Something like 80% of the water sucked out of the Colorado River watershed goes to agriculture, and a lot of that is for hayfields.

If soil carbon levels were brought back to healthy levels, it has been estimated that agricultural irrigation water use could be reduced by 50%. 50% of 80% is 40%. If humans weren't butt stupid we could use excess biomass (and there is a humongous lot of it) to use in making cheap energy and biochar, and use the biochar in ag soils, which would increase the Colorado Basin water supply by a whopping 40% while reducing catastrophic wildfires, increasing soil productivity, and drawing down incredible amounts of CO2 from the atmosphere.

The only problem is that humans are butt stupid and there are waay too many of us.

You never change things by fighting the existing reality.
To change something, build a new model that makes the old model obsolete.
R. Buckminster Fuller