Evaluation of river hydrological regime changes under the influence of Gangkouwan Reservoir

The construction of the reservoir has met human needs to a certain extent, but it has caused serious threats to river ecosystems, especially for the hydrological regime. In order to deepen the understanding of the impact of the reservoir, this paper introduces the Indicators of Hydrologic Alteration (IHA) method, constructs an indicator system that describes the changes in hydrological regime, and uses the Range of Variability Approach (RVA) to quantitatively evaluate the changes of 5 groups of 33 indexes after the construction of Gangkouwan Reservoir, thus realizing the quantitative change of the river hydrological regime. The results show that the Gangkouwan Reservoir affects the frequency and duration of high and low pulses highly, as well as in rate and frequency of water condition changes, and the integral change degree of hydrological regime is moderate.