Once City Council directed the Water Bureau to begin planning for the construction and operation of a filtration plant, the determination of four key options was required to guide the planning and design phases: location of the treatment plant, the type of treatment method, size of the plant (how much water to treat each day), and the type of procurement (contract) method.
Three of these options were made within the context of the long-term water supply, demand and related issues in the region; community and Water Bureau values; and careful technical review and analysis. These options relate to: location, filtration type, and size. The fourth decision, procurement method, was made internally by City procurement, engineering and budget staff.
Site Location. The preferred location for the filtration facility is on Water Bureau owned property in rural, unincorporated Multnomah County, approximately four miles from the Bull Run Watershed main gate.
Type of filtration. Granular Media Filtration (GMF) has been chosen as the preferred method to filter Portland’s water. This process removes suspended solids by the passage of water through a porous medium. GMF is used by the majority of the comparable size water systems in the US.
Capacity. The facility will be able to filter up to 160 million gallons of drinking water per day (mgd). Current demands are up to 120 million gallons per day. The facility’s lifespan is approximately 100 years. Building to a capacity of 160 mgd should meet peak demands during its lifespan.
Procurement method. The procurement method chosen to design and construct the facility is Construction Management/General Contractor (CM/GC). This method allows the City to choose the most qualified and market-rate competitive bidder. Using the City’s Community Benefit Agreement, opportunities for racial and ethnic minority, and women owned businesses are maximized.