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SOUTH PLATTE BASIN Basinwide Conditions Assessment The SWSI value for the month was 1.3. Reservoir storage in Dillon, Horsetooth, Eleven Mile, Cheesman, Jackson, and Barr Lake, the major component in this basin in computing the SWSI value, was 1050/0 of normal as of the end of June. Cumulative storage in the major plains reservoirs: Julesberg, North Sterling, and Prewitt, is at 920/0 of capacity. Cumulative storage in the major upper-basin reservoirs: Cheesman, Eleven Mile, Spinney, and Antero is at 1020/0 of capacity. Flow at the gaging station South Platte River near Kersey was 1638 cfs, as compared to the long- term average of 2321 cfs. Flow at the Colorado/Nebraska state line averaged 572 cfs. Outlook The flow in the South Platte dropped dramatically in June as snow melt runoff ended, weather conditions on the plains became drier, irrigation demand increased. With these changes, demand finally outstripped supply and there was a direct flow call for irrigation on the river for the first time on June 12, 2007 after seven weeks of free river. Seven weeks is the longest period of free river that has existed on the South Platte since 2001. Administrative/Manaqement Concerns By the end of June, some irrigation users along the mainstem and tributaries had also begun using their reservoir supplies though reservoirs remained near full. Municipal users also generally still had full reservoir supplies. With these conditions, it is fairly certain that those who depend on senior surface supplies and reservoirs will have an adequate water supply this year. The one exception is the Poudre basin which did not have as good a snow pack and supplies continue to be less than average. Public Use Impacts Of note, the governor initiated a Task Force to look at possible solutions for well users in the South Platte basin who own junior water rights without adversely impacting senior water right holders. The first task force meeting was held June 29th in Greeley. To date, Division 1 has issued orders to cease use concerning approximately 2400 wells in the South Platte basin. In addition, Division 1 is still investigating approximately 1600 wells generally located further from the river. In contrast, over 5000 wells are operating in accordance with decreed augmentation plans or Substitute Water Supply Plans. Additional information concerning subsequent meetings of the Task Force may be found at http://www.ag.state.co.us/SouthPlatteTF.html. Jul-07 8JUTH PLATTE BASIN SV\JE!). HISTORY I- W S 1.0 W :J <( > 0.0 CiS ~ >- -1.0 ~ -4.0 Jan-98 Jan-99 Jan-OO Jan-01 Jan-02 Jan-03 Jan-04 Jan-OS Jan-OO Jan-07 rvlCNTH / YEAR SOUTH PLA TIE RIVER NR. KERSEY, FLOW BY WATER YEAR 3,000,000 ill 2,500,000 Q) LL ill ~ 2,000,000 s- o ---l LL 1,500,000 w > i= ~ 1,000,000 ~ :J U 500,000 o Oct Nov Dee Jan Feb March April May June July Aug Sept -----8-- WET (1983) --+- DRY (1964) ---fr- AVG --* 2007 REPRESENTATIVE RESERVOI RS 300,000 250,000 Q3 ~ 200,000 ~ co Q)- g 150,000 (; U5 Q) :c m 100,000 :J 50,000 Dillon Horsetooth Eleven Mile Cheesman Jackson Barr Lake II Avg.06/30 Contents II 06/30/07 Contents 3