SEAWAT, MODFLOW-2000, and SHARP models used to simulate future water-supply scenarios, Cape May County, New Jersey

Three groundwater flow models, using MODFLOW-2000, SEAWAT, and 
SHARP model codes, were used to evaluate plans to supply potable and 
non-potable water to residents and businesses of Cape May County, New 
Jersey until at least 2050. The ideal plan would meet projected demands 
and minimize adverse effects on currently used sources of potable, non-
potable, and ecological water supplies. The U.S. Geological Survey used 
two previously developed groundwater flow models, as well as a newly 
developed groundwater flow model, to evaluate the shallow and deep aquifer 
systems in Cape May County.  The groundwater flow in the shallow and 
deep aquifer systems of Cape May County were simulated separately. 
Flow in the shallow aquifers was simulated with a newly developed small-cell-
size numerical model extending to the hydrologic boundaries. The saltwater 
transport modeling code, SEAWAT, was used to model the shallow system 
because of the accurate treatment of variable-density groundwater (saltwater 
front) and surface-water boundary (ecological-water supply) conditions. Flow 
in the deep aquifers was simulated using MODFLOW-2000 with a previously 
developed medium-cell-size numerical model encompassing Cape May County. 
This sub-regional groundwater-flow model (CMAC) was originally developed by 
Voronin (https://doi.org/10.3133/wri954280) to simulate advective flow in the 
Atlantic City 800-foot sand from the estimated 250-mg/L isochlor toward Stone 
Harbor. For this study, the CMAC model was revised to include the Rio Grande 
water-bearing zone and recalibrated with recent (2003) withdrawal data and 
water-level measurements. 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.  
To predict the effects of future actions on the water supplies, three baseline 
and six future scenarios were created and simulated with these three models. 
Depending on the scenario, proposed production wells would be installed in 
locations far from the saltwater fronts, in deep freshwater aquifers, in deeper 
saltwater aquifers, or proposed injection wells would be installed to inject 
reused water to create a freshwater barrier to saltwater intrusion.  Particle-
tracking was used with the CMAC model to estimate groundwater-flow paths 
and travel time from the location of the 250-mg/L isochlor to production wells 
or hypothetical production wells. 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/sir20095187).  

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, modpath, new-jersey, particle-tracking, rio-grande-water-bearing-zone, saltwater-intrusion, seawat, sharp, upper-kirkwood-aquifer, usgs-213a6ce1-90ce-4652-9fc8-d66024d85478, usgsgroundwatermodel
Organization: Department of the Interior