Abstract:

Rainfall erosivity is an important factor for soil loss estimation,yet how to estimate rainfall erosivity in regions with limited rainfall information is critical for water and soil conservation.In this study,several empirical models were used to estimate rainfall erosivity based on daily rainfall data from 4 meteorological stations in the Danjiangkou Reservoir region,i.e.Danjiangkou，Shiyan，Yunxi and Yunxian of Hubei Province.By comparing the estimated results with existing research results,one of the best performed models was selected for regional rainfall erosivity computation.The average rainfall erosivity is 3 331.94,3 272.40,3 501.21,3 187.94 MJ·mm/hm²·h·a for Danjiangkou,Yunxi,Shiyan and Yunxian,respectively.The estimated rainfall erosivity shows homogeneous distribution cross the reservoir region.The rainfall erosivity concentrates in May to September,comprising more than 8860% of its annual value.The single rainfall erosivity has large variability,especially for Yunxi and Shiyan where the maximal single rainfall erosivity accounts for 6.94% and 4.87% of the total rainfall erosivity respectively.The coefficient of change trend r(ranging from 0.45 to 0.58)and the coefficient of variation Cv(ranging from 005 to 008)indicate that the rainfall erosivity has been relatively stable in the past half a century in the reservoir region.

Key words: rainfall erosivity/Danjiangkou Reservoir/daily precipitation