Nonpoint Source Success Story South Dakota Focused Implementation Reduces Bacteria in Butte County’s Horse Creek

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NONPOINT SOIREE SICEESS STORY

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Focused Implementation Reduces Bacteria in Butte County's Horse Creek

Waterbody Improved Bacter'a from agricultural nonpoint source pollution degraded

Horse and Indian creeks in Butte County, South Dakota. As a result,
the South Dakota Department of Agriculture and Natural Resources (DANR) placed Horse Creek on
South Dakota's 2016 Clean Water Act (CWA) section 303(d) list due to an Escherichia coli bacteria
impairment. Focused implementation of best management practices (BMPs), including riparian area
management, grazing management, and the conversion of flood irrigation to sprinkler systems in the
Horse Creek watershed, has reduced bacteria and lowered pollution to a level that allowed DANR to
remove Horse Creek from the 303(d) list of impaired waters in 2022.

Problem

Horse Creek flows through Butte County in western
South Dakota and drains 323,866 acres before merging
with the Belle Fourche River (Figure 1). Indian Creek
begins in Carter County, Montana, and merges with
Horse Creek west of Newell, South Dakota. Horse and
Indian creeks receive agricultural runoff,, as the water-
shed is 84% herbaceous rangeland and 15% cropland,
irrigated land, or pastureland. The remaining 1% of
land includes a confined feeding area, some reservoirs,
and municipalities and transportation.

To meet water quality standards for E. coli, no sample
can exceed 1,178 colony-forming units (cfu) per 100
milliliters (ml_); also, the geometric mean of a mini-
mum of five samples must not exceed 630 cfu/100
mL during a 30-day period. Horse Creek impairments
were identified during the Beiie Fourche Watershed
Implementation Project (2012-2022). As a result,

DANR added Horse Creek to the CWA section 303(d)
list of Impaired waters in 2016 for failing to attain Its
beneficial uses for limited contact recreation due to
elevated E. coli. Sources determined to have the most
impact on E. coli levels were grazing areas where
livestock had direct access to the stream and flood
irrigation events following winter-grazed cropland.

Story Highlights

Discussions between DANR and the Belle Fourche
River Watershed Partnership (BFRWP)— the sponsor
of the Belle Fourche River Watershed Implementation
Project—identified the Horse Creek watershed as a
good place to focus implementation projects. The
data showed that it could be improved enough to

Figure 1. Horse Creek is in western South Dakota.

meet water quality criteria. More than 50 producers
in the watershed implemented BMPs (see Figure 1 for
locations). Focused implementation In Horse Creek
started in Segment 8 of the Belie Fourche Watershed
implementation Project in 2017 to address the E. coli
listing. Watershed partners implemented various
BMPs, including grazing management, riparian restora-
tion and protection, and irrigation water management
(Figures2, 3, and 4).

Horse Creek
rBelle Fourche River
EHJ Counties

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Figure 2. Alternative water source

Producers implemented 68,667 acres of grazing man-
agement and 184 acres of managed riparian grazing in
the Horse Creek watershed (2007-2022). Also, produc-
ers installed 29,140 linear feet of livestock exclusion
fencing, which created a riparian buffer along Horse
Creek, and another 6,080 linear feet of pasture cross
fencing to better manage livestock distribution.
Agricultural producers installed approximately 76,630
linear feet of buried pipelines, supplying water to 43
water tanks/troughs to provide alternate watering
sources and support improved grazing management.
Most of the livestock water pipelines were connected
to rural water systems, but two water wells and pumps
were installed to provide alternate water sources.

In addition to the riparian and grazing management
practices, the project helped producers implement irri-
gation water management by converting 2,411 acres
of flood-irrigated fields to more efficient sprinkler
irrigation and converting earthen irrigation ditches
to buried pipelines in the Horse Creek watershed.
Agricultural producers replaced approximately 83,560
linear feet of earthen irrigation ditches by installing
21,156 linear feet of buried irrigation pipelines sup-
plying water to 35 pivot sprinkler systems to reduce
sediment and bacteria runoff within the watershed.

Results

Implementing improved grazing management along
the stream corridor, excluding livestock from access-
ing the stream, and converting flood-irrigated fields
to sprinkler systems led to reduced E. coli levels.
Samples before the focused implementation had
exceedances in seven of 55 samples (12.7%). Samples
after BMP implementation had exceedances in six of
85 samples (7%), According to STEPL modeling, BMP

Figure 4. Exclusion fencing

implementation also reduced loadings of nitrogen by
3,962 pounds; phosphorus by 2,791 pounds; and sedi-
ment by 6,009 tons in Horse Creek. As of 2022, Horse
Creek E. coli levels no longer violate water quality stan-
dards, and the creek has been removed from the 2022
CWA section 305(b)/303(d) list of impaired waters.

Partners and Funding

CWA section 319 funds specifically were used for
Installing livestock water pipelines and water tanks,
adding fencing to exclude livestock from direct access
to Horse Creek, converting irrigation systems from
flood to sprinkler systems, and burying irrigation
pipelines. Through several project segments over 15
years, CWA section 319 funds contributed $1,346,912
toward BMPs in the Horse Creek watershed. Other
federal sources provided funding for BMPs ($358,087),
including the U.S. Department of Agriculture Natural
Resource Conservation Service (NRCS) Environmental
Quality incentives Program, the U.S. Bureau of
Reclamation (USBR), and the U.S. Fish and Wildlife
Service (USFWS). Local sources, mainly landowners
and producers, contributed $2,408,919 for BMPs.

The local project sponsor is the Belle Fourche River
Watershed Partnership, which includes many part-
ners: participating landowners, the Butte, Lawrence,
and Elk Creek conservation districts; the Belle
Fourche Irrigation District; DANR; the South Dakota
Conservation Commission; South Dakota Game, Fish,
and Parks; the South Dakota Grasslands Coalition; the
South Dakota School of Mines and Technology; South
Dakota State University; U.S. Army Corps of Engineers;
USBR; USFWS; NRCS; U.S. Environmental Protection
Agency, U.S. Geological Survey; and the Wyoming
Department of Environmental Quality.

Figure 3. Sprinkler system

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

EPA 841-F-24-001A
January 2024

For additional information contact:

Kristopher Dozark

South Dakota Department of Agriculture and
Natural Resources

605-773-5682 • kris.dozark@state.sd.us

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