2006-05-22_REVISION - M1982015 (3)

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16. In conformance with Rule 6.4.7(2)(b), please provide a representative cross sectional diagram for each of the three (3) mined lakes which adequately depicts the features of the alluvial aquifer within the affected land and surrounding azea. The cross sectional diagram should be drawn to scale and provide the following information: • Existing reclaimed excavation(s) and lake high water mark(s) • Groundwater (peizometric) surface • Proposed slurry wall installation • St. Vrain Stream Channel (from top of North Bank to top of South Bank) • 100-Yeaz Floodplain boundaries (existing & proposed) & elevations • St. Vrain Creek - Floodway boundaries • Any existing registered wells within 600 feet of the slurry wall installation • Ordinary high water mark of the St. Vrain River • Invert of the St. Vrain River • Significant wetlands, and/or woody riparian vegetation 17. In conformance with Rule 3.1.6(1), please quantify the vertical and horizontal extent of impact to the groundwater surface and normal groundwater recharge or flow pattern(s) upon completion of the slurry wall installation. It is the Division's experience with other slurry wall installations that there is typically a "mounding" and "shadowing" effect. These impacts are typically quantified through groundwater modeling and field verified through a groundwater monitoring program. Also, please describe and show on a map the location of any water feature (well, spring, wetland, riparian vegetation) or permanent man-made structure (leach field, sewer line, highway bridge support, septic tank, etc) that is within the scope (radius) of influence of either mounding or shadowing, and assess the impact to such feature or structure. Finally, please describe the mitigation measures that will be employed to minimize the impact on the various water features or man-made structures. 18. Please provide a map which depicts the lateral extent of the "floodway" and 100-year floodplain for the St. Vrain River, elevation of the 100-year flood surface, location of the existing reclaimed lakes, and proposed slurry wall installation. 6,4.12 EXHIBIT L -Reclamation Costs 19. In conformance with Rule 6.4.12(1), please provide itemized costs for each spillway, culvert, or other hydraulic structure to be installed. 6.4.13 EXHIBIT M -Other Permits and Licenses 20 Please indicate the status of the applicant's 404 Permit application with the US Army Corps of Engineers, particularly with respect to the proposed plans for fill of several or more wetlands within the permit azea.