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1.
Reduced disturbances in regulated rivers can result in stable tree colonisation in downstream reaches. We examined spatial and temporal tree colonisation on a midstream sediment bar, focussing on three dominant taxa: Salix spp. (primarily Salix gilgiana), Robinia pseudoacacia and Albizia julibrissin. We developed allometric relationships for tree height, tree age and tree diameter at breast and knee height, as well as relationships between above and below‐ground biomass. The spatial profiles for all individual trees of these taxa were obtained before and after a major flood in September 2007. Pre‐flood data indicate that R. pseudoacacia colonize the highest elevations, A. julibrissin lower elevations and Salix spp. the lowest elevations of the three taxa. The oldest trees at each elevation were found to have survived 1.8–2.5 m inundation in past floods. Results of investigations subsequent to the flood event in September 2007 suggest that trees can survive flooding as long as their roots remain embedded in the soil. Individuals of Salix spp. experienced higher levels of inundation, but showed the greatest survival. This is probably due to morphological acclimations, particularly deep root systems and high elasticity of shoots. Considering inundation depths, erosion depths and sediment particle sizes in tree habitats, we found that sediment mobilization was the major cause of tree mortality. Thus, the ability of Salix spp. to colonize coarse sediments greatly contributed to its survival, as coarse sediments result in significantly less tractive force. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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We examined the response of nutrient concentrations to the drying and re‐flooding of ephemeral deflation basin lakes (EDBL) in western New South Wales, Australia. As lakes dried total nitrogen (TN) and total phosphorus (TP) concentrations increased. TN concentrations increased more quickly and TP concentrations increased more slowly than could be attributed to evaporation alone. This suggested that additional nitrogen was being sequestered from the atmosphere or sediments and that some phosphorus loss to the sediments was occurring. Concentrations of nitrogen oxides (NOx) and filterable reactive phosphorus (FRP), however, declined as lakes dried, suggesting a tighter coupling of nutrient release and uptake mechanisms. Inorganic nutrient concentrations rose sharply in response to re‐flooding in all lakes. Evidence is provided to suggest that post‐flood nutrient pulses are the net result of both riverine inputs and sediment releases and that the relative significance of either may be influenced by regulation. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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本文介绍了龙滩水库在华南西江水系防洪中的作用及其防洪效益和其他经济效益；简要论证比较了龙滩、大藤峡、长洲、百色水电水利项目对广西的防洪意义。 相似文献
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龙滩工程是西江水系防洪的战略工程 总被引：1，自引：1，他引：0
本文介绍了西江洪水灾害，防洪要求，洪水组成。西江水系只有龙滩水库有５０￣７０亿ｍ＾３的防洪库容，可对干流洪水进行总体控制。和下游岩滩水库联合，可对梧州洪水起巨大的削峰作用。文中重点介绍１９９４年６月特大洪水的组成，龙滩水库可能发挥的巨大作用，及对其他几次大洪水的削峰作用。 相似文献
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Onno Bokhove Mark A. Kelmanson Thomas Kent Guillaume Piton Jean‐Marc Tacnet 《河流研究与利用》2019,35(9):1402-1414
As interest mounts in nature‐based solutions (NBS) for flood mitigation as complementary options to civil‐engineering measures, possible flood‐protection strategies have become more diverse and hence complicated to assess. We offer a straightforward and educational protocol targeted for effectiveness analysis and decision making involving stakeholder participation. It is based on the concept of flood‐excess volume (FEV), the volume exceeding a threshold and generating flood damage, and explores what fraction of FEV is reduced, and at what cost, by particular flood‐mitigation measures. Quantification and interpretation of cost scenarios are facilitated using a graphical display that is easy to understand and encapsulates concepts of flood magnitude, FEV and protection‐measures efficacy. It is exemplified for two recent extreme‐flood events on the River Calder in Mytholmroyd (Yorkshire, United Kingdom) and the River Brague in Biot (Alpes‐Maritimes, France). Each case has different flood‐mitigation measures such as natural water‐retention measures, tree planting, river‐bed widening, or use of reservoirs and floods walls. Our straightforward protocol enables fast, quantifiable and easy‐to‐understand exploration of protection strategies using multiple measures, and in doing so highlights the issue of NBS scalability. 相似文献
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Kasper T. Lendering Sebastiaan N. Jonkman Mathijs van Ledden Johannes K. Vrijling 《Journal of Flood Risk Management》2020,13(Z1)
Flood risk reduction can be provided by interventions such as raising land or constructing flood defences. This paper introduces an approach to optimise the selection of risk reduction strategies. It expands existing economic optimization approaches for flood defences, by introducing (largely) analytical formulations to include the effects of approaches to mitigate flood consequences. The method considers the size of the protected area and associated damages, the costs and dimensioning of interventions and the likelihood of flooding. It is applied in several practical cases. Within the context of this economic model, we conclude that a system of flood defences is more economical than a landfill for larger areas. Fills are preferred for small areas and/or for low costs. A combination of strategies is preferred when the value protected by the flood defence is low compared to the value protected by the fill, or when the high value development is relatively small in size. The sensitivity of outcomes to the choice of the main input parameters is presented, as well as implications of the results and selection of strategies in developing and developed countries. Overall, this approach supports decision makers in developing effective strategies to manage and reduce flood risk. 相似文献
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《Journal of Flood Risk Management》2018,11(Z2):S916-S929
In Europe, floods are among the natural catastrophes that cause the largest economic damage. This article explores the potential of two distinct types of multivariate flood damage models: ‘depth‐damage’ models and ‘rainfall‐damage’ models. We use survey data of 346 Flemish households that were victim of pluvial floods complemented with rainfall data from both rain gauges and weather radars. In the econometrical analysis, a Tobit estimation technique is used to deal with the issue of zero damage observations. The results show that in the ‘depth‐damage’ models flood depth has a significant impact on the damage. In the ‘rainfall‐damage’ models there is a significant impact of rainfall accumulation on the damage when using the gauge rainfall data as predictor, but not when using the radar rainfall data. Finally, non‐hazard indicators are found to be important for explaining pluvial flood damage in both ‘depth‐damage’ and ‘rainfall‐damage’ models. 相似文献
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Marco Borga Francesco Comiti Isabelle Ruin Francesco Marra 《Wiley Interdisciplinary Reviews: Water》2019,6(2)
The last decade has witnessed the development of methodologies for the post‐flood documentation of both hydrogeomorphological and social response to extreme precipitation. These investigations are particularly interesting for the case of flash floods, whose space–time scales make their observations by conventional hydrometeorological monitoring networks particularly challenging. Effective flash flood documentation requires post‐flood survey strategies encompassing accurate radar estimation of rainfall, field and remote‐sensing observations of the geomorphic processes, indirect reconstruction of peak discharges—as well eyewitness interviews. These latter can give valuable information on both flood dynamics and the related individual and collective responses. This study describes methods for post‐flood surveys based on interdisciplinary collaborations between natural and social scientists. These surveys may help to better understand the links between hydrometeorological dynamics and geomorphic processes as well as the relationship between flood dynamics and behavioral response in the context of fast space–time changes of flooding conditions. This article is categorized under:
- Science of Water > Methods
- Science of Water > Hydrological Processes
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《Journal of Flood Risk Management》2018,11(Z2):S805-S816
Chachoengsao province is a prime shrimp producing area for domestic consumption and exports. The province, however, is often threatened by floods. Improving the effectiveness of current flood damage protection is a major challenge. This research developed a flood risk map by combining the probability of flood events and a vulnerability map based on physical characteristics of the area and socio‐economic conditions of shrimp farmers (victims). Analysis of current risk reduction measures was performed by comparing the net benefits and costs of different strategies. Damage costs to shrimp farming from flooding were also estimated for the base case (a case with no change in actions). The flood risk map shows that two‐thirds of shrimp farms are highly vulnerable to flooding when a 10‐day accumulated rainfall is greater than 250 mm which is likely to occur every 2 years. Increasing dike heights could yield higher net benefits than other flood adaptation measures. Non‐structural flood controls such as early harvesting and shifting the crop calendar are alternative measures for shrimp farmers who lack financial supports. The results show that cost‐benefit analysis based on various scenarios can help in selecting an appropriate mitigation practice especially for shrimp farms located in a high risk area. 相似文献
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对DX-3型扫描电子显微镜进行了总体维修和复杂电路图的简化。经修复和改进后的该仪器在三峡等重点工程的材料学研究工作中获得了良好的应用效果。 相似文献
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消能工的风险及经济分析 总被引：1，自引：0，他引：1
本文从经济、风险两方面论证了降低消能设施的泄洪标准后,可以取得显著的经济效益。已建工程多年来的运行经验证明了相应的破坏风险是完全可以为工程所接受的。由此,泄洪建筑物消能防冲设施的泄洪标准的降低,对节约工程投资,加速水电工程建设有较大的意义。 相似文献
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A distributed rainfall‐run‐off/flood‐inundation (DRR/FI) simulation model is developed based on a one‐dimensional dynamic wave equation for river routing and a two‐dimensional shallow water equation for surface flow simulation. The DRR/FI model can be used in different ways with the prevailing 1D pathway kinematic wave‐based distributed rainfall‐run‐off model. The DRR/FI model is designed to simulate rainfall‐run‐off processes and dike‐break/inland water inundation processes in a catchment in an integrated manner. Additionally, a direct house/crop economic loss estimation model is integrated with the DRR/FI model. With the loss estimation model, the direct house/crop economic damage within the DRR/FI model domain can be estimated in currency all at once. The DRR/FI and economic risk estimation model are applied to the Sayogawa river catchment in Japan, which experienced a severe flood disaster on 9–10 August 2009. The simulated water level/discharge and inundation area values obtained using the DRR/FI model with radar‐composite and radar‐Automated Meteorological Data Acquisition System (AMeDAS) reanalysis data are in good agreement with the observations. The results also show the range of validity obtained using raw radar data for flood forecasting. Finally, estimation of the direct house/crop economic loss has been carried out. In the results, the economic loss for houses is estimated at 23.0 billion JPY and the crop loss at 0.67 billion JPY. These estimations are in fairly good agreement with the reported values of 18.5 billion and 0.245 billion JPY. 相似文献
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黄河下游防洪形势分析 总被引：3，自引：1，他引：3
通过对实测资料、室内河工模型试验及效学模型计算结果整理，从来水来沙条件的变化、河道过洪能力、洪水演进、滩地滞洪时间及近几年洪水灾情的变化等方面，分析了当前黄河下游河道的防洪形势，希望引起有关部门的重视。 相似文献
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三峡—葛洲坝梯级枢纽常规水库调度系统是《长江三峡水利枢纽梯级水库调度自动化系统》的高级应用部分,该系统建立在三峡梯级水利枢纽水库调度自动化系统水调数据平台之上,在洪水预报成果的基础上,根据三峡—葛洲坝梯级枢纽的防洪、发电、航运的综合利用要求,作出三峡、葛洲坝电厂长、中、短期出力预报,相应作出梯级枢纽水库调度计划,确定梯级水库的蓄泄对策及闸门的开启计划,制定闸门的操作命令,完整地实现了三峡—葛洲坝梯级枢纽常规水库调度业务。 相似文献
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从我区水系分布和保障沿江两岸经济发展的情况分析，极需建设大型防洪控制工程。１９９４年广西连续多次遭受巨大的洪涝灾害，灾害损失达３６２亿元。深刻总结教训，我区水电建设应优先选择有较大防洪控制作用的项目。本文重点论述了广西江河几个大型防洪工程和水电建设的关系，并提出了开发意见和建议。 相似文献
17.
《Journal of Flood Risk Management》2018,11(Z2):S604-S615
Despite the perceived abundance of information collected after a disaster, available data furnish a narrow picture of flood impacts, or they are difficult to compare so as to produce an integrated interpretation of flood events. This is due to the diversity of the purposes for which data are collected and the variety of stakeholders involved in data collection and management. The RISPOSTA procedure addresses the need for standardised ways to collect flood damage data and to create consistent and reliable flood databases that meet the objectives of risk mitigation. In this regard, the procedure satisfies several requirements of loss data: (1) the data should refer to the different exposed sectors so as to supply a comprehensive view of flood impacts; (2) they should be collected at the finest scale so that the proper scale of analysis can be chosen by subsequent data aggregation; (3) they should be linked to the physical event as well as to the features of the different exposed elements so as to supply information on both flood impacts and their explicative variables; and (4) they should be collected at different times according to the unfolding of the event in order to describe the entire range of possible damage. 相似文献
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A multicriteria framework is developed for the selection of optimal flood mitigation and river training measures in a selected reach of Zaremroud River in Northern Iran. A river model, Hydrologic Engineering Center River Analysis System, combined with geographic information system analysis is used to simulate water levels for steady, gradually varied flow and mapping inundated flood extents. The modelling is performed for four different alternatives, considering various channel modifications with different dimensions and levee construction. Flood inundation area, flood level, flow velocity and stream power on the downstream and outside of the river bend are used as decision criteria for each alternative. Economic analysis is conducted to evaluate the cost‐effectiveness of each alternative. The decision analysis method, technique for order of preference by similarity to ideal solution, is used to compare different flood hazard mitigation measures based on risk, and environmental and economic impacts criteria. The findings of the analysis are that a levee construction at the right side of the river bank adjacent to the residential area is superior to the other three alternatives, which is confirmed using a scenario analysis of different flood mitigation measures. 相似文献
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The Bill Williams (Arizona) is a regulated dryland river that is being managed, in part, for biodiversity via flow management. To inform management, we contrasted riparian plant communities between the Bill Williams and an upstream free‐flowing tributary (Santa Maria). Goals of a first study (1996–1997) were to identify environmental controls on herbaceous species richness and compare richness among forest types. Analyses revealed that herbaceous species richness was negatively related to woody stem density, basal area and litter cover and positively related to light levels. Introduced Tamarix spp. was more frequent at the Bill Williams, but all three main forest types (Tamarix, Salix/Populus, Prosopis) had low understory richness, as well as high stem density and low light, on the Bill Williams as compared to the Santa Maria. The few edaphic differences between rivers (higher salinity at Bill Williams) had only weak connections with richness. A second study (2006–2007) focused on floristic richness at larger spatial scales. It revealed that during spring, and for the study cumulatively (spring and fall samplings combined), the riparian zone of the unregulated river had considerably more plant species. Annuals (vs. herbaceous perennials and woody species) showed the largest between‐river difference. Relative richness of exotic (vs. native) species did not differ. We conclude that: (1) The legacy of reduced scouring frequency and extent at the Bill Williams has reduced the open space available for colonization by annuals; and (2) Change in forest biomass structure, more so than change in forest composition, is the major driver of changes in plant species richness along this flow‐altered river. Our study informs dryland river management options by revealing trade‐offs that exist between forest biomass structure and plant species richness. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Marie Didier Laurent Borgniet Caroline Le Bouteiller André Evette Mireille Boyer Fanny Dommanget 《河流研究与利用》2023,39(8):1629-1638
Considered one of the five major threats to biodiversity worldwide, Invasive Alien Species (IAS) particularly threaten riparian ecosystems. Among the IAS found on riverbanks, Asian knotweeds (Reynoutria spp. including R. japonica Houtt.; R. sachalinensis [F.Schmidt] Nakai and the hybrid R. x bohemica Chrtek & Chrtkova) can barely be controlled as, once established, they disperse easily along stream banks via rhizome or stem fragments transported by water. However, the hydrogeomorphological processes underlying the establishment of Asian knotweeds are poorly understood. The objective of this study was to describe and model the hydrogeomorphological preferences of Asian knotweeds along a Mediterranean river. Based on exhaustive presence/absence surveys, we implemented two models related to the presence of Asian knotweeds: (1) at the river reach scale and (2) at the finer scale of the alluvial bar. Areas of low curvature identified as convex banks and the central parts of alluvial bars appear to be more susceptible to knotweed establishment. Highly disturbed areas were less favorable to maintaining plant species, including Asian knotweeds, while less disturbed areas with denser plant cover were more favorable to Asian knotweeds. The results seem to indicate a trade-off hypothesis in the knotweed establishment strategy between hydrogeomorphological constraints and strong interspecific competition. Analyzed in the light of the current literature, our final models are designed to integrate hydrogeomorphological processes in order to provide an operational tool to help river managers locate the areas most susceptible to knotweed invasion and with important implications for managing these species in riparian ecosystems. 相似文献