Ecological Operation Objectives for Four Major Chinese Carps Spawning in the Xijiang River

Donghui Wan,Xinghua Ma,Hehai Xie,Yunyun Shi,Fang Yang,X Lei,S Cai,Y Yu,H Li

doi:10.1051/matecconf/201824601067

Abstract

The river basin cascade development has prominent influence on water ecology for breeding of four major Chinese carps, and the determination of ecological operation objectives is an important basic work to carry out the ecological operation. This study determines the main control indexes of reservoir operation by analysing the relationships between larval population of Xijiang Dongta spawning ground and impact indexes like water temperature, flood process and flow velocity. Taking peak flow, initial discharge, flow rising range, daily increasing rate of flow and duration of water level rising of the spawning ground as the control indexes, the target flow process of reservoir ecological operation can be determined. Furthermore, the drifting velocity of fish eggs is used as the test index to control the section flow in the scheduling river reach. The proposed method is applied to the ecological operation of Dongta spawning ground, and the target flow processes of ecological operation under low, medium and high flow levels are obtained.

Highlights

For the development and utilization of water resources, a large number of reservoir dams are built in China
Because fish only spawning when water temperature (T) of the spawning ground is above a certain value, and water temperature of the spawning ground can hardly change from reservoir operation, so T should not be regarded as an index of ecological operation and should be a key constraint factor in timing of ecological operation
The control indexes of the target flow process of reservoir ecological operation are identified by summarizing the previous studies and analyzing the relationships between the spawning of four major Chinese carps and the main ecological-hydrological indexes in Xijiang Dongta spawning ground

Summary

Introduction

For the development and utilization of water resources, a large number of reservoir dams are built in China. These projects played an important role on flood control, power generation, water supply, irrigation and navigation, and effectively promoted the economic and social development, and caused remarkable influences on watershed hydrological regime and river ecosystem [1]. Change in natural hydrological conditions caused by development and utilization of water resources like damming and water diversion is considered to be one of the main causes of river ecological problems [2].

Appropriate water temperature

Appropriate flow velocity

Control indexes for reservoir ecological operation

Target flow process of the spawning ground

Conclusions