Yale Environment 360: Saguaros and palo verde trees flourish in the Sonoran Desert northwest of Phoenix along the road to Hieroglyphic Mountains Recharge, one of the Central Arizona Projects groundwater banking sites. The shallow ponds, fed at one end by a burbling fountain, may look static, but the water is percolating down through the soil at a rate of about 3 feet a day, replenishing underground aquifers.
The 38-acre Hieroglyphic site is part of a statewide water-banking effort in Arizona that has stored around...