A new method for calculating ecological flow: Distribution flow method

Guangming Tan,Yiwei Lyu,Zhi Yin,Caiwen Shu,Ran Yi,Zhiyong Feng,Jianbo Chang,Shasha Han

doi:10.1063/1.5022048

Guangming Tan, Yiwei Lyu + Show 6 more

Open Access

https://doi.org/10.1063/1.5022048

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Abstract

A distribution flow method (DFM) and its ecological flow index and evaluation grade standard are proposed to study the ecological flow of rivers based on broadening kernel density estimation. The proposed DFM and its ecological flow index and evaluation grade standard are applied into the calculation of ecological flow in the middle reaches of the Yangtze River and compared with traditional calculation method of hydrological ecological flow, method of flow evaluation, and calculation result of fish ecological flow. Results show that the DFM considers the intra- and inter-annual variations in natural runoff, thereby reducing the influence of extreme flow and uneven flow distributions during the year. This method also satisfies the actual runoff demand of river ecosystems, demonstrates superiority over the traditional hydrological methods, and shows a high space–time applicability and application value.

Highlights

The hydrological regime of rivers is mainly influenced by climate and intensive human activities, and such influence, which is primarily manifested in runoff variations, threatens and even destroys the health of river ecosystems.[1,2] The ecological water demand of rivers under hydrological variations must be investigated to maintain their healthy development
Traditional hydrological method considers percentage of annual average runoff, guarantee rate (GR) of natural runoff frequency curve, or exceeding frequency on flow duration curves and calculates ecological water demand and evaluation grade; these methods are known for their high subjectivity, experience requirements, and regional limitations.[15,16,17]
This study investigates the ecological water demand in the middle reaches of the Yangtze River based on daily runoff before and after variation

Summary

Introduction

The hydrological regime of rivers is mainly influenced by climate and intensive human activities, and such influence, which is primarily manifested in runoff variations, threatens and even destroys the health of river ecosystems.[1,2] The ecological water demand of rivers under hydrological variations must be investigated to maintain their healthy development. Traditional hydrological method considers percentage of annual average runoff, guarantee rate (GR) of natural runoff frequency curve, or exceeding frequency on flow duration curves and calculates ecological water demand and evaluation grade; these methods are known for their high subjectivity, experience requirements, and regional limitations.[15,16,17]

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Conclusion