Hydrothermal resources of western Colorado
— Richard H. Pearl

In Colorado west of the Continental Divide there are 34 thermal areas containing approximately 103 thermal springs and wells (fig. 1). The surface temperatures of the waters in these areas range from a low of 23°C to a high of 80°C. The temperatures, discharge, total dissolved solids and estimated reservoir temperatures of the thermal systems of western Colorado are summarized in Table 1.

 

The surface temperatures of the thermal waters found in western Colorado are not excessively hot as contrasted to such higher temperature geothermal systems as hot dry rock, geopressured, and dry steam found elsewhere in the western United States. Consequently the geothermal resources of Colorado are classified as hot-water hydrothermal resources.

 

The hydrogeological conditions and resources of the hydrothermal systems of western Colorado have been discussed by numerous authors. For a complete listing of all authors who have written on the thermal springs of western Colorado the reader is referred to the references at the end of this paper.

 

With one exception, Routt Hot Springs, north of Steamboat Springs, all thermal areas in western Colorado are geologically associated with sedimentary rocks. The geological conditions of the thermal areas vary from the relatively simple structural conditions at South Canyon Hot Springs, west of Glenwood Springs and Pagosa Springs in southwestern Colorado to the highly complex structural environment which exists at Rico and Ouray in southwestern Colorado. Evaluation of the geological conditions of each thermal area has shown that all thermal waters are associated with faults and in several instances the springs are located at the intersection of two faults. This is in agreement with geological controls of most thermal systems throughout the world.

 

The Colorado Geological Survey, with U.S. Department of En- ergy funding, is currently engaged in a limited exploration program to evaluate the following resource areas in western Colorado: Steamboat-Routt Hot Springs, Hot Sulphur Springs, Waunita Hot Springs, Cement Creek-Ranger Hot Springs, Ouray, the Animas Valley north of Durango and Wagon Wheel Gap Hot Springs. Upon completion of this program in 1982, reports will be available to interested parties, which will, as accurately as possible, depict the geological and hydrogeological characteristics of each system.