Operational Success of Highly Innovative Diversion With Fish and Recreational Passage On the American River At the Former Auburn Dam Site

Construction of the Auburn Dam was halted in 1975 when a seismic fault was discovered.  The site languished for the next several decades and the site was even overtopped by a major flood.  The flood partially destroyed the 300 foot-high coffer dam, sending hundreds of thousands of tons of debris and earth into the river below.   Over the following decades, the Placer County Water Agency continued to use a temporary replacement diversion to perform the function of a permanent diversion that was destroyed by the construction of the dam.   To facilitate implementation of a new permanent diversion, whitewater boating and fish passage elements were included in the design.   The new diversion was the first to implement a new (and patented) “Chute Screen” which provides a self-cleaning fish screen located in the invert of a man-made “rapid”.  Since start-up in 2008, the diversion and intake screen have worked very well.   The screen and structures have survived flood events, high sediment loadings, and have not required cleaning of the screens.  Furthermore no damage to the screens has occurred. The project won the 2010 ASCE-CA Project Of The Year.  An overview of the design objectives, design, and operation history are the focus of this paper.