J Street, Sacramento, CA 95819-6043, Water quality in coastal aquifers can be threatened not only by upconing and saltwater intrusion, but also by overwash during severe storms.
Storm surge causes flooding that recharges water-table aquifers with saline water.
In extreme cases, overwash has penetrated the interior of Hatteras Island by more than one km. By January 1997, chloride levels still had not reached pre-flooding concentrations. Simulated and field chloride levels along Transect 1 rise during the summer months in response to higher pumping rates and limited aquifer recharge. Simulated chloride concentrations return to pre-storm levels by January 1997. Modeling results are different for Transect 2 because of less extreme overwash and a larger island width.