(A) Floodway (F1).
(1) Within any floodway area, no encroachments, including fill, new construction, substantial improvements, or other development shall be permitted unless it has been demonstrated through hydrologic and hydraulic analysis performed in accordance with standard engineering practice that the proposed encroachment will not result in any increase in the base flood elevation.
(2) Because floodways present increased risk to human life and property due to their relatively faster and deeper flowing waters the floodway shall be preserved to the greatest extent possible.
(a) New development shall not be permitted in the floodway where reasonable alternatives exist elsewhere. In addition to the requirements below the applicant shall demonstrate that there are no reasonable alternatives other than the floodway encroachment before a permit is issued.
(b) When the floodway is the only reasonable alternative the applicant shall demonstrate that the floodway encroachment is the minimum necessary to accomplish the project.
(c) All permitted uses, activities, and development shall be undertaken in strict compliance with the flood-proofing and related provisions contained herein, and in all other applicable codes, ordinances, and regulations.
(B) Floodway fringe (F2). Within any floodway fringe areas, any development and/or use of land shall be permitted; provided that all such uses, activities, and/or development shall be undertaken in strict compliance with the flood-proofing and related provisions contained herein and in all other applicable codes, ordinances, and regulations.
(C) AE Zone without floodway. Within any AE without floodway area, no new construction or development shall be allowed unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the elevation of the 100-year flood more than one foot at any point. This requirement can be satisfied by utilization of the floodway area where determined.
(D) Approximated floodplain (Zone A). Within any approximated floodplain area:
(1) The Floodplain Administrator shall use elevation and floodway information from federal, state, or other acceptable sources when available to determine the elevation above which development will be reasonably safe from flooding; and
(2) (a) When data from an acceptable source is not available, the Floodplain Administrator shall review, or shall cause to be reviewed; all proposed development to determine the amount being invested and the specific flood risk at the site. The Floodplain Administrator shall then require the applicant to determine the elevation above which the development will be reasonably safe from flooding using the techniques set forth in the city’s approximate A Zone administrative procedures.
(b) When hydrologic and hydraulic analyses are required, they shall only be undertaken by a registered professional engineer who shall certify that the methods used correctly reflect currently accepted technical concepts. The resultant study shall include a cover letter, signed by the responsible professional, providing a statement of findings in basic terms. In addition, studies, analyses, computations, and the like shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
(3) Any development and/or use of land shall be permitted provided that all such uses, activities, and/or development shall be undertaken in strict compliance with the flood-proofing and related provisions contained herein and in all other applicable codes, ordinances, and regulations.
(E) Alteration or relocation of a stream.
(1) Whenever a developer intends to alter or relocate a stream within the floodplain area, the developer shall notify, in writing, by certified mail, the city’s Floodplain Administrator, the State Coordinating Office, any adjacent communities and any adjacent property owners of all such intended activities prior to the alteration or relocation of the stream. Copies of all required notifications must be submitted to the Federal Insurance Administration. In addition prior to issuing the local permit, the Floodplain Administrator shall require copies of all necessary permits from those governmental agencies from which federal or state law requires approval. Contact information for state and federal permitting authorities as well as addresses for required notification of appropriate county, state, and federal government agencies are contained in the city’s stream alteration administrative procedures.
(2) The developer shall also assure the city in writing that the flood carrying capacity within the altered or relocated portion of the stream will be maintained. The Floodplain Administrator may require the applicant to demonstrate that the altered or relocated portion of stream will provide equal or greater conveyance than the original stream segment. If hydrologic and hydraulic analyses are required, they shall only be undertaken by a registered professional engineers, who shall certify that the methods used correctly reflect currently accepted technical concepts. The resultant study shall include a cover letter, signed by the responsible professional, providing a statement of findings in basic terms. In addition, studies, analyses, computations, and the like shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
(3) Alteration of a stream includes placement of culverts, bridges, or other stream crossings. The Floodplain Administrator may require the use of certain best practice techniques in the construction of bridges, culverts, or stream crossings to prevent damage, loss of stream crossings, and localized flooding caused by blockage. These techniques may include, but are not limited to, wing walls, trash grates, or requiring openings to be of sufficient size to pass debris and/or anticipated future increases in flood heights.
(4) All new and replacement bridges, culverts, and other stream crossings shall adhere to the relevant anchoring requirements contained in this chapter.
(5) The developer is required to provide the community a legal agreement detailing all scheduled inspections and maintenance to be performed on altered or relocated watercourses, including culverts, bridges, and other stream crossings. It shall be the responsibility of the applicant to transfer this agreement to the new owner when the land associated with the watercourse alteration is transferred. A copy of all new agreements shall be provided to the Floodplain Administrator. Failure to transfer the agreement and provide a signed copy to the Floodplain Administrator shall subject the violator to the penalties set forth in § 156.999.
(6) The applicant must submit any maps, computations, or other material required by the Federal Emergency Management Agency (FEMA) to revise the flood insurance study and/or flood insurance rate maps, when notified by the Floodplain Administrator, and must pay any fees or other costs assessed by FEMA for this purpose.
(Ord. passed 5-4-1992; Ord. passed 2-8-2010)