Case Study

Resilient Norfolk Coastal Storm Risk Management

Sector:  Coastal Resilience & Climate Adaptation; Construction
Highlights: Community wellbeing, property protection
Project owner:  City of Norfolk and U.S. Army Corps of Engineers
Project start: ​2016 – Ongoing
Location: Norfolk, Virginia
Community impacted: Urban, Coastal
Hazards mitigated: ​ Coastal flooding, Oceanic events, Hurricanes/Cyclones
Number of vulnerable people made more resilient: ​~244,000
Case study provided by:  City of Norfolk, VA; U.S. Army Corps of Engineers; Norfolk Resilience Partners

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The city of Norfolk, VA, has one of the highest rates of relative sea level rise among Atlantic coastal communities and is increasingly at risk of flooding and damage from coastal storms. The Norfolk Coastal Storm Risk Management (CSRM) Project will reduce the city’s risk from northeasters, hurricanes, and other significant storm events, improving resilience for the cultural and economic heart of the city, its critical infrastructure and over 244,000 people who call Norfolk home.

About the Project

As a result of Hurricane Sandy in October 2012, Congress passed P.L. 113-2, an act to improve and streamline disaster assistance for Hurricane Sandy and other purposes. A portion of this directed actions for the U.S. Army Corps of Engineers (USACE) to take a project-performance evaluation report and comprehensive study to address the flood risks of vulnerable coastal populations in areas affected by Hurricane Sandy within the boundaries of North Atlantic Division, USACE. The North Atlantic Coastal Comprehensive Study identified nine high-risk areas, including the city of Norfolk, warranting an in-depth investigation into the feasibility of federal investment in Coastal Storm Risk Management (CSRM) solutions. The citywide project is divided into five implementation phases:

  1. Downtown: A system of floodwalls with a levee, surge barriers, and natural and nature-based features, extending from Ghent through downtown connecting to the Ohio Creek Watershed project.
  2. Pretty Lake: A system of floodwalls and storm surge barriers to reduce storm surge from entering Pretty Lake at Shore Drive.
  3. Lafayette: A storm surge barrier from Norfolk International Terminal (NIT) to the Lamberts Point area to reduce storm surge risk to the Lafayette River watershed.
  4. Broad Creek: A system of floodwalls, storm surge barriers and tide gates to reduce storm surge from entering Broad Creek at I-264.
  5. Non-structural: A series of property-specific flood mitigation projects: home elevations, basement fills, floodproofing, etc. Work would take place in multiple areas of the city including Berkley, Campostella, Elizabeth Park, Ingleside, Willoughby Spit, Woodbine, and River Forest Shores.

The Norfolk CSRM Study recommended a plan that includes structural, non-structural, Natural and Nature-Based Features (NNBF) to provide comprehensive flood risk reduction for Norfolk.

These NNBF flood mitigation solutions mimic, or restore, natural processes with the aim of wave weakening and storm surge reduction. This includes creating oyster reefs, living shorelines, and wetlands mitigation. NNBF generally require more space than structural measures. In Norfolk, the opportunities to use NNBF are limited by urbanisation and, along the waterfront, the proximity of the federal navigation channel. When used, NNBF must provide the same level of damage reduction as the structural measures included in the plan.

Structural CSRM measures are man-made, constructed measures that counteract coastal flooding issues, including tidal surge barriers and floodwalls/levees. Non-structural elements specifically address individual at-risk properties and focus on reducing the damages from flooding, not preventing flooding. These non-structural features include home elevation, basement fills and commercial floodproofing.

Intended outcomes

Socio-economic

The City of Norfolk’s increased risk of flooding and damage during a coastal storm proves that a resilience strategy is critical to strengthening the coastal community for the future. This project will reduce economic damages from coastal storm risk to businesses, residents and infrastructure and will improve the resiliency of the local economy to impacts from coastal storms. The project will also improve the quality of life for Norfolk residents, workers, and visitors, reduce the risk to human health and safety, and drive economic development opportunities for the city. The project is rooted in social and environmental equity, bringing multiple agencies together with a holistic approach benefitting the entire city and prioritising layers of defence for the most socially vulnerable areas.

Environmental

The $2.6 billion project features storm-surge barriers, nearly eight miles of floodwalls, nearly

one mile of levees, 11 tide gates, and ten pump stations, along with a series of non-structural

projects that include home elevations, basement fills, and commercial floodproofing. Federal requirements mandate that environmental mitigation features are put into place to offset unavoidable wetland and environmental impacts. The Resilient Norfolk project not only adheres to the required mitigation and environmental mandates, but also adds additional NNBFs where feasible and effective, working with the land to reduce flooding risks while minimising impacts. The project navigates the effects of any adverse impacts of construction and use for a multitude of fish, animals, navigation, recreation, air quality and other resources. The project team is advised by and coordinating with many agencies including the U.S. Fish and Wildlife Service, the National Marine Fisheries Service and the Virginia Department of Historic Resources.

How has carbon mitigation been integrated?

The project includes creating oyster reefs, living shorelines, and wetlands mitigation.

Oyster reefs create friction between waves and the sea floor, serving as a natural breakwater, absorbing wave energy before it hits the shore. Oyster reefs can protect underwater vegetation and waterfront communities from some effects of waves, floods, and tides.

A living shoreline is a protected, stabilised coastal edge made of natural materials such as plants, sand, or rock. Living shorelines incorporate plants, rocks, and oysters to naturally stabilise shorelines from erosion, while also maintaining and improving habitat and sustaining coastal resilience.

Wetlands trap and then slowly release rainwater, snowmelt, groundwater, and floodwater. Wetlands act as natural sponges, soaking up and holding water until it can soak into the ground. Riverine wetlands are especially useful in storing and holding flows, including peak flows, which tend to produce flood damage.

 


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