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r�. SCoill E '1'lte scope of this investigation wiil inciude coordinating access approval for installation of the wells, ins[allation of five groundwater[nanitoring w'elis and one ztraunciwater extraction well. coordinLtion of soil and groundwater disposal, and a complete horizontal and vertical survey of :€ll existil,g on-site. weils and proposed off-si[e wells relative to a known local benchmark elevation performed by a registered professional surveyor. - Hvdtocarbons have been identified in the groundwater in all of the existing monitoring wells on the site. Table 1 presents pertinent information on each of the proposed wells/borelioles. %yells ATR-3 through ATR-12 have been proposed in order to more completely define rite snit and groundwater contamination before remediation takes place, as required by the County. Boreholes BH-1 and 13H-2 have been proposed to identify the soil conditions near the underground storage tanks (USTs). one extraction well will be drilled by 8-inch hollow-stem augers and will be continuously cored from the surface to a depth of 20 feet below the water table or pfezometric surface. The borehole will be reamed out to total depth using 12-inch augers and will then be completed as a monitoring well by the method described below. The extraction well will be located near ATR-3 as indicated on Figure 1. Groundwater occurs at approximately 1 I feet below the ground surface at this site and the extraction well is expected to be approximately 40 fee: deep. The immediate purpose of the groundwater extraction well is to provide a means of conducting an aquifer test to determine aquifer characterisdcs (relevant to the final groundwater remediation system design). The extraction well will be used in the final remediation system design. The question of the discharge of the treated groundwater from Lhe extraction well has not yet been addressed- A schemadc of the extraction well construction is shown on Fgure 4. The well screen will be selected based upon a grain size analysis performed by Brown and Caldwell on samples collect:d from the saturated zone of either TEX-I or BH-2. The proposed well design is intended to accommodate water-level iluctuadons and drawdown during extraction within the slotted interval. The p.oposed well' design may be modified in the field during the drilling operation,depending upon conditions encountered during drilling. In no case will i,he monitoring well penetrate r?ay zones greater than feet thick (based on field observations of continuous core), which might allow downward migration of contaminants into lower water-bearing one Blank 6-inch-diameter Schedule 40 PVC casing will extend from the top of the perforated section to the ground surface. �t perforated m will be ttac e�' to the bottter om of the s reen. A bot o p g Schedule 40 PVC. A 5_ P will be-fitted onto the bottom of.this.sump.-._...._ _. The annular space surrounding the well screen and casing will be packed with a filter pack ed from the batted designed to be compatible with the natural formation. The filter will be plac of the sump to approximately 2 feet above the top of the screen. The well will theta be bailed