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On April 8 and 9, 1999, Apex personnel supervised the advancement of eight soil borings at the subject property (Figure 2). The results of all soil and water sampling were documented in the report Results Report for Subsurface Investigation and Second Quarter 1999 Groundwater Monitoring dated June 1, 1999. In accordance with Apex's Workplan of August 6, 1999, Apex personnel supervised the drilling of four soil borings (MW-4A, MW-7, MW-8, and MW-9) on October 19, 1999, at the locations indicated on Figure 2. The results of all soil and water sampling were documented in the report Results Report for Subsurface Investigation and Fourth Quarter 1999 Groundwater Monitoring dated November 30, 1999. The County responded to our November 30, 1999 report in a letter dated March 9, 2000. A copy of the County's March 9, 2000, letter is presented in Appendix A. This Workplan will address all the concerns referenced in this letter. PROPOSED INVESTIGATION Apex proposes to drill four soil borings on and off-site and convert three of the four borings into groundwater monitoring wells MW-10, MW-11 and MW-12, (Figure 3). The remaining soil boring (SB-deep) will be drilled in the area of existing groundwater monitoring well MW-8 to define the vertical extent of petroleum impacted soil in this area (Figure 3). Three of the four proposed soil borings (MW-10, MW-11 and MW-12) will be drilled to an anticipated total depth of 20 feet below grade (bg) with the use of a hollow stem auger drill rig. Proposed soil boring SB-deep will be drilled to an anticipated total depth of 50 feet bg. If an aquitard is encountered below the first shallow aquifer(top of this aquifer is at approximately 10 feet bg) while drilling proposed soil boring SB-deep, Apex will stop drilling and collect a final soil sample from SB- deep. If the final soil sample from SB-deep indicates the presence of petroleum hydrocarbons, Apex may have to install a conductor casing at a later date and continue with the drilling of SB- deep. Soil samples will be collected at five-foot intervals, obvious lithologic changes, or obvious hydrocarbon odors from each of the borings. Soil boring SB-Deep will be continuously sampled to provide a complete a lithologic boring Iog record. All fieldwork will be conducted according to the Apex Standard Operating Procedures (SOP) included in Appendix B. The proposed locations of groundwater monitoring wells MW-10 through MW-12 are to define the lateral extent of petroleum impacted groundwater. The three proposed groundwater monitoring wells will be constructed as two-inch diameter wells and screened set from 5 to 20 feet bg (Figure 4). Off-site right-of-entry or an encroachment permit will be required prior to the drilling of proposed groundwater monitoring well MW-12. Prior to drilling, the underground utility notification network, USA, will be contacted for identification of buried utilities at or entering the project site from the public right-of-way. As a further precaution against drilling into or through potential buried obstructions, the first five feet of the boring will be augured by hand.