Constructing Virtual Reservoirs To Study Mountain Flood Forecasting And Early Warning Of Small Watersheds In Non-data Areas

In recent years,due to human activities,unique geomorphological characteristics,and diverse geological conditions,China's mountain torrents have occurred frequently,causing a large number of casualties.Because the distribution density of hydrological stations in small and medium rivers is low,and the necessary measured hydrological data is lacking,the traditional methods cannot carry out mountain flood disaster research,and the early warning of mountain flood disasters in data-free areas cannot be delayed.Domestic hydrological research on undocumented areas is still in its infancy.This paper comprehensively analyzes the hydrological forecasting methods in non-data areas,the watershed confluence methods in non-data areas,and the uncertainty analysis of model applications when hydrological analysis of data-free areas is carried out.Finally,the treatment methods for dealing with such uncertainties are studied.According to the characteristics of the basin in Hubei Province,this paper introduces the technology and details of the division of small watersheds,and introduces the steps of using Arc GIS to divide small watersheds and the method of remote sensing to monitor soil water content in the basin.Due to the complicated conditions of the underlying surface of the basin in Hubei Province and the uneven distribution of soil water content,the simple use of the distributed hydrological model or the super-permeability runoff model will make the net rainfall significantly smaller and the critical rainfall significantly larger,resulting in unsafe early warning.Based on this,this paper considers the net rain analysis under different soil water content scenarios using the calculation method of fullsuper-hyper filtration mixing.According to the underlying surface of the watershed and the water content of the soil,the method of super-infiltration or full filling is used to calculate the runoff.For different soil water content,the calculated flood elements are more accurate.The distribution of hydrological stations in small and medium rivers is low in density and lacks measured hydrological data.Traditional methods cannot successfully carry out research on mountain flood disasters.In this paper,the small watershed is virtualized as a reservoir model,and the process of rainfall and runoff in the basin is simulated as the process of reservoir water storage.The elevation of the reservoir in the downstream villages surveyed in the early stage of the mountain flood disaster is the base elevation of the reservoir,and the flow and discharge of the basin is the virtual reservoir.According to the amount of incoming water,the flood submerged area of the virtual reservoir is calculated according to the elevation of the downstream house,and timely warning is given to the downstream village.The hybrid model was applied in Huangpi District,Wuhan City,Hubei Province,and the results were in line with reality.It provides a new method for warning of flash floods in the area.