- 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.
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
Available at: http://works.bepress.com/len_vacher/92/