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February 27 1 9 9 7 -3- 963 -2178 <br />• TABLE 3 <br />HYDROGRAPH RESPONSE SHAPE MRS) AND <br />(MAX) LENGTHS OF OVERLAND FLOW <br />::::::::::::.;;:.;:.::.;:::::... <br />i :es::lesa:.t6an.ar..e. t6 5—% o>:::.: .;:.;; <br />>:.;;:;.;:.;:.;:.;:.;:.;. es:: aver:: Zs° to :<:: >:::: >:: >:: >:: >:: >:::: >::: <br />xx <br />Oak Brush, etc. <br />M <br />300 <br />M <br />300 <br />Bare Soil (loose) <br />M <br />300 <br />F <br />300 <br />Bare Soil (compacted hardstands <br />F <br />300 <br />F <br />300 <br />and roads) and vegetated areas <br />subject to disturbance by traffic <br />Graveled Areas <br />F <br />300 <br />F <br />300 <br />Trix,N - m = Meam <br />F = Fast <br />TABLE 4 <br />CONTROL PRACTICE FACTORS <br />• <br />Cut Slopes Assessed as protected with Soil 0.03 <br />Guard, considered conservative as <br />field performance might approach <br />0.001 or better. <br />Fill slopes and Topsoil Storage Pile Assessed as Hydromulched 0.64 <br />slopes Seeded. <br />Graveled roadways and bench or Gravel areas are assessed as 0.05 <br />pad surfaces providing 100% cover. <br />For all sites, based on prior experience by MCC with BMP's for sediment control, sediment <br />control will be accomplished using a combination of silt fences and straw bales. The <br />vegetative filter was modeled to show that it can be an effective means of secondary sediment <br />control. Neither silt fences nor straw bales are evaluated as contributing factors in the SAE <br />effluent analysis, although in actual practice these structures will be used as the primary <br />sediment control structures for the SAE's. <br />Fill slopes are analyzed as seeded and mulched. Cut slopes are protected with Soil Guard <br />(trade name of sprayed protective duff). <br />SedCAD + does not model vegetative (brush) litter as a filter. These structures were equated <br />to grass filters. The natural vegetation of the sites is either open meadow or oak brush with <br />chokecherry and serviceberry. There is a layer ( minim um of 2 inches) of brush litter of the <br />ground. However, flows and velocities are so low that the litter would probably remain <br />stable and in place, or rapidly dam up in collections of debris. The ground cover (vegetative <br />8\61:\9 612 1 7812 1 7 8EM2.LTR Golder Associates <br />