AN ON-GOING DROUGHT IN THE COLORADO RIVER BASIN (CRB) HAS REDUCED LEVELS IN LAKE MEAD TO THE EXTENT OF POTENTIALLY TRIGGERING A WATER SHORTAGE. IN THIS CONTEXT A SHORTAGE REFERS TO REDUCTIONS IN ANNUAL WATER ALLOCATIONS THAT WOULD IMPACT AGRICULTURAL MUNICIPAL AND INDUSTRIAL SECTORS. THE EXTENT TO WHICH CRB CONSTITUENTS CAN AVOID A DROUGHT SHORTAGE DEPENDS ON MANAGEMENT DECISIONS MADE IN LIGHT OF LONG-RANGE WATER SUPPLY PROJECTIONS. IN ARIZONA THE CENTRAL ARIZONA PROJECT (CAP) IS THE WATER CONSERVATION DISTRICT IN CHARGE OF AN INFRASTRUCTURE SYSTEM THAT DELIVERS COLORADO RIVER WATER TO MULTIPLE USERS IN THE STATE. CURRENTLY WATER SUPPLY DECISION MAKING AT CAP RELIES ON A 24-MONTH FORECAST FROM THE U.S. BUREAU OF RECLAMATION ISSUED ON A MONTHLY BASIS. AS A RESULT CAP HAS NOT YET DEVELOPED AN IN-HOUSE CAPACITY FOR LONG-RANGE (2 TO 25 YEAR) HYDROLOGIC PROJECTIONS THAT CAN SERVE AS INPUT TO SCENARIO PLANNING AND DECISION-MAKING ACTIVITIES. EVALUATING ALTERNATIVE WATER MANAGEMENT STRATEGIES RELIES ON THE CAPACITY TO TRANSLATE CHANGES IN FUTURE CLIMATE AND LAND COVER CONDITIONS INTO WATER SUPPLY PROJECTIONS AT KEY LOCATIONS ALONG THE COLORADO RIVER. IN THIS PROPOSAL ARIZONA STATE UNIVERSITY AND THE COLORADO RIVER PROGRAMS DIVISION AT CAP HAVE PARTNERED TO TRANSITION AN OPERATIONAL HYDROLOGIC MODEL TO ASSESS THE CLIMATE AND LAND USE CHANGE RISKS TO LONG-RANGE WATER SUPPLY SECURITY IN THE CRB.