Visit Ecology's TMDL webpage | Read EPA's 2020 TMDL | Read Ecology's Implementation Plan Blog

The Columbia and Lower Snake rivers are listed on the state's polluted waters list for high water temperatures that are above Washington water quality standards and can harm salmon. Because the Columbia and Lower Snake rivers cross multiple state boundaries and span almost 900 miles, the EPA published the Total Maximum Daily Load (TMDL) for temperature in the Columbia and Lower Snake rivers on May 20, 2020.

We are currently in the early stages of developing an implementation plan for this TMDL. This plan will describe our strategy for meeting temperature standards and how we will partner and work together with temperatures sources to address their impacts in the Columbia and Lower Snake rivers. It will include our strategies to address key temperatures sources throughout the rivers, including our processes for working with dams, updating permits for point sources, and prioritizing tributary work to address high river temperatures and to protect salmon. 

Get involved

Public Input Survey

We launched a public survey from July 14 - Dec. 31, 2025, to allow partners and the public share input to inform our work as we develop the implementation plan. The survey is now closed. Input we recieved can be viewed online. 

Advisory Committee Meetings

Advisory committee meetings help inform our efforts as we begin the effort to develop a draft implementation plan. Topics for meetings vary, though agendas support our goal of identifying collaborative strategies to address sources of temperature pollution. See past meeting materials. 

Upcoming Advisory Committee Meetings 

We held our last scheduled Advisory Committee meeting on January 26, 2026. Meeting agenda and slides are available below. 

We are now working on developing a draft implementation plan. Thank you to committee members and members of the public for your participation in past meetings. Future meetings will be determined as this work continues. 

Join Ecology’s water quality improvement email list for updates on our work. 

 Past Advisory Committee Meetings

January 26, 2026

• Meeting Agenda 
• Water Quality Attainment Plan (WQAP) updates & Ecology's system-wide modeling project

December 6, 2025 

• Meeting agenda
• Dam allocations overview 
• Water Quality Attainment Plans (WQAPs)

September 29, 2025

• Meeting agenda 
• Presentation - Point Source Overview
• Resource - Accessing and Tracking Reserve Capacity and WLAs in the Columbia and Lower Snake River TMDL for Temperature (EPA)

August 26, 2025

• Meeting Agenda
• Presentations
  • Nonpoint Program Overview 
  • Nonpoint & Implementation Plan

July 28, 2025

• Meeting agenda. 
• Presentations
  • Introduction - tributaries and the TMDL 
  • Souhwest Region Office work 
  • Central Region Office work 
  • Eastern Region Office work

June 17, 2025 

• Meeting agenda
• Presentation - Advisory Group & Implementation Plan

March 17, 2025 

• Meeting agenda 
• Presentations: 
  • Ecology's TMDL Implementation Plan overview
  • Environmental Protection Agency (EPA) TMDL overview