Coupling duo-assimilation to hydrological model to enhance flood forecasting

Abstract

Model parameters play important roles in the accuracy of model results, especially parameters characterizing initial states of the basin need to be updated regularly with the most recent ground station data. This study applied ensemble the Kalman filter (EnKF) coupled with the HYdrological MODel (HyMOD) hydrological model to identify the optimal parameterization for flood forecasting and provided assessments of its impacts on the Chu River Basin of Vietnam. The results showed significant improvements with the application of EnKF techniques, however the parameterization depends on types and characteristics of flood events. The parameters were converged by the end of the simulated time periods to the most accurate model parameterization. As a result, the Nash–Sutciffe coefficient was 0.9 for EnKF, whereas it was only 0.3 for non-EnKF; mean absolute bias of 70 m³/s in applied-EnKF compared with 400 m³/s in non-EnKF, the Brier Score and spread values in applied-EnKF are much closer to zero than that in non-EnKF.

Keywords:

• assimilation
• duo-assimilation
• flood forecast
• Ma-Chu river
• EnKF

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was funded by the Ministry of Science and Technology of Vietnam under the project [code: NÐT.58.RU/19], and sub-project of Fostering Innovation through Research, Science and Technology (FIRST) [code: 08/FIRST/2a/CEFD].

Notes on contributors

Dinh Duc Dang

Dinh Duc Dang, holding bachelor’s and master’s degree in Hydrology, is currently the chief of Research and Service Division at the Center for Environmental Fluid Dynamics, VNU-University of Science (CEFD-VNU-HUS). He has over 10 years experiences working on the field of urban and river hydrology, hydraulics, and flood forecasting. He has conducted many research and projects in water-related problems such as flood, drought, salinity intrusion etc. He is now doing his Ph.D. research on improving the quality of flood forecasting at VNU University of Science, Vietnam National University, Vietnam.

Tran Ngoc Anh

Tran Ngoc Anh is the director of CEFD-VNU-HUS. He is also a professor in the field of hydrodynamic modelling and water resource management at the Faculty of Hydrology, Meteorology and Oceanography, VNU University of Science, Vietnam National University, Hanoi, Vietnam. He has more than 20 years working experience in a number of research and projects funded by national and international institutes in the water-related field.