Articles & Reports – Coastal Land Loss

Topic Key

Causes and Effects of Land Loss

Coastal Wetlands

Community Perspectives

Earth Processes

Historical Profiles


A river-dominated delta (Source: Modified from Nichols 2009)"

Restore the Mississippi River Delta - 2020

"In Louisiana, and in many places, the term “delta” is widely used. That’s mainly because we live on a delta – the Mississippi River Delta – and much of the land that comprises coastal Louisiana was built by the Mississippi and other rivers creating new deltas over millennia.

From a more technical standpoint, identifying what a delta is and its various components may not be as easy for most people. Many people picture a delta as a place where a river meets open water, and land protrudes outward as sediment accumulates near the mouth. What some may not know is that there is more to a delta than what we see in satellite images. Some of the most important parts of a delta are below the surface."

Interactions of factors that influence land loss. (Source: USGS)

United States Geological Survey

"This report represents a general overview of the primary causes and consequences of coastal land loss. Most of the examples and references are from states bordering the Gulf of Mexico and the Atlantic Ocean where the largest magnitudes and highest rates of coastal land losses in the United States are recorded (Dahl, 2000). The report serves as an introductory guide to the topics and literature on coastal land loss, and acts as a link to ongoing research being conducted by the U.S. Geological Survey."

Buildings accessible only by boat (Source: Barry Yeoman)

National Resources Defense Council - Apr 2020

"Ten years ago, as news of the BP oil disaster reached Louisiana’s Grand Bayou Indian Village, Rosina Philippe dispatched her brother Maurice Phillips on a reconnaissance mission. Phillips pointed his flatboat toward the Gulf of Mexico and motored through a series of canals and inlets until he reached a fertile fishing ground called Bay Jimmy, eight miles from home. He returned with a passenger: a brown pelican, alive but slathered in petroleum.

Philippe and her brother belong to the Atakapa-Ishak/Chawasha Tribe. They live in their ancestral village, an hour’s drive south of New Orleans near the town of Port Sulphur. Most of the tribe’s estimated 400 members live elsewhere, but a remnant remains in Grand Bayou, a community that has shrunk over the years as its land has slowly slipped into the surrounding waters."

Residents and planners review a map. (Source: Zack Smith)

LA SAFE - Dec 2017

"Flipping the script on typical state projects, where public engagement processes happen after the plans have already been drawn up, the meeting in Davant is part of a new approach to coastal planning oriented around residents’ ideas and values, which the state calls 'Louisiana’s Strategic Adaptations for Future Environments,' or LA SAFE for short. This 'co-design' process emerged from a robust public engagement effort that got its start in Plaquemines Parish in spring 2016, when local philanthropic group the Foundation for Louisiana teamed up with community planning and design firm Concordia and a host of environmental groups from the New Orleans area to define a new process for helping communities live in increasingly vulnerable coastal areas. Their guiding principles were transparency, communication, and trusting the 'wisdom of the crowd.'"

Louisiana's Birdfoot Delta in 1976 (Source: Jesse Allen /NASA)

American association of geographers - JAN 2018

"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."

A creek runs through a wetland (Source: NOAA)

NOAA - FEB 2020

"Look beyond the beauty of our coastal wetlands and you’ll find this habitat hard at work. Wetlands filter our water, protect our coastal communities from floods, and provide habitat for fish and other wildlife.

Coastal wetlands are some of the most productive ecosystems on Earth, and generate more than half of commercially harvested seafood in the United States.  In 2015, U.S. fisheries supported 1.6 million jobs (a 1 percent increase from 2011) and contributed $208 billion in sales (a 12 percent increase from 2011).

Development and agriculture contribute extra nutrients, pesticides, and silt to local rivers. Runoff from hard surfaces like concrete, asphalt, and rooftops is a leading cause of water pollution. Wetlands trap and filter these impurities, maintaining healthy rivers, bays and beaches."

Rev. Tyronne Edwards (Source: Zion Travelers Cooperative Center)

Restore the Mississippi River Delta - SEPT 2011

"Next in our Faces of the Delta series, you will meet Reverend Tyronne Edwards: 5th generation resident of Phoenix, La., community leader and organizer and coastal restoration advocate.

How has coastal land loss impacted your life?

'We lost everything we had during Hurricane Katrina. It was frightening to us. We now realize that if we had the right protection, the proper barriers–wetlands–we could protect our communities. If nothing is done with the wetlands, another Category Five will come and we’ll be destroyed again. While we rebuild our homes and our community, we keep restoration at the forefront because it’s all null and void if we don’t restore our wetlands.'"

Economic impact of Louisiana's coast. (Source: Walton Family Foundation)

The Atlantic - FEB 2018

"On average, a football field of land disappears into the Gulf of Mexico every 100 minutes. Over thousands of years, the Mississippi River carried sediment to the Louisiana coastline, building up marshes, wetlands and new land.

But today, because of canals and levees that constrict and confine the path of the river, the sediment cannot reach the delta to replenish the eroding wetlands.
Since the 1930s, Louisiana has lost close to 2,000 square miles of wetlands, an area roughly the size of Delaware."

"New Orleans 1863." (Source: Wells et al./ Library of Congress)

The Atlantic - FEB 2018

"Below sea level. It’s a universally known topographical factoid about the otherwise flat city of New Orleans, and one that got invoked ad nauseam during worldwide media coverage of Hurricane Katrina and its catastrophic aftermath in 2005. Locally, the phrase is intoned with a mix of civic rue and dark humor.

It’s also off by half. Depending on where exactly one frames the area measured, roughly 50 percent of greater New Orleans lies above sea level. That’s the good news. The bad news: It used to be 100 percent, before engineers accidentally sank half the city below the level of the sea. Their intentions were good, and they thought they were solving an old problem. Instead, they created a new and bigger one."

House on an eroding barrier island (Source: MRD)

Restore the Mississippi River Delta- 2020

"The Mississippi River Delta and coastal Louisiana are disappearing at an astonishing rate: a football field of wetlands vanishes into open water every 100 minutes. Since the 1930s, Louisiana has lost over 2,000 square miles of land, an area roughly the size of Delaware. Many factors have contributed to this collapse."

Cover artwork (Source: Barnes and Virgets, LSU)

Environmental Defense Fund - Mar 2017

"Louisiana is facing a land loss crisis – more than 2,000 square miles of land have been lost over the last 100 years, and an equal amount could potentially be lost over the next 50 years. This loss puts businesses, homes, infrastructure and whole communities at risk.

The risk of continued land loss is concentrated in coastal Louisiana, but the economic implications will spread throughout the nation due to the state's importance in shipping, energy production, chemicals and other sectors."

To access the full study, click here.

Maps: only solid land (Source: LaTigre)

The New Yorker - MAR 2019

"Plaquemines is where the river meets the sea. On maps, it appears as a thick, muscular arm stretching into the Gulf of Mexico, with the Mississippi running, like a ropy blue vein, down the center. At the very end of the arm, the main channel divides into three, an arrangement that calls to mind fingers or claws, hence the area’s name—the Bird’s Foot.

Seen from the air, the parish has a very different look. If it’s an arm, it’s a horribly emaciated one. For most of its length—more than sixty miles—it’s practically all vein. What little solid land there is clings to the river in two skinny strips.

Plaquemines has the distinction—a dubious one, at best—of being among the fastest-disappearing places on Earth."

Wetlands south of New Orleans after Katrina (Source: NASA/USGS)

The Times-Picayune - SEPT 2015

"The scars of coastal loss, accelerated by Hurricane Katrina in 2005, still can be seen on the wetlands surrounding New Orleans, visible in before and after images taken by combined camera and sensor devices aboard NOAA Landsat satellites.

Wetlands surrounding Delacroix are shown a week before Katrina, with normal vegetation showing up as bright green and water as blue. The Caernarvon Freshwater Diversion Project releases water from the Mississippi River into the Big Mar, and it eventually flows southeast through these wetlands."

Residents at an LA SAFE planning meeting. (Source: LA OCD)

Georgetown Climate Center - 2020

"This report is composed of 17 individual case studies. Each one tells a different story about how states, local governments, and communities across the country are approaching questions about managed retreat. Together, the case studies highlight how different types of legal and policy tools are being considered and implemented across a range of jurisdictions — from urban, suburban, and rural to riverine and coastal — to help support new and ongoing discussions on the subject. These case studies are intended to provide transferable lessons and potential management practices for coastal state and local policymakers evaluating managed retreat as one part of a strategy to adapt to climate change on the coast."

A preliminary illustration of the Mid-Breton Diversion (Source: CPRA)

Engineering News-Record - AUG 2018

"Engineers are working to help reconnect the Mississippi River to Louisiana’s sediment-starved wetlands in an effort to rebuild some of the land that is disappearing at a rate of almost 11,000 acres a year—or roughly a football field an hour.

The diversions will be major civil works projects without compare. The work will require careful scheduling to maintain flood protection as the Mississippi River levee comes down and a diversion gate is put in its place. And that will be the easy part. The projects must be operated to divert the most river sediment and the least amount of water to minimize the impact on the people and wildlife in Barataria Bay. Too much river water could flood communities and kill fisheries."

Current and planned diversions in Louisiana. (Source: Dan Swenson)

The Times-Picayune / The New Orleans Advocate - AUG 2019

"Two Mississippi River diversions created to reduce salinity levels in Breton Sound and the Barataria Basin, and a crevasse that cut through the river’s east bank levee in Plaquemines Parish, actually caused the loss of more wetlands than they helped build, according to a new study led by LSU researchers.

But experts caution that the study does not necessarily portend similar results for the two massive diversions planned along the lower Mississippi in the next few years — diversions designed with the specific goal of land-building."

"The Tahoma Dam in North Carolina." (Source: Joshua Moore, iStock)

Public Broadcasting Service - May 2019

"About two-thirds of the world’s longest rivers are no longer free-flowing, thanks to damming, diversions, and other human-made disruptions, according to new research. The findings, published today in the journal Nature, spell trouble for people and wildlife worldwide who rely on the natural paths of rivers for water, food, irrigation, and more.

'The benefits of free-flowing rivers are countless,' Denielle Perry, a water resources geographer at Northern Arizona University in Flagstaff who was not involved in the study, told Stefan Lovgren at National Geographic. 'Rivers are the lifeblood of the planet.'"

Image of the offshore shelf in the Gulf of Mexico. (Source PC)

Pontchartrain Conservancy - 2020

"The coast has always been our first line of defense against hurricanes for southeast Louisiana. Recognizing this, Pontchartrain Conservancy (PC) developed the Multiple Lines of Defense Strategy designed to help save our coast. In the simplest terms, this strategy highlighted below shows how natural features of our coast (like barrier islands, marshes, and ridges) compliment man-made features (like levees) to protect the Greater New Orleans area from hurricanes."

Delacroix Island Wetlands, 2015 (Source: NASA/USGS)

NASA Earth Observatory - Aug 2015

"The wetlands surrounding Delacroix, a fishing town to the southeast of New Orleans, were some of the hardest hit by the hurricane. Pounding surf, driving winds, and a potent storm surge transformed the marshes by picking apart mats of dead grass, stirring up and disbursing soft underlying sediments, scouring several new channels, and depositing leftover sediment and debris in new areas.

This pair of false-color images shows the transformation. The Thematic Mapper on Landsat 5 acquired the top image a week before the storm hit. The Operational Land Imager (OLI) on Landsat 8 acquired the second image in August 2015. "

Darilyn Turner of ZTCC (Source: Darilyn Turner)

Yale climate connections - NOV 2018

"After [Hurricane Katrina], community members formed a faith-based nonprofit called the Zion Travelers Cooperative Center. Their work began as a grassroots recovery effort, with neighbors helping neighbors gut houses and remove debris, to prepare for rebuilding.

Today, the group’s work continues. They educate residents about climate change and how rising seas and increasingly intense storms threaten the area. And members advocate for solutions that could help protect them, including wetlands restoration and stronger levees.”

"Carola van Gelder of the Sand Motor." (Source: Chris Granger)

The New Orleans Advocate - MAR 2020

"The Sand Motor is a nature-based alternative to the Netherlands’ famed network of walls, levees and sea gates, and much cheaper than the vast, multimillion-dollar beach rebuilds Louisiana is undertaking along its sandy barrier islands and rapidly deteriorating coastline.

Where Louisiana’s projects seek to re-create almost precisely what was lost, the Dutch simply pile the sand in a strategic location where it will be pushed naturally into places where it will still provide protection. The method is slow — so it lasts longer — and it’s much cheaper."

Caernarvon Diversion and Bohemia Spilllway (Source: PC)

Restore the mississippi river delta - dec 2014

"Natural land-building deltaic processes of the Mississippi River Delta have been severely limited by artificial river levees, which prevent water and sediment from flowing over the banks during spring floods. To counteract the effects of severing the connection between the river and the delta, focus has been placed on reconnecting the river to the surrounding wetlands by the creation of artificial outlets, also called diversions."

Scholarly Research

Wetland in Southwestern Louisiana. (Source: USGS)

Rimal (Georgia state university) - 2017

"The wetlands of the coastal Louisiana have been disappearing at an alarming rate. The rate was further accelerated during the Hurricane Katrina. Hurricane Katrina converted a large area of wetland into open water by bulk removal of vegetation, flooding, and killing of plants through the salt water inundation. The aim of this study was to quantify wetland loss rates in a high salinity wetland of St. Bernard Parish, Louisiana before and after Hurricane Katrina made landfall. Change-detection-mapping and analysis, using Landsat TM images, was used for generating the change matrices. Images from 1990 and 2010 were analyzed to estimate total wetland loss and the wetland loss contributed by Hurricane Katrina over the 20-year period. The analysis revealed that wetland loss in the study area during Hurricane Katrina accounted for over half (65%) of the total land lost over a 20-year period (1990 to 2010)."

"Land reclamation around Bohai Bay, China (Source: Dr. Tian)."

Li et al. - 2017

"Coastal wetlands mainly include ecosystems of mangroves, coral reefs, salt marsh, and sea grass beds. As the buffer zone between land and sea, they are frequently threatened from both sides. The world coastal wetland lost more than 50% of its area in the 20th century, largely before their great value, such as wave attenuation, erosion control, biodiversity support, and carbon sequestration, was fully recognized. World wetland loss and degradation was accelerated in the last three decades, caused by both anthropogenic and natural factors... Profound consequences have been caused by coastal wetland loss, such as habitat loss for wild species, CO2 and N2O emission from land reclamation and aquaculture, and flooding. Great efforts have been made to restore coastal wetlands, but challenges remain due to lack of knowledge about interactions between vegetation and morphological dynamics. Compromise among the different functionalities remains a challenge during restoration of coastal wetlands, especially when faced with highly profitable coastal land use."

Erosion rates in various marsh sediment samples. (Source: Feagin et al.)

Nature Scientific Reports - Aug 2018

"Changes in coastal morphology have broad consequences for the sustainability of coastal communities, structures and ecosystems. Although coasts are monitored locally in many places, understanding long-term changes at a global scale remains a challenge. Here we present a global and consistent evaluation of coastal morphodynamics over 32 years (1984–2015) based on satellite observations."

Global maps showing areas of accretion and erosion. (Source: Mentaschi et al.)

Nature Scientific Reports - Aug 2018

"Changes in coastal morphology have broad consequences for the sustainability of coastal communities, structures and ecosystems. Although coasts are monitored locally in many places, understanding long-term changes at a global scale remains a challenge. Here we present a global and consistent evaluation of coastal morphodynamics over 32 years (1984–2015) based on satellite observations."

HortTechnology Journal. (Source: ASHS)


"It is essential that environmental education be integrated into the science classroom. Many educators use environmental education to enhance student science-based knowledge. Studies have shown that introducing environmental education not only raises science scores, but other subject scores as well (Wakefield, 2001), therefore the use of environmental education in the classroom maybe an excellent strategy to obtain student interest and increase student knowledge of all subject areas. The Louisiana Sea Grant College Program (Sea Grant) has taken this idea and put it into action."

Global hotspots of beach erosion and accretion. (Source: Luijendijk et al.)

Nature Scientific Reports - Apr 2018

"Coastal zones constitute one of the most heavily populated and developed land zones in the world. Despite the utility and economic benefits that coasts provide, there is no reliable global-scale assessment of historical shoreline change trends. Here, via the use of freely available optical satellite images captured since 1984, in conjunction with sophisticated image interrogation and analysis methods, we present a global-scale assessment of the occurrence of sandy beaches and rates of shoreline change therein... The majority of the sandy shorelines in marine protected areas are eroding, raising cause for serious concern."


Cycle between inequality and climate change. (Source: Islam & Winkel)

United Nations DESA - Oct 2020

"This paper offers a unifying conceptual framework for understanding the relationship between climate change and “within-country inequalities,” referred here collectively as “social inequality.” Available evidence indicates that this relationship is characterized by a vicious cycle, whereby initial inequality causes the disadvantaged groups to suffer disproportionately from the adverse effects of climate change, resulting in greater subsequent inequality"

"Scoring Examples for Direct Climate Effects" (p. 21)

National Estuarine Research Reserve System - May 2015

"The National Estuarine Research Reserve System uses its living laboratories to find solutions to crucial issues facing America’s coasts, including climate change and resilience. The input of land managers, decision-makers, and researchers across agencies was sought to ensure that the Climate Change Vulnerability Assessment Tool for Coastal Habitats (CCVATCH) would provide results that could be directly applied to current management and conservation decisions. Changes in climate have direct effects on ecosystems and also interact with current stressors to impact vital coastal habitats. Adaptive capacity, either natural traits of the system or potential management actions, can lessen the impacts of climate change."

Cover page

NOAA/Sea grant - nov 2010

"The purpose of this self-assessment is to provide community leaders with a simple and inexpensive method of predicting if their community will reach and maintain an acceptable level of functioning after a disaster. Experienced local planners, engineers, floodplain managers or administrators can complete this self-assessment using existing sources of information from their community.

The goal is for every community to become highly resilient. The assessment may identify problems your community should address before the next disaster and where resources should be allocated."

Part of the cover art by Ziigwanikwe (Source: Katy Bresette)


"This document is intended to empower tribal governments, federal and state agencies, non-governmental organizations (NGOs), individual landowners and others to incorporate Anishinaabeg perspectives, specifically from the Great Lakes region, into a climate adaptation framework. We recognize the shortcomings of this document in our attempt to incorporate indigenous concepts, language, and cultural practices; a single document written in English can’t fully capture what we intend to express. We hope that the perspectives given here offer users an additional lens with which to view the environment and facilitate a more culturally appropriate approach to working with tribal nations."

Lobes of the Mississippi River (Source: modified from Draut et al., 2005).

National Research Council - 2006

"During the past 50 years, coastal Louisiana has suffered catastrophic land loss due to both natural and human causes. This loss has increased storm vulnerability and amplified risks to lives, property, and economies--a fact underscored by Hurricanes Katrina and Rita. Drawing Louisiana's New Map reviews a restoration plan proposed by the U.S. Army Corps of Engineers and the State of Louisiana, finding that, although the individual projects in the study are scientifically sound, there should be more and larger scale projects that provide a comprehensive approach to addressing land loss over such a large area. More importantly, the study should be guided by a detailed map of the expected future landscape of coastal Louisiana that is developed from agreed upon goals for the region and the nation."

Land area change from 1932 - 2015. (Source: USGS)

U.S. Geological Survey - 2017

"Coastal Louisiana wetlands are one of the most critically threatened environments in the United States. These wetlands are in peril because Louisiana currently experiences greater coastal wetland loss than all other States in the contiguous United States combined. The analyses of landscape change presented here have utilized historical surveys, aerial, and satellite data to quantify landscape changes from 1932 to 2016. Analyses show that coastal Louisiana has experienced a net change in land area of approximately -4,833 square kilometers (modeled estimate: -5,197 +/- 443 square kilometers) from 1932 to 2016. This net change in land area amounts to a decrease of approximately 25 percent of the 1932 land area."

To access the map directly, click here.

To access a PDF version of the report, click here.

Diagram of a shoreline under different tidal levels. (Source: SAGE)

U.S. Army Corps of Engineers / NOAA - FEB 2015

"Innovative approaches are necessary as our coastal communities and shorelines are facing escalating risks from more powerful storms, accelerated sea-level rise, and changing precipitation patterns that can result in dramatic economic losses. While the threats of these events may be inevitable, understanding how to adapt to the impact is important as we explore how solutions will ensure the resilience of our coastal communities and shorelines.

This brochure presents a continuum of green to gray shoreline stabilization techniques, highlighting Living Shorelines, that help reduce coastal risks and improve resiliency though an integrated approach that draws from the full array of coastal risk reduction measures."

Competency sub group (Source: The Water Institute)

The Water Institute - Dec 2018

"During five meetings in 2018, representative community members in St. Bernard Parish were involved in a fact-finding and participatory modeling activity. Areas of risk were identified, and potential natural and nature-based solutions were tested through modeling. The models were adjusted based on the community group’s feedback. This summary outlines how this project moved forward, what was discovered through this new process, and if the community found value in the approach."

"Existing Levee Systems in Plaquemines Parish." (Source: USACE)

Plaquemines Parish - 2020

"Coastal restoration plays a paramount role in protecting Plaquemines’ citizens from storm surge and maximizes protection will allow for the expansion of Plaquemines’ economic base. The purpose of the coastal restoration element of the Comprehensive Master Plan is to review and assess coastal restoration plans and activities in Plaquemines Parish. The goal of this section is to help the Parish government more effectively plan and prepare for future growth in a manner that offers maximum protection for residential, commercial, and industrial investment.

Coastal restoration measures have been recognized as sustainable solutions along with flood protection levees to provide the Parish citizens with adequate flood protection against storm surge."

A marsh. (Source: RESTORE)

Restore the Mississippi River Delta - 2020

"With so many causes behind the land loss crisis, a variety of coastal restoration strategies are needed for effective restoration — there is no single solution. When restoration projects are strategically planned and operated together, they are more effective. Employing the full suite of restoration tools available allows land to be built and maintained in a way that surpasses the benefits of any single project operating alone. To understand the combined effects of different types of restoration projects, it is important to understand the individual project benefits and their limitations."

Cover artwork for the report

"This guide provides a brief introduction to key physical impacts of climate change on estuaries and a review of on- the-ground adaptation options available to coastal managers to reduce their systems’ vulnerability to climate change impacts. Reducing the emissions of greenhouse gases, referred to as “mitigation,” is a necessary component of the overall response to climate change, and can help avoid, reduce, or delay future impacts. however, this guide focuses on climate change adaptation for estuaries and coastal areas because: 1) estuaries are highly and uniquely vulnerable to climate change, 2) adaptation will be necessary to address impacts resulting from warming which is already unavoidable due to past and current emissions, and 3) adaptation can help reduce the long-term costs associated with climate change."

Gulf Coast (Source: Pendleton et al., 2010)

NASEM - 2018

"The U.S. Gulf of Mexico Coast...provides a valuable setting to study deeply connected natural and human interactions and feedbacks that have led to a complex, interconnected coastal system. The physical landscape in the region has changed significantly due to broad-scale, long-term processes such as coastal subsidence and river sediment deposition, as well as short-term episodic events such as hurricanes. Modifications from human activities, including building levees and canals and constructing buildings and roads, have left their own imprint on the natural landscape. ... Promoting the resilience and maintaining the habitability of the Gulf Coast into the future will need improved understanding of the coupled natural-human coastal system, as well as effective sharing of this understanding in support of decision making and policies."