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0 0 <br />Ms. Vicki McCartney <br />April 21, 2005 <br />Page 4 <br />Monitoring Well Installation <br />Following completion of the CPT and direct -push borings, SECOR will supervise the <br />installation of four, 2 -inch diameter groundwater monitoring wells. Three of the wells will be <br />constructed with 20 feet of screened interval and situated such that a portion of the <br />screened interval extends above static groundwater. The fourth well will be constructed <br />with approximately 5 feet of screened interval in one of the deeper water bearing zones and <br />will be installed to assess the vertical extent of petroleum hydrocarbon impact in <br />groundwater. The location and screened interval for the deep well will be selected based <br />on the findings of the CPT/direct-push boring program. <br />Following installation, the wells will be developed by surging over the length of the screen <br />interval and by purging approximately 10 casing volumes of water. The wells will be <br />developed until the pH, electrical conductivity, and temperature have stabilized and <br />relatively turbid -free water is obtained. <br />There are currently three groundwater monitoring wells at the site (MW -1, MW -2, and MW - <br />3), but the screened intervals of these wells have been submerged since 1996, shortly after <br />their installation. SECOR will not destroy these wells at present because they might aid in <br />assessing the vertical and lateral extent of petroleum hydrocarbon impact at the site. <br />SENSITIVE RECEPTOR SURVEY <br />A sensitive receptor survey will be performed to identify domestic and municipal wells within <br />the vicinity of the site. The sensitive receptor survey will consist of reviewing DWR files and <br />performing a door-to-door field reconnaissance within a one-half mile radius of the site. <br />The locations of all wells identified during the survey will be presented in a figure and <br />summarized in a table in the final report of findings. <br />Department of Water Resources Well Database Review <br />A DWR database review will be performed by SECOR to identify known permitted well <br />locations within a one-half mile radius of the site. The DWR water well drillers reports will <br />be used to identify these wells. <br />Door to Door Well Survey <br />SECOR personnel will also conduct a door-to-door survey of businesses and residences <br />within in a one-half mile radius of the site to determine the location of wells not identified <br />through the DWR database review. If the property owner or resident is not present at the <br />N: \F i les\P rojects\C h evron\Reta i I\#9-2033\REPORTS\2005Add n' IAssessmentW orkPla n, d oc <br />