Dr. Robert Twilley on Coastal Erosion
Dr. Robert Twilley spoke to Honors students in West Laville Library Thursday night about the importance of Louisiana’s coast and the national consquences of its loss.
Twilley is the executive director of the LSU-based Louisiana Sea Grant College Program and a professor of oceanography and coastal sciences. He is featured in Mark Hertsgaard’s “Hot: Living Through the Next Fifty Years on Earth,” which is the 2013 Honors College Shared Read book. His presentation, titled “How the Mississippi River Delta Today is an Analogue of a Coastal Future,” was the first installment of the Honors College Fall Research Series.
Twilley said members of Congress see coastal erosion as a state issue, but the coastlines of states like Virginia and Florida will be similar to Louisiana’s in 25 to 30 years.
“They don’t think about the public interest of the nation, which is mind-boggling to me,” Twilley said.
Louisiana is ranked first in the crude oil industry, fourth in the natural gas industry, and has a recreational fishing industry worth $1 billion. The state has the largest wealth of biological resources in the United States. Twilley said if the coastline continues to degrade at its current rate, economic consequences could be dramatic for the country.
“We are connected to a watershed that provides sediment to build our land,” Twilley said. “That land turns around and provides services back to the nation.”
Twilley was referring to the sediment required to form land. The amount of sediment deposited at the end of the Mississippi River is dependent upon the river's momentum. If the river flow does not reach a certain momentum, sediment settles on the river floor and does not form land along the Gulf of Mexico.
Man-made flood control measures have slowed the flow of the Mississippi River, and the sediment supply has been cut in half. Backwater flooding has decreased, but front water flooding has increased, putting communities at risk. The potential annual damage ranges from $7.7 billion to $23.4 billion.
“Land loss by deltaic drowning is neither inevitable nor natural," Twilley said.
The reduction in sediment deposits is not the only issue for Louisianans. Climate change and hurricanes also are a threat to the coast. Twilley said what happens in the Pacific Ocean is connected to what happens in Louisiana’s river delta. The Mississippi River rises when the ocean decreases in temperature. But when the ocean increases in temperature, the river becomes dry, decreasing the river’s momentum.
Scientists project that hurricane intensity and size will increase. Homes on the disappearing coastline will be at a greater risk to hurricane storm surges. Twilley helped to create Louisiana’s restoration plan after Hurricane Katrina. He said a sediment structure along the coast would compensate for the expected 4 mm to 5 mm sea level rise in the next 25 to 50 years.
Twilley also works with the LSU Coastal Sustainability Studio to find solutions for Louisiana’s coast. Located in the Art and Design building, professionals and students use the studio to find engineering solutions for the rising water and shrinking coast. Members study a wide variety of majors, like oceanography, history and social science.
"Organizations like the Coastal Sustainability Studio build a body of knowledge that will get us through the future," Twilley said.
The Research Series continues with Professor Emeritus John Day's presentation titled "Sustainability and Place: How 21st Century Mega-Trends will Affect Sustainability at the Landscape Level" on September 19 at 6:00 p.m. in West Laville Library.
Story by Anna Kalmbach