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Henry County, GA

Contact henry County Government
347 Phillips Drive
McDonough, GA 30253
Tel: (770) 288-7246
Tel: (770) 288-RAIN
Fax: (770) 288-7257

Hours:
Mon - Fri: 7:30a - 4:30p

 




Floodplain Management

Flood Map

The Henry County Stormwater Management is a division of Public Works responsible for the review, and approval of all stormwater facilities. The goal of Stormwater Management is to promote and protect the health, safety, and welfare of the public, by providing plan review services to prevent flooding, provide adequate drainage, protect and enhance water quality in streams and lakes in Henry County.

Why Henry County Flood Maps Needed Updating

The previous Henry County flood hazard data dated back to 1983 and were seriously out of date. Over the years, drainage patterns have changed dramatically due to land use, surface erosion, and other natural forces. As a result, the likelihood of flooding in some areas has increased significantly. Moreover, the technology used to estimate flooding has been much improved. Up-to-date maps will more accurately represent the risk of flooding; they are an important tool too in the effort to protect lives and properties in Henry County.

Permitting Requirements:

You may also refer to the Henry County Building Department for additional permitting questions, forms, procedures and requirements.

Floodplain Management and the Permitting Frequently Asked Questions

  1. What are the Henry County floodplain requirements?
  2. What is the floodplain permitting process?
  3. How many copies of plans do I need to submit for floodplain review regarding a site development permit?
  4. Does Henry County Stormwater charge a fee to review plans?
  5. What is the purpose of the site plan?
  6. What can I build in the floodway?
  7. What can I build in the floodplain?
  8. Where can I place an Accessory Structure on my residential Property?
  9. What if I have verified the site plan for my project is outside of the Special Flood Hazard Area?
  10. Where Can I find the necessary FEMA FLOODPLAIN FORMS?
  11. Why does Henry County reference two different flood hazard maps?

Unified Land Development Code: Floodplain Management / Flood Damage Protection

  1. Permit Application Requirements.
  2. Floodplain management plan requirements.
  3. Construction stage submittal requirements.


 

Floodplain Management and the Permitting Frequently Asked Questions

What are the Henry County floodplain requirements?

Please review the Henry County Unified Land Development Code (ULDC) Chapter 3 Section 3.00.00 thru 30.01.06

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What is the floodplain permitting process?

STEP 1: You may use the Henry County and FEMA Floodplain Maps to determine if the selected building site has floodplain on the property OR the Henry County Stormwater Management Department will review the flood maps to determine if a site plan is required. View Floodplain Maps.

Is there floodplain on the selected building site?
NO. A site plan is not required.

  1. Complete the Henry County Development Permit Application
  2. Provide a copy of Henry County and FEMA Flood Map. The maps are free and available online.

YES. A detailed site plan is required. Continue to Step 2.

STEP 2: This plan shall include the following items and shall be done by Georgia-registered professional engineer, landscape architect or appropriate registered professional. Site plan drawn to scale, which includes but is not limited to:

  1. All proposed structures, showing spot elevations at building corners, or one (1) foot contour elevations throughout the building site;
  2. Note the proposed lowest floor (including basement and access) elevation on the site plan;
  3. Proposed location of water supply, sanitary sewer and utilities;
  4. Location of drainage and stormwater management facilities (if applicable);
  5. Proposed grading plan, note and delineate any areas and the amount of fill placement or excavation;
  6. Show the boundaries of the base flood elevation and present-future conditions flood elevation (if applicable).

STEP 3: Is any part of the proposed building from step 2 shown inside the floodplain?

YES. A complete floodplain management plan is required as outlined in the Floodplain Management/Flood Damage Prevention (ULDC Chapter 3, Section 3.01.00 thru 3.01.04)

NO. Continue on to Step 4.

STEP 4: Is the lowest floor elevation 3(three) feet above the FEMA base flood elevation (including basement and access) OR 1 (one) foot above Henry County’s present-future? Whichever is higher?
  
YES. Submit the site plan to the Henry County Building Department for review. Please reference the ULDC Floodplain Protection, Section 3.01.04 Provision for Flood Damage Reduction.

NO. Re-draw/design the project to show the lowest floor 3 (three) feet above the base flood elevation OR 1 (one) foot above the Henry County present-future conditions flood plain elevation; whichever is higher. Return to STEP 2.

STEP 5: After construction and prior to the issuance of the Certificate of Occupancy, an as-built elevation certificate must be submitted to the Henry County Building Department.

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How many copies of plans do I need to submit for floodplain review regarding a site development permit?

Residential – 1 complete set is required for Stormwater Management.

Commercial/Multi-Family – 1 complete set is required for Stormwater Management

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Does Henry County Stormwater charge a fee to review plans?

No.

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What is the purpose of the site plan?

Construction of structures in the special flood hazard area (SFHA) can be a health, safety, and environmental hazard. If a special flood hazard area (SFHA) is located on your property, the site plan is used to determine the location of the project in relation to the (SFHA).

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What can I build in the floodway?

Encroachment into the floodway is prohibited, with the exception of projects specified in Section 3.01.03 (E) (2) of the Unified Land Development Code (ULDC)

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What can I build in the floodplain?

Although it is not recommended, any habitable structure can be built in the floodplain, if all requirements in sections 3.01.03 (C), (D), (E), and 3.01.04 of the ULDC are met.

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Where can I place an Accessory Structure on my residential Property?

An accessory structure (e.g. barn, shed, garage, parking lot, or any non-habitable structure) may also be built in the floodplain, provided that it is made of flood-resistant material, able to pass all floodwaters according to Section 3.01.04 (A)(5), and is anchored to prevent collapse, flotation, or lateral movement.

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What if I have verified the site plan for my project is outside of the Special Flood Hazard Area?

For accessory structures, no other review is required by the Stormwater Department. Principle (habitable) structures and substantial improvements, require an elevation certificate (for residential) or flood proofing certificate (for nonresidential) and plan review during construction stage.

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Where Can I find the necessary FEMA FLOODPLAIN FORMS?

For review, guidance and download visit: FEMA Floodplain Management FORMS

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Why does Henry County reference two different flood hazard maps?

FEMA Flood Insurance Rate Map (FIRM), May 2006:
The Federal Emergency Management Agency Maps (FEMA) is used by lenders and insurance companies to determine flood risk.  Not all flood prone areas are mapped on the FIRMs, only the areas studied by FEMA. This map is also known as Digital Flood Insurance Rate Maps (DFIRMs)

Henry County Present and Future Conditions Floodplain Map, May 2010:
The Henry County Present and Future Conditions map is used to determine flood prone areas up to the 100 acres basin and is the principle map used in evaluating development-permitting requirements.

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Unified Land Development Code: Floodplain Management / Flood Damage Protection

Section 3.01.02
A. Permit Application Requirements. No owner, developer or person shall perform any development activities on a site where an area of special flood hazard is located without first meeting the requirements of this section prior to commencing the proposed activity.

Unless specifically excluded by this section, any landowner or developer desiring a permit for a development activity shall submit to the Henry County Development Plan Review Department a permit application on a form provided by the Henry County Building Department for that purpose.

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

B. Floodplain management plan requirements. An application for a development project with any area of special flood hazard located on the site will be required to include a floodplain management/flood damage prevention plan. This plan shall include the following items and shall be done by Georgia-registered professional engineer, landscape architect or appropriate registered professional:

  1. 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 twenty-foot or smaller intervals along the foundation footprint, or one (1) foot contour elevations throughout the building site;

    ULDC 3.01.02 (B) 1 (b) EXAMPLES
    Spot Elevations
    (click image to enlarge)
    Spot Elevations
    One (1) Foot Contour Elevations
    (click image to enlarge)
    Spot Elevations

    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
  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 nonresidential structure will be floodproofed;
    c. Certification that any proposed nonresidential floodproofed structure meets the criteria in subsection 3.01.03.C.2;
    d. For enclosures below the base flood elevation, location and total net area of foundation openings as required in subsection 3.01.03.A.5.
  3. Description of the extent to which any watercourse will be altered or relocated as a result of the proposed development, land disturbance or construction;
  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 applicable state and federal permits necessary for proposed development; and
  6. All appropriate certifications required under this section. 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 director of the building department or designee:

  1. A certified as-built elevation certificate; or
  2. Floodproofing certificate for nonresidential construction including the lowest floor elevation; or floodproofing level, immediately after the lowest floor or floodproofing is completed.

If you require further assistance, you may contact the Henry County Stormwater Management office at 770-288-7246.

 

 

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Last updated: Tuesday February 21 2012

Stormwater Calendar

Stormwater Calendar

Stormwater Survey

Stormwater Calendar

Stormwater Technical & Engineering Documents

Stormwater: Public Outreach

Stormwater: Drainage Complaint


Stormwater - Only Rain Down the Storm Drain

 

Henry County, Georgia - Board of Commissioners - County Government