Human-Induced Runoff Change in Northeast China

Human activities are known to increase interference with runoff. Conversely, human activities related to utilizing and managing water resources are primarily determined by annual runoff processes dominated by precipitation distribution. With this view, the soil and water assessment tool was used to quantify human-induced annual runoff changes at different periods and under different patterns of precipitation in seven catchments in Northeast China. The conclusions are as follows. First, although human activities have distinct regional characteristics, an increase in reduced runoff is found for the catchments under investigation; human-induced runoff changes are more significant in the catchment where water resources are limited. Second, the interannual runoff distribution is significantly disturbed in the catchment with large reservoirs. Third, human-induced runoff changes are similar under all patterns of precipitation in the catchment where annual precipitation is less than 500mm and intense human activities play a dominant role in runoff. Fourth, in general catchments, runoff changes more significantly during relatively drier years or years with uneven precipitation distribution. Finally, human-induced runoff change is related to both annual precipitation characteristics and operations of the reservoirs for catchments in which reservoirs played a significant role.