NONPOINT SOIREE SICCESS STOIY
Educating Homeowners and Fixing Failed Septic Systems Restores
Recreation Use in North Piney Creek
A/ t h H I H Bailing septic systems contributed to elevated levels of Escherichia
VaterDOay I IprOVea colj(E colj) that exceeded the water quality criterion protective of
primary contact recreation in Wyoming's North Piney Creek. As a result, the Wyoming Department of
Environmental Quality (WDEQ) added North Piney Creek to Wyoming's 2006 Clean Water Act (CWA)
section 303(d) list of impaired waters. The local county government undertook proactive septic
system planning and education efforts and replaced or rehabilitated multiple septic systems in the
area. Monitoring between 2008 and 2010 indicated that E. coli concentrations in North Piney Creek
had declined and that the water quality criterion protective of primary contact recreation was now
being met, prompting WDEQ to propose removal of North Piney Creek from the state's 2014 list of
impaired waters.
Problem
Originating in the Big Horn Mountains, North Piney
Creek is a perennial stream protected by WDEQ for
drinking water, cold-water game and nongame fisher-
ies, fish consumption, aquatic life (other than fish),
recreation, wildlife, industry, agriculture and scenic
value uses (Figures 1 and 2). Its flows are derived
primarily from snowmelt within the upper reaches
of the watershed. Recreation and livestock grazing
are the primary land uses in most of the watershed,
but the lowermost 4 miles flow through the unincor-
porated community of Story. Land use within Story
consists of residential and rural residential proper-
ties of one-quarter acre to several acres, as well as
some larger agricultural properties. Story does not
have a central water supply or wastewater collection
system; therefore, each property typically contains a
private water supply well and septic system.
In 2005, allegations of surfacing sewage within a
Story subdivision prompted WDEQ to conduct a study
to evaluate £ coli contamination on several surface
waters in the area, including North Piney Creek.
Samples were collected from two sites on North Piney
Creekone above Story and one below. Samples
collected in 2005 indicated that above Story, the E.
coli criterion protective of primary contact recreation
(geometric mean of 126 colony-forming units (cfu) per
100 milliliters (ml) was being achieved in North Piney
Creek. However, samples from the site below Story
North Piney Creek, Wyoming
North Piney Creek
Legend
'** Previously Threatened Segment
-^ Mainstem Surface Waters
C3 12-Digit Hydrologic Unit Boundary
North Piney Creek Watershed |
O
WYOMING
Figure 1. Map of the North Piney Creek watershed.
indicated theE coli crite-
rion was being exceeded,
as samples resulted in a
geometric mean of 329
cfu/100 ml. This led to a
6.4-mile segment of North
Piney Creek (segment
WYPR100902060303_01)
being added to Wyoming's
2006 CWA section 303(d)
list of impaired waters for
nonsupport of primary
contact recreation.
Figure 2. North Piney Creek
is in northern Wyoming's
Sheridan County.
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Project Highlights
The CWA section 303(d) listing of North Piney
Creek, along with concerns of septic system effluent
contaminating the shallow alluvial aquifers used for
Story's domestic water supply, prompted Sheridan
County to undertake proactive efforts to address
the bacteria impairment. Work included the county's
sponsorship of a CWA section 205(j) project, one
of the goals of which was to educate the public on
water quality issues and the need for proper design
and installation of septic systems. The county
asked residents on a voluntary basis to allow county
personnel access to private properties to inspect
existing septic systems for a conditions assessment.
Mapping of groundwater depths and depth fluctua-
tions were accomplished, helping to better under-
stand the hydrogeology of the area and to identify
the areas most prone to problems. The project also
provided information on recommended well con-
struction standards. The county completed a review
of septic system permitting records within Story,
finding that roughly half of the 700 housing units did
not have septic system permits and some of the per-
mitted systems were out of date or inadequate. This
effort culminated in Sheridan County working with
Story residents to replace or rehabilitate multiple
septic systems and the development of the Story
Area Septic System Supplemental Regulations. The
supplemental regulations to Sheridan County Small
Wastewater Regulations required additional design
and construction requirements for septic systems
placed in the alluvial material in the Story area.
Results
At the request of Sheridan County, WDEQ com-
pleted follow up sampling on North Piney Creek
from 2008 to 2010 to determine if the bacterial
impairments had been mitigated. WDEQ collected
samples from North Piney Creek during the primary
contact recreation season (May through September)
in months corresponding to when samples were
collected in 2005. Five samples were collected in
a 30-day period (each sample separated by at least
24 hours) to calculate a geometric mean in accor-
dance with Wyoming's water quality criterion for
f. to// Geometric Mean (cfu/1 00 ml)
O-i CD O-i CD O-i CD i-n
NJCDCDCDCDCDCDCDCD
£ coli Geometric Means-North Piney Creek
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04 2005 2006 2007 2008 2009 2010 2011
Year
-- North Piney Creek above Story (NP1)
-- North Piney Creek below Story (NP2)
Primary contact recreation water quality criterion
Figure 3. Data show that North Piney Creek E. coli geometric
means dropped between 2005 and 2010.
E. coli. The geometric mean E. coli concentrations
obtained in 2008-2010 indicated thatE coli con-
centrations at both North Piney Creek sites (above
and below Story) attained the criterion protective of
primary contact recreation. Specifically, the geo-
metric mean concentration at the site below Story,
which had been 329 cfu/100 ml in 2005, dropped
to 80 cfu/100 ml in 2008, which met the water
quality criterion. Data showed that concentrations
dropped even lower in 2009 (42 cfu/100 ml) and
2010 (50 cfu/100 ml) (Figure 3). Geometric mean
concentrations at the North Piney Creek site above
Story attained the water quality criterion in all years
it was sampled. Therefore, the WDEQ has proposed
removal of North Piney Creek from the 2014 CWA
section 303(d) list of impaired waters.
Partners and Funding
CWA section 205(j) funds awarded to Sheridan
County through the state of Wyoming supported
water quality management planning efforts in the
watershed, leading to the voluntary rehabilitation
or replacement of multiple failed septic systems in
partnership with local residents. A total of $39,236 of
CWA section 205(j) funds and $19,986 of nonfederal
match contributed to this restoration effort.
I
5
s
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001VV
October 2015
For additional information contact:
Ken Muller
Sheridan County
307-674-2920 kmuller@sheridancounty.com
Jennifer Zygmunt
Wyoming Department of Environmental Quality
307-777-6080 jennifer.zygmunt@wyo.gov
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