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NONPOINT SOURCE SUCCESS STORY

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Watershed Planning and Partnerships Lead to Gunpowder Creek Delist ing

Waterbody Improved

The Kentucky Division of Water (DOW) added a 15-mile segment
of Gunpowder Creek (miles 0.0-15.0) to the 2002 Clean Water
Act (CWA) section 303(d) list/Integrated Report as impaired (nonsupport) for warm water
aquatic habitat (WAH) due to siltation and land development. After years of local improvements
to stormwater controls, agricultural conservation practices, watershed planning, and stream
restoration efforts, macroinvertebrate community data collected in 2014 indicated the segment
fully supports its WAH designated use. As a result, DOW delisted the sedimentation/siltation
impairment for this Gunpowder Creek segment in the 2018/2020 Integrated Report to Congress.

Problem

Gunpowder Creek drains into the Ohio River in northern
Kentucky (Figure 1). Gunpowder Creek is approximately
21.9 miles long and drains a 58.2-square-mile water-
shed dominated by forest (42%), urban areas (32%),
and agriculture (24%) in Boone County. The drainage
area is made up of two subwatersheds (Upper and
Lower Gunpowder creeks) and includes the cities of
Florence and Union. Biological sampling of Gunpowder
Creek (miles 0.0-15.0) in 1995-1999 indicated that
siltation caused this segment to fail to support the
aquatic life designated use, resulting in its placement
on the 2002 CWA section 303(d) list. Additional bio-
logical monitoring in 2011 confirmed this impairment,
and the stream remained listed on the 2016 CWA
303(d) list.

Story Highlights

in 2009, the CWA section 319(h) program awarded
over $501,000 to the Boone County Conservation
District to develop a Gunpowder Creek watershed
pian. This pian funded an extensive monitoring,
planning, and collaboration effort that identified
stormwater-driven sediment and bacteria as the
primary pollution sources of concern. Partners,
including the Boone County Conservation District, the
cities of Florence and Union, Sanitation District No.l
of Northern Kentucky (SD1), and DOW, identified prac-
tices such as stream restoration, stormwater retention,
and riparian buffers to mitigate siltation issues.
Northern Kentucky University's (NKU's) Stream and
Wetland Restoration Program helped restore 2,700
feet of stream in Florence with a history of erosion and

Figure 1. Gunpowder Creek is in northern Kentucky.

flooding (Figure 2). Restoration monitoring between
2009 and 2013 demonstrated that successful tree
plantings (more than 2,000 plantings/acre) widened
riparian buffers and Improved stormwater storage,
which helped to reduce erosion.

Additionally, several partners revised their stormwater
rules to limit stormwater runoff, including the City of
Florence (in 2005), Boone County (in 2012 and 2015),
and SD1 (in 2011 and 2012). SD1 further developed a
regional stormwater management program credit (in
2012) allowing property owners to receive a bill credit
for implementing best management practices (BMPs)
that improve water quality or stormwater runoff intensity.

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Gunpowder

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Legend

Watershed Planning Area
Delisted Gunpowder Creek
A NKU Stream Restoration Site |
Stormwater Systems
S83SD1
i i Florence
f:~~l Union


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Between 2000 and 2014. partners applied agriculture
BMPs to over 10,000 acres in the Upper and Lower
Gunpowder Creek watersheds with financial or
technical assistance from the Natural Resources
Conservation Service (NRCS). Additionally, over 14,800
linear feet of fence were installed to support rotational
grazing; stream exclusion, and other erosion-mitigating
agricultural practices.

Results

Following substantial watershed planning and col-
laboration,. new data demonstrates the Gunpowder
Creek segment (miles 0.0-15.0) is now supporting the
WAH designated use. Sampling between 1995 and
1999 classified the biological community as poordue
to siitation. In 2011, the macroinvertebrate community
was found to be fair using the macroinvertebrate
biological index (MBi). in 2014, the macroinvertebrate
community improved, and Gunpowder Creek scored
in the good MBi range. As a result, Gunpowder Creek
(miles 0.0-15.0) now meets its WAH designated use,
and sediment/siltation was delisted as part of the
2018/2020 Integrated Report to Congress.

Partners and Funding

The Gunpowder Creek watershed received
significant partner engagement, catalyzed through
the Gunpowder Creek Watershed Plan. In addition
to EPA and DOW, key partners include the Boone
County Conservation District, the cities of Florence
and Union, SD1, NKU, and Kentucky NRCS. In addition
to CWA Section 319 program funding ($501,056)
for watershed planning, NKU contributed $239,000
towards stream restoration, and Kentucky NRCS
funded $94,560 in agricultural BMPs (primarily in the
Lower Gunpowder Creek subwatersheds). The lasting
impact of watershed planning is evident in ongoing
collaborative investments, including installing new
stormwater basins, upgrading existing stormwater
basins (retrofits), constructing a bankfull stormwater
wetland (2017), and adding stream exclusion fencing
for livestock. Multiple stormwater improvement
projects are being developed with SD1, the City of
Florence, NKU, and the Cincinnati/Northern Kentucky
International Airport—these are likely to improve
water quality for years to come.

Figure 2. Stream restoration project in Gunpowder
Creek watershed.

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U.S. Environmental Protection Agency
Office of Water
Washington, DC

EPA 841-F-22-001J
June 2022

For additional information contact:

Josiah Frey

Kentucky Division of Water
502-782-0164 • josiah.frey@ky.gov


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