| 梯级开发对家鱼产卵场高低流量过程的影响 |
| Influence of Cascaded Hydropower Development on High and Low Flows in the Spawning Grounds of the Four Major Chinese Carps |
| 投稿时间：2020-11-13 修订日期：2022-05-19 |
| DOI：10.15928/j.1674-3075.202011130323 |
| 中文关键词:梯级开发 四大家鱼 产卵场 流量脉冲 水力特征 |
| 英文关键词:cascaded hydropower development the four major Chinese carps spawning ground flow pulse hydraulic characteristics |
| 基金项目:湖南省自然科学基金（2021JJ40026）；湖南省教育厅科学研究项目（21C0651） |
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| 中文摘要: |
| 产卵场特有的水力条件是四大家鱼繁衍的重要因素，尤其是流量脉冲引发的流速上涨是刺激家鱼产卵、保证鱼卵孵化的关键水力因子；流域梯级开发改变了天然河道的流量脉冲过程，导致产卵场破碎萎缩、鱼苗锐减。为揭示梯级开发对湘江干流四大家鱼产卵场水力特征的影响机理，建立了湘江干流家鱼产卵场二维数值模型，模拟了梯级开发前后典型高低流量脉冲过程，分析梯级开发对鱼类产卵场的影响。结果表明，梯级开发后，水流结构复杂性减弱甚至消失，高、低流速脉冲过程变得“尖锐”，流速上涨时间缩短50%（高流量脉冲）和67%（低流量脉冲），高流量过程的 “喜好流速”或“触发流速”基本消失，低流量过程大部分流速均低于“腰点流速”；对流速上涨过程中平均流速分级水域面积统计表明，低于“腰点流速”面积分别扩大至3.0倍（Q高）和3.2倍（Q低），“感应流速”范围水域面积减少至天然情况的15.8%（Q高）和1.2%（Q低），“触发流速”范围面积减小至天然情况的1.5%（Q高）和1.6%（Q低），“喜好流速”范围面积减小至天然情况的2.0%（Q高）和3.1%（Q低）。研究结果可为鱼类资源保护和恢复等措施提供参考和依据。 |
| 英文摘要: |
| The specific hydraulic conditions in spawning grounds are important factors for the reproduction of the four major Chinese carps. The increases in flow velocity caused by natural flow pulses is the key hydraulic characteristic that stimulates spawning and promotes egg hatching. Cascaded hydropower development has changed the flow pulse process that occurred in the natural channel, resulting in the loss and shrinkage of spawning grounds and a sharp decrease in fish fry. In this study, the spawning grounds on the stem of the Xiangjiang River were selected for a case study, and we explored the influence of cascaded hydropower development on the spawning grounds of the four major Chinese carps in Xiangjiang River. A two-dimensional numerical model of a spawning ground was developed to simulate the typical pulses resulting from alternating high and low flows, before and after construction of cascaded hydropower stations. The model was then used to analyze changes in the hydraulics of the spawning grounds as well as the adverse effects of cascaded stations on spawning grounds. Results show that flow structure complexity decreased and even disappeared after cascaded hydropower development. The high and low flow pulses occurred more suddenly, with the time of velocity increase declined by 50% for the high flow pulse and by 67% for the low flow pulse. The favored velocity (induction velocity) beneficial for fish spawning largely disappeared during high flow process, and the flow velocity was mostly lower than the velocity beneficial for eggs hatching and fry drifting during periods of low flow. Hydropower development significantly decreased the flow velocity of the affected river sections, and the water area of different velocity levels decreased. The water area below the lower velocity limit for fish spawning and egg hatching during the high flow period (Qh) increased by 3 times that before hydropower development and by 3.2 times during the low flow period (Ql). Compared to natural conditions, the induction velocity area was reduced by 15.8% (Qh) and 1.2% (Ql), the triggered velocity area was reduced to 1.5% (Qh) and 1.6% (Ql), and the preferred velocity area reduced to 2.0% (Qh) and 3.1% (Ql). In general, hydropower development on Xiangjiang River has altered flow velocities in the spawning grounds of the four major Chinese carps and adversely affected spawning. Furthermore, the two-dimensional numerical model developed in this study worked well for analyzing the hydraulic conditions before and after development of cascaded hydropower. This study will provide reference and evidence for the conservation and recovery of fishery resource. |
| 曹艳敏,王崇宇,乾东岳.2022.梯级开发对家鱼产卵场高低流量过程的影响[J].水生态学杂志,43(3):18-26. |
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