Coastal Louisiana recent land loss and canal impacts

Abstract

Annual coastal land loss in the sedimentary deltaic plain of southern Louisiana is 102 km2, which is correlated with man-made canal surface area. The relationships between land loss and canals are both direct and indirect and are modified by the deltaic substrate, distance to the coast, and availability of new sediments. Loss rates are highest in the youngest of the former deltas nearest the coast; they are lowest in the more consolidated sediments far from the coast. The average estimate for land loss at zero canal density in the six regression equations developed was 0.09%±0.13% annually, the present land loss rates approach 0 8% annually Although additional analyses are needed, we conclude that canals are causally related to a significant portion of the total coastal land loss rates The relation probably involves an interruption of local and regional hydrologic regimes. Reduction of the present acceleration in land loss rates is possible by managing present canals more effectively, by not permitting new ones, and by changing the design of new canals to allow more natural water flow