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manner that is consistent with C.R.S. § 37-90-103(10.5). The State Engineer <br /> therefore finds it appropriate to adopt a single rule based upon these analyses to assist <br /> in his administration and permitting pursuant of ground water wells pursuant to <br /> C.R.S. § 37-90-137(7). <br /> First, for reasons previously stated, the State Engineer finds the Glover-Balmer <br /> method is an appropriate method for determining the timing of depletions to stream <br /> flow for purposes of C.R.S. §§ 37-90-103(10.5) and 37-90-137(7). <br /> Second, the State Engineer finds the inputs to the Glover-Balmer models relied upon <br /> by Messrs. Levorsen, Witt, and Bedard to be appropriate. The State Engineer finds <br /> the storativity and permeability values relied upon in the analyses to be reasonable. <br /> In the case of Mr. Levorsen's analysis, the storativity and permeability values were <br /> based upon an extensive review of a detailed site-specific data obtained from core <br /> samples from numerous wells completed in the subject formations. Utilizing a <br /> Klinkenberg adjustment, water permeabilities were derived from the data obtained <br /> from these core samples. A representative reservoir intrinsic permeability was <br /> calculated for each formation using a geometric mean of all Klinkenberg <br /> permeabilities. Less than one percent of the data was excluded in this analysis. <br /> Messrs. Witt and Bedard similarly computed permeability values based upon <br /> extensive analyses of site specific data. The State Engineer finds there to be clear and <br /> convincing evidence that these detailed analyses of extensive site-specific data <br /> resulted in the use of appropriate values. <br /> Certain parties challenged the use by Messrs. Levorsen, Witt, and Bedard of a single <br /> permeability value for each formation derived as a geometric mean of the numerous <br /> permeability measurements. The State Engineer finds the evidence to be clear and <br /> convincing that the use of such a single value was appropriate. Although <br /> permeability within a formation may vary to some extent, ground water traveling <br /> through the formation will travel through areas of both relatively higher and lower <br /> permeability. Accordingly, to the extent that the permeability numbers may vary <br /> within a formation, the effective permeability of the formation is accurately reflected <br /> through use of a geometric mean of the measured values. Moreover, because of the <br /> discontinuous nature of the formations, the evidence is clear and convincing that the <br /> measured permeability values in fact significantly overestimate the actual formation <br /> permeability along any ground water flow path. <br /> Certain parties also argued that the permeability values are likely to vary greatly <br /> between the deeper portions of the formation and the portions of the formation <br /> located at or near the formation outcrops. The State Engineer finds there to be clear <br /> and convincing evidence that this concern does not cast doubt upon the accuracy of <br /> the analyses. The State Engineer found particularly convincing the testimony of <br /> Lesley Evans, P.G., which demonstrated that it is unlikely there would be any <br /> significant variance between the permeability values for the deeper and shallow <br /> Produced Nontributary Ground Water Rules 2 CCR 402-17, Statement of Basis and Purpose <br /> -23- <br />