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Major Accomplishments: Folsom Dam Improvements

interactive image:  photo - A view looking up into the auxiliary spillway; click for larger photo
A view looking up into the auxiliary spillway.

The Bureau of Reclamation and federal, state and local agency partners continued a unique partnership to further protect more than a million residents in communities downstream from Folsom Reservoir. Numerous construction projects were either begun or completed in 2010 to improve flood protection and reduce dam safety risks at the Folsom facility on the lower American River, about 25 miles northeast of Sacramento.

The projects, and pending projects, represent more than $1 billion in improvements.

Reclamation’s partners in the projects are the Army Corps of Engineers, the Sacramento Area Flood Control Agency and the state of California.

Michael Finnegan, manager of the Mid-Pacific Region’s Central California Area Office, which includes Folsom Dam and Reservoir, said, “The cornerstone for these efforts is the Joint Federal Project, which includes a new auxiliary spillway consisting of a control structure, a 1,000-yard lined spillway chute, a 370-yard approach channel and a stilling basin.”

Mr. Finnegan said the Region completed the second of its two phases for the Project in 2010. Together, the phases involved excavation of nearly 2 million cubic yards of material from the spillway chute, construction of an in-reservoir haul route and relocation of a water service pipeline serving the City of Folsom and Folsom State Prison. The Region completed its portion of the Project on schedule and at about $60 million less than the original government estimate. Construction at the spillway site is now being transferred to the Corps for the third phase of the project.

interactive image:  photo - An artist’s rendering that depicts the appearance of the auxiliary spillway when it is completed at Folsom Dam; click for large photo
An artist’s rendering that depicts the appearance of the auxiliary spillway when it is completed at Folsom Dam.
interactive image:  photo - Water released into the new auxiliary spillway, shown at the top, will flow into the American River in the foreground; click for larger photo
Water released into the new auxiliary spillway, shown at the top, will flow into the American River in the foreground.

During 2010, the Region also completed improvements to Dikes 4 and 6, and awarded a $35 million contract to excavate foundation material along a 1,000-foot section at Mormon Island Auxiliary Dam and replace it with special fill material. The contract, and follow-up work to overlay the downstream face of the dam, address a long-standing seismic risk concern. The Region expedited award of a $17 million contract to replace five service gates and three emergency spillway gates, as well as perform bracing and other work to mitigate a seismic risk to the main concrete structure. The work was funded under the American Recovery and Reinvestment Act of 2009.

The Region also began an extensive overhaul of the three generators at the hydroelectric powerplant at the Folsom facility. The $44 million overhaul is expected to be completed over the next three years. Generation from the plant is roughly an amount that would meet 15 percent of the demand for the greater Sacramento metropolitan region.

More information can be found at http://www.usbr.gov/mp/jfp/.

interactive image:  photo - Contractors disassemble part of the equipment related to the hydroelectric power plant at Folsom Dam; click for larger photo
interactive image:  photo - Contractors build an access road to the new auxiliary spillway, with a new pipeline shown at left; click for larger photo
interactive image:  photo - View of upper auxiliary spillway, expanded overlook area, and Natoma pipeline bridge in the foreground; click for larger photo
Contractors disassemble part of the equipment related to the hydroelectric power plant at Folsom Dam. Contractors build an access road to the new auxiliary spillway, with a new pipeline shown at left. View of upper auxiliary spillway, expanded overlook area, and Natoma pipeline bridge in the foreground.
interactive image:  photo - Contractors remove a turbine bearing as part of the hydroelectric plant overhaul; click for larger photo
interactive image:  photo - A view of the lower stilling basin access road and cofferdam wall; click for larger photo
interactive image:  photo - View of a temporary cofferdam nearing completion; click for larger photo
Contractors remove a turbine bearing as part of the hydroelectric plant overhaul. A view of the lower stilling basin access road and cofferdam wall. View of a temporary cofferdam nearing completion.

March 31, 2011