Assessment of the Spatial and Temporal Distribution of Water Resources in Vietnam’s Central Highlands Using the SWAT Model

This study aims to assess the spatial and temporal distribution of water resources of the Central Highlands climatic region, which includes five basins, namely Be, Ta Lai, La Nga, Ba, and 3S. The flow was simulated for the period of seven to ten years during 1982–1991, 1991–1999, 1987–1996, 1997–2006, and 2000–2007, corresponding to the above-mentioned basins. After calibrating and validating the models, the simulation results were analyzed, and the maps of monthly and annual flow depth were created using QGIS. The results show that surface water resources in this region can be accurately simulated by the SWAT model, with obtained values of the correlation coefficient R 2 and the efficiency coefficient NSI of the model calibration and validation period at a good level (>0.7). Specifically, the R 2 ranged between 0.82 – 0.94 in the calibration and between 0.83 – 0.95 in the validation. These figures for NSE were 0.77 - 0.89 and 0.79 - 0.89, respectively. The average annual flow depths of the above basins were estimated as 1210 mm, 1078 mm, 1276 mm, 816 mm, and 999 mm, correspondingly. The simulations show clear spatial and temporal differences in water distribution: the south maintains a higher flow year-round, the north has low runoff in the middle of the dry season, the central and western areas experience higher flows in the middle the wet season and the dry season often comes earlier than in other basins, and the east sees low flow for for many months of the year. These findings can assist improved water management planning in the region.