Publications

Ground-water recharge is estimated as the residual component of a monthly water budget calculated using soil characteristics and long-term average rainfall, streamflow, irrigation, and pan-evaporation data. The water-budget components of rainfall, direct runoff, evapotranspiration, and ground-water recharge are defined seasonally, through the use of monthly data, and spatially by land...

This report documents the results of an evaluation of the surface-water quantity, surface-water quality, and rainfall data-collection programs in Hawaii. Fourteen specific issues and related goals were identified for the surface-water quantity program and a geographic information systems (GIS) data base was developed summarizing information for all surface-water stream gages that have...

Detailed water budgets calculated for southern and southeastern Oahu are used with a geographic information system to develop simplified methods for estimating areal water budgets for predevelopment and mid-1980's land use. The methods were applied to estimate water budgets for the Waianae area of western Oahu, and for north-central, southern, and southeastern Oahu. A water budget was...

The island of Oahu, Hawaii, is the eroded remnant of two coalesced shield volcanoes, the Waianae Volcano and the Koolau Volcano. Shield-building lavas emanated mainly from the rift zones of the volcanoes. Subaerial eruptions of the Waianae Volcano occurred between 3.9 and 2.5 million years ago, and eruptions of the Koolau Volcano occurred between 2.6 and 1.8 million years ago. The...

The coastal plain in the Ewa area of southwestern Oahu, Hawaii, is part of a larger, nearly continuous sedimentary coastal plain along Oahu's southern coast. The coastal sediments are collectively known as caprock because they impede the free discharge of ground water from the underlying volcanic aquifers. The caprock is a layered sedimentary system consisting of interbedded marine and...

Oahu, the third largest of the Hawaiian islands, is formed by the eroded remnants of two elongated shield volcanoes with broad, low profiles. Weathering and erosion have modified the original domed surfaces of the volcanoes, leaving a landscape of deep valleys and steep interfluvial ridges in the interior highlands. The Koolau Range in eastern Oahu and the Waianae Range in western Oahu...

Ground-water recharge is estimated as the residual component of a monthly water budget calculated using long-term average rainfall, streamflow, irrigation, pan-evaporation data, and soil characteristics. The water-budget components are defined seasonally, through the use of monthly data, and spatially by topographic and geologic areas, through the use of a geographic information system...

Concern over potential effects from construction of the H-3 highway on Oahu, Hawaii, prompted a long-term study of streamflow and suspended-sediment transport at a network of five stream-gaging stations along the highway route. This report presents results for 1983-91, which included pre-construction and construction periods at all stream-gaging stations. Annual rainfall, streamflow, and

A dam constructed at the outlet of Bradley Lake near Homer, Alaska has blocked natural flows to the lower Bradley River. To protect salmon egg incubation habitat during the period November 2 to April 30, a fish-water bypass was incorporated into the design of the dam to ensure a minimum discharge of 40 cubic feet per second in the lower river. This minimum flow determination was based on...

The estimated total quantity of freshwater withdrawn on the island of Kauai, Hawaii, in 1990 was 370.84 million gallons per day of which 46.29 million gallons per day (12 percent) was from ground-water sources, and 324.55 million gallons per day (88 percent) was from surface-water sources. An additional estimated 40.94 million gallons per day of saline water was withdrawn for...

A geographic information system model was created to calculate a monthly water budget for the island of Kauai. Ground-water recharge is the residual component of a monthly water budget calculated using long-term average rainfall, streamflow, and pan-evaporation data, applied irrigation-water estimates, and soil characteristics. The water-budget components are defined seasonally, through...

Available ground-water data for East Molokai Volcano consist of well-construction information and records of ground-water pumpage, water levels, and chloride concentrations. Ground-water pumpage records are available for ten wells. Seventeen long-term (10 years or more) records of water-level and/or chloride concentration are available for eleven wells; however, only seven of these...