105 Coastal Hydrogeology in an Age of Rising Seas (Posters)

As sea levels rise, understanding hydrogeology is crucial in coastal areas. Seawater intrusion can lead to loss of potable or agricultural water supplies, and water table rise due to increasing sea level can lead to increased flooding and affect infrastructure.

Monday, 20 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Modeling Coupled Stormwater-Wastewater-Groundwater Dynamics in Urban Coastal Settings

Paper number: 105-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Due to unprecedented climate change, coastal communities are increasingly vulnerable to sea level rise (SLR) and changing rainfall patterns. These impacts are especially pronounced in urban areas, where rising groundwater levels can overwhelm infrastructure by reducing the effectiveness of infiltration-based stormwater infrastructure and increasing inflow and infiltration (I&I) into wastewater systems. The resulting challenges, such as sewer overflows, rising utility costs, and public health risks, are exacerbated by limitations in current modeling approaches. Groundwater models often lack a detailed representation of urban infrastructure, while urban hydrology models typically fail to capture the complexity of coastal groundwater flow. To address these gaps, we developed an integrated modeling framework that couples the USGS MODFLOW6 and EPA SWMM models, enabling a dynamic, two-way exchange between groundwater and urban water systems. This coupling was achieved using the models' Python package and APIs (FloPy, PySWMM, and MODFLOWAPI), enabling real-time interaction between groundwater levels, infiltration rates, and sewer flows. We applied this framework to Bowers Beach, Delaware, a representative low-lying urban coastal community, to evaluate I&I and groundwater flooding potential under current and projected SLR scenarios. We evaluate the technical performance of the coupled model and discuss the added value of the coupled model over standalone approaches in capturing groundwater–infrastructure interactions. This work provides a critical foundation for utilities, planners, and policymakers to understand how climate-driven changes in groundwater may impact urban infrastructure. 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412287

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