Laserfiche WebLink
II. DESIGN CONSIDERATIONS <br /> The monitoring perimeter soil gas wells are designed to account for following site <br /> factors as specified in Title 27, section 20923. Best management practices identified <br /> by California Integrated Waste Management Board were also followed. <br /> A. Site Soil Conditions <br /> Local soil and rock conditions do not require special design features in the soil gas <br /> wells. The site materials from the surface to 300 feet in the landfill vicinity consist <br /> of alluvial deposits of two formations, the Laguna and Mehrten Formations. The <br /> Laguna Formation consists of consolidated gravels, sandstones, and siltstones. <br /> The Mehrten Formation consists of sandstone and siltstone, with conglomerate <br /> layers, claystone and mudstone. During well installation, sand lens layers will not <br /> be blocked. <br /> B. Hydrogeologic Conditions <br /> 1 Hydrogeolgic conditions at the disposal site do not require special design features <br /> in the soil gas wells. Groundwater near the landfill property is continually being <br /> recharged by percolation of surface waters, which originate in the Sierra Nevada <br /> and adjacent foothills. Depth to groundwater ranges between 204 feet and 270 <br /> feet. Groundwater elevation ranges between 46 feet to 61 feet MSL. <br /> Groundwater elevations fluctuate less than one foot seasonally. The groundwater <br /> gradient is 0.0015 foot per foot to the southwest. <br /> C. Locations of Buildings and Structures Relative to the Migration Monitoring <br /> Perimeter <br /> Adjacent land use and inhabitable structures within 1 000 feet of the disposal i <br /> � posa site <br /> are primarily agriculture and livestock grazing. <br /> At present, there are two residential houses located off-site near the northwestern <br /> property corner of FSL (Figure 1). The existing refuse footprint is more than <br /> 2000 ft from these houses. These residential houses will be considered <br /> "off-site structures" and will not be monitored for methane concentration. <br /> On-site structures within the monitoring perimeter, such as the scale house, <br /> maintenance building, manager's residence and other on-site residences within <br /> the landfill property limits, will be monitored for methane concentration (Figure 1). <br /> Locations of buildings and structures relative to the migration monitoring perimeter <br /> do not require special design features in the monitoring wells. <br /> D. Man-Made Pathways <br /> There are no man made pathways for the transmission of landfill gas off-site near <br /> FSL. <br /> 1 Foothill Sanitary Landfill 4 County of San Joaquin <br /> Landfill Gas Monitoring Plan Department of Public Works <br /> Solid Waste Division <br />