4800 West 92nd Avenue Westminster, CO 80031

City Government

 

8. Floodplain Regulations

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CHAPTER 8

FLOODPLAIN REGULATIONS

11-8-1:  AUTHORIZATION AND APPLICABILITY
11-8-2:  DEFINITIONS
11-8-3:  FINDINGS OF FACT
11-8-4:  STATEMENT OF PURPOSE
11-8-5:  METHODS OF REDUCING FLOOD LOSSES
11-8-6:  OFFICIAL FLOOD INSURANCE STUDY
11-8-7:  BASIS FOR ESTABLISHING THE SPECIAL FLOOD HAZARD AREA
11-8-8:  BASIS FOR DETERMINING BOUNDARIES OF THE 100-YEAR FLOODPLAIN AND FLOODWAY
11-8-9:  COMPLIANCE
11-8-10:  ABROGATION AND GREATER RESTRICTIONS
11-8-11:  INTERPRETATION
11-8-12:  WARNING AND DISCLAIMER OF LIABILITY
11-8-13:  FLOODPLAIN REGULATIONS AND FLOODPLAIN DEVELOPMENT PERMITS
11-8-14:  FLOODWAY REGULATIONS
11-8-15:  STANDARDS FOR WATERCOURSE ALTERATION
11-8-16:  NON-CONFORMING STRUCTURES
11-8-17:  FLOODPLAIN ORDINANCE ADMINISTRATOR
11-8-18:  VARIANCES
11-8-19:  RECORDS
11-8-20:  STANDARDS FOR CRITICAL FACILITIES

11-8-1:  AUTHORIZATION AND APPLICABILITY:  (2534 3714)  Pursuant to Article XX of the Constitution of the State of Colorado and section 31-23-301, C. R. S., the City of Westminster has the authority to adopt flood control regulations designed to promote the public health, safety and general welfare of its citizenry.  These regulations shall apply to all special flood hazard areas and areas removed from the floodplain by the issuance of a FEMA letter of map revision based on fill (LOMR-F) within the City.

11-8-2:  DEFINITIONS:  (2534 3714) The following words, terms and phrases, when used in this Chapter, shall have the following meanings, unless the context clearly indicates otherwise: 

“100-Year Flood” shall mean a flood having a recurrence interval that has a one-percent chance of being equaled or exceeded during any given year (1-percent-annual-chance flood).  The terms "one-hundred-year flood" and "one percent chance flood" are synonymous with the term "100-year flood."  The term does not imply that the flood will necessarily happen once every one hundred years.

“100-Year Floodplain” shall mean the area of land susceptible to being inundated as a result of the occurrence of a one-hundred-year flood.

“500-Year Flood” shall mean a flood having a recurrence interval that has a 0.2-percent chance of being equaled or exceeded during any given year (0.2-percent-chance-annual-flood).  The term does not imply that the flood will necessarily happen once every five hundred years.

“500-Year Floodplain” shall mean the area of land susceptible to being inundated as a result of the occurrence of a five-hundred-year flood.

“Addition” shall mean any activity that expands the enclosed footprint or increases the square footage of an existing structure.

“Area of Shallow Flooding” shall mean a designated Zone AO or AH on a community's Flood Insurance Rate Map (FIRM) with a one-percent chance or greater annual chance of flooding to an average depth of one to three feet where a clearly defined channel does not exist, where the path of flooding is unpredictable and where velocity flow may be evident.  Such flooding is characterized by ponding or sheet flow.

“Base Flood Elevation (BFE)” shall mean the elevation shown on a FEMA Flood Insurance Rate Map for Zones AE, AH, A1-A30, AR, AR/A, AR/AE, AR/A1-A30, AR/AH, AR/AO, V1-V30, and VE that indicates the water surface elevation resulting from a flood that has a one percent chance of equaling or exceeding that level in any given year.

“Basement” shall mean any area of a building having its floor sub-grade (below ground level) on all sides.“Channel” shall mean the physical confine of stream or waterway consisting of a bed and stream banks, existing in a variety of geometries.

“Channelization” shall mean the artificial creation, enlargement or realignment of a stream channel. 

“Code of Federal Regulations (CFR)” shall mean the codification of the general and permanent Rules published in the Federal Register by the executive departments and agencies of the Federal Government. It is divided into 50 titles that represent broad areas subject to Federal regulation.

“Community” shall mean any political subdivision in the state of Colorado that has authority to adopt and enforce floodplain management regulations through zoning, including, but not limited to, cities, towns, unincorporated areas in the counties, Indian tribes and drainage and flood control districts.

“Conditional Letter of Map Revision (CLOMR)” shall mean FEMA's comment on a proposed project, which does not revise an effective floodplain map, which would, upon construction, affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodplain.

“Critical Facility” shall mean a structure or related infrastructure, but not the land on which it is situated, that if flooded may result in significant hazards to public health and safety or interrupt essential services and operations for the community at any time before, during and after a flood.  The classification and detailed description of critical facilities is specified in Rule 6 of the Department of Natural Resources, Colorado Water Conservation Board’s “Rules and Regulations for Regulatory Floodplains in Colorado,” dated November 17, 2010, or as such rule is amended.

“DFIRM Database” shall mean the database (usually spreadsheets containing data and analyses) that accompany the DFIRM.  The “FEMA Mapping Specifications and Guidelines” outline requirements for the development and maintenance of DFIRM databases.

“Digital Flood Insurance Rate Map (DFIRM)” shall mean the FEMA digital floodplain map.  These digital maps serve as “regulatory floodplain maps” for insurance and floodplain management purposes.

“Elevated Building” shall mean a non-basement building (i) built, in the case of a building in Zones A1-30, AE, A, A99, AO, AH, B, C, X, and D, to have the top of the elevated floor above the highest adjacent grade level by means of pilings, columns (posts and piers), or shear walls parallel to the flow of the water and (ii) adequately anchored so as not to impair the structural integrity of the building during a flood of up to the magnitude of the base flood.  In the case of Zones A1-30, AE, A, A99, AO, AH, B, C, X, and D, "elevated building" also includes a building elevated by means of fill or solid foundation perimeter walls with openings sufficient to facilitate the unimpeded movement of flood waters.

“Existing Manufactured Home Park or Subdivision” shall mean a manufactured or mobile 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 January 27, 2014.

“Expansion to an Existing Manufactured Home Park or Subdivision” shall mean the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured or mobile 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).

“Federal Register” shall mean the official daily publication for Rules, proposed Rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents.

“FEMA” shall mean the Federal Emergency Management Agency, the agency responsible for administering the National Flood Insurance Program.

“Flood Insurance Rate Map (FIRM)” shall mean an official map of a community, on which the Federal Emergency Management Agency has delineated both the Special Flood Hazard Areas and the risk premium zones applicable to the community.

“Flood Insurance Study (FIS)” shall mean the official report provided by the Federal Emergency Management Agency.  The report contains the Flood Insurance Rate Map as well as flood profiles for studied flooding sources that can be used to determine Base Flood Elevations for some areas.

“Floodplain or Flood-Prone Area” shall mean any land area susceptible to being inundated as the result of a flood, including the area of land over which floodwater would flow from the spillway of a reservoir.

“Floodplain Ordinance Administrator” or “Floodplain Administrator” shall mean the City’s official designated to administer and enforce the floodplain management regulations.

“Floodplain Development Permit” shall mean the permit required before construction or development begins within any Special Flood Hazard Area (SFHA).  For those areas where FEMA has not defined a SFHA, the City shall require permits for all proposed construction or other development including the placement of manufactured homes, so that it may determine whether such construction or other development is proposed within flood-prone areas.  Permits are required to ensure that proposed development projects meet the requirements of the NFIP and this floodplain management ordinance.

“Floodplain Management Regulations” shall mean the City’s zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as a floodplain ordinance, stormwater quality ordinance) and other applications of police power.  The term also describes such state or local regulations, in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.

“Floodproofing” shall mean any combination of structural and/or non-structural 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 Control Structure” shall mean a physical structure designed and built expressly or partially for the purpose of reducing, redirecting, or guiding flood flows along a particular waterway.  These specialized flood modifying works are those constructed in conformance with sound engineering standards.

“Floodway or “Regulatory Floodway” shall mean the channel of a river or other watercourse and 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.  The Colorado statewide standard for the designated height to be used for all newly studied reaches shall be one-half (0.5) foot (six inches).  Letters of Map Revision to existing floodway delineations may continue to use the floodway criteria in place at the time of the existing floodway delineation.

“Freeboard” shall mean the vertical distance in feet above a predicted water surface elevation intended to provide a margin of safety to compensate for unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood such as debris blockage of bridge openings and the increased runoff due to urbanization of the watershed.

“Highest Adjacent Grade” shall mean the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

“Historic Structure” shall mean 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:
                (a)   By an approved state program as determined by the Secretary of the Interior, or
                (b)   Directly by the Secretary of the Interior in states without approved programs.

“Letter of Map Revision (LOMR)” shall mean FEMA's official revision of an effective Flood Insurance Rate Map (FIRM), or Flood Boundary and Floodway Map (FBFM), or both.  LOMRs are generally based on the implementation of physical measures that affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway, the effective Base Flood Elevations (BFEs), or the Special Flood Hazard Area (SFHA).

“Letter of Map Revision Based on Fill (LOMR-F)” shall mean FEMA’s modification of the Special Flood Hazard Area (SFHA) shown on the Flood Insurance Rate Map (FIRM) based on the placement of fill outside the existing regulatory floodway but inside the flood storage area.

“Levee” shall mean a man-made embankment, usually earthen, 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.  For a levee structure to be reflected on the FEMA FIRMs as providing flood protection, the levee structure must meet the requirements set forth in 44 CFR 65.10.

“Levee System” shall mean 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 Adjacent Grade (LAG)” shall mean the lowest elevation of the ground surface touching a structure.

“Lowest Floor” shall mean the lowest floor of the lowest enclosed area (including basement).  Any floor used for living purposes which includes working, storage, sleeping, cooking and eating, or recreation or any combination thereof.  This includes any floor that could be converted to such a use such as a basement or crawl space.  The lowest floor is a determinate for the flood insurance premium for a building, home or business.  An unfinished or flood resistant enclosure, usable solely for parking or 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 requirement of Section 60.3 of the National Flood Insurance Program regulations.

“Mean Sea Level” shall mean the North American Vertical Datum (NAVD) of 1988 or other datum, to which Base Flood Elevations shown on the City's Flood Insurance Rate Map are referenced.

“National Flood Insurance Program (NFIP)” shall mean FEMA’s program of flood insurance coverage and floodplain management administered in conjunction with the Robert T. Stafford Relief and Emergency Assistance Act.  The NFIP has applicable Federal regulations promulgated in Title 44 of the Code of Federal Regulations.  The U.S. Congress established the NFIP in 1968 with the passage of the National Flood Insurance Act of 1968.

“New Manufactured Home Park or Subdivision” shall mean a manufactured or a mobile 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 January 27, 2014.

“No-Rise Certification” shall mean a record of the results of an engineering analysis conducted to determine whether a project will increase flood heights in a floodway.  A No-Rise Certification must be supported by technical data and signed by a registered Colorado Professional Engineer.  The supporting technical data should be based on the standard step-backwater computer model used to develop the 100-year floodway shown on the Flood Insurance Rate Map (FIRM) or Flood Boundary and Floodway Map (FBFM).

“Physical Map Revision (PMR)” shall mean FEMA’s action whereby one or more map panels are physically revised and republished.  A PMR is used to change flood risk zones, floodplain and/or floodway delineations, flood elevations, and/or planimetric features.

“Special Flood Hazard Area” or “Flood Hazard Area” shall mean the land in the floodplain within a City subject to a one percent or greater chance of flooding in any given year, i.e., the 100-year floodplain.

“Structure” shall mean a walled and roofed building, including a gas or liquid storage tank, which is principally above ground, as well as a manufactured home.

“Substantial Damage” shall mean 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 just prior to when the damage occurred.

“Substantial Improvement” shall mean any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds fifty percent (50%) of the market value of the structure before start of construction of the improvement.  This 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 of state or local health, sanitary, or safety code specifications that have been identified by the local code enforcement official and that are the minimum necessary to insure 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” shall mean a grant of relief to a person from the requirement of this ordinance when specific enforcement would result in unnecessary hardship.  A variance, therefore, permits construction or development in a manner otherwise prohibited by this ordinance.  (For full requirements see Section 60.6 of the National Flood Insurance Program regulations).

“Violation” shall mean the failure of a structure or other development to be fully compliant with the community's floodplain management regulations.  A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in Section 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed to be in violation until such time as that documentation is provided.

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

11-8-3:  FINDINGS OF FACT:  (2534 3714)

(A)    The special flood hazard areas of the City are subject to periodic inundation, which may result 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 would adversely affect the public health, safety and general welfare.

(B)    These flood losses are caused by the cumulative effect of obstructions in floodplains that increase flood heights and velocities and, by the occupancy of special flood hazard areas by uses or structures vulnerable to floods and hazardous to other lands because they are inadequately floodproofed or elevated or otherwise protected from flood damage.

11-8-4:  STATEMENT OF PURPOSE:  (2534 3714)  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 to 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 flood hazard areas;

(F)     To help maintain a stable tax base, by providing for the sound use and development of flood hazard areas so as to minimize future flood blight areas;

(G)    To ensure that potential buyers are notified that property is in a flood hazard area;

(H)    To ensure that those who occupy the flood hazards areas assume responsibility for their actions; and

(I)     Encourage and facilitate urban water resources management techniques for the reduction of pollution and the enhancement of the urban environment.

11-8-5:  METHODS OF REDUCING FLOOD LOSSES:  (2534 3714)  In order to accomplish its purposes, this ordinance includes methods and provisions for:

(A)    Restricting or prohibiting uses that are dangerous to health, safety and property in times of flooding or that cause excessive increases in flood heights or velocities.

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

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

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

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

11-8-6:  OFFICIAL FLOOD INSURANCE STUDY:  (3714)  The Flood Insurance Study for Jefferson County, Colorado, as provided to the City by the Federal Emergency Management Agency, along with its accompanying FIRMs (effective February 5, 2014) and any revisions thereto are adopted as the applicable FIS and FIRMs for the City.  The Floodplain Administrator shall keep a copy of the Flood Insurance Study (FIS), DFIRMs and FIRMs on file and available for public inspection.

11-8-7:  BASIS FOR ESTABLISHING THE SPECIAL FLOOD HAZARD AREA:  (2534 3714)  The Special Flood Hazard Areas (SFHA) within the City are those identified in the official FIS.  These Special Flood Hazard Areas identified by the FIS and attendant mapping are the minimum areas of the City subject to the applicability of this ordinance and may be supplemented by studies designated and approved by the City of Westminster.

11-8-8:  BASIS FOR DETERMINING BOUNDARIES OF THE 100-YEAR FLOODPLAIN AND FLOODWAY:  (2534 3714)  

(A)    The boundaries of the one-hundred- (100-) year floodplain and the floodway shall be determined from information presented in the Flood Insurance Study (FIS).  In the absence of other information (i.e., site specific studies as provided by the property owner), boundaries shall be determined by scaling distances on the maps provided in the FIS.  Where interpretation is needed as to the exact location of the boundaries, the floodplain administrator shall make the necessary interpretation.  In all cases, the one-hundred- (100-) year flood elevation as provided in the FIS shall be the governing factor in locating the boundary on any property.

(B)    If the FIS does not provide one-hundred- (100-) year flood elevations, then the floodplain administrator shall obtain, review and reasonably utilize any one-hundred- (100-) year flood elevation and floodway data available from any federal, state, local or other source as criteria for requiring that new construction, substantial improvements or other developments in floodplain areas are administered in accordance with this Chapter.

11-8-9:  COMPLIANCE:  (2534 3714)  No structure shall hereafter be constructed, located, extended, converted or altered without full compliance with the terms of this ordinance and other applicable regulations.  Nothing herein shall prevent the City from taking such lawful action as is necessary to prevent or remedy any violation of this Chapter.  These regulations meet the minimum requirements as set forth by the Colorado Water Conservation Board and the National Flood Insurance Program.

11-8-10:  ABROGATION AND GREATER RESTRICTIONS:  (2534)  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.

11-8-11:  INTERPRETATION:  (2534)  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; and

(C)    Deemed neither to limit nor repeal any other powers granted under State statutes.

11-8-12:  WARNING AND DISCLAIMER OF LIABILITY:  (2534)  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 the one-hundred- (100-) year floodplains 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 Westminster, any officer or employee thereof, or Federal Emergency Management Agency for any flood damages that result from reliance on this ordinance or any administrative decision lawfully made thereunder.

11-8-13:  FLOODPLAIN REGULATIONS AND FLOODPLAIN DEVELOPMENT PERMITS:  (2534 3714)  The following regulations shall apply to all lands located within the one-hundred- (100-) year floodplain:

(A)    General Standards:

        (1)  All proposed developments within the Special Flood Hazard Area shall be designed and constructed in accordance with this ordinance and shall not adversely affect any upstream, downstream or adjacent properties.

        (2)  No development, use, fill, construction or alteration on or over any portion of a designated floodplain shall be permitted that would cause or result in any of the following:
              (a)     The storage or processing of materials that in times of flooding are buoyant, flammable, explosive or otherwise potentially injurious to human, animal or plant life.
              (b)     The disposal of garbage or other solid waste materials.
              (c)     Substantial solid debris being carried downstream by flood waters.
              (d)     Any obstruction that would impair the flow capacity of a designated floodplain so as to cause foreseeable damage to others, wherever located.

        (3)  All new construction, lateral additions and substantial improvements (including the placement of prefabricated buildings and manufactured homes) shall be:
              (a)     Designed or modified and adequately anchored to prevent flotation, collapse or lateral movement of the structure;
              (b)     Designed and constructed with materials and utility equipment resistant to flood damage;
              (c)     Designed and constructed by methods and practices that minimize flood damage; 
              (d)     Designed and 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; and
              (e)     Designed and constructed in conformance with all sections of this Chapter.

(B)  Residential Structures: 

        (1)   In floodplain areas in which the one-hundred- (100-) year flood elevations are not known, all new construction and substantial improvements of residential structures shall have the lowest floor, including basement, elevated two feet (2') above the gutter flowline of the nearest street.

        (2)   In floodplain areas in which the base flood elevation (BFE) is known, all new construction and substantial improvements of residential construction shall have the lowest floor, including basement, elevated one foot (1') above the BFE as indicated in the Flood Insurance Study (FIS).

        (3)   Require within any AO Zone that all new construction and substantial improvements of residential structures have the lowest floor (including basement) elevated three feet (3’) above the highest adjacent grade, if no depth number is specified, or at least one foot higher than the depth number specified (in feet) in the FIS.

        (4)   Within Zones AH or Zone AO, adequate drainage paths around structures on slopes are required to guide floodwaters around and away from proposed structures.

        (5)   No new residential lot shall be platted if located entirely within the 100-year floodplain.  Any use of or construction upon a residential lot that is partially located in the 100-year floodplain must comply with all requirements of this Chapter.

(C)    Non-Residential Structures:

        (1)   In floodplain areas in which the 100-year flood elevations are not known, all new construction and substantial improvements of non-residential structures shall have the lowest floor, including basement, elevated two feet (2') above the gutter flow line of the nearest street.

        (2)   In floodplain areas in which the BFE is known, all new construction and substantial improvements of non-residential construction shall have the lowest floor, including basement, elevated one foot (1') above the BFE as indicated in the FIS.

        (3)   Require within any AO Zone that all new construction and substantial improvements of non-residential structures have the lowest floor (including basement) elevated three feet (3’) above the highest adjacent grade, if no depth number is specified, or at least one foot higher than the depth number specified (in feet) on the FIS or, together with attendant utility and sanitary facilities, be completely floodproofed to that level to meet the floodproofing standards specified in (5) below.

        (4)    Within Zones AH or Zone AO, adequate drainage paths around structures on slopes are required to guide floodwaters around and away from proposed structures.

        (5)    As an alternative for non-residential structures only, the structure, including utility and sanitary facilities, can be completely floodproofed to the levels mentioned above.  The walls and basement floor shall be completely waterproofed and they shall be built to withstand lateral and uplift water pressure, and
                (a)  Be floodproofed so that, below the BFE, 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 that the design and methods of construction are in accordance with accepted standards of 
                      practice for meeting the provisions of this paragraph.  Such certification shall be provided to the floodplain administrator.

        (6)   When floodproofing is used for nonresidential structures, a registered professional engineer shall certify that the flood proofing methods are adequate to withstand the flood pressures, velocities, impact and uplift forces, and other factors caused by the one-hundred- (100-) year flood.  A record of this certification shall be maintained on file with the building permit by the Building Official.  The elevation to which the structure is flood proofed (based on mean sea level) shall be noted on the certification.

(D)    Manufactured Homes: 

        (1)   All new individual manufactured homes or other new manufactured structures, new manufactured home parks, expansions of manufactured home parks and manufactured home parks where the repair, reconstruction or improvements of the streets, utilities and pads equal or exceed fifty percent (50%) of their value before the repair, reconstruction or improvements was started, shall have stands or lots that are elevated on compacted fill or on pilings so that the lowest floor of the manufactured home will be two feet (2') above the one-hundred- (100-) year flood elevation, as indicated in the appropriate Official Flood Study, and adequate surface drainage and access for a hauler are provided.  When manufactured homes are put on pilings, the pilings shall be designed and certified by a registered professional engineer and shall be installed in conformance with that design.

        (2)   All new manufactured homes and substantially improved manufactured homes located in the one-hundred- (100-) year floodplain shall be anchored to resist flotation, collapse or lateral movement of the structure and capable of resisting the hydrostatic and hydrodynamic loads.  The anchoring shall be designed and certified by a registered professional engineer.  Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors.  This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.  Specific requirements may be:
               (a) Over-the-top ties provided at each of the four (4) corners with one (1) mid-point tie on each side of the manufactured home shorter than fifty feet (50').  Manufactured homes longer than fifty feet (50') shall have two (2) ties at intermediate points on each side. 
               (b) Frame ties provided at each corner with four (4) additional ties on each side of manufactured homes shorter than fifty feet (50').  Longer manufactured homes shall have five (5) ties on each side.
               (c)  ll components of the anchoring system shall have a minimum strength of forty-eight hundred (4,800) pounds.  
               (d)  Any additions to manufactured homes shall be anchored in the same way. 

(E)    Recreational Vehicles:  It is a requirement that all recreational vehicles:

        (1)   Be on the site for fewer than one hundred eighty (180) consecutive days;

        (2)   Be fully licensed and ready for highway use; and

        (3)   Meet the permit requirements and elevation and anchoring requirements for resisting wind forces.

(F)     New Development Proposals:  All new development proposals, including subdivision proposals, shall be designed to minimize flooding potential.  If all or part of a proposed development is located within a one-hundred- (100-) year floodplain, then the corresponding proposal shall conform to the following guidelines:

        (1)    All subdivision proposals shall be consistent with the need to minimize flood damage;

        (2)    All subdivision proposals shall have public utilities and facilities, such as sewer, gas, electrical and water systems, located and constructed to minimize flood damage;

        (3)    All subdivision proposals shall have adequate drainage facilities provided to reduce exposure to flood damage; and

        (4)    Base flood elevation data shall be provided for all subdivision proposals and any other proposed developments.

(G)    Construction Materials and Methods: 

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

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

        (3)    All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

(H)    Utilities: 

        (1)    All new replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system;

        (2)    New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters; and

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

(I)     Establishment of Floodplain Development Permit:  A Floodplain Development Permit shall be obtained before construction or development begins within any one-hundred- (100-) year floodplain area as established in the FIS.  Application for a Floodplain Development Permit shall be made on forms furnished by the City of Westminster and may include, but are not limited to:   Plans in duplicate drawn to scale showing the nature, location, dimensions and elevations 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)    Elevation in relation to mean sea level of the lowest floor, including basement, of all structures;

        (2)    Elevation in relation to mean sea level to which any structure has been flood proofed;

        (3)    Certification by a registered professional engineer that the flood proofing methods for any nonresidential structure meet the flood proofing criteria in Section 11-8-13(C), W.M.C., above; and

        (4)    Description and analysis prepared by a registered professional engineer of the extent to which any watercourse, floodplain or floodway will be altered or relocated as a result of proposed development.

(J)     Review of Floodplain Development Permits:  The City of Westminster will:

        (1)     Review all Floodplain Development Permit applications to determine that the permit requirements of this ordinance have been satisfied.

        (2)     Review all Floodplain Development Permit applications to determine that all necessary permits (e.g., 404 permit, storm sewer outfall permit, FEMA permits, etc.) have been obtained by the applicant from federal, State or local governmental agencies from which approval is required prior to the City of Westminster's approval of the Floodplain Development Permit.

        (3)      Review all Floodplain Development Permit applications to determine if the proposed development is located in the floodway.  If located in the floodway, assure that the provisions as set forth in Section 11-8-14, W.M.C., have been met.

        (4)      Review all building permit applications to determine whether proposed building sites will be reasonably safe from flooding.

        (5)      Require every applicant to submit certification from a registered land surveyor identifying the elevation of the lowest floor, including basement.

(K)    FLOODPLAIN DEVELOPMENT PERMIT FOR PROPERTY REMOVED FROM THE FLOODPLAIN BY FILL:  The City will not issue a floodplain development permit for the construction of a new structure or an addition to an existing structure on a property that has been removed from the floodplain by the issuance of a FEMA LOMR-F, unless the elevation of the lowest floor is placed one (1’) foot above the BFE that existed prior to the placement of the approved fill.

11-8-14:  FLOODWAY REGULATIONS:  (2534 3714)  

(A)    The State of Colorado has adopted standards for the floodway that are more stringent than the FEMA minimum standards. Because floodways are extremely hazardous areas due to the velocity of floodwaters, which carry debris, potential projectiles and significant amounts of eroded materials, only the following uses are permitted in the regulatory floodway:

        (1)   General farming, pasture, outdoor plant nurseries, horticulture, forestry, wildlife sanctuary, game farm and other similar agricultural, wildlife and related uses.

        (2)    Lawns, gardens, play areas, bikeways, pedestrian pathways and other similar uses.

        (3)    Portions of golf courses, driving ranges, archery ranges, fair grounds, parks, hiking or horseback riding trails, open space and other similar private and public recreational uses not involving structures.

        (4)    Buried or underground utility lines.

(B)    The uses permitted in subsection (A) above may not involve any encroachment such as fill, new construction, substantial improvements or any other development within or above the floodway, unless certification is provided by a registered professional engineer demonstrating that such encroachment shall not result in any increase in the BFE or have any negative impacts on upstream, downstream or adjacent properties.

(C)    Notwithstanding the above provisions, under the provisions of 44 CFR Chapter 1, Section 65.12, of the National Flood Insurance Regulations, the City may permit encroachments within the adopted regulatory floodway that would result in an increase in BFE, provided that the City first applies for a CLOMR and receives a floodway revision through FEMA.

11-8-15:  STANDARDS FOR WATERCOURSE ALTERATION:  (3714)  For all proposed developments that alter a watercourse within a Special Flood Hazard Area, the following standards apply:

(A)  Applicants proposing channelization and flow diversion projects shall appropriately consider issues of sediment transport, erosion, deposition, and channel migration and properly mitigate potential problems through the project as well as upstream and downstream of any improvement activity.  A detailed analysis of sediment transport and overall channel stability may be required by the City to assist in determining the most appropriate design.

(B)  Channelization and flow diversion projects shall identify and evaluate the residual 100-year floodplain.

(C)  Any channelization or other stream alteration activity proposed by a project proponent must be evaluated for its impact on the regulatory floodplain and be in compliance with all applicable Federal, State and local floodplain rules, regulations and ordinances.

(D)  Any stream alteration activity shall be designed and stamped by a registered Colorado Professional Engineer or Certified Professional Hydrologist.

(E)  All activities within the regulatory floodplain shall meet all applicable federal, state and local floodplain requirements and regulations.

(F)  Within the regulatory floodway, stream alteration activities shall not be constructed unless the project proponent demonstrates through a floodway analysis and report, stamped by a registered Colorado Professional Engineer, that there is no rise in the existing BFE resulting from the project (otherwise known as a No-Rise Certification), unless the City first applies for and receives a CLOMR and Floodway revision.

(G)  Applicants must demonstrate that future maintenance of the channelization or flow diversion project will occur for any altered or relocated portions of watercourses so that the flood-carrying capacity is not diminished.

11-8-16:  NON-CONFORMING STRUCTURES:  (2534 3417)  A structure that was lawful before becoming subject to this Chapter, but which is not in conformity with the provisions of this Chapter, may be continued, subject to the following conditions:

(A)  Such structure shall not be expanded, changed, enlarged or altered in a way that increases its nonconformity.

(B)  If any nonconforming structure is destroyed by any means, including floods, to the extent that the cost of restoration would equal or exceed fifty percent (50%) of the market value of the structure before the structure was damaged, the following regulations shall apply:

       (1) If the nonconforming structure is in the floodway, the structure may be rebuilt; however, it shall not be expanded, changed, enlarged or altered in any way that would create an obstruction to water flow greater than that which existed before damage to the structure occurred.  Upon reconstruction, nonresidential and residential structures shall be elevated two feet (2') above the one-hundred- (100-) year flood elevation, as indicated in the appropriate Flood Insurance Study.  As an alternative nonresidential facilities can be completely flood proofed two feet (2') above the one-hundred- (100-) year flood elevation, as indicated in the appropriate Flood Insurance Study.  The walls and basement floor shall be completely flood proofed and they shall be built to withstand lateral and uplift water pressure.

       (2) If the structure is located in the flood storage area, it may be reconstructed, provided nonresidential and residential structures are elevated two feet (2') above the one-hundred- (100-) year flood elevation, as indicated in the appropriate Flood Insurance Study. 

       (3) As an alternative for nonresidential structures only, the structure, including utility and sanitary facilities, can be completely flood proofed two feet (2') above the one-hundred- (100-) year flood elevation, as indicated in the appropriate Flood Insurance Study.  The walls and basement floor shall be completely flood proofed and they shall be built to withstand lateral and uplift water pressure.

       (4) If any manufactured home or home park is destroyed by any means such that the cost of restoration would exceed fifty percent (50%) of the market value of the structure prior to damage, then such manufactured home or manufactured home park shall not be rebuilt if it is located in the floodway and, if it is located in the flood storage area, it shall be rebuilt in conformance with this ordinance.

11-8-17:  FLOODPLAIN ORDINANCE ADMINISTRATOR:  (2534 3714)  This ordinance shall be administered and enforced by the Director of Community Development or his designee.

11-8-18:  VARIANCES:  (2534 3714)

(A)    Appeal Board:

        (1)  The Director of Community Development shall hear and decide requests for variances from the requirements of this ordinance. 

        (2)   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 Director of Community Development in the enforcement or administration of this ordinance.

        (3)   Those aggrieved by the decision of the City Council, or any taxpayer, may appeal such decisions to a court of competent jurisdiction.

        (4)    In passing upon such applications, the Director of Community Development and the City Council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this ordinance, and:
                (a) The danger that materials may be swept onto other lands to the injury of others;
                (b) The danger to life and property due to flooding or erosion damage;
                (c)  The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owners;
                (d)  The importance of the services provided by the proposed facility to the community;
                (e)  The necessity to the facility of a waterfront location, where applicable;
                (f)   The availability of alternative locations for the proposed use that are not subject to flooding or erosion damage;
                (g)  The compatibility of the proposed use with the existing and anticipated development;
                (h)  The relationship of the proposed use to the Comprehensive Plan and floodplain management program for that area;
                (i)   The safety of access to the property in times of flood for ordinary and emergency vehicles;
                (j)   The expected heights, velocity, duration, rate of rise and sediment transport of the flood waters and the effects of wave action, if applicable, expected at the site; and
                (k)   The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities, such as sewer, gas, electrical and water systems, streets and bridges.

        (5)    Upon consideration of the factors of Section 11-8-18(A)(4), W.M.C., and the purposes of this ordinance, the Director of Community Development or the City Council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this ordinance.

        (6)    The City of Westminster shall maintain the records of all appeal actions, including technical information, and report any variances to the Federal Emergency Management Agency.

(B)    Conditions for Variances:

        (1)    Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half (1/2) acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base level, providing items (a)-(k) in Section 11-8-18(A)(4), W.M.C., have been fully considered.  As the lot size increases beyond the one-half (1/2) acre, the technical justifications required for issuing the variance increases.

        (2)    Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as an historic structure and the variance is the minimum necessary to preserve the historic character and design of the structure.

        (3)    Variances shall not be issued within any designated floodway, if any increase in the one-hundred- (100-) year flood elevation 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.

        (5)    Variances shall only be issued upon:
                (a)  A showing of good and sufficient cause;
                (b)  A determination that failure to grant the variance would result in exceptional hardship to the applicant; and
                (c)  A determination that the granting of a variance will not result in increased flood heights, increased velocities, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public, as identified in Section 11-8-18(A)(4), W.M.C., or conflict with existing local laws or ordinances.

         (6)  Any applicant to whom a variance is granted shall be given written notice that the cost of flood insurance will be commensurate with the increased risk from the granting of the variance.

11-8-19:  RECORDS:  (2534)  The City of Westminster shall obtain, maintain, and have available for public inspection:

(A)   All of the Flood Insurance Studies.

(B)   Certificates of flood proofing and a statement whether a structure has been flood proofed and to what elevation (with building permits, as applicable).

(C)   For structures in the floodplain:

        (1)  Information on the elevation of the lowest floor, including basement, for all new or substantially improved structures; and

        (2)  A statement whether a new or substantially improved structure contains a basement.

11-8-20:  STANDARDS FOR CRITICAL FACILITIES:  (3714)  The City will use the following criteria in order to identify and confirm which specific structures within the City are critical facilities:

(A)    CLASSIFICATION OF CRITICAL FACITILIES:  Critical Facilities are classified under the following categories:  (1) Essential Services; (2) Hazardous Materials; (3) At-risk Populations; and (4) Vital to Restoring Normal Services.

        (1)    Essential Services facilities include public safety, emergency response, emergency medical, designated emergency shelters, communications, public utility plant facilities, and transportation lifelines.
                (a)    These facilities consist of: 
                        (i)      Public safety (police stations, fire and rescue stations, emergency vehicle and equipment storage, and, emergency operation centers);
                        (ii)     Emergency medical (hospitals, ambulance service centers, urgent care centers having emergency treatment functions, and non-ambulatory surgical structures, but not including clinics, doctor’s offices, and non-urgent care medical structures that do not provide these functions); 
                        (iii)    Designated emergency shelters; 
                        (iv)    Communications (main hubs for telephone, broadcasting equipment for cable systems, satellite dish systems, cellular systems, television, radio, and other emergency warning systems, but excluding towers, poles, lines, cables, and conduits); 
                        (v)     Public utility plant facilities for generation and distribution ( hubs, treatment plants, substations and pumping stations for water, power and gas, but not including towers, poles, power lines, buried pipelines, transmission lines, distribution lines, and service lines); and 
                        (vi)    Air transportation lifelines (municipal and larger airports, helicopter pads and structures serving emergency functions, and associated infrastructure such as aviation control towers, air traffic control centers, and emergency equipment aircraft hangars). 
                (b)  Specific exemptions to this category include wastewater treatment plants (WWTP), non-potable water treatment and distribution systems, and hydroelectric power generating plants and related appurtenances, which have plans in place to avoid system failures during extreme floods events and adequate restoration plans following flood emergencies. 
                (c)   Public utility plant facilities may be exempted if it can be demonstrated to the satisfaction of the City that the facility is an element of a redundant system for which service will not be interrupted during a flood.  At a minimum, it shall be demonstrated that redundant facilities are available (either owned by the same utility or available through an intergovernmental agreement or other contract) and connected, the alternative facilities are either located outside of the 100-year floodplain or are compliant with the provisions of this Chapter, and an operations plan is in effect that states how redundant systems will provide service to the affected area in the event of a flood.  Evidence of ongoing redundancy shall be provided to the City on an as-needed basis upon request.

        (2)    Hazardous Materials facilities include facilities that produce or store highly volatile, flammable, explosive, toxic and/or water-reactive materials.
                (a)  These facilities may include: 
                        (i)   Chemical and pharmaceutical plants (chemical plant, pharmaceutical manufacturing); 
                        (ii)   Laboratories containing highly volatile, flammable, explosive, toxic and/or water-reactive materials; 
                        (iii)  Refineries;
                        (iv)  Hazardous waste storage and disposal sites; and 
                        (v)   Above ground gasoline or propane storage or sales centers.
                (b)     Facilities shall be determined to be Critical Facilities if they produce or store materials in excess of threshold limits.  If the owner of a facility is required by the Occupational Safety and Health Administration (OSHA) to keep a Material Safety Data Sheet (MSDS) on file for any chemicals stored or used in the work place, and the chemical(s) is stored in quantities equal to or greater than the Threshold Planning Quantity (TPQ) for that chemical, then that facility shall be considered to be a Critical Facility.  The TPQ for these chemicals is: either 500 pounds or the TPQ listed (whichever is lower) for the 356 chemicals listed under 40 C.F.R. § 302 (2010), also known as Extremely Hazardous Substances (EHS); or 10,000 pounds for any other chemical.  This threshold is consistent with the requirements for reportable chemicals established by the Colorado Department of Health and Environment. OSHA requirements for MSDS can be found in 29 C.F.R. § 1910 (2010).  The Environmental Protection Agency (EPA) regulation “Designation, Reportable Quantities, and Notification,” 40 C.F.R. § 302 (2010) and OSHA regulation “Occupational Safety and Health Standards,” 29 C.F.R. § 1910 (2010) are incorporated herein by reference and include the regulations in existence at the time of the promulgation this ordinance, but exclude later amendments to or editions of the regulations         

                (c)     Specific exemptions to this category include:
                        (i) Finished consumer products within retail centers and households containing hazardous materials intended for household use, and agricultural products intended for agricultural use. 
                        (ii) Buildings and other structures containing hazardous materials for which it can be demonstrated to the satisfaction of the local authority having jurisdiction by hazard assessment and certification by a qualified professional (as determined by the local jurisdiction having land use authority) that a release of the subject hazardous material does not pose a major threat to the public. 
                        (iii)  Pharmaceutical sales, use, storage, and distribution centers that do not manufacture pharmaceutical products.

                (d)   The exemptions, listed in paragraph (c) above, shall not apply to buildings or other structures that also function as Critical Facilities under another category outlined in this section.

        (3)     At-risk Populations facilities include medical care, congregate care, and schools.

                 (a)   These facilities consist of: 
                        (i)   Elder care (nursing homes); 
                        (ii)  Congregate care serving 12 or more individuals (day care and assisted living); 
                        (iii) Public and private schools (pre-schools, K-12 schools), before-school and after-school care serving 12 or more children);

        (4)     Facilities Vital to Restoring Normal Services including government operations. 
                  (a)  These facilities consist of: 
                        (i)   Essential government operations (public records, courts, jails, building permitting and inspection services, community administration and management, maintenance and equipment centers); 
                        (ii)  Essential structures for public colleges and universities (dormitories, offices, and classrooms only).

                 (b)  These facilities may be exempted if it is demonstrated to the City that the facility is an element of a redundant system for which service will not be interrupted during a flood.  At a minimum, it shall be demonstrated that redundant facilities are available (either owned by the same entity or available through an intergovernmental agreement or other contract), the alternative facilities are either located outside of the 100-year floodplain or are compliant with this ordinance, and an operations plan is in effect that states how redundant facilities will provide service to the affected area in the event of a flood.  Evidence of ongoing redundancy shall be provided to the City on an as-needed basis upon request.

(B)    PROTECTION FOR CRITICAL FACILITIES - All new and substantially improved Critical Facilities and new additions to Critical Facilities located within the Special Flood Hazard Area shall be regulated to a higher standard than structures not determined to be Critical Facilities.  For the purposes of this, protection shall include either (1) location outside the Special Flood Hazard Area or (2) elevation or floodproofing of the structure to at least two feet above the Base Flood Elevation.

(C)    INGRESS AND EGRESS FOR NEW CRITICAL FACILITIES - New Critical Facilities shall, when practicable as determined by the City, have continuous non-inundated access (ingress and egress for evacuation and emergency services) during a100-year flood event. 

 

 

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