TMDL implementation kickoff meeting

In our upcoming meeting, we will provide an overview of the history of this work, outline our strategies for developing an implementation plan. We will have time for questions and answers during the meeting.

In 2021, the U.S. Environmental Protection Agency (EPA) reissued a temperature Total Maximum Daily Load (TMDL) for the Columbia and Lower Snake Rivers and Ecology is developing the implementation plan. A TMDL is a water quality improvement project which sets a plan for each water body on the state's polluted waters list.

• Visit Ecology’s Columbia and Lower Snake rivers temperature TMDL webpage
• Learn more about this TMDL on our blog post

The Columbia and Lower Snake Rivers are included on Washington's 303(d) list as impaired due to high water temperatures, which pose a threat to the salmon and steelhead populations that rely on the rivers for migration and spawning. Among several contributing factors, the TMDL states that the two dominant sources of increased temperatures in the Columbia and Snake systems are dams and climate change.

Background

The federal Clean Water Act requires states to develop a Total Maximum Daily Load (TMDL) — or water quality improvement project — plan for each water body on the state's polluted waters list, also known as the 303(d) list. This science-based approach assigns a numerical value that represents the highest amount of a pollutant a surface water body can receive and still meet the water quality standards. Learn more about the TMDL process.