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Proposal for Groundwater Testing Preston Pipelines-Delta Water Intake Project January 12,2010 Page 2 of 3 Grab Groundwater Sampling Activities: One direct push boring will be advanced to collect groundwater"grab" samples at the most shallow but,yet, groundwater yield depth. By using collecting the water from the shallow undeveloped boring hole, we are attempting to have a sample that will be as representative as possible of groundwater encountered during construction. The groundwater grab samples will be analyzed to assess all parameters identified in the screening requirements of Order No. R5-2008-0082 and the 303d (East Delta Waterways — Central Portion) TMDL list. Samples will be analyzed for the same constituents analyzed during the recent sampling activities at King Island and Empire Tract in April 2009. The boring will be advanced using a direct push rig. The outer barrel for advancing the direct push soil borings will be approximately 2 inches in diameter, and the inner barrel will be approximately 1.75 inches in diameter. The dual-wall system minimizes sloughing, maintains boring alignment and minimizes vertical migration of contaminated soils or fluids. Grab groundwater samples will be collected from a depth of approximately 25 feet below ground surface (bgs) or at the most shallow groundwater yielding depth. Once the sampling depth is reached, the sampler barrel and rods will be removed and 0.75" or 1" PVC casing will be inserted into the boring. Prior to insertion, the PVC casing will be assembled so that the bottom five feet of the boring is inserted with 0.002" slotted casing. A grab groundwater sample will then be collected from inside the casing using a disposable bailer or a peristaltic pump. Approximately 30 gallons of groundwater will be collected for laboratory analytical and whole effluent toxicity(WET) testing purposes. After sampling is complete, the boring will be backfilled using hydrated bentonite from the boring bottom to approximately 1 foot bgs. The remainder will be capped with soil to match the existing surface. The location of the boring will be hand drawn onto a site map using topographical references and measurements. Unless specifically requested, the location of the boring will not be surveyed by a California licensed land surveyor. Sample Handling: All groundwater samples will be labeled with all pertinent sampling information, and packed on ice for subsequent delivery to a California state-certified laboratory for analyses. Sampling equipment will be decontaminated before and, if necessary, during sampling episodes using a triple rinse method consisting of a wash with Alconox (or equivalent) solution, an initial rinse with tap water, and a final rinse with de-ionized water. Samples will be placed in an ice-filled cooler and transported to their assigned California- certified laboratory under appropriate chain-of-custody documentation. Sample Analyses: The grab groundwater samples associated with standard analytical testing will be submitted to and analyzed by McCampbell Analytical (ELAP #1644) in Pittsburgh, California. The samples testing for the pesticides Diazinon and Chlorpyrifos, as well as Pyrethroids, will be shipped to and analyzed by CRG Marine Labs (FLAP #2261) in Torrance, California. Groundwater samples needed for Toxicity Testing will be transported to Sierra Foothill Laboratories (ELAP#1113) in Jackson, California.