Grass Valley Municipal Code Ch. 15.52 Flood Damage Prevention

The legislature of the State of California has in Government Code Sections 65302, 65560 and 65800 conferred upon local government units authority to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry.

(Ord. 463 § 1 (part), 1991: prior code § 26-1.10)

A. The flood hazard areas of city 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 floodproof, elevated or otherwise protected from flood damage also contribute to the flood loss.

(Ord. 463 § 1 (part), 1991: prior code § 26-1.20)

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:

A. To protect human life and health;

B. To minimize expenditure of public money for costly flood control projects;

C. To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

D. To minimize prolonged business interruptions;

E. To minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, streets and bridges located in areas of special flood hazard;

F. To 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. To ensure that potential buyers are notified that property is in an area of special flood hazard; and

H. To ensure that those who occupy the areas of special flood hazard assume responsibility for their actions.

(Ord. 463 § 1 (part), 1991: prior code § 26-1.30)

In order to accomplish its purposes, 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 flood heights or velocities;

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

C. Controlling the alteration of the natural floodplain, stream channels, and natural protective barriers, which help accommodate or channel floodwaters;

D. Controlling fill, 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. 463 § 1 (part), 1991: prior code § 26-1.40)

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

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

"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.

"Alluvial fan" means a geomorphologic feature characterized by a cone or fan-shaped deposit of boulders, gravel, and fine sediments that have been eroded from mountain slopes, transported by flood flows, and then deposited on the valley floors, and which is subject to flash flooding, high velocity flows, debris flows, erosion, sediment movement and deposition, and channel migration. "Apex" means the point of highest elevation on an alluvial fan, which on undisturbed fans is generally the point where the major stream that formed the fan emerges from the mountain front.

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

"Area of shallow flooding" means a designated AO or AH 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.

"Area of special flood hazard." See "special flood hazard area."

"Area of special mudslide (i.e., mudflows) hazard" is the area subject to severe mudslides (i.e., mudflows). The area is designated as zone M on the Flood Insurance Rate Map (FIRM).

"Area of special flood-related erosion hazard" is the land within a community which is most likely to be subject to severe flood-related erosion losses. The area may be designated as zone E on the Flood Insurance Rate Map (FIRM).

"Backfill" means the placement of fill material within a specified depression, hole or excavation pit below the surrounding adjacent ground level as a means of improving floodwater conveyance or to restore the land to the natural contours existing prior to excavation.

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

"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").

"Building." See "structure."

"City" means the City of Grass Valley.

"Critical feature" means an integral and readily identifiable part of a flood protection system, without which the flood protection provided by the entire system would be compromised.

"Curvilinear line" means the border on either a Flood Hazard Boundary Map or Flood Insurance Rate Map that delineates the special flood, mudslide (i.e., mudflow) and/or flood-related erosion hazard areas and consists of a curved or contour line that follows the topography.

"Development" means any manmade change to improved or unimproved real estate, including but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials.

"Encroachment" means the advance or infringement of uses, plant growth, fill, excavation, buildings, permanent structures or development into a floodplain which may impede or alter the flow capacity of a floodplain.

"Erosion" means the process of the gradual wearing away of land masses. This peril is not per se covered under the National Flood Insurance Program.

"Existing manufactured home park or subdivision" means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before the effective date of the floodplain management regulations adopted by a community.

"Expansion to an existing manufactured home park or subdivision" means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).

"Fill" is the placement of fill material at a specified location to bring the ground surface up to a desired elevation.

"Fill material" can be natural sand, dirt, soil or rock. For the purposes of floodplain management, fill material may include concrete, cement, soil cement, brick or similar material as approved on a case by case basis.

"Flood elevation determination" means a determination by the administrator of the water surface elevations of the base flood, that is, the flood level that has a one percent or greater chance of occurrence in any given year.

"Flood elevation study" means an examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation and determination of mudslide (i.e., mudflow) and/or flood-related erosion hazards.

"Flood," "flooding" or "floodwater" means:

1. A general and temporary condition of partial or complete inundation of normally dry land areas from:

a. The overflow of inland or tidal waters,

b. The unusual and rapid accumulation or runoff of surface waters from any source, and/or

c. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in paragraph (b) of this definition and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current; and

2. The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an 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 paragraph (a) of this definition.

"Flood Hazard Boundary Map (FHBM)" means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated the areas of flood hazards.

"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.

"Flood Insurance Study" means the official report provided by the Federal Insurance Administration that includes flood profiles, the Flood Insurance Rate Map, the Flood Boundary and Floodway Map, and the water surface elevation of the base flood.

"Floodplain" or "flood-prone area" means any land area susceptible to being inundated by water from any source. See definition of "flooding."

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

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

"Floodplain management regulations" means zoning ordinances, subdivision regulations, building codes, health regulations and special purpose ordinances such as floodplain management regulations.

"Flood protection system" means those physical structural works for which funds have been authorized, appropriated, and expended and which have been constructed specifically to modify flooding in order to reduce the extent of the area within a community subject to a "special flood hazard" and the extent of the depths of associated flooding. Such a system typically includes hurricane tidal barriers, dams, reservoirs, levees or dikes. These specialized flood-modifying works are those constructed to conform with sound engineering standards.

"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.

"Flood-related erosion" means the collapse or subsidence of land along the shore of a lake or other body of water as a result of 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 a flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding.

"Flood-related erosion area" or "flood-related erosion-prone area" means a land area adjoining the shore of a lake or other body of water, which due to the composition of the shoreline or bank and high water levels or wind-driven currents, is likely to suffer flood-related erosion damage.

"Flood-related erosion area management" means the operation of an overall program of corrective and preventive measures for reducing flood-related erosion damage, including but not limited to, emergency preparedness plans, flood-related erosion control works, and floodplain management regulations.

"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; also referred to as "regulatory floodway."

"Floodway encroachment lines" means the lines marking the limits of floodways on federal, state and local floodplain maps.

"Floodway fringe" is the area of a floodplain on either side of the designated floodway where encroachment may be permitted.

"Fraud and victimization," related to Sections 15.52.230 through 15.52.250 of this chapter, means that the variance granted must not cause fraud on, nor victimization, of the public. In examining this requirement, the variance board 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 that are 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. In addition, future owners may purchase the property, unaware that it is subject to potential flood damage, and can be insured only at very high flood insurance rates.

"Freeboard" means a factor 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 a 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 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.

"Hardship," related to Sections 15.52.230 through 15.52.250 of this chapter, means the hardship that would result from a failure to grant the requested variance. The variance board requires that the variance be exceptional, unusual, and peculiar to the property involved. Mere economic or financial hardship alone is not exceptional. Inconvenience, aesthetic considerations, physical handicaps, personal preferences, or the disapproval of ones neighbors likewise cannot, as a rule, qualify as exceptional hardships. All of these problems can be resolved through other means, without granting a variance. This is so even if the alternative means are more expensive or complicated than building with a variance, or if they require the property owner to put the parcel to a different use than originally intended, or to build elsewhere.

"Highest adjacent grade" means the highest natural elevation of the 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 registered historic district;

3. Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of Interior; or

4. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either:

a. By an approved state program as determined by the Secretary of the Interior, or

b. By the Secretary of the Interior directly in states with approved programs.

"Landfill" means a permitted location for the disposal, placement or dumping of garbage, trash, debris, junk or waste material.

"Levee" means a manmade structure, usually an earthen embankment, design 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 any 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.

"Manufactured home" means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when attached to the required utilities. The term "manufactured home" does not include a "recreational vehicle."

"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.

"Map" means the Flood Hazard Boundary Map (FHBM) or the Flood Insurance Rate Map (FIRM) for a community, issued by the Flood Insurance Administration of the Federal Emergency Management Agency.

"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.

"Minimum necessary," related to Sections 15.52.230 through 15.52.250 of this chapter means the minimum necessary to afford relief to the applicant of a variance with a minimum deviation from the requirements of this chapter. In the case of variances to an elevation requirement, this means the variance board need not grant permission for the applicant to build at grade, for example, or even to whatever elevation the applicant proposes, but only that level the board believes will both provide relief and preserve the integrity of the local ordinance.

"Mudslide" (i.e., mudflow) describes a condition where there is a river, flow or inundation of liquid mud down a hillside usually as a result of a dual condition of loss of brush cover, and the subsequent accumulation of water on the ground preceded by a period of unusually heavy or sustained rain.

"Mudslide-prone area" (i.e., mudflow-prone) means an area with land surfaces and slopes of unconsolidated material where the history, geology and climate indicate a potential for mudflow.

"New construction" means structures for which the start of construction commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures.

"New manufactured home park or subdivision" means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after the effective date of floodplain management regulations adopted by a community.

"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" means a flood which has a one percent annual probability of being equalled or exceeded. It is identical to the "base flood," which will be the term used throughout this chapter.

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

"Public safety and nuisances," related to Sections 15.52.230 through 15.52.250 of this chapter means the granting of a variance must not result in additional threats to public safety or create nuisances. This chapter is intended to help protect the health, safety, well-being, and property of the local citizens. This is a long-range community effort made up of a combination of approaches such as adequate drainage systems, warning and evacuation plans, and keeping new property above the flood levels. These long-term goals can only be met if exceptions to the requirements of this chapter are kept to a bare minimum.

"Recreational vehicle" means a vehicle which is:

1. Built on a single chassis;

2. Four hundred square feet or fewer when measured at the largest horizontal projection;

3. Designed to be self-propelled or permanently towable by a light duty truck; and

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

"Regulatory floodway" means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.

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

"Sheet flow area." See "area of shallow flooding."

"Special flood hazard area (SFHA)" means an area having special flood or flood-related erosion hazards, and shown on a FHBM or FIRM as zone A, AO, A1-A30, AE, A99 or AH.

"Start of construction" includes substantial improvement and other proposed new development and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within one hundred eighty 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.

"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.

"Substantial damage" means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed fifty percent of the market value of the structure before the damage occurred.

"Substantial improvement" means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 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. The term does not, however, include either:

1. Any project for improvement of a structure to correct existing violations or state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions, or

2. Any alteration of an "historic structure," provided that the alteration will not preclude the structure's continued designation as an "historic structure."

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

"Water surface elevation" means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929 (or other datum, where specified) of floods of various magnitudes and frequencies in the floodplain 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. 463 § 1 (part), 1991: prior code §§ 26-2.10 and 26-4.20 (part))

This chapter shall apply to all areas of special flood hazards, areas of flood-related erosion hazards and areas of mudslide (i.e., mudflow) hazards within the jurisdiction of city.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.10)

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 dated August 19, 1991, and the Flood Insurance Rate Map (FIRM), dated August 19, 1991, and all subsequent amendments and/or revisions, are hereby adopted by reference and declared to be a part of this chapter. The Flood Insurance Study 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 are recommended to the city council by the floodplain administrator. The study and Flood Insurance Rate Maps (FIRMs) are on file in the office of the city engineer, City Hall, 125 E. Main Street, Grass Valley, CA 95945.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.20)

A. No structure or land shall after the effective date of the ordinance codified in this chapter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor.

B. Nothing in this section shall prevent the city council from taking such lawful action as is necessary to prevent or remedy any violation.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.30)

This chapter is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this chapter and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.40)

In the interpretation and application of this chapter, all provisions shall be:

A. Considered as minimum requirements;

B. Liberally construed in favor of the governing body; and

C. Deemed neither to limit nor repeal any other powers granted under state statutes.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.50)

A. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood hazards, areas of flood-related erosion hazards and areas of mudslide (i.e., mudflow) hazards or uses permitted within such areas will be free from flooding or flood damages.

B. This chapter shall not create liability on the part of city council, any officer or employee thereof, or the Federal Insurance Administration of the Federal Emergency Management Agency, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made thereunder.

(Ord. 463 § 1 (part), 1991: prior code § 26-3.60)

A. A development permit shall be obtained before any construction or other development begins within any area of special flood hazard, areas of flood-related erosion hazard or areas of mudslide (i.e., mudflow) established in Section 15.52.070.

B. Application for a development permit shall be made on forms furnished by the 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 same.

C. Specifically, the following information is required in the application:

1. Proposed elevation in relation to mean sea level, 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 mean sea level to which any structure will be floodproof;

3. All appropriate certifications listed in Section 15.52.140D. of this chapter; and

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

(Ord. 463 § 1 (part), 1991: prior code § 26-4.10)

The city engineer is hereby appointed to administer and implement this chapter by granting or denying development permits in accord with its provisions.

(Ord. 463 § 1 (part), 1991: prior code § 26-4.20)

The duties and responsibilities of the floodplain administrator shall include, but not be limited to:

A. Permit Review. Review all development permits to determine:

1. That the permit requirements of this chapter have been satisfied;

2. That all other required state and federal permits have been obtained;

3. That the site is reasonably safe from flooding; and

4. That the proposed development does not adversely affect the carrying capacity of areas where base flood elevations have been determined but a floodway has not been designated.

B. Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 15.52.070, the floodplain administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal or state agency, or other source, in order to administer Sections 15.52.150 through 15.52.220 of this chapter. Any such information shall be submitted to the city council for adoption.

C. Whenever a watercourse is to be altered or relocated the administrator shall:

1. Notify adjacent communities and the California Department of Water Resources prior to such alternation or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration of the Federal Emergency Management Agency;

2. Require that the flood-carrying capacity of the altered or relocated portion of the watercourse is maintained.

D. Obtain and maintain for public inspection and make available as needed:

1. The certification required by Section 15.52.150C.1., floor elevations;

2. The certification required by Section 15.52.150C.2., elevations in areas of shallow flooding;

3. The certification required by Section 15.52.150C.3., elevation or floodproofing of nonresidential structures;

4. The certification required by Section 15.52.150C.1.a. or b., wet floodproofing standard;

5. The certification of elevation required by Section 15.52.170B., subdivision standards;

6. The certification required by Section 15.52.200A., floodway encroachments;

7. The reports required by Section 15.52.210D., mudflow standards.

E. Make interpretations, where needed, as to the exact location of the boundaries of the areas of special flood hazards, areas of flood-related erosion hazards or areas of mudslide (i.e., mudflow). 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 15.52.240.

F. Take action to remedy violations of this chapter as specified in Section 15.52.080 of this chapter.

(Ord. 463 § 1 (part), 1991: prior code § 26-4.30)

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

A. Anchoring.

1. All new construction, substantial improvements, and other proposed new development 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 Section 15.52.180.

B. Construction Materials and Methods.

1. All new construction, substantial improvement and other proposed new development shall be constructed with materials and utility equipment resistant to flood damage;

2. All new construction, substantial improvement and other proposed new development shall be constructed using methods and practices that minimize flood damage;

3. All new construction, substantial improvement and other proposed new development 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 AH or AO that adequate drainage paths around structures on slopes guide floodwaters around and away from proposed structures.

C. Elevation and Floodproofing.

1. New construction, substantial improvement and other proposed new development shall have the lowest floor, including basement, elevated to or above the base flood elevation. Nonresidential structures may meet the standards in subdivision 3 of this subsection. Upon the completion of the structure the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, or verified to be properly elevated by the community building inspector. Such certification or verification shall be provided to the floodplain administrator;

2. New construction, substantial improvement, and other proposed new development in zone AO shall have the lowest floor, including basement, elevated above the highest adjacent grade 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 subdivision 3 of this subsection. Upon the completion of the structure the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, or verified to be properly elevated by the community building inspector. Such certification or verification shall be provided to the floodplain administrator.

3. Nonresidential construction shall either be elevated to conform with subdivision 1 or 2 of this subsection or together with attendant utility and sanitary facilities:

a. Be floodproof 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, and

c. Be certified by a registered professional 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, substantial improvement and other proposed new development, that fully-enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or meet or exceed the following minimum criteria:

a. 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 floodwater), or

b. Be certified to comply with a local floodproofing standard approved by the Federal Insurance Administration of the Federal Emergency Management Agency.

5. Manufactured homes shall also meet the standards in Section 15.52.180.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.10)

A. All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and 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.

C. Other utilities are addressed in Sections 15.52.150B. and 15.52.170D.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.20)

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 structure(s) and pad(s). If the site is filled above the base flood elevation, the final pad elevation shall be certified by a registered professional engineer or 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 public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.

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

(Ord. 463 § 1 (part), 1991: prior code § 26-5.30)

A. All manufactured homes that are placed or substantially improved within a special flood hazard area on the community's flood insurance rate map (1) outside of a 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, (4) in an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as the result of a flood will be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be secured to an adequately anchored foundation system to resist flotation collapse and lateral movement.

B. All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision on the community's flood insurance rate map that are not subject to the provisions of subsection A of this section will be elevated so that either:

1. The lowest floor of the manufactured home is at, or above, the base flood elevation, 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 be secured to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.40)

All recreational vehicles placed on sites within a floodplain shown on the community's Flood Insurance Rate Map will either:

A. Be on the site for fewer than one hundred eighty consecutive days,

B. Be fully licensed and ready for highway use, or

C. Meet the permit requirements of Sections 15.52.120 through 15.52.140 of this chapter and the elevation and anchoring requirements for manufactured homes in Section 15.52.180 of this chapter.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.50)

Located within areas of special flood hazard established in Section 15.52.070 of 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. Prohibition of encroachments, including fill, new construction, substantial improvement, and other new development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.

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

(Ord. 463 § 1 (part), 1991: prior code § 26-5.60)

A. The floodplain administrator shall review permits for proposed construction of other development to determine if it is proposed within a mudslide area.

B. Permits shall be reviewed to determine that the proposed development is reasonably safe from mudslide hazards. Factors to be considered in making this determination include but are not limited to:

1. The type and quality of soils;

2. Evidence of groundwater or surface water problems;

3. The depth and quality of any fill;

4. The overall slope of the site; and

5. The weight that any proposed development will impose on the slope.

C. Within areas which have mudslide hazards, the following requirements apply:

1. A site investigation and further review shall be made by persons qualified in geology and soils engineering;

2. The proposed grading, excavation, new construction, substantial improvement and other proposed new development shall be adequately designed and protected against mudslide damages;

3. The proposed grading, excavations, new construction, substantial improvement and other proposed new development do not aggravate the existing hazard by creating either on-site or off-site disturbances; and

4. Drainage, planting, watering and maintenance shall not endanger slope stability.

D. Within zone M on the flood insurance rate map, the city shall adopt a drainage ordinance which at least complies with the standards of Sections 7001 through 7006 and Sections 7008 through 7015 of the most recent amendment of the 1973 Uniform Building Code:

1. The location of foundation and utility systems of new construction, substantial improvement and other proposed new development;

2. The location, drainage and maintenance of all excavations, cuts and fills and planted slopes;

3. Protective measures, including but not limited to, retaining walls, buttress fills, subdrains, diverter terraces, benchings, etc.; and

4. Engineering drawings and specifications to be submitted for all corrective measures, accompanied by supporting soils engineering and geology reports.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.70)

A. The floodplain administrator shall require permits for proposed construction and other development within all flood-related erosion-prone areas as known to the city.

B. Such permits shall be reviewed to determine whether the proposed site alterations and improvements will be reasonably safe from flood-related erosion and will not cause flood-related erosion hazards or otherwise aggravate the existing hazard.

C. If a proposed improvement is found to be in the path of flood-related erosion or would increase the erosion hazard, such improvement shall be relocated or adequate protective measures shall be taken to avoid aggravating the existing erosion hazard.

D. Within zone E on the flood insurance rate map, a setback is required for all new development from the ocean, lake, bay, riverfront or other body of water to create a safety buffer consisting of a natural vegetative or contour strip. This buffer shall be designated according to the flood-related erosion hazard and erosion rate, in relation to the anticipated "useful life" of structures, and depending upon the geologic, hydrologic, topographic and climatic characteristics of the land. The buffer may be used for suitable open space purposes, such as for agricultural, forestry, outdoor recreation and wildlife habitat areas, and for other activities using temporary and portable structures only.

(Ord. 463 § 1 (part), 1991: prior code § 26-5.80)

The variance criteria set forth in this section are based on the general principle of zoning law that variances pertain to a piece of property and are not personal in nature. Though these standards vary from jurisdiction to jurisdiction, in general, a properly-issued variance is 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 the city council 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. Therefore, the variance guidelines provided in this chapter 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.

(Ord. 463 § 1 (part), 1991: prior code § 26-6.10)

A. The city council shall hear and decide appeals and requests for variances from the requirements of this chapter.

B. The city council 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.

C. In passing upon such applications, the city council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:

1. The danger that materials may be swept onto other lands to the injury of others;

2. The danger to life and property due to flooding or erosion damage;

3. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the existing individual owner and future owners of the property;

4. The importance of the services provided by the proposed facility to the city;

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

6. The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

7. The compatibility of the proposed use with existing and anticipated development;

8. The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;

9. The safety of access to the property in time of flood for ordinary and emergency vehicles;

10. The expected heights, velocity, duration, rate of rise, and sediment transport of the floodwaters expected at the site; and,

11. 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.

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

1. 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, and

2. Such construction below the base flood level increases risks to life and property. A copy of the notice shall be recorded by the floodplain board in the office of the Nevada County recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

E. 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 of the Federal Emergency Management Agency.

(Ord. 463 § 1 (part), 1991: prior code § 26-6.20)

A. Generally, variances may be issued for new construction, substantial improvement and other proposed new development 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 that the procedures of Sections 15.52.120 through 15.52.220 of this chapter have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases.

B. Variances may be issued for the repair or rehabilitation of "historic structures" (as defined in Section 15.52.050 of this chapter) 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.

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

D. Variances shall only be issued upon a determination that the variance is the "minimum necessary" (as defined in Section 15.52.050 of this chapter), considering the flood hazard, to afford relief.

E. Variances shall only be issued upon:

1. A showing of good and sufficient cause;

2. A determination that failure to grant the variance would result in exceptional "hardship" (as defined in Section 15.52.050 of this chapter) to the applicant; and

3. 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 Section 15.52.050 of this chapter), cause "fraud or victimization" (as defined in Section 15.52.050 of this chapter) of the public, or conflict with existing local laws or ordinances.

F. 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 subsections A through E 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.

G. Upon consideration of the factors of Section 15.52.240C and the purposes of this chapter, the city council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

(Ord. 463 § 1 (part), 1991: prior code § 26-6.30)