for 12 h, after which they were weighed. Finally, the sediment concentration and the modes of sediment transport by runoff were calculated.
3. Results and discussion
3.1. Rainfall characteristics
There were three types of rainfall events from 1999 to 2000 in the Xujiawan, Kunniushan and Sangshutu agro-watersheds; ML- type rainfall, in which high intensity rainfall appeared in the middle of the event, IM-type rainfall, which was characterized by discontinuous rainfall with obvious segments throughout the rainfall event, and PP-type rainfall, in which there was high