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Model. Recommendations regarding Decreed alternate point wells, designated basin wells, and <br />Coffin wells are also included in this memorandum. <br />The following comments and concerns are based on information reviewed and discussions with <br />augmentation plan personnel, Division 1 personnel, and DWR and CWCB personnel: <br />• The well ID-augmentation plan ID-recharge site ID associations in HydroBase are constantly <br />updated. These associations represent a snap shot in time and do not represent a time series. <br />• Correspondence with the Division 1 office indicates a change to the recording of <br />augmentation plans has recently been implemented. Specifically, a new Water Data Bank <br />Code -Group (G), has been added to the currently used S: F: U: T: coding to include the <br />augmentation plan ID in the Group code. <br />• Augmentation plan water rights cannot currently be extracted using DMIs via a Structure ID <br />water rights query but can be extracted via a Transaction List water rights query based on <br />Plan ID and Use =RCH or Use =AUG. <br />• Many structures are decreed for RCH and/or AUG in addition to IRR and possibly a number <br />of other uses. <br />• Assigning recharge and augmentation water rights directly to the plan ID, along with carrier <br />structures for the rights, would be helpful for plan ID water right queries in HydroBase. <br />• Although the water rights data in HydroBase are constantly updated, the water rights query <br />used in the approach for this model did not produce augmentation supplies for all of the 25 <br />major plans presented in Table 3. As the data available in HydroBase expands and is quality <br />controlled, the data-centered StateMod representation for the SPDSS model should be able to <br />integrate the new data easily. <br />• The approximately 100 remaining well augmentation plans included in Table 3 are relatively <br />small. In addition, the wells in these smaller plans and the acreage associated with the wells <br />in the smaller plans, may be associated with one of the 25 major well augmentation plans. <br />The recommendation herein is that the hydrologic effects from operating the remaining wells <br />should be represented, but augmentation of the well depletions in the smaller augmentation <br />plans should not be explicitly represented. <br />• Well users in the South Platte River basin need to provide projections of summer well <br />pumping, lagged depletions, and replacements to the Division office each April. This practice <br />generally started after the recent drought and development of multiple-year projections each <br />year has been added as a term and condition to recent Water Court decrees for well <br />augmentation plans. One result of this practice has been that ditch plans and non-ditch plans <br />have needed to set use quotas for member wells each spring, which often limit well pumping <br />the following summer. Recent quotas reported for augmentation plans have widely varied <br />among plans. One example is the Central Ground Water Management Subdistrict (GMS) <br />plan, which must produce six-year projections of depletions and replacements for each year <br />of pumping. The GMS decree requires that dry-year yields for certain ditch shares and zero <br />acre-feet for recharge diversions be used in the projections, which resulted in a 50 percent <br />quota for water year 2006 and a 30 percent quota for 2007. Incorporation of plan quotas <br />would likely provide better agreement between actual well pumping and simulated pumping <br />to meet the full crop irrigation water requirement. <br />15 of 16 <br />