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Palisades Subbasin

Data Details
Hydrologic Unit Codes 17040104
Size 840 square miles (537,408 acres)
Water Bodies with EPA-Approved TMDLs (Category 4a) Antelope Creek, Bear Creek, Fall Creek, Indian Creek, Rainey Creek, Snake River
Beneficial Uses Affected Cold water aquatic life, salmonid spawning
Major Land Uses Forest, agriculture, grazing, range, recreation
Date Approved by EPA February 2001 EPA Approval Letter
Date Fall Creek TMDL Approved by EPA April 2004 EPA Approval Letter
Date Addendum/Five-Year Review Approved by EPA February 2014 EPA Approval Letter
Date Rainey Creek TMDL Approved by EPA July 2019 EPA Approval Letter

Subbasin Characteristics

The Palisades River subbasin drains to the South Fork Snake River in eastern Idaho. Public lands, predominantly forested, cover over two-thirds of the subbasin. The private lands are mainly rural properties used for agriculture. Impaired water quality in the subbasin is mainly caused by deposition of excess fine sediment due to roads, recreation, and livestock grazing in riparian areas.

2001 Subbasin Assessment and TMDL

Sediment TMDLs were developed for Antelope and Bear Creeks; the boundaries of the listed segments in both creeks were extended.

Camp Creek and Fall Creek are both listed with unknown pollutants. The TMDLs for these creeks were completed in 2004, as discussed below. In addition, the boundary of the listed segment of Fall Creek was extended to encompass the entire length of the creek.

Antelope Creek and both listed segments of the Snake River are impaired by flow alteration, but TMDLs were not prepared for this, as flow alteration is not considered a “pollutant” under the Clean Water Act, and TMDLs are not required for pollution, rather than “pollutants.”

The TMDL recommends that Elk Creek, Little Elk Creek, North Fork Indian Creek, and Sheep Creek be removed from the §303(d) list, as these segments all meet their beneficial uses and/or show no human impacts.

2001 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Stream Pollutants
Antelope Creek Sediment
Bear Creek Sediment

2004 Fall Creek Watershed Assessment and TMDL

This document addresses the water bodies in the Fall Creek watershed in the Palisades River subbasin that have been placed on the §303(d) list of impaired water bodies. TMDLs for the rest of the subbasin were completed in 2001 (discussed above). The Fall Creek watershed supports many valuable resources, including wildlife habitat, travertine hot springs, an aesthetically valuable 60-foot waterfall, and native Yellowstone Cutthroat Trout fisheries. The watershed is approximately 78 square miles (49,749 acres).

Sediment and temperature are the listed pollutants of concern in Fall Creek; sediment is the listed pollutant for Camp Creek. When the current excessive sedimentation in the upper watershed is reduced and riparian shade is increased, the Fall Creek watershed may rebound to be a unique and correctly functioning surface water system, fully supporting its beneficial uses according to water quality standards.

To fully support the beneficial use of cold water aquatic life, TMDLs are needed to control sediment in Camp and Fall Creeks. The goals are to achieve 80% streambank stability and 28% subsurface fine sediment. Additionally, a temperature TMDL is needed to reduce stream temperature to achieve salmonid spawning criteria in Fall Creek.

The US Forest Service is the land management agency in the Fall Creek watershed. In January 2002, the Caribou-Targhee National Forest recommended a number of improvements to the Fall Creek watershed and rated those improvements in order of importance. The TMDL goals should be attainable once these recommendations have been implemented.

2004 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Stream Pollutants
Fall Creek Sediment, temperature
Camp Creek Sediment

2013 Addendum

This document is an addendum to the 2001 subbasin assessment and TMDL and also serves as the TMDL 5-year review. This addendum addresses 10 assessment units (AUs) listed in Category 5 of Idaho’s 2010 Integrated Report. Investigation by DEQ showed that sediment was the main cause of impairment and that excess erosion in this subbasin is more significant from unstable, eroding streambanks than from upland erosion. Excess streambank erosion generally occurs during snowmelt and runoff in early spring, so DEQ measured the stability characteristics of streambanks at bank-full widths to determine the rate of excess erosion above natural background levels. A bacteria TMDL was written for Rainey Creek requiring a 50% reduction. This investigation showed that water quality targets are met in Squaw Creek, Iowa Creek, Trout Creek, South Fork Indian Creek, main form Indian Creek, Indian Creek (located off Fall River Road), North Fork Pine Creek, and Black Canyon Creek. Excess sediment was determined to be impairing water quality in two AUs of the Palisades River subbasin, requiring a 41% reduction on Hawley Gulch Creek, 57% reduction on Table Rock Canyon Creek, and 79% reduction on lower Indian Creek.

2013 Addendum: Streams and Pollutants for Which TMDLs Were Developed

Stream Pollutants
Snake River Sediment
Indian Creek Sediment
Rainey Creek Bacteria

2019 TMDL and Five Year Review

The 2019 TMDL and Five Year Review established a temperature TMDL on one assessment unit, Rainey Creek – source to mouth (ID17040104SK028_04), listed in Category 5 of Idaho’s 2014 Integrated Report. The temperature TMDL was developed using potential natural vegetation (PNV) methodology, which established water quality targets and load capacities, estimates existing pollutant loads, and allocates load reductions needed to return the listed waterbody to a condition meeting water quality standards based on the concept of riparian shade as the dominant influence of heat loading to streams. Additionally, the document reviews approved TMDLs for 11 AUs listed in Category 4a of Idaho’s 2014 Integrated Report.

2019 TMDL: Streams and Pollutants Which TMDLs were Developed

Description Assessment Unit Pollutant
Rainey Creek – source to mouth 17040104SK028_04 Temperature

Subbasin Document(s)

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DEQ Idaho Falls Regional Office
900 N. Skyline Drive, Suite B
Idaho Falls, ID 83402
Ph: (208) 528-2650
Fax: (208) 528-2695
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