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

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by the 100 -year flood in any given year; base flood elevations are deter- mined. (3) Zone AO: Special flood hazard areas inundated by the 100 -year flood in any given year; with flood depths of 1 to 3 feet (usually sheet flow on sloping terrain); average depths are determined. (4) Zone AH: Special flood hazard areas inundated by the 100 -year flood in any given year; flood depths of I to 3 feet (usually areas of ponding); base flood elevations are determined. (5) Zone A99: Special flood hazard areas inundated by the 100 -year flood to be protected from the 100 -year flood by a Federal flood protec- tion system under construction; no base flood elevations are determined. (6) Zone B and Zone X (shaded): Areas of 500 -year flood; areas sub- ject to the 100 -year flood with average depths of less than 1 foot or with contributing drainage area less than 1 square mile; and areas protected by levees from the base flood. (7) Zone C and Zone X (unshaded): Areas determined to be outside the 500 -year floodplain. (8) Zone V: Coastal special flood hazard area subject to a 100 -year flood from velocity hazard (wave action); base flood elevations are not determined. (9) Zone VE and V 1 -30: Coastal special flood hazard area subject to a 100 -year from velocity hazard (wave action); base flood elevations are determined. (s) Flood Insurance Study (FIS). The official report in which the Fed- eral Emergency Management Agency or the U.S. Department of Hous- ing and Urban Development has provided flood profiles, floodway boundaries (sometimes shown on Flood Boundary and Floodway Maps), and the water surface elevations of the base flood. (t) Floodproofm¢. Any combination of structural and non - structural additions, changes, or adjustments to structures which reduce or elimi- nate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents. (u) Flood Protection Elevation. The Flood Protection Elevation, or FPE, is the base flood elevation plus one foot of freeboard. In areas where no base flood elevations exist from any authoritative source, the flood protection elevation can be historical flood elevations, or base flood elevations determined and/or approved by the floodplain adminis- trator. (v) Floodway. A floodway is the channel of a river or other water- course 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 dis- charge is no more than a designated height. In no case shall the desig- nated height be more than one foot at any point within the City. 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. (w) Freeboard. A factor of safety usually expressed in feet above a flood level for the purposes of floodplain management. Freeboard tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, obstructed bridge open- ings, debris and ice jams, and the hydrologic effect of urbanization in a watershed. 25