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Taj M. Bahadori -2- 25 January 2016 <br /> San Joaquin County DPW <br /> Stockton <br /> The following variances were approved by the project design engineer (Geosyntec) and <br /> implemented to address issues encountered during project construction: <br /> • LCRS Gravel - Pea gravel was substituted for rounded/subrounded gravel in the LCRS layer <br /> and LCRS sump after it was determined that no local source of rounded/subrounded gravel <br /> meeting project specifications was available. To demonstrate the acceptability of this change, <br /> a compositely-lined test pad was constructed and the LCRS gravel layer track-walked with a <br /> low ground pressure dozer. No damage to the underlying HDPE geomembrane was observed <br /> after the test. <br /> • Earthworks -The maximum particle size for the lower foot of operations soil was increased <br /> from 3/8 inches to 1 inch to facilitate mechanical screening. The maximum clump size of <br /> foundation soil was increased from 1 inch to 2 inches for similar reasons. <br /> • Shear Testing - Post-peak shear strengths for the foundation layer/GCL interface at normal <br /> stresses at or above 6,000 psi did not meet project specifications. Follow-up sandwich testing <br /> showed that the foundation layer/GCL interface was not the critical interface, however, such <br /> that the nonconforming shear strengths were acceptable. Nonconforming side slope shear <br /> strengths measured for the geocomposite/HDPE geomembrane interface were also found to be <br /> acceptable after performing additional slope stability analysis. <br /> • Piping -A spare leachate force main was installed and routed to the leachate tank farm to <br /> provide additional leachate handling capacity. <br /> The Final CQA Report includes a certification that Module 2, Phase A was constructed in <br /> accordance with the approved construction drawings, specifications, and CQA plan, and in <br /> conformance with Title 27 and Subtitle D requirements. Based on this certification and the <br /> information in the report, including design modifications, the Final CQA Report for Module 2, <br /> Phase A is hereby approved. The module may now be operated on a long term basis. <br /> If you have any questions, please contact me by telephone at (916) 464-4641 or by email at <br /> iohn.moody .a?_waterboards.ca.gov. <br /> John Moody, P.E. <br /> Water Resource Control Engineer <br /> Title 27 Permitting and Mines <br /> Enclosure <br /> cc: Christine Karl, Permitting & LEA Support, CalRecycle, Sacramento <br /> Robert McClellon, San Joaquin County Environmental Health Department, <br /> Stockton <br /> Krzysztof Jesionek, Geosyntec Consultants, Inc., Walnut Creek <br /> Michael Raub, Advanced Earth Sciences, Inc., Irvine <br />