Work started last week on raising the B.F. Sisk Dam at San Luis Reservoir 10 feet to reduce the risk of the massive earthen structure collapsing in a major earthquake.
This comes after exploratory blasting began in spring 2020 at the reservoir adjacent to Highway 152 near Los Banos.
The federal project is expected to cost $1.1 billion and take nine years — even with crews working 24 hours a day beginning later this year. Altogether, more than 10 million cubic yards of rock, gravel, and soil will be moved from nearby hills to harden and raise the now 382-foot high dam.
But, with the drought increasing the need to expand water storage in big precipitation years for ag and urban users alike, some are asking, “Why not raise the dam 20 feet instead?”
10 More Feet Will Cost $1 Billion
That additional 10 feet would cost another $1 billion, and increase the reservoir’s capacity by 130,000 acre-feet. There are farmers and potentially interests in the Santa Clara Valley who might be willing to pay the freight.
Here is the link to the Bureau of Reclamation’s fact sheet about the project.