Surface Water Evolution (2001-2017) at the Cambodia/Vietnam Border in the Upper Mekong Delta Using Satellite MODIS Observations

Studying the spatial and temporal distribution of surface water resources is critical, especially in highly populated areas and in regions under climate change pressure. There is an increasing number of satellite Earth observations that can provide information to monitor surface water at global scale. However, mapping surface waters at local and regional scales is still a challenge for numerous reasons (insufficient spatial resolution, vegetation or cloud opacity, limited time-frequency or time-record, information content of the instrument, lack in global retrieval method, interpretability of results, etc.). In this paper, we use 17 years of the MODIS (MODerate-resolution Imaging Spectro-radiometer) observations at a 8-day resolution. This satellite dataset is combined with ground expertise to analyse the evolution of surface waters at the Cambodia/Vietnam border in the Upper Mekong Delta. The trends and evolution of surface waters are very significant and contrasted, illustrating the impact of agriculture practices and dykes construction. In most of the study area in Cambodia. surface water areas show a decreasing trend but with a strong inter-annual variability. In specific areas, an increase of the wet surfaces is even observed. Ground expertise and historical knowledge of the development of the territory enable to link the decrease to ongoing excavation of drainage canals and the increase of deforestation and land reclamation, exposing flooded surfaces previously hidden by vegetation cover. By contrast, in Vietnam, the decreasing trend in wet surfaces is very clear and can be explained by the development of dykes dating back to the 1990s with an acceleration in the late 2000s as part of a national strategy of agriculture intensification. This study shows that coupling satellite data with ground-expertise allows to monitor surface waters at mesoscale (

[1]  E. LeDrew,et al.  Principal Components Analysis of Arctic Ice Conditions between 1978 and 1987 as Observed from the SMMR Data Record , 1996 .

[2]  S. K. McFeeters.  The use of the Normalized Difference Water Index (NDWI) in the delineation of open water features , 1996 .

[3]  D. Peddle,et al.  TEMPORAL MIXTURE ANALYSIS OF ARCTIC SEA ICE IMAGERY: A NEW APPROACH FOR MONITORING ENVIRONMENTAL CHANGE , 1998 .

[4]  H. Storch,et al.  Statistical Analysis in Climate Research , 2000 .

[5]  Robert G. Bryant,et al.  Investigation of flood inundation on playas within the Zone of Chotts, using a time-series of AVHRR , 2002 .

[6]  Hanqiu Xu.  Modification of normalised difference water index (NDWI) to enhance open water features in remotely sensed imagery , 2006 .

[7]  Changsheng Li,et al.  Mapping paddy rice agriculture in South and Southeast Asia using multi-temporal MODIS images , 2006 .

[8]  T. Sakamoto,et al.  Detecting temporal changes in the extent of annual flooding within the cambodia and the vietnamese mekong delta from MODIS time-series imagery , 2007 .

[9]  F. Aires,et al.  Global inundation dynamics inferred from multiple satellite observations, 1993–2000 , 2007 .

[10]  D. Biggs.  Breaking from the Colonial Mold: Water Engineering and the Failure of Nation-Building in the Plain of Reeds, Vietnam , 2008, Technology and culture.

[11]  Heng Tao Shen,et al.  Principal Component Analysis , 2009, Encyclopedia of Biometrics.

[12]  Planning Atlas of the Lower Mekong River Basin , 2011 .

[13]  William Cronon,et al.  Quagmire: Nation-Building and Nature in the Mekong Delta , 2011 .

[14]  Christopher Small,et al.  Spatiotemporal dimensionality and Time-Space characterization of multitemporal imagery , 2012 .

[15]  S. Dech,et al.  Comparison and enhancement of MODIS cloud mask products for Southeast Asia , 2013 .

[16]  Filipe Aires,et al.  Rotation of Eofs by the Independent Component Analysis: Towards a Solution of the Mixing Problem in the Decomposition of Geophysical Time Series , 2013 .

[17]  Xinwu Li,et al.  Flood Mapping and Flood Dynamics of the Mekong Delta: ENVISAT-ASAR-WSM Based Time Series Analyses , 2013, Remote. Sens..

[18]  Urs Wegmüller,et al.  Multi-temporal Synthetic Aperture Radar Metrics Applied to Map Open Water Bodies , 2014, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[19]  Antonio Iodice,et al.  Sentinel-1 for Monitoring Reservoirs: A Performance Analysis , 2014, Remote. Sens..

[20]  A. Schneider,et al.  Mapping rice paddy extent and intensification in the Vietnamese Mekong River Delta with dense time stacks of Landsat data , 2015 .

[21]  Stephen Darby,et al.  Evaluating sustainable adaptation strategies for vulnerable mega-deltas using system dynamics modelling: Rice agriculture in the Mekong Delta's An Giang Province, Vietnam. , 2016, The Science of the total environment.

[22]  George S. Vergos,et al.  Use of MODIS satellite images for detailed lake morphometry: Application to basins with large water level fluctuations , 2016, Int. J. Appl. Earth Obs. Geoinformation.

[23]  J. Pekel,et al.  High-resolution mapping of global surface water and its long-term changes , 2016, Nature.

[24]  F. Aires,et al.  Surface Water Monitoring within Cambodia and the Vietnamese Mekong Delta over a Year, with Sentinel-1 SAR Observations , 2017 .

[25]  D. Tran,et al.  Assessing impacts of dike construction on the flood dynamics of the Mekong Delta , 2017 .

[26]  Bruno Merz,et al.  Has dyke development in the Vietnamese Mekong Delta shifted flood hazard downstream , 2017 .

[27]  F. Aires,et al.  A global dynamic long-term inundation extent dataset at high spatial resolution derived through downscaling of satellite observations , 2017 .

[28]  D. Tran,et al.  Barriers to Implementing Irrigation and Drainage Policies in An Giang Province, Mekong Delta, Vietnam , 2018 .

[29]  Qing He,et al.  Water Level Reconstruction and Prediction Based on Space-Borne Sensors: A Case Study in the Mekong and Yangtze River Basins , 2018, Sensors.

[30]  Binh Pham-Duc.  Satellite remote sensing of the variability of the continental hydrology cycle in the lower Mekong basin over the last two decades , 2018 .

[31]  Gilles Belaud,et al.  Surface water monitoring in small water bodies: potential and limits of multi-sensor Landsat time series , 2018, Hydrology and Earth System Sciences.

[32]  F. Aires,et al.  Comparison of visible and multi-satellite global inundation datasets at high-spatial resolution , 2018, Remote Sensing of Environment.

[33]  D. Tran,et al.  Stakeholders’ assessment of dike-protected and flood-based alternatives from a sustainable livelihood perspective in An Giang Province, Mekong Delta, Vietnam , 2018 .

[34]  V. Thanh,et al.  Flooding in the Mekong Delta: Impact of dyke systems on downstream hydrodynamics , 2019 .

[35]  Nguon Vichet,et al.  MODIS-Based Investigation of Flood Areas in Southern Cambodia from 2002–2013 , 2019, Environments.

[36]  Christopher Small,et al.  Coupled Spatiotemporal Characterization of Monsoon Cloud Cover and Vegetation Phenology , 2017, Remote. Sens..

[37]  V. Thanh,et al.  Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics , 2020 .