Overview

• Researchers estimate about 6.3 million acre-feet of “accessible” water remains in Lakes Mead and Powell above thresholds needed for safe dam operations.
• If next year’s inflows and demands match this year, the basin could face a roughly 3.6 million acre-foot deficit by late summer 2026, further shrinking the buffer.
• Falling below 3,500 feet at Lake Powell or 1,000 feet at Lake Mead would compromise hydropower and deliveries, federal managers warn.
• Under current rules, Reclamation will reduce deliveries by 533,000 acre-feet to Arizona and Nevada and by 80,000 acre-feet to Mexico, with additional Lower Basin conservation projected, but the report deems these steps insufficient.
• The authors press the Interior Department and the Bureau of Reclamation to impose shared, near-term cutbacks across the Upper and Lower Basins as post-2026 operating rules remain under contentious negotiation.