Effect of stream regulation on population parameters of atlantic salmon [Salmo salar L.] in the river Lærdalselva,western Norway

The river Lærdalselva, West Norway, was regulated in the autumn of 1974. Regulation led to an increase in winter flow and a decrease in summer flow in a section where there was natural production of salmon. A slight decrease in summer temperature was also recorded in the uppermost part of this section. No data existed on juvenile Atlantic salmon before regulation and the regulation effect on juvenile fish population parameters is therefore based on samples taken from adult salmon in the period 1969 to 1984. No differences in growth, smolt age, and smolt size which could be related to the regulation of the river were found. The smallest mean sizes of yearlings (0+) were found in 1964 and 1967. After regulation the mean size was never lower than before. Mean smolt age was between 3–1 and 3–9 years, but after regulation never exceeded that found before. River growth was slow, three year old smolts growing faster than four year old smolts. However, there were no differences in river growth before and after regulation.     

Atlantic salmon (Salmo salar) in the regulated River Alta: effects of altered water temperature on parr growth

The chief objective of this study was to analyse the effects of altered water temperature, due to the hydropower regulation of the River Alta, on growth of Atlantic salmon parr. The river was developed for hydroelectric purposes in 1987. A 110 m high concrete dam was built in the main river 49 km upstream from the outlet to the sea. The outlet of the power station is located 2.5 km downstream from the dam. The annual regime of water temperature has been altered downstream from the power station because of the regulation. It has decreased 1–2° C during June, July and the first half of August, while it has increased up to 3° C during late summer. During winter, water temperature has increased from 0° C to about 0.3–0.4° C. Atlantic salmon is the predominant fish species in the river. They can penetrate 46 km from the sea, up to the outlet of the power station. In this paper I have studied the relationship between growth of juvenile Atlantic salmon and water temperature in the upper part of the river. At similar temperatures, the growth rate of salmon parr in the River Alta is higher in early summer than later in the growing season. In early summer the salmon grew faster than the maximum rate predicted by a recently published model. Therefore, I adjusted the model to describe growth rates of salmon in early summer (ice break to mid‐August), using data derived prior to the hydropower development (1981–1986). The new model proved effective at describing growth rates of fish in early summer following the hydropower development (1987–1996). After development, growth rates decreased during early summer, but increased correspondingly later in the season. There was close agreement between these growth changes and the altered annual regime of river temperature. Overall, only minor changes in annual growth rates have been observed after the hydropower development. Copyright © 2003 John Wiley & Sons, Ltd.     

Growth and Smoltification of Three Norwegian Strains of Atlantic Salmon Salmo salar Reared under Different Thermal Regimes

A comparative study was performed with juvenile Atlantic salmon Salmo salar from three stocks in Western Norway that differ in their natural conditions. One is from warm, lowland river conditions (Årdal), one is from cold glacial river conditions (Stryn) and the last one (Suldalslågen) is from a hydropower‐regulated river. The salmon parr were tagged and reared at 4, 5.5 and 7 °C and simulated natural water temperature (SNT) for river Suldalslågen. Size distribution was unimodal at 4 °C, with a change to a bimodal distribution, representing potential 1+ and 2+ smolts, at the other temperature regimes. The relative biomass of 1+ smolts varied between the stocks as Stryn (cold glacial river) stock had the highest number of smolts at 7 °C and the Suldalsågen stock (hydropower‐regulated river) displaying the highest number at the SNT regime. Overall, the Stryn stock, originating from cold river conditions, seemed to be well adapted to growth and smoltification at cold temperatures, whereas salmon parr from river Suldalslågen seem to be better adapted to the natural temperature regime (SNT) of this river than the other two stocks. This was reflected in the gill Na⁺,K⁺‐ATPase as the Suldalslågen stock showed increasing activity from 16 April (4.2 µmol ADP mg protein^?1 h^?1) to 10 May (9.2 µmol ADP mg protein^?1 h^?1), and at the end of the experiment, enzyme activity in Suldalslågen stock was significantly higher than both Stryn (5.7) and Årdal (5.9 µmol ADP mg protein^?1 h^?1) stock. In contrast, the warm lowland stock, Årdal, fish had low Na⁺,K⁺‐ATPase activity with no distinct peak at any of the sampled dates from March through May. Copyright © 2016 John Wiley & Sons, Ltd.     

基于河势稳定原理的黄河游荡性河道整治机制研究

依据黄河下游游荡性河段河势查勘资料分析,结合河工实体动床模型试验,探讨了游荡性河道河势稳定原理,研究了基于河势相对稳定原理的河道整治机制。研究表明,尽管游荡性河道河势调整多变,但其调整是遵循河势稳定原理的;游荡性河道整治应按照"顺势布弯、就弯设坝、遥相呼应、规模适度"的原则和方法确定整治工程体系布局。以此研究成果建设的工程体系运行实践表明,在近年来不同流量级洪水下整治工程体系可以明显起到理顺流路、稳定河势的作用。     

三峡工程运用初期荆江河段调关弯道冲淤演变试验研究

三峡水库修建后,由于水库调蓄作用,进入坝下游荆江河道的水沙过程发生了显著变化。荆江河道产生较明显的冲刷,已引起局部河段的河势调整,将在相当长时期内对两岸堤防、已建护岸工程和河道整治工程及河道的稳定产生不同程度影响,进而影响该地区的防洪、航运、生态与环境,以及河流的综合服务功能的正常发挥。采用长江防洪实体动床模型试验,研究了三峡工程运用初期不同时期荆江重点险工段调关弯道的冲淤变化过程,并在此基础上预测河势调整趋势。研究成果可为该段河道的治理和河势控制工程规划、设计等提供技术参考。     

长江河口段节点控导作用及河势格局研究

长江河口段所在的长江三角洲地区,经济发展对河道整治提出了较高要求。对长江河口段的节点进行了梳理,从节点稳定性、节点对河道控导长度、节点间河道最大摆动幅度等方面,分析了节点对河势的控导作用,认识到节点河段是控制上下游分汊河段河床变化及相互影响的基础条件。河势总体控导的基础在于加强节点河段的稳定性和控制作用,应采取相应的工程措施稳定洲滩,进而稳定深槽,对局部岸线和洲滩崩退的重点部位进行守护。     

黄河前3次调水调沙试验对河口区段的影响

通过对前3次调水调沙试验期间河口区段河道河势、水情的变化进行分析，表明调水调沙使河势发展趋向理想化，河道过洪能力得到了提高。同时建议：①调水调沙的时间应不少于20d；②对调水调沙试验的效果分析要有一个统一的标准，数据要一致，以便于掌握和对外宣传调水调沙的作用；③2005年调水调沙转入正常运行，对于运行期间的有关指标也要进行统一观测；④对西河口控导工程未建坝岸进行完善；⑤加强对小浪底水库运用后下游河道变化的研究。     

Preference by juvenile Chinese sucker Myxocyprinus asiaticus,for substrate colour in zero versus slow velocity regimes suggest a change in habitat preference of wild juveniles after damming the Yangtze river

Habitat preference of benthic riverine juvenile Chinese sucker, Myxocyprinus asiaticus, a protected species in China, is poorly understood. This situation makes it difficult to evaluate the potential impacts on juveniles after river alteration. To better understand the impact of damming, we studied preference of cultured juvenile Chinese sucker (7.90–8.55 cm, standard length) for dark versus light substrate colours in 2 velocity regimes: zero velocity (like on a reservoir bottom) and in a slow water current of 0.15–0.19 cm/s (like on the bottom of a slow flowing stream). In the slow current regime, juveniles chose black substrate during the day and night. This likely represents the natural substrate preference by wild suckers in a river. However, in the zero velocity regime, juveniles chose a black substrate during the day, but switched preference to a white substrate at night. The results suggest wild juveniles in the natural Yangtze River have evolved a preference for a black substrate during the day and night. However, after the river was impounded by the Three Gorges Dam and bottom velocity changed to a static regime, juveniles in the reservoir changed substrate colour preference and now prefer a light‐coloured substrate colour at night. Thus, damming likely caused a major behavioural change by juveniles. The adaptive significance and effect on fitness of this change in habitat preference is not known but should be investigated as wild Chinese sucker continue to decline in abundance.     

2016洪水+长江中下游防洪与治河问题再探

基于2016—2019年长江防汛与河道查勘新实践、长江中下游洪水与河势的新变化与新形势,以及以往研究基础与成果,总结提出了2016洪水⁺长江中下游防洪与治河10大新问题,即流域水沙变化、河流情势变化、水文节律改变、河道洲滩演变、干流槽蓄变化、江湖关系影响、水位流量关系、防洪布局调整、河湖治理技术,以及河流管护研究。采用“原因Ⅰ-响应Ⅱ-影响Ⅲ-对策Ⅳ”4级体系,对10大新问题进行了体系分类、关系构建、课题分解与研究探讨,构建了“之字形层次驱动”和“田字形关联影响”2组关系。研究增进了三峡工程对长江中下游洪水与河势影响的辨识,强化了对变化条件下长江中下游防洪与治河问题的“层次化”与“系统化”梳理。     

长江下游马鞍山河段河道治理初步研究

 归纳总结了长江马鞍山河段基本情况、近期河道演变特点和河道治理概况;根据现有河势条件及近年崩岸险情,分析指出了目前本河段存在的主要问题;结合河道治理规划情况,探讨了下一步河道治理措施。研究认为：河势调整工程是该河段整治的关键,重点是通过数学模型和河工模型试验研究提出河势调整工程方案;主要是在左岸新河口一带布置导流工程和上下何家洲及心滩串沟封堵并岸工程,并辅以江心洲尾的何家洲尾挖槽工程。鉴于整治工程的紧迫性和时效性,建议相关部门尽快开展相关前期工作,为整治工程早日实施创造条件,进而实现该河段河势的稳定。     

Conceptual Modelling to Assess Hydrological Impacts and Evaluate Environmental Flow Scenarios in Montane River Systems Regulated for Hydropower

To improve understanding of natural and managed flow regimes in data‐sparse regulated river systems in montane areas, the commonly used Hydrologiska Byråns Vattenbalansavdelning (HBV) conceptual run‐off model was adapted to incorporate water regulation components. The extended model was then applied to the heavily regulated river Lyon (391 km²) in Scotland to reconstruct the natural flow regime and to assess the impacts of regulation at increasing spatial scales. Multi‐criteria model evaluation demonstrated that the model performed well in capturing the dominant catchment processes and regulation effects, especially at the timescales at which operation rules apply. The main change as a result of regulation in the river Lyon is a decrease in inter‐annual and intra‐annual variability of all elements of the flow regime, in terms of magnitude, frequency, and duration. Although these impacts are most pronounced directly downstream of the impoundments, the regulation effects propagate throughout the river system. The modelling approach is flexible and widely applicable and only limited amounts of data are required. Moreover, results are easily communicated to stakeholders. It has the potential to contribute to the development of flow regimes that may be more beneficial to the ecological status of rivers. In the case of the river Lyon, it is likely that this involves a more variable release regime. The approach developed here provides a tool for assessing impacts on flow regimes and informing environmental flows in other data‐sparse regions with heavily regulated montane river systems. Copyright © 2014 John Wiley & Sons, Ltd.     

Age‐0 Channel Catfish Ictalurus Punctatus Growth Related to Environmental Conditions in the Channelized Missouri River,Nebraska

Large river paradigms suggest that natural flow regimes are critical for maintaining instream habitats and promoting production and growth of native aquatic organisms. Modifications to the Missouri River, Nebraska, within the past 100 years have drastically reduced shallow water habitat, homogenized the flow regime, and contributed to declines in several native species. Despite drastic flow modifications, several metrics of the Missouri River's flow regime still vary across years. We related age‐0 channel catfish growth to environmental conditions in the channelized Missouri River, Nebraska, between 1996 and 2013 using an information theoretic approach. Growth rate was most influenced by growing season duration and duration of discharges below the 25th percentile of 30‐year daily Missouri River discharges. Periods of low water may be important for juvenile growth because of channel modifications that limit critical shallow water habitat during higher within‐bank flows. Exclusion of peak discharge and peak discharge timing in the best model to predict growth is counter to conventional thoughts on river fish responses to hydrological conditions but may be reflective of the general lack of high‐magnitude flooding during the majority of our study. Future efforts to relate juvenile fish growth to environmental conditions can provide guidance for water management in the Missouri River and other regulated North American rivers. Copyright © 2015 John Wiley & Sons, Ltd.     

三峡工程蓄水后荆江河势变化及整治方案研究

三峡工程蓄水运用以来,荆江局部河段河势发生了新的变化,影响了长江航运。在以往工作基础上,根据实测资料分析了荆江河段的历史演变、近期演变及三峡工程蓄水运用以来的河道冲刷和崩岸等概况。根据数学模型计算结果,预估了荆江河段的河道变化趋势,提出了荆江河段河势控制的初步方案,对沙市河弯、公安河段、石首河弯及监利河弯提出了阶段性的初步治理设想,可为荆江河势演变研究和工程治理提供参考。     

对长江中下游干流河道治理的几点认识

长江中下游干流河道治理与长江流域经济发展关系密切,对长江流域可持续发展发挥着重要的作用.长江中下游干流河道治理要以防洪作为主要目标,充分发挥河道的泄洪能力,保障堤防安全;稳定河势河床是河道治理的基本要求;把保护优良生态环境作为重要内容,树立河道治理与环境治理的协调统一的思想;贯彻综合治理开发的原则,统筹考虑各方利益和要求;按可持续发展的要求不断完善河道治理规划.     

粤港澳大湾区水安全协同调控理论框架研究

针对粤港澳大湾区水问题多维交织特性,基于流域系统整体观梳理总结了技术上可控、逻辑上关联的5个水安全调控子系统结构,包括：河势调控子系统、内河水环境水生态调控子系统、外江咸潮调控子系统、城市暴雨洪涝调控子系统、外江洪潮调控子系统。探讨了各子系统关键机理、系统间的协同作用原理、协同调控的关键技术需求及协同调控模型算法架构,构建了大湾区水安全协同调控理论框架,以珠江河口为例开展了粤港澳大湾区水安全协同调控理论的应用,为大湾区水问题系统治理提出了新的解决方案。     

湘江橘子洲综合治理对防洪及环境影响研究

 采用河势分析和实体模型试验相结合的方法,研究论证了橘子洲综合治理工程对河段河势、防洪及重要涉水建筑物等方面可能产生的影响,并就治理工程对环境的影响进行了分析。研究结果表明,工程兴建有利于洲、水、城市相互融合,易形成良好的区域生态环境,但对附近河段防洪水位、汊道分流比、湘江一桥桥墩局部冲刷会带来一定不利影响。为维护湘江的健康,针对不利影响产生的原因,对治理方案提出了优化改进措施,为工程决策和设计提供了参考依据。     

航道整治水文情势变化对四大家鱼产卵场的影响——以荆江周天河段为例

以长江中游荆江周天河段航道整治工程为例,采用平面二维水动力数学模型,对工程修建后水流流态、水位和流速等水力因素变化进行计算分析,进而研究航道整治工程所导致的水文情势变化对河段内四大家鱼产卵场的影响。研究表明:工程实施后,产卵期水位变化约-0.01～0.01 m,流速变化约为-0.10～0.15 m/s,不会对产卵场水流流态造成大的影响;潜丁坝工程会导致局部流速以及附近河床冲淤的变化,但客观上起到了人工鱼礁的作用,为鱼类提供良好的庇护、栖息及觅食等环境,一定程度上有利于鱼卵的受精和正常孵化;工程水下沉排和抛石使得局部河床地形更为复杂,但对河床地形地貌影响范围和程度较小。     

长江南京新济洲河段河道整治方案研究

在分析长江南京新济洲河段近期河道演变规律的基础上,提出河段在防洪、岸线利用、河势稳定等方面存在的主要问题。针对两岸经济发展的要求,提出两套整治方案,运用数学模型和物理模型相结合的手段,对整治方案进行了比选、优化,并提出了可行的推荐方案,使其有利于该河段及下游河段河势稳定及防洪安全。     

黄河水量统一调度与调水调沙对河口的生态水文影响

从具有生态学意义的流量、频率、出现时间、持续时间和变化率等5种水文要素出发，采用水文变化指标体系定量评估了黄河水量统一调度与调水调沙对河口段生态水文情势的影响，讨论了河口环境水流需求以及调水调沙后水文情势对环境水流的满足程度。研究结果表明，与水量统一调度前相比，水量统一调度与调水调沙后利津断面水文情势有所改善，年极小值流量明显增加，但是水文过程变化率降低，洪水漫滩过程消失，水文过程趋于平缓。目前河口段水文情势能够满足枯水期适宜生态流量需求，汛前4—5月关键期无法满足适宜生态流量与流量脉冲过程，汛期除缺乏洪水脉冲过程外，基本能够满足高流量输沙需求。     

长江石首河段航道整治工程行洪影响研究

分析了长江石首河段航道整治一期工程河段近期河床演变特点及演变趋势,采用平面二维水流数学模型计算分析了工程对河道水位及流场等的影响,并综合分析了工程对河势和行洪的影响。研究结果表明：拟建工程实施后不会对该河段行洪及河势产生明显的不利影响,但局部河势仍会有一定的调整。该研究成果可为航道整治工程设计提供科学依据。