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demonstrated expertise with respect to the Denver-Julesburg Basin, to be more <br /> convincing than these assertions. The objecting parties relied also upon conclusions in <br /> the 1988 Belitz and Bredehoeft study to challenge Dr. Weimer's conclusions that the <br /> faulting system established a hydraulic disconnect between the delineated nontributary <br /> area and the formation outcrop. In particular, Messrs. Sanchez and Mefford noted that <br /> Belitz and Bredehoeft recognized the existence of the Golden Fault, but concluded that <br /> the evidence did not establish that this faulting system continued north of Boulder. Mr. <br /> Mefford noted that the Belitz and Bredehoeft study relied upon modeling to conclude that <br /> north of Boulder there was recharge from the outcrop area to deeper formations within <br /> the Denver-Julesburg Basin. Drs. Weimer and Snow provided convincing testimony in <br /> response to this challenge. Dr. Snow demonstrated that Belitz and Bredehoeft model did <br /> not establish the necessity of assuming the existence of ongoing significant recharge into <br /> the Denver-Julesburg Basin. Moreover, Dr. Weimer testified that information obtained <br /> subsequent to the 1988 publication of the Belitz and Bredehoeft study, including Dr. <br /> Weimer's own 1997 publication, conclusively demonstrates that a faulting system does <br /> continue north of Boulder. The State Engineer finds Dr. Weimer's testimony to be the <br /> best evidence of the actual geologic structure of the Denver-Julesburg Basin. <br /> The objecting parties also argued that there was no evidence demonstrating that the <br /> delineated nontributary areas lie east of the geologic faulting creating the hydraulic <br /> disconnect between the subject formations and the formation outcrop areas. However, <br /> Dr. Weimer testified that the proposed nontributary lines, which lie at a minimum a <br /> distance of 0.8 miles from the outcrop formations for the Lower Pierre Shale Formation <br /> (a highly impermeable shale formation), and are otherwise located at least 2.5 miles from <br /> the formation outcrop area, are at a more than sufficient distance from the formation <br /> outcrop areas to ensure that the delineated nontributary area in the Rules includes only <br /> formations located within the hydraulically disconnected Denver-Julesburg Basin <br /> downthrown fault block, and excludes any formations located within an upthrown fault <br /> block that may be hydraulically connected to the formation outcrop areas. In addition, <br /> the State Engineer has included in the final version of the Rules specific language <br /> providing that the rule applies only to groundwater withdrawn by wells drilled to <br /> formations within the Denver-Julesburg Basin downthrown fault block. The State <br /> Engineer will continue to presume as tributary that ground water withdrawn by wells <br /> drilled to formations within an upthrown fault block. <br /> The objecting parties questioned whether the State Engineer may rely upon a geologic <br /> analysis in determining whether to consider certain areas nontributary for purposes of his <br /> administration and permitting of wells pursuant to C.R.S. § 37-90-137(7). The State <br /> Engineer concludes that he may rely upon a geologic analysis to make such <br /> determinations. Colorado statutes define nontributary ground water as ground water <br /> the withdrawal of which will not, within one hundred years of continuous withdrawal, <br /> deplete the flow of a natural stream at an annual rate greater than one-tenth of one <br /> percent of the annual rate of withdrawal. Evidence that there is no hydraulic <br /> connection between ground water located within a particular formation and the waters <br /> within any natural stream is relevant to the determination whether withdrawal of <br /> Produced Nontributary Ground Water Rules 2 CCR 402-17, Statement of Basis and Purpose <br /> -31- <br />