Hydrology and geochemistry of a Hawaiian geothermal system : HGP-A

dc.contributor.author Kroopnick, Peter M.
dc.contributor.author Buddemeier, Robert W.
dc.contributor.author Thomas, Donald M.
dc.contributor.author Lau, L. Stephen
dc.contributor.author Bills, David
dc.date.accessioned 2011-06-07T00:09:49Z
dc.date.accessioned 2011-09-29T20:11:22Z
dc.date.available 2011-06-07T00:09:49Z
dc.date.available 2011-09-29T20:11:22Z
dc.date.issued 1978
dc.description.abstract A water quality monitoring program of the Hawaii Geothermal Project well A (HGP-A) was conducted for downhole depth samples and continuous discharge samples in 1976 to 1977. The well water was slightly saline (about 5-10 percent ocean water) and nearly depleted of magnesium, but contained high concentrations of silica and sulfide. The chemical composition of the well water did not vary much with depth even though the sampling reached the well bottom [approximately 1768 m (5800 feet) below sea level]. The well fluid temperature was higher than that of any Hawaii ground water; a maximum of 358°C (676°F) was recorded at the bottom of the well. The water was low in tritium but unexpectedly high in carbon-14 when compared with the surrounding ground water [sampled as close as ~1609 km (1 mile) away]. Mass balance calculations involving carbon and its isotopes are consistent with a model proposing that 13 percent of recharge is from sea water. During continuous flow tests, the total well yield was 83,400 lb of steam per hour, equivalent to ~150 gpm with 70 percent steam and the rest water. For most constituents measured, there was a one to three day buildup period before approach to a steady state concentration. Water quality data, coupled with other measurements, indicate that the well is either poorly developed or located in a formation of low transmissivity. The moderately high rainfall and high surficial permeability allow substantial rain water infiltration. Actual subsurface water circulation is open to interpretation because of our uncertainty about geologic formations. Geophysical evidence suggests that deep dikes or intrusive bodies may be located on the ocean side of the well; such barriers would retard the encroachment of sea water into the well.
dc.description.sponsorship Funded by grants from the National Science Foundation (GI-38319) and the Energy Research Development Administration (EY-76-C-03-1093).
dc.format.extent 64 pages
dc.identifier.citation Kroopnick PM, Buddemeier RW, Thomas D, Lau LS, Bills D. 1978. Hydrology and geochemistry of a Hawaiian geothermal system: HGP-A. Honolulu (HI): Hawaii Institute of Geophysics, University of Hawaii at Manoa. Geothermal Resources Exploration in Hawaii, 4.
dc.identifier.uri http://hdl.handle.net/10125/20119
dc.language.iso en-US
dc.publisher Hawaii Institute of Geophysics, University of Hawaii at Manoa
dc.relation.ispartofseries Geothermal Resources Exploration in Hawaii: Number 4
dc.relation.ispartofseries HIG-78-6
dc.subject Hawaii Geothermal Project
dc.subject hydrology
dc.subject geochemistry
dc.subject hydrology
dc.subject chemical analysis
dc.subject groundwater
dc.subject.lcsh Groundwater--Hawaii--Puna Region
dc.subject.lcsh Geothermal resources--Hawaii--Puna Region
dc.title Hydrology and geochemistry of a Hawaiian geothermal system : HGP-A
dc.type Report
dc.type.dcmi Text
local.identifier.callnumber QC851 .H35 no.78-6 
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