Land And Forest Area Changes In The Vicinity Of The Mississippi River Gulf Outlet, Central Wetlands Region, 1935-2010
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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As part of the overall Mississippi River Gulf Outlet MRGO Ecosystem Restoration Study, the Central Wetlands Unit CWU is a critical coastal restoration project proposed to mitigate the effects of the MRGO dredging and dredged material placement in southeastern coastal Louisiana. An in-depth knowledge of recent and historical coastal landscape history is a key knowledge element required by project managers to make informed decisions for implementing the overall CWU restoration strategy. The goal of this study was to provide a refined landscape history for the CWU that both exceeds and supplements information provided by existing coastal habitat and land loss data sets. The research identified and quantified recent and historical land change trends and general forested wetland habitat changes within the CWU from 1935 to 2010. The CWU land area changes were analyzed using a series of land-water data sets obtained from classified Landsat Thematic Mapper TM satellite imagery, historic aerial photography and topographic quadrangles. Wetland forested habitat changes were evaluated using two pre-construction 1935 and 1956 and two post-construction 1965 and 1974 data sets bracketing the construction of the MRGO 1965. The study revealed that the CWU net land loss from 1935 to 2010 was 6,688 acres with a land area change rate of -87.6 or - 11.1 acresyr r sq 0.68. Rapid loss of forested habitat also occurred within the CWU throughout the 1935 to 1974 analysis period. In 1935, the CWU consisted of 13,924 acres of forested habitat and by 1974 virtually all were lost. The primary events affecting historical landscape change within the CWU over the past 75 years are linked to 1 cumulative hurricane impacts causing physical removal of marsh, 2 partial flooding of impounded areas after Hurricane Betsy, 3 construction of the MRGO, and 4 salinity increases causing habitat conversion.
- Geology, Geochemistry and Mineralogy
- Hydrology, Limnology and Potamology