Entry: Cover systems
URI: https://data.geoscience.earth/ncl/ISO24212/9.17
Cover systems rely on physical passive containment. They are not treatment techniques but engineered based techniques aiming at containing in-situ contamination. They enable: 1) physical isolation of the contaminated ground from the outside environment; 2) control of liquid and gas flows; 3) improvement of mechanical stability; and 4) can be a support for buildings and vegetation. Although covers can consist of a single layer of suitable material preventing site users coming into contact with contamination and dispersal of contaminants by wind and precipitation, they are often multi-functional and comprise a number of layers intended to perform specific functions. For example, to limit or prevent infiltration of water, provide drainage for water and/or gas, prevent upward migration of gas, prevent upward migration of contaminated groundwater, support vegetation, limit rooting depth, support buildings and other structures contain electrical and other services to buildings etc. Each cover system must be designed on a site-specific basis. NOTE 1 There are two types of physical passive containment: vertical barrier technology (see clause 9.16) and surface containment. NOTE 2 The term “capping” is sometimes used but this is best restricted to instances where the primary function is to prevent water ingress, e.g. on old landfills.