Anderson Dam: Owning a Dam Ain’t Cheap
The Santa Clara Valley Water District (Valley Water) supplies water to much of the San Francisco Bay Area’s “Silicon Valley,” with a good portion of its supply pumped from the Sacramento-San Joaquin Delta — plus a little gathered from local runoff.
Valley Water’s Anderson Dam lies astride Coyote Creek in Morgan Hill and impounds up to 91,300 acre-feet. But the dam turns out to have some seismic issues. That’s not a recipe for success so close to the San Andreas Fault and its nearby network of faults. In 2009, Valley Water began limiting the allowed reservoir levels to 75%, then over the next decade to 54%, then 68% to limit the risk of dam failure.
In 2020, the Federal Energy Regulatory Commission, one of the dam’s regulators, citing concerns that the District’s “actions to date do not demonstrate an appropriate sense of urgency” in addressing the seismic threat(1), ordered the reservoir evacuated down to dead pool(2). The dam would have to be reconstructed to use again, although since the power facilities will not continue, FERC’s oversight will end, leaving the job to the state of California(3).
The reconstruction turned out to be a $2.8-billion project. By now, some of that has been spent (for example, a new tunnel to evacuate the reservoir better), and the District just awarded a $1.88-billion-dollar contract to reconstruct the dam(4).
All that spending has caused some belt-tightening at the District. For example, it cancelled its nearly $3-billion Pacheco Dam project last year and caused some rate hikes.
You need some deep pockets to own a dam!
Resources
Mercury News – Feds order reservoir to be drained due to earthquake collapse risk
Gilroy Dispatch – Feds order draining of Anderson Reservoir
Valley Water – Key federal regulators approve the Anderson Dam Seismic Retrofit Project
Gilroy Dispatch - Valley Water awards nearly $2B construction contract for Anderson Dam retrofit
