EXPLAINER: How wetlands can help buffer Louisiana storms

A multi-billion dollar system of seawalls, levees, pumps and other flood controls helped shield New Orleans from the surge of ocean water swept up by Hurricane Ida. But Ida also encountered natural barriers like wetlands that act as a “speed bump” and blunt the impact of storms.

Although natural defenses have their limits — especially with major events like Ida — experts say they can play an important part in protecting communities and the environment when storms strike.

“There is always a benefit by having these wetlands between you and the storm,” said Gerald Galloway, a recently retired University of Maryland engineering professor who previously worked for the U.S. Army Corps of Engineers.

Since the devastation of hurricanes Katrina and Rita in 2005, a key part of Louisiana's efforts to bulk up its storm defenses has been restoring the wetlands and barrier islands the state has been losing for decades along its coast.

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HOW DOES NATURAL TERRAIN PROTECT AGAINST STORMS?

Wetlands and other natural terrain can act as buffers for wind and water, giving storm surges more to overcome before they reach people and buildings.

“They help with storm protection because they are dissipating energy,” said Hugh J. Roberts, chief operating officer at the Water Institute of the Gulf, an environmental research group.

Roberts compared it to a cyclist riding over rocky debris. Sparse wetlands are like riding over a few pebbles, he said — hardly noticeable. But robust wetlands with elevated terrains are like trying to ride over a long, bumpier stretch of gravel.

The Water Institute has received funding from the Walton Family Foundation, which also supports The Associated Press’ coverage of water and environmental policy.

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