US Army Corps of Engineers
Baltimore District

Northern Virginia Coastal Storm Risk Management Study

The objective of the Northern Virginia (NOVA) Coastal Storm Risk Management Study (formerly the DC Coastal Study) is to investigate coastal flooding problems, needs and potential solutions for the region. 

This is a $3.5 million study cost-shared evenly between the U.S. Army Corps of Engineers, Baltimore District, and the Metropolitan Washington Council of Governments (MWCOG)
 
The effort is a spin-off of the two-year North Atlantic Coast Comprehensive Study (NACCS) that was completed in January 2015 and was commissioned by Congress as part of Hurricane Sandy recovery. The purpose of NACCS was to help local communities better understand their changing flood risks due to climate change and provide them tools to be better prepared for the future. The DC Metropolitan region, including Northern Virginia, was one of nine high-risk areas identified in NACCS as needing further analysis.  
 

The goal is to reduce coastal flood risk to people, properties, critical infrastructure, services and important resources in the study area, considering future climate and sea level change scenarios. The study authority does not include flood risk from interior (storm drainage) flooding from heavy, localized rainfall, or high tides. However, coastal flooding can be intensified by river flooding. 

Study Area

The authorized study area encompasses more than 57 square miles in the District of Columbia, Maryland and Virginia; however, due to non-federal sponsor funding and interest, the team is focusing on Northern Virginia, to include Arlington County, the City of Alexandria, Fairfax County, northern Prince William County, and the Metropolitan Washington Airport Authority’s Reagan National Airport.                                          

Regional Storm Risk

Flooding is a persistent concern in the Washington, D.C. and Northern Virginia region, including along the Potomac River and its tributaries. 

Problem areas in Northern Virginia include the Potomac River waterfront in Arlington and Alexandria and along Cameron Run and Four Mile Run in Fairfax County, which drain into the Potomac River.

Coastal flooding can endanger lives; prevent access to evacuation routes and critical infrastructure; and cause property and economic damages. 

Vulnerable critical infrastructure within flood zones in the Northern Virginia study area includes the Capital Beltway, George Washington Memorial Parkway, and other roads, highways and bridges; metro rail and stations; passenger and freight railroad services; wastewater treatment plants; water supply systems; stormwater systems; the Reagan National Airport; and national security infrastructure.

Between 1889 and 2006, 18 major flooding events were recorded for Washington, D.C. These were attributed to rainfall and storm surge in both the Potomac and Anacostia river basins. In 2003, Hurricane Isabel caused isolated flooding and wind damage within the study area. The Potomac and Anacostia rivers exceeded flood stage due to the combination of high tides and storm surge. FEMA estimated the damages in Washington, D.C. from Hurricane Isabel to be $125 million. 

Study Objectives

The study team will use existing information and models and leverage past studies to help inform this study and expedite the timeline. 

The study team will: 

1. Assess the refined study area’s problems, opportunities and what the future conditions would be without a project (incorporating climate and sea level change data);

2. Assess the feasibility of implementing system-wide coastal storm risk management solutions such as policy/programmatic strategies, storm surge barriers at selected inlet entrances, or tidal gates at selected lagoon entrances; and

3. Assess the feasibility of implementing site-specific solutions, such as a combination of structural, non-structural, and natural and nature-based features, if system-wide solutions are not possible. Structural solutions include barriers, levees, etc., and non-structural solutions include wet and dry floodproofing, etc. 

The study will provide recommendations to MWCOG to reduce economic damages from coastal flooding to residences, businesses, government offices; and to reduce coastal flooding that disrupts critical infrastructure, services, and shared/interdependent systems within the study area. These shared systems include water, energy and communication utilities; transportation hubs; and federal buildings. The region is only as protected as the weakest link in its shared infrastructure system. This study will help address those critical issues and will aid in the long‐term resilience and sustainability of the region.

Preliminary designs and cost information will be included for the assessments. 

The Corps and coastal communities could seek additional funding to implement the recommendations from this study. Depending on the expertise needed for the recommendations, the Corps or another more suitable agency may lead a project. 

Contact

If you have any information related to flooding or flood risk management that may be relevant to this study, including reports, photos or other digital data, as well as climate change impact analyses or studies, please share this information with the study team by sending an email to MetroDCCoastalStudy@usace.army.mil.   

NOVA Coastal Q&As

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The team will continue to consider ways to engage the public on this study. If you have any information or datasets related to flooding or flood risk management that may be relevant to this study, including reports, photos or other digital data, as well as climate change impact analyses or studies, please share this information with the study team by sending an email to MetroDCCoastalStudy@usace.army.mil.    

In addition, a draft report will be available for public comment. 

The non-federal sponsor, MWCOG, will take the recommendations from the study to decide the best path forward.

Coastal flood risk management recommendations outlined in this study are meant to be customizable to incorporate into local mitigation plans, so jurisdictions outside of the study area can consider all potential options on the table with respect to their budgets.

This study does not lead directly to project construction. The Corps and coastal communities could seek additional funding to start more refined studies or implement the recommendations. The lead agency would depend on the expertise needed based on the recommendations.

The District of Columbia Silver Jackets is an interagency flood risk management team, led by the Army Corps, National Park Service and the District Department of Energy and Environment. It’s a unique team that leverages resources to identify and implement comprehensive and sustainable solutions to reduce flood risks around the District. The team’s priorities include flood inundation mapping and stream gauges; flood emergency planning; interior drainage flooding; levee certification and accreditation; and communication.

For instance, the team created a Flood Inundation Mapping tool, which consists of real-time digital maps housed on the National Weather Service’s web site that display the potential depth and extent of flooding from the Potomac and Anacostia rivers based on impending storms.

The team is also conducting a flood risk management study for vulnerable neighborhoods along Watts Branch. The first part of the study entails modeling the potential flood threat, and the second part entails outlining potential flood risk management options.

The Corps has lead similar studies for the Washington Navy Yard and Joint Base Anacostia-Bolling.

The DC Silver Jackets stress that it is imperative for the public to know their flood risk and take appropriate actions to reduce this risk. Even with projects in place and studies underway, the District is still extremely susceptible to interior flooding caused by storm drains becoming overwhelmed from heavy local rainfall, and there is a large transient population that may not be aware of the flood risks.

The 17th Street closure structure is part of the Potomac Park Levee System. It is situated between the Lincoln Memorial and the Washington Monument, and it reduces risk to human safety and critical infrastructure in downtown District of Columbia from flooding of the Potomac River. The levee system and closure was constructed and is regulated by the Corps of Engineers, and operated and maintained by the National Park Service. Construction of the closure was completed in 2014. The 17th Street closure is a removable structure that can be erected in the event of high water to attach to the floodwalls on both sides of 17th Street and consists of aluminum panels between steel posts.

The Army Corps and other federal partners have been meeting to come up with a plan to address the threat of interior flooding in the Federal Triangle area, and the National Park Service is investigating the use of temporary barriers to be deployed prior to a strong storm to add an extra layer of flood risk management for the District.

There has been extensive work completed related to the vulnerability of individual jurisdictions; however, there is no comprehensive understanding in the region of how a disruption like a large-scale flood event could impact the continuity of operations of agencies or shared infrastructure.

This study will consider past, current, and future coastal storm risk management and resilience planning initiatives and projects by the Army Corps and other federal, state, and local agencies to ensure efforts are not duplicated and that existing projects and studies can be leveraged.