By Mr. Justin WardMarch 2, 2015
In late 2012, Hurricane Sandy struck and devastated parts of the Northeastern United States, causing more than $50 billion in damage to our communities and infrastructure. The storm's effect on the coastlines was equally devastating, with millions of cubic yards of sand raked away from our coast, making many coastal communities extremely vulnerable to future storms.
In January 2013, the president signed the Disaster Relief Appropriations Act of 2013, authorizing and funding the U.S. Army Corps of Engineers to take steps to reduce that vulnerability through repairing, restoring, and constructing coastal storm risk management projects in the Northeast.
Although a lot of engineering goes into planning, designing, and constructing hard structures such as levees, walls, tidal barriers, and pump stations, engineering is crucial to building and replenishing beaches, as well.
Beaches are important features for coastal storm damage risk management. Bluffs, dunes, berms and offshore sand bars reduce the risk of damage to property and infrastructure by absorbing and dissipating the energy of breaking waves. The Corps' beach projects are designed and engineered to work like a natural beach, allowing sand to shift continuously in response to changing wave action and water levels.
Beach nourishment will reduce but not eliminate risks because storm severity is unpredictable, and can exceed risk reduction design levels. To ensure a beach continues to meet its design criteria and purpose, additional sand must be added periodically to a nourishment project. These nourishment cycles provide opportunities to reevaluate beach performance and sea-level change.
The Army Corps' beachfill projects, authorized and funded after Hurricane Sandy, incorporate the latest science, including sea-level change, future adaptation of hard features, and lessons learned from Hurricane Katrina.
Changing sea levels throughout the Northeast, coupled with improving coastal flood risk analysis technologies can lead to changes in project planning, design, and nourishment.
To address these changes, the Corps has institutional mechanisms in place that allow for adjustments in project dimensions during the life of the project to maintain the design level of coastal storm risk management.
Beachfill projects can account for changes sea levels by adjusting elevations, widths and volumes, based on the best currently available information, explained Jeffrey Wisniewski, a Senior Engineer for the Corps' Sandy Recovery Program.
"Sandy beachfill projects funded by the Disaster Relief Appropriations Bill typically provide for periodic beach renourishment and monitoring over the life of the project," said Wisniewski. "We have the flexibility to make adjustments with regard to the height of that beach berm or dune to take into account the latest available information on sea levels."
The Corps recently completed a report designed to help local communities better understand changing flood risks associated with climate and sea-level change and to provide tools to help those communities to attain improved resiliency by better preparing for future flood risks.
The North Atlantic Coast Comprehensive Study builds on lessons learned from Hurricane Sandy and attempts to bring to bear the latest scientific information planning tools and models available for state, local, and tribal planners, as well as the NACCS Framework and technical products which can be applied throughout the North Atlantic, and to other coastlines in the United States and internationally.
The conclusions of the report, including various coastal storm damage risk management strategies communities can use to adapt to increased flood risk, can be found here: http://www.nad.usace.army.mil/compstudy