Spatial And Temporal Distribution And Causes Analysis Of Slope Collapse Erosion In Youtian Town Of Wuhua County

Guangdong Province is the most eroded area in the red soil region of southern China.The erosion degree of Wuhua County is ranked first in Guangdong Province and it is a typical area of collapse.This paper chose the Youtian town of Wuhua County as the research object,and collected the topographic maps of 1978 and 1995 and the data of investigation of collapse hill in 2005,by the means of ArcGIS,RDA analysis and artificial processing.It studied the law of the spatial and temporal distribution of collapse and the influencing factors of collapse distribution.The results are as follows:(1)In 1978~2005,The performance of slope collapse of Youtian town was the first to decrease and then increase sharply from 1978 to 2005,and the overall increased respectively is 380%,632% and 494%,and the erosion modulus was 30489.4 t/(km2?a),equivalent to annual erosion of the ground 22.6 mm,belonging to the scope of severe erosion.From the size of the collapse to see,it changed from mainly of the medium and large collapse to mainly of large-scale.(2)The law of the spatial distribution of collapse: the collapse of Youtian town mainly concentrated in the southwest region of Wanhua village,Xiatao village and Yangkeng village.It is showing the diminished distribution characteristics of decrease from the southwest to the northeast.Most of the collapsing hill developed at altitude of 100~300 m,the relative height of 0~60 m,slope of 15°~35° steep slope,the sunny slope aspect of highland area.The distribution laws of altitude,relative height and slope are increasing firstly and then decreasing,and the rate of sunny slope to shady slope is about 3:1.(3)The change rule of collapse with time: Between 1978 and 2005,there are small differences in the spatial distribution of slope collapse in different years,but the overall distribution is consistent.with the change of time.From the perspective of individual indicators,the changes of the distribution of administrative area,height distribution,slope distribution and slope aspect distribution were complex and varied.The change of the different type distribution is basically the same as the change of the erosion status in this period.It is relatively gentle in the early period(1978~1995)and rapidly change in the late period(1995~2005).(4)The relative height play a major role to single slope collapse,the highest elevation,weighted slope have important effects on the slope collapse distribution.Effects of slope aspect,minimum elevation and other factors are low on the slope collapse distribution.(5)Slope,slope aspect,elevation and other geomorphological factors play a major role in the distribution of regional collapse,economic?social factors and vegetation factors for its performance as a supporting role.