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I III( COLORADO WATER SUPPLY CONDITIONS UPDATE FROM THE OFFICE OF THE STATE ENGINEER: COLORADO DIVISION OF WATER RESOURCES ROOM 818,1313 SHERMAN ST., DENVER. CO 80203 303-866-3581; www.water.state.co.us April 2006 The Surface Water Supply Index (SWSI) developed by this office and the U.S.DA Natural Resources Conservation Service is used as an indicator of mountain-based water supply conditions in the major river basins of the state. It is based on snowpack. reservoir storage, and precipitation for the winter period (November through March). During the winter period. snowpack is the primary component in all basins except the South Platte Basin where reservoir storage is given the most weight. The following SWSI values were computed for each of the seven major basins for April 1, 2006. and reflect the conditions during the month of March. The SWSI values for this month show a near normal or higher value for all of Colorado, except the San Juan/Dolores and Rio Grande Basins in the southwest. The southwest basins did, however. show improvement in the past month, which was caused by March storms that dropped significant amounts of snow to the part of the state that needed it most. The current SWSI values range from a high of +1.6 in the Colorado Basin to a low of -1.5 in the Rio Grande Basin The statewide snowpack averages range from highs of 111 % of normal in the YampalWhite Basin and 110% in the Colorado Basin to lows of 64% in the Rio Grande Basin and 68% in the San Juan/Dolores Basin. April 1 , 2006 Change From Change From Basin SWSI Value Previous Month Previous Year South Platte +0.5 -0.8 +0.8 Arkansas +0.5 -1.1 +1.8 Rio Grande -1.5 +1.3 -4.7 Gunnison +0.7 +0.6 -1.9 Colorado +1.6 -0.5 +2.0 YampalWhite +0.8 - 0.1 +3.0 San Juan/Dolores -1.3 +1.0 -3.6 Scale -4 -3 -2 -1 0 1 2 3 4 Severe Moderate Near Normal Above Normal Abundant Drought Drought Supply Supply Supply