Washington State Department of Ecology

Ecology home > Water Quality > Water Quality Assessments & TMDLs > TMDLs > Overview

Mouth of the Wenatchee River as it enters the Columbia River. Photo courtesy of Bryan Neet, Dept. of Ecology.

Overview

The Total Maximum Daily Load (TMDL) or Water Quality Improvement Project process was established by Section 303(d) of the Clean Water Act (CWA). Federal law requires states to identify sources of pollution in waters that fail to meet state water quality standards, and to develop Water Quality Improvement Reports to address those pollutants. The Water Quality Improvement Project (TMDL) establishes limits on pollutants that can be discharged to the waterbody and still allow state standards to be met.

In January 1998, the Washington Department of Ecology (Ecology), U.S. Environmental Protection Agency (EPA), Northwest Environmental Advocates, and Northwest Environmental Defense Center agreed to a clean up schedule directing how Washington state will improve the health of nearly 700 water segments. Ecology's Memorandum of Agreement (MOA) (PDF) outlines a plan and schedule to improve polluted waters while expanding public involvement in Water Quality Improvement Reports.

General information about TMDLs:

Water Cleanup Plans - Total Maximum Daily Loads (Ecology publication)
Fact sheet on the TMDL program.
Water Quality Improvement Projects also known as Total Maximum Daily Loads (TMDLs): What should I know? What does it mean to me? (Ecology publication)
This publication provides discusses of water quality improvement projects (TMDLs) and the water quality planning process, what it means to you, and how you can become part of the solution.
"TMDLS: How? What? Why?" (PDF)
(Also available as a PowerPoint presentation [~2.4 mb])
Presentation outlining how the TMDL process works.
"Protecting Washington State's Waters" (Ecology video)
This video describes, through interviews and photos, the process the Department of Ecology uses to improve water quality in Washington State's rivers, lakes and streams.
Frequently Asked Questions About TMDLs (Ecology publication)
Questions and answers to frequently asked questions about total maximum daily loads (TMDLs).
Watershed Approach to TMDL Development
www.ecy.wa.gov/programs/wq/watershed/overview.html
Describes Water Quality Improvement work using a watershed approach

See the Related page for more information.

Last updated May 2006