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Carl Mourrt March 14, 1991 Forge 2 Comment 2) : In the WET report (page 1) it is stated: "Gtsnbired flows fran existing culverts N acrd P as well as half culvert O will be conveyed along the western aryl southern sides of the West Ridge Waste Disposal area in i~roved Channel AA~7J and conveyed to the existing detention pond." It is unclear whether COVCC is going to extend these culverts to proposed Charuiel AA~7J or Create Protected channels fmn the outlets of these culverts to Channel AA~7J. Please provide details as to what COVOC interns to do. Reply 2) : An existing riprap protected c~an*wi will corney water fr~n the outlet of culvert N to the t~,~t reach of t~hanrwl AA. Half- ruud culvert O extends from the r-nichim and SCrBPlring level to disc3~arge directly into c3rarv~el AA. The riprap in d~a~vrel AA has been sized in aowrdanoe with the anticipated 100-year, 24-hour flow event. Flows fr+an culvert P will eventually be conveyed to charuwl EE and be Hooked thrax~ half culvert O. This will be accca~q~lished by grading the area arorud the sewage treatment plant to drain toward channel EE following removal of the plant. Map No. 6A-5D has been revised to show this change in grade. Camtw~t 3): The WET report also states on page 4: "...flows fran the Office, Shop and Waralwuse that currently flora into culvert K will eventually be diverted into cannel T." It is unclear how this will be done even though the present design parameters for Channel AA acv mwc that this well be done. The proposed Map 8-1 shows the culvert K outlet such that water flowing through the culvert enters the natural drainage cannel directly east of designed Channel T. If COVCC plans to extend culvert K or eliminate this culvet"t it should be clearly stated how aryl when these tasks will be done. Reply 3): Cxnrrent plans call for culvert K to be removed during the final abandorm~ent phase of reclamation at the OrG~atti Valley mine. Upon removal, channel U will be reconfigured and resized as necessary to wrrvey flows into channel T. Revised ditch design calculations submitted herein are based upon work generated, by Greystone Development Consultants and approved as TR-9. The resultant drainage schematic pages aryl calculation sheets frwn TR-9 weren't formally incorporated into the permit document. In crier to provide a specific reference for these materials, I propose that they be included in Volume 8 order the tab entitled "Drainage -Design and Location." 'These materials should appear immediately following the OVNII+I Water Tank and Ventilation Shaft Sites S7na11 Area bcemption Application. The new design specifications for channel E~ arrl the calculations for the small temporary ir~oundment by culvert P should be appended to this section. The table of contents for Volume 8 has been revised accordingly and is included with this submittal.