SEAWAT, MODFLOW-2000, and SHARP models used to simulate potential water-allocation changes, Cape May County, New Jersey

Three existing groundwater flow models, using MODFLOW-2000, SEAWAT, and 
SHARP model codes, were used by the U.S. Geological Survey (USGS) to 
determine the effects of increased withdrawals, and shifts of withdrawals between 
2 aquifers, on the limited water resources in the Cape May County, New Jersey. 
Saltwater intrusion and declining water levels have been a water-supply problem in 
Cape May County for decades. Several communities in the county have only one 
aquifer from which freshwater withdrawals can be made, and that sole source is 
threatened by saltwater intrusion and (or) substantial declines in water levels 
caused by groundwater withdrawals. Growth of the year-around and summer 
tourism populations have caused water demand for some purveyors to approach 
full-allocation withdrawal rates leading these purveyors to request increases in 
allocations. The three groundwater flow models were used to evaluate the shallow
and deep aquifer systems of Cape May County. The groundwater flow in the shallow
and deep aquifer systems were simulated separately. The lateral hydrologic 
boundaries of the shallow aquifer system generally coincide with the political 
boundary of Cape May County, whereas the boundaries for the deep aquifer system
extend well beyond the county boundaries. Flow in the shallow aquifers was simulated
with the saltwater-transport modeling code, SEAWAT. Flow in the deep aquifers was
simulated using MODFLOW-2000 with a medium-cell-size numerical model (CMAC) 
encompassing Cape May County (https://doi.org/10.3133/wri954280) that was revised 
to include the Rio Grande water-bearing zone and recalibrated with recent (2003) 
withdrawal data and water-level measurements for a previous study of the Cape May 
County water resources (https://doi.org/10.3133/sir20095187). Boundary flows to the 
CMAC model were provided from the New Jersey Coastal Plain regional model (NJCP 
SHARP) (https://doi.org/10.3133/wri984216).  This coarse-cell-size Coastal Plain-wide 
model uses the SHARP model code and simulates saltwater movement by treating 
the transition from freshwater to saltwater as a sharp interface, and therefore, only 
predicts large-scale movements of the 10,000-mg/L isochlor. Future groundwater 
withdrawal scenarios for the shallow and deep system were compared to baseline 
scenarios in an effort to balance the need for additional water with protection of the 
limited water resources in the county. This USGS data release contains all the input 
and output files for the simulations described in the associated model documentation 
report (https://doi.org/10.3133/sir20205052)  

Tags: atlantic-city-800-foot-sand, cape-may-county, cohansey-aquifer, environment, geoscientificinformation, groundwater, groundwater-management, groundwater-model, inlandwaters, kirkwood-cohansey-aquifer, lower-kirkwood-aquifer, modflow-2000, new-jersey, rio-grande-water-bearing-zone, saltwater-intrusion, seawat, sharp, upper-kirkwood-aquifer, usgs-ee56cd2e-bde0-49aa-b0ad-49da2a6696de, usgsgroundwatermodel
Organization: Department of the Interior