IWRA Proceedings

The City of Portland Bureau of Water Works (PWB) has supplied domestic water to Portlandarea residents since 1885. It is the largest supplier in Oregon, and providing both retail and wholesale water to nearly 840,000 people. Portland’s primary source of supply, the Bull Run Reserve, is an unfiltered water source. The PWB faces a wide variety of challenges and uncertainties in the new millennium. These uncertainties arise from several principal sources: current federal regulatory requirements and potential future changes that affect water quality standards; treatment and the Endangered Species Act (ESA); conservation; decisions by current and potential wholesale customers about whether to obtain supply from Portland or elsewhere; decisions about where to obtain supply in the future and whether groundwater will be a basic component of the future supply or will be reserved only for emergencies; supply reliability; regionalization of the Portland’s supply system; demand forecasts; and the impact of climate variability. In an attempt to better understand these uncertainties, and develop a decision framework for an integrated strategy that will guide the timing and cost implications of the PWB’s capital improvement programs (CIP), the PWB has commissioned a number of technical studies over the past 5 years. The purpose of this paper is to discuss the decision process and the factors that have influenced and shaped the integration of the results of the studies, including the recently completed Climate Variability Study. The paper will also discuss the decision support systems developed by the PWB to facilitate the decision-making process.