City of Auburn
Project: Hydrogeologic Characterization & Groundwater
Location: Auburn, Washington
The City of Auburn has been developing new groundwater supplies and pursuing
additional water rights for many years. PGG has supported these endeavors
by conducting a comprehensive hydrogeologic characterization and by monitoring
water levels, stream flows, and water quality on an ongoing basis. To
procure new water rights and meet the demands of the area’s expanding
population, the utility must demonstrate that it can manage its water
supplies without impacting the stream closures that have been established
for the White and Green Rivers. This requires quantifying stream-aquifer
relationships within the study area using a comprehensive groundwater
Developing a meaningful groundwater flow model requires large amounts
of high-quality data and extensive calibration. The hydrogeology of the
area is complex, particularly in the uplands, which are glacial in origin.
The model needed to be robust enough to handle this complexity and to
simulate a range of pumping options.
Prior to developing the digital flow model, we quantified water-budget
components, including groundwater pumpage, spring flow, bluff seepage,
and recharge. Local purveyors were contacted to provide data about their
water usage. We estimated aquifer recharge using a Deep Percolation Model
and a series of equations developed by the U.S. Geological Survey (USGS).
Because the data sets for this project were extremely large, we relied
on a Geographic Information Systems (GIS) approach for most of the water-budget
analyses. The digital flow model was based on a conceptual model that
we developed from our hydrogeologic characterization work. The model domain
encompassed 250 square miles and featured eight layers, a variable grid
size, and 158,309 active cells. We calibrated and tested the model for
both transient and steady-state conditions.
The City now has model a valuable tool for managing its water supplies
and supporting its water rights applications.
Protection / City of Auburn: Wellhead Protection Studies
Rights Support / City of Auburn: Water Rights Investigations