Hydrogeological Evaluation of the Shay Pond Stickleback Habitat – Big Bear City, CA

California Department of Fish and Wildlife (2016)

Project Approach
TH&Co provided a hydrogeological assessment of the Shay Pond area in Big Bear City, California. The Shay Pond is a natural spring that provides a habitat for the Unarmored Threespine Stickleback fish (UTS). The California Department of Fish and Wildlife (CDFW) wanted TH&Co to identify the requirements necessary to restore, maintain, and possibly expand the habitat. To conduct the evaluation of the pond, TH&Co updated a previously developed groundwater flow model and expanded upon the previous work conducted to evaluate the pond. In addition, inspection of an existing well used to supplement water supply to the pond was evaluated.

Project Results
The Shay Pond Model was successfully calibrated to industry standards and used to analyze a new pumping well scenario that quantified the amount of water necessary to maintain the UTS habitat within Shay Pond.

Project Highlights and Accomplishments:
• Model area of approximately 8 square miles.
• Model constructed with one layer and discretized with 50-ft grid cells and a refined grid surrounding the pond with 10-ft grid cells
• Includes seasonal precipitation and evapotranspiration.
• Incorporates monthly stress periods.
• Includes pumping assumptions for private wells.
• Successfully calibrated for the period from 1992 through 2015.