Laserfiche WebLink
DATE: July 10, 2008 <br />TO: Travis Marshall <br />FROM: Kate Pickford <br />RE: Hydrology Review of Lyster Oil Company, Inc., Lyster Pit, File No. M-2008- <br />009 Moffat County <br />The Division has reviewed the responses to the hydrologic adequacy comments for the Lyster Oil <br />Company, Inc. 112c permit application for the Lyster Pit, File #M-2008-009, and submits the <br />following comments. <br />The Applicant has committed to installing monitoring wells at the site to monitor groundwater <br />levels, primarily in the vicinity of the Deep Cut Ditch. The report submitted by Water Resource <br />Consultants, LLC indicates that it believes there will be little or no additional water loss from the <br />ditch, due to sediments contained in the ditch, the loam suspected to be located around the ditch, <br />and the fact that the ditch already sits above the water table. Therefore the Division does not <br />understand the proposal to monitor water levels in the vicinity of the ditch if the conditions <br />described above can be confirmed. Alternatively, the Applicant should submit a plan to identify <br />whether the ditch is experiencing water loss during the time the pit is dewatered. The proposed <br />monitoring method should also address mitigation measures that will be incorporated should the <br />monitoring identify increased water losses. Alternatively, if the ditch company is unconcerned <br />about potential water losses to the ditch during dewatering, the Applicant may submit an <br />agreement signed by the ditch company indicating such, which would eliminate the need for <br />monitoring. <br />The Applicant has not proposed any monitoring wells to monitor drawdown in the vicinity of the <br />wells located near the site. The Applicant has indicated that 2 of the 4 nearby wells are <br />completed in a deeper aquifer and should not be impacted by the dewatering activities. If the <br />Applicant can show that the remainder of the nearby wells are completed in a deeper aquifer, the <br />Division will not require installation of monitoring wells to protect these wells. The Applicant <br />must, however, determine that none of the wells are alluvial aquifer wells in order to eliminate the <br />need for monitoring wells. If any of the wells are alluvial aquifer wells, monitoring wells will <br />need to be installed to monitor the groundwater levels in between these wells and the pit. A <br />monitoring plan to include trigger points and mitigation measures must also be submitted to the <br />Division. <br />The Applicant should consider whether any additional impacts may occur as a result of <br />dewatering, such as impacts to any subirrigation near the site. If the Applicant can show that no <br />nearby areas rely on subirrigation, the Division may determine there is no need for monitoring <br />wells relative to these areas. <br />If any monitoring wells are needed at the site, the Division does not agree with the report from <br />Water Resource Consultants, LLC that states it believes that 4 to 6 months of groundwater level <br />monitoring is adequate to determine the background water levels and the seasonal fluctuations. <br />The Division maintains a standard 5 quarter monitoring plan to determine background water <br />levels and therefore believes the 5 quarter plan should be used in this case.