2024-03-01_PERMIT FILE - C1983059 (2)

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• Water Quality Standards and Effluent Limitations The plan for protection and control of the drainage and sediment described above provides that the surface drainage of the disturbed area within the permit area will be passed through a sedimentation pond, dugout pond or sediment fences. The sediment pond and dugout pond will be constructed and maintained to contain runoff resulting from a 10 -year, 24-hour precipitation event for a sufficient time to allow solids to settle and for treatment if necessary. The accumulation of sediment in the ponds will be monitored monthly. In addition, grab samples of water will be collected from the pond discharge to measure the various parameters in meeting the applicable Colorado and federal water quality standards. The sedimentation pond and dugout ponds are designed, constructed and will be maintained to effectively trap sediment from runoff resulting form a 10 -year, 24-hour precipitation event. Drainage from the loadout area, after retention and/or treatment by the sedimentation control system, is not anticipated to exceed the effluent limitations of any federal or Colorado agency requirements. • Diversions The drainage and sediment control plan described provides for temporary diversion of surface runoff within the immediate site. Temporary ditches, as shown on the Sedimentation Control and Small Area Exemption Map (Map 14), will divert runoff from the disturbed areas to sediment control structures and, in other cases, will be used to divert runoff from the undisturbed areas away from the disturbed area. Temporary diversions will be constructed to pass runoff from the precipitation event of a 10 -year, 24-hour recurrence interval. The diversions will be constructed with a minimum gradient to pass the design flow and will be revegetated with grasses or lined with appropriate riprap material if necessary. Upon completion of the loadout activities, temporary diversions will be reclaimed as required. Channel lining riprap and energy dissipators will be used when necessary. TCC does not anticipate that there will be any excess material resulting form the construction of diversion ditches. . 2-05 - 21 Rev. 10-30-92