CHAPTER 6
FLOODPLAIN MANAGEMENT
Sections:
§ 8600 Statutory Authorization.
§ 8600.05 Statement of Purpose.
§ 8600.25 Provisions for Flood Hazard Reduction.
§ 8600.30 Regulatory Floodway.
8600 Statutory Authorization.
Government Code Sections 65302, 65560, and 65800 confer upon the City of Carson (sometimes, “City”) the legal authority to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. (Ord. 06-1351, § 1; Ord. 21-2102, § 2)
8600.05 Statement of Purpose.
It is the purpose of this Chapter 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:
A. Protect human life and health;
B. Minimize expenditure of public money for costly flood control projects;
C. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;
D. Minimize prolonged business interruptions;
E. Minimize damage to public facilities and utilities such as water and gas mains; electric, telephone and sewer lines; and streets and bridges located in areas of special flood hazard;
F. Help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future blighted areas caused by flood damage;
G. Ensure that potential buyers are notified that property is in an area of special flood hazard; and
H. Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions. (Ord. 06-1351, § 1; Ord. 21-2102, § 2)
8600.10 Definitions.
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.
A. “Area of special flood hazard” means the land in the floodplain within a community subject to a one (1) percent or greater chance of flooding in any given year.
B. “Base flood” means a flood which has a one (1) percent chance of being equaled or exceeded in any given year (also called the “one-hundred-year flood” or “100-year flood”). “Base flood” is the term used throughout this Chapter.
C. Building – see “Structure.”
D. “Development” means any manmade 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.
E. “Flood” or “flooding” means:
1. A general and temporary condition of partial or complete inundation of normally dry land areas from: the overflow of inland or tidal waters; the unusual and rapid accumulation or runoff of surface waters from any source; or mudslides (i.e., 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.
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.
F. “Floodplain” or “flood-prone area” means any land area susceptible to being inundated by water from any source – see “Flooding.”
G. “Floodplain Administrator” is the individual appointed to administer and enforce the floodplain management regulations.
H. “Floodplain management” means the operation of an overall program of corrective and preventive measures for reducing flood damage and preserving and enhancing, where possible, natural resources in the floodplain, including but not limited to emergency preparedness plans, flood control works, floodplain management regulations, and open space plans.
I. “Floodplain management regulations” means this Chapter and other zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as grading and erosion control) and other application of police power which control development in flood-prone areas. This term describes Federal, State or local regulations in any combination thereof which provide standards for preventing and reducing flood loss and damage.
J. “Governing body” is the local governing unit, i.e., county or municipality, that is empowered to adopt and implement regulations to provide for the public health, safety and general welfare of its citizenry.
K. “Historic structure” means any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the Department of 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 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 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.
L. “Manufactured home” means 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 attached to the required utilities. The term “manufactured home” does not include a recreational vehicle.
M. “Manufactured home park or subdivision” means a parcel (or contiguous parcels) of land divided into two (2) or more manufactured home lots for rent or sale.
N. “New construction,” for floodplain management purposes, means structures for which the start of construction commenced on or after the effective date of floodplain management regulations adopted by this community, and includes any subsequent improvements to such structures.
O. “One-hundred-year flood” or “100-year flood” – see “base flood.”
P. “Recreational vehicle” means a vehicle which is:
1. Built on a single chassis;
2. Four hundred (400) square feet or less when measured at the largest horizontal projection;
3. Designed to be self-propelled or permanently towable by a light-duty truck; and
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.
Q. “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 one hundred eighty (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 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. 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.
R. “Structure” means a walled and roofed building that is principally above ground; this includes a gas or liquid storage tank or a manufactured home.
S. “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 fifty (50) percent of the market value of the structure before the damage occurred.
T. “Substantial improvement” means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds fifty (50) percent of the market value of the structure before the start of construction of the improvement. This term includes structures which have incurred substantial damage, regardless of the actual repair work performed. The term does not, however, include either:
1. Any project for improvement of a structure to correct existing violations of State or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or
2. Any alteration of a historic structure; provided, that the alteration will not preclude the structure’s continued designation as a historic structure. (Ord. 06-1351, § 1; Ord. 21-2102, § 2)
8600.15 General Provisions.
1. Lands to Which This Chapter Applies. This Chapter shall apply to all areas identified as flood-prone within the jurisdiction of City of Carson.
2. Basis for Establishing Flood-Prone Areas. The Floodplain Administrator shall obtain, review, and reasonably utilize any base flood data available from other Federal or State agencies or other source to identify flood-prone areas within the jurisdiction of City of Carson. This data will be on file at the City Hall, City of Carson, City Clerk Office, 701 E. Carson Street, Carson, CA 90745. No construction will be permitted in areas of special flood hazard in the City of Carson as identified in the “Flood Insurance Study (FIS) for the County of Los Angeles” dated July 6, 1998, with accompanying Flood Insurance Rate Maps (FIRMs) and Flood Boundary and Floodway Maps (FBFMs) and all subsequent amendments thereto, which are hereby adopted by this reference and declared to be a part of this Chapter. An area of special flood hazard is an area in the floodplain subject to a one (1) percent or greater chance of flooding in any given year. It is shown on the most recent FIRM for the City of Carson as Zone A, AO, A1–A30, AE, A99, or AH.
3. Compliance. No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this Chapter and other applicable regulations. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Nothing herein shall prevent the City of Carson from taking such lawful action as is necessary to prevent or remedy any violation.
4. Abrogation and Greater Restrictions. 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 restrictions shall prevail.
5. Interpretation. In the interpretation and application of this Chapter, all provisions shall be:
A. Considered as minimum requirements;
B. Liberally construed in favor of the governing body; and
C. Deemed neither to limit nor repeal any other powers granted under State statutes.
6. Warning and Disclaimer of Liability. 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 manmade or natural causes. This Chapter does not imply that land outside the areas of special flood hazard or uses permitted within such areas will be free from flooding or flood damages. This Chapter shall not create liability on the part of City of Carson, any officer or employee thereof, the State of California, or the Federal Insurance Administration, Federal Emergency Management Agency, for any flood damages that result from reliance on this Chapter or any administrative decision lawfully made hereunder. (Ord. 06-1351, § 1; Ord. 08-1412, § 1; Ord. 21-2102, § 2)
8600.20 Administration.
1. Establishment of Development Permit. A development permit shall be obtained for all proposed construction or other development in the community, including the placement of manufactured homes, so that it may be determined whether such construction or other development is within flood-prone areas.
2. Designation of the Floodplain Administrator. The City Engineer is hereby appointed to administer, implement, and enforce this Chapter by granting or denying development permits in accord with its provisions.
3. Duties and Responsibilities of the Floodplain Administrator. The duties and responsibilities of the Floodplain Administrator shall include, but not be limited to, the following:
A. Permit Review. Review all development permit applications to determine that:
1. Permit requirements of this Chapter have been satisfied;
2. All other required State and Federal permits have been obtained; and
3. The site is reasonably safe from flooding.
B. Review and Use of Any Other Base Flood Data. The Floodplain Administrator shall obtain, review, and reasonably utilize any base flood data available from other Federal or State agency or other source.
C. Alteration or Relocation of a Watercourse.
1. Notify adjacent communities and the California Department of Water Resources prior to alteration or relocation;
2. Submit evidence of such notification to the Federal Emergency Management Agency; and
3. Assure that the flood carrying capacity within the altered or relocated portion of said watercourse is maintained.
D. Changes in Corporate Boundaries. Notify FEMA in writing whenever the City’s corporate boundaries have been modified by annexation or other means and include a copy of a map of the City of Carson clearly delineating the new corporate limits.
E. Base Flood Elevation Data. Where base flood elevation data are utilized, the following actions must be taken:
1. Obtain the elevation (in relation to mean sea level) of the lowest floor (including basement) of all new and substantially improved structures;
2. If the structure has been floodproofed in accordance with 44 C.F.R. Section 60.3(c)(3)(ii), obtain the elevation (in relation to mean sea level) to which the structure was floodproofed; and
3. Maintain a record of all such information.
F. Federal Insurance Administrator and Notice of Final Flood Elevations – No Regulatory Floodway Identified. When the Federal Insurance Administrator has provided a notice of final flood elevations for one or more special flood hazard areas on the City’s FIRM and, if appropriate, has designated other special flood hazard areas without base flood elevations on the City’s FIRM, but has not identified a regulatory floodway or coastal high hazard area, the City of Carson shall:
1. Require that all new construction and substantial improvements of residential structures within Zones A1–A30, AE and AH on the City of Carson’s FIRM have the lowest floor (including basement) elevated to or above the base flood level, unless the City is granted an exception by the Federal Insurance Administrator for the allowance of basements in accordance with 44 C.F.R. Section 60.6(b) or (c);
2. Require that all new construction and substantial improvements of nonresidential structures within Zones A1–A30, AE and AH on the City’s FIRM (i) have the lowest floor (including basement) elevated to or above the base flood level or, (ii) together with attendant utility and sanitary facilities, be designed so that below the base flood 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;
3. Require, for all new construction and substantial improvements, that fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which 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;
4. Require that manufactured homes that are placed or substantially improved within Zones A1–A30, AH, and AE on the City’s FIRM on sites:
(i) Outside of a manufactured home park or subdivision,
(ii) In a new manufactured home park or subdivision,
(iii) In an expansion to an existing manufactured home park or subdivision, or
(iv) In an existing manufactured home park or subdivision on which a manufactured home has incurred substantial damage as the result of a flood, be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement;
5. Require that manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1–A30, AH, and AE on the City’s FIRM that are not subject to the provisions of 44 C.F.R. Section 60.6(c)(6) be elevated so that either:
(i) The lowest floor of the manufactured home is at or above the base flood elevation, or
(ii) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six (36) inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement; and
6. Require that recreational vehicles placed on sites within Zones A1–A30, AH, and AE on the City’s FIRM either:
(i) Be on the site for fewer than one hundred eighty (180) consecutive days,
(ii) Be fully licensed and ready for highway use, or
(iii) Meet the permit requirements of 44 C.F.R. Section 60.6(b)(1) and the elevation and anchoring requirements for manufactured homes in 44 C.F.R. Section 60.6(c)(6).
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.
G. Federal Insurance Administrator and Notice of Final Flood Elevations – Regulatory Floodway Designation. When the Federal Insurance Administrator has provided a notice of final base flood elevations within Zones A1–A30 and/or AE on the City’s FIRM and, if appropriate, has designated AO zones, AH zones, A99 zones, and A zones on the City’s FIRM, and has provided data from which the City shall designate its regulatory floodway, the City shall:
1. Select and adopt a regulatory floodway based on the principle that the area chosen for the regulatory floodway must be designed to carry the waters of the base flood, without increasing the water surface elevation of that flood more than one (1) foot at any point; and
2. Prohibit encroachments, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the City during the occurrence of the base flood discharge. (Ord. 06-1351, § 1; Ord. 21-2102, § 2)
8600.25 Provisions for Flood Hazard Reduction.
1. Standards of Construction. If a proposed building site is in a flood-prone area, all new construction and substantial improvements, including manufactured homes, shall:
A. 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. Be constructed:
1. With materials and utility equipment resistant to flood damage;
2. Using methods and practices that minimize flood damage;
3. 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.
2. Standards for Subdivisions or Other Proposed New Development. If a subdivision proposal or other proposed new development, including manufactured home parks or subdivisions, is in a flood-prone area, any such proposals shall be reviewed to assure that:
A. All such proposals are consistent with the need to minimize flood damage within the flood-prone area;
B. All public utilities and facilities such as sewer, gas, electrical, and water systems are located and constructed to minimize or eliminate flood damage;
C. Adequate drainage is provided to reduce exposure to flood hazards; and
D. All such proposals include base flood elevation data.
3. Standards for Utilities.
A. All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate:
1. Infiltration of flood waters into the systems, and
2. Discharge from the systems into flood waters.
B. On-site waste disposal systems shall be located to avoid impairment to them, or contamination from them during flooding. (Ord. 06-1351, § 1; Ord. 21-2102, § 2)
8600.30 Regulatory Floodway.
Until a regulatory floodway is adopted, no new construction, substantial development, or other development (including fill) shall be permitted within Zone A unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other development, will not increase the water surface elevation of the base flood more than one (1) foot at any point within lands under the jurisdiction of the City of Carson. (Ord. 21-2102, § 2)