Nukes are 10 GW, typically. Without seeing your post, I calculated it would take about 60 GW, i.e. 6 nukes, running all the time (which nukes do tend to do) to desalinate enough water to flood the entire state of CA to a depth of 1 foot in a year, though, not including pumping energy requirement. Less, of course, to only add a foot per year to the central valley rather than the whole state.
This is the largest nuclear reactor in the USA. Nowhere near 10,000 megawatts.
The Grand Gulf Nuclear Station in Port Gibson, Mississippi, has the largest U.S. nuclear reactor with an electricity generating capacity of about 1,400 MW.Apr 6, 2021
https://www.eia.gov/energyexplained/nuclear/us-nuclear-industry.php
There is not a single reactor parks with ten gigawatts. This is the largest park in the world.
Tokyo Electric Power Co.’s (TEPCO) Kashiwazaki-Kariwa plant in Japan is currently the world’s largest nuclear power plant, with a net capacity of 7,965MW. Kashiwazaki-Kariwa has seven boiling water reactors (BWR) with a gross installed capacity of 8,212MW.Jun 26, 2019
https://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/
Here are the top ten for the USA. The largest is Palo Verde with 3.9 GW that comes from three 1.33 GW individual reactors.
https://www.power-technology.com/features/the-biggest-nuclear-power-plants-in-the-us/
You are gonna need a lot more than 12 inches of water per square foot. Alfalfa the number one crop in California uses 4 to 5 feet water per square foot per year. UC Davis has decades of data. That one crop alone uses 5 million acre feet per year. Almonds use 1900+ gallons per lb of crop yield there is 325800 gallons to an acre foot look up the yield per acre of almonds then add up how much water that took. Rice which California grows a good bit of needs up to 6 acre feet per acre. Corn needs 2 to 3. California has too many acres under irrigated cultivation that’s just a fact. The Colorado River compact of 1922 was set with water rights for a period of unusual precipitation. How unusual levels that have not been seen.in 2000 years the compact was set for a water amount that has not been the norm since Jesus walked the earth. Read up on the history of the compact set aside a few hours of time it’s that comprehensive.
https://alfalfa.ucdavis.edu/%2Bsymposium/proceedings/2008/08-265.pdf
I guess I should have lead off with I have been a licenced PG and working professional geologist for more than two decades. One of my master’s is in hydrology and my PhD is directly related to hydrogeology. I also hold a master’s in petroleum geology. I have done extensive field work in the Colorado basin and sedimentary transport and depositional studies at lake mead. I was under contract from New Mexico to study water capture of various endemic species to determine the best way to keep water in the Rio Grande river and not in the riparian areas particularly Prosopsis and the very invasive Tamarisk. Water and oil are my bread and butter. Have been in both industries for decades.