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
Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments
Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth
Authors
Kolja Rotzoll, Delwyn S. Oki, Aly I. El-Kadi
The Significance of Accounting Order for Evapotranspiration and Recharge in Monthly and Daily Threshold-Type Water Budgets
Most threshold-type water-budget models account for the loss of water by evapotranspiration before accounting for recharge. Recharge estimates can differ substantially, depending on whether recharge is counted before or after evapotranspiration in the water budget. This disparity is the source of uncertainty and is most pronounced for areas where soil-moisture storage capacity is small or for wate
Authors
Delwyn S. Oki
Effects of ground-water withdrawal on Kaunakakai Stream environmental restoration plan, Molokai, Hawaii
The U.S. Army Corps of Engineers, in cooperation with the County of Maui Department of Public Works and Environmental Management, has proposed to construct 2.75 acres of shallow ponds and mudflats near the mouth of Kaunakakai Stream, Moloka`i, Hawai`i to restore habitat for the endangered native Hawaiian Stilt. Kaunakakai Stream is ephemeral upstream from the habitat-restoration site. Where the po
Authors
Delwyn S. Oki
Effects of Surface-Water Diversion and Ground-Water Withdrawal on Streamflow and Habitat, Punaluu Stream, Oahu, Hawaii
The surface- and ground-water resources of the Punaluu area of northeast Oahu, Hawaii, have been and continue to be important for cultural, domestic, agricultural, recreational, and aesthetic purposes. Punaluu Stream flows perennially because rain falls frequently in the area and ground water discharges to the stream. Flow in Punaluu Stream is reduced by the direct diversion of water for off-strea
Authors
Delwyn S. Oki, Reuben H. Wolff, John M. Perreault
Numerical Simulation of the Hydrologic Effects of Redistributed and Additional Ground-Water Withdrawal, Island of Molokai, Hawaii
Because of increased demand for water associated with a growing population, projected increases in demand over the next few decades, and rising salinity of the water pumped from some existing wells, the County of Maui Department of Water Supply (DWS) is currently (2006) considering drilling additional wells to replace or supplement existing wells on the Island of Molokai, Hawaii. Redistributed and
Authors
Delwyn S. Oki
Numerical simulation of the effects of low-permeability valley-fill barriers and the redistribution of ground-water withdrawals in the Pearl Harbor area, Oahu, Hawaii
No abstract available.
Authors
Delwyn S. Oki
Effects of irrigation and rainfall reduction on ground-water recharge in the Lihue basin, Kauai, Hawaii
No abstract available.
Authors
Scot K. Izuka, Delwyn S. Oki, Chien-Hwa Chen
Trends in Streamflow Characteristics at Long-Term Gaging Stations, Hawaii
The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. Proper management of the surface-water resources of the State requires an understanding of the long- and short-term variability in streamflow characteristics that may occur. The U.S. Geological Survey maintains a network of stream-gaging stations in Hawaii, including a number of stations
Authors
Delwyn S. Oki
Trends in Streamflow Characteristics in Hawaii, 1913-2002
The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. In Hawaii, surface-water resources are developed for both offstream uses (for example, drinking water, agriculture, and industrial uses) and instream uses (for example, maintenance of habitat and ecosystems, recreational activities, aesthetic values, maintenance of water quality, conveyan
Authors
Delwyn S. Oki
Environmental Setting and the Effects of Natural and Human-Related Factors on Water Quality and Aquatic Biota, Oahu, Hawaii
The island of Oahu is the third largest island of the State of Hawaii, and is formed by the eroded remnants of the Waianae and Koolau shield volcanoes. The landscape of Oahu ranges from a broad coastal plain to steep interior mountains. Rainfall is greatest in the mountainous interior parts of the island, and lowest near the southwestern coastal areas.
The structure and form of the two volcano
Authors
Delwyn S. Oki, Anne M.D. Brasher
Surface Water in Hawaii
Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source
Authors
Delwyn S. Oki
Reassessment of ground-water recharge and simulated ground-water availability for the Hawi area of North Kohala, Hawaii
An estimate of ground-water availability in the Hawi area of north Kohala, Hawaii, is needed to determine whether ground-water resources are adequate to meet future demand within the area and other areas to the south. For the Hawi area, estimated average annual recharge from infiltration of rainfall, fog drip, and irrigation is 37.5 million gallons per day from a daily water budget. Low and high a
Authors
Delwyn S. Oki
Science and Products
Filter Total Items: 47
Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments
Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth
Authors
Kolja Rotzoll, Delwyn S. Oki, Aly I. El-Kadi
The Significance of Accounting Order for Evapotranspiration and Recharge in Monthly and Daily Threshold-Type Water Budgets
Most threshold-type water-budget models account for the loss of water by evapotranspiration before accounting for recharge. Recharge estimates can differ substantially, depending on whether recharge is counted before or after evapotranspiration in the water budget. This disparity is the source of uncertainty and is most pronounced for areas where soil-moisture storage capacity is small or for wate
Authors
Delwyn S. Oki
Effects of ground-water withdrawal on Kaunakakai Stream environmental restoration plan, Molokai, Hawaii
The U.S. Army Corps of Engineers, in cooperation with the County of Maui Department of Public Works and Environmental Management, has proposed to construct 2.75 acres of shallow ponds and mudflats near the mouth of Kaunakakai Stream, Moloka`i, Hawai`i to restore habitat for the endangered native Hawaiian Stilt. Kaunakakai Stream is ephemeral upstream from the habitat-restoration site. Where the po
Authors
Delwyn S. Oki
Effects of Surface-Water Diversion and Ground-Water Withdrawal on Streamflow and Habitat, Punaluu Stream, Oahu, Hawaii
The surface- and ground-water resources of the Punaluu area of northeast Oahu, Hawaii, have been and continue to be important for cultural, domestic, agricultural, recreational, and aesthetic purposes. Punaluu Stream flows perennially because rain falls frequently in the area and ground water discharges to the stream. Flow in Punaluu Stream is reduced by the direct diversion of water for off-strea
Authors
Delwyn S. Oki, Reuben H. Wolff, John M. Perreault
Numerical Simulation of the Hydrologic Effects of Redistributed and Additional Ground-Water Withdrawal, Island of Molokai, Hawaii
Because of increased demand for water associated with a growing population, projected increases in demand over the next few decades, and rising salinity of the water pumped from some existing wells, the County of Maui Department of Water Supply (DWS) is currently (2006) considering drilling additional wells to replace or supplement existing wells on the Island of Molokai, Hawaii. Redistributed and
Authors
Delwyn S. Oki
Numerical simulation of the effects of low-permeability valley-fill barriers and the redistribution of ground-water withdrawals in the Pearl Harbor area, Oahu, Hawaii
No abstract available.
Authors
Delwyn S. Oki
Effects of irrigation and rainfall reduction on ground-water recharge in the Lihue basin, Kauai, Hawaii
No abstract available.
Authors
Scot K. Izuka, Delwyn S. Oki, Chien-Hwa Chen
Trends in Streamflow Characteristics at Long-Term Gaging Stations, Hawaii
The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. Proper management of the surface-water resources of the State requires an understanding of the long- and short-term variability in streamflow characteristics that may occur. The U.S. Geological Survey maintains a network of stream-gaging stations in Hawaii, including a number of stations
Authors
Delwyn S. Oki
Trends in Streamflow Characteristics in Hawaii, 1913-2002
The surface-water resources of Hawaii have significant cultural, aesthetic, ecologic, and economic importance. In Hawaii, surface-water resources are developed for both offstream uses (for example, drinking water, agriculture, and industrial uses) and instream uses (for example, maintenance of habitat and ecosystems, recreational activities, aesthetic values, maintenance of water quality, conveyan
Authors
Delwyn S. Oki
Environmental Setting and the Effects of Natural and Human-Related Factors on Water Quality and Aquatic Biota, Oahu, Hawaii
The island of Oahu is the third largest island of the State of Hawaii, and is formed by the eroded remnants of the Waianae and Koolau shield volcanoes. The landscape of Oahu ranges from a broad coastal plain to steep interior mountains. Rainfall is greatest in the mountainous interior parts of the island, and lowest near the southwestern coastal areas.
The structure and form of the two volcano
Authors
Delwyn S. Oki, Anne M.D. Brasher
Surface Water in Hawaii
Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source
Authors
Delwyn S. Oki
Reassessment of ground-water recharge and simulated ground-water availability for the Hawi area of North Kohala, Hawaii
An estimate of ground-water availability in the Hawi area of north Kohala, Hawaii, is needed to determine whether ground-water resources are adequate to meet future demand within the area and other areas to the south. For the Hawi area, estimated average annual recharge from infiltration of rainfall, fog drip, and irrigation is 37.5 million gallons per day from a daily water budget. Low and high a
Authors
Delwyn S. Oki