05. Quantification of surface water balance components of Day river basin by SWAT model

Abstract

This study aims to quantify the main components in the water balance in order to determine the proportion of each component's contribution to the potential water resource in the Day river basin from Van Coc dam to after Bui tributary. This will serve as a basis for selecting and allocating water sources in a rational and sustainable way. The SWAT model was used and set up with 20 sub-basins, 4 calculation areas, 4 large reservoirs, and 1 Cam Dinh sluice in the form of Point Score. Using SUFI-2 technique to calibrate and verify the model at Lam Son and Ba Tha stations showed good results, ensuring for the simulation of the whole basin. The model results used to quantify the main components in the water balance includes precipitation (P), evaporation (E), surface water volume (SURQ), river water infiltration into aquifers (SWGW) and groundwater discharge into river (GWQ). The results from the model showed that in the studied basin, the flow generated from rain accounts for 63.44%; the water transferred from the Red River into the basin through Cam Dinh sluice accounts for 36.54%; the amount of groundwater discharging to river accounts for 0.02%; and the river water infiltrating into aquifers accounts for 1.1%.