what problems are caused by dredging out wetlands

These restorations potentially include dredged channels in wetlands that were built throughout the world for a variety of reasons including agriculture, forestry, colonial expansion, and disease reduction ( Rippon, 2000 Mann, 2008 Ash, 2017). Wetland conservation and restoration projects create wildlife habitat and carbon sinks, protect and enhance cultural heritage, resilience, and economic values and are now numerous ( Costanza et al., 2014 United Nations General Assembly, 2019 United Nations Environment Programme, 2021 zu Ermgassen et al., 2021) the arguments for them are now forceful and there is intense interest to conserve and restore wetlands to something near to their pre-disturbed conditions. Backfilling canals can be done on the 27 thousand abandoned canals across this coast for a low cost compared to other restoration strategies. The spoil bank was restored wetland habitat within a few years, and the open water of the canal was 70% re-vegetated after 39 years if there was no soil “plug” placed at the canal entrance during backfilling. The re-vegetation of these 16 canals were compared to backfilled canals in the Barataria Preserve of the Jean Lafitte Historical National Park.

Success occurred where the natural hydrology was not artificially constrained by these structures. Sixteen of the 33 disturbed areas are now mostly restored to wetlands, and seventeen were compromised by re-dredging and other factors such as being surrounded by other canals or embedded within water level control structures.

Thirty-three canals backfilled in the 1980s as opportunistic permit requirements were examined to determine their re-vegetation after 39 years. The dredged material placed alongside the canal forms continuous levees and can be dragged back into the canal to start wetland restoration (backfilling) but is rarely done.

Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, United Statesĭredging to create canals and channels in wetlands is widespread and is a major cause of dramatically high wetland loss rates in coastal Louisiana.

What problems are caused by dredging out wetlands