Laserfiche WebLink
.o�G9 <br /> GROUND ZERO ANALYSIS, INC. ' o � <br /> 1714 Main Street <br /> Escalon,California 95320 <br /> Telephone:(209)838-9888 �P�icFsq�,y <br /> Facsimile:(209)838-9883 <br /> December 20, 2005 <br /> Mr.Nuel Henderson <br /> San Joaquin County Environmental Health Department <br /> 304 E. Weber Ave., 3rd Fl. <br /> Stockton, CA 95202 <br /> Subject: Workplan for Deep Monitoring Well Installation <br /> 102 South Wilson Way, Stockton, California(Figure 1) <br /> Dear Mr. Henderson: <br /> This Workplan is submitted on behalf of the Knowles Family 1993 Revocable Trust in response to <br /> the San Joaquin County Environmental Health Department(EHD)directive letter dated August 31, <br /> 2005. In the directive, EHD requested the installation of a deep (C-Zone) monitoring well in the <br /> underground storage tank leak source area. EHD proposed that the new well should be screened <br /> in the approximate interval of 110-120 feet below grade, similar in construction to existing well <br /> MW15C and within a sandy interval identified in two source area CPT borings. The new well <br /> will be identified as monitoring well MW17C. The sections below describe the proposed <br /> methodology of drilling, sampling and constructing the well. <br /> WORKPLAN <br /> New monitoring well MW I7 will be constructed in the source area at the approximate location <br /> shown on Figure 2. Since well MW17C will be screened in a potentially clean, or minimally <br /> contaminated, water-bearing zone, but will pass through highly contaminated shallower <br /> groundwater, precautions will be taken to ensure that the annular seal will be adequate to prevent <br /> cross-aquifer contamination. The proposed drilling and construction methodology is intended to <br /> minimize the possibility of inter-aquifer transfer of groundwater during drilling and after <br /> completion of the well. The boring will be drilled with mud rotary equipment and conductor <br /> casing will be set across the potentially contaminated upper aquifer zones. The well will be <br /> completed with a screened interval from approximately 105-115/110-120 feet below ground <br /> surface (bgs) depending upon the precise location of the sandy bed in the boring. <br /> G:\GROUNDZE\ROEK\CLOSURE\Workpl-\MW 17CWorkplm.doc <br />