*Kim-Anh Nguyen1, Yuei-An Liou1, Phan Duong Cao2, Philip Mindehoud3
(1.National Central University, 2.University of Tsukuba, 3.University of Padova)
Keywords:land subsidence;, land use, land cover; , Mekong Delta , Sentinel-1, Landsat
Vietnamese Mekong Delta (VMD) is known as the second largest granary in the world, while its rice paddy yield has been seriously threatened by the alarmingly enhanced extreme weathers and human intervention in the upstream. After serious drought in 2016, the Vietnamese government enforced the Resolution No.120/NQ-CP on 17/11/2017 and Directive No. 04/CT-TTg on 4/2/2016 aiming for sustainable development of the Mekong Delta to adapt to climate change. These introduced strategies with new visions and strategic directions that lead the economic development of VMD focusing on aquaculture, fruit, and rice products, corresponding to transformation in land use and land cover (LULC). Consequently, LULC change in the Mekong Delta from paddy rice field to aquaculture has been observed significant, and LULC change has been found to accelerate the subsidence over aquaculture lands and wetlands. This paper presents the LULC change in the VMD, land subsidence and their relationship in the timeframe from 2014 to 2019. Land subsidence map and its value were generated from Sentinel-1 imagery from ESA (European Space Agency), LULC maps were created from the Landsat data time series. The accuracy of the LULC classification is 95% with Kappa coefficient 0.94. The land subsidence was validated with measured data. Results show that significant land subsidence generally occurred in aquaculture land, open water and mangrove wetland, which were significantly increased in terms of areas from the LULC change analysis. LULC change and its relationship with land subsidence in the VMD were also discussed. Results of the study provide useful information for the authorities to design plans to mitigate human impacts and reduce the risk while dealing with climate change.