1177.02 FINDINGS OF FACT.
(a) Flood Losses Resulting From Periodic Inundation. The flood hazard areas of Mayfield Village are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base all of which adversely affect the public health, safety and general welfare.
(b) General Causes of Flood Losses. These flood losses are caused by:
(1) The cumulative effect of obstructions in flood plains, causing increased flood heights and velocities;
(2) The occupancy of flood hazard areas by uses vulnerable to floods or hazardous to others which are inadequately elevated or otherwise protected from flood damages.
(c) Methods Used to Analyze Flood Hazards. This chapter relies upon a two-step process for reasonably analyzing the flood hazard affecting specific lands. The Official Zoning Map adopted as part of this chapter by Section 1177.06 provides the first step by delineating a Regional Flood Plain District determined to be subject to flooding, based upon evidence of past flood events as shown on Flood Insurance Study and Flood Insurance Rate Map provided by F.I.A. The following information has been used to delineate this district: soil maps, historic flood maps, topographic studies and such other aids as the Village Engineer shall determine.
When specific information becomes available to designate separate Floodway and Floodway Fringe Districts, this Regional Flood Plain District may be separated into the two districts. In areas where this designation has not yet been made the second step involves a determination of the flood hazard at the site of any proposed special exception use. All uses, other than open space uses, are special exception uses under the terms of Section 1177.13(b) and require a case by case evaluation by the Board of Appeals, with expert technical assistance where necessary. The Board shall, where applicable:
(1) Estimate the discharge of the regional flood which is representative of large floods known to have occurred in this region and which are reasonably characteristic of what can be expected to occur on the particular streams subject to this chapter. It is in the general order of a flood which could be expected to occur on the average once every 100 years.
(2) Determine the specific flooding threat at the site of the proposed special exception use and determine whether the use is located in a floodway or floodway fringe area by:
A. Calculation of water surface elevations and flood protection elevations based upon hydraulic analysis of the capacity of the stream channel and overbank areas to convey the regional flood. Flood protection elevations shall be one foot above the water surface elevations of the regional flood.
B. Computation of the floodway required to convey this flood without increasing flood heights to an extent which would cause substantial upstream or downstream damage to existing or reasonably anticipated future development. Computation of increases in flood heights caused by any encroachment shall be based upon the reasonable assumption that there will be an equal degree of encroachment on both sides of the stream within that reach. Generally, any increase in flood stages attributed to encroachments on the flood plain of any river or stream shall not exceed 0.5 feet in any one reach or for the cumulative effect of several reaches.
(3) Evaluate the effects of the proposed use upon the public health, safety and general welfare in light of the purposes of this chapter and the standards established herein and deny, grant or conditionally grant the application for the proposed use.
(Ord. 76-23. Passed 12-20-76.)