Hydroeconomic Optimization and Reoperation of Folsom Reservoir for Flood-Managed Aquifer Recharge Implementation

Abstract

The increasing occurrence of prolonged droughts and extreme wet events in California poses significant challenges to the management of the region’s water resources. To address these challenges, the utilization of Flood-Managed Aquifer Recharge (Flood-MAR) has emerged as a potential solution. This study developed a multiobjective hydroeconomic model to assess the economic impact of implementing Flood-MAR and reoperation of Folsom reservoir within the American River Basin. The simulation module consists of a hydrological model and a linear programming groundwater recharge model. The economic impact evaluation considers three main components: the value of groundwater recharge, surface storage, and hydropower generation. The findings demonstrate that the adoption of Flood-MAR and reoperation of Folsom reservoir offer considerable economic benefits, with minimal adverse effects on the downstream system. Two different model solutions were analyzed: one that aimed to maximize recharge and storage benefits, and one that prioritized hydropower generation. The former exhibited an increase in reservoir storage compared with historical operation, along with increased water allocation for groundwater recharge during wet and normal years. The latter showed substantial gains in hydropower generation but occasional drops in reservoir storage below historical levels. Despite these differences, the solution emphasizing recharge and storage benefits was deemed to be more realistic, considering the risk of future droughts and uncertainties in climate and hydrological forecasts. Overall, this research provides a foundation for assessing the economic impact of Flood-MAR implementation in the Folsom reservoir system.