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estimated total inflows (surface and ground water) using results of a detailed water budget for the San Juan Mountains. The results by Emery were used by HRS Consultants, and Emery's approach was adopted by Schroeder but for a different study period. Huntley relied on an average of available streamflow records without adjustment for a study period. San Juan Ground water: Huntley and Hearne estimated ground water inflows from the San Juan Mountains as the residual of water budgets conducted on the San Juan basin. HRS estimated ground water inflows as a result of their ground water modeling study. Schroeder estimated San Juan ground water inflow using Darcy's Law. Ground water inflows were not estimated by Emery. The range is 0 kaf/yr (Emery) to about 890 kaf/yr (Hearne) Sangre de Cristo Surface Water: Surface water inflows from the Sangre de Cristo Mountains were estimated based on relationships developed using available gaged stream flow records by all investigators. Emery relied upon local stream gages in Rio Grande basin of Colorado to develop an altitude-runoff relationship, which HRS and Schroeder also adopted. Huntley relied upon one long- term stream gage record in the Sangre de Cristo Mountains to extend intermittent stream flow records of 10 other basins. Hearne estimated inflows using a regression model based upon basin area and winter precipitation. Fifteen out of 16 stream gages used to develop the relationship by Hearne, however, were in New Mexico. Sangre de Cristo Ground Water: Huntley conducted a water budget on the Sangre de Cristo Mountains to estimate ground water inflows. Emery, Hearne and Schroeder estimated that gaged flows represented the total yield of the Sangre de Cristo mountains, given the geology of the Sangre de Cristo mountains and location of stream gages above the San Luis Valley alluvium. HRS Consultants estimated the ground water inflow as part of its ground water modeling efforts. HRS's estimate is also equal to the difference of Hearne's estimated total inflow (which Hearne estimates is all surface water) and Emery's estimated surface water inflows. The different approaches to estimating inflow from the Sangre de Cristo Mountains lead to varying estimates of total inflows. This can best be ascertained by comparing inflow estimates to the Closed Basin; Emery (158 kaf/yr), Huntley (254 kaf/yr), and Hearne (187 kaf/yr). Based on the average of Emery and Schroeder, total inflow to San Luis Valley is on the order of 315 kaf/yr. Outflows -Outflows to the water budgets consists of up to four components; beneficial consumptive use, non-beneficial consumptive use, surface outflow and ground water outflow. Beneficial Consumptive Use: -Beneficial consumptive uses include crop consumptive use, municipal use, commercial use, and industrial use. Municipal, commercial and industrial uses were ignored in all water budgets except Schroeder's, which considered 4,000 of/yr of consumption. Emery (1973) only reports amounts of consumptive use (beneficial and non-beneficial) and does not discuss the basis for the estimates. Crop consumptive use was estimated by Huntley, HRS, Hearne and Dewey, and Schroeder by relying upon estimates of irrigated lands, crop types, and the Blaney-Griddle method (original, and modified with calibrated crop coefficients) to estimate potential crop consumptive use. In Schroeder's analysis actual consumptive use is calculated by comparing water supplies to potential consumptive use. However, it is not clear in the other studies if water supplies were compared to potential consumptive use for an estimated actual consumption, or if the potential consumptive use was used as actual consumption. Non-beneficial Consumptive Use: Non-beneficial consumptive use includes evapotranspiration (Et) of non-irrigated lands and sublimation of winter precipitation. Non-beneficial consumptive use was rg_task8-1_2001-08.doc 14 of 19 Apri16, 2001