Research (2000 - 2011) at the St. Petersburg Coastal and Marine Science Center focused on better understanding the physical processes and human activities that contributed to historical wetland loss in coastal Louisiana and the spatial and temporal trends of that loss.
Wetland losses in the northern Gulf Coast region of the United States are so extensive they represent critical concerns to government environmental agencies and natural resource managers. In coastal Louisiana, wetland loss has been such an important environmental and economic issue that decades of scientific research have been dedicated to the topic. Since the trend was first recognized in the late 1960s, billions of dollars in state and federal funding have been earmarked for coastal restoration projects intended to compensate for some of the historical wetland losses. In support of that effort, research (2000 - 2011) at the St. Petersburg Coastal and Marine Science Center (SPCMSC) focused on better understanding the physical processes and human activities that contributed to historical wetland loss in coastal Louisiana and the spatial and temporal trends of that loss.
The physical processes (land-surface subsidence and sediment erosion) responsible for historical wetland loss were quantified by comparing marsh-surface elevations, water depths, and vertical displacements of stratigraphic contacts that were correlated between short sediment cores at 10 study areas in the Mississippi River delta plain and six sites at Sabine National Wildlife Refuge (SNWR) in the western chenier plain. The sequential development and two-dimensional extent of land loss at the study areas were described by comparing historical maps, aerial photographs, and satellite imagery; and the temporal and spatial trends of historical wetland loss were compared with historical subsidence rates and hydrocarbon production trends for the same period. The total three-dimensional accommodation space that formed as the result of historical wetland loss was estimated by integrating the spatial data with emergent-marsh elevations and bathymetry from the study areas.
Study Area and Geologic Setting
Delta Plain
The 10 delta-plain study areas encompassed several different physiographic and geologic settings, including: (1) an upper delta-plain levee flank of the Mississippi River (Ironton), (2) a pre-existing upper delta-plain interior channel (Bayou Perot), (3) four upper delta-plain interdistributary areas (Bully Camp, Pointe au Chien, DeLarge, and Madison Bay), (4) three lower delta-plain interdistributary areas (Bay St. Elaine, Leeville, and Fourchon), and (5) a lower delta-plain beach-ridge margin area (Caminada).
Western Chenier Plain
The 6 western chenier-plain study areas were located in Sabine National Wildlife Refuge, which encompasses about 500 km2 of coastal wetlands between Sabine and Calcasieu Lakes in the western chenier plain. The refuge occupies a broad, shore-parallel, topographically low area that formed between the topographically higher beach ridges along the gulf shoreline to the south and Pleistocene upland areas to the north.
Research and Results
Analysis of historical satellite imagery and previously interpreted land-classification datasets identified more than 4,600 km2 of low-lying wetlands in coastal Louisiana that converted to open water between 1932 and 2004.
Wetland Subsidence and Erosion
The two primary physical processes responsible for historical wetland loss in coastal Louisiana are land-surface subsidence and erosion.
Induced Subsidence Related to Hydrocarbon Production
Historical delta-plain subsidence rates were assessed by analyzing tide-gauge records, elevation changes at benchmarks between repeat leveling surveys, and Global Positioning System (GPS) vertical velocities at Continuously Operating Reference Stations (CORS).
Historical Accommodation Formation
Bathymetric data acquired at the Madison Bay, Point au Chien, Bully Camp, Leeville, Fourchon, Caminada, and Sabine National Wildlife Refuge study areas provided average one-dimensional (1D) (vertical) accommodation distances at those sites. These results were integrated with the two-dimensional (2D) (area) extent of historical wetland loss from 1956 to 2004 to estimate the total 3D (volume) accommodation space that formed historically on the western chenier and delta plains.
Photos of project fieldwork.
Below are other science projects associated with this project.
Study Area and Geologic Setting - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Historical Wetland Loss - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Wetland Subsidence and Erosion - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Induced Subsidence Related to Hydrocarbon Production - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Historical Accommodation Formation - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Natural Subsidence and Sea-Level Rise - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Photo Gallery - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Below are publications associated with this project.
Recent subsidence and erosion at diverse wetland sites in the southeastern Mississippi Delta Plain
Constraining rates and trends of historical wetland loss, Mississippi River Delta Plain, south-central Louisiana
Evidence of regional subsidence and associated interior wetland loss induced by hydrocarbon production, Gulf Coast region, USA
Historical subsidence and wetland loss in the Mississippi delta plain
Causes of hot-spot wetland loss in the Mississippi delta plain
Subsurface controls on historical subsidence rates and associated wetland loss in southcentral Louisiana
- Overview
Research (2000 - 2011) at the St. Petersburg Coastal and Marine Science Center focused on better understanding the physical processes and human activities that contributed to historical wetland loss in coastal Louisiana and the spatial and temporal trends of that loss.
Wetland losses in the northern Gulf Coast region of the United States are so extensive they represent critical concerns to government environmental agencies and natural resource managers. In coastal Louisiana, wetland loss has been such an important environmental and economic issue that decades of scientific research have been dedicated to the topic. Since the trend was first recognized in the late 1960s, billions of dollars in state and federal funding have been earmarked for coastal restoration projects intended to compensate for some of the historical wetland losses. In support of that effort, research (2000 - 2011) at the St. Petersburg Coastal and Marine Science Center (SPCMSC) focused on better understanding the physical processes and human activities that contributed to historical wetland loss in coastal Louisiana and the spatial and temporal trends of that loss.
The physical processes (land-surface subsidence and sediment erosion) responsible for historical wetland loss were quantified by comparing marsh-surface elevations, water depths, and vertical displacements of stratigraphic contacts that were correlated between short sediment cores at 10 study areas in the Mississippi River delta plain and six sites at Sabine National Wildlife Refuge (SNWR) in the western chenier plain. The sequential development and two-dimensional extent of land loss at the study areas were described by comparing historical maps, aerial photographs, and satellite imagery; and the temporal and spatial trends of historical wetland loss were compared with historical subsidence rates and hydrocarbon production trends for the same period. The total three-dimensional accommodation space that formed as the result of historical wetland loss was estimated by integrating the spatial data with emergent-marsh elevations and bathymetry from the study areas.
Study Area and Geologic Setting
Delta Plain
The 10 delta-plain study areas encompassed several different physiographic and geologic settings, including: (1) an upper delta-plain levee flank of the Mississippi River (Ironton), (2) a pre-existing upper delta-plain interior channel (Bayou Perot), (3) four upper delta-plain interdistributary areas (Bully Camp, Pointe au Chien, DeLarge, and Madison Bay), (4) three lower delta-plain interdistributary areas (Bay St. Elaine, Leeville, and Fourchon), and (5) a lower delta-plain beach-ridge margin area (Caminada).
Western Chenier Plain
The 6 western chenier-plain study areas were located in Sabine National Wildlife Refuge, which encompasses about 500 km2 of coastal wetlands between Sabine and Calcasieu Lakes in the western chenier plain. The refuge occupies a broad, shore-parallel, topographically low area that formed between the topographically higher beach ridges along the gulf shoreline to the south and Pleistocene upland areas to the north.
Research and Results
Analysis of historical satellite imagery and previously interpreted land-classification datasets identified more than 4,600 km2 of low-lying wetlands in coastal Louisiana that converted to open water between 1932 and 2004.
Wetland Subsidence and Erosion
The two primary physical processes responsible for historical wetland loss in coastal Louisiana are land-surface subsidence and erosion.
Induced Subsidence Related to Hydrocarbon Production
Historical delta-plain subsidence rates were assessed by analyzing tide-gauge records, elevation changes at benchmarks between repeat leveling surveys, and Global Positioning System (GPS) vertical velocities at Continuously Operating Reference Stations (CORS).
Historical Accommodation Formation
Bathymetric data acquired at the Madison Bay, Point au Chien, Bully Camp, Leeville, Fourchon, Caminada, and Sabine National Wildlife Refuge study areas provided average one-dimensional (1D) (vertical) accommodation distances at those sites. These results were integrated with the two-dimensional (2D) (area) extent of historical wetland loss from 1956 to 2004 to estimate the total 3D (volume) accommodation space that formed historically on the western chenier and delta plains.
Photos of project fieldwork.
- Science
Below are other science projects associated with this project.
Study Area and Geologic Setting - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
The Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin project included 10 delta-plain study areas 6 western chenier-plain study areas.Historical Wetland Loss - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Analysis of historical satellite imagery and previously interpreted land-classification datasets identified more than 4,600 km2 of low-lying wetlands in coastal Louisiana that converted to open water between 1932 and 2004.Wetland Subsidence and Erosion - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
The magnitudes of subsidence and erosion at the wetland-loss core sites were estimated by comparing marsh-surface elevations, water depths, and vertical displacements of stratigraphic contacts that were correlated between short sediment cores.Induced Subsidence Related to Hydrocarbon Production - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
One of the primary goals of this project was to test the hypothesis that long-term, large-volume hydrocarbon production along the Gulf Coast resulted in land-surface subsidence, reactivation of deep-seated faults, and wetland loss in Texas and Louisiana.Historical Accommodation Formation - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Bathymetric data acquired at the Madison Bay, Point au Chien, Bully Camp, Leeville, Fourchon, Caminada, and Sabine National Wildlife Refuge study areas provided average one-dimensional accommodation distances at those sites. These results were integrated with the two-dimensional extent of historical wetland loss from 1956 to 2004 to estimate the total 3D (volume) accommodation space that formed...Natural Subsidence and Sea-Level Rise - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Geologic proxies may shed light on long-term environmental trends and stability of the Louisiana coastal marsh. The combined processes of accretion, sea-level rise and subsidence influence wetland elevation and determine marsh stability.Photo Gallery - Subsidence and Wetland Loss Related to Fluid Energy Production, Gulf Coast Basin
Gallery of photos taken during fieldwork. - Publications
Below are publications associated with this project.
Recent subsidence and erosion at diverse wetland sites in the southeastern Mississippi Delta Plain
A prior study (U.S. Geological Survey Open-File Report 2005-1216) examined historical land- and water-area changes and estimated magnitudes of land subsidence and erosion at five wetland sites in the Terrebonne hydrologic basin of the Mississippi delta plain. The present study extends that work by analyzing interior wetland loss and relative magnitudes of subsidence and erosion at five additionalConstraining rates and trends of historical wetland loss, Mississippi River Delta Plain, south-central Louisiana
The timing, magnitude, and rate of wetland loss were described for five wetland-loss hotspots in the Terrebonne Basin of the Mississippi River delta plain. Land and water areas were mapped for 34 dates between 1956 and 2004 from historical National Wetlands Inventory (NWI) datasets, aerial photographs, and Landsat Thematic Mapper (TM) satellite images. Since 1956, the emergent land area at theEvidence of regional subsidence and associated interior wetland loss induced by hydrocarbon production, Gulf Coast region, USA
Analysis of remote images, elevation surveys, stratigraphic cross-sections, and hydrocarbon production data demonstrates that extensive areas of wetland loss in the northern Gulf Coast region of the United States were associated with large-volume fluid production from mature petroleum fields. Interior wetland losses at many sites in coastal Louisiana and Texas are attributed largely to acceleratedHistorical subsidence and wetland loss in the Mississippi delta plain
Five representative areas of the Mississippi River delta plain were investigated using remote images, marsh elevations, water depths, sediment cores, and radiocarbon dates to estimate the timing, magnitudes, and relative rates of marsh erosion and land subsidence at geological and historical time scales. In the Terrebonne-Lafourche region of rapid interior-wetland loss, former marshes are now submCauses of hot-spot wetland loss in the Mississippi delta plain
Field surveys and sediment cores were used to estimate marsh erosion and land subsidence at Madison Bay, a well-known wetland loss hot spot in coastal Louisiana. Former marshes of Madison Bay are under about 1 m of water. Nearly two-thirds of the permanent flooding was caused by rapid subsidence in the late 1960s, whereas the other third was caused by subsequent erosion. Subsidence rates near MadiSubsurface controls on historical subsidence rates and associated wetland loss in southcentral Louisiana
Two regional releveling profiles and six tide gauges provide a basis for evaluating recent rates of delta plain subsidence in southcentral Louisiana. Analyses of these records demonstrate close correlations among highest historical rates of subsidence, rapid wetland losses, large volume hydrocarbon production, and probable reactivation of deep subsurface faults. Other researchers have demonstrated