New article finds groundwater pumping causes salinization of coastal streams

An article titled “Groundwater pumping causes salinization of coastal streams due to baseflow depletion: Analytical framework and application to Savannah River, GA” was published in the January 2022 issue of the Journal of Hydrology ( The paper provides a new analytical approach for assessing the impact of groundwater pumping on stream and river salinization. The study was led by Dr. Chelsea Peters (Roanoke College) and co-authored with Charles Kimsal (UD), Ryan Frederiks (UD), Anner Paldor (UD), Holly A. Michael (UD) and Rachel McQuiggan (DGS).

In coastal streams and rivers, fresh surface water flows from upland locations towards the ocean where it mixes with saltwater. However, because ocean water levels are not static and change depending on the tide, the upstream length of this mixing zone changes. In low-lying coastal areas like Delaware, groundwater contribution to streams and rivers can be as great as 80 percent of the total streamflow. When groundwater is pumped for drinking water or irrigation near coastal streams, it can reduce the amount of streamflow and cause upstream locations to salinize as salty ocean water encroaches further inland.

This study was funded by Project WiCCED ( as part of ongoing research on the potential salinization of Delaware’s water resources. For additional information, contact the Delaware Geological Survey at (302) 831-2833 or via email at

For questions and information, contact DGS at, 302-831-2833