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Land loss and subsidence in the Mekong River Delta : A Surface Elevation Table (SET) program

This program investigates the continuous land loss and subsidence in the Mekong River Delta, using the Surface Elevation Table (SET) method. It explores the causes, impacts, and future risks associated with land loss and subsidence in the region.

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Land loss and subsidence in the Mekong River Delta : A Surface Elevation Table (SET) program

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  1. Land loss and subsidence in the Mekong River Delta: A Surface Elevation Table (SET) program Le Xuan Thuyen Natural Science University at Ho-Chi Minh lxthuyen@hcmus.edu.vn

  2. Ảnh: TUẤN VŨ Mekong River Delta 2009 • Evidence of continuous land loss • Initiation of SET-MH monitoring • network in the Mekong River Delta 2006 • Future investigation

  3. Shoreline retreat 8/2009 2/2001 Camau cape

  4. Harris-Galveston Subsidence District USGS picture found at approximate location of maximum subsidence in the United States identified by research efforts of Dr. Joseph F. Poland (pictured). Signs on pole show approximate altitude of land surface in 1925, 1955, and 1977. The site is in the San Joaquin Valley southwest of Mendota, California

  5. Submergence risk Submergence risk maps of the Mekong Delta with sea level rise +1 m, corresponding to the worst scenario A1F1 in the reports of the Intergovernmental Committee (IPCC, 2007) ≈ 39 % surface under water in 2100 Scenarios of climate change, sea level rise for Vietnam. MONDRE, March 2012 Timing and degree of projected submergence (percentage of inundation) of a given land surface or feature 0.5 meter above current sea level heights in relation to a constructed sea level scenario based on maximum A1F1 projection (IPCC, 2007) and a net subsidence rate of 9 mm/yr. emerging issue 39 Reason of these differences – likely land subsidence ? • Or imply an unexpected role of subsidence in mentioned scenarios of submergence risk • this 'unpredictable variability' behaves in a more predictable way than previously assumed 2070 Doyle, T.W., Day, R.H., and Michot, T.C., 2010, Development of sea level rise scenarios for climate change assessments of the Mekong Delta, Vietnam: U.S. Geological Survey Open-File Report 2010–1165, 110 p.

  6. Great speed of subsidence: 1- 3 cm/y ! (2007-2010) Surface change simulated from InSAR multidate imageries and ground water withrawal (2007 – 2010) Laura E. Erban, Steven M. Gorelick, Howard A. Zebker, Scott Fendorf, (2013). Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence. PNAS | August 20, 2013 | vol. 110 | no. 34 | 13751–13756 Mean daily water level at Vung Tau gauge station (2007-2013)

  7. Initial Wetland Surface Surface Elevation Table and Marker Horizon Network designed for shallow subsidence monitoring Subsided Wetland Surface Bench Mark with Geodetic Control Surface Elevation Table (SET) Tide Gauge Sea Level Upland Rise Depth of SET measurement integration Shallow Subsidence Holocene strata Deep Subsidence http://www.pwrc.usgs.gov/set.

  8. Global SET Network This is not a strategically designed network. It is an ad hoc collection of study sites. However the data can be used to analyze higher order questions, such as comparisons among regions and wetland types.

  9. Surface Elevation Table (SET) The surface elevation table method provides high resolution measures (mm scale) of wetlandelevation change Rod Surface Elevation Table (RSET) Benchmark depth = 10 - 25 m The method, which utilises a simple, low-cost tool, is financially and technically accessible to every country with coastal wet­lands. Science daily, Apr. 25, 2013 Salt marsh in New York City Cahoon, D., Reed, D., Day, J. 1995. Estimating shallow subsidence in microtidal salt marshes of the southeastern United States: Kaye and Barghoorn revisited. Marine Geology 128:1-9.

  10. Can Gio Biosphere Reserve, Mekong River Delta, July 2010 Subsidence rate measuring by SET technics Rhizophora

  11. Natural disaster Energy spectrum of Durian Storm 00:10 GMT 5 Dec.2006 SET measurement in the Cangio mangrove: intact and collapsed mangrove areas. March 2013 Root decomposition accelerates subsidence

  12. Camau cape Highest coastal line modification SET reading First mission, July 2010 August 2013

  13. Floodplain Tramchim national park Wetland training August 2012

  14. Hoa An March 2013 Freshwater swamp Hoa An August 2013

  15. Preliminary results of land subsidence monitoring in the coastal zone - mangrove forest in the MRD Tongle Chma May 2013 Tongle Sap May 2013 Tramchim Agust 2012 Hoa-an March 2013 14.2mm/y Great speed of subsidence: 1- 3 cm/y ! (2007-2010) Surface change simulated from InSAR multidate imageries and ground water withdrawal (2007 – 2010) Laura E. Erban, Steven M. Gorelick, Howard A. Zebker, Scott Fendorf, (2013). Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence. PNAS | August 20, 2013 | vol. 110 | no. 34 | 13751–13756

  16. Future investigation

  17. ? Dec 2013 Xuân Thủy Future investigation • Expansion of SET – MH network To raise the quality of dataset May 2013 Oct 2012 Cantho city • Different subjects April 2012 - Driving factors, integration - Modelling at different scales August 2012 Tràm Chim July 2010 Cần Giờ July 2011 March 2013 March 2011 (Cù Lao Dung) June 2011 Mũi Cà Mau June 2011

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