Protecting Public Health and the Environment.

Goose Creek Subbasin

Subbasin at a Glance

Hydrologic Unit Code 17040211
Size 692 square miles (442,880 acres) in Idaho
1,120 square miles (716,800 acres) total

Water Bodies with EPA-Approved TMDLs (Category 4a)

Beaverdam Creek, Birch Creek and tributaries, Cold Creek, Goose Creek, Little Cottonwood Creek, Trapper Creek, Trout Creek

Beneficial Uses Affected Cold water aquatic life, salmonid spawning, secondary contact recreation
Major Land Uses Range, forest, irrigated agriculture, urban
Date Approved by EPA July 2004
Approval Letter
Date Addendum Approved by EPA

April 2012
Approval Letter

Subbasin Characteristics

The general physical and biological characteristics of the Goose Creek subbasin have a strong influence on the water quality of the subbasin. Land use in the subbasin is predominantly rangeland. Irrigated agriculture also exists in the lower-elevation, northern portion of the subbasin where water is either pumped from the ground or diverted from Goose Creek Reservoir. The major population center of the subbasin is the town of Oakley. The subbasin contains three different water sources. The first is runoff from the snowpack and other precipitation events in the mountainous region to the east and west. The second is the Goose Creek-Golden Valley aquifer below Oakley, which is part of the Eastern Snake River Plain aquifer. The final source is a geothermal layer that feeds several geothermal springs along the ecoregional boundary.

2003 Subbasin Assessment and TMDL

The original TMDL document addresses the nine water bodies in the Goose Creek subbasin that were placed on the §303(d) list of impaired water bodies. Three additional water bodies (Emery Creek, Little Cottonwood Creek, and Left Hand Fork Beaverdam Creek) were also assessed based on past data that showed bacterial contamination.

The water quality of the Goose Creek subbasin is generally of high quality. Of the nine original listed water bodies, DEQ proposes to delist the following four: Lower Goose Creek Reservoir, Mill Creek, Blue Hill Creek, and Big Cottonwood Creek. Of the three additional water bodies, TMDLs were written for two; it was determined that Emery Creek is not impaired by bacterial contamination.

Goose Creek, Trapper Creek, and Lower Goose Creek Reservoir are listed for flow alteration. However, the US Environmental Protection Agency does not believe that flow (or lack of flow) is a pollutant as defined by the Clean Water Act. Since TMDLs are not required for water bodies impaired by pollution but not pollutants, TMDLs were not developed for flow alteration.

2003 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Goose Creek
Temperature, sediment
Trapper Creek
Nutrients, sediment
Birch Creek
Nutrients, bacteria
Cold Creek
Temperature
Beaverdam Creek
Nutrients, temperature, bacteria, sediment, dissolved oxygen
Little Cottonwood Creek
Bacteria
Left Hand Fork Beaverdam Creek
Nutrients, sediment, bacteria

2012 Addendum

This document addresses two water bodies in the Goose Creek subbasin that have temperature exceedances of water quality standards. Within the subbasin, Beaverdam Creek, Cold Creek, and Goose Creek were listed on the Idaho 1998 §303(d) list for temperature pollution. A temperature TMDL for these streams was completed in 2003; however, only the lower portion of Goose Creek from the Utah border to Goose Creek Reservoir was included. On the 2010 §303(d) list, upper Goose Creek and its tributaries and Trout Creek and its tributaries are included in the list of streams with impairments. Both of these remote streams are located in the Sawtooth National Forest and drain south from the Monument Peak area to the Nevada border.

This addendum developed temperature TMDLs for the upper Goose Creek and Trout Creek watersheds. Effective shade targets were established for the two stream systems based on the concept of maximum shading under potential natural vegetation resulting in natural background temperatures. Although additional stream reaches in Goose Creek were analyzed for shade and included in the overall analysis, they did not receive TMDLs due to lack of temperature data suggesting impairment.

2012 Addendum: Streams and Pollutants for Which TMDLs Were Developed

Upper Goose Creek and tributaries
Temperature
Trout Creek and tributaries
Temperature

Subbasin Documents


Staff Contacts

Water Quality Manager
Kiley Mulholland
DEQ Twin Falls Regional Office
650 Addison Avenue West, Suite 110
Twin Falls, ID 83301
(208) 736-2190
kiley.mulholland@deq.idaho.gov