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Article 7-8-10 — Floodplain Management and Flood Damage Prevention

Code as publishedas of 2026-03-11

Our copychecked 2026-10-19 · matches Marietta's file

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§ 7-8-10-010

General provisions.

A.Purpose and Intent. The purpose of this article is 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, streambank and stream corridor protection, wetlands preservation and ecological and environmental protection by provisions designed to:

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

2.Restrict or prohibit uses which are dangerous to health, safety and property due to flooding or erosion hazards, or which increase flood heights, velocities, or erosion;

3.Control filling, grading, dredging and other development which may increase flood damage or erosion;

4.Prevent or regulate the construction of flood barriers which will unnaturally divert flood waters or which may increase flood hazards to other lands;

5.Limit the alteration of natural floodplains, stream channels, and natural protective barriers; which are involved in the accommodation of flood waters; and

6.Protect the stormwater management, water quality, streambank protection, stream corridor protection, wetland preservation and ecological functions of natural floodplain areas.

B.[Reserved.]

C.Applicability. This article shall be applicable to all areas within the city.

D.Designation of Article Administrator. The public works director or his/her designee is hereby appointed to administer and implement the provisions of this article.

E.Basis for Areas of Special Flood Hazard, Areas of Future-Conditions Flood Hazard and Associated Floodplain Characteristics—Flood Area Maps and Studies. For the purposes of defining and determining "areas of special flood hazard," "areas of future-conditions flood hazard," "areas of shallow flooding," "base flood elevations," "floodplains," "floodways," "future-conditions flood elevations," "future-conditions floodplains," potential flood hazard or risk categories as shown on FIRM maps, and other terms used in this article, the following documents and sources may be used for such purposes and are adopted by reference thereto:

1.The Flood Insurance Study (FIS), dated December 16, 2008, November 2, 2012, March 4, 2013, and October 5, 2018 as applicable for the panel, or latest revision, with accompanying maps, and other supporting data and any revision thereto. For those land areas acquired by the city through annexation, the current effective FIS and data for Cobb County, as noted above, with accompanying maps and other supporting data and any revision thereto.

2.Other studies which may be relied upon for the establishment of the base flood elevation or delineation of the base or one-percent (100-year) floodplain and flood-prone areas, including:

a.Any flood or flood-related study conducted by the United States Army Corps of Engineers, or the United States Geological Survey, or any other local, state or federal agency applicable to the city; and

b.Any base flood study conducted by a licensed professional engineer which has been prepared utilizing FEMA-approved methodology and approved by the city.

3.Other studies which may be relied upon for the establishment of the future-conditions floodplain elevation or delineation of the future-conditions floodplain and flood-prone areas including:

a.Any flood or flood-related study conducted by the United States Army Corps of Engineers, or the United States Geological Survey or any other local, state or federal agency applicable to the city; and

b.Any future-conditions flood study conducted by a licensed professional engineer which has been prepared utilizing FEMA-approved methodology and approved by the city.

4.The repository for public inspection of the FIS, accompanying maps and other supporting data is located at the office of the public works director or designee.

F.Compatibility with Other Regulations. This article 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 article are in addition to the requirements of any other ordinance, rule, regulation or other provision of law, and where any provision of this article imposes restrictions different from those imposed by any other ordinance, rule, regulation or other provision of law, whichever provision is more restrictive or imposes higher protective standards for human health or the environment shall control.

G.Severability. If the provisions of any section, subsection, paragraph, subdivision or clause of this article 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 article.

H.Warning and Disclaimer of Liability. The degree of flood protection required by this article is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur; flood heights may be increased by manmade or natural causes. This article 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 article shall not create liability on the part of the city or by any officer or employee thereof for any flood damages that result from reliance on this article or any administrative decision lawfully made there under. (Ord. No. 8052, 10/10/2018, § 1)

§ 7-8-10-020

Definitions.

"Accessory structure or facility" means a structure which is on the same parcel of property as the principal structure and the use of which is incidental to the use of the primary structure.

"Addition" means any walled and roofed expansion to the perimeter or height of a building.

"Adjacent" means those areas located within the defined horizontal distance from the future-conditions floodplain boundary that are at or lower in elevation than either three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher, unless the area is hydraulically independent (meaning absolutely no connection to the flooding source such as through pipes, sewer laterals, down drains, foundation drains, ground seepage, overland flow, gated or valved pipes, excavated and backfilled trenches, etc. with no fill or other manmade barriers creating the separation).

"Appeal" means a request for a review by the public works director's or designee's interpretation of any provision of this article.

"Area of future-conditions flood hazard" means the land area that would be inundated by the one-percent-annual-chance flood based on future-conditions hydrology (100-year future-conditions flood).

"Area of shallow flooding" means a designated AO or AH Zone on a community's flood insurance rate map (FIRM) with a one percent or greater 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 indeterminate, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.

"Area of special flood hazard" is the land in the floodplain subject to a one percent or greater chance of flooding in any given year. This includes all floodplain and flood prone areas at or below the base flood elevation (including A, A1-30, A-99, AE, AO, AH, and AR on a community's flood insurance rate map (FIRM).

"Base flood" means the flood having a one percent chance of being equaled or exceeded in any given year, also known as the "100-year flood".

"Base flood elevation" means the highest water surface elevation anticipated at any given location during the base flood.

"Basement" means any area of a building having its floor sub-grade below ground level on all sides.

"Building" has the same meaning as "structure".

"Development" means any man-made change to improved or unimproved real estate including but not limited to buildings or other structures, mining, dredging, filling, clearing, grubbing, grading, paving, any other installation of impervious cover, excavation or drilling operations or storage of equipment or materials.

"Elevated building" means a non-basement building which has its lowest elevated floor raised above the ground level by foundation walls, shear walls, posts, piers, pilings, or columns.

"Existing construction" means any structure for which the "start of construction" commenced before January 11, 1978.

"Existing manufactured home park or subdivision" means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, construction of streets, and final site grading or the pouring of concrete pads) is completed before January 11, 1978.

"Expansion to an existing manufactured home park or subdivision" means the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed, (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) was completed before January 11, 1978.

"FEMA" means the Federal Emergency Management Agency.

"Flood" or "flooding" means a general and temporary condition of partial or complete inundation of normally dry land areas from:

(a)The overflow of inland or tidal waters; or

(b)The unusual and rapid accumulation or runoff of surface waters from any source.

"Flood insurance rate map" or "FIRM" means an official map of a community, issued by the Federal Emergency Management Agency, delineating the areas of special flood hazard and/or risk premium zones applicable to the community.

"Flood insurance study" or "FIS" means the official report by FEMA providing an evaluation and determination of flood hazards and corresponding flood profiles and water surface elevations of the base flood.

"Floodplain" or "flood-prone area" means any land area susceptible to flooding.

"Floodproofing" means any combination of structural and 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.

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

"Functionally dependent use" means a use which cannot perform its intended purpose unless it is located or carried out in close proximity to water. The term includes only docking facilities, port facilities that are necessary for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does not include long-term storage or related manufacturing facilities.

"Future-conditions flood" means the flood having a one percent chance of being equaled or exceeded in any given year based on future-conditions hydrology. Also known as the 100-year future-conditions flood.

"Future-conditions flood elevation" means the highest water surface elevation anticipated at any given location during the future-conditions flood.

"Future-conditions floodplain" means any land area susceptible to flooding by the future-conditions flood.

"Future-conditions hydrology" means the flood discharges associated with projected land-use conditions based on a community's zoning map, comprehensive land-use plans, and/or watershed study projections, and without consideration of projected future construction of flood detention structures or projected future hydraulic modifications within a stream or other waterway, such as bridge and culvert construction, fill, and excavation.

"Highest adjacent grade" means the highest natural elevation of the ground surface, prior to construction next to the proposed walls of a structure.

"Historic structure" means any structure that is:

(a)Listed individually in the National Register of Historic Places (a listing maintained by the U.S. Department of Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the national register;

(b)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 of the Interior to qualify as a registered historic district;

(c)Individually listed on a state inventory of historic places by states with historic preservation programs which have been approved by the Secretary of the Interior; or

(d)Individually listed on a local inventory of historic places by communities with historic preservation programs that have been certified either:

1.By an approved state program as determined by the Secretary of the Interior; or

2.Directly by the Secretary of the Interior in states without approved programs.

"Lowest floor" means the lowest floor of the lowest enclosed area, including basement. An unfinished or flood-resistant enclosure, usable solely for parking of vehicles, building access, or storage, in an area other than a basement area, is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of other provisions of this article.

"Manufactured home" means a building, transportable in one or more sections, which is built on a permanent chassis and is designed to be used with or without a permanent foundation when connected to the required utilities. The term includes any structure commonly referred to as a "mobile home" regardless of the date of manufacture. The term also includes parked trailers, travel trailers and similar transportable structures placed on a site for 180 consecutive days or longer and intended to be improved property. The term does not include a "recreational vehicle".

"Mean sea level" means the datum to which base flood elevations shown on a community's flood insurance rate map (FIRM) are referenced. For purposes of this article the term is synonymous with National Geodetic Vertical Datum (NGVD) of 1929 or the North American Vertical Datum (NAVD) of 1988.

"New construction" means any structure (see definition) for which the "start of construction" commenced on or after January 11, 1978, and includes any subsequent improvements to the structure.

"New manufactured home park or subdivision" means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed on or after January 11, 1978.

"Owner" means the legal or beneficial owner of a site, including but not limited to, a mortgagee or vendee in possession, receiver, executor, trustee, lessee or other person, firm or corporation in control of the site.

"Permit" means the permit issued by the public works department to the applicant which is required for undertaking any land development activity.

"Recreational vehicle" means a vehicle which is:

(a)Built on a single chassis;

(b)400 square feet or less when measured at the largest horizontal projection;

(c)Designed to be self-propelled or permanently towable by light duty truck; and

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

"Repetitive loss" means flood-related damage sustained by a structure on two separate occasions during a ten-year period for which the cost of repairs at the time of each such flood event, on the average, equals or exceeds 25 percent of the market value of the structure before the damage occurred.

"Site" means the parcel of land being developed, or the portion thereof on which the land development project is located.

"Start of construction" includes substantial improvement, and means the date the permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition placement, or other improvement was within 180 days of the permit date. The actual start means either the first placement of permanent construction of the structure on a site, such as the pouring of slabs or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation, and includes the placement of a manufactured home on a foundation. Permanent construction does not include initial land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings such as garages or sheds not occupied as dwelling units or part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

"Structure" means a walled and roofed building (including a gas or liquid storage tank) that is principally above ground, or a manufactured home.

"Subdivision" means the division of a tract or parcel of land resulting in one or more new lots or building sites for the purpose, whether immediately or in the future, of sale, other transfer of ownership or land development, and includes divisions of land resulting from or made in connection with the layout or development of a new street or roadway or a change in an existing street or roadway.

"Substantial damage" means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred. This term also includes "repetitive loss".

"Substantial improvement" means any reconstruction, rehabilitation, addition, or other improvement to a structure, taking place during a ten-year period, in which the cumulative cost equals or exceeds 50 percent of the market value of the structure prior to the improvement. The market value of the building means (1) the appraised value of the structure prior to the start of the initial repair or improvement, or (2) in the case of damage, the value of the structure prior to the damage occurring. This term includes structures which have incurred "substantial damage", regardless of the actual repair work performed. The term does not, however, include those improvements of a structure required to comply with existing state or local health, sanitary, or safety code specifications which are the minimum necessary to assure safe living condi-tions, which have been identified by the chief building official. The term does also not include any alteration of a historic structure, provided that the alteration will not preclude the structure's continued designation as a historic structure.

"Substantially improved existing manufactured home park or subdivision" means the repair, reconstruction, rehabilitation or improvement of the streets, utilities and pads equals or exceeds 50 percent of the value of the streets, utilities and pads before the repair, reconstruction or improvement commenced.

"Variance" means a grant of relief from the requirements of this article.

"Violation" means the failure of a structure or other development to be fully compliant with the requirements of this article. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance required in this article is presumed to be in violation until such time as that documentation is provided. (Ord. No. 8052, 10/10/2018, § 1)

§ 7-8-10-030

Permit procedures and requirements.

A.Permit Application Requirements. No owner or developer shall perform any land 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 article prior to commencing the proposed activity.

Unless specifically excluded by this article, any landowner or developer desiring a permit for a land development activity shall submit to the public works director or designee a permit application on a form provided by him for that purpose. No land development permit will be approved for any land development activities that do not meet the requirements, restrictions and criteria of this article.

No permit will be approved for any development activities that do not meet the requirements, restrictions and criteria of this article.

B.Floodplain Management Plan Requirements. An application for a development project with any area of special flood hazard or area of future-conditions flood hazard located on the site shall include a floodplain management/flood damage prevention plan. This plan shall include the following items:

1.Site plan drawn to scale, which includes but is not limited to:

a.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;

b.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;

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

d.Proposed locations of drainage and stormwater management facilities;

e.Proposed grading plan;

f.Base flood elevations and future-conditions flood elevations;

g.Boundaries of the base flood floodplain and future-conditions floodplain;

h.If applicable, the location of the floodway; and

i.Certification of the above by a licensed professional engineer or surveyor.

2.Building and foundation design detail, including but not limited to:

a.Elevation in relation to mean sea level (or highest adjacent grade) of the lowest floor, including basement, of all proposed structures;

b.Elevation in relation to mean sea level to which any non-residential structure will be floodproofed;

c.Certification that any proposed non-residential floodproofed structure meets the criteria in Section 7-8-10-050 B.2.;

d.For enclosures below the base flood elevation, location and total net area of foundation openings as required in Section 7-8-10-050 A.5.a; and

e.Design plans certified by a licensed professional engineer or architect for all proposed structure(s).

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

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 floodways, flood profiles and all other computations and other information similar to that presented in the FIS;

5.Copies of all applicable state and federal permits necessary for proposed development including but not limited to permits required by Section 404 of the Federal Water Pollution Control Act, Amendments of 1972, 33 U.S.C. § 1334; and

6.All appropriate certifications required under this article.

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.

C.Construction Stage Submittal Requirements. For all new construction and substantial improvements on sites with a floodplain management/flood damage prevention plan, the permit holder shall provide to the public works director or designee a certified as-built FEMA 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. 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 licensed 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.

Any work undertaken prior to approval of these certifications shall be at the permit holder's risk. The public works director or designee 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.

D.Duties and Responsibilities of the Public Works Director or His/Her Designee. Duties of the public works director or designee shall include, but shall not be limited to:

1.Review all land development applications and permits to assure that the requirements of this article 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 public works director or designee 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 Sections 7-8-10-040 and 7-8-10-050;

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 floodproofed;

6.When floodproofing is utilized for a structure, the public works director or designee shall review the design and operation/maintenance plan and obtain certification from a licensed professional engineer or architect;

7.Notify affected adjacent communities and the Georgia Department of Natural Resources (DNR) 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 public works director or designee 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 article. 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 article shall be maintained in the office of the public works director or designee and shall be open for public inspection;

10.Coordinate all FIRM revisions with the Georgia DNR and FEMA; and

11.Review variance applications and make recommendations to city council.

(Ord. No. 8052, 10/10/2018, § 1)

§ 7-8-10-040

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 all streams with a drainage area of 100 acres or greater, the available future-conditions flood elevations shall be provided by the public works director or designee. If future-conditions elevation data is not available from the public works director or designee, then it shall be determined by a licensed professional engineer using a method approved by FEMA and the public works director or designee.

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 area of 100 acres or greater, the regulatory floodway shall be provided by the public works director or designee. If floodway data is not available from the public works director or designee, then it shall be determined by a licensed professional engineer using a method approved by FEMA and the public works director or designee.

2.Following a pre-design conference with the public works director or designee, the boundaries or limits of the floodway shall be shown on the (development or stormwater) site plan containing existing topographic information.

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:

a.Raising the base flood elevation or future-conditions flood elevation equal to or more than 0.01 foot;

b.Reducing the base flood or future-conditions flood storage capacity;

c.Changing the flow characteristics as to the depth and velocity of the waters of the base flood or future-conditions flood as they pass both the upstream and the downstream boundaries of the development area; or

d.Creating hazardous or erosionproducing velocities, or resulting in excessive sedimentation.

2.Any development within any area of special flood hazard or area of the future-conditions flood hazard allowed above shall also meet the following conditions:

a.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-conditions 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 top of the natural (pre-development) stream channel unless such excavation results from the widening or relocation of the stream channel;

b.Cut areas shall be stabilized and graded to a slope of no less than 2.0 percent;

c.Effective transitions shall be provided such that flow velocities occurring on both upstream and downstream properties are not increased or decreased;

d.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 Section 7-8-10-040 D.;

e.Public utilities and facilities, such as water, sanitary sewer, gas, and electrical systems, shall be located and constructed to minimize or eliminate infiltration or contamination from flood waters; and

f.Any significant physical changes to the base flood floodplain 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 public works director or designee 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 six months of the completion of, the applicant shall submit as-built surveys and plans for a final letter of map revision (LOMR).

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 any land within 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 licensed professional engineer and made a part of the application for a permit. This information shall be submitted to and approved by the public works director or designee prior to the approval of any permit which would authorize the disturbance of land located within the future-conditions floodplain. Such study shall include:

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

2.Step-backwater analysis, using a FEMA-approved methodology approved by the public works director or designee. 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 base flood floodplain and future-conditions floodplain storage capacity would not be diminished by the development; and

4.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, flood-ways must remain free of encroachment in order 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 regulatory floodway, except for activities specifically allowed in Subsection 2. below.

2.Encroachments for bridges, culverts, roadways and utilities within the regulatory floodway may be permitted provided it is demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the encroachment will not result in any increase to the pre-project base flood elevations, floodway elevations, or floodway widths during the base flood discharge. A licensed professional engineer must provide supporting technical data and certification thereof; and

3.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 public works director or designee until an affirmative conditional letter of map revision (CLOMR) is issued by FEMA or a no-rise certification is approved by the public works director or designee.

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 the property so that the flood-carrying or flood storage capacity is not diminished. The public works director or designee 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 public works director or designee.

The property owner's failure to maintain facilities will be considered a violation of this article. (Ord. No. 8052, 10/10/2018, § 1)

§ 7-8-10-050

Provisions for flood damage reduction.

A.General Standards. In all areas of special flood hazard and areas of future-conditions flood hazard the following provisions apply:

1.New construction and substantial improvements of structures (residential or non-residential), including manufactured homes, shall not be allowed within the limits of the future-conditions floodplain unless all requirements of Subsections 7-8-10-040 C., D. and E.

have been met;

2.New construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure;

3.New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage;

4.New construction and substantial improvements shall be constructed by methods and practices that minimize flood damage;

5.Elevated buildings. All new construction and substantial improvements that include any fully enclosed area located below the lowest floor formed by foundation and other exterior walls shall be designed so as to be an unfinished or 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 flood water.

a.Designs for complying with this requirement must either be certified by a licensed professional engineer or architect or exceed the following minimum criteria:

(1)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;

(2)The bottom of all openings shall be no higher than one foot above grade; and

(3)Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of flood water in both directions.

b.So as not to violate the "lowest floor" criteria of this article, the unfinished or flood-resistant enclosure shall solely be used for parking of vehicles, limited storage of maintenance equipment used in connection with the premises, or entry to the elevated area; and

c.The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.

6.All heating and air conditioning equipment and components (including ductwork), all electrical, ventilation, plumbing, and other service facilities shall be designed and/or located three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher, so as to prevent water from entering or accumulating within the components during conditions of flooding;

7.Manufactured homes shall be anchored to prevent flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This standard shall be in addition to and consistent with applicable State of Georgia requirements for resisting wind forces;

8.All proposed development shall include adequate drainage and stormwater management facilities per the requirements of the city to reduce exposure to flood hazards;

9.New and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system;

10.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;

11.On-site waste disposal systems shall be located and constructed to avoid impairment to, or contamination from, such systems during flooding;

12.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;

13.Any alteration, repair, reconstruction or improvement to a structure which is not compliant with the provisions of this article, shall be undertaken only if the nonconformity is not furthered, extended or replaced;

14.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;

15.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 article; and

16.Subdivision proposals and other proposed new development, including manufactured home parks or subdivisions, shall be reasonably safe from flooding:

a.All such proposals shall be consistent with the need to minimize flood damage within the flood-prone area;

b.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

c.Adequate drainage shall be provided to reduce exposure to flood hazards.

B.Building Standards for Structures and Buildings Within the Future-Conditions Floodplain.

1.Residential Buildings.

a.New Construction. New construction of principal residential structures shall not be allowed within the limits of the futureconditions floodplain unless all requirements of Subsections 7-8-10-040 C., D. and E. have been met. If all of the requirements of Subsections 7-8-10-040 C., D. and E. have been met, all new construction shall have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to equalize the hydrologic flood forces on exterior walls and to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards of Subsection 7-8-10-050 A.5.a.

b.Substantial Improvements.

Substantial improvement of principal residential structures shall not be allowed within the limits of the futureconditions floodplain unless all requirements of Subsections 7-8-

10-040 C., D. and E. have been met.

If all of the requirements of Subsec-tions 7-8-10-040 C., D. and E. have been met, all substantial improve-ments shall have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation or one foot above the future-conditions flood elevation, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, openings sufficient to equalize the hydrostatic flood forces on exterior walls and to facilitate the unimpeded movements of flood waters shall be provided in accordance with standards of Subsection 7-8-10-050 A.5.a.

2.Non-Residential Buildings.

a.New Construction. New construction of principal non-residential structures shall not be allowed within the limits of the futureconditions floodplain unless all requirements of Subsections 7-8-10-040 C., D and E. have been met. If all of the requirements of Subsections 7-8-10-040 C., D. and E. have been met, all new construction shall have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation or one 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 7-8-10-050 A.5.a. New construction that has met all of the requirements of Subsections 7-8-10-040 C., D., and E. may be floodproofed in lieu of elevation. The structure, together with attendant utility and sanitary facilities, must be designed to be watertight 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 licensed 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 using the FEMA floodproofing certificate along with the design and operation/ maintenance plan to the public works director or designee.

b.Substantial Improvements.

Substantial improvements of principal non-residential structures shall not be allowed within the limits of the futureconditions floodplain unless all requirements of Subsec-tions 7-8-10-040 C., D. and E. have been met. If all of the requirements of Subsections 7-8-10-040 C., D. and

E.have been met, all substantial improvements shall have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation or one foot above the future-conditions flood eleva-tion, whichever is higher. Should solid foundation perimeter walls be used to elevate the structure, open-ings sufficient to automatically equalize the hydrostatic flood forces on exterior walls shall be provided in accordance with standards of Subsection 7-8-10050 A.5.a.

Substantial improvement hat has met all of the requirements of Subsections 7-8-10-040 C., D. and

E.may be floodproofed in lieu of elevation. The structure, together with attendant utility and sanitary facilities, must be designed to be watertight 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 licensed 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 using the FEMA floodproofing certificate along with the design and operation/ maintenance plan to the public works director or designee.

3.Accessory Structures and Facilities. Accessory structures and facilities (i.e., bams, sheds, gazebos, detached garages, recreational facilities and other similar non-habitable structures and facilities) which meet the requirements of Subsections 7-8-10-040 C., D. and E. and are permitted to be located within the limits of the future-conditions floodplain shall be constructed of flood-resistant materials and designed to provide adequate flood openings in accordance with Subsection 7-8-10-050 A.5.a. and be anchored to prevent flotation, collapse and lateral movement of the structure.

4.Standards for Recreational Vehicles. All recreational vehicles placed on sites must either:

a.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

b.Meet all the requirements for Residential Buildings - Substantial Improvements Subsection 7-8-10050 B.l.b, including the anchoring and elevation requirements.

5.Standards for Manufactured Homes.

a.New manufactured homes shall not be allowed to be placed within the limits of the future-conditions floodplain unless all requirements of Subsections 7-8-10040 C., D. and E. have been met. If all of the requirements of Subsections 7-8-10040 C., D. and E. have been met, all new construction and substantial improvement shall have the lowest floor, including basement, elevated no lower than three feet above the base flood elevation or one 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 7-8-10-050 A.5.a.

b.Manufactured homes placed and/or substantially improved in an existing manufactured home park or subdivision shall be elevated so that:

(1)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.

c.All manufactured homes must be securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement in accordance with standards of Subsection 7-8-10-050 A.7.

C.Building Standards for Structures and Buildings Authorized Adjacent to the Future-Conditions Floodplain.

1.Residential Buildings. For new construction and 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 three feet above the level of the base flood elevation or one 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 7-8-10-050 A.5.a.

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 three feet above the level of the base flood 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 Subsection 7-8-10-050 A.5.a.

D.Building Standards Residential Single-Lot Developments on Streams Without Established Base Flood Elevations and/or Floodway (A-Zones). For a residential single-lot development not part of a subdivision that has areas of special flood hazard, where streams exist but no base flood data have been provided (A-Zones), the public works director or designee shall review and reasonably utilize any available scientific or historic flood elevation data, base flood elevation and floodway data, or future-conditions flood elevation data available from a federal, state, local or other source, in order to administer the provisions and standards of this article.

If data are not available from any of these sources, the following provisions shall apply:

1.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.

2.In special flood hazard areas without base flood or future-conditions flood elevation data, new construction and substantial improvements shall have the lowest floor of the lowest enclosed area (including basement) elevated no less than three feet above the highest adjacent grade at the building site. Flood openings sufficient to facilitate automatic equalization of hydrostatic flood forces shall be provided for flood prone enclosures in accordance with Subsection 7-8-10050 A.5.a.

E.Building Standards for Areas of Shallow Flooding (AO-Zones). Areas of special flood hazard may include designated "AO" shallow flooding areas. These areas have base flood depths of one to three feet above ground, with no clearly defined channel. In these areas the following provisions apply:

1.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 three feet above the highest adjacent grade. Openings sufficient to facilitate automatic equalization of hydrostatic flood forces shall be provided in accordance with standards of Subsection 7-8-10-050 A.5.

2.New construction and substantial improvement of a non-residential structure may be floodproofed in lieu of elevation. The structure, together with attendant utility and sanitary facilities, must be designed to be watertight 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 licensed 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 using the FEMA floodproofing certificate along with the design and operation/maintenance plan to the public works director or designee; and

3.Drainage paths shall be provided to guide flood water around and away from any proposed structure.

F.Standards for Subdivisions of Land.

1.All subdivision proposals shall identify the areas of special flood hazard and areas of future-conditions flood hazard and provide base flood elevation data and 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 elevations of proposed structures in accordance with Subsection 7-8-10-030 B.2.;

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 water, sanitary sewer, gas, and electrical systems located and constructed to minimize or eliminate infiltration of flood waters, and discharges from the systems into flood waters; and

6.All subdivision proposals shall have adequate drainage and stormwater management facilities per the requirements of the public works department to reduce exposure to flood hazards.

G.Standards for Utilities.

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

a.Infiltration of flood waters into the systems; and

b.Discharges from the systems into flood waters.

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

(Ord. No. 8052, 10/10/2018, § 1; Ord. No. 8275, 5/11/2022, § 1; Ord. No. 8354, 10/11/23, § 1)

§ 7-8-10-060

Variance procedures.

The following variance and appeals procedures shall apply to an applicant who has been denied a permit for a development activity, or to 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 article.

A.Requests for variances from the requirements of this article shall be submitted to the city council. All such requests shall be heard and decided in accordance with procedures to be published in writing by the city council. At a minimum, such procedures shall include notice to all affected parties and the opportunity to be heard.

B.Any person adversely affected by any decision of the city council shall have the right to appeal such decision to the Cobb County Superior Court in accordance with procedures to be published in writing by the city council. At a minimum, such procedures shall include notice to all affected parties and the opportunity to be heard.

C.Any person aggrieved by the decision of the city council may appeal such decision to the Cobb County Superior Court, as provided in Section 5-4-1 of the Official Code of Georgia Annotated.

D.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.

E.Variances may be issued for development necessary for the conduct of a functionally dependent use, provided the criteria of this article 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.

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

G.In reviewing such requests, the city council shall consider all technical evaluations, relevant factors, and all standards specified in this and other sections of this article.

H.Conditions for Variances.

1.A variance shall be issued only when 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, create nuisance, or cause fraud on or victimization of the public.

2.The provisions of this article 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 considering the flood hazard, to afford relief;

3.Any person to whom a variance is granted shall be given written notice by the city council 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 as $25.00 for each $100.00 of insurance coverage provided; and

4.The public works director or designee shall maintain the records of all variance actions, both granted and denied, and report them to the Georgia Department of Natural Resources and the Federal Emergency Management Agency upon request.

I.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 public works director or designee and city council shall deem necessary to the consideration of the request.

J.Upon consideration of the factors listed above and the purposes of this article, the city council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this article.

K.Variances shall not be issued "after the fact".

(Ord. No. 8052, 10/10/2018, § 1)

§ 7-8-10-070

Violations, enforcement and penalties.

Any action or inaction which violates the provisions of this article or the requirements of an approved stormwater management plan or permit, may be subject to the enforcement actions outlined in this article. Any such action or inaction which is continuous with respect to time is deemed to be a public nuisance and may be abated by injunctive or other equitable relief. The imposition of any of the penalties described below shall not prevent such equitable relief.

A.Notice of Violation. If the public works director or designee 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 article, it shall issue a written notice of violation to such applicant or other responsible person. Where a person is engaged in activity covered by this article without having first secured a permit therefore, 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:

1.The name and address of the owner or the applicant or the responsible person;

2.The address or other description of the site upon which the violation is occurring;

3.A statement specifying the nature of the violation;

4.A description of the remedial measures necessary to bring the action or inaction into compliance with the permit, the stormwater management plan or this article and the date for the completion of such remedial action;

5.A statement of the penalty or penalties that may be assessed against the person to whom the notice of violation is directed; and

6.A statement that the determination of violation may be appealed to the city council by filing a written notice of appeal within 30 days after the notice of violation except, that in the event the violation constitutes an immediate danger to public health or public safety, 24 hours' notice shall be sufficient.

B.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 public works director or designee 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 ten days, (except that in the event the violation constitutes an immediate danger to public health or public safety, 24 hours' 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 public works director or designee may take any one or more of the following actions or impose any one or more of the following penalties.

1.Stop-Work Order. The public works director or designee 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.

2.Withhold Certificate of Occupancy. The public works director or designee 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.

3.Suspension, Revocation or Modification of Permit. The public works director or designee may suspend, revoke or modify the permit authorizing the land 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 public works director or designee may deem necessary, to enable the applicant or other responsible person to take the necessary remedial measures to cure such violations.

4.Civil Penalties. In the event the applicant or other responsible person fails to take the remedial measures set forth in the notice of violation or otherwise fails to cure the violations described therein within ten days, or such greater period as the public works director or designee shall deem appropriate, except that in the event the violation constitutes an immediate danger to public health or public safety 24 hours' notice shall be sufficient, or for intentional and flagrant violations of this article, the public works director or designee may issue a citation to the applicant or other responsible person, requiring such person to appear in municipal court to answer charges for such violation. Upon conviction, such person shall be punished by a fine not to exceed $1,000.00 or imprisonment for 60 days or both, and in addition, shall pay all costs and expenses involved in the case.

Each act of violation and each day upon which any violation shall occur shall constitute a separate offense.

5.Criminal Penalties. For intentional and flagrant violations of this article, the public works director or designee may issue a citation to the applicant or other responsible person, requiring such person to appear in municipal court to answer charges for such violation. Upon conviction, such person shall be punished by a fine not to exceed $1,000.00 or imprisonment for 60 days or both. Each act of violation and each day upon which any violation shall occur shall constitute a separate offense.

(Ord. No. 8052, 10/10/2018, § 1)

ARTICLE 7-8-12 SOIL EROSION, SEDIMENTATION AND POLLUTION

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