Abstract: The various components of inflow and outflow to and from the lake and their relative magnitudes were identified. In 1972 water year the total inflow to the lake was 200,000 acre-feet, but it was only 75,000 acre-feet in 1973 water year. In 1972 water year the Donner and Blitzen River contributed 55 percent of the inflow, with Silvies River, direct precipitation, and Sodhouse Spring contributing 28, 13, and 4 percent respectively. Om 1973 the Donner and Blitzen River contributed 61 percent of the inflow. The Silvies River, direct precipitation, and Sodhouse Spring contributed 1, 25, and 12 percent respectively. Ground-water inflow, other than Sodhouse Spring, appears to be negligible. In 1972 water year, 81 percent of the outflow was by evapotranspiration and 19 percent was surface outflow through The Narrows. In 1973, 96 percent of the outflow was by evapotranspiration and 4 percent was surface outflow through The Narrows. Ground-water outflow is negligible.

Purpose: This study was conducted in order to assess the character and extent of Tertiary volcanic rocks and volcanic-derived sedimentary rocks as potential uranium host and (or) source rocks.

Introduction: This report presents engineering details, statistics, individual borehole histories, and geophysical logs of the eleven holes drilled in the McDermitt caldera project during the 1981 drilling program. General information is presented regarding specific problems, including weather and logistics. A separate geologic report is being prepared and will be available through the Bendix Field Engineering Corporation Technical Library in the near future.

Supplementary data containing geophysical logs to accompany an engineering report on the McDermitt Caladera Drilling Project in Nevada and Oregon.

The following report is a guide that documents the geological features visible from or near Steens Mountain Loop Road, Harney County, Oregon.