Ensuring Long-Term Viability of the Colorado River System Through Early, Proportional Cuts to Water Deliveries During Low Water Years

The Upper Basin of the Colorado River, under current agreements, must prioritize releases between 7.48 and 9.0 million acre feet (maf) of water to the Lower Basin of the Colorado River per year. This delivery is controlled by outflows from Lake Powell which until recently could not be less than 8.23 maf. This release represents the downstream allocations for Mexico, regional Native American tribes, and the Lower Basin states. This report presents a management alternative that allows for proportional releases from Lake Powell based on inflows. This report recognizes that any alteration to the existing schedule of deliveries from Lake Powell downstream is politically fraught. However, there is a pressing need to ensure that water and electrical demands are met, even if in lesser quantities, during the projected driest years of the coming decades. The results of the new rule show that Lake Powell is kept above power pool elevation longer than without the rule in place.