An Assessment of Ice Effects on Indices for Hydrological Alteration in Flow Regimes

Changes in the flow regime of the Yangtze River were investigated using an efficient framework that combined the eco-flow metrics (ecosurplus and ecodeficit) and Indicators of Hydrologic Alteration (IHA) metrics. A distributed hydrological model was used to simulate the natural flow regime and quantitatively separate the impacts of reservoir operation and climate variation on flow regime changes. The results showed that the flow regime changed significantly between the pre-dam and post-dam periods in the main channel and major tributaries. Autumn streamflow significantly decreased in the main channel and in the tributaries of the upper Yangtze River, as a result of a precipitation decrease and reservoir water storage. The release of water from reservoirs to support flood regulation resulted in a significant increase in winter streamflow in the main channel and in the Minjiang, Wujiang, and Hanjiang tributaries. Reservoir operation and climate variation caused a significant reduction in low flow pulse duration in the middle reach of the Yangtze River. Reservoir operation also led to an increase in the frequency of low flow pulses, an increase in the frequency of flow variation and a decrease in the rate of rising flow in most of the tributaries. An earlier annual minimum flow date was detected in the middle and lower reaches of the Yangtze River due to reservoir operation. This study provides a methodology that can be implemented to assess flow regime changes caused by dam construction in other large catchments.

Section: Comparison With Recent Similar Studiesmentioning

confidence: 99%

Section: Comparison With Recent Similar Studiesmentioning

confidence: 99%

Analyzing Changes in the Flow Regime of the Yangtze River Using the Eco-Flow Metrics and IHA Metrics

Gao

Wang

2018

“…Warner [12] explored the environmental impacts of hydroelectric power and other human activities on the Durance channel in Southeast France and found that the flow diversion caused by a hydropower development has resulted in the shrinkage of the channel and reduction in habitat. Meißner et al [13] compared the water temperature, discharge, and macroinvertebrate samples to determine a means of mitigating the negative impact of the hydrological alterations resulted from downstream dams in Germany, while Alfredsen [14] used IHA to assess the effect of ice on river flow in Norway. Yuichiro et al [15] analyzed the impacts of dam operation on the water discharge and capture fisheries in the lower Mekong basin in Southeast Asia.…”

Section: Introductionmentioning

confidence: 99%

Reservoir-Induced Hydrological Alterations Using Ecologically Related Hydrologic Metrics: Case Study in the Beijiang River, China

Wang

et al. 2020

Anthropogenic activities have a tremendous impact on water ecosystems worldwide, especially in China. To quantitatively evaluate the hydrological alteration connected with aquatic lives and river ecological risks, we took the Beijiang River located in South China as the case study and used ecosurplus (defined as ecological carrying capacity exceeding ecological consumption)/ecodeficit (defined as ecological consumption exceeding carrying capacity) and Indicators of Hydrological Alterations to evaluate hydrological changes. The Ecologically Relevant Hydrologic Indicators were employed to select the key indices of Indicators of Hydrological Alterations, and the eco-environmental water demand calculation provide an effective way for the reservoir operation. Results showed that: (1) High flows contributed more to the ecodeficit, while low flows contributed more to the ecosurplus; (2) the ecodeficit in some parts of the river basin might exceed the ecosurplus after reservoir construction, especially along the main stream; and (3) the determination of eco-environmental water demand is a feasible way for improving the environment by controlling reservoirs. The current study can help guide the optimization of hydrological operation in the basin toward making the ecosystem healthier and has potential to further provide a reference for other basins in terms of hydrological alterations driven by anthropogenic activities.

“…A precursor for understanding change within ice-covered rivers is characterization of its flow and ice regime. Alfredsen [34] investigated the effects of ice on the flow conditions of rivers in relation to their hydrological variability during winter. He used the index of hydrological alteration (IHA) to characterize the interaction between the rivers' flow and ice regimes.…”

Section: Physical Processes and Ice Phenologymentioning

confidence: 99%

River and Lake Ice Processes—Impacts of Freshwater Ice on Aquatic Ecosystems in a Changing Globe

Baulch

Cavaliere

2018

This special issue focuses on the effects of ice cover on surface water bodies, specifically rivers and lakes. Background information on the motivation of addressing this topic is first introduced with some selected references highlighting key points in this research field. A summary and synthesis of the eleven contributions is then provided, focusing on three aspects that provide the structure of the special issue: Physical processes, water quality, and sustainability. We have placed these contributions in the broader context of the field and identified selected knowledge gaps which impede our ability both to understand current conditions, and to understand the likely consequences of changing winters to the diversity of freshwater ecosystems subject to seasonal ice cover.