Publication Summary

This TMDL covers the Upper White River watershed. For the purposes of this TMDL we identify the beginning of this watershed as the confluence of the Greenwater River with the White River. It includes the major tributary subwatersheds of the Greenwater River, West Fork White and Huckleberry Creek.

This TMDL covers the Upper White River watershed. For the purposes of this TMDL we identify the beginning of this watershed as the confluence of the Greenwater River with the White River. It includes the major tributary subwatersheds of the Greenwater River, West Fork White and Huckleberry Creek.

This TMDL study specifically addresses chronically elevated water temperatures observed in the lower and mid-reaches of the Greenwater River. Water temperature has been observed to exceed the state water quality standard at several monitoring locations on the Greenwater River (river mile 2.2, 8.5, and 11.0), which led to its inclusion on Washington?s 1996 and 1998 303(d) lists (water body identification number WA-10- 1046). The state temperature standard that applies to the Greenwater River, a Class AA water, is 16 C (60.8 F).

In addition, recent water quality monitoring covering temperature, sediment, and habitat within the Upper White River watershed indicates that the introduction of elevated levels of sediments to specific reaches within the Upper White River watershed has resulted in physical impairments to aquatic habitat and increased vulnerability to heating. State standards that apply to the Upper White River watershed include narrative standards for beneficial use of wildlife habitat, and for protection from deleterious substances. Based on this, the TMDL study included sediment within its scope. The TMDL addresses the watershed processes responsible for temperature and sediment impairments throughout the Upper White watershed. As such, this TMDL will also provide for the restoration of aquatic habitat forming processes, and therefore habitat impairments as well.