Cumulative Effect Report on Plan for Future Depletions

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are the same as Scenario A and are those stated in the CPFD, Paragraph C. The results of this analysis show that May and June are still months of net depletions (2,713 acre-feet). Colorado made similar estimates for Scenario B in 2008 as presented in Figure 2-2008, which also reflects an adjustment for reduced development of native water supplies, an increased use of reusable water supplies, and an additional population increase of 58,843 persons over the 2007 population. The results of this analysis show again that May and June are months of net depletions (2,972 acre-feet). Colorado's Miti2ation Measures Colarado's mitigation commitment in the PRRIP is to undertake re-regulation projects within Colorado to shift water flows from periods of net accretion to periods of net depletion. The only months with net depletions are the months May and June. Colorado has begun to re-time excess flows in these months through managed groundwater recharge. Colorado began pumping two recharge wells next to the river in January 2007 at the Colorado Division of Wildlife's Tamarack Ranch recharge project and Colorado began pumping six more Tamarack wells in the first week in March 2007. Colorado will continue to pump in Apri12007 until water is no longer available under the South Platte compact and/or Colorado water law. In addition, Colorado has committed to additional pumping of recharge wells into the Peterson Ditch for this spring of 2007, depending upon water availability, pursuant to Colorado's South Platte River water right demands and/or compact requirements. Colorado is also in the process of developing leases with the owners of private recharge projects for the lease of their excess recharge accretions in May and June that result from diversion of the net monthly accretions associated with the CPFD. A combination of these re- timing activities will be utilized to accomplish Colorado's obligations under its Plan for Future Depletions. Colorado will provide the results from their initial operations in the first annual information report in January 2008. Appendix A Adiustment for reduced native South Platte flow development Throughout the Platte Basin, there has been an extended drought beginning in 2000. The use of native South Platte flows with a priority date junior to July 1, 1997 (start date for new water related activities) has been minimal during this drought. Colorado requests that the Governance Committee consider a modification to the percent water supply from native South Platte flow development used for new water related activities. A good indication and basis for this modification is the frequency of river calls on the South Platte River. Figure 3 lists the monthly percents far April through July that a July 1, 1997 priority date would be out-of-priority for the period 1998 through 2006. The April through July period is the spring runoff period from snowmelt and is the time when South Platte flow development would take place under junior water rights as assumed in the CPFD (i.e., South Platte flow development assumed to occur at 5% in April, 40% in May, 50% in June, and 5% in July). The call records used in this analysis are from the records of the Colorado State Engineer's Office. The initially assumed percent water supply source mix by region of the CPFD, Paragraph B, was for the period 1998 through 2002. As listed in Figure 2, the weighted percent of time for a July 1, 1997 water right to be in-priority is 53% for 1998-2002 versus 33% for 1998-2006. 4