Things are also complicated by mixing up of the CSWP (1960s), with the Central valley project [1], CVP which is older (1930s). If you browse through the timeline, you will see a lot of detail about funding secured for irrigation, and trading farmers water rights for rights for canal water. This Wikipedia page has some fascinating detail on the history.[1] This image shows the CVP which was built to serve farmers, and the later addition by the SDWP to connect with urban users in southern California.[2] Today I learned that the project was initially intended to limit users to small farmers 160 acres or less (1 Mi^2). Imagine how different California would look if that were the case.

I just found the wiki page today and it is one of the best and most technical pages I have seen in a long time, probably ever. It has lists of relevant annual reports going back to the 1920s, a comprehensive list of litigation, and tons of relevant links.

I also found a reference to farmers being advised to avoid orchards, but this pertained to the CSWP waters from the 1970s onward [3]

>In the early 1970s, the SWP system still had a lot of "surplus" – water supply developed through the construction of Oroville Dam, which was running unused to the Pacific Ocean because the water delivery infrastructure for Southern California had not yet been completed (and when it was, southern California was slow to use the water). The surplus water was given for irrigation in the San Joaquin Valley instead. Because the water would only be a temporary supply, farmers were advised to use it for seasonal crops (such as alfalfa or hay) rather than permanent crops such as orchards. Nevertheless, many farmers used the water to develop new permanent crops, creating a dependency on SWP water that is technically part of Southern California's entitlement

On a different perhaps more mixed note, I found these articles [4][5] going down this rabbit hole of "permanent water contracts"

>According to the Bureau of Reclamation, as of October 2019 more than 75 agencies that had “temporary” water service contracts to receive Central Valley Project water, including the State of California Department of Fish and Wildlife, have exercised the option provided by the WIIN Act to convert their contracts to “permanent” repayment contracts. The contract terms proposed in the repayment contracts for Westlands and other Central Valley Project contractors under the WIIN Act are nearly identical to those in the Friant Division repayment contracts.

>The Interior Department on Friday awarded the nation’s largest farm water district a permanent entitlement to annual irrigation deliveries that amount to roughly twice as much water as the nearly 4 million residents of Los Angeles use in a year....The district is one of more than 75 Central Valley Project customers — most of them farm irrigation districts — that are taking advantage of a 2016 law to convert water service contracts that require periodic renewal to agreements that permanently lock in delivery entitlements and other terms.

I believe these are the water contracts that farmers have been paying since the 1930s, which had terms to convert to
permanent contracts. I will have to tell my republican farming family how Obama accelerated the terms of the water contracts to make them permanent.

https://en.wikipedia.org/wiki/Central_Valley_Project

https://en.wikipedia.org/wiki/Central_Valley_Project#/media/...

https://en.wikipedia.org/wiki/California_State_Water_Project

http://redgreenandblue.org/2020/02/29/californias-westlands-...

https://www.latimes.com/environment/story/2020-02-28/westlan...