Runoff Variation of Zhuanglang River and Its Ecological Effect under Influence of Human Activities

To explore the influence of human activities on the runoff ecosystem in the Zhuanglang River, the runoff changes in the Zhuanglang River and its runoff ecosystem from 1970 to 2020 were studied using the ecological runoff index based on the flow duration curve (FDC). The results are as follows. ①After hydrological variation, the runoff changes of the Zhuanglang River are different at upstream and downstream stations. The average value and rate of change of the runoff are significantly decreased at upstream stations but increased at downstream ones. ② Intensive human activities are the main reason for the runoff variation of the Zhuanglang River. The rise of agricultural water consumption in the upstream areas leads to a drop in river runoff, with its negative effect exceeding the positive one of climate humidification on an annual scale. However, to increase the annual runoff, the ecological water replenishment project of Datong River to Qinwangchuan Region Diversion is introduced in the downstream river, of which the contribution rate is 97.1%, while the contribution rate of precipitation change is only 2.9%. ③ After hydrological variation, a slight lack of ecological water demand is seen in the upstream river and is gradually improved under climatic humidification. The health of the runoff ecosystem in the downstream river is significantly enhanced, with <italic>EI </italic>(integrated runoff ecological index) up to 2. This provides data support for the strong impact of human activities on the health of the river runoff ecosystem and the high-quality and sustainable development of the Yellow River basin under the condition of continuous warm and humid climate.