WATER SUPPLY/City gets new water source and protects salmon
Recent growth in the Pacific Northwest cities of Seattle; Portland, Ore.; and Tacoma, Wash., is threatening the region’s water supply. Tacoma is currently building a $250 million pipeline to serve the area’s growing population. However, the project’s potential impact on salmon habitat created concerns for the city officials spearheading the project. Tacoma’s primary water source is the Green River. In the 1960s, the city anticipated the need for more water, and officials acquired right-of-way, applied for water rights and made plans for the construction of a second supply.
In 1986, Tacoma’s right to take an additional 100 cubic feet per second of water from the Green River was upheld in the Washington Supreme Court. And, in 1988, Tacoma signed a contract with HDR Engineering, Omaha, Neb., to secure permits and permissions necessary for the design, construction and operation of the Second Supply Project.
Since then, engineers, scientists and planners have secured more than 60 permits needed to build the 34-mile-long pipeline. They had to develop designs that would be sensitive to the environment and find ways to address the sometimes conflicting interests of Native American tribes, whitewater enthusiasts, fishermen and regulatory agencies.
The project consists of a 48- to 80-inch diameter steel pipeline that crosses 20 rivers and streams, 56 wetlands, 36 roads, 16 railroad tracks, a major regional shopping mall, a golf course and two interstate highways. With the extensive environmental analysis and design already accomplished for the project, workers began construction on the lower eight miles in June 1999, taking precautions to avoid disrupting the salmon by: * constructing new fishscreens, fish passage and fish restoration facilities to help re-establish salmon upstream of Tacoma’s diversion dam, presently a total barrier to upstream migrating salmon; * creating new spawning, rearing and refuge habitat for salmon as mitigation for increasing water supply storage in the Howard Hanson Dam; * employing 500- and 400-foot long microtunnel crossings of the Puyallup and Green rivers to avoid building directly in fishing waters.
Construction of the lower third of the pipeline was completed in January, and design and construction of the balance of the project will be completed by 2005. “Successful completion of the Second Supply Project will be an historic milestone for the Puget Sound region,” says Tacoma Waters Project Manager Craig Gibson. “The project will form the backbone of an interconnected, regional water supply system capable of achieving the optimal use of the region’s precious water resources while enhancing the environment for the benefit of fish and wildlife.”