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Water level data from City of Lodi water supply wells and monitoring wells indicate that groundwater occurs at a depth of about 45 feet below the LNC property and ranges from about 45 to 55 feet bgs south of the LNC site. Historically, groundwater flow in the first water bearing zone has been identified to be primarily to the south, although the local gradient may vary from south-southeast to south-southwest over time (SJCFCWCD, 2004). Groundwater levels within the first water bearing zone tend to drop rapidly with distance south of and away from the Mokelumne River. These groundwater levels have a flattening of gradient further south in the center portion of the city of Lodi. There are insufficient data to evaluate naturally occurring vertical gradients beneath the LNC site. However, local groundwater flow directions may be significantly affected by pumping centers and high capacity wells (i.e., the City of Lodi's municipal water supply wells) on a seasonal basis. 5.2 Source Area Evaluation This workplan and technical scope of work has been based on addressing only VOCs on the LNC site and immediate surrounding property owned by Ackel. The identified area is depicted by the yellow dashed line as shown on Figure 11. No other area or areas have been contemplated to be evaluated, investigated or remediated. 5.3 Volatile Organic Compound Migration Volatile organic compounds (VOCs) dissolved in groundwater will generally migrate away from a source area primarily by advection with some migration by mechanical dispersion and chemical diffusion(Geomatrix, 2003). VOCs dissolved in groundwater typically migrate at a rate slower than groundwater. The amount of this decrease in migration rate or retardation(R) is a function of the organic carbon content (fo,,) of the sediments, the organic/carbon partitioning coefficient M ain\D:AEnvironmentaI\LN CV\10152007.wpd 31