(a) Floodway. Within any Floodway Area (F1), 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 would not result in any increase in flood levels during the occurrence of the base flood discharge. The resultant engineering study shall include a cover letter, signed and sealed by the responsible professional, providing a statement of findings in basic terms. In addition, studies, analyses, computations, and similar examinations shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
Because floodways present increased risk to human life and property due to their relatively faster and deeper flowing waters, the floodways shall be preserved to the greatest extent possible.
(1) 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.
(2) When the floodway is the only reasonable alternative, the applicant shall demonstrate that the floodway encroachment is the minimum necessary to accomplish the project.
(3) All permitted uses, activities, and development shall be undertaken in strict compliance with the flood proofing and related provisions contained in this article and in other applicable federal, state, and local laws, ordinances, rules, and regulations.
(4) In special flood hazard areas for which no regulatory floodway has been designated, the regulatory floodway for small, single lot development not incorporating significant amounts of fill can, at the discretion of the Floodplain Administrator, be determined to be the channel of the stream and the adjacent land areas to a distance of one-half the width of the special flood hazard area as measured from the top of the bank nearest the site to the upland limit of the one percent annual chance special flood hazard area boundary.
(b) AE Zone Without Floodway Area. Within any AE zone 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.
(c) Approximated Floodplain Area (Zone A).
Within any approximated floodplain area:
(1) The Floodplain Administrator shall use elevation and floodway information from federal, state, local, or other acceptable sources when available to determine the elevation above which development will be reasonably safe from flooding.
(2) 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 and adjacent properties, including but not limited to existing buildings, will be reasonably safe from flooding using hydrologic and hydraulic analyses or other techniques. When hydrologic and hydraulic analyses are required, they shall be prepared by a registered professional engineer who shall certify that the methods used correctly reflect currently accepted technical concepts. The resulting 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 similar examinations shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
(3) Any development and use of land shall be permitted provided that all such uses, activities, and development shall be undertaken in strict compliance with the flood-proofing and related provisions contained herein and in other applicable federal, state, and local laws, ordinances, rules, and regulations.
(4) Within any apportioned floodplain zone (zone A) without floodway area, no new construction or development shall be allowed unless it is demonstrated that the cumulative impact 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.
(d) Alteration or Relocation of a Stream.
(1) Whenever a developer intends to alter or relocate a stream within the special flood hazard area the developer shall notify in writing, by certified mail, the 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 Emergency Management Agency. 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.
(2) The developer shall also assure the City and the Floodplain Administrator 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 engineer, who shall certify that the methods used correctly reflect currently accepted technical concepts. The resulting 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 similar examinations shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
(3) Alteration of a stream includes placement of temporary or permanent 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 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 article.
(5) The developer is required to provide the City 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 the agreement to the purchaser 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 Subsection 1725.08(d).
(6) When any watercourse alteration has occurred, the applicant must submit copies of all maps, computations, and other material required by the Federal Emergency Management Agency (FEMA) to revise the flood insurance study (FIS) and Flood Insurance Rate Maps (FIRM) to the Floodplain Administrator. The applicant must pay all fees and other costs assessed by FEMA for this purpose.
(Ord. 2261. Passed 8-16-18.)