Oroville Flood Control Outlets and Folsom Auxiliary Spillway -How the Offspring Differs from the Parent

摘要

The recently completed Folsom Dam Auxiliary Spillway (FAS) consists of a reinforced concrete Control Structure that contains six (6) submerged Tainter gates that measure approximately 23 × 34 feet each, and a rectangular, reinforced concrete channel, stepped chute, and stilling basin that measure approximately 3,000 feet long. The initial design concepts for the FAS were patterned after the Oroville Dam Flood Control Outlet (FCO) spillway. The FAS is compared to the original FCO Control Structure and spillway to show how the two vary and where different site and operational conditions were taken into account for design of the FAS. Side by side comparisons of the two facilities are made that trace the important changes from initial FAS hydraulic physical modeling through design and final construction. Hydraulic, structural, mechanical, geotechnical, and geologic engineering efforts are described. This includes design aspects such as physical and numerical hydraulic modeling and important construction and specification details that are applicable to modern structures. In addition, the completion of the FAS in 2017 was a valuable aid to the FCO planners and engineers so that recently completed design and construction practices, particular to these types of complex structures, could be adapted and used quickly in the FCO reconstruction.