Schuster and Bloomquist (1994) have compiled a resource database which includes 975 thermal wells and spring, an increase of 165% over the number of entries reported in 1981. Most of the thermal springs occur in the Cascade Range , associated with stratovolcanoes. In contrast 97% of the thermal wells are located in the Columbia Basin of southeastern Washington. These thermal wells are strongly associated with the Columbia River Basalt Group and the Columbia Basin. Rather than prioritize limited areas within this region for detailed studies, Schuster and Bloomquist (1994) make three recommendations for greatly expanding geothermal use in the state. The recommendations are: (1) match existing thermal wells with proposed retrofit or new construction, (2) measure temperature gradients, obtain well-test data and drill cuttings, and collect water samples for chemical analysis, and (3) inform state residents and policy makers about uses of geothermal energy.
Schuster, J. E. and R. G. Bloomquist, 1994. Low-Temperature Geothermal Resources of Washington, Washington Division of Geology and Earth Resources Open-File Report 94-11, 53 p.