Nah, thats just a completely revisionist history. All of these works projects were funded by federal dollars or city dollars, including the infrastructure to get it to the farmers. They pay a fraction of the delivery cost the cities pay. All the purification and recapture facilities are built and paid for on top of that. Western farmers have never, ever paid a fair price for the water they use.
That's bullshit, at least in California. Most of the problem water usage from Farmers, for example in the central and antelope valley, has been from private wells on private property they themselves sunk, or an equivalent small co-operative they were a member of did. They've been tapping huge underground fossil aquifers that way for nearly 100 years now, to the point it's been collapsing. No canals required. [https://en.wikipedia.org/wiki/Central_Valley_land_subsidence]
It's estimated the ground has permanently sunk ~ 28 ft. from this alone.
Before this started, the water table in the Antelope valley was at ground level in many places, with literal artesian springs popping up. It's now well over 2500 ft below ground level.
The Delta Mendota canal (finished in '51) was an extension and redo of a number of existing canals that were there far before. The army corp of engineers did a lot of the work then - but it wasn't that new. And this was all water just a few feet above sea-level and that would shortly become seawater if left unmolested.
Most of these original Canals from the Sierras existed before the concept of a state water organization existed. Some of them existed literally before the state did, and were from Spanish colonization/slavery. They weren't as mechanized or as large scale, but they were there.