Gainesville › Unified Land Development Code
Article 12 — Environment, Chapter 12-2 — FLOODPLAIN MANAGEMENT
§ 12-2-1
General Provisions
(a)Findings of Fact.
(1)The flood hazard areas of the city are subject to periodic inundation which can 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 adversely affect the public health, safety and general welfare.
(2)Flood hazard areas can serve important stormwater management, water quality, stream bank protection, stream corridor protection, wetland preservation and ecological purposes when permanently protected as undisturbed or minimally disturbed areas.
(3)Effective floodplain management and flood hazard protection activities can:
i.Protect human life and health;
ii.Minimize damage to private property;
iii.Minimize damage to public facilities and infrastructure such as water and gas mains, electric, telephone and sewer lines, streets and bridges located in floodplains; and
iv.Minimize expenditure of public money for costly flood control projects associated with flooding and generally undertaken at the expense of the general public.
(4)These flood losses are increased by the cumulative effect of obstructions in floodplains causing increases in flood heights and velocities, and by the occupancy in flood hazard areas by uses vulnerable to floods or hazardous to other lands which are inadequately elevated, flood proofed, or otherwise unprotected from flood damage.
(5)Article IX, Section II of the Constitution of the State of Georgia and O.C.G.A. § 36-1-20(a) of the Official Code of Georgia Annotated have delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the City of Gainesville, Georgia, does enact this ordinance and establishes this set of floodplain management and flood hazard reduction provisions for the purpose of regulating the use of flood hazard areas. It is determined that the regulation of flood hazard areas and the prevention of flood damage are in the public interest and will minimize threats to public health and safety, as well as to private and public property.
(b)Statement of Purpose. It is the purpose of this chapter to protect, maintain, and enhance the public health, safety, environment and general welfare and to minimize public and private losses due to flood conditions in flood hazard areas, as well as to protect the beneficial uses of floodplain areas for water quality protection, stream bank and stream corridor protection, wetlands preservation and ecological and environmental protection by provisions designed to:
(1)Restrict or prohibit uses which are dangerous to health, safety and property due to flooding or erosion hazards, or which result in damaging increases in erosion or in 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)Limit the alteration of natural floodplains, stream channels, and natural protective barriers which are involved in the accommodation of flood waters;
(4)Control filling, grading, dredging and other development which may increase erosion or flood damage;
(5)Prevent or regulate the construction of flood barriers which will unnaturally divert flood- waters or which may increase flood hazards to other lands; and
(6)Protect the stormwater management, water quality, stream bank protection, stream corridor protection, wetland preservation and ecological functions of natural floodplain areas.
(c)Objectives. The objectives of this section are 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 interruption;
(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 floodplains;
(6)Help maintain a stable tax base by providing for the sound use and development of flood prone areas in such a manner as to minimize flood blight areas; and
(7)Insure that potential home buyers are notified that property is in a flood area.
(d)Applicability. This chapter shall apply to all areas of special flood hazard within the city, i.e. floodplain and flood prone areas as defined herein at or below the base flood elevation or the future conditions flood elevation, whichever is more restrictive (including A and AE on the FIRM), and all new or substantial improvement residential units, all subdivisions, non-residential structures, manufactured home, recreational vehicles, and utilities located within these areas. In addition, all streams with a drainage area of one hundred (100) acres of more have an area of special flood hazard.
(e)Adoption by Reference. The following are adopted by reference:
(1)The current effective flood insurance study (FIS) with accompanying maps and other supporting data and any revision thereto. For those land areas acquired through annexation, the current effective FIS and data for Hall County, Georgia, with accompanying maps and other supporting data and any revision thereto are hereby adopted by reference.
(2)Other studies which may be relied upon for the establishment of the base flood elevation or delineation of the 1% (100-year) floodplain and flood prone areas include:
i.Any flood or flood-related study conducted by the United States Army Corps of Engineers, the United States Geological Survey, or any other local, state or federal agency applicable to the city; and
ii.Any base flood study authored by a registered professional engineer in the state which has been prepared by FEMA approved methodology and approved by the department of water resources.
(3)Other studies which may be relied upon for the establishment of the future conditions flood elevation or delineation of the future conditions floodplain and flood prone areas include:
i.Any flood or flood-related study conducted by the United States Corps of Engineers, the United States Geological Survey, or any other local, State or Federal agency applicable to the city; or
ii.Any future conditions flood study authored by a registered professional engineer in the state which has been prepared by FEMA approved methodology and approved by the department of water resources.
(4)The repository for public inspection of the FIS, accompanying maps and other supporting data is located at the department of water resources.
(f)Interpretation. In the interpretation and application of this section, all provisions shall be:
(1)Considered as minimum requirements;
(2)Liberally construed in favor of the City Council; and
(3)Deemed neither to limit nor repeal any other powers granted under state statutes.
(g)Warning and Disclaimer of Liability. The degree of flood protection required by this section 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 hazard 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 or the county or by any officer or employee thereof for any flood damages that result from reliance on this section or any administrative decision lawfully made hereunder.
(h)Compatibility with Other Regulations. This chapter is not intended to modify or repeal any other ordinance, rule, regulation, statute, easement, covenant, deed restriction or other provision of law. The requirements of this chapter are in addition to the requirements of any other ordinance, rule, regulation or other provision of law, and where any provision of this chapter imposes restrictions different from those imposed by any other ordinance, rule, regulation or other provision of law, whichever provision is more restrictive or impose higher protective standards for human health or the environment shall control.
(i)Severability. If the provisions of any section, subsection, paragraph, subdivision or clause of this ordinance shall be adjudged invalid by a court of competent jurisdiction, such judgment shall not affect or invalidate the remainder of any section, subsection, paragraph, subdivision or clause of this ordinance.
§ 12-2-2
Administration and Permitting
(a)The Director of Water Resources, or their designee, is hereby appointed floodplain administrator to administer and implement the provisions of this chapter. The duties of the floodplain administrator regarding any land within an area of special flood hazard shall include, but not be limited to:
(1)Review all development applications and permits to assure that the requirements of this ordinance have been satisfied and to determine whether proposed building sites will be reasonably safe from flooding;
(2)Review proposed development to assure that all necessary permits have been received from those governmental agencies from which approval is required by Federal or State law, including but not limited to Section 404 of the Federal Water Pollution Control Act, Amendments of 1972, 33 U.S.C. 1334;
(3)When base flood elevation data or floodway data have not been provided, then the floodplain administrator shall require the applicant to obtain, review and reasonably utilize any base flood elevation and floodway data available from a federal, state or other source in order to meet the provisions of this chapter;
(4)Review and record the actual elevation in relation to mean sea level (or highest adjacent grade) of the lowest floor, including basement, of all new or substantially improved structures;
(5)Review and record the actual elevation, in relation to mean sea level to which any substantially improved structures have been flood-proofed;
(6)When flood-proofing is utilized for a structure, the floodplain administrator shall obtain certification of design criteria from a registered professional engineer or architect;
(7)Notify affected adjacent communities and the state department of natural resources prior to any alteration or relocation of a watercourse and submit evidence of such notification to the Federal Emergency Management Agency (FEMA);
(8)Where interpretation is needed as to the exact location of boundaries of the areas of special flood hazard (e.g., where there appears to be a conflict between a mapped boundary and actual field conditions) the floodplain administrator shall make the necessary interpretation. Any person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in this chapter. Where floodplain elevations have been defined, the floodplain shall be determined based on flood elevations rather than the area graphically delineated on the floodplain maps;
(9)All records pertaining to the provisions of this chapter shall be maintained in the office of the floodplain administrator and shall be open for public inspection;
(10)Coordinate all FIRM revisions with the GA DNR and FEMA; and
(11)Review variance applications and make recommendations to the Department of Community and Economic Development.
(b)Permit Application Requirements.
(1)No owner or developer shall perform any development activities on a site where an area of special flood hazard or area of future-conditions flood hazard is located without first meeting the requirements of this ordinance prior to commencing the proposed activity.
(2)Unless specifically excluded by this ordinance, any landowner or developer desiring a permit for a development activity shall submit to the city a land disturbance permit application on a form provided by the city for that purpose.
(3)No permit will be approved for any development activities that do not meet the requirements, restrictions and criteria of this ordinance.
(c)Floodplain Management and Flood Damage Prevention Plan. No application for a land development project within any area of special flood hazard will be approved unless it includes a floodplain management/flood damage prevention plan (floodplain management plan). This plan shall be in accordance with the following criteria:
(1)This plan must be submitted with the stamp and signature of a professional engineer (PE) licensed in the state, who will verify that all designs are consistent with the requirements of this chapter.
(2)The approved floodplain management plan shall contain certification by the applicant that all land development activities will be done according to the plan or previously approved revisions. Any and all development permits and/or use and occupancy certificates or permits may be revoked at any time if the construction and building activities are not in strict accordance with approved plans.
(3)The floodplain management plan shall include, but not be limited to, the following:
plans drawn to scale of the site in question, existing and proposed elevations of the area in question and the nature, location, and dimensions of existing or proposed structures, proposed grading plan, earthen fill placement, amount and location of excavation, storage of materials or equipment, and drainage/stormwater management facilities.
(d)Specific Requirements for Plans. The following information is required as a part of floodplain management/flood damage prevention plans:
(1)Site plan drawn to scale, including but not limited to:
i.Existing and proposed elevations of the area in question and the nature, location and dimensions of existing and/or proposed structures, earthen fill placement, amount and location of excavation material, and storage of materials or equipment;
ii.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;
iii.Proposed locations of water supply, sanitary sewer, and utilities;
iv.The base flood elevation and future conditions flood elevation;
v.Boundaries of the base flood floodplain and future conditions floodplain;
vi.If applicable, the location of the floodway;
vii.Proposed locations of drainage and stormwater management facilities;
viii.Proposed grading plan; and
ix.Certification of the above by a registered professional engineer or surveyor.
(2)Building and foundation design detail, including but not limited to:
i.Proposed elevation in relation to mean sea level (or highest adjacent grade)
of the lowest floor, including basement, of all structures;
ii.For enclosures below the base flood elevation or future conditions flood elevations, location and total net area of foundation openings as required in this chapter.
iii.Proposed elevation in relation to mean sea level to which any non-residential structure will be flood-proofed;
iv.Certification that any proposed non-residential flood proofed structure meets the criteria of this chapter;
(3)Description of the extent to which any watercourse will be altered or relocated as a result of the proposed land development project; and
(4)Hard copies and digital files of computer models, if any, copies of work maps, comparison of pre and post development conditions base flood elevations, future conditions flood elevations, flood protection elevations, special flood hazard areas and regulatory floodway widths, flood profiles and all other computations and other information similar to that presented in the FIS;
(5)Copies of all necessary permits from governmental agencies from which approval is required by federal or state law, including but not limited to Section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1334, be provided and maintained on file; and
(6)All appropriate certifications required under this ordinance.
The approved floodplain management/flood damage prevention plan shall contain certification by the applicant that all development activities will be done according to the plan or previously approved revisions. Any and all development permits and/or use and occupancy certificates or permits may be revoked at any time if the construction and development activities are not in strict accordance with approved plans.
(e)Construction Stage Submittal Requirements.
(1)For all new construction and substantial improvements on sites with a floodplain management/flood damage prevention plan, the permit holder shall provide to the floodplain administrator a certified as-built elevation certificate or floodproofing certificate for non-residential construction including the lowest floor elevation or floodproofing level immediately after the lowest floor or floodproofing is completed. A final elevation certificate shall be provided after completion of construction including final grading of the site. Any lowest floor certification made relative to mean sea level shall be prepared by or under the direct supervision of a licensed land surveyor or professional engineer and certified by same. When floodproofing is utilized for non-residential structures, said certification shall be prepared by or under the direct supervision of a licensed professional engineer or architect and certified by same using the FEMA floodproofing certificate. This certification shall also include the design and operation/maintenance plan to assure continued viability of the floodproofing measures.
(2)Any work undertaken prior to approval of these certifications shall be at the permit holder's risk. The floodplain administrator shall review the above referenced certification data submitted. Deficiencies detected by such review shall be corrected by the permit holder immediately and prior to further work being allowed to proceed. Failure to submit certification or failure to make the corrections required hereby shall be cause to issue a stop work order for the project.
(f)Variances. A request for variance may be submitted by an applicant who has been denied a permit for development activity or by an owner or developer who has not applied for a permit because it is clear that the proposed development activity would be inconsistent with the provisions of this chapter. A request for variance shall be submitted through the Director of Community and Economic Development. All such requests shall be heard and decided in accordance with the procedures set forth in Chapter 18-6 and Chapter 20-3. At a minimum, such procedures shall include notice to all affected parties and the opportunity to be heard.
(1)Any person adversely affected by any decision of the Director of Community and Economic Development or the floodplain administrator shall have the right to appeal such decision to the Planning and Appeals Board as established by the city council with procedures to be published in writing by the planning and appeals board. At a minimum, such procedures shall include notice to all affected parties and the opportunity to be heard.
(2)Any person aggrieved by the decision of the Planning and Appeals Board may appeal such decision to a court of competent jurisdiction, as provided in O.C.G.A.
§ 5-4-1.
(3)Variances may be issued for the repair or rehabilitation of historic structures upon a determination that the proposed repair or rehabilitation will not preclude the structure's continued designation as an historic structure, and the variance issued shall be the minimum necessary to preserve the historic character and design of the structure.
(4)Variances may be issued for development necessary for the conduct of a functionally dependent use, provided the criteria of this section are met, no reasonable alternative exists, and the development is protected by methods that minimize flood damage during the base flood and create no additional threats to public safety.
(5)Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.
(6)In reviewing such requests, the city and the planning and appeals board shall consider all technical evaluations, relevant factors, and all standards specified in this and other sections of this chapter.
(7)Conditions for variances:
i.A variance shall be issued only when the requirements of the applicable chapter(s) have been met and there is:
A.A finding of good and sufficient cause;
B.A determination that failure to grant the variance would result in exceptional hardship; and
C.A determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, or the creation of a nuisance.
ii.The provisions of this chapter are minimum standards for flood loss reduction; therefore, any deviation from the standards must be weighed carefully. Variances shall only be issued upon determination that the variance is the minimum necessary, considering the flood hazard, to afford relief; and, in the instance of an historic structure, a determination that the variance is the minimum necessary so as not to destroy the historic character and design of the building.
iii.Any person to whom a variance is granted shall be given written notice specifying the difference between the base flood elevation and the elevation of the proposed lowest floor and stating that the cost of flood insurance resulting from the lowest floor elevation being placed below the base flood elevation will be commensurate with the increased risk to life and property, and that such costs may be as high or higher than $25 for each $100 of insurance coverage provided.
iv.The floodplain administrator shall maintain the records of all appeal actions and report any variances to the Federal Emergency Management Agency upon request.
(8)Any person requesting a variance shall, from the time of the request until the time the request is acted upon, submit such information and documentation as the city and the Planning and Appeals Board shall deem necessary to the consideration of the request.
(9)Upon consideration of the factors listed above and the purposes of this chapter, the city and the Planning and Appeals Board may attach such conditions to the granting of variances as they deem necessary or appropriate, consistent with the purposes of this chapter.
(10)Variances shall not be issued "after the fact."
(g)Enforcement. Enforcement of this chapter shall be as outlined in Chapter 20-2 and may include:
(1)Notice of Violation. If the Department of Water Resources determines that an applicant or other responsible person has failed to comply with the terms and conditions of a permit, an approved stormwater management plan or the provisions of this chapter, such department shall issue a written notice of violation to such applicant or other responsible person. Where a person is engaged in activity covered by this ordinance without having first secured a permit, the notice of violation shall be served on the owner or the responsible person in charge of the activity being conducted on the site. The notice of violation shall contain the following:
i.The name and address of the owner or the applicant or the responsible person;
ii.The address or other description of the site upon which the violation is occurring;
iii.A statement specifying the nature of the violation;
iv.A description of the remedial measures necessary to bring the action or inaction into compliance with the permit, the stormwater management plan or this chapter and the date for the completion of such remedial action;
v.A statement of the penalty or penalties that may be assessed against the person to whom the notice of violation is directed; and
vi.A statement that the determination of violation may be appealed to the Department of Water Resources by filing a written notice of appeal within 30 days after the notice of violation.
(2)Penalties. In the event the remedial measures described in the notice of violation have not been completed by the date set forth for such completion in the notice of violation, any one or more of the following actions or penalties may be taken or assessed against the person to whom the notice of violation was directed.
Before taking any of the following actions or imposing any of the following penalties, the Department of Water Resources or Community and Economic Development shall first notify the applicant or other responsible person in writing of its intended action, and shall provide a reasonable opportunity, of not less than 10 days (except, that in the event the violation constitutes an immediate danger to public health or public safety, 24-hour notice shall be sufficient) to cure such violation. In the event the applicant or other responsible person fails to cure such violation after such notice and cure period, the Department of Water Resources may take any one or more of the following actions or impose any one or more of the following penalties:
i.Administrative Penalties.
A.Stop work order. The Department of Water Resources or Department of Community and Economic Development may issue a stop work order which shall be served on the applicant or other responsible person. The stop work order shall remain in effect until the applicant or other responsible person has taken the remedial measures set forth in the notice of violation or has otherwise cured the violation or violations described therein, provided the stop work order may be withdrawn or modified to enable the applicant or other responsible person to take the necessary remedial measures to cure such violation or violations.
B.Withhold certificate of occupancy. The Department of Community and Economic Development may refuse to issue a certificate of occupancy for the building or other improvements constructed or being constructed on the site until the applicant or other responsible person has taken the remedial measures set forth in the notice of violation or has otherwise cured the violations described therein.
C.Suspension, revocation or modification of permit. The Department of Community and Economic Development may suspend, revoke or modify the permit authorizing the development project. A suspended, revoked or modified permit may be reinstated after the applicant or other responsible person has taken the remedial measures set forth in the notice of violation or has otherwise cured the violations described therein, provided such permit may be reinstated (upon such conditions as the Department of Water Resources may deem necessary) to enable the applicant or other responsible person to take the necessary remedial measures to cure such violations.
D.Civil penalties. In the event the applicant or otherwise responsible person fails to take the remedial measures set for in the notice of violation or otherwise fails to cure the violations described therein within 10 days (except, that in the event the violation constitutes and immediate danger to public health or public safety, 24-hour notice shall be sufficient) after the city has taken one or more of the administrative actions described above, the city may impose a penalty not to exceed one thousand dollars ($1,000.00) (depending on the severity or the violation) for each day the violation remains unremedied after receipt of the notice of violation.
ii.Criminal penalties. For intentional and flagrant violations or this chapter, the city may issue a citation to the applicant or other responsible person, requiring such person to appear in the city municipal court to answer charges for such violation. Upon conviction, such person shall be punished by a fine not to exceed one thousand dollars ($1,000.00) or imprisonment for 60 days or both. Each act of violation and each day upon which a violation shall occur shall constitute a separate offense.
§ 12-2-3
Standards for Development
(a)Definition of Floodplain Boundaries.
(1)Studied "A" zones, as identified in the FIS, shall be used to establish base flood elevations whenever available.
(2)For special flood hazards areas and flood prone areas, the future conditions flood elevations shall be determined by a registered professional engineer using FEMA approved methodology approved by the floodplain administrator.
(3)The boundaries or limits of the floodplain shall be within one-half (0.5) feet vertical accuracy on the site plan containing existing topographic information.
(b)Definition of Floodway Boundaries.
(1)The width of a floodway shall be determined from the FIS or FEMA approved flood study. For all streams with a drainage of 100 acres or greater the floodway shall be provided by the city. If unavailable then it shall be determined by a registered professional engineer using FEMA approved methodology approved by the floodplain administrator.
(2)The boundaries or limits of the floodway shall be shown on the development or stormwater site plan containing existing topographic information, as applicable.
(c)General Standards.
(1)No development shall be allowed within any area of special flood hazard or area of future conditions flood hazard that could result in any of the following:
i.Raising the base flood elevation or future conditions flood elevation equal to or more than one one-hundredth (0.01) foot;
ii.Reducing the base flood or future conditions flood storage capacity.
iii.Changing the flow characteristics of the waters of the base flood or future conditions flood as they pass both the upstream and the downstream boundaries of the property; or
iv.Creating hazardous or erosion-producing velocities, or resulting in excessive sedimentation.
(2)Any development within any area of special flood hazard or area of future-conditions flood hazard allowed under Title 9Section 12-2-3(c)(1) shall also meet the following conditions:
i.Compensation for storage capacity shall occur between the average ground water table elevation and the base flood elevation for the base flood, and between the average ground water table elevation and the future-condition flood elevation for the future-conditions flood, and lie either within the boundaries of ownership of the property being developed and shall be within the immediate vicinity of the location of the encroachment. Acceptable means of providing required compensation include lowering of natural ground elevations within the floodplain or lowering of adjoining land areas to create additional floodplain storage. In no case shall any required compensation be provided via bottom storage or by excavating below the elevation of the natural (pre-development) stream channel unless such excavation results from the widening or relocation of the stream channel.
ii.All cut areas are to be graded to a slope of no less than 2%.
iii.In all cases effective transitions must be provided such that flow velocities occurring on both upstream and downstream properties are not increased or decreased.
iv.Verification of no-rise conditions (0.01) foot or less), flood storage volumes, and flow characteristics shall be provided via a step-backwater analysis meeting the requirements of Title 9Section 12-2-3(d).
v.All proposed development shall have public utilities and facilities, such as sewer, gas, electrical and water system, located and constructed to minimize flood damage.
vi.Any significant changes or revisions to the flood data adopted herein and shown on the FIRM shall be submitted as a conditional letter of map revision (CLOMR) or conditional letter of map amendment (CLOMA), whichever is applicable. The CLOMR submittal shall be subject to approval by the floodplain administrator using the community consent forms before forwarding the submittal package to FEMA for final approval. The responsibility for forwarding the CLOMR to FEMA and for obtaining the CLOMR approval shall be the responsibility of the applicant. Within 6 months of the completion of construction, the applicant shall submit as built surveys which demonstrate general conformance to the approved designs as submitted in the CLOMR application. A letter of map revision (LOMR) or letter of map amendment (LOMA) must be issued before the final plat can be approved or a certificate of occupancy can be issued. Significant changes or revisions shall be defined as any change to the FIRM easily observed when plotted at a scale of 1" = 1000'. The changes or revisions may be due to, but are not limited to, more current and/or superior topographic information or compensatory cut and fill grading done as a part of the development.
(d)Engineering Study Requirements for Floodplain Encroachments. An engineering study is required, as appropriate to the proposed development activities on the site, whenever a development proposes to disturb the future conditions floodplain, except for a residential single-lot development on streams without established base flood elevations and floodways. This study shall be prepared by a currently registered professional engineer in the state and made a part of the application for a permit. This information shall be submitted to and approved by the floodplain administrator prior to the approval of any permit which would authorize the disturbance of land located within the floodplain. Such study shall include:
(1)Description of the extent to which any watercourse or floodplain will be altered or relocated because of the proposed development;
(2)Step-backwater analysis, using a FEMA approved methodology approved by the Department of Water Resources. Cross-sections (which may be supplemented by the applicant) and flow information will be obtained whenever available.
Computations will be shown duplicating FIS results and will then be rerun with the proposed modifications to determine the new base flood and future conditions flood profiles;
(3)Floodplain storage calculations based on cross-sections (at least one every 100 feet) showing existing and proposed floodplain conditions to show that the base flood floodplain and future conditions floodplain storage capacity would not be diminished by the development;
(4)If changes to the base flood elevation or future conditions flood elevation are proposed, profiles of the channel showing the existing and proposed base and future conditions flood elevations must be provided; and
(5)The study shall include a preliminary plat, grading plan, or site plan, as appropriate, which shall clearly define all future-conditions floodplain encroachments.
(e)Floodway Encroachments. Located within areas of special flood hazard are areas designated as floodway. A floodway may be an extremely hazardous area due to velocity flood waters, debris or erosion potential. In addition, floodways must remain free of encroachment to allow for the discharge of the base flood without increased flood heights. Therefore, the following provisions shall apply:
(1)Encroachments are prohibited, including earthen fill, new construction, substantial improvements or other development within the base floodway, except when required for the construction of bridges, culverts, roadways and utilities, provided it is demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the encroachment shall not result in any increase to the pre-project base flood elevations, floodway elevations, or floodway widths during the base flood discharge. A registered professional engineer must provide supporting technical data and certification thereof; and
(2)If the applicant proposes to revise the floodway boundaries, no permit authorizing the encroachment into or an alteration of the floodway shall be issued by the floodplain administrator until an affirmative conditional letter of map revision (CLOMR) or conditional letter of map amendment (CLOMA), whichever is applicable, is issued by FEMA, or a no-rise certification is approved by department of water resources.
(f)Maintenance Requirements. The property owner shall be responsible for continuing maintenance as may be needed within an altered or relocated portion of a floodplain on his property so that the flood-carrying or flood storage capacity is not diminished.
The floodplain administrator may direct the property owner, at no cost to the city, to restore the flood-carrying or flood storage capacity of the floodplain if the owner has not performed maintenance as required by the approved floodplain management plan on file with the department of water resources.
§ 12-2-4
Flood Hazard Reduction
(a)General Standards for Flood Hazard Reduction. In all areas of special flood hazard the following provisions apply:
(1)New construction of principal buildings (residential or non-residential), including manufactured homes, shall not be allowed within the limits of the floodplain unless all requirements of this chapter have been met;
(2)New construction or substantial improvements of existing structures shall be anchored to prevent flotation, collapse or lateral movement of the structure;
(3)New construction or substantial improvements of existing structures shall be constructed with materials and utility equipment resistant to flood damage; and
(4)New construction or substantial improvements of existing structures shall be constructed by methods and practices that minimize flood damage.
(b)Elevated Buildings.
(1)All new construction and substantial improvements of existing structures that include any fully enclosed area located below the lowest floor formed by foundation and other exterior walls shall be designed as an unfinished and flood resistant enclosure. The enclosure shall be designed to equalize hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwater.
(2)Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:
i.Provide 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;
ii.The bottom of all openings shall be no higher than one foot above grade;
and
iii.Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwater in both directions.
(3)So as not to violate the "lowest floor" criteria of this chapter, the unfinished or flood resistant enclosure shall only be used for parking of vehicles, limited storage of maintenance equipment used in connection with the premises, or entry to the elevated area; the interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(c)Service Facilities. All heating and air conditioning equipment and components, all electrical, ventilation, plumbing, and other service facilities shall be designed and/or located 3 feet above the base flood elevation or 1 foot above the future conditions flood elevation, whichever is higher, to prevent water from entering or accumulating within the components during conditions of flooding.
(d)Manufactured Homes.
(1)New manufactured homes shall not be allowed to be placed within the limits of the future- conditions floodplain unless all requirements of Title 9Section 12-2-3(b), (c), and (d) have been met. If all of the requirements of these sections have been met, all new construction and substantial improvement shall have the lowest floor, including basement, elevated no lower than 3 feet above the base flood elevation or 1 foot above the future-conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of subsection (b)(2) above.
(2)Manufactured homes placed and/or substantially improved in an existing manufactured home park or subdivision shall be elevated so that either:
i.The lowest floor of the manufactured home is elevated no lower than three feet above the level of the base flood elevation, or one foot above the future-conditions flood elevation, whichever is higher; or
ii.The manufactured home chassis is elevated and supported by reinforced piers (or other foundation elements of at least an equivalent strength) of no less than 36 inches in height above grade.
(3)Manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, the use of over-the-top or frame ties to ground anchors. This standard shall be in addition to and consistent with applicable State requirements for resisting wind forces.
(e)Water and Sewer Facilities and Other Utilities.
(1)New and 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 discharges from the systems into flood waters;
(3)Decentralized wastewater system shall be located outside the floodplain and constructed to avoid impairment to them or contamination from them during flooding.
(4)Other public utilities such as gas and electric systems shall be located and constructed to avoid impairment to them, or public safety hazards from them, during flooding.
(f)Nonconformities.
(1)Any alteration, repair, reconstruction or improvement to a structure which is not compliant with the provisions of this chapter, shall be undertaken only if the non-conformity is not furthered, extended or replaced.
(2)If the proposed development is located in multiple flood zones, or multiple base flood elevations cross the proposed site, the higher or more restrictive base flood elevation or future condition elevation and development standards shall take precedence.
(3)When only a portion of a proposed structure is located within a flood zone or the future conditions floodplain, the entire structure shall meet the requirements of this ordinance; and
(4)Subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, shall be reasonably safe from flooding:
i.All such proposals shall be consistent with the need to minimize flood damage within the flood-prone area;
ii.All public utilities and facilities, such as sewer, gas, electrical, and water systems shall be located and constructed to minimize or eliminate flood damage; and
iii.Adequate drainage shall be provided to reduce exposure to flood hazards.
(g)Residential Buildings Within Future Conditions Floodplains.
(1)New construction shall have the lowest floor, including any basement level, elevated no lower than 3 feet above the base flood elevation adjacent to the building or one foot above the future conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards of this chapter for elevated buildings.
(2)Substantial improvement of any structure or manufactured home shall have the lowest floor, including basement, elevated no lower than 3 feet above the base flood elevation adjacent to the building or one foot above the future conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards of this chapter for elevated buildings.
(h)Non-Residential Buildings Within the Future Conditions Floodplain.
(1)New construction shall have the lowest floor, including any basement level, elevated no lower than 1 foot above the base flood elevation or at least as high as the future conditions flood elevation. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of Title 9Section 12-2-4(b)(2)iii.
i.In lieu of the above, non-residential new construction may be authorized by the floodplain administrator to be constructed if it is determined that the structure shall be flood-proofed. The structure, together with attendant utility and sanitary facilities, must be designed to be water tight to 1 foot above the base flood elevation, or at least as high as the future conditions flood elevation, whichever is higher, with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions above, and shall provide such certification to the floodplain administrator using the FEMA floodproofing certificate along with the design and operation/maintenance plan.
(2)Substantial improvement of any structure located in A1-30, AE, or AH zones, may be authorized by the floodplain administrator to be elevated or flood- proofed.
Substantial improvements shall have the lowest floor, including basement elevated no lower than 1 foot above the base flood elevation or at least as high as the future conditions flood elevation, whichever is higher. Should solid perimeter walls be used to elevate the structure, openings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of Title 9Section 12-2-4(b)(2)iii.
i.In lieu of the above, substantial improvements may be constructed if it is determined that the structure will be flood-proofed. The structure, together with attendant utility and sanitary facilities, must be designed to be water tight to one foot above the base flood elevation, or at least as high as the future conditions flood elevation, whichever is higher, with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions above, and shall provide such certification to the floodplain administrator using the FEMA floodproofing certificate along with the design and operation/maintenance plan.
(i)Accessory Structures and Facilities in Future Conditions Floodplains. Accessory structures and facilities (i.e., barns, sheds, gazebos, detached garages, parking lots, recreational facilities and other similar structures and facilities) which are permitted to be located within the limits of the future conditions floodplain shall be designed and constructed to pass all floodwater in a manner consistent with this chapter and be anchored to prevent flotation, collapse or lateral movement of the structure.
(j)Standards for Recreational Vehicles in Floodplains. All recreational vehicles placed on sites must 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 licensed, on its wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached structures or additions); or
(2)The recreational vehicle must meet all the requirements for "Residential Buildings— Substantial Improvements", including the anchoring and elevation requirements above.
(k)Buildings and Structures Adjacent to the Future Conditions Floodplain.
(1)Residential buildings. For new construction or substantial improvement of any principal residential building or manufactured home, the elevation of the lowest floor, including basement and access to the building, shall be at least 3 feet above the level of the base flood (100-year) elevation or 1 foot higher than the future conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of Title 9Section 12-2-4(b).
(2)Non-residential buildings. For new construction or substantial improvement of any principal non-residential building, the elevation of the lowest floor, including basement and access to the building, shall be at least 1 foot above the level of the base flood (100-year) elevation or at least as high as the future conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of Title 9Section 12-2-4(b). Non-residential buildings may be floodproofed in lieu of elevation.
(l)Building Standards for Residential Single Lot Development for Streams Without Established Base Flood Elevations and/or Floodway (A-Zones).
(1)Located within the areas of special flood hazard, where streams exist but no base flood data have been provided (A-zones) or where base flood data have been provided but a floodway has not been delineated, the floodplain administrator shall review and reasonably utilize any available scientific or historic base flood elevation or regulatory flood elevation and floodway data, or future conditions flood elevation data available from a federal, state, or other source, in order to administer the provisions and standards of this section.
(2)If sufficient data are not available from these sources, the following provisions shall apply:
i.No encroachments, including structures or fill material, shall be located within an area equal to twice the width of the stream or 50 feet from the top of the bank of the stream, whichever is greater.
ii.In special flood hazard areas without base flood or future conditions flood elevation data, new construction and substantial improvements of existing structures shall have the lowest floor of the lowest enclosed area (including basement) elevated no less than 3 feet above the highest adjacent grade at the building site. Openings sufficient to facilitate the unimpeded movements of floodwaters shall be provided in accordance with the provisions of this chapter.
(m)Building Standards for Areas of Shallow Flooding (AO-Zones).
(1)Areas of special flood hazard may include designated "AO" shallow flooding areas. These areas have base flood depths of one to 3 feet above ground, with no clearly defined channel.
(2)In these areas the following provisions apply:
i.All new construction and substantial improvements of residential and non-residential structures shall have the lowest floor, including basement, elevated to no lower than one (foot above the flood depth number in feet specified on the flood insurance rate map (FIRM), above the highest adjacent grade. If no flood depth number is specified, the lowest floor, including basement, shall be elevated at least 3 feet above the highest adjacent grade.
Openings sufficient to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards for "elevated buildings." The applicant's or owner's engineer shall certify to the floodplain administrator that the lowest floor elevation level and the record shall become a permanent part of the permit file;
ii.New construction and substantial improvement of a non-residential structure may be flood-proofed in lieu of elevation. The structure, together with attendant utility and sanitary facilities, must be designed to be water tight to the specified FIRM flood level plus one foot above the highest adjacent grade, with walls substantially impermeable to the passage of water, and structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. A registered professional engineer or architect shall certify that the design and methods of construction are in accordance with accepted standards of practice; and shall provide such certification to the department of water resources using the FEMA floodproofing certificate along with the design and operation/maintenance plan; and
iii.Drainage paths shall be provided to guide floodwater around and away from any proposed structure.
(n)Standards for Subdivisions.
(1)All subdivision proposals shall identify the special flood hazard area and areas of future conditions flood hazard therein and provide base flood and future conditions flood elevation data future conditions flood elevation data;
(2)All residential lots in a subdivision proposal shall have sufficient buildable area outside of the future conditions floodplain such that encroachments into the future conditions floodplain for residential structures will not be required;
(3)All subdivision plans will provide the elevation of proposed structure(s) and pad(s). If the site is filled above the base flood or future conditions flood elevation, the lowest flood and pad elevations shall be certified by a registered professional engineer or surveyor and provided to the floodplain administrator;
(4)All subdivision proposals shall be consistent with the need to minimize flood damage;
(5)All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage; and,
(6)All subdivision proposals shall have adequate drainage provided to reduce exposure to flood hazards.