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The Procedures Memorandum for the RGDSS Water Budget Analysis (RGDSS -Consumptive Use and <br />Water Budget Component Procedures Memorandum, April 2001, LRCWE~ describes two water budget <br />analyses -one for RGDSS Ground Water Area and one for the Rio Grande Basin Area. The RGDSS <br />Ground Water Area is similar to the San Luis Valley study area used by Emery. <br />Review of the five previous water budgets (described above) resulted in a best estimate of the order of <br />magnitude that is reasonable for each water budget component for the San Luis Valley study area. The best <br />estimate values are presented in Table 3 along with the RGDSS Ground Water Area Water Budget results. <br />Table 3 <br />Comparison of Ground Water Area Average Annual Results <br /> <br />Water Bud et Com onent Best Estimate <br />(kaf/ r) RGDSS Results <br />(kaf/ r) <br />Inflows <br />Preci itation 1,220 1,284 <br />San Juan SW Inflow' 1,200 1,249 <br />San Juan GW Inflow ~ 130 - 890 100 <br />San re de Cristo SW Inflow' 320 174 <br />San re de Cristo GW Inflow z 0 0 <br />Total Inflows 2,870 - 3,630 2,807 <br />Outflows <br />Beneficial CUs 1,470 1,018 <br />Non-Beneficial CU 4 1,000 - 1,650 1,370 <br />SW Outflow 330 305 <br />GW Outflow 70 114 <br />Total Outflows 2,870 - 3,520 2,807 <br />Chan e in Stora e <br />GW Chan e -60 0 <br />SW Chan e --- 0 <br />Total Chan e in Stora e -60 0 <br />Notes: <br />'Total San Juan and Sangre de Cristo gaged and ungaged surface water inflows. <br />~ Total San Juan ground water inflow (Sangre de Cristo considered negligible). <br />s Beneficial CU includes agriculture use from both precipitation and irrigation water, livestock use, M/I <br />use, and reservoir evaporation. <br />4Non-beneficial CU includes consumptive use by native vegetation and sublimation of winter <br />precipitation. <br />The best estimate is based on results of five previous water budget investigations of varying study periods, <br />the latest extending to 1987. The RGDSS study period is from 1950 through 1997. Differences between the <br />best estimates and RGDSS results are at least partly attributable to the differences in study periods. <br />Significant differences are summarized as follows: <br />1. The RGDSS total inflow estimate falls just below the best estimate range. The most significant <br />difference is in the Sangre de Cristo surface water inflow component. <br />2. The RGDSS total outflow estimate falls just below the best estimate range. The following identify the <br />significant differences between individual outflow components: <br />• Beneficial CU -the RGDSS estimate is lower than the best estimate. The RGDSS estimate <br />rg_task8-1_2001-08.doc 17 of 19 Apri16, 2001 <br />