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KLE7NFELDER <br /> �Bn9hlYeaPle.NI9ht SduU'om. <br /> The concentrations of nitrate as N in the shallow groundwater monitoring wells (MW-5 <br /> and MW-2) and the dewatering discharge samples exceeded the California Maximum <br /> Contaminant Level (MCL) of 10 mg/I in drinking water as expressed in Section 64431 of <br /> Title 22 of the California Code of Regulations §64431 22CCR. <br /> For a summary of the results previously obtained, please refer to Table 8 under the <br /> "Tables" tab of this report. A comparison of the concentrations of the water samples <br /> obtained from the monitoring wells is shown in Chart 8, also under the "Tables" tab of <br /> this report. <br /> jPast data show that the nitrate concentrations in much of the shallow perched <br /> monitoring well samples were in excess of the State of California Maximum <br /> Contaminant Level [MCL] for nitrate-nitrogen. <br /> Based on Kleinfelder's "Report Submittal, Additional Subsurface Investigation, <br /> Norman's Nursery,' dated December 31, 1998, it appears that the shallow perched <br /> water is not continuous between MW-2 and MW-5. Therefore, it is not technically <br /> appropriate to conclude that the nursery has raised the concentration in the perched <br /> aquifer as it passed beneath the nursery. Rather, due to the apparently low-permeability <br /> silts and clays present, the sporadic occurrence of the perched groundwater may <br /> suggest multiple areas of perched groundwater conditions. This is also consistent with <br /> an alluvial and overbank depositional environment. Therefore, channel deposits would <br /> be sporadic in their occurrence and generally be within finer grained overbank <br /> sediments. Additionally, the reason for high concentrations of nitrate above the MCL <br /> upslope (east) of the nursery is unknown, but may be indicative of other sources of <br /> nitrates in shallow groundwater or regional groundwater quality problems. <br /> 5.1.3 Deep "Main" Aquifer <br /> Depth-to-water in the three deep monitoring wells during the third quarter monitoring <br /> event ranged from 145.25 (DP-2) to 157.64 (DP-1) feet below the tops of the monitoring <br /> well casings. The groundwater elevations ranged from -22.37 (DP-3) to -16.39 (DP-1) <br /> feet msl. <br /> 9 <br /> 7226.E02ISTO12R0693 <br /> Page 23 of 42 September 11, 2012 <br /> 11 <br /> Copyright 2012 Kleinfelder <br />