Evaluating Land Subsidence Rates and Their Implications for Land Loss in the Lower Mississippi River Basin

Water

Lei Zou²  Joshua Kent¹  Nina S.-N. Lam²  Heng Cai²  Yi Qiang²  Kenan Li² 

[1] Center for GeoInformatics, Louisiana State University, 200 Engineering Research & Development Building, Louisiana State University, Baton Rouge, LA 70803, USA;Department of Environmental Sciences, Louisiana State University, 1285 Energy, Coast & Environment Building, Louisiana State University, Baton Rouge, LA 70803, USA;

关键词: subsidence rates;    Mississippi Delta;    coastal Louisiana;    land loss;    sustainability;    Bayesian kriging;   

DOI  :  10.3390/w8010010

来源: mdpi

【 摘 要 】

High subsidence rates, along with eustatic sea-level change, sediment accumulation and shoreline erosion have led to widespread land loss and the deterioration of ecosystem health around the Lower Mississippi River Basin (LMRB). A proper evaluation of the spatial pattern of subsidence rates in the LMRB is the key to understanding the mechanisms of the submergence, estimating its potential impacts on land loss and the long-term sustainability of the region. Based on the subsidence rate data derived from benchmark surveys from 1922 to 1995, this paper constructed a subsidence rate surface for the region through the empirical Bayesian kriging (EBK) interpolation method. The results show that the subsidence rates in the region ranged from 1.7 to 29 mm/year, with an average rate of 9.4 mm/year. Subsidence rates increased from north to south as the outcome of both regional geophysical conditions and anthropogenic activities. Four areas of high subsidence rates were found, and they are located in Orleans, Jefferson, Terrebonne and Plaquemines parishes. A projection of future landscape loss using the interpolated subsidence rates reveals that areas below zero elevation in the LMRB will increase from 3.86% in 2004 to 19.79% in 2030 and 30.88% in 2050. This translates to a growing increase of areas that are vulnerable to land loss from 44.3 km²/year to 240.7 km²/year from 2011 to 2050. Under the same scenario, Lafourche, Plaquemines and Terrebonne parishes will experience serious loss of wetlands, whereas Orleans and Jefferson parishes will lose significant developed land, and Lafourche parish will endure severe loss of agriculture land.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.