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              Section 319
              NDNPDINT SOURCE PROGRAM SOGGESS  STORY
 Turbidity Levels in Mill Creek Decline After Agricultural Best Management
 Practice Implementation
Waterbody Improved
                              High turbidity, due in part to practices associated with
                              cattle  production, resulted in impairment of Mill Creek and
placement on Oklahoma's Clean Water Act (CWA) section 303(d) list in 2004.  Implementation
of best management practices (BMPs) to promote better quality grazing land decreased
sediment loading into the creek. As a result, a 24-mile-long segment of Mill  Creek was
removed from Oklahoma's 2010 CWA 303(d) list for turbidity impairment. This segment of
Creek is currently in  partial attainment of its fish and wildlife propagation designated use
and has been proposed for full attainment of the use in the 2014 integrated  report.
 Problem
 Mill Creek is in Mclntosh County in central-eastern
 Oklahoma. Land use in the 41,669-acre watershed
 is primarily rangeland and pasture for cattle produc-
 tion, with a small amount of corn production as
 well. Poor grazing land management contributed
 to excess sedimentation in the watershed. In the
 2004 water quality assessment, monitoring showed
 that 40 percent of Mill Creek's seasonal base flow
 water samples exceeded 50 nephelometric turbid-
 ity units (NTU). A stream is considered impaired by
 turbidity if more than  10 percent of the seasonal
 base flow water samples exceed 50 NTU (based
 on five years of data before the assessment
 year). On the basis of  these assessment results,
 Oklahoma added a 24-mile-long segment of Mill
 Creek (OK220600010100 _ 20) to the 2004 CWA
 section 303(d) list for  nonattainment of the fish and
 wildlife propagation designated use due to turbidity
 impairment.
                                          Figure 1. The
                                          Oklahoma.
Creek watershed is in central-eastern
 Project Highlights
 Landowners implemented BMPs with assistance
 from Oklahoma's locally led cost-share program and
 through the local U.S. Department of Agriculture's
 Natural Resources Conservation Service (NRCS)
 General Conservation Technical Assistance
 Program, Grazing Lands Conservation Program and
 Environmental Quality Incentives Program (EQIP).
 From 2005 to 2009, landowners improved pasture
 and range condition with more than 15,000 acres
 of prescribed grazing, installation of 29 ponds for
                                          alternative water sources, 11,920 linear feet of
                                          fencing, 6,175 acres of integrated pest management
                                          and 5,793 acres of upland wildlife habitat manage-
                                          ment. Erosion from cropland was reduced through
                                          239 acres of reduced tillage and mulch-till methods,
                                          353 acres of nutrient management and 37 acres of
                                          forage planting and harvest management.

                                          From 2010 to 2012, additional BMP implementation
                                          further improved grazing lands and kept erosion
                                          potential low. Twenty additional ponds were
                                          installed, along with more than 8,400 feet of fenc-
                                          ing, to  promote optimal grazing on approximately
                                          4,000 acres. Nutrient management was imple-
                                          mented on 3,639 acres, and brush management,
                                          integrated pest management and supplemental

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planting on more than 1,500 acres helped enhance
pasture condition. Finally, rangeland was improved
through 6,000 acres of grazing management for
wildlife habitat through the NRCS Conservation
Stewardship  Program.
Results
The Oklahoma Conservation Commission's Rotating
Basin Monitoring Program, a statewide nonpoint
source ambient monitoring program, documented
improved water quality in Mill Creek due to land-
owners implementing BMPs. In the 2004 assess-
ment, 40 percent of seasonal base flow water
samples exceeded the turbidity criteria of 50 NTU.
This exceedance was reduced to 8 percent in
2010, and the 24-mile segment of Mill  Creek was
removed from Oklahoma's CWA section 303(d) list
for turbidity impairment. Turbidity has  continued to
decline, with a zero percent exceedance in the 2012
assessment. This segment of Mill Creek is currently
in partial attainment of the fish and wildlife propaga-
tion designated use and has been proposed for full
attainment of this use due to further improvements.
Partners and Funding
The Rotating Basin Monitoring Program is support-
ed by the U.S. Environmental Protection Agency's
CWA section 319 program at an average annual cost
of $1 million. Monitoring costs include personnel,
supplies and lab analyses for 18 parameters from
samples collected every 5 weeks at about 100 sites.
In-stream habitat, fish and macroinvertebrate sam-
ples  are also collected. Approximately $600,000
80-
5
1—
5 60-
15
= 40-
|
8 20-
ro
CO
0-
Mill Creek
40% exceedance 29% exceedance 8% exceedance 0% exceedance


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2004 2006 2010 2012






Assessment Year
Figure 2. Monitoring data indicate that base flow turbidity levels
in Mill Creek (segment OK220600010100 _ 20) have declined.
in CWA section 319 funding supports statewide
education, outreach and monitoring efforts through
the Blue Thumb program. The Oklahoma cost-
share program provided approximately $13,000 in
state funding for BMPs in this watershed through
the Mclntosh County Conservation District. NRCS
spent approximately $485,000 for implementation
of BMPs in Mclntosh County from 2005 to 2009.  An
additional $615,684 was spent from 2010 to 2012
to maintain these practices and continue to pro-
mote good grazing land management. Landowners
provided a significant percentage of funding toward
BMP implementation in these programs as well.
UJ
(9
     U.S. Environmental Protection Agency
     Office of Water
     Washington, DC

     EPA841-F-14-001DDD
     September 2014
For additional information contact:
Shanon Phillips
Oklahoma Conservation Commission
405-522-4500 • shanon.phillips@conservation.ok.gov

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