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• 4.2 Peak Discharges and Volumes <br />The eastside and westside diversion systems consist of buried pipe and open <br />channels as previously described. These systems will provide conveyance for ail runoff <br />resulting from the 100yr-24hr event intercepted above the waste pile on the east basin <br />and at the canyon mouth diversion on the west basin. The peak discharge is <br />approximately 5.9 cfs for the east basin and 4.6 cfs for the west basin. <br />• <br />The portion of the total watershed which will be collected and routed into <br />sedimentation ponds consists of 4.74 acres of disturbed yard, 14.6 acres of waste pile <br />area and 21.31 acres of adjacent undisturbed area resulting in 40.65 acres. The <br />undisturbed areas were routed into the sedimentation ponds because of the difficulty in <br />diverting them around the yard. The 10yr-24hr volume for the west pond is 1.96 AF and <br />for the east pond 0.19 AF. The 25yr-24hr peak inflow to the west and east ponds are 4.9 <br />cfs and 0.4 cfs respectively. These values are summarized in the following table. <br />DESIGN DISCHARGES AND VOLUMES <br />Basin 100yr--24hr <br />Peak Discharge 25yr-24hr <br />Peak Discharge 10yr-24hr <br />Volume <br />East Basin 5.9 cfs ----- --- <br />West Basin 4.6 cfs ----- ---- <br />Contaminated <br />Waste Pile Ditch 4.4 cfs ----- ----- <br />West Pond, Yard -- inflow 4.9 cfs <br />outflow 4.8 cfs 1 1.96 AF <br />East Pond, Yard. -- inflow 5.1 cfs <br />outflow 5.0 cfs 2 0.19 AF <br />West Hillslope 0.9 cfs ---- <br />(~) outtiow over spillway, does not include flow to east pond through connector pipe <br />(2) inflow directly to east pond from subbasin /combined inflow <br />5. Drainage Structures <br />U <br />5.1 Pipes and Channels <br />The drainage system consists of 9 sections of open channel (reaches 1, 2, 5, 6, 8, <br />10, 1 Oa, 12 and 13} and 5 sections of pipe (reaches 3, 4, 7, 9, and 11). All pipes were <br />6 <br />January 1998 ~; <br />