Laserfiche WebLink
analyses are indicative of errors that would cause meaningful error in the proposed <br /> lines derived from the model delineating the division between tributary and <br /> nontributary ground water. The State Engineer finds the analyses provide clear and <br /> convincing evidence in support of the State Engineer's adoption of rules identifying <br /> water withdrawn from the undifferentiated Wasatch Formation, middle and lower <br /> Wasatch Formation, Iles Formation of the Mesaverde Group, Williams Fork <br /> Formation of the Mesaverde Group, and undifferentiated Mesaverde Group, within <br /> delineated areas of the Piceance Basin, to be nontributary for purposes of his <br /> administration and permitting of wells pursuant to C.R.S. § 37-90-137(7). <br /> Rules for Piceance Basin—Deep Formations. The State Engineer finds there is clear <br /> and convincing evidence supporting his adoption of rules identifying water withdrawn <br /> from the Mancos, Dakota, and Morrison Formations, within certain delineated areas <br /> of the Piceance Basin in Rio Blanco, Garfield, Mesa, Delta, and Pitkin Counties, <br /> Colorado, to be nontributary for purposes of his administration and permitting of <br /> wells pursuant to C.R.S. § 37-90-137(7). <br /> The State Engineer's finding is based upon testimonial evidence provided regarding <br /> analyses performed by Mark Palumbo, M.S. using the Glover-Balmer method for <br /> purposes of determining the timing of depletions to stream flow resulting from <br /> withdrawal of ground water from the subject formations. The State Engineer finds <br /> that this testimony, as well as the additional evidence in the record, provides clear and <br /> convincing evidence that the rules identify nontributary areas in manner that is <br /> consistent with C.R.S. § 37-90-103(10.5). <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 model to be <br /> appropriate. The State Engineer finds the storativity values relied upon in the <br /> analyses to be reasonable. The permeability values were based upon a review of both. <br /> the literature and of site-specific data obtained from wells completed in the subject <br /> formations. The State Engineer finds this site-specific data resulted in the use of <br /> appropriate values within their individual models. <br /> Certain parties challenged the use of a single permeability value for each formation <br /> derived from the numerous data measurement points. The State Engineer finds the <br /> evidence to be clear and convincing that the use of such a single value was <br /> appropriate. Although permeability within a formation may vary to some extent, <br /> ground water traveling through the formation will travel through areas of both <br /> relatively higher and lower permeability. Accordingly, to the extent that the <br /> permeability numbers may vary within a formation, the effective permeability of the <br /> formation is accurately reflected through use of a geometric mean of the measured <br /> Produced Nontributary Ground Water Rules 2 CCR 402-17, Statement of Basis and Purpose <br /> -25- <br />