Sustainable Erosion Remediation and Restoration Measures in South Louisiana Navigation Channels

Abstract

The Gulf Intracoastal Water Way (GIWW) and the Mississippi River-Gulf Outlet (MR-GO) are two navigation channels constructed by the US Army Corps of Engineers (USACE) in south Louisiana. Each of these navigation channels was dredged in previously undisturbed wetlands with no bank stabilization or erosion protection along its length. The GIWW and the MR-GO have had significant impacts on soil conditions, bank stability, and erosion in south Louisiana affecting both the natural and built environment. Aerial photographs covering the decades since their construction illustrate severe land loss and degradation in and around the navigation channels. Contributing to the instabilities were wake energy, salt water intrusion, and loss of land mass continuity in fragile ecosystems. The soil instabilities and erosion, in turn, lead to more severe hurricane damages, loss of coastal habitat, and further loss of channel structure. Faced with mounting navigational, environmental, and political issues resulting from the degradation of the GIWW and MR-GO, the US Army Corps of Engineers and the State of Louisiana had a unique opportunity to study and implement innovative and sustainable countermeasures for the surface and subsurface erosion prevalent in each channel. Political, economic, and social factors surrounding each channel lead to different remediation and restoration measures with respect to erosion prevention.