Characteristics and Practices of Ecological Flow in Rivers with Flow Reductions Due to Water Storage and Hydropower Projects in China

Lejun Ma,Changjun Qi,Xingnan Zhang,Huan Wang

doi:10.3390/w10081091

Abstract

Water and flow reductions in the channels downstream of water storage and hydropower projects have significant impacts on aquatic ecosystems. Understanding and analyzing the ecosystem status is of great significance to facilitate the protection of riverine ecosystems. A database was established based on the 2000–2017 environmental impact assessment (EIA) reports on water storage and hydropower projects in China, and corresponding analysis software was built based on an ArcGIS spatial analysis platform. The projects in China are mainly found in the Yangtze and Pearl River basins and in south-western China. The hydropower projects have a larger influence than the water storage projects on the flow of downstream rivers sections, and most of the hydropower projects, especially the water diversion projects, cause flow reductions in the downstream rivers. An ecological flow management mechanism in China implemented in 2006 provided a promising method to alleviate river flow reductions. However, there is still only one kind of ecological flow calculation method and few ecological flow regulation measures in use. Based on the advantages and problems of the existing ecological flow management system, this paper proposes a management scheme based on a regional-engineering calculation method. The results can facilitate decision making in ecological flow management.

Highlights

IntroductionRiver ecosystems result from a dynamic balance between the biotic (e.g., plants and animals) and abiotic (e.g., climate, topography, and hydrology) factors under natural flow
River ecosystems result from a dynamic balance between the biotic and abiotic factors under natural flow
We summarized the relationship between the construction process type and the flow reduction events in the downstream river

Summary

Introduction

River ecosystems result from a dynamic balance between the biotic (e.g., plants and animals) and abiotic (e.g., climate, topography, and hydrology) factors under natural flow. China is one of the largest countries in terms of water storage and hydropower development, and there are already approximately 100,000 reservoirs in existing rivers according to incomplete statistics. The construction of these projects has had substantial impacts on river ecosystems [1,2,3]. Research on the hydrological changes in 186 rivers that were built in the United States indicated that the water storage and hydropower projects in rivers with dams lead to homogenization of species composition and have had negative impacts on native fish diversity [4,5].

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Discussion

Conclusion