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Boise River (North/Middle Fork) Subbasin

Data Details
Hydrologic Unit Codes 17050111
Size 759 square miles (486,036 acres)
Beneficial Uses Affected Cold water aquatic life, salmonid spawning, primary and secondary contact recreation, domestic water supply
Major Land Uses Forestry, roads, mining, agriculture/livestock, recreation
Date Approved by EPA Subbasin assessment only; not subject to EPA approval

Subbasin Characteristics

The North/Middle Fork Boise River subbasin is located in southwestern Idaho between Boise and Stanley. The subbasin includes the North and Middle Fork Boise River and all tributaries upstream from the confluence of the North and Middle Forks of the Boise River. The subbasin area is primarily federally owned and administered. Atlanta is the only recognized community in the watershed with year-round residents. Access is provided primarily by US Forest Service-maintained roads and by county-owned or county-maintained roads.

2002 Upper Boise River Watershed Assessment

The upper Boise River watershed is made up of two subbasins, as summarized in the table below.

DataDetails
Hydrologic Unit Codes17050111 (North/Middle Fork Boise River Subbasin)
17050113 (South Fork Boise River Subbasin)
Size2,033 square miles (1,301,120 acres)
Beneficial Uses Affected

Cold water aquatic life, salmonid spawning, primary and secondary contact recreation, domestic water supply

Major Land UsesForestry, roads, mining, agriculture/livestock, recreation

Located in southwestern Idaho, the upper Boise River watershed is about 2,033 square miles of predominantly undeveloped forestland and open range with both managed and free-flowing streams. The upper Boise River watershed is comprised of the two hydrologic cataloging units of the Boise River system upstream of Arrowrock Reservoir. The waters of the subbasin join to form the Arrowrock Reservoir, which supplies water to Lucky Peak Reservoir and the lower Boise River.

This subbasin assessment found that all § 303(d)-listed water bodies within the upper Boise River watershed are currently fully supporting all of their beneficial uses and are no longer candidates for TMDL development.

The subbasin assessment also lists water bodies not fully supporting their beneficial uses that should be added to the § 303(d) list during the next listing cycle.

2002 Summary of Assessment Outcomes On 1998 § 303(d) List

StreamDetails
Buck CreekDelist; no TMDL needed
Willow CreekDelist; no TMDL needed
South Fork Boise RiverDelist; no TMDL needed
Deer CreekDelist; no TMDL needed
Little Smoky CreekDelist; no TMDL needed
Cayuse CreekDelist; no TMDL needed
North Fork Feather CreekDelist; no TMDL needed
Smith CreekDelist; no TMDL needed
Rattlesnake CreekDelist; no TMDL needed
Not on 1998 § 303(d) List 
Crooked RiverAdd to § 303(d) list for sediment
Beaver CreekAdd to § 303(d) list for sediment
Rabbit CreekAdd to § 303(d) list for unknown pollutant
Meadow CreekAdd to § 303(d) list for sediment
French CreekAdd to § 303(d) list for sediment
Little Camas ReservoirAdd to § 303(d) list for sediment

Subbasin Documents

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DEQ Boise Regional Office
1445 N. Orchard St.
Boise, ID 83706
Ph: (208) 373-0550
Fax: (208) 373-0287
Toll Free: (888) 800-3480

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