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f,. <br /> COLORADO <br /> } WATER SUPPLY CONDITIONS UPDATE <br /> FROM THE OFFICE OF THE STATE ENGINEER; COLORADO DIVISION OF WATER RESOURCES December, 1994 <br /> LOOM 818,1313 SHERMAN ST.,DENVER,CO 80203; (303)-866r3581 <br /> Because stream flows typically decline to base flow amounts supplied primarily by ground water discharges during <br /> the winter, and because the winter's snowpack begins to accumulate during November, the major factor used to compute <br /> the Surface Water Supply Index is changed from stream flow (summer factor) to snowpack (winter factor) this month. The <br /> Natural Resources Conservation Service (formerly the Soil Conservation Service) reports December 1 snowpack as 121%of <br /> average statewide, based on SNOTEL data. The switch from stream flow to snowpack factors and the snow received in <br /> November resulted in increased SWSI values for many of the basins. <br /> The Natural Resources Conservation Service reports that the southern mountains received the largest amounts of <br /> snow. While snowpack is above average in these southern areas, it is still to early to tell what next springs runoff will be <br /> like. The winter of 1993/94 started with good a snowpack which deteriorated to below normal amounts by spring. ..The <br /> National Weather Service's 30 and 90 day outlooks as of December 1 both show expectations for above normal precipitation:-, <br /> over the entire state. <br /> The Surface Water Supply Index (SWSI) developed by this office and the U.S.D.A. Natural Resources Conservation <br /> Service is used as an indicator of mountain based water supply conditions in the major river basins of the state. It is based <br /> on snowpack,reservoir storage,and precipitation for the winter period (November through April). During the winter period <br /> snowpack is the primary component in all basins except the South Platte basin where reservoir storage is given the most <br /> weight. The following SWSI values were computed for each of the seven basins on December 1, 1994 and reflect conditions <br /> during the month of November. <br /> December 1, 1994 Change From Change From <br /> Basin SWSI Value Previous Month Previous Year <br /> South Platte 0.0 -1.9 -2.6 <br /> Arkansas +2.1 +0.1 0.0 <br /> Rio Grande +3.1 +1.5 +3.3 <br /> Gunnison +2.3 +1.5 +1.3 <br /> Colorado +0.9 +2.3 -1.5 <br /> Yampa/White +0.8 +3.0 -1.1 <br /> San Juan/Dolores +3.3 +1.9 +3.2 <br /> • <br /> SCALE <br /> -4 -3 -2 -1 0 +1 +2 +3 +4 <br /> Severe Moderate Near Normal Above Normal Abundant <br /> Drought Drought Supply Supply Supply <br /> 1 <br />