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Ms. Suzanne lanzen <br />March 71, 2005 <br />Page 2 oj4 <br />to be an increase in water leve] in the well of less than 'h foot (see Table-5). This is consistent <br />with our experience with similar sites in the area. The combined effect of the lining of Gell 1 <br />and the reclamation of Ce11.2 as wetlands will not increase the extent of the mounding effects on <br />the well. Further, there is a small natural drainage between Cell l .and the well. If groundwater <br />elevations increase, this drainage will provide a natwal means of alleviating any such increase. <br />Alternatively, the drainage could be deepened slightly which would allow for control of the up- <br />gradient mounding. <br />Cells 1 and 2 in Phase 2, and Cell 1 in Pliase 3 of the mining operation will all be used as silt <br />ponds and reclaimed as wetlands. There aze only two wells in the vicinity of these cells, permit <br />nos. 128682 and 12259, and both are owned by Lafazge. We also note that there are an <br />'additional three wells, permit nos. ] 147, 1145 and 232943, located in the immediate vicinity of <br />Phase 4-that may be impacted. However, these wells aze also controlled by Lafarge. <br />Finally, Ce11 2 in Phase 5 will be used as a silt pond and reclaimed as wetlands. There. is an <br />existing well (permit no. 4180) located immediately to the north of the cell, which is controlled <br />by Lafarge. <br />To the extent that reclamation of the silt ponds changes the groundwater flow in the area, the <br />only potential adverse effects to structures not owned by Lafazge, exist with respect to the well to <br />the southeast of the site_(permit no. 163521). Based on the groundwater model and our <br />experience with similar sites in the azea, these effects will be limited to an increase in water <br />levels in the well less than 1 foot above existing water levels. Lafazge will commit to. monitoring <br />the. groundwater levels surrounding the site, and in particular the. azea immediately to -the <br />sottheast of the site for two years following reclamation of Phase 1 to determine if there are any <br />adverse impacts to well Permit 163521. If monitoring of the groundwater elevation shows an <br />..increase in the water table coupled with a physical injury to the well, Lafazge will commit to the <br />above described mitigation with respecfto the drainage between Phase 1 and the well. <br />14.. Due t6 the potential for permanent impacts to ground water, the applicant may need to <br />take permanent mitigation measures such as installing French drains. The applicant <br />should consider this eventuality and respond to the concern. <br />Lafarge recognizes that the reclamation of the site will cause modifications to the natural flow of <br />groundwater in the area. These changes aze most significant from the lining of certain areas of <br />the site and from silt ponds reclaimed-as wetlands. In general; the effects of reclama{ion of the <br />site will be increases in the water table. elevation up-gradient, and decreases in the water table <br />elevation down-gradient of these aeeas.. As described above, the effects of the modification of <br />the groundwater flow in the area from the silt ponds on existing structures will be minimal, and <br />what effects there aze Lafarge will commit to the necessary. mitigation measures. <br />With respect to the areas that will be lined after reclamation is completed, these aeeas include <br />-only Phases 1 and 4. The groundwater modeling shows that the change in water table elevations <br />