Various Data – Coastal Land Loss

Topic Key

Causes and Effects of Land Loss

Coastal Wetlands

Community Perspectives

Earth Processes

Historical Profiles


Bald Cypress Survival Over Time

Source: Pontchartrain Conservancy

This graph plots the survival of bald cypress trees planted during restoration events.

Beach Nourishment

Source: Western Carolina University

This resource provides information about beach nourishment projects throughout the United States.

Bohemia Spillway

Source: Pontchartrain Conservancy

"The Bohemia Spillway is located in Plaquemines Parish on the east bank of the Mississippi River about 35 miles southeast of New Orleans, LA. In the 1920’s Mississippi River stages at New Orleans were becoming higher and more threatening, and so the Bohemia Spillway was authorized in 1924 by the Louisiana State legislature for the purpose of creating a river flood relief outlet and reducing flood risk to New Orleans.  The Bohemia Spillway was completed in the Fall of 1926 by the Orleans Levee District with the removal of the artificial Mississippi River levees, and remarkably just two months before the onset of the Great Flood of 1927. The spillway has a broad elevated river bank (natural levee) that slopes gently to the marsh and to Breton Sound. Since 1926, the natural levee of the Bohemia Spillway has been periodically overtopped during flood events on the Mississippi River."

Caernarvon Freshwater Diversion

Source: Pontchartrain Conservancy

"Located 15 miles downriver from New Orleans in Plaquemines Parish near the Plaquemines/St. Bernard Parish line is the Caernarvon Freshwater Diversion. Constructed in 1991, the diversion was designed to divert up to 8,000 cubic feet per second, approximately the volume of 2,353 large crawfish pots each second. Its intended purpose was to move fresh river water from the Mississippi into the local estuary, limiting the capture of sediment. Despite this, new land is building in the diversion's main catch basin, Big Mar Pond."

C-CAP Land Cover Atlas

Source: NOAA

"This online data viewer provides user-friendly access to coastal land cover and land cover change information developed through NOAA’s Coastal Change Analysis Program (C-CAP). The tool summarizes general change trends (such as forest losses or new development) and provides tables, maps, and reports to enhance communication and decision-making."

Census Data for Plaquemines Parish

Source: U.S. Census Bureau

"[Census] QuickFacts provides statistics for all states and counties, and for cities and towns with a population of 5,000 or more."

Coastal County Snapshots

Source: NOAA

"This online tool provides managers and citizens with easy-to-understand charts and graphs that describe complex coastal data. Users select a county of interest and the website does the rest, creating a helpful educational tool for governing bodies and citizen groups. Current snapshot topics include flood exposure, wetland benefits, and ocean and Great Lakes jobs."

Coastal Flood Exposure Mapper

Source: NOAA

"This online visualization tool supports communities that are assessing their coastal hazard risks and vulnerabilities. The tool creates a collection of user-defined maps that show the people, places, and natural resources exposed to coastal flooding."

Coastal Projects Map

Source: Coastal Protection and Restoration Authority

This map provides a spatial look at CPRA projects in Louisiana, sorted by project type. Users can access factsheets about each project by clicking on the icons.

For other CPRA maps, click here.

Coastal Resilience Mapping Portal

Source: The Nature Conservancy

"With its high incidence of storms and hurricanes and valuable ecological and economic resources, the Gulf region is a high-risk area with great potential to demonstrate natural risk reduction solutions. The Coastal Resilience approach and tools have been applied Gulf-wide and at specific sites, including those that help identify where to implement oyster reef restoration to meet social and ecological goals."

More information about this tool is available as a PDF or video. Information about this tool's use for specifically studying flood and sea level rise is available here.

CPRA Project Factsheets

Source: Coastal Protection and Restoration Authority

These project factsheets provide more information about the scope, cost, status, and location of various CPRA projects in the greater Phoenix, LA area. 

Estuarine Habitat Change 1956-2000

Source: Barataria-Terrebonne National Estuary Program 

These images provide habitat data in the Lower Barataria-Terrebonne Estuarine Basins for 1956, 1978, 1988, and 2000.

Land Building at the Caernarvon

Source: Pontchartrain Conservancy

This poster provides an overview of the geologic processes occurring at the Caernarvon Freshwater Diversion.

Louisiana's Coastal Master Plan (2017)

Source: Coastal Protection and Restoration Authority

"The 2017 Coastal Master Plan sets an ambitious path to respond to the loss of our coastal land and the threats from storm surge events. The master a list of projects that build or maintain land and reduce risk to our communities. Because the funding for all of those projects is not available now, the master plan identifies a long-term program of construction, operations and maintenance, and adaptive management that is guided by a robust and continuous planning process, to be implemented as funds become available..."

Appendix B: People and the Landscape

Attachment C4-11.2: Social Vulnerability Index

PC Research in the Bohemia Spillway

Source: Pontchartrain Conservancy

"The Bohemia Spillway is an 11-mile stretch of the east bank of the Mississippi River where the levees were removed in 1926. This allowed flood waters to overflow the bank, relieving pressure as far upstream as New Orleans. An unintended consequence is that this part of the river has had a nearly natural flooding cycle for the last 90 years." This poster highlights PC's research in the Bohemia Spillway.

Mardi Gras Pass

Source: Pontchartrain Conservancy

"Mardi Gras Pass is located in the Bohemia Spillway about 35 miles southeast of New Orleans at river mile 43.7. Mardi Gras Pass began to develop during the 2011 Mississippi River flood. In the course of a hydrologic survey conducted during the 2011 Mississippi River flood event, PC staff observed a process of overbank flow developing into a channelized flow across the crest of the natural levee. A breach was discovered in the roadway along the crest of the natural levee, which created a new channel. The breach continued to evolve through the natural forces of river flow. Headward erosion along the river across a forested bar allowed the channel to entirely breach to the Mississippi River in late February and early March 2012, at which time it was named Mardi Gras Pass. Mardi Gras Pass is now a free flowing distributary of the Mississippi River."

National Beach Nourishment Database

Source: APTIM

This resource provides data about beach nourishment projects throughout the United States.

National Levee Database

Source: U.S. Army Corps of Engineers / FEMA

This database includes information about government levee projects across the United States. For each levee project, user have access to information such as the levee structure, the surrounding area, risk assessments, elevation profiles, and more.


Plaquemines Risk Reduction Factsheet

Source: Coastal Protection and Restoration Authority

This factsheet provides information about the Plaquemines - Phoenix/Point a la Hache Nonstructural Risk Reduction Project that is part of the 2017 Louisiana Coastal Master Plan.

Pontchartrain Coastal Lines of Defense

Source: Pontchartrain Conservancy

"The coast has always been our first line of defense against hurricanes for southeast Louisiana. The [Comprehensive Habitat Management Plan] consists of over 100 projects and is the blueprint for restoration of the habitats in the Pontchartrain Basin. The CHMP projects were prioritized choosing the 10 habitat restoration projects that would also provide flood protection for the Greater New Orleans area. These projects became known as the Pontchartrain Coastal Lines of Defense Program."

Sea Level Rise - Delta Wildlife Refuge

Source: USGS, NOAA, U.S. DOI, EPA, Sea Grant, USFW

This informational sheet explores different sea level rise scenarios for the Delta National Wildlife Refuge in Venice, LA.

Southeast Louisiana Land Loss


Graphic showing both historical and projected coastal land loss in Louisiana from 1932-2050.

Swamp Restoration - Caernarvon

Source: Pontchartrain Conservancy

This poster provides a brief overview of PC's swamp restoration efforts in the Caernarvon Delta.

Tree Survival by Species

Source: Pontchartrain Conservancy

This resource provides data about the survival of different tree species planted during PC's restoration efforts.

Vegetation Survey

Source: Pontchartrain Conservancy

This resource provides data about tree species present at study sites in Summer 2018 and Winter 2019, as well as data on water depth, temperature, dissolved oxygen, and salinity.

To view just the Summer 2018 data, click here.

100+ Years of Land Change

Source: U.S. Geological Survey

"Coastal Louisiana has lost an average of 34 square miles of land, primarily marsh, per year for the last 50 years. From 1932 to 2000, coastal Louisiana has los 1,900 square miles of land, roughly an area the size of the state of Delaware. If nothing is done to stop this land loss, Louisiana could potentially lose approximately 700 square miles of the next 50 years. Further, Louisiana accounted for an estimated 90 percent of the coastal marsh loss in the lower 48 states during the 1990s."