Operations and Planning

The Arizona Department of Water Resources collaborates with the Bureau of Reclamation and representatives of the seven Colorado River Basin States to better prepare for Arizona’s long-term needs and by taking an active role in water use projections, monitoring of hydrologic conditions and Colorado River operations.  The Department also utilizes models prepared by Reclamation to evaluate various scenarios related to modifications in water use, hydrology, climate, water supply and demand and other factors within the Colorado River Basin.

Annual Operating Plans – In consultation with the representatives of the Governors of the seven Colorado River Basin States, Indian tribes, Upper Colorado River Commission, appropriate Federal Agencies and others interested in Colorado River Operations, the Bureau of Reclamation  produces an Annual Operating Plan (AOP) for Colorado River Reservoirs that reports on both the past operations of the Colorado River reservoirs for the completed year as well as the projected operations and releases from these reservoirs for the coming year. Annual Operating Plans for Colorado River Reservoirs can be found here.

Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations – In 2007, the Secretary of the Interior signed the Record of Decision for the “Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Lake Mead.” These Interim Guidelines are intended to be applied each year during the Interim Period (2008–2026) in implementing the Long-Range Operating Criteria (LROC) for the Colorado River reservoirs. 

24-Month Study -  The monthly 24-Month Study reports present hydrologic descriptions and projected operations for the Colorado River system reservoirs for the next two years. Reclamation uses this model to provide current status and projected operation of the system on a monthly basis.  The 24-Month Study model is updated at the beginning of each month upon receipt of the monthly inflow forecast from Colorado Basin River Forecast Center (CBRFC). Under the 2007 Interim Guidelines, the August study model is the basis for the decision for Lake Powell and Lake Mead annual operations for the coming year.  The April study model is used to make potential adjustments to Lake Powell’s annual operation at higher reservoir levels. 24-Month Study Reports can be accessed here.

Colorado River Basin Supply and Demand Study – The Colorado River Basin Supply and Demand Study characterized current and future water supply and demand imbalances in the Colorado River Basin and assessed the risks to Basin Resources. Resources include water allocations and deliveries consistent with the apportionments under the Law of the River, hydroelectric power generation, recreation, fish and wildlife, and their habitats, water quality (including salinity) and flow, as well as water-dependent ecological systems and flood control.  A full report on the Colorado River Supply and Demand Study can be found here.

Colorado River Simulation System (CRSS) – CRSS is the official long-term basin-wide planning model for the Upper and Lower Colorado Regions to simulate future Colorado River conditions.  Specifically, the model projects future river and reservoir conditions over a period of decades into the future.  ADWR can modify model inputs to simulate possible water planning or management strategies, such as conserving water in Lake Mead, to assess impacts to the system from such strategies. For more information on CRSS click here.