GROUNDWATER DEVELOPMENT

PROPERTY TRANSFER
REMEDIAL INVESTIGATION & CLEANUP
EXPERT WITNESS
WELLHEAD PROTECTION
SOLID WASTE COMPLIANCE
WATER RIGHTS SUPPORT
DATA MANAGEMENT
GROUNDWATER MODELING
• City of Auburn
• Clark Public Utilities
WATERSHED ASSESSMENT
AQUIFER STORAGE & RECOVERY
WASTEWATER & STORMWATER RECHARGE
 

Client: City of Auburn
Project: Hydrogeologic Characterization & Groundwater Flow Modeling
Location: Auburn, Washington

Background
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 flow model.

Challenges
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.

Approach
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.

Outcome
The City now has model a valuable tool for managing its water supplies and supporting its water rights applications.

Related Projects

Wellhead Protection / City of Auburn: Wellhead Protection Studies

Water Rights Support / City of Auburn: Water Rights Investigations

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