A synoptic examination of causes of land loss in southern Louisiana as related to the exploitation of subsurface geologic resources

Journal of Coastal Research
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Abstract

During the last 80 years, Louisiana has been losing wetlands at an average rate of 62 km2/y (24 mi2/y) for an accumulated loss of approximately 4900 km2 (1900 mi2). The loss seems to be the combined result of natural and anthropogenic causes that are behind primarily land subsidence averaging about 10 mm/y (0.4 in/y) coinciding with a sea level rise now at 3 mm/y (0.1 in/y), both contributing to coastal inundation. Upon completing extensive review of often controversial and conflicting views only synoptically reported here, conclusions reached by applying Monte Carlo simulation include: (1) geodetic measurements are consistent with independently postulated causes of regional subsidence; (2) ranking of subsidence factors shows that the main contributor to the regional subsidence is adjustment to sediment load in the form of lithosphere flexure followed by normal faulting dipping basinward, which combined, account on average for 70% of the subsidence, with compaction accounting for another 23%; and (3) production of oil and gas plays a tertiary role. The literature supports the historical view that before experiencing engineering modifications across the catchment area, sedimentation from the Mississippi River system was able to build a prograding coastline by overcoming subsidence rates of similar magnitude with more generous sediment loads of coarser particle size. Sea level rise will become an increasingly dominant factor in land loss only if the acceleration predicted by simulation model scenarios materializes. Wetland losses most likely will continue for as long as there is no compensation to counterbalance the negative effects of land subsidence and sea level rise, with the latter determining the pace of future losses.

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Publication type Article
Publication Subtype Journal Article
Title A synoptic examination of causes of land loss in southern Louisiana as related to the exploitation of subsurface geologic resources
Series title Journal of Coastal Research
DOI 10.2112/JCOASTRES-D-13-00046.1
Volume 30
Issue 5
Year Published 2014
Language English
Publisher Coastal Education and Research Foundation
Contributing office(s) Eastern Energy Resources Science Center
Description 20 p.
First page 1025
Last page 1044
Country United States
State Louisiana
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