Polk County, IA Environmental Rules: Boat Dock Permits (2026)

Article 7, Section 1(I)(3) of the Polk County Zoning Ordinance lists boat launching ramps, boat docks, piers, bridges and bridge approaches, marinas, and stormwater detention facilities as uses permitted within floodways and floodway fringes, but only 'with certain additional standards,' not as a matter of right. Boat houses, boat storage buildings and operations, and boat sales or rental structures tied to those uses are permitted the same way, but the ordinance carves out boat or motor repair buildings and showrooms, which are not covered by this allowance.

Because a dock or ramp sits in a designated floodway or floodway fringe, it must also meet the Floodway Fringe Standards of Section 1(J): construction certified by a professional engineer registered in Iowa to withstand flood depths, pressures, velocities and impact forces of the 1% Annual Chance flood, with any portion below the flood elevation built watertight or with walls substantially impermeable to water. Before construction starts, the owner must secure a Floodplain Development Permit from the Zoning Administrator, showing the elevation of the 1% Annual Chance flood and the elevation of the lowest floor or floodproofed level relative to the 1988 North American Vertical Datum.

Because docks and ramps sit in the floodway itself, the strict floodway rule also applies: the floodway must remain permanent open space with 100 percent flood protection, so no dock or ramp may obstruct or reduce the floodway's flood-carrying capacity.