Effect of an Offshore Sinkhole Perforation in a Coastal Confined Aquifer on Submarine Groundwater Discharge
submarine spring, sinkhole, submarine groundwater discharge, karst, freshwater, saltwater, transition zone, coastal aquifer, SUTRA, Florida
In order to explore submarine groundwater discharge in the vicinity of karst features that penetrate the confining layer of an offshore, partially confined aquifer, we constructed a three-dimensional groundwater model using the SUTRA (Saturated–Unsaturated TRAnsport) variable-density groundwater flow model. We ran a parameter sensitivity analysis, testing the effects of recharge rates, permeabilities of the aquifer and confining layer, and thickness of the confining layer. In all simulations, less than 20% of the freshwater recharge for the entire model exits through the sinkhole. Recirculated seawater usually accounts for 10–30% of the total outflow from the model. Often, the sinkhole lies seaward of the transition zone and acts as a recharge feature for recirculating seawater. The permeability ratio between aquifer and confining layer influences the configuration of the freshwater wedge the most; as confining layer permeability decreases, the wedge lengthens and the fraction of total discharge exiting through the sinkhole increases.
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Citation / Publisher Attribution
Effect of an Offshore Sinkhole Perforation in a Coastal Confined Aquifer on Submarine Groundwater Discharge, in C. Langevin, W. E. Sanford, M. Polemio & P. P. Povinec (Eds.), A New Focus on Groundwater-Seawater Interactions, International Association of Hydrological Sciences, p. 256-263
Scholar Commons Citation
Fratesi, Sarah E.; Vacher, H. L.; and Sanford, Ward E., "Effect of an Offshore Sinkhole Perforation in a Coastal Confined Aquifer on Submarine Groundwater Discharge" (2007). School of Geosciences Faculty and Staff Publications. 1814.