WSP12524 - Laserfiche WebLink

Home Browse Search

OOd2D7 Southwest Colorado's Snowpack Improves but, it's Still Below Average A powerful, mid-March storm added to the southwest Colorado's snowpack and improved the water situation, but the region is still playing catch-up. According to information from the March 1 "Colorado Basin Outlook Report," published by the USDA's Natural Resources Conservation Service, the San Miguel, Dolores, Animas and San Juan River basins "finally received some much-needed, above-average snowfalls during February." "Overall, the snowpack accumulation went up 22% of average from last month Oanuary) and is now 63% of average. All of the watersheds managed to receive additional snow accumulation during February, but the Animas and the Dolores watersheds were by far the biggest winners with some of the largest increases in snowpack percent of average in the state." Even with that moisture, the lower elevations and valleys received only 84% of average precipitation during February, according to the report, and the water year total (as of March 1) was only 43% of average. Good news comes in the form of southwest Colorado's reservoir storage, which is 116% of average for this time of year and 16% more storage than last year at this time. The forecasted streamflows for this runoff season remain below average, and the improved snowpack conditions have allowed many of the forecasts to improve as well. The streamflows are highly variable and range from 50% on the Rio Blanco at Blanco Diversion, to 82% of average on the San Miguel River near Placerville. Caution is still the watchword. "Even with the additional snowfall, most of the state can continue to expect a below average runoff season in 2000." The statewide snowpack is 80% of average as of March with the northern half of the state at near-or above- normal snowpacks and decreasing amounts the farther south one travels from 1-70. Precipitation in the lower elevations, though improving, still lags. "Water year totals for the first five months of the water year remain below average in all basins and are only 69% of average for the state." Reservoir storage is "one of the brightest highlights of the 2000 water year," according to the report, with storage statewide at 142% of average. "This volume amounts to slightly more than 1.3 million acre-feet above the average mark for March 1, and is 10% more than last year's storage." For streamflows statewide, the repon notes an improved prospect for runoff, but foresees "below average volumes for most of the state's rivers." , r Surface Water Supply I Index for Colorado LEGEND Major River ""'--/"" Basin Boundary ."..-. SWSI Value [KE] SCALE +4 Abundant Supply +2 Near Normal .2 Moderate Drought -3 Severe Drought -4 Extreme Drought March 1 J 2000 The Surface Water Supply Index (SWSI) is a weighted value derived for each major basin which generally expresses the potential availability of the forthcoming season's water supply. The components used in computing the index are reservoir storage, snowpack water equivalent and precipitation. The SWSI number for each basin ranges from a -4.0 (prospective water supplies extremely poor) to a +4.0 (prospective water supplies plentiful). The SWSI number is only a general indicator of surface water supply condition. Further data analysis may be required in specific situations to more fully understand the impacts of abnormally dry or wet conditions suggested by the SWSI. Development of the SWSI has been a cooperative effort between the Colorado State Engineer's Office and the Natural Resources Conservation Service. , 3