AWWA ACE56225

The City of Wilsonville (City), population 14,000, is located along Interstate 5 at the north end of the Willamette Valley approximately 12 miles south of Portland. Although lying on the banks of the Willamette River, it has historically obtained water from eight wells located in an underlying deep bed basalt aquifer with steadily declining water levels. Projected system demands matched production leading to the declaration of a moratorium on new planning approvals (limiting the amount and rate of growth) in January 1998 pending the successful determination and construction of a new long-term water supply source. Staff was directed to conduct an evaluation of available options and to report back to the City Council with its findings. The three available options, along with the summarized reasons why each alternative was ultimately determined to be acceptable/unacceptable, include: additional wells, due to the City's location within a groundwater sensitive area, as established by the State of Oregon and local residential/agricultural objections, securing the necessary permits for additional wells was not possible; connection to Portland's "Bull Run" surface water system, due to the high construction costs, the need to traverse several neighboring communities with large diameter piping and the uncertainty of a long term water availability guarantee this option was similarly eliminated; and, a new water treatment facility on the Willamette River, given the treatability of the Willamette River, as confirmed by water quality studies extending back approximately ten years and recent pilot testing, the City Council determined that the Willamette River option best met it's long term water supply needs. Summarily, staff was directed to look to the construction of a state-of-the-art multi-barrier water treatment facility (Facility) producing water that would exceed EPA/State of Oregon drinking water standards. This alternative was additionally attractive due to the pre-existing (1973) water rights that the City held with it's partner, the Tualatin Valley Water District (TVWD). In 1999 an election was held in which the citizens of Wilsonville were asked to affirm the City Council's decision to choose the Willamette River as the City's long term water supply source and to approve $25,000,000 in revenue bonds to finance construction. With the successful passage, the City's revenue bond proceeds were combined with funding from TVWD for construction of the $43,000,000 facility. Construction commenced in July 2000.

Product Details

Edition:

Vol. - No.

Published:

06/16/2002

Number of Pages:

10

File Size:

1 file , 270 KB