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Rule 6.4.7 Exhibit G- Water Information 22. Rule 6.4.7(3) requires that the applicant provide an estimate of the project water requirements including flow rates and annual volumes for the development, mining, and reclamation phases of the operation. This would include volumes of evaporative loss expected during maximum pit disturbance as well as during final reclamation. Please address. 23. On page G-5, the applicant states that Western Mobile has installed a ground water monitoring system in the areas of current and future mining to obtain baseline information on the water table, ground water quality, and surface-ground water relationship, as well as to monitor possible future impacts due to mining. The applicant has provided hydrographs for various surface water stations monitored to date. Depth to ground water and water quality data collected was not included in the application. Please provide this information, if available. Also, please clarify whether the operator will maintain the current hydrologic monitoring program throughout the mining & reclamation phases of [he operation or whether there will be additions or deletions to the current program. If hydrologic monitoring is to be continued throughout the mining and reclamation phases, the Division is particularly interested in verifying the surface and ground water stations to be monitored, frequency of monitoring, parameters to be monitored, and procedures for submittal of monitoring data. The applicant should also include any surface water stations or wells outside the proposed permit area that will be included in the hydrologic monitoring program. Please address. 24. On page G-5, the applicant states that it will be necessary to relocate and/or remove irrigation ditches at the Lyons site, including Gross Private !#I, Montgomery Private ditch, and several laterals of the Smead Ditch. Please indicate which ditches will be removed and which ditches will be relocated. Please provide engineering designs for the relocated ditches and provide a revised map to show their proposed relocations. The operator will also need to provide written consent from the owners of the various ditches for their removal and/or relocation. 25. On page G-l, the applicant states that the majority of the site lies within the boundazies of the 100- yeaz flood plain of the main stem and south branch of the St. Vrain River. The schedule provided on page D-6 of the application indicates that mining and reclamation will occur over 12 year blocks and will encompass approximately 36 yeazs. During this 36 year period it is likely that flood events for the main stem and south branch of the St. Vrain River of various return intervals (frequencies) will occur. On page G-6, the applicant states that overflow structures will be provided for each of the ponds to be constructed within ttte reclaimed area. Please provide engineering designs for each of the structures to be constructed and provide the location of the structures on a revised map (Reclamation Plan Map or Water Information Map). Please indicate whether the overflow structures will be temporary or permanent structures. If temporary, the structures should be designed to safely pass the peak flow expected from a 25-year storm event from their respective watershed. If petirtanent, the structures should be designed to safety pass the peak flow expected from a 100-year storm event from their respective watershed. The operator should use the greater of the peak flows expected from a 6-hour vs. 24-hour storm event and should provide supporting hydrologic calculations. The operator should also describe the watershed used to size the structures and specify whether the watershed includes the entire basin for the main stem and south branch of the St. Vrain or just the immediate area within the site itself. a