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5533 modeled area, The general tendency for hydraulic conductivities to decline towards the east may be correct, but it seems unlikely that the change is so abrupt. . For the Laramie-Fox Hills aquifer, consider the reasonableness of, and justification for, using hydraulic conductivities in the eastern portions of the basin that are orders of magnitude higher than in most of the western portions of the basin, This east-west trend is opposrte the trend shown for the other three aquifers, and may not be consistent with the referenced Raynolds conceptual geologic model of the Denver basin, Local Well Model After an initial review of the local well model, our peer review group made a few recommendations for improving the model, These recommendations included increasing the assumed distance from pumping wells to the constant-head boundary and reconsidering the time parameter (originally 30 days) so that rt is more representative of length of the peak pumping season, Both of these recommendations were followed, A comparison of pumping test results with the predictions based on the local well model is shown in Table 4.5 of the draft report, The resu~s show that at least for aquifer condrtions that existed at the time of the tests (Le" with confined aquifer conditions), on average, the local well model predictions appear to be quite reasonable, The model overpredicted the pumping rate of some wells, underpredicted it for others, but the average difference between predicted and observed pumping rates was not large. Since the model is used to estimate the number of required water supply wells, matching results from individual well tests is not nearly as important as being close, on average, to the pumping test results. Consequently, the comparisons tabulated in Table 4,5 seem favorable, ( Concem had been expressed that with existing aquifer conditions the local well model predicts well capacities that are much higher than the pumping rates in any of the existing water supply wells. A possible explanation that has been offered that may explain at least part of this difference is that the local well model was applied using the assumption that the pumping water level in each well is near the bottom of the well, thereby indicating a maximum pumping capacity, However, in most of the more productive existing wells, the pumping water level is probably well above the bottom of the well. Hence, in the more productive portions of the aquifer, actual well capacities may be higher than the current pumping rates. Perhaps the greatest uncertainty regarding the accuracy of the local well model predictions has to do with its accuracy as the aquifer becomes unconfined, For example, Figure 4.4 of the draft report shows that the typical capacity of a well in the Arapahoe aquifer is predicted to fall from about 530 gpm in 2000 to only about 120 gpm in 2050, Similarly, the capacity of the Lower Dawson wells is predicted to drop from about 120 gpm to only 20 gpm. Modest errors in these estimates would be of little consequence when the well capacity is hundreds of gallons per minute, but when the predicted capacity drops to only 20 gpm, or even 120 gpm, such errors would have a more significant effect on the estimated number of wells. However, the effects of model bias would alleasl be consistent. Hence, if the model overpredicts the number of required new wells, it would tend to overpredict the number for all of the water supply alternatives. However, caution is warranted in considering the actual number of predicted wells for the various alternatives. For example, Table 4.15 of the draft report ( . Page 3