ARCHIVED REPORTS_1988 - Laserfiche WebLink

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III . DETECTION MONITORING SYSTEM A detection monitoring program for the North County Sanitary Landfill has been designed to meet requirements outlined in Section 2556, Article 5 of Subchapter 15 and corresponding applicable federal regu- lations. The purpose of the system is to detect the presence of waste constituents in the ground-water downgradient of burial cells. The program consists of the following components:_ • A network of ground-water monitoring wells • A ground-water sampling and analysis plan • Procedures for analyzing monitoring data Due to the naturally low permeability of site soils and the signifi- cant depth to ground water (see Section II and Table 2) , no liners are proposed as part of the landfill design. The following factors indi- cate that existing conditions will protect the ground water in the unlikely event that leachate is produced: • Low average annual rainfall of 16.27 inches • Low-permeability (I x 10-6 to I x 10-8 cm/sec) clay/silt deposits in the unsaturated zone underlying the site • Depth to ground water, which is historically greater than 40 to 50 feet and currently greater than 125 feet • Availability of on-site, low-permeability soils for use in construction of final cover that conforms with Sub- chapter 15 requirements (Section 2581(a)) • Existence of very good quality ground water underlying the site with no signs of existing contamination from surface activities. The ability of subsurface soils to protect ground water is also supported by the results of the ground-water solid waste assessment test (SWAT) con- ducted at the existing Harney Lane Sanitary Landfill (approximately 2 miles away) , which indicated no adverse effects on the underlying ground water as a result of landfill operations. • Lack of nearby, permanent surface-water bodies PJ9 9390207.00D 9