Vulnerability assessment of water resources using GIS, remote sensing and SWAT model - a case study: the upper part of Dong Nai river basin, Vietnam

Water resources vulnerability assessment provides the basis for the policymakers and the stakeholders regarding the state of the river basin to be focused for its better management. This research aims to assess the vulnerability index (VI) of the upper part of the Dong Nai (UPDN) river basin, which plays a crucial role for the socio-economic development of Ho Chi Minh City and 10 other provinces in the Southeast Vietnam, as well as its sub-basins. This study accounts from the year 1994 to 2030 (36 years) by using an integrated solution between the GIS, remote sensing (RS) and SWAT model in collaboration with guidelines prepared by United Nations Environment Programme (UNEP) and Peking University. Results from the land cover classification of Landsat images in the period of 1994-2020 revealed that the forest area decreased by 324,586 ha (approximately 29.4% of the basin area) and greatly influenced the VI. The UPDN basin's water vulnerability was a moderate level of which VI was 0.276, 0.303 and 0.310 in 1994, 2004 and 2014, respectively. By 2030, the projected VI value could expect to be 0.318 under the climate change scenarios of the representative concentration pathway (RCP4.5). At the sub-basins, Dak Nong and Dak R'Keh were two of the most vulnerable sub-basins of which VIs have could reach approximately 0.4 categorized as highly vulnerable areas. The results evidenced that the integrated techniques could be an efficient approach to provide useful information on the status of water resources to stakeholders in evaluating comprehensive options in terms of sustainable water resources management.