Evaluation of Land Use Changes on Stream Discharge by SWAT Model and Remote Sensing in Agro-Forestry Basin in Nghinh Tuong Subwatershed, Northern Vietnam
The purpose of this study is to examine the impact of land-use changes on stream discharge in the Nghinh Tuong watershed (a branch of the Cau river) in Northern Vietnam using the “Soil and Water Assessment Tool (SWAT)” model and GIS. The watershed was 56 percent forested, 30 percent agricultural, and the rest was undeveloped.
Stream discharge observation data from 2001 to 2010 was used for the calibration period, whereas the validation period was from 2011 to 2020.
The results revealed that two coefficients (NSE and PBIAS) were 0.76 and 6.54 percent for calibration and 0.87 and 4.74 percent for validation period, respectively, to evaluate model performance. Changes in land use, as well as the amount of precipitation, have a big impact on stream discharge. Agricultural land (corn, orchard, and tea) increases by 9782.67 ha (2.45 percent) over the baseline scenario, whereas woodland (forest-mixed) drops by 1091.77 ha (2.75 percent ). Furthermore, precipitation increases 3.74 percent in the mean wet season but decreases 0.5 percent in the mean dry season when compared to the baseline period. The SWAT model was able to successfully simulate stream discharge and sediment output for the Nghinh Tuong watershed not only for the Baseline scenario, but also for Scenario 1. SWAT shows its capacity to replicate stream discharge at the subwatershed level in a nutshell. It’s a great tool for dealing with water quantity and quality management in the Nghinh Tuong watershed. According to this study, SWAT is an excellent strategy for resource and environmental management.
Phan Dinh Binh
Faculty of Resources Management, Thai Nguyen University of Agriculture and Forestry, Viet Nam.