Abstract

Major floods also occur in most rivers across the country, common flood peaks exceed the alarm level 3 by 0.5 to 2 m, many rivers exceed historical flood levels, flooding is widespread, lasting for many days. Landslides took place seriously, causing great damage to people and properties, severely affecting the lives and production of millions of people in these areas. Accuracy and reliability in disaster forecasts and warnings are increasingly being improved. Hydrological, hydraulic models, flash flood warning systems, etc. use various data sources from traditional monitoring stations, automatic monitoring stations, satellite rainfall estimation data, and from numerical prediction models. However, not every phenomenon can be warned at all times, especially the phenomena of small spatial scale and short time such as heavy rain, landslides and flash floods. Especially, the river system in the northern mountainous region of our country has a complicated topography, flood events are often large and unpredictable with a multi-factorial combination. Research and application of a simulation model of flood flow regime in the river system here will help the forecasting and warning of floods have a basis and achieve higher accuracy. The results of the calibration and testing of the set of parameters for the Ngoi Thia river system show high reliability with the Nash indicator exceeding 0.8 and the peak error within the allowed range. This is the basis for applying this model to the forecasting and warning reference simulation, calculating flood inundation.