Protecting Public Health and the Environment.

Clearwater River, South Fork Subbasin

Subbasin at a Glance

Hydrologic Unit Codes 17060305
Size 1,175 square miles (752,000 acres)
§303(d) Listed Stream Segments South Fork Clearwater River, Threemile Creek, Butcher Creek, Dawson Creek, Little Elk Creek, Big Elk Creek, Buffalo Gulch, Newsome Creek, Nugget Creek, Beaver Creek, Sing Lee Creek, Cougar Creek, Lucas Lake
Beneficial Uses Affected Cold water aquatic life, salmonid spawning, primary and secondary contact recreation, special resource water
Pollutants of Concern Bacteria, dissolved oxygen, flow alteration, habitat alteration, ammonia, nutrients, sediment, temperature
Major Land Uses Timber harvesting, mining, grazing, outfitting and guiding, recreation, agriculture
Date Approved by U.S. EPA March 2004

Overview

The South Fork Clearwater River lies entirely within Idaho County, Idaho, and partially on the Nez Perce Reservation. Eighteen stream segments and one lake in the South Fork Clearwater River Subbasin were listed on the 1998 §303(d) list. TMDLs were completed in 2000 for six stream segments in the Cottonwood Creek watershed within the South Fork Clearwater River Subbasin. This document addresses the remaining 12 listed streams and Lucas Lake.

Water temperatures are elevated above water quality standards at all monitoring locations throughout the subbasin. Logging, roading, mining, grazing, and agricultural activities have reduced shading of surface water. Point source contributions to water temperature increases are minor except for the effects of the effluent from the Grangeville wastewater treatment plant.

At the completion of the assessment of temperature, it was concluded that many unlisted stream segments throughout the subbasin need heat load reductions to meet water quality standards as well. Therefore, temperature TMDLs were established for an additional 58 unlisted stream segments throughout the subbasin.

Coarse sediment, which effects salmonid spawning, has degraded water quality in the upper basin. Nonpoint sediment sources in the South Fork Clearwater River are mainly agricultural and grazing areas (10 – 30 times natural background) and forested areas (2 times natural background). Point sources of sediment include five municipal wastewater treatment plants, suction dredge mining, and construction and industrial storm water runoff.

Bacteria and nutrients in Threemile Creek greatly exceed state standards and U.S. Environmental Protection Agency guidelines. The majority of the bacteria are thought to be from livestock grazing; the majority of the nutrients are from the Grangeville wastewater treatment plant.

It is recommended that Lucas Lake and seven streams listed as impaired by sediment and one stream segment each listed as impaired by bacteria, nutrients, ammonia, and a lack of dissolved oxygen be removed from the §303(d) list.

Streams and Pollutants for Which TMDLs Were Developed

S. Fork Clearwater River
Temperature, sediment
Threemile Creek
Temperature, bacteria, nutrients, dissolved oxygen, sediment
Butcher Creek
Temperature, sediment
Dawson Creek
Temperature
Little Elk Creek
Temperature
Big Elk Creek
Temperature
Buffalo Gulch
Temperature
Newsome Creek
Temperature
Beaver Creek
Temperature
Nugget Creek
Temperature
Sing Lee Creek
Temperature
Cougar Creek
Temperature
58 Other Water Bodies
Temperature

Subbasin Documents