Did you know that warm water is the most common reason why water bodies don't meet Water Quality Standards throughout the Northwest?

Of the water bodies listed as "impaired" in Washington, Oregon, Idaho and Alaska, 29% had this designation because of warm water temperatures. These waters are placed on the 303(d) list and trigger the TMDL process. To learn about what 303(d) listing means and the TMDL process, click on the TMDL Links icon below.

Of the 600 waters on the 303 (d) list in Washington, about 300 were listed for temperature. The length of the Columbia from Canada to the ocean is on this list.