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6.4.7 Exhibit G -Water Information <br /> (1) The operation will affect groundwater systems through evaporation and <br /> pumping. Predicted depletions to groundwater which are tributary to the Big <br /> Thompson River will be mitigated through design and implementation of a <br /> Temporary Substitute Water Supply Plan (SWSP). A well permit and <br /> associated SWSP will be acquired and approved by the Colorado Office of <br /> the State Engineer (SEO) prior to exposure of any groundwater onsite. <br /> (2) (a) Surface water structures are shown in Exhibit C1, Pre-Mining Plan Map <br /> (b) The sand and gravel deposit to be mined is an alluvial aquifer tributary to <br /> the Big Thompson River. <br /> (c) Water from dewatering operations is routed to sediment pond to allow for <br /> settling of suspended sediment. A stormwater management plan has been <br /> prepared for the site which identifies BMP's to prevent pollution to surface <br /> waters due to stormwater runoff. <br /> (3) Under full operation, the project will consume approximately 5-10 acre-ft/ <br /> year due to evaporative loss of exposed groundwater in dewatering trenches, <br /> water lost within the mined product and water consumed for dust control. <br /> (4) The replacement source for all depletions to the Big Thompson River will be <br /> either fully consumable water rights leased by the operator from the City of <br /> Loveland or other water rights owned by the operator decreed for <br /> augmentation. <br /> (5) The applicant has applied for and received a NPDES Stormwater Discharge <br /> Permit. The permit number is TBD. <br /> Hydrologic Balance <br /> The construction of the Compacted Clay Liners as specified in the reclamation <br /> plan may have the potential to create groundwater mounding up-gradient of the <br /> proposed reservoirs. For the purpose of determining if mounding will occur, the <br /> applicant proposes the installation of groundwater observation wells along the <br /> upgradient property boundary as shown in Exhibit F — Reclamation Plan - <br /> Sheet 1. Wells OW-1 through OW-9 will be installed following completion of the <br /> project permitting process. Existing wells EW-1, EW-2 and EW-3 will also be <br /> utilized to observe groundwater elevations. <br /> The applicant proposes monthly observations of groundwater elevations <br /> (observations) for all wells prior to mining and monthly observations following <br /> reclamation. If the reclamation condition water levels are shown to occur at less <br /> than 30% of historic, then no mitigation shall be required. If the reclamation <br /> condition water levels increase above 30%, then a perimeter drain will be <br /> engineered and installed to mitigate groundwater mounding. <br /> Amen Aggregate Resource <br /> Specific Exhibits <br /> Page 23 of 44 <br />