基于鱼类生境所需水文-水力特征的生态流量计算方法

张丽亭; 逄勇; 汪静娴; 季汇玲; 张舒文

doi:10.13928/j.cnki.wrahe.2025.01.009

水利水电技术（中英文） ›› 2025, Vol. 56 ›› Issue (1) : 100 -112. DOI: 10.13928/j.cnki.wrahe.2025.01.009

生态水文机理与流域管理策略专栏

基于鱼类生境所需水文-水力特征的生态流量计算方法

张丽亭 ¹^,² ,
逄勇 ¹^,² ,
汪静娴 ¹^,² ,
季汇玲 ¹^,² ,
张舒文 ¹^,²

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A method for determining the basic ecological flow of riverways through comprehensive hydrology, water conservancy, and habitat simulation analysis

Liting ZHANG ¹^,² ,
Yong PANG ¹^,² ,
Jingxian WANG ¹^,² ,
Huiling JI ¹^,² ,
Shuwen ZHANG ¹^,²

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摘要

【目的】为保障叶尔羌河的生态用水并科学合理确定生态流量，【方法】基于长系列水文资料，采用面积比指数法对研究河段进行径流推求，得出控制断面长系列径流成果；根据径流计算数据和实测断面信息，使用水力学计算方法得出在不同流量条件下的水深、湿周、流速和水面宽等水力特性。同时，结合鱼类栖息地需求的水力参数，运用Tennant法、湿周法、Q90法和生态水力学法等四种不同方法综合确定该断面的生态流量。根据生态流量计算结果，分析天然来流和生态流量下泄两种情形下的下游断面水文水力特征变化情况。【结果】通过对多种计算方法进行比较分析，确定在叶尔羌河流域米斯克尼坝址断面，枯水期(10月至次年3月)的最小下泄生态流量为多年平均流量的10%,即14.3 m³/s;而在鱼类繁殖期和丰水期(4月至9月),下泄的生态流量应为多年平均流量的30%,即42.9 m³/s。采取以上计算结果进行生态流量下泄，下游河道断面水力参数均有不同程度的改变，与平水年天然来流相比流量降低79.6%、流速降低48.3%、水深减小31.4%、水面宽减小26.1%。【结论】以上基于鱼类生境需求，结合水文学、水力学方法的河道生态流量计算方法较为合理，且能根据鱼类产卵时间划分出精确的生态流量。河道内仅下泄生态流量会导致断面水深、水面宽、流速等水力参数发生较大的改变，在保证鱼类生态流量的同时还需考虑流量减少对其他动物或植被的影响。

Abstract

[Objective] To ensure the ecological water use of the Yarkand River and scientifically determine the ecological flow rate, [Methods] the area ratio index method based on long-term hydrological data was utilized to calculate the runoff of the studied river section. This approach yielded the long-term runoff result for the control section. Using these runoff calculations and measured cross-sectional information, hydraulic calculation method was applied to obtain hydraulic characteristics such as water depth, wetted perimeter, flow velocity, and water surface width under different flow conditions.To comprehensively determine the ecological flow rate of the section, there are four different method employeel: the Tennant method, the wetted perimeter method, the Q90 method, and the ecological hydraulic method. These method were based on the hydraulic parameters required for fish habitat. Subsequently, the changes in hydrological and hydraulic characteristics of downstream sections under two scenarios: natural inflow and ecological flow discharge.[Results] By comparing and analyzing multiple calculation method, the minimum ecological discharge during the dry season(October to March of the following year) at the Miskni dam site section in the Yarkand River Basin is 10% of the average annual flow, which is 14.3 m³/s. During the breeding season of fish and the wet season(April to September), the ecological flow discharge should be 30% of the average annual flow, which is 42.9 m³/s. Using these ecological flow discharge calculations, changes in the hydraulic parameters of the downstream river section. Compared to the natural inflow in normal years, the flow rate decreased by 79.6%, the flow velocity decreased by 48.3%, the water depth decreased by 31.4%, and the water surface width decreased by 26.1%.[Conclusion] The calculation method for river ecological flow, based on the habitat requirements of fish and combined with hydrological and hydraulic method, is relatively reasonable. It can accurately determine the ecological flow according to the spawning time of fish.However, releasing only the ecological flow in the river can cause significant changes in hydraulic parameters such as cross-sectional water depth, water surface width, and flow velocity. While ensuring the ecological flow for fish, the impact of reduced flow on other animals or vegetation should also be considered.