Sea Grant Helps Communities Prepare for Rising Seas

Levees and other flood control structures provide Louisiana’s coastal communities with one line of defense against tropical storms. With the prospect of sea level rise and other climatic changes by the end of this century, the cities and parishes with a wider array of armaments stand a better chance of combating and mitigating future natural hazards.

A multi-disciplined team from Louisiana Sea Grant is helping local policy makers – beginning with the City of Mandeville, located on the north shore of Lake Pontchartrain – better fortify and prepare their communities.

“Some people on the North Shore and South Shore believe that Hurricane Katrina is the end all be all of storms – that it was a once in a lifetime kind of event. However, models show that it could be much worse under different circumstances,” stressed Melissa Daigle, with LSG’s Law & Policy Program.

One factor that could make the impact of future storms worse is rising seas. A recent study produced by the International Arctic Monitoring and Assess­ment Program concluded that Arctic ice is melting at an accelerated rate. Because of that, sea levels could rise by 35 to 63 inches by 2100. Previous projections were a sea level rise of 7 to 23 inches.

With many of the state’s coastal communities already in low-lying areas, as well as experiencing subsidence, sea level rise puts Louisiana at greater risk.

“St. Tammany Parish was a good place to start our program,” said Daigle “They are already familiar with the threats they face, and they were interested in information about how sea level rise would intensify these hazards.”

Daigle and her teammates conducted a series of workshops during the spring to educate St. Tammany Parish leaders about sea level rise, use of Geographic Information Systems (GIS) data to evaluate storm surge and sea level rise risk, risk perception and communication, and best practices in preparing for future hazards. Also discussed was legal liability of local governments if officials fail to act or act without consideration of pending hazards.

“We had a number of planning sessions with the city and figured out the things they needed most. They needed information, and they really hadn’t considered sea level rise,” Daigle said.

While a long-term plan that takes into account sea level rise and changes in climate is needed for Mandeville’s sustainability and natural hazards resiliency, maintaining the community’s cultural identity is also imperative. “For example, tree canopy is very important to Mandeville,” said Daigle. “We need to preserve the most important things to the community while taking steps to prepare for sea level rise, such as raising houses. A community doesn’t have to lose what makes it unique in order to prepare for hazards such as sea level rise.”

At the end of the project, the city was provided with a toolkit on CD that will help policy makers incorporate what they learned into the development and decision making process.

The planning team is currently working on selecting the next communities it will target.