Colorado Water Dec 2003 - Laserfiche WebLink

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WA TER SUPPL Y All basins reported lower than normal pre- cipitation during October, dropping the SWSI value compared to last month. The dry condi- tions are maintaining lower than normal stream flows in most all drainages, with a few record low flows reported in the Yampa/White basin. However, conditions are generally not as bad as they were in 2002. The end of October typically represents the end of the irrigation season with diversions direct to irrigation ceasing. Many irrigation reservoirs, especially off - channel reservoirs in the South Platte basin, begin to store water as the senior direct -flow irrigation rightss stop calling. Diversions to recharge ground water also begin in the South Platte basin. The Rio Grande basin experienced a bit longer demand for direct -flow irrigation water due to the dry conditions. All water users are hoping for a good snowpack accumulation over the winter, which will be the key to adequate water supplies in 2004. The Surface Water Supply Index (SWSI) developed by the State Engineer's Office and the USDA 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 streamflow, reservoir storage, and precipitation for the summer period (May through October). During the summer period, streamflow 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, 2003, and reflect the conditions during the month of October. Basin 11 11 103 SWSI Value Change From Previous Month Change From Previous Year South Platte -0.3 -1.3 +1.9 Arkansas -1.8 -1.0 +0.7 Rio Grande -2.0 -2.8 +0.9 Gunnison -3.4 -1.0 -0.6 Colorado +0.1 -0.9 +3.6 Yampa/White -3.2 -1.9 0.0 San Juan/Dolores -1.7 -4.0 -0.5 Severe Moderate Near Normal Above Normal Abundant Drought Drought Supply Supply Supply WATER NEWS DIGEST wkYti , '�--�; by Marian Flanagan t. CLOUD SEEDING CSU researches cloud- seeding Colorado State University researchers will try to determine once and for all this winter if Denver Water's cloud- seeding efforts effectively enhance snowfall, boosting snowpack and reservoir levels. They will compare predicted and actual snowfall accumulations in areas targeted by seeding and in control areas where there is no seeding. The researchers will use computer - generated weather models to predict anticipated snowfall from a given storm, and then will factor in cloud- seeding data and snowfall tallies to try to detect whether the seeding is working. "This is the first time this type of study will be done on a real -time basis," said Western Weather Consultants manager Larry Hjermstad. Two studies completed last summer showed conflicting results. A statistical analysis of snowfall data indicated the seeding was effective, boosting accumulations by about 14 percent. But a second study did not find significant traces of silver iodide in the intended target areas, indicating "a failure to routinely seed the intended cloud regions." Deriver Post / October 20, 2003 34 - SCU -4 -3 -2 1 -1 0 1 +1 1 +2 +3 +4 Severe Moderate Near Normal Above Normal Abundant Drought Drought Supply Supply Supply WATER NEWS DIGEST wkYti , '�--�; by Marian Flanagan t. CLOUD SEEDING CSU researches cloud- seeding Colorado State University researchers will try to determine once and for all this winter if Denver Water's cloud- seeding efforts effectively enhance snowfall, boosting snowpack and reservoir levels. They will compare predicted and actual snowfall accumulations in areas targeted by seeding and in control areas where there is no seeding. The researchers will use computer - generated weather models to predict anticipated snowfall from a given storm, and then will factor in cloud- seeding data and snowfall tallies to try to detect whether the seeding is working. "This is the first time this type of study will be done on a real -time basis," said Western Weather Consultants manager Larry Hjermstad. Two studies completed last summer showed conflicting results. A statistical analysis of snowfall data indicated the seeding was effective, boosting accumulations by about 14 percent. But a second study did not find significant traces of silver iodide in the intended target areas, indicating "a failure to routinely seed the intended cloud regions." Deriver Post / October 20, 2003 34 -