Optimizing Aquifer Storage and Recovery Wellfield Operations to Minimize Energy Consumption

Abstract

In a world that is ever more focused on energy efficiency and climate change mitigation, minimizing energy consumption associated with pumping groundwater is a growing concern. In this study, a aquifer storage and recovery simulation-optimization model (ASRSOM) is developed to optimize aquifer storage and recovery (ASR) wellfield operations. ASRSOM combines an analytical hydraulic model and a numerical optimization model to optimize wellfield operations. The objective function used to minimize energy consumption is the temporal integral of the products of temporally varying total dynamic head values and pumping rates. Comparison of ASRSOM results with work by others for idealized aquifer operations supports the validity of ASRSOM. Four scenarios were simulated to evaluate the role that optimization of operations and aquifer recharge plays in reducing the energy required to pump groundwater out of the aquifer. The operations of a municipal ASR wellfield located in the Denver Basin, Colorado, were simulated for a 10-year period. Optimization decreased energy consumption by 2,179 MW h of power (−19.6% compared with historical scenario) and 1,541 t of atmospheric carbon. For the conditions considered, managed aquifer recharge reduced power consumption by 1%. The limited benefit of recharge is attributed to the small recharge volume in the case study, the short duration of the analysis, and the depth of water levels in the aquifer. Additional opportunities to address economic and environmental impacts associated with groundwater pumping include optimal position of wells and factors controlling total pumping head.