DWR_4151804 - Laserfiche WebLink

• COLORADO WATER SUPPLY CONDITIONS UPDATE PROM THE OFFICE OF THE STAR ENGINEER; DIVISION OP WATM RESOURCES November, 1990 ROOM 613,1313 SHERMAN Sr..DWV$R,CO 30203; (303)466 33I1 Statewide precipitation was above normal for the month of October. Precipitation averaged 141% of normal with a high of 164% of normal in the Yampa/White basin and a low of 117% of normal in the Arkansas basin. As is common in Colorado, precipitation varied considerably. Streamflow,however,was below normal for the month of October in the Gunnison and Yampa/White basins. Although reservoir storage has been drawn down considerably in the last 12 months, statewide it still remains normal to above normal when compared to historic reservoir storage levels. Storage levels are below normal in the Rio Grande and Colorado basins. Relative storage remains highest in the Arkansas basin. The consumption of reservoir carry- • over storage this year will impact conditions next year if the 1991 runoff is below normal and as a result storage cannot be replaced. The greatest impacts would be on recreational uses of water. Cumulative annual streamflow at key index gaging stations approached twenty year lows in the Gunnison and Yampa/White basins. Even with significantly above normal precipitation for the month,streamfiow remained low in these basins due to low soil moisture levels. Soil moisture deficiency remains at moderate to high levels in the west-central and northwest sectors of the state but has improved over the last three months. The Surface Water Supply Index (SWSI) developed by this office is used as an indicator of water supply conditions in the state. It is based on reservoir storage, streamfiow and precipitation for the summer period (May 1 through December 1). Weight factors are applied to each of the measured hydrologic factors in computing the SWSI values. During the summer period, streamflow is the primary component in each basin except the South Platte where reservoir storage is the primary component The following SWSI values were computed for each of the seven basins on November 1, 1990. November 1 Change from Basin . SWSI Value October 1, 1990 South Platte • +1.8 -0.3 Arkansas +2.6 +2.7 Rio Grande +2.8 +2.8 • Gunnison -1.3 +0.6 Colorado -0.6 0.0 Yampa/White -1.8 +0.9 San Juan/Dolores +2.7 +2.4 SCALE -4 -3 -2 -1 0 +1 +2 +3 +4 Severe Moderate Near Normal Above Normal Abundant Drought Drought Supply Supply Supply 1