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i• <br />unit dry weight of the lift reaches a value not less than 90% of maximum unit dry weight <br />attained in a laboratory compaction test in accordance with the specifications of ASTM <br />D 698, Method D. <br />Where the embankment is placed against the existing slopes, the slopes will be <br />benched and scarified down to a firm dense base as the new fill is being placed. <br />Material so loosened will be mixed with the new fill and the resultant mix blended firmly <br />into the slope. <br />When rock or rocky material is used for embankment, placement shall be in <br />layers not exceeding the maximum size of the rock present, and in no case shall lifts <br />exceed 30 inches in depth. Rock layers shall be compacted by routing the spreading <br />equipment and loaded hauling equipment over the entire width of the fill until <br />compaction is obtained. <br />Temporary erosion control measures will be implemented during the construction <br /> <br /> <br />of the haul roads. Straw bales or other alternative sedimentation control devices will be <br />placed along the edge of the embankments. Immediately after construction is complete <br />the area disturbed will be seeded and mulched to promote a reduction in the rate and <br />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 />Permit Renewal <br />2-9 <br />09/03 <br />