FISH ASSEMBLAGES RESPOND TO HABITAT AND HYDROLOGY IN THE WABASH RIVER,INDIANA

Detailed relationships between fish assemblages and habitat and hydrology variation are largely unknown for large rivers. We evaluated hydrology, habitat variation and fish assemblages at 28 sites on the Wabash River, Indiana, USA, during 2005–2008. We calculated hydrologic variation with the Indicators of Hydrologic Alteration software and tested for temporal hydrologic effects on habitat variation of substrate particle size, water depth and water velocity by reducing data into principal component axes that were tested for differences among years with ANOVAs. We then tested for effects of habitat and hydrology variation on fish assemblages with canonical correspondence analysis. These analyses showed significant relationships between hydrologic variation and local habitats, and hydrology and habitat variables had significant relationships with fish assemblage structure. Our Mantel tests resulted in significant concordance among hydrology, local habitat variation and fish assemblage structure, suggesting associations of these variables. These results supported strong connections for hydraulic control over habitat variation and subsequent effects on fish assemblages. Copyright © 2011 John Wiley & Sons, Ltd.     

POTENTIAL FOR VEGETATION‐BASED RIVER MANAGEMENT IN DRYLAND,SALINE CATCHMENTS

The approaches used to manage rivers have been developed and adapted to many different problems and settings. Because of their relatively low cost, vegetation‐based approaches implemented at the reach, landholder and catchment scales have become the foundation for river management in most landscapes. In many dryland agricultural catchments, secondary (anthropogenic) salinity caused by clearing native vegetation has resulted in rising saline groundwater, streamflow salinity values that exceed seawater and severe the degradation of riparian vegetation communities. The potential effectiveness of vegetation‐based strategies in these landscapes remains largely unknown, yet these strategies are still widely pursued. This study initially investigated the patterns of vegetation recovery and recolonization following a large flood in a saline river that disturbed the system. A conceptual model was developed to describe spatial patterns of where different vegetation types had regrown and recovered in relation to controls exerted by streamflow salinity, surface texture characteristics, topography and reach morphology. Using this model, vegetation‐based river management options for different reaches were developed, and their potential effectiveness in stabilizing reaches was investigated using a 1‐D hydraulic modelling approach. This study finds that in a dryland catchment with high stream salinity (20 000–93 000 mg L^?1), there is still a strong potential for successful vegetation‐based management, but only in selected reaches. Results showed that changes in stream power and channel velocity were not associated with the areas of most severe vegetation degradation. Rather, there is a complex interplay between channel morphology, channel slope and places of potential vegetation growth within a reach. This paper outlines an approach to evaluate the potential success of vegetation‐based river management in saline landscapes. It identifies the need to prioritize investment based on the following: an understanding of factors controlling revegetation potential, the likely impact of revegetation in mitigating adverse channel changes and the proximity of reaches to high‐value infrastructure and biodiversity assets. Copyright © 2011 John Wiley & Sons, Ltd.     

GRADIENTS IN THE BIOPHYSICAL STRUCTURE OF URBAN RIVERS AND THEIR ASSOCIATION WITH RIVER CHANNEL ENGINEERING

Urban rivers are often engineered to increase flood conveyance and stabilize channel size and position. This paper analyses habitat surveys of 180 urban river stretches of differing engineering type from four river basins (river Tame, West Midlands, UK; tributaries of the lower river Thames, UK; river Botic, Prague, Czech Republic; river Emscher, North‐Rhine Westphalia, Germany). Kruskal–Wallis tests identify significant differences in extent and/or frequency of flow types, bank and bed physical habitats, and vegetation characteristics associated with different styles of engineering. Principal Components Analysis identifies four key environmental gradients in the data set: sediment supply and retention; extent and diversity of in‐channel vegetation and riparian trees; bed and bank sediment calibre; flow type energy and complexity. These gradients discriminate stretches of differing planform, cross section and reinforcement and are significantly correlated with indices of degree and type of bank and bed reinforcement, pollution and presence of alien nuisance plant species. The analytical results illustrate statistically significant associations between different styles and levels of engineering intervention and the number and nature of physical habitats present in urban rivers. The results provide a basis for filtering sites for potential remedial measures prior to site‐specific surveys and modelling, for comparing sites and for tracking trajectories of change at sites that are subject to changes in channel engineering. They provide evidence that river condition and degree of engineering are not inversely related in a simple linear way, and that engineering of urban river channels, in the form of mixed, patchy reinforcement can contribute a great deal to habitat diversity where other controls on flow heterogeneity are more difficult to manipulate. Copyright © 2011 John Wiley & Sons, Ltd.     

山区河流船闸支墩浮式导航墙浮囤潜水渡洪

主要介绍了山区河流枢纽上游引航道外导航墙的工作条件,通过几种上游引航道外导航墙常用形式的比较,提出一种在中低水级的河床式枢纽上较为适用的支墩浮式导航墙结构形式.然而由于山区河流洪水暴涨暴落、峰谷悬殊,使得这种形式的导航墙,要么采用高大的支墩,要么渡洪时浮囤拆卸、系泊困难.为此,结合嘉陵江草街船闸的实际布置,提出了浮囤潜水渡洪的方案,既节约工程投资,又解决了渡洪问题.文中着重介绍了导航墙浮囤的主要结构及浮囤潜水渡洪的原理及过程,突出其建筑物高程低于设计洪水,汛期渡洪无须专人驻船管理的优点.     

烟台—淄博输油管道穿河工程对河道防洪影响

结合烟台港西港区至淄博重质液体化工原料输送管道穿越潍河的防洪影响评价项目,简要介绍了穿河输油管道防洪评价的基本内容和方法,对因输油管道建设对河道防洪造成的影响进行了防洪分析计算和综合评价,对影响河道防洪安全的问题提出了相应的建议。     

边界条件对自然河流形成及演变影响机理的实验研究

运用自然模型法,采用清水冲刷成功地塑造了室内天然小河。实验研究了不同的初始河流几何边界条件以及水流条件对河流演变的影响。研究发现流量对河流展宽幅值影响最大。水流入射角的大小与河流展宽幅度及河流弯曲度的变化没有必然的联系,30°入射角时小河的河流展宽及弯曲度变化最明显。入射角对河流演变的作用只是短期的,且在演变初始阶段影响较大。受初始边界条件的影响,河流向下游演变具有滞后性及曲率变化的传递性等特点。本文最后分析了河流演变过程中的泥沙分选现象。     

应用气温临界指标法在松花江依兰站预报开江日期示例

针对依兰站江段易发生冰凌卡塞、冰坝特点,采用气温临界指标法对松花江依兰站开江日期进行预报。示例列出了1962—2008年共计46 a预报结果,并作以误差分析。     

黑龙江省主要河流生态需水量的分析与研究

通过对全省21条主要江河,33个主要河段断面河道生态环境需水量估算,提出河流生态环境需水量的科学数据,为黑龙江省河流水资源的优化配置和水环境改善提供技术支持,并以此提出符合实际情况的控制措施,在今后的河流开发利用中最大限度满足河流自身生态环境用水需要。     

水文学中流域水循环机制与水文模型研究

随着社会的迅速发展,人类对自然水循环的影响越来越严重;流域内的水并非静止不动,而是处于不停地运动变化与相互变更的状态,这就要求我们要把大气、土壤及水看作一个整体或者一个系统,从而对其进行研究管理。介绍了几个较为典型的流域水文学模型,分析了现有流域水文模型的局限性,指出当前的不足及其原因。     

黄角树引水隧洞施工支洞封堵体设计

通过三维有限元计算,以黄角树引水隧洞施工支洞的实际情况为依据,选用抗剪断公式和承载能力极限状态法计算堵头在3种工况下的稳定计算比较后,从而得出堵头长度。为工程的设计提供了依据。