(A) At a minimum, new development and redevelopment as described in section 9-9-5 shall not result in a net increase in peak flow leaving the site from pre-development conditions for the one-year, five-year and ten-year, six-hour storm events.
(B) New development and redevelopment, as described in section 9-9-5, in areas at special risk with well-documented water quantity problems as determined by the Stormwater Administrator, shall not result in a net increase in peak flow leaving the site from pre-development conditions for the 25-year, six-hour storm event.
(C) Peak flow leaving the site from pre-development conditions for the one-year, five-year, ten-year and 25-year, six-hour storm events shall be calculated, and the plan shall be prepared and approved using the standards of the City Engineer, as set forth in the city's Manual of Standard Designs and Details and stormwater management program.
(D) The drainage plan as required by this section shall include but not be limited to a site plan showing existing proposed buildings, storm drainage facilities, ground cover, site construction plans with grading plan, and drainage system; drainage facility design data including area map, engineering calculations, area of impervious cover and total land area.
(E) In the event that literal interpretation of this section creates an undue hardship, the applicant may appeal to the Board of Adjustment for a variance in whole or in part from this section.
(F) No part of this section shall be applied to structures existing prior to the effective date of this section nor shall existing impervious ground cover be used in the calculation of runoff.
(G) New development and redevelopment, as described in section 9-9-5 is deemed compliant with the requirements of this section when meeting the conditions of an approved public/private partnership development agreement subject to G.S. 160D-1001.
(Ord. No. 24-021, § 1, passed 4-11-2024)