Analysis of an Ecological Flow Regime during the Ctenopharyngodon Idella Spawning Period Based on Reservoir Operations

Jie Li,Shaoqian Pei,Wei Wen,Liqiang Yao,Hui Qin,Liang Yi,Jianzhong Zhou,Lingyun Tang

doi:10.3390/w11102034

Jie Li, Shaoqian Pei + Show 6 more

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https://doi.org/10.3390/w11102034

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Abstract

The study of fish habitats is important for us to better understand the impact of reservoir construction on river ecosystems. Many habitat models have been developed in the past few decades. In this study, a fuzzy logic-based habitat model, which couples fuzzy inference system, two-dimensional laterally averaged hydrodynamic model, and two-dimensional shallow water hydrodynamic model, is proposed to identify the baseline condition of suitable habitat for fish spawning activities. The proposed model considers the reservoir and the downstream river channel, and explores the comprehensive effects of water temperature, velocity, and water depth on habitat suitability. A real-world case that considers the Ctenopharyngodon idella in the Xuanwei Reservoir of Qingshui River is studied to investigate the effect of in- and outflow of reservoir on fish habitat and the best integrative management measure of the model. There were 64 simulations with different reservoir in- and outflows employed to calculate the weighted usable area and hydraulic habitat suitability. The experimental results show that the ecological flow for Ctenopharyngodon idella spawning can satisfy the basic demand when the reservoir inflow is greater than 60 m3/s and the reservoir outflow is greater than 100 m3/s. The habitat ecological suitability is the best when the reservoir outflow is 120 m3/s. A more reasonable and reliable ecological flow range can be obtained based on the habitat model in this paper, which provides the best scenario for water resources planning and management in the Qingshui River Basin.

Highlights

Reservoirs play key roles in the social and economic development as a water conservancy project that prevents or controls flood and regulates water flow [1], the construction of a reservoir changes natural flow regimes of a river and has an impact on the river
The Xuanwei Reservoir has thermal stratification, and it is necessary to analyze the negative effect on the C. idella spawning in downstream of the reservoir caused by the releasing of water with low temperature
The results show that when velocity and water depth are excessively large or small, habitat suitability is so poor that the hydraulic condition cannot meet the spawning requirements of C. idella

Summary

Introduction

Reservoirs play key roles in the social and economic development as a water conservancy project that prevents or controls flood and regulates water flow [1], the construction of a reservoir changes natural flow regimes of a river and has an impact on the river. These effects are mainly manifested as follows: (1) blocking the migration path of fish to make it impossible to complete its life history process, resulting in a decline in genetic diversity of fish populations [2]; (2) affecting sediment transport, resulting in sedimentation at the bottom of the reservoir and river blockage [3];. Hydropower is attracting more and more attention as a clean and sustainable energy source

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