106. When the height of landfilled construction or demolition waste reaches a level that is 90 cm below the ground surface at the perimeter of a disposal area, the area must receive a final cover consisting of, from the bottom up,
(1) an impermeable soil layer with a constant maximum hydraulic conductivity of 1 x 10-5 cm/s, through a minimum thickness of 45 cm after compaction, or a geomembrane at least 1 mm thick placed on a soil layer at least 30 cm thick having characteristics that preserve the integrity of the geomembrane; and
(2) a barrier soil layer at least 45 cm thick if the above-mentioned impermeable layer is a soil layer, or 60 cm thick if the impermeable layer is a geomembrane. The upper portion of the layer prescribed by this subparagraph must also, to a depth of between 15 and 30 cm, consist of soil or materials suitable for vegetation. The characteristics of the soil or other materials used must be such as to preserve the integrity of the impermeable layer.
In addition, any raising of the ground surface at the perimeter of a disposal area is prohibited.
With the exception of the layer of soil or material suitable for vegetation, the layers referred to in subparagraphs 1 and 2 of the first paragraph may also consist of soils containing contaminants in a concentration equal to or lower than the limit values set out in Schedule I to the Land Protection and Rehabilitation Regulation (chapter Q-2, r. 37). Those limit values do not apply to contaminants that do not originate from human activity. The layers may also consist of other material if the material meets where applicable the requirements of this paragraph and the minimum thickness of the layers is as prescribed in those subparagraphs.
In order to allow the water to flow away from the disposal area and limit soil erosion, the final cover must also be graded
(1) to a slope of 2%, if the slope at the perimeter of the disposal area does not exceed that percentage; or
(2) to a slope that equals the slope percentage at the perimeter of the disposal area, if that perimeter slope is greater than 2%.
Not later than 1 year after installation of the final cover, the final layer must be given a vegetative layer. Damage such as holes, fissures or subsidence that may occur in the final cover must be repaired immediately to prevent water from pooling over or infiltrating into the disposal area, until the disposal area has been fully stabilized.
The provisions of sections 34 to 36 relating to quality assurance and control apply, with the necessary modifications, to the final cover of disposal areas prescribed by this section.
O.C. 451-2005, s. 106; O.C. 451-2011, s. 26.