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Where the embankment is placed against the existing slopes, the slopes are <br />benched and scarified down to a firm dense base as the new fill is being placed. <br />Material so loosened is mixed with the new fill and the resultant mix blended firmly into <br />the slope. <br />When rock or rocky material is used for embankment, placement is in layers not <br />exceeding the maximum size of the rock present, and in no case shall lifts exceed 30 <br />inches in depth. Rock layers are compacted by routing the spreading equipment and <br />loaded hauling equipment over the entire width of the fill until compaction is obtained. <br />Temporary erosion control measures were implemented during the construction <br />of the haul roads. Straw bales or other alternative sedimentation control devices were <br />placed along the edge of the embankments. Immediately after construction was <br />complete the area disturbed was seeded and mulched to promote a reduction in the <br />rate and volume of run-off. <br />Drainage <br />The bridge spanning East Salt Creek is on private property near Highway 139 <br />has been designed to safely pass the 100 year storm event, see Appendix M. The <br />flood hazard to the haul road is mitigated by adequate sizing of culverts. This is the <br />subject of a separate report by R. V. Lord and Associates in Appendix M(i). The Lord <br />study does not address the 72" culvert where the haul road crosses over Munger <br />Creek. This culvert must pass the 10-year event which is 225 cfs, see Table 4.5-6. <br />With a HW/D ratio of 1.25 this 72" culvert has the required capacity (ref. Handbook of <br />Steel Drainage & Highway Construction Products). A HW/D ratio of 1.25 means water <br />must pool 18" above the top of the culvert in order to pass the design flow. <br />The haul road from State Highway 139 to the gob pile was maintained in <br />accordance with Rule 4.03.1(6). The road surface was periodically watered and <br />maintained with a motor grader. Gravel was added to the road surface as necessary. <br />Ditches along the roadway were periodically cleaned with a motor grader and the road <br />shoulders were smoothed. <br />RN-05 2-8 09/07 <br />