SWSIReportSept2004 - Laserfiche WebLink

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SOUTH PLATTE BASIN .~ Basinwide Conditions Assessment The SWSI value of 1.1 indicates that for August the basin water supplies were near normal. Reservoir storage, the major component in this basin in computing the SWSI value, was 103% of normal as of the end of August. Cumulative storage in the major plains reservoirs: Julesberg, North Sterling, and Prewitt, is at 18% of capacity. Cumulative storage in the major upper-basin reservoirs: Cheesman, Eleven Mile, Spinney, and Antero is at 78% of capacity. Flow at the gaging station South Platte River near Kersey was 622 cfs, as compared to the long-term average of 505 cis. Flow at the Colorado/Nebraska state line averaged 38 cfs. Conditions in August were generally wet. One major rainstorm in Denver the latter part of August provided significant supplies along the river. The increased supply and reduced demand associated with the rain kept the call from becoming extremely senior, as occurred in 2002 and 2003. For reference, the senior call along the mainstem above Kersey in August of 2004 was often junior to 1872, allowing all major irrigation rights above Kersey except Burlington ditch an adequate direct flow supply. This is in conlrastto 2002 when the call was generally 1865, preventing most ditches from having an adequate supply. Users who depended on their direct flow rights have had an adequate supply of water. Despite the calls not being extremely senior, agricultural users who are dependent on reservoir supplies are in a very difficult situation as irrigation reservoirs have been severely depleted after many did not fill in the spring. Major irrigation suppliers who have had to limit their deliveries include North Sterling, Prewitt, Riverside, Farmers Reservoir and Irrigation Company and Empire. No additional releases are being made from Prewitt or Empire by the last week of August. AdministrativelManaoement Concerns Rainstorms have caused rapidly changing surface flow conditions requiring extensive efforts by administrators to make sure that the gages on the sand channels of the South Platte are accurate and that they administer the rapidly changing flows to the correct water users. There already have been 170 changes in mainstem call this water year through August 20, compared to an average of 60 call changes through the whole irrigation season over the previous twenty years. Public Use Impacts This year, many irrigators chose to switch to crops requiring less water, including beans, small grains, wheat, or barley. In addition, there has been dry up of acreage associated with weli augmentation requirements. Most municipalities remain in much better shape this year than 2002 due to the wetter than usual summer conditions, conservation efforts and leasing of additional supplies. Their storage supplies continue to exceed those that were available last summer. Sep-04 ""''''''''' ~ , ~ i' ~' < . ~.-.e~.-..mJrolllJlr>l1l.-...cnJln(l2J1nQ3~ ."..,,- SClJTH PlATTE RI'V'ffi fIR I<ERSEY, FL.DN BY WATER YEAR '000.000 "".000 - / / / ~ ~ - 2.5JO,0CXl ~ ~ < 2.000,(00 ~ ~ ~ 1,5JO,0Xl > ~ ~ 1.000.000 ~ ~ u o W;f\t:.vOocJcr1FebM:rdlP9UtvtJy..llneJJykgSeIX -o-WET(19B3) __CRV(1964) ~AVG ......"'" REPRESENTATIVE RESERVOIRS '''''''' '"''''' j ~ 150.CIXI . f ~100.<ro ~ S '""" o DJro ~ Ell:MIn Mile O1eesman Jad\sa1 ""'.... .Avg.8131 CootenlS D&'31I04Contents 3