Real-time forecasting of river water level in urban based on radar rainfall: A case study in Fuzhou City.

• A real-time rolling prediction system of urban river water level is proposed. • System is based on radar rainfall and hydrological and hydrodynamic coupling model. • The real rolling prediction of review time is restored. • Detailed long series analysis and case analysis. Urban river network plays an important role in the process of drainage. The real-time prediction system of river water level can provide early warning information to the decision-makers of relevant departments in time, which plays an important role in reducing flood risk. Aiming at the rapid and strong response of urban river to rainfall, a real-time rolling prediction system of urban river water level is proposed based on radar rainfall prediction products and coupling model of hydrology and hydrodynamics. In the system, each simulation is divided into two parts: the review period and the prediction period. In the review period, the river model is driven by the observed rainfall to obtain the latest simulation state to avoid cumulative error, while in the prediction period, the radar rainfall is used to drive in the short-term prediction of river water level. Taking Fuzhou as the research area, a long series review of the process from April 1, 2020 to October 1, 2020 was carried out. The accuracy of the river model, radar-rainfall and prediction system during the study period are evaluated and discussed in detail. The results show that the river model can simulate the process of water level change in rainfall and rain free period. The performance of radar rainfall to total rainfall prediction is better than that of process prediction. The real-time prediction system can give the water level risk according to each radar forecast rainfall process, and has good performance in judging the peak water level and peak time, which can provide reference for urban river dispatching decision-makers. [ABSTRACT FROM AUTHOR]