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HomeMy Public PortalAboutSec 3-080C5 6.10.2014 PROPOSED ORDINANCE06/10/2014 PROPOSED ORDINANCE Sec. 3-080. Off-street parking requirements. (C)(5) For water quality purposes, all newly constructed driveways and replacements of more than 50 percent of existing driveways serving residential uses shall be constructed of materials designed to allow retention of the first one-inch of stormwater. A new driveway includes the initial placement of any material on bare soil. Such new driveways and replacements of more than 50% of an existing driveway are subject to permitting and inspection(s). A permit and inspection(s) are also required for repair of less than 50% of an improved driveway. The retention requirement is based on a 24-hour, 25-year Type III SCS storm. A permit is required for installation of a new or replacement driveway. An inspection is required of each layer prior to the next layer being installed. The permit applicant shall be responsible for all engineering fees incurred by the city for review of materials, even when a material is not approved. Acceptable materials include: a. Stone must be either AASHTO #57, #67, #78, or #89 open-graded with no fines, or pea gravel with no fines, or a combination of two or more. Graded aggregate base (also known as “crusher run” or “crush and run”) is not allowed. b. Standard brick pavers are 4-inch by 8-inch with minimum 5/64-inch average continuous joints/borders with eight 1/8-inch wide spacers per paver filled with masonry sand. See item (c) for base and header requirements. If larger bricks are used, thereby creating less linear joint and surface area joint, calculations by a Georgia licensed design professional must be reviewed and approved by the city. See engineering fee information in paragraph 1. c. Permeable interlocking concrete pavers (PICP) are solid structural units installed with openings as described in the Coastal Stormwater Supplement (CSS) through which stormwater runoff can rapidly pass into the underlying reservoir of a 4-inch minimum depth open-graded stone, no fines. Openings may be filled only with pea gravel or larger stone, or with masonry sand. A concrete header curb or paver/concrete block ribbon with a maximum width of 8-inches must be installed around the perimeter of the pavers. Building foundations and garage floors may serve as a portion of the perimeter. The edge of a paved road may not serve as a perimeter. Flush headers and ribbons are included in the driveway measurements. To not be included in the driveway measurements a header or ribbon must be installed lower than the driveway pavers, covered with adequate top soil, and seeded or sodded to facilitate vegetation. d. Ribbon driveway designs are normally constructed of concrete but other materials may be considered. The ribbons are to be a maximum of 18-inches wide with a 1%-2% cross slope to route runoff to adjacent pervious areas rather than down the strips to the street. The area between the strips may be either grass or stone as described in item (a). The area between the drive strips is to be flush or 1/8-inch below the driving strip to encourage the percolation of stormwater runoff between the driving strips. e. Concrete grid pavers (CGP) are precast concrete units that allow rainfall and stormwater runoff to pass through large openings that are filled with pea gravel, sand or topsoil and turf. A concrete header curb or brick/concrete block ribbon with a maximum width of 12-inches (flush or 1/8-inch higher than the contained permeable pavement) must be installed around the perimeter of the permeable pavement. Building foundations and garage floors may serve as a portion of the perimeter. The edge of a paved road may not serve as a perimeter. Flush headers and ribbons are included in the driveway measurements. To not be included in the driveway measurements a header or ribbon must be installed lower than the driveway pavers, covered with adequate top soil, and seeded or sodded to facilitate vegetation. f. Plastic grid pavers (PGP) consist of flexible, interlocking plastic units that allow rainfall and stormwater runoff to pass through large openings that are filled with gravel, sand or topsoil and turf. A header curb is required and is included in the driveway measurement. g. Pervious concrete (also known as porous concrete) is similar to conventional concrete in structure and form, but consists of a special open-graded surface course, typically 4- to 8-inches thick, that is bound together with portland cement. h. Porous asphalt is similar to pervious concrete, and consists of a special open-graded surface course bound together by asphalt cement. For all other proposed materials, calculations are required from a Georgia licensed design professional demonstrating compliance with the retention requirement of this ordinance.