(a) Floodway.
(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 would not result in any increase in flood levels within the City of Spencer 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, etc., shall be submitted in sufficient detail to allow a through technical review by the Floodplain Administrator.
(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.
D. 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 City of Spencer, 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 areas as measured from the top of the bank nearest the site to the upland limit of the 1% annual chance special flood hazard area boundary.
(b) Floodway Fringe. Within the Floodway Fringe area 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 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 (1) foot at any point. This requirement can be satisfied by utilization of the floodway where determined.
(d) Approximated Floodplain (Zone A).
(1) Within any Approximated Floodplain:
A. 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.
B. 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:
1. The amount being invested and,
2. 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 elevation data, hydrologic and hydraulic analyses or other techniques. 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, etc. shall be submitted in sufficient detail to allow a thorough technical review by the Floodplain Administrator.
C. 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.
(2) See appendix 4.4 for Sample “Approximated floodplain (Zone A) techniques”.
(e) 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 City of Spencer, 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 (FEMA). 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.
See appendix 4.5 for Sample “Stream Alteration process and contact sheet”.
(2) The developer shall also assure the City of Spencer 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 a 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 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, etc, shall be submitted in sufficient detail to allow a through 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 Ordinance.
(5) The developer is required to provide the City of Spencer a legal agreement detailing all scheduled inspections and maintenance to be performed on altered or relocated watercourses includes 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 agreement shall be provided to the Floodplain Administrator. Failure to transfer the agreement and provide a signed copy of the Floodplain Administrator shall subject the violator to the penalties set forth in Section 1721.08(c).
(6) The applicant shall 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 shall pay any fees or other costs assessed by FEMA for this purpose.
(Passed 2-2-12)