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1 1 1 1 1 1 1 1 1 1 -~- settle out prior to entering the lower reaches of Strain Gulch. An alternate is to allow the runoff from the quarry to follow down the internal access road into the upper opera- ting area. Either a separate sedimentation pond and inlet is required for this runoff in the area immediately below the south quarry access road embankment or facilities must be pro- vided to allow safe passage through the operating area to the east end of the fill where facilities as described in the following paragraph will be provided. Because the road embankment is above the operating area, there will be approximately 24 acres of area which are not controlled by this embankment even with the quarry runoff directed into the sediment pond formed by the road. Runoff from this lower area will collect through the operating area and pass over the end of the fill. Peak discharge under 100- year flood conditions will be approximately 15 to 20 cfs. Zf runoff from the quarry area is taken through the operating area also the flow potential is 30 cfs. Zt is necessary to provide some means at the end of the fill to protect the slope from erosion. The area of the fill has been hydromulched and during the next few years vegetation will be establisheed. Because of the steep slope of the fill it is not considered that the vegetative cover alone will completely stop erosion, particularly from a major storm if the water becomes concen- trated. Figure 3 illustrates two alternative means of protecting the fill slope. The first is to construct a low berm along the edge of the slope a distance of at least 5 feet back from the slope to protect against a slippage failure of the slope. An open channel constructed of grouted riprap will drop the water to the historic channel elevation. This channel could be constructed to resemble a natural mountain stream ii' it is anticipated that it will be used in the reclamation plan. h1 Leo.aartl Rice Consulting Waler Eng neers.lne ' `~