Street Design Manual

Article 12.4 Drainage, Curb, and Gutter Design 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. Section 12.4.1 Curb Installation requirements 1. Standard curb and gutter can be used on all streets. 2. Granite curb shall be required when it previously existed or a streetscape plan recommends the use. 3. Valley-type curbs are permitted for Neighborhood Yield and Neighborhood Local, if all the following are met: a) Where any existing street containing a standard curb and gutter is to be extended, the curb and gutter shall be extended to at least the next intersection. b) Curb treatments shall be the same on both sides of a street, but a different treatment may be used adjoining a median. c) At the interface of differing curb or shoulder treatments, drainage structures are to be installed to assure uninterrupted flow of storm water between the two drainage systems. 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.

A. Curb and gutter is not required on the following streets:

a) Sensitive area thoroughfares or roadways located within a Reservoir Watershed Protection Area Overlay District. Curb and gutter may be required where right-of-way is restricted or where needed to control stormwater erosion and sedimentation. b) Roadways other than thoroughfare system roadways that were inside the City limits and paved prior to 1950. c) Where curb and gutter is not planned to be installed in the future as part of design plans on street improvements, or where none is required as part of a City Council approved Neighborhood Plan.

B. Alternative curb systems, such as no-elevation curb, curb openings, flat curb, and other alternative systems, may be allowed in place of standard curb and gutter systems as described in Section 12.4.1, subject to:

Raleigh Street Design Manual – Page 96