[R.O. 2008 § 415.020; R.O. 2007 § 415.020; Ord. No. 4974 § 1, 3-30-2006; Ord. No. 6206 § 2, 4-28-2016]
The Legislature of the State of Missouri has in Section 89.020, RSMo, delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety and general welfare of its citizenry. Therefore, the City Council of O'Fallon, Missouri, does ordain as follows.
[R.O. 2008 § 415.030; R.O. 2007 § 415.030; Ord. No. 4974 § 1, 3-30-2006; Ord. No. 6170 § 1, 1-14-2016; Ord. No. 6206 § 3, 4-28-2016; Ord. No. 6737, 12-10-2020]
A. 
Flood Losses Resulting From Periodic Inundation. The special flood hazard areas of certain areas in the City of O'Fallon are subject to periodic inundation which results in loss of life, 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 which adversely affect the public health, safety and general welfare.
B. 
General Causes Of The Flood Losses. These flood losses are caused by the cumulative effect of urbanization of watersheds and obstructions in floodplains causing increases in flood heights and velocities and by the occupancy in flood hazard areas by uses vulnerable to floods or hazardous to others which are inadequately elevated, flood proofed or otherwise protected from flood damages.
C. 
Methods Used To Analyze Flood Hazards. The Flood Insurance Study (FIS) that is the basis of this Chapter uses a standard engineering method of analyzing flood hazards which consist of a series of interrelated steps.
1. 
Selection of a base flood that is based upon engineering calculations which permit a consideration of such flood factors as its expected frequency of occurrence, the area inundated and the depth of inundation. The base flood selected for this Chapter is representative of large floods which are characteristics 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 have a one percent (1%) chance of occurrence in any one (1) year as delineated on the Federal Emergency Management Agency's FIS (Flood Insurance Study) and illustrative materials dated March 9, 2021, as amended, and any future revisions thereto.
2. 
Calculations of water surface profiles are based on a standard hydraulic engineering analysis of the capacity of the stream channel and overbank areas to convey the regulatory flood.
3. 
Computation of a floodway required to convey this flood without increasing flood heights more than one (1) foot at any point.
4. 
Delineation of floodway encroachment lines within which no development is permitted that would cause any increase in flood height.
5. 
Delineation of flood fringe, i.e., that area outside the floodway encroachment lines, but still subject to inundation by the base flood.
[R.O. 2008 § 415.040; R.O. 2007 § 415.040; Ord. No. 4974 § 1, 3-30-2006; Ord. No. 6206 § 4, 4-28-2016]
A. 
It is the purpose of this Chapter to promote the public health, safety and general welfare and to minimize public and private losses described in Article II, Section 415.030(A); to establish or maintain the community's eligibility for participation in the National Flood Insurance Program (NFIP) as defined in 44 Code of Federal Regulations (CFR) 59.22(a)(3); and to meet the requirements of 44 CFR 60.3(d) by applying the provisions of this Chapter to:
1. 
Restrict or prohibit uses that are dangerous to health, safety, or property in times of flooding or cause undue increases in flood heights or velocities;
2. 
Requires uses vulnerable to floods, including public facilities that serve such uses, be provided with flood protection at the time of initial construction; and
3. 
Protect individuals from buying lands that are unsuited for the intended development purposes due to the flood hazard.
[R.O. 2008 § 415.050; R.O. 2007 § 415.050; Ord. No. 4974 § 1, 3-30-2006]
A. 
In order to accomplish its purpose, this Chapter includes methods and provisions for:
1. 
Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion or to flood heights or velocities.
2. 
Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction.
3. 
Controlling the alteration of natural floodplains, stream channels and natural protective barriers which are involved in the accommodation of floodwaters.
4. 
Controlling filling, grading, dredging and other development which may increase erosion or flood damage.
5. 
Preventing or regulating the construction of flood barriers which will unnaturally divert floodway waters or which may increase flood hazards in other areas.