Sea-Level Rise Effects on Delaware Bay Wetlands: Modeling Ecosystem Vulnerability and Informing Restoration

The coastal regions of New Jersey, including the wetlands on the Delaware Bay side, face significant challenges due to the impacts of sea-level rise (SLR). These effects include increasing water levels, heightened erosion, and frequent storm surges. Wetlands, critical components of coastal ecosystems, are particularly vulnerable to these changes. As sea levels rise, wetlands experience prolonged inundation, altered hydrodynamic flow patterns, vegetation loss due to drowning or reduced productivity, and increased salinity intrusion. These ecological disruptions compromise the health of wetland systems and pose a threat to the region's biodiversity, fisheries, and economy. Additionally, the loss of wetlands diminishes a critical natural buffer against coastal flooding, further increasing the vulnerability of New Jersey's coastline to the effects of climate change.

To address these challenges, advanced modeling techniques have been developed to simulate the impacts of SLR and provide decision-makers with actionable insights for restoration and future planning. Hydro-MEM, an integrated model, was developed by coupling hydrodynamic and marsh models to account for feedback mechanisms between hydrodynamics and wetland systems. This model captures key ecological and geomorphological processes, including changes in wetland productivity, migration patterns, vulnerability to SLR, and shifts in vegetation types.

For this study, Hydro-MEM was implemented for the New Jersey side of the Delaware Bay coastline, focusing on the impacts of various SLR scenarios on the region's wetland ecosystems. The model incorporates a range of hydrodynamic changes, including tidal variations, storm surge dynamics, and long-term sea-level trends. These scenarios allow for a comprehensive assessment of the future state of wetlands under different climate change projections.

The results highlight alarming trends under higher SLR scenarios. Wetlands are projected to lose significant productivity, with many areas transitioning from vegetated marshes to non-vegetated mudflats due to drowning. The spatial analysis of potential marsh migration suggests that the availability of suitable upland areas for migration will be critical to the survival of these ecosystems. Migration possibility maps derived from the model underscore the urgent need for proactive land management and restoration efforts to ensure that wetlands have adequate space to adapt to rising sea levels.

These findings emphasize the importance of integrated restoration strategies to mitigate the impacts of SLR. Measures such as land acquisition for marsh migration, sediment augmentation, and salinity management can enhance the resilience of wetland ecosystems. Furthermore, the Hydro-MEM model serves as a valuable tool for coastal planners and policymakers, offering a robust framework to evaluate the long-term effectiveness of restoration efforts and prioritize areas for intervention.

By advancing our understanding of the dynamic interactions between SLR and coastal wetlands, this research contributes to the broader goal of preserving the ecological and economic integrity of New Jersey's coastline. The insights gained from this study can inform similar efforts in other regions facing analogous challenges, ultimately supporting global efforts to adapt to the impacts of climate change.