Geology Reports⌕ Search

Geology topics

Scott A. Wilson

Publications and source records attributed to Scott A. Wilson.

8 recordsLinked to original sources
USGS2018

Barataria and Terrebonne Bays: Chapter F in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

The study area included in the Barataria and Terrebonne Bays vignette of southeastern Louisiana spans eastward from Terrebonne Bay to Barataria Bay (Figure 1) and includes portions of Terrebonne, Lafourche, St. Charles, Jefferson, Orleans, Plaquemines, and St. Bernard Parishes. This area falls between the Mississippi River on the east and northeast, extends down through the western shore of Lake Salvador and the Dixie Delta Canal, then runs west to Houma and follows Louisiana Route 315 to the coast; Barataria and Terrebonne Bays are separated from each other by Bayou Lafourche.

Louisiana↗
USGS2018

Mississippi Delta: Chapter G in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

The Mississippi River Delta, the tip of the longest river in North America, is located in the coastal plains of southeastern Louisiana. The study area included in the Mississippi River Delta vignette of southeastern Louisiana follows the Mississippi River southward from Port Sulphur within the modern Plaquemines-Balize Delta lobe (Figure 1). It extends eastward through Long Bay into California Bay and then encapsulates most of the land to the east of the river; it extends south into Lake Washington and Lake Robinson, then to the Gulf of Mexico, and includes the land to the west of the river. All of this area is within Plaquemines Parish. The mouth of the Mississippi includes four subdeltas (West Bay, Cubit’s Gap, Baptiste Collette, and Garden Island Bay) which began formation between 1839 and 1891 (Coleman and others, 1998). As of 2010, the total land area from Venice, LA to the gulf was 357.50 square km (138.03 square miles) and had ranged from 208.08 square km (80.34 square miles) to 393.70 square km (152.01 square miles) since 1973 (Couvillion and others, 2011).

Louisiana↗
USGS2013

Statewide summary for Louisiana: Chapter E in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

Throughout the past century, emergent wetlands have been declining across the Gulf of Mexico. Emergent wetland ecosystems provide a variety of resources, including plant and wildlife habitat, commercial and recreational economic activity, and natural barriers against storms. As emergent wetland losses increase, so does the need for information on the causes and effects of this loss, emergent wetland mapping, monitoring and restoration efforts, and education. The U.S. Geological Survey and the U.S. Environmental Protection Agency’s Gulf of Mexico Program are committed to restoring, enhancing, and protecting these important ecosystems. The purpose of this report is to provide scientists, managers, and citizens with valuable baseline information on the status and trends of emergent wetlands along the coast of the Gulf of Mexico. This study examines the emergent wetlands of eight individual estuarine areas within the northern Gulf of Mexico region, as well as presenting statewide summaries for Texas, Louisiana, Mississippi, Alabama, and Florida. Each estuarine area is detailed in vignettes that address current status and historical trends of estuarine and palustrine emergent wetlands, emergent wetlands mapping and monitoring, causes of status change, restoration and enhancement activities, background information for the study area, and the methodology employed to analyze and document the historical trends and current status of emergent wetlands. This chapter examines the estuaries of Louisiana.

Louisiana↗
USGS2011

Bank erosion of navigation canals in the western and central Gulf of Mexico

Erosion of navigation canal banks is a direct cause of land loss, but there has been little quantitative analysis to determine why certain major canals exhibit faster widening rates (indicative of erosion) than others in the coastal zones of Texas, Louisiana, Mississippi, and Alabama. We hypothesize that navigation canals exhibit varying rates of erosion based on soil properties of the embankment substrate, vegetation type, geologic region (derived from digital versions of state geologic maps), and the presence or absence of canal bank armaments (that is, rock rip-rap, concrete bulkheads, or other shoreline protection structures). The first objective of this project was to map the shoreline position and substrate along both banks of the navigation canals, which were digitized from 3 different time periods of aerial photography spanning the years of 1978/79 to 2005/06. The second objective was to quantify the erosion rates of the navigation canals in the study area and to determine whether differences in erosion rates are related to embankment substrate, vegetation type, geologic region, or soil type. To measure changes in shoreline position over time, transects spaced at 50-m (164-ft) intervals were intersected with shorelines from all three time periods, and an annual rate of change was calculated for each transect. Mean annual rates of shoreline change ranged from 1.75 m/year (5.74 ft/year) on the west side of the Atchafalaya River, La., where there was shoreline advancement or canal narrowing, to -3.29 m/year (-10.79 ft/year) on the south side of the Theodore Ship Channel, Ala., where there was shoreline retreat or erosion. Statistical analysis indicated that there were significant differences in shoreline retreat rates according to geologic region and marsh vegetation type, and a weak relationship with soil organic content. This information can be used to better estimate future land loss rates associated with navigation canals and to prioritize the location of restoration and erosion mitigation efforts. Combining all canals together, our results also showed that canal erosion rates have slowed in recent years, with an average canal widening rate of -0.99 m/year (-3.25 ft/year) for the 1996/98-2005/06 time period compared to -1.71 m/year (-5.61 ft/year) for the earlier 1978/79-1996/98 time period. Future research could focus on obtaining detailed vessel traffic information for individual canals, which is likely a factor that influences canal bank erosion rates.

Open-File Report↗
USGS2005

Shorebird habitat availability assessment of agricultural fields using a digital aerial video system

Field and wetland conditions in the rice prairies of Louisiana and Texas are highly dynamic habitats. Rice prairies are important habitat for many species of migratory birds, including shorebirds, wading birds, and waterfowl. Ground sampling a variety of fields to assess habitat availability is very labor intensive, and accessibility to private lands makes statistical habitat sampling almost impossible. Aerial video is a tool we can use for assessing availability of these highly ephemeral habitats because of the short-duration repeatability of the surveys. The strong statistical basis of line transect theory allows quantitative estimation of habitat availability. We used ground surveys of field conditions and shorebird ground counts to correlate spectral signatures with shorebird habitat availability. This video system can also be used to identify and map distribution of invasive plant species known to affect suitability of stopover habitat for shorebirds and landbirds.

Louisiana↗
USGS1997

Community involvement in a multimedia outreach project for Caddo Lake, Texas

Caddo Lake is located in northeast Texas and northwest Louisiana and is the largest freshwater lake in Texas. A portion of the lake in Texas has been designated a "Wetland of International Significance" under the Ramsar Convention of the United Nations. The human community in the watershed has experienced a number of hydrological alterations to Caddo Lake over the last 100 years by the Federal Government. Thus, many landowners in the area have become organized to protect Caddo Lake against what some view as harmful further alterations. In 1992, the U.S. Congress appropriated funds for an initiative to conduct baseline studies of the natural resources of Caddo Lake in order to foster ecotourism and economic development in the surrounding counties. For the information gathering part of the initiative and in response to negative criticism of the Caddo Lake Initiative expressed at a public meeting, the U.S. Geological Survey's National Wetlands Research Center invited public participation in developing a multimedia outreach system to improve the understanding of the natural resources at Caddo Lake and provide information about the studies. In the development of the outreach system we sought to strengthen working relationships with the State of Texas, local governments, and grassroots citizens groups. The outreach system consisted of an MS Windows-based interactive CD-ROM package that incorporated pictures, sound, animation, and video footage of the lake and the local culture. Public involvement in system development served as a catalyst for changing community perceptions about Federal and states studies at Caddo Lake and fostered community endorsement of the Caddo Lake Initiative.

Texas↗
USGS1994

Nest monitoring using a micro-video camera

A system is described that utilizes a battery operated micro-video camera mounted on an extendible pole for monitoring high nests. The video image is transmitted to a hand-held monitor at ground level and provides accurate information about the contents of high nests.

Journal of Field Ornithology↗