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. <br /> To:Dale Leach <br /> Date: October 2014 <br /> Page 2 <br /> stabilization at the toe (Photo 4). The fill was calculated using rough field measurements <br /> -the road eroded away along a 55 foot span on a slope about 24 feet high,which would be <br /> filled back to existing slope which is about 1.7:1 -> 760 cy of fill. <br /> • A second area of the ditch embankment has a channelized erosion path approximately 20- <br /> feet wide and 1-foot deep requiring about 35 cy of fill (20*1*47 ft/27=35 cy). <br /> • Approximately 3,500-feet of ditch has 2-6 feet of sediment build up,totaling around <br /> 11,280 cy,requiring removal (Photo 5; —6.5' wide across top of sediment- 3,500 feet * <br /> approximately 87 square foot cross section/27=—11,280 cy). <br /> • Approximately 140 feet of ditch downstream of the bridge requires repair,excavation, <br /> and embankment replacement. <br /> • The downstream side of the ditch (as the water exists the headgate) is washed out for <br /> approximately 10-feet. This area previously was constructed with large rock and local <br /> soils(Photo 2). <br /> • Rock, gravel, loam soil fills downstream of the headgate are washed out, requires <br /> approximately 200-300 cy of fill to restore previous ramp to the top of the diversion <br /> structure (Photo 2). <br /> • Dirt road roundabout is washed out, an area of about 3,000 square feet(Photo 6). <br /> • Steel safety rails embedded in the concrete along the top of the headgate have been <br /> washed away or significantly bent. <br /> • A tree growing right at the end of the diversion structure on the south side of the river has <br /> fallen over ripping out its root ball and exposing the south side end of the diversion. This <br /> will eventually allow water to erode rocks and soils beneath the diversion structure <br /> (Photo 7). <br /> Immediate Repairs <br /> Work to be completed prior to the first winter freeze would include: <br /> • Removing debris, loose silt and sediments from the top and sides of the headgate. <br /> • Rock, gravel, loam soil fills downstream of the headgate are washed out, requires <br /> approximately 200-300 cy of fill to restore previous ramp to the top of the diversion <br /> structure. Surrounding materials can supply some of the fill. <br /> • Replace any small areas of washed out headgate foundations with River Fill, described in <br /> the fill section below. If large areas of the foundation are washed out temporary River <br /> Fill should be placed. The need for permanent concrete fills will be evaluated in the <br /> spring. Detailed notes and photos of any temporary fills should be kept. <br /> • Fill in the area at the south side of the river immediately adjacent to the diversion where <br /> the tree root ball has been torn out with the River Fill described in the fill section. Rock <br /> immediately downstream, near where a power line pole has been washed out, can be <br /> pulled back to fill the space. Additional off-site non-concrete rock fill may be needed. <br /> Leave space to re-plant a sapling tree in this area in the spring. <br /> R:\L.ouden_Ditch\Louden_Ditch\Products\2013_Flood\Engineering Rec Letter\10032013_Louden_Ditch_Eng_Assesment_Letter.docx <br />