ENGINEERING GEOLOGY OF THE HIGH SAVERY DAM SITE, CARBON COUNTY, WYOMING
Localized open fissures were encountered in the Browns Park Formation in the upper portion of both abutments. Two high permeability fracture zones were identified in the sandstone in the valley foundation and lower abutments. These fracture zones represent seepage pathways in the dam foundation. Low permeability bentonitic clay beds dip in the downstream direction and provide for potential slope/foundation failures and were a key issue in design of the embankment, primary spillway, and temporary cut slopes. The lower high-permeability fracture zone in the valley is also confined by one of the low permeability clay beds. This fracture zone would transmit high pore pressures to this weak, bentonitic clay bed. Landslide deposits were identified underlying the proposed inclined intake structure, and immediately adjacent to the primary spillway chute and stilling basin. The geotechnical design team used the results of the engineering geologic investigation to develop appropriate design elements to address each of these seepage and stability issues.