| Ningxia is located in the hinterland of northwest China.The mountainous and gully area occupies 2/3 of the whole area.The special geographical environment and hydrological conditions cause the mountain torrent disaster frequently in Ningxia,which seriously threaten people's life and property,especially the economic and social sustainable development of Ningxia.In order to solve the problem that the monitoring and early warning indicators are difficult to be accurately quantified in Ningxia mountain torrent disaster prevention and control,based on the status quo of mountain flood disaster prevention and control in Ningxia,this paper systematically carries out the calculation and intelligent prediction research of Ningxia mountain torrential disaster monitoring and early warning indicators.The main contents are as follows:(1)Based on the comprehensive analysis of hydrological and meteorological,geological features,characteristics of storms and floods,cause of flash floods and the characteristics of disaster,the flood disaster areas of Ningxia were classified.Based on the four factors,rainfall distribution,topographic features,administrative boundaries and underlying surface types were selected as the basis of division.Based on the analysis and plotting of the rainfall zoning map,topography and geomorphology zoning map,the administrative zoning map and the underlying surface zoning map,after comparison and optimization,the whole area of Ningxia is divided into 16 mountain flood disaster zoning.(2)Based on the characteristics of flood disaster in Ningxia,the characteristics of flood disaster,the actual demand of flood prevention for early warning of mountain flood disaster,the critical rainfall were chosen as the indicator of mountain flood disaster monitoring and warning in Ningxia.The critical rainfall analysis level and calculation duration were determined.P-? frequency curves,the thresholds of critical rainfall monitoring and warning indicators for different periods in different periods of different regionalization were calculated.(3)Taking the Kushui River Basin as a typical river basin,the design flood process corresponding to the reappearing period is deduced from the 50-year and 100-year monitoring and warning rainfall thresholds in the Kushui River Basin.The Kushui River and the one or two dynamic flooding coupled numerical model to simulate the flood overflow movement and its two-dimensional plane in the two-dimensional region of the evolution process,the statistical analysis of the impact of cross-strait regional disaster situation.(4)Based on BP artificial neural network,an intelligent forecasting model for mapping the complex relationship between disaster,water regime and rainfall in the Kushui River Basin was established.The different disaster characteristics were predicted scientifically based on the water depth of the flooded and the corresponding overflow flow.And hydrological statistical results were compared with the mutual authentication.The results show that the relative error of model prediction is less than 5%,and the analytical precision is high,which can reflect the extremely complex nonlinear relationship between disaster distribution,river discharge and rainfall.This paper divides the division of mountain flood disaster in Ningxia,analyzed the rainfall monitoring and early warning indicators and the flood warning and disaster impact of the Zishui River basin,and established the intelligent forecasting model of precipitation in the Kushui River Basin based on BP artificial neural network.It provides a critical rainfall a new method of forecasting.The results of this paper can provide some technical support for monitoring and early warning of mountain torrents disaster in Ningxia. |
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