Drainage facilities shall be provided for subdivisions, partitions, replats, or planned unit developments, and shall be connected directly to existing drainageways or storm sewers outside of the proposed land division that have an adequate capacity to accept drainage water from the subdivision, partition, replat, or planned unit development as provided below:
A. Design of drainage within the subdivision, partition, replat, or planned unit development shall be approved by the County Engineer, consistent with the County's master storm drainage plan, and shall take into account the capacity and grade necessary to maintain unrestricted flow from areas draining through the subdivision, partition, replat, or planned unit development, and to allow extension of the system outside the subdivision, partition, replat, or planned unit development;
B. Drainage for the individual lots of the proposed subdivision, partition, replat, or planned unit development, and the proposed subdivision, partition, replat or planned unit development as a whole, shall be accomplished in such a manner so as to prevent the excessive flow of water across property lines, sidewalks, and other public rights-of-way;
C. When in the opinion of the County Engineer, land in a subdivision, partition, replat, or planned unit development which is or will be periodically subject to accumulations of surface water or is traversed by any watercourse, channel, stream, or creek, shall be required as a condition of approval to provide for adequate unrestricted drainage by the developer;
D. Provision for drainage shall be shown on a drainage plan both within and adjacent to the subdivision, partition, replat, or planned unit development. The plan shall show all easements and any improvements to be constructed;
E. Public improvements shall be approved by the Review Body as adequate for the drainage needs of the area. Where necessary, for protection of any needs, the Review Body may condition the tentative plan approval on the conveying of ownership of a drainage easement for drainage purposes to the County.
(2005 RLDC § 83.050)