12. ASSESSMENT OF IMPACTS OF LAND USE ON THE FLOW OF VU GIA - THU BON RIVER BASIN

Tóm tắt

Water resources in the Vu Gia - Thu Bon river basin are under pressure due to population growth, socio-economic development, the impact of climate change, and land use change, which is also considered one factor that changes flow regimes in river basins. Therefore, the study “Assessing the impact of land use on the flow regime in the Vu Gia - Thu Bon river basin” is vital and urgent. This study utilized the GIS-based Soil and Water Assessment Tool (SWAT) model to simulate the flow of Vu Gia - Thu Bon river basin at two hydrological stations - Nong Son and Thanh My, during the calibration period (2004 - 2010) and the verification period (2011 - 2015). The evaluation results of both periods, as measured by the NSE and R2 indexes, were found to be above 0.75. Additionally, the study assessed the impact of land use on the flow regime based on two land use scenarios: One for 2015 and another for 2020, with the evaluation period spanning from 2004 to 2018. The study results showed that groundwater flow tends to decrease, while surface runoff tends to increase due to changes in land use. The forest land area in the basin, which accounts for over 93 % of the total land, only decreased by 1 %, while urban land area increased from 0.95 % to 1.53 %, and vacant land area increased from 1.58 % to nearly 3 %. However, the flow in the whole basin was generally not significantly affected.