Chapter 15.16 FLOOD DAMAGE PREVENTION

The legislature of the State of Nevada in NRS 278.020, 244A.057, and 543.020 confers upon local government units authority to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the county commission of Humboldt County does hereby adopt the following floodplain management regulations. (Ord. 1-04-10 § 1; Ord. 2-17-04)

15.16.020 Findings of fact.

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

B. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities, and when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed, elevated, or otherwise protected from flood damage also contribute to the flood loss. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 1.1. Formerly 15.16.010.)

15.16.030 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 do the following:

A. Protect human life and health;

B. Minimize expenditures of public money for costly flood control projects;

C. Minimize the need for rescue and relief efforts associated with flood and generally undertaken at the expense of the general public;

D. Minimize prolonged business interruptions;

E. Minimize damage to public facilities and utilities 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 blight areas;

G. Ensure that potential buyers are notified that property is in an area of special flood hazards;

H. Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions; and

I. Maintain qualifying standards for participation in the National Flood Insurance Program. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 1.2. Formerly 15.16.020.)

15.16.040 Methods of reducing flood losses.

In order to accomplish its purpose, this chapter includes methods and provisions for:

A. Restricting or prohibiting 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 floods, including facilities which such uses are protected against flood damage at the time of initial construction;

C. Controlling the alternation 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. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 1.3. Formerly 15.16.030.)

15.16.050 Definitions.

Unless specifically defined in this section, words or phrases used in this chapter shall be interpreted so as to give them meanings they have in common usage and to give this chapter its most reasonable applications.

“Accessory structure” means a structure used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds).

“Accessory use” means a use which is incidental and subordinate to the principal use of the parcel of land on which it is located.

“Alluvial fan” means a geomorphologic feature characterized by a cone- or fan-shaped deposit of clay, silt, sand, gravel, and boulders that have been eroded from mountain slopes, transported by flood flows, and deposited on the valley floor.

“Alluvial fan flooding” means flooding occurring on the surface of an alluvial fan or similar landform which originates at the apex and is characterized by high-velocity flows: active processes of erosion, sediment transport, deposition, and unpredictable flow paths.

“Anchoring” means a series of methods used to secure a structure to its footings or foundation wall so that it will not be displaced by flood or wind forces.

“Apex” means the highest point of an alluvial fan or similar landform below which the flow path of the major stream that formed the fan becomes unpredictable and alluvial fan flooding can occur.

“Appeal” means a request for a review of the county building department’s interpretation of any provision of this chapter or a request for a variance.

“Area of shallow flooding” means designated zones AO and AH on a community’s flood insurance rate map (FIRM) with a one percent or greater annual chance of flooding to an average depth of one to three feet where a clearly defined channel does not exist, where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

“Base flood” means the flood having a one percent chance of being equaled or exceeded in any given year. Also referred to as the “one-hundred-year flood.”

“Base flood elevation” means the height in relation to mean sea level expected to be reached by the waters of the base flood at pertinent points in the floodplain of riverine areas.

“Basement” means any area of the building having its floor subgrade (below ground level) on all sides. A subgrade crawl space is considered a basement unless it meets the minimum technical requirements defined in FEMA Technical Bulletin 11-01 (Crawl space Construction for Buildings Located in Special Flood Hazard Areas, 2001) and the community has adopted the standards of the International Building Code and International Residential Code.

“Community” means any state or area or political subdivision thereof, or any Indian tribe or authorized tribal organization, or authorized native organization, which has authority to adopt and enforce floodplain management regulations for the areas within its jurisdiction.

“Community rating system (CRS)” means a program developed by FIA to provide incentives for those communities in the regular program that have gone beyond the minimum floodplain management requirements to develop extra measures to provide protection from flooding.

“Conditional letter of map amendment (CLOMA)” means a letter from FEMA stating that a proposed structure that is not to be elevated by fill would not be inundated by the base flood if built as proposed.

“Conditional letter of map revision (CLOMR)” means procedures by which contractors, developers and communities can request review and determination by the federal insurance administrator of scientific and technical data for a proposed project, when complete and functioning effectively would modify the elevation of individual structures and parcels of land, stream channels, and floodplains on the FIRM.

“Conditional letter of map revision (based on fill) (CLOMR-F)” means a letter from FEMA stating that a parcel of land or proposed structure that is to be elevated by fill would not be inundated by the base flood if fill is placed on the parcel as proposed or the structure is built as proposed.

“Critical structures” means any structure for which even a slight chance of flooding would reduce or eliminate its designed function of supporting a community in an emergency. Fire stations, hospitals, municipal airports, police stations, communication antennas or towers, elder care facilities (retirement homes), fuel storage facilities, schools designated as emergency shelters, fresh water and sewage treatment facilities are some examples of critical structures.

“Date of construction” means the date that the building permit was issued provided the actual start of construction, repair, reconstruction, or improvement was within one hundred eighty days of the permit date.

“Designated floodway” means the channel of a stream and the portion of the adjoining floodplain designated by a regulatory agency to be kept free of further development to provide for unobstructed passage of flood flows.

“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 located within the area of special flood hazard.

“Digital flood insurance rate map (DFIRM)” means the official map, in digital format, on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. The DFIRM is the legal equivalent of the FIRM in communities where a DFIRM is available (see “Flood insurance rate map”).

“Dry floodproofing” means a floodproofing method used to design and construct buildings so as to prevent the entrance of floodwaters.

“Elevation certificate” means the elevation certificate required in order to properly rate “post- FIRM buildings,” which are buildings constructed after publication of the flood insurance rate map (FIRM), for flood insurance zones A1-A30, AE, AH, A (with BFE), VE, V1-V30, V (with BFE), AR, AR/A, AR/AE, AR/A1-A30, AR/AH, and AR/AO. The elevation certificate is not required for pre-FIRM buildings unless the building is being rated under the optional post-FIRM flood insurance rules.

“Enclosure” means that portion of an elevated building below the lowest elevated floor that is either partially or fully shut in by rigid walls.

“Encroachment” means the advance or infringement of uses, plant growth, excavation, fill, buildings, permanent structures or development, storage of equipment and materials, or any other physical object placed in the floodplain, that hinders the passage of water or otherwise affects flood flows.

“Erosion” means the process of the gradual wearing away of any landmass. This peril is not per se covered under the program. (See “Flood-related erosion”).

“Existing manufactured home (mobile 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 before the effective date of the floodplain management regulations adopted by a community.

“Expansion to a manufactured home (mobile 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, construction of streets, and either final site grading or the pouring of concrete pads).

“Federal Emergency Management Agency (FEMA)” means the federal agency under which the National Flood Insurance Program (NFIP) is administered.

“Federal Insurance Administration (FIA)” means the government unit, a part of Federal Emergency Management Agency (FEMA), that administers the National Flood Insurance Program (NFIP).

“Flash flood” means a flood that crests in a short period of time and is often characterized by high velocity flows. It is often the result of heavy rainfall in a localized area.

“Flood” or “flooding” or “floodwaters” means a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of floodwaters; the unusual and rapid accumulation of runoff of surface waters from any sources and mudslides (i.e., mudflows); and the condition resulting from flood-related erosion.

“Flood control” means keeping floodwaters away from specific developments or populated areas, areas by the construction of flood storage reservoirs, channel alterations, dikes and levees, bypass channels, or other engineering works.

“Flood hazard boundary map (FHBM)” means an official map of a community, issued by the administrator, where the boundaries of the flood, mudslide (i.e., mudflow) related erosion areas having special hazards have been designated as zones A, M, and/or E.

“Flood insurance study (FIS)” 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 administrator” means the community official designated by title to administer and enforce the floodplain management regulations. The floodplain administrator for Humboldt County is defined in HCC 15.16.110(A) to be the building official.

“Floodplain and flood-prone area” means any land area susceptible to being inundated by waters from any source. (See “Flooding.”)

“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 and floodplain management plans, regulations and ordinances.

“Floodplain management regulations” means this chapter, and any federal, state or local regulations plus community zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as grading and erosion control) and other applications of police power which control development in flood-prone areas to prevent and reduce flood loss and damage.

“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. Refer to FEMA Technical Bulletins TB-1 (Openings in Foundation Walls and Walls of Enclosures, 2008), TB-3 (Non-residential Floodproofing—Requirements and Certification, 1993), and TB-7 (Wet Floodproofing Requirements, 1993) for guidelines on dry and wet floodproofing.

“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. Also referred to as a “regulatory floodway.”

“Flood insurance rate map” (FIRM) means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. Includes digital flood insurance rate maps (DFIRM) in communities where a DFIRM is available (see “Digital flood insurance rate map”).

“Flood insurance risk zone designations” means the zone designations indicating the magnitude of the flood hazard in specific areas of a community. (See “Special flood hazard area.”)

1. “Zone A” means special flood hazard areas inundated by the one-hundred-year-flood; base flood elevations are not determined.

2. “Zone A1-30 and zone AE” means special flood hazard areas inundated by the one-hundred-year-flood; base flood elevations are determined.

3. “Zone AO” means special flood hazard areas inundated by the one-hundred-year-flood; with flood depths of one to three feet (usually sheet flow on sloping terrain); average depths are determined. For areas of alluvial fan flooding, velocities are also determined.

4. “Zone AH” means special flood hazard areas inundated by the one-hundred-year-flood; flood depths of one to three feet (usually areas of ponding); base flood elevations are determined.

5. “Zone AR” means special flood hazard areas that result from the decertification of a previously accredited flood protection system that is in the process of being restored to provide a one-hundred-year or greater level of flood protection.

6. “Zones AR/A1-30, AR/AE, AR/AH, AR/AO, and AR/A” means special flood hazard areas that result from the decertification of a previously accredited flood protection system that is in the process of being restored to provide a one-hundred-year or greater level of flood protection. After restoration is complete, these areas will still experience residual flooding from other flooding sources.

7. “Zone A99” means special flood hazard areas inundated by the one-hundred-year-flood to be protected from the one-hundred-year-flood by a federal flood protection system under construction; no base flood elevations determined.

8. “Zone B and zone X (shaded)” means areas of five-hundred-year-flood; areas subject to the one-hundred-year-flood with average depths of less than one foot or with contributing drainage area less than one square mile; and areas protected by levees from the base flood.

9. “Zone C and zone X (shaded)” means areas determined to be outside the five-hundred-year-floodplain.

10. “Zone D” means areas in which flood hazards are undetermined.

“Footing” means the enlarged base of a foundation wall, pier, or column, designed to spread the load of the structure so that it does not exceed the soil-bearing capacity.

“Foundation” means the underlying structure of a building usually constructed of concrete that supports the foundation walls, piers, or columns.

“Foundation walls” means a support structure that connects the foundation to the main portion of the building or superstructure.

“Fraud/victimization” is related to variances of this chapter; the variance granted must not cause fraud on or victimization to the public. In examining this requirement, the Humboldt County board of commissioners will consider the fact that every newly constructed building adds to government responsibilities, and remains a part of the community for fifty to one hundred years. Buildings permitted to be constructed below the base flood elevation are subject during all those years to increased risk of damage from floods, while future owners of the property and the community as a whole are subject to all the costs, inconvenience, danger, and suffering that those increased flood damages bring. Additionally future owners may be unaware of the risk potential to the property due to flood damage and the extremely high rates for flood insurance.

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

“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 marina facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and boat building and boat repair facilities, but does not include long-term storage or related manufacturing facilities.

“Governing body” means the local governing unit, county or municipality that is empowered to adopt and implement regulations to provide for public health, safety and general welfare of its citizenry.

“Hardship” is related to variances of this chapter. The exceptional hardship would result from a failure to grant the requested variance. Humboldt County requires the variance be exceptional, unusual, and pertain only to the property involved. Mere economic or financial hardship alone is not exceptional. Inconvenience, aesthetic considerations, physical handicaps, personal preferences, or the disapproval of one’s neighbors likewise cannot, as a rule, qualify as an exceptional hardship. All of these problems can be resolved through other means without granting a variance, even if the alternative is more expensive, or requires the property owner to build elsewhere or put the parcel to a different use than originally intended.

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

“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 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 without approved programs.

“Hydraulics hydrodynamic loads” means the science that deals with practical applications of water in motion. Forces imposed on structures by floodwaters due to the impact of moving water on the upstream side of the structure, drag along its sides, and eddies or negative pressures on its downstream side.

“Hydrology” means the science of the behavior of water in the atmosphere, on the earth’s surface and underground.

“Hydrostatic loads” means forces imposed on a flooded structure due to the weight of the water.

“Letter of map amendment (LOMA)” means the procedure by which any owner or lessee of property who believes his property has been inadvertently included in a special flood hazard area can submit scientific and technical information to the Federal Insurance Administrator for review to remove the property from said area. The administrator will not consider a LOMA if the information submitted is based on alteration of topography or new hydrologic or hydraulic conditions since the effective date of the FIRM.

“Letter of map revision (LOMR)” means an official revision to a currently effective FIRM. A LOMR officially changes flood zone, floodplain and floodway designations, flood elevations and planimetric features.

“Letter of map revision (based on fill) (LOMR-F)” means a letter from FEMA stating that an existing structure or parcel of land that has been elevated by fill would not be inundated by the base flood.

“Levee” means a manmade structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control or divert the flow of water so as to provide protection from temporary flooding.

“Levee system” means a flood protection system, which consists of a levee, or levees, and associated structures, such as closure and drainage devices, which are constructed and operated in accordance with sound engineering practices.

“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 found in HCC 15.16.170(A)(1).

“Manufactured home (mobile home)” means a structure that is transportable in one or more sections, built on a permanent chassis and designed to be used with or without a permanent foundation when connected to the required utilities. The term “manufactured home” does not include “recreational vehicles.”

“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. For the purposes of determining substantial improvement, market value pertains only to the structure in question. It does not pertain to the land, landscaping or detached accessory structures on the property. For determining improvement, the value of the land must always be subtracted.

Acceptable estimates of market value can be obtained from the following sources:

1. Independent appraisals by a professional appraiser.

2. Detailed estimates of structure’s actual cash value (used as a substitute for market value based on the preference of the community).

3. Property appraisals used for tax assessment purposes (adjusted assessed value, used as a screening tool).

4. The value of buildings taken from NFIP claims data (used as a screening tool).

5. Qualified estimates based on sound professional judgment made by staff of the local building department or local or state tax assessor’s office.

As indicated above, some market value estimates should only be used as screening tools to identify those structures where the substantial improvement ratios are obviously less than or greater than fifty percent (e.g., less than forty percent or greater than sixty percent). For structures that fall between the forty percent and sixty percent range, more precise market value estimates should be used.

“Mobile home” has the same meaning as “manufactured home.”

“North American Vertical Datum (NAVD)” means a vertical control used as a reference for establishing various elevations within the floodplain based upon the general adjustment of the North American Vertical Datum of 1988. Flood elevations on digital flood insurance rate maps for Nevada communities are referenced to NAVD 88.

“National Geodetic Vertical Datum (NGVD),” as corrected in 1929, is a vertical control used as a reference for establishing various elevations within the floodplain. Flood elevations on flood insurance rate maps published for Nevada communities prior to 2007 were typically referenced to NGVD 29.

“Natural grade” means the grade unaffected by construction techniques such as fill, landscaping, or berming.

“New construction” means structures of which the start of construction commenced on or after the effective date of an initial FIRM or after December 31, 1974, whichever is later, including any subsequent improvements.

“New manufactured home (mobile home) 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 effective date of these floodplain management regulations adopted by Humboldt County.

“Nonresidential” includes, but is not limited to: small business concerns, churches, schools, farm buildings (including grain bins and silos), poolhouses, clubhouses, recreational buildings, mercantile structures, agricultural and industrial structures, warehouses, and hotels or motels with normal room rentals for less than six months duration.

“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.

“One-hundred-year-flood” has the same meaning as “base flood.”

“Physical map revisions (PMR)” means a reprinted NFIP map incorporating changes to floodplains, floodways, or flood elevations. Because of the time and cost involved to change, reprint, and redistribute an NFIP map, a PMR is usually processed when a revision reflects large scope changes.

“Ponding hazard” means a flood hazard that occurs in flat areas when there are depressions in the ground that collect “ponds” of water. The ponding hazard is represented by the zone designation AH on the FIRM.

“Post-FIRM construction” means construction or substantial improvement that started on or after the effective date of the initial flood insurance rate map (FIRM) of the community or after December 31, 1974, whichever is later.

“Pre-FIRM construction” means construction or substantial improvement which started on or before December 31, 1974, or before the effective date of the initial flood insurance rate map (FIRM) of the community, whichever is later.

“Principal residence” means a single-family dwelling in which, at the time of loss, the named insured or the named insured’s spouse has lived for either (1) eighty percent of the calendar year, or (2) eighty percent of the period of ownership, if less than one year.

“Principal structure” means a structure used for the principal use of the property as distinguished from an accessory use.

“Program deficiency” means a defect in a community’s floodplain management regulations or administrative procedures that impairs effective implementation of those floodplain management regulations.

Proper Openings for Enclosures (Applicable to Zones A, A1-A30, AE, AO, AH, AR, and AR Dual). All enclosures below the lowest floor must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. A minimum of two openings, with positioning on at least two walls, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding must be provided.

“Public safety/nuisance” is related to variances in this chapter. The granting of a variance must not result in anything which is injurious to safety or health of the entire community or neighborhood, or any number of persons, or unlawfully obstructs the free passage or use, in the customary manner, of any navigable lake, or river, bay, stream, canal, or basin.

“Recreational vehicle” means a vehicle, either motor drawn or self-propelled, designed and capable of use for recreational or travel purposes, not classified as a mobile home under the mobile home code, ten feet or under in width and forty feet or under in length, capable of use as a residence.

“Riverine” means relating to, formed by, or resembling a river including tributaries, streams, brooks, etc.

Sheet Flow Area. Has the same meaning as “area of shallow flooding.”

“Special flood hazard area (SFHA)” means a darkly shaded area on a flood hazard boundary map (FHBM) or a flood insurance rate map (FIRM) that identifies an area that has a one percent chance of being flooded in any given year (one-hundred-year floodplain). Over a thirty-year period, the life of most mortgages, there is at least a twenty-six percent chance that this area will be flooded. The FIRM identifies these shaded areas as FIRM zones A, AO, AH, A1-A30, AE, A99, AR, AR/A, AR/AE, AR/A1-A30, AR/AH, AR/AO, V, V1-V30, and VE. See “Flood insurance risk zone designations.”

“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 and eighty 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.

“Structures” means a walled or roofed building that is principally above ground and includes gas or liquid storage tanks and manufactured homes.

“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 market value of the structure before damage occurred.

“Substantial improvement” means any repair, addition or improvement of a structure, the cost of which equals or exceeds fifty 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. This term does not, however, include either:

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

2. Any alteration of a historic structure; provided, that the alteration will not preclude the structure’s continued designation as a “historic place.”

“Variance” means a grant of relief from the requirements of this chapter which permits construction in any manner that would otherwise be prohibited by this chapter.

“Violation” means the failure of a structure or other development to be fully compliant with this chapter. A structure or other development in a special flood hazard without an 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.

“Water surface elevation” means the height, in relation to the North American Vertical Datum (NAVD) of 1988, or other datum, where specified, of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas.

“Watercourse” means a lake, river, creek, stream, wash, arroyo, channel or other topographic feature on or over which waters flow at least periodically. “Watercourse” includes specifically designated areas in which substantial flood damage may occur. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 2. Formerly 15.16.040.)

15.16.060 Applicable lands.

This chapter applies to all areas of special flood hazard within the jurisdiction of the county. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 3.1. Formerly 15.16.050.)

15.16.070 Basis for establishing areas of special flood hazard.

A. The areas of special flood hazard identified by the Federal Insurance Administration (FIA) of the Federal Emergency Management Agency (FEMA) in the flood insurance study (FIS) dated March 17, 2010, and accompanying flood insurance rate map (FIRM) and flood boundary and floodway maps (FBFM) dated March 17, 2010, and all subsequent amendments and/or revisions are hereby adopted by reference and declared to be part of the chapter. The FIS and attendant mapping is the minimum area of applicability of this chapter and may be supplemented by studies for other areas which allow implementation of this chapter and which is recommended to the Humboldt County board of commissioners by the floodplain administrator. The FIS, FIRMs and FBRMs are on file at the Humboldt County Building Department, 25 W. Fourth St, Winnemucca, NV 89445.

B. For areas of the county not included in the Federal Insurance Administration report, areas of special flood hazard will be established by the county building department from historical and other information compiled from the best data available.

C. The county shall utilize maps required by the subdivision and parceling review process to determine areas of special flood hazard. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 3.2. Formerly 15.16.060.)

15.16.080 Compliance.

No structures or land shall hereafter be constructed, located, extended, converted or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of the provisions of this chapter by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction thereof be punished in accordance with HCC 1.08.020 and in addition shall pay all costs and expenses involved in the case. Nothing herein contained shall prevent Humboldt County from taking such other lawful action as is necessary to prevent or remedy any violation. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 3.3. Formerly 15.16.070.)

15.16.081 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 other ordinances, easements, covenants or deed restrictions conflict or overlap, whichever imposes the more stringent restrictions shall prevail. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 3.4. Formerly 15.16.080.)

15.16.082 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 or repeal any other powers and granted under state statutes. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92. Formerly 15.16.081.)

15.16.090 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 height 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 Humboldt County, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this chapter of any administrative decision lawfully made under this chapter. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92. Formerly 15.16.082.)

15.16.091 Declaration of public nuisance.

Every new structure, building, fill, excavation or development located or maintained within any area of special flood hazard after May 1991 in violation of this chapter is a public nuisance per se and may be abated, prevented or restrained by action of this political subdivision. (Ord. 1-04-10 § 1)

15.16.092 Abatement of violations.

Within thirty days of discovery of a violation of this chapter, the floodplain administrator shall submit a report to the Humboldt County board of commissioners which shall include all information available to the floodplain administrator which is pertinent to said violation. Within thirty days of receipt of this report, the Humboldt County board of commissioners shall either:

A. Take any necessary action to effect the abatement of such violation; or

B. Issue a variance to this chapter in accordance with the provisions of HCC 15.16.180; or

C. Order the owner of the property upon which the violation exists to provide whatever additional information may be required for their determination. Such information must be provided to the Humboldt County building department within thirty days of such order, and the building official shall submit an amended report to the Humboldt County board of commissioners within twenty days. At their next regularly scheduled public meeting, Humboldt County board of commissioners shall either order the abatement of said violation or they shall grant a variance in accordance with the provisions of HCC 15.16.180.

D. Submit to the administrator of the Federal Insurance Administration a declaration for denial of insurance, stating that the property is in violation of a cited statute or local law, regulation or ordinance, pursuant to Section 1316 of the National Flood Insurance Act of 1968 as amended. (Ord. 1-04-10 § 1)

15.16.093 Unlawful acts.

It is unlawful for any person to divert, retard or obstruct the flow of waters in any watercourse whenever it creates a hazard to life or property without securing the written authorization of the Humboldt County board of commissioners. Where the watercourse is a delineated floodplain, it is unlawful to excavate or build any structure affecting the flow of waters without securing written authorization of the floodplain administrator. (Ord. 1-04-10 § 1)

15.16.094 Severability.

This chapter and the various parts thereof are hereby declared to be severable. Should any section of this chapter be declared by the courts to be unconstitutional or invalid, such decisions shall not affect the validity of this chapter as a whole, or any portion thereof other than the section so declared to be unconstitutional or invalid. (Ord. 1-04-10 § 1)

15.16.100 Land use in floodways.

All areas of special flood hazard established in HCC 15.16.070 are designated floodplains. Since the floodway, as defined in HCC 15.16.050, is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

A. Encroachments, including fill, new construction, substantial improvements and other development are prohibited unless certification by a registered professional engineer or architect is provided demonstrating that encroachments will not result in any increase in flood levels during the occurrence of the base flood discharge.

B. If subsection (A) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of HCC 15.16.130 through 15.16.174, inclusive. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 4. Formerly 15.16.090.)

15.16.110 Development permit required.

A. The building official is hereby appointed local floodplain administrator to administer and implement this chapter by granting or denying floodplain development permits in accordance with its provisions.

B. A floodplain development permit is hereby established for all construction and other development to be undertaken in areas of special flood hazard in Humboldt County for the purpose of protecting its citizens from increased flood hazards and ensuring new development is constructed in a manner that minimizes its exposure to flooding. It shall be unlawful to undertake any development in an area of special flood hazard, as shown on the flood insurance rate map enumerated in HCC 15.16.170, without a valid floodplain development permit. Applications for a permit shall be made on forms furnished by the local floodplain administrator and may include, but not be limited to: plans in duplicate drawn to scale showing the nature, location, dimensions, and elevation of the area in question, existing or proposed structures, fill, storage of materials, drainage facilities, and the location of the foregoing. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 5.1. Formerly 15.16.100.)

15.16.111 Permit application.

The applicant shall provide at least the following information, where applicable. Additional information may be required on the permit application forms.

A. The proposed elevation in relation to mean sea level of the lowest floor (including basement) of all residential and nonresidential structures whether new or substantially improved to be located in zones A, A1-A30, AE, and AH, if base flood elevation data is available.

B. In zone AO the proposed elevation in relation to mean sea level of the lowest floor (including basement) and the elevation of the highest adjacent grade of all residential and nonresidential structures whether new or substantially improved.

C. The proposed elevation in relation to mean sea level to which any new or substantially improved nonresidential structure will be floodproofed.

D. A certificate from a licensed professional engineer or architect in the State of Nevada that any utility floodproofing meets the criteria in HCC 15.16.140.

E. A certificate from a licensed professional engineer or architect in the State of Nevada that any nonresidential floodproofed structures meet the criteria in HCC 15.16.170(E).

F. When a watercourse will be altered or relocated as a result of the proposed development, the applicant must submit the maps, computations, and other materials required by the Federal Emergency Management Agency (FEMA) to process a letter of map revision (LOMR) and pay any fees or other costs assessed by FEMA for processing the revision.

G. A technical analysis, by a professional engineer licensed in the State of Nevada, showing the proposed development located in the special flood hazard area will not cause physical damage to any other property.

H. When there is no base flood elevation data available for zone A from any source, the base flood elevation data will be provided by the permit applicant for all proposed development of subdivisions, manufactured home and recreational vehicle parks in the special flood hazard areas, or all developments of fifty lots or five acres, whichever is less. (Ord. 1-04-10 § 1)

15.16.115 County building department—Duties.

Duties of the county building department are extended to include, but are not limited to:

A. Permit Review.

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

2. Review subdivisions and other proposed new development, include manufactured homes and recreational vehicle parks to determine whether the proposed development site will be reasonably safe from flooding. When the proposed building site is located in the special flood hazard, all new construction and substantial improvements will meet the applicable standards of HCC 15.16.170.

3. Determine whether any proposed development in the special flood hazard area may result in physical damage to any other property to include stream bank erosion and any increase in velocities or that it does not adversely affect the carrying capacity of the areas where base flood elevations have been determined but a floodway has not been designated. For purposes of this chapter, “adversely affects” means 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. To assist the local floodplain administrator in making this determination, the permit applicant may be required to submit additional technical analyses.

4. For construction on an existing structure, determine if proposed construction constitutes substantial improvement or repair of substantially damaged structure.

5. Review all permits to determine if reconstruction could feasibly be effected on the site outside the area of special flood hazard.

6. Review all development permits to determine that all necessary permits have been obtained from those federal, state, or local government agencies from which prior approval is required.

7. Review all development permits to determine if the proposed development is located in the floodway. If located in the floodway, assure that the encroachment provisions of HCC 15.16.100 are met.

B. Use of Other Flood Data.

1. When the Federal Emergency Management Agency has designated special flood hazard areas on the community’s flood insurance rate maps (FIRMs) but has neither produced water surface elevation data nor identified a floodway, the local floodplain administrator shall attempt to obtain, review and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source, including data developed pursuant to HCC 15.16.118, as criteria for requiring new construction, substantial improvements or other proposed development meets the requirements of this chapter.

2. When base flood elevations are not available, the local floodplain administrator may use flood information from any other authoritative source, such as historical data, to establish flood elevations within the special flood hazard areas. This information shall be submitted to the Humboldt County board of commissioners for adoption.

C. Alteration of Watercourses. Prior to issuing a permit for any alteration or relocation of watercourse the local floodplain administrator must:

1. Have processed letter of map revision (LOMR).

2. Notify all adjacent communities, Nevada’s National Flood Insurance Program Coordinator, and submittal of evidence of such notification to the Federal Insurance Administration, and the Federal Emergency Management Agency.

3. Determine that the potential permit recipient has provided for maintenance within the altered or relocated portion of said watercourse so that the flood carrying capacity is not diminished. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 5.2. Formerly 15.16.110.)

15.16.116 Inspections.

The local floodplain administrator or designee shall make periodic inspections throughout the period of construction to monitor compliance with the requirements of the floodplain development permit or any variance provisions. (Ord. 1-04-10 § 1)

15.16.117 Stop work orders.

The local floodplain administrator shall issue, or cause to be issued, a stop work order for any floodplain development found noncompliant with the provisions of this chapter or conditions of the development permit and all development found ongoing without a floodplain development permit. Disregard of a stop work order shall subject the violator to the penalties described in HCC 15.16.080. (Ord. 1-04-10 § 1)

15.16.118 Retaining floodplain development documentation.

The local floodplain administrator shall obtain and retain for public inspection and have available for the National Flood Insurance Program Coordinator or the Federal Emergency Management Agency representative conducting a community assistance visit, the following:

A. Floodplain development permits and certificates of compliance.

B. Elevation certificates with record of certification required by HCC 15.16.170(D).

C. Certifications required by HCC 15.16.170(E).

D. Elevation certificates with record of certification required by HCC 15.16.170(D).

E. Elevation certificates with record of certification of elevation required by HCC 15.16.150.

F. Certification required by HCC 15.16.170(E)(3).

G. Variances issued pursuant to HCC 15.16.180.

H. Notices required under HCC 15.16.115(C)(2). (Ord. 1-04-10 § 1)

15.16.119 Map determinations.

The local floodplain administrator may make map interpretations where needed, in writing with appropriate documentation, as to the exact location of the boundaries of the areas of special flood hazard and where there appears to be a conflict between a mapped boundary and actual field conditions. (Ord. 1-04-10 § 1)

15.16.120 Appeals.

The board of appeals of Humboldt 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. (Ord. 1-04-10 § 1)

15.16.121 Submission of new technical data.

When Humboldt County’s base flood elevations either increase or decrease resulting from physical changes affecting flooding conditions, as soon as practicable, but not later than six months after the date such information becomes available, Humboldt County will submit the technical or scientific data to FEMA. Such submissions are necessary so that upon confirmation of the physical changes affecting flooding conditions, risk premium rates and floodplain management requirements will be based upon current data. (Ord. 1-04-10 § 1)

15.16.130 Flood hazard reduction—Buildings.

A. In all areas of special flood hazards, all new construction and substantial improvements shall be:

1. Designed by a Nevada licensed architect or engineer and adequately anchored to prevent flotation, collapse or lateral movement of the structure;

2. Constructed with materials and utility equipment resistant to flood damage; and

3. Constructed by methods and practices that minimize flood damage.

B. In all areas of special flood hazard, all manufactured homes must likewise be anchored to prevent flotation, collapse or lateral movement, and shall be installed using methods and practices that minimize flood damages. Anchoring methods may include, but are not limited to, use of over-the-top or frame ties to ground anchors. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 6.1. Formerly 15.16.120.)

15.16.140 Flood hazard reduction—Utilities.

In all areas of special flood hazard all new and replacement water supply and sanitary sewage systems shall be designed by a Nevada licensed architect or engineer to minimize or eliminate infiltration of floodwaters in the system and discharge from systems into floodwaters, and on-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. Sanitary sewer and storm drainage systems for buildings that have openings below base flood elevation shall be provided with automatic backflow valves or other automatic backflow devices that are installed in each discharge line passing through a building’s exterior wall. Electrical, heating, ventilation, plumbing, and air conditioning equipment and all other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 6.2. Formerly 15.16.130.)

15.16.150 Flood hazard reduction—Subdivision and new development.

All subdivision proposals, parcel maps and other new development, including manufactured home parks or subdivisions, shall be reviewed by the county planning department to determine whether such proposals will be reasonably safe from flooding. If a subdivision proposal or other proposed new development is in a flood-prone area, any such proposals shall be reviewed by the county planning department to assure that a Nevada registered professional engineer has stamped the plans certifying that:

A. Such proposals are consistent with the need to minimize flood damage.

B. All subdivision plans will provide the elevation of proposed structures and pads. If the site is filled above the base flood, the final lowest floor and pad elevation shall be certified and provided to the floodplain administrator.

C. All public utilities and facilities, such as sewer, gas, electrical, and water systems are located and constructed to minimize or eliminate flood damage.

D. Adequate drainage is provided to reduce exposure to flood hazards.

E. Additionally all subdivision proposals will demonstrate, by providing a detailed hydrologic and hydraulic analyses that the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevations of the base flood more than one foot at any point within the floodplain.

F. Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain at least fifty lots or five acres (whichever is less). This data shall be provided by the applicant and certified by a Nevada registered professional engineer. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92; Ord. 7-6-87B § 6.3. Formerly 15.16.140.)

15.16.160 Review of building permits.

Where elevation data is not available either through the flood insurance study or from other authoritative source (HCC 15.16.115(B)), applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet above grade in these zones may result in higher insurance rates. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 2-17-04; Ord. 4-17-92. Formerly 15.16.150.)

15.16.170 Specific standards.

In all areas of special flood hazards where base flood elevation data has been provided as set forth in HCC 15.16.070 or 15.16.115(B), the following provisions are required:

A. Anchoring.

1. 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.

2. All manufactured homes shall meet the anchoring standards of HCC 15.16.172.

B. Construction Materials and Methods. All new construction and substantial improvements shall be constructed:

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

2. Using methods and practices that minimize flood damage;

3. Ensure electrical, heating, ventilation, plumbing, air conditioning equipment and other service facilities are designed or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

C. Elevation Requirements for Lowest Floor.

1. Residential Construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement:

a. In zone A, elevated to or above the base flood elevation, as determined by this community.

b. In all other zones, elevated to or above the base flood elevation.

D. Lowest Floor Certificate Requirements. Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor and verified by the county building inspector to be properly elevated. The certification shall be provided to the floodplain administrator using the current FEMA elevation certificate.

E. Nonresidential Construction. New shall either be elevated to conform with subsection (C) of this section or together with attendant utility and sanitary facilities;

1. Be floodproofed so that below the elevation recommended under subsection (C) of this section the structure is watertight with walls substantially impermeable to the passage of water;

2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

3. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the county building department as set forth in subsection (D) of this section.

F. Requirements for Areas Below the Lowest Floor.

1. All new construction and substantial improvements 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 floodwaters. Designs for meeting this requirement shall follow the guidelines in FEMA Technical Bulletins TB-1 (Openings in Foundation Walls and Walls of Enclosures, 2008) and TB-7 (Wet Floodproofing Requirements, 1993) and must either be certified by a licensed professional engineer or architect to meet or exceed the following minimum criteria:

a. A minimum of two openings that have a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided.

b. The bottom of all openings shall be no higher than one foot above grade.

c. Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.

2. Garages and Low Cost Accessory Structures.

a. Attached Garages.

i. A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry of floodwater in accordance with subsection (F)(1) of this section. Areas of the garage below the BFE must be constructed with flood resistant material in accordance with subsection (B) of this section.

ii. A garage attached to a nonresidential structure must meet the above requirements or be floodproofed. For guidance on below grade parking areas, see FEMA Technical Bulletin TB-6 (Below Grade Parking Requirements, 1993).

b. Detached Garages and Accessory Structures.

i. Accessory structures used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in HCC 15.16.050, may be constructed such that its floor is below the base flood elevation (BFE), provided the structure is designed and constructed in accordance with the following requirements:

(A) Use of the accessory structure must be limited to parking or limited storage;

(B) The portions of the accessory structure located below the BFE must be built using flood-resistant materials;

(D) Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the BFE;

ii. The accessory structure must comply with floodplain encroachment provisions in HCC 15.16.174; and

(A) The accessory structure must be designed to allow for the automatic entry of floodwaters in accordance with subsection (F)(1) of this section.

iii. Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in subsection (F)(1) of this section. (Ord. 1-04-10 § 1; Ord. 2-17-04; Ord. 4-17-92. Formerly 15.16.160.)

15.16.171 Standards for critical structures.

Critical structures are not authorized in a special flood area, unless:

A. All alternative locations in flood zone X have been considered and rejected.

B. All alternative locations in flood zone shaded X have been considered and rejected.

If the floodplain administrator determines the only practical alternative location for the development of a new or substantially improved critical structure is in a special flood hazard area he must give public notice of the decision and reasons for the elimination of all alternative locations. (Ord. 1-04-10 § 1)

15.16.172 Standards for manufactured homes.

A. All manufactured homes that are placed or substantially improved within zones A and AE and on the community’s flood insurance rate map, on sites located:

1. Outside of manufactured home park or subdivision;

2. In a new manufactured home park or subdivision;

3. In an expansion to an existing manufactured home park or subdivision; or

4. In an existing manufactured home park or subdivision on a site upon which a manufactured home has incurred “substantial damage” as a result of a flood shall be elevated on a permanent foundation so that the lowest floor will be 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. Methods of anchoring 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 to be placed or substantially improved on sites in an existing manufactured home park, subdivision or parcel within zones A and AE on the community’s flood insurance rate map that are not subject to the provisions of HCC 15.16.171 will be elevated so that either:

1. The bottom of the structural form or the lowest point of the manufactured home is at or above base flood level; or

2. 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 inches in height above grade and securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

C. Within zone A, when no base flood elevation data is available, new and substantially improved manufactured homes shall have the floor elevated at least three feet above the highest adjacent grade. (Ord. 1-04-10 § 1; Ord. 4-17-92)

15.16.173 Standards for recreational vehicles.

All recreational vehicles placed on sites within areas of special flood hazard will either:

A. Be on the site for fewer than thirty consecutive days;

B. Be fully licensed and ready for highway use. A recreational vehicle is ready for quick 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. Will meet the permit requirements of HCC 15.16.111 and the elevation and anchoring requirements for manufactured homes in HCC 15.16.172(A)(4). (Ord. 1-04-10 § 1)

15.16.174 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. If a floodway has not been designated within the special flood hazard areas established in HCC 15.16.070, no new construction, substantial improvement, or other development (including fill) shall be permitted within zones A1-30 and AE, unless it has been demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community.

B. In designated floodways located within the special flood hazard areas established in HCC 15.16.070 encroachment shall be prohibited, including fill, new construction, substantial improvements, storage of equipment or supplies, and any 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 community during the occurrence of the base flood discharge, and the Federal Emergency Management Agency has issued a conditional letter of map revision (CLOMR).

C. If this section has been satisfied, all proposed new development and substantial improvements will comply with all other applicable flood hazard reduction provisions of HCC 15.16.170. (Ord. 1-04-10 § 1)

15.16.180 Variance procedure.

The variance criteria set forth in this section are based on the general principles of zoning law that variances pertain to a piece of property and are not personal in nature. A variance may be granted for a parcel of property with physical characteristics so unusual that complying with the requirements of this chapter would create an exceptional hardship to the applicant or the surrounding property owners. The characteristics must be unique to the property and not be shared by adjacent parcels. The unique characteristic must pertain to the land itself, not to the structure, its inhabitants, or the property owners.

It is the duty of Humboldt County to help protect its citizens from flooding. This need is so compelling and the implications of the cost of insuring a structure built below flood level are so serious that variances from the flood elevation or from other requirements in the flood ordinance are quite rare. The long-term goal of preventing and reducing flood loss and damage can only be met if variances are strictly limited. Therefore, the variance guidelines provided in this section are more detailed and contain multiple provisions that must be met before a variance can be properly granted. The criteria are designed to screen out those situations in which alternatives other than a variance are more appropriate.

If, upon review, the Administrator of FEMA determines that community practices indicate a pattern of issuing variances that is inconsistent with the objectives of sound floodplain management, the community may be suspended from the National Flood Insurance Program.

A. Appeal Board.

1. The building appeal board as established by Humboldt County shall hear and decide appeals and requests for variances from the requirements of this chapter.

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

3. In passing upon such applications, the building appeal board 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 to 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 owner and future owners of the property;

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

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

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, durations, rate of rise and sediment transport of the floodwaters expected at the site; and

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

4. Any applicant to whom a variance is granted shall be given written notice over the signature of a community official that:

a. The issuance of a variance to construct a structure below the base flood level will result in increased premium rates for flood insurance up to amounts as high as twenty-five dollars for one hundred dollars of insurance coverage;

b. Such construction below the base flood level increases risk to life and property. It is recommended that a copy of the notice shall be recorded by the floodplain administrator in the office of the Humboldt County recorder and shall be recorded in a manner so that it appears as an exception on the title of the affected parcel of land. The floodplain administrator will maintain a record of all variance actions, including justification for their issuance, and report such variances issued in its biennial report submitted to the Federal Insurance Administration, Federal Emergency Management Agency.

B. Conditions for Variances.

1. Generally, the only condition under which a variance from the elevation standard may be issued is 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 procedures of HCC 15.16.111 and 15.16.170 have been fully considered. As the lot size increases the technical justification required for issuing the variance increases.

2. Variances may be issued for the repair or rehabilitation of “historic structures” as defined in HCC 15.16.050 upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as an historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.

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

4. Variances shall only be issued upon a determination that the variances are the “minimum necessary,” considering the flood hazard, to afford relief. “Minimum necessary” means to afford relief with a minimum of deviation from the requirements of this chapter. For example, in the case of variances to an elevation requirement, this means that Humboldt County need not grant permission for the applicant to build at grade, or even to whatever elevation the applicant proposes, but only to the elevation which Humboldt County believes will both provide relief and preserve the integrity of the local ordinance.

5. Variances shall only be issued upon:

a. A showing of good and sufficient cause;

b. A determination that failure to grant the variance will not result in exceptional “hardship” as defined in HCC 15.16.050 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 as defined in HCC 15.16.050, cause fraud on or victimization as defined in HCC 15.16.050 of the public or conflict with existing local laws or ordinances.

6. Variances may be issued for new construction, substantial improvement, and other proposed new development necessary for the conduct of a functionally dependent use; provided, that the provisions of this subsection (B) are satisfied and that the structure or other development is protected by methods that minimize flood damages during the base flood and does not result in additional threats to public safety and does not create a public nuisance.

7. Upon consideration of all the factors of subsection (A) of this section and the purposes of this chapter Humboldt County may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

8. Variances as interpreted in the National Flood Insurance Program are based on the general zoning law principle that they pertain to a physical piece of property; they are not personal in nature and do not pertain to the structures, its inhabitants, economic or financial circumstances. They primarily address small lots in densely populated residential neighborhoods. As such, variances from the flood elevations should be quite rare.

9. Variances may be issued for nonresidential buildings in very limited circumstances to allow a lesser degree of floodproofing than watertight or dry-floodproofing, where it can be determined that such action will have low damage potential, complies with all other variance criteria except subsection (B)(5)(a) of this section and otherwise complies with HCC 15.16.130(A). (Ord. 1-04-10 § 1; Ord. 4-17-92. Formerly 15.16.115.)

15.16.190 Letters of map revisions/amendments.

National Flood Insurance Program regulations provide procedures to remove property from the one-hundred-year floodplain or from a special flood hazard area. Amendments and revisions to community flood insurance rate maps cannot adversely impact the floodplain or floodway delineations of the level of the one-hundred-year flood.

There are several procedures provided whereby the Federal Insurance Administrator will review information from the community, an owner, or a lessee of property where it is believed the property should not be included in a special flood hazard area.

Submissions to FEMA for revisions to effective flood insurance studies (FISs) by individual and community requesters will require the signing of application/certification forms. These forms will provide FEMA with assurance that all pertinent data relating to the revision is included in the submittal. They will also assure that: (1) the data and methodology are based on current conditions; (2) qualified professionals have assembled data and performed all necessary computations; and (3) all individuals and organizations impacted by proposed changes are aware of the changes and will have an opportunity to comment on them. FEMA procedures permit the following types of request:

A request for a revision to the effective FIS information (FIRM, FBFM, and/or FIS report) is usually a request that FEMA replace the effective floodplain boundaries, flood profiles, floodway boundaries, etc., with those determined by the requester. Before FEMA will replace the effective FIS information with the revised, the requester must: (1) provide all of the data used in determining the revised floodplain boundaries, flood profiles, floodway boundaries, etc.; (2) provide all data necessary to demonstrate that the physical modifications to the floodplain have been adequately designed to withstand the impacts of the one percent annual chance flood event and will be adequately maintained; (3) demonstrate that the revised information (e.g., hydrologic and hydraulic analyses and the resulting floodplain and floodway boundaries) are consistent with the effective FIS information.

Requests for amendments or revisions to FEMA maps must be reviewed and submitted to FEMA by the Humboldt County board of commissioners with the applicant for a map amendment or revision required to prepare all the supporting information and appropriate FEMA forms.

The scientific or technical information to be submitted with these requests may include, but is not limited to, the following:

A. An actual copy of the recorded plat map bearing the seal of the appropriate recordation official, county clerk or recorder of deeds indicating the official recordation and proper citation, deed or plat book volume and page number, or an equivalent identification where annotation of the deed or plat book is not the practice.

B. A topographical map showing:

1. Ground elevation contours in relation to the NGVD (National Geodetic Vertical Datum).

2. The total area of the property in question.

3. The location of the structure or structures located on the property in question.

4. The elevation of the lowest adjacent grade to a structure or structures.

5. An indication of the curvilinear line which represents the area subject to inundation by a base flood. The curvilinear line should be based upon information provided by an appropriate authoritative source, such as a federal agency, department of water resources, a county water control district, a county or city engineer, a Federal Emergency Management Agency Flood Insurance Study, or a determination by a registered professional engineer.

C. A copy of the FHBM or FIRM indicating the location of the property in question.

D. A certification by a registered professional engineer or licensed land surveyor that the lowest grade adjacent to the structure is above the base flood elevation.

E. The completion of the appropriate forms in the Federal Emergency Management Agency’s Packets, Amendments and Revisions to National Flood Insurance Program Maps. (MT-1 FEMA FORM 81-87 Series and MT-2 FEMA FORM 81-89 Series). (Ord. 1-04-10 § 1)

15.16.200 Crawl space construction.

This section applies to buildings with crawl spaces up to two feet below grade. Below grade crawl space construction in accordance with the requirements listed below will not be considered basements.

A. The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Crawl space construction is not allowed in areas with flood velocities greater than five feet per second unless the design is reviewed by a qualified design professional, such as a registered architect or professional engineer;

B. The crawl space is an enclosed area below the BFE and, as such, must have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. For guidance on flood openings, see FEMA Technical Bulletin TB-1 (Openings in Foundation Walls and Walls of Enclosures, 2008);

C. Portions of the building below the BFE must be constructed with materials resistant to flood damage. This includes not only the foundation walls of the crawl space used to elevate the building, but also any joists, insulation, or other materials that extend below the BFE; and

D. Any building utility systems within the crawl space must be elevated above BFE or designed so that floodwaters cannot enter or accumulate within the system components during flood conditions.

E. Requirements for all below grade crawl space construction, in addition to the above requirements, to include the following: The interior grade of a crawl space below the BFE must not be more than two feet below the lowest adjacent exterior grade (LAG), shown as D in Figure 3 of FEMA Technical Bulletin 11-01 (Crawl space Construction for Buildings Located in Special Flood Hazard Areas, 2001);

F. The height of the below grade crawl space, measured from the interior grade of the crawl space to the top of the crawl space foundation wall, must not exceed four feet (shown as L in Figure 3 of Technical Bulletin 11-01, Crawl Space Construction for Buildings Located in Special Flood Hazard Areas, 2001) at any point;

G. There must be an adequate drainage system that removes floodwaters from the interior area of the crawl space within a reasonable period of time after a flood event, not to exceed seventy-two hours; and

H. The velocity of floodwaters at the site should not exceed five feet per second for any crawl space. For velocities in excess of five feet per second, other foundation types should be used. (Ord. 1-04-10 § 1)

15.16.205 Garages and accessory structures.

The standards of construction defined in HCC 15.16.170 apply to all structures built in special flood hazard areas including garages or any accessory structures. Addition of this section to a community’s floodplain management ordinance contains the definition for accessory structures and construction requirements to allow for the permitting of an accessory structure or detached garage within special flood hazard areas without a variance. (Ord. 1-04-10 § 1)