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HomeMy WebLinkAboutOrd 42-87 Floodplain ORDINANCE NO. 4 2 -87 AN ORDINANCE OF THE CITY OF DUBLIN RELATING TO FLOODPLAIN MANAGEMENT The City Council of the City of Dublin does ordain as follows: SECTION 1.0 FINDINGS OF FACT, PURPOSE AND METHODS 1.1 FINDINGS OF FACT. A. The flood hazard areas of the City of Dublin are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety, and general welfare. B. These flood losses are caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities, and when inadequately anchored, damage uses in other areas. Uses that are inadequately floodproofed, elevated or otherwise protected from flood damage also contribute to the flood loss. 1.2 STATEMENT OF PURPOSE. It is the purpose of this ordinance 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. Page 1 G. To insure that potential buyers are notified that property is ~ in an area of special flood hazard. H. To insure that those who occupy the areas of special flood hazard assume responsibility for 'their actions. 1.3 METHODS OF REDUCING FLOOD LOSSES. In order to accomplish its purposes, this ordinance 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 flood~, including facilities which serve such uses, be Protected against flood damage at the time of initial construction. C. Controlli~ng the alteration of natural flood plains, stream channels, and natural protective barriers, which help accommodate or channel flood waters. D. Controlling filling, grading, dredging, and other development which may increase flood damage. E. Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters or which may increase flood hazards in other areas. SECTION 2.0 DEFINITIONS Unless specifically defined below, words or phrases used in this ordinance shall be interpreted so as to give them the meaning they have in common usage and to give this ordinance its most reasonable application. "Appeal" means a request for a review of the Floodplain Administrator's interpretation of any provision of this ordinance or a request for a variance. "Area of Special Flood Hazard" - See "Special Flood Hazard Area." "Base Flood" means the flood having a one percent chance of being equalled or exceeded in any given year (also called the "100-year flood"). "Basement" means any area of the building having its floor subgrade (below ground level) on all sides. "Breakaway Walls" are any type of walls, whether solid or lattice, and whether constructed of concrete~ masonry, wood, metal, plastic, or any other suitable building material which is not part of the structural support of the building and which is designed to break away under abnormally high tides or wave action without Page 2 causing any damage to the structural integrity of the building on which they are used or any buildings to which they might be carried by flood waters. A breakaway wall shall have a safe design loading resistance of not less than ten and no more than twenty pounds per square foot. Use of breakaway wails must be certified by a registered engineer or architect and shall meet the following conditions: 1. Breakaway wall collapse shall result from a water load less than that which would occur during the base flood. 2. The elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood. "Development" means any man-made change to improved or unimproved real estated, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation, or drilling operations. "Flood or Flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from (1) the overflow of flood waters, (2) the unusual and rapid accumulation or runoff of surface waters from any source, and/or (3) the collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as defined in this definition. "Flood Boundary and Floodway Map" means the official map on which the Federal Insurance Administration has delineated both the areas of flood hazard and the floodway. "Flood Insurance Rate Map (FIRM)" means the official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. "Flood Insurance Study" means the official report' provided by the Federal Insurance Administration that includes flood profiles, the FIRM, 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 Management Regulations" means zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as floodplain ordinance, grading ordinance, and erosion control ordinance) and other applications of police power. The term describes such state or local regulations in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction. Page 3 "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. "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." "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. "Highest Adjacent Grade" means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure. "Lowest Floor" means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor; provided, that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this ordinance. "Manufactured Home" means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term "Manufactured Home" also includes park trailers, travel trailers, and other similar vehicles placed on a site for greater than 180 consecutive days. "Manufactured Home Park or Subdivision" means a parcel (or contiguous parcels) of land divided into two or more manufactured home lots for sale or rent. "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" means, for floodplain management purposes, structures for which the "start of construction" commenced on or after the effective date of a floodplain management regulation adopted by this community. "One Hundred Year Flood" or "100 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 ordinance. "Person" means an individual or his agent, firm, partnership, association or corporation, or agent of the aforementioned groups, or this state or its agencies or political subdivisions. Page 4 "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 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. "Special Flood Hazard Area (SFHA)" means an area having special flood .or flood-related erosion hazards, and shown on an FHBM or FIRM as Zone A, Al-30, AE, A99. "Start of Construction" includes substantial improvement, and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement, or other improvement was within 180 days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the construction of columns, or any work beYond the stage of excavation; or the placement of a manufactured home on a foundation. ~'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. "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 Improvement" means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure either: ~ 1) Before the improvement or repair is started, or 2) If the structure has been damaged, and is being restored, before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. The term does not, however, include either either: 1) Any project for improvement of a structure to comply with existing state or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions; or 2) Any alteration of a structure listed on the National Register of Historic Places or a State Inventory of Historic Places. Page 5 "Variance" means a grant of relief from the requirements of this ordinance which permits construction in a manner that would otherwise be prohibited by this ordinance. "Violation" means the failure of a structure or ~ther development to be fully compliant with the community's floodplain management regulations. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this ordinance is presumed to be in violation until such time as that documentation is provided. SECTION 3.0 GENERAL PROVISIONS 3.1 LANDS TO WHICH THIS ORDINANCE APPLIES. This ordinance shall apply to all areas of special flood hazards, within the jurisdiction of the City of Dublin. 3.2 BASIS FOR ESTABLISHING THE AREAS OF SPECIAL FLOOD HAZARD. The areas of special flood hazard identified by the Federal Emergency Management Agency or the Federal Insurance Administration in a scientific and engineering report entitled "Flood Insurance Study for City of Dublin" dated August 3, 1983, with an accompanying Flood Insurance Rate MaP, is hereby adopted by reference and declared to be a part of this ordinance. This Flood Insurance Study is on file at the City of Dublin Offices, 6500 Dublin Blvd., Dublin, CA 94568. This Flood Insurance Study is the minimum area of ~ applicability of this ordinance and may be supplemented by studies for other areas which allow implementation of this ordinance and which are recommended to the City of Dublin by the Floodplain Administrator. 3.3 COMPLIANCE. No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this ordinance and other applicable regulations. Violations of the provisions of this ordinance by failure to comply with any of its requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Nothing here~n shall prevent the City Council from taking such lawful action as is necessary to prevent or remedy any violation. 3.~. ABROGATION AND GREATER RESTRICTIONS. This ordinance is not intended to repeal, abrogate, or impair any existing easements, covenants, or deed restrictions. However, where this ordinance and another ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail. 3.5 INTERPRETATION. In the interpretation and application of this ordinance, all provisions shall be: A. Considered as minimum requirements. B. Liberally construed in favor of the governing body. C. Deemed neither to limit nor repeal any other powers granted under state statutes. Page 6 3.6 WARNING AND DISCLAIMER OF LIABILITY. The degree of flood protection required by this ordinance 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 man-made or natural causes. This ordinance 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 ordinance shall not create liability on the part of the City of Dublin, any officer or employee thereof, or the Federal Insurance Administration, for any flood damages that result from reliance on this ordinance or any administrative decision lawfully made thereunder. 3.7. SEVERABILITY. This ordinance and the various parts thereof are hereby declared to be severable. Should any section of this ordinance be declared by the courts to be unconstitutional or invalid, such decision shall not affect the validity of the ordinance as a whole, or any portion thereof other than the section so declared to be unconstitutional or invalid. SECTION 4.0 ADMINISTRATION 4.1 ESTABLISHMENT OF DEVELOPMENT PERMIT. A Development Permit shall be obtained before construction or development begins within any area of special flood hazards, established in Section 3.2. Application for a Development Permit shall be made on forms furnished by the Floodplain Administrator any 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: A. Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures. B. Proposed elevation in relation to mean sea level to which any structure will be floodproofed. C. All appropriate certifications listed in Section 4.3D of this ordinance. D. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development. 4.2 DESIGNATION OF THE FLOODPLAIN ADMINISTRATOR. The Building Official is hereby appointed to administer and implement this ordinance by granting or denying development permits in accordance with its provisions. 4.3 DUTIES AND RESPONSIBILITIES OF THE FLOODPLAIN ADMINISTRATOR. The duties and responsibilities of the floodplain administrator shall include, but not be limited to: Page 7 A. Permit Review. 1. Review all development permits to determine that the permit requirements of this ordinance have been satisfied. 2. .All other required state and federal permits have been obtained. 3. The site is reasonably safe from flooding. 4. 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 ordinance, "adversely affects" means that the cumulative effect of the proposed devel6pment when combined with all other existing and anticipated development will not increase the water surface elevation of the base flood more than one foot any point. B. Use of Other Base Flood Data. When base flood elevation data has not been provided in accordance with Section 3.2, the Floodplain Administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a Federal, State, or other source, in order to administer Section 5.0. Any such information shall be submitted to the City Council for adoption. C. Whenever a watercourse is to be altered or relocated: 1. Notify adjacent communities and the California Department of Water Resources prior to such alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Insurance Administration. 2. Require that the flood carrying capacity of the altered or relocated portion of said watercourse is maintained. D. Obtain and maintain for public inspection and make available as needed: 1. The certification required in Section 5.1C.1 (floor elevations). 2. The certification required in Section 5.1.C.2.c. 3. The certification required in Section 5.1.C.3.a. or 5.1.C.3obo 4. The certified elevation required in Section 5.3.B (subdivision standards). 5. The certification required in Section 5.5.A (floodway encroachments). E. Make interpretations where needed, as to the exact location of the boundaries of the areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual Page 8 field conditions). The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in Section 6.0. F. Take action to remedy violations of this ordinance as specified in Section 3.3 herein. SECTION 5.0 PROVISIONS FOR FLOOD HAZARD REDUCTION 5.1 STANDARDS OF CONSTRUCTION. In all areas of special flood hazards the following standards are required: A. Anchoring. 1. Ail new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. 2. Ail manufactured homes'shall meet the anchoring standards of Section 5.4. B. Construction Materials and Methods. 1. Ail new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage. 2. Ail new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage. 3. Ail new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding. C. Elevation and Floodproofing. 1. New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation. Nonresidential structures may meet the standards in Section 5.1.C.3. 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 by the community building inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator. Page 9 2. Nonresidential construction shall either be elevated in conformance with Section 5.1.C.1 or together with attendant utility and sanitary facilities: a. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water. b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. c. Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator. 3. Require, for ail new construction and substantial improvements, that fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered 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 enc].osed area subject to flooding shall be provided. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters, or b. Be certified to comply with a ].ocal floodproofing standard approved by the Federal Insurance Administration. 4. Manufactured homes shall also meet the standards in Section 5.4. 5.2 STANDARDS FOR UTILITIES. A. Ali. new and rep].acement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from systems into flood waters. B. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. Page 10 5.3 STANDARDS FOR SUBDIVISIONS. A. Ail 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 pads. If the site is filled above the base flood, the final pad elevation shall be certified by a registered professional engineer or surveyor and provided to the Floodplain Administrator. C. Ail subdivision proposals shall be consistent with the need to minimize flood damage. D. Ail subdivision proposals shall be consistent ~ith the need to minimize flood damage. E. Ail subdivisions shall provide adequate drainage to reduce exposure to flood hazards. 5.4 STANDARDS FOR MANUFACTURED HOMES. Ail new and replacement manufactured homes and additions to manufactured homes shall: .~ A. Be elevated so that the lowest floor is at or above the base flood elevation. B. Be securely anchored to a permanent foundation system to resist flotation, collapse, or lateral movement. 5.5 FLOODWAYS. Located within areas of special flood hazard established in Section 3.2 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply: .- A. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered 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 Section 5.5.A is satisfied, all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions of Section 5. SECTION 6.0 VARIANCE PROCEDURE 6.1 APPEAL BOARD A. The City Council of the City of Dublin shall hear and decide appeals and requests for variances from the requirements of this ordinance. Page 11 Bo 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 ordinance. C. In passing upon such applications, the City Council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this ordinance, and 1. The danger that materials may be swept onto other lands to the injury of others. 2. The danger of 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 individual owner. 4. The importance of the services provided by the proposed facility to the community. 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 flood waters expected at the site. 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. Page 12 D. Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing items 6.1.C.1 through 6.1.C.11 have been fully considered. As the lot size increases beyond one-half acre, the technical justification required for issuing the variance increases. E. Upon consideration of the factors of Section 6.1.C and the purposes of this ordinance, the City Council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this ordinance. F. The Floodplain Administrator shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration upon request. 6.2 CONDITIONS FOR VARIANCES. A. Variances may be issued for the reconstruction, rehabilitation, or restoration of structures listed in the National Register of Historic Places or the State Inventory of Historic Places, without regard to the procedures set forth in the remainder of this section. B. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result. C. Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief. D. 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 to the applicant. 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, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances. E. Variances may be issued for new construction and substantial. improvements and for other development necessary for the conduct of a functionally dependent use provided that the provisions of Sections 6.2.A through 6.2.D 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. Page 13 F. Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with a lowest~ floor elevation below the regulatory flood elevation and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor, elevation. A copy of the notice shall be recorded by the Floodplain Board in the office of the Recorder of the County of Alameda and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land. SECTION 7.0 SUPERCESSION 7.1 SUPERSEDE ALAMEDA COUNTY CODE. This ordinance shall supersede the provisions of Chapter 8 of Title 7 of the Alameda County Code, as adopted by Dublin Ordinance No. 82-13. SECTION 8.0 POSTING OF ORDINANCE The City Clerk of the City of Dublin shall cause this Ordinance to be posted at least three (3) public places in the City of Dublin in accordance with Section 36933 of the Government Code of the State of California. PASSED AND ADOPTED by the City Council of the City of Dublin on this 14th day of September, 1987, . AYES: Councilmembers Hegarty, ~bffatt, Snyder, Vonheeder and Mayor Jeffery NOES: None ABSENT: None City Clerk Page 14