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• 3.4.2 SURVEY/SETTLEMENT MONUMENTATION In order to monitor the future settlement of the landfill, settlement and survey monuments will be installed on the landfill in accordance with 27 CCR, Section 20950 (d). These monuments are proposed to consist of galvanized pipe, two inches in diameter and six inches in length placed in blocks of concrete, 24- inches in diameter by eight inches in depth. A nail and tag will be placed in the center of each monument for identification (see Detail 9 on Drawing 1 of the JTD). Four settlement monuments are proposed to be placed on the landfill area as shown on Drawing 4 of the JTD. Survey monuments will be placed on undisturbed ground as reference points not subject to settlement as shown on Drawing 4 of the JTD. These points are the horizontal and vertical control points for the site aerial topographic survey and will be maintained or replaced, as needed, throughout the post-closure maintenance period. An aerial photographic survey of the site with a maximum contour interval of two feet will be performed and provided to the RWQCB, LEA and the CIWMB upon • completion of closure activities. The settlement monuments will be surveyed upon completion of all closure construction activities. Additionally, in accordance with 27 CCR requirements, Forward will update the aerial survey of the entire refuse footprint every five years throughout the post-closure maintenance period. Included as part of the survey information, an iso- settlement map and report is to be submitted to the RWQCB. 3.5 LANDFILL SLOPE STABILITY A slope stability analysis is required by 27 CCR, Section 21090 when the closure design includes final slope faces steeper than 3:1 (horizontal to vertical) or a synthetic component in the final cover configuration. The proposed final slopes for the Forward Landfill do not exceed 3:1 but, the final cover design includes a barrier layer which consists of a synthetic component (e.g., VFPE). Therefore, a slope stability analysis was conducted pursuant to 27 CCR, Section 21750(f)(5) to review the integrity of final slopes under both static and dynamic conditions. The results of the slope stability analysis are included in Appendix E of the JTD. • The slope stability analyses anticipated that the cover system could be constructed using a combination of compacted clay, geocomposite clay liner Forward Landfill PCPCMP 3-7 L:\Allied\2000.193\Reports\FinaIPCPCMP:FL-sec3.doc:5/21/02 BRYAN A.STIRRAT 6 ASSOCIATES