City of Chesterfield, MO Article 05 Flood Damage Prevention

Section 405.05.010 General Provisions.

[CC 1990 § 31-05-01; Ord. No. 2801 § 3 (Exh. A), 6-16-2014; Ord. No. 2828 § 1 (Att. A), 1-5-2015]

A. Statutory Authorization. The legislature of the State of Missouri has in Chapter 89, 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 the City of Chesterfield, Missouri, does ordain as follows in this Article.

B. Findings Of Fact.

1. The flood hazard areas of the City 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 of which adversely affect the public health, safety and general welfare.

2. These flood losses are caused by the cumulative effect of obstructions in floodplains causing increases in flood heights and velocities, and by the occupancy in flood hazard areas of uses vulnerable to floods or hazards to other lands which are inadequately elevated, floodproofed, or otherwise unprotected from flood damage.

C. Statement Of Purpose. It is the purpose of this Article to promote the public health, safety and general welfare and to minimize public and private losses due to flood conditions in specific areas by provisions designed to:

1. Protect human life and health;

2. Minimize expenditure of public money for costly control projects;

3. Minimize the need of rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

4. Minimize prolonged business interruptions;

5. Minimize damage to public facilities and utilities, such as water and gas mains, electrical, telephone and sewer lines, streets and bridges located in floodplains;

6. Help maintain a stable tax base by providing for the sound use and development of flood-prone areas in such a manner as to minimize future flood blight areas;

7. Ensure that potential home buyers are notified that property is in flood area; and

8. Ensure that those who occupy the special flood hazard areas assume responsibility for their actions.

D. Methods Of Reducing Flood Losses. In order to accomplish its purposes, this Article 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; and

5. Preventing or regulating the construction of flood barriers which will unnaturally divert floodway waters or which may increase flood hazards in other areas.

E. Lands To Which This Article Applies.

1. This Article shall apply to all lands within the jurisdiction of the City of Chesterfield identified as numbered and unnumbered A Zones, AE, AO, and AH Zones, on the Flood Insurance Rate Map (FIRM) for St. Louis County on Map Panels 29189C0135K, 29189C0145K, 29189C0160K, 29189C0163K, 29189C0164K, 29189C0165K, 29189C0170K, 29189C0178K, 29189C0186K, 29189C0188K, 29189C0277K, 29189C0281K, and 29189C0282K, as amended, and any future revisions thereto. In all areas covered by this Article, no development shall be permitted except through the issuance of a floodplain development permit, granted by the City Council or its duly designated representative under such safeguards and restrictions as the City Council or its duly designated representative may reasonably impose for the promotion and maintenance of the general welfare, health of the inhabitants of the community, and as specifically noted in Section 405.05.030.

2. This Article shall also apply to areas of 100-year high water in the Chesterfield Valley, and the supplemental protection area within the jurisdiction of the City of Chesterfield.

F. Methods Used To Analyze Flood Hazards.

1. The Flood Insurance Study (FIS) that is the basis of this Article uses a standard engineering method of analyzing flood hazards which consists of interrelated steps:

a. 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 Article is representative of large floods which are characteristic of what can be expected to occur on the particular streams subject to this Article. It is the general order of a flood which could be expected to have a one-percent-chance of occurrence in any one (1) year as delineated on the Federal insurance Administrator's FIS, and illustrative materials for St. Louis County, dated February 4, 2015, as amended, and any future revisions thereto.

b. Calculation of water surface profiles is based on a standard hydraulic engineering analysis of the capacity of the stream channel and overbank areas to convey the regulatory flood.

c. Computation of a floodway required to convey this flood without increasing flood heights more than one (1) foot at any point.

d. Delineation of floodway encroachment lines within which no development is permitted that would cause any increase in flood height.

e. Delineation of flood fringe, i.e., that area outside the floodway encroachment lines, but still subject to inundation by the base flood.

2. The current version of the Chesterfield Valley Master Stormwater Plan Model is hereby adopted by reference and declared to be part of this Article. Both the Flood Insurance Study and the Chesterfield Valley Master Stormwater Plan Model are on file at the City of Chesterfield City Hall.

3. In areas where both the special flood hazard area data and the Chesterfield Valley Master Stormwater Plan data apply, the higher of the base flood elevation or the 100-year high-water elevation in Chesterfield Valley shall be used.

4. The supplemental protection area is a 200-foot area immediately adjacent to the special flood hazard area or 100-year high-water area in the Chesterfield Valley which is hereby created to enhance the purposes of this Article, as stated in Section 405.05.010(C), by putting in place requirements to reduce the flood damage risk on those properties immediately adjacent to the special flood hazard areas. The requirements associated with this zone are intended to protect structures, principally those on properties that have been elevated by the placement of fill, against subsurface flood conditions and flooding from events that exceed the base flood elevation.

G. Penalties For Non-Compliance. See Article 08 of this Unified Development Code (UDC) for enforcement and penalties.

H. Abrogation And Greater Restrictions. This Article is not intended to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this Article and another conflict or overlap, whichever imposes the more stringent restrictions shall prevail.

I. Interpretation. In the interpretation and application of this Article, all provisions shall be:

1. Considered as minimum requirements;

2. Liberally construed in favor of the Governing Body; and

3. Deemed neither to limit or repeal any other powers granted under State statutes.

J. Warning And Disclaimer Of Liability. The degree of flood protection required by this Article is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by man-made or natural causes. This Article does not imply that land outside the special flood hazard areas or uses permitted within such areas will be free from flooding or flood damages. This Article shall not create liability on the part of the City of Chesterfield or any officer or employee thereof for any flood damages that result from reliance on this Article or any administrative decision lawfully made thereunder.

K. Non-Conforming Use.

1. A structure or the use of a structure or premises which was lawful before the passage or amendment of the Chapter, but which is not in conformity with the provisions of this Chapter, may be continued subject to the following conditions:

a. If such use is discontinued for twelve (12) consecutive months, any future use of the building premises shall conform to this Chapter.

b. Uses or adjuncts thereof which are or become nuisances, shall not be entitled to continue as non-conforming uses.

c. No such structure shall be expanded, changed, enlarged or altered in a way which increases its non-conformity.

2. If any non-confirming use or structure is destroyed by any means, including flood, it shall not be reconstructed if the cost is more than fifty percent (50%) of the market value of the structure before the damage occurred, unless it is reconstructed in conformity with the provisions of this Article. This limitation does not include the cost of any alteration to comply with existing State or local health, sanitary, building or safety codes or regulations or the cost of any alteration of a structure listed on the National Register of Historical places or a State Inventory of Historical Places.

L. Amendments.

1. The regulations, restrictions and boundaries set forth in this Article may from time to time be amended, supplemented, changed or appealed to reflect any and all changes in the National Flood Disaster Protection Act of 1973; provided, however, that no such action may be taken until after a public hearing in relation thereto, at which parties in interest and citizens shall have an opportunity to be heard. Notice of the time and place of such hearing shall be published in a newspaper of general circulation in the City of Chesterfield.

2. At least twenty (20) days shall elapse between the date of said publication and the public hearing. A copy of such amendments will be provided to the FEMA. The regulations of this Article are in compliance with the National Flood Insurance Program Regulations as published in Title 44 of the Code of Federal Regulations.

Section 405.05.020 Administration.

[CC 1990 § 31-05-02; Ord. No. 2801 § 3 (Exh. A), 6-16-2014; Ord. No. 2828, § 1 (Att. A), 1-5-2015]

A. Establishment Of A Development Permit. A development permit shall be obtained before construction or development begins, including the placement of manufactured homes, within any special flood hazard area or supplemental protection area established in Section 405.05.010(F). No person, firm, or corporation or unit of government shall initiate any development or substantial improvement or cause the same to be done without first obtaining separate permits for each development as defined in Article 10 of this UDC. Application for a development permit shall be made on forms furnished by the Director of Public Works (the Director) and may include, but not be limited to: plans in duplicate drawn to scale showing the nature, location, dimensions, and elevations of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities; and the location of the foregoing. Specifically, the following information is required:

1. Elevation in relation to mean sea level of the lower floor (including basement) of all structures;

2. Elevation in relation to mean sea level to which any non-residential structure is to be floodproofed;

3. Certification from a registered professional engineer or architect that the non-residential floodproofed structure will meet the floodproofing criteria in Section 405.05.030(C); and

4. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.

B. Designation Of The Local Administrator. The Director or his/her designee is hereby appointed to administer and implement the provisions of this Article by granting or denying development permit applications in accordance with its provisions.

C. Duties And Responsibilities Of The Director. Duties of the Director shall include, but not be limited to:

1. Review all development permits to assure that sites are reasonably safe from flooding and that the permit requirements of this Article have been satisfied.

2. Review permits for proposed development to assure that all necessary permits have been obtained from those Federal, State or local governmental agencies from which prior approval is required by Federal, State, or local law.

3. When base flood elevation data has not been provided in accordance with Section 405.05.010(F), then the Director shall obtain, review and reasonably utilize any base flood elevation or floodway data available from a Federal, State or other source in order to administer the provisions of this Article.

4. Verify, record and maintain record of the actual elevation (in relation to mean sea level) of the lowest floor (including basement) of all new or substantially improved structures.

5. Verify, record and maintain record of the actual elevation (in relation to mean sea level) to which the new or substantially improved non-residential structures have been floodproofed.

6. When floodproofing is utilized for a particular non-residential structure, the Director shall obtain certification from a registered professional engineer or architect.

7. Notify adjacent communities and the Missouri State Emergency Management Agency (MO SEMA) prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Emergency Management Agency.

8. Assure that maintenance is provided within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.

9. Where interpretation is needed as to the exact location of the boundaries of the special flood hazard areas (for example, where there appears to be a conflict between a mapped boundary and actual field conditions), the Director shall make the necessary interpretations. The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in this Section.

10. Serve notices of violation, issue stop-work orders, revoke permits, and take corrective actions necessary to achieve compliance with Section 405.05.030.

D. Variance Procedures.

1. The Board of Adjustment as established by the City of Chesterfield shall hear and decide appeals and requests for variances from the requirements of this Article.

2. The Board of Adjustment shall hear and decide appeals when it is alleged that there is an error in any requirement, decision or determination made by the Director of Public Works in the enforcement or administration of this Article.

3. Any person aggrieved by the decision of the Board of Adjustment or any taxpayer may appeal such decision to the Circuit Court of St. Louis County as provided in Chapter 89, RSMo.

4. In passing upon such applications, the Board of Adjustment shall consider all technical evaluations, all relevant factors, standards specified in other Sections of this Article, and:

a. The danger that materials may be swept onto other lands to the injury of others;

b. The danger to life and property due to flooding or erosion damage;

c. The susceptibility of a proposed facility and its contents to flood damage and the effect of such damage on the individual owner;

d. The importance of the services provided by the proposed facility to the community;

e. The necessity to the facility of a waterfront location, where applicable;

f. The availability of alternative locations, not subject to flooding or erosion damage, for the proposed use;

g. The compatibility of the proposed use with existing and anticipated development;

h. The relationship of the proposed use with existing and anticipated development;

i. The safety of access to the property in times of flood for ordinary and emergency vehicles;

j. The expected height, velocity, duration, rate of rise and sediment transport of the flow waters and the effects of wave action, if applicable, expected at the site; and

k. The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities, such as sewer, gas, electrical and water systems, and streets and bridges.

E. Conditions For Variances.

1. Generally, variances may be issued for a new construction and substantial improvements to be erected on a lot of one-half (1/2) acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, provided that the provisions of Subsection (E)(2) through (6) below have been fully considered. As the lot size increases beyond the one-half (1/2) acre, the technical justification required for issuing the variance increases.

2. Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historical Places or the State Inventory of Historical Places, without regard to the procedures set forth in the remainder of this Section.

3. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.

4. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.

5. Variances shall only be issued upon:

a. A showing of good and sufficient cause;

b. A determination that failure to grant the variance would result in exceptional hardship to the applicant; and

c. A determination that the granting of a variance will not result in increased flood heights, additional threats to public safety or extraordinary public expense, or will not create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances.

6. Any applicant to whom a variance is granted shall be given a written notice that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation.

Section 405.05.030 Provision For Flood Reduction.

[CC 1990 § 31-05-03; Ord. No. 2801 § 3 (Exh. A), 6-16-2014; Ord. No. 2828, § 1 (Att. A), 1-5-2015]

A. General Standards.

1. In all special flood hazard areas (Zones A, AE, A1-30, AO, AH) the following provisions are required:

a. All new construction, including manufactured homes and substantial improvements, shall be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

b. All new construction and substantial improvements shall be constructed with materials resistant to flood damage.

c. All new construction and substantial improvements shall be constructed by methods and practices that minimize flood damage.

d. All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

e. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system.

f. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters.

g. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

h. The storage or processing of materials that are in time of flooding buoyant, flammable, explosive or could be injurious to human, animal or plant life is prohibited.

i. Storage of other material or equipment may be allowed if not subject to major damage by floods and firmly anchored to prevent flotation or if readily removable from the area within the time available after flood warning.

j. That until a floodway has been designated, no development, including landfill, may be permitted within Zones A1-30 and AE on the City's FIRM unless the applicant for the land use has demonstrated that the proposed use, when combined with all other existing and reasonably anticipated uses, will not increase the water surface elevation of the 100-year flood more than one (1) foot on the average cross section of the reach in which the development or landfill is located as shown on the Flood Insurance Rate Study incorporated by reference, Section 405.05.010(F) of this Article.

2. All new construction and substantial improvements located within the supplemental protection area, as defined in Article 10 of this UDC, shall comply with the requirements of Section 405.05.030(C) of this Article.

B. Standards For Subdivision Proposals. All subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, shall be reviewed to determine whether such proposals will be reasonably safe from flooding. Any such subdivision proposal shall:

1. Minimize flood damage.

2. Include public utilities and facilities which are constructed so as to minimize flood damage.

3. Ensure adequate drainage is provided.

4. Include base flood elevations for any proposal which exceeds fifty (50) lots or five (5) acres.

C. Specific Standards. In all supplemental protection areas and special flood hazard areas where base flood elevation data has been provided as set forth in Section 405.05.010(F) or Section 405.05.020(C)(3) (Zones A1-30, AE and AH), the following provisions are required:

1. Residential Construction In Special Flood Hazard Areas Outside The Chesterfield Valley. New construction or substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to a minimum of two (2) feet above the base flood elevation.

2. Residential Construction In Special Flood Hazard Areas Inside The Chesterfield Valley. New construction or substantial improvement of any residential structure shall have the lowest floor elevated to a minimum of one (1) foot above both the base flood elevation and 100-year high-water elevation in the Chesterfield Valley as indicated in Section 405.05.010(F).

3. Non-Residential Construction In Special Flood Hazard Areas Outside The Chesterfield Valley. New construction or substantial improvement of any commercial, industrial or other non-residential structure shall either have the lowest floor, including basement, elevated to a minimum of two (2) feet above the level of the base flood elevation or, together with attendant utility and sanitary facilities, be floodproofed so that below such a level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this Subsection are satisfied. Such certification shall be provided to the official as set forth in Section 405.05.020(C)(6).

4. Non-Residential Construction In Special Flood Hazard Areas Inside The Chesterfield Valley. New construction or substantial improvement of any commercial, industrial or other non-residential structure shall either have the lowest floor elevated to a minimum of one (1) foot above both the level of the base flood elevation or 100-year high-water elevation in the Chesterfield Valley as indicated in Section 405.05.010(F), or together with the attendant utility and sanitary facilities, be floodproofed so that below such a level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this Subsection are satisfied. Such certification shall be provided to the official as set forth in Section 405.05.020(C)(6).

5. Residential And Non-Residential Construction In Special Flood Hazard Areas Outside The Chesterfield Valley And Within The Supplemental Protection Area.

a. New construction of any residential or non-residential structure shall meet the following requirements:

Table 1
Supplemental Protection Area Requirements: (Outside Chesterfield Valley)
Distance from the SFHA Boundary to Structure (feet)	Minimum Residential Lowest Floor/Sill Elevation1	Minimum Non-Residential Lowest Sill or Lowest Floor/Floodproofing Elevation1
0 to 49.99	Lowest floor 2 feet above BFE2	Lowest floor 2 feet above BFE
50 to 99.99	Lowest sill 2 feet above BFE	Lowest sill 2 feet above BFE
100 to 200	Lowest sill 1 foot above BFE	Lowest sill 1 foot above BFE

NOTES:
1	Including basement.
2	Lowest floor of proposed structures in subdivisions for which improvement plans were approved after October 1, 2005, and before February 28, 2006, shall be at least one (1) foot above the BFE.

b. Structures which existed in the supplemental protection area and were lawful prior to the passage of the above-listed requirements shall be allowed to remain insomuch as the structure remains unchanged. At such time that a non-conforming structure is razed or an addition added to the structure, the new construction or addition must meet the requirements of this Section.

6. Residential and non-residential construction in areas inside the Chesterfield Valley and within the supplemental protection area. New construction of any residential or non-residential structure shall meet the following requirements:

Table 2
Supplemental Protection Area Requirements (Inside Chesterfield Valley)
Distance from the SFHA Boundary or 100-Year High-Water to Structure (feet)	Minimum Residential Lowest Floor Elevation	Minimum Non-Residential Lowest Floor or Floodproofing Elevation
0 to 200	1 foot above BFE or 100-year high-water	1 foot above BFE or 100-year high-water

7. All New Construction And Substantial Improvements In The Special Flood Hazard Area. Fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria: A minimum of two (2) openings having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding shall be provided. The bottom of all openings shall be no higher than one (1) foot above grade. Openings may be equipped with screens, louvers, valves or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.

8. Manufactured Homes.

a. All manufactured homes shall be anchored to resist flotation, collapse, or lateral movement. Manufactured homes must be anchored in accordance with State and local building codes and FEMA guidelines. In the event that over-the-top frame ties to ground anchors are used, the following specific requirements (or their equivalent) shall be met:

(1) Over-the-top ties be provided at each of the four (4) corners of the manufactured home, with two (2) additional ties per side at intermediate locations and manufactured homes less than fifty (50) feet long requiring an additional tie per side;

(2) Frame ties be provided at each corner of the home with five (5) additional ties per side at intermediate points and manufactured homes less than fifty (50) feet long requiring four (4) additional ties per side;

(3) All components of the anchoring system be capable of carrying a force of four thousand eight hundred (4,800) pounds;

(4) Any additions to the manufactured home be similarly anchored.

b. Require that all manufactured homes within Zones A1-30, AH and AE on the community's FIRM be elevated on a permanent foundation such that the lowest floor of the manufactured home is a minimum of one (1) foot above the base flood elevations. The manufactured home chassis shall be supported by reinforcing piers or other foundation elements of at least equivalent strength that are no less than thirty-six (36) inches in height above grade and shall be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, in accordance with the provisions of Section 405.05.020(C).

9. Recreational Vehicles. Require that recreational vehicles placed on sites within the identified floodplain on the community's FIRM either:

a. Be on the site for fewer than one hundred eighty (180) consecutive days and be fully licensed and ready for highway use (NOTE: A recreational vehicle is ready for highway use if it is on its wheels or jacking system is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions); or

b. Meet the permit requirements and the elevation and anchoring requirements for manufactured homes of this Article.

10. Roadways. All roadways within and adjacent to the special flood hazard areas shall be constructed at least one (1) foot above the base flood elevation or 100-year high-water elevation in the Chesterfield Valley as indicated in Section 405.05.010(F). This requirement is only applicable to roadways constructed after the passage of these requirements. Repairs and improvements to roadways which were existing prior to passage of the above-listed requirements shall not be required to adhere to the requirements of this Section.

D. Floodways. Located within special flood hazard areas established in Section 405.05.010(F) are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles and erosion potential, the following provisions shall apply.

1. Prohibit encroachments, including fill, new construction, substantial improvements and other developments unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during occurrence of the base flood discharge.

2. If Section 405.05.030(D)(1) is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of Section 405.05.030.

3. In Zone A unnumbered, obtain, review and reasonably utilize any floodway data available through Federal, State and other sources in meeting the standards of this Article.

E. Areas Of Shallow Flooding (AO And AH Zones). Located within the special flood hazard areas established in Section 405.05.010(F), are areas designated as shallow flooding. These areas have special flood hazards associated with base flood depths of one (1) to three (3) feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate; therefore, the following provisions apply:

1. Within AO Zones.

a. All new construction and substantial improvements of residential structures shall have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as one (1) foot more than the depth number specified in feet on the community's FIRM [at least two (2) feet if no depth number is specified].

b. All new construction and substantial improvements of non-residential structures shall:

(1) Have the lowest floor (including basement) elevated above the adjacent grade at least as high as one (1) foot above the depth number specified in feet on the community's FIRM [at least two (2) feet if no depth number is specified]; or

(2) Together with attendant utility and sanitary facilities be completely floodproofed to or above that level so that any space below that level is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

c. Adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from proposed structures.

d. The anchoring requirements for manufactured homes as established in Section 405.05.030(C) shall be required.

2. Within AH Zone.

a. The specific standards for all special flood hazard areas where base flood elevation data has been provided shall be required as set forth in Section 405.05.030(C).

b. Adequate drainage paths around structures on slopes shall be required in order to guide floodwaters around and away from proposed structures.

F. Proof Of Compliance.

1. Certification of compliance from the Director is required after completion of work related to a development permit. In no case shall any structure be inhabited or occupied for use prior to such time as an elevation certificate has been submitted to and approved by the Department.

2. Penalties for violation of this requirement are listed in Article 08 of this UDC.

Section 405.05.040 Definitions.

[CC 1990 § 31-05-04; Ord. No. 2828, § 1 (Att. A), 1-5-2015]

A. Unless specifically defined below, words or phrases used in this Article shall be interpreted so as to give them the meaning they have in common usage and to give this Article its most reasonable application.

ACTUARIAL OR RISK PREMIUM RATES

Those rates established by the Administrator pursuant to individual community studies and investigations which are undertaken to provide flood insurance in accordance with Section 1307 of the Act and the accepted actuarial principles. Risk premium rates include provisions for operating costs and allowances.

APPEAL

A request for a review by the Director of Public Works.

AREA OF SHALLOW FLOODING

A designated AO or AH Zone on a community's Flood Insurance Rate Map (FIRM) with a one-percent or greater annual chance of flooding to an average depth of one (1) to three (3) feet, where a clearly defined channel is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

BASE FLOOD

The flood having a one-percent chance of being equaled or exceeded in any given year.

BASE FLOOD ELEVATION (BFE)

The water surface elevation of the base flood in relation to a specified datum, usually the National Geodetic Vertical Datum of 1929 or the North American Vertical Datum of 1988, and usually expressed in feet above mean seal level (MSL). This elevation is used for regulatory purposes in this Article.

BASEMENT

Any area of the structure having its floor below ground level on all sides.

CHESTERFIELD VALLEY

The area roughly bounded by the Missouri River on the north, Eatherton Road on the west, the Missouri Central Railroad on the south, and Bonhomme Creek on the east. Most of this area is encompassed by the Monarch-Chesterfield levee system:

DEVELOPMENT

Any man-made change to improved or unimproved real estate, including, but not limited to, building or other structures, mining, dredging, filling, grading, paving, excavation or drilling operation.

EXISTING CONSTRUCTION

For the purposes of determining rates, structures for which the start of construction commenced before the effective date of the FIRM or before January 1, 1975, for FIRMs effective before that date. "Existing construction" may also be referred to as "existing structures."

EXISTING MANUFACTURED HOME PARK OR SUBDIVISION

A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the floodplain management regulations adopted by the City of Chesterfield.

EXPANSION TO AN EXISTING MANUFACTURED HOME PARK OR SUBDIVISION

The preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).

FLOOD INSURANCE RATE MAP (FIRM)

An official map of a community on which the flood insurance study has delineated the flood hazard boundaries and the zones establishing insurance rates applicable to the community.

FLOOD INSURANCE STUDY

The official report provided by the Federal Emergency Management Agency. The report contains flood profile as well as the Flood Boundary/Floodway Map and the water surface elevation of the base flood.

FLOOD or FLOODING

A general and temporary condition of partial or complete inundation of normally dry land areas from:

a. The overflow of inland or tidal waters.

b. The unusual or rapid accumulation or runoff of surface waters from any source.

FLOODWAY FRINGE

That area of the floodplain, outside of the floodway, that on the average is likely to be flooded once every one hundred (100) years [i.e., that has a one-percent chance of flood occurrence in any one (1) year].

FLOODWAY or REGULATORY FLOODWAY

The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one (1) foot.

FREEBOARD

A factor of safety usually expressed in feet above a flood level for purposes of floodplain management. Freeboard tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated from a selected size flood and floodway conditions, such as wave action, clogged bridge openings, and the hydrological effect of urbanization of the watershed.

HIGHEST ADJACENT GRADE

The highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

HISTORIC STRUCTURE

Any structure that is:

a. Listed individually in the National Register of Historic Places (a listing maintained by the Department of the Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;

b. Certified or preliminarily determined by the Secretary of the Interior 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 district;

c. Individually listed on State inventory of historic places in states with historic preservation programs which have been approved by the Secretary of the Interior; or

d. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:

(1) By an approved State program as determined by the Secretary of the Interior; or

(2) Directly by the Secretary of the Interior in states without approved programs.

LOWEST FLOOR

The lowest enclosed area (including basement) of a structure. This definition excludes an enclosure below the lowest floor which is an unfinished or flood-resistant enclosure usable solely for parking of vehicles, building access or storage in an area other than a basement area, provided that such enclosure is built in accordance with the applicable design requirements specified in Section 405.05.030(C) for enclosures below the lowest floor.

LOWEST SILL

The member forming the lowest side of an opening by which surface water may enter a structure (e.g., window sill, door sill, etc.).

MANUFACTURED HOME

A structure, transportable in one (1) or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term "manufactured home" also includes park trailers, travel trailers, and other similar vehicles placed on a site for greater than one hundred eighty (180) consecutive days. For insurance purposes, the term "manufactured home" does not include park trailers, travel trailers, and other similar vehicles.

MANUFACTURED HOME PARK OR SUBDIVISION

A parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.

MARKET VALUE OF A STRUCTURE

The established value of the existing structure, as determined by the St. Louis County Department of Revenue for taxing purposes, prior to any improvements being made or prior to any flooding condition. The value of any land shall not be included in the value of the structure.

NEW CONSTRUCTION

Structures for which the start of construction or substantial improvement is commenced on or after the effective date of the FIRM.

NEW MANUFACTURED HOME PARK OR SUBDIVISION

A manufactured home park or subdivision for which the construction of facilities for serving the lot on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of floodplain management regulations adopted by the City of Chesterfield.

100-YEAR HIGH-WATER ELEVATION IN THE CHESTERFIELD VALLEY

Refers to the flood elevations throughout the Chesterfield Valley for a 100-year rainfall event as determined by the current version of the Chesterfield Valley Master Storm Water Plan Model.

RECREATIONAL VEHICLE

A vehicle which is:

a. Built on a single chassis.

b. Four hundred (400) square feet or less when measured at the largest horizontal projections.

c. Designed to be self-propelled or permanently towable by a light-duty truck.

d. Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel or seasonal use.

ROADWAY

Pavement designed and installed for the purpose of conveying vehicular traffic with the intent of providing access to legal land divisions. For the purpose of this Article, the term "roadway" does not refer to private driveway and parking areas.

SPECIAL FLOOD HAZARD AREA

The land in the floodplain subject to a one-percent or greater chance of flooding in any given year.

START OF CONSTRUCTION

For other than new construction or substantial improvements under the Coastal Barrier Resources Act (Pub. L. 97-3481), includes substantial improvement, and means the date the building permit was issued, provided that the actual start of construction, repair, reconstruction, placement or other improvement was within one hundred eighty (180) days of the permit date. The actual start means the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns or any work beyond the stage of excavation or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure.

STRUCTURE

A walled and roofed building that is principally above ground, as well as a manufactured home, and a gas or liquid storage tank that is principally above ground.

SUBSTANTIAL DAMAGE

Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damage condition would equal or exceed fifty percent (50%) of the market value of the structure before the damage occurred.

SUBSTANTIAL IMPROVEMENT

Any repair, reconstruction or improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure either before the improvement or repair is started, or if the structure has been damaged and is being restored, before the damage occurred. For the purpose of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either any project for improvement of a structure to comply with existing State or local health, sanitary or safety code specifications, or any alteration of a structure listed on the National Register of Historical Places or a State Inventory of Historical Places.

SUPPLEMENTAL PROTECTION AREA

Land located outside the special flood hazard area and within two hundred (200) feet of the special flood hazard area boundary or 100-year high-water elevation in the Chesterfield Valley as indicated in Section 405.05.010(F).

VARIANCE

A grant of relief to a person from the requirements of this Article which permits construction in a manner otherwise prohibited by this Article where specific enforcement would result in unnecessary hardship.

VIOLATION

The failure of a structure or other development to be fully compliant with the City of Chesterfield's floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required by this Article is presumed to be in violation until such time as that documentation is provided.