RS-17 Geothermal Resource Assessment of the Animas Valley, Colorado

Geothermal assessment of the Animas Valley, Colorado. Includes geology, hydrogeology, geophysics, and geochemical resource assessment results. 60 pages. 19 figures. 9 tables. 6 appendices. Digital PDF download. RS-17D.

In the Animas Valley in southwestern Colorado, between 9 and 14 miles (15 and 23 km) north of Durango in La Plata County, there are two groups of thermal springs: Pinkerton Springs to the north, and Tripp-Trimble-Stratten Springs about 5 miles (8.1 km) south of Pinkerton. Temperatures range from 82 to 111°F (28 to 44°C), and discharge ranges from 1 to 50 gpm (0.06 to 3.15 l/s).

The geothermal resources in the Animas Valley are fault controlled. Pinkerton and Tripp-Trimble-Stratten Springs are probably not directly connected systems, but may have the same source at distance. Water recharge to the geothermal system comes from the Needle and La Plata Mountains, and the latter may also be a heat source. Movement of the thermal water is probably primarily horizontal, via the Leadville Limestone aquifer. Water quality data from these springs is included in the report appendix, along with an evaluation of soil mercury concentrations used to delineate faults or permeable zones.