ARCHIVED REPORTS_[REV] MAY & JULY 2014 RCSI

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2-10 curing and screening area. and/soreening/ final product storage area isw i ll be up to approximately 2.97 acres. As described above in this section, the composting pad will be constructed of native earth. The permeability of soils below the surface of the composting pad is low. Operations will be suspended, if necessary, during periods of wet weather to prevent damage to the composting pad or the surface will be paved with gravel or asphalt if the economics justify the higher cost. Due to the low-permeability of native soils and depth to groundwater, monitoring of soil moisture is not warranted. In accordance with WDR Order No. R5 -2014- 0006. the soil in the upper one foot of the composting pad and compost storage pad areas are tested and if necessary. conditioned and compacted to achieve 1 X 10.5 cm /sec vertical hydraulic conductivity.soil sampling for ammonia, nitrates, metals and trace organies Gould be Gonduoted to eonfirm the lael< of movement of these eonstituents . Gi'o'en the slow annual mmlOment of groundwater at this site, soils eould be removed and disposed of if movement of po ll utants '...,as found th rough soil monito ri ng . The site and pad will have a minimum of a one percent slope and wW indrows will be constructed normal (or perpendicular) to the slope, so there will be no standing water on the pad. Detailed design calculations are presented in Appendix HA. 2.1.6 Drainage Control Indicate on a map the locations ofpninary drains, befn:J5, ew. Prm'ide a descn'pt/on of all surfaee and subsurface drains, which are to be used to control water froR'J areas OR, or adjacent to the compost/n§! site inch:Jdin§! the types of pfOtectJ~{e dikes, berms, aRd levees plaRRed for this facility. ,In additioR, please specify how the site will be desigrJOd aRd constructed to limit pORding, infiltlVt/OR, inUFJdatic)R, washout, etc. Run-on to the composting site is prevented by an existing berm located on the eastern and a portion of the south edges of the site. Slopes generally decrease from the northeast to the southwest. An existing ditch prevents run-on from the north. The grading and drainage plan (Figure 6) shows the proposed grading of the RRF/Compost Facility. The grading plan is the same for all of the potential composting alternatives. A one percent minimum grade is provided at all pOints in the composting site. The composting wW indrows are arranged normal to the slope to allow free drainage and minimize ponding. The site is sloped to drain to two ditches designed to carry the water from the 25-year, 10- minute duration storm (0.25 inches, 1.5 inches per hour) assuming all the water that falls on the composting site runs off. The ditches will carry the water to a sedimentation basinretention pond designed to hold the net average annual rainfall during months where rainfall exceeds evaporation (5.67 inches) assuming all the water that falls on the site runs off. This exceeds the 25-year, 24-hour rainfall event (2.28 inches). As described above in Section 2.1.5. th is seat ion , the composting pad will be constructed of native earth. The permeability of soils below the surface of the composting pad is low. Operations will be suspended, if necessary, during periods of wet weather to prevent damage to the composting pad or the surface will be paved with gravel or asphalt if the economics justify the higher cost. Due to the low-permeability of native soils and depth to groundwater, monitoring of soil moisture is not warranted. In accordance with WDR Order No. R5-2014-0006. the soil in the upper one foot of the composting pad and compost Forward Compostlng Facility SWT Engineering Report of Composting Site Information -May 2014 z:\projects\aliied waste \forward V esource recovery facility \5 yr perm it rvw 2013·14Vcsi 2014\text\se c 2 · revtr.doc