Q
A
NONPOINT SOURCE SUCCESS STORY
Riparian and Wetland Restoration Reduces Bacteria in Deep Creek
Waterbodies Imoroved A§ricultural sources contributed to impairment of Deep Creek
in the Idaho portion of the upper Palouse River Subbasin. First
identified as impaired in 1992, the Idaho Department of Environmental Quality (DEQ) included
four Deep Creek assessment units (Alls) on the 1998 Clean Water Act (CWA) section 303(d) list of
impaired waters due to bacteria, sediment and temperature. Watershed partners implemented
agricultural best management practices (BMPs) and stream and wetland restoration projects, which
reduced bacteria levels and prompted DEQ to propose to remove two Deep Creek AUs from the
impaired waters list in 2016 for bacteria.
Problem
Deep Creek Watershed Assessment Units
Deep Creek is in the Palouse River Subbasin in Latah
County in northwest Idaho. Agriculture, grazing,
forestry, residential areas and recreation are the major
land uses within this sparsely populated region. Most
of the land within the 42.75-square-mile Deep Creek
watershed is privately owned.
DEQ added Deep Creek to the 1992 CWA section
303(d) list of impaired waters based on best profes-
sional judgement of limited data submitted by the
Columbia River Intertribal Fish Commission. The 1998
CWA section 303(d) list included four Deep Creek
AUs: iD17060108CL032a_02, ID17060108CL032a_03,
iD17060108CL032b_02and iD17060108CL032b_03
(Figure 1). All AUs were listed as impaired for bacteria,
sediment and temperature.
Additional data were collected in 2001-2002 that
confirmed the impaired status of this watershed
for bacteria as well as sediment and temperature.
Samples from three monitoring sites in the Deep Creek
watershed showed exceedances of the state's second-
ary contact instantaneous water quality standard for
bacteria, which requires that Escherichia coll bacteria
concentrations in a single sample not exceed 576 E.
coli organisms/100 milliliters (rnL). Eight of 18 samples
collected across the three sites exceeded the E. coli
standard, with three samples showing levels exceeding
1,000 organisms/mL. In 2005 DEQ performed detailed
analyses on Deep Creek and developed total maxi-
mum daily loads (TMDLs) for bacteria, sediment and
temperature.
—1
1D17060108CL032a_02

ID17060108CL032b_02

ID17060108CL032a_03
—
ID17060108CL032b_03
palouse River
2 Miles
Figure 1. Deep Creek is in Idaho's upper Palouse River Subbasin.
Story Highlights
Beginning in 2006 the Palouse-Clearwater
Environmental Institute (PCEI), a community-based
nonprofit organization, led CWA section 319 grant-
funded efforts to decrease nonpoint source pollutant
loads into Deep Creek. In 2006 PCEI undertook the
Deep Creek Stabilization Project, which included
stabilizing streambanks (2,782 feet), restoring riparian
buffer areas that filter agricultural runoff, and installing
vestock-related BMPs (Figure 2). The project included
off-stream watering for livestock as well as a riparian
fence and hardened rock crossing to allow controlled
access to both sides of the creek.

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Figure 2. Photos of Deep Creek in 2005 (top) and 2008 (bottom)
show the restoration of the stream channel and riparian area.
In 2008 PCEI collaborated with the Latah Soil and
Water Conservation District (SWCD) to complete the
Deep Creek Riparian Restoration Project, part of a
larger Paiouse River watershed project developed by
the Paiouse Tributaries Watershed Advisory Group.
The project included stabilizing and revegetatirig
streambanks (1,070 feet). With heip from 25 student
volunteers from Washington State University, a
22,500-square-foot variable riparian buffer was plant-
ed with native woody, herbaceous and grass species to
help filter runoff before it reaches the creek. PCEI also
enhanced an existing wetland and created two new
wetland areas to help filter bacteria and nutrients in
runoff from a landowner's horse pasture.
Results
Implementation efforts have improved water qual-
ity in the Deep Creek watershed, as shown by DEQ's
5-year review of the Paiouse River Subbasin TMDL in
2016. Data collected during the review showed that
bacteria levels in both the uppermost and lowermost
Deep Creek AUs now meet the state's water quality
standard for bacteria, which requires that waters must
not contain more than a geometric mean of 126 E.
coli organisms/100 mL (based on a minimum of five
samples taken every 3 to 7 days over a 30-day period)
Table 1. Deep Creek 2013-2014 data show that the
lowermost and uppermost AUs in the Deep Creek
watershed meet water quality standards for bacteria.
Deep Creek
Assessment Unit
Sample
Dates
# of
samples
E.coli
range1
Geometric
Mean
ID17060108CL032b_03
6/4/2014-
6/24/2014
5
16-105.5
48
ID17060108CL032a_02
9/4/2013-
9/30/2013
5
5.2-135.4
31
1 Number of E. coli organisms/100 mL of water
or a single sample of 576 E. coli organisms/100 mL
(Table 1). Based on these data and implementation
efforts, DEQ proposes to remove the bacteria impair-
ment from two Deep Creek AUs in 2016: 032b_03
and 032a_02. Until additional AU-specific data can be
collected, AU 032b_02 will remain listed as impaired
for bacteria. DEQ is proposing to move AU 32a_03 to
the "unassessed" category because it is unlikely that
data have been collected due to challenges in obtain-
ing permission to access private property.
Partners and Funding
The Deep Creek Stabilization Project was supported
by $190,547 in 2006 CWA section 319 grant funds.
The Deep Creek Riparian Restoration Project was part
of a larger water quality improvement project (the
Paiouse River Water Quality Improvement Project)
that was supported by 2006 CWA section 319 grant
funds ($215,491) and local matching funds ($146,231
total). Local matching funds for the Paiouse River
project were provided by PCEI (community volunteers
and materials: $35,460), idaho Soil Conservation
Commission (technical staff: $16,825; BMP cost-
share: $21,450), landowners (BMPs: $30,000), Idaho
Association of Soil Conservation Districts/Latah SWCD
(field surveys: $6,000), University of Idaho (technical
staff and materials [TSM]: $8,574), Idaho Department
of Lands (TSM: $10,968), Potlatch Corporation (TSM:
$11,400), and the North Latah County Highway District
(TSM: $5,554).
This project succeeded because of the cooperation
between private landowners (including Buck Espy and
John Adler), Natural Resources Conservation Service,
PCEI, local and state organizations, university profes-
sors and students, students from local schools, and
many volunteers. DEQ's Lewiston Regional Office staff
conducted water quality monitoring.
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©
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-18-001H
March 2018
For additional information contact:
Sujata Connell
Water Quality Analyst, Idaho Department of
Environmental Quality
208-799-4370 • Sujata.Connell@deq.idaho.gov

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