Sediments, Subsidence, and Sea-Level Rise: The Elephant in the Wetlands

By Ivan Gill and Harry Roberts.

Published by The International Journal of Science in Society

Format Price
Article: Print $US10.00
Published online: July 23, 2015 $US5.00

Educational efforts in Louisiana embrace the idea that wetlands are important to coastal Louisiana. A variety of groups have conveyed the message that wetlands, including freshwater swamps and marsh, provide irreplaceable habitat, food sources, and protection from storm surge. Most programs also acknowledge clearly that coastal wetlands in Louisiana are disappearing at alarming rates, threatening cultural, environmental, and economic resources. However, few local educational programs emphasize the fundamental importance of the geological underpinnings of the coastal land loss. The sediments lost from the coastal system by channelization and levee-building are not being replaced at rates sufficient to compensate for subsidence and eustatic sea-level rise. Furthermore, the natural delivery of raw sediments to the deltaic region is a fraction, roughly half, of what it was at the start of the 20th century. With the exception of sediment diversion, all proposed solutions to the land-loss problems fail to address the fundamental nature or scale of Louisiana land loss. The Elephant in the Wetlands is the un-discussed and unmentionable issue: that even if delivery of all the sediment carried by the Mississippi River were to begin today, there would be insufficient resources to stabilize the entire Louisiana coast as we see it today. The implication is that some portions of the coastline would be lost regardless of human effort, and others will be lost if the valuable sediment resources are allocated elsewhere. The political decisions made will be severe: there will be winners and losers, and the political decisions will be controversial and profoundly divisive.

Keywords: Coastal Loss, Sediments, Subsidence, Sea Level Rise, Governmental Response, Louisiana

The International Journal of Science in Society, Volume 7, Issue 3, September 2015, pp.43-55. Article: Print (Spiral Bound). Published online: July 23, 2015 (Article: Electronic (PDF File; 1.093MB)).

Dr. Ivan Gill

Associate Professor, Science Education Coordinator, College of Education and Human Development, University of New Orleans, New Orleans, Louisiana, USA

Dr. Harry Roberts

Boyd Professor Emeritus, Coastal Studies Institute, Baton Rouge, Louisiana, USA