NONPOINT SOURCE SUCCESS STORY
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Implementing Agricultural Conservation Practices Improves Turbidity
Levels in Middle Stillwater Creek
Waterbody Improved
Elevated turbidity levels resulted in the impairment of Stillwater
Creek and placement on Oklahoma's Clean Water Act (CWA)
section 303(d) list of impaired waters in 2004. Poor management of grazing lands, hay production
and croplands contributed to this impairment. Implementation of conservation practice systems
(CPs) to promote better quality grazing and crop land management decreased turbidity in the creek.
As a result, Middle Stillwater Creek was removed from Oklahoma's 2010 CWA 303(d) list for turbidity
impairment and now partially supports its warm water aquatic beneficial use.
Problem
Stillwater Creek flows through Noble and Payne coun-
ties before discharging to the Cimarron River in central
Oklahoma (Figure 1). Land use in the 176,640-acre
watershed is primarily grazing lands for cattle and
hay production. About 20 percent of the watershed is
forested and 5 percent is cropland. Approximately 10
percent of the watershed is developed land, including
the city of Stillwater (population 47,000).
Poor management of grazing and crop lands, develop-
ment, and stormwater runoff contributed to excess
turbidity in Stillwater Creek. The stream was listed
as impaired for turbidity in 2004 when 29 percent
of baseflow turbidity samples violated standards. An
Oklahoma stream is considered to violate the turbid-
ity standard when more than 10 percent of baseflow
samples are higher than 50 nephelometric turbidity
units (NTU). On the basis of these assessment results,
Oklahoma added the 16.43-mile middle segment of
Stillwater Creek (OK620900040070_10) to the 2004
CWA section 303(d) list for nonattainment of the warm
water aquatic beneficial use.
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A/3
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Ml City ol Stillwater
Stillwater Creek Watershed
Project Highlights
Landowners in the watershed worked with the Noble
and Payne county conservation districts, the U.S.
Department of Agriculture (LJSDA) Natural Resources
Conservation Service (NRCS), LJSDA Farm Services
Agency (FSA), and the Oklahoma Conservation
Commission (OCC) to implement CPs, which were
installed through NRCS's Environmental Quality
Incentives Program (EQIP), Wildlife Habitat Incentives
Figure 1. Stillwater Creek is in central Oklahoma.
Program, Conservation Stewardship Program (CStwP),
Conservation Security Program (CSP), and general
conservation technical assistance program. Additional
CPs were installed through FSA's Conservation
Reserve Program (CRP), the OCC's Locally Led Cost-
Share Program (LLCP), and with funding from the U.S.
Environmental Protection Agency's (EPA) CWA section
319 program.
From 2001 to 2010, landowners installed CPs to
reduce erosion and runoff, including 112,304 feet of
cross- and riparian-protection fencing, 14,400 acres of
prescribed grazing, 107 acres of critical area plant-
ing, 111 ponds, 32 watering facilities, 2,182 feet of
livestock pipeline, two wells, 597 acres of pasture and
hayland planting, 50 grade-stabilization structures,
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Middle Stillwater Creek, Turbidity
29% 31% 28% 9% 0% 0% 9%
3Qg exceedance exceedance exceedance exceedance exceedance exceedance exceedance
250
^ 200
£
,= 100
50
0
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2004 2006 2008 2010 2012 2014 2016
Figure 2. Monitoring data indicate that turbidity levels
in Stillwater Creek have declined.
174 acres of range planting, two heavy use areas, one
livestock winter feeding facility, 1,037 acres of forage
harvest management, 881 acres of nutrient manage-
ment, 5,669 acres of brush management, 3,112 acres
of prescribed burning, one water control structure,
513 acres of access control, 9 acres of riparian forest
buffer, 2,937 acres of integrated pest management
(IPM), six diversions, 1,448 acres of upland wildlife
habitat management, 47 acres of waste recycling,
and 121,256 feet of firebreak. Twenty-two improp-
erly designed or malfunctioning septic systems were
replaced or improved. One leaky septic lagoon was
replaced with an appropriately designed lagoon.
Landowners also implemented cropland CPs including
113 acres of conservation crop rotation, 395 acres of
conservation cover, 131 acres of no-till residue and
tillage management, 546 acres of reduced tillage or
mulch-till residue and tillage management, 10 grassed
waterways, 64 acres of filter strips, 11,033 feet of ter-
race, 1,406 feet of diversion, and 118 acres of seasonal
residue management.
Partners continued to implement CPs in 2011-2016,
including 197 acres of livestock access control, 2,209
acres of brush management, 244 acres of conservation
cover, 60 acres of conservation crop rotation, 14 acres
of continuous cover crops, 32 acres of critical area
planting, 30,253 feet of cross-fencing, 209 acres of
forage and biomass planting, 969 acres of forage har-
vest management, 15,102 feet of firebreak, 10 grade
stabilization structures, 1 acre of grassed waterway, 4
acres of heavy use area protection, 150 acres of IPM,
408 acres of nutrient management, 25 ponds, 450
acres of prescribed burning, 13,645 acres of pre-
scribed grazing, 30 acres of range planting, 1,255 acres
of no-till residue and tillage management, 1,186 acres
of reduced-till residue and tillage management, 286
acres of seasonal residue management, 55 acres of
split nitrogen applications, 1,534 acres of supplement/
feeding area rotation, 772 acres of upland wildlife
management, and four watering facilities.
Results
Through its statewide nonpoint source Rotating Basin
Ambient Monitoring Program, the OCC documented
improved water quality in Stillwater Creek due to
erosion-control CPs implemented by landowners.
Monitoring data compiled for the 2010 integrated
report showed that turbidity in Stillwater Creek had
decreased such that only 9 percent of baseflow sam-
ples exceeded 50 NTU; exceedances remained below
10 percent for the 2016 assessment (Figure 2). On the
basis of these data, the middle segment of Stillwater
Creek was removed from the Oklahoma CWA section
303(d) list for turbidity in 2010. Stillwater Creek now
partially supports its warm water aquatic beneficial
use. Monitoring will continue to ensure water quality
improvement is maintained and to document improve-
ment in its other two segments.
Partners and Funding
The OCC monitoring program is supported in part by
EPA CWA section 319 funds at an average annual state-
wide cost of $1 million. Approximately $500,000 in EPA
319 funds support statewide water quality educational
efforts through Blue Thumb. From 2001 to 2006, EPA
319 funds supported $146,337 worth of CPs, with an
additional $135,538 in state funding and with $165,965
in matching funds from landowners. From 2004 to
2016, NRCS supplied at least $412,000 to implement
CPs through EQIP, CStwP and CSP. Additional dollars
were provided through CRP. Additional funds were
provided through FSA for CRP practices. In addition,
a significant number of practices were funded by
landowners based on recommendations through
NRCS general technical assistance and conservation
planning. The LLCP provided $39,637 in funding for
CP installation which was matched by $73,945 from
cooperating landowners.
ss
HI
O
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-16-001Q
August 2016
For additional information contact:
Shanon Phillips
Oklahoma Conservation Commission
(405) 522-4500 • shanon.phillips@conservation.ok.gov
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