Coastal Land Loss in Louisiana: From Denial to Reality
The coastline formed by the Mississippi River is changing continually as part of the never-ending interplay between the forces and processes reshaping and realigning coastal contours and bathymetry. Over millennia, this formative process created Louisiana’s expansive wetlands that once encompassed 7.3 million acres (11,500 square miles) – about the size of Connecticut and Delaware combined – and accounted for at least 40 percent of the nation’s marsh/swamp ecosystems. This natural land-building process, however, has been disrupted by human activities in recent decades—with catastrophic results. Deprived of essential sediments, Louisiana’s coastal wetlands are subsiding and eroding at an alarming pace that casts into doubt humanity’s ability to inhabit and exploit one of the planet’s most economically productive regions.
Erosion alone claims an area the size of a football field every hour, as canals, subsidence, muskrat and nutria eat-outs, salt water intrusion, cold fronts, sea-level rise, and change in the regional hydrology collectively take their toll on this productive habitat. These forces have transformed the state’s once pristine coastal “trembling prairie” into a tattered, shrinking geomorphic artifact. To put this land loss into perspective, Louisiana loses an area greater than New Orleans (180.6 square miles) every 7.2 years.
Alarmed by the disappearance of these wetlands, many concerned citizens now believe that unless corrective measures are initiated soon, the damage to the coastline’s fragile ecosystems will be irreversible. Further, wind and waves are causing the state’s barrier islands to move landward at rates up to 65 feet per year. Between 1900 and 2000, some islands lost nearly half of their surface area; others are completely gone. The region is losing more than a productive estuarine/wetland habitat; the citizens are losing a natural buffer against the full force of a hurricane-induced storm surge. Katrina, for example, generated a surge that approached 30 feet, which is about the height of a three-story building.
Louisiana’s scientific community has diligently investigated and reported the state’s escalating coastal land-loss problem for more than a half-century; yet, coastal erosion has been an urgent political topic only since the first decade of the 21st century. Prior to that time, most policy-makers simply ignored the problem or denied that it even existed. Amazingly, those most affected, the residents of local sea-level communities, simply did not—and, according to a recent Yale University study, still do not—believe their land is washing away. Through their willful blindness, the deniers also generally ignore the impact of increasingly severe natural and manmade catastrophes that repeatedly pummel their environmentally beleaguered homeland: Hurricanes Isadore (2002), Lili (2002), Cindy (2005), Katrina (2005), Rita (2005), Gustav (2008), Ike (2008), Isaac (2012), Harvey (2017), the Macondo/Deepwater Horizon oil spill (2010), the Mississippi River’s “high water” episodes of 2008, 2011, and 2016, and repeated “100-year” rain events, which, in 2016 alone, damaged approximately 146,000 homes in the Louisiana coastal plain.
The once-pervasive notion that Louisiana’s wetlands were too big to fail was — and remains — a widespread misconception. Unfortunately, the ecosystems obscured the darkening reality until an accident of history changed this belief. In the 1960s, President Lyndon Johnson wanted to know if it were possible to divert Mississippi River water to West Texas. The U.S. Army Corps of Engineers issued LSU a feasibility study contract. After investigatory analysis, the research team, under the direction of Dr. Sherwood Gagliano, discovered the Pelican State was losing about 17 square miles of land a year – a number that has fluctuated through time, rising, according to one estimate, to 35 square miles. As a result, the science was clear; diverting the Mississippi would exacerbate the erosion problem dramatically, and the river was not diverted.
Once completed and carefully peer-reviewed, this groundbreaking study was put on a shelf, where it remained largely ignored until later research proved its prescient significance. Beginning in the 1970s and accelerating after 2000, dramatic improvements in computer-aided cartography, GIS, repetitive satellite imagery, photo interpretation and surveying technology, three-dimension models and computer simulations provides better, more accurate measurements of land loss. The 1970 LSU research findings were further reinforced by Dr. Karen Wicker’s 1980 study Environmental Characterization of Terrebonne Parish: 1955-1978, which was one of the first comprehensive land loss assessments of individual coastal parishes. That study morphed into the Atlas of Shoreline Changes in Louisiana from 1853 to 1989, which, in conjunction with a burgeoning number of applied research endeavors, more thoroughly documented Louisiana’s coastal lowlands issues that increasingly endangered the lives and livelihoods of residents supported by wetland resources.
Louisiana has emerged as the national poster child for the dangers environmental changes pose to vulnerable coastal communities. The state’s collective responses to these unprecedented challenges should consequently serve as a national template for addressing environmental Armageddon. The nation must also come to terms with the wetland loss crisis, which until recently was not recognized as a national priority. Recognition at all levels of government was a slow process. In 1990, Louisiana legislators convinced Congress to enact the Coastal Wetlands Planning, Protection and Restoration Act (popularly known at the Breaux Act), which allowed federal funding to go toward wetland protection. Thirty-five years after the initial 1970 study – Louisiana restructured the State’s Wetland Conservation and Restoration Authority to form the Coastal Protection and Restoration Authority (CPRA), the central hub to articulate and development a comprehensive coastal protection plan for Louisiana.
This early momentum continued into the early 21st century, as scientific publications, gray literature, and non-governmental organizations’ outreach efforts have sustained public interest in and concern about continuing land loss. Congress has also approved coastal restoration funds derived from offshore oil and gas revenue produced in the outer continental shelf to help restore and protect the coastal wetlands. A number of bills and measures have been passed and the state in 2009 was entitled to nearly $500 million, a five-fold increase from the $50 million allocated in the early part of the 21st century. Since then, the State Master Plan, and others studies have projected the price tag for rehabilitating the state’s disappearing wetlands from $50 billion to $100 billion. Money is starting to move through the legislative process and projects are moving from the design stage to implementation. This is good news, because the coast continues to disappear and the region’s citizens are increasingly at risk.
— Donald W. Davis, Louisiana State University