Chico Municipal Code Ch. 16R.37 Floodplain Standards (CA)

Section:

16R.37.010 General provisions.

The floodplain standards set forth in this chapter shall constitute the floodplain standards of the city and shall apply to all development occurring within a special flood hazard area of the city in accordance with the provisions of Section 16.37.010 of this code.

(Res. No. 124 96-97)

16R.37.020 Findings.

In accordance with the provisions of Section 17958.5 of the Health and Safety Code, the city council finds that all of the floodplain standards set forth in this chapter which add to or are more restrictive than the standards set forth in Section 16R.02.010 of this code are required by local topographical conditions. In particular, the city council finds that the floodplain standards set forth in this chapter are applicable to buildings, structures, manufactured homes, underground electrical and plumbing subject to damage, earth movement activities, and other development or subdivisions that propose new such buildings, on property located within a special flood hazard area or area of moderate flood hazard that such property is situated at an elevation below the base flood level, that because such property is situated below the base flood level, it is subject to periodic inundation by flood waters, and that the flood standards set forth in this chapter are necessary in order to ensure that development is properly elevated, floodproofed and otherwise protected from flood damage, and in order to prevent such development from creating obstructions which cause or contribute to an increase in flood heights and velocities.

Required findings. Under California Government Code section 65962, if a proposed project is located within a flood hazard zone, the City may not approve 1) a Development Agreement; 2) a discretionary permit or other discretionary entitlement that would result in the construction of a new building or construction that would result in an increase in allowed occupancy for an existing building; 3) a ministerial permit that would result in the construction of a new residence; 4) a tentative map, or a parcel map for which a tentative map was not required; unless the City finds, based on substantial evidence in the record, one of the following:

A. The facilities of the State Plan of Flood Control or other flood management facilities protect the project to the urban level of flood protection in urban or urbanizing areas; or, the national Federal Emergency Management Agency (FEMA) standard of flood protection in non-urbanized areas.

B. The City has imposed conditions on the permit or entitlement that will protect the project to the urban level of flood protection in urban and urbanizing area; or, the national Federal Emergency Management Agency (FEMA) standard of flood protection in non-urbanized areas.

C. If the property is intended to be protected by project levees, the City has made adequate progress on the construction of the flood protection system which will result in flood protection equal to or greater than the urban level of flood protection in urban and urbanizing areas; or, the national Federal Emergency Management Agency (FEMA) standard of flood protection in non-urbanized areas the urban level of flood protection shall be achieved by 2025.

D. The City has imposed conditions on the permit or entitlement that will protect the project to the National FEMA Standard of Flood Protection in an urban or urbanizing area where the project is subject to shallow flooding or local drainage.

(Res. No. 124 96-97, Res. No. 139-07, Res. 60-25)

16R.37.025 Compliance.

No new construction, or substantial improvement of a structure or other development that would require a building or grading permit pursuant to the applicable provisions of the California Building Code as adopted and modified in Title 9 of the Code shall take place in an area of special flood hazard without full compliance with the terms of this chapter and other applicable flood control regulations. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute an infraction. Nothing herein shall prevent the City from taking such lawful action as is necessary to prevent or remedy any violation.

(Res. 60-25)

16R.37.030 Definitions.

The definitions set forth in Chapter 16.35 of this code and the following additional definitions set forth in this section shall govern the construction of the words and phrases contained in the floodplain standards adopted in this chapter.

A. Basement. The term “basement” means any area of the building having its floor subgrade on all sides.

B. Encroachment. The term “encroachment” means the advancement or infringement of uses, plant growth, fill, excavation, buildings, permanent structures or development into a floodplain which may impede or alter the flow capacity of a floodplain.

C. Existing Manufactured Home Park. The term “existing manufactured home park” means a manufactured home park 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 standards adopted by this chapter.

D. Expansion to an Existing Manufactured Home Park. The term “expansion to an existing manufactured home park” means 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).

E. Floodproofing. The term “floodproofing” means any combination of structural and nonstructural additions, changes or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures, and their contents.

F. Highest Adjacent Grade. The term “highest adjacent grade” means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

G. Lowest Floor. The term “lowest floor” means the lowest floor of the lowest enclosed area, including a basement. An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this chapter.

H. Manufactured Home. The term “manufactured home” means a structure, transportable in one 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.”

I. New Construction. The term “new construction” means structures for which the “start of construction” commenced on or after the effective date of floodplain standards adopted by this chapter, and includes any subsequent improvements to such structures.

J. New Manufactured Home Park. The term “new manufactured home park” means a manufactured home park 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 effective date of floodplain standards adopted by this chapter.

K. Obstruction. The term “obstruction” includes, but is not limited to, any dam, wall, wharf, embankment, levee, dike, pile, abutment, protection, excavation, channelization, bridge, conduit, culvert, building, wire, fence, rock, gravel, refuse, fill, structure, vegetation or other material in, along, across or projecting into any watercourse which may alter, impede, retard or change the direction and/or velocity of the flow of water, or due to its location, its propensity to snare or collect debris carried by the flow of water, or its likelihood of being carried downstream.

L. Recreational Vehicle. The term “recreational vehicle” means a vehicle which is built on a single chassis; 400 square feet or less when measured at the largest horizontal projection; designed to be self-propelled or permanently towable by a light-duty truck; and designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

M. Start of Construction. The term “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 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.

N. Substantial Damage. The term “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 percent of the market value of the structure before the damage occurred.

O. Substantial Improvement. The term “substantial improvement” means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 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.

P. Water Surface Elevation. The term “water surface elevation” means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929, (or other datum, where specified) of floods of various magnitudes and frequencies in the floodplains of coastal and riverine areas.

(Res. No. 124 96-97)

16R.37.040 Standards of construction - Anchoring.

All new construction and substantial improvements shall be adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. All manufactured homes shall meet the anchoring standards of Section 16R.37.080.

(Res. No. 124 96-97)

16R.37.050 Standards of construction - Construction materials and methods.

All new construction and substantial improvement shall be constructed:

A. With materials and utility equipment resistant to flood damage;

B. Using methods and practices that minimize flood damage;

C. 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; and if

D. Within zones designated as AH or AO on the approved floodplain maps on file in the office of the building division, so that there are adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.

(Res. No. 124 96-97)

16R.37.060 Standards of construction - Elevation and floodproofing.

A. Residential construction, new or substantial improvement, shall have the lowest floor, including basement:

Within a zone designated as AO on the approved floodplain maps on file in the office of the building division, elevated above the highest adjacent grade to a height equal to or exceeding one foot above the depth number specified in feet on the flood insurance rate map, or elevated at least two feet above the highest adjacent grade if no depth number is specified.
Within a zone designated as A on the approved floodplain maps on file in the office of the building division, elevated to at least one foot above the base flood elevation, as determined by the building official.
In all other zones, elevated to at least one foot above the base flood elevation.

Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a licensed architect, licensed land surveyor, or registered civil engineer, and verified by the building official to be properly elevated.

B. Nonresidential construction, new or substantial improvement, shall either be elevated to conform with Section 16R.37.060-A of this chapter or together with attendant utility and sanitary facilities:

Be floodproofed below the elevation required by Section 16R.37.060-A of this chapter so that the structure is watertight with walls substantially impermeable to the passage of water;
Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
Be certified by a licensed architect or registered civil engineer that the standards of this section have been satisfied. Such certification shall be provided to the building official.

C. All new construction and substantial improvement with fully enclosed areas below the lowest floor, excluding basements, that are usable solely for parking of vehicles, building access or storage, 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 floodwater. Designs for meeting this requirement must exceed the following minimum criteria:

Be certified by a licensed architect, licensed land surveyor, or registered civil engineer; or
Have a minimum of two openings having a total net area of not less than one square inch for every foot of enclosed area subject to flooding. The bottom of all openings shall be no higher than one 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 floodwater.

D. Manufactured homes shall also meet the standards in Section 16R.37.080 of this chapter.

(Res. No. 124 96-97, Res. 60-25)

16R.37.070 Standards for utilities.

A. All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate:

Infiltration of flood waters into the system; and
Discharge from the systems into flood waters.

B. Onsite waste disposal systems shall be located to avoid impairment to them, or contamination from them during flooding.

(Res. No. 124 96-97)

16R.37.080 Standards for manufactured homes.

A. All manufactured homes that are placed or substantially improved, within Zones A1-30, AH, and AE on the approved floodplain maps on file in the office of the building division, on sites located:

1. outside of a manufactured home park,
1. in a new manufactured home park,
1. in an expansion to an existing manufactured home park, or

in an existing manufactured home park on a site upon which a manufactured home has incurred “substantial damage” as the result of a flood, shall 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.

B. All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park within Zones A1-30, AH, or AE on the approved floodplain maps on file in the office of the building division that are not subject to the provisions of Section 16R.37.080-A of this chapter will be elevated so that either the:

Lowest floor of the manufactured home is at or at least one foot above the base flood elevation, or
Manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
Mechanical equipment including condensing units and mechanical ducting shall be elevated and protected from potential flooding.

(Res. No. 124 96-97, Res. 60-25)

16R.37.090 Standards for recreational vehicles.

All recreational vehicles placed on sites within Zones A1-30, AH, and AE on the approved floodplain maps on file in the office of the building division will either:

A. Be on the site for fewer than 180 consecutive days,

B. Be fully licensed and ready for highway use – 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

C. Meet the elevation and anchoring requirements for manufactured homes in Sections 16R.37.060 and 16R.37.080 of this chapter.

(Res. No. 124 96-97)

16R.37.095 Standards for subdivisions.

A. All preliminary subdivision proposals shall identify the flood hazard area and the base flood elevation. The documents shall clearly indicate the Lowest Adjacent Grade and the Highest Adjacent Grade prior to the alteration of the existing topography before grading (cut or fill).

B. All final subdivision plans will provide the lowest floor elevation of proposed structures and pads. If the site is filled above the base flood, the final pad elevation shall be certified by a registered professional engineer and provided to the Floodplain Administrator and a Letter of Map Revision will be submitted to FEMA.

C. All subdivision proposals shall be consistent with the need to minimize flood damage.

D. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.

E. All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.

(Res. 60-25)

16R.37.100 Floodways.

The approved floodplain maps on file in the office of the building division may designate certain flood hazardous areas as floodways. Such floodways are extremely hazardous due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential. Within such floodways, the following provisions apply:

A. Prohibit encroachments including fill, new construction, substantial improvement, and other new development unless certification by a licensed architect or registered civil engineer is provided demonstrating that such encroachments shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge.

B. If subpart A of this section is satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of this chapter.

(Res. No. 124 96-97)