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The incorrect version of this article was published previously. Please find the correct version, which retains the original pagination, on the next page. The publisher wishes to apologise for this mistake Running water ecology is a young science, the conceptual foundations of which were derived largely from research conducted in Europe and North America. However, virtually all European river corridors were substantially regulated well before the science of river ecology developed. While regulation of North American river systems occurred later than in European systems, river ecology also developed later. Therefore, there is a general impression of rivers as being much less heterogeneous and much more stable than they actually are in the natural state. The thesis of this paper is that established research and management concepts may fail to fully recognize the crucial roles of habitat heterogeneity and fluvial dynamics owing to a lack of fundamental knowledge of the structural and functional features of morphologically intact river corridors. Until quite recently, most concepts in river ecology were based on the implicit assumption that rivers are stable, single‐thread channels isolated from adjacent floodplains. Unfortunately, many rivers are in just such a state, but it should be recognized that this is not the natural condition. This incomplete understanding constrains scientific advances in river ecology and renders management and restoration initiatives less effective. Examples are given of the high level of spatio‐temporal heterogeneity that may be attained in rivers where natural processes still operate on a large scale. The objective of this paper is to promulgate a broader and more integrative understanding of natural processes in river corridors as a necessary prelude to effective river conservation and management. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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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。 相似文献
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Floods during the rainy or monsoon season are typical for Thailand. Flooding occurs when a significant amount of water overflows a shoreline and floods cities and agricultural areas. Losses can be substantially reduced if the flow of the river system is managed appropriately. The objective of this work is to solve the flood forecast problem by formulating a time-varying optimization problem with ODE constraints to manage the river flow. We demonstrate our concept in the province of Ubon Ratchathani, one of the most flooded areas in northeastern Thailand. The results illustrate that our proposed method will enable operators to efficiently forecast, monitor, and operate the entire river system to mitigate flood risk. Our method is simple and computationally inexpensive, which means that it can be applied to real-time monitoring systems. Moreover, it is a generalized model that can be extended to a more complicated river system. 相似文献
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随着我国城市的发展,人们对城市河道建设提出了更多景观、亲水的要求,挡水建筑物需要既满足水利要求,又满足城市发展要求,实现与城市景观完美统一。依据研究区具体水文地质条件和河流特性选定主要评价指标,采用灰色关联分析模型对主要评价指标进行综合评价,计算各方案与理想方案的灰色加权关联度从而选择最优方案。应用实例表明,基于灰色关联分析的城市景观河道挡水建筑物比选方法有效可行。 相似文献
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城市河流景观设计之探析 总被引：34，自引：1，他引：33
基于景观环境规划设计的三元素,本文提出从安全性、自然性、生态性、观赏性、文化性、亲水性六个方面对城市河流景观效果进行分析,并简要介绍了城市河流景观设计的一些主要内容。 相似文献
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The Bagmati River, which lies in central Nepal, originates in Bagdwar at an altitude of 2690 m and flows south through the Kathmandu valley. The river basin covers an area of 3750 sq. km and includes eight districts of Nepal. Flooding along this river is a common occurrence during the monsoon season. In this study, we compared rainfall events with river discharge, predicted the rate of future flooding events, and assessed the probable causes and socioeconomic impacts of flooding in the Bagmati River Basin. Data used to compare rainfall and discharge were based on rain gauge stations with the highest 24‐h records and also contributed directly to the run‐off at the Pandhera Dobhan discharge station, the lowest elevation water discharge gauge, in order to facilitate a direct comparison between basin rainfall and river discharge. Future trends in extreme 24‐h rainfall events and peak flood values were calculated for 2‐, 5‐, 10‐, 25‐, 50‐ and 100‐year recurrence intervals. Extreme 24‐h rainfall events varied between 195 mm to 552 mm among the different rain gauges, corresponding to a peak discharge at Pandhera Dobhan of 16 523 m3/s for the 100‐year return interval. We also elaborate on the probable causes of flooding in the central basin and summarise major past flood events and their impacts. 相似文献
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An evaluation model for the rationality of the landscape design of urban rivers was established with the analytic hierarchy process （AHP） method so as to provide a foundation for updating the landscape design of urban rivers. The evaluation system was divided into four layers, including the target layer, the comprehensive layer, the element layer, and the index layer. Each layer was made of different indices. The evaluation standards for each index were also given in this paper. This evaluation model was proved tenable through its application to the landscape design rationality evaluation of the Weihe River in Xinxiang City of Henan Province. The results show that the water quality, space, activity, facility, community, width of vegetation, sense of beauty and water content are among the most influential factors and should be considered the main basis for evaluating the rationality of the landscape design of urban rivers. 相似文献
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A method is proposed and demonstrated to specify a fish community to serve as a target for planning river restoration projects and as an endpoint for evaluating programme progress. Our target fish community is appropriate for small rivers in southern New England with basins characterized by dispersed human activities. Our study was part of a multi‐agency improvement effort of the Quinebaug River in southern Massachusetts and northeast Connecticut, USA. We identify fish species expected to be found in streams, lakes and river reaches of the Quinebaug River basin. An expected rank order of abundance was computed using fish surveys from rivers identified by restoration programme managers as being in a desirable condition for a human‐dominated landscape. The rank order of species was converted to expected community proportions following a theoretical log–log relation between species abundances and occurrences in complex communities. Criteria from a committee of agency and water use representatives were influential in specifying a target community; so the overall method blends policy, objective zoogeography analyses and theory‐based parameters of community structure. We believe the use of a target community can be an important element in the design and evaluation of river restoration where the aim cannot be to copy pristine, natural ecosystem properties. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Floodplains often are managed both for agriculture and as habitat for native species. On the Sacramento River, farmers have expressed concern that natural areas may harbour small mammals in greater abundance than occurs on farms, which could make them sources of pests to adjoining farmlands. Concern over this has generated some opposition to riparian restoration. To better understand the issue, we studied small mammals at agricultural sites, young and older riparian restoration sites and remnant natural areas through live trapping and visual surveys over three successive years. Significant flooding occurred during the second winter of the study. We found that young riparian restoration sites (3–4 years since planting) did not harbour agricultural pests (e.g. California ground squirrel, Botta's pocket gopher) in greater abundance than agricultural sites, with the exception of California voles. Although voles were common at young sites, they declined dramatically as the sites matured, and neither 12‐ to 15‐year‐old sites nor remnant riparian habitats had higher abundances of any small mammal pest species than agricultural sites. All species except the arboreal western gray squirrel experienced significant population declines following the flood and remained at depressed levels for at least a full year thereafter. Native species were not less susceptible to flooding than exotic species. California vole was the first species to recover. Our study suggests that frequent winter flooding may be desirable from an agricultural pest management perspective. It illustrates a valuable ecosystem service, small mammal pest control, which is provided by flooding, an important natural disturbance process. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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‘River widenings’ are commonly used in river restoration to allow channel movement within a spatially limited area. Restoration seeks to restore fluvial processes and to re‐establish a more natural riparian community. This study investigates the performance of five river widenings in Switzerland, focusing on the re‐establishment of riparian (semi‐)terrestrial habitats and species, and highlights some factors that seem to influence their performance. The restoration projects are compared with pre‐restoration conditions and near‐natural conditions, which are assumed to represent the worst‐ and best‐case conditions along a gradient of naturalness. Fuzzy ordination of vegetation data and calculation of landscape metrics based on habitat maps revealed marked differences between the degree of naturalness achieved by each individual restoration project. However, in general river widenings were found to increase the in‐stream habitat heterogeneity and enhanced the establishment of pioneer habitats and riparian plants. Analyses of species pools based on a hierarchic list of indicator species and correspondence analysis showed that the ability of river widenings to host typical riparian species and to increase local plant diversity strongly depends on the distance to near‐natural stretches. Species dispersal and establishment might be hampered by decisions taken outside the scope of the restoration project. Therefore we conclude that action on the catchment scale is needed to maximize the benefits of local management. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Many dams in the USA have outlived their intended purpose and an increasing number are being considered for removal. Yet, quantitative studies of the potential physical, biological and ecological responses are needed to assess dam removal decisions. In this paper, the responses of migratory walleye (Sander vitreus) to increased spawning habitat availability as a result of dam removal was studied by comparing scenarios with and without a high‐head dam in the Sandusky River (Ohio), a major tributary to Lake Erie. A conceptual, ecological model was proposed to define the relationship between hydrodynamics and walleye spawning, egg hatching, larval drift and survival. A mathematical, ecological model of the early life‐history stages was then developed and coupled with time series of depth and velocity predictions over the spawning grounds from a 1‐D hydrodynamic model. Model simulations were run for 1984–1993 for both the with‐ and without‐dam scenarios to assess the potential benefit of dam removal. The simulation results demonstrated that velocity, depth and water temperature are major factors influencing adult walleye spawning success. Without the dam, 10 times the amount of spawning habitat would be available for walleye to spawn. This increase in spawning habitat area resulted in up to five times the total egg deposition and seven times the larval output to the nursing grounds, based on the assumption that 5% of the walleye population of Lake Erie migrated up the Sandusky River to spawn. We concluded that the spawning habitat in the current condition (with the dam) is limiting and additional spawning habitat upstream could significantly increase the number of larval walleye drifting to Lake Erie. The model sensitivity analysis showed that the number of walleye migrating up the river in spring is the dominant factor for larval recruitment to the lake. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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基于高精度数字高程模型（digital elevation model,DEM）数据,采用直接提取法和改进的断面构造法获得河道断面数据,将上述2种方法提取的河道断面数据作为水动力学模拟软件HEC RAS(hydrologic engineering center′s river analysis system)的主要输入,开展一维和一二维耦合水动力学数值模拟,使用实测的河道断面数据进行结果对比分析,评估不同河道断面快速获取方法的效果。将研究方法在美国佛罗里达州迈阿密河下游河段进行应用,选取2004、2014和2017年3场典型洪水,分析2种不同断面形态下洪水演进模拟结果的差异。结果表明,直接提取高精度DEM所得的河道断面数据在准确性上仍有欠缺,采用断面构造法修正后的河道断面数据模拟出的洪水水位与观测水位的均方根误差(RMSE)小于0.1 m,与实测结果十分接近,在缺少河道断面资料的地区可替代实测断面,获得可信度较好的模拟结果。 相似文献
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In order to assess the effects of river and floodplain engineering projects on flooding, a new self‐adaptive hydrodynamic scheme for the simulation of two‐dimensional river flows is proposed. The depth‐averaged motion equations are solved numerically using a fractional step method, in which the convective terms are calculated using the inverse characteristics method and the remaining terms with an explicit method based on a finite difference method. The integration is performed on a dynamically self‐adaptive calculus grid, which allows representation of the movable boundary between wetting and drying regions of the basins to follow the effective development, in time and space, of the expansion phenomenon of flood. The proposed procedure allows the grid's dynamic refinement to avoid coordinate transformation or the use of unstructured grids. The proposed method is simple and allows the thickening of the grid to accommodate the flooding phenomena on the floodplain and to calculate the velocity in the domain regions in which a higher space resolution is required. Therefore, flows running through structures such as weirs, gates, bridges or culverts can be simulated. In the paper two different case studies, approached with the proposed self‐adaptive calculation scheme, are discussed. The studies concern the analysis of the effects of structures, such as roads or embankments, on flooding phenomena in the Tiber and Tanaro basins respectively. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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This Perspective argues for an expansion of conventional concepts of river biomes to better encapsulate the emerging social understanding of ‘biomes’ as living systems with unique macro- and micro-biotic ecological and biological signatures. We approach this by firstly examining recent interpretations of river biomes that have evolved from original zonal conceptions. We then postulate on the social/public understanding on ‘biomes’ through the popularity of two rich debates: human health via gut microbiomes and soil health via the soil microbiome. With these concepts in mind, we define the river biome as ‘A living flowing aquatic ecosystem, indicative of its environmental context, comprising unique biological, ecological, hydrologic and health characteristics that shape and are shaped by macro- and micro-biotic signatures and functions’. With this definition the term river biome is more aligned with ideas of river health and ecosystem functioning, which we believe may evoke greater public understanding of rivers as complex living systems. Enhanced public understanding of complex natural systems should be encouraged as a means by which to propel policy, funding and research as well as to improve specialist to non-specialist communication and relations. 相似文献
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有关河流生态系统的恢复生态学研究综述 总被引：4，自引：0，他引：4
长久以来,人们忽略了河流的生态功能,破坏了河流的各种生态过程,导致河流污染严重、生态作用越来越小。在评述恢复生态学定义及有关认识的基础上,结合分析国内外河流生态恢复的研究现状和特点,提出在河流生态恢复中应注意的几个方面,从而达到人与自然的和谐。 相似文献