Laserfiche WebLink
Stantec <br /> L & M OPERABLE UNIT- FOURTH QUARTER AND ANNUAL 2012 SITE STATUS, <br /> REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT <br /> Groundwater Monitoring and Sampling <br /> February 1, 2013 <br /> SPH or sheen has historically been reported in well 2AMW-14 since May 2002 (Table 3, <br /> Figure 9). Historical thickness of SPH in well 2AMW-14 has ranged from 0.02 ft reported during <br /> the first quarter 2005 to a maximum thickness of 2.99 ft reported during the fourth quarter 2003. <br /> Well 2AMW-14 was not assessed during the third through fourth quarters of 2004 due to its <br /> connection to a free product removal system. However, well 2AMW-14 has been accessible in <br /> recent quarters and has contained sheen only. SPH or sheen has historically been reported in <br /> well MW-10 since February 2004 and has ranged in thickness from 0.01 to 3.09 ft (February <br /> 2007; Table 3). Well MW-10 was abandoned in November 2008 due to the City of Stockton's <br /> excavation activities. <br /> Historical measurable thickness of SPH in wells DPE-1 through DPE-13 and MW-40 has ranged <br /> from 0.01 ft (DPE-12, February 2005) to a shallow zone maximum thickness of 11.72 ft (DPE-1, <br /> November 2003). Well MW-40 was abandoned in November 2008 due to the city of Stockton's <br /> excavation activities. All DPE wells were not monitored during 4Q12 in accordance with the <br /> MRP R-5-2012-0805. <br /> A summary of 4Q12 SPH thickness and SPH sheen in comparison to the 3Q12 is provided in <br /> the following table. <br /> SPH removal activities are scheduled to be conducted quarterly (at a minimum) for on and off <br /> Site wells which repeatedly contain measurable thickness of SPH and are not connected to a <br /> free product removal system. It should be noted that these SPH removal activities are typically <br /> performed between quarterly monitoring events (as noted on the table), and are likely to <br /> influence reported SPH thickness. A free product removal system is scheduled to be installed in <br /> early 2013 on the WOTOA property, offsite. Following installation of the system, quarterly SPH <br /> removal in the WOTOA property off-site will cease. <br /> SPH SPH <br /> Well Thickness Thickness Difference <br /> Identification 3Q12 (Feet) 4Q12 (Feet) (Feet) <br /> 2AMW-13 Sheen* Sheen* NA <br /> 2AMW-14 Sheen** NS NA <br /> MW-19 Sheen* Sheen* NA <br /> Definitions: <br /> NA = Not applicable <br /> NS = Not sampled. Inadvertently missed during 4Q12. <br /> SPH = Separate phase hydrocarbon <br /> * = SPH removal occurred prior to groundwater sampling. <br /> ** = Connected to free product removal system <br /> I:\Tidewater\TW Stockton(P2A)\QMRs\2012\4Q12-Ann ual\4Q12 and Annual QSSR QRSR QMR Stockton_FINAL.doc 2.13 <br />