【作者】 樊荣；

【导师】 权全； 武志刚；

【作者基本信息】 西安理工大学 ， 水利工程（专业学位）， 2024， 硕士

【摘要】 生态文明建设是关系中华民族永续发展的根本大计。水电工程生态环效应与调控是国际水利科学研究的长期热点。黄河上游冷水鱼行为特性对水环境变化的响应机制是河流生态修复与生态调度实施的理论基础。本研究基于黄河上游军功-龙羊峡的地形、水文和气象数据,搭建了适宜黄河上游的SWAT模型,模拟了军功-龙羊峡段水文过程时空演变特征。班多-龙羊峡段地形数据、水文数据和气象资料,构建基于MIKE3的水动力和水温模型,以2018年6月-2019年6月为模拟时段,模拟了羊曲水电站建库后班多-龙羊峡段水深、流速和水温变化特征。在此基础上结合改进熵权法建立了鱼类产卵期风险评价指标体系,搭建班多-龙羊峡段花斑裸鲤产卵期生境风险评价模型。主要结论如下:(1)唐乃亥站1960-2019年年平均径流量呈现上升-下降-上升的趋势;年平均径流量序列发生突变的年份为1986年和2017年:其周期性存在3个峰值,分别对应31a、36a、47a,其中47a尺度的峰值最大,说明47a周期震荡最强。(2)构建适用于黄河上游军功-龙羊峡的SWAT模型,划分2000-2016年为率定期,2017-2019年为验证期,率定期决定系数为0.82,纳什效率系数为0.75,验证期决定系数为0.80,纳什效率系数为0.73。模型精度符合要求,模拟结果可信。模拟结果表明,时间尺度上,该河段7月份前后径流量达到峰值,6-10月河段径流量整体较大,其余时段河段径流较小;空间尺度来看,干流径流量大于支流,且在羊曲-龙羊峡段径流量整体较大。(3)构建适用于黄河上游班多-龙羊峡的水动力模型,模拟了班多-龙羊峡段2019年逐月的水深、流速,模拟结果表明,羊曲-龙羊峡段河道的水位变化和流速变化可以看到,该河段适合喜静水的水生生物,但龙羊峡库尾至羊曲坝址间河道曲折狭窄且流速湍急多变,蓄水期局部流速过高,受羊曲水电站调度影响,班多-羊曲段流速相比建库前天然河道明显变缓。(4)羊曲建库后对龙羊峡下泄水温有一定影响,主要表现在春夏两季(2月～8月)羊曲建库后龙羊峡下泄水温略微升高,幅度在0.5℃,秋冬两季(9月至次年1月)下泄水温温度下降,最大不超过1.5℃。(5)本研究确定繁殖期为4-7月,孵化期风险评价时段为5-8月,龙羊峡库尾段临岸区域和河道渐宽的入口区域鱼卵孵化风险较小,时间尺度来看,5月份的时候,近羊曲坝下处产生一处低风险的鱼卵孵化区域;班多-羊曲段几乎没有高风险区域,与繁殖期相似,班多入流处狭窄河段孵化风险较高,此外,河道中心线附近流速较大且水温不满足鱼卵孵化,鱼卵存活风险较高,近岸处风险较低,整体较为适宜。更多还原

【Abstract】 Ecological progress is fundamental to the sustainable development of the Chinese nation.The ecological ring effect and regulation of hydropower engineering is a long-term hot spot in international water science research.The response mechanism of the behavior characteristics of cold water fish to the change of water environment in the upper reaches of the Yellow River is the theoretical basis for the implementation of river ecological restoration and ecological management.Based on the topographic,hydrological and meteorological data of the construction-Longyang Gorge in the upper reaches of the Yellow River,a SWAT model suitable for the upper reaches of the Yellow River was constructed to simulate the spatio-temporal evolution characteristics of the hydrologic process in the construction-Longyang Gorge section.Based on the topographic data,hydrological data and meteorological data of the BanduoLongyangxia section,the MIKE3 hydrodynamic and water temperature model was constructed.Taking 2019 as the simulation period,the variation characteristics of water depth,velocity and water temperature in the Banduo-Longyangxia section after the construction of the Yangqu hydropower Station were simulated.On this basis,the risk assessment index system of fish spawning period was established with the improved entropy weight method,and the habitat risk assessment model of Gymnoplectra miliei in Banduo-Longyangxia was established.The main conclusions are as follows:(1)The annual average runoff of Tangnaihai Station from 1960 to 2019 showed an ascending-descending-ascending trend;The abrupt changes of annual mean runoff series occurred in 1986 and 2017.There are three peaks in its periodicity,corresponding to 31a,36a and 47a respectively,of which the peak value of 47a scale is the largest,indicating that the 47a periodic oscillation is the strongest.(2)The SWAT model applicable to the construction of Longyang Gorge in the upper reaches of the Yellow River was constructed and divided into 2000-2016 as the rate period,2017-2019 as the validation period,with the coefficient of determination of the rate period being 0.82,the coefficient of Nash efficiency being 0.75,the coefficient of determination of the validation period being 0.80,and the coefficient of Nash efficiency being 0.73.The accuracy of the model meets the requirements and the simulation results are reliable.The simulation results show that,in terms of time scale,the runoff reaches its peak around July,the overall runoff in the section from June to October is larger,and the runoff in the rest period is smaller.In terms of spatial scale,the runoff of the main stream is larger than that of the tributaries,and the overall runoff of the Yangqu-Longyangxia section is larger.(3)A hydrodynamic model applicable to the Banduo-Longyang Gorge in the upper reaches of the Yellow River was constructed to simulate the monthly water depth and velocity of the Banduo-Longyang Gorge section in 2019.The simulation results show that the changes in water level and velocity of the Yangqu-Longyang Gorge section are suitable for aquatic creatures that like quiet water,but the river from the end of the Longyang Gorge reservoir to the Yangqu Dam site is tortuous and narrow,and the velocity is rapid and changeable.Due to the influence of Yangqu hydropower Station operation,the velocity of the Banduo-Yangqu section was significantly slower than that of the natural river before the reservoir construction.(4)After the construction of Yangqu reservoir,the drainage water temperature of Longyang Gorge was affected to a certain extent,mainly in spring and summer(from February to August)after the construction of Yangqu reservoir,the drainage water temperature of Longyang Gorge increased slightly,with a range of 0.5℃,and in autumn and winter(from September to January of the following year),the drainage water temperature decreased,with a maximum of 1.5℃.(5)This study determined that the breeding period was from April to July,and the risk assessment period of the incubation period was from May to August.The risk of hatching fish eggs in the coastal area at the end of the Longyangxia reservoir and in the entrance area of the widening river channel was relatively small.In terms of time scale,a low-risk hatching area of fish eggs appeared near the bottom of Yangqu Dam in May.There are almost no high-risk areas in the Banduo-Yangqu section,which is similar to the breeding period,and the hatching risk is higher in the narrow river section at the inlet of Banduo-Yangqu.In addition,the high velocity near the center line of the river and the water temperature are not sufficient for the hatching of fish eggs,while the risk near the shore is lower,which is generally more suitable.更多还原