Background on the NW Temperature Criteria Project
Cold, clean water is critical to the protection of threatened and endangered salmon, steelhead, bull trout and cutthroat trout (a group referred to as salmonids). These fish need cold water throughout their various life stages. The appropriate water temperature is a critical part of habitat needed by salmon. Temperature in rivers and streams varies with the seasons, over the course of 24 hours and over the length of a river. A water quality standard for temperature is key to ensuring rivers and streams are cold enough to support these fish.
In 1996, Oregon revised their water temperature standard and submitted it to EPA for approval. EPA approved Oregon’s standard in 1999, but during the review process concerns were raised by EPA, the National Marine Fisheries Service and others that the standard would not fully protect all life stages of threatened and endangered salmonids. To address these concerns, EPA Region 10 started a project to develop regional temperature criteria guidance that would be protective of salmonids. States and tribes in the Pacific Northwest could then use this guidance when developing their temperature standards, as required by the Clean Water Act.
This project is unique because it is a collaborative process between states, tribes and federal agencies. The guidance will supplement the national water quality criteria for temperature to meet the specific needs of salmonids in Northwest streams and rivers.
The temperature criteria guidance will be used by:
Who is involved in the project?
Washington Department of Ecology, Idaho Department of Environmental Quality, Oregon Department of Environmental Quality, National Marine Fisheries Service, U.S. Fish and Wildlife Service, and representatives of Pacific Northwest Tribes are all joining EPA in this effort.
There are two workgroups supporting this project. The Technical workgroup is made up of scientists from various federal, state and tribal organizations who will be responsible for developing and recommending the regional temperature criteria guidance. As part of their work, they will be examining:
- states and tribes in the Northwest to develop or revise water quality standards for temperature.
- EPA Region 10 to review and approve or disapprove state and tribal water quality standards for temperature.
The Policy workgroup is made up of state, federal and tribal members who will assist EPA Region 10 in reviewing and finalizing the regional temperature criteria guidance. Some of the issues that the policy group will be considering are:
- the most recent science on how temperature affects salmonid physiology and behavior,
- the combined effects of temperature and other stressors on threatened fish stocks,
- the pattern of temperature fluctuations in the natural environment, and
- other relevant issues
- how to make the guidance practical and
- it’s compliance with the Clean Water Act and the Endangered Species Act.