On May 22, the Lake Oswego and Tigard City Councils met jointly to receive an update on the Lake Oswego Tigard Water Partnership. The report covered the Partnership’s progress on design, permitting, public outreach, project schedule and budget.
The project team reported that engineering design efforts are on schedule to meet the Partnership’s June 2016 completion goal. Program expenditures to date and estimated project costs remain within the budgeted range. Water rate increases already approved by Lake Oswego and Tigard Councils will be sufficient to cover the projected costs.
Several important milestones will be achieved over the next 12 to 18 months.
- Resolution of an appellate court proceeding concerning the Water Resources Department's approval of Lake Oswego’s municipal water rights extensions.
- Securing all necessary environmental approvals from federal and state agencies
- Completion of engineering and design activities.
Policy makers, working with our engineering design team, have several important changes in the scope of the project to assure additional public safety, the highest quality water, and the lowest long-term cost. Detailed project cost estimates prepared at the 30% design stage show anticipated costs are 4% to 9% higher than the $230 million preliminary estimate in Fall 2010.
The most significant modification to the original plan has been the decision to build out the water treatment plant to its full 38 mgd (million gallons per day) capacity now rather than at some point in the future. Making this additional investment now eliminates future land use and cost uncertainty and provides a much needed community benefit to West Linn in the form of a more reliable and increased supply of water for emergency use.
Site-specific geologic conditions also led the Partnership to require that the structural design of new facilities be robust enough to keep the new plant operable and occupiable even after a magnitude 9 subduction zone earthquake.
The existing Bonita Pump Station will be replaced with a larger, dual pumping facility at a new location. This key facility connects Lake Oswego’s water supply to Tigard customers. Dual pumping capability eliminates the need to construct a second pump station to meet Tigard’s future water needs while improving the quality of water provided to Tigard residents..
Several pipeline alignments have been changed to replace aging pipes and reduce impacts on neighbors and the environment. Pipeline segments constructed underneath the Willamette River and under Oswego Lake will use a trenchless technology called Horizontal Directional Drill or HDD.
Costs for the water supply partnership are funded through bond sales that are repaid with monthly water rates. Tigard recently sold $102 million dollars of municipal bonds in April 2012, and received very favorable rate of 4.03% -- well below the projected level. Lower interest rates reduce financing costs.June 07, 2012