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violb Dewberry MEMORANDUM Date : December 8 , 2016 To : Brendan Kenny , Central Valley Regional Water Quality Control Board — R5 From : Neal Williams , Dewberry Subject : Clean Closure Work Plan Comment Response A conference call with Brendan Kenny and Howard Holt of the Central Valley Regional Water Quality Control Board ( RWQCB ) occurred on September 20 , 2016 , with regards to Dewberry ' s Clean Closure Work Plan ( Closure Plan ) . Dewberry prepared the Closure Plan on behalf of the California Department of Corrections and Rehabilitation ( CDCR ) for the closure of the Class II surface impoundments at the Deuel Vocational Institute (the Site) located in Tracy , California . This Closure Plan was prepared to meet the requirements of Provision B . 21 and B . 22 , Class II Surface Impoundment Closures , of the Waste Discharge Requirements (WDR ; 2007 ) , Order No . R5 -2007 - 0005 , issued on January 27 , 2007 to CDCR by the RWQCB — Central Valley Region and Section 21400 ( b ) ( 1 ) of Title 27 , Environmental Protection — Division 2 , Solid Waste of the California Code of Regulations ( CCR ) . During the conference call , there were five recommendations from the RWQCB concerning details in the Closure Plan that either needed clarification or a change . A follow on conference call occurred on October 18 , 2016 in regards to specific information regarding the sampling method for background , characterization , and verification sampling . This memorandum will provide the necessary updates to RWQCB recommendations . Engineered Fill versus Native Soil Sample Collection As detailed in Appendix C — Sampling and Analysis Plan of the Closure Plan , Dewberry initially recommended that soil samples be collected from between 6 and 12 inches below the engineered fill soil surface , or beneath aggregate base or other surficial material if present ( Page 3 , Section 3 . 0 ) . Title 27 requires natural geologic materials underneath the impoundments , if contaminated to be removed . To establish that the underlying native soil is free of contamination , additional sampling will be performed under the approximately 60 inches of engineered fill to reach the native soils . Dewberry amends Appendix C such that in addition to the shallow samples ( between 6 and 12 inches below the engineered fill surface ) , an additional 40 native soil samples will be collected using a drilling crew for boring advancement and sampling ( between 6 and 12 inches below the boundary between engineered fill and native soil interface ) . In addition , as part of this core sampling , an additional 40 engineered fill intermediate soil samples will be collected between 24 to 36 inches for further analysis if the shallow engineered fill is shown to be contaminated . In summary , 120 soil confirmation (40 shallow , 40 intermediate and 40 native ) and 12 native background samples (see Attachment 1 for proposed locations , samples taken between 6 and 12 inches below ground surface ) will be collected . Initially , analytical testing will be performed on 92 of the 132 samples ; the 40 intermediate depth samples will be placed on hold . Sample Analysis As detailed in Appendix C — Sampling and Analysis Plan of the Closure Plan , Dewberry initially recommended that the fill soil beneath the liner system be analyzed for a subset of parameters that are monitored as part of the impoundment monitoring programs specified in the WDR . This subset would include chloride , total dissolved solids , conductivity , calcium , magnesium and sodium ( Page 3 , Section 4 . 1 ) .