We "use" water so poorly for agriculture and cities. I lived in Imperial Valley California. They have an open canal through a very dry desert for 100 miles. The canal is made of porous concrete that leaks along the way. It is then used in the farms to produce what I was told is the majority of America's lettuces and vegetables.

They LOVE farming out here since there is virtually no rain or weather events to complicate things. They have everything down to a science and a tight schedule that rarely if ever changes. We use up 90%+ of the Colorado River for this one purpose. We then ship these all across the nation using more resources. Seems a bit wasteful.

So how much water to produce a head of lettuce?