MODELING GROUNDWATER INUNDATION DUE TO FUTURE SEA LEVEL RISE IN HONOLULU, HAWAII

Vulnerability due to sea-level rise (SLR) is often imagined as seawater moving up and across the coastline, altogether overlooking the rise of the water table and eventual flooding of low-lying areas by groundwater inundation (GWI). Rotzoll and Fletcher (2012) developed a simple 1-dimensional model of water table elevation and tidal efficiency across a shore-normal transect in Honolulu, Hawaii to assess the effects of GWI. They assumed that SLR produces a nearly instantaneous rise of the water table, that will likely result in increased flooding, drainage problems, salinization of buried infrastructure, and storm damage during periods when rainfall and high tide are coeval. This study will expand on their research with an improved model that includes extensive groundwater and stratigraphic data gained from bore logs and archeological excavations from across the study area. The goal of the study is to simulate future GWI under most-likely scenarios of SLR using a transient 3-dimensional groundwater model (MODFLOW), and to test model sensitivity to SLR.