More than 3,000 square miles of Arizona has subsided, due to groundwater pumping, including an area of 100 square miles in Pinal County between Phoenix and Tucson that sank 7 feet between 1952 and 1977, according to testimony by Arizona water chief Herb Guenther in testimony last week.
Herb raised concerns that the 100 year assured supplies of water are based on allowing groundwater mining down to 1,000 feet, but what happens then? How do you replace the water and how do you deal with the resulting subsidence?
[right, active subsidence areas in Arizona, based on ADWR InSAR]