Hyper-Temporal Land Area Change Rates in Coastal Louisiana from 1973 to 2015

Science Center Objects

This study analyzes changes in the extent of land in coastal Louisiana by using an average of 81 datasets (multiple dates of satellite data from 1973 to 2014) for summarizing land and water areas.

Land Area Change in Coastal Louisiana (1932 to 2010)
Land Area Change in Coastal Louisiana (1932 to 2010)

The Science Issue and Relevance: Previous research has shown that coastal Louisiana has undergone a net change in wetland area of about -1,883 square miles from 1932 to 2010. This net change in land area amounts to a decrease of about 25 percent of the 1932 land area. This study continually researches the occurrence and rates of wetland change as a result of natural and anthropogenic factors. This work is relevant to the USGS Ecosystems Mission area as it directly relates to four of the five mission area goals.

Methodology for Addressing the Issue: This study analyzes changes in the extent of land in coastal Louisiana by using an average of 81 datasets (multiple dates of satellite data from 1973 to 2014) for summarizing land and water areas. The datasets were derived from three sources: Landsat Multi-Spectral Scanner (MSS) data (1973–1979), Landsat Thematic Mapper (TM) satellite imagery (1985–2011), and Operational Land Imager (OLI) imagery (2013-2014), which were used to develop indices pertaining to land/water composition. The methodology used in this study relies heavily on the use of a modified Normalized Difference Water Index. The goal of this analysis is to quantify land area change over time to document and understand the short- and long-term effects of various causal mechanisms of wetland loss.

Future Steps: While this task focuses on documenting wetland change and quantifying the rates of that change, future efforts will seek to investigate the causes of those changes. 

Location of the Study: Throughout the Louisiana coastal zone, Latitude: 29.678°, Longitude: -91.552°