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The existing gate at the site entrance will be preserved. Post closure maintenance of the landfill gas extraction system may require a full-time technician to operate the system. Such personnel would also monitor and maintain the fencing and gates and look for evidence of unauthorized access to the closed facility. 2.4.3 Final Cover and Grading San Joaquin County is planning to close the landfill using an approved ET final cover system, which is an alternative final cover as allowed in Section 21090(a) of Title 27, California Code of Regulations. This closure method does not include a low hydraulic conductivity barrier layer. hnvestigations at the site indicate that there is sufficient soils available to construct the ET cover (JTD Tables 3 and 4, and "Landfill Closure Method Selection Report, Foothill Sanitary Landfill, San Joaquin County, California", September 21, 2004 (revised 3-17-05)). The top deck is designed with a minimum slope of 6 percent. Side slopes will average about 3.4H: IV and will include 15 foot wide benches incorporated into the sideslopes every 50 vertical feet. Due to the preliminary nature of the final grading plan the slopes shown on the plan (JTD Figure 6) are inclined at the average slope and do not show the benches. Slope Stability 19 The stability of the final cover for FSL was reviewed based on the current final grading plan, the final cover components, and the regulatory requirements under both static and seismic conditions. Title 27 CCR Section 21090(a) states that: "Designs hewing any slopes steeper than a horizontal to vertical ratio of three to one, or having a geosynthetic component [binder ¶ (a)(2)J', shall have these aspects of their design specifically supported in the slope stability report... " The proposed maximum slope for FSL is 29% (3.4 to 1), and less than the three to one. Therefore, a slope stability report is not required at this time. However, the County may elect to increase these proposed closure slopes in the future. If so, the County will submit a slope stability report addressing these new slopes as required by the regulations in force at that time. Due to the absence of geosynthetics in the proposed ET final cover, there is no concern that the stability of the final cover is reduced by a geosynthetic component. Class III landfills must be designed to withstand seismic ground motions resulting from the Maximum Probable Earthquake (MPE) at the site. A seismic hazard evaluation was performed Title 27 CCR Section 21090(x)(2) refers to the requirements for the low hydraulic conductivity layer of the final cover. Foothill Sanitary Landfill B-5 Public Works/Solid Waste Preliminary CPCM Plan County of San Joaquin — Rev July 2010