Geothermal investigations in Idaho: Geothermal resource analysis in Twin Falls County, Idaho:

Increased utilization of the geothermal resource in the Twin Falls - Banbury area of southern Idaho has resulted in noticeable declines in the artesian head of the system. In order to determine the nature of the declines, a network of wells was identified for monitoring shut-in pressures and temperatures. In addition, a compilation of data and reconnaissance of the areal geology was undertaken in order to better understand the geologic framework and its relationship to the occurrence of the thermal waters in the system. The results of the monitoring indicate that while water temperatures have remained constant, the system shows a gradual overall decline in artesian pressure superimposed on fluctuations caused by seasonal use of the system. Well testing and the similarity of hydrographs resulting from well monitoring throughout the area suggest that there are no major hydrologic barriers to thermal water movement in the system and that wells are affected by increases and decreases in utilization of nearby wells. 46 refs., 13 figs., 1 tab.