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The fords will be constructed by excavating the existing road surface to create a <br />15% slope into the stream channel where the slope will be 20% below the high water <br />level of the design storm. Although this is steep, the fords are only intended to provide <br />occasional access to the area and are not intended for daily access. The general <br />design includes an eight foot wide road surface and 1 H:1 V side slopes. <br />Upper Road <br />The upper portion of the road will require a more extensive reconstruction of the <br />original channels. In most cases, the original channel was filled during construction of <br />the mine road. Normally, the flow from the channel was diverted along the road in a <br />ditch to a culvert which directed the flow to the outslope of the road and then to the <br />channel in the bottom of Munger Canyon. Eight ephemeral drainages, labeled A <br />through H in Figures 3.1-2 through 3.1-7, cross the road. The boundaries of these <br />drainage basins are shown on Figure 3.9-11. Table 3.9-3 shows the results of peak <br />flow analysis for the drainages and the channel flow characteristics. The reclaimed <br />channels are shown in cross sections on Figures 3.1-5 through 3.1-7. <br />The channels were designed so that the flow would not cause erosion by <br />designing a channel that will be wide enough so the peak flow will remain very shal{ow. <br />Actually, most of the channels will be excavated to the original channel, which will <br />probably had channel bottoms formed in the solid rock that forms the base of the road <br />and the slope below the road. The analysis of the channels took the "worst case" <br />approach that the rock below the road would not be encountered and the channels <br />would be made of the soil in the area. The entire length of Channels A-H will be rip <br />rapped, see Table 3.9-3 for rip rap size requirements. <br />Rip-rap keys will be installed at the top and bottom of each reclaimed channel <br />except for those areas where rock outcrop is present. These rip rap keys will ensure <br />that the entrance and exit of each reclaimed channel will not erode during high flow. <br />The rip-rap keys will be a two foot wide by two foot deep slot dug into the channel <br />bottom on both sides of the reconstructed channel. The keys will be filled with one foot <br />top size rip-rap. <br />TR-22 3-15 03107 <br />