Delwyn S Oki
Delwyn Oki is a hydrologist with the Pacific Islands Water Science Center in Honolulu, Hawaiʻi.
Science and Products
Filter Total Items: 47
Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawai‘i, 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...
Authors
Kolja Rotzoll, Delwyn S. Oki, Adam G. Johnson, William R. Souza
Water-budget accounting for tropical regions model (WATRMod) documentation Water-budget accounting for tropical regions model (WATRMod) documentation
Regional groundwater recharge commonly is estimated using a threshold-type water-budget approach in which groundwater recharge is assumed to occur when water in the plant-root zone exceeds the soil’s moisture storage capacity. A water budget of the plant-soil system accounts for water inputs (rainfall, fog interception, irrigation, septic-system leachate, and other inputs), water outputs...
Authors
Delwyn S. Oki
January 18, 2022, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i January 18, 2022, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i
On January 18, 2022, groundwater levels were measured in selected wells in the Hālawa area, O‘ahu, Hawai‘i, constituting a synoptic groundwater-level survey (shortened herein to “synoptic survey”) of the area. Groundwater levels were measured mainly from 9:00 a.m. to 12:00 p.m. (times listed in Hawai‘i standard time) and provide a snapshot of groundwater levels during the survey period...
Authors
Rylen K. Nakama, Jackson N. Mitchell, Delwyn S. Oki
Estimating soil moisture, actual evapotranspiration, climatic water deficit, and groundwater recharge during periods of drought for current and future climate conditions in Hawaiʻi Estimating soil moisture, actual evapotranspiration, climatic water deficit, and groundwater recharge during periods of drought for current and future climate conditions in Hawaiʻi
Mid- and end-of-century climate projections for the Hawaiian Islands indicate that rainfall is projected to decrease across large areas. In areas affected by drought or where the future climate becomes drier, reduced groundwater recharge can affect freshwater availability. Reduced rainfall can also reduce soil moisture, which can increase the risk of wildfire. Cloud-water interception...
Authors
Alan Mair, Delwyn S. Oki
December 23, 2021, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i December 23, 2021, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i
On December 23, 2021, groundwater levels were measured in selected wells in the Hālawa area, O‘ahu, Hawai‘i, constituting a synoptic groundwater-level survey (shortened herein to “synoptic survey”) of the area. Groundwater levels were measured mainly from 9:00 a.m. to 12:00 p.m. (times listed in Hawai‘i standard time) and provide a snapshot of groundwater levels during the survey period...
Authors
Rylen K. Nakama, Jackson N. Mitchell, Delwyn S. Oki
Numerical simulation of the effects of groundwater withdrawal and injection of high-salinity water on salinity and groundwater discharge, Kaloko-Honokōhau National Historical Park, Hawaiʻi Numerical simulation of the effects of groundwater withdrawal and injection of high-salinity water on salinity and groundwater discharge, Kaloko-Honokōhau National Historical Park, Hawaiʻi
Kaloko-Honokōhau National Historical Park (KAHO) is located on the west coast of the island of Hawaiʻi and contains water resources exposed in fishponds, anchialine pools, and marine waters that are cultural resources and that provide habitat for threatened, endangered, and other culturally important native species. KAHO’s water resources are sustained by and dependent on groundwater...
Authors
Delwyn S. Oki
Science and Products
Filter Total Items: 47
Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawai‘i, 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...
Authors
Kolja Rotzoll, Delwyn S. Oki, Adam G. Johnson, William R. Souza
Water-budget accounting for tropical regions model (WATRMod) documentation Water-budget accounting for tropical regions model (WATRMod) documentation
Regional groundwater recharge commonly is estimated using a threshold-type water-budget approach in which groundwater recharge is assumed to occur when water in the plant-root zone exceeds the soil’s moisture storage capacity. A water budget of the plant-soil system accounts for water inputs (rainfall, fog interception, irrigation, septic-system leachate, and other inputs), water outputs...
Authors
Delwyn S. Oki
January 18, 2022, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i January 18, 2022, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i
On January 18, 2022, groundwater levels were measured in selected wells in the Hālawa area, O‘ahu, Hawai‘i, constituting a synoptic groundwater-level survey (shortened herein to “synoptic survey”) of the area. Groundwater levels were measured mainly from 9:00 a.m. to 12:00 p.m. (times listed in Hawai‘i standard time) and provide a snapshot of groundwater levels during the survey period...
Authors
Rylen K. Nakama, Jackson N. Mitchell, Delwyn S. Oki
Estimating soil moisture, actual evapotranspiration, climatic water deficit, and groundwater recharge during periods of drought for current and future climate conditions in Hawaiʻi Estimating soil moisture, actual evapotranspiration, climatic water deficit, and groundwater recharge during periods of drought for current and future climate conditions in Hawaiʻi
Mid- and end-of-century climate projections for the Hawaiian Islands indicate that rainfall is projected to decrease across large areas. In areas affected by drought or where the future climate becomes drier, reduced groundwater recharge can affect freshwater availability. Reduced rainfall can also reduce soil moisture, which can increase the risk of wildfire. Cloud-water interception...
Authors
Alan Mair, Delwyn S. Oki
December 23, 2021, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i December 23, 2021, Red Hill synoptic groundwater-level survey, Hālawa area, O‘ahu, Hawai‘i
On December 23, 2021, groundwater levels were measured in selected wells in the Hālawa area, O‘ahu, Hawai‘i, constituting a synoptic groundwater-level survey (shortened herein to “synoptic survey”) of the area. Groundwater levels were measured mainly from 9:00 a.m. to 12:00 p.m. (times listed in Hawai‘i standard time) and provide a snapshot of groundwater levels during the survey period...
Authors
Rylen K. Nakama, Jackson N. Mitchell, Delwyn S. Oki
Numerical simulation of the effects of groundwater withdrawal and injection of high-salinity water on salinity and groundwater discharge, Kaloko-Honokōhau National Historical Park, Hawaiʻi Numerical simulation of the effects of groundwater withdrawal and injection of high-salinity water on salinity and groundwater discharge, Kaloko-Honokōhau National Historical Park, Hawaiʻi
Kaloko-Honokōhau National Historical Park (KAHO) is located on the west coast of the island of Hawaiʻi and contains water resources exposed in fishponds, anchialine pools, and marine waters that are cultural resources and that provide habitat for threatened, endangered, and other culturally important native species. KAHO’s water resources are sustained by and dependent on groundwater...
Authors
Delwyn S. Oki