(A) (1) The Planning Commission shall not recommend acceptance of any plat unless, after consultation with the Municipal Engineer, they determine that the proposed provisions for stormwater drainage are adequate. Drainage improvements in the subdivision or development shall be coordinated with existing and planned drainage improvements elsewhere so as to form an integrated municipal system.
(2) The stormwater drainage system shall be separate and independent of the sanitary sewer system. The storm drainage facilities shall comply with the requirements indicated in the minimum design standards.
(B) Manholes, inlets, and catch basins, if required, shall be constructed to comply with the requirements in the minimum design standards, so that surface water is not carried across or around any intersection, or for a distance of more than 600 feet in the gutter.
(C) A culvert or other drainage facility large enough to accommodate potential runoff from the entire drainage area upstream from the proposed subdivision or development shall be provided in accordance with the minimum design standards. Potential runoff shall be determined on the basis of the maximum development of the upstream area that is permitted under the zoning district regulations.
(D) The subdivider/developer and Municipal Engineer shall give due consideration of the effect of any proposed subdivision or development on downstream areas. Where it is anticipated that additional runoff or increased rate of runoff incident to construction of the subdivision or development will overload an existing downstream drainage facility, the municipality shall require the subdivider/developer to install additional drainage improvements to alleviate the overload problem and/or stormwater management facilities require the minimum design standards.
(E) (1) It is the policy of the municipality to discourage and/or prohibit subdivisions and developments in areas subject to flooding, including during 100-year storm recurrence interval.
(2) Whenever a plat is submitted for an area that is subject to flooding, the municipality shall require appropriate protective measures, which measures shall meet the requirements of the State Department of Transportation, Division of Water Resources and Corps of Engineers, and other jurisdictional agencies.
(F) (1) Adequate easements for stormwater drainage shall be established along any natural or new drainage channel in any other locations where necessary to provide satisfactory disposal of stormwater from streets, alleys, and all other portions of the subdivision or development. The precise location and minimum widths of said easements shall be reviewed and accepted by the Municipal Engineer.
(2) The owner of the lot or tract where drainage easements are located shall be responsible for continuing and proper maintenance of the drainage way within the limits of the easement. This requirement shall be clearly indicated on the final plat as a covenant for acceptance of the subdivision or development by the municipality.
(1978 Code, § 16.28.050) (Ord. 96-11, passed - -1996)