Protecting Public Health and the Environment.

Clearwater River, North Fork (Lower) Subbasin

Subbasin at a Glance

Hydrologic Unit Code 17060308
Size 1,145 square miles (732,800 acres)

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

Alder Creek, Beaver Creek, Bingo Creek, Breakfast Creek, Cedar Creek, Cranberry Creek, Deep Creek, Elk Creek, Elkberry Creek, Floodwood Creek, Gold Creek, Isabella Creek, Long Meadow Creek, Meadow Creek, Middle Fork Robinson Creek, Oviatt Creek and tributaries, Partridge Creek, Reeds Creek, Round Meadow Creek, Stony Creek, Swamp Creek, Three Bear Creek

Beneficial Uses Affected Salmonid spawning, cold water aquatic life, primary and secondary contact recreation
Major Land Uses Forestry, recreation, grazing
Date Approved by EPA January 2003
Approval Letter
Date Addendum Approved by EPA November 2013
Approval Letter

Subbasin Characteristics

The Lower North Fork Clearwater River subbasin is located in north-central Idaho, primarily in Clearwater County. Situated around Dworshak Reservoir, all streams flow directly or indirectly into the reservoir. Dworshak Dam was completed in 1971, and the reservoir attained full pool two years later. At full pool, the reservoir is 54 miles long, 2 miles across, and has a maximum depth of 480 feet. Dworshak Dam provides no passage for migrating fish.

Over the past 100 years, human activities, primarily silvicultural, have changed the landscape of the subbasin, and these alterations are the primary reason TMDLs were developed for the Lower North Fork Clearwater River subbasin.

2002 Subbasin Assessment and TMDL

Twelve TMDLs were written for seven water bodies for three separate pollutants. Seven water bodies were recommended for future §303(d) listing for temperature. The pollutants in the subbasin are mainly from nonpoint sources, as the only point source is the wastewater treatment plant in Elk River. For sediment, the main sources are from natural background contributions, roads, mass failures, and streambank and riparian area erosion. For bacteria, the main sources are cattle and other livestock, wildlife, and humans. For temperature, the source is solar radiation (due to lack of shade).

Nutrients and dissolved oxygen were listed as pollutants of concern on the 1998 §303(d) list; however, after analyzing the data, these pollutants were determined to not be impairing any beneficial uses.

2002 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Breakfast Creek
Sediments
Cranberry Creek
Sediment, temperature, bacteria
Elk Creek (Lower)
Temperature
Long Meadow Creek
Sediment, temperature, bacteria
Partridge Creek
Sediment
Reeds Creek
Sediment
Swamp Creek
Sediment, temperature

2013 Addendum

This document presents a five-year review of the original subbasin assessment and TMDL and an addendum addressing temperature-impaired water bodies in the subbasin. Based on the 2002 TMDL, 25 assessment units (AUs) were added to Category 5 of the 2010 Integrated Report for temperature violations. This addendum establishes temperature TMDLs for these assessment units based on the concept of maximum shading under potential natural vegetation resulting in natural background temperature levels.

2013 Addendum: Streams and Pollutants for Which TMDLs Were Developed

Elkberry Creek
Temperature
Middle Fork Robinson Creek
Temperature
Gold Creek, Meadow Creek, and tributaries
Temperature
Reeds Creek and tributaries
Temperature
Alder Creek
Temperature
Beaver Creek
Temperature
Bingo Creek
Temperature
Beaver Creek tributaries
Temperature
Isabella Creek
Temperature
Stony Creek and tributaries
Temperature
Floodwood Creek and tributaries
Temperature
Breakfast Creek
Temperature

Subbasin Documents


Staff Contacts

Surface Water Quality Manager
Sujata Connell
DEQ Lewiston Regional Office
1118 "F" St.
Lewiston, ID 83501
(208) 799-4370
sujata.connell@deq.idaho.gov

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