Street Design Manual

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Reference

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79 Section 11.2.7  Drainage and

Drainage of stormwater runoff away from the streetscape is necessary to retain the function of travel and pedestrian areas as well as for purposes of maintaining integrity of streetscape infrastructure. The location and type(s) of storm drainage features vary by street type; the choice between curb/gutter and shoulder depends primarily on area drainage characteristics (per Article 2.2). Stormwater drainage devices (e.g., pipes, catch basins) are required in streetscapes with curb and gutter treatments. Drainage swales/ditches are typically used to provide drainage in areas where storm sewers are not present, except in secondary Water Supply Watershed Protection Areas. On wider street cross-sections, drainage may occur in medians and/or behind the curb. GSI practices are allowed in the streetscape in accordance with the City’s standard details. Installation of GSI practices must not negatively impact existing street drainage patterns. Curb extension/bump- out and median design must maintain drainage of stormwater and not cause ponding within travel or pedestrian areas. Drainage of stormwater runoff from travel lanes, and parking spaces in the Travelway and from pedestrian sidewalks and other hardened infrastructure in the Streetscape is essential for safe and functional use of these areas. Although drainage is most conventionally accomplished through surface runoff to concentrated conveyances such as curb and gutter systems and then to drainage pipes for ultimate discharge outside of the right-of-way, an alternative means of providing street drainage is the use of non-paved areas for stormwater storage and infiltration using GSI practices. All public roadways inside the corporate limits of the City, and outside the City where water or sewer is connected to the City utility system, shall be constructed with standard curb and gutter or an alternative curb system to accommodate GSI stormwater management . Alternative curb systems include flat curb, standard curb with openings, and other curb systems approved by the Engineering Services Director or a designee. Details for curb and gutter installations can be viewed in the City of Raleigh Standard Details . See Detail T-10.26.1 for standard curb and gutter installation. See Detail T-10-26.2 for alternative curb installation. 4.     Curb openings may be used where drainage conveyance from one side of the curb to another is needed to accommodate the use of GSI practices. E.    Consideration of GSI practices is encouraged in roadway improvement projects.

Green Stormwater Infrastructure

85 Article 12.1

97 Article 12.4 Drainage, Curb, and Gutter Design

97 Section 12.4.1 Curb Installation requirements