Research On Early-warning And Forecasting System Of Small Watershed Mountain Torrent Disasters

Duiziqian watershed on Suichuan county is one of the most typical prone areas ofmountain torrent disasters in Jiangxi province. The mountain torrent disasters thatoccurred almost every year seriously endangering people′s lives and propertiesand national economy. Therefore, on the basis of critical rainfall value and the riskassessment put forward the mountain torrent disaster early warning and forecast in smallwatershed.Analyse the characteristics and causes of the mountain torrent disasters based on thetypical small watershed natural geography, hydrology and meteorology, topography andgeology, the ecological environment and the survey data of mountain torrent disaster.Adopted the analysis study of single station threshold rainfall and dynamic criticalprecipitation for the calculation of critical rainfall on mountain flood disasters, alsoadvanced critical rainfall as an important indicator of disaster warning forecast todetermine the early warning index.Meanwhile, according to two aspects as the degree of disaster-prone and riskassessment to conduct the risk assessment of the watershed.The risk level of the studyarea is determined by the two major indicators as the degree of vulnerability andrisk.And mainly analyzed the rainfall that one of the disaster-causing factors in the riskanalysis part. Rainfall risk zoning has been Put forward under different soil saturationcombined with the critical rainfall. Analytic hierarchy process (AHP) is adopted toconfirm the weight of all factors in the vulnerability analysis. And The degree of riskevaluation index using experts analysis. Ultimately, determine the risk degree ofDuiziqian Watershed.This article obtained critical rainfall values of lh,3h,6h,12h,24h by means of singlestation were30mm,53mm,70mm,85mm and118mm; The relation curve of criticalrainfall under different saturation has been getting through dynamic critical rainfall method;According the degree of risk is0.51,Duiziqian basin has been determined to the high riskarea where the risk index is0.936and vulnerability degree index is0.55.Finally, mountain torrent disaster early warning forecast method in small watershed isput forward by the combination of rainfall and risk evaluation. The rainfall is divided intodifferent risk level in the base of the critical rainfall. By superposition with risk grade, thisbasin is carved out of five warning levels and divided into three warning state that theyellow warning, orange alert and red alert, and is verified in duiziqian river basin.