2024-02-26_PERMIT FILE - M2024005

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Sedgwick County Road and Bridge Gravel Pit Page 14 112(c) Operation Reclamation Permit February 25, 2024 7.0 EXHIBIT G—Water Information 7.1 Groundwater The operation is not expected to directly affect groundwater systems. Below is the reasoning used to come to this conclusion. In the geotechnical engineering report in Appendix A, there is a minimum depth to groundwater of 150 ft. This report was done in 1993 and water levels in the Ogallala aquifer have fallen since then so there still should be a minimum depth to groundwater of 150 feet below the ground surface. There is also bedrock at a minimum depth of 40 feet below the site. The only potential source of groundwater contamination from the gravel pit is sedimentation in stormwater runoff directly entering the groundwater. It can be assumed that there will be no groundwater contamination from the mining operations since the depth of the water table is sufficient to allow natural filtration of particulates before stormwater runoff encounters the groundwater system. 7.2 Surface Water/Erosion Control There will be minimal effect on surface water systems the majority of the time since the permeability of the soil is moderately high to high (Ksat=0.2-6 inches/hr) and it is a semi-arid climate (average annual rainfall is 16.7 inches). The operation may affect surface water systems during heavy rainfall. Stormwater runoff control/sedimentation control detention ponds will be built downslope of mining areas to prevent loose material from the mine site from entering surface water systems.All final grading will be done to prevent erosion. There will be three sedimentation control detention ponds to collect runoff for any disturbed areas, piled material, or operating surfaces. Stockpiles of soil will be stabilized against erosion in accordance with the mining plan. Figure 7 shows the locations of the proposed sedimentation basins. Z:IProjectslSedgwick County12023 Gravel Pa Perm,ttmg1Permtt AEC