Brownlee River (Weiser Flat) Subbasin

Subbasin at a Glance

Hydrologic Unit Codes	17050201
Size	99,806 acres
§303(d) Listed Stream Segments	Dennett Creek, Hog Creek, Scott Creek, Warm Springs Creek
Beneficial Uses Affected	Cold water aquatic life, primary and secondary contact recreation, agricultural and industrial water supply, wildlife habitat, aesthetics
Pollutants of Concern	Sediment, nutrients, temperature, flow alteration
Major Land Uses	Agriculture, forest, urban/suburban
Date Approved by U.S. EPA	November 2003

Overview

The Brownlee Reservoir (Weiser Flat) Subbasin encompasses the area draining into the Snake River downstream of the Weiser River inflow and upstream of Brownlee Reservoir. This subbasin is located along the central portion of the Idaho-Oregon border in southwest Idaho. The headwaters for these creeks originate in extreme western Idaho in the Hitt Mountains.

Within the subbasin, there are five water quality limited streams, four of which were placed on the Idaho 1998 §303(d) list and one of which (Jenkins Creek) was removed from the list in 1998, but recent monitoring has identified water quality concerns below the original assessment site that necessitate re- listing.

There are clear indications that recreational beneficial uses are not fully supported for the Hog, Scott, Warm Springs, and Jenkins Creeks subwatersheds. However, the available information for cold water aquatic life uses is limited. Support of cold water aquatic life uses cannot be determined specific to nutrient and sediment concentrations due to a lack of aquatic life data. Interpretation of data available for nutrients and sediments is therefore tied to the attainment of full support of downstream waters (Snake River-Hells Canyon TMDL) shown to be impaired due to excessive nutrient and sediment loading. Secondary contact recreation is not supported in Hog, Scott, Warm Springs, or Jenkins Creeks due to exceedances of bacteria standards during the spring and summer months. All listed water bodies exhibit monitored concentrations of total phosphorus that are above the target identified to improve water quality in the Hells Canyon reach of the Snake River.

Bacteria is proposed to be listed for Hog, Scott, Warm Springs, and Jenkins Creeks as a §303(d) pollutant as part of the first §303(d) list submitted by the state of Idaho subsequent to the approval of this TMDL.

Streams and Pollutants for Which TMDLs Were Developed

Dennett Creek: Sediment
Hog Creek: Nutrients
Scott Creek: Nutrients, sediment
Warm Springs Creek: Nutrients, sediment
Jenkins Creek: Nutrients, sediment

Subbasin Documents

Total Maximum Daily Loads (TMDL) for the Brownlee Reservoir (Weiser Flat) Subbasin (July 2003)
Weiser Flat TMDL Implementation Plan for Agriculture (September 2004)

Department of
Environmental Quality

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