MODFLOW-2005 and SWI2 models for assessing groundwater and surface-water interactions in the Heeia Watershed, Oahu, Hawaii

Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the Heeia watershed, Oahu. A previously constructed steady-state numerical groundwater-flow model for the island of Oahu, Hawaii (https://doi.org/10.3133/sir20205126) using MODFLOW-2005 with the Seawater Intrusion (SWI2) package was used to examine the effects of withdrawals in the watershed. Four simulations representing a baseline and various withdrawal conditions were run using the previously published numerical model. The baseline simulation represents conditions in 2001-10 which were used to calibrate the Oahu model and to which all other scenarios are compared. The three scenarios include (1) a simulation of shutdown of Haiku Well, (2) a simulation of shutdown of Haiku Tunnel, and (3) a simulation of shutdown of Haiku Well and Haiku Tunnel. 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/sir20245020).