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All landfill surface water is routed to one of three sedimentation basins see <br /> Drawing 9. The sedimentation basins for the existing Forward Landfill are located° <br /> in the southwest corner of the site, on either side of the South Branch. The <br /> sedimentation basin for the existing Austin Road Landfill is located southwest of <br /> the existing Austin Road Landfill. Water collected in the sedimentation ponds is <br /> sampled in accordance with the site's Stormwater Pollution Prevention Plan <br /> (SWPPP) before it is discharged to the North or South Branches. <br /> The erosion control measures-incorporated in the site design include the following: <br /> • Collection and control of runoff, diverting it away from highly erodible areas. <br /> • Construction of intermediate and final landfill slopes with drainage benches at <br /> intervals designed4o,control sl e,xur4off,vAocites and..volumes. <br /> • 'Hydroseeding with fast germinating drought-tolerant grass seed on <br /> intermediate surfaces that will be exposed for more than 180 days and all <br /> surfaces that are at final grade. Seeded surfaces will be watered until growth is <br /> well established. <br /> Proposed landfill slopes for the three major areas of the Forward Landfill were <br /> evaluated using the Univer°saf-Soil Loss Equation (USt,E,),*e Drawing 11).1).-The <br /> evaluation method determines the potential for soil erosion based on the rainfall <br /> and runoff factor, the soil erodibility factor, the topographic factor derived from the <br /> slope gradient and length, the cover and management factor, and the support <br /> practice factor. The evaluation indicates that the average soil loss will be <br /> approximately 1.0 ton per acre per year for each area evaluated whichis.;below <br /> the two tons per acre per year allowed by the CIWMB. The vegetative layer of the <br /> final soil cover will be seeded with native grasses to protect the upperlayer of soil, <br /> and to minimize erosion. <br /> 5.2.6.2 REALIGNMENT OF LITTLE JOHNS CREEK <br /> The North Branch of the South Fork of Little Johns Creek is currently located to the <br /> south of the existing Austin Road Landfill footprint (see Drawing 2). For the future <br /> Forward Landfill, this creek will be realigned to the north and west of the existing <br /> Austin Road Landfill footprint. This proposed realignment increases the overall <br /> length of the creek by three percent, with a proportionate change in slope, or <br /> grade, of the channel.. The creek will exit the landfill site at essentially the same <br /> 40 location at which it now exits. The new realigned creek will provide the same <br /> Forward Landfill JTD 5-10 <br /> L:\Allied\2000.193\Reports\finalj td:Sec-5.0:08/2 2/01 <br /> BRYAN A.STIRRAT S ASSOCIATES <br />