Clean Water Services: Revised Temperature Management Plan


The Tualatin River Watershed faces water quality management challenges that reflect a complex web of land uses, pollution sources and management agencies.

After an investment of several hundred million dollars during the 1990’s, the wastewater treatment facilities operated by Clean Water Services are now considered state-of-the-art, and treat wastewater to some of the highest levels in the nation. They also have an exemplary record of compliance with regulatory permits. This has resulted in significant water quality improvements in the mainstem Tualatin River. Despite these achievements, much work to improve watershed health remains to be done. The Tualatin River and most of its tributaries have been designated water quality limited under Section 303(d) of the Clean Water Act.

Traditional water quality regulation has relied on regulating discreet, easily identifiable pollution sources, such as industrial facilities or sewage treatment plants. While this approach has resulted in significant water quality improvements, it has not addressed diffuse sources, such as runoff from farms, lawns, working forests, roads and parking lots, which are a major cause of water pollution. The traditional approach has also failed to foster sufficient coordination among water quality management agencies. This has resulted in solutions that have limited scope and effectiveness.

The use of flow augmentation and shade to meet temperature requirements will eliminate the need for more burdensome alternatives, such as the installation of refrigeration equipment at wastewater treatment facilities, or piping treatment facility effluent to another river basin. Either of these options would be very expensive. Moreover, they would contribute to other environmental problems. Shade, on the other hand, costs several times less and benefits the environment in a number of ways, including providing species habitat, reducing flooding and erosion, and keeping sediments and other pollutants out of streams.

Revised Temperature Water Plan, cut from document

Click the icon below to access a copy of the impressive plan that served as a foundation for a ground-breaking approach to improving the health of the Tualatin River Watershed: