CALCULATING THE INFLOW TO TUYEN QUANG RESERVOIR BY HEC-HMS MODEL USING DIFFERENT LULC MAPS AND BASIN DIVISIONS

For mathematical models in general and hydrological models in particular, the accuracy of input data and the detail in using that data greatly affect the calculation results. For each specific requirement, how detailed the input data needed to ensure the accuracy while still meeting the requirements of real-time tasks is an issue that needs to be surveyed and researched. In this paper, the authors use HEC-HMS model with two types of LULC (Land use-Land cover) maps and different ratios of basin division to calculate Tuyen Quang reservoir inflow for August 2023 and July 2024 floods. The results show that the Jaxa LULC map gives better results than the Microsoft and Esri LULC map and divides Tuyen Quang basin into 29 sub-basins is more suitable than 09 and 49 sub-basins. From there, the influence of LULC map as well as the ratio of basin division on the accuracy and calculation time are commented.