(A) All development shall be required to apply for and obtain a stormwater permit addressing the below, except that listed as a driveway permit shall be covered under that permit and not the stormwater permit.
(1) Driveways. Stormwater runoff from driveways, residential or commercial, shall not discharge directly onto public or private thoroughfares. Runoff shall be diverted to stormwater drainage facilities such as drainage ditches, stormwater systems or on-site intrusion systems. On streets with a curb and gutter section, runoff from a driveway directly to the curb and gutter is anticipated and allowable; provided however, the driveway shall not be steeper than a 3% to 4% grade. For streets with roadside ditches, the driveways shall be cross-sloped or crowned to direct the runoff to the ditch system before the driveway connection to the street. A trench drain may also be used to intercept the runoff before it enters the street. Driveway permit item.
(2) Driveway access. Residential driveway access shall be a maximum of 36 feet wide. Note: this may be split up to allow for two 18-foot driveway access points where the lot size will permit. In any case, the driveways or culvert piping shall not be located any closer than five feet from the side property line. Driveway permit item.
(3) Lot plans. Applicants shall prepare a site plan for each and every lot to be developed that accounts for street flooding and local drainage from and onto adjoining properties. The applicant shall be responsible for protecting the development/building from such local drainage flow and shall discharge the drainage flow onto adjoining lots in a manner that does not adversely impact the adjoining lots, in each and every case providing for a point of collection on the applicant's lot prior to discharge onto an adjoining lot that does not create a hazard or exacerbated drainage problem on adjoining lots.
(4) Impervious surface limits. No lot shall exceed 50% impervious surface without managing stormwater. Such stormwater management shall limit the post-development runoff discharge of the impervious surface area exceeding 50% of the lot to a rate no more than the pre-development 25-year, 24-hour storm runoff discharge rate. The maximum amount of impervious surface permitted on any lot shall be 90%.
(a) Lots that fall outside of a master stormwater permit or otherwise not part of a stormwater management plan approved by the State of North Carolina shall limit the post-development runoff discharge of any impervious surface area to a rate no more than the pre-development 25-year, 24-hour storm runoff discharge rate.
(5) Elevation. The finished floor elevation of the first floor of any structure, including the garage, must be a minimum of 18 inches above the surrounding finished grade or the crown of the roadway, whichever is greater.
(6) Easements. Easements shall be restricted to prohibit all fences and structures which would prevent access to the easement areas and/or prevent the maintenance of the drainage system.
(7) Downspouts. No downspouts from roof gutters shall be discharged into town ditches, or onto public or private driveways, parking areas and other impervious surfaces that drain directly to storm sewers or streams. All such downspouts from roof gutters shall be discharged into stabilized vegetated areas where the runoff can infiltrate or by other means that allows the runoff to infiltrate the ground as may be approved by the UDO Administrator.
(B) If a new development has a disturbance of one acre or more, or, proposes to construct more than 10,000 square feet of built-upon area, all stormwater control designs shall limit the post-development runoff discharge rate to no more than the pre-development 50-year, 24-hour storm runoff discharge rate. The developer shall comply with all applicable requirements and thresholds established by the State Department of Environmental and Natural Resources (Division of Water Quality, Division of Coastal Management (CAMA), and Division of Land Quality), and the U.S. Army Corps of Engineers. A separate master stormwater permit shall be issued pursuant to this section only upon receipt of a completed application including permits from all other regulatory agencies in addition to engineered plans and specifications in compliance with the design limitations set forth herein. The issuance of a master permit under this section shall not preclude or supersede permitting as required in division (A).
(Ord. eff. 9-6-2012, § 10.23; Am. Ord. 19-2, passed 7-12-2018; Am. Ord. 21-1, passed 9-17-2020)