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• 171. [Image] Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report.

  	Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements ...
  	Citation × Citation Citation Abstract Copy Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report. Author: Skokan, C.K. Year: 1978 Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements were performed at atmospheric pressure and room temperature. Various methods of measuring thermal conductivity were investigated and finally a flash method was chosen. The equipment was constructed and tested. The results were favorable. Numerous capillary pressure curves were obtained by use of the mercury injection technique. These curves indicate pore structure: pore size, pore distribution, pore volume, and pore geometry. Measurements of this type help to explain variations in rock properties such as seismic velocities and resistivities Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report. Author: Skokan, C.K. Year: 1978 Laboratory measurements of thermal conductivity and capillary pressure have been undertaken for samples of Cenozoic Volcanic rocks collected from the Columbia Plateau Volcanic basin. These measurements were performed at atmospheric pressure and room temperature. Various methods of measuring thermal conductivity were investigated and finally a flash method was chosen. The equipment was constructed and tested. The results were favorable. Numerous capillary pressure curves were obtained by use of the mercury injection technique. These curves indicate pore structure: pore size, pore distribution, pore volume, and pore geometry. Measurements of this type help to explain variations in rock properties such as seismic velocities and resistivities Close

• 172. [Image] Geopressured Geothermal Fairway Evaluation and Test-Well Site Location Frio Formation, Texas Gulf Coast

  	Tertiary strata of the Texas Gulf Coast comprise a number of terrigenous depositional wedges, some of which thicken abruptly at their downdip ends as a result of contemporaneous movement of growth faults ...
  	Citation × Citation Citation Abstract Copy Title: Geopressured Geothermal Fairway Evaluation and Test-Well Site Location Frio Formation, Texas Gulf Coast Author: Bebout, D.G. Year: 1978 Tertiary strata of the Texas Gulf Coast comprise a number of terrigenous depositional wedges, some of which thicken abruptly at their downdip ends as a result of contemporaneous movement of growth faults and underlying salt. The Frio Formation, one of these wedges, has been studied regionally by means of a grid of correlation cross sections aided by micropaleontological control. By means of these sections, the Frio was subdivided into six map units; maps of sandstone distribution within these units delineate principal elongate sandstone trends parallel to the Gulf Coast composed of deltaic, barrier-bar, and strandplain sandstones. These broad regional studies, followed by detailed local investigations, were pursued in order to delineate prospective areas for production of geopressured geothermal energy. A prospective area must meet the following minimum requirements: reservoir volume of 3 cubic miles, minimum permeability of 20 millidarcys (md), and fluid temperatures of 300° F. Several geothermal fairways were identified as a result of this Frio study Title: Geopressured Geothermal Fairway Evaluation and Test-Well Site Location Frio Formation, Texas Gulf Coast Author: Bebout, D.G. Year: 1978 Tertiary strata of the Texas Gulf Coast comprise a number of terrigenous depositional wedges, some of which thicken abruptly at their downdip ends as a result of contemporaneous movement of growth faults and underlying salt. The Frio Formation, one of these wedges, has been studied regionally by means of a grid of correlation cross sections aided by micropaleontological control. By means of these sections, the Frio was subdivided into six map units; maps of sandstone distribution within these units delineate principal elongate sandstone trends parallel to the Gulf Coast composed of deltaic, barrier-bar, and strandplain sandstones. These broad regional studies, followed by detailed local investigations, were pursued in order to delineate prospective areas for production of geopressured geothermal energy. A prospective area must meet the following minimum requirements: reservoir volume of 3 cubic miles, minimum permeability of 20 millidarcys (md), and fluid temperatures of 300° F. Several geothermal fairways were identified as a result of this Frio study Close

• 173. [Image] Geothermal Exploration of the Puga and Chumathang Geothermal Fields, Ladakh, India

  	Puga and Chumathang Geothermal fields are situated near the collided junction of the Indian and Asian Crystal plates and thermal activity in these fields is attributed to the widespread igneous activity ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Exploration of the Puga and Chumathang Geothermal Fields, Ladakh, India Author: Shanker, R. Puga and Chumathang Geothermal fields are situated near the collided junction of the Indian and Asian Crystal plates and thermal activity in these fields is attributed to the widespread igneous activity of Upper Cretaceous to late Tertiary age. A deep suture zone, recognised in between these two fields and the associated faults provide channels for the upward migration of the thermal fluids. High concentrations of Cl, F, Si02, B, Na, Li, Rb, Cs in thermal fluids signify contribution of magmatic bodies towards heat, and fluid supply. These fields are characterized by high heat flow conditions (13 HFU), abnormal shallow geothermal gradients (0.7 - 2.5 c/m) , high base temperature (220 - 270 C) as obtained by alkalia and Ne-K-Ca geothermometry and low resistivity values (2-20 ohm.m.). Low resistivity zones occupy on an area of three and one sq.km. and extend down to maximum depths of 300 m. and 130 m. at Puga and Chumathang respectively. Shallow drilling (28-130 m.) has established the existence of wet steam reservoirs under moderate pressure (2-4.5 kg/cm^2). Hot fluid (95-135 C) discharges from eight flowing wells ranged from 7.5 to 30 t/h. These thermal fluids are stored in the partly consolidated fluvioglacial deposits of Quarternary to Recent age. The occurrence of a limestone layer in the country rock at Puga brightens the prospects of getting good reservoir at depth. In both these fields two aquifers have been recognised, each having sizeable potential for retaining ground water. The ground water recharge is mainly through snow melt from glaciers in the case of Puga field and principally from Indus river in the case of Chumathangfield Title: Geothermal Exploration of the Puga and Chumathang Geothermal Fields, Ladakh, India Author: Shanker, R. Puga and Chumathang Geothermal fields are situated near the collided junction of the Indian and Asian Crystal plates and thermal activity in these fields is attributed to the widespread igneous activity of Upper Cretaceous to late Tertiary age. A deep suture zone, recognised in between these two fields and the associated faults provide channels for the upward migration of the thermal fluids. High concentrations of Cl, F, Si02, B, Na, Li, Rb, Cs in thermal fluids signify contribution of magmatic bodies towards heat, and fluid supply. These fields are characterized by high heat flow conditions (13 HFU), abnormal shallow geothermal gradients (0.7 - 2.5 c/m) , high base temperature (220 - 270 C) as obtained by alkalia and Ne-K-Ca geothermometry and low resistivity values (2-20 ohm.m.). Low resistivity zones occupy on an area of three and one sq.km. and extend down to maximum depths of 300 m. and 130 m. at Puga and Chumathang respectively. Shallow drilling (28-130 m.) has established the existence of wet steam reservoirs under moderate pressure (2-4.5 kg/cm^2). Hot fluid (95-135 C) discharges from eight flowing wells ranged from 7.5 to 30 t/h. These thermal fluids are stored in the partly consolidated fluvioglacial deposits of Quarternary to Recent age. The occurrence of a limestone layer in the country rock at Puga brightens the prospects of getting good reservoir at depth. In both these fields two aquifers have been recognised, each having sizeable potential for retaining ground water. The ground water recharge is mainly through snow melt from glaciers in the case of Puga field and principally from Indus river in the case of Chumathangfield Close

• 174. [Image] Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976

  	The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos ...
  	Citation × Citation Citation Abstract Copy Title: Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976 Author: West, F.G. (comp.) Year: 1977 The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos Scientific Laboratory (LASL), would utilize hydraulic fracturing to develop a large surface area in rock of low permeability, 10/sup -6/ darcys, and at temperatures greater than 200/sup 0/C. A better definition of the thermal regime in the crust and mantle at reconnaissance (hundreds to tens of kilometers) and exploration (tens of kilometers to 1 km) scales is needed. Geophysical methods capable of deep investigation would be used with the near-surface geologic information to extrapolate conditions at the depth of interest. Detection of HDR per se may be difficult because the contrast in physical properties of HDR and other rock is not always unambiguous, but boundaries between rock environments can be delineated. When patterns and coincidence of various types of geophysical anomalies and geologic maps are used, the probability of the detection of HDR is greatly increased, especially when a consistent picture is described. Various geophysical methods are required to detect these anomalies: (a) electromagnetic techniques can map deep electrically conductive structures, which to some extent can be used to infer isotherms. (b) Bouguer gravity maps corrected for regional topography are found to correlate with large silicic intrusive bodies, which are often associated with high heat flow. (c) isotherms and open crack systems at depth can be inferred from seismic wave attenuations, dispersions, and delay times. (d) heat flow measurements are useful as a primary tool and as a check on the results of other methods. Abstracts for individual presentations by the twelve panel members are included. 111 references Title: Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976 Author: West, F.G. (comp.) Year: 1977 The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos Scientific Laboratory (LASL), would utilize hydraulic fracturing to develop a large surface area in rock of low permeability, 10/sup -6/ darcys, and at temperatures greater than 200/sup 0/C. A better definition of the thermal regime in the crust and mantle at reconnaissance (hundreds to tens of kilometers) and exploration (tens of kilometers to 1 km) scales is needed. Geophysical methods capable of deep investigation would be used with the near-surface geologic information to extrapolate conditions at the depth of interest. Detection of HDR per se may be difficult because the contrast in physical properties of HDR and other rock is not always unambiguous, but boundaries between rock environments can be delineated. When patterns and coincidence of various types of geophysical anomalies and geologic maps are used, the probability of the detection of HDR is greatly increased, especially when a consistent picture is described. Various geophysical methods are required to detect these anomalies: (a) electromagnetic techniques can map deep electrically conductive structures, which to some extent can be used to infer isotherms. (b) Bouguer gravity maps corrected for regional topography are found to correlate with large silicic intrusive bodies, which are often associated with high heat flow. (c) isotherms and open crack systems at depth can be inferred from seismic wave attenuations, dispersions, and delay times. (d) heat flow measurements are useful as a primary tool and as a check on the results of other methods. Abstracts for individual presentations by the twelve panel members are included. 111 references Close

• 175. [Image] Geothermal Energy: Residential Space Heating

  	The purpose of this study, which was carried out under the auspices of the DGRST, was to determine the best way to use geothermal hot water for residential space heating. It quickly became apparent that ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Energy: Residential Space Heating Author: Delegation Generale a la Recherche Scientifique et Technique 35 rue Saint-Dominique, 75007 Paris Year: 1977 The purpose of this study, which was carried out under the auspices of the DGRST, was to determine the best way to use geothermal hot water for residential space heating. It quickly became apparent that the type of heating apparatus used in the housing units was most important and that heat pumps could be a valuable asset, making it possible to extract even more geothermal heat and thus substantially improve the cost benefit of the systems. Many factors play a significant role in this problem. Therefore, after a first stage devoted to analyzing the problem through a manual method which proved quite useful, the systematic consideration of all important aspects led us to use a computer to optimize solutions and process a large number of cases. The software used for this general study can also be used to work out particular cases: it is now available to any interested party through DGRST. This program makes it possible to: (1) take climatic conditions into account in a very detailed manner, including temperatures as well as insolation. 864 cases corresponding to 36 typical days divided into 24 hours each were chosen to represent the heating season. They make it possible to define the heating needs of any type of housing unit. (2) simulate and analyze the behavior in practice of a geothermal heating system when heat is extracted from the well by a simple heat exchanger. This simulation makes it possible to evaluate the respective qualities of various types of heating apparatus which can be used in homes. It also makes it possible to define the best control systems for the central system and substations and to assess quite accurately the presence of terminal controls, such as radiators with thermostatically controlled valves. (3) determine to what extent the addition of a heat pump makes it possible to improve the cost benefit of geothermal heating. When its average characteristics and heating use conditions (price, coefficient of performance, length of utilization, electrical rates, etc.) are taken into account, the heat pump should not be scaled for maximum heating power. Consequently, the program considers several possible sizes, with different installation schemes, and selects for each case the value which corresponds to the lowest cost of heating Title: Geothermal Energy: Residential Space Heating Author: Delegation Generale a la Recherche Scientifique et Technique 35 rue Saint-Dominique, 75007 Paris Year: 1977 The purpose of this study, which was carried out under the auspices of the DGRST, was to determine the best way to use geothermal hot water for residential space heating. It quickly became apparent that the type of heating apparatus used in the housing units was most important and that heat pumps could be a valuable asset, making it possible to extract even more geothermal heat and thus substantially improve the cost benefit of the systems. Many factors play a significant role in this problem. Therefore, after a first stage devoted to analyzing the problem through a manual method which proved quite useful, the systematic consideration of all important aspects led us to use a computer to optimize solutions and process a large number of cases. The software used for this general study can also be used to work out particular cases: it is now available to any interested party through DGRST. This program makes it possible to: (1) take climatic conditions into account in a very detailed manner, including temperatures as well as insolation. 864 cases corresponding to 36 typical days divided into 24 hours each were chosen to represent the heating season. They make it possible to define the heating needs of any type of housing unit. (2) simulate and analyze the behavior in practice of a geothermal heating system when heat is extracted from the well by a simple heat exchanger. This simulation makes it possible to evaluate the respective qualities of various types of heating apparatus which can be used in homes. It also makes it possible to define the best control systems for the central system and substations and to assess quite accurately the presence of terminal controls, such as radiators with thermostatically controlled valves. (3) determine to what extent the addition of a heat pump makes it possible to improve the cost benefit of geothermal heating. When its average characteristics and heating use conditions (price, coefficient of performance, length of utilization, electrical rates, etc.) are taken into account, the heat pump should not be scaled for maximum heating power. Consequently, the program considers several possible sizes, with different installation schemes, and selects for each case the value which corresponds to the lowest cost of heating Close

• 176. [Image] Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1

  	The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the ...
  	Citation × Citation Citation Abstract Copy Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Title: Petrology of the Quaternary Volcanics of the Roosevelt KGRA, and Adjoining Area, Utah. Final Report, Volume 1 Author: Nash, W.P. Year: 1976 The Roosevelt KGRA (Known Geothermal Resource Area) located near Milford, Utah, is associated with a suite of quaternary silicic volcanics distributed for 15 km along the crest and western flank of the Mineral Mountains, a large tertiary granite batholith. The volcanics are high-silica rhyolites and occur as domes, flows and tuffs. Initial eruptions resulted in two flows of low viscosity, phenocryst-poor rhyolite. Later activity consisted of pyroclastic eruptions and the emplacement of at least 9 viscous domes. In addition to abundant glass the rhyolites contain alkali feldspar, plagioclase, biotite, iron-titanium oxides and small amounts of hornblende, allanite, apatite, zircon, sphene and topaz. Magmatic temperatures were about 700C and water fugacities ranged from 350 to 3450 bars. Based on water fugacity calculations it is concluded that there may have been one or more shallow magma chambers in the Mineral Range at depths of about 1.6 km. Close

• 177. [Image] Economic factors relevant for electric power produced from hot dry rock geothermal resources: a case study for the Fenton Hill, New Mexico, area

  	The case study described here concerns an HDR system which provides geothermal fluids for a hypothetical electric plant located in the Fenton Hill area in New Mexico's Jemez Mountains. Primary concern ...
  	Citation × Citation Citation Abstract Copy Title: Economic factors relevant for electric power produced from hot dry rock geothermal resources: a case study for the Fenton Hill, New Mexico, area Author: Cummings, R.G Year: 1979 The case study described here concerns an HDR system which provides geothermal fluids for a hypothetical electric plant located in the Fenton Hill area in New Mexico's Jemez Mountains. Primary concern is focused on the implications of differing drilling conditions, as reflected by costs, and differing risk environments for the potential commercialization of an HDR system. Drilling costs for best, medium and worst drilling conditions are taken from a recent study of drilling costs for HDR systems. Differing risk environments are represented by differing rate-of-return requirements on stocks and interest on bonds which the HDR system is assumed to pay; rate of return/interest combinations considered are 6%/3%, 9%/6%, 12%/9% and 15%/12%. The method of analysis used here is that of determining the minimum busbar cost for electricity for this case study wherein all costs are expressed in annual equivalent terms. The minimum cost design for the electric generating plant is determined jointly with the minimum cost design for the HDR system. The interdependence between minimum cost designs for the plant and HDR system is given specific attention; the optimum design temperature for the plant is shown here to be lower than one might expect for conventional power plants - in the range 225/sup 0/ to 265/sup 0/C. Major results from the analyses of HDR-produced electricity in the Fenton Hill area are as follows. With real, inflation-free debt/equity rates of 6% and 9%, respectively, the minimum busbar cost is shown to lie in the range 18 to 29 mills/kwh. When real debt/equity rates rise to 12% and 15%, busbar costs rise to 24 to 39 mills/kwh.; DOE/ET/27017-T1 Title: Economic factors relevant for electric power produced from hot dry rock geothermal resources: a case study for the Fenton Hill, New Mexico, area Author: Cummings, R.G Year: 1979 The case study described here concerns an HDR system which provides geothermal fluids for a hypothetical electric plant located in the Fenton Hill area in New Mexico's Jemez Mountains. Primary concern is focused on the implications of differing drilling conditions, as reflected by costs, and differing risk environments for the potential commercialization of an HDR system. Drilling costs for best, medium and worst drilling conditions are taken from a recent study of drilling costs for HDR systems. Differing risk environments are represented by differing rate-of-return requirements on stocks and interest on bonds which the HDR system is assumed to pay; rate of return/interest combinations considered are 6%/3%, 9%/6%, 12%/9% and 15%/12%. The method of analysis used here is that of determining the minimum busbar cost for electricity for this case study wherein all costs are expressed in annual equivalent terms. The minimum cost design for the electric generating plant is determined jointly with the minimum cost design for the HDR system. The interdependence between minimum cost designs for the plant and HDR system is given specific attention; the optimum design temperature for the plant is shown here to be lower than one might expect for conventional power plants - in the range 225/sup 0/ to 265/sup 0/C. Major results from the analyses of HDR-produced electricity in the Fenton Hill area are as follows. With real, inflation-free debt/equity rates of 6% and 9%, respectively, the minimum busbar cost is shown to lie in the range 18 to 29 mills/kwh. When real debt/equity rates rise to 12% and 15%, busbar costs rise to 24 to 39 mills/kwh.; DOE/ET/27017-T1 Close

• 178. [Image] Beneficial Uses of Geothermal Energy Description and Preliminary Results for Phase 1 of the Raft River Irrigation Experiment

  	The first phase of an experiment using geothermal water for irrigation is described and preliminary results are discussed. The water was from a moderate temperature well, having salinity of about 2000 ...
  	Citation × Citation Citation Abstract Copy Title: Beneficial Uses of Geothermal Energy Description and Preliminary Results for Phase 1 of the Raft River Irrigation Experiment Author: Schmitt, R.C. Year: 1977 The first phase of an experiment using geothermal water for irrigation is described and preliminary results are discussed. The water was from a moderate temperature well, having salinity of about 2000 ppM, and is considered characteristic of the types of geothermal fluids that will be obtained from the young volcanic/young sediment formations of the northern intermountain west. The activity was completed at a location adjacent to ERDA's Raft River Geothermal Project in southern Idaho. About 12.5 acres, of which part had no previous cultivation, were subdivided by crops and irrigation practices for investigation with the geothermal water and a control comparison water from the relatively pure Raft River. Flood and sprinkler application techniques were used and wheat, barley, oats, grasses, alfalfa, potatoes, and garden vegetables were successfully grown. An accompanying experiment evaluated the behavior of an established alfalfa crop located nearby, when most of the irrigation water was geothermal. The experiment addressed heavy metal uptake in plants, plant fluoride retention and damage, plant tolerances to salts, soil alterations and other behavior as a result of the geothermal fluids, all of which were largely believed to eliminate geothermal water from contention for crop growing utilization. Not all analyses and results are complete in this reporting, but first results indicate no apparent difference between the geothermal watered crops and those obtained using the fresh water control. Extensive chemical analyses, neutron activation analyses, and other evaluations of crop samples are discussed, and some of the findings are presented. Although evaluation of crop yields was not an objective, extrapolations from samples indicate that yield results were comparable to those commonly found in the area, and the yield varied little between water sources. (JGB) Title: Beneficial Uses of Geothermal Energy Description and Preliminary Results for Phase 1 of the Raft River Irrigation Experiment Author: Schmitt, R.C. Year: 1977 The first phase of an experiment using geothermal water for irrigation is described and preliminary results are discussed. The water was from a moderate temperature well, having salinity of about 2000 ppM, and is considered characteristic of the types of geothermal fluids that will be obtained from the young volcanic/young sediment formations of the northern intermountain west. The activity was completed at a location adjacent to ERDA's Raft River Geothermal Project in southern Idaho. About 12.5 acres, of which part had no previous cultivation, were subdivided by crops and irrigation practices for investigation with the geothermal water and a control comparison water from the relatively pure Raft River. Flood and sprinkler application techniques were used and wheat, barley, oats, grasses, alfalfa, potatoes, and garden vegetables were successfully grown. An accompanying experiment evaluated the behavior of an established alfalfa crop located nearby, when most of the irrigation water was geothermal. The experiment addressed heavy metal uptake in plants, plant fluoride retention and damage, plant tolerances to salts, soil alterations and other behavior as a result of the geothermal fluids, all of which were largely believed to eliminate geothermal water from contention for crop growing utilization. Not all analyses and results are complete in this reporting, but first results indicate no apparent difference between the geothermal watered crops and those obtained using the fresh water control. Extensive chemical analyses, neutron activation analyses, and other evaluations of crop samples are discussed, and some of the findings are presented. Although evaluation of crop yields was not an objective, extrapolations from samples indicate that yield results were comparable to those commonly found in the area, and the yield varied little between water sources. (JGB) Close

• 179. [Image] Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems

  	Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems Author: Geonomics, Inc. Year: 1978 Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, fluid phase and composition, resource base and status of development. The subsurface environmental assessment evaluates potential groundwater degradation, seismicity and subsidence. A general discussion on geothermal systems, pollution potential, chemical characteristics of geothermal fluids and environmental effects of geothermal water pollutants is presented as background material. For the Imperial Valley, all publicly available water quality and location data for geothermal and nongeothermal wells in and near the East Mesa, Salton Sea, Heber, Brawley, Dunes and Glamis KGRAs have been compiled and plotted. The geothermal fluids which will be reinjected range in salinity from a few thousand to more than a quarter million ppm. Although Imperial Valley is a major agricultural center, groundwater use in and near most of these KGRAs is minimal. Extensive seismicity and subsidence monitoring networks have been established in this area of high natural seismicity and subsidence. The vapor-dominated geysers geothermal field is the largest electricity producer in the world. Groundwater in this mountainous region flows with poor hydraulic continuity in fractured rock. Ground and surface water quality is generally good, but high boron concentrations in hot springs and geothermal effluents is of significant concern; however, spent condensate is reinjected. High microearthquake activity is noted around the geothermal reservoir and potential subsidence effects are considered minimal. In Klamath Falls, geothermal fluids up to 113 C (235 F) are used for space heating, mostly through downhole heat exchangers with only minor, relatively benign, geothermal fluid being produced at the surface. Seismicity is low and is not expected to increase. Subsidence is not recognized. Of all geothermal occurrences in the Rio Grande Rift, the Valles Caldera is currently of primary interest. injection of geothermal effluent from hydrothermal production Wells should remove any hydrologic hazard due to some potentially noxious constituents. Waters circulating in the LASL Hot Dry Rock experiment are potable. Seismic effects are expected to be minimal. Subsidence effects could develop Title: Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems Author: Geonomics, Inc. Year: 1978 Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, fluid phase and composition, resource base and status of development. The subsurface environmental assessment evaluates potential groundwater degradation, seismicity and subsidence. A general discussion on geothermal systems, pollution potential, chemical characteristics of geothermal fluids and environmental effects of geothermal water pollutants is presented as background material. For the Imperial Valley, all publicly available water quality and location data for geothermal and nongeothermal wells in and near the East Mesa, Salton Sea, Heber, Brawley, Dunes and Glamis KGRAs have been compiled and plotted. The geothermal fluids which will be reinjected range in salinity from a few thousand to more than a quarter million ppm. Although Imperial Valley is a major agricultural center, groundwater use in and near most of these KGRAs is minimal. Extensive seismicity and subsidence monitoring networks have been established in this area of high natural seismicity and subsidence. The vapor-dominated geysers geothermal field is the largest electricity producer in the world. Groundwater in this mountainous region flows with poor hydraulic continuity in fractured rock. Ground and surface water quality is generally good, but high boron concentrations in hot springs and geothermal effluents is of significant concern; however, spent condensate is reinjected. High microearthquake activity is noted around the geothermal reservoir and potential subsidence effects are considered minimal. In Klamath Falls, geothermal fluids up to 113 C (235 F) are used for space heating, mostly through downhole heat exchangers with only minor, relatively benign, geothermal fluid being produced at the surface. Seismicity is low and is not expected to increase. Subsidence is not recognized. Of all geothermal occurrences in the Rio Grande Rift, the Valles Caldera is currently of primary interest. injection of geothermal effluent from hydrothermal production Wells should remove any hydrologic hazard due to some potentially noxious constituents. Waters circulating in the LASL Hot Dry Rock experiment are potable. Seismic effects are expected to be minimal. Subsidence effects could develop Close