Evaluation of hydrological regime alteration and ecological flow processes in the changing environment of the Jialing River, China

Abstract

Ecological flow is a key element in maintaining the biodiversity of a basin's aquatic ecosystem. This study quantifies the degree of hydrological regime alteration in the Jialing River and the contributions of various driving factors using the indicators of hydrologic alteration and range of variability approach (IHA-RVA), the river impact method (RI), and the elasticity coefficient method based on long-term hydro-meteorological data. Cross-wavelet analysis is used to reveal the periodicity and coherence of runoff and driving factors. Additionally, the improved Q90 method presents a more effective annual ecological flow process. The results show that the overall hydrological regime in the Jialing River has undergone a moderate change, with RVA and RI values of 45.02% and 0.66. Human activities contribute 54.68% to the changes in streamflow. Streamflow has an extremely significant correlation with precipitation and aridity index (Φ). Approximately 85% of the wavelet cone of influence (COI) area, tested at a 95% confidence level, falls within the region. The study also found that the ecological flow obtained through the improved Q90 method is more conducive to the healthy development of the river ecosystem in the Jialing River. These findings can provide some assistance for aquatic ecosystem restoration in the Jialing River.

How does the daily regulation hydropower station reduce the hydrological regime impact? A case study in upper Yellow River

“…When incorporating the operation of daily regulation at hydropower stations, the maximum flow notably increases, while the variation is reduced by approximately 40% compared to the results observed between the P1 and P3 periods. The occurrence of high-flow events enhances the connectivity between the floodplain and the main channel, playing a crucial role in delivering nutrients to wetlands and providing fish and other mobile organisms with increased opportunities to move through rivers into floodplains for breeding or into shallower habitats (Xie 2003;Arthington et al 2010;Guo et al 2024). As for the minimum flow statistics, a positive relationship is evident between the extent of change and the timescale, consistent for both the P2 and P3 periods.…”