Mixed sediment for sustainable ecosystem restoration of Louisiana

Abstract

Globally, human activities have contributed to the degradation of the coastal landscape and the Mississippi River Delta Plain (MRDP) is no exception. It is facing an ecocatastrophe caused in part by human intervention. This degradation and extreme rates of land loss threaten a range of key national assets and locally important communities. Restoration of Louisiana’s environmentally sensitive wetlands, marshes, and barrier islands is in the national interest. Human activities have disrupted natural sediment transport to the MRDP. Sediment is trapped behind locks and dams upstream, decreasing fluvial sediment loads and preventing a naturally sustainable deltaic coast. Locally, coastal communities depend on a sustainable surrounding ecosystem for their existence. The fast-degrading coastal Louisiana needs frequent emplacement of sediment where the objective is not limited to ecosystem restoration only but most importantly to mitigate the pervasive land loss. Thus, sediment is critical for survival. Implementation of the Coastal Master Plan (CMP) for restoration and protection of coastal Louisiana depends heavily on a comprehensive Louisiana Sediment Management Plan (LASMP) that integrates various restoration quality/compatible sediment emplacement mechanisms. Louisiana’s sediment need is significant and can only be met with a balance of both sand and mixed sediment. There is an increasing need for mixed sediment, as sand alone is not sufficient and not always the most appropriate sediment for restoration projects. Mixed sediment has been used for marsh restoration for quite some time in Louisiana. This paper defines mixed sediment as it applies to restoration in Louisiana and emphasizes the need to identify and preserve sources of mixed sediment to be used for the construction of planned restoration projects.