Estimating Monetized Benefits of Groundwater Recharge from Stormwater Retention Practices
New EPA Study Supports The Long-term Benefits of Green Infrastructure
EPA encourages green infrastructure for urban areas because of their benefits to water quality and stream channel protection. Groundwater recharge is a co-benefit of reducing excess stormwater runoff volume associated with impervious areas. This study was commissioned to estimate the groundwater recharge benefits from application of small storm retention practices on new development and redevelopment nationwide. Broad assumptions, national datasets, and simplified recharge calculation and monetization approaches were used to provide general insight into the monetary benefits of small storm retention practices. The assumptions and limitations are listed in the study to facilitate future researchers’ efforts. The study focuses on areas in the United States where groundwater is a significant contributor to urban and agricultural uses and where water shortages may occur. The approach was vetted by a panel of experts from government, academia and industry, with recommendations for improved methodologies for future studies. The results suggest that over time the use of green infrastructure can save hundreds of millions of dollars in groundwater resources when only applying the practices to new development and redevelopment. If retrofitting or increased retention were to occur, the groundwater benefits would be even more significant.