22-19 - Amend Chapter 1308 flood damage prevention following FEMA flood zone update - ordinance

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elevations exist from any authoritative source, the flood protection ele- vation can be historical flood elevations, or base flood elevations deter- mined and/or approved by the Floodplain Administrator. (q) "Floodway" means the channel of a river or other watercourse and the adjacent land areas that have been reserved in order to pass the base flood discharge. A floodway is typically determined through a hydraulic and hydrologic engineering analysis such that the cumulative increase in the water surface elevation of the base flood discharge is no more than a designated height. In no case shall the designated height be more than one foot at any point within the community. The floodway is an extremely hazardous area, and is usually charac- terized by any of the following: Moderate to high velocity flood waters, high potential for debris and projectile impacts, and moderate to high erosion forces. (r) "Freeboard" means a factor of safety usually expressed in feet above a flood level for the purposes of floodplain management. Free- board tends to compensate for the many unknown factors that could con- tribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, obstructed bridge openings, debris and ice jams, and the hydrologic effect ofurban- ization in a watershed. (s) "Historic structure" means any structure that is: (1) Listed individually in the National Register of Historic Places (a listing maintained by the U.S. Department of Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listings on the National Register; (2) Certified or preliminarily determined by the Secretary of the Inte- rior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic distr ict; or (3) Individually listed on the State of Ohio's inventory of historic places maintained by the Ohio Historic Preservation Office. (t) "Hydrologic and hydraulic engineering analysis" means an analysis performed by a professional engineer, registered in the State of Ohio, in accordance with standard engineering practices as accepted by FEMA, used to determine flood elevations and /or floodway boundaries. (u) "Letter of Map Change (LOMC)" means an official FEMA deter- initiation, by letter, to amend or revise effective Flood Insurance Rate Maps, Flood Boundary and Floodway Maps, and Flood Insurance Stud- ies. LOMCs are broken down into the following categories: (1) Letter of Map Amendment (LOMA). A revision based on technical data showing that a property was incor- rectly included in a designated special flood hazard area. A LOMA amends the current effective Flood Insurance Rate Map and establishes that a specific property is not located in a special flood hazard area. (2) Letter of Map Revision (LOMR). A revision based on technical data that, usually due to manmade changes, shows changes to flood zones, flood elevations, floodplain and floodway delineations, and planimetric features. One common type of LOMR, a LOMB -F, is a determination concerning whether a structure or parcel has been elevated by fill above the base flood elevation and is, therefore, excluded from the special flood hazard area. (3) Conditional Letter of Map Revision (CLOMR). A formal review and comment by FEMA as to whether a proposed project complies with the minimum National Flood Insurance Program floodplain management criteria. A CLOMR does not amend or revise