RAPID: Are short-lived storm surge events the key sources of long-term saltwater intrusion in coastal aquifers impacted by tropical cyclone activity?

The hypothesis of this RAPID project is that hurricane activity is the cause of a long-term saltwater intrusion into the coastal aquifer. There has been numerous hurricane activity on the US east coast that has disrupted the terrestrial hydrological system. One of this is storm surge following a hurricane. Basically, the storm surge results in water ponding on the land surface and the saltwater enters into the surface water storage as well as soil and groundwater by infiltration. In this project the PI and his team will use ground and surface water data for quantity, salinity and soil moisture information along with information of soluble salts in the soil to estimate saltwater intrusion in the fields. The methods will be based on field observations, analysis and numerical models. The presence of salinity is harmful to society - salinity in the soil results in lower agricultural productivity and salinity in the groundwater may contaminate household drinking water supplies. This work will be carried out along with extension personnel in North Carolina.

Storm surge resulting from hurricane activity results in infiltration of saline water that displaces the fresh groundwater and causes salinity of the soil and water table. There have been previous studies on impact of storm surge on groundwater, but this proposal goes further by quantifying the continuous high frequency variability of the solutes - specifically the decay over a course of over six months in the terrestrial surface and subsurface hydrologic system. The groundwater monitoring will be carried out using salinity measurements and water level loggers at a series of shallow intermediate and deep depths; surface water ? salinity loggers and water level depths and various solute measurements by using samples for the soil. The modeling system will use a combination of a one-dimensional analytical solution and the modeling package visual MODFLOW. The decay of the solutes will occur slowly after the recession of the storm surge and will continue for a period over months. The data generated in this study will be applicable for other locations in United States and globally.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.