When the Colorado River reaches flood stage, it becomes a losing stream and water begins to flow from the river to the groundwater system. In 1983-1984, large volumes of water were released from reservoirs upstream resulting in an increased river stage of 17 feet at the Yuma gage. The Algodones Fault trends northwest to southeast across the basin south of Yuma. The fault provides a barrier to groundwater movement which is evident by significant differences in water-level altitudes on each side of the fault. Some of the groundwater was pumped to control rising water levels caused by irrigation and associated practices.
Water quality varies with depth and location.
Volatile organic compound contamination has been reported at the Yuma Marine Corps Air Station.