Automated procedure of real-time flood forecasting in Vu Gia – Thu Bon river basin, Vietnam by integrating SWAT and HEC-RAS models

• Published in: Journal of water and climate change 2019-09, Vol.10 (3), p.535-545
• Main Authors: Loi, Nguyen Kim, Liem, Nguyen Duy, Tu, Le Hoang, Hong, Nguyen Thi, Truong, Cao Duy, Tram, Vo Ngoc Quynh, Nhat, Tran Thong, Anh, Tran Ngoc, Jeong, Jaehak
• Format: Article
• Language: English
• Subjects: Climate change; Climate models; Computational fluid dynamics; Computer applications; Computer simulation; Correlation analysis; Flood control; Flood forecasting; Flood predictions; Floods; Fluid flow; Gauges; Hydraulic models; Hydraulics; Hydrologic models; Hydrologic processes; Hydrology; Rain; Rainfall runoff; Rainfall-runoff relationships; Real time; River basins; River discharge; Rivers; Runoff; Statistical correlation; Storms; Stream discharge; Stream flow; Watersheds; Weather forecasting; Weather stations
• ISSN: 2040-2244; 2408-9354
• DOI: 10.2166/wcc.2018.015

The precise and reliable simulation of hydrologic and hydraulic processes is important for efficient flood forecasting and warning. The study proposes a real-time flood forecasting system which integrates a coupled hydrological-hydraulic modeling system, weather station network, and stream gauges in a web-based visualization environment. An automated procedure was developed for linking dynamically terrestrial rainfall-runoff processes and river hydraulics by coupling the SWAT hydrological model and the HEC-RAS hydraulic model. The flood forecasting system was trialed in the Vu Gia – Thu Bon river basin, Quang Nam province, Vietnam. The results showed good statistical correlation between predicted and measured stream flow for a 10-year calibration period (R² = 0.95, NSI = 0.95, PBIAS = −1.54) and during the following 10-year validation period as well (R² = 0.93, NSI = 0.93, PBIAS = 6.18). A close-up analysis of individual storm events indicated that the magnitude and timing of peak floods were accurately predicted in 2015 (R² = 0.88, NSI = 0.69, PBIAS = 4.50) and 2016 (R² = 0.80, NSI = 0.93, PBIAS = 6.18). In addition, the automated procedure was demonstrated to be reliable with dependable computational efficiency of less than 5 minutes' processing time.