基于人造洪峰的三峡梯级生态调度仿真分析

为分析三峡-葛洲坝梯级电站(三峡梯级)生态调度效果及其影响,从保证三峡梯级下游河道生态流量、改善江湖连通和保护生物多样性等方面出发,制定了三峡梯级的生态调度目标,并在常规调度的基础上提出基于人工造峰的生态调度方法,通过多种调度方式的仿真结果,分析了不同来水条件下三峡梯级生态调度的效果,揭示了不同生态调度目标之间的影响以...     

裕溪船闸扩建工程枢纽布置优化试验研究

为保证通航安全,船闸设计规范对船闸上下游引航道内的水流条件提出了很高的要求,而船闸通航常常受到泄洪建筑物运行的影响,通航条件恶化。通过试验优化泄洪建筑物与船闸所组成的枢纽的平面布置,优化泄洪建筑物调度运用方案,可以最大程度地减小泄洪建筑物运行时对船闸通航的影响,并且通过试验拟定合理的船闸调度方案和划定通航警戒区域。     

大伙房水库泄洪风险分析

水库对天然河道来水调蓄,下游防洪安全具有重要的作用。在水库防洪调度中,水库泄洪的不确定性造成下游防洪安全具有一定的风险。计算泄洪风险要综合考虑泄洪过程中的不确定性因素,即水文因素和水力因素。在这些因素中,洪水过程的不确定性对泄洪风险的影响是不能忽略的。     

三江平原地下水开采对生态过程的影响

黑龙江省三江平原地下水参与沼泽湿地生态的形成过程。大规模开采地下水对三江平原生态过程的退化产生了较大的影响。应科学合理开发国境界河(湖)水资源,通过联合调度地表水与地下水来缓减当前地下水资源的超载压力,在巩固和发展三江平原商品粮基地的同时,高度关注并维持、保护和恢复三江平原现有湿地生态水文过程和湿地生物多样性。     

膜进样质谱仪法在测量水体中过饱和溶解氮气的应用研究

高坝泄洪会导致水中溶解气体过饱和,使鱼类患气泡病甚至死亡。为探究大坝泄洪条件下,真实水体中的过饱和溶解氮的生成及其随泄洪条件的时空变化规律,利用膜进样质谱仪开展向家坝水电站泄洪条件下溶解氮的测量。结果表明,野外条件下采样运输过程中溶解气体的释放损失,导致膜进样质谱仪测量得到的溶解氮含量比通过利用总溶解气体和溶解氧的现场实测值计算得到的溶解氮含量低;利用质谱仪测量得到的溶解氮测值与总溶解气体测值之间同增的趋势性较好,但溶解氮测值与溶解氧测值之间相关关系较差。总结下来,向家坝电站泄洪导致坝下溶解氮、溶解氧和总溶解气体均达到过饱和,溶解气体饱和度在横向上基本均匀分布;受上游溪洛渡泄洪影响,向家坝坝前仍保持一定程度的溶解气体过饱和,并在垂向上表现出不均匀分布;泄洪生成的溶解气体饱和度随泄洪流量的增大而增大。为保证测量精度,建议原位开展测量,避免采样后长距离运输造成溶解气体的损失;在测量条件不满足的情况下,建议测量总溶解气体和溶解氧后进行溶解氮值换算。     

人工通江湖泊非汛期生态调度方案研究

除鄱阳湖和洞庭湖外,长江中下游通江湖泊基本以涵闸形式连通江湖。由于缺乏水体的自然交换,此类湖泊经常出现水质超标的情况,特别是枯水期。以华阳河湖群为例,通过实测资料分析、现场调研、数值模拟研究了其进行生态调度的可行性及具体方案。研究结果表明:华阳河湖群TN、TP浓度随水位的升高呈下降趋势,但当湖群水位超过某值(13.5 m)后,浓度下降趋势变缓,且湖群9月下旬多年平均水位高于现行非汛期控制水位,因此,利用华阳和杨湾闸进行湖群非汛期生态调度是可行的。在考虑现行闸门调度方式、江湖关系、确保防洪安全和水环境改善4个原则的基础上,结合数值模拟结果,确定了华阳河湖群非汛期生态调度方案,即利用杨湾闸和华阳闸控制湖区10—12月份水位控制在13 m,1—2月份控制在12.5 m,3—4月份控制在11.8 m。     

观音岩水库防洪调度及减灾措施

针对观音岩水库可调库容小,汛期洪水流量较大,下游水位波动适应能力差,泄洪时安全隐患多等情况,分析了观音岩水库防洪调度存在的主要问题,并提出防洪调度的应对措施。通过采取提高信息采集速度和精度,发挥梯级水库联合调度作用,提前发布泄洪公告,加强宣传,安装无线泄洪广播,建立水情信息工作群,控制流量上升速度等措施,既确保水库水位变幅满足要求,又避免因水库泄洪引发不安全事件,可为承担下游城市防洪任务和泄洪影响区较复杂的水库洪水调度提供参考。     

针对小江回水区水华现象的生态调度方案评估

水库生态调度是一种有效的生态补偿手段,通过合理的水库调度方式,可以弥补或减缓水利工程对生态环境造成的影响。综合考虑开县消落带的生态需求和现行三峡水库的调度运行特点,应用验证后的生态动力学模型,模拟出小江调节坝调度方案。提出适用于小江调度方案优化的评估指标体系,根据不同调度方案下调节坝上下游水位、流速和水质情况,利用层次分析法对调度方案进行评估分析,确定调节坝的最优调度方案。研究证明,通过对调节坝的合理调度来改变下游河流水动力条件,可以抑制藻类大量繁殖生长以及改变河流营养盐分布。为以生态调度控藻为目的制定合理的小江生态调度方案提供了可靠的依据。     

浅析高州水库泄洪对高州城区防洪的影响

高州水库位于高州市城区上游30 km,是一宗总库容11.5×108m3的大型水库,对于鉴江中、下游地区的防洪和水资源调度起着关键性的作用,特别是对高州城区防洪影响最大。通过水库泄洪量影响高州水文站的洪峰水位来分析对高州城区防洪的影响。     

三峡三期工程施工期泄洪调度运行水力学研究

三峡工程2002年11月实行明渠封堵截流后，工程建设转入三期工程施工。2003年6月上句，三峡工程将进入库水位为135m围堰挡水发电期。此期间枢纽泄洪调度运行的有关水力学问题是一个复杂而重要的课题。利用模型试验，研究枢纽泄洪对枢纽建筑物及工程设施运用安全、护岸防护等水力学方面的影响，通过泄洪设施运行调度的对比、优化，推荐较优的枢纽调度方式，为设计编制调度规程参用。     

Tolerance and avoidance mechanisms of the rare and endemic fish of the upper Yangtze River to total dissolved gas supersaturation by hydropower stations

Several superhigh dams (greater than 200 m in height) and many high dams have been built in the upper Yangtze River basin in recent years, and these dams have made total dissolved gas (TDG) supersaturation a serious environmental problem. A few studies have examined the tolerance and avoidance characteristics of rare and endemic fish in TDG‐supersaturated water in the upper Yangtze River over the past 10 years. These studies focused on specific species and specific sizes and did not identify a regular pattern that can be applied to all resident fish in the upper Yangtze River. However, elucidating this type of pattern is crucial for fishery management and dam operations in the upper Yangtze River. Data on the median lethal time (LT₅₀), horizontal avoidance percentage, and vertical water depth of three rare and endemic species in the upper Yangtze River from previous studies were used in the current work. An exponential relationship was found between LT₅₀ of fish and TDG supersaturation. The avoidance percentage of fish has a linear relationship with TDG supersaturation. Fish in the upper Yangtze River can use depth compensation to avoid the threat of TDG when the saturation is 130% or above but rarely avoid the threat of TDG when the saturation is less than 125%. We also described the tolerance and avoidance characteristics of fish in a TDG‐supersaturated river downstream from a super‐high dam. When the dam discharged a two‐year flood, the LT₅₀ values of fish downstream ranged from 9.1 to 27.5 hr regardless of depth compensation. The avoidance percentage of resident fish ranged from 8.4 to 44.8%. The resident fish swam to a water depth of 2.43–3.33 m to avoid the threat of TDG.     

龚嘴水电站总溶解气体过饱和原型观测结果分析

大坝泄水对环境的不利影响之一是会产生总溶解气体(TDG)过饱和现象,导致鱼类患气泡病甚至死亡.在理论分析的基础上,建立了基于面流消能的TDG过饱和浓度预测公式.该预测公式采用平均静水压强作为自变量进行TDG饱和度计算,避免了以往采用很难精确定量的动水压强进行TDG预测而带来的不便.通过对大渡河上龚嘴水电站泄洪期间TDG...     

In situ study on the impact of total dissolved gas supersaturation on endemic fish in the Upper Yangtze River

Total dissolved gas (TDG) supersaturation in the upper Yangtze River caused by high spill rates upstream of hydroelectric dams has become a serious environmental problem in recent years. TDG supersaturation downstream of the Xiangjiaba Dam was investigated during flood periods in 2014 and 2015. Alongside this, an in situ study was conducted to evaluate the impacts of TDG supersaturation on grass carp (Ctenopharyngodon idellus) and rock carp (Procypris rabaudi). TDG supersaturation levels ranged from 115% to 131% in 2014 and from 118% to 128% in 2015. During 2014, TDG supersaturation first decreased and then increased and finally remained relatively stable. In contrast, the TDG supersaturation level remained between 122–126% for a relatively long time in the 2015 study period. During 2014, grass carp confined to water depths of 0–1 and 1–2 m began to die after 45 hr of exposure, and most grass carp died between 90 and 130 hr when TDG supersaturation level was greater than 127%. The first observed death during 2015 occurred after 30‐hr exposure. The survival of rock carp was greater than 50% when they were restricted to water depths of 0–1 m. Only three rock carp died when they were confined to water depths of 0–2 m, and no dead fish were recorded at water depths of 0–3 m.     

高坝下游水中总溶解气体过饱和研究进展

随着水电工程的不断兴起,高坝建设引起的过饱和水体问题日渐突出。总结了近年来国内外的的研究成果,从鱼类的耐受性、鱼类对过饱和总溶解气体(TDG)的规避效应以及过饱和TDG对鱼类的致死机理3方面分析了过饱和TDG与下游水生生物之间的相互作用,并提出了一些研究思路和想法。此外,还重点论述了促进过饱和TDG释放速率方面取得的进展和不足之处,指出实际工况条件下过饱和TDG的释放易受河流形态等周边环境影响,而实验条件下无法准确反映实际工况,今后室内试验和原型观测需进一步加强。而如何在安全行洪的前提下实现快速高效的TDG释放是该领域下一步研究的重点。     

Does swimming activity influence gas bubble trauma in fish?

Total dissolved gas (TDG) supersaturation from sources such as hydroelectric dams can cause harmful bubble growth in the tissues of aquatic animals, known as gas bubble trauma (GBT). Locomotion is known to exacerbate bubble growth in tissues during decompression under certain conditions (such as in diving animals), possibly because of increased bubble nucleation. As with decompression sickness, GBT is caused by the supersaturation of tissues with gas, and thus we hypothesize that locomotion promotes bubble nucleation in the tissues of fish exposed to TDG supersaturation. Many previous laboratory studies have tested the effects of TDG on fish exposed to low-velocity, non-directional flow, whereas fish in field conditions are exposed to higher-velocity flows and are likely more active. Therefore, it is important to understand the effects of locomotion on GBT to apply laboratory results to active fish in field conditions. We exposed rainbow trout (Oncorhynchus mykiss) to either control (100% TDG) or TDG supersaturation (123% TDG) in either static or flowing water conditions (1.8 Bl/s) and recorded time to 50% loss of equilibrium (LOE). We observed no statistically significant difference in time to 50% LOE between flow conditions. Given the lack of statistically significant difference between static and flowing water, our findings indicate that results from GBT experiments on rainbow trout in non-directional flow are applicable to more active individuals.     

A parameter analysis of a two-phase flow model for supersaturated total dissolved gas downstream spillways

A high concentration of the total dissolved gas(TDG) in a flow downstream high dams may cause the gas bubble disease in fishes.To better understand the spatial distribution of a supersaturated TDG,a numerical simulation approach for determining the TDG concentration is shown to be effective and convenient; however,the determination of the model parameters relies to a great extent on the observed field data,which are scarce but are very sensitive to the accuracy of the simulation.In this regard,determining the source parameter in the TDG transport equation is the primary concern of this paper.Observed field data from six different spillways in China are used to calibrate the source parameter.A relationship between the source parameter and the hydrodynamic characteristics is established.The inclusion of this relationship in the predictive relationship will enable an accurate and rapid estimation of the source parameter and may help in developing mitigation measures for the TDG supersaturation downstream the spillways.     

水库泄水总溶解气体过饱和对鱼类的危害

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，构建立面二维TDG动态模型，推求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。     

Experimental study on total dissolved gas supersaturation in water

More and more high dams have been constructed and operated in China. The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth), aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the...     

鱼类在TDG过饱和含沙水体中的耐受性

为探讨高坝泄洪引起的总溶解气体(TDG)过饱和含沙水体对鱼类的影响,以岩原鲤和鲢鱼为研究对象,开展TDG过饱和含沙水体对不同鱼类的急性暴露试验,根据鱼类受TDG过饱和含沙水体胁迫后的异常行为和死亡率、半致死时间等指标来分析不同鱼类受胁迫后的耐受性和差异性。试验结果表明:试验初期,试验用鱼出现较明显异常行为和气泡病症状,且岩原鲤早于鲢鱼;相同TDG饱和度下,随着含沙量的增加,试验用鱼半致死时间缩短,且岩原鲤半致死时间短于鲢鱼,表明鲢鱼比岩原鲤具有更强的适应能力和耐受能力;当TDG饱和度较高时,即使含沙量低,也会造成试验用鱼的大量死亡;过饱和TDG是导致试验用鱼死亡的主要原因,但不能忽略泥沙对试验用鱼死亡的促进作用。     

三峡工程坝身泄流下游水体溶解氧浓度数值模拟

三峡工程坝身泄流与下游水体强烈碰撞,产生大量气泡,当气泡渗透进入水体一定深处时,气泡界面与水体之间的质量交换极易导致水体溶解气体浓度超饱和,可导致鱼类气泡病.该文应用气泡界面传质理论建立了掺气水流的溶解氧浓度对流扩散方程,与气液两相流混合模型相耦合,模拟计算了三峡大坝在库水位为139m情况下溶解氧浓度变化情况,成功地与现场观测数据进行了验证,完善了气泡界面传质系数公式.对关键因子进行敏感分析,表明气含率、紊动强度、下游水深是决定溶解氧浓度的关键因素.