When it is determined by the City Engineer that the development of the subdivision will significantly increase runoff in the flood hazard area or will otherwise adversely affect stormwater runoff, the Planning Commission may require any or all of the following to the extent needed to reduce the adverse effects of the development:
A. The existing floodway lying within or immediately adjacent to the subdivision shall be cleaned to provide for the free flow of water, and the channel shall be straightened, widened, and improved to the extent required to prevent overflow beyond the limits of the floodway;
B. Site improvement shall provide for the grading of all building sites and streets to an elevation where all lots, building areas, and streets will not be subject to overflow and in a manner that will provide for the rapid runoff of all rainfall; however, such improvements shall be carried out in a manner that will preserve and protect large trees and attractive physical features of the area;
C. Whenever channel improvement is carried out, sodding, back sloping, cribbing, and other bank protection shall be designed and constructed to control erosion for all the anticipated conditions of flow for the segment of channel involved;
D. A drainage channel shall not be located in a street easement, unless it is placed in an enclosed storm sewer, or unless a paved street surface is provided on both sides of a paved channel to give access to abutting properties; or
E. Culverts, bridges, and other drainage structures shall be constructed in accordance with the specifications of the City at all locations where drainage channels intersect with continuous streets or alleys.
(Code 1991, § 12-501)