Tualatin Basin Water Supply Project

Expanding Water Services


As communities in the Tualatin Basin continue to grow, more water is needed for municipal drinking water and industrial uses. In addition, more water is needed to augment flow in the Tualatin River and its tributaries for water quality. In 2001, water resource agencies in the Tualatin Basin formed a partnership to study and decide how to best serve the water needs of the future. Beaverton has financially participated in the Tualatin Basin Water Supply Project (TBWSP) feasibility work since signing an agreement in 2001 with the other project partners.
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The TBWSP involves:
  • A large pumping station located below the dam to pump water from the Tualatin River into the lake during the winter
  • Construction of a large pipeline from the dam to the Joint Water Commission (JWC) Water Treatment Plant
  • Expansion of the JWC Water Treatment Plant south of Forest Grove
  • Raising the height of Scoggins Dam (which forms Hagg Lake)
Scoggins Dam and Hagg Lake are owned by the U.S. Bureau of Reclamation (USBR), which built the facility in 1970. The TBWSP will add approximately 53,000 acre-feet of water to Scoggins Reservoir (Hagg Lake) per year (one acre-foot is the amount of water it takes to fill an acre of area with one foot of water). The City of Beaverton is a partner and has a 3.8% interest in the project to eventually own an additional 2,000 acre-feet (0.65 billion gallons). The City currently has a contract with the USBR that gives the City a right to use up to 4,000 acre-feet each year (1.3 billion gallons).

Project Partners


The TBWSP is a collaborative effort. Besides providing additional supply for municipal water needs, the project will provide environmental benefits and a stable water supply for agricultural uses. Clean Water Services is the lead agency for the project, providing project management and public involvement. Project partners include:


Additional Resources