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2.3 Utility Clearance Prior to any drilling activities, GHD will mark out the proposed boring locations with white paint and notify Underground Service Alert (USA) of the proposed drilling locations a minimum of 72 hours prior to drilling. All boring locations will be hand cleared to a depth of five feet below ground (fbg) prior to drilling. 2.4 Soil Borings, Grab Groundwater Sampling and Analysis GHD will advance four borings and collect a grab groundwater sample from each boring (Figure 1). Each boring will be drilled to a depth of 20 fbg, or 10 feet below first encountered groundwater, depending on Site conditions. A temporary PVC well casing and 10 feet of screen will be inserted into each borehole prior to sample collection. Grab groundwater samples will be collected using a peristaltic pump, clean stainless steel bailer, or new disposable bailer, and field filtered using a 0.45 micron filter. Field filtering kits and sample containers will be provided by a California certified laboratory. Following sample collection, groundwater samples will be stored in an ice-chilled cooler and transported under chain-of-custody (COC) documentation to a California certified laboratory where they will be analyzed for dissolved arsenic by EPA Method 200.8 2.5 Investigation Derived Waste All investigation derived waste will be temporarily stored onsite in labeled DOT approved 55-gallon drums pending offsite disposal at an approved disposal facility. 2.6 Reporting Following completion of field activities and receipt of the analytical results, GHD will prepare a report that will include: Description of the soil boring and grab groundwater sampling activities, Tabulated groundwater results, Figure depicting grab groundwater boring locations, Laboratory reports and COC forms, An evaluation of the analytical results, which may include a statistical evaluation of arsenic concentrations in groundwater Conclusions and recommendations. 080238-RWOCB-03-GW Inv WP Memo.docx 2