Location: Watershed Physical Processes ResearchTitle: Laboratory and field investigations of marsh edge erosion Author
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/10/2013
Publication Date: 6/10/2013
Citation: Chen, Q., Ozeren, Y., Zhang, G., Wren, D., Wu, W., Jadhav, R., Parker, K., and Pant, H. Laboratory and field investigations of marsh edge erosion. pp 311-337 In Abdul, K. and Wu, W. (eds.) Sediment Transport: Monitoring, Modeling and Management. Nova Science Publishers, Inc. 390 pp. 2013. Interpretive Summary: In the world’s major deltaic plains, land loss has been estimated to be 95 square kilometers per year over the past 14 years (Coleman et al., 2008). The Mississippi River delta in Louisiana, USA, has in particular experienced persistent wetland loss. During the period of 1932–2010, the total land loss in coastal Louisiana was 5,400 square kilometers, and the rate of loss from 1985–2010 was 47.5 km2/yr, which is equivalent to losing a football field of land every hour (Couvillion et al., 2011). The mechanisms for wetland loss are poorly understood, and, for preservation of marshlands, much more information is needed. The work described here seeks to help address the lack of knowledge regarding marshland losses and marsh edge erosion through both field and laboratory studies.
Technical Abstract: This chapter presents the laboratory experiments and field observations of marsh edge erosion. The marsh retreat rate in a field study site in Terrebonne Bay, Louisiana, was measured using GPS systems and aerial photographs. The wave environment was also measured in order to correlate the marsh edge retreat rate and wave conditions. A physical model of marsh edge was constructed in a laboratory using the intact marsh edge samples collected from the field, and its erosion by wave undercutting was recorded. In- situ and laboratory testing were carried out to determine and understand the critical shear stress for marsh soil erosion. Other laboratory measurements, including organic matter content, water content, root content, and particle size distribution, were also conducted. The critical shear stress was found to depend on soil depth and root content.