|Hydrologic Unit Codes||17060302|
|Size||1,910 square miles (1,222,400 acres)|
|Beneficial Uses Affected||Cold water aquatic life, salmonid spawning, primary and secondary contact recretion|
|Major Land Uses||Timber, grazing, mining, recreation|
|Date Approved by EPA||Subbasin assessment only; not subject to EPA approval|
The Lower Selway River subbasin is approximately 1,910 square miles of predominantly undeveloped forestland and free-flowing streams. The Selway River is designated as a Wild and Scenic River and most of the subbasin upstream of Selway Falls is part of the Selway-Bitterroot Wilderness Area. Selway Falls, at 1,730 feet elevation, is a barrier that separates the 166 square miles of the Lower Selway River subbasin from the upper areas.
2000 Subbasin Assessment
All the stream segments that are assessed in this document are in this lower subbasin. The streams in the subbasin are home to Chinook and Coho Salmon, steelhead, Bull Trout, Rainbow Trout, Westslope Cutthroat Trout, Mountain Whitefish, Brook Trout, and many nongame species. Most of the land in the subbasin is public land owned by the United States and managed by the Nez Perce National Forest. Several parcels along the lower Selway River corridor deeded under the Homestead Act are in private hands with management easements under the Wild and Scenic Rivers Act.
Due to sediment concerns, 15 tributary stream segments were placed on the 1996 §303(d) list. Idaho has a narrative sediment standard that says sediment concentrations shall not impair beneficial uses, which for these streams are cold water biota and salmonid spawning. Available data show that sedimentation in the subbasin streams is within the normal variability that would be expected here.
The 15 stream segments in the subbasin were added to the §303(d) list because they did not meet a US Forest Service management goal called a “Desired Future Condition,” not because their water quality failed to support their designated beneficial uses and exceeded the water quality criterion.
DEQ investigated the ability of the 15 tributary streams to support their designated beneficial uses. This investigation showed that all 15 tributaries were supporting their designated beneficial uses.
2000 Summary of Assessment Outcomes
The following are the recommendations of this subbasin assessment:
The 15 stream segments listed for sediment on the 1996 §303(d) list should be delisted.
Work under Clean Water Act Section 303(d) should stop on the Lower Selway River subbasin streams with this assessment.
Management agency and landowner resources in the subbasin should continue to be applied to projects to reduce legacy impacts. These activities can continue to enhance water quality in the subbasin.
This information was presented to the Clearwater Basin Advisory Group on March 2, 2000. The Clearwater Basin Advisory Group voted unanimously to concur with DEQ’s recommendations.
- Lower Selway River Subbasin Assessment (December 2000)