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SMALL AREA EXEMPTIONS Fish Creek Dewatering Site At the dewatering site, sedimentation will be controlled by the use of alternate control systems such as filter fences, gravel filters, and existing vegetation. In reference to the 0.5 ac stockpile located to the southwest of the pond, a berm will be inscribed around the stockpile to direct runoff from the stockpile to the two gravel filters by the stockpile. This will effectively treat the estimated 0.02 AF of runoff from the IO year-24 hour event until the stockpile becomes vegetated. Once this occurs the berm and fdters can be removed. The runoff from the 0.2 acre stockpile adjacent to the transformer will drain to the low area of negative drainage northeast of the stockpile where adequate vegetation exists to provide filtering and treatment of the water. The small azea exemption is shown on Map 26, Fish Creek Borehole Area Facilities and Access Road. The collection ditch that services the ponds and associated disturbed areas will have two gravel filters placed in the ditch to act as a secondary sediment control measure. The gravel filters will be constructed of 3" minus washed gravel, and will be approximately 24 inches in width. The filter will be placed across the ditch and extend halfway up the sides of the ditch. A berm will be placed on the south side of the road leading into the control building. The berm will be located so as to keep drainage from this area from entering the discharge ditch. The berm will provide an area that can act as a sump to hold or direct water from this site. Also, in order to provide access to the dewatering boreholes the two light duty roads will be connected to form a pad between the wells. The available topsoil will be windrowed to the sides of the pad and will be stabilized with the approved seed mixture. The graveled pad and roads are within the confines of the 2.0 acre small area exemption area as shown on Map 26, Fish Creek Borehole and Facilities and Access Road. In reference to the boreholes and control building area, collection berms will be inscribed downslope of the area to direct an estimated 0. l2 of of runoff from the 10 year-24 hour event to either the adequately sized low containment area west of the area, or to a pair of rock filters on the north side. Fish Creek Ventilation Borehole Another small azea exemption exists at the Fish Creek Ventilation Borehole. Sediment control in this 0.6 acre area of disturbance will be accomplished by a vegetative filter. However, until the vegetation becomes reestablished, the 0.06 a/f of nmoff from the 10 year-24 hour event will flow to the collection around the Fish Creek Borehole ponds, and it will be treated by the gravel filters located in the ditch. The small azea exemption is shown on Map 26, Fish Creek Borehole area Facilities and Access Pond. Sandstones Power Substation Sediment Control for this area (less than one acre) will be comprised of a perimeter containment berm temporary diversion ditch and gravel fdter(s) sufficient to treat the estimated 0.06 AF of runoff from the 10 year-24 hour event. The location of this small area exemption is shown on Map 39 (Substation and Powerline Location). This SAE was expanded slightly in Fall 1993 to allow the drilling of a replacement borehole into the mine, which was in turn used for drilling of a water supply/monitoring well underground (FCM #2). The expansion of the SAE entails extension of the berm to the west to encompass the slight amount (approximately 50' x 50') of additional disturbance. Any topsoil stripped will be windrowed/temporarily stockpiled adjacent to the pad. Following completion of the well work, a portion of the expanded azea maybe reclaimed, with remaining topsoil being added to the existing topsoil stockpile. The topsoil and reclaimed azea will be seeded and stabilized using the pastureland seed mixture. ~`'~,1~~~~"JyL JUN 2 8 2000 PR 99-05 2.05-80 8/27/99