5. Conclusions
In this paper, three rainfall regimes were classified from 152 events
using K-means clustering based on rainfall depth, max-30 min intensity
and duration. Rainfall Regime I causes the greatest proportion of accumulated
runoff and soil loss. The values of the mean runoff coefficient
and the mean sediment load of the different rainfall regimes were
as follows: Rainfall Regime II> Rainfall Regime I> Rainfall Regime
III. A shift from paddy fields and cropland to forest and orchards in
the Wangjiaqiao watershed is the most important land use change
between the years 1995 and 2004. The results indicated that the runoff
and soil losses of different land uses (land uses before and after 2000)
varied greatly under the different rainfall regimes. Apparently, the overall
impact of the land use changes in the study period was considerably
decreased runoff and soil loss in the Wangjiaqiao watershed. The different
rainfall regimes are decisive for the sensitivity of this decrease. Runoff
caused by the storms of large rainfall depths, mainly under Rainfall
Regimes I and II, are more strongly influenced by land surface conditions
than floods caused by precipitation with lower rainfall depths.