Land loss is the term typically used to refer to the conversion of coastal land to open water by natural processes and human activities. The term land loss includes coastal erosion. It is much broader term than coastal erosion because land loss also includes land converted to open water around the edges of estuaries and interior bays and lakes and by subsidence of coastal plain wetlands. The most important causes of land loss in coastal plains are erosion, inadequate sediment supply to beaches and wetlands, subsidence, and global sea level rise. The mixture of processes responsible for most of the land loss will vary occurring the specific part of a coastal plain being examined. The definition of and loss does not include the loss of coastal lands to agriculture, urbanization, or other development.
Although seemingly related, wetland loss, is defined differently than land loss. Commonly, wetland loss is defined as the conversion of vegetated wetlands into either uplands or drained areas; unvegetated wetlands (e.g., mudflats); or (submerged habitats (open water). According to this, and similar definitions, wetland loss includes both land loss and land consumption as components of it. In historic times, both wetland and land loss typically are the result of a varying, often controversial mixture of natural and anthropogenic factors. There are other definitions of wetland loss commonly used. For example, some researchers defined wetland loss as "the substantial removal of wetland from its ecologic role under natural conditions."
Land loss and deltas
Because of a highly variable combination of sea level rise, sediment starvation, coastal erosion, wetland deterioration, various types of subsidence, and various human activities, land loss within delta plains is a significant global problem. The large delta plains of the world, including the Danube, Ganges, Brahmaputra, Indus, Mahanadi, Mangoky, McKenzie, Mississippi, Niger, Nile, Shatt el Arab, Volga, Yellow, Yukon, and Zambezi deltas, have all suffered significant land loss as the result of either coastal erosion, internal conversion of wetlands to open water, or a combination of both. For the 15 deltas studied by Coleman and others, these deltas experienced a total irreversible land loss of 5,104 km2 (1,971 sq mi) of wetlands between the early 1980s and 2002. During this period, the total average land loss for all of these deltas was about 41 km2 (16 sq mi) per year. In case of the Mississippi River Delta, they found that in a 12-year period, some 253 km2 (98 sq mi) of wetlands had been converted to new open water at a rate of 21 km2 (8.1 sq mi) per year.
- Morton, R.A., 2003. An overview of coastal land loss: with emphasis on the Southeastern United States. Open-File report 03-337. US Geological Survey, Center for Coastal and Watershed Studies, St. Petersburg, Florida. 28 pp.
- Britsch, L.D. and Kemp III, E.B., 1990. Land loss rates: Mississippi River deltaic plain. Technical Report no. WES/TR/GL-90-2. Geotechnical Lab, Army Waterways Experiment Station, Vicksburg, Mississippi.
- Barras, J.A., P.E. Bourgeois, and L.R. Handley. 1994. Land loss in coastal Louisiana 1956-90. National Biological Survey, National Wetlands Research Center Open File Report 94-01. 4 pp.
- Boesch, D.F., Josselyn, M.N., Mehta, A.J., Morris, J.T., Nuttle, W.K., Simenstad, C.A. and Swift, D.J., 1994. Scientific assessment of coastal wetland loss, restoration and management in Louisiana. Journal of Coastal Research, Special Issue No. 20, pp.1-103.
- Chan, A.W. and Zoback, M.D., 2007. The role of hydrocarbon production on land subsidence and fault reactivation in the Louisiana coastal zone. Journal of Coastal Research, 23(3) pp.771-786.
- Craig, N.J., Turner, R.E. and Day, J.W., 1979. Land loss in coastal Louisiana (USA). Environmental Management, 3(2), pp.133-144.
- Coleman, J.M., Huh, O.K. and Braud Jr, D., 2008. Wetland loss in world deltas. Journal of Coastal Research, 24(sp1), pp. 1-14.
|This geomorphology article is a stub. You can help Wikipedia by expanding it.|