§ 16-68 CLASSIFICATION OF DRAINAGE CHANNELS.
   (A)   For the purposes of these regulations drainage shall be classified as follows:
      (1)   Surface drainage is runoff of a limited quantity and/or slow rate that it does not cause erosion of a defined channel;
      (2)   A minor tributary is any drainage channel having a drainage basin of 640 acres (one square mile) or less in area;
      (3)   A major tributary is any channel having a drainage basin of not less than one square mile or greater than 25 square miles; and/or
      (4)   A river is any channel having a drainage basin of greater than 25 square miles.
   (B)   It is intended that responsibility for drainage be allocated as follows, unless otherwise specifically designated;
      (1)   The developer is responsible for the following:
         (a)   All surface drainage on the subdivision or planned unit development;
         (b)   All increases in surface drainage outside the subdivision which results from the development of the subdivision;
         (c)   The improvement of all minor tributaries lying within the subdivision or planned unit development;
         (d)   Any significant increase in rate or quantity of runoff in any minor or major tributary or river which results from the development of the subdivision; and/or
         (e)   Provision for the maintenance of all floodway and flood-fringe areas of major tributaries and rivers which have not been dedicated to the public.
      (2)   The city and other levels of government will be responsible for the following:
         (a)   The improvement of floodways of major tributaries;
         (b)   The improvement of river floodways; and/or
         (c)   The maintenance of floodway and flood-fringe areas dedicated to the public.
(`90 Code, § 16-14)