This section shall be known as the Floodplain Management Ordinance of the City of Norwalk and shall be cited as the Floodplain Management Ordinance.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application.
"Base flood"
means a flood that has a one percent chance of being equaled or exceeded in any given year (also called the "100-year flood").
"Base flood elevation"
means the elevation shown on the Flood Insurance Rate Map for Zones A that indicates the water surface elevation resulting from a base flood.
"Basement"
means any area of a building having its floor below ground level on all sides.
"Building"
means a structure.
"Development"
means any man made change to improved or unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation, or drilling operations or storage of equipment or materials.
"Exceptional hardship"
means a hardship that is unusual and peculiar to the property involved, and not involving mere economic or financial hardship alone, inconvenience, aesthetic considerations, personal preferences, or the disapproval of one's neighbors.
"Existing manufactured home park or subdivision"
means a manufactured home park or subdivision for which the construction of facilities 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 adoption of the ordinance codified in this chapter.
"Expansion to an existing manufactured home park or subdivision"
means the preparation of additional sites by the construction of facilities to service lots on which 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" or "flooding"
means:
1. 
A general and temporary condition of partial or complete inundation of normally dry land from: the overflow of inland or tidal waters; the unusual and rapid accumulation or runoff of surface waters from any source; or mudslides and mudflows which are proximately caused by flooding as defined herein and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current; or
2. 
The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusual and unforeseeable event which results in flooding as defined in this definition.
"Flood Boundary and Floodway Map"
means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the special flood hazard areas and the regulatory floodway.
"Flood Insurance Rate Map"
means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the special flood hazard areas and the risk premium zones applicable to the community.
"Flood Insurance Study"
means the official report provided by the Federal Insurance Administration that includes flood profiles, the Flood Insurance Rate Map, the Flood Boundary and Floodway Map, and the water surface elevation of the base flood.
"Floodplain"
means any land area susceptible to being inundated by flooding.
"Floodplain Administrator"
means the City Manager, or designee, who is hereby designated by the City to administer, implement, and enforce the floodplain management regulations.
"Floodplain management regulations"
means all applicable Federal, State, or local laws and regulations that provide standards for preventing and reducing flood loss and damage in the City, including, but not limited to this chapter and all other City zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as grading and erosion control), or any other ordinances or regulations that pertain to development in floodplains or flood-prone areas.
"Historic structure"
means any structure that is:
1. 
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;
2. 
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 of the Interior to qualify as a registered historic district;
3. 
Individually listed on a State Inventory of Historic Places in States with historic preservation programs which have been approved by the Secretary of the Interior; or
4. 
Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either by an approved State program as determined by the Secretary of the Interior or directly by the Secretary of the Interior in States with approved programs.
"Lowest floor"
means the lowest floor of the lowest enclosed area of a structure.
"Manufactured home"
means a structure, transportable in one or more sections, that is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term "manufactured home" does not include a "recreational vehicle."
"Manufactured home park or subdivision"
means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for rent or sale.
"Market value"
means the market value of properties subject to this chapter as determined in accordance with the criteria developed by the Floodplain Administrator.
"Mean sea level"
means the mean sea level elevation referenced in the Flood Insurance Rate Map for the City.
"New construction"
means structures for which the "start of construction" commenced on or after the adoption of the ordinance codified in this chapter and includes any subsequent improvements to such structures.
"New manufactured home park or subdivision"
means 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 on or after the adoption of the ordinance codified in this chapter.
"Recreational vehicle"
means a vehicle that is built on a single chassis, 400 square feet or less in length when measured at the largest horizontal projection, designed to be self propelled or permanently towable by a light duty truck, and designed primarily for use as a temporary living quarters for recreational, camping, travel, or seasonal use and as a permanent dwelling.
"Regulatory floodway"
means 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 foot.
"Special flood hazard area"
means the land in the floodplain within a community subject to a one percent or greater chance of flooding in any given year.
"Start of construction"
includes substantial improvement and other proposed new development and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within 180 days from the date of the permit. The actual start means either 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 manufacture 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. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.
"Structure"
means a walled and roofed building that is principally above ground, a gas or liquid storage tank, or a manufactured home.
"Substantial damage"
means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50% of the market value of the structure before the damage occurred.
"Substantial improvement"
means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 50% of the market value of the structure before the "start of construction" of the improvement, or any reconstruction, repair, rehabilitation, or addition to any structure that has incurred "substantial damage," regardless of the amount of actual repair work performed. The term does not include either:
1. 
Any project for improvement of a structure to correct existing violations of State or local health, sanitary, or safety code specifications that have been identified by the local code enforcement official and are the minimum necessary to assure safe living conditions.
2. 
Any alteration of a "historic structure," unless such alteration would cause the structure to lose its designation as a "historic structure."
"Watercourse"
means a lake, river, creek, stream, wash, arroyo, channel, or other topographical feature on or over which waters flow at least periodically; including, but not limited to, designated areas in which substantial flood damage may occur.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
This chapter shall apply to all special flood hazard areas within the City of Norwalk as identified by the Federal Emergency Management Agency in the Flood Insurance Study for Los Angeles County, California and Incorporated Areas dated September 26, 2008 and the accompanying Flood Insurance Rate Maps dated September 26, 2008. The special flood hazard areas so identified, are hereby adopted by reference and declared to be a part of this chapter and constitute the minimum applicable area of this chapter and may be supplemented by studies for other areas that allow implementation of this chapter and that are recommended to the City Council by the Floodplain Administrator. The Flood Insurance Study and Flood Insurance Rate Map shall be kept on file at the office of the City Clerk, located at 12700 Norwalk Boulevard, Norwalk, California.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with this chapter and other applicable regulations. Violation of the requirements of this chapter or any conditions and safeguards imposed pursuant to this chapter shall constitute a misdemeanor. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this chapter is presumed to be in violation until such time as that documentation is provided. Nothing herein shall prevent the City from taking such lawful action as is necessary to prevent or remedy any violation of this chapter.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restriction shall prevail.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
In the interpretation and application of this chapter, all provisions shall be considered as minimum requirements; liberally construed in favor of the City; and deemed neither to limit nor repeal any other powers granted under State statutes.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
The degree of flood protection required by this chapter 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 chapter 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 chapter shall not make the City or any officer or employee thereof, the State of California, or the Federal Insurance Administration, Federal Emergency Management Agency liable for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
A development permit shall be obtained for all proposed construction or other development, including the placement of manufactured homes, so that it may be determined whether such construction or other development is within a special flood hazard area.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
No development within a special flood hazard area shall be allowed unless the applicant has obtained all necessary permits from those governmental agencies whose approval is required by Federal, State, or local law, including, but not limited to, Section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. Section 1344.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
The duties and responsibilities of the Floodplain Administrator shall include, but not be limited to the following:
A. 
Permit Review. The Floodplain Administrator shall review all development permit applications to determine whether the requirements of this chapter have been satisfied, including determination of substantial improvement and substantial damage of existing structures; all other State and Federal permits have been obtained; and the site is reasonably safe from flooding.
B. 
Review and Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 15.48.030, the Floodplain Administrator shall obtain, review, and reasonably utilize any base flood elevation and regulatory floodway data available from other Federal or State agencies, or other sources, for the purpose of ensuring compliance with this chapter.
C. 
Notification of Alteration or Relocation of Watercourses. The Floodplain Administrator shall notify adjacent communities and the California Department of Water Resources prior to the alteration or relocation of any watercourse within the City, and shall provide the Federal Emergency Management Agency with evidence of such notification and assure that the flood carrying capacity within the altered or relocated portion of said watercourse is maintained.
D. 
Notification of Boundary Changes. The Floodplain Administrator shall promptly notify the Federal Emergency Management Agency in writing whenever the boundaries of the City have been modified by annexation or other means. Such notice shall include a copy of a map of the community clearly delineating the new corporate limits.
E. 
Records and Certifications. The Floodplain Administrator shall keep, maintain, and make available for public inspection all base flood elevation and certifications submitted to the City pursuant to this chapter.
F. 
Map Determinations. The Floodplain Administrator may determine the exact boundaries of special flood hazard areas wherever a mapped boundary conflicts with actual field conditions.
G. 
Regulatory Floodway Designation. The Floodplain Administrator shall select and designate a portion of the floodplain to be preserved as the City's regulatory floodway for the storage and dissipation of floodwaters. The regulatory floodway designated by the Floodplain Administrator shall be sufficient to carry the waters of the base flood without elevating the water surface area of that flood more than one foot at any point.
H. 
Determination of Market Value. The Floodplain Administrator shall develop criteria for determining the market value of properties subject to this chapter for the purpose of enforcing its requirements.
I. 
Base Flood Elevation Changes Due to Physical Alterations. Within six months of information becoming available or project completion, whichever comes first, the floodplain administrator shall submit or assure that the permit applicant submits technical or scientific data to FEMA for a Letter of Map Revision (LOMR). All LOMRs for flood control projects are approved prior to the issuance of building permits. Building Permits must not be issued based on Conditional Letters of Map Revision (CLOMRs). Approved CLOMRs allow construction of the proposed flood control project and land preparation as specified in the "start of construction" definition. Such submissions are necessary so that upon confirmation of those physical changes affecting flooding conditions, risk premium rates and floodplain management requirements are based on current data.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
All proposed development within a special flood hazard area must comply with the construction standards set forth in this section.
A. 
All building sites must be made reasonably safe from flooding.
B. 
All new construction and substantial improvements of structures, including manufactured homes, 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; and constructed with materials and utility equipment resistant to flood damage and using methods and practices that minimize flood damage.
C. 
Electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities included in any new construction of or substantial improvements to any structure, including manufactured homes, shall be designed and/or located so as to prevent water from entering or accumulating within the components during flooding.
D. 
All fully enclosed areas below the lowest floor of any new construction or substantial improvement that is useable solely for the parking of vehicles, building access, or storage in an area other than a basement, and which is 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 include a minimum of two openings having a total net area of not less than one square inch for every square inch of enclosed area subject to flooding. For these purposes, the openings shall be no higher than one foot above grade and may be equipped with screens, louvers, valves, or other coverings or devices only if they allow for the automatic entry and exit of floodwaters.
E. 
Encroachments, including, but not limited to, fill, new construction, substantial improvements, and other development, are prohibited within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practices that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharge.
F. 
No construction or substantial improvement shall alter or relocate any watercourse in any manner that decreases the flood carrying capacity of such watercourse.
G. 
The lowest floor (including the basement) of all new construction and substantial improvements of residential structures shall be elevated to or above the base flood level.
H. 
The lowest floor (including the basement) of all new construction and substantial improvements of non-residential structures shall either be elevated to or above the base flood level, or designed so that any part of the structure or attendant utility and/or sanitary facilities below the base flood level the structure are watertight, with walls substantially impermeable to the passage of water, and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. The applicant shall provide the Floodplain Administrator with the elevation in relation to mean sea level to which the structure has been waterproofed.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
In addition to all other applicable requirements, manufactured homes in a special flood hazard area shall also meet or exceed the standards set forth in this section.
A. 
All manufactured homes in a special flood hazard area shall be installed using methods and practices that minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement during flood conditions. Methods of anchoring a manufactured home may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable State and local anchoring requirements for resisting wind forces.
B. 
All manufactured homes placed or substantially improved in a special flood hazard area and located in a new manufactured home park, outside of a manufactured home park or subdivision, in an expansion of an existing manufactured home park or subdivision, or in an existing manufactured home park or subdivision in which a manufactured home has incurred substantial damage as a result of flooding, shall be elevated on a permanent foundation such that the lowest floor is at or above the base flood elevation and shall be securely anchored to a foundation system so as to resist flotation, collapse, and lateral movement during flood conditions.
C. 
All manufactured homes to be placed or substantially improved in an existing manufactured home park or subdivision in a special flood hazard area and not subject to subsection (B) of this section shall either be elevated so that the lowest floor of the manufactured home is at or above the base flood elevation, or have its chassis supported by reinforced piers or other foundational elements of equivalent or greater strength, that are at least 36 inches in height above grade and securely anchored to a foundation system so as to resist flotation, collapse, and lateral movement during flood conditions.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
All recreational vehicles located in a special flood hazard area require a permit in accordance with this chapter and must meet the anchoring requirements applicable to manufactured homes set forth in Section 15.48.120(B) unless such vehicle is either left on site for no more than 180 consecutive days or fully licensed and ready for highway use. For this purpose, a recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site on by quick disconnect type utilities and security devices, and has no permanently attached additions.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
A. 
All subdivisions, manufactured home parks, or any other proposed new development in a special flood hazard area shall be consistent with the need to minimize flood damage and shall provide adequate drainage to reduce exposure to flood hazards.
B. 
All new subdivision proposals and other proposed developments (including proposals for manufactured home parks) in a special flood hazard area that include 50 or more lots and/or cover five or more acres, must include base flood elevation data.
C. 
All public utilities and facilities such as sewer, gas, electrical, and water systems included in any proposal for a subdivision, manufactured home park, or any other proposed new development in a special flood hazard area shall be located and constructed to minimize or eliminate flood damage.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
A. 
All new and replacement water supply and sanitary sewage systems in a special flood hazard shall be designed to minimize or eliminate both infiltration of flood waters into the systems and discharge from the systems into flood waters.
B. 
On-site waste disposal systems in special flood hazard areas shall be located to avoid impairment to them, or contamination from them during flooding.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)
A. 
Variances from the requirements of this chapter may only be granted pursuant to the terms of this section and shall not relieve any person or property owner of any duty to comply with any other applicable provision of law.
B. 
Notwithstanding any other provision of this chapter, a variance shall not be granted for development in or encroachment onto any designated regulatory floodway if any increase in flood levels during the base flood would occur as a result.
C. 
Variances from the requirements of this chapter may be granted for new construction or substantial improvements to be erected on a lot of one-half acre or less in size that is contiguous to and surrounded by lots with existing structures constructed below the base flood level. Such a variance shall be granted if the following findings are made:
1. 
There is good and sufficient cause for granting the variance;
2. 
Failure to grant the variance would result in exceptional hardship to the applicant;
3. 
The variance is the minimum deviation from the requirements of this chapter that is necessary to afford relief considering the flood hazard; and
4. 
Granting the variance will not result in increased flood heights, additional threats to public safety, or extraordinary public expense; create a nuisance; cause a fraud on or victimization of the public; or conflict with existing local laws or ordinances.
D. 
Variances shall be granted for the repair or rehabilitation of historic structures only upon a finding that the proposed repair or rehabilitation will not preclude the structure's continued designation as a historic structure and is the minimum deviation from the requirements of this chapter that is necessary to preserve the historic character and design of the structure.
E. 
The Floodplain Administrator shall notify all applicants for a variance in writing that construction below the base flood level increases risks to life and property and that the issuance of a variance to construct a structure below the base flood level will result in increases in flood insurance premiums as high as $25 for every $100 of insurance coverage.
(Ord. 08-1613 § 2; Ord. 21-1722 § 2)