(A) A conditional use must not cause any increase in flood damages, nor any increase in flood elevations in areas where a floodway has been established, as certified by a registered professional engineer.
(B) Fill; Storage of materials and equipment.
(1) Fill, dredge spoil, and other similar materials deposited or stored in the flood plain must be protected from erosion by vegetative cover, mulching, riprap or other acceptable method. Permanent sand and gravel operations and similar uses must be covered by a long-term site development plan.
(2) Temporary placement of fill, other materials, or equipment which would cause an increase to the stage of the one percent (1%) chance or regional flood may only be allowed if the City Council has approved a plan that assures removal of the materials from the floodway based upon the flood warning time available.
(C) Accessory structures. Accessory structures, as identified in § 152.042(A), may be permitted, provided that:
(1) Structures are not intended for human habitation;
(2) Structures will have a low flood damage potential;
(3) Structures will be constructed and placed so as to offer a minimal obstruction to the flow of flood waters;
(4) Structures must be elevated on fill or structurally dry flood proofed and watertight to the regulatory flood protection elevation. Certifications consistent with § 152.111(C) shall be required;
(5) As an alternative, an accessory structure may be flood proofed in a way to accommodate internal flooding. To allow for the equalization of hydrostatic pressure, there shall be a minimum of two (2) openings on at least two (2) sides of the structure and the bottom of all openings shall be no higher than one (1) foot above grade. The openings shall have a minimum net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding, have a net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding, and shall allow automatic entry and exit of floodwaters without human intervention. A floodproofing certification consistent with § 152.111(C) shall be required.
(D) Structural works for flood control that will change the course, current or cross section of protected wetlands or public waters are subject to the provisions of M.S. § 103G.245.
(E) A levee, dike or floodwall constructed in the floodway must not cause an increase to the one percent (1%) chance or regional flood. The technical analysis must assume equal conveyance or storage loss on both sides of a stream.
(Ord. 481, passed 2-16-2021)