Reclamation’s Upper and Lower Colorado Basin Regions generate a set of standard projections of Colorado River Basin system conditions at regular intervals to determine reservoir operations and assist with planning. Each set of projections serves a specific purpose and focuses on either annual or mid-term (1- to 5-year) time horizons. Standard projections currently extend through 2026, the year the 2007 Interim Guidelines, the Colorado River Basin Drought Contingency Plans, and Minute 323 to the 1944 Treaty with Mexico expire. Long-term outlooks (beyond 5 years) are generated for specific study purposes but are not included in Reclamation’s regularly scheduled suite of products.

The models used to generate projections are implemented in RiverWare^TM, a commercial river modeling platform developed by the Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) at the University of Colorado Boulder. The models are maintained and continually updated by Reclamation’s Upper and Lower Colorado Basin Regions.

Because it is impossible to predict exactly how future climate, hydrology, and water demands will unfold, all projections are subject to some amount of uncertainty, and this uncertainty increases as projections look further out. Modeling assumptions about the future and the incorporation of uncertainty vary by projection purpose and length. Information about Reclamation’s modeling approaches and the data used for each set of projections is accessible from the current projections sites or on the General Modeling Info page. We recommend reading modeling approach material along with this discussion about uncertainty for context when viewing the projections.