year. An assessment of data from the 5 years
leading up to 2006 (i.e., data from 2001-2005)
showed that 28 percent of water samples along
a 2.5-mile segment of the Illinois River exceeded
17 NTU. Therefore, ADEQ added this segment
(AR-3J-11110103-024) to the state's 2006 CWA sec-
tion 303(d) list of impaired waters for turbidity.
Illinois River
Watershed Landuse
USGS 2006 NLCD
d Barren Land (Rock/Sand/Clay)
• Cultivated Crops
_ Forest
• Developed/Urban
rn Pasture/Grassland
• Open Water
a WoodyWetlands
Figure 1. Land use within the Arkansas portion of the Illinois River
watershed. Agricultural areas surround the restored segment,
which is noted in orange. Urban area dominate the watershed's
eastern headwaters.
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Figure 2. The Illinois River is classified as an Ecologically Sensitive Waterbody in Arkansas.
Project Highlights
Beginning in 1998, the Arkansas Natural Resources
Commission (ANRC) used U.S. Environmental
Protection Agency CWA section 319 funds to pro-
vide Illinois River watershed landowners with finan-
cial and technical assistance to implement best
management practices (BMPs). These BMPs helped
reduce turbidity by preventing sediment from enter-
ing the water. Many landowners participated.
ANRC's watershed-wide approach included
participating in the startup of a watershed group,
contributing to development of an EPA-approved
nine-element watershed plan, implementing BMP
cost-share projects and demonstration projects,
conducting special watershed-targeted public
education projects (e.g., Urban Hispanic Outreach
and E-Education), and implementing low impact
development projects in urban areas.
BMPs implemented in the watershed include
riparian plantings (Figure 3) and rain gardens. Other
partners within the watershed have used private
funds and donations to continue some of the proj-
ects started by ANRC and develop their own water
quality projects to help improve and restore waters
in the Illinois River watershed.
Results
ANRC and its partners successfully addressed
surface erosion from agricultural activities through
cost-effective targeting of CWA section 319 funds.
As a result of the implemented practices in the
watershed, turbidity levels have been decreasing.
The 2014 ADEQ water quality assessment showed
that exceedances of the 17 NTU turbidity standard
for all flows had declined to 18 percent in the 5-year
period leading up to 2014. This level falls below
the 25 percent threshold, and meets water quality
standards. Therefore, ADEQ removed the turbidity
impairment for the 2.5-mile segment of the Illinois
River from its 2014 impaired waters list.
Partners and Funding
The water quality improvement in the Illinois
River is the result of partnerships between local
landowners in the watershed, the Benton County
Conservation District, the Washington County
Conservation District, ANRC, ADEQ, Arkansas
Game and Fish Commission, University of
Arkansas Water Resource Center, University of
Arkansas Cooperative Extension Service, Illinois
River Watershed Partnership, U.S. Department
of Agriculture's Natural Resources Conservation
Service and the U.S. Environmental Protection
Agency. Funding for BMP implementation was
provided by CWA section 319 funds in the amount
of $8,999,142; partners contributed $7,545,101.
Figure 3. Watershed stakeholders participate in a riparian restoration project along the upper Illinois River.
UJ
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001X
May 2015
For additional information contact:
Allen Brown
Arkansas Natural Resources Commission
Nonpoint Source Management Section
501-682-1611 • allen.brown@arkansas.gov
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