IWRA Proceedings

The U.S. Army Corps of Engineers (Corps) is well known for its surface infrastructure, including locks and dams, levees and harbor channels. In recent years, managed aquifer recharge (MAR) has received increased consideration among traditional management measures typical of Corps projects. This presentation describes the first comprehensive review of the current and potential role of MAR in Corps water resources projects throughout the United States. 

The water needs of the U.S. are becoming more diverse and complicated, as evidenced by the increasing number of requests for reallocation of water stored in Corps reservoirs and tensions among competing water users. Opportunities for solving such challenges by building major new surface infrastructure are scarce and existing infrastructure is aging.

However, among these challenges lie opportunities. One such opportunity involves storage of water underground to effectively increase storage capacity of catchments and provide for potential later use of stored water for multiple water management purposes. MAR is increasingly considered by the Corps and its state and local partners as a water management measure that can increase flexibilities available to water managers and enhance effectiveness of existing water management infrastructure. MAR is a feature that has been considered among more conventional management measures typical of Corps studies, and has been the subject of some project authorities intended to support water conservation, drought preparedness, and ecosystem restoration.

A thorough review of Corps water resources planning and management activities in recent years shows the Corps or its partners are, or have at least considered, using MAR in at least 17 of the 50 states to support satisfaction of flood risk management and aquatic ecosystem restoration missions, and contribute to drought resilience, saltwater intrusion mitigation, and increased water availability. While cost and management burdens associated with MAR components are typically borne by non-federal partners, where both federal and non-federal interests are served and project authorities allow, some costs may be shared.

Despite such complexities, MAR’s increasing acceptance as a technology and a water management measure suggest that it will play an ever greater role in Corps projects. By providing additional seasonal and interannual storage, helping “flatten” flood stage hydrographs, contributing to environmental flows, and increasing availability of water for water users while moderating impacts to other water management purposes, MAR can help the Corps to deliver water management solutions that are sustainable and robust to a wider variety of climatic, environmental and demographic conditions.