SUTRA model used to evaluate long-term groundwater availability in the Waihe'e, 'Īao, and Waikapū aquifer systems, Maui, Hawaiʻi
Dates
Release Date
2022-01-01
Start Date
1926-01-01
End Date
2099-12-31
Publication Date
2023-09-15
Citation
Kolja, R., 2022, SUTRA model used to evaluate long-term groundwater availability in the Waihe'e, 'Īao, and Waikapū aquifer systems, Maui, Hawaiʻi: U.S. Geological Survey data release, https://doi.org/10.5066/P959B45F.
Summary
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawaiʻi, on the eastern flank of West Maui volcano, mainly in response to increased groundwater withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an increase in chloride concentrations of pumped water from production wells. These trends, combined with projected increases in demand for groundwater in central Maui, have led to concerns over groundwater availability and have highlighted a need to improve understanding of the hydrologic effects of proposed groundwater withdrawals in the Waiheʻe, ʻĪao, and Waikapū areas of central Maui. A three-dimensional, variable-density solute-transport model (SUTRA) was [...]
Summary
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawaiʻi, on the eastern flank of West Maui volcano, mainly in response to increased groundwater withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an increase in chloride concentrations of pumped water from production wells. These trends, combined with projected increases in demand for groundwater in central Maui, have led to concerns over groundwater availability and have highlighted a need to improve understanding of the hydrologic effects of proposed groundwater withdrawals in the Waiheʻe, ʻĪao, and Waikapū areas of central Maui. A three-dimensional, variable-density solute-transport model (SUTRA) was developed to evaluate the effects of seven selected withdrawal/recharge scenarios on water levels and salinity of groundwater in central Maui, Hawaiʻi. The model was constructed using water-level and salinity data available for the period from 1926 to 2012. Groundwater recharge for the model was estimated using a daily water budget for the period of interest. Inflow of groundwater at the model boundaries was estimated from an existing island-wide numerical groundwater-flow model (Izuka and others, 2021, available at https://doi.org/10.3133/sir20205126). The data release also includes the SUTRA source code and executable file used to run the simulations. The SUTRA code was modified to include a simplified representation of water-table storage (Gingerich, 2008, available at https://pubs.usgs.gov/sir/2008/5236/; Gingerich and Engott, 2012, available at https://pubs.usgs.gov/sir/2012/5010/). 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/sir20215113).
The three-dimensional, variable-density solute-transport groundwater model was created to evaluate the effects of seven selected withdrawal/recharge scenarios on long-term changes in water level and 50-percent ocean-water salinity depth, and simulated salinity of water withdrawn by existing and proposed production wells in central Maui, Hawaiʻi. An existing USGS numerical groundwater-flow and -transport model of central Maui (Gingerich, 2008) was used as a basis to develop an updated numerical model to address information needs related to: (1) quantifying the effects of withdrawal from existing or proposed wells on water levels and salinity of groundwater, (2) distributing withdrawals to increase the overall amount of fresh groundwater developed in the Waiheʻe, ʻĪao, and Waikapū aquifer systems, and (3) estimating the long-term effects of potential reductions in groundwater recharge on groundwater availability. The development of the model included in this data release is documented in U.S. Geological Survey Scientific Investigations Report 2021-5113 (https://doi.org/10.3133/sir20215113).
Preview Image
Image of the model domain and active area of the model.