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.---0_- Cal ibration of the Badger Creek Valley Model Cal ibration of the Badger Creek valley model was complicated by three, 'factors: (1) Data with which to reconstruct historic development, particu-; larly water-level data, are less abundant than for Beaver Creek valley; I (2) much of the modeled area is part of the South Platte River alluvium with, \-Iater levels controlled by the regional system; and (3) much of the modeled' area is irrigated by unknown quantities of surface water. Because of these factors, the model was not cal ibrated to the detail achieved for the Beaver Creek valley model. The hydraulic-conductivity value used was a uniform value of 90 ft/d (the same as that used in most of the areas for Beaver Creek valley). ! A technique was used to compute the flux at each node that would main- tain hydraulic heads at the level contoured using the 1978 data. In total,: these fluxes provide useful information relative to boundary fluxes, net withdrawal, and recharge. The value at any individual node is not, however,' a very reliable estimate of the site-specific recharge or discharge. This is, because: (1) The technique cannot smooth out the disjunctive water table' created when using 10-ft contour intervals; (2) an average water level (at' the center of a nodal area) needs to be specified; and (3) the computed accretion or depletion is extremely sensitive to the head values used in the' computat ion, Results of this technique indicate that the boundary inflow, which' occurs along al I but the northern edge and part of the northeastern CGrner of' the valley, totals about 17 ft3/s, Boundary outflow to the South Platte River' valley is about 9 ft3/s, Assuming that the system is nearly in a steady-state condition (a reasonable assumption, considering the lack of changes in the' water-level data and the results of the Beaver Creek model), net discharge. from within the valley is 8 ft3/s. Known recharge from surface-water appli-: cations in much of the northern part of the modeled area would indicate that: total withdrawals annually certainly exceed 8 ft3/s, I I . To confirm the occurrence of recharge and pumping, another simulation! run was made with all of the hydraul ic heads at the boundary nodes being held' constant. The drawdown configuration (fig. 3IJ) resulting from this simulation: shows the decline in water levels in the northwestern part of the modeled' area if there were no recharge in those areas to maintain heads as they are: nOW, likewise, a rise in water levels would occur in the southern part of; the modeled area if there were no pumping causing the lower levels that were: measured. I I I i , i , Many simulations were made to provide planners with a variety of con-: ditions for consideration during the design of the project, Alternatives' using different combinations of proposed recharge, pumping, and time periods. included: L- Predicted Conditions in Beaver Creek Valley 59