Abstract:  Based on the long data sequences of precipitation, runoff and sediment from 1960 to 2002 in the Dalihe River Basin, the year of 1969 was regarded as a delimitation year, before which the watershed was considered as in its natural state, otherwise harnessing state. According to the geomorphic types, the underlying surface and hydrological station network, the basin was divided into three districts: the respective upper reaches of Qingyangcha Station, Lijiahe Station and Suide Station. The empirical equations in flood season between rainfall and runoff, rainfall and sediment, and runoff and sediment before the delimitation year of each district were established. The calculated values from the empirical equations were compared with the measured values to analyze the influence of human activities on the variation of runoff and sediment in the Dalihe River Basin.

Key words: the Loess Plateau  ,   Dalihe River  ,  variation of runoff and sediment