Assessment of Sea Level Rise Impacts on Aquifer Systems in Coastal Environments: A Case Study of Bowers Beach, Delaware

Abstract

As the sea level rises, high tides and storm surge increasingly push the saltwater-freshwater interface inland, thereby leading to saltwater intrusion into freshwater aquifers in coastal communities. Well-known consequences include the salinisation of drinking water and agricultural fields. Stormwater management and wastewater conveyance and treatment facilities may also be impacted by the rise of shallower, more saline groundwater. For example, when saline water infiltrates leaky sanitary sewer systems, this may reduce the integrity and effectiveness of wastewater conveyance and treatment. Similarly, when groundwater rises, infiltration-based stormwater best management practices may not work effectively because the vertical hydraulic gradient becomes weaker, which impedes infiltration. Through this research, we aim to holistically assess how sea level rise (SLR) impacts water infrastructure. Here, we use MODFLOW to simulate scenarios of SLR to investigate how much saline water intrusion and groundwater level rise is experienced by the freshwater aquifers in Bowers Beach, Delaware, a small coastal community with a history of flooding and saltwater intrusion concerns. This is the first step in our research that is geared towards understanding risks to stormwater, sanitary sewers and wastewater treatment facilities in the face of SLR, changes in precipitation patterns and groundwater level rise. Future modelling work of Bowers Beach will be channelled towards coupling this groundwater model with SWMM, a stormwater management model, to holistically simulate how these scenarios will impact stormwater systems and sanitary sewers in coastal environments.

Omowumi Erukubami

PhD Candidate

Carolyn B. Voter

Assistant Professor