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V cl-ITOR <br />0 EJN!GflVEERflVG, INC. <br />September 18, 2008 <br />Job No. 021605.08 <br />Mr. Lochlin Caffey <br />Forward Landfill, Inc. <br />9999 Austin Road <br />Manteca, California <br />Re: Geoelectric Leak Detection Surveys - Forward Landfill FU -08 <br />Dear Lochin Caffey, <br />This report documents the geoelectric leak detection surveys conducted by Vector <br />Engineering Inc on the primary liner of the FU -08 expansion at the Forward Landfill. <br />Vector conducted the first survey on the exposed geomembrane from August 25 to August <br />27, 2008. After placement of the soil operations layer, the second survey was performed <br />from September 16 to September 17, 2008. The area surveyed was approximately 13.5 <br />acres. This report describes the methods, procedures, calibrations and results of the two <br />surveys. <br />AMk <br />Water Lance Method for Exposed Geomembrane <br />Method / Procedure <br />The method used to perform the geoelectric leak detection survey on the exposed <br />geomembrane was the water lance method. Testing was performed in accordance with <br />ASTM D7002-03. The water lance leak detection technique consists of the application of a <br />difference in electrical potential between the surface under the geomembrane and a water <br />jet sprayed onto the surface. Geomembranes prevent the flow of electrical current. In the <br />event a leak is present, the water becomes in contact with surface below the <br />geomembrane and thus allowing the flow of electrical current. A current detector informs <br />the operator via visual and audio signals of the presence of a potential leak. The leak is <br />localized and identified by the operator and documented on the daily report. <br />In addition to identifying leaks in the geomembrane, the operator will identify any <br />irregularities in the subgrade that may affect the geomembrane. These irregularities are <br />not leaks, however they are identified for the installer and CQA personnel to evaluate and <br />repair, if necessary. <br />Calibration <br />The equipment was calibrated by making a 1 mm hole in the geomembrane and adjusting <br />the sensitivity of the leak detection equipment to detect the hole when passed over it. This <br />procedure was conducted each day prior to beginning work. In addition, the equipment <br />® 143E Spring Hill Drive • Grass Valley, California 95945 • (530) 272-2448 • Fax: (530) 272-8533 <br />USA 0 CEN"IRAL & SOUTH AMERICA 0 PHILIPPPfES <br />