Section 319
NONPOINT SOURCE PROGRAM SUCCESS STURY
Implementing Grazing Best Management Practices Improves Shoshone Creek
Waterbody Improved
Recreation, livestock grazing and other activities on public and
private lands along southern Idaho's Shoshone Creek led to erosion
and the loss of riparian cover. Data indicated that the creek failed to meet its beneficial uses for cold
water aquatic life and salmonid spawning because of sediment and temperature impairments. As a
result, numerous portions of Shoshone Creek were included on the Clean Water Act (CWA) section
303(d) list between 1994 and 2008. Public and private partners have implemented best management
practices (BMPs) to reduce erosion and improve riparian conditions. Recent bioassessment data
collected along South Fork Shoshone Creek indicate that water quality conditions are improving as a
result of restoration efforts.
Problem
The 218,600-acre Shoshone Creek watershed is
west of Idaho's Cassia Mountains in Twin Falls
County and drains into Salmon Falls Creek in Elko
County, Nevada (Figure 1). Landowners include
the U.S. Department of Interior's Bureau of Land
Management (BLM) (44.7 percent), the U.S. Forest
Service (USFS) (20.3 percent), the Idaho state gov-
ernment (2 percent) and private entities (33 percent).
Rangelands encompass approximately 58 percent
of the Shoshone Creek watershed. Historical grazing
systems allowed cattle to heavily graze meadows
and riparian habitats, causing decreased stream-
bank stability and damaging native vegetation. This,
in turn, allowed for the invasion of noxious weeds,
a loss of beneficial riparian vegetation and the ero-
sion of soil. Data collected in the 1990s and 2000s
indicated that Shoshone Creek failed to support its
beneficial uses (cold water aquatic life and salmonid
spawning) because of elevated temperatures and
excess sediment. As a result, numerous assessment
units (AUs) within the Shoshone Creek watershed
were added to the CWA section 303(d)list — two by
the U.S. Environmental Protection Agency in 1994
and two by the Idaho Department of Environmental
Quality (DEQ) in 2008.
In 2007 DEQ completed a subbasin assessment and
total maximum daily load (TMDL) for the listed AUs
within the Salmon Falls Creek subbasin, including
those in the Shoshone Creek watershed. To allow
Shoshone Creek to meet water quality standards and
support its beneficial uses, the TMDL established
reduction goals for both temperature (a 40 percent
reduction) and sediment (a 65 percent reduction).
Figure 1. Shoshone Creek is in
southern Idaho. Yellow dots represent
monitoring locations in the upper
portion of Shoshone Creek AU
ID17040213SK016 _ 03 (main stem).
Project Highlights
Partners have worked to improve Shoshone Creek
since the early 1980s. For example, in the Magic
Common Grazing Allotment, BLM excluded live-
stock from the stream (0.15 mile and 0.25 mile in
1982 and 1987, respectively), instituted prescribed
grazing in 2000 and installed fencing to protect a
sensitive spring in 2003. In the Kerr-Lost Allotment,
BLM excluded livestock from 0.25 mile of Shoshone
Creek in 1982 and instituted prescribed grazing
in 1987. In 2000 BLM adopted prescribed grazing
in the Horse Creek Allotment. As of 2014, all of
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Shoshone Creek under BLM administration is either
excluded from livestock grazing or is managed as
riparian pasture (i.e., allows for prescribed grazing).
In July 2013, staff from the USFS' Sawtooth
National Forest developed a land and resources
management plan that describes the agency's
water management goals. Even before developing
this plan, the USFS was implementing projects to
protect soil, water, riparian and aquatic resources.
In 2004 the USFS built fences on the Rock Creek
C&H Allotment to restrict grazing along the creek. In
addition, the USFS placed boulders along the main
road to prevent motor vehicle access to the creek.
Table 1. South Fork Shoshone Creek Beneficial Use
Reconnaissance Program Wadeable Streams Rapid
Bioassessment Data
In 2007 the USFS part-
nered with the Twin
Falls Soil and Water
Conservation District
(SWCD)and the
Western Stockgrowers
Grazing Association
(WSGA)to install pip-
ing from a spring to a
10,000-gallon holding
tank. The water is then
gravity-fed to 19 live-
stock watering troughs
(Figure 2). These
troughs serve three
different grazing pastures as part of a rotational
grazing system on 2,354 acres and help to protect
approximately 4 miles of Shoshone Creek riparian
area. The WSGA and USFS developed and imple-
mented a grazing management plan for the area in
2008. To supplement water supplies during drought
periods, they installed a second, 6,000-gallon stor-
age tank, in June 2014. The WSGA also purchased
two mobile pumps powered by solar panels to
provide additional alternative water sources.
Figure 2. Project partners installed
alternate water sources to keep
livestock away from Shoshone Creek.
Results
DEQ collected Beneficial Use Reconnaissance
Program wadeable streams rapid bioas-
sessment data in the upper portion of AU
ID17040213SK016 _ 03 in 1997, 2005 and 2011.
These limited data, which capture and assess only
the uppermost few miles of an 11.3-mile-long AU,
show that the macroinvertebrates scores have
improved from a condition rating of 2 to 3 (Table 1).
The habitat is also responding favorably, but at a
slower pace. The SFI (stream fish index) score did
Date
1997
2005
2011
Stream
Macroinvertebrate
Index (SMI) Score
44.9
58.5
72.4
SMI
Condition
Rating1
2
3
3
Stream Habitat
Index (SHI)
Score
46
43
53
SHI
Condition
Rating1
1
1
2
1 The SMI, SFI and SHI results are used to evaluate support of cold water aquatic
life. The scoring criteria are derived from percentile categories of the reference
condition in different bioregions (i.e., a "condition rating"). Condition ratings
include 0 (below minimum of reference condition), 1 (less than 10th percentile
of reference condition), 2 (between 10th and 25th percentile of reference condi-
tion), or 3 (more than 25th percentile of reference condition). For more informa-
tion, see section 6 of Idaho's Water Body Assessment Guidance (January 2002).
not improve over the sampling period; however,
numerous native fish species have been present
during all sampling events. Juvenile salmonid spe-
cies were present in both 1997 and 2011, indicating
good quality water. DEQ believes that the low SFI
score might not reflect conditions on-the-ground;
therefore, additional fish surveys are warranted.
These data indicate that restoration efforts are
helping to improve water quality in the upper por-
tion of Shoshone Creek AU ID17040213SK016_03.
Additional data will need to be collected to assess
water quality conditions elsewhere within this and
other Shoshone Creek AUs.
Partners and Funding
Numerous partners have provided technical
or financial assistance to help landowners and
producers implement BMPs in the Shoshone Creek
watershed. Partners include the Twin Falls SWCD,
USFS, BLM, the WSGA, the U.S. Department of
Agriculture's Natural Resources Conservation
Service, and the Idaho Soil and Water Conservation
Commission.
The Twin Falls SWCD received $96,160 ($85,700
in 2007 and $10,460 in 2014) in U.S. Environmental
Protection Agency CWA section 319 funding
from DEQ to install storage tanks, piping and
water troughs to support rotational grazing. The
WSGA provided significant matching funds for
the CWA section 319 projects. DEQ and the Idaho
Association of Soil Conservation Districts have col-
lected monitoring data and have provided support
for assessment and planning efforts.
UJ
O
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-14-001GGG
September 2014
For additional information contact:
Katie Shewmaker
TMDL Implementation Coordinator
Idaho Department of Environmental Quality
208-736-2190 • Katie.Shewmaker@deq.idaho.gov
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