SUTRA model used to evaluate the effects of groundwater withdrawal and injection, Kaloko-Honokohau National Historical Park, Hawaii

A three-dimensional, variable-density solute-transport model (SUTRA) was developed to evaluate the effects of three selected withdrawal/injection scenarios on salinity of groundwater (as simulated at damselfly anchialine-pool habitat) and discharge of freshwater to the nearshore environment of Kaloko-Honokohau National Historical Park (KAHO), Hawaii. A base model was constructed using water-level, salinity, and withdrawal data available during the period from 2009 to 2017. Groundwater recharge for the base model was from a published daily water budget representing rainfall for the period 1984-2008. The SUTRA code was modified to include simplified unsaturated zone properties in the subroutine UNSAT. Changes in salinity of groundwater and discharge of freshwater relative to the base model were quantified for two withdrawal and one injection scenario. Each of the withdrawal/injection scenarios consists of 15 model runs, representing 15 independently tested withdrawal/injection sites. Model parameter values for the three-dimensional model were initially estimated using a two-dimensional cross section model and the model code SUTRA-MS, which allows simulation of both salinity and heat transport. The two-dimensional cross-section model was used to evaluate model sensitivity to selected features or flow-system conceptualizations. The four sensitivity-analysis model simulations were: (1) no heat transport; (2) confining units for the deep, coastal confined-groundwater system with dip of 5 degrees instead of 1 degree in the base model; (3) thick upper confining unit; and (4) no confining units. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20215004).