Comprehensive Sea Level Rise


Comprehensive Sea Level Rise and Recurrent Flooding Response Plan​ 

The threat of sea level rise is a very real one, and it’s one that coastal regions like Hampton Roads must face and prepare for.  

      • ​​​​The trend of relative sea level increase is expected to continue and is projected to accelerate through the end of the century. The Virginia Institute of Marine Sciences (VIMS) reviewed SLR projections sourced from U.S. Federal entities to establish planning values for Hampton Roads as an aspect of their Recurrent Flooding Study for the Virginia General Assembly. 
      • The VIMS report recommended a planning scenario of 1.5 feet for the region over the next 20 to 50 years, but notes that 3 feet is possible in the 50-year horizon.  These recommended values are being used in the City’s analysis.  ​
      • The rate of relative sea level rise (SLR) in the Hampton Roads region, is within the top 10 percent of the nation. Long-term records of water levels in southeast Virginia gauges have relative sea level rise trends that are almost twice that of the global average. This is primarily due to the relatively high rate of subsidence in Hampton Roads. 

How does sea level rise affect Virginia Beach?  

      • ​​​ Virginia Beach is a relatively young city, with the majority of development occurring between the 1960s and 1990s. This growth was driven by many families and businesses choosing to call it home and the expanded operations of our military installations. 
      • Sea level has increased by almost 1 foot since the 1960s.​ 
      • ​​Many areas were formerly farmland – development of this with residential and commercial buildings. During rainfall events, much less water is absorbed into the ground because of development.
      • Increased sea level makes it harder for rainfall runoff to drain into the City’s waterways. Water that once entered waterways has to go somewhere – this excess water causes increased flooding. 
      • Flood waters can impact any home at any time – not just waterfront property or affluent communities. ​​​​​​
Regardless of opinions about climate change, the reality is that flooding is increasing and the City must prepare for the future.​

What is the City of Virginia Beach doing?  
      • ​​Beginning in the 2015 budget, City Council provided $3 million in funding for this critical initiative to specifically identify the potential impacts of SLR and develop a comprehensive long-term response plan.  
      • Also, the City received an $844,000 grant - the Regional Coastal Resiliency Grant - awarded by NOAA’s Office for Coastal Management, to further the City’s efforts, bringing the total to $3.8 million. 
      • ​The City has hired Dewberry, a national consulting firm with significant experience in developing strategies for coastal resiliency, to help with planning for reducing our risk.  
      • The study has assessed existing and future flood vulnerability across the City’s four unique watersheds, (Atlantic Ocean, Elizabeth River, Lynnhaven River, and Southern Rivers). The results are being used to identify focus areas for flood risk management. 
      • We are identifying short- and long-term measures that will reduce flooding risks for each watershed.  These will include combinations of policy measures, flood control structures, and structural engineering and nature-based solutions. 
      • The City is updating its stormwater master plan concurrently, creating an opportunity to determine how the increased coastal flood elevations will be reflected through the stormwater system and which causes additional interior flooding.  
      • While the rising waters are a slow-moving problem, they cannot be ignored, so the City is preparing now to address them – 20, 30 and even 50 years out.  
      • The research and flood mitigation strategies developed by Dewberry will be vital to avoid increased flood issues in the future.​ 
      • The Comprehensive City Response Plan in the Lynnhaven watershed is scheduled to be completed in 2018.    The plan for the remaining three major watersheds in the city will be completely shortly thereafter. 
​​​​What can I do as a resident?  ​ ​​​​​
As Dewberry conducts research and looks at the science of flooding in our city, here is what you can do now as a concerned citizen.​ 
      • ​​​Protect your property with the appropriate insurance. 
      • Build responsibly.  
      • Know the degree of your flood hazard. 
      • Do your homework before you purchase real estate. 
      • Share your ideas and concerns with the City. 
      • Help educate your neighbors, co-workers, friends and family about flood protection strategies.​ 
​Also, check out presentations from informational meetings and study reports by clicking on the links to right.

Stormwater Master Planning​

The City of Virginia Beach is currently updating its citywide stormwater master plan, which was first completed in the early 1990’s.  The current drainage plan concentrates on volume of storage and conveyance capacity in the City's four watersheds (Atlantic Ocean, Elizabeth River, Lynnhaven River, and SouthernRivers) which are made up of ​thirty-one (31) drainage basins.  The updated study will model the Primary Stormwater Management System (PSMS).  The PSMS is defined as pipes of 24” diameter or greater, equivalent open conveyance and associated outfalls. PCSWMM, a value-enhanced version of public domain EPA SWMM, is being used for the update.  This update will include a more robust network of secondary storm drainages systems and will include an analysis of BMPs and pollutant loadings. 

As a portion of the update process, staff has populated the City’s GIS inventory to more completely represent the system.  An analysis has been performed to identify missing data shown on the current GIS inventory; data such as pipe size, material, and invert elevation.  This missing data is being delivered in several ways:  using as-built plans, using original approved plans (often with field notes), and performing ground surveys when no record data exists.  The source of the information including the date of the documents, any notation of applicable reference datum, and type of document, is included in the information added to the GIS inventory.  All data is being converted to the North American Vertical Datam (NAVD) 88 datum for input into the models.​

Below is a map of the watersheds in the City of Virginia Beach.  In addition, you can access the completed final reports in the links on the right.

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