Hardfill Dam Feasibility in a High Seismic Area

A hardfill dam is a variation of RCC that distinguishes itself by utilizing on-site aggregate in its natural state, without the need for any additional treatment except for the removal of large particles. The feasibility of a 300-foot high hardfill dam was evaluated for a site located in California with relatively high seismicity. Several hardfill dams with heights up to 500 feet have been constructed around the world since the late 1980’s, including in areas of high seismicity. The foundation was judged adequate to support the dam and the rock quality was good enough to provide hardfill aggregate. No active faults were identified at or close to the dam site. Based on the results from investigation and design analyses using linear and nonlinear methods, the hardfill dam was concluded to be a technically feasible dam for the proposed site. The eventual decision not to proceed with the hardfill dam considered the lack of precedent for this dam type in California. This paper will discuss potential next steps designers and dam safety regulators could take to construct a hardfill dam in highly seismic areas.