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WMU FU -03, WMU F -West Leachate Impoundment and Desilting Basin February 2004 <br />Forward Landfill Job No. 021605.03 <br />0 3.3 Design Modifications <br />n <br />During the construction of WMU FU -03, WMU F -West Leachate Impoundment, and the <br />desalting basin, modifications to the contract drawings and specifications occurred. The <br />approved modifications during construction of WMU FU -03 are as follows: <br />Large Scale Direct Shear results for the geomembrane vs. geotextile <br />interface The large-scale direct shear testing results for the HDPE/geotextile <br />and GCL/HDPE/geocomposite did not satisfy the project specifications. Lewis <br />Engineering (Design Engineer) performed stability analyses using the values <br />obtained from the test and approved the achieved results. A design memorandum <br />approving the achieved results is included in Appendix O. <br />Mass per Unit area of GCL — The conformance test result for a sample of GCL <br />indicated a bentonite mass per unit area of 0.93 lbs/sf at 12.0% moisture <br />content. The specifications required a value of 1.00 lbs/sf at 12% moisture <br />content. The results were forwarded to Lewis Engineering (Design Engineer) for <br />review. Based on the review of the other passing test results for the GCL (i.e. <br />permeability), the mass per unit area of the GCL was accepted by the Design <br />Engineer. <br />■ Anchor Trench Detail — The configuration of the south and west anchor <br />trenches for WMU FU -03 was modified by the Design Engineer to allow for a <br />wider road. This modified detail is included in Appendix O. <br />■ Vent in the WMU F -West Leachate Impoundment — Per the request of the <br />Installer, the spacing of the vents was modified by BAS (Design Engineer) from 5 <br />feet on center as shown on the construction drawings to 50 foot on center. <br />3.4 Final Report <br />Preparation of this final report documenting project CQA activities was the final task of <br />the CQA program for the Forward Landfill, WMU FU -03 composite liner system, <br />desilting basin, and WMU F -West Leachate Impoundment construction project. This <br />report includes discussions of the findings and observations of the on-site CQA <br />personnel regarding the activities identified above. The documentation of construction <br />and CQA activities is presented on the field logs prepared by the CQA personnel, which <br />are included as appendices to this final report. Also presented in the appendices of this <br />Vector Engineering, Inc. • 143E Spring Hill Drive • Grass Valley, CA 95945 • (530) 272-2448 <br />-6- <br />