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Modifying a well to operate under lower groundwater conditions. This could <br />include deepening existing wells or lowering the pumps. All work would be done <br />at Lafarge's expense with the exception of replacing equipment that was non- <br />functional prior to mining. <br />If existing wells cannot be retrofitted or repaired: replacing the impacted well <br />with a new well. <br />Providing flood irrigation to address concerns over impacts to sub-irrigated lands <br />adjacent to the site. <br />If a groundwater mitigation action is required, Lafarge will notify the Weld County <br />Engineer and the DMG of the condition, action taken, and result. <br />TREES <br />Impacts to trees will be mitigated through monitoring and if necessary, managed recharge of the <br />alluvial aquifer or watering of the trees. Monitoring wells will be installed' between mine cells <br />and azeas of sensitive vegetation. The frequency of monitoring will be as described above. If <br />the water level data indicates that the water table beneath the trees declines by more than 2 feet <br />of the pre-mine water levels during the growing season, or the trees show signs of stress, Lafazge <br />will commence mitigation measures within 10 days of the determination of impacts. Lafarge <br />will hire a qualified expert to perform regulaz inspections of offsite vegetation. The inspection <br />frequency will be twice per yeaz, once in the spring and once in the summer. The mitigation <br />measures would be by one of two methods: <br />1) Watering of the trees using dewatering water, or <br />2) Managed recharge of the alluvial aquifers. The managed recharge would be <br />accomplished using basins positioned between the mine cells and the trees. The <br />basins would be filled with dewatering water. The basins would extend along the <br />perimeter of the mine cell between the cell and the trees. The basins would be <br />excavated to the top of the gravel (about 5-8 feet) with side slopes of 2:1 <br />(horizontal:vertical). The bottom width would be about 4-8 feet. <br />' Lafarge has already installed several wells in the area. However, additional wells will be necessary to monitor <br />these areas. <br />Lafarge West, Inc. Riverbend - $ - August 2005 <br />Groundwater Monitoring and Mitigation Plan H:WIJ7_012_02\Grow~dxaterUtirertxndGWMOn&MifigationPlan8-26-0S.doc <br />