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1.
European rivers are subject to heavy demand. In this regard, hydromorphological alterations in connection with energy production or flood protection measures are among the most serious issues. Today only very few natural or near-natural river reaches remain, and in Austria only 15% of the rivers are classified as being in “very good” and a further 22% percent as being in “good” ecological condition. In keeping with the objectives of the EU Water Framework Directive, the National River Basin Management Plan defines measures intended to achieve a good ecological status and/or avoid the further deterioration of Austria’s waterbodies.  相似文献   

2.
This study applies the functional flows model (FFM) that integrates hydrogeomorphic processes and ecological functions to assess physical habitat. Functional flows are discharge values that serve ecological uses. The model was adjusted to evaluate gravel‐bed riffle functionality for fall‐run Chinook salmon with respect to river rehabilitation on the Mokelumne River and flood‐induced channel change on the Yuba River. The goal was to test if differences in ecological performance were traceable to differences in hydrogeomorphic conditions. Ecological functions studied were bed occupation (spawning, incubation and emergence) and bed preparation (river bed reworking periods)‐ both reliant on shear stress dynamics. Model outputs included number of days that have functional flows, ranges of functional flows that provide favourable sediment transport stages and the efficiency of a site to produce functional flows. Statistical significance of results was tested using non‐parametric tests. Functional flows analyses before and after geomorphic alteration indicate that river rehabilitation on the lower Mokelume River increased the number of days with functional flows, while the Yuba River May 2005 flood increased the functional ranges of flows for the test sites. Reach‐scale analyses indicated similar ecological performance at reference sites in both rivers. A comparison between both rivers showed that despite a greater geomorphic potential of the Mokelumne River sites to have functional flows, Yuba River sites actually experienced better ecological performance for fall‐run Chinook salmon freshwater life stages due to greater flow availability. The FFM provided an objective tool to assess changes in ecological functionality at hydrogeomorphically dynamic sites. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

3.
Most of the large rivers are heavily degraded and lack near‐natural conditions due to high human pressure (agricultural use and settlements) especially on former inundation areas. Hence, it is rarely possible to ‘restore’ predisturbance conditions of rivers and their floodplains. Further, river or floodplain restoration programs are often based on type‐specific reference conditions. Those reference conditions are mainly determined on the basis of historical maps not giving any information of, for example, sediment supply, flood frequency and vegetation cover (density). Especially for improving the ecological status of rivers with abandoned channel features, key habitats for target fish species have to be restored by reconnecting floodplains and their secondary channel system. In addition, because of the necessity of improving the ecological status, there is growing interest in interdisciplinary river restoration techniques. Within the presented article, an integrative concept is derived based on Light Detection and Ranging measurements and numerical modelling with respect to river dynamics (hydrologic and morphological). Further habitat modelling, based on unsteady depth‐averaged two‐dimensional hydrodynamics, is applied with a focus on the mesounit scale. For testing the conceptual model, various river reaches at the Morava River were selected, featuring different morphological characteristics. It was found that the applied management concept allows considering the important issues of river dynamics (morphological/hydrologic) using a flow‐ and flood‐pulse approach for identifying bottlenecks of target species at the Morava River. The reconnection of abandoned channels will result in an increase of hydromorphological heterogeneity and/or woody debris within the study reach. This might be of high relevance for habitat features (e.g. backwater habitats) especially for flow pulses between low flow and mean flow and/or in reaches without abandoned channels between low‐flow and the bankfull stage. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

4.
Three river conceptual models make differing predictions about the major source of primary production in lowland rivers, acknowledging the importance of primary productivity in the ecology and management of lowland rivers. Patterns of primary production in lowland rivers are still an area of considerable uncertainty. The objective of this study was to examine the major sources and transformations of organic matter in an Australian lowland river and compare them to the predictions of existing models. The broad approach adopted was to quantify the contribution from the major ecosystem components and compare these with estimates of system metabolism determined using open water measures of diel oxygen change. Three 4‐km river reaches were selected to represent the extent of variation found along the free‐flowing lowland sections of the Murray River, one of Australia's largest and most regulated rivers. Annual open water gross primary production (GPP) estimates for the Murray R. during this study ranged from 221 to 376 gC m?2 y?1 and were similar to other large rivers. Examination of the net contribution of organic matter to the channel indicates that primary productivity in the Murray R. is derived from a combination of phytoplankton, riparian vegetation and macrophytes, but that the major source varies both spatially and temporally. The present study confirms that the River Continuum Concept (RCC), the Flood Pulse Concept (FPC) and Riverine Productivity Model (RPM) all have some application to Australian lowland rivers, but that synthesis of the models will be difficult until we can incorporate the extent, causes and consequences of primary production variability. This study also highlights the importance of the microbial loop and macrophytes in the ecology of the Murray R. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

5.
Water managers and researchers strive towards the same objective: the improvement of the quality status of water bodies. However, there is still a gap between the results of academic studies on water systems and the information currently used in water management. The Water Framework Directive (WFD)‐Explorer, a modular toolbox which supports integrated water management in a river basin, attempts to bridge this gap. The toolbox analyses the impact of different restoration measures on river ecology based on expert rules embedded in this simulation environment. The strengths and weaknesses of the toolbox have been tested on the Zwalm River basin in Flanders, Belgium. The ecological status of streams in the basin spans the whole range of nearly pristine headwaters to severely impacted river stretches further downstream. Considering the key bottlenecks in the Zwalm basin and the user‐driven ecological status objectives, several water quality and physical habitat restoration options have been proposed to meet the European Water Framework Directive goals. The positive impact of restoration measures on the ecological quality ratio (EQR) for macroinvertebrates appeared to be the highest for measures affecting the nutrient inflows and thus chemical water body characteristics. However, the spatial scale on which the WFD‐Explorer modelled the impact of physical habitat restoration may have been too coarse to generate reliable results concerning such restoration measures. Hence, the combination of the WFD‐Explorer results with those of more detailed studies on physical habitat restoration impacts might be a promising approach to reliably support decision‐making implementation of the WFD. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

6.
In addition to the hydromorphological pressure on the ecological conditions of free-flowing river courses, increasing water temperature is affecting the water bodies, particularly by changing freshwater community compositions. The low discharge of numerous European rivers in the dry and hot hydrological year 2022 proves this relevance. Therefore, ecological assessment tools such as habitat modeling should take these factors into account when assessing the quantity and quality of habitats. In this paper, the habitat modeling tool “Transient River Habitat Modeling for Macrozoobenthos” (TRiMM) is improved by incorporating a fuzzy logic approach and adding water temperature to the set of parameters determining habitat suitability for macrozoobenthos. Habitat-relevant parameters, including hydromorphological factors (depth, velocity, mineral and organic substrate) and a water quality factor (temperature), are combined in the habitat model so that it can more broadly characterize river physical conditions and their interactions with biological indicators. Habitat modeling employed the mentioned parameters to simulate suitability for the macrozoobenthos in a small river in central Saxony, Germany. Due to its deteriorated condition, this river was selected as a representative for thousands of kilometers of small rivers across the region, which have been restored. The model simulated the status quo of river conditions from spring to summer for three macrozoobenthos species (Ancylus fluviatilis, Ephemera danica and Gammarus fossarum). The results showed that the natural flow resulted in dynamic habitat suitability both spatially and temporally, which differs for each species. Remarkably, the five-parameter model (depth, velocity, temperature, mineral, and organic substrate) generally performed better compared to a similar model without temperature.  相似文献   

7.
In many lowland floodplains around the world, upriver interferences to flows (weirs, dams, off‐takes) have led to much reduced frequency and duration of flooding. As a result, many floodplain wetlands are now inundated relatively rarely if at all. Given regulation of most lowland rivers in southeastern Australia, we assessed use of wetlands by birds in the essentially unregulated Ovens River in northeastern Victoria. Twelve sites (0.4–1.2 ha) were studied after flooding. Four sites were ‘permanent billabongs’, four were temporary wetlands and the other four were randomly selected woodland sites >60 m from the nearest water body (including the river) acting as ‘control’ or ‘reference’ sites. Aquatic birds were not recorded using woodland sites, but many species were differentially associated with either billabongs or temporary wetlands. A surprising number of non‐aquatic birds either exclusively or differentially were associated with wetland sites compared with woodland sites. We concluded that heterogeneous macrohabitat will increase local avian biodiversity on lowland floodplains. Moreover, densities and diversity of non‐aquatic, woodland species also increased with the presence of wetlands. Temporary wetlands were used differently from permanent billabongs by birds, especially in foraging methods. This suggests that the reinstatement of major flooding on heavily regulated floodplains would be ecologically advantageous for birds by providing foraging and breeding opportunities. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

8.
武连洲  白涛  黄强 《水资源保护》2022,38(6):168-174
在对河道生态需水特点进行分析和总结的基础上,提出了基于变化范围法和多种水文学法计算成果的河道内生态需水计算方法——下包线法,建立了考虑径流资料精度的评价体系。结合一致性审查、河道内生态需水计算和评价,构建了考虑径流非一致性的河道内生态需水计算框架,并应用于陕西省引汉济渭工程。结果表明:河道内生态需水过程具有波动性、季节性、时效性和区间性;在生态需水阈值区间内,下包线法同时满足维护河道生态和保证兴利效益的目的,可在较高生态需水标准基础上进一步压缩生态需水总量;下包线法和Tennant法中Tennant-好、Tennant-差所得生态需水过程分别为引汉济渭工程理想、适宜和最低生态需水过程。  相似文献   

9.
Extremely high river discharges in 1993 and 1995 along the Dutch rivers Rhine and Meuse have increased the public awareness of possible safety threats. As a result the ‘Space for Rivers’ program was implemented, aiming at restoring physical space for the rivers in combination with ecological rehabilitation. However, the development of species‐rich vegetation types in these floodplain areas is lagging behind restoration targets and biogeochemical constraints may play a vital role in this. Biogeochemical, hydrological and vegetation data were collected in 111 plots in both rehabilitated and original floodplains in regulated and more pristine river systems in The Netherlands and Poland. Soil nutrient and soil pore water data were summarized by factor analysis and the subsequent principal components were compared to vegetation and hydrological data by correlation analysis. The correlation analyses between vegetation parameters including nutrient stoichiometry and the biogeochemical soil variables resulted in a remarkable difference between pristine and impacted river systems. The results suggest a clear N‐limitation of plant growth in pristine floodplains, and apparent absence of limitation in regulated, impacted floodplains. In addition, results indicate that flooding events do not lead to one‐way transport of sediment and nutrients from the river into the floodplains; rather they indicate that highly dynamic hydrological conditions prevent soils from accumulating organic matter and nutrients. This study shows that nutrient limitation in regulated floodplains shifted from distinctly N‐limited plant growth to no nutrient limitation at all, probably due to decades of high fertilizer and manure application and nutrient input by the rivers during flooding. The consequence of our findings for rehabilitation activities is that it might be necessary to restore nitrogen limitation in floodplain systems in order to create opportunities for a species‐rich floodplain vegetation, through nutrient removal by hay‐making. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

10.
Colour aerial photography and multi‐spectral imagery acquired from airborne platforms for the River Tummel, Scotland, was used in conjunction with field survey to assess the feasibility of monitoring hydromorphology and human alteration within the river corridor. The study was undertaken to investigate the possibility of remotely sensing the physical status of a nation's rivers at the national scale to comply with the requirement of the European Water Framework Directive. Visual assessment and unsupervised and supervised automated classifications of the imagery were undertaken and compared with field survey data. In the absence of overhanging vegetation canopies most features above the water line of interest were visible on the imagery. Below the water line, morphology and substrate composition together with bank materials on vertically cut banks are less easily detected. The overall accuracy of automated classification procedures, compared to field survey, was 60% for the colour aerial photography and 68% for the multi‐spectral imagery. Supervised classification was superior to unsupervised classification procedures. Sun glint on water surfaces and shadows caused by high banks, trees and buildings were observed as the cause of most misclassification of features. Overall, the study demonstrates that remotely sensed digital imagery has the potential to allow panoptic mapping of river hydromorphology and human impacts. The possibilities and constraints, in light of the findings of this study, are discussed. In the context of new legislation which requires environmental protection agencies to have robust tools for monitoring the physical status, as part of meeting the objective of good ecological status, of rivers across an entire nation, remote sensing appears to provide a way forward. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

11.
For centuries, rivers have experienced massive changes of their hydromorphic structures due to human activities. The Danube River, the second largest river in Europe, is a case in point for long‐term societal imprint. Resulting human‐induced pressures are a key issue for river management, aiming to improve the ecological conditions and guarantee the provision of ecosystem services. As the most international river basin in the world, the management of the Danube is particularly challenging and needs a well‐organized cooperation of 19 nations. The recent river basin management plan has identified pollution and hydromorphological alterations as most pressing problems, but it has also acknowledged newly emerging issues. In this article, we present 3 specific examples of highly relevant issues for the future river basin management of the Danube: (a) long‐term impacts in the catchment such as changes in flood patterns and potential ecological consequences; (b) complex feedback loops linking the spread of neozoa with intertwined stressor responses due to river engineering for different purposes; and (c) linkages between different assessment approaches based on European legal frameworks to analyse the specific pressures at different spatial scales. These examples highlight the need for a more integrated approach in future Danube River Basin management schemes. Furthermore, large‐scale effects such as climate change and interactions of multiple pressures need to be addressed in future management to increase resilience of the river system and to allow a sustainable ecosystem‐based management of rivers.  相似文献   

12.
和田河干流植被生态需水量是多少?河道渗漏水量能否满足两岸植被的生态需水?为了回答这两个事关和田河中下游河道整治必要性的基础问题,本研究定量分离河道损耗水量,探究河道渗漏水量与天然植被生态需水之间的定量响应关系,结果表明:(1)多年平均来水条件下,和田河干流河损量约为6.46×10~8m~3,其中,蒸发量与渗漏量分别为3.5×10~8和2.65×10~8m~3,各占河损量的58.88%和41.12%;(2)和田河干流天然植被的生态需水量1.37×10~8m~3,河道渗漏水量可以满足植被生态水量需求。因此,本研究认为开展河道整治,不仅不会影响干流植被生态需水,还可以减少水面蒸发,提高和田河输水能力,更有利于开展生态水量调度,保护和恢复干流天然植被。  相似文献   

13.
In December 2008, the draft programmes of measures (PoM) have been published in the EU member states, which list the measures that will be taken to enhance the ecological status of surface and groundwater bodies, and to reach the environmental objectives of the EU‐Water Framework Directive (WFD). We have analysed the German PoM to identify the main pressures and the restoration measures water managers planned to implement in streams and rivers. The objective was to evaluate the PoM and to identify the main, practically relevant knowledge gaps in river management on which applied river research should focus on. In general, the selection of measures in the PoM was reasonable. In accordance with the analysis of pressures and impacts in Germany, the PoM focussed on measures addressing morphological alterations and river continuity, and the results indicated that diffuse source pollution and fine sediment input were additional main pressures in Central European streams and rivers. Although point source pollution was not a main pressure in most rivers, respective point source measures have been selected for many water bodies. Apparently, these were so‐called basic measures that have to be taken due to other EU‐Directives or national laws. Therefore, although in line with the WFD, it seemed doubtful if the point source measures would help to substantially enhance the ecological status. Furthermore, the results indicated that there was a general lack of knowledge on the effect of restoration measures and a specific knowledge gap in how to enhance the ecological state of heavily modified water bodies (HMWB) in the lowland region with a high land‐use pressure, which was reflected by the high share of water bodies for which conceptual measures have been selected (e.g. developing management plans). Based on the analysis of the PoM and a literature review, we identified the following, practically relevant knowledge gaps in river management: (i) the morphodynamics of river reaches where natural channel dynamics have been restored, (ii) the combined effect of measures addressing diffuse nutrient and fine sediment input at different spatial scales (e.g. riparian buffer strips and land‐use changes), (iii) methods to identify suitable and efficient measures and to define environmental objectives for HMWB and (iv) the effect of measures on less well‐studied biological groups like macrophytes and phytoplankton. There is a strong need to summarize recent research results on these issues, to identify the knowledge gaps and research needs in detail, and to make the results of such a comprehensive literature review or meta‐analysis available for the next 6‐year management cycle and second WFD management plans. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

14.
For many years, navigable lowland rivers have been embanked artificially or suffered from substantial shipping wave action, leading to habitat degradation. Recently, riparian habitats were restored by creating foreshores and spawning grounds in the river Yser, a lowland river in Flanders, Belgium. The aim of this paper was to evaluate the role of these restored habitats for spawning and nursery of juvenile fish. To cover a wide range of anthropogenic disruption, four riparian mesohabitat types were selected and compared, ranging from semi‐natural over artificial spawning grounds and foreshores to artificial embankments. Juvenile fish were subjected to sampling by using electrofishing between June and September 2009 at different microhabitats located in five sites of each riparian mesohabitat type. Juvenile fish strongly preferred natural riparian habitats, whereas artificial embankments showed the lowest species richness, abundance and functional organization of juvenile fish species. Restored riparian habitats appeared to be an appropriate alternative for artificial embankments in navigable lowland rivers but still score significantly less than natural habitats. Juvenile fish avoided bare microhabitats but did not prefer any other microhabitat type (reed, woody or grassy vegetation), emphasizing the importance of microhabitat diversity. This paper provides valuable insights into riparian habitat restoration to river managers and stakeholders. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
River surveys are undertaken for a variety of purposes including (i) to establish inventories of particular features and their changes, (ii) to collect data to underpin the classification of river types or to assess resources according to particular criteria, and (iii) to identify sites that have particular qualities or may require particular types of management. In this paper we describe a new reach‐scale survey technique, a range of synthetic indices, and a series of classifications specifically developed for application to urban rivers. The Urban River Survey (URS) is developed from the River Habitat Survey (RHS) which is applied routinely to UK rivers. A number of important differences between the URS and RHS allow the former to provide improved discrimination between urban river channels to support management decision‐making. Urban river stretches are identified for survey according to their engineering type (a combination of planform, cross‐sectional form and level of reinforcement). The URS is then applied to stretches of a single engineering type and incorporates recording of (i) additional variables to the RHS that are particularly relevant to urban channels (e.g. indicators of pollution); (ii) improved resolution in the recording of some variables in comparison with the RHS (e.g. habitat features); and (iii) separation of layers of information that relate to the engineered (e.g. artificially introduced materials) and more natural (e.g. bank materials and morphological features) channel properties so that the interaction between these properties can be identified. The URS is applied during two surveys of approximately 50 stretches of the River Tame, West Midlands, UK. The data are used to estimate a range of synthetic indices describing ‘Materials’, ‘Physical Habitat’ and ‘Vegetation’ attributes of urban river stretches. Cluster analysis is then applied to these indices to derive three classifications of urban river stretches. The similarity in classifications based on measurements from two different surveys indicates their robustness. Because the type of engineering applied to a stretch appears to have a significant influence on the class to which the stretch is allocated in each of the three classifications (with the strongest associations being apparent in the Materials classes and the weakest in the Vegetation classes), they can be used to explore the consequences of changed engineering, and the influence of scenarios of vegetation and water quality management can be additionally explored in relation to the Vegetation classification. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

16.
河流分类是认识河流形成、发育、演变、发展规律以及开展河流系统保护、治理及修复的基础。针对河流系统研究的具体目标,过去已经从不同角度提出了多种河流分类方法。随着人们对河流系统认识的深入,在新的历史时期亟需面向生态的河流分类方法。本文结合河流分类的现有成果,基于对河流生态系统形成背景和结构特征的深入分析,提出了河流综合分类方法体系和多尺度编码方法,从河流的纪、系、统、类、型、境、群多个层次探讨了不同时空尺度上影响河流行为的环境因子及其生态响应关系,系统地阐述了现有分类方法在综合分类体系中的地位和作用,揭示了目前各分类方法之间的关系及其合适的应用范围,并进一步探讨了典型生境条件下生物群落结构组成及其时空分布特征,为指导河流系统保护、环境治理和生态修复提供科学依据。  相似文献   

17.
The effects of restoration of channel meandering and of groyne structures on physical variables and river‐dwelling macroinvertebrates were examined in a lowland river, the Shibetsu River in Northern Japan. The lowland segment of the Shibetsu River, which previously meandered, was straightened by channelization and groynes installed on some portions of the channelized reach. In 2002, the channelization works were partly reversed to improve the degraded river ecosystem. Physical environment variables and macroinvertebrate community structure and composition were compared among reconstructed meanders and channelized reaches with and without groynes. The shear stress of the river edge in reconstructed meanders and groyne reaches was lower than that in a channelized reach. In addition, the edge habitat near the stream bank created by the reconstructed meander and groyne reaches had higher total density and taxon richness of macroinvertebrates than those of the channelized reach. Restoration provided a relatively stable edge habitat, contributing to the recovery of macroinvertebrate communities in such channelized lowland rivers. The placement of groynes can be an effective method of in‐stream habitat restoration for macroinvertebrates. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

18.
Benthic macroinvertebrates were quantitatively sampled from thirty sites along two river systems in southwestern Australia, and patterns in community structure related to physical and chemical parameters. Classification and ordination showed a major separation between upland and lowland sites, irrespective of river system. The change in benthic community structure reflected the rapid transition in geomorphology, stream hydraulics, and water chemistry as upland forested streams exit the Darling Escarpment to give rise to open rivers, disturbed by agriculture and urban development. One upland site was clearly influenced by a storage reservoir immediately upstream and consistently grouped with lowland sites; evidence of recovery was apparent at sites downstream. The remaining upland sites were separated on the basis of catchment; this was most likely related to stream flow permanence than any inherent catchment difference. A seasonal pattern was also detected for upland sites. Samples taken in summer or autumn were distinct from those taken in winter or spring. In constrast, lowland sites could not be separated into distinct groups on the basis of season or drainage basin. The presence of cosmopolitan and tolerant species with a high likelihood of dispersal, together with the homogeneous nature of the sites, may account for the high degree of similarity among benthic communities of sites along the lowland rivers. Much of the spatial and temporal variation in benthic community structure was explained by physical characteristics of the sites. Prediction of community type using chemical data alone was poor, however, this success could be improved by combining physical and chemical data, particularly for upland sites. The poor predictive success using chemical data was likely the result of the abrupt changes in the physical nature of the streams, and the absence of large spatial differences in water quality. The successful predictive relatioship betweenm benthic community structure and physical data will enable water management authorities to detect subsequent changes in water quality in these two river systems. The predictive power of the model could be assessed in adjacent river systems for which the patterns in benthic community structure are as yet unknown.  相似文献   

19.
河湖健康评估是河湖生态保护管理的重要基础性技术工作,是全面推行河(湖)长制建设的重要任务。本文重点介绍全国河湖健康评估工作的技术成果,主要内容包括:构建了包括水文水资源、河湖物理形态、水质、水生生物及河湖社会服务功能五个方面的健康评估指标体系,提出了5个等级的河湖健康分级标准,形成了系统的河湖健康调查评价方法,采用该标准与方法,在全国36个河湖(库)水体进行了河湖健康评估。实践证明,全国河湖健康评估提出的河湖健康内涵及评估指标体系能够系统表征我国河湖生态及功能特点,指标总体科学合理,整套技术方法具有很好的操作性。  相似文献   

20.
为评价长江下游平原河网地区生态护岸对河流生态系统的影响,构建了生态护岸对河流生态系统影响评价指标体系。根据生态护岸对河流生态系统的影响方式以及健康河流的特征,提出以水质状况、生物状况、水文特征、地貌特征和社会经济5个方面作为评价指标体系的准则层;采用频度分析法和相关性分析法,对现有关于生态护岸、河流生态系统评价等的研究成果进行分析,筛选出18项关键指标;提出了指标赋分、生态护岸综合影响指数计算方法以及影响等级标准,可用于长江下游平原河网地区生态护岸建设的评价。  相似文献   

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