Drainage rules for subdivisions

A. Drainage systems in all subdivisions shall be planned, designed, and constructed in accordance with standards of the department or consistent with generally accepted engineering practices certified by an engineer so as to meet the following: 1. Protect and preserve existing natural drainage ways to the extent feasible; 2. Design a drainage system to be compatible with surrounding conditions; 3. Provide a system by which water within the subdivision will be removed using the natural drainage area where feasible with a minimum disruption to existing drainage patterns and without causing unnecessary harm to adjoining areas; 4. Analyze drainage requirements for each subdivision individually and take every means to insure the ability to subdivide the land within its zoning; 5. Assure that waters are drained from the subdivision in such a manner that they will not cause erosion outside of the subdivision to any greater extent than would occur in the absence of subdivision and improvements thereto; and 6. Provide for the crossing of watercourses by culverts rather than spanning where possible. B. Where interior drainage systems within an area are improved, a storm drainage system shall be required in all subdivisions within that area where surface runoff cannot be adequately conveyed. Where open channels are used, the subdivider shall provide total right-of-way, including a ten foot wide maintenance road along both banks where the top channel width exceeds fifty feet, and along one bank where the top width is fifty feet or less. The director may require that maintenance roads along the channel shall be topped with six inches of crushed coral or base course and treated with bituminous material. In lieu of a maintenance road, for normally dry channels, access ramps, or other suitable alternative measures to facilitate maintenance may be provided. Underground systems shall have a minimum easement width of fifteen feet. (Ord. No. 4053, § 44, 2013; Ord. 789 § 1 (part), 1974: prior code § 11-1.10(o))