(A) Conditional uses. The following shall be conditional uses in the FW Floodway District.
(1) Structures accessory to the uses listed in § 153.040(A) above and the uses listed in this division.
(2) Extraction and storage of sand, gravel, and other materials.
(3) Marinas, boat rentals, docks, piers, wharves, and water control structures.
(4) Railroads, streets, bridges, utility transmission lines, and pipelines.
(5) Storage yards for equipment, machinery, or materials.
(6) Placement of fill.
(7) Travel trailers and travel vehicles either on individual lots of record or in existing or new subdivisions or commercial or condominium type campgrounds, subject to the exemptions and provisions of § 153.102.
(8) Structural works for flood control, such as levees, dikes and flood walls constructed to any height where the intent is to protect individual structures and levees or dikes where the intent is to protect agricultural crops for a frequency flood event equal to or less than the 100-year frequency flood event.
(B) Standards for Floodway conditional uses.
(1) All uses. No structure (temporary or permanent), fill (including fill for roads and levees), deposit, obstruction, storage of materials or equipment, or other uses may be allowed as a conditional use that will cause any increase in the stage of the 100-year or regional flood or cause an increase in flood damages in the reach or reaches affected.
(2) Conditional use procedures. All Floodway conditional uses shall be subject to the procedures and standards contained in § 153.118 of this chapter.
(3) Underlying district. The conditional use shall be permissible in the underlying zoning district if one exists.
(4) Fill.
(a) Fill, dredge spoil and all other similar materials deposited or stored in the floodplain shall be protected from erosion by vegetative cover, mulching, riprap or other acceptable method.
(b) Dredge spoil sites and sand and gravel operations shall not be allowed in the floodway unless a long-term site development plan is submitted which includes an erosion/sedimentation prevention element to the plan.
(c) As an alternative, and consistent with division (B)(4)(b) of this section immediately above, dredge spoil disposal and sand and gravel operations may allow temporary, on-site storage of fill or other materials which would have caused an increase to the stage of the 100-year or regional flood but only after the governing body has received an appropriate plan which assures the removal of the materials from the floodway based upon the flood warning time available. The conditional use permit must be title registered with the property in the Office of the County Recorder.
(5) Accessory structures.
(a) Accessory structures shall not be designed for human habitation.
(b) Accessory structures, if permitted, shall be constructed and placed on the building site so as to offer the minimum obstruction to the flow of flood waters.
1. Whenever possible, structures shall be constructed with the longitudinal axis parallel to the, direction of flood flow.
2. So far as practicable, structures shall be placed approximately on the same flood flow lines as those of adjoining structures.
(c) Accessory structures shall be elevated on fill or structurally dry floodproofed in accordance with the FP-1 or FP-2 floodproofing classifications in the State Building Code. As an alternative, an accessory structure may be floodproofed to the FP-3 or FP-4 floodproofing classification in the State Building Code, provided the accessory structure constitutes a minimal investment, does not exceed 500 square feet in size, and for a detached garage, the detached garage must be used solely for parking of vehicles and limited storage. All floodproofed accessory structures must meet the following additional standards, as appropriate.
1. The structure must be adequately anchored to prevent flotation, collapse or lateral movement of the structure, and shall be designed to equalize hydrostatic flood forces on exterior walls.
2. Any mechanical and utility equipment in a structure must be elevated to or above the Regulatory Flood Protection Elevation or properly floodproofed.
(6) Storage of materials and equipment.
(a) The storage or processing of materials that are, in time of flooding, flammable, explosive, or potentially injurious to human, animal, or plant life is prohibited.
(b) Storage of other materials or equipment may be allowed if readily removable from the area within the time available after a flood warning, and in accordance with a plan approved by the governing body.
(7) Structural works. Structural works for flood control that will change the course, current or cross-section of protected wetlands or public waters shall be subject to the provisions of M.S. Chapter 105, as it may be amended from time to time. Community-wide structural works for flood control intended to remove areas from the regulatory floodplain shall not be allowed in the floodway.
(8) Avoidance of increase in flood level. A levee, dike or floodwall constructed in the floodway shall not cause an increase to the 100-year or regional flood and the technical analysis must assume equal conveyance or storage loss on both sides of a stream.
(Ord. 197, passed 2-26-1990) Penalty, see § 10.99