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R SECOR Ii (__� .� Figures 3, 3A, 4, 4A, and 5 illustrate stratigraphic profiles across the site area based on the formations encountered during drilling operations on site. 3.6 Hydrostratigraphic Units U Water -bearing horizons observed within the study area included zones within the 71 unconsolidated fluvial deposits. For well designation purposes, the underlying aquifer zones +_i have been identified as the A -Zone (shallow zone extending to approximately 65 ft bgs), the B - Zone (65 to approximately 90 ft bgs), the C -Zone (from 100 to 110 ft bgs), and the S -Zone (115 to 210 ft bgs) (see Figure 5). 3.7 Horizontal Hydraulic Gradient The cumulative groundwater measurements collected during the monitoring events are summarized in Table 2. The calculated relative elevations were used to infer the groundwater flow direction and gradient within the study area. Fluctuations in the flow direction for zones A '= and B are displayed on the rose diagrams in Figure 6 and 7, respectively. Based on static water level (SWL) measurements collected from the shallow (A -Zone) groundwater monitoring wells, the inferred groundwater flow direction in the shallow zone of the aquifer across and south of the site is oriented in a southeasterly direction under an average hydraulic gradient of 0.01 foot per foot (ft/ft). Based on SECOR's observations, the predominant flow direction of the A -Zone is to the southeast, which at times is influenced by pumping from the City of Lodi Municipal Well 18. Due to influence from the onsite groundwater extraction wells, groundwater flow direction toward the northwest has also been observed in the A -Zone. SWL measurements collected from B -Zone wells indicate that an inferred groundwater flow direction in the intermediate zone of the aquifer is to the southeast under an average hydraulic gradient of 0.01 ft/ft. Groundwater elevations at MW -10C and MW -19C support the assumed southerly groundwater flow direction of the C -Zone. An insufficient number of groundwater monitoring wells are located within the S -Zone to be able to infer groundwater flow direction and gradient. Flow direction and gradient information for the S -Zones beneath and south of the site are not available. However, based on United States Geological Survey (USGS) and State of California reports on the hydrogeology of the area, SECOR assumes the predominant flow direction of these zones is also to the south. Also, groundwater elevations observed at monitoring wells MW -10C and MW -19C support the assumed southerly groundwater flow direction in the C - Zone. 95775 NFAR REPORT Finatdoc 7 SECOR International Incorporated