OregonLive.com—The Tualatin Valley Water District voted 4-0 Wednesday to tap the Willamette River as the district’s need for water grows in the next 30 years and beyond.

The district will partner with Hillsboro, which voted in February to adopt the same long-term strategy for water supply.

The two agencies plan to build a water treatment plant in Wilsonville and a pipeline to transport the water to Washington County.

The plan could be implemented by 2025. The Tualatin Valley Water District expects its portion of the cost to be $408.3 million.

The district currently gets water from the Joint Water Commission, the Portland Water Bureau and its own aquifer storage and recovery well.

Water rates will go up when the district expands its capacity, but planning so far in advance could reduce sudden rate increases, Mark Knudson, the district’s chief engineer, said at the board meeting.

In 2007, the district voted to collaborate with other agencies to raise the Scoggins Dam and expand Hagg Lake to expand its long-term water supply. Although the district is still committed to that plan, the project will not be completed in time to meet the district’s needs as its service population grows.

The other option under consideration was to buy more water from Portland and build a pipeline from the Powell Butte Reservoir. However, the district would not have ownership rights over Portland’s water, as it would over the water drawn from the Willamette. The Portland option was projected to cost about $370.7 million.

The district staff’s most recent evaluation comparing the Willamette and Portland options rated the Willamette option as “more resilient” in eight of 12 categories, including seismic event risk and operations and maintenance costs.

Portland was considered more resilient only in the schedule category. The two options were considered equal in capital costs, political risk and regional economy changes.

The district serves more than 200,000 residents in Beaverton, Hillsboro, Tigard and unincorporated Washington County. Its service population is expected to grow by more than 100,000 by 2050.

The district’s current peak water demand is 49.5 million gallons a day, but it expects a peak demand of 72 million gallons a day by 2050.

“This decision tonight, if properly implemented, will enhance the control that this region has over its future,” said Commissioner Richard Burke. “I will be very happy to drink Willamette River water.”

Read originally posted article by Nicole Friedman at OregonLive.com

By Nicole Friedman | nfriedman@oregonian.com
on April 24, 2013 at 9:04 PM, updated April 25, 2013 at 2:40 PM