RESUMEN
Precipitation and vegetation are two key factors affecting floods in the watershed. Quantitative evaluating their contribution to flood is of great scientific significance to vegetation construction and water resources management. Based on the geographic information data and hydrometeorological data from 1983 to 2014, we analyzed the characteristics of rainstorm and flood in Pengchongjian small watershed in red soil region of South China by Mann-Kendall test method, cumulative anomaly method and HEC-HMS model, and quantitatively evaluated the contribution rate of precipitation and vegetation variation to flood. The results showed that the rainstorm volume and total flood volume in Pengchongjian small watershed from 1983 to 2014 showed a non-significant upward/downward trend, respectively. HEC-HMS model had good simulation effect on single rainstorm flood, with the evaluation results being within the error range. The contribution rates of precipitation and vegetation variation of different rainstorm floods were different with respect to the total flood volume or to the peak flow. The average contribution rate of precipitation and vegetation variation to the total flood volume was 66.5% and 33.5%, while to the peak flow was 58.9% and 41.1%, respectively. Our results could provide scientific basis for flood evaluation, vegetation construction and comprehensive control of soil erosion in small watershed.