Abstract: The upstream of Yachihe Hydrologic Station is the main sediment area in Wujiang River Basin. The sediment movement to the downstream has important influence on sediment status in the whole basin. The characteristics of rainfall, runoff, sediment yield, and sediment transport have greatly changed since 1959. Based on longterm hydrology data, we analyzed the characteristics of runoff and sediment variation in the Yachihe River Basin and summarized the causes of such changes. The results showed that there was no significant variation in rainfall, but runoff showed a significant downward trend. In general, the sediment quantity was positively correlated with runoff quantity. However, there were great changes in sediment quantity of Yachihe Hydrologic Station and HongjiaduHydrologic Station after 1994 and 2004, respectively. The sediment quantity of Yachihe Hydrologic Station was reduced by 98.8%, and that of Hongjiadu Hydrologic Station was close to zero. The variation of runoff was mainly caused by human activities. Especially, the sudden change of runoff in 2002 was closely related to the construction of HongjiaduHydropower Station. The change of sediment yield was mainly caused by the change of the underlying surface due to human activities, whereas sediment transport was mainly blocked by dams in the river. Sediment deposition amount in cascade reservoirs was about 261.4 million tons between 1994 and 2014, and that in Hongjiadu Reservoir was about 33.8 million tons between 2004 and 2014.

Key words: climate change, spatial pattern, Elaeagnus mollis, Maxent, migration tend