In a rapidly developing region near Reno, Nevada, aquifer recharge efforts were originally supported by comprehensive technical evaluations conducted in the 1980s and 1990s. The aquifer recharge efforts influenced well performance and changes in the recharge practices had potential for affecting several hundred water right users. The original technical data was sufficient to convince stakeholders to invest in construction and operation of the aquifer recharge program. Part of the initial investigation into the feasibility of aquifer recharge was the development of a groundwater flow model. Steady-state and transient groundwater flow models for the basin were updated in 2017, and the transient model was calibrated using data collected prior to ceasing aquifer recharge operations. Other components included analysis of surface water availability, the economic feasibility of the project, and the chemistry of the basin groundwater and proposed infiltration water.

Scope of Services

Terraphase’s approach focused on evaluating how basin conditions have changed since the original program design and utilizing that new understanding to revise and recalibrate the 2017 model to current conditions. Our team assessed the adequacy of historical data and supplemented it with new information, including bedrock surface development from over 100 wells, pumping depths from 530 domestic well logs, and hydraulic conductivity derived from 140 well yield records. This work supported the refinement and recalibration of the MODFLOW groundwater model, allowing for predictive scenario analysis to inform future aquifer recharge decisions. The Terraphase team also developed a conceptual site model and prepared a final technical report and public presentation.

Notable Accomplishments

• Integrated new and historical data to refine basin understanding
• Developed and calibrated a MODFLOW model incorporating over 100 well records
• Evaluated over 500 domestic well logs to characterize pumping depths and
  derived hydraulic conductivity values from 140 well yield data sets
• Delivered a comprehensive conceptual site model and predictive groundwater analysis
• Informed future aquifer recharge strategies with calibrated model scenarios
• Provided final technical documentation and supported public engagement through presentations
• Our analysis gained wide public support and was selected for a paper presentation at the February 2023 Nevada Water Resources Association conference.