Arizona’s cities should consider imposing unprecedented restrictions on outdoor water use if the Colorado River’s flow continues to decline as expected this year, the state’s water resources director says.

Scottsdale and Tucson already have declared themselves to be in the first stage of their respective drought plans, and are reducing government water uses. Phoenix plans to take payments from the state in lieu of some of its Colorado River deliveries next year, part of the state’s latest drought mitigation effort.