Use and Development of Floodway.
All development or use of the floodway is prohibited involving any encroachment, including fill, new construction or material improvement of any existing structure unless certification by a registered professional engineer is provided to and approved by the Department of Highways and Traffic that the development will not result in any increase in flood levels during occurrence of the base flood discharge. If and only if this Section is complied with, use or development of the floodway may be carried out subject to the restrictions of the remainder of this Article.
Use and Development Under Underlying District Regulations.
Property in this district may be used and developed in accordance with the regulations of the underlying zoning upon compliance with the following procedure:
(1) The property is placed in such conditions as to effectively and without increasing the flooding problems of other properties, remove the property from flooding based on the flood elevation study approved by the United States Federal Emergency Management Agency ("FEMA") and used as basic data for determining the boundaries of the Flood Hazard Boundary Map, being the "FP" Floodplain District as governed by this Section. Effective removal of the property from flooding requires provision of adequate freeboard as determined by the Department of Highways and Traffic in light of the reasonably anticipated ultimate development of the watershed. If the standards required by this Subsection are satisfactorily met in respect to any lot or tract of land in the "FP" Floodplain District, the property may then be used for such uses and under such regulations as are contained in the district regulations of the district designated after the "FP" code designation as the underlying district for the particular property.
(2) (a) The property owner or user shall submit to the Department of Highways and Traffic a plan for flood protection. The plan shall be approved if its implementation would adequately protect against the amount of water that would flow past the property in cubic feet per second during the base flood, as determined by the flood elevation study approved by FEMA and used as basic data for determining the boundaries of the Flood Insurance Rate Map and the Flood Hazard Boundary Map, and if the plan further demonstrates that its implementation will not increase the flooding problems of other properties. With respect to any stream for which a floodway has not been designated, except the Mississippi River, the flooding problems of other properties will be deemed increased if implementation of the plan would decrease the water storage or conveyance capacity of the stream.
(b) The plan must include a report by a registered professional engineer of demonstrated competence in hydrology as to the adequacy of the proposed plan for flood protection relative to the elevation of the floodplain and the flow as determined in the flood elevation study approved by FEMA, the effect of the proposed improvement on the flood problems of other properties, and such other hydrologic problems as may result from the improvements. Where the plan only delineates the floodplain elevation on the ground and no change or construction is proposed involving land below the floodplain elevation, the plan may be submitted under the seal of a registered land surveyor.
(c) The Department of Highways and Traffic may require such additional data or engineering studies from the applicant as may be necessary to determine the adequacy of the proposed plan for flood protection.
Use and Development in the "FP" Floodplain District.
No use or development in this district shall increase the flooding problems of other properties. Prior to any use or development of property pursuant to the permitted or conditional uses designated in this district, if such use or development involves manmade change to real property below the flood elevation, including construction or erection of any building or structure, or any filling, grading, paving, mining, dredging, excavation or drilling, the following procedure shall be complied with:
(1) The property owner or user shall submit to the Department of Highways and Traffic a development plan. The plan shall be approved if it demonstrates that its implementation will not increase the flooding problems of other properties. With respect to any stream for which a floodway has not been designated, the flooding problems of other properties will be deemed increased if implementation of the plan would decrease the water storage or conveyance capacity of the stream.
(2) The plan shall include a report by a registered professional engineer of demonstrated competence in hydrology as to the adequacy of the proposed plan to avoid flooding problems of other properties and such other hydrologic problems as may result from the improvements. Where the plan only delineates the floodplain elevation on the ground and no change or construction is proposed involving land below the floodplain elevation, the plan may be submitted under the seal of a registered land surveyor.
(3) The Department of Highways and Traffic may require such additional data or engineering studies from the applicant as may be necessary to determine the adequacy of the proposed plan.
Effect of Plan Approval.
(a) The approval by the Department of Highways and Traffic of such plans for flood protection does not constitute a representation, guarantee or warranty of any kind by St. Louis County, the Department of Highways and Traffic, the St. Louis County Planning Commission or by any officer or employee of either as to the practicality or safety of any protective measure and shall create no liability upon or cause of action against such public body, officers or employees for any damage that may result pursuant thereto.
(b) Approval of the plan by the Department of Highways and Traffic does not relieve an owner or user from fulfilling the requirements set forth in any other County ordinance regarding construction or development within the floodplain.
