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• 1. [Image] Feasibility of a Geothermal Heating System for Oakridge, Oregon

  	Geological and geophysical data indicate that Oakridge is underlain by geothermal waters. The strongest evidence is from the geothermal gradient, the increase of temperature with depth, in a 400' well ...
  	Citation × Citation Citation Abstract Copy Title: Feasibility of a Geothermal Heating System for Oakridge, Oregon Author: Bowen, R.C. Year: 1979 Geological and geophysical data indicate that Oakridge is underlain by geothermal waters. The strongest evidence is from the geothermal gradient, the increase of temperature with depth, in a 400' well on the south edge of the City. Although this well shows signs of disturbance by ground water, the geothermal gradient appears to be similar to the gradient from a well near McCredie Hot Springs seven miles to the east. Additional evidence is a salt spring, just south of the City, that may represent a fossil geothermal system that has become sealed and is no longer flowing hot water. A third line of direct evidence is the presence of a warm spring about three miles southeast of the City that is now covered by Hills Creek Reservoir. Indirect geophysical evidence is a high gravity gradient from west to east near Oakridge. This gradient relates closely to the region of increasing geothermal gradient and heat flow of the Cascade Geothermal Anomaly. Indications of intersection of regional fault patterns could provide the subsurface fracturing and permeability necessary for a geothermal reservoir. The results of this study indicate that water sufficiently hot to be useful can be located by drilling to depths of three to four thousand feet at Oakridge. Three sites are proposed for shallow geothermal gradient holes to test the proposed model. Title: Feasibility of a Geothermal Heating System for Oakridge, Oregon Author: Bowen, R.C. Year: 1979 Geological and geophysical data indicate that Oakridge is underlain by geothermal waters. The strongest evidence is from the geothermal gradient, the increase of temperature with depth, in a 400' well on the south edge of the City. Although this well shows signs of disturbance by ground water, the geothermal gradient appears to be similar to the gradient from a well near McCredie Hot Springs seven miles to the east. Additional evidence is a salt spring, just south of the City, that may represent a fossil geothermal system that has become sealed and is no longer flowing hot water. A third line of direct evidence is the presence of a warm spring about three miles southeast of the City that is now covered by Hills Creek Reservoir. Indirect geophysical evidence is a high gravity gradient from west to east near Oakridge. This gradient relates closely to the region of increasing geothermal gradient and heat flow of the Cascade Geothermal Anomaly. Indications of intersection of regional fault patterns could provide the subsurface fracturing and permeability necessary for a geothermal reservoir. The results of this study indicate that water sufficiently hot to be useful can be located by drilling to depths of three to four thousand feet at Oakridge. Three sites are proposed for shallow geothermal gradient holes to test the proposed model. Close