Water Quality Improvement Projects (TMDLs) > Yakima Watershed Area Projects > Teanaway River Temperature Project

Water Quality Improvement Project
Teanaway River:
Temperature

Introduction

The Teanaway River Basin drains an area of 207 square miles and is located east of the Cascade crest near the town of Cle Elum, Washington. The Teanaway lies in the upper reaches of the larger Yakima River watershed. The climate consists of warm, dry summers and cold, snowy winters. Annual precipitation ranges from 20 inches near the mouth of the Teanaway River (elevation 1800 feet) to 90 inches in the high mountains (elevation 6000 feet).

Water quality issues

In 1998, the Department of Ecology conducted stream temperature studies at eight sites in the Teanaway Basin. The resulting Teanaway River Basin Temperature Pilot Technical Assessment identifies increased temperatures as the impairing pollutant to the Teanaway River system.

Why this matters

Water temperature influences what types of organisms can live in a waterbody. 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.

What are the main factors that affect stream temperature?

• Riparian shade - intercepts incoming solar radiation.
• Channel width:depth - greater width exposes more of stream to solar radiation; affected by sediment load and stream bank stability.
• Stream flow - higher flow increases velocity and depth, decreases time and proportion water exposed to solar radiation.

What can be done to reduce stream temperatures?

Studies have shown that lack of riparian shade, excessive sediment load, and low stream flow can increase stream temperature. Land management activities, such as forest management, grazing, agriculture, and development may affect temperature adversely where they damage vegetation adjacent to streams, cause excessive erosion of stream banks, add sediment to streams, reduce instream flow, or return warmed waters to the stream. Activities that reduce stream temperatures may include those that provide more shading, increase stream flows, and reduce sedimentation.

What we found in the Teanaway River system regarding stream temperatures

The Teanaway River system represents some of the highest quality streams and cold-water fish spawning and rearing areas in the Yakima River Basin. In the summer, maximum daily water temperatures in the Teanaway river system range from 12^o C (54^oF) near the headwaters to 26^o C (79^o F) near the mouth.

Under state standards, temperatures should not exceed 16^o C (61^o F) in the upper reaches and 18^o C (64^o F) in the lower reaches of the river. When natural conditions exceed these numeric standards, human activities are not to increase stream temperatures by more than 0.3^o C. Data collected during the summer of 1998 show that, except near the headwaters, temperatures throughout the basin exceeded state water quality standards. Summer temperatures in the lower basin exceeded the numeric standard more than 75% of the time.

Status of the project

EPA approved the TMDL submittal in January 2002.  The submittal contained technical studies, identified implementation measures and monitoring plan.

Ecology, along with a work group made up of local groups and the public, developed a water quality implementation plan, also known as a detailed implementation plan.  The plan included a strategy on how, when and where restoration activities will be implemented to improve stream temperatures.  The workgroup:

• Evaluated technical studies and potential implementation measures.
• Prioritized any additional studies and implementation measures.
• Coordinated implementation of selected measures.
• Developed a monitoring plan to measure improvement.

Technical information

Teanaway Temperature Total Maximum Daily Load Submittal Report
www.ecy.wa.gov/biblio/0110019.html

Teanaway Temperature Total Maximum Daily Load: Detailed Implementation Plan
www.ecy.wa.gov/biblio/0310025.html

Teanaway River Basin Temperature Pilot Technical Assessment
www.ecy.wa.gov/biblio/0003015.html

Related information

Focus on Teanaway Basin - A plan to improve stream temperatures
www.ecy.wa.gov/biblio/0110020.html

WRIA 39: Upper Yakima Watershed Information (Environmental Assessment Program web site)
www.ecy.wa.gov/apps/watersheds/wriapages/39.html

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