Effects of regulation on the flow regime of the river Murray,Australia

The flow regime of the River Murray has changed markedly over the last century, and especially the last 50 years, through increased diversions, construction of dams, weirs and levees and changes in operational procedures. A model developed by the Murray–Darling Basin Commission is used to compare simulated natural (unregulated) flows at eight stations with those at seven consecutive stages in the development of regulation. Monthly and annual average flows and coefficients of variation and skewness were computed, and the flow-duration, peak-flow and low-flow characteristics curves plotted. The results confirm that average monthly and annual flows are now considerably lower than those which prevailed under natural conditions. The seasonal distribution of flows has changed in the upper Murray, owing to the influence of dams. Flow-duration characteristics now vary considerably along the river, whereas there was little change under natural conditions. The effect of regulation on flow-duration characteristics is minimal at Albury and becomes more pronounced downstream; it is most apparent in regard to flows exceeded 20–80% of the time. The magnitude of average annual floods (annual exceedance probability 50%) has been reduced by over 50% at all stations, but big floods (average recurrence interval 20 years or more) are little affected. Further, the low flows for a given annual non-exceedance probability are higher under regulated conditions than those under natural conditions. These changes have profound implications for communities of native plants and animals in both riverine and floodplain environments, and also for the long-term utility of the river as a resource.     

WEIR POOL SURCHARGE AND A CORRESPONDING INCREASE IN ALGAL BIOFILM COMMUNITY DIVERSITY IN THE LOWER RIVER MURRAY,SOUTH AUSTRALIA

Lowland rivers impounded by weirs are often operated to provide stable water levels. In the lower River Murray, stable water levels promote algal biofilms dominated by stalked diatoms, filamentous green algae and Cyanobacteria. In summer 2005–2006, the Lock 5 weir pool was surcharged for environmental benefit. Algal biofilms grown on artificial substrates were compared to the following year when the water level remained stable. On both occasions, substrates were fixed at 300‐mm depth in the river channel and a connected wetland. During the surcharge, additional floating substrates were deployed to control for the change in water level. The algal communities that developed during both years were dominated by diatoms. A greater diversity in the biofilm community was evident during the 4‐month surcharge when compared with the following year. This was due to a much greater change in algal biofilm community composition over the 4 months of the surcharge, compared with biofilms grown during a period of stable water level, when the community changed little after 1 month. The lack of difference between fixed and floating substrates suggests that the change in water level was not responsible for the difference between the surcharge and stable level biofilms. Possible reasons for the difference between years include light, nutrients and water temperature. Although the effect of the surcharge could not be definitively defined, these results provide some evidence that weir pool surcharge may be used to improve algal biofilm diversity when compared with the current stable water level regime. Copyright © 2011 John Wiley & Sons, Ltd.     

Temporal changes in macroinvertebrate assemblages following experimental flooding in permanent and temporary wetlands in an Australian floodplain forest

The River Murray, Australia, is a highly regulated river from which almost 80% of mean annual flow is removed for human use, primarily irrigated agriculture. Consequent changes to the pattern and volume of river flow are reflected in floodplain hydrology and, therefore, the wetting/drying patterns of floodplain wetlands. To explore the significance of these changes, macroinvertebrate samples were compared between permanent and temporary wetlands following experimental flooding in a forested floodplain of the River Murray. Weekly samples from two permanent wetlands and four associated temporary sites were used to track changes in macroinvertebrate assemblage composition. Non‐metric multidimensional scaling was used to ordinate the macroinvertebrate data, indicating consistent differences between the biota of permanent and temporary wetlands and between the initial and later assemblages in the temporary sites. There were marked changes over time, but little sign that the permanent and temporary assemblages were becoming more alike over the 25‐week observation period. The apparent heterogeneity of these systems is of particular importance in developing river management plans which are likely to change flooding patterns. Such plans need to maintain a mosaic of wetland habitats if floodplain biodiversity is to be supported. Copyright © 2002 John Wiley & Sons, Ltd.     

探索中国推进流域综合管理的发展路线图

简单讨论了中国推进流域综合管理的必要性,分析了实施流域综合管理的障碍和不利因素,提出了流域综合管理的愿景及基本框架,认为中国的流域综合管理需要采取符合国情和流域管理趋势的渐进式路径,同时探讨了实现流域综合管理的流域立法、流域管理机构、流域治理技术的发展路线图及其优先行动,以期最终实现流域的可持续发展。     

气候变化对乌裕尔河流域水文特性的影响

对两参数月水量平衡模型进行改进,加入融雪径流模块,经验证,模型适用于乌裕尔河流域。建立了以最高气温、最低气温、降雨和风速为变量的蒸发皿蒸发估算模型,实现了气候模型结果与水文模型的连接。利用CS IRO-M k2和CCSR/N IES两个模型模拟结果加权平均,模拟未来气候变化,探讨了水文要素对气候变化的响应。结果表明:在未来四种温室气体排放情景(SRES A 1,A 2,B 1,B 2)下,最高气温、最低气温和降水呈显著的上升趋势,而风速则呈显著下降趋势;径流深和径流系数在四种情景下都有显著上升趋势,置信水平排序为A 2>A 1>B 1>B 2;敏感性分析和趋势检验结果证明了降水是影响径流的最主要因素。     

对流域规划中系统性融资方案的思考

流域治理工程投资巨大,需要以政府投资为主导,并吸引社会投资,因此在流域规划研究中,有必要加强政府投资与市场融资的有效机制研究。阐述了在流域规划研究工作中,加强投融资研究的重要性和必要性,建议规划研究和制定部门应加强与金融机构的合作,制定系统性融资方案,以增强政府融资能力和解决融资途径,确保规划目标实现。介绍了国家开发银行在推动政府规划先行、进行市场机制和信用建设,从而为规划实施提供融资支持方面所积累的一些经验。     

汉江上游流域水文特性分析

通过安康长系列水文资料分析，论述了汉江上游流域内降水、径流、泥沙的变化规律，同时提出了暴雨洪水特性、水力资源有效利用两个主要问题。     

CHHMS耦合模型在河流生态修复中的应用

针对伊利诺伊河流域的Emiquon区域以及肖托夸湖泥沙淤积问题。运用CHHMS耦合模型(Coupled Hydrology and Hydraulics Model System)对研究区域在不同泄洪开口组合的泥沙分布进行模拟,并根据不同流速状态下的颗粒流线图进行模拟得到沉淀物分布状况,结合湿地植物及鱼类生长需求对结果进行分析。研究发现CHHMS耦合模型在河流生态修复的模拟运用中具有很高的可开发性和实用性,经过模型模拟得到研究区域的合理规划方式,并且在成功利用河流到蓄滞洪区开口的情况下,水量以及泥沙沉淀物得到有效的控制,植被得到恢复,湿地的生态状况得到有效的改善。     

长江科学院河流专业研究进展综述——以《长江科学院院报》30年来发表的论文为例

以长江科学院河流研究所20世纪80年代以来发表在《长江科学院院报》上的论文为基础,概述了近30 a来紧密结合长江流域综合规划、重大水利工程建设、长江河道治理方略等方面开展的有关长江河流泥沙、河道治理及河流模拟研究的主要工作成果。可见,30 a来长江科学院河流研究所在长江泥沙运动基本规律、河流动力学的学科交叉发展、河流物理模型基础理论、河流数学模型基本方法以及典型河段治理工程经验等方面的研究取得了长足进展,为长江河道治理、重大水利工程建设提供了大量的科学依据。并认为在未来一段时间,还需更进一步探索长江流域宏观泥沙问题、深入研究长江流域细观泥沙问题、突出长江河道与湖泊的综合治理等,才能更好地服务于更大范围和更高目标的治江事业。