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four times that of the well depth in the landfill interior, and three times the depth of the well for wells near the edge of the landfill. Well depths at the Harney Lane Landfill vary between 36 and 70 feet(Table 1). Based on this,it appears that significant overlap of radius of influence is provided in most areas by the present LFG well system; however, an area of limited influence is noted on the secondary site near monitoring well GW-3 (Figure 2). It is important to note that many more LFG wells are installed along the edge of the landfill adjacent to the migrant labor housing facility. Additional wells were installed to provide maximum control of LFG migration toward the occupied structures. Landfill Cap Continuity The surface of the Harney Lane Landfill was reconditioned in the autumn of 2003. Reconditioning included removing the vegetation from the surface, adding soil as needed to provide drainage, and compacting both the new soil and existing surfaces. After compaction, the surface was hydroseeded for erosion control. Hawk perches and owl boxes were installed to enhance the raptor population, thus reducing the potential for damage to the cap by burrowing rodents. Recompaction and adding soil to the surface increases the continuity of the closure cap, thus increasing the radius of influence of landfill gas wells and the ability to control LFG migration. The surface of the landfill can be easily inspected and,based on recent observations, it appears that the reconditioned surfaces have retained their integrity since reconditioning. Pipe Sizing Criteria In general, a collection system is considered adequate if the blowers can provide sufficient vacuum to overcome the headloss imposed by the piping system under current flow rate conditions. Therefore, it is the pipingiblower system that may be considered for adequacy, rather than the piping as a separate component. Under present operating conditions, the blowers at the Harney Lane Landfill are sufficient to provide all vacuum needed at each LFG well, such that all LFG available at each well can be collected. However, it is useful to evaluate piping as an individual component to assess the appropriateness of design. In this approach, pipes are evaluated according to the design criterion that the capacity of the pipes is that flow rate which imposes 1-inch water column(wc) headloss (Figure 3). Pipes in which the flow rate is less than this maximum design flow rate are adequately sized. Under this evaluation criterion, it appears that the pipes of the Harney Lane Landfill LFG system have at least twice the capacity presently needed. Remediation Plan for LFG Migration rJ San Joaquin County Public Works/Solid Waste Harney Lane Sanitary Landfill Revised December 14,2004