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MMRR Quarry, M-2004-067 Response to June 30 Adequacy Review (as amended) August 19, 2005 Page 8 16. On Revised Exhibit C-28 sedimentation pond C is labeled as permanent and appears from the construction drawing to be smaller that sedimentation pond 8, which is contradictory to the values for the ponds shown in the table on the drawing. Please address. Please see the attached report submitted by Ramsay M. McDermid. 17. The McDermid memorandum (page 2) indicates historic peak flows from the 100-year event in each of the basins are 81 cfs (West Basin), 166 cfs (East Basin) and 55 cfs (South Basin). None of the revised exhibits delineate these drainage basin boundaries. Also, please confirm the sedimentation ponds are capable of handling these storm event Flows. Please address. Please see the attached report submitted by Ramsay M. McDermid. 18. The March 15, 2005 Memo from Mike McDermid to Alex Schatz quantifies historic peak flows in cfs from a 100-year storm event from various drainage basins within the contributing watershed at the MMRR Quarry site. These volumes are used in the sizing of al! permanent drainage features. The applicant will need to clarify the period of time the historic peak flow apply to, ie: 24-hour storm, 6-hour storm, 2-hour storm, etc. and provide a discussion for why this storm period was selected. Given the site location and its capacity for frequent high intensity-short duration events, it is appropriate for the applicant to provide an evaluation of the various storm periods and select the period which will generate the highest peak flow and corresponding peak flow velocity. The applicant will also need to specify the peak flow velocity expected from each contributing watershed during the 100-year, _ hour storm event. The applicant will need to verify that all permanent spillways and drainage channels are designed to withstand the peak velocity expected from such an event. For those applications where riprap installation will be necessary, the applicant will need to provide the details for riprap sizing such as the riprap D 50 and thickness of the application. Please provide. Please see the attached report submitted by Ramsay M. McDermid. 19. The March 15, 2004 Memo from Mike McDermid to Alex Schatz references the 10-year, 24- hour storm event as the design storm event for temporary drainage structures. Please provide an assessment of the 10-year, 24-hour storm; 10-year, 6 hour storm; and 10-year, 2-hour storm event for the watershed encompassing the proposed MMRR Quarry and indicate which storm event produces the highest peak Flow and corresponding peak Flow velocity. The applicant will need to verify which of these storm events produces the highest peak flow and velocity, and then provide the corresponding peak flow and flow velocities for each contributing watershed used in the design of temporary spillways and/or drainage channels. The applicant will also need to verify that any new drainage culverts (24" or 48') to be installed are designed to convey the peak flow expected from either a 10-year, _ hour or 100-year, _ hour storm event, whichever is more appropriate. Please see the attached report submitted by Ramsay M. McDermid. 20. The March 15, 2004 Memo from Mike McDermid to Alex Schatz references 4 attachments, ie: hydrology calculations, pit slope report, diversion channels design, road design parameters. Please provide these 4 attachments. Please see the attached report submitted by Ramsay M. McDermid