No filling or grading shall be permitted which increases flood hazards, water velocities, or flood elevations. Compensatory storage volumes may be required. Armoring protection such as rock riprap or bulkheads shall be constructed to protect filled areas when water velocities exceed two feet per second. All armoring protection shall be elevated at least three feet above the base flood elevation. All construction elevated by piling shall be designed by a professional structural engineer and approved by the City prior to construction. [Ord. 501 § 3, 2009.]