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Piezometer Construction Details Piezometer Boring Piezometer Screened Sand Bentonite Grout Depth to De th Depth Interval Groundwater* MP-6 41.5 41.0 36 to 41 15 to 36 10 to 15 0 to 10 21 MP-10 60.0 49.0 49 to 44 15 to 44 10 to 15 0 to 10 25 MP-11 43.0 36.2 31.2 to 36.2 15 to 43 10 to 15 0 to 10 25 LH-3 26.0 22.0 17 to 22 15 to 26 10 to 15 0 to 10 Dry LH-6 30.7 27.1 22.1 to 27.1 15 to 30.7 10 to 15 0 to 10 13 LH-9 30.9 22.6 17.6 to 22.6 15 to 30.9 10 to 15 0 to 10 12 j MQ-7A 40.8 39.1 34.1 to 39.1 15 to 40.8 j 10 to 15 0 to 10 Dry * Depth to groundwater noted during piezometer installation PROPOSED SERVICES Task 1 — Pre-Field Activities Kleinfelder will obtain boring/well permits from the Sacramento County Environmental Management Department (EMD) and the San Joaquin County Environmental Health Department (EHD). Additionally, Kleinfelder will arrange, schedule, and observe the subcontractors needed to accomplish the well abandonment process. Underground Service Alert (USA) will be contacted at least 48 hours prior to conducting any on site excavation to locate utilities that may encroach onto the project site. Task 2 —Abandonment of Seven Piezometers In accordance with the Sacramento County EMD and San Joaquin County EHD Well Standards the wells are required to be abandoned properly. Prior to grouting, each piezometer will be sounded to determine its total depth. Each well will be drilled out with eight-inch (outer diameter) hollow stem augers to approximately 1-foot below the total depth of the casing. The borehole will be backfilled with a neat cement mixture to approximately 1-foot below the existing site grade via tremmie pipe. The top five feet of the borehole will be at least one foot diameter greater than the abandonment borehole for the purpose of creating a grout cap. Upon review of the piezometer construction details, the San Joaquin County EHD may permit the four piezometers located in San Joaquin County to be destroyed by pressure grouting. If so, grout will be pumped directly into the existing casing under pressure. The top 3 feet of the ground surface will be excavated to a diameter approximately 1- foot greater than the existing boring to allow for additional grout to form a protective cap over the boring. Kleinfelder anticipates that this method will significantly reduce the proposed costs associated with the drilling subcontractor as detailed in the attached cost estimate. 02001 PROP.ENV/ST07P230/FB:ly Paoe 2 of 5 ©2007 Kleinfelder September 11, 2007