How Do Marshes Protect From Storm Surges?
When the tide rises and the storm surge approaches the Louisiana coastline, marshes are our first line of defense against storm surges. Marshes protect our communities from the devastating effects of storm surges because, depending upon the type and category of storm, a robust canopy of trees along with other flora can reduce storm surges anywhere between 5 and 40 percent. The extenuating factors which determine the degree of inland infiltration of the storm surge are: “storm track, speed, duration, size, and associated waves; the regional topography, geometry of the shore, presence of barrier islands, and slope of the ocean bottom; plus the type and thickness of vegetation, and presence or absence of levees,” according to https://www.wunderground.com
. However, if the marsh is subjected to strong sustained winds for extended lengths of time, the storm surge inundates farther into the wetlands and has a devastating impact on our communities.
Sea Levels Will Elevate
Over the course of next century in the Gulf Coast region, sea levels will persistently elevate, coastal land will subside at a constant rate, and the impacts attributable to the shipping industry as well as the oil and gas industry will persist in causing erosion that will subsequently diminish wetland acreage. Currently, the global sea level is increasingly rising at 3 mm per year, and the land mass along the Louisiana Mississippi River delta is diminishing at a rate of 4-11 mm per year. The relative sea level is currently escalating at a rate of 70-140 cm (2.3 – 4.6 feet) per century. Although it is debatable, global warming may increase the relative sea level even more. Wetlands are disappearing at an average rate of more than 23 square miles (60 square km) per year, and that rate increases during volatile hurricane seasons. Across recently lost wetlands, the water level has increased to 1 meter deep and up to two meters deep in previously lost wetlands. Why is this of great concern? This is of great concern because: