Flood Hazard Information

Last updated Aug. 30, 2017 - 10:37 am

Here's what you need to know about the 23 square miles of floodplain regulated by the Federal Emergency Management Agency (FEMA) and the City of Raleigh.

These areas are subject to flooding during severe storms, like hurricanes or other large rain events that impact the three major river basins in Raleigh (Walnut Creek, Crabtree Creek, and the Neuse River) as well as their tributary streams.

This Q&A will teach about the floodplain and what you need to know about being in the floodplain during severe storms.

View FEMA flood maps to see if your property may be at risk for flooding.

Flood Hazard Mitigation Grant Program

The Stormwater Management Division purchases and restores flood-prone properties that were built prior to the current floodplain development regulations. Turning these areas to green space improves public safety in flood-prone areas, allows the floodplain to function naturally, and in turn reduces flooding. Funding for these projects may come from the City's Stormwater Utility and through FEMA's Hazard Mitigation Grant Program.

In Nov. 2016, the City of Raleigh removed buildings from the Capital Inn property on Capital Boulevard, an area that is within the floodplain and experienced ongoing flooding. Now, as natural green space, this property will see a reduction in flooding and an increase in public safety. This project is part of Raleigh's larger revitalization efforts for Capital Boulevard.

Is your home or business located in the floodplain? Contact the Stormwater Management Division at 919-996-3940 or RaleighStormwater@raleighnc.gov to see if you are eligible to participate in FEMA's Flood Hazard Mitigation Program.

Flood Hazard Areas within the City

  • Areas identified on National Flood Insurance Program (NFIP) Flood Insurance Rate Maps
  • Areas of flood hazard soils shown on the Wake County Soil Survey
  • Areas identified on City of Raleigh drainage basin maps and flood studies

The Stormwater Development Group manages the City's floodplain program by reviewing projects for compliance with NFIP and enforcing City and Federal floodplain regulations during permitting. The City's floodplain regulations are located in Article 9.3 of the City of Raleigh Unified Development Ordinance (UDO).

The Stormwater Development Group also responds to inquiries from citizens, property owners, realtors, lenders, and developers looking for information about weather specific properties are affected by the floodplain. Additionally, the group acts as the local repository for completed Elevation Certificates and all Letters of Map Change issued by FEMA that revise the NFIP Flood Insurance Rate Maps.

Floodplain Development Regulations

Any development in the floodplain within City limits or extraterritorial jurisdiction (ETJ) needs local or state permits. The zoning ordinance, flood ordinance and the North Carolina Building Codes have special provisions regulating construction and other development within floodplains. Without these provisions, flood insurance through the NFIP would not be available to residents in the City of Raleigh.

Any development in the floodplain without a permit is illegal. Non-compliant development within the floodplain can result in the City's probation or possible suspension from the NFIP. This can result in substantially higher rates within the city for purchasers of flood insurance. Therefore, all work proposed within a designated flood hazard area requires a flood permit to ensure compliance with floodplain regulations.

Any reconstruction, rehabilitation, addition or other improvement of a building structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the start of construction of the improvement, over a five (5) year period, must conform to current building and flood regulations, which might involve elevating the entire structure above the Base Flood Elevation (BFE).

More information about obtaining a Flood Permit

Natural Functions of the Floodplain

Floodplains have many positive impacts on the environment.

During large rainfalls, the creeks within Raleigh cannot handle the full volume of flow within the stream banks. The extra volume from these large rainfalls will naturally overflow into the floodplain areas allowing the floodwaters to be stored temporarily, which reduces the impact on residents downstream. For this reason, protecting and managing floodplains is a top priority for the City of Raleigh as it improves the health of Raleigh's creeks and minimizes property damage and loss of life.

Floodplains improve the water quality of Raleigh's streams and creeks through several processes. Stormwater runoff must first flow through the floodplain before entering the creek. As the water flows through this vegetated area, pollutants such as copper and bacteria are filtered into the soil, which removes pollution from the water before entering the stream. Floodplains also allow stormwater to slow down before flowing into the stream, resulting in less stream bank erosion and less sediment in streams (which is a leading pollutant of water quality in the United States).

When streams overtop their banks into the floodplains, unique habitat environments are also formed. For example, after the water recedes back within the stream banks, shallow pools may form within some floodplains, providing habitat for tadpoles, frogs, salamanders, and other aquatic life. Floodplains are ecosystems that survive only through a delicate balance of rising and falling waters. When the floodplains are changed, this balance is altered and the vegetation and wildlife that thrive in the floodplains may no longer be able to survive in the new habitat.

What Causes Flooding in Raleigh?

In many cases, flooding is a natural process. If you live along one of Raleigh's large streams, you have likely experienced some flooding.

Even if you do not live where larger streams are known to overflow the creek banks, you may still experience flooding from small creeks and ditches.

In some cases, stormwater pipes that are undersized, obstructed, or in need of repair also may lead to flooding.

When Does Flooding Usually Occur in Raleigh?

Most of Raleigh's flooding is quick; the water rises and then recedes in a matter of minutes or hours. Flooding usually occurs in Raleigh during heavy thunderstorms in the spring and summer or from slow moving weather systems later in the year.

Can I Get Someone to Visit my Property to Explain Possible Ways to Reduce Potential Flood Damage?

Yes. If you experience flooding at your home or business, contact the Stormwater Management Division at 919-996-3940 or RaleighStormwater@raleighnc.gov to request an inspection. An inspector will meet with you to suggest possible ways to reduce flood damage.

What are Flood Maps?

Flood maps provide flood risk information for a community. Any land area that may be impacted by floodwaters is identified as a floodplain on these maps.

A Flood Insurance Rate Map (FIRM) identifies both the special flood hazard areas and the flood risk premium zones within the community.

Some areas of Raleigh have not been mapped and there are areas that are susceptible to flooding that may not have been identified on FEMA maps.

How Do you Read a Flood Map?

All flood maps contain different flood hazard zone designations that indicate the flooding risk associated with the area. Copies of the FIRM maps available for viewing are located at the Olivia Raney Local History Library.

How do I Determine if I am in a Flood Zone? How can I get a Copy of a Flood Map?

You can contact the Stormwater Management Division at 919-996-3940 or RaleighStormwater@raleighnc.gov and ask to speak to a Stormwater Engineer or access FEMA's Map Service Center and do a "Map Search" for your property. Paper copies of FIRM maps are available for viewing at the Olivia Raney Local History Library.

Where can I Check to see if my Property is in the Regulatory Floodplain?

You can look up your address on the North Carolina Flood Risk Information System.

What are the Basic Construction Requirements in a FEMA-regulated Floodplain?

FEMA-regulated floodplains are within streams whose watersheds are typically larger than one square mile (640 acres). Floodplains of these streams are subject to FEMA regulations.

Local floodplain ordinances require that the lowest floor elevation must be at least two feet above the 100-Year Floodplain Elevation.

FEMA also requires an Elevation Certificate be submitted and approved before electric power can be turned on. This form must be filled out by an engineer, architect, or surveyor registered in the State of North Carolina.

What are the Basic Construction Requirements in a Non-FEMA Regulated Floodplain?

Floodplains of streams in the minor system with watersheds less than one square mile (640 acres) are referred to as City-designated flood-prone areas.

These streams are subject to floodplain regulations contained in the local ordinances.

City of Raleigh ordinances require the building pad in these areas to be at least two feet above the 100-Year Floodplain Elevation or shown by survey to be outside the 100-Year Floodplain + 2 feet limits.

If the building is located within the 100-Year Floodplain + 2 feet limits, a Lowest Floor Certification or physical survey must be used to show the following elevation information:

  • 100+2 feet elevation;
  • Finished floor elevation;
  • Elevation of lowest mechanical equipment;
  • Lowest adjacent grade; and,
  • Lowest elevation on lot.

My House is in the Floodplain. What do I do if I Want to Build an Addition or Otherwise Improve my Home?

Regardless of the extent of your repairs or improvements, you will need building and flood permits before work begins.

Construction activity in the floodplain depends on where the house is located in the floodplain and the cost of the improvement in relation to the value of the house. Any extension of the current footprint may require a variance from the City of Raleigh and possibly FEMA.

If the value of the addition or improvement to the house is less than 50 percent of the market value of the existing structure, you need to only make sure that the improvement meets the floodplain standards.

Additions or other improvements valued at 50 percent or more of the market value of the existing structure are considered substantial improvements. In such cases, the entire structure must be brought into compliance with floodplain regulations.

What Area of the Floodplain is the Floodway Fringe?

Schematic

The floodplain is divided up into two areas, the floodway and the floodway fringe. The floodway is the innermost portion of the floodplain centered on the river/creek. The floodway is the most restricted and encroachments involving fill or structures are not allowed. The floodway fringe is the outer area of the floodplain and is regulated by Raleigh's Stormwater Management Division.

What is the Floodplain Current Regulation?

Only 50 percent of the floodway fringe on your lot can have fill or buildings placed in it.

What Would be Allowed in the Floodway?

Ground level parking, play areas, lawn and garden areas, golf courses, tennis courts, agricultural activities and other private recreational activity that does not impact the ability of the floodway fringe to store water during a flood event.

Besides Increased Flooding, What Other Effects can Result From Developing in the Floodplain?

If you have property in a FEMA floodplain, you may be required to obtain flood insurance along with your regular owner's insurance. These rates can go up due to increased flooding levels within a given community. Also, increased incidences of flooding on your property will have negative impacts on its future resale value.

If I Own a Vacant Residentially Zoned Property, How Will This Impact Me?

If the property is completely in the floodway fringe then you will be restricted from placing any fill or building on that property. If only part of the lot is in the floodway fringe, then fill or buildings may only be placed in the area outside the floodway fringe. If this presents a significant hardship, you may petition the City Council to provide relief from the new ordinance.

If I Own a Residentially Zoned Property With a House on It, How Will This Impact Me?

Any existing fill or buildings present at the time of new ordinance adoption would not be subject to the restriction. You would not be able increase the footprint of the building or add fill that would encroach further into the floodplain.

The only caveat to that is if you were to increase the value of any structure in the floodplain more than 50 percent (either with additions or interior upgrades), then the entire structure would be subject to the regulations, which could require elevating the lowest finished floor of the structure above the floodplain elevation. This requirement is already applicable under the current ordinance.

If I Own a Vacant Commercially Zoned Property, How Will This Impact Me?

If the property is completely in the floodway fringe then you will be restricted from placing any fill or building on that property. If only part of the lot is in the floodway fringe, then fill or buildings may only be placed in the area outside the floodway fringe.

If this presents a significant hardship, you may petition the City Council to provide relief from the new ordinance. There is always the option for commercial buildings to expand in height so as not to increase their impact to the floodplain.

If I Own a Commercially Zoned Property That has Already Been Developed, How Will This Impact Me?

Any existing fill or buildings present at the time of the new ordinance adoption would not be subject to the restriction. You would not be able increase the footprint of the building or add fill that would encroach further into the floodplain.

The only caveat to that is if you were to increase the value of any structure in the floodplain more than 50 percent (either with additions or interior upgrades), then the entire structure would be subject to current regulations. This requirement is already applicable under the current ordinance. Commercial structures have the ability to flood proof or elevate the structure to comply with any new flood elevations since the building was constructed.

What is the Flood Warning System?

Should a severe storm hit the City of Raleigh there is a warning system in place to advise residents of rising water from the floodplain of the Crabtree Creek basin. The City’s 9-1-1 staff contacts residents in the impacted areas when floodwaters rise to dangerous levels. Also, all flood and storm warnings will be broadcasted on all local radio and television stations, including WRAL radio station 101.5 and WRAL television channel 5.

What are Property Protection Measures?

Various alternatives are available to help minimize flooding. If the floor level of your property is lower than the Base Flood Elevation (BFE), consider elevating your structure, if possible. Brochures discussing flood proofing and other mitigation measures are available at the Olivia Raney Local History Library.

The City of Raleigh's Stormwater Management Development Group can provide you with a list of licensed contractors and consultants who are knowledgeable about flood proofing or retrofitting techniques and construction.

If flooding is expected for a specific rain event, some last minute emergency measures can always help. Sandbagging areas where water might enter occupied spaces can protect property. Valuables and furniture may be moved to higher areas of the building to minimize damages. Attaching plywood or other approved protection systems over the windows and patio doors will help protect against high wind damages associated with hurricanes. Whatever emergency protection measures you use, it is always best to have a plan written in advance to make sure you don't forget anything after you hear the flood warning.

To increase the safety of your property and reduce insurance premiums, you should consider building to higher standards. Of course, the most effective and permanent means of protecting your structure is to locate it out of the floodplain. If you are unable to relocate your structure, the next most effective means is to elevate your structure above the base flood elevation. If your house is built since 1989, the City may have a copy of your elevation certificate on file. Please contact the Stormwater Management Division to request a copy.

What is the City of Raleigh Stormwater Utility's Policy About Removing Vegetation Along Streams?

Vegetation along a stream bank is extremely beneficial for the health of the stream. Trees and other plants have an extensive root system that strengthen stream banks and help prevent erosion.

Vegetation that has sprouted up near streams should remain undisturbed unless removing it will significantly reduce a threat of flooding, or further destruction of the stream channel.

North Carolina regulations prohibit the removal of vegetation within 50 feet of all streams in the Raleigh area. These are known as the Neuse River Riparian Buffer Rules and the North Carolina Division of Water Resources should be consulted at 919-791-4200 before any activities are undertaken in these areas.

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