跨流域调水对生态环境的影响

本文从国内外跨流域调水工程对生态环境的改善、不良影响及防治对策进行研究。以国内外跨流域调水工程典型经验为例，说明跨流域调水工程是造福人类的重要水资源工程，对生态环境的有利影响是主要的，不良影响可以采取措施减免，生态环境效益是显著的．     

南水北调西线工程生态环境影响分析

对南水北调西线工程实施后，调水河流地区的坝址上，下游，调水工程区和受水区的自然生态环境影响及变化趋势进行了分析预测。认为：西线调水工程对大区域环境的影响，利大于弊；通过采取相应措施，生态环境方面某些潜在的不利影响可以减免。从环境角度分析，西线调水工程的兴建是可地的。     

调水工程对生态环境的影响研究综述

为了改变水资源时空分布不均的状况,调水成为缓解干旱区域水资源危机的主要途径。调水工程在带来巨大社会经济和生态环境效益的同时,必然会对生态环境产生不利影响。结合国内外调水工程的实例,分析评价了调水工程对生态环境的有利和不利影响,并针对不利影响提出了缓解和防治对策。     

国内外典型引调水工程生态环境影响分析及启示

引调水工程在缓减缺水地区水资源短缺、优化水资源配置方面有着不可取代的重要作用。在其建设和运行过程中,对生态环境造成不同程度的负面影响。文章介绍了我国引调水工程基本情况,分别从正反两方面总结了调出区、输水线路和受水区的生态环境影响。以古今中外7项引调水工程作为典型案例,总结了其对生态环境影响,提出对我国开展引调水工程生态建设和运行管理的启示。     

国外跨流域调水工程及其生态环境影响

跨流域调水是人类为改善自己的生存环境、发展经济而采取的优化水资源配置的大规模工程措施．从而获得巨大的社会、经济和生态环境效益。简要地介绍了国外已建、在建和规划设计中比较著名的跨流域调水工程，论述了国外跨流域调水工程的发展现状和建设前景，同时就跨流域调水工程对生态环境所产生的有利和不利影响进行了客观的分析评价，这对我国目前正在实施的南水北调工程有一定的借鉴意义。     

引洮供水一期工程对生态环境的影响分析

结合引洮供水一期工程对生态环境的影响分析,说明了跨流域调水工程实施前进行环境影响评价的必要性和重要性。     

跨流域调水中的生态补偿问题及其建议

跨流域调水工程已经成为解决地区水资源分布不均问题的重要手段,然而,跨流域调水工程的兴建必然会给生态环境造成影响。为促进水资源的可持续利用和生态环境的协调可持续发展,研究跨流域调水工程中的生态补偿问题具有重要意义。本文分析了5个国外著名跨流域调水工程中生态补偿的成功经验,并根据我国水资源禀赋属性,提出了建立政府主导、市场为补充的生态补偿综合机制,健全生态补偿的法律制度,优先兴建解决水质型缺水问题的跨流域调水工程,建立生态监测评估系统,在工程设计阶段考虑生态补偿,增强全社会的节水环保意识等5个方面的建议,这将为我国跨流域工程规划、设计与运行管理提供借鉴。     

美国加利福尼亚州水道调水工程

美国加利福尼亚州调水工程是美国已建成的最大调水工程，1951年州议会通过本项调水工程的规划，1961年州议会通过发行17.5亿美元公债兴建此项工程，调水工程总长为800km，其中有22座大坝，22座水泵站，6座水电站，工程分两期建设，第一期工程已于1973年完成，第二期工程在2000年前后完成，中概述了工程情况，并侧重介绍了加利福尼亚州水道上的几项关键性工程及规划设计经验，阐述了该水道工程的社会经济效益及对生态环境的影响，对我国南水北调西线工程具有借鉴作用。     

对调水工程替代措施的思考和认识

实施跨流域跨区域调水工程，需要综合考察工程造价、环境影响和社会影响等多方面因素作用，权衡利弊得失，并考虑是否有可能采取替代措施。文章分析了调水工程替代措施的内涵和范畴，着重针对再生水和海水淡化两类措施，与调水工程措施进行了优劣势对比，对其替代可行性进行分析，提出构建多水源供水保障格局应当成为共识，要在把握调水工程战略性质的前提下，认识调水工程的可替代性。     

基于大系统分解协调理论的引汉济渭调水工程受水区水资源优化配置研究

陕西省引汉济渭调水工程是近中期解决关中地区严重缺水的跨流域调水工程,如何对调水工程水资源系统进行合理运行、科学调度是急待解决的问题。本文结合引汉济渭调水工程和受水区的实际情况,在分析研究受水区供用水现状的基础上,对受水区进行供需水平衡分析,提出不同水平年引汉济渭调水工程需调水量。并以区域可持续发展为导向,采用系统分析方法,在确定的调水规模基础上,充分考虑区域的经济、社会和生态环境等因素,以供水综合效益最大为全局最优解,基于系统分析方法建立了大系统分解协调模型,对调水工程所调水量进行优化配置。     

Assessment of impact of water diversion projects on ecological water uses in arid region

In arid regions, large-scale water diversion from rivers leads to significant changes in river flow regimes, which may have large impacts on ecological water uses of river-dependent ecosystems, such as river, lake, wetland, and riparian ecosystems. To assess the integrated impact of water diversion on ecological water uses, we proposed a hierarchy evaluation model composed of four layers representing the evaluation goal, sub-areas of the influenced region, evaluation criteria, and water diversion schemes, respectively. The evaluation criteria for different types of ecological water uses were proposed, and the analytical hierarchy process was used for the integrated assessment. For a river ecosystem, the percentage of mean annual flow was used to define the grade of environmental flow. For a lake ecosystem, water recharge to the lake to compensate the lake water losses was used to assess the ecological water use of a lake. The flooding level of the wetland and the groundwater level in the riparian plain were used to assess the wetland and riparian ecological water uses, respectively. The proposed model was applied to a basin in northern Xinjiang in northwest China, where both water diversion and inter-basin water transfer projects were planned to be carried out. Based on assessment results for the whole study area and two sub-areas, an appropriate scheme was recommended from four planning schemes. With the recommended scheme, ecological water uses of the influenced ecosystems can be maintained at an acceptable level. Meanwhile, economical water requirements can be met to a great extent.     

南水北调中线工程运行的环境问题及风险分析

为使南水北调中线工程更为优质、合理地发挥作用并预防工程所带来的不利环境影响,分析讨论了中线工程水源地、总干渠以及因调水引起的汉江中下游的主要生态环境问题及潜在风险。工程水源地丹江口水库主要面临农业面源污染、重金属污染和库区消落带生态脆弱等环境问题。中线总干渠面临的主要环境问题包括藻类、贝类异常增殖和跨渠桥梁交通运输事故风险性污染,另外还存在地表水漫溢、地下水渗透和大气污染物沉降等带来的水质污染潜在风险。工程本身所引起的生态环境问题,是汉江流域中下游地区水量减少所导致的局部区域富营养化和水华。针对上述不同的环境问题,提出了应对策略和规避风险的建议。     

考虑生态流量分级约束的跨流域引水与供水优化调度研究

针对大型引水工程由于改变了河流自然流态,受水城区生产生活用水与生态环境用水矛盾突出的问题,将大伙房输水工程与大伙房水库供水联合优化调度作为典型案例,以浑江下游与大伙房水库地区用水需求、环境流态因子为优化子目标,引入3个引水比例与36个旬水库蓄水量共39个决策变量,采用遗传算法搜寻引水比例与水库蓄水量最佳解。结果表明:优化方案平均年引水量为17 242万 m³,比原计划引水量少638万 m³,对浑江流域生产生活用水、生态环境用水与大伙房水库生态环境用水之间的矛盾有显著改善;依据整体生产生活缺水与整体环境流态因子的权重,设定了多种模型子目标的权重分配组合,能够恰当地反映缺水量与环境流态因子两者间的相关性,水库调度运行管理者可以根据需要调整权重,获得满足需水条件的引水比例与水库蓄水规线。研究成果可以为大型水利工程运行管理决策提供参考。     

基于开源和节流的乌伦古河流域水库群生态调度

针对乌伦古河流域水资源短缺、灌溉挤占生态用水等问题,以生活、工业、灌溉、河道生态基流、河谷林草及补湖生态用水为调度目标,设置开源、节流方案集,建立了以生态缺水量和社会经济缺水量最小为目标的水库群生态调度模型,采用人机对话模拟优化算法求解模型。结果表明:各节流方案的河谷林草和补湖供水保证率能够满足设计要求,缓解了灌溉用水与生态用水间的矛盾,但2017现状水平年和2025远景水平年需水方案的灌溉保证率未满足设计要求;当开源+节流方案调水量超过1.0亿m³时,满足农业灌溉、河谷林草和补湖的供水保证率要求,消除了灌溉用水与生态用水间的矛盾;随着调水量超过1.0亿m³且持续增加,对河谷林草、补湖缺水量、破坏深度等影响不大,推荐1.0亿m³为最佳调水量。     

二维水流数学模型在多分汊河道鱼类栖息地设计中的应用

多分汊河道汇合或分流口水流流态复杂,常常存在河口滩及深槽,复杂多样的水文水力条件为鱼类提供了良好的进食及休憩场所。针对多分汊河道边界复杂的特点,建立了基于一般曲线坐标系下的平面二维水流数学模型。将所建立的数学模型应用于大渡河乐山段安谷水电站左岸生态河网建设和鱼类栖息地设计,对工程投运前后河段的水深、流速、流场、分流比进行模拟和对比分析,设置生态工程措施,使得鱼类产卵场河段水流特性仍满足鱼类栖息地要求。从安谷水电站运行效果看,设计的生态措施对河道鱼类栖息改善取得了较好的实践效果。     

基于图论的韩江流域水库群生态调度

采用水文学方法计算了韩江流域干支流重要控制断面的生态流量目标;基于图论原理,根据流域内干支流水系特征、重要水利工程和控制断面分布情况构建了韩江流域河网图模型;考虑河段区间来水、河道外取水、引调水等边界条件以及流域水库群水量调蓄作用,开展了河网水量平衡计算,确定了河网节点流量。通过计算水库坝址所在断面的天然生态基流,提出了耦合最小生态下泄流量要求的水库常规调度规则;借鉴大系统聚合-分解思想,提出了韩江流域河网图模型迭代优化求解思路;通过选取不同典型年来水过程,评估了常规调度情况下控制断面生态流量保障程度,并在此基础上进行优化调度,分析流域水库群生态调度保障潜力。结果显示,耦合最小生态下泄流量要求的水库常规调度规则能够让水库在独立运行的情况下,基本保障不同来水条件下的控制断面生态流量需求;韩江流域水库群可通过开展联合优化调度满足控制断面生态流量需求;基于图论方法开展流域水库群生态调度具有可行性和实用性。     

中国水利现代化和新水利理论的形成

分析在 2 0世纪中 ,中国因大规模进行水利建设而带来的流域水循环短路化、绝缘化及生态系统的孤立化等问题。并以海河流域为例 ,阐述了目前流域社会难以实现可持续发展的理由。为保证中国水利的现代化 ,必须建立新水利理论 ,在传统水利理论的基础上 ,综合考虑技术、经济、环境、生态、社会等对水系影响较大的因素 ,重新定位水利在流域可持续发展中的地位和建设目标 ,以流域为整体 ,以流域社会可持续发展为规划目标 ,不断完善新水利理论。     

EVALUATING TRADEOFFS BETWEEN ENVIRONMENTAL FLOW PROTECTIONS AND AGRICULTURAL WATER SECURITY

River basin managers responsible for water allocation decisions are increasingly required to evaluate tradeoffs between environmental flow protections and human water security. However, the basin‐scale effects of environmental flow regulations on water users are not well understood, in part because analyses are complicated by the spatial and temporal variation in water availability, human demands, and ecosystem needs. Here, we examine alternative regional environmental flow policies and their effects on a distributed network of water users in a small (182 km²) river basin in coastal California. We use a hydrologic model to simulate water diversion operations under three policy scenarios and quantify potential impacts to bypass flows for adult migrating salmon and agricultural water storage. The results indicate that there are inherent tradeoffs between environmental flows and agricultural water security, with the most restrictive environmental policy associated with the greatest impacts to water users. Surprisingly, the moderate environmental flow policy had larger impacts to bypass flows than the unregulated management scenario, suggesting that ecological benefits of the moderate policy are small relative to the adverse effects on agricultural water users. Conflicts between environmental and human water needs were greatest in upper catchments (<2.5 km²), where flow protections caused the greatest reduction in water storage. Although natural supplies were adequate for meeting water needs in most years regardless of policy restrictions, potential for conflict between environmental flow protections and water security was evident in dry years. Therefore, strategies are particularly needed for drought‐year water management to ensure adequate environmental flows while reducing human water allocations in an equitable manner. Copyright © 2013 John Wiley & Sons, Ltd.     

水利水电工程生态与环境保护的实践与展望

通过对国内外重大水利水电工程生态与环境保护实践的调研分析,提出应加强流域综合规划和规划环评,加强生态调度,建立环境友好的水利水电工程技术体系;加强河流生态保护目标研究,尽快建立水生态监测体系和生态补偿机制,并建议设立生态补偿专项基金,为各项工作提供资金保障。     

Establishing Environmental Water Requirements for the Murray–Darling Basin,Australia's Largest Developed River System

There is a global need for management of river flows to be informed by science to protect and restore biodiversity and ecological function while maintaining water supply for human needs. However, a lack of data at large scales presents a substantial challenge to developing a scientifically robust approach to flow management that can be applied at a basin and valley scale. In most large systems, only a small number of aquatic ecosystems have been well enough studied to reliably describe their environmental water requirements. The umbrella environmental asset (UEA) approach uses environmental water requirements developed for information‐rich areas to represent the water requirements of a broader river reach or valley. We illustrate this approach in the Murray–Darling Basin (MDB) in eastern Australia, which was recently subject to a substantial revision of water management arrangements. The MDB is more than 1 million km² with 18 main river valleys and many thousands of aquatic ecosystems. Detailed eco‐hydrologic assessments of environmental water requirements that focused on the overbank, bankfull and fresh components of the flow regime were undertaken at a total of 24 UEA sites across the MDB. Flow needs (e.g. flow magnitude, duration, frequency and timing) were established for each UEA to meet the needs of key ecosystem components (e.g. vegetation, birds and fish). Those flow needs were then combined with other analyses to determine sustainable diversion limits across the basin. The UEA approach to identifying environmental water requirements is a robust, science‐based and fit‐for‐purpose approach to determining water requirements for large river basins in the absence of complete ecological knowledge. © 2015 The Authors. River Research and Applications published by John Wiley & Sons, Ltd.