The Research on the Flood Disaster of Guanzhong in Song Dynasty

Through the collection and analysis to the historical materials,the temporal and spatial characteristics,the disaster ranks and the disaster origins of the flood disaster in Song Dynasty in Guanzhong Plain were studied in this paper.The results showed that flood disaster in the Song Dynasty altogether had 34 times from 960 to 1279,and averagely occurred one time per 9.38 years.The disaster frequency distributions were unequally and having notable stage,but the memorial came down as a whole trend in intermediate stage.Compared with other dynasty,the flood disasters were fewer in Song Dynasty.The main reason was draught climate.The disaster occurrence concentrated in Summer and Autumn.On the space distribution,the falling order was Bao Ji City,Xi'an,Xian Yang City,Wei Nan City,Tong Chuan;flood disaster in Song Dynasty was sivided into four levels in small,middle,big,especially big in Guanzhong Plain;The occurrence probability was 18.5%,40.8%,25.9%,14.8% respectively.