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KLEINFELDER • part-time construction observation of the vegetative layer, and • preparation of the Final CQA report and certification of the barrier layer construction. The SJDPW will serve as the Engineer of Record for site closure and grade control for the final cover. Kleinfelder will act as construction monitor for meeting the requirements of Section 17774, Title 14. The specific testing, monitoring and documentation procedures are called out in appropriate sections which follow. 2.2 REGULATORY REQUIREMENTS Both the CIWMB and the RWQCB regulate landfill capping activities. Title 14, Chapter 3 of the California Code of Regulations is used by the CIWMB. Title 23, Chapter 15 of the California Code of Regulations is used by the RWQCB. Appendix A contains copies of both sets of regulations. 2.3 BORROW OPERATION The excavation of borrow materials will be performed by a qualified earthwork contractor. During excavation of materials soils with SC, CL, CH, ML and SM will be stockpiled for mixing and use in the barrier layer. Care will be exercised whenever clean sandy materials (SP) are encountered. These SP materials will not be used in barrier construction and will be stockpiled for other use elsewhere. 2.4 BARRIER LAYER SOIL DESIGN MIX A total of eight bulk samples were obtained from the two designated borrow areas; the existing Harney Lane site and the North County landfill. At the North County landfill site, two samples were taken around the existing stockpile located in the southern portion of the site. The soil samples collected at the stockpile were both very silty sand. A sample of clean fine sand was obtained directly from the current excavation at the North County site. At the existing Harney Lane site, samples were collected at the base of the existing borrow area south of the present landfill. These samples varied from silty sand to sandy clayey silt. While previous studies indicated that some of the untreated native materials would meet the minimum permeability requirements, it is evident that the majority of the materials currently at the two proposed borrow sites will consist of a more granular soil. Based on our experience over the past seven years, the most cost-effective large supplier of imported clay has been North American Refractories located in Ione. Permeability, gradation and Atterberg Limits tests were performed on samples composed of various percentages of this clay mixed with the eight bulk samples from the two borrow areas. Shown on Table 2-1 is a summary of these laboratory tests. As noted, the percent of Ione clay varied from 15 to 20 percent. During the preparation of test samples, it was intended that the minimum degree of compaction would vary from approximately 90 to 95 percent. The actual degree of compaction varied from 90 to 100 percent based on 3 laboratory compaction curves. On past GSM.md 3EI94 Page 6 of 24 Copyright 1994 Kleinfelder,Inc. Ank