The US Bureau of Reclamation (USBR) is conducting geological investigations at the potential site of the Black Rock dam, 40km east of Yakima, Washington.
Investigations started on 22 November and are expected to be completed in Spring 2006. Work involves drilling two holes, one at each end of the dam site, both about 137m to 183m in depth.
The work is needed to define the extent of the underground Black Rock Valley fault, and to assess information about possible seepage at the potential dam’s foundation and possible leakage along the valley walls where the reservoir would be situated. Core samples collected during the test drilling will also be used to assess the depth of excavation needed for a suitable foundation for the dam.
The project is part of USBR’s Yakima River Basin Water Storage Feasibility Study.