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Mr. Robert McClellan October 1 , 2010 Page 5 The perimeter monitoring probes along the southwestern compliance boundary (GP-10 through GP-13) will also be monitored monthly for six months, using a field meter, for methane, carbon dioxide, oxygen, balance gas, and vacuum levels to evaluate the effects of the added LFG extraction and SVE wells on the probes. LANDFILL GAS PERIMETER MONITORING PROBE INSTALLATION WORK PLAN As stated above, SCS, on behalf of Forward, submitted to the LEA on March 22, 2010 an Addendum to the previously approved Title 27 Perimeter Probe Monitoring Network for the Southwest Expansion Area, and a response letter on May 17, 2010. The LEA stated in conversations to Forward that prior to implementation of the probe installation, some remedial efforts had to be initiated to control LFG migration in the southwest area of the site. The first part of this Work Plan addresses those remedial efforts. Once those efforts are in place, Forward proposes to continue with the proposed plan submitted in the Addendum, and summarized herein. Background To maintain compliance with the requirements in Title 27 §20925, six LFG perimeter probes will be installed in native soils on the landfill property, along the planned permitted boundary. These proposed probes will effectively replace five current LFG perimeter probes that will no longer be in compliance due to the proposed expansion. Therefore,those five current LFG probes will be abandoned. The perimeter probe abandonment will not occur until the permitted boundary expansion has been approved. The Solid Waste Facility Permit is currently being revised to include the southwestern expansion area as a buffer area. The new probes and expansion area are shown in Figure 1. Installation Criteria Six probes,to be designated GP-8R, GP-9R, GP-l OR, GP-11 R, GP-12R, and GP-28, will be installed in native soils at the approximate locations shown in Figure 1. Probe construction will be consistent with the requirements of Title 27 §20925(d). Table 3 provides estimated well construction details. The elevations and calculated depths are based on the site topographic map (Figure 4), and are subject to change depending on actual conditions encountered. The monitoring probes will be drilled and installed using hollow-stem auger equipment and methods. A certified State of California(C-57) licensed drilling contractor will be contracted to conduct the drilling and well construction activities. • New Probe Locations—All probes will be installed on landfill property, outside of the planned waste area, and near the future permitted boundary. The proposed probes GP-8R and GP-9R will be installed along the southern future permitted boundary; probes GP-11R, GP-12R, and GP-28 will be installed along the western future permitted boundary; and probe GP-IOR will be installed near the southwest corner of the future boundary.