MODFLOW-NWT model used to simulate groundwater flow in Wake County, North Carolina, 2000 through 2070

The U.S. Geological Survey (USGS) and Wake County Environmental Services developed a collaborative study to assess the hydrogeologic setting and groundwater flow conditions for Wake County, North Carolina. A groundwater-flow model was developed to conceptualize the fractured-rock aquifer system in Wake County and to assess historic and future groundwater resource availability. The MODFLOW-NWT (version 1.3.0) model simulates transient groundwater flow across two layers, incorporating recharge estimates from a previously developed Soil-Water-Balance (SWB) model (Antolino, 2021) for 2000-2019 in 82 seasonal stress periods. Model calibration using manual and automated parameter estimation with PEST (Doherty and Hunt, 2010) resulted in simulated values with an acceptable fit against observed groundwater levels and stream base flow observations. Six forecast scenarios were simulated for 2020-2070 with projected recharge datasets that incorporate projected land cover change and three general climate models under two future emissions scenarios. As Wake County is experiencing rapid population growth and increased demand on drinking water resources, the study results are intended to provide a scientific foundation for the ongoing management and future planning of Wake County’s groundwater resources.

This USGS data release contains all the input and output files for the transient simulations of the model described in the associated model documentation report (https://doi.org/10.3133/sir20255087). The readme.txt file contains information on model archive file structure and instructions for running the model simulations.

References:

-Antolino, D.J., 2021, Soil-Water-Balance (SWB) model data sets for the Greater Wake County area, North Carolina, 1981-2070: U.S. Geological Survey data release, accessed February 5, 2025, at https://doi.org/10.5066/P9MO793B.

-Doherty, J.E., and Hunt, R.J., 2010, Approaches to highly parameterized inversion—A guide to using PEST for groundwater-model calibration: U.S. Geological Survey Scientific Investigations Report 2010–5169, 59 p., accessed February 5, 2025, at https://doi.org/10.3133/sir20105169.