USGS Grant Number: G19AP00005
Year Established: 2018 Start Date: 2019-02-01 End Date: 2022-01-31
Total Federal Funds: $195,215 Total Non-Federal Funds: $195,215
Principal Investigators: Holly A. Michael
Abstract: Coastal flooding caused by storm surges can cause devastating impacts to life and surface infrastructure. Although less immediate, the effects of coastal flooding on the quality of groundwater resources may have major impacts on coastal populations for decades after a surge event. Not only are terrestrial waters contaminated with seawater, but associated effects such as mobilization of soil-bound contaminants can compound adverse effects on water resources, agriculture, and sensitive ecosystems. These impacts are likely to increase as climate change and sea-level rise (SLR) cause coastal storms to increase in frequency and intensity, groundwater salinity to increase, water tables to rise, and coastlines to encroach landward. Due to the hidden and intermittent nature of these effects, the impacts on groundwater quality and ecosystem health have not been well studied. To enhance our ability to predict the impacts of extreme coastal flooding events on groundwater quality and coastal ecosystems and assess vulnerability, we must improve our understanding of the processes of groundwater salinization and flushing after surge events and identify the most critical indicators of salinization potential. We propose to investigate the vulnerability of fresh groundwater resources and ecosystems in coastal zones to salinization due to storm-surge inundation and SLR. We will focus on three barrier-island field sites in New York, New Jersey, and Maryland/Virginia, and more broadly on the US Mid-Atlantic and Gulf Coastal Plain coastlines. The Mid-Atlantic region is among the most vulnerable in the US due to its low topography, frequency of intense storms, and high relative rate of SLR. Our objectives are to: 1) analyze data collected by recent and ongoing USGS studies as well as limited field data collected by this study from 1 or 2 storm events; 2) develop calibrated, transient, coupled groundwater-surface water models of three sites based on existing USGS steady-state groundwater models and water-level and salinity data; 3) vary model hydrologic conditions to assess impacts on groundwater salinization and flushing at those sites under current and future conditions, and develop vulnerability maps; 4) create generic models and vary hydrologic, geologic, and geomorphic properties to extend the analysis to include coastal zones typical of Coastal Plain coastlines, 5) develop vulnerability typologies, and 6) engage stakeholders.