新型低水头挡水闸坝选取原则及注意事项简述

随着汾河流域生态修复工作的全面推进,在河道中新建低水头挡水闸坝已成为生态修复中蓄滞雨水资源,加大河流水域面积、增强地下水补给量、改善河段局部生态环境的重要工程措施之一。本文对目前国内较为常见的几种低水头挡水闸坝主要特点进行了阐述,提出了低水头挡水闸坝坝型选取的原则及注意事项,以期为今后河流生态修复治理工程中类似坝型的选择提供参考。     

河流健康诊断与生态修复

河流生态修复的总体目标是恢复河流健康，实现人与河流的和谐共存。从河流系统诸功能与河流健康之间的关系出发。分析了河流系统平衡的特征和影响因素，初步建立了河流健康诊断指标体系。根据河流受损功能、受损程度及其可修复性。提出了不同阶段河流治理和生态修复的对策。目前采用的主要技术包括：缓冲区修复、植被恢复、河道补水、生物-生态修复、生境修复、水生生物群落修复技术等。河流生态修复是一个多目标、多变量、多层次、多约束条件的动态优化问题，需要因地制宜、全面考虑、科学决策。     

论河流生态修复

本文以河流系统诸功能与河流健康之间的关系为主线，从人与河流关系的发展与变化出发，探讨了原始自然阶段、工程控制阶段、污染治理阶段和河流生态系统修复和改善等四个阶段的河流特点和治理条件，分析了各个阶段河流系统平衡的特征和影响因素，初步建立了河流健康诊断指标体系，提出了河流生态修复的主要原则。河流生态修复的总体目标是恢复河流系统健康，实现人与河流的和谐共存。河流生态修复主要技术包括：缓冲区修复、植被恢复、河道补水、生物-生态修复、生境修复、水生生物群落修复技术等。本文采用层次分析法的基本思想，探讨了河流健康、河流功能、功能要素和生态修复措施四个层次的关系，同时指出了实现河流生态修复的步骤。     

水库报废生态环境影响及其修复

为研究水库报废对生态环境的影响,将水库报废拆坝影响划分为三个层次:以水沙过程为初始影响,视社会和经济影响为最终效应,两者之间为次生影响,并揭示了拆坝影响的综合性、矛盾性、时空延续性及不确定性等特点。从物理、化学、生态三方面明晰了拆坝生态环境影响:物理影响体现对水文、泥沙和地形地貌的影响,拆坝可完全逆转建坝带来的水文影响,淤积的泥沙将重新运移,通过溯源侵蚀使大坝上下游河段逐渐达到相对稳定的坡降;化学影响主要表现为对河流水质的影响;生态影响即可能使水生生物的生境质量得以改善,也可能由于水质退化、物种入侵对水生生境产生负面影响。针对性地提出了拆坝生态修复对策和措施:应通过重新引入乡土植物群落、控制外来物种及顺应植被演替规律修复库区及下游河道濒水植被;清除或降低污染物对生态环境的不利影响;重建河流近岸水文、地貌环境,保护和恢复水生生物;通过生态环境监测,应适时对修复措施进行调整。研究所得成果为报废水库的生态修复提供参考。     

河流廊道与生态修复

河流生态系统受到人类活动的干扰和损害已成为目前社会关注的焦点，受损河流的生态修复研究和实践日益受到人们广泛的重视．在此从生态学的角度，分析了河流廊道的空间结构和生态功能，介绍了河流生态修复的概念与相应的生态修复措施．对发达国家的河流生态修复的研究进展进行了综述，同时介绍了我国河流修复的一些情况．在此基础上，针对我国河流生态修复的现状，指出为做好河流生态修复工作，需要进一步加强河流修复方法、应用技术、示范工程等方面的研究．     

基于河道治理的河流生态修复

阐述河流整治带来的负面影响 ,论证对受损的河流进行生态修复的必要性 .基于河道治理的河流生态修复是指河道形态和河床断面的修复及恢复丧失的河岸带植被和湿地群落 ,可采用的具体方法有 :恢复河道的连续性 ;重现水体流动多样性 ;给河流更多的空间 ;慎重选择河道整治方案 .在介绍国内外相关研究进展情况的基础上对河流生态修复的研究和应用提出合理建议 .     

河流生态修复评价方法探讨

目前,有关河流生态修复评价指标体系研究中缺乏对经济可行性因素的考虑。在分析河流生态修复评价和相关经济可行性研究成果的基础上,通过识别河流生态环境的自然因素和社会因素,探讨了河流周边社会经济因素对河流生态系统修复产生的影响,并从修复必要性评价和经济可行性评价两方面着手构建了适用于河流生态修复评价的指标体系。采用层次分析法对河流生态修复评价指标赋予权重,建立了模糊综合评价模型,为河流生态修复评价研究提供了一种新的方法。最后,以河南省贾鲁河郑州段和周口段为例开展实际应用研究,结果证明本评价方法可行。     

串联型水体生态需水补水方案研究

在水资源长期短缺的北方地区,拦河蓄水形成的串联型河流坝式景观水体几乎在每个城市都可以看到。为计算维持这种以水景观为主的人工河流生态系统基本健康的最小需水量,以滹沱河水环境修复段为例,构造描述"串联型坝式景观水体"水质、水量变化的综合数学模型,提出了水质、水量相结合的河流坝式景观水体生态需水补水方案。结果显示:75%频率降水情况下,滹沱河水环境修复段现状水平年最小需水量为3 450万m3,并给出了明确的补水时机和补水量,为北方串联型河流坝式景观水体的生态保护提供了支撑。     

海河流域平原河流生态修复模式研究Ⅰ——修复模式

由于水量不足、水质恶化及河流天然形态遭到破坏,海河流域大多数平原河流生态健康受到相当程度破坏.因而,对它们进行生态修复,需要建立相应生态修复模式体系对其进行指导.文中总结了现有河流生态修复技术,从中筛选出13种适宜于海河流域的修复技术.依据功能不同,将其分为水量调整技术、水质净化技术和生境改善技术3类.在此基础上,从影响海河流域平原河流生态健康的关键因素--水量入手,综合考虑河流水质与生境现状,提出海河流域平原河流生态修复模式体系.该体系包括4种修复类型(即管理保护、直接修复、补水修复和生态系统替代)和9种修复模式.     

拆坝对河流生态系统的影响及评估方法综述

为研究拆坝对河流生态系统造成的影响,从短期和长期两个时间尺度综合分析了河流水文情势、地形地貌、岸边带植物、鱼类和底栖动物等关键生态因子对拆坝的响应,并总结了目前拆坝对生态系统影响的两种主要评估方法。认为根据实际拆坝情况进行评估和基于数值模型进行预测两种评估方法中,实地观测是最直接、最有说服力的研究方法,但受成本和一些不可控因素限制;数值模拟具有速度快、费用低、无比尺影响等优点,可对拆坝影响进行预测,为管理者提供参考,但精度和准确性有待提高。指出后续研究中应综合考虑拆坝过程中各生态因子间的耦合效应,需对不同拆坝时机和分阶段拆坝方式对河流生态系统的影响进行深入研究。     

梯级拦水堰与曲线槽岸组合的河道水流特性与过鱼效果研究

为提升少水型河道平时的生态和景观效果,提出了一种侧边开口梯级拦水堰与曲线河槽槽岸组合的河道治理形式,并以梯级拦水堰组合直线槽岸作为对照,分别对应梯级拦水堰淹没和非淹没2种不同水深,进行三维水流数值模拟与水力模型试验,分析了相应的水流特性。又以两种不同体长的草鱼幼鱼进行了通行成功率、通行轨迹和通行时长的过鱼试验。结果表明：在同种试验条件下,组合曲线河槽的试验用鱼通行适宜区占比最大为70%左右,分布范围更大,进一步减小了试验用鱼误入非适宜区的可能,过鱼试验结果也优于组合直线河槽,其中试验用鱼通行成功率最高为86%,较组合直线河槽提高10%,通行时间最短为85.4 s,较组合直线河槽时间最大可缩短31.2%,本文的研究结果可为北方山区季节性中小河流等少水河道的整治和河流生态改造提供一定参考和借鉴。     

Fish and fisheries of regulated rivers in the UK

This paper examines the historical and recent influences of river regulation on fish populations and fisheries in Britain. The construction of a series of canals and interconnecting waters during the 18th and 19th centuries facilitated the spread of some species between catchments. These slow-flowing habitats allowed many lowland species to thrive and this is reflected today in the fish community structure in some rivers. The problems of barriers to the movement of migratory species imposed by dams and weirs and the efficacy of compensation measures are discussed. The latter embrace fish passes, adult fish and smolt transport, and stocking. Potential problems for the future include the disruption of the homing of salmon to their natal rivers caused by transfers of water between catchments. River basin management in Britain attempts to reconcile the water resource requirements of fisheries with those of other water users. This can be seen in the practice of Regional Water Authorities to include ameliorative measures in many of their land drainage and flood prevention designs. However, more research is required on the long-term problems and benefits of these and other river regulation schemes on resident fish populations.     

Modelling upstream fish passage in standard box culverts: Interplay between turbulence,fish kinematics,and energetics

Box culverts are common hydraulic structures along rivers and streams, in rural and urban water systems. The expertise in fish‐friendly culvert design is limited, sometimes leading to adverse impact on the catchment ecosystem or to uneconomical structures. Basic dimensional considerations highlight a number of key parameters relevant to any laboratory modelling of upstream fish passage, including the ratio of fish speed fluctuations to fluid velocity fluctuations, the ratios of fish dimensions to turbulent length scale, and the fish species. Alternately, the equation of conservation of momentum may be applied to an individual fish, yielding some deterministic estimate of instantaneous thrust and power expended during fish swimming, including the associated energy consumption. The rate of work required by the fish to deliver thrust is proportional to the cube of the local fluid velocity, and the model results demonstrate the key role of slow‐velocity regions in which fish will minimize their energy consumption when swimming upstream.     

Effects of dams in river networks on fish assemblages in non‐impoundment sections of rivers in Michigan and Wisconsin,USA

Regional assessment of cumulative impacts of dams on riverine fish assemblages provides resource managers essential information for dam operation, potential dam removal, river health assessment and overall ecosystem management. Such an assessment is challenging because characteristics of fish assemblages are not only affected by dams, but also influenced by natural variation and human‐induced modification (in addition to dams) in thermal and flow regimes, physicochemical habitats and biological assemblages. This study evaluated the impacts of dams on river fish assemblages in the non‐impoundment sections of rivers in the states of Michigan and Wisconsin using multiple fish assemblage indicators and multiple approaches to distinguish the influences of dams from those of other natural and human‐induced factors. We found that environmental factors that influence fish assemblages in addition to dams should be incorporated when evaluating regional effects of dams on fish assemblages. Without considering such co‐influential factors, the evaluation is inadequate and potentially misleading. The role of dams alone in determining fish assemblages at a regional spatial scale is relatively small (explained less than 20% of variance) compared with the other environmental factors, such as river size, flow and thermal regimes and land uses jointly. However, our results do demonstrate that downstream and upstream dams can substantially modify fish assemblages in the non‐impoundment sections of rivers. After excluding river size and land‐use influences, our results clearly demonstrate that dams have significant impacts on fish biotic‐integrity and habitat‐and‐social‐preference indicators. The influences of the upstream dams, downstream dams, distance to dams, and dam density differ among the fish indicators, which have different implications for maintaining river biotic integrity, protecting biodiversity and managing fisheries. Copyright © 2010 John Wiley & Sons, Ltd.     

大坝运行过程中泄水对坝下游生态系统的影响分析及控制

大坝运行过程中泄水会对坝下游生态系统产生负面影响,体现在河道生态环境、洪泛区生态环境和河口生态环境中水文水力情势、河道形态和地貌、水质、原有生物生存和繁衍环境等发生变化,生物种类和数量减少,生物多样性降低。因此有必要对河道区、洪泛区和河口区进行水文水质监测、地下水水位监测、鱼类及水生生物监测、动植物种类和生境调查等;同时,确保大坝下游河段环境流量、制定合理的泄水调度方案和实施坝下游生态系统恢复,以期控制负面影响,使坝下游生态系统逐渐呈良性循环。     

吉沙水电站首部枢纽拦河坝设计

吉沙水电站枢纽工程由首部枢纽、左岸有压引水隧洞、调压井、高压管道和地面发电厂房等主要建筑物组成。首部枢纽主要建筑物由拦河坝和电站进水口组成,拦河坝为混凝土重力坝。介绍了拦河坝、坝基处理和枢纽区边坡的设计情况。工程实际运行表明,首部枢纽拦河坝设计方案合理,可为在河道狭窄、边坡陡峻的河流上建设的水利水电工程提供参考。     

EXPERIMENTAL INVESTIGATION ON THE FLOW THROUGH HANGED-PLATE OF THE TWO-STOREY INTAKE

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Redefining the Game in Local Water Management Conflict: A Case Study

The article intends to bring a new perspective on conflict and cooperation analysis addressing a case study of Yoshino river weir conflict (Japan) by the use of drama theory approach. The confrontation arose when the Governmental agency proposed to remove and replace the old weir by a movable modern dam (kodazeki) to prevent future flooding. The Opposition group’s main arguments were that the new weir may not be as effective as compared to the cost of constructing the new renewal project and damage of water quality and ecosystem. Thus, both players are playing the game where their interests are different. Rather than adopting the conventional approach of modeling the conflict using game theory, we propose the alternative approach to describe how the situation evolved and how game can be changed in the context of player’s threats and promises. This also emphasizes that future can be created cooperatively by a group, rather than by way of confrontation in the conflict. This model may bring an effective methodological leverage in conflict and cooperation analysis where we can change the game.     

Secondary Production of Highly Unsaturated Fatty Acids by Zoobenthos Across Rivers Contrasting in Temperature

Highly unsaturated fatty acids (HUFA), namely eicosapentaenoic acid (20:5n‐3, EPA) and docosahexaenoic acid (22:6n‐3, DHA), which are essential for many animals, including humans, are mainly produced in aquatic trophic webs. In fast‐flowing rivers, macrozoobenthos is the main source of HUFA for fish and may be particularly vulnerable to thermal alterations associated with climate change. We studied benthic communities in a unique natural ecosystem: the Yenisei River downstream of the dam of Krasnoyarsk Hydroelectric Power Station with very low temperature in summer because of discharge of cold water from deep in the reservoir and its tributaries with high summer temperature. This ‘natural experiment’ allowed to get rid of confounding factors, such as differences in light, seasonality, geology (biogeochemistry) and biogeography (regional species pools). As found, in spite of an increase of biodiversity and rates of daily production in warm rivers compared with cold sites, DHA and partly EPA production of zoobenthos decreased with the increase of temperature because of changes in species composition. Thus, in a climate warming context, we can predict a decrease of production of these HUFA by river zoobenthos and thereby a diminishing of their supply for fish and next to humans. Copyright © 2015 John Wiley & Sons, Ltd.     

Impacts of a weir and power station on downstream migrating Atlantic salmon smolts in a German river

Weirs are barriers built across rivers for a wide range of other purposes than hydropower production. Like hydropower installations, weirs can negatively impact fish migrations. Downstream migration and mortality of Atlantic salmon smolts were studied during passage of a weir and power station by tagging 227 smolts with radio transmitters. Extra loss of smolts due to the weir and adjacent reservoir was 5.2%. Mortality was likely related to physical damage imposed to the smolts and/or increased predation risk. Extra loss of smolts did not differ between the weir and the power station (7.2%). Migration speeds were reduced at the power station but not at the weir. We conclude that mortality at one power station site may differ considerably among years, because the mortality was more than four times higher in a previous year than in this study. Increased river discharge seemed to decrease mortality and increase migration speeds at the power station.