> Collection of rainwater is never an option in farming.
I used to be a Farm Manager, and did a 3 year apprenticeship in Biodyniamic Ag.
I know of very few crops that can remain fallow/non-irrigated and still do well come harvest, they exist but are hardly going to be widespread much less in AZ. And while there are practices that can be undertaken to conserve water (cover crops, large scale mulching, drip irrigation) all of which I have personal experience in utilizing, this was more about how to ensure the barrier of entry is excluded to those who would otherwise just deplete it in a tragedy of the commons manner.
Let me explain in more detail.
My idea was based on the following: to initially access the aquifer you must install another metered pump that must remain in operation and re-pump an equal amount that you pumped out of the table in earlier seasons throughout the year/season back into the source and failing to return it will not just incur costs/penalties but also deny you access to it.
When I was a Farm manager in Maui we had a similar issue with nearby dry land Taro growers, as a Biodynamic farm we have more active cultures with various water needs, so we had a large reservoir (20000 gallon capacity tank attached to a sand sand based filtration system) that ensured we could remain operational for extended periods of time of drought as we captured rain water as a ritual, but we could also replenish the source if need-be and often did to purge and clean the tanks. They can get moldy due to stagnation, and water is very important in Biodynamics, specifically that which if it is perturbed--its mainly just for water aeration.
The water source we captured from was a creek that came from Haleakala and was gravity fed to our cultures so it was considered sacred, and we were Haoles so we always had to make an even greater effort to maintain good relations with our Native neighbors. Nothing was ever good enough, but we did it anyway.
That meant fixing their neglected or poorly built dams/jetty, and offsetting their water needs when Maui electric shut off the water sources for maintenance and went way longer then they projected (Welcome to Hawaii!).
I lost all of my greenhouse starters so that our neighbors could have water that season and have something to bring to Market and I emptied my tank several times to do so and had to get creative about how I'd water my other active cultures with rain water and had to make due to continue to bring product to Market in order to keep our 1:1 profit sharing model with our vendors/produce managers.
We would was always be seen as foreigners taking resources, despite having been the only Farm on the Islands to take in people with special needs as part of our Program (Camphill), who we built an Art Studio for and then bought a large Home for that took money from our Ag program I was supposed to be managing. And after many 70+ work weeks we finally made them profitable for the first time in their entire existence proving the model can work, but requires EXTENSIVE amounts of hard-work, dedication, and sacrifice.
We often gave away any excess food we couldn't sell or had on hand after we fed our staff to the local food bank. I lost money that year as I had to stop getting paid after my 7th month there, and I often had to fight the Department of Ag in audits so much that I just paid out of pocket to finish the irrigation system myself.
I also made an effort to hire local people, of all colours, rather than my initial desire to take on European applicants who were already trained and I could take them on as non-paid apprentices working the 40+ work weeks, as I had.
I realized it was a lost-cause and that racism/exclusion is prevalent and cannot work due to issues that extend far before my Time there, so I resigned and left on a high (despite massive burn-out) only to be given an affirmation of Pono as I left from Maui.
The point is that collaboration with your neighbors is far more important than any water conserving or well mentioned actions ever will be. And that is how this how sustainability should be approached.
Because the truth is, Nestle has been doing this for some time, some large Multi-national could just show up buy the source, deplete what was there and then walk away and use the losses as a tax write-off. Then come back and buy back all the surrounding area in distress for cheap and recover any costs and hold it in their portfolio as assets to leverage in some other capacity.