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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-
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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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