Chapter 15.80
FLOODPLAIN MANAGEMENT

Sections:

15.80.010    Statutory authorization, findings of fact, purpose and methods.

15.80.020    Definitions.

15.80.030    General provisions.

15.80.040    Administration.

15.80.050    Provisions for flood hazard reduction.

15.80.060    Variance procedure.

15.80.010 Statutory authorization, findings of fact, purpose and methods.

A. Statutory Authorization. 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. Therefore, the city council of the city of Pittsburg does adopt the following floodplain management regulations.

B. Findings of Fact.

1. The flood hazard areas of the city of Pittsburg 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.

2. These flood losses are caused by uses that are inadequately elevated, floodproofed or protected from flood damage. The cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities also contribute to the flood loss.

C. 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:

1. Protect human life and health;

2. Minimize expenditure of public money for costly flood control projects;

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

4. Minimize prolonged business interruptions;

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

6. Help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future blighted areas caused by flood damage;

7. Ensure that potential buyers are notified that property is in an area of special flood hazard; and

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

D. Methods of Reducing Flood Losses. In order to accomplish its purposes, this chapter includes methods and provisions to:

1. Restrict or prohibit 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;

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

3. Control the alteration of natural floodplains, stream channels and natural protective barriers, which help accommodate or channel floodwaters;

4. Control filling, grading, dredging and other development which may increase flood damage; and

5. Prevent or regulate the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards in other areas. [Ord. 1163 § 1, 1999.]

15.80.020 Definitions.

Unless specifically defined in this section, 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.

“Appeal” means a request for a review of the floodplain administrator’s interpretation of any provision of this chapter.

“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 (SFHA).”

“Base flood” means a flood which has a one percent chance of being equaled or exceeded in any given year (also called the “100-year flood”). Base flood is the term used throughout this chapter.

“Basement” means any area of the building having its floor subgrade, i.e., below ground level on all sides.

“Building.” See “Structure.”

“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.

“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 pouting 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).

“Flood,” “flooding,” or “flood water” means a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters, or the unusual and rapid accumulation or runoff of surface waters from any source.

“Flood boundary and floodway map (FBFM)” 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 floodway.

“Flood hazard boundary map” 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 “Flooding.”

“Floodplain administrator” means 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 and preserving and enhancing, where possible, natural resources in the floodplain, including but not limited to emergency preparedness plans, flood control works, floodplain management regulations, and open space plans.

“Floodplain management regulations” means this chapter and other zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as grading and erosion control) and other application of police power which control development in flood-prone areas. This term describes federal, state or local regulations in any combination thereof, which provide standards for preventing and reducing flood loss and damage.

“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 1-93, 3-93, and 7-93 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 more than one foot. Also referred to as “regulatory floodway.”

“Floodway fringe” is that area of the floodplain on either side of the “regulatory floodway” where encroachment may be permitted.

“Fraud and victimization” as related to PMC 15.80.060, Variance procedure, means that the variance granted must not cause fraud on or victimization of the public. In examining this requirement, the city council will consider the fact that every newly constructed building adds to government responsibilities and remains a part of the community for 50 to 100 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.

“Functionally dependent use” means a use, which cannot perform its intended purpose unless it is located or carded 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, and does not include long-term storage or related manufacturing facilities.

“Governing body” means the city council of the city of Pittsburg that is empowered to adopt and implement regulations to provide for the public health, safety and general welfare of its citizenry.

“Hardship” as related to PMC 15.80.060, Variance procedure, means the exceptional hardship that would result from a failure to grant the requested variance. The city council 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 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 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 Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;

2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;

3. Individually listed on a State Inventory of Historic Places in states with historic preservation programs which have been approved by the Secretary of Interior; or

4. Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either by an approved state program as determined by the Secretary of the Interior or directly by the Secretary of the Interior in states without approved programs.

“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 accord with sound engineering practices.

“Lowest floor” means the lowest floor of the lowest enclosed area, including basement (see “Basement” definition).

1. An unfinished or flood-resistant enclosure below the lowest floor that is 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, it conforms to applicable nonelevation design requirements, including, but not limited to:

a. The wet floodproofing standard in PMC 15.80.050(A)(3)(c);

b. The anchoring standards in PMC 15.80.050(A)(1);

c. The construction materials and methods standards in PMC 15.80.050(A)(2); and

d. The standards for utilities in PMC 15.80.050(B).

2. For residential structures, all subgrade enclosed areas are prohibited as they are considered to be basements (see “Basement” definition). This prohibition includes below-grade garages and storage areas.

“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.

“Market value” shall be determined by estimating the cost to replace the structure in new condition and adjusting that cost figure by the amount of depreciation which has accrued since the structure was constructed. The cost of replacement of the structure shall be based on a square foot cost factor determined by reference to a building cost estimating guide recognized by the building construction industry. The amount of depreciation shall be determined by taking into account the age and physical deterioration of the structure and functional obsolescence as approved by the floodplain administrator, but shall not include economic or other forms of external obsolescence. Use of replacement costs or accrued depreciation factors different from those contained in recognized building cost estimating guides may be considered only if such factors are included in a report prepared by an independent professional appraiser and supported by a written explanation of the differences.

“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.

“New construction,” for floodplain management purposes, means structures for which the “start of construction” commenced on or after the effective date of floodplain management regulations adopted by this community, and includes any subsequent improvements to such structures.

“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 this 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” or “100-year flood.” See “Base flood.”

“Public safety and nuisance” as related to PMC 15.80.060, Variance procedure, means that the granting of a variance must not result in anything which is injurious to safety or health of an entire community or neighborhood, or any considerable 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, which is:

1. Built on a single chassis;

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

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

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

“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 one foot.

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

“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 in the floodplain subject to a one percent or greater chance of flooding in any given year. It is shown on an 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 180 days from the date of the permit. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation; or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

“Structure” means a walled and roofed building that is principally aboveground; this includes a gas or liquid storage tank or 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 50 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 50 percent of the market value of the structure before the “start of construction” of the improvement. This term includes structures which have incurred “substantial damage,” regardless of the actual repair work performed. The term does not, however, include:

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

“Violation” means the failure of a structure or other development to be fully compliant with this chapter. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this chapter is presumed to be in violation until such time as that documentation is provided.

“Water surface elevation” means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929, (or other datum, where specified) of floods of various magnitudes and frequencies in the floodplains of coastal 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. 1163 § 1, 1999.]

15.80.030 General provisions.

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

B. Basis for Establishing the Areas of Special Flood Hazard. 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 July 2, 1987, accompanying flood insurance rate maps (FIRMs), and all subsequent amendments and/or revisions, are adopted by reference and declared to be a part of this chapter. This 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 are recommended to the city council of the city of Pittsburg by the floodplain administrator. The study and FIRMs are on file at City Hall, 65 Civic Avenue.

C. Compliance. No structure or land shall hereafter be constructed, located, extended, converted or altered without full compliance with the term of this chapter and other applicable regulations. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Nothing herein shall prevent the city of Pittsburg from taking such lawful action as is necessary to prevent or remedy any violation.

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

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

1. Considered as minimum requirements;

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

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

F. Warning and Disclaimer of Liability. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on 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 or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the city of Pittsburg, any officer or employee thereof, the state of California, or the Federal Insurance Administration, Federal Emergency Management Agency, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder.

G. Severability. This chapter and the various parts thereof are declared to be severable. Should any section of this chapter be declared by the courts to be unconstitutional or invalid, such decision shall not affect the validity of the chapter as a whole, or any portion thereof other than the section so declared to be unconstitutional or invalid. [Ord. 1163 § 1, 1999.]

15.80.040 Administration.

A. Establishment of Development Permit. A development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in PMC 15.80.030(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 foregoing. Specifically, the following information is required.

1. Site plan shall include but not be limited to:

a. For all proposed structures, spot ground elevations at building corners and 20-foot (or smaller) intervals along the foundation footprint, or one-foot contour elevations throughout the building site;

b. Proposed locations of water supply, sanitary sewer and utilities;

c. If available, the base flood elevation from the flood insurance study and/or flood insurance rate map; and

d. If applicable, the location of the regulatory floodway;

2. Foundation design detail shall include but not be limited to:

a. Proposed elevation in relation to mean sea level of the lowest floor (including basement) of all structures;

b. For a crawl-space foundation, location and total net area of foundation openings as required in PMC 15.80.050(A)(3)(c) and FEMA Technical Bulletins 1-93 and 7-93; and

c. For foundations placed on fill, the location and height of fill, and compaction requirements (compacted to 95 percent using the Standard Proctor Test method); and

3. Proposed elevation in relation to mean sea level to which any nonresidential structure will be floodproofed, as required in PMC 15.80.050(A) (3)(b) and FEMA Technical Bulletin 3-93; and

4. All appropriate certifications listed in subsection (C)(4) of this section; and

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

B. Designation of the Floodplain Administrator. The city engineer is appointed to administer, implement, and enforce this chapter by granting or denying development permits in accord with its provisions.

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

1. Permit Review. Review all development permits to determine that:

a. The permit requirements of this chapter have been satisfied;

b. All other required state and federal permits have been obtained;

c. The site is reasonably safe from flooding; and

d. 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. For purposes of this chapter, “adversely affects” means that the cumulative effect of the proposed development when combined with all other existing and anticipated development will increase the water surface elevation of the base flood more than one foot at any point.

2. Review, Use and Development of Other Base Flood Data.

a. When base flood elevation data has not been provided in accordance with PMC 15.80.030(B), 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 PMC 15.80.050. Any such information shall be submitted to the city council for adoption; or

b. If no base flood elevation data is available from a federal or state agency or other source, then a base flood elevation shall be obtained using one of two methods from the FEMA publication “Managing Floodplain Development in Approximate Zone A Areas – A Guide for Obtaining and Developing Base (100-Year) Flood Elevations” dated July 1995 in order to administer PMC 15.80.050:

i. Simplified Method.

(A) One-hundred-year or base flood discharge shall be obtained using the appropriate regression equation found in a U.S. Geological Survey publication, or the discharge-drainage area method; and

(B) Base flood elevation shall be obtained using the Quick-2 computer program developed by FEMA; or

ii. Detailed Method.

(A) One-hundred-year or base flood discharge shall be obtained using the U.S. Army Corps of Engineers’ HEC-HMS computer program; and

(B) Base flood elevation shall be obtained using the U.S. Army Corps of Engineers’ HEC-RAS computer program.

3. Notification of Other Agencies. In alteration or relocation of a watercourse:

a. Notify adjacent communities and the California Department of Water Resources prior to alteration or relocation;

b. Submit evidence of such notification to the Federal Insurance Administration, Federal Emergency Management Agency; and

c. Assure that the flood carrying capacity within the altered or relocated portion of such watercourse is maintained.

4. Documentation of Floodplain Development. Obtain and maintain for public inspection and make available, as needed, the following:

a. Certification required by PMC 15.80.050(A)(3)(a) and (D) (lowest floor elevations);

b. Certification required by PMC 15.80.050(A)(3)(b) (elevation or floodproofing of nonresidential structures);

c. Certification required by PMC 15.80.050(A)(3)(c) (wet floodproofing standard);

d. Certification of elevation required by PMC 15.80.050(C)(2) (subdivision standards); and

e. Certification required by PMC 15.80.050(F)(1) (floodway encroachments).

5. Map Determinations. Make interpretations, where needed, as to the exact location of the boundaries of the areas of special flood hazard. Where there appears to be a conflict between a mapped boundary and actual field conditions, grade and base flood elevations shall be used to determine the boundaries of the special flood hazard area. The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in PMC 15.80.060.

6. Remedial Action. Take action to remedy violations of this chapter as specified in PMC 15.80.030(C).

D. Appeals. The city council of the city of Pittsburg 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. 1163 § 1, 1999.]

15.80.050 Provisions for flood hazard reduction.

A. Standards of Construction. In all areas of special flood hazards the following standards are required:

1. Anchoring.

a. 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.

b. All manufactured homes shall meet the anchoring standards of PMC 15.80.040.

2. Construction Materials and Methods. All new construction and substantial improvement shall be constructed:

a. With flood resistant materials as specified in FEMA Technical Bulletin TB 2-93 and utility equipment resistant to flood damage;

b. Using methods and practices that minimize flood damage;

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

d. Within zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.

3. Elevation and Floodproofing. (See PMC 15.80.020, Definitions, for “basement,” “lowest floor,” “new construction,” “substantial damage” and “substantial improvement.”)

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

i. In an AO zone, elevated above the highest adjacent grade to a height exceeding the depth number specified in feet on the FIRM at least two feet or elevated at least four feet above the highest adjacent grade if no depth number is specified;

ii. In an A zone, elevated at least two feet above the base flood elevation; said base flood elevation shall be determined by one of the methods in PMC 15.80.040(C)(2);

iii. In all other zones, elevated at least two feet above the base flood elevation.

Upon the 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 community building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.

b. Nonresidential construction, new or substantial improvement, shall either be elevated to conform with subsection (A)(3)(a) of this section, or together with attendant utility and sanitary facilities:

i. Be floodproofed below the elevation recommended under subsection (A)(3)(a) of this section, so that the structure is watertight with walls substantially impermeable to the passage of water;

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

iii. Be certified by a registered professional engineer or architect that the standards of this section (subsection (A)(3)(b) of this section) are satisfied. Such certification shall be provided to the floodplain administrator.

c. All new construction and substantial improvement with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement shall follow the guidelines in FEMA Technical Bulletins TB 1-93 and TB 7-93, and must exceed the following minimum criteria:

i. Have 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. 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

ii. Be certified by a registered professional engineer or architect.

d. Manufactured homes shall also meet the standards in subsection (D) of this section.

B. Standards for Utilities.

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

a. Infiltration of flood waters into the systems, and

b. Discharge from the systems into floodwaters.

2. On-site waste disposal systems shall be located to avoid impairment to them, or contamination from them during flooding.

C. Standards for Subdivisions.

1. All preliminary subdivision proposals shall identify the special flood hazard area and the elevation of the base flood.

2. All subdivision plans will provide the elevation of proposed structure(s) and pad(s). If the site is filled above the base flood elevation, the lowest floor and pad elevations shall be certified by a registered professional engineer or surveyor and provided to the floodplain administrator.

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

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

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

D. Standards for Manufactured Homes.

1. All manufactured homes that are placed or substantially improved, within Zones A1-30, AH and AE on the community’s flood insurance rate map, on sites located:

a. Outside of a manufactured home park or subdivision,

b. In a new manufactured home park or subdivision,

c. In an expansion to an existing manufactured home park or subdivision, or

d. In an existing manufactured home park or subdivision on a site upon which a manufactured home has incurred “substantial damage” as the result of a flood shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated at least two feet above the base flood elevation and be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

2. All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-30, AH and AE on the community’s flood insurance rate map that are not subject to the provisions of subsection (D)(1) of this section will be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, and be elevated so that either the:

a. Lowest floor of the manufactured home is at least two feet above the base flood elevation, or

b. Manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade.

Upon the 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 community building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.

E. Standards for Recreational Vehicles. All recreational vehicles placed on sites within Zones A1-30, AH and AE on the community’s flood insurance rate map will either:

1. Be on the site for fewer than 180 consecutive days, and be fully licensed and ready for highway use; a recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions; or

2. Meet the permit requirements of PMC 15.80.040 and the elevation and anchoring requirements for manufactured homes in subsection (D) (1) of this section.

F. Floodways. Located within areas of special flood hazard established in PMC 15.80.030(B) 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.

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

2. If subsection (F)(1) of this section is satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of this section. [Ord. 1163 § 1, 1999.]

15.80.060 Variance procedure.

A. Nature of Variances.

1. 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. 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.

2. 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 chapter 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 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.

B. Appeal Board.

1. In passing upon requests for variances, the city council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and the:

a. Danger that materials may be swept onto other lands to the injury of others;

b. Danger of life and property due to flooding or erosion damage;

c. 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;

d. Importance of the services provided by the proposed facility to the community;

e. Necessity to the facility of a waterfront location, where applicable;

f. Availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

g. Compatibility of the proposed use with existing and anticipated development;

h. Relationship of the proposed use to the comprehensive plan and floodplain management program for that area;

i. Safety of access to the property in time of flood for ordinary and emergency vehicles;

j. Expected heights, velocity, duration, rate of rise and sediment transport of the flood waters expected at the site; and

k. 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.

2. 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 $25.00 for $100.00 of insurance coverage, and

b. Such construction below the base flood level increases risks 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 recorder of the county of Contra Costa and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.

3. 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.

C. Conditions For Variances.

1. 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 PMC 15.80.040 and 15.80.050 have been fully considered. As the lot size increases beyond one-half acre, 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 PMC 15.80.020) upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as a 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 variance is 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 the city council need not grant permission for the applicant to build at grade, or even to whatever elevation the applicant proposes, but only to that elevation which the floodplain administrator 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. Determination that failure to grant the variance would result in exceptional “hardship” (as defined in PMC 15.80.020) to the applicant; and

c. Determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, or extraordinary public expense, create a nuisance (as defined in PMC 15.80.020, see “Public safety and nuisance”), cause fraud or victimization (as defined in PMC 15.80.020) 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 subsection (C)(1) through (5) 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 does not result in additional threats to public safety and does not create a public nuisance.

7. Upon consideration of the factors of subsection (B)(1) of this section 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. 1163 § 1, 1999.]