Lincoln County & Walla Walla - broad & thin 165 square mile geothermal field
With a temperature of 105F (41C) this field is a mere 300 feet thick, and covers 165 square miles around Walla Walla. This resource offers a net thermal potential of 57MWth. However the data is largely reliant on shallow boreholes. The Davenport reference below refers to the heat gradient, not the temperature measured. However, high heat gradients are excellent indicators. It is important to note that these wells are shallow, limiting confidence.
In Lincoln County, an area which extends 50 km west from Davenport contains many wells with good quality gradients ranging from 50 to 6OC/km. Most of the wells are less than 750 meters deep, and very little information is available on the temperature and production of the aquifers within the anomaly. The same could he said of the anomaly in Douglas County, where a few wells suggest above normal gradients.