Laserfiche WebLink
TRM—CDOT Class 3 <br /> CDOT's TRM Class 3 is an effective permanent turf reinforcement mat for slopes up to 4-5% <br /> (CDOT 2014). Some of the Outer Ditch slopes are steeper than that but this foundation, coupled <br /> with some the additional methods is felt to be effective. <br /> Riprap <br /> The riprap that will be installed along the banks next to Brookfield were calculated by two <br /> methods. Riprap for mild slopes was calculated using UDFCD's method for mild slopes (UDFCD <br /> 2016). See Attachment 12. <br /> Riprap needs for steeper slopes was calculated by the CSU method referred to in UDCFD's <br /> Criteria Manual (CSU 1988). The summary page for these calculations is given in Attachment 13. <br /> Please note that void filled and soil filled riprap were avoided so that credit could be gained for <br /> water flow through the riprap. <br /> UDFCD calls for a certain way of tying the toe of the slope down (burying the bed by three feet <br /> at an angle in the channel). This was felt to be excessive and would be a construction challenge. <br /> Instead, HMD utilized a method offered by the State of New York where a buried toe was <br /> provided (New York 2005). <br /> Drill Seeded <br /> General Shale will be drill seeding all exposed earth with a method and seed mix that has proved <br /> effective for several years at the mine. <br /> Check Dams <br /> General Shale decided to add check dams in the steep channel upstream of the hydraulic jump. <br /> The design methodology utilized is one contained in CDOT Guidance. The slope adjustment in <br /> the CDOT guidance was utilized. That slope is 0.00958%slope. The theory is that the steep <br /> slopes are divided into a series of flat slopes(0.00958%slope)with sub-critical flow and minor <br /> energy dissipation where water flow over the crest of the check dam. <br /> Hydraulic Jump <br /> The check dams,when working properly,should totally dissipate the energy developed by water <br /> rushing down the steep slopes. However,General Shale and HMD decided to locate another <br /> energy dissipating device at the end of the steep slope run. The hydraulic jump laced in the <br /> HM1116 <br /> 11 07/30/2017 <br />