DWR_4151842 - Laserfiche WebLink

it • COLORADO t WATER SUPPLY CONDITIONS UPDATE FROM THE OFFICE OF THE STATE ENGINEER; COLORADO DIVISION OF WATER RESOURCES September 1996 ROOM 818,1313 SHERMAN ST.,DENVER,CO 80203; (303)-866-3581 The southern mountains continue to experience the driest conditions in the state. This is reflected the Animas/La Plata and Rio Grande basins having the lowest SWSI values. While the Arkansas basin SWSI is not as low as the other two southern tier basins, the tributaries on the south side of the Arkansas River are also experiencing extremely low flows. The South Platte and Colorado were the only basins with stream flow percentiles above 50%. The precipitation stations which go into computing the SWSI indicate that all basins received well below normal precipitation during August. The highest precipitation percentile used in computing this month's SWSI was 35%, which occurred in the Rio Grande basin. The Surface Water Supply Index (SWSI) developed by this office and the U.S.D.A. 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 stream flow, reservoir storage, and precipitation for the summer period (May through October). During the summer period stream flow 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 September 1, 1996 and reflect conditions during the month of August. Sept. 1, 1996 Change From Change From Basin SWSI Value Previous Month Previous Year South Platte +2.8 +0.2 -0.3 Arkansas +0.5 -1.3 -3.3 Rio Grande -2.2 +0.3 -4.9 Gunnison -0.7 -0.3 -4.3 Colorado -0.1 +0.8 -3.9 Yampa/White -1.4 -2.4 -3.0 Animas/La Plata -3.5 -0.9 -6.8 SCALE -4 -3 -2 -1 0 +1 +2 +3 +4 Severe Moderate Near Normal Above Normal Abundant Drought Drought Supply Supply Supply 1