District Board Weighs Long-Term Water Supply Options
By Marilyn McWilliams, TVWD Board Member

At their April 24 meeting, the Tualatin Valley Water District (TVWD) Board of Commissioners unanimously adopted the Mid-Willamette River at Wilsonville as the District’s preferred long-term water supply option. The four options studied were: the Northern Groundwater wells near Scappoose; the Tualatin Basin Water Supply Option or TBWSP (Hagg Lake) presently in use; an additional pipeline to the Portland Water Bureau; or the Mid-Willamette source in Wilsonville. At this time the District uses Portland Water Bureau water and Joint Water Commission water from Hagg Lake.

The board has been studying the options for over a year, and took into account financial and non-financial criteria, costs for construction, cost sharing with partners, risks for delays and cost escalation, and long term effects upon water rates.

The Northern Groundwater option was eliminated because of high construction and operational costs, customer concerns, and high risk for problems. The TBWSP was eliminated because of delays in working with our federal partners, sustainability concerns, and limits on capacity to meet demand. Portland Water Bureau presents governance risks, since TVWD does not own the source, and has no say in decisions such as the proposed fluoridation. The Mid-Willamette source is plentiful, provides strong partners, proven water quality, and ownership of the source. It also provides a third water source, important in a drought or a natural disaster.

The Wilsonville Water Treatment Plant

Looking at costs for planning and construction only, Portland has the least cost—$370 million, compared to the Mid-Willamette at $408 million. However, looking at long-term costs, including risks, the Mid-Willamette would result in the lowest customer rates. Compare this to the decision to buy a new car. You can look at only the sticker cost of the car, and choose the cheapest car. But if you want to keep the car for a long time, you would compare the costs for gas, maintenance, insurance and reliability. This supply option is meant to last for a hundred years, so long-term costs are critical.

“The Board’s top priority is to secure a reliable and high quality additional supply of water. The Willamette River is a proven, abundant and affordable water source,” explained TVWD Board President, Dick Schmidt.

Based on projected population growth, and to help sustain Washington County’s expanding job base, TVWD will require an additional source of water supply around the year 2025. “It will take over a decade to plan, design and construct the new supply, so the District must start now to make sure the required improvements are in place when needed,” says TVWD Chief Executive Officer Greg DiLoreto.

Washington County Chair Andy Duyck attended the District board meeting, and pointed out the role of Washington County as “the economic engine of the state.” He testified that, “The fuel for this engine, and the ingredient that makes this possible is pure, clean water.”

Pam Treece, Executive Director of Westside Economic Alliance, also testified. “A quality and reliable water supply is required to support our existing communities and businesses. It is also fundamental to the expansion of existing companies and the recruitment of new companies,” said Treece.

The City of Wilsonville has continuously provided residents and businesses with water from the Willamette River for 11 years. Sherwood also recently began drawing on the Willamette as a water source. DiLoreto notes, “This source has reliably met the needs of these communities by providing quality water with no water quality violations during that time.”

TVWD’s Board directed staff to develop a plan for implementing the Board’s decision to pursue the Mid-Willamette River at Wilsonville as the preferred supply option. The Board will consider an implementation plan at their May 15 meeting. The District will continue to inform and involve customers in developing the Willamette River water source over the next decade.

The District’s portfolio of drinking water supplies already includes the Tualatin/Trask watersheds, water purchased from the Portland Water Bureau, and an aquifer storage and recovery (ASR) well. All of these supplies will continue to provide water for the foreseeable future.

If Portland voters decide to fluoridate its water supply, the water that TVWD gets from them will be fluoridated. Residents of the former Wolf Creek part of the District (including Cedar Mill, see November 2012 article) voted to have fluoridated water in 1964, and TVWD adds it to that part of the system. The other stream of water from the Portland supply line goes to the Metzger section of the District, which has never voted on fluoride. If Portland approves fluoridation, TVWD will no longer have to fluoridate the Wolf Creek part of the supply, but the customers in Metzger will have no choice but to receive fluoridated water.

For more information about TVWD’s long-term water supply options, visit our website, TVWD.org.

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