A federal leader last week mentioned a study to raise San Luis Dam and expand the nearly empty San Luis Reservoir in western Merced County, raising eyebrows all around. Why study expansion of a reservoir holding 16% of its capacity? And why now?
First, a little context. San Luis Reservoir is an important hub in California’s waterworks — supplying both west San Joaquin Valley farmers and Southern California cities. The reservoir has no natural stream to fill it, so water is pumped there from the sensitive Sacramento-San Joaquin River Delta.
When pumping was restricted this year to protect dying fish species and water quality, California lost the opportunity to send a lot of water into the reservoir. The lost pumping and the drought have turned the reservoir into an August mud puddle.
So why look at expanding San Luis Reservoir now?
Half of the answer: It’s part of the ongoing efforts under the Central Valley Project Improvement Act, a 1992 environmental reform law that includes a section to improve water supply.
The other half: The U.S. Bureau of Reclamation is going through a dam safety study. The planning division is appraising a project to both reduce earthquake risks and improve deliveries to the federal Central Valley Project.
At the same time apparently, water customers began asking about expanding the capacity of the reservoir.
By sometime next year, the appraisal study will let federal leaders know if they should do a full-blown feasibility study.
This is all part of a bigger fight, pitting Northern California against Southern California over water. It’s a story that has played out over decades. Another chapter is about to be finished as the state prepares the Bay Delta Conservation Plan, touted as a way to fix this marathon problem. It’s a nerve-racking process.
The short-term solution makes everyone even more nervous: Hoping for a wet winter. This problem could get much worse if California gets a third year of drought.