Overview

• Since 2003, the basin has lost about 42 million acre-feet of water storage, with groundwater depletion accounting for roughly two-thirds of that decline.
• Groundwater losses comprised about 53% of total water supply declines in the Upper Basin and 71% in the Lower Basin, exceeding storage reductions at Lake Powell and Lake Mead.
• The river’s flow has fallen about 20% over the past century, and climate models forecast up to a 30% drop by mid-century as rising temperatures shrink Rocky Mountain snowpack.
• With about 80% of basin water devoted to irrigation and a $1.4 billion agricultural sector in Arizona alone, dwindling surface supplies are driving increased groundwater pumping.
• State negotiators are racing to finalize post-2026 management guidelines, and environmental groups are urging federal limits on water waste to secure long-term supplies.