Water Quality Improvement Project
Naches River Area:


The Naches River watershed, located in part of the Yakima River drainage basin, flows from the Cascade mountains to the city of Yakima. It then merges with the Yakima River. Some of the river's tributaries of interest include the American River; Bear Creek; Blowout Creek; Bumping River; Cowiche Creek; Crow Creek; Gold Creek; Little Naches River; Little Rattlesnake Creek; Mathew Creek; Nile Creek; Rattlesnake Creek; and Reynolds Creek. (Study area map)

The climate in the Naches River watershed is generally cool and moist in the mountainous portion, and warm and dry in the valley. Precipitation ranges from 80 - 140 inches in the mountains to less than 10 inches in the valley portion. The Naches River is used as core summer habitat and spawning by a number of species, including Spring Chinook salmon, rainbow/steelhead trout, and bull trout.

Water quality issues

Studies determined that the Naches River does not meet state water quality standards for temperature in a number of places. The Naches River, along with a number of tributaries, was listed on the 2004 and 2008 water quality assessments in category 5 (also known as the 303[d] list), for streams that are impaired because the water is too hot, for bulltrout spawning and rearing; core summer salmonid habitat; and salmonid spawning, rearing, and migration.

Naches River at Eschbach, Washington State.  Photo courtesy of Laine Young, WA Department of Ecology

Why this matters

Water temperature influences what types of organisms can live in a water body. Cooler water can hold more dissolved oxygen that fish and other aquatic life need to breathe. Warmer water holds less dissolved oxygen. Threatened and endangered salmon need cold, clean water to survive.

The watershed community can cool water temperatures by shading the water with streamside vegetation. Land use practices that reduce or slow water runoff can also help water temperatures by stabilizing water flow in the river system.

Status of the project

In 2008 Ecology completed the technical study of Naches River and tributaries. Ecology and interested citizens in the watershed then developed a draft implementation strategy, which was available for public review and comment from October 20 - November 19, 2010. No public comments were received.

Ecology sent the finalized total maximum daily load (TMDL), which was published as Volume 1: Water Quality Study Findings. Volume 1 recommended specific actions for reducing water temperatures, and was approved by the federal Environmental Protection Agency (EPA). The study, combined with the implementation strategy published as Volume 2, constitutes the water quality improvement report (WQIR) for the Upper Naches River and Cowiche Creek for temperature. In addition to the Upper Naches and Cowiche Creek Temperature WQIR, a project will be developed for reducing temperatures in the Tieton River and Naches Mainstem Basin.

Now that EPA has approved the WQIR, Ecology is working with interested citizens in the watershed on implementing actions. When water quality improvement plans are completed for all the reaches in the Naches watershed, it is anticipated that temperatures in Tieton and Naches Rivers and Cowiche Creek will come into compliance with the state water quality standards.

South Fork Cowiche River at Refugia Cool Alcove photo, Washington State.  Photo courtesy of Laine Young, WA Department of Ecology

Technical information

Unless otherwise specified, the following documents are Ecology publications.

Quality Assurance Project Plan: Naches River Temperature Total Maximum Daily Load

Upper Naches River Temperature Total Maximum Daily Load: Volume 1: Water Quality Study Findings

Upper Naches River and Cowiche Creek Temperature Total Maximum Daily Load: Volume 2: Implementation Strategy

Quality Assurance Project Plan: Cowiche Creek Vegetation and Shade Study

Related information

Wenatchee National Forest Water Temperature Total Maximum Daily Load: Technical Report (Ecology publication)

WRIA 38: Naches Watershed Information (Environmental Assessment Program web site)


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Last updated June 2015


WRIA: #38 (Naches)

Waterbody Names:
Naches River
Selected tributaries


# of TMDLs: 17

Approved by EPA; has implementation strategy

Contact Info:
Laine Young
Phone: 509-575-2642
Email: Laine.Young@ecy.wa.gov

Central Region
1250 West Alder Street
Union Gap, WA 98903-0009