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Montana Geothermal Sites: Alhambra
SUMMARY INFORMATION:
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| Location: N 46.4497 W 111.9805 Nearest town: Clancy County: Jefferson Depth: Spring Temperature: 56° C, 133° F Flow : 100.4 gpm, 380 L/min TDS : 909 (mg/L) Site ID: MGEOT001 LOCATE AND VIEW VIA NRIS DIGITAL MAPS: Allows access to resizing topos and aerial black & white images. |
CHEMISTRY (ppm, mg/L) Site name: ALHAMBRA Temp: 56.5 C TDS: 909.0 pH: 7.23 Sodium: 220.0 Potassium: 9.5 Calcium: 18.0 Magnesium: 3.5 Boron: 200.00 Lithium: 8.4 Boron: 200.00 SiO2: 66.00 Sulfate: 89.0 Chloride: 10.0 Fluoride: 8.4 |
There are two hot spring areas and four warm water wells at Alhambra with an average temperature of 56 C and a combined flow of 380 L/min. The water is currently used for space heating at a local nursing home.
The springs are privately owned, and no public bathing is allowed. Historically (1920-1950) the Alhambra hotel and medical facilities were a popular health resort destination.
In the 1920s the new Alhambra hotel became one of the favorite social gathering spots for Helena and Butte residents, with trains stopping several times a day. Alhambra mineral water was available onsite and sold by the bottle for its health benefits.
Chemical ratios indicate a reservoir temperature of 87-96° C at a depth of 1,000 meters (Sonderegger). Aerial heat sensing surveys in the late 1970’s indicates a NS fracture system controls the geothermal surface flow and that there are extensions of the known system and another warm water area. The system appears to be controlled by fracture permeability near high angle block faults.
The Alhambra system has been reviewed in several reports by the USGS and the Montana Bureau of Mines. Leonard, R (1978) studied the system in relative detail, other reports include Leonard-Janser (1978), Vice, D. MBMG OF-98, Galloway (1977), and Sondregger (1983) MBMG OFR 142.
