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Ditch D-D2 <br />Ditch D-D2 is formed when the flow from ditch D-D1 and ditch D-E1 join below <br />sediment pond C. From the intersection of the two flows the ditch becomes a V-Ditch <br />that must be capable of handling the combined flow from the two ditches (1.79 + 14.62) <br />= 16.41 <br />The following information is generated from the use of the computer program Haestad <br />Methods FlowMaster I version 3.43. The ditch side slopes are 1.5h:1v, Manning's n = <br />03. <br />Ditch Flow Velocity <br />Flow cfs Grade Depth fps <br />16.41 2% 1.5 5.1 <br />16.41 10% 1.1 9.3 <br />Construct Ditch D-2 two feet deep to allow for freeboard, The section with the 10% <br />grade will require gunnite riprap or riprap and concrete lining for erosion protection. <br />Culvert C-D1 <br />Culvert C-D1 is located in ditch D-D2. The culvert must be 30" in diameter to handle <br />the 16.41 cfs flow. Ditch D-D2 must be constructed at least 30"deep al the transition <br />between the ditch and culvert <br />Drainage Area E <br />Drainage area E is the upland area located above the haul road that provides access to <br />the gob pile. A berm will be constructed along the south side of the road to contain <br />run-off to the site. A single ditch will be constructed on the north side of the road to <br />handle the flow from drainage area E. The peak flow for this area is 1.79 cfs. <br />Ditch D-E1 <br />Drainage area E is the upland area located above the haul road that provides access to <br />the gob pile. A berm will be constructed along the south side of the road to contain <br />run-off to the site. A single ditch will be constructed on the north side of the road to <br />Ditch Flaw Velocity <br />Flow cfs Grade Depth fps <br />1.79 2% 0.65 2.90 <br />Construct ditch D-E1 1.5 feet deep to allow for freeboard. Alternative sediment control <br />features will be installed in the ditch to trap sediment before it leaves the site. <br />Culvert C-E1 <br />Culvert C-E1 was deleted from the design Jan. 1998. <br />PR-07 EXH-8 -12 2/03 <br />