(A) Permitted uses. The following uses are permitted within the Floodway District to the extent they are not prohibited by any other ordinance or underlying zoning district regulation and provided they do not require placement of structures, manufactured homes, fill or other obstruction, the storage of materials or equipment, excavation or alteration of a watercourse.
(1) Agricultural uses such as general farming, pasture, grazing, outdoor plant nurseries, horticulture, viticulture, truck farming, forestry, sod farming and wild crop harvesting;
(2) Industrial/commercial uses such as loading areas, parking areas and airport landing strips;
(3) Private and public recreational uses such as golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, boat launching ramps, swimming areas, parks, wildlife and nature preserves, game farms, fish hatcheries, shooting preserves, target ranges, trap and skeet ranges, hunting and fishing areas, hiking and horseback riding trails;
(4) Residential uses such as lawns, gardens, parking areas and play areas; and
(5) Other open space uses similar in nature to the above uses.
(B) Conditional uses. The following uses which involve structures (temporary or permanent), fill, storage of materials or equipment, excavation or alteration of a watercourse may be permitted only upon issuance of a conditional use permit by the Board of Adjustment as provided for in § 156.19. The uses must also meet the applicable provisions of the Floodway District performance standards.
(1) Uses or structures accessory to open space uses;
(2) Circuses, carnivals and similar transient amusement enterprises;
(3) Drive-in theatres, new and uses car lots, roadside stands, signs and billboards;
(4) Extraction of sands, gravel and other materials;
(5) Marinas, boat rentals, docks, piers and wharves;
(6) Utility transmission lines, underground pipelines; and
(7) Other uses similar in nature to uses described in this division and in division (A) above which are consistent with the provisions of division (C) below and with the general spirit and purpose of this chapter.
(C) Performance standards. All Floodway District uses allowed as a permitted or conditional use shall meet the following standards:
(1) No development shall be permitted in the Floodway District that would result in any increase in the base flood elevation. Consideration of the effects of any development on flood levels shall be based upon the assumption that an equal degree of development would be allowed for similarly situated lands;
(2) All development within the Floodway District shall:
(a) Be consistent with the need to minimize flood damage;
(b) Use construction methods and practices that will minimize flood damage; and
(c) Use construction materials and utility equipment that are resistant to flood damage.
(3) No development shall affect the capacity or conveyance of the channel or floodway or any tributary to the main stream, drainage ditch or any other drainage facility or system;
(4) Sanitary and utility systems, if permitted, shall meet the applicable performance standards of the Flood Fringe District and shall be constructed or aligned to present the minimum possible resistance to flood flows;
(5) No structures, buildings, or recreational vehicles shall be permitted unless the following conditions are met:
(a) No new structure shall be for human habitation.
(b) Any new structure shall meet the applicable performance standards of the Floodway Fringe District and shall be constructed or aligned to present the minimum possible resistance to flood flows.
(c) The development must not cause any increase in the base flood elevation. This must be proven by a hydraulic analysis conducted by a registered professional engineer in the State of Iowa, the result of which is a No Rise certificate.
(6) Any new addition to a structure shall only be permitted if the following conditions are met:
(a) Any building addition, regardless of size, shall meet the applicable performance standards of division (5)(b), as noted above.
(b) Any building addition, regardless of size, shall meet the applicable performance standards of division (5)(c), as noted above.
(7) Storage of materials or equipment that is buoyant, flammable, explosive or injurious to human, animal or plant life is prohibited. Storage of other material may be allowed if readily removable from the Floodway District within the time available after flood warning;
(8) Watercourse alterations or relocation (channel charges and modifications) must be designed to maintain the flood carrying capacity within the altered or relocated portion. In addition, the alterations or relocations must be approved by the Department of Natural Resources;
(9) Fill within the Floodway District shall comply with the following standards:
(a) No net loss of natural floodplain storage, or increase in water surface elevations during the base flood, as certified by a professional engineer in the State of Iowa;
(b) The volume of the loss of floodwater storage due to filling in the Floodway District shall be offset by providing an equal volume of flood storage by excavation or other compensatory measures at or adjacent to the development site;
(c) The total height of fill placed in a floodway must be three feet or less, with the exception of levees (which may include more fill if approved by the engineer);
(d) The extent of fill placed in the floodway shall not exceed 25% of the parcel area.
(10) Pipeline river or stream crossings shall be buried in the streambed and banks or otherwise sufficiently protected to prevent rupture due to channel degradation and meandering or due to the action of flood flows.
(1999 Code, § 160.10) (Ord. 2442, passed 4-26-2011; Ord. 2638, passed 4-28-2020; Ord. 2649, passed 7-14-2020; Ord. 2721, passed 2-28-2023) Penalty, see §
10.99