Section 303 of the Clean Water Act (CWA) requires States to adopt Water Quality Standards (WQS) to restore and maintain the chemical, physical, and biological integrity of the Nation's waters. WQS consists of beneficial uses (i.e. salmonid fish spawning, resident fish and aquatic life) designated for specific waterbodies and water quality criteria to protect the uses. States have primary responsibility for developing appropriate beneficial uses for waterbodies in their State. States review, and it appropriate, revise their water quality standards on a triennial basis in accordance with CWA 303(c). Also under CWA 303(c), EPA must review and approve or disapprove any revised or new standards. If EPA disapproves any portion of the state standards the state has 90 days to adopt the changes specified by EPA, after which time EPA must propose and promulgate such standards. The purpose of this Biological Assessment is to assess the potential effects of EPA's proposed approval of Oregon's revised dissolved oxygen (DO), temperature and pH criteria on species listed under the Endangered Species Act (ESA).

"{Prepared} for the U.S. Fish and Wildlife Service and the National Marine Fisheries Service." "September 15, 1998." Includes bibliographical references.