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1.
Flood occurrence has always been one of the most important natural phenomena, which is often associated with disaster. Consequently, flood forecasting (FF) and flood warning (FW) systems, as the most efficient non-structural measures in reducing flood loss and damage, are of prime importance. These systems are low cost and the time required for their implementation is relatively short. It is emphasized that for designing the components of these systems for various rivers, climatic conditions and geographical settings different methods are required. One of the major difficulties during implementing these systems in different projects is the fact that sometimes the main functions of these systems are ignored. Based on a systematic and practical approach and considering the components of these systems, it would be possible to extract the most essential key functions of the system and save time, effort and money by this way. For instance, in a small watershed with low concentration and small lead time, the main emphasis should be on predicting and monitoring weather conditions. In this article, different components of flood forecasting and flood warning systems have been introduced. Then analysis of the FF and FW system functions has been undertaken based on the value engineering (VE) technique. Utilizing a functional view based on function analysis system technique (FAST), the total trend of FF and FW functions has been identified. The systematic trend and holistic view of this technique have been used in optimizing FF and FW systems of the Golestan province and Golabdare watersheds in Iran as the case studies.  相似文献   

2.
《Comptes Rendus Geoscience》2005,337(1-2):203-217
Advances in flood forecasting have been constrained by the difficulty of estimating rainfall continuously over space, for catchment-, national- and continental-scale areas. This has had a concomitant impact on the choice of appropriate model formulations for given flood-forecasting applications. Whilst weather radar used in combination with raingauges – and extended to utilise satellite remote-sensing and numerical weather prediction models – have offered the prospect of progress, there have been significant problems to be overcome. These problems have curtailed the development and adoption of more complete distributed model formulations that aim to increase forecast accuracy. Advanced systems for weather radar display and processing, and for flood forecast construction, are now available to ease the task of implementation. Applications requiring complex networks of models to make forecasts at many locations can be undertaken without new code development and be readily revised to take account of changing requirements. These systems make use of forecast-updating procedures that assimilate data from telemetry networks to improve flood forecast performance, at the same time coping with the possibility of data loss. Flood forecasting systems that integrate rainfall monitoring and forecasting with flood forecasting and warning are now operational in many areas. Present practice in flood modelling and forecast updating is outlined from a UK perspective. Challenges for improvement are identified, particularly against a background of greater access to spatial datasets on terrain, soils, geology, land-cover, and weather variables. Representing the effective runoff production and translation processes operating at a given grid or catchment scale may prove key to improved flood simulation, and robust application to ungauged basins through physics-based linkages with these spatial datasets. The need to embrace uncertainty in flood-warning decision-making is seen as a major challenge for the future. To cite this article: R.J. Moore et al., C. R. Geoscience 337 (2005).  相似文献   

3.
中国城市洪涝问题及成因分析   总被引:6,自引:0,他引:6       下载免费PDF全文
随着经济社会的发展,中国步入城镇化快速发展的阶段,城镇化率已由2000年的36.22%增加到2014年的54.77%。在全球气候变化与快速城镇化背景下,中国城市洪涝灾害日益严重。阐述了全球气候变化及城镇化对城市降水和极端暴雨的影响机制,并从流域产汇流角度分析了城镇化对洪水过程的影响,系统剖析了中国城市洪涝频发的主要原因。在成因分析的基础上,进一步提出了中国城市洪涝防治的应对策略,主要包括:①以低影响开发理念为指导,加强城市基础设施建设,建设海绵城市;②建立城市洪涝立体监测、预报预警和实时调度系统,强化城市洪涝科学决策能力;③健全和完善城市洪涝应急预案,强化应急管理能力,完善灾害救助和恢复机制。  相似文献   

4.
An agent-based model for risk-based flood incident management   总被引:3,自引:1,他引:2  
Effective flood incident management (FIM) requires successful operation of complex, interacting human and technological systems. A dynamic agent-based model of FIM processes has been developed to provide new insights which can be used for policy analysis and other practical applications. The model integrates remotely sensed information on topography, buildings and road networks with empirical survey data to fit characteristics of specific communities. The multiagent simulation has been coupled with a hydrodynamic model to estimate the vulnerability of individuals to flooding under different storm surge conditions, defence breach scenarios, flood warning times and evacuation strategies. A case study in the coastal town of Towyn in the United Kingdom has demonstrated the capacity of the model to analyse the risks of flooding to people, support flood emergency planning and appraise the benefits of flood incident management measures.  相似文献   

5.
Improving the accuracy of flood prediction and mapping is crucial for reducing damage resulting from flood events. In this study, we proposed and validated three ensemble models based on the Best First Decision Tree (BFT) and the Bagging (Bagging-BFT), Decorate (Bagging-BFT), and Random Subspace (RSS-BFT) ensemble learning techniques for an improved prediction of flood susceptibility in a spatially-explicit manner. A total number of 126 historical flood events from the Nghe An Province (Vietnam) were connected to a set of 10 flood influencing factors (slope, elevation, aspect, curvature, river density, distance from rivers, flow direction, geology, soil, and land use) for generating the training and validation datasets. The models were validated via several performance metrics that demonstrated the capability of all three ensemble models in elucidating the underlying pattern of flood occurrences within the research area and predicting the probability of future flood events. Based on the Area Under the receiver operating characteristic Curve (AUC), the ensemble Decorate-BFT model that achieved an AUC value of 0.989 was identified as the superior model over the RSS-BFT (AUC = 0.982) and Bagging-BFT (AUC = 0.967) models. A comparison between the performance of the models and the models previously reported in the literature confirmed that our ensemble models provided a reliable estimate of flood susceptibilities and their resulting susceptibility maps are trustful for flood early warning systems as well as development of mitigation plans.  相似文献   

6.
Marc Zaugg 《GeoJournal》2002,58(4):275-284
Resulting in part from massive floods in the 1970s, 1980s and 1990s, the institutional framework structuring flood protection in Switzerland has undergone considerable changes. This can be described as a `change in philosophy' – a term meant to express the change from a primarily technologically oriented `expert system' to one committed to the concept of sustainability. Sustainability, though, calls for the coordination of many expectations. Therefore, flood protection projects are today often negotiated against the backdrop of conflicting interests and are usually associated with a substantial change of the existing rules regarding the use and protection of a stretch of running water and its spatial environment. Nowadays, different actors from diverse social and state levels are participating in these conflicts about territoriality and scale. This article illustrates such a negotiation process using the example of a specific flood protection project on the River Thur in Eastern Switzerland.  相似文献   

7.
Hydrogeomorphic methods for the regional evaluation of flood hazards   总被引:1,自引:0,他引:1  
The “upstream” approach to flood hazard evaluation involves the estimation of hydrologic response in small drainage basins. This study demonstrates the application of geomorphology to such studies in a region of unusually intense flooding in central Texas. One approach to flood hazard evaluation in this area is a parametric model relating flood hydrograph characteristics to quantitative geomorphic properties of the drainage basins. A preliminary model uses multiple regression techniques to predict potential peak flood discharge from basin magnitude, drainage density, and ruggedness number. After mapping small catchment networks (4 to 20 km2) from remote sensing imagery, input data for the model are generated by network digitization and analysis by a computer-assisted routine of watershed analysis. The study evaluated the network resolution capabilities of the following data formats: (1) large-scale (1:24,000) topographic maps, employing Strahler's “method of v's”, (2) low altitude black-and-white aerial photography (1:13,000 and 1:20,000 scales), (3) NASA-generated aerial infrared photography at scales ranging from 1:48,000 to 1:123,000, and (4) Skylab Earth Resources Experiment Package S-190A and S-190B sensors (1:750,000 and 1:500,000 respectively). Measured as the number of first order streams or as the total channel length identified in small drainage areas, resolution is strongly dependent on basin relief. High-density basins on the Edwards Plateau were poorly depicted on orbital imagery. However, the orbital network definition of low-relief basins on the inner Texas Coastal Plain is nearly as accurate as results from large-scale topographic maps. Geomorphic methods are also useful for flood hazard zonation in “downstream” flood plain areas. Studies of the Colorado River valley near Austin, Texas, easily distinguished infrequent (100- to 500-year recurrence interval), intermediate (10- to 30-year), and frequent (1- to 4-year) hazard zones. These mapping techniques are especially applicable to the rapid regional evaluation of flood hazards in areas for which there is a lack of time and money to generate more accurate engineering-hydraulic flood hazard maps.  相似文献   

8.
The Yamuna flood plains spread across the northern part of Indian subcontinent is home to millions of people. The ever-growing population in these plains make it difficult to sustain the demand of freshwater resources. However, the productive aquifers of flood plains could provide solution for these issues. In this context, it is necessary to understand the aquifer characteristics. Thus, the paper attempts to characterize the aquifer in Palla area of the flood plain using integrated approach. Besides, grain size analysis and site-litholog study, the nature of aquifer material was also ascertained from bulk mineralogy of the sediments using X-Ray Diffraction. The aquifer parameters were estimated with help of long duration pumping test data. Moreover, the effect of pumping on salinity variation and hydrochemical facies evolution was also examined. The sand dominant, unconfined aquifer was estimated to have horizontal hydraulic conductivity in the range of 25 m/day and vertical hydraulic conductivity of 6–7 m /day. While the specific yield of the aquifer was estimated in the range of 0.07–0.08. It is observed that under conducive active flood plain environment, the given sand mineralogy at the site does not allow salinity increase in groundwater even after more than a decade of groundwater pumping. In fact, over years, hydrochemical facies have evolved towards Bicarbonate type. These things put together make the active flood plain aquifer a sustainable groundwater resource.  相似文献   

9.
Geomorphological zoning for flood inundation using satellite data   总被引:3,自引:0,他引:3  
The authors investigated geomorphological features on the central plain of Thailand utilizing satellite remote sensing data and made geomorphological land classification map showing flood-stricken area. Land classification maps showing flood-striken area tell us former flood inundation area, such as inundation depth, inundation width, flood flow course and flood direction, as well as estimating of the features of flooding. Thus map is useful for planning of flood control works.We classified land form units in the central plain of Thailand as following; delta, tidal flat, lagoon, mud spit, back marsh, natural levee, fan and former river course and so on. After that, the principal component analysis is applied to Landsat TM data and gives good results for photo interpretation of land form units and we transfer geomorphological land classification map to make zoning map of flood risk for the purpose of evaluating the flood damages.  相似文献   

10.
Flash floods are one of the major natural hazards occurring in small streams with a negative effect on the country as well as on human lives. Heavy rainfall occurred on July 20, 2014 and July 21, 2014 and caused severe surface water flooding and a flash flood in the Malá Fatra National Park (Slovakia). The most affected was Vrátna Valley with the Varínka stream. This study presents a reconstruction and post-event analysis of a flash flood on small ungauged basin located in this protected area of Slovakia. The reconstruction included hydraulic terrain measurements on estimating the flood’s culmination and documenting the flood’s development. The measurements were taken at three cross sections of the Varínka stream. This paper is focused mainly on post-event analysis of the Varínka stream in two profiles: Strá?a (gauged profile) and Tiesňavy (ungauged cross section). Subsequently, the extremeness of the flash flood was preliminary evaluated. Results of the post-event analysis showed that the July 2014 flood was not the highest flood in this area despite its catastrophic consequences. By studying historical materials, we came to the conclusion that in the past (e.g. in 1848 or 1939) some devastating floods in this area had occurred, which had disastrous consequences for the population. The second part of the study is focused on comparing this flash flood with three major floods which have occurred in Slovak territory since 1998. The first flood occurred on the 20th of July, 1998 on the Malá Svinka stream, and the two others are floods which occurred on the 7th of June, 2011 in the Small Carpathian Mountains: on the Gidra stream in Píla village and on the Parná stream in Horné Ore?any village. Such comparison of flash floods from different geographical regions and different rainfall events can provide comprehensive information about their regimes, threats and disastrous effects.  相似文献   

11.
Understanding and improving the public perception has become an important element in the management of flood risk worldwide. In Iceland, studying perception of flood hazard and flood risk is, however, in its early stages. This paper presents a case study on the public perception of flood hazard and flood risk in an Icelandic town prone to ice-jam floods. Awareness of the population regarding historical inundations, self estimation of flood risk and worry is considered. The factual knowledge of the residents is deconstructed in flood hazard parameters accessible to the lay population: number of events, dates, genesis and boundaries. The performance of the respondents is rated for each parameter and the influence of several predictors evaluated. The research shows three significant patterns: there is poor awareness and little worry about historical inundations in the area; experience of the past flooding events in town is the most effective source of knowledge; awareness, risk estimation and worry are not correlated.  相似文献   

12.
Flood hazard increasingly threatens human communities that occupy floodplains. Economic planning of control measures relies on identification and prioritization of the flood source areas in the watershed draining to the threatened reach. Distribution of flood control activities in proportion to the priority of flood source areas can reduce excessive costs and increase flood control efficiency. In this research, a distributed Clark-based rainfall-runoff model in conjunction with a hydrologic routing model was calibrated and validated in the watershed of interest. Then, a 2 * 2 km2 discretization scheme was implemented to represent some 200 pixels for flood source identification. The unit flood response (UFR) approach was then carried out at pixel scale. This step resulted in, for the first time, a distributed flood index map, which identifies and ranks pixels with high impact on the flood regime of the flood-threatened reach. The iso-flood severity map can be also extracted in a contour format.  相似文献   

13.
Flash flood disaster is a prominent issue threatening public safety and social development throughout the world, especially in mountainous regions. Rainfall threshold is a widely accepted alternative to hydrological forecasting for flash flood warning due to the short response time and limited observations of flash flood events. However, determination of rainfall threshold is still very complicated due to multiple impact factors, particular for antecedent soil moisture and rainfall patterns. In this study, hydrological simulation approach (i.e., China Flash Flood-Hydrological Modeling System: CNFF-HMS) was adopted to capture the flash flood processes. Multiple scenarios were further designed with consideration of antecedent soil moisture and rainfall temporal patterns to determine the possible assemble of rainfall thresholds by driving the CNFF-HMS. Moreover, their effects on rainfall thresholds were investigated. Three mountainous catchments (Zhong, Balisi and Yu villages) in southern China were selected for case study. Results showed that the model performance of CNFF-HMS was very satisfactory for flash flood simulations in all these catchments, especially for multimodal flood events. Specifically, the relative errors of runoff and peak flow were within?±?20%, the error of time to peak flow was within?±?2 h and the Nash–Sutcliffe efficiency was greater than 0.90 for over 90% of the flash flood events. The rainfall thresholds varied between 93 and 334 mm at Zhong village, between 77 and 246 mm at Balisi village and between 111 and 420 mm at Yu village. Both antecedent soil moistures and rainfall temporal pattern significantly affected the variations of rainfall threshold. Rainfall threshold decreased by 8–38 and 0–42% as soil saturation increased from 0.20 to 0.50 and from 0.20 to 0.80, respectively. The effect of rainfall threshold was the minimum for the decreasing hyetograph (advanced pattern) and the maximum for the increasing hyetograph (delayed pattern), while it was similar for the design hyetograph and triangular hyetograph (intermediate patterns). Moreover, rainfall thresholds with short time spans were more suitable for early flood warning, especially in small rural catchments with humid climatic characteristics. This study was expected to provide insights into flash flood disaster forecasting and early warning in mountainous regions, and scientific references for the implementation of flash flood disaster prevention in China.  相似文献   

14.
Estimating Injury and Loss of Life in Floods: A Deterministic Framework   总被引:3,自引:3,他引:3  
This paper presents an outline methodology and an operational framework for assessing and mapping the risk of death or serious harm to people from flooding, covering death and physical injuries as a direct and immediate consequence of deep and/or fast flowing floodwaters (usually by drowning), and deaths and physical injuries associated with the flood event (but occurring in the immediate aftermath). The main factors that affect death or injury to people during floods include flow velocity, flow depth, and the degree to which people are exposed to the flood. The exposure potential is related to such factors as the “suddenness” of flooding (and amount of flood warning), the extent of the floodplain, people’s location on the floodplain, and the character of their accommodation. In addition, risks to people are affected by social factors including their vulnerability and behaviour. A methodology is described for estimating the likely annual number of deaths/injuries. This is based on defining zones of different flood hazard and, for each zone, estimating the total number of people located there, the proportion that are likely to be exposed to a flood, and the proportion of those exposed who are likely to be injured or killed during a flood event. The results for each zone are combined to give an overall risk for each flood cell and/or community. The objective of the research reported here is to develop a method which could be applied using a map-based approach in which flood risks to people are calculated and displayed spatially for selected areas or communities. The information needed for each part of the process is described in the paper, and the further research to provide the required information is identified.  相似文献   

15.
Flooding is one of the major natural hazards in Taiwan, and most of the low-lying areas in Taiwan are flood-prone areas. In order to minimize loss of life and economic losses, a detailed and comprehensive decision-making tool is necessary for both flood control planning and emergency service operations. The objectives of this research were (i) to develop a hierarchical structure through the analytic hierarchy process (AHP) to provide preferred options for flood risk analysis, (ii) to map the relative flood risk using the geographic information system (GIS), and (iii) to integrate these two methodologies and apply them to one urban and one semi-rural area in central Taiwan. Fushin Township and the floodplain of Fazih River (1 km on either side of the channel) in Taichung City were selected for this study. In this paper, the flood risk is defined as the relative flood risk due to broken dikes or the failure of stormwater drainage systems. Seven factors were considered in relation to the failure of stormwater drainage, and five to that of broken dikes. Following well-defined procedures, flood maps were drawn based on the data collected from expert responses to a questionnaire, the field survey, satellite images, and documents from flood management agencies. The relative values of flood risk are presented using a 200-m grid for the two study areas. It is concluded that integration of AHP and GIS in flood risk assessment can provide useful detailed information for flood risk management, and the method can be easily applied to most areas in Taiwan where required data sets are readily available.  相似文献   

16.
Coastal flooding has caused significant damage to a number of communities around the Firth of Clyde in south-west Scotland, UK. The Firth of Clyde is an enclosed embayment affected by storm surge generated in the Northern Atlantic and propagated through the Irish Channel. In recent years, the worst flooding occurred on 5th January 1991 with the estimated damage of approximately £7M. On average, some £0.5M damage is caused each year by coastal flooding. With the latest climate change predictions suggesting increased storm activity and the expected increase in mean sea levels, these damages are likely to increase. In line with the expansion of flood warning provision in Scotland, the Scottish Environment Protection Agency (SEPA) has developed a flood warning system to provide local authorities and emergency services with up to 24 h warning of coastal flooding within the Firth of Clyde and River Clyde Estuary up to Glasgow City Centre. The Firth of Clyde flood warning system consists of linked 1-D and 2-D mathematical models of the Firth of Clyde and Clyde Estuary, and other software tools for data processing, viewing and generating warning messages. The general methodology adopted in its implementation was developed following extensive consultation with the relevant authorities, including local councils and police. The warning system was launched in October 1999 and has performed well during four winter flood seasons. The system currently makes forecasts four times a day and is the only operational coastal flood warning system in Scotland.This paper summarises the development of the warning system, gives a review of its operation since its launch in 1999 and discusses future developments in flood warning in Scotland.  相似文献   

17.
This paper deals with the presentation of a flood warning system (GFWS) developed for the specific characteristics of the Guadalhorce basin (3,200 km2, SE of Spain), which is poorly gauged and often affected by flash and plain floods. Its complementarity with the European flood alert system (EFAS) has also been studied. At a lower resolution, EFAS is able to provide a flood forecast several days in advance. The GFWS is adapted to the use of distributed rainfall maps (such as radar rainfall estimates), and discharge forecasts are computed using a distributed rainfall–runoff model. Due to the lack of flow measurements, the model parameters calibrated on a small watershed have been transferred in most of the basin area. The system is oriented to provide distributed warnings and fulfills the requirements of ungauged basins. This work reports on the performance of the system on two recent rainfall events that caused several inundations. These results show how the GFWS performed well and was able to forecast the location and timing of flooding. It demonstrates that despite its limitations, a simple rainfall–runoff model and a relatively simple calibration could be useful for event risk management. Moreover, with low resolution and long anticipation, EFAS appears as a good complement tool to improve flood forecasting and compensate for the short lead times of the GFWS.  相似文献   

18.
This article evaluates some of the factors which limit the human benefits of hazard warnings, with specific reference to flood warnings, and we conclude by suggesting ways of enhancing these benefits. We focus mainly upon the economic benefits generated by flood damage savings by households that warnings facilitate; health effects of flooding and flood warnings; and the effects of warnings on loss of life and physical injury. Our results, based partly upon surveys of flooded households, reveal that economic benefits are currently more limited than we previously thought, but that for several reasons these benefits are likely to be under-estimated. We argue that the intangible benefits to public health, safety and security must also be taken into account in decisions about investment in flood warnings. In England and Wales, the public’s response to flood warnings is currently low and is a key benefit-limiting factor which could begin to undermine a recent major shift in national flood risk management policy towards a more people-centred, portfolio approach in which changing human behaviour is viewed as important. Using a trans-disciplinary approach, we discuss the evidence and literature surrounding this poor response, and suggest a number of ways in which the issue may be addressed in future.  相似文献   

19.
Comparison of TRMM-based flood indices for Gaziantep,Turkey   总被引:1,自引:0,他引:1  
Floods are the most common natural disasters threatening the welfare of humanity. Gaziantep, a city located in a semi-arid region of Turkey, is occasionally flooded, and in May 2014, a flood not only caused property damage, but also resulted in the death of a lady who became trapped in flood waters. The fatality and property damage of flash floods arise from the limited response time for remediation. Despite improvements in numerical weather predictions, forecasting flash floods is not easy. Due to its frequent observations, Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) real-time (RT) 3B42RT data are tested for Gaziantep flood predictions in this study. During TRMM era, six floods occurred in Gaziantep. Three-hourly 3B42RT data covering the 2000- to 2014-year period indicated high rain rates during months in which floods were observed. Also daily variation of rainfall was well represented. High-intensity rain (HIR), cumulative distribution functions (CDF) and Gaziantep Flood Index (GAFI) indices are developed for flood characterization. HIR, calculated as 10 mm/h, detected October and December of 2010 floods. CDFs with 99, 98.5, 95 and 91.3% indicated 4 floods occurred in August 2005, June 2007, October 2010 and December 2010, respectively. GAFI was able to detect 4 out of 6 occurrences (August 2005, June 2007, October 2010 and December 2010) as values ranging from 1 to 2.63 are selected for monthly precipitation. In the missed occurrence, 3B42RT did not indicate any rainfall. Although only rain rates are used in flood characterization, the results are promising, and the simplicity of the methodology favors its usage. Also, methodology can easily be implemented to TRMM following missions such as Global Precipitation Measurement Mission.  相似文献   

20.
Todhunter  P. E. 《Natural Hazards》2021,106(3):2797-2824

Devils Lake, a terminal lake in northeast North Dakota (USA), has experienced catastrophic flooding since 1993. From January 31, 1993, to December 31, 2014, lake level rose from 433.62 to 442.44 m, lake area expanded from 179.9 to 653.5 km2, and lake volume increased from 0.70 to 3.80 km3. More than $1 billion ($USD) has been spent in government payments to mitigate direct, primary, tangible flood damages. This paper provides a case study of the hydrological basis of the Devils Lake flood disaster. The unique geomorphic setting, paleoclimatic record, and hydroclimatic conditions of the region are summarized, and a wide range of hydroclimatic data is examined to provide a broad understanding of the physical basis of the flood disaster. The primary cause of the disaster was a transition to a sustained wetter climate that resulted in a dramatic response in basin hydrological variables in 1993. The transition from a long-term dry period to a long-term wet period caused the lake water budget to begin to change from an atmosphere-controlled water budget dominated by precipitation input to an amplifier lake water budget dominated by surface runoff input to the lake. Other important hydrological factors include a nonlinear precipitation–runoff relationship following the long-term drought, fill-spill and fill-merge hydrological behavior that is characteristic of wetland complexes, an increase in the lake area-to-basin area ratio, and the critical role of frozen soils in controlling infiltration and runoff production of spring snowmelt. Engineering works to manage lake volume through two outlets have reduced, but not entirely eliminated, future flood risk.

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