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Facilities that use amendments or additives must have a layer with a permeability of no greater than 1 x 10'or other standard allowed in writing by the regional board. The Compost Facility pad will be constructed of low permeability compacted native soil. It is anticipated that the compacted native soil will provide adequate protection of groundwater. The compost pad area is sized to accommodate each of the selected composting technologies. The pad will be up to approximately 8 acres. The curing/screening/product storage area will be up to approximately 15 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. Soil sampling for ammonia, nitrates, metals and trace organics could be conducted to confirm the lack of movement of these constituents. Given the slow annual movement of groundwater at this site, soils could be removed and disposed of if movement of pollutants was found through soil monitoring. The site and pad will have a minimum of a 1 percent slope and Windrows will be constructed normal to the slope, so there will be no standing water on the pad. Detailed design calculations are presented in Appendix A. .1.7 Dri a Control Indicate on a map the locations of primary drains, berms, etc. Provide a description of all surface and subsurface drains, which are to be used to control water from areas on, or adjacent to the composting site including the types of protective dikes, berms, and levees planned for this facility. In addition, please specify how the site will be designed and constructed to limit ponding, infiltration, inundation, 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. 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 9) shows the proposed grading of the site. The grading plan is the same for all of the potential composting options. A one percent minimum grade is provided at all points in the composting site. The composting Windrows 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 retention 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). Forward Composting Facility Z:\PROJECTS\Allied Waste\Forward\Resource Recovery Facility\Permitting Services\2009 RCSI\RCSI Final 031609.doc; Page 21