Virginia Beach Sea Level Wise Adaptation Strategy
The City of Virginia Beach, Virginia Sea Level Wise Adaptation Strategy is designed to help guide the city’s steps to become more resilient and adapt to sea level rise and flooding by gradually implementing actions through a watershed-based approach. Virginia Beach consists of four watersheds, both inland and coastal, that are characterized by unique physical properties and land-use patterns and affected by five distinct types of flooding - high tide, wind tide, storm surge, rainfall/compounding, and groundwater flooding. To accommodate these differences, four watershed-specific plans were developed with a suite of adaptation tools and projects for each watershed. The city applied a general “Adaptation Framework” that includes four primary categories of adaptation tools or responses - natural mitigations, engineered defenses, adapted structures, and prepared communities - to address the diverse needs of each of the city’s watersheds. The strategy is the result of a five-year, city-led effort to engage the community and study sea level rise and flooding in Virginia Beach. The strategy is noteworthy for identifying adaptation tools and projects based on the different types of flooding that occur in each of the city’s watersheds. Other local governments may consider this example to similarly craft watershed- or neighborhood-scale adaptation plans in jurisdictions with diverse flooding risks, geographies, and land-use patterns.
Virginia Beach and the Hampton Roads region in Virginia are experiencing the highest rate of sea level rise on the U.S. East Coast, in addition to more frequent and intense precipitation events. The strategy provides that “the area of the [c]ity exposed to coastal flooding will increase by one-and-a-half times in the 2040s, and by two times by the 2070s.”
In response, the City of Virginia Beach developed the Sea Level Wise Program to address present and future sea level rise impacts. It is important to note that the city also initiated a parallel process through a Master Drainage Study to confront the city’s rainfall and stormwater drainage issues. Together, the Sea Level Wise Program and Master Drainage Study will help Virginia Beach to comprehensively mitigate the cumulative, but distinct, impacts of multiple causes of flooding in the region.
The first part of the strategy describes the five distinct types of flooding occurring in Virginia Beach:
- High tide flooding is when flooding occurs at high tide due to rising sea levels.
- Wind tide flooding is when winds blow persistently in one direction for multiple days pushing water into coastal bays and waterways and causing flooding in low-lying areas. Historically, Virginia Beach has not fully understood wind tide flooding due to a lack of water level records. Between 2017 and 2019, Virginia Beach experienced five large-scale wind tide flooding events that led the city to commission two wind-tide-specific studies as part of the Sea Level Wise Program to improve the city’s understanding of wind tide flooding and how to adapt to it (i.e., Numerical Modeling of Wind Tides in Back Bay and North Landing River and The Southerly Wind Frequency Analysis, both appended in the strategy).
- Storm surge flooding is when water rises due to storm winds and events like gales, northeasters, tropical storms, and hurricanes.
- Rainfall (compounding) flooding is when precipitation is experienced at the same time as other types of flooding and precipitation increases or “compounds” flooding impacts by affecting the ability of water to drain.
- Groundwater flooding is when rising sea levels infiltrate freshwater underground aquifers and shift the boundary between saltwater and freshwater inland.
To address the five distinct types of flooding, the strategy proposes a general Adaptation Framework that the city will tailor to the individual characteristics of each watershed. The general Adaptation Framework consists of the following four types of adaptation tools or responses:
- Natural mitigations to preserve environmental assets and increase the use of natural and nature-based features in the city
- Prepared communities to grow educational outreach and promote economic resilience
- Engineered defenses to pursue an expansive defense network
- Adapted structures to regulate new building and development codes and standards, support incentives for flood-resilient design or retrofits, and minimize infrastructure vulnerabilities
In the next part of the strategy, the city applies the general Adaptation Framework to each watershed to accommodate the specific physical, land-use, and flood risk characteristics of each area. The strategy identifies opportunities the city may consider to enhance adaptation and resilience in each one of Virginia Beach’s four watersheds:
- Elizabeth River is the city’s only completely inland watershed. The proposed Adaptation Framework for this watershed focuses on upgrading infrastructure and maintaining use and access to recreational amenities.
- Lynnhaven is the second largest watershed. The proposed Framework focuses on mitigating recurrent flooding impacts, increasing the density of new development in safer, higher ground areas, and protecting low-lying natural habitats that can serve as flood buffers.
- Oceanfront is the smallest, densest, and one of Virginia Beach’s most flood-prone watersheds. Adaptation strategies focus on armoring and creating dunes to protect existing development, which serves as the community’s economic base, while encouraging new development in safer, higher ground areas.
- Southern Rivers is the largest watershed with the largest amount of low-lying land in Virginia Beach. The Framework suggests developing new land-use strategies that can protect natural resources and limit new development in areas prone to flooding.
For each watershed, the strategy discusses impacts facing that watershed and priority adaptation projects the city can evaluate based on the impacts identified. Priority projects are organized according to the four-part Adaptation Framework. The strategy also highlights the anticipated cost, timeline/priority, and benefits of each project. These additional project factors can help the city evaluate potential next steps to implement parts of the strategy.
Going forward, the city will refine the strategy as new information becomes available. The city will also aim to integrate the strategy into other plans and processes - like for hazard mitigation and capital improvement planning and strategic planning and strategic growth area master planning - across city agencies and the Hampton Roads region.
The strategy was the result of a multi-step process to assess sea-level rise and flooding impacts in Virginia Beach and research examples from across the nation to identify the range of tools the city could use to adapt to different flood risks. The strategy was informed by the city and a consultant team that included Georgetown Climate Center.
Publication Date: February 2020
- City of Virginia Beach, Virginia
- Georgetown Climate Center
- Virginia Beach Sea Level Rise Policy Response Report
- City of Virginia Beach - Nature-Based Coastal Flood Mitigation Strategies
- Virginia Beach Public Works Design Standards Manual - Sea Level Rise and Precipitation Adjustments for Stormwater Management Design
- Adaptation plan
- Policy analysis/recommendations