Impact of Climate Change on Groundwater Resources on Virginia's Delmarva Peninsula

Abstract Submission: Groundwater resources on the southern section of the Delmarva peninsula, commonly called the Eastern Shore of Virginia (ESVA), are threatened by climate change. With no major rivers or reservoirs, the multi-layer aquifer system is classified as a sole-source aquifer and provides water supply to residential, agricultural, municipal, and industrial uses. To sustainably manage this multi-use groundwater system, the state of Virginia has a groundwater withdrawal permitting system. To evaluate the impact of groundwater withdrawals on both water volumes and on chloride concentrations, the state currently runs 50-year simulations using SEAWAT (MODFLOW extended to density-dependent flow) with a domain covering the entire ESVA. In addition, in this rural, low relief area, most residents use private septic systems. Under current conditions, some of these septic systems are already threatened by high water tables. In this research, we extend the state’s SEAWAT model to include expected climate changes, including sea level rise and changes in precipitation patterns. This region is expected to experience some of the fastest increases in sea level. Precipitation variability is expected to increase with recent future having more drought, followed by periods of greater flooding. Under these assumptions of climate change, we reassess the sustainability of subsurface resources for both overall supply, saltwater intrusion, and septic viability. This analysis serves as an example for other low-lying coastal areas.

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