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    Geothermal resources of Hawaii
    (Hawaii Institute of Geophysics, University of Hawaii, 1983) Hawaii Institute of Geophysics, University of Hawaii at Manoa
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    A conceptual model of shallow groundwater flow within the lower east rift zone of Kilauea Volcano, Hawaii
    (University of Hawaii at Manoa, 1995-05) Novak, Elizabeth A.
    The discovery, development, and production of geothermal energy within the lower east rift zone (LERZ) of Kilauea volcano has been the impetus for development of models of shallow groundwater flow within the LERZ. During the last twenty years several models have been proposed. Each has drawn upon the preceding model, and has refined and improved upon it as new data became available. The purpose of this thesis research is to again refine the conceptual model of LERZ shallow groundwater flow using data from newly drilled wells and a data set acquired through continuous weIl monitoring, an approach which has not previously been used in the LERZ. The objectives of this research are twofold; first, the conceptual model will characterize the shallow unconfined aquifer present within the LERZ and lower south flank (LSF) in its natural state of dynamic equilibrium. Second, with commercial geothermal production beginning in this area, the data contained in this thesis will be used as a baseline to asses the impact, if any, of production and reinjection of geothermal fluids on the shallow LERZ groundwater aquifer. This research utilizes geochemical analyses from several recently drilled LERZ wells, as well as temperature, pressure, and conductivity data acquired through continuous monitoring of five wells on the lower north flank (LNF), LERZ, and the LSF of Kilauea. These data are used to characterize water level, temperature, and conductivity responses to recharge events; develop transmissivity and hydraulic conductivity values for the LNF, LERZ, and LSF; delineate groundwater flow paths within the LERZ; establish the percentage of geothermal fluid mixed with groundwater in various LERZ wells; estimate the temperature of the reservoir or reservoirs from which this geothermal fluid is derived; and identify the origin of their thermal fluids as either fresh or salt water.
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    Minearalogical assessment of reservoir fluid conditions, SOH geothermal drill holes
    (Hawaii Institute of Geophysics, University of Hawaii at Manoa, [n.d.]) Sykes, Martha L.
    "The purpose of this proposed research is to provide some preliminary answers to these questions, by the mineralogical, geochemical, and textural assessment of the State of Hawaii (SOH) drill holes 4, 2 and 1, as an aid to reservoir engineering assessment. A detailed knowledge of alteration mineral assemblages, their distribution and chemistry is essential for any future assessments of fluid-rock interactions in these drill holes."
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    Modeling hydrogeology and geothermal energy in the Kilauea East Rift Zone, Hawaii : a preproposal
    (1991-10)
    "To assist in providing the above-described information on the Kilauea ERZ hydrogeology, this proposal includes the following objectives: 1. To evaluate the overall hydrologic and hydraulic nature of the geothermal reservoir system, including : (a) Nature and distribution of the fluid flow system; is it dominated by continuum, fracture, or combination continuum-fracture flow? (b) Nature and extent of system boundaries including external and internal boundaries (c) Recharge sources and amounts (d) Reservoir parameters such as hydraulic conductivity, porosity, storativity, etc. 2. To evaluate the impact of re-injection of fluids on the geothermal reservoir and on the shallow fresh groundwater aquifer. 3. To evaluate the overall hydrologic nature and extent of the shallow fresh water aquifer and its interaction with the underlying geothermal reservoir."
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    A proposal for the chemical and mineralogical characterization of SOH cores
    ([s.n.], [n.d.]) Sinton, John; Hulsebosch, Thomas P.
    "We propose to provide chemical analyses and petrographic descriptions of selected samples from State of Hawaii Scientific Observation Holes 1, 2 and 4."
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    Proposal for acquiring zero-offset vertical seismic profile in SOH, Hawaii
    (Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, [n.d.]) Moore, Gregory; Fryer, Gerard
    "Total amount requested: $25,534"
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    Interim progress report - Geochemistry monitoring program (draft)
    (Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, 1994-03-18) Thomas, Donald M.
    The geochemical monitoring program has undertaken two related responsibilities: 1) Conduct a detailed analysis of the chemistry and dynamics of the shallow groundwater system on the Lower East Rift (LERZ); and 2) Evaluate the chemical composition of the geothermal fluids from the geothermal reservoir currently under development on the Kilauea East Rift Zone (KERZ). The objectives of the first effort are to characterize the baseline compositions of the shallow groundwater in the LERZ, to assess whether the geothermal development is having an adverse affect on the groundwater resources, develop a conceptual model for groundwater flow and mixing on the LERZ and to provide a data base with which to develop and validate a numerical model of this groundwater system. Analysis of the geothermal fluid compositions will provide us with the data necessary to determine whether shallow groundwater contamination is occurring and will enable us to assess some of the impacts that fluid production may be having on the long term viability of the geothermal reservoir. The shallow groundwater monitoring program has employed both continuous downhole monitoring instruments as well as repeated sampling of a variety of shallow groundwater sources located within and near the KERZ. Groundwater sources were chosen for monitoring included wells that were in close proximity to or down-gradient from, the geothermal system as well as sources that could provide baseline data that were unlikely to be affected by geothermal activities. Analysis of reservoir fluids have included both the liquid and steam phases generated by the geothermal production wells supplying steam to the PGV facility. The results that have been obtained to date for the groundwater monitoring program have shown that the groundwater system in lower Puna is very complex and is much different from those found elsewhere 4t Hawaii. Comparison of the variations in groundwater chemistry with the compositions of the geothermal fluids has not shown any detectable impact on groundwater quality from the geothermal development activities up to the present time. Analyses of the geothermal fluids has also shown that the fluids produced by the commercial production wells in the reservoir currently under development are quite different from those produced by the earlier HOP-A well, but have also found that substantial changes in production chemistry have occurred since production began in early 1993.
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    Two-domain estimation of hydraulic properties in macropore soils
    (Soil Science Society of America Journal, 1993-05/1993-06) Chen, Chuan; Thomas, Donald M.; Green, Richard E.; Wagenet, Robert Jeffrey
    Estimation of hydraulic: properties or soils having macropores is difficult, yet very important for describing soil-water flow dynamics. Conventional approaches of defining macroporosity based on pore size may not be generally successful quantitatively relating macroporosity to the dynamics of water flow. A definition or macroporosity based on water flux at different degrees or water saturation can be expected to be more useful. This study attempted to quantify the functional macroporosity of field soil from In situ measurements of water content, 6 (z, t), during drainage of an initially field-saturated soil. The soil was assumed to be a two-domain water flow system comprised of macropores, which dominate the early drainage process, and the matrix pore space, which is responsible for drainage occurring after macropores are emptied. The unit hydraulic gradient approach of calculating hydraulic productivity was extended and applied to the two-domain system. Field-measured data for a well-drained Wahiawa soil (clayey, kaolinitic, isohyperthermic Tropeptic Eutrustox) in Hawaii are used to test the approach. The partitioned hydraulic conductivities obtained for the two domains appeared qualitatively realistic, and when summed, resulted in a composite saturated conductivity which was close to that measured by the in situ instantaneous profile method. In addition, the macosporosites obtained from drainage calculations for three soil depths were very similar to those obtained from water retention measurements on undisturbed soil cores from the same field site. The proposed approach thus appears to be a promising method for evaluating hydraulic properties for a well-drained soil profile containing macrospores.
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    Silica recovery and control in Hawaiian geothermal fluids : final report
    (Hawaii Institute of Geophysics, University of Hawaii at Manoa, 1992-06) Thomas, Donald M.
    U.S. DOE Grant No. DE-FG07-88ID12741. A series of experiments was performed to investigate methods of controlling silica in waste geothermal brines produced at the HGP-A Generator Facility. Laboratory testing has shown that the rate of polymerization of silica in the geothermal fluids is highly pH dependent and increases rapidly as the brine pH is increased. At brine pH values in excess of 8. 5 the suspension of silica polymers flocculated and rapidly precipitated a gelatinous silica mass. Optimum flocculation and precipitation rates were achieved at pH values in the range of 10.5 to 11.5. The addition of transition metal salts to the geothermal fluids similarly increased the rate of polymerization as well as the degree of precipitation of the silica polymer from suspension. A series of experiments performed on the recovered silica solids demonstrated that methanol extraction of the water in the gels followed by critical point drying yielded surface areas in excess of 300 m2/g and that treatment of the dried solids with 2 N HCl removed most of the adsorbed impurities in the recovered product. A series of experiments tested the response of the waste brines to mixing with steam condensate and non-condensable gases. The results demonstrated that the addition of condensate and .NCG greatly increased the stability of the silica in the geothermal brines. They also indicated that the process could reduce the potential for plugging of reinjection wells receiving waste geothermal fluids from commercial geothermal facilities in Hawaii. Conceptual designs were proposed to apply the gas re-combination approach to the disposal of geothermal waste fluids having a range of chemical compositions. Finally, these designs were applied to the geothermal fluid compositions found at Cerro Prieto, Ahuachapan, and Salton Sea. Our analysis indicates that they could, under appropriate circumstances, be used at Cerro Prieto and Ahuachapan but not at the Salton Sea geothermal field.