Flood Management

• Introduction to Flood Management in Prince George's County
• Local Flood Hazards, Mapping, and History of Flooding
• FEMA Website
• Flood Insurance Rate Maps and Flood Insurance (NFIP, CRS, CTC, FIRMs, LOMA/LOMR)
• FEMA Floodplain Map of Prince George's County
• Elevation Certificates
• Known Floodprone Structures
• Flood Warning Systems
• Countywide Flood Damage Reduction Strategies
• Property Protection Projects (retrofitting, drainage, protecting against high wind, etc.), and Substantial Improvement/Damage
• Permitting
• GIS and Mapping Components
• Watershed Studies
• Drainage Maintenance
• Public Outreach
• Floodplain Directory of Information Services
• Hurricane Season Special Warnings
• Disaster Do’s and Don’ts
• Disasters - Prepare & Plan
• Frequently Asked Questions (FAQs)

Introduction to Flood Management in Prince George's County

A floodplain is an integral part of the stream system. It provides storage capacity for high flows, helps reduce the erosive power of the stream during a flood, reduces the discharge of sediment during high flow periods and helps flood waters to move downstream. Floodplains also offer opportunities for wildlife habitat which can increase the biotic diversity of a stream. The 100-year floodplain is that land area adjoining the stream that has a 1% or greater probability of flooding in any given year. Floodplains provide a stream with buffer and water quality benefits as well.

It is the policy of the Prince George's County Government to preserve the 100-year floodplain as part of the natural system of a stream, and to further preserve it in a natural state in order to provide adequate storage for flood waters and sufficient carrying capacity to safely move flood waters downstream. Where existing structures in the 100-year floodplain cannot be protected in an environmentally sensitive and cost effective manner, the County may offer to acquire them to reduce the potential for property damage and eliminate potential obstruction of flood water. Future development is not permitted within the ultimate 100-year floodplain. Prince George's County has used ultimate conditions hydrology to determine flood discharges and to map areas of the County experiencing rapid urban and suburban growth. Ultimate conditions hydrology and mapping uses projected land-use conditions based on a community's zoning maps and/or comprehensive land-use plans in determining flood discharges, flood elevations, and corresponding areas at risk.

Prince George's County has, through the Maryland-National Capital Park and Planning Commission, established a policy to acquire stream valley parks throughout the County. Stream valley park acquisition permits public ownership of the floodplain, thus eliminating pressure for private development and providing recreational opportunities. Stream valley parks will continue to be an important component of the County's recreation, open space and flood management programs.

Flood Management for Prince George's County is guided by the following goals:

• Reduce or eliminate existing flood hazards;
• Prevent future flood hazards from developing;
• Reduce the economic losses associated with flooding events;
• Provide for expanded recreational and aesthetic opportunities in the County;
• Restore, preserve and enhance environmental quality wherever possible; and
• Improve the quality of life in Prince George's County.

The Floodplain Management Ordinance was adopted by the County Council in April of 1989 and amended in 1993 to conform with State and Federal requirements. The ordinance replaced those portions of the County Code that dealt with floodplain management. The previous code provisions have been deleted. The new ordinance is modeled after an ordinance suggested by the Maryland Department of the Environment (MDE). The Federal Emergency Management Agency (FEMA) contracted with MDE to review local floodplain ordinances and assure that they met FEMA requirements for eligibility for flood insurance.

The ordinance prohibits filling or construction in the floodplain generally, but allows for a variance under certain circumstances, for example, to meet an important public need. Where filling is needed within the floodplain, an equal volume of compensatory storage must be provided. Furthermore, an impact study is needed to ensure that the floodplain elevation will not be increased. Revisions have been made to other sections of the Code, such as the Subdivision Ordinance, to bring them into conformance. The ordinance also contains requirements for the protection of buffers, wetlands and other natural features associated with the floodplain.

Prince George's County has been participating in FEMA's National Flood Insurance Program (NFIP) since 1972. The current effective Flood Insurance Rate Map (FIRM) can be reached by clicking on the FEMA Floodplain Map of Prince George's County link.

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Local Flood Hazards, Mapping, and History of Flooding

All waterways and bodies of water are subject to flooding – a condition that occurs when the volume of water exceeds the capacity of the waterway channels or when tidal waters are pushed inland by coastal storms:

• Riverine or nontidal bodies of water are those that drain upland areas and are not influenced by coastal and tidal processes. In addition to rivers, nontidal bodies of water include streams and creeks and other small flowing waters. Flooding can also occur in localized low spots, even if the area is not adjacent to a body of water.

• Coastal flooding affects tidal bodies of water, including the tidal reaches of the Potomac River and the Patuxent River in Prince George’s County. The Potomac River is subject to tidal flooding along its entire length in the County, and the Patuxent River is subject to tidal flooding up to the confluence of Western Branch.

The Prince George’s County Department of Environmental Resources recognizes and manages riverine flood hazard areas that are designated in two ways:

• Areas identified as vulnerable to flooding from the 1% annual chance flood (100-year floodplain) that are shown on the County’s Flood Insurance Rate Maps (FIRMs) prepared by FEMAs National Flood Insurance Program (NFIP); and

• Other flood maps based on studies prepared by the County to evaluate the impact of future development. These maps often include areas not studied by the NFIP.

The first Flood Insurance Study and Flood Insurance Rate Maps (FIRMs) for the County were dated August 4, 1972 and prepared by the U.S. Department of Housing and Urban Development (a precursor agency to FEMA). Since that time, updates to several panels have been completed. The most recently revised and reprinted map panels are dated September 6, 1996.

Starting in the 1980s, the Department of Environmental Resources began to obtain State grants and use County funding to prepare more up-to-date watershed studies to delineate floodplains. The County’s studies and maps, prepared with detailed base map data and detailed engineering models, account for future watershed development. They also are the basis for the State’s regulation of nontidal waterways. Watershed studies have been prepared for the following bodies of water:

• Piscataway Creek (adopted July 1986);
• Henson Creek (adopted July 1986);
• Western Branch of the Patuxent River (adopted July 1983);
• Tinkers Creek (adopted September 1980);
• Anacostia River;
• Folly Branch;
• Collington Branch;
• Bald Hill Branch;
• Southwest Branch;
• Charles Branch;
• Oxon Run; and
• Beaverdam Creek.

The figure below shows the extent of flooding as depicted on the latest FEMA Flood Insurance Rate Maps. For more information on FEMA Flood Insurance Rate Maps, how to locate your property on a FIRM, a description of the flood zones, and information on amendments or revisions to the FIRM, visit the section titled “Flood Insurance Rate Maps and Flood Insurance.”

 Flood Hazard History in Prince George’s County

Prince George’s County has experienced some riverine and stream flooding in recent decades, although sound management of flood hazard areas and construction of flood control projects has reduced potential losses. Notable riverine and coastal flooding has occurred several times since 1933.

• August 1933 – This unnamed hurricane caused flooding along the Potomac River and throughout the Chesapeake Bay; the Livingston Bridge on Piscataway Creek also flooded.
• October 1954 – Hurricane Hazel raised water levels in the Potomac River Basin; statewide, the storm caused 6 deaths and an estimated $11.5 million in damage.
• August 1955 – Hurricane Connie caused riverine flooding that inundated a large commercial section of Upper Marlboro and flooded several buildings along Piscataway Creek; surge reached 4 feet above normal at the confluence of Patuxent River with Western Branch.
• August 1971 – Heavy rain and flooding.
• June 1972 – Tropical Storm Agnes; this storm of record brought high water levels along the Patuxent and Potomac River basins; statewide, it caused 19 deaths and $80 million in damage; in Prince George’s County, the storm caused more than $10 million in damage (see box).
• September 1975 – Hurricane Eloise; heavy rain and flooding; Prince George’s County was included in the major disaster declaration.
• September 1978 – Hurricane David; Prince George’s County was included in the major disaster declaration.
• November 1985 – Hurricane Juan affected the Potomac River Basin; Prince George’s County was included in the major disaster declaration.
• September 1996 – Hurricane Fran; remnants of this large storm caused flooding along the Potomac River Basin; Prince George’s County was included in the major disaster declaration.
• September 2003 – Hurricane Isabel produced widespread wind damage, power outage, and localized flooding.
• June 2006 – Heavy rain and flooding.

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Flood Insurance Rate Maps and Flood Insurance (NFIP, CRS, CTC, FIRMs, LOMA/LOMR)

• National Flood Insurance Program (NFIP) Information
• Community Rating System (CRS)
• Cooperating Technical Community (CTC) Program
• Is your property in a flood hazard area?
• Flood Insurance Rate Maps (FIRMs)
• Letters of Map Amendment and Revision (LOMA/LOMR)
• Elevation Certificates
• Known Floodprone Structures

National Flood Insurance Program (NFIP) Information

In 1968, Congress created the National Flood Insurance Program (NFIP) in response to the rising cost of taxpayer-funded disaster relief for flood victims, and the increasing amount of damage caused by floods. The NFIP makes Federally-backed flood insurance available in communities that agree to adopt and enforce floodplain management ordinances to reduce future flood damage. National Flood Insurance is available in more than 20,000 communities across the United States and its territories.

The NFIP is managed by the Federal Emergency Management Agency's  Federal Insurance Administration  and Mitigation Directorate. The Federal Insurance Administration manages the insurance component of the NFIP, and works closely with FEMA's Mitigation Directorate, which oversees the floodplain management aspect of the program.

The NFIP, through partnerships with communities, the insurance industry, and the lending industry, helps reduce flood damage by nearly $800 million a year. Further, buildings constructed in compliance with NFIP building standards suffer 77 percent less damage annually than those not built in compliance. Every $3 paid in flood insurance claims saves $1 in disaster assistance payments.

The NFIP is self-supporting for the average historical loss year, which means that operating expenses and flood insurance claims are not paid for by the taxpayer, but through premiums collected as flood insurance policies. For more information on NFIP, visit the FEMA website at www.fema.gov/nfip.

Top 10 Facts Everyone Should Know About the National Flood Insurance Program

•  Everyone lives in a flood zone.
•  Flood damage is not covered by homeowners insurance policies.
•  You can buy flood insurance no matter what your flood risk.
•  There is a low-cost policy for homes in low to moderate risk areas.
•  Flood insurance is affordable.
•  Flood insurance is easy to get.
•  Contents coverage is separate, so renters can insure their belongings too.
•  Up to a total of $1 million of flood insurance coverage is available for non-residential buildings and contents.
•  There is usually a 30-day waiting period before the coverage goes into effect.
•  Federal disaster assistance is not the answer.

1. Everyone lives in a flood zone.

•  You don't need to live near water to be flooded.
•  Floods are caused by storms, melting snow, hurricanes, and water backup due to inadequate or overloaded drainage systems, dam or levee failure, etc.

2. Flood damage is not covered by homeowners policies.

•  You can protect your home, business, and belongings with flood insurance from the National Flood Insurance Program.
•  You can insure your home with flood insurance for up to $250,000 for the building and $100,000 for your contents.

3. You can buy flood insurance no matter what your flood risk.

•  Whether your flood risk is high, medium, or low, you can buy flood insurance as long as your community participates in the National Flood Insurance Program.
•  It's a good idea to buy, even in low or moderate risk areas: approximately 25 percent of all flood insurance claims come from low to moderate risk areas.

4. There is a low-cost policy for homes in low to moderate risk areas.

•  The Preferred Risk Policy is available for just over $100 a year.
•  You can buy up to $250,000 of coverage for your home and $60,000 of coverage for your contents.

5. Flood insurance is affordable.

•  The average flood insurance policy costs a little more than $300 a year for about $100,000 of coverage.
•  In comparison, a disaster home loan can cost you more than $300 a month for $50,000 over 20 years.

6. Flood insurance is easy to get.

•  You can buy NFIP flood insurance from private insurance companies and agents; call yours today!
•  You may be able to purchase flood insurance with a credit card.

7. Contents coverage is separate, so renters can insure their belongings too.

•  Up to $100,000 contents coverage is available for homeowners and renters.
•  Whether you rent or own your home or business, make sure to ask your insurance agent about contents coverage. It is not automatically included with the building coverage.

8. Up to a total of $1 million of flood insurance coverage is available for non-residential buildings and contents.

•  Up to $500,000 of coverage is available for non-residential buildings.
•  Up to $500,000 of coverage is available for the contents of non-residential buildings.

9. There is usually a 30-day waiting period before the coverage goes into effect.

•  Plan ahead. Don't be caught without flood insurance when a flood threatens your home or business.

10. Federal disaster assistance is not the answer.

•  Federal disaster assistance is available only if the President declares a disaster.
•  More than 90 percent of all disasters in the United States are not Presidentially declared.
•  Flood insurance pays even if a disaster is not declared.

Source: FEMA: NFIP

Community Rating System (CRS)

The Community Rating System (CRS) is a program started in 1990 under the NFIP. The program was designed to recognize and encourage community floodplain management activities that exceed the minimum NFIP standards. Under the CRS, flood insurance premium rates are adjusted to reflect the reduced flood risk resulting from community activities that meet the three goals of the CRS: (1) reduce flood losses; (2) facilitate accurate insurance rating; and (3) promote awareness of flood insurance.

There are ten CRS classes: class 1 requires the most credit points and gives the largest premium reduction, while class 10 is the entry level into the CRS and carries no premium reduction. Prince George's County is currently rated Class 5 under the CRS, which translates to a 25% reduction in flood insurance rates for local residents and businesses. The Class 5 rating places Prince George's County in the top 2% of over 1000 communities nationwide that participate in the CRS. For more information on the CRS, visit the FEMA web site at http://www.fema.gov/business/nfip/.

The Cooperating Technical Community (CTC) Activities in the County

With GIS-based H&H models, the County has received grant funding from FEMA under two separate programs to automate the floodplain information in the County: the Cooperative Digital Flood Mapping Program and the Cooperating Technical Community (CTC) Program. Under the CTC Program, the County is proposing to conduct several additional activities using these GIS models. Specifically, these activities are:

• Completed a countywide GIS-based 2-ft topography using the newly developed technology such as LIDAR (total cost is approximately $400,000). FEMA, the Maryland State Highway Administration, the Maryland-National Capital Park & Planning Commission and the County have already agreed on cost-sharing;
• Re-do the entire FEMA study (normally referred to as the Flood Insurance Study) using our GIS-based hydrologic and hydraulic (H&H) models. The total cost will be approximately $250,000. This cost includes the new FEMA floodplain mapping in digital form. To date, the County has submitted to FEMA the following Watershed Studies: Western Branch; Charles Branch; Anacostia River; Henson Creek; Piscataway Creek; and Patuxent River mainstem;
• The County will conduct a technical review of all FEMA map amendment (LOMA) and map revision (LOMR) requests and then update the changes. The County will charge the developer a review fee that is same as the fee schedule currently employed by FEMA;
• The County will continue to conduct floodplain studies for developers using our GIS-based H&H models. The results of the studies will be incorporated into the LOMA or LOMR process (the County will charge approximately $3,000 for each study);
• The County has converted the GIS-based H&H models (WMS-Watershed Modeling System) into a more user friendly environment such as ARC-VIEW to allow any jurisdictions that have standard PCs to easily utilize these models. The cost for this conversion was approximately $100,000; With this new floodplain database, the County will provide floodplain inquiry services to homeowners, insurance companies, and lending institutions for a minimal fee. The County is in the process of converting the new GIS-based models; and
  
• The County will conduct a detailed Damage Assessment Analysis after a flood event using this GIS-based H&H models. FEMA will need to provide the County with the necessary training.

Is Your Property in a Flood Hazard Area?
Special Flood Hazard Areas are areas located within the 100-year floodplain, defined as any area that has a one percent chance of flooding in any given year. Smaller scale floods (50-year and 10-year) have a greater chance of occurring in any given year and can also pose a significant flood hazard to persons and property in close proximity to channels and streams. Additionally, floods larger than the mapped 100-year event can occur.

First and foremost, you should become informed as to the flood hazard potential on your property. The Prince George’s County Department of Public Works and Transportation will review floodplain information and studies available in their files to determine the location of your property with respect to the floodplain as established in the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps. You may contact the Prince George’s County Department of Public Works and Transportation at (301) 883-5777 for assistance with this information.

Any information provided by the County does not constitute an assurance or representation that flooding may or may not occur on your property during any given event, but should assist you as a general matter in determining the need for flood insurance by assessing the extent of flooding potential on your property.

Flood Insurance Rate Maps (FIRMs)

The FEMA Flood Insurance Rate Maps (FIRMS) are the official maps showing the community’s Special Flood Hazard Areas . These maps are utilized as the basis for local floodplain management regulations and mitigation efforts, to assess flood risk, and to determine if flood insurance is required for structure(s) on a property. Although these maps are not property specific (e.g. no lot boundaries), by using the major roads and flooding sources for reference, users can get an idea of the flood risks in their area. These maps are available to view online at the Map Service Center ( msc.fema.gov ) or at the Prince George’s County Department of Environmental Resources' offices in Largo, Maryland. Additionally, the Map Service Center site has an address search feature that allows a user to find the correct FIRM panel using their address in an on-line search tool.

For additional assistance with using the FIRMs, please contact the FEMA Map Assistance Center at 1-877-FEMA MAP, visit the following website ( www.fema.gov/hazard/map/firm.shtm ) , or contact Yanping Zhang at (301)883-5787 or (301)883-3311

Letters of Map Amendment and Revision (LOMA/LOMR)

In some cases, a lender determines that a property is in the Special Flood Hazard Area (SFHA), or 100-year floodplain, and requires the owner to purchase flood insurance. If the property owner wishes to dispute the fact that they are in the SFHA, they can apply for a Letter of Map Amendment (LOMA) or a Letter of Map Revision Based on Fill (LOMR-F), if fill placement is the basis of the request.

Forms for this application process may be found on FEMA’s website at www.fema.gov/plan/prevent/fhm/frm_form.shtm .

You may also access tutorials designed to assist in the preparation of these forms at www.fema.gov/plan/prevent/fhm/ot_main.shtm . This tutorial will guide you through the application and provide tips on filling out the forms.

Upon receiving a completed application, FEMA reviews property-specific information and makes a final flood zone determination for the property. Once an application is received with all the required supporting data, the LOMA or LOMR-F is normally issued within 60 days. If the LOMA or LOMR-F removes the SFHA designation from the property, it can then be presented to the lender as proof that there is no Federal flood insurance requirement for the property. Bear in mind that even though a LOMA or LOMR-F may remove the Federal requirement for flood insurance, a lender retains the prerogative to require flood insurance.

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Elevation Certificates

Elevation certificates are prepared by surveyors and document the ground elevation, floor elevation, and general building characteristics for a structure. The County has approximately 763 elevation certificates on file electronically and available to the public. Property owners may use the certificates for flood insurance rating purposes, and the County uses the detailed information to evaluate mitigation options. Elevation certificates are available for the structures listed in the following table. For more information on elevation certificates please call Mike Colgan  at (301)883-5944 or (301)883-3311.

Links to Elevations Certificate (PDFs)

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Known Floodprone Structures

• Addresses for Floodprone Structures

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Flood Warning Systems

Flood Warning System at Western Branch

The Western Branch Comprehensive Watershed Management Plan was prepared by the Prince George's County Stormwater Management Technical Group in 1981. Even though the US Army Corps of Engineers had constructed a floodway through Upper Marlboro to carry flood waters away, there are 73 commercial structures, 33 residential structures, and 39 garages/sheds subject to flooding in the Upper Marlboro Area. To date, no additional flood control devices have been proposed or planned to mitigate these known flooding hazards. A consulting engineering firm, Engineering Technology Associates (ETA), has completed a hydrologic and hydraulic analysis or watershed study of Western Branch. This study was not designed to produce or evaluate possible solutions that will minimize flooding problems in the Upper Marlboro area. Rather, this study was meant to determine the flood levels in the Western Branch at Upper Marlboro. This analysis will form the technical basis to be used by the County to select and evaluate possible solutions to the flooding problems in the Watershed. Until the final study and selection of alternatives is completed and ready for implementation, it would be prudent to have an interim program for limiting the extent of flood damage that may occur. Such an interim program to limit flood damage has been proposed in the form of a flood warning system. The Flood Warning System would provide for the monitoring of rainfall and stream flow data to determine if a flood is imminent. The Flood Alerting System will allow the County to use the information gained with the Flood Warning System to alert those in danger that the danger exists.

Preliminary analysis of how the flood warning system would work indicates that Upper Marlboro could reasonably expect ten hours of warning before a flood. Inasmuch as the there are several auto dealerships in and near the 100-year floodplain on Maryland Route 301 in Upper Marlboro, many hundreds of thousands of dollars in flood damage could be avoided simply by moving the cars out of danger.

When completed, the flood warning system will be integrated into the County's Emergency Management System. In this way, when flood waters begin to rise, County public safety officials who use the Emergency Management System will have information as soon as it becomes available and will have a comprehensive understanding of the status of the flood.

The U.S. Army Corps of Engineers has completed a study of the efficacy and desirability of installing a flood warning system in Western Branch. The study indicated that such a flood warning system is feasible and desirable. The flood warning and alerting system for the Western Branch has been designed and partially implemented and may be a model for other watersheds within the County. The flood warning and alerting system will continue to provide an additional margin of safety and will be retained as a permanent feature of the Western Branch Flood Management System.

Prince George’s County has received state grant funding for the upgrade of the Western Branch Flood Warning System. It will be in full operation June 1, 2008 and may be viewed online at http://www.afws.net/data/md/Prince_Georges.htm

Flood Warning System near/at City of Laurel

Due to severe and frequent flooding problems occurring in low lying areas of the City of Laurel and areas such as Woodland Grove Apartments (immediately outside the City limits), a separate flood plan was developed for this area. The plan included the services of the Community Alerting Network to provide telephone notification to impacted residents and businesses. This system has been implemented through the cooperative efforts of the Washington Suburban Sanitary Commission (WSSC), the City of Laurel and the Office of Emergency Management.

Flood Warning System at Anacostia River

According to a preliminary Anacostia River Watershed Study prepared by Greenhorne and O'Mara, Inc. in 1994, more than 3,000 structures may be floodprone within the Prince George's County portion of the Anacostia Watershed. So far, no effective flood control measures have been proposed to mitigate these flooding hazards. Given the fiscal constraints of flood management in the Anacostia, a flood warning system is a cost effective flood hazard mitigation measure. The County is working with the U. S. Army Corps of Engineers to develop the flood warning system for this watershed. The flood warning system at Anacostia River is now in full operation and may be viewed online at http://www.afws.net/data/md/Prince_Georges.htm .

Wide Area Rapid Notification (WARN)

Prince George’s County residents will receive immediate notification of emergencies through a new state-of-the art communications system operated by the County’s Office of Homeland Security. This is possible with the Wide Area Rapid Network (WARN) system.
 
The computerized system allows County public safety agencies to transmit a wide range of public safety information messages rapidly and instantly to residents. WARN goes beyond traditional systems to instantly communicate with as many as 10,000 residents per minute. The internal system intuitively converts text messages to voice, allowing notification to multiple devices, including phone lines and text messaging devices.
 
The residents of Prince George’s County are now only a phone call away when they need to get important information into their hands. WARN allows the Office of Homeland Security to keep in touch during localized or countywide emergencies. The ability to alert communities instantly and get County personnel into action fast can make a critical difference in public safety.

  WARN at a glance:

• WARN is a suite of emergency products for Communications and Information Continuity, offering command and control by and between government, public safety agencies and other vital public and private sector groups. The system can provide notification of Homeland Security and health emergencies, hazardous material/chemical spills, accidents, fires, and floods. The system can be used for meeting announcements, the status of government, treatment and vaccination coordination efforts, and general alerts.
• WARN Broadcast (Public) allows instant and pinpointed public notification to all citizens using a predetermined grid or mapped database for a geographic area. The system allows instant calling for a wide range of public informational and safety purposes.
• WARN Command is a more specialized version of WARN and is used by public safety command and control centers for business continuity. The system, which includes all of the power of WARN Broadcast plus communication escalations, connects to every voice and text device and facilitates message cascading and call bridging.
• WARN Geographical Information System uses geographical maps to issue instant notifications to the public based on geographic location.

In the event of a major flood or other flood-related hazard, individuals registered in the system are notified via phone, fax, e-mail, or pager. If you would like to be added to our database, please fill in the form below. You may include more than one contact number or e-mail address. If you decide to add your contact numbers to our database, please provide us with your name and address so that we can associate your number with your address.

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Countywide Flood Damage Reduction Strategies

Flood Study Findings

The multi-agency Stormwater Management Technical Group has completed a fifteen-year study effort to define the extent of the major flooding problems in the County. The study shows that approximately 4,000 structures are flood prone in a 100-year storm event. Much of the flooding is concentrated in the older, highly-urbanized inner beltway communities targeted for revitalization.

Countywide Comprehensive Flood Dama