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Fourth Quarter 2003 Groundwater Monitoring Report
<br /> Boyett Petroleum,419 S.Main,Manteca,CA
<br /> Page 5
<br /> Table 4: Groundwater Elevation Data (December 31, 2003)
<br /> Monitoring Well TOC Elevation' Screened Depth to Groundwater
<br /> Interval b s) Groundwater Elevation2
<br /> MW-2 35.97 15-25 21.58 14.39
<br /> MW-3 36.18 15-25 22.15 14.03
<br /> MW-4R 35.21 10-25 20.88 14.33
<br /> MW-6 36.07 10-25 21.72 14.35
<br /> MW-7 36.42 10-25 22.46 13.96
<br /> MW-8 36.43 10-25 22.72 13.71
<br /> MW-9 35.95 40-50 21.54 14.41
<br /> MW 10 36.09 10-25 22.14 13.95
<br /> MW-1 1 36.15 29-39 21.81 14.34
<br /> EW-1 36.23 29-39 21.91 14.32
<br /> 'TOC Elevation: Elevations are referenced to NAD83 datum,NGS Benchmark HS 4486. j
<br /> =Groundwater Elevation:Elevations are measured from the top of the well casings and are referenced to the benchmark indicated above.
<br /> Monitoring wells MW-1,MW-4,and MW-5 were destroyed October 29,2003
<br /> Monitoring wells MW-4R,MW-10,and MW-11,and extraction well EW-1 were installed October 30,2003
<br /> All measurements arc in feet.
<br /> The groundwater elevation contours (Figure 7, attached) estimated using depth to water measurements
<br /> from the site monitoring wells (except MW-9, MW-11, and EW-1) collected by Condor on December 31,
<br /> 2003 indicate a relatively gentle groundwater gradient to the north. An estimated groundwater gradient of
<br /> 0.0057 ft/ft towards the north was calculated using water level data from monitor wells MW-2, MW-6,
<br /> and MW-8. Historic groundwater gradients reported for the site have been highly variable (Table 5,
<br /> below; Figure 8, attached).
<br /> Table 5: Historic Groundwater Gradients
<br /> Date Approximate Flow Direction Monitoring Wells Utilized for Groundwater
<br /> and Groundwater Gradient Gradient Calculations
<br /> September 1, 1999 0.002 ft./ft.-Northwest
<br /> December 10, 1999 0.0010 ft./ft. -Northwest MW-1, MW-2,MW-3
<br /> March 27,2000 0.0 16 ft./ft.-Northeast MW-1, M W-2,M W-3
<br /> June 23,2000 0.0021 ft./ft. -Southeast MW-1, MW-2,MW-3
<br /> September 8,2000 0.004 ft./ft. -Southeast MW-1, MW-2, MW-3
<br /> December 2000"* 0.0021 ft./ft.-Southwest MW-2, MW-6,MW-8
<br /> March 5,2001* 0.0061 ft./ft.-Northeast MW-2,MW-6,MW-8
<br /> June 4,2001* 0.005 ft.lft.-Northwest MW-2, MW-6,MW-8
<br /> September 10, 2001* 0.0072 ft./ft.-Northwest MW-2,MW-6,MW-8
<br /> September 26,2002 1,30.0058 ft./ft- Southwest MW-2, MW-6, MW-8
<br /> December 27, 2002 0.0036 ft./ft. -Northeast MW-2, MW-6,MW-8
<br /> March 21,2003 0.0008 ft./ft.-South MW-2, MW-6,MW-8
<br /> June 25,2003 0.0085 ft./ft,-Southwest MW-2, MW-6,MW-8
<br /> July 22,2003 0.0094 ft./ft. -Southwest MW-2, MW-6,MW-8
<br /> August 19,2003 0.0089 ft./ft. -Southwest MW-2, MW-6,MW-8
<br /> September 30, 2003 Not Calculated MW-2 dry; MW-6 and MW-8 pEgeLddr �
<br /> October 31,2003 Not Calculated Lack of Data
<br /> _November 26, 2003 0.0315 ft./ft.-Southwest - _ MW-3, MW-4R,MW-10 - ---
<br /> December 31, 2003 0.0057 ft./ft. -North MW-2, MW-6,MW-8—
<br /> Date inferred
<br /> — C.uuuui uegnn eundueting quarterly groundwater monitoring at the site
<br /> — Well collars surveyed;elevations are referenced to NAD83 datum NGS Benchmark HS 4486
<br /> • *- Condor recalculated gradient
<br /> CONDOR
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