| 摘要: |
| 水库建设促进了库区渔业养殖的发展,但高坝大库泄水导致的总溶解气体(Total Dissolved Gas, TDG)过饱和可能导致下游河道尤其下一梯级水库的鱼类患气泡病甚至死亡。为探究TDG过饱和对鱼类的胁迫效应,以金沙江梯级电站溪洛渡至向家坝江段为研究对象,构建了立面二维TDG动态模型,推求了库区控制断面的安全水深阈值,结合库区主要鱼类生活习性和网箱养殖深度,研究了TDG过饱和对野生鱼类和网箱养殖鱼类的胁迫效应。结果表明：梯级电站库区的野生鱼类具有足够的垂向空间进行深度补偿以规避TDG过饱和的危害,其生活习性以及利用深度补偿的能力决定了受过饱和TDG胁迫的程度；但养殖鱼类受网箱限制难以自由下潜至安全水深,为保证养殖鱼类的安全,网箱深度至少应大于安全水深阈值,在TDG过饱和胁迫期,鱼类的游泳水深应持续限制在安全水深阈值以下。对于具有利用深度补偿能力的鱼类,梯级电站的库区比最后一个梯级的下游河道更安全,需要对最后一级电站实施比中间梯级更严格的坝下近区TDG饱和度限制标准。本研究可为TDG过饱和胁迫下的梯级电站生态调度及下游河道养殖鱼类适应性管理提供科学依据。 |
| 关键词: 总溶解气体 深度补偿 安全水深 网箱深度 梯级电站 |
| DOI： |
| 分类号:TV 135 |
| 基金项目:国家重点基础研究发展计划（973计划）,国家杰出青年科学基金,国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| Effect of total dissolved gas supersaturation on fish in the reservoir between cascade hydropower stations and its countermeasures |
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Zeng Chen Jun1,2, Mo Kang Le1,2, Guan Tie Sheng1,2, Chen Qiu Wen1,2, Li Ting1,2, Zhang Hui1,2
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1.Nanjing Hydraulic Research Institute &2.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering
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| Abstract: |
| The construction of reservoirs can promotes the development of fishery while the flow discharge from the high dam would cause the generation of total dissolved gas (TDG) supersaturation, which is detrimental to the fish in downstream reservoir and may result in gas bubble disease (GBD). With the propose of investigating the effect of TDG supersaturation on fish in the Xiangjiaba Reservoir on the Jinshajiang River, a laterally averaged dynamic model for TDG transport was established, and the threshold of safe depth for the control section was investigated. Then, the impact of TDG supersaturation on wild freshwater fish and cage-culture fish were explored based on the fish habits and net cage depth. The results indicated that the reservoirs can provide enough vertical space for wild freshwater fish to swim and acquire hydrostatic compensation to avoid GBD; the risk of fish suffering from TDG supersaturation depends on the habits of fish and the ability to compensate with hydrostatic pressure. Considering the limit of net cage depth, cage-culture fish does not have enough vertical space to swimming to safety depth. To prevent fish from suffering from GBD, the net cage depth should be deeper than the threshold of safe depth, and the fish should be kept under the threshold of safe depth during the period of TDG supersaturation. Besides, the reservoir between cascade hydropower stations was safer than the reach downstream of the last cascade hydropower station. Therefore, it is necessary to establish the strictest TDG limitation standard for the last cascade hydropower station. This work can provide a scientific foundation for ecological regulation of cascade hydropower stations and managements of cage-culture under the threat of supersaturated TDG. |
| Key words: total dissolved gas hydrostatic compensation safe depth net cage depth cascade hydropower stations |
