GSI staff developed a three-dimensional numerical groundwater flow model to aid multiple water providers in developing their wellhead protection strategies and the long-term capacity of their groundwater sources.


The Portland Water Bureau (Portland), the City of Fairview, and the Rockwood Water People’s Utility District (RWPUD) all obtain water from a multi-layered aquifer system that underlies parts of the City of Portland and its eastern suburbs in Multnomah County. Because of this they all needed to develop or update their municipal wellhead protections areas in conjunction with each other.

GSI’s Solution

Our staff originally developed a three-dimensional numerical groundwater flow model to evaluate the long-term sustainability of Portland’s wellfield and delineate its wellhead protection areas. For this most recent update, GSI applied this model to update Portland’s existing protection area and to develop new areas for Fairview and RWPUD. We worked with each client to identify the best projections of near-term and long-term operational schedules for sustainable groundwater pumping. This information was used to conduct simulations to help define the capture zones during various time periods. The model was used as a tool to identify the sources of significant risks for development of risk reduction policies within each water provider’s wellhead protection areas.