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' Groundwater Monitoring and Mitigation Plan for <br />Heit Aggregate Resource Operation-Weld County <br />Aquatic and Wetland Nursery and Coyle Properties <br />5.5 Relocation of Nursery Stock (for AWC only) <br />Nursery stock that is currently sub-irrigated could be moved to the north further away from the <br />area of potential influence from the Heit Pit. Preliminary modeling shows that the extent of <br />drawdown north of the proposed pit becomes small (0.5 feet or less) approximately 1,200 feet <br />north of the pit on AWC property. <br />I' 5.6 Excavation of Area for Nursery Stock (AWC only) <br />An area could be excavated on AWC property to enable continued sub-irrigation with slightly <br />lowered groundwater. <br />5.7 Emergency Pumping <br />If necessary, water from the pit could be pumped to meet an emergency need (e.g., to maintain <br />existing nursery stock). It may be possible to use the existing lake north of the Coyle's house for <br />this purpose on their property. <br />6.0 SUMMARY <br />The preliminary groundwater evaluation completed for the Heit pit found that only relatively <br />small changes in groundwater levels are possible from the operation due to the presence of a <br />slurry wall. However, it is recommended that the groundwater monitoring program in this plan <br />be implemented for the adjacent AWC and Coyle properties. Groundwater measurements from <br />the plan can be used to determine pre-mining conditions, post-mining levels, and for updating the <br />modeling completed in our Mazch 2003 report. <br />If groundwater is lowered by more than 2.0 feet compazed to pre-mining conditions by the <br />operation, this will immediately trigger: <br />1) Cessation of de-watering operations, <br />021-110.030 Wright Water Engineers, Inc. Page 6 <br />' Jufy 2003 <br />