Marin County Municipal Code Ch. 23.09 Floodplain Management

Prior ordinance history: Ords. 2690, 2710, 2971 and 2978.

The Legislature of the state of California has in Government Code Sections 65302, 65560 and 65800 conferred upon local governmental units authority to adopt regulations designed to promote the public health, safety and general welfare of its citizenry. Therefore, the board of supervisors of the county of Marin does adopt the following floodplain management regulations.

(Ord. 3293 § 1, 1999)

(1) The flood hazard areas of Marin County are subject to periodic inundation which results in loss of life and property, disruption of commerce and governmental services, health and safety hazards, extraordinary public expenditures for flood protection and relief, impairment of the tax base, all of which adversely affect the public health, safety and general welfare.

(2) These flood losses are caused by:

(A) The cumulative effect of obstructions in floodways and flood fringes, causing increased flood heights and erosive velocities;

(B) The occupancy of flood hazard areas by uses vulnerable to floods or hazardous to others, which are inadequately elevated or otherwise unprotected from flood damages.

(3) This chapter relies upon a reasonable process for analyzing the flood hazard affecting specific lands. The regulatory flood selected for this chapter is representative of large floods known to have occurred in this region and which are reasonably characteristic of what can be expected to occur on the particular watercourses, streams, creeks, rivers, bays and lakes subject to this chapter. It is in this general order of a flood which could be expected to occur on the average once every one hundred years or has a one percent chance of occurrence in any one year.

(4) The official flood identification map is adopted by reference and declared to be a part of this chapter and shall be that provided Marin County by the Federal Emergency Management Agency in its Flood Insurance Study dated March 1, 1982, and designated "Flood Insurance Rate Maps" (FIRM) and "Flood Boundary Floodway Maps," "Marin County, California, Unincorporated Area" dated May 5, 1997, and all subsequent amendments to and/or revisions of any of these. These maps delineate those areas determined to be subject to flooding from a flood which has a one percent chance of occurrence in any one year. Copies of said maps are on file with the department of public works, and may be inspected during regular county business hours.

(Ord. 3293 § 2, 1999)

(1) It is the purpose of this chapter to promote the public health, safety and general welfare and to minimize the losses described in this section by provisions designed to:

(A) Protect human life and health;

(B) Minimize expenditure of public money for 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 located in areas of special flood hazard;

(F) Help maintain a stable tax base by providing for the second use and development of areas of special flood hazard so as to minimize future flood blight areas;

(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.

(2) In order to accomplish its purposes, this chapter includes methods and provisions for:

(A) Restricting uses which are dangerous to health, safety and property due to water or erosion hazards, or which result in damaging increases in erosion or in flood heights or velocities;

(B) Requiring that uses vulnerable to flood, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

(C) Controlling the alteration of natural floodplains, stream channels, and natural protective barriers, which help accommodate or channel floodwaters;

(D) Controlling filling, grading, dredging and other development which may increase flood damage; and

(E) Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas.

(Ord. 3293 § 3, 1999)

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

(1) "Appeal" means a request for a review of the interpretation of floodplain administrator's interpretation of any provision of this chapter or a request for a variance.

(2) "Area of shallow flooding" means a designated AO, AH or VO zone on the flood insurance rate map (FIRM). The base flood depths range from one to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate; and velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

(3) Area of Special Flood Hazard. See "Special flood hazard area."

(4) "Base flood" means the flood having a one percent chance of being equaled or exceeded in any given year (also called the one hundred-year flood).

(5) "Basement" means any area of the building having its floor subgrade below ground level on all sides.

(6) "Breakaway walls" means any type of walls, whether solid or lattice, and whether constructed of concrete, masonry, wood, metal, plastic, or any other suitable building materials which are not part of the structural support of the building and which are so designed as to break away, under abnormally high tides or wave action, without damage to the structural integrity of the building on which they are used or any building to which they might be carried by floodwaters. A breakaway wall shall have a safe design loading resistance of not less than ten and no more than twenty pounds per square foot. Use of breakaway walls must be certified by a registered engineer or architect and shall meet the following conditions:

(A) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and

(B) The elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood.

(7) "Channel" is a natural or artificial water course, with a definite bed and banks to confine and conduct continuously or periodically flowing water. Channel flow thus is that water which is flowing within the limits of a defined channel.

(8) "Coastal high hazard area" means an area of special flood hazard extending from offshore to the inland limit of a primary frontal dune along an open coast and any other area subject to high velocity wave action from storms or seismic forces. It is an area subject to high velocity waters, including but not limited to coastal and tidal inundation or tsunamis. The area is designated on a FIRM as Zone VI-30, VE or V.

(9) "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 and storage of equipment or materials located within the area of special flood hazard.

(10) "Flood or flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from:

(A) The overflow of floodwaters;

(B) The unusual and rapid accumulation or runoff of surface waters from any source; and/or

(C) 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 unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in this definition.

(11) "Flood boundary-floodway map" means the official map on which the Federal Emergency Management Agency or the Federal Insurance Administration has delineated both the areas of flood hazard and the floodway.

(12) "Flood insurance rate map (FIRM)" means the official map on which the Federal Emergency Management Agency or the Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

(13) "Flood insurance study" means the official report provided by the Federal Emergency Management Agency or the Federal Insurance Administration that includes flood profiles, the FIRM, the flood boundary, floodway map, and the water surface elevation of the base flood.

(14) "Floodplain administrator" is the individual appointed to administer and enforce the floodplain management regulations.

(15) "Floodplain management" means the operation of an overall program of corrective and preventative measures for reducing flood damage, including but not limited to emergency preparedness plans, flood control works and floodplain management regulations.

(16) "Floodplain management regulations" means zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as floodplain ordinance, grading ordinance and erosion control ordinance) and other applications of police power. The term describes such state or local regulations in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.

(17) "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.

(18) "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. The floodway is delineated on the flood boundary-floodway map.

(19) "Functionally dependent use" means a use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does not include long-term storage or related manufacturing facilities.

(20) "Highest adjacent grade" means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

(21) "Lowest floor" means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood-resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement area 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 nonelevation design requirements of this chapter.

(22) "Historic structure" means 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 in 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 the State of California Inventory of Historic Places;

(D) Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified by an approved state program as determined by the Secretary of the Interior.

(23) "Manufactured home park or subdivision" means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for sale or rent.

(24) "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 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 consecutive days. It does not include a "recreational vehicle."

(25) "Mean sea level" means, for purposes of the National Flood Insurance Program, the National Geodetic Vertical Datum (NGVD) of 1929 or other datum, to which base flood elevations shown on a community's flood insurance rate map are referenced.

(26) "New construction" means for floodplain management purposes, structures for which the "start of construction" commenced on or after the effective date of the ordinance codified in Marin County Code Chapter 23.09.

(27) "One-hundred-year flood" or "100-year flood" means a flood which has a one percent annual probability of being equaled or exceeded. It is identical to the base flood, which will be the term used throughout this chapter.

(28) "Person" means an individual or his agent, firm, partnership, association or corporation, or agent of the aforementioned groups, or this state or its agencies or political subdivisions.

(29) "Planning commission" means the planning commission for the county of Marin.

(30) "Remedy a violation" means to bring the structure or other development into compliance with state or local floodplain management regulations, or, if this is not possible, to reduce the impacts of its noncompliance. Ways that impacts may be reduced include protecting the structure or other affected development from flood damages, implementing the enforcement provisions of the ordinance codified in this chapter or otherwise deterring future similar violations, or reducing federal financial exposure with regard to the structure or other development.

(31) "Recreational vehicle" means a vehicle which is:

(A) Built on a single chassis;

(B) No more than four hundred square feet when measured at the largest horizontal projection;

(C) Designed to be self-propelled or permanently towable by a light-duty truck; and

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

(32) "Riverine" means relating to, formed by, or resembling a river (including tributaries), stream, brook, etc.

(33) "Sand dunes" means naturally occurring accumulations of sand in ridges or mounds landward of the beach.

(34) "Special flood hazard area (SFHA)" means an area having special flood or flood-related erosion hazards and as shown on an FHBM or FIRM as Zone A, AO, A1-30, AE, A99, AH, VO, V1-V30, VE or V.

(35) "Start of construction" for this chapter only, includes substantial improvement, and means the date the building permit was issued; provided, the actual start of construction, repair, reconstruction, placement or other improvement was within one hundred eighty days of the permit date. 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. 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 structure. 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.

(36) "Structure" means a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home.

(37) "Substantial damage" means 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 of the value of the structure before the damage occurred.

(38) "Substantial improvement" means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds fifty percent of the market value of the structure either:

(A) Before the improvement or repair is started; or

(B) If the structure has been damaged and is being restored, before the damage occurred.

The term does not, however, include either:

(A) Any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assure safe living conditions; or

(B) Any alteration of a historic structure as defined in Section 23.09.030(22).

(39) "Variance" means a grant of relief from the requirements of Marin County Code Chapter 23.09 which permits construction in a manner that would otherwise be prohibited by Marin County Code Chapter 23.09.

(40) "Violation" means the failure of a structure or other development to be fully compliant with the community's floodplain management regulations. 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.

(41) "Watercourse" means a definite open channel with bed and banks within which water flows either perennially or intermittently including overflow channels contiguous to the main channel. A watercourse shall include both natural and manmade channels.

(Ord. 3293 § 4, 1999)

(A) Lands to Which This Chapter Applies. This chapter shall apply to all areas of special flood hazards within the jurisdiction of the county.

(B) Basis for Establishing the Areas of Special Flood Hazard. The areas of special flood hazard, identified by the Federal Emergency Management Agency or Federal Insurance Administration in a scientific and engineering report entitled "Flood Insurance Study for Marin County, California, unincorporated areas" dated November 19, 1986, and accompanying flood insurance rate maps and flood boundary and floodway maps, and all subsequent amendments to and/or revisions of any of these, are adopted by reference and declared to be a part of this chapter, as well as amendments thereto. This flood insurance study is on file at the Marin County department of public works. This flood insurance study is the minimum area of applicability of these rules and may be supplemented by studies for other areas which allow implementation of these rules and which are recommended to the board of supervisors by the floodplain administrator.

(C) No new structure, hereafter, shall be located, or existing structures substantially improved, without full compliance with the terms of this chapter and other applicable regulations.

(D) Abrogation and Greater Restrictions. It is not intended by this chapter to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this chapter conflicts or overlaps with other county code sections, resolutions and/or ordinances the most restrictive shall apply.

(E) Interpretation. Except as specifically provided herein, it is not intended by this chapter to repeal, abrogate, annul or in any way to impair or interfere with any existing provision of law or ordinance, or any rule, regulation or permit previously adopted or issued, or which shall be adopted or issued pursuant to law relating to the use of buildings or premises or relating to the erection, construction, establishment, moving, alteration or enlargement of any building improvement; nor is it is intended by this chapter to interfere with or abrogate or annul any easement, covenant or other agreement between parties; provided, however, that in cases where this chapter imposes a greater restriction upon the erection, construction, establishment, moving, alteration or enlargement of buildings or the use of any such building or premises than is imposed or required by such existing provisions of law or ordinance, or by such rules, regulations or permits, or by such easements, covenants or agreements, then in such case the provisions of this chapter shall control.

(F) Warning and Disclaimer of Liability. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on engineering and scientific considerations. Larger floods may occur or flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood hazards, or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the county or any officer or employee thereof or the Federal Insurance Administration, for any damages that result from reliance on this chapter or any administrative decision made lawfully thereunder.

(G) Severability. If any section, clause, provision or portion of this chapter is adjudged unconstitutional or invalid by a court of competent jurisdiction, the remainder of this chapter shall not be affected thereby.

(Ord. 3293 § 5, 1999)

The floodplain area within the jurisdiction of this chapter is as shown on the official flood identification map as defined in Section 23.09.011(4) of the Marin County code. Within this district all uses not meeting the standards of this chapter and those standards of the underlying zoning district shall be prohibited except that reasonable variances may be granted, as hereinafter provided.

(Ord. 3293 § 6, 1999)

(a) It is not the intent of this chapter to require permits other than those required under existing county permit procedures.

(b) All permit applications for proposed construction, substantial improvements or other development including but not limited to buildings or other structures, mining, dredging, paving, grading, excavation, drilling and placement of manufactured homes shall be reviewed by the department of public works to determine whether such construction or other development is proposed within flood prone areas and therefore subject to the provisions of this chapter. If it is determined that the proposed work is subject to this chapter, the following information will be required:

(1) Proposed elevation in relation to National Geodetic Vertical Datum (NGVD) of the lowest floor (including basement) of all structures; in Zone AO elevation of highest adjacent grade and proposed elevation of lowest floor of all structures;

(2) Proposed elevation in relation to NGVD to which any structure will be floodproofed;

(3) All appropriate certifications listed in subparagraph (6) of subsection (D) of this section;

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

(c) Designation of the Floodplain Administrator. The public works director is appointed to administer and implement this chapter.

(d) Duties and Responsibilities of the Floodplain Administrator. The duties and responsibilities of the floodplain administrator shall include, but not be limited to:

(1) Review all development permits to determine that the permit requirements of this chapter have been satisfied;

(2) The site is reasonably safe from flooding;

(3) The proposed development does not adversely affect the carrying capacity of areas where the base flood elevations have been determined but a floodway has not been designated. For purposes of this chapter, "adversely affects" means that the cumulative effect of the proposed development when combined with all other existing and anticipated development will increase the water surface elevation of the base flood more than one foot at any point.

(4) Use of Other Base Flood Data. When base flood elevation data has not been provided, the floodplain administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, in order to administer this chapter;

(5) Whenever a watercourse is to be altered or relocated:

(A) Notify adjacent communities and the California Department of Water Resources prior to such alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration,

(B) Require that the flood-carrying capacity of the altered or relocated portion of said watercourse is maintained;

(6) Obtain and maintain for public inspection and make available as needed for flood insurance policies:

(A) The certification required in Section 23.09.034(c)(1) (floor elevation),

(B) The certification required in Section 23.09.034(c)(2) (elevations in areas of shallow flooding),

(C) The certification required in Section 23.09.034(c)(3) (elevation or floodproofing nonresidential structures),

(D) The certification required in Section 23.09.034(c)(4) (wet floodproofing standard),

(E) The certification required in Section 23.09.036(b),

(F) The certification required in Section 23.09.038 (floodway encroachments),

(G) The information required in Section 23.09.039 (coastal construction standards); and

(7) Make interpretations where needed, as to the exact location of the boundaries of these areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual field conditions). The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in Section 23.09.040.

(8) Take action to remedy violations of this chapter as specified herein.

(Ord. 3293 § 7, 1999)

In all areas of special flood hazards, the following standards are required:

(a) Anchoring.

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

(2) All manufactured homes shall meet the anchoring standards of this chapter.

(b) Construction Materials and Methods.

(1) All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

(2) All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

(3) 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.

(4) Require within Zones AM, AO or VO, adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

(c) Elevation and Floodproofing.

(1) New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation. Nonresidential structures may meet the standards in subparagraph (3) of subsection (c) of this section. Upon completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered civil engineer, or licensed land surveyor. Such certification shall be provided to the floodplain administrator.

(2) New construction and substantial improvement of any structure in Zone AG or VO shall have the lowest floor, including basement, elevated above the highest adjacent grade and at least as high as the depth number specified in feet on the FIRM or at least two feet if no depth number is specified. Nonresidential structures may meet the standards in subparagraph (3) of subsection (c) of this section. Prior to occupancy of the structure, a registered civil engineer or licensed land surveyor shall certify that the elevation of the structure meets this standard and shall provide such certification to the floodplain administrator.

(3) Nonresidential construction shall either be elevated in conformance with subdivisions (1) or (2) of subsection (c) of this section, or, together with attendant utility and sanitary facilities:

(a) Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

(b) Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

(c) Be certified by a registered civil engineer or architect that the standards of this subsection are satisfied. Such certifications, shall be provided to the floodplain administrator.

(4) Require, for all new construction and substantial improvements, that 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 civil engineer or architect or meet or exceed the following minimum criteria:

(A) Either a minimum of two openings having a total net area of not less than one 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 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; or

(B) Be certified to comply with a local floodproofing standard approved by the Federal Insurance Administration.

(5) Manufactured homes shall also meet the standards in Section 23.09.037.

(Ord. 3293 § 8, 1999)

(a) All new and replacement water supply and sanitary sewage systems under the control of the county shall be designed to minimize or eliminate infiltration of floodwaters into the system or discharge from systems into floodwaters.

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

(Ord. 3293 § 9, 1999)

(a) All preliminary subdivision proposals shall identify the flood hazard area and the elevation of the base flood.

(b) All final subdivision plans will provide the 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 civil engineer or licensed land surveyor and provided to the floodplain administrator.

(c) All subdivision proposals shall be consistent with the need to minimize flood damage.

(d) All subdivision proposals shall have all utilities and facilities under the control of the county located and constructed to minimize flood damage.

(e) All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage.

(Ord. 3293 § 10, 1999)

All new and replacement manufactured homes and additions to manufactured homes shall:

(a) Be elevated so that the lowest floor is at or above the base flood elevation; and

(b) Be securely anchored to a permanent foundation system to resist flotation, collapse or lateral movement.

(Ord. 3293 § 11, 1999)

Located within areas of special flood hazard established in this chapter 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 apply:

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

(b) If Section 23.09.038 of this chapter is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this chapter.

(Ord. 3293 § 12, 1999)

Within coastal high hazard areas as defined in Section 23.09.030 of this chapter, the following standards shall apply:

(a) All new construction shall be located on the landward side of the reach of mean high tide.

(b) All new construction and substantial improvements shall be elevated on adequately anchored pilings or columns and securely anchored to such pilings or columns so that the lowest horizontal portion of the structural members of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood elevation.

(c) All new construction and substantial improvements shall have the space below the lowest floor free of obstructions or constructed with breakaway walls. Such temporarily enclosed space shall not be used for human habitation.

(d) Fill shall not be used for structural support of buildings.

(e) Manmade alteration of sand dunes which would increase potential flood damage is prohibited.

(f) The floodplain administrator shall obtain and maintain the following records:

(1) Certification by a registered engineer or architect that a proposed structure complies with this chapter;

(2) The elevation (in relation to mean sea level) of the bottom of the lowest structural member of the lowest floor (excluding pilings or columns) of all new and substantially improved structures, and whether such structures contain a basement.

(Ord. 3293 § 13, 1999)

(a) Conditions for Variances.

(1) Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places without regard to the procedures set forth in the remainder of this section.

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

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

(4) 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;

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

(5) Variances may be issued for new construction and substantial improvements and for other development necessary for the conduct of a functionally dependent use provided that the subdivisions (1) through (4) of subsection (a) of this section are satisfied and that the structure or other development is protected by methods that minimize flood damages during the base flood and create no additional threats to public safety.

(b) Appeal Board.

(1) The board of supervisors of the county shall hear and decide appeals and requests for variances from the requirements of this chapter.

(2) The board of supervisors of the county shall hear and decide appeals when it is alleged there is an error in any requirement, decision or determination made by the floodplain administrator in the enforcement or administration of this chapter.

(3) In passing upon such appeals and variances, the board of supervisors shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and

(A) The danger that materials may be swept onto other lands to the injury of others;

(B) The danger of life and property due to flooding or erosion damage;

(C) The susceptibility of the 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 in the community;

(E) The necessity to the facility of a waterfront location, where applicable;

(F) The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

(G) The compatibility of the proposed use with existing and anticipated development;

(H) The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;

(I) The safety of access to the property in times of flood for ordinary and emergency vehicles;

(J) The expected heights, velocity, duration, rate of rise and sediment transport of the floodwaters and the effects of wave action, and allowance for debris, if applicable, expected at the site;

(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 system, and streets and bridges.

(4) Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing items (A) through (K) of Section 23.09.040(b)(3) have been fully considered. As the lot size increases beyond the one-half acre, the technical justification required for issuing the variance increases.

(5) Upon consideration of the factors of subdivision (3) of subsection (b) of this section and the purposes of the ordinance codified in this section, the board of supervisors may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

(6) The floodplain administrator shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration upon request.

(7) Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with a lowest floor elevation below the regulatory flood elevation and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation. A copy of the notice shall be recorded by the floodplain administrator in the office of Marin County recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

(c) Appeal Procedure.

(1) Those aggrieved by a decision of any county department pursuant to this chapter may appeal such decision upon payment of a fee of one hundred dollars to the board of supervisors of the county.

(2) In passing upon such appeal, the board of supervisors shall consider all items delineated in subsections (a) and (b) of this section.

(Ord. 3293 § 14, 1999)

(a) A structure or the use of a structure or premises which was lawful before passage or amendment of Chapter 23.09 of the Marin County code and/or these rules but which is not in conformity with their provisions, may be continued as a nonconforming use subject to the following conditions:

(1) No such use shall be expanded, changed, enlarged or altered in any way which increases its nonconformity;

(2) Any substantial improvement of a nonconforming structure shall be made in compliance with the provisions of this chapter;

(3) If any nonconforming use or structure is destroyed by any means, including flood, to the extent of fifty percent or more of its market value immediately prior to the destruction, it shall not be reconstructed except in conformity with the provisions of this chapter.

(Ord. 3293 § 15, 1999)

(1) Violation of the provisions of this chapter or failure to comply with any of its requirements shall constitute an infraction. Any person who violates this chapter or fails to comply with any of its requirements shall, upon conviction thereof, be fined not more than fifty dollars for the first violation; a fine not exceeding one hundred dollars for a second violation of the same ordinance within one year; or a fine not exceeding two hundred fifty dollars for each additional violation of the same ordinance within one year. Each day such violation continues shall be considered a separate offense.

(2) Any violation of the provisions of this chapter are declared to be a nuisance and may be abated as provided for in Chapter 1.05 of this code. Nothing herein contained shall prevent the county of Marin from taking such other lawful actions as is necessary to prevent or remedy any violations.

(Ord. 3293 § 16, 1999)

The board of supervisors finds and declares that this chapter is not intended, and shall not be construed, as authorizing the county to exercise its power to adopt, amend or repeal this chapter or implementing administrative regulations in a manner which will take or damage private property for public use without the payment of just compensation therefor. This section is not intended to increase or decrease the rights of any owner of property under the Constitution of the state of California or of the United States.

(Ord. 3293 § 17, 1999)