Laserfiche WebLink
subject formations. The State Engineer finds this use of data supported by the <br /> literature and by site-specific measurements resulted in the use of appropriate values <br /> within the individual models. <br /> Fourth, the State Engineer fords the peer review of the NSJB finite difference models <br /> to be additional evidence that the NSJB finite difference models are capable of <br /> accurately delineating nontributary areas within the Northern San Juan Basin. In <br /> particular, the State Engineer finds convincing the testimony of Phillippe Martin, <br /> P.G., C.P.G., a hydrogeologist with many years of personal experience with ground <br /> water models, Colorado water issues and Colorado water law. The State Engineer <br /> finds Mr. Martin's testimony provides additional evidence that the NSJB Model was <br /> developed in a conservative manner using accepted and supported values and <br /> methodologies. <br /> Fifth, the State Engineer finds the review of the NSJB conducted by Staff of the State <br /> Engineer to be evidence that the NSJB finite difference models are capable of <br /> accurately delineating nontributary areas within the Northern San Juan Basin. Staff <br /> for the State Engineer agreed that the conceptualization and modeling approach were <br /> appropriate, that standard modeling practices and procedures were followed, that the <br /> information used in the models was appropriate, and that the models could be used to <br /> determine the locations of nontributary boundaries. <br /> Staff did have questions with respect to certain details regarding implementation of <br /> the models. Staff questioned whether the active area of the models covered the entire <br /> outcrop area. Based on this comment, the active areas of the models were revised. <br /> Staff agreed that, based upon these revisions, the active area of the models <br /> appropriately covered the outcrop areas. Staff for the State Engineer also questioned <br /> whether river cells were included for all river reaches. Based on this comment, the <br /> models were adjusted to add additional river cells. Staff questioned whether the <br /> model storage values for the outcrop areas appropriately reflect unconfined <br /> conditions. Appropriate adjustments were made to the storage values for outcrop <br /> areas. <br /> Upon review of these revisions, Brian Ahrens, P.E., supervisor of the State Engineer's <br /> Modeling Branch and an employee with over 30 years of experience with the State <br /> Engineer's Office, including extensive experience with respect to review of <br /> nontributary determinations, agreed that the NSJB finite difference models could be <br /> used to delineate nontributary areas for the subject formations. Mr. Ahrens further <br /> supported adoption of rules finding the areas delineated by the NSJB finite difference <br /> models to be nontributary for purposes of the State Engineer's administration and <br /> permitting of wells pursuant to C.R.S. § 37-90-137(7). No party disagreed with Mr. <br /> Ahrens careful and studied assessment. <br /> Produced Nontributary Ground water Rules 2 CCR 402-17, Statement of Basis and Purpose <br /> -28- <br />