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Upon receipt of a site evaluation report from an Applicant, the Director shall determine whether the Prescribed Subsurface Activity Area is subject to the provisions of the California Integrated Waste Management Act (Cal. Public Resources Code § 40000 et seq.) as amended, relating to development on or near a former landfill disposal site. In making this determination, the Director may consult with the Local Enforcement Agency and the California Integrated Waste Management Board.
(a) For any Prescribed Subsurface Activity Area or portion thereof that is subject to such provisions, the Director shall require the Local Enforcement Agency to approve proposed land uses and determine any necessary protective measures or requirements to the extent necessary to comply with California Code of Regulations, Title 27, Chapter 3, Subchapter 4, Article 6 (Section 20917 et seq.) and Subchapter 5 (Section 20950 et seq.), as amended.
(b) For any Prescribed Subsurface Activity Area or portion thereof that is located within 1,000 feet of a former landfill disposal site, but which is not subject to the above- referenced provisions of the California Integrated Waste Management Act, the Director shall review any proposed structures to ensure that the construction or use of the structure will not pose a threat to public health and safety or the environment. In making this determination, the Director shall consider the potential for adverse impacts on public health and safety and the environment, taking into account the following: the amount, nature and age of solid waste in the landfill disposal area; current and projected gas generation; effectiveness of existing controls; proximity of the proposed land uses to landfill disposal area; and other relevant geographic or geologic features. Based on these factors, the Director shall determine whether the structure must be designed and constructed in accordance with the following measures or requirements (or other design providing an equivalent degree of protection against gas migration into the structure): installation of a geomembrane or equivalent system with low permeability to landfill gas between the concrete floor slab of the structure and subgrade; installation of a permeable layer of open graded material of clean aggregate with a minimum thickness of 12 inches between the geomembrane and the subgrade or slab; installation of a geotextile filter to prevent the introduction of fines into the permeable layer; installation of perforated venting pipes, designed to operate without clogging, within the permeable layer; construction of a venting pipe with the ability to be connected to an induced draft exhaust system; installation of automatic methane gas sensors within the permeable gas layer, and inside the structure to trigger an audible alarm when methane gas concentrations are detected; and/or appropriate periodic methane gas monitoring, including monitoring inside structures, with reporting requirements and a contingency and mitigation plan.
For purposes of this section, "structures" shall include: buildings, subsurface vaults, utilities or any other buildings or areas where potential gas buildup would be of concern.
(c) If the Director determines under subsections (a) or (b) of this Section that protective measures or requirements are necessary, the Director shall inform the relevant department in writing that such measures or requirements must become conditions of the permit or improvement plan.
(Added by Ord. 303-04, File No. 041541, App. 12/24/2004; Ord. 204-10, File No. 100575, App. 8/3/2010)