A. Drainage Plan: The final grading and drainage plan for the subdivision shall be submitted to and approved by the director of public works. The grading and drainage plan shall, as much as possible, be laid out to conform to the natural contour of the land. Storm sewers shall be designed to carry a minimum of the 5-year, as developed, storm and the director of public works may require holding the 100-year storm and releasing water at the 5-year, predeveloped, rate.
B. Design Methodology: The final grading and drainage plan shall be made prior to all other utility plans. The drainage system shall take into account the ultimate development of the tributary area. Surface water drainage plans shall be shown for each and every lot and block on the final drainage plan. (Ord. 2403, 5-21-2012)
C. Drainage Easements:
1. Where topography or other conditions are such as to make impractical the inclusion of drainage facilities within street rights of way, perpetual, unobstructed drainage easements of a minor nature, at least twenty feet (20') in width shall be provided where deemed necessary by the director of public works. The director of public works may require additional width or setback as deemed necessary. Said easements shall be required to be kept clear by the owner from all fill, debris, trees, landscaping, structures or vegetation which will in any way impair the drainage course or the water carrying capacity of the drainageway except that lawn grass which shall be regularly mowed and annual vegetation may be grown thereon. All routine maintenance along said drainageways shall be performed by the adjacent property owners. All such drainageway easements shall be indicated on the plat.
2. Where runoff from the proposed subdivision is redirected or significantly increased, and off premises drainage easements and improvements are required to carry this water away from the subdivision, appropriate drainage rights must be secured and shown on the plat.
D. Additional Information: The director of public works may require whatever additional engineering information he deems necessary on subdivision and other developments which are in areas of questionable drainage.
E. Limitations Of Building Type: The director of public works may limit development in areas with high water tables to structures constructed without basements.
F. Structural Entrances: In areas where drainageways are allowed, all structural entrances shall have an elevation which exceeds the water elevation that would be reached during a 100-year rainfall. (2005 Code)