Relationship between rainfall erosivity indicators under arid environments: Case of Liudaogou basin in Chinese Loess Plateau

Soil water erosion is a well known cause of land degradation in the Chinese Loess Plateau. Many of its rivers, such as Yellow River are known to carry huge sediment loads. For proper management of sediment laden rivers, it is essential to identify those catchments which have high erosion potential. Such an assessment may be effectively used in watershed treatment to mitigate the effects of sediment erosion and is currently facilitated by a series of erosion indices. Rainfall erosivity is one of the major factors that control soil erosion in Loess Plateau, China. Several indices have been developed to quantify the rainfall erosivity; however, none of them was specifically developed for arid environments. In this study we examined the performance of several indices with different temporal-resolution of the required rainfall data inputs. Rainfall data were measured with 0.5 second logging interval in Liudaogou basin, Loess Plateau China. The monthly, daily, and 15-minute rainfall data were used to calculate the Fournier Index (IF), half month erosivity index (M-i), and monthly erosivity index (EI30). The relationship between the examined erosivity indices and monthly rainfall depth (P-i) was observed to be statistically significant. Power relationships between the EI30 and FI were able to represent the EI30 significantly (R-2 = 0.77, P< 0.001). However, the results also showed that the relationships are not suited to the intensified rainfall storms.