The U.S. Army Corps of Engineers Sacramento District is moving forward with the Folsom Dam Raise Project to help further reduce flood risk in the Greater Sacramento area.  The overall project includes the following authorized components: a three-and-a-half foot raise of the Folsom Facility dikes, Mormon Island Auxiliary Dam (MIAD), Left Wing Dam (LWD), and Right Wing Dam (RWD), along with modifications to the main dam’s Tainter gates; construction of automated temperature control shutters at the main dam to benefit American River fisheries, and; habitat restoration at two sites along the lower American River - Bushy Lake Restoration Site and Woodlake Restoration Site.  The overall project also included construction of the Folsom Dam Bridge, which was completed in 2009.

The Dam Raise Project has prioritized completion of the remaining flood risk reduction elements of the overall project, which include raising the existing crest elevation of Dikes 1 through 8, MIAD, LWD, and RWD by approximately 3.5 feet, plus various structural changes to Folsom Dam (primarily modifications to the Tainter gates situated near the crest of the dam).  This work is expected to enhance utilization of Folsom Lake’s existing surcharge flood storage space and increase the temporary water storage space that can be used during flood events.

The Corps, in coordination with the California Central Valley Flood Protection Board and the Sacramento Area Flood Control Agency, has prepared a joint Supplemental Environmental Impact Statement/Environmental Impact Report (SEIS/EIR) for the flood risk reduction elements of the Dam Raise Project mentioned above.  The draft SEIS/EIR was first released for public review in July 2016.  This version of the SEIS/EIR underwent substantial revisions following the original review period.  The revised draft SEIS/EIR was released for public review in June 2017. The Corps released the final SEIS-EIR in October 2017. The record of decision was signed in December 2017.