Optimal control of diarrhea transmission in a flood evacuation zone

Science.gov (United States)

Erwina, N.; Aldila, D.; Soewono, E.

2014-03-01

Evacuation of residents and diarrhea disease outbreak in evacuation zone have become serious problem that frequently happened during flood periods. Limited clean water supply and infrastructure in evacuation zone contribute to a critical spread of diarrhea. Transmission of diarrhea disease can be reduced by controlling clean water supply and treating diarrhea patients properly. These treatments require significant amount of budget, which may not be fulfilled in the fields. In his paper, transmission of diarrhea disease in evacuation zone using SIRS model is presented as control optimum problem with clean water supply and rate of treated patients as input controls. Existence and stability of equilibrium points and sensitivity analysis are investigated analytically for constant input controls. Optimum clean water supply and rate of treatment are found using optimum control technique. Optimal results for transmission of diarrhea and the corresponding controls during the period of observation are simulated numerically. The optimum result shows that transmission of diarrhea disease can be controlled with proper combination of water supply and rate of treatment within allowable budget.

Optimization of wetland restoration siting and zoning in flood retention areas of river basins in China: A case study in Mengwa, Huaihe River Basin

Science.gov (United States)

Zhang, Xiaolei; Song, Yuqin

2014-11-01

Wetland restoration in floodplains is an ecological solution that can address basin-wide flooding issues and minimize flooding and damages to riverine and downstream areas. High population densities, large economic outputs, and heavy reliance on water resources make flood retention and management pressing issues in China. To balance flood control and sustainable development economically, socially, and politically, flood retention areas have been established to increase watershed flood storage capacities and enhance the public welfare for the populace living in the areas. However, conflicts between flood storage functions and human habitation appear irreconcilable. We developed a site-specific methodology for identifying potential sites and functional zones for wetland restoration in a flood retention area in middle and eastern China, optimizing the spatial distribution and functional zones to maximize flood control and human and regional development. This methodology was applied to Mengwa, one of 21 flood retention areas in China's Huaihe River Basin, using nine scenarios that reflected different flood, climatic, and hydraulic conditions. The results demonstrated improved flood retention and ecological functions, as well as increased economic benefits.

Modeling Flood Hazard Zones at the Sub-District Level with the Rational Model Integrated with GIS and Remote Sensing Approaches

Directory of Open Access Journals (Sweden)

Daniel Asare-Kyei

2015-07-01

Full Text Available Robust risk assessment requires accurate flood intensity area mapping to allow for the identification of populations and elements at risk. However, available flood maps in West Africa lack spatial variability while global datasets have resolutions too coarse to be relevant for local scale risk assessment. Consequently, local disaster managers are forced to use traditional methods such as watermarks on buildings and media reports to identify flood hazard areas. In this study, remote sensing and Geographic Information System (GIS techniques were combined with hydrological and statistical models to delineate the spatial limits of flood hazard zones in selected communities in Ghana, Burkina Faso and Benin. The approach involves estimating peak runoff concentrations at different elevations and then applying statistical methods to develop a Flood Hazard Index (FHI. Results show that about half of the study areas fall into high intensity flood zones. Empirical validation using statistical confusion matrix and the principles of Participatory GIS show that flood hazard areas could be mapped at an accuracy ranging from 77% to 81%. This was supported with local expert knowledge which accurately classified 79% of communities deemed to be highly susceptible to flood hazard. The results will assist disaster managers to reduce the risk to flood disasters at the community level where risk outcomes are first materialized.

Investigating the influence of DNAPL spill characteristics on source zone architecture and mass removal in pool-dominated source zones

Science.gov (United States)

Wallace, K. A.; Abriola, L.; Chen, M.; Ramsburg, A.; Pennell, K. D.; Christ, J.

2009-12-01

Multiphase, compositional simulators were employed to investigate the spill characteristics and subsurface properties that lead to pool-dominated, dense non-aqueous phase liquid (DNAPL) source zone architectures. DNAPL pools commonly form at textural interfaces where low permeability lenses restrict the vertical migration of DNAPL, allowing for DNAPL to accumulate, reaching high saturation. Significant pooling has been observed in bench-scale experiments and field settings. However, commonly employed numerical simulations rarely predict the pooling suspected in the field. Given the importance of pooling on the efficacy of mass recovery and the down-gradient contaminant signal, it is important to understand the predominant factors affecting the creation of pool-dominated source zones and their subsequent mass discharge. In this work, contaminant properties, spill characteristics and subsurface permeability were varied to investigate the factors contributing to the development of a pool-dominated source zone. DNAPL infiltration and entrapment simulations were conducted in two- and three-dimensional domains using the University of Texas Chemical Compositional (UTCHEM) simulator. A modified version of MT3DMS was then used to simulate DNAPL dissolution and mass discharge. Numerical mesh size was varied to investigate the importance of numerical model parameters on simulations results. The temporal evolution of commonly employed source zone architecture metrics, such as the maximum DNAPL saturation, first and second spatial moments, and fraction of DNAPL mass located in pools, was monitored to determine how the source zone architecture evolved with time. Mass discharge was monitored to identify the link between source zone architecture and down-gradient contaminant flux. Contaminant characteristics and the presence of extensive low permeability lenses appeared to have the most influence on the development of a pool-dominated source zone. The link between DNAPL mass

Evaluating the purity of a (57)Co flood source by PET.

Science.gov (United States)

DiFilippo, Frank P

2014-11-01

Flood sources of (57)Co are commonly used for quality control of gamma cameras. Flood uniformity may be affected by the contaminants (56)Co and (58)Co, which emit higher energy photons. Although vendors specify a maximum combined (56)Co and (58)Co activity, a convenient test for flood source purity that is feasible in a clinical environment would be desirable. Both (56)Co and (58)Co emit positrons with branching 19.6% and 14.9%, respectively. As is known from (90)Y imaging, a positron emission tomography (PET) scanner is capable of quantitatively imaging very weak positron emission in a high single-photon background. To evaluate this approach, two (57)Co flood sources were scanned with a clinical PET/CT multiple times over a period of months. The (56)Co and (58)Co activity was clearly visible in the reconstructed PET images. Total impurity activity was quantified from the PET images after background subtraction of prompt gamma coincidences. Time-of-flight PET reconstruction was highly beneficial for accurate image quantification. Repeated measurements of the positron-emitting impurities showed excellent agreement with an exponential decay model. For both flood sources studied, the fit parameters indicated a zero intercept and a decay half-life consistent with a mixture of (56)Co and (58)Co. The total impurity activity at the reference date was estimated to be 0.06% and 0.07% for the two sources, which was consistent with the vendor's specification of <0.12%. The robustness of the repeated measurements and a thorough analysis of the detector corrections and physics suggest that the accuracy is acceptable and that the technique is feasible. Further work is needed to validate the accuracy of this technique with a calibrated high resolution gamma spectrometer as a gold standard, which was not available for this study, and for other PET detector models.

Using open source data for flood risk mapping and management in Brazil

Science.gov (United States)

Whitley, Alison; Malloy, James; Chirouze, Manuel

2013-04-01

Whitley, A., Malloy, J. and Chirouze, M. Worldwide the frequency and severity of major natural disasters, particularly flooding, has increased. Concurrently, countries such as Brazil are experiencing rapid socio-economic development with growing and increasingly concentrated populations, particularly in urban areas. Hence, it is unsurprising that Brazil has experienced a number of major floods in the past 30 years such as the January 2011 floods which killed 900 people and resulted in significant economic losses of approximately 1 billion US dollars. Understanding, mitigating against and even preventing flood risk is high priority. There is a demand for flood models in many developing economies worldwide for a range of uses including risk management, emergency planning and provision of insurance solutions. However, developing them can be expensive. With an increasing supply of freely-available, open source data, the costs can be significantly reduced, making the tools required for natural hazard risk assessment more accessible. By presenting a flood model developed for eight urban areas of Brazil as part of a collaboration between JBA Risk Management and Guy Carpenter, we explore the value of open source data and demonstrate its usability in a business context within the insurance industry. We begin by detailing the open source data available and compare its suitability to commercially-available equivalents for datasets including digital terrain models and river gauge records. We present flood simulation outputs in order to demonstrate the impact of the choice of dataset on the results obtained and its use in a business context. Via use of the 2D hydraulic model JFlow+, our examples also show how advanced modelling techniques can be used on relatively crude datasets to obtain robust and good quality results. In combination with accessible, standard specification GPU technology and open source data, use of JFlow+ has enabled us to produce large-scale hazard maps

Analysis of flood inundation in ungauged basins based on multi-source remote sensing data.

Science.gov (United States)

Gao, Wei; Shen, Qiu; Zhou, Yuehua; Li, Xin

2018-02-09

Floods are among the most expensive natural hazards experienced in many places of the world and can result in heavy losses of life and economic damages. The objective of this study is to analyze flood inundation in ungauged basins by performing near-real-time detection with flood extent and depth based on multi-source remote sensing data. Via spatial distribution analysis of flood extent and depth in a time series, the inundation condition and the characteristics of flood disaster can be reflected. The results show that the multi-source remote sensing data can make up the lack of hydrological data in ungauged basins, which is helpful to reconstruct hydrological sequence; the combination of MODIS (moderate-resolution imaging spectroradiometer) surface reflectance productions and the DFO (Dartmouth Flood Observatory) flood database can achieve the macro-dynamic monitoring of the flood inundation in ungauged basins, and then the differential technique of high-resolution optical and microwave images before and after floods can be used to calculate flood extent to reflect spatial changes of inundation; the monitoring algorithm for the flood depth combining RS and GIS is simple and easy and can quickly calculate the depth with a known flood extent that is obtained from remote sensing images in ungauged basins. Relevant results can provide effective help for the disaster relief work performed by government departments.

Source and composition of surface water dissolved organic matter (DOM) and the effect of flood events on the organic matter cycling

Science.gov (United States)

Bondar-Kunze, Elisabeth; Welti, Nina; Tritthart, Michael; Baker, Andrew; Pinay, Gilles; Hein, Thomas

2014-05-01

Floodplains are often simultaneously affected by land use change, river regulation and loss of hydrological dynamics which alter the surface water connectivity between floodplain and river main channel. These alterations can have significant impacts on the sources of organic matter and their degradation and thus, the carbon cycling of riverine landscapes. Although floodplains are known to be important sources of dissolved organic matter (DOM) within watersheds, reduced hydrological connectivity impair their role. The key questions of our research were to determine i) to what extent the degree of connection between the Danube River and its floodplain controlled the DOM composition with its backwater systems, and ii) what were the effects of the DOM changes on carbon cycling in floodplains during two flood events with different magnitude? In this study we report on the variations in DOM spectrophotometric properties of surface waters in different connected floodplain areas and during two flood events of different magnitude in a section of the Alluvial Zone National Park of the Danube River downstream Vienna, Austria. Two backwater floodplain systems were studied, one backwater system mostly disconnected from the fluvial dynamics except during high flood events (Lower Lobau) and the second one, recently restored and connected even during mean flow conditions (Orth). Fluorescence excitation-emission matrix (EEM) spectrophotometry and water chemical analyses were applied to investigate the DOM dynamics. In both backwater systems 15 sites were sampled monthly for two years and every second day during a flood event.

A National Assessment of Changes in Flood Exposure in the United States

Science.gov (United States)

Lam, N.; Qiang, Y.; Cai, H.; Zou, L.

2017-12-01

Analyzing flood exposure and its temporal trend is the first step toward understanding flood risk, flood hazard, and flood vulnerability. This presentation is based on a national, county-based study assessing the changes in population and urban areas in high-risk flood zones from 2001-2011 in the contiguous United States. Satellite land use land cover data, Federal Emergency Management Agency (FEMA)'s 100-year flood maps, and census data were used to extract the proportion of developed (urban) land in flood zones by county in the two time points, and indices of difference were calculated. Local Moran's I statistic was applied to identify hotspots of increase in urban area in flood zones, and geographically weighted regression was used to estimate the population in flood zones from the land cover data. Results show that in 2011, an estimate of about 25.3 million people (8.3% of the total population) lived in the high-risk flood zones. Nationally, the ratio of urban development in flood zones is less than the ratio of land in flood zones, implying that Americans were responsive to flood hazards by avoiding development in flood zones. However, this trend varied from place to place, with coastal counties having less urban development in flood zones than the inland counties. Furthermore, the contrast between coastal and inland counties increased during 2001-2011. Finally, several exceptions from the trend (hotspots) were detected, most notably New York City and Miami where significant increases in urban development in flood zones were found. This assessment provides important baseline information on the spatial patterns of flood exposure and their changes from 2001-2011. The study pinpoints regions that may need further investigations and better policy to reduce the overall flood risks. Methodologically, the study demonstrates that pixelated land cover data can be integrated with other natural and human data to investigate important societal problems. The same

Delineating risk zones and evaluation of shelter centres for flood disaster management along the Pahang River Basin, Malaysia

Directory of Open Access Journals (Sweden)

Anizan Isahak

2018-04-01

Full Text Available Shelter centres are important locations to safeguard people from helpless situations and are an integral part of disaster risk reduction (DRR, particularly for flood DRR. The establishment of shelter centres, and their design based on scientific assessment, is crucial. Yet, they are very much related to the geographic location, socio-economic conditions and the livelihoods of the affected communities. However, many parts of the developing world are still lagging behind in ensuring such scientific design. Considering the flood disaster in 2014 that affected the residents living along the Pahang River Basin, in this study we delineate the communities at risk and evaluate the existing shelter centres to determine how they reduce people’s vulnerability to the risks associated with rural and urban landscapes. We used spatial analysis tools to delineate risk zones and to evaluate existing evacuation systems. A flood disaster risk map was produced to determine which communities are living with risks. Subsequently, the distribution of shelter centres examined whether they are able to support people living at the flood risk zones. These centres were also evaluated using a set of international guidelines for effective disaster shelters. This reveals that the number of shelter centres is not adequate. The designation and designing of shelter centres are not being done scientifically. The maps produced here have a lot of potential to support disaster management decisions, in particular site selection and the prioritisation of centres. The study concludes with a set of guidelines and recommendations for structural and non-structural measures, such as alternative livelihoods and the potential of ecotourism, which may improve the resilience among flood-affected communities; and the decision-making process for the overall flood DRR initiatives.

Modeling multi-source flooding disaster and developing simulation framework in Delta

Science.gov (United States)

Liu, Y.; Cui, X.; Zhang, W.

2016-12-01

Most Delta regions of the world are densely populated and with advanced economies. However, due to impact of the multi-source flooding (upstream flood, rainstorm waterlogging, storm surge flood), the Delta regions is very vulnerable. The academic circles attach great importance to the multi-source flooding disaster in these areas. The Pearl River Delta urban agglomeration in south China is selected as the research area. Based on analysis of natural and environmental characteristics data of the Delta urban agglomeration(remote sensing data, land use data, topographic map, etc.), hydrological monitoring data, research of the uneven distribution and process of regional rainfall, the relationship between the underlying surface and the parameters of runoff, effect of flood storage pattern, we use an automatic or semi-automatic method for dividing spatial units to reflect the runoff characteristics in urban agglomeration, and develop an Multi-model Ensemble System in changing environment, including urban hydrologic model, parallel computational 1D&2D hydrodynamic model, storm surge forecast model and other professional models, the system will have the abilities like real-time setting a variety of boundary conditions, fast and real-time calculation, dynamic presentation of results, powerful statistical analysis function. The model could be optimized and improved by a variety of verification methods. This work was supported by the National Natural Science Foundation of China (41471427); Special Basic Research Key Fund for Central Public Scientific Research Institutes.

Green-blue water in the city: quantification of impact of source control versus end-of-pipe solutions on sewer and river floods.

Science.gov (United States)

De Vleeschauwer, K; Weustenraad, J; Nolf, C; Wolfs, V; De Meulder, B; Shannon, K; Willems, P

2014-01-01

Urbanization and climate change trends put strong pressures on urban water systems. Temporal variations in rainfall, runoff and water availability increase, and need to be compensated for by innovative adaptation strategies. One of these is stormwater retention and infiltration in open and/or green spaces in the city (blue-green water integration). This study evaluated the efficiency of three adaptation strategies for the city of Turnhout in Belgium, namely source control as a result of blue-green water integration, retention basins located downstream of the stormwater sewers, and end-of-pipe solutions based on river flood control reservoirs. The efficiency of these options is quantified by the reduction in sewer and river flood frequencies and volumes, and sewer overflow volumes. This is done by means of long-term simulations (100-year rainfall simulations) using an integrated conceptual sewer-river model calibrated to full hydrodynamic sewer and river models. Results show that combining open, green zones in the city with stormwater retention and infiltration for only 1% of the total city runoff area would lead to a 30 to 50% reduction in sewer flood volumes for return periods in the range 10-100 years. This is due to the additional surface storage and infiltration and consequent reduction in urban runoff. However, the impact of this source control option on downstream river floods is limited. Stormwater retention downstream of the sewer system gives a strong reduction in peak discharges to the receiving river. However due to the difference in response time between the sewer and river systems, this does not lead to a strong reduction in river flood frequency. The paper shows the importance of improving the interface between urban design and water management, and between sewer and river flood management.

Flood Response System—A Case Study

Directory of Open Access Journals (Sweden)

Yogesh Kumar Singh

2017-06-01

Full Text Available Flood Response System (FRS is a network-enabled solution developed using open-source software. The system has query based flood damage assessment modules with outputs in the form of spatial maps and statistical databases. FRS effectively facilitates the management of post-disaster activities caused due to flood, like displaying spatial maps of area affected, inundated roads, etc., and maintains a steady flow of information at all levels with different access rights depending upon the criticality of the information. It is designed to facilitate users in managing information related to flooding during critical flood seasons and analyzing the extent of damage. The inputs to FRS are provided using two components: (1 a semi-automated application developed indigenously, to delineate inundated areas for Near-Real Time Flood Monitoring using Active Microwave Remote Sensing data and (2 a two-dimensional (2D hydrodynamic river model generated outputs for water depth and velocity in flooded areas for an embankment breach scenario. The 2D Hydrodynamic model, CCHE2D (Center for Computational Hydroscience and Engineering Two-Dimensional model, was used to simulate an area of 600 km2 in the flood-prone zone of the Brahmaputra basin. The resultant inundated area from the model was found to be 85% accurate when validated with post-flood optical satellite data.

Uncertainty and Sensitivity of Direct Economic Flood Damages: the FloodRisk Free and Open-Source Software

Science.gov (United States)

Albano, R.; Sole, A.; Mancusi, L.; Cantisani, A.; Perrone, A.

2017-12-01

The considerable increase of flood damages in the the past decades has shifted in Europe the attention from protection against floods to managing flood risks. In this context, the expected damages assessment represents a crucial information within the overall flood risk management process. The present paper proposes an open source software, called FloodRisk, that is able to operatively support stakeholders in the decision making processes with a what-if approach by carrying out the rapid assessment of the flood consequences, in terms of direct economic damage and loss of human lives. The evaluation of the damage scenarios, trough the use of the GIS software proposed here, is essential for cost-benefit or multi-criteria analysis of risk mitigation alternatives. However, considering that quantitative assessment of flood damages scenarios is characterized by intrinsic uncertainty, a scheme has been developed to identify and quantify the role of the input parameters in the total uncertainty of flood loss model application in urban areas with mild terrain and complex topography. By the concept of parallel models, the contribution of different module and input parameters to the total uncertainty is quantified. The results of the present case study have exhibited a high epistemic uncertainty on the damage estimation module and, in particular, on the type and form of the utilized damage functions, which have been adapted and transferred from different geographic and socio-economic contexts because there aren't depth-damage functions that are specifically developed for Italy. Considering that uncertainty and sensitivity depend considerably on local characteristics, the epistemic uncertainty associated with the risk estimate is reduced by introducing additional information into the risk analysis. In the light of the obtained results, it is evident the need to produce and disseminate (open) data to develop micro-scale vulnerability curves. Moreover, the urgent need to push

A new look at the Flood Pulse Concept : The (ir)relevance of the moving littoral in temperate zone rivers

NARCIS (Netherlands)

Keizer, F. M.|info:eu-repo/dai/nl/411259784; Schot, P. P.|info:eu-repo/dai/nl/08071563X; Okruszko, T.; Chormański, J.; Kardel, I.; Wassen, M. J.|info:eu-repo/dai/nl/07165710X

2014-01-01

The Flood Pulse Concept links the hydraulic river flood pulse to floodplain nutrient status. The edge of inundation, referred to as the moving littoral, causes wetting and drying and input of river derived nutrients, resulting in high floodplain productivity. If during the floods other water sources

Open Source Web-Based Solutions for Disseminating and Analyzing Flood Hazard Information at the Community Level

Science.gov (United States)

Santillan, M. M.-M.; Santillan, J. R.; Morales, E. M. O.

2017-09-01

We discuss in this paper the development, including the features and functionalities, of an open source web-based flood hazard information dissemination and analytical system called "Flood EViDEns". Flood EViDEns is short for "Flood Event Visualization and Damage Estimations", an application that was developed by the Caraga State University to address the needs of local disaster managers in the Caraga Region in Mindanao, Philippines in accessing timely and relevant flood hazard information before, during and after the occurrence of flood disasters at the community (i.e., barangay and household) level. The web application made use of various free/open source web mapping and visualization technologies (GeoServer, GeoDjango, OpenLayers, Bootstrap), various geospatial datasets including LiDAR-derived elevation and information products, hydro-meteorological data, and flood simulation models to visualize various scenarios of flooding and its associated damages to infrastructures. The Flood EViDEns application facilitates the release and utilization of this flood-related information through a user-friendly front end interface consisting of web map and tables. A public version of the application can be accessed at http://121.97.192.11:8082/. The application is currently expanded to cover additional sites in Mindanao, Philippines through the "Geo-informatics for the Systematic Assessment of Flood Effects and Risks for a Resilient Mindanao" or the "Geo-SAFER Mindanao" Program.

Coastal Flood Hazard Composite Layer for the Coastal Flood Exposure Mapper

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is a map service for the Coastal Flood Hazard Composite dataset. This dataset was created by combining hazard zones from the following datasets: FEMA V zones,...

Risk-based zoning for urbanizing floodplains.

Science.gov (United States)

Porse, Erik

2014-01-01

Urban floodplain development brings economic benefits and enhanced flood risks. Rapidly growing cities must often balance the economic benefits and increased risks of floodplain settlement. Planning can provide multiple flood mitigation and environmental benefits by combining traditional structural measures such as levees, increasingly popular landscape and design features (green infrastructure), and non-structural measures such as zoning. Flexibility in both structural and non-structural options, including zoning procedures, can reduce flood risks. This paper presents a linear programming formulation to assess cost-effective urban floodplain development decisions that consider benefits and costs of development along with expected flood damages. It uses a probabilistic approach to identify combinations of land-use allocations (residential and commercial development, flood channels, distributed runoff management) and zoning regulations (development zones in channel) to maximize benefits. The model is applied to a floodplain planning analysis for an urbanizing region in the Baja Sur peninsula of Mexico. The analysis demonstrates how (1) economic benefits drive floodplain development, (2) flexible zoning can improve economic returns, and (3) cities can use landscapes, enhanced by technology and design, to manage floods. The framework can incorporate additional green infrastructure benefits, and bridges typical disciplinary gaps for planning and engineering.

Source zone remediation by zero valent iron technologies

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann

at a fifth of these contaminated sites. These source zones pose a serious threat to soil and groundwater quality. Remediation of the heterogeneous source zones is challenging due to irregular downwards migration patterns in the subsurface, low aqueous solubility and matrix diffusion. To protect the soil...... and groundwater resources from long-term deterioration, the development of in situ technologies suitable for remediation of DNAPL is warranted. Currently, an array of aggressive in situ remediation technologies remediation exists. These technologies may be suitable under various site specific conditions; however......, most of them are limited by subsurface heterogeneities and/or the risk of inadvertent DNAPL displacement during field application. This thesis presents the results of an investigation of the potential for remediation of chlorinated solvent source zones by emerging zero valent iron (ZVI) based...

Delineation of seismic source zones based on seismicity parameters ...

Indian Academy of Sciences (India)

In the present study, an attempt has been made to delineate seismic source zones in the study area (south India) based on the seismicity parameters. Seismicity parameters and the maximum probable earthquake for these source zones were evaluated and were used in the hazard evaluation. The probabilistic evaluation of ...

Groundwater flow, nutrient, and stable isotope dynamics in the parafluvial-hyporheic zone of the regulated Lower Colorado River (Texas, USA) over the course of a small flood

Science.gov (United States)

Briody, Alyse C.; Cardenas, M. Bayani; Shuai, Pin; Knappett, Peter S. K.; Bennett, Philip C.

2016-06-01

Periodic releases from an upstream dam cause rapid stage fluctuations in the Lower Colorado River near Austin, Texas, USA. These daily pulses modulate fluid exchange and residence times in the hyporheic zone where biogeochemical reactions are typically pronounced. The effects of a small flood pulse under low-flow conditions on surface-water/groundwater exchange and biogeochemical processes were studied by monitoring and sampling from two dense transects of wells perpendicular to the river. The first transect recorded water levels and the second transect was used for water sample collection at three depths. Samples were collected from 12 wells every 2 h over a 24-h period which had a 16-cm flood pulse. Analyses included nutrients, carbon, major ions, and stable isotopes of water. The relatively small flood pulse did not cause significant mixing in the parafluvial zone. Under these conditions, the river and groundwater were decoupled, showed potentially minimal mixing at the interface, and did not exhibit any discernible denitrification of river-borne nitrate. The chemical patterns observed in the parafluvial zone can be explained by evaporation of groundwater with little mixing with river water. Thus, large pulses may be necessary in order for substantial hyporheic mixing and exchange to occur. The large regulated river under a low-flow and small flood pulse regime functioned mainly as a gaining river with little hydrologic connectivity beyond a narrow hyporheic zone.

Sex-specific responses to winter flooding, spring waterlogging and post-flooding recovery in Populus deltoides

OpenAIRE

Ling-Feng Miao; Fan Yang; Chun-Yu Han; Yu-Jin Pu; Yang Ding; Li-Jia Zhang

2017-01-01

Winter flooding events are common in some rivers and streams due to dam constructions, and flooding and waterlogging inhibit the growth of trees in riparian zones. This study investigated sex-specific morphological, physiological and ultrastructural responses to various durations of winter flooding and spring waterlogging stresses, and post-flooding recovery characteristics in Populus deltoides. There were no significant differences in the morphological, ultrastructural and the majority of ph...

The impact of bathymetry input on flood simulations

Science.gov (United States)

Khanam, M.; Cohen, S.

2017-12-01

Flood prediction and mitigation systems are inevitable for improving public safety and community resilience all over the worldwide. Hydraulic simulations of flood events are becoming an increasingly efficient tool for studying and predicting flood events and susceptibility. A consistent limitation of hydraulic simulations of riverine dynamics is the lack of information about river bathymetry as most terrain data record water surface elevation. The impact of this limitation on the accuracy on hydraulic simulations of flood has not been well studies over a large range of flood magnitude and modeling frameworks. Advancing our understanding of this topic is timely given emerging national and global efforts for developing automated flood predictions systems (e.g. NOAA National Water Center). Here we study the response of flood simulation to the incorporation of different bathymetry and floodplain surveillance source. Different hydraulic models are compared, Mike-Flood, a 2D hydrodynamic model, and GSSHA, a hydrology/hydraulics model. We test a hypothesis that the impact of inclusion/exclusion of bathymetry data on hydraulic model results will vary in its magnitude as a function of river size. This will allow researcher and stake holders more accurate predictions of flood events providing useful information that will help local communities in a vulnerable flood zone to mitigate flood hazards. Also, it will help to evaluate the accuracy and efficiency of different modeling frameworks and gage their dependency on detailed bathymetry input data.

Spatial Analytic Hierarchy Process Model for Flood Forecasting: An Integrated Approach

International Nuclear Information System (INIS)

Matori, Abd Nasir; Yusof, Khamaruzaman Wan; Hashim, Mustafa Ahmad; Lawal, Dano Umar; Balogun, Abdul-Lateef

2014-01-01

Various flood influencing factors such as rainfall, geology, slope gradient, land use, soil type, drainage density, temperature etc. are generally considered for flood hazard assessment. However, lack of appropriate handling/integration of data from different sources is a challenge that can make any spatial forecasting difficult and inaccurate. Availability of accurate flood maps and thorough understanding of the subsurface conditions can adequately enhance flood disasters management. This study presents an approach that attempts to provide a solution to this drawback by combining Geographic Information System (GIS)-based Analytic Hierarchy Process (AHP) model as spatial forecasting tools. In achieving the set objectives, spatial forecasting of flood susceptible zones in the study area was made. A total number of five set of criteria/factors believed to be influencing flood generation in the study area were selected. Priority weights were assigned to each criterion/factor based on Saaty's nine point scale of preference and weights were further normalized through the AHP. The model was integrated into a GIS system in order to produce a flood forecasting map

HIGH RISK ZONES ON FLOODS AND LANDSLIDES DISASTERS IN RWANDA

Directory of Open Access Journals (Sweden)

Nsengiyumva J.ean Baptiste

2014-01-01

Full Text Available Disaster risk management as an issue at stake worldwide shifts its emphases from post disaster to pre-disaster phases. Management activities required in pre-disaster phases, such as risk assessment, hazard identification, preparedness or preventive and mitigation measures needs detailed information about hazard characteristics, social, economic, structural vulnerability and capacity. That information is not usually available in many different countries, as it is the case in Rwanda. Based on the international experiences and practices, knowledge of disaster prone areas can be assumed as an alternative for detailed information acquisition, thus contributing to effective disaster risk management. Identification of disaster higher risk zones on floods and landslides, can lead to better understanding of disaster risk and putting in place measures for risk reduction. Consequently, as Rwanda is prone to natural hazards with lack of adequate information that is essential for effective disaster risk management, due to limited scientific researches; this study aims to address that gap. The results revealed that some areas of the North-Western parts of Rwanda are highly prone to floods and landslides, namely Burera, Musanze, Rulindo, Nyabihu, Ngororero and Rubavu Districts. This is aggravated by some triggering factors such as steep slopes, soil types, heavy rains, landuse Practices and others. Intensity and frequency of disaster events vary from district to district and this geographical dispersal confirms the non-spatial clustering (as confirmed by Moran’s I analysis of risks due to uneven level of Disaster vulnerabilities, coping capacities and available hazards whereby lack of normal distribution of hazards all over all Districts.

Ionization dual-zone static detector having single radioactive source

International Nuclear Information System (INIS)

Ried, L. Jr.; Wade, A.L.

1977-01-01

This ionization detector or combustion product detector includes a single radioactive source located in an ionization chamber, and the ionization chamber includes portions comprising a reference zone and a signal zone. Electrical circuitry connected to the reference and signal zones provides an output signal directly related to changes in voltages across the signal zone in relation to the amount of particulates of combustion present in the ionization chamber

Quantifying riverine and storm-surge flood risk by single-family residence: application to Texas.

Science.gov (United States)

Czajkowski, Jeffrey; Kunreuther, Howard; Michel-Kerjan, Erwann

2013-12-01

The development of catastrophe models in recent years allows for assessment of the flood hazard much more effectively than when the federally run National Flood Insurance Program (NFIP) was created in 1968. We propose and then demonstrate a methodological approach to determine pure premiums based on the entire distribution of possible flood events. We apply hazard, exposure, and vulnerability analyses to a sample of 300,000 single-family residences in two counties in Texas (Travis and Galveston) using state-of-the-art flood catastrophe models. Even in zones of similar flood risk classification by FEMA there is substantial variation in exposure between coastal and inland flood risk. For instance, homes in the designated moderate-risk X500/B zones in Galveston are exposed to a flood risk on average 2.5 times greater than residences in X500/B zones in Travis. The results also show very similar average annual loss (corrected for exposure) for a number of residences despite their being in different FEMA flood zones. We also find significant storm-surge exposure outside of the FEMA designated storm-surge risk zones. Taken together these findings highlight the importance of a microanalysis of flood exposure. The process of aggregating risk at a flood zone level-as currently undertaken by FEMA-provides a false sense of uniformity. As our analysis indicates, the technology to delineate the flood risks exists today. © 2013 Society for Risk Analysis.

Sero-epidemiology and hemato-biochemical study of bovine leptospirosis in flood affected zone of Pakistan.

Science.gov (United States)

Ijaz, Muhammad; Abbas, Syed Nazar; Farooqi, Shahid Hussain; Aqib, Amjad Islam; Anwar, Ghulam Ali; Rehman, Abdul; Ali, Muhammad Muddassir; Mehmood, Khalid; Khan, Amjad

2018-01-01

The bovine leptospirosis is an economically important zoonotic disease of flood affected areas worldwide, but scarce information is available about its epidemiology in Pakistan. This is a first study on sero-epidemiology of bovine leptospirosis in Pakistan. The objectives of this study were to investigate the sero-prevalence and associated risk factors of bovine leptospirosis in flood affected zone of Punjab, Pakistan. A total of 385 serum samples were randomly collected from four tehsils of district Muzaffargarh, Pakistan. The serum samples were subjected to indirect ELISA for the detection of anti-leptospira antibodies. The overall sero-prevalence of leptospirosis was 30.39%. The prevalence was significantly higher (p0.05) difference among TLC values among sero-positive and sero-negative animals. The serum biochemical profile revealed significant differences (pPakistan, and the disease needs to be explored comprehensively in other parts of the country to sort out solid strategies for its control and eradication. Copyright © 2017 Elsevier B.V. All rights reserved.

Understanding the geomorphology of macrochannel systems for flood risk management in Queensland, Australia

Science.gov (United States)

Thompson, Chris; Croke, Jacky

2016-04-01

The year 2010-2011 was the wettest on record for the state of Queensland, Australia producing catastrophic floods. A tropical low pressure system in 2013 delivered further extreme flood events across South East Queensland (SEQ) which prompted state and local governments to conduct studies into flood magnitude and frequency in the region and catchment factors contributing to flood hazards. The floods in the region are strongly influenced by El Nino-Southern Oscillation (ENSO) phenomenon, but also modulated by the Interdecadal Pacific Oscillation (IPO) which leads to flood and drought dominated regimes and high hydrological variability. One geomorphic feature in particular exerted a significant control on the transmission speed, the magnitude of flood inundation and resultant landscape resilience. This feature was referred to as a 'macrochannel', a term used to describe a 'large-channel' which has bankfull recurrence intervals generally greater than 10 years. The macrochannels display non-linear downstream hydraulic geometry which leads to zones of flood expansion (when hydraulic geometry decreases) and zones of flood contraction (when hydraulic geometry increases). The pattern of contraction and expansion zones determines flood hazard zones. The floods caused significant wet flow bank mass failures that mobilised over 1,000,000 m3 of sediment in one subcatchment. Results suggest that the wetflow bank mass failures are a stage in a cyclical evolution process which maintains the macrochannel morphology, hence channel resilience to floods. Chronological investigations further show the macrochannels are laterally stable and identify periods of heightened flood activity over the past millennium and upper limits on flood magnitude. This paper elaborates on the results of the geomorphic investigations on Lockyer Creek in SEQ and how the results have alerted managers and policy makers to the different flood responses of these systems and how flood risk management plans can

Evaluation of Flooding Risk and Engineering Protection Against Floods for Ulan-Ude

Science.gov (United States)

Borisova, T. A.

2017-11-01

The report presents the results of the study on analysis and risk assessment in relation to floods for Ulan-Ude and provides the developed recommendations of the activities for engineering protection of the population and economic installations. The current situation is reviewed and the results of the site survey are shown to identify the challenges and areas of negative water influence along with the existing security system. The report presents a summary of floods and index risk assessment. The articles describes the scope of eventual flooding, underflooding and enumerates the economic installations inside the urban areas’ research-based zones of flooding at the rated levels of water to identify the likeliness of exceedance. The assessment of damage from flood equal to 1% is shown.

Use of documentary sources on past flood events for flood risk management and land planning

Science.gov (United States)

Cœur, Denis; Lang, Michel

2008-09-01

The knowledge of past catastrophic events can improve flood risk mitigation policy, with a better awareness against risk. As such historical information is usually available in Europe for the past five centuries, historians are able to understand how past society dealt with flood risk, and hydrologists can include information on past floods into an adapted probabilistic framework. In France, Flood Risk Mitigation Maps are based either on the largest historical known flood event or on the 100-year flood event if it is greater. Two actions can be suggested in terms of promoting the use of historical information for flood risk management: (1) the development of a regional flood data base, with both historical and current data, in order to get a good feedback on recent events and to improve the flood risk education and awareness; (2) the commitment to keep a persistent/perennial management of a reference network of hydrometeorological observations for climate change studies.

Flood Risk Mapping Using Flow Energy Equation and Geographic Information System

Directory of Open Access Journals (Sweden)

pourya Javan

2013-09-01

Full Text Available Flooding and its damages are not only found uplift water level in a region. In other words, the depth and speed parameters together have determining the level of flood risk at each point. This subject is visible in flooded plain with low height and high speed of 2 meters per second, which damages are extensive. According to the criteria of having both velocity and flow depth in the governing equation to the flows energy, this equation seems appropriate to analysis in this study. Various methods have been proposed for increase accuracy in flood zoning with different return periods and risks associated with it in land border of river. For example, some of these methods are considered factors such as analysis of past flooding in the area affected by floods, hydrological factors and consideration of hydraulic elements affecting in flood zoning (such as flow velocity. This paper investigates the effect of flood zoning by the energy flow in the areas affected by floods. Also risk due to flood based on energy flow in each section of the river is compared by the proposed graphs of hazard interval and other done flood zoning in this field. In this study, the FORDO river has been selected as the case study. This river is part of the rivers located in the city of QOM KAHAK. The characteristics of river in upstream and downstream are mountain, young and stable and adult, respectively. Also this river in different seasons is exposed the flood damage. The proposed method in this study can be improving recognition accuracy of flood risk in areas affected by flood. Also, this method facilitate the identify parts of the river bed, that is affected by severe flooding, for decision making to improve rivers organizing.

Groundwater composition fluctuation within technogenic zones (case study: flooded coal mines in Primorsky Krai, Russia)

Science.gov (United States)

Tarasenko, I. A.; Zinkov, A. V.; Vakh, E. A.; Vetoshkina, A. V.; Strelnikova, A. B.

2016-03-01

The paper considers groundwater composition fluctuation within technogenic zones based on evidence from the flooded coal mines of Primorye. The authors have determined the regularities of hydrogeochemical processes, specified the groundwater composition fluctuation within the technogenic complexes located in the liquidated mine areas, and identified the equilibrium phases between the studied waters and specific secondary minerals. It has been proved that water within natural-technogenic complexes in the liquidated mine areas are saturated with silicates, carbonates, sulfates, oxides, and hydroxides, which should be taken into account when designing technologies for groundwater treatment.

Delineation of seismic source zones based on seismicity parameters ...

Indian Academy of Sciences (India)

these source zones were evaluated and were used in the hazard evaluation. ... seismic sources, linear and areal, were considered in the present study to model the seismic sources in the ..... taken as an authentic reference manual for iden-.

Use of historical sources in a study of the 1895 floods on the Danube River and its tributaries

Directory of Open Access Journals (Sweden)

Melo Marián

2014-01-01

Full Text Available Hydrological data series that are measured on the Danube River are temporally limited. Instrumental flow data can be prolonged by documentary data from historical sources in archives. This paper deals with knowledge gained by studies of historical materials regarding the 1895 catastrophic floods on the Danube River and its tributaries as reflected in the contemporary local press and also in studies of other historical records (flood marks, chronicles, books and photos. Records from the newspapers (Wiener Zeitung, Preßburger Zeitung, The New York Times and Komáromi Lapok and other analysed sources show the relatively large territorial impact of the floods in March and April 1895, which affected not only the Danube and its tributaries, but also some neighboring basins. Catastrophic consequences of the flood were especially reported from the lower parts of the Danube River (from its confluence with the Drava River up to the mouth of the Black Sea and the tributaries of the Tisza and Sava rivers. In 1895, the second highest flood after the 2006 flood on the Lower Danube was observed since 1841.

An assessment of flood vulnerability on physical development along ...

African Journals Online (AJOL)

Mohammad

Key words: Drainage channel, flood, risk assessment, vulnerability. INTRODUCTION ... hydraulic and other control structures.” The effects of floods are always ..... An application of Geographic Information System in mapping flood risk zones in ...

Persulfate injection into a gasoline source zone

Science.gov (United States)

Sra, Kanwartej S.; Thomson, Neil R.; Barker, Jim F.

2013-07-01

One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O82 -, SO42 -, Na+, dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for > 10 months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in M indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M increased by > 100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone.

A European Flood Database: facilitating comprehensive flood research beyond administrative boundaries

Directory of Open Access Journals (Sweden)

J. Hall

2015-06-01

Full Text Available The current work addresses one of the key building blocks towards an improved understanding of flood processes and associated changes in flood characteristics and regimes in Europe: the development of a comprehensive, extensive European flood database. The presented work results from ongoing cross-border research collaborations initiated with data collection and joint interpretation in mind. A detailed account of the current state, characteristics and spatial and temporal coverage of the European Flood Database, is presented. At this stage, the hydrological data collection is still growing and consists at this time of annual maximum and daily mean discharge series, from over 7000 hydrometric stations of various data series lengths. Moreover, the database currently comprises data from over 50 different data sources. The time series have been obtained from different national and regional data sources in a collaborative effort of a joint European flood research agreement based on the exchange of data, models and expertise, and from existing international data collections and open source websites. These ongoing efforts are contributing to advancing the understanding of regional flood processes beyond individual country boundaries and to a more coherent flood research in Europe.

Itzï (version 17.1): an open-source, distributed GIS model for dynamic flood simulation

Science.gov (United States)

Guillaume Courty, Laurent; Pedrozo-Acuña, Adrián; Bates, Paul David

2017-05-01

Worldwide, floods are acknowledged as one of the most destructive hazards. In human-dominated environments, their negative impacts are ascribed not only to the increase in frequency and intensity of floods but also to a strong feedback between the hydrological cycle and anthropogenic development. In order to advance a more comprehensive understanding of this complex interaction, this paper presents the development of a new open-source tool named Itzï that enables the 2-D numerical modelling of rainfall-runoff processes and surface flows integrated with the open-source geographic information system (GIS) software known as GRASS. Therefore, it takes advantage of the ability given by GIS environments to handle datasets with variations in both temporal and spatial resolutions. Furthermore, the presented numerical tool can handle datasets from different sources with varied spatial resolutions, facilitating the preparation and management of input and forcing data. This ability reduces the preprocessing time usually required by other models. Itzï uses a simplified form of the shallow water equations, the damped partial inertia equation, for the resolution of surface flows, and the Green-Ampt model for the infiltration. The source code is now publicly available online, along with complete documentation. The numerical model is verified against three different tests cases: firstly, a comparison with an analytic solution of the shallow water equations is introduced; secondly, a hypothetical flooding event in an urban area is implemented, where results are compared to those from an established model using a similar approach; and lastly, the reproduction of a real inundation event that occurred in the city of Kingston upon Hull, UK, in June 2007, is presented. The numerical approach proved its ability at reproducing the analytic and synthetic test cases. Moreover, simulation results of the real flood event showed its suitability at identifying areas affected by flooding

Flood action plans

International Nuclear Information System (INIS)

Slopek, R.J.

1995-01-01

Safe operating procedures developed by TransAlta Utilities for dealing with flooding, resulting from upstream dam failures or extreme rainfalls, were presented. Several operating curves developed by Monenco AGRA were described, among them the No Overtopping Curve (NOC), the Safe Filling Curve (SFC), the No Spill Curve (NSC) and the Guaranteed Fill Curve (GFC). The concept of an operational comfort zone was developed and defined. A flood action plan for all operating staff was created as a guide in case of a flooding incident. Staging of a flood action plan workshop was described. Dam break scenarios pertinent to the Bow River were developed for subsequent incorporation into a Flood Action Plan Manual. Evaluation of the technical presentations made during workshops were found them to have been effective in providing operating staff with a better understanding of the procedures that they would perform in an emergency. 8 figs

Development of Probabilistic Flood Inundation Mapping For Flooding Induced by Dam Failure

Science.gov (United States)

Tsai, C.; Yeh, J. J. J.

2017-12-01

A primary function of flood inundation mapping is to forecast flood hazards and assess potential losses. However, uncertainties limit the reliability of inundation hazard assessments. Major sources of uncertainty should be taken into consideration by an optimal flood management strategy. This study focuses on the 20km reach downstream of the Shihmen Reservoir in Taiwan. A dam failure induced flood herein provides the upstream boundary conditions of flood routing. The two major sources of uncertainty that are considered in the hydraulic model and the flood inundation mapping herein are uncertainties in the dam break model and uncertainty of the roughness coefficient. The perturbance moment method is applied to a dam break model and the hydro system model to develop probabilistic flood inundation mapping. Various numbers of uncertain variables can be considered in these models and the variability of outputs can be quantified. The probabilistic flood inundation mapping for dam break induced floods can be developed with consideration of the variability of output using a commonly used HEC-RAS model. Different probabilistic flood inundation mappings are discussed and compared. Probabilistic flood inundation mappings are hoped to provide new physical insights in support of the evaluation of concerning reservoir flooded areas.

Analysis of core-concrete interaction event with flooding for the Advanced Neutron Source reactor

International Nuclear Information System (INIS)

Kim, S.H.; Taleyarkhan, R.P.; Georgevich, V.; Navarro-Valenti, S.

1993-01-01

This paper discusses salient aspects of the methodology, assumptions, and modeling of various features related to estimation of source terms from an accident involving a molten core-concrete interaction event (with and without flooding) in the Advanced Neutron Source (ANS) reactor at the Oak Ridge National Laboratory. Various containment configurations are considered for this postulated severe accident. Several design features (such as rupture disks) are examined to study containment response during this severe accident. Also, thermal-hydraulic response of the containment and radionuclide transport and retention in the containment are studied. The results are described as transient variations of source terms, which are then used for studying off-site radiological consequences and health effects for the support of the Conceptual Safety Analysis Report for ANS. The results are also to be used to examine the effectiveness of subpile room flooding during this type of severe accident

Study of flood defense structural measures priorities using Compromise Programming technique

Science.gov (United States)

Lim, D.; Jeong, S.

2017-12-01

Recent climate change of global warming has led to the frequent occurrence of heavy regional rainfalls. As such, inundation vulnerability increases in urban areas with high population density due to the low runoff carrying capacity. This study selects a sample area (Janghang-eup, the Republic of Korea), which is one of the most vulnerable areas to flooding, analyzing the urban flood runoff model (XP-SWMM) and using the MCDM (Multi-Criteria Decision Making) technique to establish flood protection structural measures. To this end, we compare the alternatives and choose the optimal flood defense measure: our model is utilized with three flood prevention structural measures; (i) drainage pipe construction; (ii) water detention; and (iii) flood pumping station. Dividing the target area into three small basins, we propose flood evaluations for an inundation decrease by studying the flooded area, the maximum inundation depth, the damaged residential area, and the construction cost. In addition, Compromise Programming determines the priority of the alternatives. As a consequent, this study suggests flood pumping station for Zone 1 and drainage pipe construction for Zone 2 and Zone 3, respectively, as the optimal flood defense alternative. Keywords : MCDM; Compromise Programming; Urban Flood Prevention; This research was supported by a grant [MPSS-DP-2013-62] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

Development of a lead x-ray compensation method in simultaneous Tl-201 SPECT ampersand Tc-99m TCT using a flood source

International Nuclear Information System (INIS)

Motomura, N.; Ichihara, T.; Hasegawa, H.

1996-01-01

Several studies have been reported about simultaneous single photon emission computed tomography (SPECT) and transmission computed tomography (TCT) to obtain the attenuation map needed for non-uniform attenuation compensation methods. To perform SPECT/TCT scans, there are some TCT source and collimator configurations. In the TCT system utilizing a flood source and parallel beam collimator, the advantages are a large field-of-view without truncation, no lateral motion of the source as in the case for the scanning line method, and no fixed source position for the method with a convergent collimator. However the disadvantages of the flood source method are significant scatter component, and blockage of the detector with the flood source attached in multiple-head SPECT systems

Persulfate injection into a gasoline source zone.

Science.gov (United States)

Sra, Kanwartej S; Thomson, Neil R; Barker, Jim F

2013-07-01

One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O8(2-), SO4(2-), Na(+), dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for >10months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in [Formula: see text] indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M˙DIC increased by >100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone. Copyright © 2013 Elsevier B.V. All rights reserved.

DAFNE: A Matlab toolbox for Bayesian multi-source remote sensing and ancillary data fusion, with application to flood mapping

Science.gov (United States)

D'Addabbo, Annarita; Refice, Alberto; Lovergine, Francesco P.; Pasquariello, Guido

2018-03-01

High-resolution, remotely sensed images of the Earth surface have been proven to be of help in producing detailed flood maps, thanks to their synoptic overview of the flooded area and frequent revisits. However, flood scenarios can be complex situations, requiring the integration of different data in order to provide accurate and robust flood information. Several processing approaches have been recently proposed to efficiently combine and integrate heterogeneous information sources. In this paper, we introduce DAFNE, a Matlab®-based, open source toolbox, conceived to produce flood maps from remotely sensed and other ancillary information, through a data fusion approach. DAFNE is based on Bayesian Networks, and is composed of several independent modules, each one performing a different task. Multi-temporal and multi-sensor data can be easily handled, with the possibility of following the evolution of an event through multi-temporal output flood maps. Each DAFNE module can be easily modified or upgraded to meet different user needs. The DAFNE suite is presented together with an example of its application.

Spatial variability and potential impacts of climate change on flood and debris flow hazard zone mapping and implications for risk management

Directory of Open Access Journals (Sweden)

H. Staffler

2008-06-01

Full Text Available The main goals of this study were to identify the alpine torrent catchments that are sensitive to climatic changes and to assess the robustness of the methods for the elaboration of flood and debris flow hazard zone maps to specific effects of climate changes. In this study, a procedure for the identification and localization of torrent catchments in which the climate scenarios will modify the hazard situation was developed. In two case studies, the impacts of a potential increase of precipitation intensities to the delimited hazard zones were studied.

The identification and localization of the torrent and river catchments, where unfavourable changes in the hazard situation occur, could eliminate speculative and unnecessary measures against the impacts of climate changes like a general enlargement of hazard zones or a general over dimensioning of protection structures for the whole territory. The results showed a high spatial variability of the sensitivity of catchments to climate changes. In sensitive catchments, the sediment management in alpine torrents will meet future challenges due to a higher rate for sediment removal from retention basins. The case studies showed a remarkable increase of the areas affected by floods and debris flow when considering possible future precipitation intensities in hazard mapping. But, the calculated increase in extent of future hazard zones lay within the uncertainty of the methods used today for the delimitation of the hazard zones. Thus, the consideration of the uncertainties laying in the methods for the elaboration of hazard zone maps in the torrent and river catchments sensitive to climate changes would provide a useful instrument for the consideration of potential future climate conditions. The study demonstrated that weak points in protection structures in future will become more important in risk management activities.

Application of RUNTA code in flood analyses

International Nuclear Information System (INIS)

Perez Martin, F.; Benitez Fonzalez, F.

1994-01-01

Flood probability analyses carried out to date indicate the need to evaluate a large number of flood scenarios. This necessity is due to a variety of reasons, the most important of which include: - Large number of potential flood sources - Wide variety of characteristics of flood sources - Large possibility of flood-affected areas becoming inter linked, depending on the location of the potential flood sources - Diversity of flood flows from one flood source, depending on the size of the rupture and mode of operation - Isolation times applicable - Uncertainties in respect of the structural resistance of doors, penetration seals and floors - Applicable degrees of obstruction of floor drainage system Consequently, a tool which carries out the large number of calculations usually required in flood analyses, with speed and flexibility, is considered necessary. The RUNTA Code enables the range of possible scenarios to be calculated numerically, in accordance with all those parameters which, as a result of previous flood analyses, it is necessary to take into account in order to cover all the possible floods associated with each flood area

Modeling Degradation Product Partitioning in Chlorinated-DNAPL Source Zones

Science.gov (United States)

Boroumand, A.; Ramsburg, A.; Christ, J.; Abriola, L.

2009-12-01

Metabolic reductive dechlorination degrades aqueous phase contaminant concentrations, increasing the driving force for DNAPL dissolution. Results from laboratory and field investigations suggest that accumulation of cis-dichloroethene (cis-DCE) and vinyl chloride (VC) may occur within DNAPL source zones. The lack of (or slow) degradation of cis-DCE and VC within bioactive DNAPL source zones may result in these dechlorination products becoming distributed among the solid, aqueous, and organic phases. Partitioning of cis-DCE and VC into the organic phase may reduce aqueous phase concentrations of these contaminants and result in the enrichment of these dechlorination products within the non-aqueous phase. Enrichment of degradation products within DNAPL may reduce some of the advantages associated with the application of bioremediation in DNAPL source zones. Thus, it is important to quantify how partitioning (between the aqueous and organic phases) influences the transport of cis-DCE and VC within bioactive DNAPL source zones. In this work, abiotic two-phase (PCE-water) one-dimensional column experiments are modeled using analytical and numerical methods to examine the rate of partitioning and the capacity of PCE-DNAPL to reversibly sequester cis-DCE. These models consider aqueous-phase, nonaqueous phase, and aqueous plus nonaqueous phase mass transfer resistance using linear driving force and spherical diffusion expressions. Model parameters are examined and compared for different experimental conditions to evaluate the mechanisms controlling partitioning. Biot number, a dimensionless number which is an index of the ratio of the aqueous phase mass transfer rate in boundary layer to the mass transfer rate within the NAPL, is used to characterize conditions in which either or both processes are controlling. Results show that application of a single aqueous resistance is capable to capture breakthrough curves when DNAPL is distributed in porous media as low

Integrated Characterization of DNAPL Source Zone Architecture in Clay Till and Limestone Bedrock

DEFF Research Database (Denmark)

Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann

2014-01-01

Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives. The activi......Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives...... innovative investigation methods and characterize the source zone hydrogeology and contamination to obtain an improved conceptual understanding of DNAPL source zone architecture in clay till and bryozoan limestone bedrock. Approach/Activities. A wide range of innovative and current site investigative tools...... for direct and indirect documentation and/or evaluation of DNAPL presence were combined in a multiple lines of evidence approach. Results/Lessons Learned. Though no single technique was sufficient for characterization of DNAPL source zone architecture, the combined use of membrane interphase probing (MIP...

Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru

Science.gov (United States)

Thouret, J.-C.; Enjolras, G.; Martelli, K.; Santoni, O.; Luque, J. A.; Nagata, M.; Arguedas, A.; Macedo, L.

2013-02-01

Arequipa, the second largest city in Peru, is exposed to many natural hazards, most notably earthquakes, volcanic eruptions, landslides, lahars (volcanic debris flows), and flash floods. Of these, lahars and flash floods, triggered by occasional torrential rainfall, pose the most frequently occurring hazards that can affect the city and its environs, in particular the areas containing low-income neighbourhoods. This paper presents and discusses criteria for delineating areas prone to flash flood and lahar hazards, which are localized along the usually dry (except for the rainy season) ravines and channels of the Río Chili and its tributaries that dissect the city. Our risk-evaluation study is based mostly on field surveys and mapping, but we also took into account quality and structural integrity of buildings, available socio-economic data, and information gained from interviews with risk-managers officials. In our evaluation of the vulnerability of various parts of the city, in addition to geological and physical parameters, we also took into account selected socio-economic parameters, such as the educational and poverty level of the population, unemployment figures, and population density. In addition, we utilized a criterion of the "isolation factor", based on distances to access emergency resources (hospitals, shelters or safety areas, and water) in each city block. By combining the hazard, vulnerability and exposure criteria, we produced detailed risk-zone maps at the city-block scale, covering the whole city of Arequipa and adjacent suburbs. Not surprisingly, these maps show that the areas at high risk coincide with blocks or districts with populations at low socio-economic levels. Inhabitants at greatest risk are the poor recent immigrants from rural areas who live in unauthorized settlements in the outskirts of the city in the upper parts of the valleys. Such settlements are highly exposed to natural hazards and have little access to vital resources. Our

Vapor Intrusion Estimation Tool for Unsaturated Zone Contaminant Sources. User’s Guide

Science.gov (United States)

2016-08-30

estimation process when applying the tool. The tool described here is focused on vapor-phase diffusion from the current vadose zone source , and is not...from the current defined vadose zone source ). The estimated soil gas contaminant concentration obtained from the pre-modeled scenarios for a building...need a full site-specific numerical model to assess the impacts beyond the current vadose zone source . 35 5.0 References Brennan, R.A., N

FLOOD MENACE IN KADUNA METROPOLIS: IMPACTS ...

African Journals Online (AJOL)

Dr A.B.Ahmed

damage, causes of flooding, human response to flooding and severity of ... from moving out. Source of ... Man responds to flood hazards through adjustment, flood abatement ... action to minimize or ameliorate flood hazards; flood abatement.

Flood Impacts on People: from Hazard to Risk Maps

Science.gov (United States)

Arrighi, C.; Castelli, F.

2017-12-01

The mitigation of adverse consequences of floods on people is crucial for civil protection and public authorities. According to several studies, in the developed countries the majority of flood-related fatalities occurs due to inappropriate high risk behaviours such as driving and walking in floodwaters. In this work both the loss of stability of vehicles and pedestrians in floodwaters are analysed. Flood hazard is evaluated, based on (i) a 2D inundation model of an urban area, (ii) 3D hydrodynamic simulations of water flows around vehicles and human body and (iii) a dimensional analysis of experimental activity. Exposure and vulnerability of vehicles and population are assessed exploiting several sources of open GIS data in order to produce risk maps for a testing case study. The results show that a significant hazard to vehicles and pedestrians exists in the study area. Particularly high is the hazard to vehicles, which are likely to be swept away by flood flow, possibly aggravate damages to structures and infrastructures and locally alter the flood propagation. Exposure and vulnerability analysis identifies some structures such as schools and public facilities, which may attract several people. Moreover, some shopping facilities in the area, which attract both vehicular and pedestrians' circulation are located in the highest flood hazard zone.The application of the method demonstrates that, at municipal level, such risk maps can support civil defence strategies and education to active citizenship, thus contributing to flood impact reduction to population.

Flood-controlled excess-air formation favors aerobic respiration and limits denitrification activity in riparian groundwater

Directory of Open Access Journals (Sweden)

Simone ePeter

2015-11-01

Full Text Available The saturated riparian zones of rivers act as spatially and temporally variable biogeochemical reactors. This complicates the assessment of biogeochemical transport and transformation processes. During a flood event, excess-air formation, i.e. the inclusion and dissolution of air bubbles into groundwater, can introduce high amounts of dissolved O2 and thereby affect biogeochemical processes in groundwater. With the help of a field-installed membrane-inlet mass-spectrometer we resolved the effects of flood induced excess-air formationon organic carbon and nitrogen transformations in groundwater of different riparian zones of a restored section of the River Thur, Switzerland. The results show that the flood event triggered high aerobic respiration activity in the groundwater below a zone densely populated with willow plants. The flood introduced high concentrations of O2 (230 µmol L–1 to the groundwater through the formation of excess air and transported up to ~400 µmol L 1 organic carbon from the soil/root layer into groundwater during the movement of the water table. A rapid respiration process, quantified via the measurements of O2, CO2 and noble-gas concentrations, led to fast depletion of the introduced O2 and organic carbon and to high CO2 concentration (590 µmol L–1 in the groundwater shortly after the flood. The synchronous analysis of different nitrogen species allowed studying the importance of denitrification activity. The results indicate that in the willow zone excess-air formation inhibited denitrification through high O2 concentration input. Instead, the observed decrease in nitrate concentration (~50 µmol N L 1 may be related to fostered nitrate uptake by plants. In the other riparian zones closer to the river, no significant excess-air formation and corresponding respiration activity was observed. Overall, analyzing the dissolved gases in the groundwater significantly contributed to deciphering biogeochemical processes in

Urbanization and climate change implications in flood risk management: Developing an efficient decision support system for flood susceptibility mapping.

Science.gov (United States)

Mahmoud, Shereif H; Gan, Thian Yew

2018-04-26

The effects of urbanization and climate change impact to the flood risk of two governorates in Egypt were analyzed. Non-parametric change point and trend detection algorithms were applied to the annual rainfall, rainfall anomaly, and temperature anomaly of both study sites. Next, change points and trends of the annual and monthly surface runoff data generated by the Curve Number method over 1948-2014 were also analyzed to detect the effects of urbanization on the surface runoff. Lastly, a GIS decision support system was developed to delineate flood susceptibility zones for the two governorates. The significant decline in annual rainfall and rainfall anomaly after 1994 at 8.96 and 15.3 mm/decade respectively was likely due to climate change impact, especially significant warming trend since 1976 at 0.16 °C/decade, though that could partly be attributed to rapid urbanization. Since 1970, effects of urbanization to flood risk are clear, because despite a decline in rainfall, the annual surface runoff and runoff anomaly show positive trends of 12.7 and of 14.39 mm/decade, respectively. Eleven flood contributing factors have been identified and used in mapping flood susceptibility zones of both sites. In the El-Beheira governorate, 9.2%, 17.9%, 32.3%, 28.3% and 12.3% of its area are categorized as very high, high, moderate, low and very low susceptibility to flooding, respectively. Similarly, in Alexandria governorate, 15.9%, 33.5%, 41%, 8.8% and 0.8% of its area are categorized as very high, high, moderate, low and very low susceptibility to flooding, respectively. Very high and high susceptible zones are located in the northern, northwestern and northeastern parts of the Beheira governorates, and in the northeastern and northwestern parts of Alexandria. The flood related information obtained in this study will be useful to assist mitigating potential flood damages and future land use planning of both governorates of Egypt. Copyright © 2018 Elsevier B.V. All

Smoky River coal flood risk mapping study

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-06-01

The Canada-Alberta Flood Damage Reduction Program (FDRP) is designed to reduce flood damage by identifying areas susceptible to flooding and by encouraging application of suitable land use planning, zoning, and flood preparedness and proofing. The purpose of this study is to define flood risk and floodway limits along the Smoky River near the former Smoky River Coal (SRC) plant. Alberta Energy has been responsible for the site since the mine and plant closed in 2000. The study describes flooding history, available data, features of the river and valley, calculation of flood levels, and floodway determination, and includes flood risk maps. The HEC-RAS program is used for the calculations. The flood risk area was calculated using the 1:100 year return period flood as the hydrological event. 7 refs., 11 figs., 7 tabs., 3 apps.

Multi-source data fusion and modeling to assess and communicate complex flood dynamics to support decision-making for downstream areas of dams: The 2011 hurricane irene and schoharie creek floods, NY

Science.gov (United States)

Renschler, Chris S.; Wang, Zhihao

2017-10-01

In light of climate and land use change, stakeholders around the world are interested in assessing historic and likely future flood dynamics and flood extents for decision-making in watersheds with dams as well as limited availability of stream gages and costly technical resources. This research evaluates an assessment and communication approach of combining GIS, hydraulic modeling based on latest remote sensing and topographic imagery by comparing the results to an actual flood event and available stream gages. On August 28th 2011, floods caused by Hurricane Irene swept through a large rural area in New York State, leaving thousands of people homeless, devastating towns and cities. Damage was widespread though the estimated and actual floods inundation and associated return period were still unclear since the flooding was artificially increased by flood water release due to fear of a dam break. This research uses the stream section right below the dam between two stream gages North Blenheim and Breakabeen along Schoharie Creek as a case study site to validate the approach. The data fusion approach uses a GIS, commonly available data sources, the hydraulic model HEC-RAS as well as airborne LiDAR data that were collected two days after the flood event (Aug 30, 2011). The aerial imagery of the airborne survey depicts a low flow event as well as the evidence of the record flood such as debris and other signs of damage to validate the hydrologic simulation results with the available stream gauges. Model results were also compared to the official Federal Emergency Management Agency (FEMA) flood scenarios to determine the actual flood return period of the event. The dynamic of the flood levels was then used to visualize the flood and the actual loss of the Old Blenheim Bridge using Google Sketchup. Integration of multi-source data, cross-validation and visualization provides new ways to utilize pre- and post-event remote sensing imagery and hydrologic models to better

Sources of uncertanity as a basis to fill the information gap in a response to flood

Science.gov (United States)

Kekez, Toni; Knezic, Snjezana

2016-04-01

Taking into account uncertainties in flood risk management remains a challenge due to difficulties in choosing adequate structural and/or non-structural risk management options. Despite stated measures wrong decisions are often being made when flood occurs. Parameter and structural uncertainties which include model and observation errors as well as lack of knowledge about system characteristics are the main considerations. Real time flood risk assessment methods are predominantly based on measured water level values and vulnerability as well as other relevant characteristics of flood affected area. The goal of this research is to identify sources of uncertainties and to minimize information gap between the point where the water level is measured and the affected area, taking into consideration main uncertainties that can affect risk value at the observed point or section of the river. Sources of uncertainties are identified and determined using system analysis approach and relevant uncertainties are included in the risk assessment model. With such methodological approach it is possible to increase response time with more effective risk assessment which includes uncertainty propagation model. Response phase could be better planned with adequate early warning systems resulting in more time and less costs to help affected areas and save human lives. Reliable and precise information is necessary to raise emergency operability level in order to enhance safety of citizens and reducing possible damage. The results of the EPISECC (EU funded FP7) project are used to validate potential benefits of this research in order to improve flood risk management and response methods. EPISECC aims at developing a concept of a common European Information Space for disaster response which, among other disasters, considers the floods.

Dynamics of flood water infiltration and ground water recharge in hyperarid desert.

Science.gov (United States)

Dahan, Ofer; Tatarsky, Boaz; Enzel, Yehouda; Kulls, Christoph; Seely, Mary; Benito, Gererdo

2008-01-01

A study on flood water infiltration and ground water recharge of a shallow alluvial aquifer was conducted in the hyperarid section of the Kuiseb River, Namibia. The study site was selected to represent a typical desert ephemeral river. An instrumental setup allowed, for the first time, continuous monitoring of infiltration during a flood event through the channel bed and the entire vadose zone. The monitoring system included flexible time domain reflectometry probes that were designed to measure the temporal variation in vadose zone water content and instruments to concurrently measure the levels of flood and ground water. A sequence of five individual floods was monitored during the rainy season in early summer 2006. These newly generated data served to elucidate the dynamics of flood water infiltration. Each flood initiated an infiltration event which was expressed in wetting of the vadose zone followed by a measurable rise in the water table. The data enabled a direct calculation of the infiltration fluxes by various independent methods. The floods varied in their stages, peaks, and initial water contents. However, all floods produced very similar flux rates, suggesting that the recharge rates are less affected by the flood stages but rather controlled by flow duration and available aquifer storage under it. Large floods flood the stream channel terraces and promote the larger transmission losses. These, however, make only a negligible contribution to the recharge of the ground water. It is the flood duration within the active streambed, which may increase with flood magnitude that is important to the recharge process.

Sex-specific responses to winter flooding, spring waterlogging and post-flooding recovery in Populus deltoides.

Science.gov (United States)

Miao, Ling-Feng; Yang, Fan; Han, Chun-Yu; Pu, Yu-Jin; Ding, Yang; Zhang, Li-Jia

2017-05-31

Winter flooding events are common in some rivers and streams due to dam constructions, and flooding and waterlogging inhibit the growth of trees in riparian zones. This study investigated sex-specific morphological, physiological and ultrastructural responses to various durations of winter flooding and spring waterlogging stresses, and post-flooding recovery characteristics in Populus deltoides. There were no significant differences in the morphological, ultrastructural and the majority of physiological traits in trees subjected to medium and severe winter flooding stresses, suggesting that males and females of P. deltoides were winter flooding tolerant, and insensitive to winter flooding duration. Males were more tolerant to winter flooding stress in terms of photosynthesis and chlorophyll fluorescence than females. Females displayed greater oxidative damage due to flooding stress than males. Males developed more efficient antioxidant enzymatic systems to control reactive oxygen species. Both sexes had similarly strong post-flooding recovery capabilities in terms of plant growth, and physiological and ultrastructural parameters. However, Males had better recovery capabilities in terms of pigment content. These results increase the understanding of poplars's adaptation to winter flooding stress. They also elucidate sex-specific differences in response to flooding stress during the dormant season, and during post-flooding recovery periods.

Flood maps in Europe - methods, availability and use

Science.gov (United States)

de Moel, H.; van Alphen, J.; Aerts, J. C. J. H.

2009-03-01

To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC) at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries), but flood depth maps are also regularly created (in seven countries). Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland) where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries already have a good starting point to map

Historical flood data series of Eastern Spanish Coast (14th-20th centuries). Improving identification of climatic patterns and human factors of flood events from primary documentary sources

Science.gov (United States)

Alberola, Armando; Barriendos, Mariano; Gil-Guirado, Salvador; Pérez-Morales, Alfredo; Balasch, Carles; Castelltort, Xavier; Mazón, Jordi; Pino, David; Lluís Ruiz-Bellet, Josep; Tuset, Jordi

2016-04-01

Historical flood data series of Eastern Spanish Coast (14th-20th centuries). Improving identification of climatic patterns and human factors of flood events from primary documentary sources Armando Alberola, Barriendos, M., Gil-Guirado, S., Pérez Morales, A., Balasch, C., Castelltort, X., Mazón, J., Pino, D., Ruiz-Bellet, J.L., Tuset, J. Historical flood events in eastern spanish coast have been studied by different research groups and projects. Complexity of flood processes, involving atmospheric, surface and human factors, is not easily understandable when long time series are required. Present analysis from PREDIFLOOD Project Consortium defines a new step of flood event databases: Improved access to primary (documentary) and secondary (bibliographical) sources, data collection for all possible locations where floods are detected, and improved system of classification (Barriendos et al., 2014). A first analysis is applied to 8 selected flood series. Long chronologies from PREDIFLOOD Project for Catalonia region (Girona, Barcelona, Tarragona, Lleida, Tortosa). In addition, to cover all sector of spanish mediterranean coast, we introduce Valencia city in Turia River basin. South Eastern sector is cover with Murcia and Caravaca cities, Segura River basin. Extension of area under study required contributions of research teams experienced in work of documentary primary sources (Alberola, 2006; Gil-Guirado, 2013). Flood frequency analysis for long scale periods show natural climatic oscillations into so-called Little Ice Age. There are general patterns, affecting most of basins, but also some local anomalies or singularities. To explain these differences and analogies it is not enough to use purely climatic factors. In this way, we analyze human factors that have been able to influence the variability of floods along last 6 centuries (demography, hydraulic infrastructures, urban development...). This approach improves strongly understanding of mechanisms producing

Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru

Directory of Open Access Journals (Sweden)

J.-C. Thouret

2013-02-01

Full Text Available Arequipa, the second largest city in Peru, is exposed to many natural hazards, most notably earthquakes, volcanic eruptions, landslides, lahars (volcanic debris flows, and flash floods. Of these, lahars and flash floods, triggered by occasional torrential rainfall, pose the most frequently occurring hazards that can affect the city and its environs, in particular the areas containing low-income neighbourhoods. This paper presents and discusses criteria for delineating areas prone to flash flood and lahar hazards, which are localized along the usually dry (except for the rainy season ravines and channels of the Río Chili and its tributaries that dissect the city. Our risk-evaluation study is based mostly on field surveys and mapping, but we also took into account quality and structural integrity of buildings, available socio-economic data, and information gained from interviews with risk-managers officials.

In our evaluation of the vulnerability of various parts of the city, in addition to geological and physical parameters, we also took into account selected socio-economic parameters, such as the educational and poverty level of the population, unemployment figures, and population density. In addition, we utilized a criterion of the "isolation factor", based on distances to access emergency resources (hospitals, shelters or safety areas, and water in each city block. By combining the hazard, vulnerability and exposure criteria, we produced detailed risk-zone maps at the city-block scale, covering the whole city of Arequipa and adjacent suburbs. Not surprisingly, these maps show that the areas at high risk coincide with blocks or districts with populations at low socio-economic levels. Inhabitants at greatest risk are the poor recent immigrants from rural areas who live in unauthorized settlements in the outskirts of the city in the upper parts of the valleys. Such settlements are highly exposed to natural hazards and have little access

Legitimizing differentiated flood protection levels

NARCIS (Netherlands)

Thomas, Hartmann; Spit, Tejo

2016-01-01

The European flood risk management plan is a new instrument introduced by the Floods Directive. It introduces a spatial turn and a scenario approach in flood risk management, ultimately leading to differentiated flood protection levels on a catchment basis. This challenges the traditional sources of

Hiding the Source Based on Limited Flooding for Sensor Networks.

Science.gov (United States)

Chen, Juan; Lin, Zhengkui; Hu, Ying; Wang, Bailing

2015-11-17

Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results.

Evaluation of Long-term Performance of Enhanced Anaerobic Source Zone Bioremediation using mass flux

Science.gov (United States)

Haluska, A.; Cho, J.; Hatzinger, P.; Annable, M. D.

2017-12-01

Chlorinated ethene DNAPL source zones in groundwater act as potential long term sources of contamination as they dissolve yielding concentrations well above MCLs, posing an on-going public health risk. Enhanced bioremediation has been applied to treat many source zones with significant promise, but long-term sustainability of this technology has not been thoroughly assessed. This study evaluated the long-term effectiveness of enhanced anaerobic source zone bioremediation at chloroethene contaminated sites to determine if the treatment prevented contaminant rebound and removed NAPL from the source zone. Long-term performance was evaluated based on achieving MCL-based contaminant mass fluxes in parent compound concentrations during different monitoring periods. Groundwater concertation versus time data was compiled for 6-sites and post-remedial contaminant mass flux data was then measured using passive flux meters at wells both within and down-gradient of the source zone. Post-remedial mass flux data was then combined with pre-remedial water quality data to estimate pre-remedial mass flux. This information was used to characterize a DNAPL dissolution source strength function, such as the Power Law Model and the Equilibrium Stream tube model. The six-sites characterized for this study were (1) Former Charleston Air Force Base, Charleston, SC; (2) Dover Air Force Base, Dover, DE; (3) Treasure Island Naval Station, San Francisco, CA; (4) Former Raritan Arsenal, Edison, NJ; (5) Naval Air Station, Jacksonville, FL; and, (6) Former Naval Air Station, Alameda, CA. Contaminant mass fluxes decreased for all the sites by the end of the post-treatment monitoring period and rebound was limited within the source zone. Post remedial source strength function estimates suggest that decreases in contaminant mass flux will continue to occur at these sites, but a mass flux based on MCL levels may never be exceeded. Thus, site clean-up goals should be evaluated as order

iFLOOD: A Real Time Flood Forecast System for Total Water Modeling in the National Capital Region

Science.gov (United States)

Sumi, S. J.; Ferreira, C.

2017-12-01

Extreme flood events are the costliest natural hazards impacting the US and frequently cause extensive damages to infrastructure, disruption to economy and loss of lives. In 2016, Hurricane Matthew brought severe damage to South Carolina and demonstrated the importance of accurate flood hazard predictions that requires the integration of riverine and coastal model forecasts for total water prediction in coastal and tidal areas. The National Weather Service (NWS) and the National Ocean Service (NOS) provide flood forecasts for almost the entire US, still there are service-gap areas in tidal regions where no official flood forecast is available. The National capital region is vulnerable to multi-flood hazards including high flows from annual inland precipitation events and surge driven coastal inundation along the tidal Potomac River. Predicting flood levels on such tidal areas in river-estuarine zone is extremely challenging. The main objective of this study is to develop the next generation of flood forecast systems capable of providing accurate and timely information to support emergency management and response in areas impacted by multi-flood hazards. This forecast system is capable of simulating flood levels in the Potomac and Anacostia River incorporating the effects of riverine flooding from the upstream basins, urban storm water and tidal oscillations from the Chesapeake Bay. Flood forecast models developed so far have been using riverine data to simulate water levels for Potomac River. Therefore, the idea is to use forecasted storm surge data from a coastal model as boundary condition of this system. Final output of this validated model will capture the water behavior in river-estuary transition zone far better than the one with riverine data only. The challenge for this iFLOOD forecast system is to understand the complex dynamics of multi-flood hazards caused by storm surges, riverine flow, tidal oscillation and urban storm water. Automated system

Influence of spreading urbanization in flood areas on flood damage in Slovenia

International Nuclear Information System (INIS)

Komac, B; Zorn, M; Natek, K

2008-01-01

Damage caused by natural disasters in Slovenia is frequently linked to the ignoring of natural factors in spatial planning. Historically, the construction of buildings and settlements avoided dangerous flood areas, but later we see increasing construction in dangerous areas. During the floods in 1990, the most affected buildings were located on ill-considered locations, and the majority was built in more recent times. A similar situation occurred during the floods of September 2007. Comparing the effects of these floods, we determined that damage was always greater due to the urbanization of flood areas. This process furthermore increasingly limits the 'manoeuvring space' for water management authorities, who due to the torrential nature of Slovenia's rivers can not ensure the required level of safety from flooding for unsuitably located settlements and infrastructure. Every year, the Environmental Agency of the Republic of Slovenia issues more than one thousand permits for interventions in areas that affect the water regime, and through decrees the government allows construction in riparian zones, which is supposedly forbidden by the Law on Water. If we do not take measures with more suitable policies for spatial planning, we will no long have the possibility in future to reduce the negative consequences of floods. Given that torrential floods strike certain Slovene regions every three years on average and that larger floods occur at least once a decade, it is senseless to lay the blame on climate change.

Oxygenated gasoline release in the unsaturated zone - Part 1: Source zone behavior.

Science.gov (United States)

Freitas, Juliana G; Barker, James F

2011-11-01

Oxygenates present in gasoline, such as ethanol and MTBE, are a concern in subsurface contamination related to accidental spills. While gasoline hydrocarbon compounds have low solubility, MTBE and ethanol are more soluble, ethanol being completely miscible with water. Consequently, their fate in the subsurface is likely to differ from that of gasoline. To evaluate the fate of gasoline containing oxygenates following a release in the unsaturated zone shielded from rainfall/recharge, a controlled field test was performed at Canadian Forces Base Borden, in Ontario. 200L of a mixture composed of gasoline with 10% ethanol and 4.5% MTBE was released in the unsaturated zone, into a trench 20cm deep, about 32cm above the water table. Based on soil cores, most of the ethanol was retained in the source, above the capillary fringe, and remained there for more than 100 days. Ethanol partitioned from the gasoline to the unsaturated pore-water and was retained, despite the thin unsaturated zone at the site (~35cm from the top of the capillary fringe to ground surface). Due to its lower solubility, most of the MTBE remained within the NAPL as it infiltrated deeper into the unsaturated zone and accumulated with the gasoline on top of the depressed capillary fringe. Only minor changes in the distribution of ethanol were noted following oscillations in the water table. Two methods to estimate the capacity of the unsaturated zone to retain ethanol are explored. It is clear that conceptual models for sites impacted by ethanol-fuels must consider the unsaturated zone. Copyright © 2011 Elsevier B.V. All rights reserved.

Flood maps in Europe – methods, availability and use

Directory of Open Access Journals (Sweden)

J. C. J. H. Aerts

2009-03-01

Full Text Available To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries, but flood depth maps are also regularly created (in seven countries. Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries already have a good starting

Assessing the Effects of Periodic Flooding on the Population Structure and Recruitment Rates of Riparian Tree Forests

Directory of Open Access Journals (Sweden)

Jean-Sébastien Berthelot

2014-08-01

Full Text Available Riparian forest stands are subjected to a variety of hydrological stresses as a result of annual fluctuations in water levels during the growing season. Spring floods create additional water-related stress as a result of a major inflow of water that floods riverside land. This exploratory study assesses the impacts of successive floods on tree dynamics and regeneration in an active sedimentation area, while determining the age of the stands using the recruitment rates, tree structure and tree rings based on dendrochronological analysis. Environmental data were also recorded for each vegetation quadrat. In total, 2633 tree stems were tallied throughout the quadrats (200 m2, and tree specimens were analyzed based on the various flood zones. A total of 720 specimens were counted (100 m2 strip to measure natural regeneration. Higher recruitment rates are noted for the no-flood zones and lower rates in active floodplains. During the period of the establishment of tree species, the survival rates are comparable between the flood zones and the no-flood zones. Tree diameter distribution reveals a strong predominance of young trees in flooded areas. Different factors appear to come into play in the dynamics of riparian forest stands, including the disruptions associated with successive flooding.

Hiding the Source Based on Limited Flooding for Sensor Networks

Directory of Open Access Journals (Sweden)

Juan Chen

2015-11-01

Full Text Available Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results.

Analysis of the flood extent extraction model and the natural flood influencing factors: A GIS-based and remote sensing analysis

International Nuclear Information System (INIS)

Lawal, D U; Matori, A N; Yusuf, K W; Hashim, A M; Balogun, A L

2014-01-01

Serious floods have hit the State of Perlis in 2005, 2010, as well as 2011. Perlis is situated in the northern part of Peninsula Malaysia. The floods caused great damage to properties and human lives. There are various methods used in an attempt to provide the most reliable ways to reduce the flood risk and damage to the optimum level by identifying the flood vulnerable zones. The purpose of this paper is to develop a flood extent extraction model based on Minimum Distance Algorithm and to overlay with the natural flood influencing factors considered herein in order to examine the effect of each factor in flood generation. GIS spatial database was created from a geological map, SPOT satellite image, and the topographical map. An attribute database was equally created from field investigations and historical flood areas reports of the study area. The results show a great correlation between the flood extent extraction model and the flood factors

FloodProBE: technologies for improved safety of the built environment in relation to flood events

International Nuclear Information System (INIS)

Ree, C.C.D.F. van; Van, M.A.; Heilemann, K.; Morris, M.W.; Royet, P.; Zevenbergen, C.

2011-01-01

The FloodProBE project started as a FP7 research project in November 2009. Floods, together with wind related storms, are considered the major natural hazard in the EU in terms of risk to people and assets. In order to adapt urban areas (in river and coastal zones) to prevent flooding or to be better prepared for floods, decision makers need to determine how to upgrade flood defences and increasing flood resilience of protected buildings and critical infrastructure (power supplies, communications, water, transport, etc.) and assess the expected risk reduction from these measures. The aim of the FloodProBE-project is to improve knowledge on flood resilience and flood protection performance for balancing investments in flood risk management in urban areas. To this end, technologies, methods and tools for assessment purposes and for the adaptation of new and existing buildings and critical infrastructure are developed, tested and disseminated. Three priority areas are addressed by FloodProBE. These are: (i) vulnerability of critical infrastructure and high-density value assets including direct and indirect damage, (ii) the assessment and reliability of urban flood defences including the use of geophysical methods and remote sensing techniques and (iii) concepts and technologies for upgrading weak links in flood defences as well as construction technologies for flood proofing buildings and infrastructure networks to increase the flood resilience of the urban system. The primary impact of FloodProBE in advancing knowledge in these areas is an increase in the cost-effectiveness (i.e. performance) of new and existing flood protection structures and flood resilience measures.

Pesticide-soil microflora interactions in flooded rice soils

International Nuclear Information System (INIS)

Sethunathan, N.; Siddaramappa, R.; Siddarame Gowda, T.K.; Rajaram, K.P.; Barik, S.; Rao, V.R.

1976-01-01

Isotope studies revealed that gamma and beta isomers of HCH (hexachlorocyclohexane) decomposed rapidly in nonsterile soils capable of attaining redox potentials of -40 to -100mV within 20 days after flooding. Degradation was slow, however, in soils low in organic matter and in soils with extremely low pH and positive potentials, even after several weeks of flooding. Under flooded conditions, endrin decomposed to six metabolites in most soils. There is evidence that biological hydrolysis of parathion is more widespread than hitherto believed, particularly under flooded soil conditions. Applications of benomyl (fungicide) to a simulated-oxidized zone of flooded soils favoured heterotrophic nitrification. (author)

Economic Assessment of Flood Control Facilities under Climate Uncertainty: A Case of Nakdong River, South Korea

Directory of Open Access Journals (Sweden)

Kyeongseok Kim

2018-01-01

Full Text Available Climate change contributes to enhanced flood damage that has been increasing for the last several decades. Understanding climate uncertainties improves adaptation strategies used for investment in flood control facilities. This paper proposes an investment decision framework for one flood zone to cope with future severe climate impacts. This framework can help policy-makers investigate the cost of future damage and conduct an economic assessment using real options under future climate change scenarios. The proposed methodology provides local municipalities with an adaptation strategy for flood control facilities in a flood zone. Using the proposed framework, the flood prevention facilities in the Nakdong River Basin of South Korea was selected as a case study site to analyze the economic assessment of the investments for flood control facilities. Using representative concentration pathway (RCP climate scenarios, the cost of future flood damage to 23 local municipalities was calculated, and investment strategies for adaptation were analyzed. The project option value was determined by executing an option to invest in an expansion that would adapt to floods under climate change. The results of the case study showed that the proposed flood facilities are economically feasible under both scenarios used. The framework is anticipated to present guidance for establishing investment strategies for flood control facilities of a flood zone in multiple municipalities’ settings.

Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China.

Science.gov (United States)

Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y Jun

2016-01-01

Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region.

Mass Transfer Limited Enhanced Bioremediation at Dnapl Source Zones: a Numerical Study

Science.gov (United States)

Kokkinaki, A.; Sleep, B. E.

2011-12-01

The success of enhanced bioremediation of dense non-aqueous phase liquids (DNAPLs) relies on accelerating contaminant mass transfer from the organic to the aqueous phase, thus enhancing the depletion of DNAPL source zones compared to natural dissolution. This is achieved by promoting biological activity that reduces the contaminant's aqueous phase concentration. Although laboratory studies have demonstrated that high reaction rates are attainable by specialized microbial cultures in DNAPL source zones, field applications of the technology report lower reaction rates and prolonged remediation times. One possible explanation for this phenomenon is that the reaction rates are limited by the rate at which the contaminant partitions from the DNAPL to the aqueous phase. In such cases, slow mass transfer to the aqueous phase reduces the bioavailability of the contaminant and consequently decreases the potential source zone depletion enhancement. In this work, the effect of rate limited mass transfer on bio-enhanced dissolution of DNAPL chlorinated ethenes is investigated through a numerical study. A multi-phase, multi-component groundwater transport model is employed to simulate DNAPL mass depletion for a range of source zone scenarios. Rate limited mass transfer is modeled by a linear driving force model, employing a thermodynamic approach for the calculation of the DNAPL - water interfacial area. Metabolic reductive dechlorination is modeled by Monod kinetics, considering microbial growth and self-inhibition. The model was utilized to identify conditions in which mass transfer, rather than reaction, is the limiting process, as indicated by the bioavailability number. In such cases, reaction is slower than expected, and further increase in the reaction rate does not enhance mass depletion. Mass transfer rate limitations were shown to affect both dechlorination and microbial growth kinetics. The complex dynamics between mass transfer, DNAPL transport and distribution, and

Floods of the Lower Tisza from the late 17th century onwards: frequency, magnitude, seasonality and great flood events

Science.gov (United States)

Kiss, Andrea

2016-04-01

The present paper is based on a recently developed database including contemporary original, administrative, legal and private source materials (published and archival) as well as media reports related to the floods occurred on the lower sections of the Tisza river in Hungary, with special emphasis on the area of Szeged town. The study area is well-represented by contemporary source evidence from the late 17th century onwards, when the town and its broader area was reoccupied from the Ottoman Turkish Empire. Concerning the applied source materials, the main bases of investigation are the administrative (archival) sources such as town council protocols of Szeged and county meeting protocols of Csanád and Csongrád Counties. In these (legal-)administrative documents damaging events (natural/environmental hazards) were systematically recorded. Moreover, other source types such as taxation-related damage accounts as well as private and official reports, letters and correspondence (published, unpublished) were also included. Concerning published evidence, a most important source is flood reports in contemporary newspapers as well as town chronicles and other contemporary narratives. In the presentation the main focus is on the analysis of flood-rich flood-poor periods of the last ca. 330 years; moreover, the seasonality distribution as well as the magnitude of Tisza flood events are also discussed. Another important aim of the poster is to provide a short overview, in the form of case studies, on the greatest flood events (e.g. duration, magnitude, damages, multi-annual consequences), and their further impacts on the urban and countryside development as well as on (changes in) flood defence strategies. In this respect, especially two flood events, the great (1815-)1816 and the catastrophic 1879 flood (shortly with causes and consequences) - that practically erased Szeged town from the ground - are presented in more detail.

Floods in Colorado

Science.gov (United States)

Follansbee, Robert; Sawyer, Leon R.

1948-01-01

The first records of floods in Colorado antedated the settlement of the State by about 30 years. These were records of floods on the Arkansas and Republican Rivers in 1826. Other floods noted by traders, hunters and emigrants, some of whom were on their way to the Far West, occurred in 1844 on the Arkansas River, and by inference on the South Platte River. Other early floods were those on the Purgatoire, the Lower Arkansas, and the San Juan Rivers about 1859. The most serious flood since settlement began was that on the Arkansas River during June 1921, which caused the loss of about 100 lives and an estimated property loss of $19,000,000. Many floods of lesser magnitude have occurred, and some of these have caused loss of life and very considerable property damage. Topography is the chief factor in determining the location of storms and resulting floods. These occur most frequently on the eastern slope of the Front Range. In the mountains farther west precipitation is insufficient to cause floods except during periods of melting snow, in June. In the southwestern part of the State, where precipitation during periods of melting snow is insufficient to cause floods, the severest floods yet experienced resulted from heavy rains in September 1909 and October 1911. In the eastern foothills region, usually below an altitude of about 7,500 feet and extending for a distance of about 50 miles east of the mountains, is a zone subject to rainfalls of great intensity known as cloudbursts. These cloudbursts are of short duration and are confined to very small areas. At times the intensity is so great as to make breathing difficult for those exposed to a storm. The areas of intense rainfall are so small that Weather Bureau precipitation stations have not been located in them. Local residents, being cloudburst conscious, frequently measure the rainfall in receptacles in their yards, and such records constitute the only source of information regarding the intensity. A flood

Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China

Science.gov (United States)

Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y. Jun

2016-01-01

Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region. PMID:27097325

Assessing the impact of different sources of topographic data on 1-D hydraulic modelling of floods

Science.gov (United States)

Ali, A. Md; Solomatine, D. P.; Di Baldassarre, G.

2015-01-01

Topographic data, such as digital elevation models (DEMs), are essential input in flood inundation modelling. DEMs can be derived from several sources either through remote sensing techniques (spaceborne or airborne imagery) or from traditional methods (ground survey). The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the Shuttle Radar Topography Mission (SRTM), the light detection and ranging (lidar), and topographic contour maps are some of the most commonly used sources of data for DEMs. These DEMs are characterized by different precision and accuracy. On the one hand, the spatial resolution of low-cost DEMs from satellite imagery, such as ASTER and SRTM, is rather coarse (around 30 to 90 m). On the other hand, the lidar technique is able to produce high-resolution DEMs (at around 1 m), but at a much higher cost. Lastly, contour mapping based on ground survey is time consuming, particularly for higher scales, and may not be possible for some remote areas. The use of these different sources of DEM obviously affects the results of flood inundation models. This paper shows and compares a number of 1-D hydraulic models developed using HEC-RAS as model code and the aforementioned sources of DEM as geometric input. To test model selection, the outcomes of the 1-D models were also compared, in terms of flood water levels, to the results of 2-D models (LISFLOOD-FP). The study was carried out on a reach of the Johor River, in Malaysia. The effect of the different sources of DEMs (and different resolutions) was investigated by considering the performance of the hydraulic models in simulating flood water levels as well as inundation maps. The outcomes of our study show that the use of different DEMs has serious implications to the results of hydraulic models. The outcomes also indicate that the loss of model accuracy due to re-sampling the highest resolution DEM (i.e. lidar 1 m) to lower resolution is much less than the loss of model accuracy due

Water sources accessed by arid zone riparian trees in highly saline environments, Australia.

Science.gov (United States)

Costelloe, Justin F; Payne, Emily; Woodrow, Ian E; Irvine, Elizabeth C; Western, Andrew W; Leaney, Fred W

2008-05-01

The flow regimes of arid zone rivers are often highly variable, and shallow groundwater in the alluvial aquifers can be very saline, thus constraining the availability and quality of the major water sources available to riparian trees-soil water, shallow groundwater and stream water. We have identified water sources and strategies used by riparian trees in more highly saline and arid conditions than previously studied for riparian trees of arid zone rivers. Our research focused on the riparian species Eucalyptus coolabah, one of the major riparian trees of ephemeral arid zone rivers in Australia. The water sources available to this riparian tree were examined using delta(18)O isotope data from xylem, soil water, groundwater and surface water. Additionally, soil chloride and matric potential data were used to infer zones of water availability for root uptake. Despite the saline conditions, the trees used a mixture of soil water and groundwater sources, but they did not use surface water directly. The study identified three strategies used to cope with typically high groundwater and soil water salinities. Firstly, the trees preferentially grow in zones of most frequent flushing by infiltrating streamflow, such as the bank-tops of channels. Secondly, the trees limit water use by having low transpiration rates. Thirdly, the trees are able to extract water at very low osmotic potentials, with water uptake continuing at chloride concentrations of at least 20,000-30,000 mg L(-1).

State-of-the-art for evaluating the potential impact of flooding on a radioactive waste repository

International Nuclear Information System (INIS)

1980-01-01

This report is a review of the state-of-the-art for evaluating the potential impact of flooding on a deep radioactive-waste repository, namely, for predicting the future occurrence of catastrophic flooding and for estimating the effect of such flooding on waste containment characteristics. Several detrimental effects are identified: flooding can increase groundwater seepage velocities through a repository within the framework of the existing hydrologic system and thus increase the rate of radioactive-waste leakage to the biosphere; flooding may alter repository hydrology by reversing flow gradients, relocating sources of groundwater recharge and discharge, or shortening seepage paths, thereby producing unpredictable leakage; saturation of a vadose-zone repository during flooding can increase groundwater seepage velocities by several orders of magnitude; and flooding can damage repository-media containment properties by inducing seismic or chemical instability or increasing fracture permeability in relatively shallow repository rock as a result of redistributing in-situ stresses. Short-term flooding frequency and magnitude can be predicted statistically by analyzing historical records of flooding. However, long-term flooding events that could damage a permanent repository cannot be predicted with confidence because the geologic record is neither unique nor sufficienly complete for statistical analysis. It is more important to identify parameters characterizing containment properties (such as permeability, groundwater gradient, and shortest seepage path length to the biosphere) that could be affected by future flooding, estimate the maximum magnitude of flooding that could occur within the life of the repository by examining the geologic record, and determine the impact such flooding could have on the parameter values

Urban Floods and Residential Rental Values Nexus in Kumasi, Ghana

African Journals Online (AJOL)

The study adopted multiple research approaches in selecting zones with both flood ... highlight the increasing evidence of negativity on houses and their values in terms of ... The potential for floods to wipeout housing wealth accumulated over ... In addition, locations do influence residential rental values through tangible or.

Flood frequency analysis of historical flood data under stationary and non-stationary modelling

Science.gov (United States)

Machado, M. J.; Botero, B. A.; López, J.; Francés, F.; Díez-Herrero, A.; Benito, G.

2015-06-01

Historical records are an important source of information on extreme and rare floods and fundamental to establish a reliable flood return frequency. The use of long historical records for flood frequency analysis brings in the question of flood stationarity, since climatic and land-use conditions can affect the relevance of past flooding as a predictor of future flooding. In this paper, a detailed 400 yr flood record from the Tagus River in Aranjuez (central Spain) was analysed under stationary and non-stationary flood frequency approaches, to assess their contribution within hazard studies. Historical flood records in Aranjuez were obtained from documents (Proceedings of the City Council, diaries, chronicles, memoirs, etc.), epigraphic marks, and indirect historical sources and reports. The water levels associated with different floods (derived from descriptions or epigraphic marks) were computed into discharge values using a one-dimensional hydraulic model. Secular variations in flood magnitude and frequency, found to respond to climate and environmental drivers, showed a good correlation between high values of historical flood discharges and a negative mode of the North Atlantic Oscillation (NAO) index. Over the systematic gauge record (1913-2008), an abrupt change on flood magnitude was produced in 1957 due to constructions of three major reservoirs in the Tagus headwaters (Bolarque, Entrepeñas and Buendia) controlling 80% of the watershed surface draining to Aranjuez. Two different models were used for the flood frequency analysis: (a) a stationary model estimating statistical distributions incorporating imprecise and categorical data based on maximum likelihood estimators, and (b) a time-varying model based on "generalized additive models for location, scale and shape" (GAMLSS) modelling, which incorporates external covariates related to climate variability (NAO index) and catchment hydrology factors (in this paper a reservoir index; RI). Flood frequency

Flow and transport in Riparian Zones

DEFF Research Database (Denmark)

Jensen, Jannick Kolbjørn

scenarios with changing conditions for flow (steady state with no flooding or transient with flooding), hydrogeology, denitrification rate, and extent of flooding it is demonstrated how flow paths, residence times, and nitrate removal are affected. With this previous conceptual models on the hydrology......The PhD study presents research results from two re-established Danish riparian zones, Brynemade and Skallebanke, located along Odense River on the island Funen, Denmark. The overall objectives of the PhD study have been to improve the understanding of flow and transport in riparian zones....... The methodology focuses on; construction of field sites along Odense River, understanding flow and transport, and performing numerical/analytical model assessments of flow and transport. An initial 2D simulation study was performed with a conceptual setup based on the Brynemade site. Through a series of 2D model...

Nannofossil and sequence chronostratigraphy of a marine flooding surface in the Turonian of Trinidad

Energy Technology Data Exchange (ETDEWEB)

Huang, T.C. [Exxon Exploration Company, Houston, TX (United States)

1996-08-01

A multi-well regional study in the Southern basin, Trinidad, reveals a very pronounced marine flooding surface in Turonian- age sediments. This surface is correlatable with global Turonian marine transgressions and genetically ties with the best hydrocarbon source rocks known in Trinidad. The Turonian marine flooding surface yields abundant nannoplankton. Most notable is Lithastrinus moratus Stover, a short-ranging marker of the Lithastrinus evolutionary series. Two morphotypes of Lithastrinus moratus have been found. The more delicate eight-rayed form evolves from Lithastrinus floralls in early Turonian time. Based on observations in Ste. Croix-1, Rocky Palace-1, Rochard-1, Marac-1, Moniga East-15, Iguana River-1, Lizard Spring-I and Antilles Brighton-102, it occurs more frequently in the lower Turonian, but is rare in Trinidad. It has a more robust seven-rayed descendant that appears to be restricted to a narrow interval associated with peak Turonian marine transgression and usually dominates the nannofossil assemblage in the condensed section. The highest stratigraphic occurrence of this form coincides with the lowest occurrence of Marthastentes furcatus based on core sample studies. The age of the marine flooding surface is therefore well constrained to be in zone CC12 and is considered to be correlative with the 89 million year marine flooding surface. The marine flooding surface appears intercontinentally correlatable as it has also been identified in the Arcadia Shale of the Eagle Ford Group in Texas. Because of its wide areal distribution and ease of paleontological recognition, this surface is ideal for regional hydrocarbon source rock mapping, stratal correlation and structural control.

RainyDay: An Online, Open-Source Tool for Physically-based Rainfall and Flood Frequency Analysis

Science.gov (United States)

Wright, D.; Yu, G.; Holman, K. D.

2017-12-01

Flood frequency analysis in ungaged or changing watersheds typically requires rainfall intensity-duration-frequency (IDF) curves combined with hydrologic models. IDF curves only depict point-scale rainfall depth, while true rainstorms exhibit complex spatial and temporal structures. Floods result from these rainfall structures interacting with watershed features such as land cover, soils, and variable antecedent conditions as well as river channel processes. Thus, IDF curves are traditionally combined with a variety of "design storm" assumptions such as area reduction factors and idealized rainfall space-time distributions to translate rainfall depths into inputs that are suitable for flood hydrologic modeling. The impacts of such assumptions are relatively poorly understood. Meanwhile, modern precipitation estimates from gridded weather radar, grid-interpolated rain gages, satellites, and numerical weather models provide more realistic depictions of rainfall space-time structure. Usage of such datasets for rainfall and flood frequency analysis, however, are hindered by relatively short record lengths. We present RainyDay, an open-source stochastic storm transposition (SST) framework for generating large numbers of realistic rainfall "scenarios." SST "lengthens" the rainfall record by temporal resampling and geospatial transposition of observed storms to extract space-time information from regional gridded rainfall data. Relatively short (10-15 year) records of bias-corrected radar rainfall data are sufficient to estimate rainfall and flood events with much longer recurrence intervals including 100-year and 500-year events. We describe the SST methodology as implemented in RainyDay and compare rainfall IDF results from RainyDay to conventional estimates from NOAA Atlas 14. Then, we demonstrate some of the flood frequency analysis properties that are possible when RainyDay is integrated with a distributed hydrologic model, including robust estimation of flood

Effect of spatial adaptation measures on flood risk: study of coastal floods in Belgium

NARCIS (Netherlands)

Koks, E.E.; de Moel, H.; Aerts, J.C.J.H.; Bouwer, L.M.

2014-01-01

Flood risk in coastal zones is projected to increase due to climate change and socioeconomic changes. Over the last decades, population growth, increases in wealth, and urban expansion have been found to be the main causes for increasing losses in coastal areas. These changes may, however, be offset

Unintentional contaminant transfer from groundwater to the vadose zone during source zone remediation of volatile organic compounds.

Science.gov (United States)

Chong, Andrea D; Mayer, K Ulrich

2017-09-01

Historical heavy use of chlorinated solvents in conjunction with improper disposal practices and accidental releases has resulted in widespread contamination of soils and groundwater in North America and worldwide. As a result, remediation of chlorinated solvents is required at many sites. For source zone treatment, common remediation strategies include in-situ chemical oxidation (ISCO) using potassium or sodium permanganate, and the enhancement of biodegradation by primary substrate addition. It is well known that these remediation methods tend to generate gas (carbon dioxide (CO 2 ) in the case of ISCO using permanganate, CO 2 and methane (CH 4 ) in the case of bioremediation). Vigorous gas generation in the presence of chlorinated solvents, which are categorized as volatile organic contaminants (VOCs), may cause gas exsolution, ebullition and stripping of the contaminants from the treatment zone. This process may lead to unintentional 'compartment transfer', whereby VOCs are transported away from the contaminated zone into overlying clean sediments and into the vadose zone. To this extent, benchtop column experiments were conducted to quantify the effect of gas generation during remediation of the common chlorinated solvent trichloroethylene (TCE/C 2 Cl 3 H). Both ISCO and enhanced bioremediation were considered as treatment methods. Results show that gas exsolution and ebullition occurs for both remediation technologies. Facilitated by ebullition, TCE was transported from the source zone into overlying clean groundwater and was subsequently released into the column headspace. For the case of enhanced bioremediation, the intermediate degradation product vinyl chloride (VC) was also stripped from the treatment zone. The concentrations measured in the headspace of the columns (TCE ∼300ppm in the ISCO column, TCE ∼500ppm and VC ∼1380ppm in the bioremediation column) indicate that substantial transfer of VOCs to the vadose zone is possible. These findings

Contribution of future urbanisation expansion to flood risk changes

Science.gov (United States)

Bruwier, Martin; Mustafa, Ahmed; Archambeau, Pierre; Erpicum, Sébastien; Pirotton, Michel; Teller, Jacques; Dewals, Benjamin

2016-04-01

The flood risk is expected to increase in the future due to climate change and urban development. Climate change modifies flood hazard and urban development influences exposure and vulnerability to floods. While the influence of climate change on flood risk has been studied widely, the impact of urban development also needs to be considered in a sustainable flood risk management approach. The main goal of this study is the determination of the sensitivity of future flood risk to different urban development scenarios at a relatively short-time horizon in the River Meuse basin in Wallonia (Belgium). From the different scenarios, the expected impact of urban development on flood risk is assessed. Three urban expansion scenarios are developed up to 2030 based on a coupled cellular automata (CA) and agent-based (AB) urban expansion model: (i) business-as-usual, (ii) restrictive and (iii) extreme expansion scenarios. The main factor controlling these scenarios is the future urban land demand. Each urban expansion scenario is developed by considering or not high and/or medium flood hazard zones as a constraint for urban development. To assess the model's performance, it is calibrated for the Meuse River valley (Belgium) to simulate urban expansion between 1990 and 2000. Calibration results are then assessed by comparing the 2000 simulated land-use map and the actual 2000 land-use map. The flood damage estimation for each urban expansion scenario is determined for five flood discharges by overlaying the inundation map resulting from a hydraulic computation and the urban expansion map and by using damage curves and specific prices. The hydraulic model Wolf2D has been extensively validated by comparisons between observations and computational results during flood event .This study focuses only on mobile and immobile prices for urban lands, which are associated to the most severe damages caused by floods along the River Meuse. These findings of this study offers tools to

Potential of arid zone vegetation as a source of substrates

Energy Technology Data Exchange (ETDEWEB)

Bassham, J.A.

1977-11-01

Three aspects of the potential of vegetation in arid zones as a source of substrates are discussed. The first includes the limitations on efficiency of conversion of solar energy to the stored chemical energy of biomass in green plants, and the subsequent biochemical pathways of carbon dioxide fixation and biosynthesis. Second is the potential of plants endogenous to arid zones. Finally, the use of covered agriculture or controlled environmental agriculture (CEA) is considered both in its present form and in terms of possible extenion to the large scale production of stable crops. (JGB)

Composite Flood Risk for Virgin Island

Science.gov (United States)

The Composite Flood Risk layer combines flood hazard datasets from Federal Emergency Management Agency (FEMA) flood zones, NOAA's Shallow Coastal Flooding, and the National Hurricane Center SLOSH model for Storm Surge inundation for category 1, 2, and 3 hurricanes.Geographic areas are represented by a grid of 10 by 10 meter cells and each cell has a ranking based on variation in exposure to flooding hazards: Moderate, High and Extreme exposure. Geographic areas in each input layers are ranked based on their probability of flood risk exposure. The logic was such that areas exposed to flooding on a more frequent basis were given a higher ranking. Thus the ranking incorporates the probability of the area being flooded. For example, even though a Category 3 storm surge has higher flooding elevations, the likelihood of the occurrence is lower than a Category 1 storm surge and therefore the Category 3 flood area is given a lower exposure ranking. Extreme exposure areas are those areas that are exposed to relatively frequent flooding.The ranked input layers are then converted to a raster for the creation of the composite risk layer by using cell statistics in spatial analysis. The highest exposure ranking for a given cell in any of the three input layers is assigned to the corresponding cell in the composite layer.For example, if an area (a cell) is rank as medium in the FEMA layer, moderate in the SLOSH layer, but extreme in the SCF layer, the cell will be considere

77 FR 46994 - Proposed Flood Elevation Determinations

Science.gov (United States)

2012-08-07

..., it addresses the following flooding sources: Jones Bayou, Mississippi River, and Porter Bayou. DATES... Incorporated Areas'' addressed the following flooding sources: Jones Bayou, Mississippi River, and Porter Bayou.... Approximately 8.1 miles None +162 upstream of the Arkansas River confluence. Porter Bayou Approximately 0.8 mile...

Internal flooding analyses results of Slovak NPPs

International Nuclear Information System (INIS)

Sopira, Vladimir

2000-01-01

The assessment of the flood risk was the objective of the internal flooding analysis for NPPs Bohunice V1, V2 and Mochovce. All important flooding sources were identified. The rooms containing safety important components were analyzed from the point of view of: Integrity of flood boundaries; Capability for drainage; Flood signalisation; Flood localization and liquidation; Vulnerability of safety system component. The redundancies of safety systems are located mostly separately and no flood can endanger more than single train. It can be concluded that NPPs with WWER-440 are very safe against the flooding initiating event

A new flooding scheme by horizontal well in thin heavy oil reservoirs

Energy Technology Data Exchange (ETDEWEB)

Liu, H.; Zhang, H.; Wang, M. [China Univ. of Petroleum, Beijing (China). MOE Key Laboratory of Petroleum Engineering ; Wang, Z. [Shengli Oil Field Co. (China). Dept. of Science and Technology]|[SINOPEC, Shengli (China)

2008-10-15

This paper presented a new flooding scheme for single horizontal wells that could improve recovery from thin marginal heavy oil reservoirs or from offshore reservoirs. The scheme involved the use of a multiple tubing string completion in a single wellbore. Special packers were installed within the long completion horizontal interval to establish an injection zone and a production zone. The new flooding scheme also involved simultaneous injection and production. Numerical simulation of the reservoir was used to determine the thickness of the formation and the lower limitation for different viscosities and the optimum time to start steam flooding after steam soaking by economic oil/steam ratio. The peak recovery efficiency of steam flooding was shown to occur when the length of separation section ratio is 0.15 to 0.2. It was concluded that high thermal efficiency in horizontal wells with long completion intervals can be maintained by alternating between steam soaking and steam flooding. Suitable alternation time to steam flooding is a seventh cycle for horizontal wells. Water cut and pressure difference will increase the steam injection rate, and thereby improve the oil production rate. The suitable injection rate for steam flooding is 2.4 t/d.ha.h because of its slow pressure change. 11 refs., 7 figs.

Characterization of DNAPL Source Zone Architecture and Prediction of Associated Plume Response: Progress and Perspectives

Science.gov (United States)

Abriola, L. M.; Pennell, K. D.; Ramsburg, C. A.; Miller, E. L.; Christ, J.; Capiro, N. L.; Mendoza-Sanchez, I.; Boroumand, A.; Ervin, R. E.; Walker, D. I.; Zhang, H.

2012-12-01

It is now widely recognized that the distribution of contaminant mass will control both the evolution of aqueous phase plumes and the effectiveness of many source zone remediation technologies at sites contaminated by dense nonaqueous phase liquids (DNAPLs). Advances in the management of sites containing DNAPL source zones, however, are currently hampered by the difficulty associated with characterizing subsurface DNAPL 'architecture'. This presentation provides an overview of recent research, integrating experimental and mathematical modeling studies, designed to improve our ability to characterize DNAPL distributions and predict associated plume response. Here emphasis is placed on estimation of the most information-rich DNAPL architecture metrics, through a combination of localized in situ tests and more readily available plume transect concentration observations. Estimated metrics will then serve as inputs to an upscaled screening model for prediction of long term plume response. Machine learning techniques were developed and refined to identify a variety of source zone metrics and associated confidence intervals through the processing of down gradient concentration data. Estimated metrics include the volumes and volume percentages of DNAPL in pools and ganglia, as well as their ratio (pool fraction). Multiphase flow and transport simulations provided training data for model development and assessment that are representative of field-scale DNAPL source zones and their evolving plumes. Here, a variety of release and site heterogeneity (sequential Gaussian permeability) conditions were investigated. Push-pull tracer tests were also explored as a means to provide localized in situ observations to refine these metric estimates. Here, two-dimensional aquifer cell experiments and mathematical modeling were used to quantify upscaled interphase mass transfer rates and the interplay between injection and extraction rates, local source zone architecture, and tracer

Flooding and Flood Management

Science.gov (United States)

Brooks, K.N.; Fallon, J.D.; Lorenz, D.L.; Stark, J.R.; Menard, Jason; Easter, K.W.; Perry, Jim

2011-01-01

Floods result in great human disasters globally and nationally, causing an average of $4 billion of damages each year in the United States. Minnesota has its share of floods and flood damages, and the state has awarded nearly $278 million to local units of government for flood mitigation projects through its Flood Hazard Mitigation Grant Program. Since 1995, flood mitigation in the Red River Valley has exceeded $146 million. Considerable local and state funding has been provided to manage and mitigate problems of excess stormwater in urban areas, flooding of farmlands, and flood damages at road crossings. The cumulative costs involved with floods and flood mitigation in Minnesota are not known precisely, but it is safe to conclude that flood mitigation is a costly business. This chapter begins with a description of floods in Minneosta to provide examples and contrasts across the state. Background material is presented to provide a basic understanding of floods and flood processes, predication, and management and mitigation. Methods of analyzing and characterizing floods are presented because they affect how we respond to flooding and can influence relevant practices. The understanding and perceptions of floods and flooding commonly differ among those who work in flood forecasting, flood protection, or water resource mamnagement and citizens and businesses affected by floods. These differences can become magnified following a major flood, pointing to the need for better understanding of flooding as well as common language to describe flood risks and the uncertainty associated with determining such risks. Expectations of accurate and timely flood forecasts and our ability to control floods do not always match reality. Striving for clarity is important in formulating policies that can help avoid recurring flood damages and costs.

Fresnel zone plate imaging of a 252Cf spontaneous fission source

International Nuclear Information System (INIS)

Stalker, K.T.; Hessel, K.R.

1976-11-01

The feasibility of coded aperture imaging for nuclear fuel motion monitoring is shown using Cf 252 spontaneous fission source. The theory of coded aperture imaging for Fresnel zone plate apertures is presented and design considerations for zone plate construction are discussed. Actual images are obtained which demonstrate a transverse resolution of 1.7 mm and a tomographic resolution of 1.5 millimeters. The capability of obtaining images through 12.7 mm of stainless steel is also shown

The necessity of flood risk maps on Timis River

International Nuclear Information System (INIS)

Aldescu, Geogr Catalin

2008-01-01

The paper aims to clarify the necessity of risk reduction in flood prone areas along the Timis River. Different methods to reduce risk in flood prone areas are analyzed as well. According to the EU Flood Directive it is mandatory for the European countries to develop flood maps and flood risk maps. The maps help to assess the vulnerable zones in the floodable (i.e. flood prone) areas. Many European countries have produced maps which identify areas prone to flooding events for specific known return periods. In Romania the flood risk maps have not been yet produced, but the process has been started to be implemented at the national and regional level, therefore the first results will be soon available. Banat Hydrographical Area was affected by severe floods on Timis River in 2000, 2005 and 2006. The 2005 flood was the most devastating one with large economic losses. As a result of these catastrophes the need for generating flood risk maps along the Timis. River was clearly stated. The water management experts can use these maps in order to identify the 'hot spots' in Timis catchment, give the people a better understanding of flood risk issues and help reducing flood risk more efficient in the identified vulnerable areas.

Tsunami hazard assessment in El Salvador, Central America, from seismic sources through flooding numerical models.

Science.gov (United States)

Álvarez-Gómez, J. A.; Aniel-Quiroga, Í.; Gutiérrez-Gutiérrez, O. Q.; Larreynaga, J.; González, M.; Castro, M.; Gavidia, F.; Aguirre-Ayerbe, I.; González-Riancho, P.; Carreño, E.

2013-11-01

El Salvador is the smallest and most densely populated country in Central America; its coast has an approximate length of 320 km, 29 municipalities and more than 700 000 inhabitants. In El Salvador there were 15 recorded tsunamis between 1859 and 2012, 3 of them causing damages and resulting in hundreds of victims. Hazard assessment is commonly based on propagation numerical models for earthquake-generated tsunamis and can be approached through both probabilistic and deterministic methods. A deterministic approximation has been applied in this study as it provides essential information for coastal planning and management. The objective of the research was twofold: on the one hand the characterization of the threat over the entire coast of El Salvador, and on the other the computation of flooding maps for the three main localities of the Salvadorian coast. For the latter we developed high-resolution flooding models. For the former, due to the extension of the coastal area, we computed maximum elevation maps, and from the elevation in the near shore we computed an estimation of the run-up and the flooded area using empirical relations. We have considered local sources located in the Middle America Trench, characterized seismotectonically, and distant sources in the rest of Pacific Basin, using historical and recent earthquakes and tsunamis. We used a hybrid finite differences-finite volumes numerical model in this work, based on the linear and non-linear shallow water equations, to simulate a total of 24 earthquake-generated tsunami scenarios. Our results show that at the western Salvadorian coast, run-up values higher than 5 m are common, while in the eastern area, approximately from La Libertad to the Gulf of Fonseca, the run-up values are lower. The more exposed areas to flooding are the lowlands in the Lempa River delta and the Barra de Santiago Western Plains. The results of the empirical approximation used for the whole country are similar to the results

Quantifying Uncertainty in Flood Inundation Mapping Using Streamflow Ensembles and Multiple Hydraulic Modeling Techniques

Science.gov (United States)

Hosseiny, S. M. H.; Zarzar, C.; Gomez, M.; Siddique, R.; Smith, V.; Mejia, A.; Demir, I.

2016-12-01

The National Water Model (NWM) provides a platform for operationalize nationwide flood inundation forecasting and mapping. The ability to model flood inundation on a national scale will provide invaluable information to decision makers and local emergency officials. Often, forecast products use deterministic model output to provide a visual representation of a single inundation scenario, which is subject to uncertainty from various sources. While this provides a straightforward representation of the potential inundation, the inherent uncertainty associated with the model output should be considered to optimize this tool for decision making support. The goal of this study is to produce ensembles of future flood inundation conditions (i.e. extent, depth, and velocity) to spatially quantify and visually assess uncertainties associated with the predicted flood inundation maps. The setting for this study is located in a highly urbanized watershed along the Darby Creek in Pennsylvania. A forecasting framework coupling the NWM with multiple hydraulic models was developed to produce a suite ensembles of future flood inundation predictions. Time lagged ensembles from the NWM short range forecasts were used to account for uncertainty associated with the hydrologic forecasts. The forecasts from the NWM were input to iRIC and HEC-RAS two-dimensional software packages, from which water extent, depth, and flow velocity were output. Quantifying the agreement between output ensembles for each forecast grid provided the uncertainty metrics for predicted flood water inundation extent, depth, and flow velocity. For visualization, a series of flood maps that display flood extent, water depth, and flow velocity along with the underlying uncertainty associated with each of the forecasted variables were produced. The results from this study demonstrate the potential to incorporate and visualize model uncertainties in flood inundation maps in order to identify the high flood risk zones.

Assessing the environmental justice consequences of flood risk: a case study in Miami, Florida

Science.gov (United States)

Montgomery, Marilyn C.; Chakraborty, Jayajit

2015-09-01

Recent environmental justice (EJ) research has emphasized the need to analyze social inequities in the distribution of natural hazards such as hurricanes and floods, and examine intra-ethnic diversity in patterns of EJ. This study contributes to the emerging EJ scholarship on exposure to flooding and ethnic heterogeneity by analyzing the racial/ethnic and socioeconomic characteristics of the population residing within coastal and inland flood risk zones in the Miami Metropolitan Statistical Area (MSA), Florida—one of the most ethnically diverse MSAs in the U.S. and one of the most hurricane-prone areas in the world. We examine coastal and inland flood zones separately because of differences in amenities such as water views and beach access. Instead of treating the Hispanic population as a homogenous group, we disaggregate the Hispanic category into relevant country-of-origin subgroups. Inequities in flood risk exposure are statistically analyzed using socio-demographic variables derived from the 2010 U.S. Census and 2007-2011 American Community Survey estimates, and 100-year flood risk zones from the Federal Emergency Management Agency (FEMA). Social vulnerability is represented with two neighborhood deprivation indices called economic insecurity and instability. We also analyze the presence of seasonal/vacation homes and proximity to public beach access sites as water-related amenity variables. Logistic regression modeling is utilized to estimate the odds of neighborhood-level exposure to coastal and inland 100-year flood risks. Results indicate that neighborhoods with greater percentages of non-Hispanic Blacks, Hispanics, and Hispanic subgroups of Colombians and Puerto Ricans are exposed to inland flood risks in areas without water-related amenities, while Mexicans are inequitably exposed to coastal flood risks. Our findings demonstrate the importance of treating coastal and inland flood risks separately while controlling for water-related amenities, and

Investigating extreme flood response to Holocene palaeoclimate in the Chinese monsoonal zone: A palaeoflood case study from the Hanjiang River

Science.gov (United States)

Guo, Yongqiang; Huang, Chun Chang; Pang, Jiangli; Zha, Xiaochun; Zhou, Yali; Wang, Longsheng; Zhang, Yuzhu; Hu, Guiming

2015-06-01

Palaeoflood events recorded by slackwater deposits (SWDs) were investigated extensively by sedimentological criteria of palaeohydrology along the upper Hanjiang River valley. Modern flood SWDs were collected for comparison with palaeoflood SWD in the same reaches. Three typical palaeoflood SWDs were observed within Holocene loess-soil blanket on the first river terrace land. The grain size distributions of palaeoflood SWDs are similar to modern flood SWDs, whereas they are different from eolian loess and soil. Palaeoflood SWD lies in three major pedo-stratigraphic boundaries (TS/L0, L0/S0, and S0/Lt) in the Holocene loess-soil profiles. The chronology of three palaeoflood episodes was established by OSL dating and pedo-stratigraphic correlation with the well-dated Holocene loess-soil profiles in the upper Hanjiang River basin. Holocene palaeoflood events were dated to 9500-8500, 3200-2800, and 1800-1700 a B.P., respectively. Palaeoflood discharges were estimated by the palaeoflood model (i.e., slope-area method and step-backwater method). The highest discharges are 51,680-53,950 m3 s- 1 at the 11,500-time scale in the Xunyang reach of the upper Hanjiang River valley. Holocene extraordinary hydroclimatic events in the Hanjiang River often result from abnormal atmospheric circulations from Southwest monsoons in the Chinese monsoonal zone. These results provide a regional expression of extreme flood response to Holocene palaeoclimate to understand the effects of global climatic variations on the river system dynamics.

Anti-transpirant activity in xylem sap from flooded tomato (Lycopersicon esculentum Mill.) plants is not due to pH-mediated redistributions of root- or shoot-sourced ABA.

Science.gov (United States)

Else, Mark A; Taylor, June M; Atkinson, Christopher J

2006-01-01

In flooded soils, the rapid effects of decreasing oxygen availability on root metabolic activity are likely to generate many potential chemical signals that may impact on stomatal apertures. Detached leaf transpiration tests showed that filtered xylem sap, collected at realistic flow rates from plants flooded for 2 h and 4 h, contained one or more factors that reduced stomatal apertures. The closure could not be attributed to increased root output of the glucose ester of abscisic acid (ABA-GE), since concentrations and deliveries of ABA conjugates were unaffected by soil flooding. Although xylem sap collected from the shoot base of detopped flooded plants became more alkaline within 2 h of flooding, this rapid pH change of 0.5 units did not alter partitioning of root-sourced ABA sufficiently to prompt a transient increase in xylem ABA delivery. More shoot-sourced ABA was detected in the xylem when excised petiole sections were perfused with pH 7 buffer, compared with pH 6 buffer. Sap collected from the fifth oldest leaf of "intact" well-drained plants and plants flooded for 3 h was more alkaline, by approximately 0.4 pH units, than sap collected from the shoot base. Accordingly, xylem [ABA] was increased 2-fold in sap collected from the fifth oldest petiole compared with the shoot base of flooded plants. However, water loss from transpiring, detached leaves was not reduced when the pH of the feeding solution containing 3-h-flooded [ABA] was increased from 6.7 to 7.1 Thus, the extent of the pH-mediated, shoot-sourced ABA redistribution was not sufficient to raise xylem [ABA] to physiologically active levels. Using a detached epidermis bioassay, significant non-ABA anti-transpirant activity was also detected in xylem sap collected at intervals during the first 24 h of soil flooding.

How useful are Swiss flood insurance data for flood vulnerability assessments?

Science.gov (United States)

Röthlisberger, Veronika; Bernet, Daniel; Zischg, Andreas; Keiler, Margreth

2015-04-01

The databases of Swiss flood insurance companies build a valuable but to date rarely used source of information on physical flood vulnerability. Detailed insights into the Swiss flood insurance system are crucial for using the full potential of the different databases for research on flood vulnerability. Insurance against floods in Switzerland is a federal system, the modalities are manly regulated on cantonal level. However there are some common principles that apply throughout Switzerland. First of all coverage against floods (and other particular natural hazards) is an integral part of every fire insurance policy for buildings or contents. This coupling of insurance as well as the statutory obligation to insure buildings in most of the cantons and movables in some of the cantons lead to a very high penetration. Second, in case of damage, the reinstatement costs (value as new) are compensated and third there are no (or little) deductible and co-pay. High penetration and the fact that the compensations represent a large share of the direct, tangible losses of the individual policy holders make the databases of the flood insurance companies a comprehensive and therefore valuable data source for flood vulnerability research. Insurance companies not only store electronically data about losses (typically date, amount of claims payment, cause of damage, identity of the insured object or policyholder) but also about insured objects. For insured objects the (insured) value and the details on the policy and its holder are the main feature to record. On buildings the insurance companies usually computerize additional information such as location, volume, year of construction or purpose of use. For the 19 (of total 26) cantons with a cantonal monopoly insurer the data of these insurance establishments have the additional value to represent (almost) the entire building stock of the respective canton. Spatial referenced insurance data can be used for many aspects of

Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Analysis of core damage frequency from internally induced flooding events for Plant Operational State 5 during a refueling outage. Volume 4

International Nuclear Information System (INIS)

Dandini, V.; Staple, B.; Kirk, H.; Whitehead, D.; Forester, J.

1994-07-01

An estimate of the contribution of internal flooding to the mean core damage frequency at the Grand Gulf Nuclear Station was calculated for Plant Operational State 5 during a refueling outage. Pursuant to this objective, flood zones and sources were identified and flood volumes were calculated. Equipment necessary for the maintenance of plant safety was identified and its vulnerability to flooding was determined. Event trees and fault trees were modified or developed as required, and PRA quantification was performed using the IRRAS code. The mean core damage frequency estimate for GGNS during POS 5 was found to be 2.3 E-8 per year

Case Studies of the ROZ CO₂ Flood and the Combined ROZ/MPZ CO₂ Flood at the Goldsmith Landreth Unit, Ector County, Texas. Using ''Next Generation'' CO₂ EOR Technologies to Optimize the Residual Oil Zone CO₂ Flood

Energy Technology Data Exchange (ETDEWEB)

Trentham, Robert C. [Univ. of Texas, Midland, TX (United States); Melzer, L. Stephen [Univ. of Texas, Midland, TX (United States); Kuuskraa, Vello [Advanced Resources International, Inc., Arlington, VA (United States); Koperna, George [Advanced Resources International, Inc., Arlington, VA (United States)

2015-06-30

The technology for CO₂ Enhanced Oil Recovery (CO₂ EOR) has significantly advanced since the earliest floods were implemented in the 1970s. At least for the Permian Basin region of the U.S., the oil recovery has been now been extended into residual oil zones (ROZs) where the mobile fluid phase is water and immobile phase is oil. But the nature of the formation and fluids within the ROZs has brought some challenges that were not present when flooding the MPZs. The Goldsmith-Landreth project in the Permian Basin was intended to first identify the most pressing issues of the ROZs floods and, secondly, begin to address them with new techniques designed to optimize a flood that commingled the MPZ and the ROZ. The early phase of the research conducted considerable reservoir and fluid characterization work and identified both technical and commercial challenges of producing the enormous quantities of water when flooding the ROZs. It also noted the differing water compositions in the ROZ as compared to the overlying MPZs. A new CO₂ gas lift system using a capillary string was successfully applied during the project which conveyed the CO₂ to the deeper and differing ROZ reservoir conditions at Goldsmith and added a second capillary string that facilitated applying scale inhibitors to mitigate the scaling tendencies of the mixing ROZ and MPZ formation waters. The project also undertook a reservoir modeling effort, using the acquired reservoir characterization data, to history match both the primary and water flood phases of the MPZ and to establish the initial conditions for a modeling effort to forecast response of the ROZ to CO₂ EOR. With the advantage of many profile logs acquired from the operator, some concentration on the original pattern area for the ROZ pilot was accomplished to attempt to perfect the history match for that area. Several optional scenarios for producing the ROZ were simulated seeking to find the

Bayesian flood forecasting methods: A review

Science.gov (United States)

Han, Shasha; Coulibaly, Paulin

2017-08-01

Over the past few decades, floods have been seen as one of the most common and largely distributed natural disasters in the world. If floods could be accurately forecasted in advance, then their negative impacts could be greatly minimized. It is widely recognized that quantification and reduction of uncertainty associated with the hydrologic forecast is of great importance for flood estimation and rational decision making. Bayesian forecasting system (BFS) offers an ideal theoretic framework for uncertainty quantification that can be developed for probabilistic flood forecasting via any deterministic hydrologic model. It provides suitable theoretical structure, empirically validated models and reasonable analytic-numerical computation method, and can be developed into various Bayesian forecasting approaches. This paper presents a comprehensive review on Bayesian forecasting approaches applied in flood forecasting from 1999 till now. The review starts with an overview of fundamentals of BFS and recent advances in BFS, followed with BFS application in river stage forecasting and real-time flood forecasting, then move to a critical analysis by evaluating advantages and limitations of Bayesian forecasting methods and other predictive uncertainty assessment approaches in flood forecasting, and finally discusses the future research direction in Bayesian flood forecasting. Results show that the Bayesian flood forecasting approach is an effective and advanced way for flood estimation, it considers all sources of uncertainties and produces a predictive distribution of the river stage, river discharge or runoff, thus gives more accurate and reliable flood forecasts. Some emerging Bayesian forecasting methods (e.g. ensemble Bayesian forecasting system, Bayesian multi-model combination) were shown to overcome limitations of single model or fixed model weight and effectively reduce predictive uncertainty. In recent years, various Bayesian flood forecasting approaches have been

Modeling the influence of coupled mass transfer processes on mass flux downgradient of heterogeneous DNAPL source zones.

Science.gov (United States)

Yang, Lurong; Wang, Xinyu; Mendoza-Sanchez, Itza; Abriola, Linda M

2018-04-01

Sequestered mass in low permeability zones has been increasingly recognized as an important source of organic chemical contamination that acts to sustain downgradient plume concentrations above regulated levels. However, few modeling studies have investigated the influence of this sequestered mass and associated (coupled) mass transfer processes on plume persistence in complex dense nonaqueous phase liquid (DNAPL) source zones. This paper employs a multiphase flow and transport simulator (a modified version of the modular transport simulator MT3DMS) to explore the two- and three-dimensional evolution of source zone mass distribution and near-source plume persistence for two ensembles of highly heterogeneous DNAPL source zone realizations. Simulations reveal the strong influence of subsurface heterogeneity on the complexity of DNAPL and sequestered (immobile/sorbed) mass distribution. Small zones of entrapped DNAPL are shown to serve as a persistent source of low concentration plumes, difficult to distinguish from other (sorbed and immobile dissolved) sequestered mass sources. Results suggest that the presence of DNAPL tends to control plume longevity in the near-source area; for the examined scenarios, a substantial fraction (43.3-99.2%) of plume life was sustained by DNAPL dissolution processes. The presence of sorptive media and the extent of sorption non-ideality are shown to greatly affect predictions of near-source plume persistence following DNAPL depletion, with plume persistence varying one to two orders of magnitude with the selected sorption model. Results demonstrate the importance of sorption-controlled back diffusion from low permeability zones and reveal the importance of selecting the appropriate sorption model for accurate prediction of plume longevity. Large discrepancies for both DNAPL depletion time and plume longevity were observed between 2-D and 3-D model simulations. Differences between 2- and 3-D predictions increased in the presence of

Modeling the influence of coupled mass transfer processes on mass flux downgradient of heterogeneous DNAPL source zones

Science.gov (United States)

Yang, Lurong; Wang, Xinyu; Mendoza-Sanchez, Itza; Abriola, Linda M.

2018-04-01

Sequestered mass in low permeability zones has been increasingly recognized as an important source of organic chemical contamination that acts to sustain downgradient plume concentrations above regulated levels. However, few modeling studies have investigated the influence of this sequestered mass and associated (coupled) mass transfer processes on plume persistence in complex dense nonaqueous phase liquid (DNAPL) source zones. This paper employs a multiphase flow and transport simulator (a modified version of the modular transport simulator MT3DMS) to explore the two- and three-dimensional evolution of source zone mass distribution and near-source plume persistence for two ensembles of highly heterogeneous DNAPL source zone realizations. Simulations reveal the strong influence of subsurface heterogeneity on the complexity of DNAPL and sequestered (immobile/sorbed) mass distribution. Small zones of entrapped DNAPL are shown to serve as a persistent source of low concentration plumes, difficult to distinguish from other (sorbed and immobile dissolved) sequestered mass sources. Results suggest that the presence of DNAPL tends to control plume longevity in the near-source area; for the examined scenarios, a substantial fraction (43.3-99.2%) of plume life was sustained by DNAPL dissolution processes. The presence of sorptive media and the extent of sorption non-ideality are shown to greatly affect predictions of near-source plume persistence following DNAPL depletion, with plume persistence varying one to two orders of magnitude with the selected sorption model. Results demonstrate the importance of sorption-controlled back diffusion from low permeability zones and reveal the importance of selecting the appropriate sorption model for accurate prediction of plume longevity. Large discrepancies for both DNAPL depletion time and plume longevity were observed between 2-D and 3-D model simulations. Differences between 2- and 3-D predictions increased in the presence of

Modeling Flood Insurance Penetration in the European Non-Life Market: An Overview

Science.gov (United States)

Mohan, P.; Thomson, M.-K.; Das, A.

2012-04-01

Non-life property insurance plays a significant role in assessing and managing economic risk. Understanding the exposure, or property at risk, helps insurers and reinsurers to better categorize and manage their portfolios. However, the nature of the flood peril, in particular adverse selection, has led to a complex system of different insurance covers and policies across Europe owing to its public and private distinctions based on premiums provided as ex ante or ex post, socio-economic characterization and various compensation schemes. To model this significant level of complexity within the European flood insurance market requires not only extensive data research, close understanding of insurance companies and associations as well as historic flood events, but also careful evaluation of the flood hazard in terms of return periods and flood extents, and the economic/ financial background of the geographies involved. This abstract explores different approaches for modeling the flood insurance penetration rates in Europe depending on the information available and complexity involved. For countries which have either a regulated market with mandatory or high penetration rate, as for example found in the UK, France and Switzerland, or indeed countries with negligible insurance cover such as Luxembourg, assumptions about the penetration rates can be made at country level. However, in countries with a private insurance market, the picture becomes inherently more complex. For example in both Austria and Germany, flood insurance is generally restricted, associated with high costs to the insured or not available at all in high risk areas. In order to better manage flood risk, the Austria and German government agencies produced the risk classification systems HORA and ZÜRS, respectively, which categorize risk into four risk zones based on the exceedance probability of a flood occurrence. Except for regions that have preserved mandatory flood inclusion from past policies

Flood risk assessment and mapping for the Lebanese watersheds

Science.gov (United States)

Abdallah, Chadi; Hdeib, Rouya

2016-04-01

Of all natural disasters, floods affect the greatest number of people worldwide and have the greatest potential to cause damage. Nowadays, with the emerging global warming phenomenon, this number is expected to increase. The Eastern Mediterranean area, including Lebanon (10452 Km2, 4.5 M habitant), has witnessed in the past few decades an increase frequency of flooding events. This study profoundly assess the flood risk over Lebanon covering all the 17 major watersheds and a number of small sub-catchments. It evaluate the physical direct tangible damages caused by floods. The risk assessment and evaluation process was carried out over three stages; i) Evaluating Assets at Risk, where the areas and assets vulnerable to flooding are identified, ii) Vulnerability Assessment, where the causes of vulnerability are assessed and the value of the assets are provided, iii) Risk Assessment, where damage functions are established and the consequent damages of flooding are estimated. A detailed Land CoverUse map was prepared at a scale of 1/ 1 000 using 0.4 m resolution satellite images within the flood hazard zones. The detailed field verification enabled to allocate and characterize all elements at risk, identify hotspots, interview local witnesses, and to correlate and calibrate previous flood damages with the utilized models. All filed gathered information was collected through Mobile Application and transformed to be standardized and classified under GIS environment. Consequently; the general damage evaluation and risk maps at different flood recurrence periods (10, 50, 100 years) were established. Major results showed that floods in a winter season (December, January, and February) of 10 year recurrence and of water retention ranging from 1 to 3 days can cause total damages (losses) that reach 1.14 M for crop lands and 2.30 M for green houses. Whereas, it may cause 0.2 M to losses in fruit trees for a flood retention ranging from 3 to 5 days. These numbers differs

Validation of a Global Hydrodynamic Flood Inundation Model

Science.gov (United States)

Bates, P. D.; Smith, A.; Sampson, C. C.; Alfieri, L.; Neal, J. C.

2014-12-01

In this work we present first validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model (LISFLOOD-FP) to simulate flood inundation at 1km resolution globally and then use downscaling algorithms to determine flood extent and depth at 90m spatial resolution. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. We compare these predictions to flood hazard maps developed by national government agencies in the UK and Germany using similar methods but employing detailed local data, and to observed flood extent at a number of sites including St. Louis, USA and Bangkok in Thailand. Results show that global flood hazard models can have considerable skill given careful treatment to overcome errors in the publicly available data that are used as their input.

Flood susceptibility analysis through remote sensing, GIS and frequency ratio model

Science.gov (United States)

Samanta, Sailesh; Pal, Dilip Kumar; Palsamanta, Babita

2018-05-01

Papua New Guinea (PNG) is saddled with frequent natural disasters like earthquake, volcanic eruption, landslide, drought, flood etc. Flood, as a hydrological disaster to humankind's niche brings about a powerful and often sudden, pernicious change in the surface distribution of water on land, while the benevolence of flood manifests in restoring the health of the thalweg from excessive siltation by redistributing the fertile sediments on the riverine floodplains. In respect to social, economic and environmental perspective, flood is one of the most devastating disasters in PNG. This research was conducted to investigate the usefulness of remote sensing, geographic information system and the frequency ratio (FR) for flood susceptibility mapping. FR model was used to handle different independent variables via weighted-based bivariate probability values to generate a plausible flood susceptibility map. This study was conducted in the Markham riverine precinct under Morobe province in PNG. A historical flood inventory database of PNG resource information system (PNGRIS) was used to generate 143 flood locations based on "create fishnet" analysis. 100 (70%) flood sample locations were selected randomly for model building. Ten independent variables, namely land use/land cover, elevation, slope, topographic wetness index, surface runoff, landform, lithology, distance from the main river, soil texture and soil drainage were used into the FR model for flood vulnerability analysis. Finally, the database was developed for areas vulnerable to flood. The result demonstrated a span of FR values ranging from 2.66 (least flood prone) to 19.02 (most flood prone) for the study area. The developed database was reclassified into five (5) flood vulnerability zones segmenting on the FR values, namely very low (less that 5.0), low (5.0-7.5), moderate (7.5-10.0), high (10.0-12.5) and very high susceptibility (more than 12.5). The result indicated that about 19.4% land area as `very high

Coupling Analysis of Heat Island Effects, Vegetation Coverage and Urban Flood in Wuhan

Science.gov (United States)

Liu, Y.; Liu, Q.; Fan, W.; Wang, G.

2018-04-01

In this paper, satellite image, remote sensing technique and geographic information system technique are main technical bases. Spectral and other factors comprehensive analysis and visual interpretation are main methods. We use GF-1 and Landsat8 remote sensing satellite image of Wuhan as data source, and from which we extract vegetation distribution, urban heat island relative intensity distribution map and urban flood submergence range. Based on the extracted information, through spatial analysis and regression analysis, we find correlations among heat island effect, vegetation coverage and urban flood. The results show that there is a high degree of overlap between of urban heat island and urban flood. The area of urban heat island has buildings with little vegetation cover, which may be one of the reasons for the local heavy rainstorms. Furthermore, the urban heat island has a negative correlation with vegetation coverage, and the heat island effect can be alleviated by the vegetation to a certain extent. So it is easy to understand that the new industrial zones and commercial areas which under constructions distribute in the city, these land surfaces becoming bare or have low vegetation coverage, can form new heat islands easily.

Obsidian sources of the Coromandel Volcanic Zone, nortthern New Zealand

International Nuclear Information System (INIS)

Moore, P.R.

2013-01-01

The Coromandel Volcanic Zone includes nine geographically discrete obsidian sources (Fanal, Awana, Te Ahumata, Cooks Beach, Hahei, Tairua, Whangamata, Maratoto and Waihi). Each has a distinctive chemical composition, and some can also be differentiated on the basis of visual characteristics of the obsidian. Chemically, the three northern sources (Fanal, Awana, Te Ahumata), constituting the 'Great Barrier Group', are distinguished by high Rb concentrations and a high Rb/Sr ratio. Obsidian from six of the sources is known to have been utilized by pre-European Maori for the manufacture of flake tools, but at present there is no evidence for exploitation of the Awana, Maratoto and Tairua deposits. (author). 54 refs., 5 figs., 2 tabs.

Raster-based derivation of a flood runoff susceptibility map using the revised runoff curve number (CN) for the Kuantan watershed, Malaysia

DEFF Research Database (Denmark)

Akbari, Abolghasem; Samah, Azizan Abu; Daryabor, Farshid

2016-01-01

This study aims to develop a methodology for generating a flood runoff susceptibility (FRS) map using a revised curve number (CN) method. The study area is in the Kuantan watershed (KW), Malaysia, which was seriously affected by floods in December 2013 and December 2014. A revised runoff CN map w......, the finding of this research provides a road map for government agencies to effectively implement flood mitigation projects in the study area.......This study aims to develop a methodology for generating a flood runoff susceptibility (FRS) map using a revised curve number (CN) method. The study area is in the Kuantan watershed (KW), Malaysia, which was seriously affected by floods in December 2013 and December 2014. A revised runoff CN map....... Approximately 5% of the study area was identified as a very high-risk zone and 13% as high-risk zone. However, the spatial extent of a high-risk zone in the downstream end and lowland areas of the KW could be considered to be the main cause of flood damage in recent years. From practical point of view...

Flood Response System—A Case Study

OpenAIRE

Yogesh Kumar Singh; Upasana Dutta; T. S. Murugesh Prabhu; I. Prabu; Jitendra Mhatre; Manoj Khare; Sandeep Srivastava; Subasisha Dutta

2017-01-01

Flood Response System (FRS) is a network-enabled solution developed using open-source software. The system has query based flood damage assessment modules with outputs in the form of spatial maps and statistical databases. FRS effectively facilitates the management of post-disaster activities caused due to flood, like displaying spatial maps of area affected, inundated roads, etc., and maintains a steady flow of information at all levels with different access rights depending upon the critica...

Spatial distribution and source apportionment of water pollution in different administrative zones of Wen-Rui-Tang (WRT) river watershed, China.

Science.gov (United States)

Yang, Liping; Mei, Kun; Liu, Xingmei; Wu, Laosheng; Zhang, Minghua; Xu, Jianming; Wang, Fan

2013-08-01

Water quality degradation in river systems has caused great concerns all over the world. Identifying the spatial distribution and sources of water pollutants is the very first step for efficient water quality management. A set of water samples collected bimonthly at 12 monitoring sites in 2009 and 2010 were analyzed to determine the spatial distribution of critical parameters and to apportion the sources of pollutants in Wen-Rui-Tang (WRT) river watershed, near the East China Sea. The 12 monitoring sites were divided into three administrative zones of urban, suburban, and rural zones considering differences in land use and population density. Multivariate statistical methods [one-way analysis of variance, principal component analysis (PCA), and absolute principal component score-multiple linear regression (APCS-MLR) methods] were used to investigate the spatial distribution of water quality and to apportion the pollution sources. Results showed that most water quality parameters had no significant difference between the urban and suburban zones, whereas these two zones showed worse water quality than the rural zone. Based on PCA and APCS-MLR analysis, urban domestic sewage and commercial/service pollution, suburban domestic sewage along with fluorine point source pollution, and agricultural nonpoint source pollution with rural domestic sewage pollution were identified to the main pollution sources in urban, suburban, and rural zones, respectively. Understanding the water pollution characteristics of different administrative zones could put insights into effective water management policy-making especially in the area across various administrative zones.

Rebound of a coal tar creosote plume following partial source zone treatment with permanganate.

Science.gov (United States)

Thomson, N R; Fraser, M J; Lamarche, C; Barker, J F; Forsey, S P

2008-11-14

The long-term management of dissolved plumes originating from a coal tar creosote source is a technical challenge. For some sites stabilization of the source may be the best practical solution to decrease the contaminant mass loading to the plume and associated off-site migration. At the bench-scale, the deposition of manganese oxides, a permanganate reaction byproduct, has been shown to cause pore plugging and the formation of a manganese oxide layer adjacent to the non-aqueous phase liquid creosote which reduces post-treatment mass transfer and hence mass loading from the source. The objective of this study was to investigate the potential of partial permanganate treatment to reduce the ability of a coal tar creosote source zone to generate a multi-component plume at the pilot-scale over both the short-term (weeks to months) and the long-term (years) at a site where there is >10 years of comprehensive synoptic plume baseline data available. A series of preliminary bench-scale experiments were conducted to support this pilot-scale investigation. The results from the bench-scale experiments indicated that if sufficient mass removal of the reactive compounds is achieved then the effective solubility, aqueous concentration and rate of mass removal of the more abundant non-reactive coal tar creosote compounds such as biphenyl and dibenzofuran can be increased. Manganese oxide formation and deposition caused an order-of-magnitude decrease in hydraulic conductivity. Approximately 125 kg of permanganate were delivered into the pilot-scale source zone over 35 days, and based on mass balance estimates 35% reduction for all monitored compounds except for biphenyl, dibenzofuran and fluoranthene 150 days after treatment, which is consistent with the bench-scale experimental results. Pre- and post-treatment soil core data indicated a highly variable and random spatial distribution of mass within the source zone and provided no insight into the mass removed of any of the

Sources of Magmatic Volatiles Discharging from Subduction Zone Volcanoes

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Fischer, T.

2001-05-01

Subduction zones are locations of extensive element transfer from the Earth's mantle to the atmosphere and hydrosphere. This element transfer is significant because it can, in some fashion, instigate melt production in the mantle wedge. Aqueous fluids are thought to be the major agent of element transfer during the subduction zone process. Volatile discharges from passively degassing subduction zone volcanoes should in principle, provide some information on the ultimate source of magmatic volatiles in terms of the mantle, the crust and the subducting slab. The overall flux of volatiles from degassing volcanoes should be balanced by the amount of volatiles released from the mantle wedge, the slab and the crust. Kudryavy Volcano, Kurile Islands, has been passively degassing at 900C fumarole temperatures for at least 40 years. Extensive gas sampling at this basaltic andesite cone and application of CO2/3He, N2/3He systematics in combination with C and N- isotopes indicates that 80% of the CO2 and approximately 60% of the N 2 are contributed from a sedimentary source. The mantle wedge contribution for both volatiles is, with 12% and 17% less significant. Direct volatile flux measurements from the volcano using the COSPEC technique in combination with direct gas sampling allows for the calculation of the 3He flux from the volcano. Since 3He is mainly released from the astenospheric mantle, the amount of mantle supplying the 3He flux can be determined if initial He concentrations of the mantle melts are known. The non-mantle flux of CO2 and N2 can be calculated in similar fashion. The amount of non-mantle CO2 and N2 discharging from Kudryavy is balanced by the amount of CO2 and N2 subducted below Kudryavy assuming a zone of melting constrained by the average spacing of the volcanoes along the Kurile arc. The volatile budget for Kudryavy is balanced because the volatile flux from the volcano is relatively small (75 t/day (416 Mmol/a) SO2, 360 Mmol/a of non-mantle CO2 and

Taxation records as a source of information for the study of historical floods in Southern Moravia, Czech Republic

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Brázdil, Rudolf; Valášek, Hubert; Chromá, Kateřina; Dolák, Lukáš; Řezníčková, Ladislava; Dobrovolný, Petr

2014-05-01

The taxation system in Moravia allowed farmers to request tax relief if their crop yields had been negatively affected by hydrometeorological extremes. Firstly, the owners of land or individual farmers sent basic information about what had taken place, together with a detailed description of the damage, to the state executive (regional offices). After this, commissioners appointed by the regional administrator were obliged to inspect the places affected personally (in situ) and make records. Finally, the state executive made its decision as to whether to allow or reject the tax relief requested. The whole process was reflected in various surviving archival documents which contain information about the type of extreme event and the date of its occurrence, while the impact on crops may often be derived. Taxation documents of 201 estates in Southern Moravia, Czech Republic, prevailingly located in Moravian Land Archives in Brno, were studied to find information about hydrometeorological extremes. Such information is included for 84 of them. These data covering mainly the 18th-19th centuries were used for the study of historical floods (flash floods) complemented by other documentary sources and systematic hydrological observations (water stages, discharges) in the instrumental period (from the 1880s). Obtained flood data are analysed with respect to their temporal (frequency, seasonality) and spatial changes. Finally, uncertainties related to taxation records, such as their temporal and spatial incompleteness, the limits of the period of outside agricultural work (i.e. mainly May-August) and the purpose for which they were originally collected (primarily tax alleviation, i.e. information about hydrometeorological extremes was of secondary importance) are discussed with respect to results obtained. Taxation records constitute an important source of data for the study of historical floods with a great potential to be used in many European countries.

Household adjustment to flood risk: a survey of coastal residents in Texas and Florida, United States.

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Brody, Samuel D; Lee, Yoonjeong; Highfield, Wesley E

2017-07-01

Individual households have increasingly borne responsibility for reducing the adverse impacts of flooding on their property. Little observational research has been conducted, however, at the household level to examine the major factors contributing to the selection of a particular household adjustment. This study addresses the issue by evaluating statistically the factors influencing the adoption of various household flood hazard adjustments. The results indicate that respondents with higher-value homes or longer housing tenure are more likely to adopt structural and expensive techniques. In addition, the information source and the Community Rating System (CRS) score for the jurisdiction where the household is located have a significant bearing on household adjustment. In contrast, proximity to risk zones and risk perception yield somewhat mixed results or behave counter to assumptions in the literature. The study findings provide insights that will be of value to governments and decision-makers interested in encouraging homeowners to take protective action given increasing flood risk. © 2017 The Author(s). Disasters © Overseas Development Institute, 2017.

Three dimensional numerical modeling of flow and pollutant transport in a flooding area of 2008 US Midwest Flood

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This paper presents the development and application of a three-dimensional numerical model for simulating the flow field and pollutant transport in a flood zone near the confluence of the Mississippi River and Iowa River in Oakville, Iowa. Due to a levee breaching along the Iowa River during the US ...

Flood Risk Management in Iowa through an Integrated Flood Information System

Science.gov (United States)

Demir, Ibrahim; Krajewski, Witold

2013-04-01

The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts both short-term and seasonal, flood-related data, information and interactive visualizations for communities in Iowa. The key element of the system's architecture is the notion of community. Locations of the communities, those near streams and rivers, define basin boundaries. The IFIS provides community-centric watershed and river characteristics, weather (rainfall) conditions, and streamflow data and visualization tools. Interactive interfaces allow access to inundation maps for different stage and return period values, and flooding scenarios with contributions from multiple rivers. Real-time and historical data of water levels, gauge heights, and rainfall conditions are available in the IFIS by streaming data from automated IFC bridge sensors, USGS stream gauges, NEXRAD radars, and NWS forecasts. Simple 2D and 3D interactive visualizations in the IFIS make the data more understandable to general public. Users are able to filter data sources for their communities and selected rivers. The data and information on IFIS is also accessible through web services and mobile applications. The IFIS is optimized for various browsers and screen sizes to provide access through multiple platforms including tablets and mobile devices. The IFIS includes a rainfall-runoff forecast model to provide a five-day flood risk estimate for around 1100 communities in Iowa. Multiple view modes in the IFIS accommodate different user types from general public to researchers and decision makers by providing different level of tools and details. River view mode allows users to visualize data from multiple IFC bridge sensors and USGS stream gauges to follow flooding condition along a river. The IFIS will help communities make better-informed decisions on the occurrence of floods, and will alert

Real Time Estimation of the Calgary Floods Using Limited Remote Sensing Data

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Emily Schnebele

2014-02-01

Full Text Available Every year, flood disasters are responsible for widespread destruction and loss of human life. Remote sensing data are capable of providing valuable, synoptic coverage of flood events but are not always available because of satellite revisit limitations, obstructions from cloud cover or vegetation canopy, or expense. In addition, knowledge of road accessibility is imperative during all phases of a flood event. In June 2013, the City of Calgary experienced sudden and extensive flooding but lacked comprehensive remote sensing coverage. Using this event as a case study, this work illustrates how data from non-authoritative sources are used to augment traditional data and methods to estimate flood extent and identify affected roads during a flood disaster. The application of these data, which may have varying resolutions and uncertainities, provide an estimation of flood extent when traditional data and methods are lacking or incomplete. When flooding occurs over multiple days, it is possible to construct an estimate of the advancement and recession of the flood event. Non-authoritative sources also provide flood information at the micro-level, which can be difficult to capture from remote sensing data; however, the distibution and quantity of data collected from these sources will affect the quality of the flood estimations.

Damaging Rainfall and Flooding. The Other Sahel Hazards

Energy Technology Data Exchange (ETDEWEB)

Tarhule, A. [Department of Geography, University of Oklahoma, 100 East Boyd Street, Norman, OK, 73079 (United States)

2005-10-01

Damaging rainfall and rain-induced flooding occur from time to time in the drought-prone Sahel savannah zone of Niger in West Africa but official records of these events and their socioeconomic impacts do not exist. This paper utilized newspaper accounts between 1970 and 2000 to survey and illustrate the range of these flood hazards in the Sahel. During the study interval, 53 newspaper articles reported 79 damaging rainfall and flood events in 47 different communities in the Sahel of Niger. Collectively, these events destroyed 5,580 houses and rendered 27,289 people homeless. Cash losses and damage to infrastructure in only three events exceeded $4 million. Sahel residents attribute these floods to five major causes including both natural and anthropogenic, but they view the flood problem as driven primarily by land use patterns. Despite such awareness, traditional coping strategies appear inadequate for dealing with the problems in part because of significant climatic variability. Analysis of several rainfall measures indicates that the cumulative rainfall in the days prior to a heavy rain event is an important factor influencing whether or not heavy rainfall results in flooding. Thus, despite some limitations, newspaper accounts of historical flooding are largely consistent with measured climatic variables. The study demonstrates that concerted effort is needed to improve the status of knowledge concerning flood impacts and indeed other natural and human hazards in the Sahel.

Bioavailability of radionuclides and dose rate in aquatic ecosystems within the Chernobyl accident exclusion zone

International Nuclear Information System (INIS)

Gudkov, Dmitri; Nazarov, Alexandr

2008-01-01

of plants irradiation has increased more than in 6 times, that testifies to essential deterioration of radiating conditions for aquatic biota, in particular for higher aquatic plants within territory of Krasnensky flood-lands. At the same time there is a formation of the peculiar 'depot' of the mobile forms of radioactive substances, which can be a source of increase of 90 Sr carry-over into the Pripyat River and then - beyond the bounds of the exclusion zone during the high water-level periods. (author)

Floods and Flash Flooding

Science.gov (United States)

Floods and flash flooding Now is the time to determine your area’s flood risk. If you are not sure whether you ... If you are in a floodplain, consider buying flood insurance. Do not drive around barricades. If your ...

Food Vulnerability and Alluvial Farming for Food Security in Central Dry Zone Area of Myanmar

Science.gov (United States)

Boori, M. S.; Choudhary, K.; Evers, M.; Kupriyanov, A.

2017-10-01

The central dry zone area of Myanmar is the most water stressed and also one of the most food insecure regions in the country. In the Dry Zone area, the total population is 10.1 million people in 54 townships, in which approximately 43 % live in below poverty line and 40-50 % of the rural population is landless. Agriculture is the most important economic sector in Myanmar as it is essential for national food security and a major source of livelihood for its people. In this region the adverse effects of climate change such as late or early onset of monsoon season, longer dry spells, erratic rainfall, increasing temperature, heavy rains, stronger typhoons, extreme spatial-temporal variability of rainfall, high intensities, limited rainfall events in the growing season, heat stress, drought, flooding, sea water intrusion, land degradation, desertification, deforestation and other natural disasters are believed to be a major constraint to food insecurity. For food vulnerability, we use following indicators: slope, precipitation, vegetation, soil, erosion, land degradation and harvest failure in ArcGIS software. The erosion is influenced by rainfall and slope, while land degradation is directly related to vegetation, drainage and soil. While harvest failure can be generate by rainfall and flood potential zones. Results show that around 45 % study area comes under very high erosion danger level, 70 % under average harvest failure, 59 % intermediate land degradation area and the overall around 45 % study area comes under insecure food vulnerability zone. Our analysis shows an increase in alluvial farming by 1745.33 km2 since 1988 to reduce the insecure food vulnerability. Food vulnerability map is also relevant to increased population and low income areas. The extreme climatic events are likely increase in frequency and magnitude of serious drought periods and extreme floods. Food insecurity is an important thing that must be reviewed because it relates to

FOOD VULNERABILITY AND ALLUVIAL FARMING FOR FOOD SECURITY IN CENTRAL DRY ZONE AREA OF MYANMAR

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M. S. Boori

2017-10-01

Full Text Available The central dry zone area of Myanmar is the most water stressed and also one of the most food insecure regions in the country. In the Dry Zone area, the total population is 10.1 million people in 54 townships, in which approximately 43 % live in below poverty line and 40–50 % of the rural population is landless. Agriculture is the most important economic sector in Myanmar as it is essential for national food security and a major source of livelihood for its people. In this region the adverse effects of climate change such as late or early onset of monsoon season, longer dry spells, erratic rainfall, increasing temperature, heavy rains, stronger typhoons, extreme spatial-temporal variability of rainfall, high intensities, limited rainfall events in the growing season, heat stress, drought, flooding, sea water intrusion, land degradation, desertification, deforestation and other natural disasters are believed to be a major constraint to food insecurity. For food vulnerability, we use following indicators: slope, precipitation, vegetation, soil, erosion, land degradation and harvest failure in ArcGIS software. The erosion is influenced by rainfall and slope, while land degradation is directly related to vegetation, drainage and soil. While harvest failure can be generate by rainfall and flood potential zones. Results show that around 45 % study area comes under very high erosion danger level, 70 % under average harvest failure, 59 % intermediate land degradation area and the overall around 45 % study area comes under insecure food vulnerability zone. Our analysis shows an increase in alluvial farming by 1745.33 km2 since 1988 to reduce the insecure food vulnerability. Food vulnerability map is also relevant to increased population and low income areas. The extreme climatic events are likely increase in frequency and magnitude of serious drought periods and extreme floods. Food insecurity is an important thing that must be reviewed

Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

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Jakub Langhammer

2017-11-01

Full Text Available This paper explores the potential of the joint application of unmanned aerial vehicle (UAV-based photogrammetry and an automated sensor network for building a hydrodynamic flood model of a montane stream. UAV-based imagery was used for three-dimensional (3D photogrammetric reconstruction of the stream channel, achieving a resolution of 1.5 cm/pixel. Automated ultrasonic water level gauges, operating with a 10 min interval, were used as a source of hydrological data for the model calibration, and the MIKE 21 hydrodynamic model was used for building the flood model. Three different horizontal schematizations of the channel—an orthogonal grid, curvilinear grid, and flexible mesh—were used to evaluate the effect of spatial discretization on the results. The research was performed on Javori Brook, a montane stream in the Sumava (Bohemian Forest Mountains, Czech Republic, Central Europe, featuring a fast runoff response to precipitation events and that is located in a core zone of frequent flooding. The studied catchments have been, since 2007, equipped with automated water level gauges and, since 2013, under repeated UAV monitoring. The study revealed the high potential of these data sources for applications in hydrodynamic modeling. In addition to the ultra-high levels of spatial and temporal resolution, the major contribution is in the method’s high operability, enabling the building of highly detailed flood models even in remote areas lacking conventional monitoring. The testing of the data sources and model setup indicated the limitations of the UAV reconstruction of the stream bathymetry, which was completed by the geodetic-grade global navigation satellite system (GNSS measurements. The testing of the different model domain schematizations did not indicate the substantial differences that are typical for conventional low-resolution data, proving the high reliability of the tested modeling workflow.

Climate Change and Flooding in an Ecologically Fragile Zone of Nigerian Coastal Areas: A Case Study of Ilaje Settlement in Lagos, Nigeria

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Oni, A. F.

2017-12-01

Climate change exacerbates the environmental condition directly or indirectly. The frequency of climate-related disasters worldwide has been on the increase with their amplitude growing. The consequences of climate-related disaster are not limited to loss of lives and properties alone, but also serious repercussions on post-disaster reconstruction, as well as the cost implications for resilience of the infrastructure and natural environment. In developing countries, the low-income group whose income is below the world poverty line is the most vulnerable to the dangers of climate change. To worsen the case, the political and economic strength of these countries in terms of economic resources, technological development and urban planning management necessary for adapting to climate change are relatively weak. This study takes an inventory of the study area environment to establish its environmental state in terms of the extent of its vulnerability and economic strength. It was found that the study area is vulnerable being a coastal area and could be described as a slum settlement. Also, information on frequency and extent of flooding in association with change in temperature was collected. The results show that the frequency of flood occurrence within the period has increased and the increase was attributed to rise in sea level alongside a significant increase in temperature within the period of study. The implications of the findings on loss of lives/properties and continuous decline in the area economic strength as it relates to resilience of the area was discussed. The study suggests an effective urban land use management and control, as well as redevelopment of resilient infrastructure in the area. The study concludes that the increase in temperature for the period as an indicator of climate change causes rise in sea level and the subsequent increase in flooding occurrence. Key Words: Ecologically Fragile Zone, Climate Change, Flooding and Vulnerability.

Open Source and Open Standard based decision support system: the example of lake Verbano floods management.

Science.gov (United States)

Cannata, Massimiliano; Antonovic, Milan; Pozzoni, Maurizio; Graf, Andrea

2015-04-01

The Locarno area (Switzerland, Canton Ticino) is exposed to lacual floods with a return period of about 7-8 years. The risk is of particular concern because the area is located in a floodplain that registered in the last decades a great increase in settlement and values of the real estates. Moreover small differences in lake altitude may produce a significant increase in flooded area due to the very low average slope of the terrain. While fatalities are not generally registered, several important economic costs are associated, e.g.: damages to real estates, interruption of activities, evacuation and relocation and environmental damages. While important events were registered in 1978, 1993, 2000, 2002 and 2014 the local stakeholder invested time and money in the set-up of an up-to-date decision support system that allows for the reduction of risks. Thanks to impressive technological advances the visionary concept of the Digital Earth (Gore 1992, 1998) is being realizing: geospatial coverages and monitoring systems data are increasingly available on the Web, and more importantly, in a standard format. As a result, today is possible to develop innovative decision support systems (Molinari et al. 2013) which mesh-up several information sources and offers special features for risk scenarios evaluation. In agreement with the exposed view, the authors have recently developed a new Web system whose design is based on the Service Oriented Architecture pattern. Open source software (e.g.: Geoserver, PostGIS, OpenLayers) has been used throughout the whole system and geospatial Open Standards (e.g.: SOS, WMS, WFS) are the pillars it rely on. SITGAP 2.0, implemented in collaboration with the Civil protection of Locarno e Vallemaggia, combines a number of data sources such as the Federal Register of Buildings and Dwellings, the Cantonal Register of residents, the Cadastral Surveying, the Cantonal Hydro-meteorological monitoring observations, the Meteoswiss weather forecasts, and

Assessing the joint impact of DNAPL source-zone behavior and degradation products on the probabilistic characterization of human health risk

Science.gov (United States)

Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

2016-02-01

The release of industrial contaminants into the subsurface has led to a rapid degradation of groundwater resources. Contamination caused by Dense Non-Aqueous Phase Liquids (DNAPLs) is particularly severe owing to their limited solubility, slow dissolution and in many cases high toxicity. A greater insight into how the DNAPL source zone behavior and the contaminant release towards the aquifer impact human health risk is crucial for an appropriate risk management. Risk analysis is further complicated by the uncertainty in aquifer properties and contaminant conditions. This study focuses on the impact of the DNAPL release mode on the human health risk propagation along the aquifer under uncertain conditions. Contaminant concentrations released from the source zone are described using a screening approach with a set of parameters representing several scenarios of DNAPL architecture. The uncertainty in the hydraulic properties is systematically accounted for by high-resolution Monte Carlo simulations. We simulate the release and the transport of the chlorinated solvent perchloroethylene and its carcinogenic degradation products in randomly heterogeneous porous media. The human health risk posed by the chemical mixture of these contaminants is characterized by the low-order statistics and the probability density function of common risk metrics. We show that the zone of high risk (hot spot) is independent of the DNAPL mass release mode, and that the risk amplitude is mostly controlled by heterogeneities and by the source zone architecture. The risk is lower and less uncertain when the source zone is formed mostly by ganglia than by pools. We also illustrate how the source zone efficiency (intensity of the water flux crossing the source zone) affects the risk posed by an exposure to the chemical mixture. Results display that high source zone efficiencies are counter-intuitively beneficial, decreasing the risk because of a reduction in the time available for the production

The Global Flood Model

Science.gov (United States)

Williams, P.; Huddelston, M.; Michel, G.; Thompson, S.; Heynert, K.; Pickering, C.; Abbott Donnelly, I.; Fewtrell, T.; Galy, H.; Sperna Weiland, F.; Winsemius, H.; Weerts, A.; Nixon, S.; Davies, P.; Schiferli, D.

2012-04-01

Recently, a Global Flood Model (GFM) initiative has been proposed by Willis, UK Met Office, Esri, Deltares and IBM. The idea is to create a global community platform that enables better understanding of the complexities of flood risk assessment to better support the decisions, education and communication needed to mitigate flood risk. The GFM will provide tools for assessing the risk of floods, for devising mitigation strategies such as land-use changes and infrastructure improvements, and for enabling effective pre- and post-flood event response. The GFM combines humanitarian and commercial motives. It will benefit: - The public, seeking to preserve personal safety and property; - State and local governments, seeking to safeguard economic activity, and improve resilience; - NGOs, similarly seeking to respond proactively to flood events; - The insurance sector, seeking to understand and price flood risk; - Large corporations, seeking to protect global operations and supply chains. The GFM is an integrated and transparent set of modules, each composed of models and data. For each module, there are two core elements: a live "reference version" (a worked example) and a framework of specifications, which will allow development of alternative versions. In the future, users will be able to work with the reference version or substitute their own models and data. If these meet the specification for the relevant module, they will interoperate with the rest of the GFM. Some "crowd-sourced" modules could even be accredited and published to the wider GFM community. Our intent is to build on existing public, private and academic work, improve local adoption, and stimulate the development of multiple - but compatible - alternatives, so strengthening mankind's ability to manage flood impacts. The GFM is being developed and managed by a non-profit organization created for the purpose. The business model will be inspired from open source software (eg Linux): - for non-profit usage

Hydrogeophysical imaging of deposit heterogeneity and groundwater chemistry changes during DNAPL source zone bioremediation.

Science.gov (United States)

Chambers, J E; Wilkinson, P B; Wealthall, G P; Loke, M H; Dearden, R; Wilson, R; Allen, D; Ogilvy, R D

2010-10-21

Robust characterization and monitoring of dense nonaqueous phase liquid (DNAPL) source zones is essential for designing effective remediation strategies, and for assessing the efficacy of treatment. In this study high-resolution cross-hole electrical resistivity tomography (ERT) was evaluated as a means of monitoring a field-scale in-situ bioremediation experiment, in which emulsified vegetable oil (EVO) electron donor was injected into a trichloroethene source zone. Baseline ERT scans delineated the geometry of the interface between the contaminated alluvial aquifer and the underlying mudstone bedrock, and also the extent of drilling-induced physical heterogeneity. Time-lapse ERT images revealed major preferential flow pathways in the source and plume zones, which were corroborated by multiple lines of evidence, including geochemical monitoring and hydraulic testing using high density multilevel sampler arrays within the geophysical imaging planes. These pathways were shown to control the spatial distribution of the injected EVO, and a bicarbonate buffer introduced into the cell for pH control. Resistivity signatures were observed within the preferential flow pathways that were consistent with elevated chloride levels, providing tentative evidence from ERT of the biodegradation of chlorinated solvents. Copyright © 2010 S. Yamamoto. Published by Elsevier B.V. All rights reserved.

HISTORICAL FLOOD RISK MANAGEMENT: SPATIAL EXPANSION OF GHERGHIȚA VILLAGE (LOWER PRAHOVA RIVER

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IOANA-TOROIMAC GABRIELA

2015-03-01

Full Text Available This paper analyses settlements expansion in flood zones during historical time. We focused on the example of Gherghiţa village on Lower Prahova River by using a diachronic study in GIS. It revealed three major periods of extension of Gherghița village and flood risk management: (1 from Middle Age to the end of the 19th century – prevention against floods by expansion outside the flood-prone area; (2 during the major part of the 20th – flood negligence by expansion inside the flood-prone area; (3 at the end of the 20th century and at the beginning of the 21th century – protection against floods by extension inside the flood-prone area with structural measures (i.e. levees. As a consequence, human pressure on Lower Prahova River grew since the beginning of the 20th century, especially for agricultural purposes.

Flood risk on the Black sea coast of Russia

Science.gov (United States)

Alekseevsky, Nikolay; Magritsky, Dmitry; Koltermann, Peter; Krylenko, Inna; Umina, Natalya; Aybulatov, Denis; Efremova, Natalya; Lebedeva, Seraphima

2013-04-01

The data of unique database "Floods in the coastal zones of Europeans part of Russia", developed by authors, are shown, that frequency of floods and damage in the coastal zones are growing. There is most dangerous situation on the Black sea coast of Russia. Here the main part of settlements, resorts and industry is situated in the river valleys and mouths. All main roads and pipelines cross the river channels. The Black sea rivers have flood regime with high intensity of flood formations and huge destructive flood power. Despite prevalence of floods during the cold period of year the most part of high floods in 100 years of supervision was noted here in the summer-fall (65% in July-October). Usually they were induced by the showers connected with passing of powerful cyclones, atmospheric fronts, and water tornadoes. The insignificant part of floods was connected with snow melting, backwater phenomena, showers in the cities and dam breaks. Thus shower induced floods here are the most widespread and destructive. Usually they arise within two-three watersheds simultaneously. Formation catastrophic heavy rain flood is possible on any site of a river valley of the Black Sea coast. The wave of a high water moves with very high speed, carrying a large number of deposits and garbage. To the mouth the flood can be transformed into debris flow. The water levels during a high water period rise on 3-6 m in the channels, and up to 11-12 m in the river canyons; the maximum depths of flow on the floodplains are 3 m and more. Flooding depths, induced by slope streams, can be to 0,5 m and higher. Flooding proceeds only some hours. After that water rather quickly flows down from a floodplains to the bed of the rivers and into the sea, leaving traces of destructions, a powerful layer of deposits (to 10-20 cm and more) and garbage. In the mouth river deposits quite often form the river mouth bar which is washed away during next storms. The damage from river floods on the Black Sea

Detection and assessment of flood susceptible irrigation networks in Licab, Nueva Ecija, Philippines using LiDAR DTM

Science.gov (United States)

Alberto, R. T.; Hernando, P. J. C.; Tagaca, R. C.; Celestino, A. B.; Palado, G. C.; Camaso, E. E.; Damian, G. B.

2017-09-01

Climate change has wide-ranging effects on the environment and socio-economic and related sectors which includes water resources, agriculture and food security, human health, terrestrial ecosystems, coastal zones and biodiversity. Farmers are under pressure to the changing weather and increasing unpredictable water supply. Because of rainfall deficiencies, artificial application of water has been made through irrigation. Irrigation is a basic determinant of agriculture because its inadequacies are the most powerful constraints on the increase of agricultural production. Irrigation networks are permanent and temporary conduits that supply water to agricultural areas from an irrigation source. Detection of irrigation networks using LiDAR DTM, and flood susceptible assessment of irrigation networks could give baseline information on the development and management of sustainable agriculture. Map Gully Depth (MGD) in Whitebox GAT was used to generate the potential irrigation networks. The extracted MGD was overlaid in ArcGIS as guide in the digitization of potential irrigation networks. A flood hazard map was also used to identify the flood susceptible irrigation networks in the study area. The study was assessed through field validation of points which were generated using random sampling method. Results of the study showed that most of the detected irrigation networks have low to moderate susceptibility to flooding while the rest have high susceptibility to flooding which is due to shifting weather. These irrigation networks may cause flood when it overflows that could also bring huge damage to rice and other agricultural areas.

Large Scale Water Vapor Sources Relative to the October 2000 Piedmont Flood

Science.gov (United States)

Turato, Barbara; Reale, Oreste; Siccardi, Franco

2003-01-01

Very intense mesoscale or synoptic-scale rainfall events can occasionally be observed in the Mediterranean region without any deep cyclone developing over the areas affected by precipitation. In these perplexing cases the synoptic situation can superficially look similar to cases in which very little precipitation occurs. These situations could possibly baffle the operational weather forecasters. In this article, the major precipitation event that affected Piedmont (Italy) between 13 and 16 October 2000 is investigated. This is one of the cases in which no intense cyclone was observed within the Mediterranean region at any time, only a moderate system was present, and yet exceptional rainfall and flooding occurred. The emphasis of this study is on the moisture origin and transport. Moisture and energy balances are computed on different space- and time-scales, revealing that precipitation exceeds evaporation over an area inclusive of Piedmont and the northwestern Mediterranean region, on a time-scale encompassing the event and about two weeks preceding it. This is suggestive of an important moisture contribution originating from outside the region. A synoptic and dynamic analysis is then performed to outline the potential mechanisms that could have contributed to the large-scale moisture transport. The central part of the work uses a quasi-isentropic water-vapor back trajectory technique. The moisture sources obtained by this technique are compared with the results of the balances and with the synoptic situation, to unveil possible dynamic mechanisms and physical processes involved. It is found that moisture sources on a variety of atmospheric scales contribute to this event. First, an important contribution is caused by the extratropical remnants of former tropical storm Leslie. The large-scale environment related to this system allows a significant amount of moisture to be carried towards Europe. This happens on a time- scale of about 5-15 days preceding the

Monitoring well utility in a heterogeneous DNAPL source zone area: Insights from proximal multilevel sampler wells and sampling capture-zone modelling.

Science.gov (United States)

McMillan, Lindsay A; Rivett, Michael O; Wealthall, Gary P; Zeeb, Peter; Dumble, Peter

2018-03-01

Groundwater-quality assessment at contaminated sites often involves the use of short-screen (1.5 to 3 m) monitoring wells. However, even over these intervals considerable variation may occur in contaminant concentrations in groundwater adjacent to the well screen. This is especially true in heterogeneous dense non-aqueous phase liquid (DNAPL) source zones, where cm-scale contamination variability may call into question the effectiveness of monitoring wells to deliver representative data. The utility of monitoring wells in such settings is evaluated by reference to high-resolution multilevel sampler (MLS) wells located proximally to short-screen wells, together with sampling capture-zone modelling to explore controls upon well sample provenance and sensitivity to monitoring protocols. Field data are analysed from the highly instrumented SABRE research site that contained an old trichloroethene source zone within a shallow alluvial aquifer at a UK industrial facility. With increased purging, monitoring-well samples tend to a flow-weighted average concentration but may exhibit sensitivity to the implemented protocol and degree of purging. Formation heterogeneity adjacent to the well-screen particularly, alongside pump-intake position and water level, influence this sensitivity. Purging of low volumes is vulnerable to poor reproducibility arising from concentration variability predicted over the initial 1 to 2 screen volumes purged. Marked heterogeneity may also result in limited long-term sample concentration stabilization. Development of bespoke monitoring protocols, that consider screen volumes purged, alongside water-quality indicator parameter stabilization, is recommended to validate and reduce uncertainty when interpreting monitoring-well data within source zone areas. Generalised recommendations on monitoring well based protocols are also developed. A key monitoring well utility is their proportionately greater sample draw from permeable horizons constituting

Monitoring well utility in a heterogeneous DNAPL source zone area: Insights from proximal multilevel sampler wells and sampling capture-zone modelling

Science.gov (United States)

McMillan, Lindsay A.; Rivett, Michael O.; Wealthall, Gary P.; Zeeb, Peter; Dumble, Peter

2018-03-01

Groundwater-quality assessment at contaminated sites often involves the use of short-screen (1.5 to 3 m) monitoring wells. However, even over these intervals considerable variation may occur in contaminant concentrations in groundwater adjacent to the well screen. This is especially true in heterogeneous dense non-aqueous phase liquid (DNAPL) source zones, where cm-scale contamination variability may call into question the effectiveness of monitoring wells to deliver representative data. The utility of monitoring wells in such settings is evaluated by reference to high-resolution multilevel sampler (MLS) wells located proximally to short-screen wells, together with sampling capture-zone modelling to explore controls upon well sample provenance and sensitivity to monitoring protocols. Field data are analysed from the highly instrumented SABRE research site that contained an old trichloroethene source zone within a shallow alluvial aquifer at a UK industrial facility. With increased purging, monitoring-well samples tend to a flow-weighted average concentration but may exhibit sensitivity to the implemented protocol and degree of purging. Formation heterogeneity adjacent to the well-screen particularly, alongside pump-intake position and water level, influence this sensitivity. Purging of low volumes is vulnerable to poor reproducibility arising from concentration variability predicted over the initial 1 to 2 screen volumes purged. Marked heterogeneity may also result in limited long-term sample concentration stabilization. Development of bespoke monitoring protocols, that consider screen volumes purged, alongside water-quality indicator parameter stabilization, is recommended to validate and reduce uncertainty when interpreting monitoring-well data within source zone areas. Generalised recommendations on monitoring well based protocols are also developed. A key monitoring well utility is their proportionately greater sample draw from permeable horizons constituting a

Flood Water Segmentation from Crowdsourced Images

Science.gov (United States)

Nguyen, J. K.; Minsker, B. S.

2017-12-01

In the United States, 176 people were killed by flooding in 2015. Along with the loss of human lives is the economic cost which is estimated to be $4.5 billion per flood event. Urban flooding has become a recent concern due to the increase in population, urbanization, and global warming. As more and more people are moving into towns and cities with infrastructure incapable of coping with floods, there is a need for more scalable solutions for urban flood management.The proliferation of camera-equipped mobile devices have led to a new source of information for flood research. In-situ photographs captured by people provide information at the local level that remotely sensed images fail to capture. Applications of crowdsourced images to flood research required understanding the content of the image without the need for user input. This paper addresses the problem of how to automatically segment a flooded and non-flooded region in crowdsourced images. Previous works require two images taken at similar angle and perspective of the location when it is flooded and when it is not flooded. We examine three different algorithms from the computer vision literature that are able to perform segmentation using a single flood image without these assumptions. The performance of each algorithm is evaluated on a collection of labeled crowdsourced flood images. We show that it is possible to achieve a segmentation accuracy of 80% using just a single image.

Rhizosphere dynamics of two riparian plant species from the water fluctuation zone of Three Gorges Reservoir, P.R. China - pH, oxygen and LMWOA monitoring during short flooding events

Science.gov (United States)

Schreiber, Christina M.; Schurr, Ulrich; Zeng, Bo; Höltkemeier, Agnes; Kuhn, Arnd J.

2010-05-01

Since the construction of the Three Gorges Dam at the Yangtze River in China, the reservoir management created a new 30m water fluctuation zone 45-75m above the original water level. Only species well adapted to long-time flooding (up to several months) will be able to vegetate the river banks and replace the original vegetation. To investigate how common species of the riverbanks cope with submergence, Alternanthera philoxeroides Mart. and Arundinella anomala Steud., two flooding resistant riparian species, have been examined in a rhizotron environment. Short-time (2 days waterlogging, 2 days flooding, 2 days recovery) flooding cycles in the original substrate and long time (14 days waterlogging, flooding, recovery) flooding cycles, in original substrate and sterile glass bead substrate, have been simulated in floodable two-way access rhizotrons. Oxygen- and pH-sensitive foils (planar optodes, PreSens) automatically monitored root reaction in a confined space (2cm2 each) on the backside of the rhizotron, while soil solution samples were taken 2 times a day from the other side of the rhizotron at the corresponding area through filter and steel capillaries. The samples were analyzed by capillary electrophoresis for low molecular weight organic acids (LMWOA, i.e. oxalic, formic, succinic, malic, acetic, glyoxylic, lactic and citric acid). Results show diurnal rhythms of rhizospheric acidification for both species in high resolution, combined with oxygen entry into the root surrounding during waterlogged state. Flooding caused stronger acidification in the rhizosphere, that were however not accompanied by increased occurrence of LMWOA except for acetic and glyoxylic acid. First results from longer flooding periods show stable diurnal rhythms during waterlogging, but no strongly increased activity during the flooding event. Performance of the two species is not hampered by being waterlogged, and they follow a silencing strategy during a longer phase of anoxia without

Probabilistic Flood Mapping using Volunteered Geographical Information

Science.gov (United States)

Rivera, S. J.; Girons Lopez, M.; Seibert, J.; Minsker, B. S.

2016-12-01

Flood extent maps are widely used by decision makers and first responders to provide critical information that prevents economic impacts and the loss of human lives. These maps are usually obtained from sensory data and/or hydrologic models, which often have limited coverage in space and time. Recent developments in social media and communication technology have created a wealth of near-real-time, user-generated content during flood events in many urban areas, such as flooded locations, pictures of flooding extent and height, etc. These data could improve decision-making and response operations as events unfold. However, the integration of these data sources has been limited due to the need for methods that can extract and translate the data into useful information for decision-making. This study presents an approach that uses volunteer geographic information (VGI) and non-traditional data sources (i.e., Twitter, Flicker, YouTube, and 911 and 311 calls) to generate/update the flood extent maps in areas where no models and/or gauge data are operational. The approach combines Web-crawling and computer vision techniques to gather information about the location, extent, and water height of the flood from unstructured textual data, images, and videos. These estimates are then used to provide an updated flood extent map for areas surrounding the geo-coordinate of the VGI through the application of a Hydro Growing Region Algorithm (HGRA). HGRA combines hydrologic and image segmentation concepts to estimate a probabilistic flooding extent along the corresponding creeks. Results obtained for a case study in Austin, TX (i.e., 2015 Memorial Day flood) were comparable to those obtained by a calibrated hydrologic model and had good spatial correlation with flooding extents estimated by the Federal Emergency Management Agency (FEMA).

Changes in the timing and magnitude of floods in Canada

International Nuclear Information System (INIS)

Cunderlik, J.M.; Ouarda, T.B.M.J.

2008-01-01

It is expected that the global climate change will have significant impacts on the regime of hydrologic extremes. An increase in both the frequency and magnitude of hydrologic extremes is anticipated in the near future. As a consequence, the design and operation of water resource systems will have to adapt to the changing regime of hydrologic extremes. This study explores trends in the timing and magnitude of floods in natural streamflow gauging stations in Canada. The seasonality of floods is analyzed and the selected streamflow stations grouped into five flood seasonality regions. A common 30-year long observation period from 1974 to 2003 is used in the analysis to eliminate the effect of hydro-climatic variability in the timing and magnitude of floods resulting from different observation periods. The timing of floods is described in terms of directional statistics. A method is developed for analyzing trends in directional dates of flood occurrence that is not affected by the choice of zero direction. The magnitude of floods is analyzed by the annual maximum and peak-over-threshold methods. Trends in the timing and magnitude of floods are identified in each flood seasonality region using the Mann-Kendall nonparametric test, with a modification for auto-correlated data. The results show a good correspondence between the identified flood seasonality regions and the main terrestrial zones in Canada. Significant changes in the timing and magnitude of floods are found in the flood seasonality regions. (author)

Computerized evaluation of flood impact

International Nuclear Information System (INIS)

Gagnon, J.; Quach, T.T.; Marche, C.; Lessard, G.

1998-01-01

A computerized evaluation process for assessing the economic impacts of a potential dam failure is described. The DOMINO software, which was developed by Hydro-Quebec, takes into account flow data from dam break simulations of floods, the territory involved, plus the economic evaluations of the real estate and infrastructures affected. Some examples of software applications and impact evaluations are presented. The principal elements involved in estimating economic or other types of impacts induced by natural flooding or dam failure, are: (1) flow forecasting, (2) defining the contour of the involved territory, and (3) accounting for the various impacts identified in the affected zone. Owing to its wide range of functions and utilities, DOMINO has proven to be a very useful, user-friendly and portable decision-making tool. 5 refs., 6 tabs

Radiation-sanitary essessment of surface and ground water sources in the Chernobyl' NPP 30-km zone

International Nuclear Information System (INIS)

Prokopov, V.A.; Karachev, I.I.; Nagovitsina, L.I.; Borovikova, N.M.; Tolstopyatova, G.V.; Gelts, V.I.; Malenko, N.D.; Dan'ko, O.P.

1992-01-01

The quality of drinking water in artesian water-lines of the Pripyat' and Chernobyl' settlements fro the period of 1987-1991 is estimated. The flood-lands territory within the north trace boundaries, where Sr 90 activity amounts to approximately 10000 Ci, contributes most importantly into water contamination of the Pripyat' river and its tributaries. The portion of contaminated drains from flood-lands territory amounts to 40% and more of the 90 Sr intake from all sources of the Pripyat' river contamination. Essessment of the artesian water quality shows that drinking water is innocuous for health in respect to its composition. 90 Sr and 137 Cs content in artesian water in the Pripyat' and Chernobyl' settlements is lower than the maximum permissible concentration. 5 refs.; 1 tab

A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

NARCIS (Netherlands)

Balugani, E.; Lubczynski, M.; Metselaar, K.A.

2016-01-01

Sourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its implementation in dedicated post-processing

Evaluating four-dimensional time-lapse electrical resistivity tomography for monitoring DNAPL source zone remediation.

Science.gov (United States)

Power, Christopher; Gerhard, Jason I; Karaoulis, Marios; Tsourlos, Panagiotis; Giannopoulos, Antonios

2014-07-01

Practical, non-invasive tools do not currently exist for mapping the remediation of dense non-aqueous phase liquids (DNAPLs). Electrical resistivity tomography (ERT) exhibits significant potential but has not yet become a practitioner's tool due to challenges in interpreting the survey results at real sites. This study explores the effectiveness of recently developed four-dimensional (4D, i.e., 3D space plus time) time-lapse surface ERT to monitor DNAPL source zone remediation. A laboratory experiment demonstrated the approach for mapping a changing NAPL distribution over time. A recently developed DNAPL-ERT numerical model was then employed to independently simulate the experiment, providing confidence that the DNAPL-ERT model is a reliable tool for simulating real systems. The numerical model was then used to evaluate the potential for this approach at the field scale. Four DNAPL source zones, exhibiting a range of complexity, were initially simulated, followed by modeled time-lapse ERT monitoring of complete DNAPL remediation by enhanced dissolution. 4D ERT inversion provided estimates of the regions of the source zone experiencing mass reduction with time. Results show that 4D time-lapse ERT has significant potential to map both the outline and the center of mass of the evolving treated portion of the source zone to within a few meters in each direction. In addition, the technique can provide a reasonable, albeit conservative, estimate of the DNAPL volume remediated with time: 25% underestimation in the upper 2m and up to 50% underestimation at late time between 2 and 4m depth. The technique is less reliable for identifying cleanup of DNAPL stringers outside the main DNAPL body. Overall, this study demonstrates that 4D time-lapse ERT has potential for mapping where and how quickly DNAPL mass changes in real time during site remediation. Copyright © 2014 Elsevier B.V. All rights reserved.

Iowa Flood Information System

Science.gov (United States)

Demir, I.; Krajewski, W. F.; Goska, R.; Mantilla, R.; Weber, L. J.; Young, N.

2011-12-01

The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts both short-term and seasonal, flood-related data, information and interactive visualizations for communities in Iowa. The key element of the system's architecture is the notion of community. Locations of the communities, those near streams and rivers, define basin boundaries. The IFIS provides community-centric watershed and river characteristics, weather (rainfall) conditions, and streamflow data and visualization tools. Interactive interfaces allow access to inundation maps for different stage and return period values, and flooding scenarios with contributions from multiple rivers. Real-time and historical data of water levels, gauge heights, and rainfall conditions are available in the IFIS by streaming data from automated IFC bridge sensors, USGS stream gauges, NEXRAD radars, and NWS forecasts. Simple 2D and 3D interactive visualizations in the IFIS make the data more understandable to general public. Users are able to filter data sources for their communities and selected rivers. The data and information on IFIS is also accessible through web services and mobile applications. The IFIS is optimized for various browsers and screen sizes to provide access through multiple platforms including tablets and mobile devices. The IFIS includes a rainfall-runoff forecast model to provide a five-day flood risk estimate for around 500 communities in Iowa. Multiple view modes in the IFIS accommodate different user types from general public to researchers and decision makers by providing different level of tools and details. River view mode allows users to visualize data from multiple IFC bridge sensors and USGS stream gauges to follow flooding condition along a river. The IFIS will help communities make better-informed decisions on the occurrence of floods, and will alert communities

A new refillable Cobalt-57 flood phantom to measure camera uniformity

International Nuclear Information System (INIS)

Dias-Neto, A.; Silva, C.P.G. da; Osso, J.

1997-01-01

Full text: The system uniformity of a scintillation camera is assessed using an extended Tc-99m source: a well constructed flood phantom, filled with a solution of Tc-99m pertechnetate, that does not bulge and is well mixed. A convenient substitute is a commercial solid Co-57 sheet source, which is expensive (5k-10k USS), has a relative short life-span (1,5 - 2 years), and, may not be quite uniform. As an alternative, an inexpensive fillable Co-57 flood source is presented. For pilot testing, a plastic flood phantom was filled with a solution of Co-57 chloride produced by IPEN's cyclotron. Special filling plugs with O-rings were used to avoid any leakage. High count uniformity images, using a low-energy high-resolution collimator and 15% energy windows, were obtained with the fillable Co-57 source, a commercial Co-57 sheet source, and a Tc-99 source. The data were compared visually and quantified with the NEMA uniformity parameters. The fillable Co-57 source compared favourably with the other sources. A shock-proof flood phantom is at present under development. This phantom is intended to be refilled annually with Co-57, at a fraction of the cost of a commercial sheet source. (authors)

STUDY REGARDING DELINEATION OF FLOOD HAZARD ZONES IN THE HYDROGRAPHIC BASIN OF THE SOMEŞ RIVER, BORDER AREA

Directory of Open Access Journals (Sweden)

STOICA F.

2014-03-01

Full Text Available The hydrological studies will provide the characteristic parameters for the floods occurred for the calculus discharges with overflow probabilities of 0,1%; 1%, 5%, 10%. The hydrologic and hydraulic models will be made by using the hydro-meteorological data base and the topographical measurements on site; them calibration will be done according to the records of the historical floods. The studies on the hydrologic and hydraulic models will be necessary for the establishment of the carrying capacity of the riverbeds, for the delimitation of the flood plains and for the detection of the transit discharges at the hydro-technical installations, but also for the establishment of the parameters needed for the structural measures’ projects. These will be based on the 1D and 2D unstable hydro-dynamic models. Therefore, the users would be able to assess the proposed measures and the impact over the river’s system; of course with the potential combination of the 1D and 2D. The main objectives followed by the project are: • identification of the river basins or river sub-basins with flood risks; • regionalization of the flood hazard; • presentation of the main flash floods occurred during the last 30 years, which induced floods; • assessment of the consequences of eventual flood over the population, properties and environment; • the establishment of the protection degree, accepted for the human settlements, for the economic and social objectives, for the farm areas, etc.;

Real-time flood extent maps based on social media

Science.gov (United States)

Eilander, Dirk; van Loenen, Arnejan; Roskam, Ruud; Wagemaker, Jurjen

2015-04-01

During a flood event it is often difficult to get accurate information about the flood extent and the people affected. This information is very important for disaster risk reduction management and crisis relief organizations. In the post flood phase, information about the flood extent is needed for damage estimation and calibrating hydrodynamic models. Currently, flood extent maps are derived from a few sources such as satellite images, areal images and post-flooding flood marks. However, getting accurate real-time or maximum flood extent maps remains difficult. With the rise of social media, we now have a new source of information with large numbers of observations. In the city of Jakarta, Indonesia, the intensity of unique flood related tweets during a flood event, peaked at 8 tweets per second during floods in early 2014. A fair amount of these tweets also contains observations of water depth and location. Our hypothesis is that based on the large numbers of tweets it is possible to generate real-time flood extent maps. In this study we use tweets from the city of Jakarta, Indonesia, to generate these flood extent maps. The data-mining procedure looks for tweets with a mention of 'banjir', the Bahasa Indonesia word for flood. It then removes modified and retweeted messages in order to keep unique tweets only. Since tweets are not always sent directly from the location of observation, the geotag in the tweets is unreliable. We therefore extract location information using mentions of names of neighborhoods and points of interest. Finally, where encountered, a mention of a length measure is extracted as water depth. These tweets containing a location reference and a water level are considered to be flood observations. The strength of this method is that it can easily be extended to other regions and languages. Based on the intensity of tweets in Jakarta during a flood event we can provide a rough estimate of the flood extent. To provide more accurate flood extend

A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

NARCIS (Netherlands)

Balugani, E.; Lubczynski, M.W.; Metselaar, Klaas

2016-01-01

Sourcing subsurface evaporation (E_ss) into groundwater (E_g) and unsaturated zone (E_u) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its

Flood risk assessment through 1D/2D couple HEC-RAS hydrodynamic modeling- A case study of Surat City, Lower Tapi Basin, India

Science.gov (United States)

Patel, Dhruvesh; Ramirez, Jorge; Srivastava, Prashant; Bray, Michaela; Han, Dawei

2017-04-01

Surat, known as the diamond city of Gujart is situated 100 km downstream of Ukai dam and near the mouth of river Tapi and affected by the flood at every alternate year. The city experienced catastrophic floods in 1933, 1959, 1968, 1970, 1994, 1998 and 2006. It is estimated that a single flood event during August 6-12, 2006 in Surat and Hazira twin-city, caused heavy damages, resulted in the death of 300 people and property damage worth € 289 million. The peak discharge of 25768 m3 s-1 release from Ukai dam was responsible for the disastrous flood in Surat city. To identifylow lying areas prone to inundation and reduce the uncertainty in flood mitigation measures, HEC-RAS based 1D/2D Couple hydrodynamic modeling is carried out for Surat city. Release from the Ukai dam and tidal level of the sea are considered for upstream and downstream boundary condition. 299 surveyed cross-sections have been considered for 1D modeling, whereas a topographic map at 0.5 m contour interval was used to produce a 5 m grid and SRTM (30 & 90 m) grid has been considered for Suart and Lower Tapi Basin (LTB). Flow is simulated under unsteady conditions, calibrated for the year 1998 and validated for the year 2006. The simulated result shows that the 9th August 18.00 hr was the worst day for Surat city and maximum 75-77 % area was under inundation. Most of the flooded area experienced 0.25 m/s water velocity with the duration of 90 hr. Due to low velocity and high duration of the flood, a low lying area within the west zone and south-west zone of the city was badly affected by the flood, whereas the south zone and south-east zone was least. Simulated results show good correlation when compared with an observed flood level map. The simulated results will be helpful to improve the flood resilience strategy at Surat city and reduce the uncertainty for flood inundation mapping for future dam releases. The present case study shows the applicability of 1D/2D coupled hydrodynamic modeling for

Identification of urban flood vulnerability in eastern Slovakia by mapping the potential natural sources of flooding - implications for territorial planning

Directory of Open Access Journals (Sweden)

Lenka Gaňová

2017-12-01

Full Text Available The aim of the presented study was to assess the distribution of flood-risk potential (FRP at the regional scale. A progressive approach integrating geographical information system (GIS with two different methods of multicriteria analysis (MCA – analytic hierarchy process (AHP and ranking method (RM was applied in the process. In the analyses, the most causative factors for flooding were taken into account, urban spatial planning, such as soil type, daily precipitation, land use, size of the catchment and average basin slope. A case study of flood vulnerability identification in the Hornád and Bodrog catchments’ areas in eastern Slovakia has been employed to illustrate two different approaches. Spatial estimation of FRP should be one of the basic steps for complex geoecological evaluation and delimitation of landscape considering water resources management, groundwater pollution, prediction of soil erosion and sediment transport and some other important landscape-ecological factors. The obtained results indicate that RM method shows better results as related to the existing floods in the recent years in Bodrog and Hornád catchment than AHP method.

Lessons Learned from Missing Flooding Barriers Operating Experience

International Nuclear Information System (INIS)

Simic, Z.; Veira, M. P.

2016-01-01

Flooding hazard is highly significant for nuclear power plant safety because of its potential for common cause impact on safety related systems, and because operating experience reviews regularly identify flooding as a cause of concern. Source of the flooding could be external (location) or internal (plant design). The amount of flooding water could vary but even small amount might suffice to affect redundant trains of safety related systems for power supply and cooling. The protection from the flooding is related to the design-basis flood level (DBFL) and it consists of three elements: structural, organizational and accessibility. Determination of the DBFL is critical, as Fukushima Daiichi accident terribly proved. However, as the topic of flooding is very broad, the scope of this paper is focused only on the issues related to the missing flood barriers. Structural measures are physically preventing flooding water to reach or damage safety related system, and they could be permanent or temporary. For temporary measures it is important to have necessary material, equipment and organizational capacity for the timely implementation. Maintenance is important for permanent protection and periodical review is important for assuring readiness and feasibility of temporary flooding protection. Final flooding protection element is assured accessibility to safety related systems during the flooding. Appropriate flooding protection is based on the right implementation of design requirements, proper maintenance and periodic reviews. Operating experience is constantly proving how numerous water sources and systems interactions make flooding protection challenging. This paper is presenting recent related operating experience feedback involving equipment, procedures and analysis. Most frequent deficiencies are: inadequate, degraded or missing seals that would allow floodwaters into safety related spaces. Procedures are inadequate typically because they underestimate necessary

The response of source-bordering aeolian dunefields to sediment-supply changes 2: Controlled floods of the Colorado River in Grand Canyon, Arizona, USA

Science.gov (United States)

Sankey, Joel B.; Caster, Joshua; Kasprak, Alan; East, Amy E.

2018-06-01

In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado River in 2012, 2013, 2014, and 2016. We find that aeolian sediment resupply unambiguously occurred in 8 of the 16 instances of controlled flooding adjacent to SBDs. Resupply attributed to individual floods varied substantially among sites, and occurred with four, three, one, and zero floods at the four sites, respectively. We infer that the relative success of controlled floods as a regulated-river management tool for resupplying sediment to SBDs is analogous to the frequency of resupply observed for fluvial sandbars in this setting, in that sediment resupply was estimated to have occurred for roughly half of the instances of recent controlled flooding at sandbars monitored separately from this study. We find the methods developed in this, and a companion study, are effective tools to quantify geomorphic changes in sediment storage, along linked fluvial and aeolian pathways of sedimentary systems.

The response of source-bordering aeolian dunefields to sediment-supply changes 2: Controlled floods of the Colorado River in Grand Canyon, Arizona, USA

Science.gov (United States)

Sankey, Joel B.; Caster, Joshua; Kasprak, Alan; East, Amy

2018-01-01

In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado River in 2012, 2013, 2014, and 2016. We find that aeolian sediment resupply unambiguously occurred in 8 of the 16 instances of controlled flooding adjacent to SBDs. Resupply attributed to individual floods varied substantially among sites, and occurred with four, three, one, and zero floods at the four sites, respectively. We infer that the relative success of controlled floods as a regulated-river management tool for resupplying sediment to SBDs is analogous to the frequency of resupply observed for fluvial sandbars in this setting, in that sediment resupply was estimated to have occurred for roughly half of the instances of recent controlled flooding at sandbars monitored separately from this study. We find the methods developed in this, and a companion study, are effective tools to quantify geomorphic changes in sediment storage, along linked fluvial and aeolian pathways of sedimentary systems.

Classification of mechanisms, climatic context, areal scaling, and synchronization of floods: the hydroclimatology of floods in the Upper Paraná River basin, Brazil

Directory of Open Access Journals (Sweden)

C. H. R. Lima

2017-12-01

Full Text Available Floods are the main natural disaster in Brazil, causing substantial economic damage and loss of life. Studies suggest that some extreme floods result from a causal climate chain. Exceptional rain and floods are determined by large-scale anomalies and persistent patterns in the atmospheric and oceanic circulations, which influence the magnitude, extent, and duration of these extremes. Moreover, floods can result from different generating mechanisms. These factors contradict the assumptions of homogeneity, and often stationarity, in flood frequency analysis. Here we outline a methodological framework based on clustering using self-organizing maps (SOMs that allows the linkage of large-scale processes to local-scale observations. The methodology is applied to flood data from several sites in the flood-prone Upper Paraná River basin (UPRB in southern Brazil. The SOM clustering approach is employed to classify the 6-day rainfall field over the UPRB into four categories, which are then used to classify floods into four types based on the spatiotemporal dynamics of the rainfall field prior to the observed flood events. An analysis of the vertically integrated moisture fluxes, vorticity, and high-level atmospheric circulation revealed that these four clusters are related to known tropical and extratropical processes, including the South American low-level jet (SALLJ; extratropical cyclones; and the South Atlantic Convergence Zone (SACZ. Persistent anomalies in the sea surface temperature fields in the Pacific and Atlantic oceans are also found to be associated with these processes. Floods associated with each cluster present different patterns in terms of frequency, magnitude, spatial variability, scaling, and synchronization of events across the sites and subbasins. These insights suggest new directions for flood risk assessment, forecasting, and management.

Classification of mechanisms, climatic context, areal scaling, and synchronization of floods: the hydroclimatology of floods in the Upper Paraná River basin, Brazil

Science.gov (United States)

Lima, Carlos H. R.; AghaKouchak, Amir; Lall, Upmanu

2017-12-01

Floods are the main natural disaster in Brazil, causing substantial economic damage and loss of life. Studies suggest that some extreme floods result from a causal climate chain. Exceptional rain and floods are determined by large-scale anomalies and persistent patterns in the atmospheric and oceanic circulations, which influence the magnitude, extent, and duration of these extremes. Moreover, floods can result from different generating mechanisms. These factors contradict the assumptions of homogeneity, and often stationarity, in flood frequency analysis. Here we outline a methodological framework based on clustering using self-organizing maps (SOMs) that allows the linkage of large-scale processes to local-scale observations. The methodology is applied to flood data from several sites in the flood-prone Upper Paraná River basin (UPRB) in southern Brazil. The SOM clustering approach is employed to classify the 6-day rainfall field over the UPRB into four categories, which are then used to classify floods into four types based on the spatiotemporal dynamics of the rainfall field prior to the observed flood events. An analysis of the vertically integrated moisture fluxes, vorticity, and high-level atmospheric circulation revealed that these four clusters are related to known tropical and extratropical processes, including the South American low-level jet (SALLJ); extratropical cyclones; and the South Atlantic Convergence Zone (SACZ). Persistent anomalies in the sea surface temperature fields in the Pacific and Atlantic oceans are also found to be associated with these processes. Floods associated with each cluster present different patterns in terms of frequency, magnitude, spatial variability, scaling, and synchronization of events across the sites and subbasins. These insights suggest new directions for flood risk assessment, forecasting, and management.

Identification of flood-rich and flood-poor periods in flood series

Science.gov (United States)

Mediero, Luis; Santillán, David; Garrote, Luis

2015-04-01

Recently, a general concern about non-stationarity of flood series has arisen, as changes in catchment response can be driven by several factors, such as climatic and land-use changes. Several studies to detect trends in flood series at either national or trans-national scales have been conducted. Trends are usually detected by the Mann-Kendall test. However, the results of this test depend on the starting and ending year of the series, which can lead to different results in terms of the period considered. The results can be conditioned to flood-poor and flood-rich periods located at the beginning or end of the series. A methodology to identify statistically significant flood-rich and flood-poor periods is developed, based on the comparison between the expected sampling variability of floods when stationarity is assumed and the observed variability of floods in a given series. The methodology is applied to a set of long series of annual maximum floods, peaks over threshold and counts of annual occurrences in peaks over threshold series observed in Spain in the period 1942-2009. Mediero et al. (2014) found a general decreasing trend in flood series in some parts of Spain that could be caused by a flood-rich period observed in 1950-1970, placed at the beginning of the flood series. The results of this study support the findings of Mediero et al. (2014), as a flood-rich period in 1950-1970 was identified in most of the selected sites. References: Mediero, L., Santillán, D., Garrote, L., Granados, A. Detection and attribution of trends in magnitude, frequency and timing of floods in Spain, Journal of Hydrology, 517, 1072-1088, 2014.

Utilising social media contents for flood inundation mapping

Science.gov (United States)

Schröter, Kai; Dransch, Doris; Fohringer, Joachim; Kreibich, Heidi

2016-04-01

Data about the hazard and its consequences are scarce and not readily available during and shortly after a disaster. An information source which should be explored in a more efficient way is eyewitness accounts via social media. This research presents a methodology that leverages social media content to support rapid inundation mapping, including inundation extent and water depth in the case of floods. It uses quantitative data that are estimated from photos extracted from social media posts and their integration with established data. Due to the rapid availability of these posts compared to traditional data sources such as remote sensing data, areas affected by a flood, for example, can be determined quickly. Key challenges are to filter the large number of posts to a manageable amount of potentially useful inundation-related information, and to interpret and integrate the posts into mapping procedures in a timely manner. We present a methodology and a tool ("PostDistiller") to filter geo-located posts from social media services which include links to photos and to further explore this spatial distributed contextualized in situ information for inundation mapping. The June 2013 flood in Dresden is used as an application case study in which we evaluate the utilization of this approach and compare the resulting spatial flood patterns and inundation depths to 'traditional' data sources and mapping approaches like water level observations and remote sensing flood masks. The outcomes of the application case are encouraging. Strengths of the proposed procedure are that information for the estimation of inundation depth is rapidly available, particularly in urban areas where it is of high interest and of great value because alternative information sources like remote sensing data analysis do not perform very well. The uncertainty of derived inundation depth data and the uncontrollable availability of the information sources are major threats to the utility of the approach.

Comparing flood loss models of different complexity

Science.gov (United States)

Schröter, Kai; Kreibich, Heidi; Vogel, Kristin; Riggelsen, Carsten; Scherbaum, Frank; Merz, Bruno

2013-04-01

Any deliberation on flood risk requires the consideration of potential flood losses. In particular, reliable flood loss models are needed to evaluate cost-effectiveness of mitigation measures, to assess vulnerability, for comparative risk analysis and financial appraisal during and after floods. In recent years, considerable improvements have been made both concerning the data basis and the methodological approaches used for the development of flood loss models. Despite of that, flood loss models remain an important source of uncertainty. Likewise the temporal and spatial transferability of flood loss models is still limited. This contribution investigates the predictive capability of different flood loss models in a split sample cross regional validation approach. For this purpose, flood loss models of different complexity, i.e. based on different numbers of explaining variables, are learned from a set of damage records that was obtained from a survey after the Elbe flood in 2002. The validation of model predictions is carried out for different flood events in the Elbe and Danube river basins in 2002, 2005 and 2006 for which damage records are available from surveys after the flood events. The models investigated are a stage-damage model, the rule based model FLEMOps+r as well as novel model approaches which are derived using data mining techniques of regression trees and Bayesian networks. The Bayesian network approach to flood loss modelling provides attractive additional information concerning the probability distribution of both model predictions and explaining variables.

Estimation of Damage Costs Associated with Flood Events

Science.gov (United States)

Andrews, T. A.; Wauthier, C.; Zipp, K.

2017-12-01

This study investigates the possibility of creating a mathematical function that enables the estimation of flood-damage costs. We begin by examining the costs associated with past flood events in the United States. The data on these tropical storms and hurricanes are provided by the National Oceanic and Atmospheric Administration. With the location, extent of flooding, and damage reparation costs identified, we analyze variables such as: number of inches rained, land elevation, type of landscape, region development in regards to building density and infrastructure, and population concentration. We seek to identify the leading drivers of high flood-damage costs and understand which variables play a large role in the costliness of these weather events. Upon completion of our mathematical analysis, we turn out attention to the 2017 natural disaster of Texas. We divide the region, as we did above, by land elevation, type of landscape, region development in regards to building density and infrastructure, and population concentration. Then, we overlay the number of inches rained in those regions onto the divided landscape and apply our function. We hope to use these findings to estimate the potential flood-damage costs of Hurricane Harvey. This information is then transformed into a hazard map that could provide citizens and businesses of flood-stricken zones additional resources for their insurance selection process.

A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

OpenAIRE

Balugani, E.; Lubczynski, M.W.; Metselaar, Klaas

2016-01-01

Sourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its implementation in dedicated post-processing software called SOURCE (used along with the HYDRUS1D model), to study evaporation sourcing dynamics, define quantitatively “shallow” and “deep” water table conditions and test the applicability of wa...

BDHI: a French national database on historical floods

Directory of Open Access Journals (Sweden)

Lang Michel

2016-01-01

Full Text Available The paper describes the various features of the BDHI database (objects, functions, content. This document database provides document sheets on historical floods from various sources: technical reports from water authorities, scientific accounts (meteorology, hydrology, hydraulics..., post-disaster reports, newspapers or book extracts... It is complemented by fact sheets on flood events, which provide a summary text on significant past floods: location, date and duration, type of flood, extent, probability, adverse consequences A search engine is provided for information search based on time (specific date or period, on location (district, basin, city or thematic topic (document type, flood type, flood magnitude, flood impact.... We conclude by some future challenges in relation to the next cycle of the Floods Directive (2016-2022, with the inventory of past floods which had significant adverse impacts. What are the flood events that need to be integrated (new ones later than 2011 and/or previous floods that had not yet been selected? How can the process of historical data integration be extended at a local scale, with an adequate process of validation? How to promote the use of BDHI database in relation with the development of the culture of risk?

Comparisons of Source Characteristics between Recent Inland Crustal Earthquake Sequences inside and outside of Niigata-Kobe Tectonic Zone, Japan

Science.gov (United States)

Somei, K.; Asano, K.; Iwata, T.; Miyakoshi, K.

2012-12-01

After the 1995 Kobe earthquake, many M7-class inland earthquakes occurred in Japan. Some of those events (e.g., the 2004 Chuetsu earthquake) occurred in a tectonic zone which is characterized as a high strain rate zone by the GPS observation (Sagiya et al., 2000) or dense distribution of active faults. That belt-like zone along the coast in Japan Sea side of Tohoku and Chubu districts, and north of Kinki district, is called as the Niigata-Kobe tectonic zone (NKTZ, Sagiya et al, 2000). We investigate seismic scaling relationship for recent inland crustal earthquake sequences in Japan and compare source characteristics between events occurring inside and outside of NKTZ. We used S-wave coda part for estimating source spectra. Source spectral ratio is obtained by S-wave coda spectral ratio between the records of large and small events occurring close to each other from nation-wide strong motion network (K-NET and KiK-net) and broad-band seismic network (F-net) to remove propagation-path and site effects. We carefully examined the commonality of the decay of coda envelopes between event-pair records and modeled the observed spectral ratio by the source spectral ratio function with assuming omega-square source model for large and small events. We estimated the corner frequencies and seismic moment (ratio) from those modeled spectral ratio function. We determined Brune's stress drops of 356 events (Mw: 3.1-6.9) in ten earthquake sequences occurring in NKTZ and six sequences occurring outside of NKTZ. Most of source spectra obey omega-square source spectra. There is no obvious systematic difference between stress drops of events in NKTZ zone and others. We may conclude that the systematic tendency of seismic source scaling of the events occurred inside and outside of NKTZ does not exist and the average source scaling relationship can be effective for inland crustal earthquakes. Acknowledgements: Waveform data were provided from K-NET, KiK-net and F-net operated by

Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

Science.gov (United States)

2017-06-20

estimated viscosity of 3-4 cP.  Solutions-IES Novel Silica Gel/Veg-Oil Grout: 5 wt- % of emulsified vegetable oil (EVO), 10 wt-% of sodium...site must have a lower low permeability unit such as a clay to prevent up flow; and a four sided barrier is recommended (three sided barriers are...depth to groundwater (ង ft)  Transmissive zone preferably with an underlying clay layer  Good accessibility to source zone  Availability of

A methodology for flood risk appraisal in Lithuania

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Kriščiukaitienė Irena

2015-06-01

Full Text Available This paper presents a methodology for flood risk mapping as envisaged by the Directive on the Assessment and Management of Flood Risks [Directive 2007/60/EC]. Specifically, we aimed at identifying the types of flood damage that can be estimated given data availability in Lithuania. Furthermore, we present the main sources of data and the associated cost functions. The methodology covers the following main types of flood threats: risk to inhabitants, risk to economic activity, and social risk. A multi-criteria framework for aggregation of different risks is proposed to provide a comprehensive appraisal of flood risk. On the basis of the proposed research, flood risk maps have been prepared for Lithuania. These maps are available for each type of flood risk (i.e. inhabitants, economic losses, social risk as well as for aggregate risk. The results indicate that flood risk management is crucial for western and central Lithuania, whereas other parts of the country are not likely to suffer from significant losses due to flooding.

Hydrologic and hydraulic flood forecasting constrained by remote sensing data

Science.gov (United States)

Li, Y.; Grimaldi, S.; Pauwels, V. R. N.; Walker, J. P.; Wright, A. J.

2017-12-01

Flooding is one of the most destructive natural disasters, resulting in many deaths and billions of dollars of damages each year. An indispensable tool to mitigate the effect of floods is to provide accurate and timely forecasts. An operational flood forecasting system typically consists of a hydrologic model, converting rainfall data into flood volumes entering the river system, and a hydraulic model, converting these flood volumes into water levels and flood extents. Such a system is prone to various sources of uncertainties from the initial conditions, meteorological forcing, topographic data, model parameters and model structure. To reduce those uncertainties, current forecasting systems are typically calibrated and/or updated using ground-based streamflow measurements, and such applications are limited to well-gauged areas. The recent increasing availability of spatially distributed remote sensing (RS) data offers new opportunities to improve flood forecasting skill. Based on an Australian case study, this presentation will discuss the use of 1) RS soil moisture to constrain a hydrologic model, and 2) RS flood extent and level to constrain a hydraulic model.The GRKAL hydrological model is calibrated through a joint calibration scheme using both ground-based streamflow and RS soil moisture observations. A lag-aware data assimilation approach is tested through a set of synthetic experiments to integrate RS soil moisture to constrain the streamflow forecasting in real-time.The hydraulic model is LISFLOOD-FP which solves the 2-dimensional inertial approximation of the Shallow Water Equations. Gauged water level time series and RS-derived flood extent and levels are used to apply a multi-objective calibration protocol. The effectiveness with which each data source or combination of data sources constrained the parameter space will be discussed.

Flood tolerance of oak seedlings from bottomland and upland sites

Science.gov (United States)

Michael P. Walsh; Jerry Van Sambeek; Mark Coggeshall; David. Gwaze

2009-01-01

Artificial regeneration of oak species in floodplains presents numerous challenges because of the seasonal flooding associated with these areas. Utilizing not only flood-tolerant oak species, but also flood tolerant seed sources of the oak species, may serve to enhance seedling survival and growth rates. Despite the importance of these factors to hardwood forest...

Evaluation of sources, rates and methods of zinc fertilizer applications in flooded rice

International Nuclear Information System (INIS)

Sarkar, A.K.; Deb, D.L.

1981-01-01

A pot experiment was conducted using 65 Zn as tracer to evaluate the different sources, levels and methods of zinc fertilization in flooded rice. Results indicated that zinc sulphate was either at par or slightly superior to zincated urea from the point of view of yield and total zinc uptake by rice. The Zndff percent was found to be the highest with zincated urea and the lowest was observed with zinc oxide. 5 and 10 kg/ha levels of zinc were statistically at par in this regard. Among the different methods, surface application and thorough mixing with soil were comparable. Root dipping in 1 percent zinc oxide suspension and application of zinc in irrigation water also indicated high zinc absorption by the rice plant. (author)

Comparison of earthquake source parameters and interseismic plate coupling variations in global subduction zones (Invited)

Science.gov (United States)

Bilek, S. L.; Moyer, P. A.; Stankova-Pursley, J.

2010-12-01

Geodetically determined interseismic coupling variations have been found in subduction zones worldwide. These coupling variations have been linked to heterogeneities in interplate fault frictional conditions. These connections to fault friction imply that observed coupling variations are also important in influencing details in earthquake rupture behavior. Because of the wealth of newly available geodetic models along many subduction zones, it is now possible to examine detailed variations in coupling and compare to seismicity characteristics. Here we use a large catalog of earthquake source time functions and slip models for moderate to large magnitude earthquakes to explore these connections, comparing earthquake source parameters with available models of geodetic coupling along segments of the Japan, Kurile, Kamchatka, Peru, Chile, and Alaska subduction zones. In addition, we use published geodetic results along the Costa Rica margin to compare with source parameters of small magnitude earthquakes recorded with an onshore-offshore network of seismometers. For the moderate to large magnitude earthquakes, preliminary results suggest a complex relationship between earthquake parameters and estimates of strongly and weakly coupled segments of the plate interface. For example, along the Kamchatka subduction zone, these earthquakes occur primarily along the transition between strong and weak coupling, with significant heterogeneity in the pattern of moment scaled duration with respect to the coupling estimates. The longest scaled duration event in this catalog occurred in a region of strong coupling. Earthquakes along the transition between strong and weakly coupled exhibited the most complexity in the source time functions. Use of small magnitude (0.5 earthquake spectra, with higher corner frequencies and higher mean apparent stress for earthquakes that occur in along the Osa Peninsula relative to the Nicoya Peninsula, mimicking the along-strike variations in

Alluvial and riparian soils as major sources of lead exposure in young children in the Philippines: the role of floods.

Science.gov (United States)

Ostrea, Enrique M; Ostrea, Angelo M; Villanueva-Uy, Ma Esterlita; Chiodo, Lisa; Janisse, James

2015-04-01

The objective of this paper was to determine the prevalence and sources of high lead (Pb) exposure among children in Bulacan, Philippines. A total of 150 children (6-7 years old) and their caregivers were studied. Lead was analyzed in children hair and deciduous teeth. Sources of lead exposure were determined by caregiver interview and Pb analysis of house soil, drinking faucet water, air, and water from seven Bulacan rivers. Lead was positive in 91.3% of children's hair (MC or median concentration = 8.9 μg/g; range = 0-38.29), in 46.2% of the teeth (MC = 0.000 μg/mg in positive samples; range = 0.00-0.020), in 100% of soil (MC = 27.06 mg/kg; range = 3.05-1155.80), in 21.1% of air (MC = 0 μg/Ncm; range = 0-0.10), in 4% of house, faucet water (MC = 0.0 ppm; range = 0-40). There was a significant correlation (Spearman's rho) between Pb in children's hair and soil (r = 0.195; p = 0.017) and between Pb in house water and outdoor air (r = 0.616; p = 0.005). There is no significant correlation between Pb in children's hair and teeth. None of the potential sources of Pb from interview were related to lead exposure in the children. Water from seven Bulacan rivers was 100% positive for lead (MC = 70.00 ppb; range = 30-90). Widespread flooding with river overflow occurred in Bulacan in 2009 which likely caused lead contamination of the soil. There was no significant difference in the lead concentration of the soil whether near or far from the river (p = 0.205, Mann-Whitney U test). High lead exposure in children in Bulacan is likely from soil contaminated by lead-polluted rivers during flooding. In areas where flooding is common, alluvial and riparian soils from polluted rivers are important sources of lead exposure in children.

Assessment of dose contribution to population exposure from the radiation sources in the alienated Chernobyl zone

International Nuclear Information System (INIS)

Grodzinsky, D.M.; Francevych, L.K.; Koval, H.N.; Yakovlev, E.A.; Bezdrobny, Yu.V.; Proscura, N.I.; Pyantkowsky, V.L.

1997-01-01

The main dose load of Ukrainian population is caused by radionuclide-contamination of country territories, located outside the alienated zone, following Chernobyl accident. Besides, much attention could be devoted to the contribution of dose load on population, received from the radioactivity sources that were transferred out from the zone after accident. Present research and analysis of the available documents reflecting the transfer of radioactivity from the alienated zone, provided the estimates of dose load on population, resulting from transfer of the radioactivity sources via following channels: (1) direct surface flow; (2) underground waters; (3) wind-powdered route; (4) transfer with hydrobionts; (5) transfer during irrigation; (6) biogenic route; (7) transport routes and (8) route during wood transportation. Dynamics of radiation transfer through each channel was also studied for the post-accident period. Specific gravity of radioactivity transfer is determined in relation to dose load on Ukrainian population in different regions, in particular, in Dnipro river basin. The perspectives of radioactivity transfer via each of studied channels and its role in dose load on population were also analyzed. On the basis of present results the recommendations on possible arrangements are working out that aimed to reduce the dose contribution in population exposure by radioactivity source transfer from the alienated zone via channels that stipulate the largest dose loads and collective doses

Evaluating influence of active tectonics on spatial distribution pattern of floods along eastern Tamil Nadu, India

Science.gov (United States)

Selvakumar, R.; Ramasamy, SM.

2014-12-01

Flooding is a naturally recurrent phenomenon that causes severe damage to lives and property. Predictions on flood-prone zones are made based on intensity-duration of rainfall, carrying capacity of drainage, and natural or man-made obstructions. Particularly, the lower part of the drainage system and its adjacent geomorphic landforms like floodplains and deltaic plains are considered for analysis, but stagnation in parts of basins that are far away from major riverine systems is less unveiled. Similarly, uncharacteristic flooding in the upper and middle parts of drainage, especially in zones of an anomalous drainage pattern, is also least understood. Even though topographic differences are attributed for such anomalous spatial occurrence of floods, its genetic cause has to be identified for effective management practice. Added to structural and lithological variations, tectonic movements too impart micro-scale terrain undulations. Because active tectonic movements are slow-occurring, long-term geological processes, its resultant topographical variations and drainage anomalies are least correlated with floods. The recent floods of Tamil Nadu also exhibit a unique distribution pattern emphasizing the role of tectonics over it. Hence a detailed geoinformatics-based analysis was carried out to envisage the relationship between spatial distribution of flood and active tectonic elements such as regional arches and deeps, block faults, and graben and drainage anomalies such as deflected drainage, compressed meander, and eyed drainages. The analysis reveals that micro-scale topographic highs and lows imparted by active tectonic movements and its further induced drainage anomalies have substantially controlled the distribution pattern of flood.

A Location Intelligence System for the Assessment of Pluvial Flooding Risk and the Identification of Storm Water Pollutant Sources from Roads in Suburbanised Areas

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Szymon Szewrański

2018-06-01

Full Text Available The interplay of an ever-growing number of inhabitants, sprawl development, soil sealing, changes in urban traffic characteristics, as well as observed climate trends gives rise to more frequent pluvial flooding in cities, a higher run-off of water, and an increasing pollution of surface water. The aim of this research is to develop a location intelligence system for the assessment of pluvial flooding risks and the identification of storm water pollutant sources from roads in newly-developed areas. The system combines geographic information systems and business intelligence software, and it is based on the original Pluvial Flood Risk Assessment tool. The location intelligence system effectively identifies the spatial and temporal distribution of pluvial flood risks, allows to preliminarily evaluate the total run-off from roads, and helps localise potential places for new water management infrastructure. Further improvements concern the modelling of a flow accumulation and drainage system, the application of weather radar precipitation data, and traffic monitoring and modelling.

A software tool for rapid flood inundation mapping

Science.gov (United States)

Verdin, James; Verdin, Kristine; Mathis, Melissa L.; Magadzire, Tamuka; Kabuchanga, Eric; Woodbury, Mark; Gadain, Hussein

2016-06-02

The GIS Flood Tool (GFT) was developed by the U.S. Geological Survey with support from the U.S. Agency for International Development’s Office of U.S. Foreign Disaster Assistance to provide a means for production of reconnaissance-level flood inundation mapping for data-sparse and resource-limited areas of the world. The GFT has also attracted interest as a tool for rapid assessment flood inundation mapping for the Flood Inundation Mapping Program of the U.S. Geological Survey. The GFT can fill an important gap for communities that lack flood inundation mapping by providing a first-estimate of inundation zones, pending availability of resources to complete an engineering study. The tool can also help identify priority areas for application of scarce flood inundation mapping resources. The technical basis of the GFT is an application of the Manning equation for steady flow in an open channel, operating on specially processed digital elevation data. The GFT is implemented as a software extension in ArcGIS. Output maps from the GFT were validated at 11 sites with inundation maps produced previously by the Flood Inundation Mapping Program using standard one-dimensional hydraulic modeling techniques. In 80 percent of the cases, the GFT inundation patterns matched 75 percent or more of the one-dimensional hydraulic model inundation patterns. Lower rates of pattern agreement were seen at sites with low relief and subtle surface water divides. Although the GFT is simple to use, it should be applied with the oversight or review of a qualified hydraulic engineer who understands the simplifying assumptions of the approach.

Hurricane Harvey Riverine Flooding: Part 2: Integration of Heterogeneous Earth Observation Data for Comparative Analysis with High-Resolution Inundation Boundaries Reconstructed from Flood2D-GPU Model

Science.gov (United States)

Jackson, C.; Sava, E.; Cervone, G.

2017-12-01

Hurricane Harvey has been noted as the wettest cyclone on record for the US as well as the most destructive (so far) for the 2017 hurricane season. An entire year worth of rainfall occurred over the course of a few days. The city of Houston was greatly impacted as the storm lingered over the city for five days, causing a record-breaking 50+ inches of rain as well as severe damage from flooding. Flood model simulations were performed to reconstruct the event in order to better understand, assess, and predict flooding dynamics for the future. Additionally, number of remote sensing platforms, and on ground instruments that provide near real-time data have also been used for flood identification, monitoring, and damage assessment. Although both flood models and remote sensing techniques are able to identify inundated areas, rapid and accurate flood prediction at a high spatio-temporal resolution remains a challenge. Thus a methodological approach which fuses the two techniques can help to better validate what is being modeled and observed. Recent advancements in data fusion techniques of remote sensing with near real time heterogeneous datasets have allowed emergency responders to more efficiently extract increasingly precise and relevant knowledge from the available information. In this work the use of multiple sources of contributed data, coupled with remotely sensed and open source geospatial datasets is demonstrated to generate an understanding of potential damage assessment for the floods after Hurricane Harvey in Harris County, Texas. The feasibility of integrating multiple sources at different temporal and spatial resolutions into hydrodynamic models for flood inundation simulations is assessed. Furthermore the contributed datasets are compared against a reconstructed flood extent generated from the Flood2D-GPU model.

An application of Geographic Information System in mapping flood ...

African Journals Online (AJOL)

Roland

1Department of Geography, Benue State University, Makurdi, Benue State, Nigeria. 2National Agency for the Control of AIDS (NACA), Central Area, Abuja, Nigeria. Accepted 20 May, 2013. This study deals with the application of Geographic Information Systems (GIS) in mapping flood risk zones in Makurdi Town. This study ...

Analysis of potential flooding in the education Jatinangor based approach morphology, land cover, and geology

Science.gov (United States)

Rifai, Achmad; Hadian, Sapari Dwi; Mufti, Iqbal Jabbari; Fathoni, Azmi Rizqi; Azy, Fikri Noor; Jihadi, Lutfan Harisan

2017-07-01

Jatinangor formerly an agricultural area dominated by rice field. Water in Jatinangor comes from a spring located in north Jatinangor or proximal region of Manglayang mountain to flow to the south and southwest Jatinangor up to Citarum River. Jatinangor plain that was once almost all the rice fields, but now become a land settlement that grew very rapidly since its founding colleges. Flow and puddle were originally be used for agricultural land, but now turned into a disaster risks for humans. The research method using qualitative methods with the weighing factor, scoring, and overlay maps. The cause of the flood is distinguished into two: the first is the natural factors such as the condition of landform, lithology, river flow patterns, and annual rainfall. The second is non-natural factors such as land cover of settlement, irrigation, and land use. The amount of flood risks using probability Gilbert White frequency, magnitude and duration of existing events then correlated with these factors. Based on the results of the study, were divided into 3 zones Jatinangor disaster-prone (high, medium, and safe). High flood zone is located in the South Jatinangor which covers an area Cikeruh Village, Sayang Village, Cipacing village, Mekargalih village, Cintamulya village, west of Jatimukti village, and South Hegarmanah village, has a dominant causative factor is the use of solid land, poor drainage, lithology lacustrine conditions with low permeability, and flat topography. Medium flood zone was located in the central and western regions covering Cibeusi village, Cileles village, south of Cilayung village, Hegarmanah village and Padjadjaran Region, has a dominant causative factor is rather dense land use, lithology breccias and Tuffaceous Sand with moderate permeability, topography is moderately steep. Safe flood zone is located in the east Jatinangor covering Jatiroke village, Cisepur village, east Hegarmanah village, has a dominant factor in the form of a rather steep

Evaluating the Aquatic Habitat Potential of Flooded Polders in the Sacramento-San Joaquin Delta

Directory of Open Access Journals (Sweden)

John R. Durand

2017-12-01

Full Text Available https://doi.org/10.15447/sfews.2017v15iss4art4Large tracts of land in the Sacramento-San Joaquin Delta are subsided due to agricultural practices, creating polders up to 10 m below sea level that are vulnerable to flooding. As protective dikes breach, these become shallow, open water habitats that will not resemble any historical state. I investigated physical and biotic drivers of novel flooded polder habitat, using a Native Species Benefit Index (NSBI to predict the nature of future Delta ecosystems. Results suggest that flooded polders in the north Delta will have the ecology and fish community composition of a tidal river plain, those in the Cache-Lindsey Complex will have that of a tidal backwater, those in the confluence of the Sacramento and San Joaquin Rivers a brackish estuary, and those in the south Delta a fresh water lake. Flooded east-side Delta polders will likely be a transitional zone between south Delta lake-like ecosystems and north Delta tidal river plains. I compared each regional zone with the limited available literature and data on local fish assemblies to find support for NSBI predictions. Because flood probabilities and repair prioritization analyses suggest that polders in the south Delta are most likely to flood and be abandoned, without extensive intervention, much of the Delta will become a freshwater lake ecosystem, dominated by alien species. Proactive management of flooded tracts will nearly always hedge risks, save money and offer more functional habitats in the future; however, without proper immediate incentives, it will be difficult to encourage strong management practices.

Flood Risk Assessment as a Part of Integrated Flood and Drought Analysis. Case Study: Southern Thailand

Science.gov (United States)

Prabnakorn, Saowanit; Suryadi, Fransiscus X.; de Fraiture, Charlotte

2015-04-01

estuary downstream. Although the quantity of runoff increases slightly, the flooded areas downstream rises up significantly. After taking vulnerability map into account, the area with high risk of flooding where the decision makers should pay more attention on is at the downstream near the convergence of the river due to high vulnerability exposing to flood hazard. The anomaly of continuous high intensity of rainfall was the main cause of flooding. However, in respect of the information from casualties through the questionnaire, a lack of maintenance of the floodway was another factor exacerbating the impacts. The ambiguities of a sufficiency of drainage capacity and the water releasing from the dam are existent. This testimony affirms that societal interference is playing the major role in the degree of increasing losses from weather-climate extremes. The findings will be used for further study, especially for the proper land use planning and zoning which is lacking in many developing countries. Therefore, land use planning and adaptation might be part of a flood mitigation plan in conjunction with the structural measures.

Flood extent and water level estimation from SAR using data-model integration

Science.gov (United States)

Ajadi, O. A.; Meyer, F. J.

2017-12-01

Synthetic Aperture Radar (SAR) images have long been recognized as a valuable data source for flood mapping. Compared to other sources, SAR's weather and illumination independence and large area coverage at high spatial resolution supports reliable, frequent, and detailed observations of developing flood events. Accordingly, SAR has the potential to greatly aid in the near real-time monitoring of natural hazards, such as flood detection, if combined with automated image processing. This research works towards increasing the reliability and temporal sampling of SAR-derived flood hazard information by integrating information from multiple SAR sensors and SAR modalities (images and Interferometric SAR (InSAR) coherence) and by combining SAR-derived change detection information with hydrologic and hydraulic flood forecast models. First, the combination of multi-temporal SAR intensity images and coherence information for generating flood extent maps is introduced. The application of least-squares estimation integrates flood information from multiple SAR sensors, thus increasing the temporal sampling. SAR-based flood extent information will be combined with a Digital Elevation Model (DEM) to reduce false alarms and to estimate water depth and flood volume. The SAR-based flood extent map is assimilated into the Hydrologic Engineering Center River Analysis System (Hec-RAS) model to aid in hydraulic model calibration. The developed technology is improving the accuracy of flood information by exploiting information from data and models. It also provides enhanced flood information to decision-makers supporting the response to flood extent and improving emergency relief efforts.

A Methodology to Define Flood Resilience

Science.gov (United States)

Tourbier, J.

2012-04-01

Flood resilience has become an internationally used term with an ever-increasing number of entries on the Internet. The SMARTeST Project is looking at approaches to flood resilience through case studies at cities in various countries, including Washington D.C. in the United States. In light of U.S. experiences a methodology is being proposed by the author that is intended to meet ecologic, spatial, structural, social, disaster relief and flood risk aspects. It concludes that: "Flood resilience combines (1) spatial, (2) structural, (3) social, and (4) risk management levels of flood preparedness." Flood resilience should incorporate all four levels, but not necessarily with equal emphasis. Stakeholders can assign priorities within different flood resilience levels and the considerations they contain, dividing 100% emphasis into four levels. This evaluation would be applied to planned and completed projects, considering existing conditions, goals and concepts. We have long known that the "road to market" for the implementation of flood resilience is linked to capacity building of stakeholders. It is a multidisciplinary enterprise, involving the integration of all the above aspects into the decision-making process. Traditional flood management has largely been influenced by what in the UK has been called "Silo Thinking", involving constituent organizations that are responsible for different elements, and are interested only in their defined part of the system. This barrier to innovation also has been called the "entrapment effect". Flood resilience is being defined as (1) SPATIAL FLOOD RESILIENCE implying the management of land by floodplain zoning, urban greening and management to reduce storm runoff through depression storage and by practicing Sustainable Urban Drainage (SUD's), Best Management Practices (BMP's, or Low Impact Development (LID). Ecologic processes and cultural elements are included. (2) STRUCTURAL FLOOD RESILIENCE referring to permanent flood defense

Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone.

Science.gov (United States)

Cápiro, Natalie L; Löffler, Frank E; Pennell, Kurt D

2015-11-01

Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 μM) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0±1.3 and 4.0±1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (≥155 μM) and ethene (≥65 μM) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate

pH control for enhanced reductive bioremediation of chlorinated solvent source zones

International Nuclear Information System (INIS)

Robinson, Clare; Barry, D.A.; McCarty, Perry L.; Gerhard, Jason I.; Kouznetsova, Irina

2009-01-01

Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

Tacking Flood Risk from Watersheds using a Natural Flood Risk Management Toolkit

Science.gov (United States)

Reaney, S. M.; Pearson, C.; Barber, N.; Fraser, A.

2017-12-01

In the UK, flood risk management is moving beyond solely mitigating at the point of impact in towns and key infrastructure to tackle problem at source through a range of landscape based intervention measures. This natural flood risk management (NFM) approach has been trailed within a range of catchments in the UK and is moving towards being adopted as a key part of flood risk management. The approach offers advantages including lower cost and co-benefits for water quality and habitat creation. However, for an agency or group wishing to implement NFM within a catchment, there are two key questions that need to be addressed: Where in the catchment to place the measures? And how many measures are needed to be effective? With this toolkit, these questions are assessed with a two-stage workflow. First, SCIMAP-Flood gives a risk based mapping of likely locations that contribute to the flood peak. This tool uses information on land cover, hydrological connectivity, flood generating rainfall patterns and hydrological travel time distributions to impacted communities. The presented example applies the tool to the River Eden catchment, UK, with 5m grid resolution and hence provide sub-field scale information at the landscape extent. SCIMAP-Flood identifies sub-catchments where physically based catchment hydrological simulation models can be applied to test different NFM based mitigation measures. In this example, the CRUM3 catchment hydrological model has been applied within an uncertainty framework to consider the effectiveness of soil compaction reduction and large woody debris dams within a sub-catchment. It was found that large scale soil aeration to reduce soil compaction levels throughout the catchment is probably the most useful natural flood management measure for this catchment. NFM has potential for wide-spread application and these tools help to ensure that the measures are correctly designed and the scheme performance can be quantitatively assessed and predicted.

Remote Sensing and GIS Assessment of Flood Vulnerability of ...

African Journals Online (AJOL)

Lokoja, the Kogi state capital, is located at the Niger-Benue confluence. Hazards erupt when human activities in the confluence area are not properly managed. This article uses the Remote Sensing and GIS technique to assess the flood vulnerability zones of the town using the bench mark minimum and maximum water ...

Statistics and Analysis of the Relations between Rainstorm Floods and Earthquakes

Directory of Open Access Journals (Sweden)

Baodeng Hou

2016-01-01

Full Text Available The frequent occurrence of geophysical disasters under climate change has drawn Chinese scholars to pay their attention to disaster relations. If the occurrence sequence of disasters could be identified, long-term disaster forecast could be realized. Based on the Earth Degassing Effect (EDE which is valid, this paper took the magnitude, epicenter, and occurrence time of the earthquake, as well as the epicenter and occurrence time of the rainstorm floods as basic factors to establish an integrated model to study the correlation between rainstorm floods and earthquakes. 2461 severe earthquakes occurred in China or within 3000 km from China and the 169 heavy rainstorm floods occurred in China over the past 200+ years as the input data of the model. The computational results showed that although most of the rainstorm floods have nothing to do with the severe earthquakes from a statistical perspective, some floods might relate to earthquakes. This is especially true when the earthquakes happen in the vapor transmission zone where rainstorms lead to abundant water vapors. In this regard, earthquakes are more likely to cause big rainstorm floods. However, many cases of rainstorm floods could be found after severe earthquakes with a large extent of uncertainty.

Spatial analysis of landfills in respect to flood events and sea-level rise using ArcGIS Pro

OpenAIRE

Taylor, Benjamin S; Fei, Songlin

2017-01-01

"Recently in the news, media coverage of flood events has garnered attention due to tropical storms like Hurricane Harvey and the costly damages that resulted. Under climate change, events like sea-level rise (SLR) and flooding are projected to increase which threaten infrastructure, making it necessary for proper planning before, during, and after installation of landfills to mitigate risk. Studies in Austria and the UK have revealed that many landfills are located in flood zones in addition...

Earthquake spectra and near-source attenuation in the Cascadia subduction zone

Science.gov (United States)

Gomberg, J.; Creager, K.; Sweet, J.; Vidale, J.; Ghosh, A.; Hotovec, A.

2012-05-01

Models of seismic source displacement spectra are flat from zero to some corner frequency, fc, regardless of source type. At higher frequencies spectral models decay as f-1 for slow events and as f-2 for fast earthquakes. We show that at least in Cascadia, wave propagation effects likely control spectral decay rates above ˜2 Hz. We use seismograms from multiple small-aperture arrays to estimate the spectral decay rates of near-source spectra of 37 small `events' and find strong correlation between source location and decay rate. The decay rates (1) vary overall by an amount in excess of that inferred to distinguish slow sources from fast earthquakes, (2) are indistinguishable for sources separated by a few tens of km or less, and (3) separate into two populations that correlate with propagation through and outside a low-velocity zone imaged tomographically. We find that some events repeat, as is characteristic of low-frequency earthquakes (LFEs), but have spectra similar to those of non-repeating earthquakes. We also find no correlation between spectral decay rates and rates of ambient tremor activity. These results suggest that earthquakes near the plate boundary, at least in Cascadia, do not distinctly separate into `slow' and `fast' classes, and correctly accounting for propagation effects is necessary to characterize sources.

Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea

Science.gov (United States)

Brothers, Daniel; Kilb, Debi; Luttrell, Karen; Driscoll, Neal W.; Kent, Graham

2011-01-01

The southern San Andreas fault has not experienced a large earthquake for approximately 300 years, yet the previous five earthquakes occurred at ~180-year intervals. Large strike-slip faults are often segmented by lateral stepover zones. Movement on smaller faults within a stepover zone could perturb the main fault segments and potentially trigger a large earthquake. The southern San Andreas fault terminates in an extensional stepover zone beneath the Salton Sea—a lake that has experienced periodic flooding and desiccation since the late Holocene. Here we reconstruct the magnitude and timing of fault activity beneath the Salton Sea over several earthquake cycles. We observe coincident timing between flooding events, stepover fault displacement and ruptures on the San Andreas fault. Using Coulomb stress models, we show that the combined effect of lake loading, stepover fault movement and increased pore pressure could increase stress on the southern San Andreas fault to levels sufficient to induce failure. We conclude that rupture of the stepover faults, caused by periodic flooding of the palaeo-Salton Sea and by tectonic forcing, had the potential to trigger earthquake rupture on the southern San Andreas fault. Extensional stepover zones are highly susceptible to rapid stress loading and thus the Salton Sea may be a nucleation point for large ruptures on the southern San Andreas fault.

Flood Inundation Modelling in the Kuantan River Basin using 1D-2D Flood Modeller coupled with ASTER-GDEM

Science.gov (United States)

Ng, Z. F.; Gisen, J. I.; Akbari, A.

2018-03-01

Topography dataset is an important input in performing flood inundation modelling. However, it is always difficult to obtain high resolution topography that provide accurate elevation information. Fortunately, there are some open source topography datasets available with reasonable resolution such as SRTM and ASTER-GDEM. In Malaysia particularly in Kuantan, the modelling research on the floodplain area is still lacking. This research aims to: a) to investigate the suitability of ASTER-GDEM to be applied in the 1D-2D flood inundation modelling for the Kuantan River Basin; b) to generate flood inundation map for Kuantan river basin. The topography dataset used in this study is ASTER-GDEM to generate physical characteristics of watershed in the basin. It is used to perform rainfall runoff modelling for hydrological studies and to delineate flood inundation area in the Flood Modeller. The results obtained have shown that a 30m resolution ASTER-GDEM is applicable as an input for the 1D-2D flood modelling. The simulated water level in 2013 has NSE of 0.644 and RSME of 1.259. As a conclusion, ASTER-GDEM can be used as one alternative topography datasets for flood inundation modelling. However, the flood level obtained from the hydraulic modelling shows low accuracy at flat urban areas.

Flooding, flood risks and coping strategies in urban informal residential areas: The case of Keko Machungwa, Dar es Salaam, Tanzania

Directory of Open Access Journals (Sweden)

Tumpale Sakijege

2012-08-01

Full Text Available This article presents findings from a study carried out in Keko Machungwa informal settlement in Dar es Salaam under the auspices of the Disaster Management Training Centre of Ardhi University, Tanzania. The settlement has experienced frequent flooding in the past five years, and this study explores the causes, risks, extent of flooding and coping strategies of residents as well as municipality and city officials. Key methods employed in capturing empirical evidence included mapping of zones by severity of flooding, interviews with households, sub-ward leaders, and municipal and city officials. Non-participant observation, primarily taking photographs, complemented these methods. Laboratory tests of water samples taken from shallow wells in the settlement were performed to establish the level of pollution. In addition, records of prevalence of water-borne diseases were gathered from a dispensary within the settlement to corroborate flooding events, water pollution and occurrence of such diseases. Findings show that flooding is contributed to by the lack of a coordinated stormwater drainage system; haphazard housing development within the valley; and blocking of the water stream by haphazard dumping of solid waste and construction. Risks associated with flooding include water and air pollution, diseases, waterlogging and blocked accessibility. The most common coping strategies at household level are use of sandbags and tree logs; raised pit latrines and doorsteps; provision of water outlet pipes above plinth level; construction of embankments, protection walls and elevation of house foundations; seasonal displacement; and boiling and chemical treatment of water. Recommendations for future action at household, community and city level are made.

Interpreting the impact of flood forecasts by combining policy analysis studies and flood defence

Directory of Open Access Journals (Sweden)

Slomp Robert

2016-01-01

Rijkswaterstaat. Other organisations use these forecasts to define the consequences of the forecast, to take measures (as the evacuation of camping places on rivers banks or lake shores or to estimate the conditional probability of failure of a flood defence. Increasing the resilience of the population by disseminating information from both policy studies (flood scenarios and flood forecasts has been the project goal of the MEGO project “Module Evacuatie Grote Overstromingen”, an information tool for large scale evacuation due to floods. This information is available on a national website. The MEGO project has focussed on making the information from two major policy studies on flood risk available, the first sturdy determined new risk-based standards for flood defences (WV21. The second study determined the current flood risk (VNK-2. The MEGO database contains a selection of verified flood scenario’s. For each scenario the hydraulic loads which will cause a flood are known as are the probabilities of flooding and predicted casualties and damages. Overland flow maps are available. MEGO combines this data with the flood forecast, open data of the “Cadastre” (national Registry, the national digital terrain model (AHN and the main infrastructure (local, regional and national. The site offers prepared and real time maps for professionals during a crisis, and tools to increase risk awareness for citizens. The software was recently renamed national water and flood information system, “Landelijk Informatiesysteem Water en Overstromingen (LIWO ’ when it went live in 2016. In LIWO the second goal of MEGO was realized, by adding the information from flood forecasts. It is an open source model.

44 CFR 65.5 - Revision to special hazard area boundaries with no change to base flood elevation determinations.

Science.gov (United States)

2010-10-01

... zones and floodways) it may be feasible to elevate areas with engineered earthen fill above the base... area boundaries with no change to base flood elevation determinations. 65.5 Section 65.5 Emergency... § 65.5 Revision to special hazard area boundaries with no change to base flood elevation determinations...

Field demonstration of foam injection to confine a chlorinated solvent source zone.

Science.gov (United States)

Portois, Clément; Essouayed, Elyess; Annable, Michael D; Guiserix, Nathalie; Joubert, Antoine; Atteia, Olivier

2018-05-01

A novel approach using foam to manage hazardous waste was successfully demonstrated under active site conditions. The purpose of the foam was to divert groundwater flow, that would normally enter the source zone area, to reduce dissolved contaminant release to the aquifer. During the demonstration, foam was pre generated and directly injected surrounding the chlorinated solvent source zone. Despite the constraints related to the industrial activities and non-optimal position of the injection points, the applicability and effectiveness of the approach have been highlighted using multiple metrics. A combination of measurements and modelling allowed definition of the foam extent surrounding each injection point, and this appears to be the critical metric to define the success of the foam injection approach. Information on the transport of chlorinated solvents in groundwater showed a decrease of contaminant flux by a factor of 4.4 downstream of the confined area. The effective permeability reduction was maintained over a period of three months. The successful containment provides evidence for consideration of the use of foam to improve traditional flushing techniques, by increasing the targeting of contaminants by remedial agents. Copyright © 2018 Elsevier B.V. All rights reserved.

ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann; Riis, Charlotte; Christensen, Anders G.

2012-01-01

Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first...

Determining the Financial Impact of Flood Hazards in Ungaged Basins

Science.gov (United States)

Cotterman, K. A.; Gutenson, J. L.; Pradhan, N. R.; Byrd, A.

2017-12-01

Many portions of the Earth lack adequate authoritative or in situ data that is of great value in determining natural hazard vulnerability from both anthropogenic and physical perspective. Such locations include the majority of developing nations, which do not possess adequate warning systems and protective infrastructure. The lack of warning and protection from natural hazards make these nations vulnerable to the destructive power of events such as floods. The goal of this research is to demonstrate an initial workflow with which to characterize flood financial hazards with global datasets and crowd-sourced, non-authoritative data in ungagged river basins. This workflow includes the hydrologic and hydraulic response of the watershed to precipitation, characterized by the physics-based modeling application Gridded Surface-Subsurface Hydrologic Analysis (GSSHA) model. In addition, data infrastructure and resources are available to approximate the human impact of flooding. Open source, volunteer geographic information (VGI) data can provide global coverage of elements at risk of flooding. Additional valuation mechanisms can then translate flood exposure into percentage and financial damage to each building. The combinations of these tools allow the authors to remotely assess flood hazards with minimal computational, temporal, and financial overhead. This combination of deterministic and stochastic modeling provides the means to quickly characterize watershed flood vulnerability and will allow emergency responders and planners to better understand the implications of flooding, both spatially and financially. In either a planning, real-time, or forecasting scenario, the system will assist the user in understanding basin flood vulnerability and increasing community resiliency and preparedness.

Predicting geomorphically-induced flood risk for the Nepalese Terai communities

Science.gov (United States)

Dingle, Elizabeth; Creed, Maggie; Attal, Mikael; Sinclair, Hugh; Mudd, Simon; Borthwick, Alistair; Dugar, Sumit; Brown, Sarah

2017-04-01

Rivers sourced from the Himalaya irrigate the Indo-Gangetic Plain via major river networks that support 10% of the global population. However, many of these rivers are also the source of devastating floods. During the 2014 Karnali River floods in west Nepal, the Karnali rose to around 16 m at Chisapani (where it enters the Indo-Gangetic Plain), 1 m higher than the previous record in 1983; the return interval for this event was estimated to be 1000 years. Flood risk may currently be underestimated in this region, primarily because changes to the channel bed are not included when identifying areas at risk of flooding from events of varying recurrence intervals. Our observations in the field, corroborated by satellite imagery, show that river beds are highly mobile and constantly evolve through each monsoon. Increased bed levels due to sediment aggradation decreases the capacity of the river, increasing significantly the risk of devastating flood events; we refer to these as 'geomorphically-induced floods'. Major, short-lived episodes of sediment accumulation in channels are caused by stochastic variability in sediment flux generated by storms, earthquakes and glacial outburst floods from upstream parts of the catchment. Here, we generate a field-calibrated, geomorphic flood risk model for varying upstream scenarios, and predict changing flood risk for the Karnali River. A numerical model is used to carry out a sensitivity analysis of changes in channel geometry (particularly aggradation or degradation) based on realistic flood scenarios. In these scenarios, water and sediment discharge are varied within a range of plausible values, up to extreme sediment and water fluxes caused by widespread landsliding and/or intense monsoon precipitation based on existing records. The results of this sensitivity analysis will be used to inform flood hazard maps of the Karnali River floodplain and assess the vulnerability of the populations in the region.

A relative vulnerability estimation of flood disaster using data envelopment analysis in the Dongting Lake region of Hunan

Science.gov (United States)

Li, C.-H.; Li, N.; Wu, L.-C.; Hu, A.-J.

2013-07-01

The vulnerability to flood disaster is addressed by a number of studies. It is of great importance to analyze the vulnerability of different regions and various periods to enable the government to make policies for distributing relief funds and help the regions to improve their capabilities against disasters, yet a recognized paradigm for such studies seems missing. Vulnerability is defined and evaluated through either physical or economic-ecological perspectives depending on the field of the researcher concerned. The vulnerability, however, is the core of both systems as it entails systematic descriptions of flood severities or disaster management units. The research mentioned often has a development perspective, and in this article we decompose the overall flood system into several factors: disaster driver, disaster environment, disaster bearer, and disaster intensity, and take the interaction mechanism among all factors as an indispensable function. The conditions of flood disaster components are demonstrated with disaster driver risk level, disaster environment stability level and disaster bearer sensitivity, respectively. The flood system vulnerability is expressed as vulnerability = f(risk, stability, sensitivity). Based on the theory, data envelopment analysis method (DEA) is used to detail the relative vulnerability's spatiotemporal variation of a flood disaster system and its components in the Dongting Lake region. The study finds that although a flood disaster system's relative vulnerability is closely associated with its components' conditions, the flood system and its components have a different vulnerability level. The overall vulnerability is not the aggregation of its components' vulnerability. On a spatial scale, zones central and adjacent to Dongting Lake and/or river zones are characterized with very high vulnerability. Zones with low and very low vulnerability are mainly distributed in the periphery of the Dongting Lake region. On a temporal

Nested 1D-2D approach for urban surface flood modeling

Science.gov (United States)

Murla, Damian; Willems, Patrick

2015-04-01

Floods in urban areas as a consequence of sewer capacity exceedance receive increased attention because of trends in urbanization (increased population density and impermeability of the surface) and climate change. Despite the strong recent developments in numerical modeling of water systems, urban surface flood modeling is still a major challenge. Whereas very advanced and accurate flood modeling systems are in place and operation by many river authorities in support of flood management along rivers, this is not yet the case in urban water management. Reasons include the small scale of the urban inundation processes, the need to have very high resolution topographical information available, and the huge computational demands. Urban drainage related inundation modeling requires a 1D full hydrodynamic model of the sewer network to be coupled with a 2D surface flood model. To reduce the computational times, 0D (flood cones), 1D/quasi-2D surface flood modeling approaches have been developed and applied in some case studies. In this research, a nested 1D/2D hydraulic model has been developed for an urban catchment at the city of Gent (Belgium), linking the underground sewer (minor system) with the overland surface (major system). For the overland surface flood modelling, comparison was made of 0D, 1D/quasi-2D and full 2D approaches. The approaches are advanced by considering nested 1D-2D approaches, including infiltration in the green city areas, and allowing the effects of surface storm water storage to be simulated. An optimal nested combination of three different mesh resolutions was identified; based on a compromise between precision and simulation time for further real-time flood forecasting, warning and control applications. Main streets as mesh zones together with buildings as void regions constitute one of these mesh resolution (3.75m2 - 15m2); they have been included since they channel most of the flood water from the manholes and they improve the accuracy of

Flood protection structure detection with Lidar: examples on French Mediterranean rivers and coastal areas

Directory of Open Access Journals (Sweden)

Trmal Céline

2016-01-01

Full Text Available This paper aims at presenting different topographic analysis conducted with GIS software in order to detect flood protection structures, natural or artificial, in river floodplains but also in coastal zones. Those computations are relevant because of the availability of high-resolution lidar digital terrain model (DTM. An automatic detection permits to map the footprint of those structures. Then detailed mapping of structure crest is achieved by implementing a least cost path analysis on DTM but also on other terrain aspects such as the curvature. On coastal zones, the analysis is going further by identifying flood protected areas and the level of protection regarding sea level. This article is illustrated by examples on French Mediterranean rivers and coastal areas.

Spatial Analysis of Land Subsidence and Flood Pattern Based on DInSAR Method in Sentinel Sar Imagery and Weighting Method in Geo-Hazard Parameters Combination in North Jakarta Region

Science.gov (United States)

Prasetyo, Y.; Yuwono, B. D.; Ramadhanis, Z.

2018-02-01

The reclamation program carried out in most cities in North Jakarta is directly adjacent to the Jakarta Bay. Beside this program, the density of population and development center in North Jakarta office has increased the need for underground water excessively. As a result of these things, land subsidence in North Jakarta area is relatively high and so intense. The research methodology was developed based on the method of remote sensing and geographic information systems, expected to describe the spatial correlation between the land subsidence and flood phenomenon in North Jakarta. The DInSAR (Differential Interferometric Synthetic Aperture Radar) method with satellite image data Radar (SAR Sentinel 1A) for the years 2015 to 2016 acquisitions was used in this research. It is intended to obtain a pattern of land subsidence in North Jakarta and then combined with flood patterns. For the preparation of flood threat zoning pattern, this research has been modeling in spatial technique based on a weighted parameter of rainfall, elevation, flood zones and land use. In the final result, we have obtained a flood hazard zonation models then do the overlap against DInSAR processing results. As a result of the research, Geo-hazard modelling has a variety results as: 81% of flood threat zones consist of rural area, 12% consists of un-built areas and 7% consists of water areas. Furthermore, the correlation of land subsidence to flood risk zone is divided into three levels of suitability with 74% in high class, 22% in medium class and 4% in low class. For the result of spatial correlation area between land subsidence and flood risk zone are 77% detected in rural area, 17% detected in un-built area and 6% detected in a water area. Whereas the research product is the geo-hazard maps in North Jakarta as the basis of the spatial correlation analysis between the land subsidence and flooding phenomena.double point.

Analysis of external flooding events occurred in foreign nuclear power plant sites

International Nuclear Information System (INIS)

Li Dan; Cai Hankun; Xiao Zhi; An Hongzhen; Mao Huan

2013-01-01

This paper screens and studies 17 external flooding events occurred in foreign NPP sites, analysis the characteristic of external flooding events based on the source of the flooding, the impact on the building, systems and equipment, as well as the threat to nuclear safety. Furthermore, based on the experiences and lessons learned from Fukushima nuclear accident relating to external flooding and countermeasures carried out in the world, some suggestions are proposed in order to improve external flooding response capacity for Chinese NPPs. (authors)

pH control for enhanced reductive bioremediation of chlorinated solvent source zones

Energy Technology Data Exchange (ETDEWEB)

Robinson, Clare, E-mail: clare.robinson@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Barry, D.A., E-mail: andrew.barry@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); McCarty, Perry L., E-mail: pmccarty@stanford.edu [Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020 (United States); Gerhard, Jason I., E-mail: j.gerhard@ed.ac.uk [Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom); Kouznetsova, Irina, E-mail: irina.kouznetsova@ed.ac.uk [Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom)

2009-08-01

Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

Influence of transient flooding on methane fluxes from subtropical pastures

Science.gov (United States)

Seasonally flooded subtropical pastures are major methane (CH4) sources, where transient flooding drives episodic and high-magnitude emissions from the underlying landscape. Understanding the mechanisms that drive these patterns is needed to better understand pasture CH4 emissions and their response...

MAXIMUM RUNOFF OF THE FLOOD ON WADIS OF NORTHERN ...

African Journals Online (AJOL)

lanez

The technique of account the maximal runoff of flood for the rivers of northern part of Algeria based on the theory of ... north to south: 1) coastal Tel – fertile, high cultivated and sown zone; 2) territory of Atlas. Mountains ... In the first case the empiric dependence between maximum intensity of precipitation for some calculation ...

Source zone remediation by ZVI-clay soil-mixing: Reduction of tetrachloroethene mass and mass discharge at a Danish DNAPL site

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Binning, Philip John

2012-01-01

The presence of chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality. The remediation of Dense Non-Aqueous Phase Liquid (DNAPL) sites is especially challenging and the development of innovative remediation technologies is needed. Zero-valent iron (ZVI......) technologies have proven effective for remediation of chlorinated compounds. ZVI-Clay soil-mixing is a new remediation technology, which combines abiotic degradation (via ZVI addition) and immobilization (via soil-mixing and clay addition), whereby a great potential for reduction of both contaminant mass....... The concentrations of chlorinated ethenes were monitored via soil sampling at the source zone and groundwater sampling at a control plane with multilevel samplers covering the entire contaminated plume down-gradient (3 m) of the source zone. The results showed a significant mass depletion of PCE (2-3 orders...

Flood hazard assessment in areas prone to flash flooding

Science.gov (United States)

Kvočka, Davor; Falconer, Roger A.; Bray, Michaela

2016-04-01

Contemporary climate projections suggest that there will be an increase in the occurrence of high-intensity rainfall events in the future. These precipitation extremes are usually the main cause for the emergence of extreme flooding, such as flash flooding. Flash floods are among the most unpredictable, violent and fatal natural hazards in the world. Furthermore, it is expected that flash flooding will occur even more frequently in the future due to more frequent development of extreme weather events, which will greatly increase the danger to people caused by flash flooding. This being the case, there will be a need for high resolution flood hazard maps in areas susceptible to flash flooding. This study investigates what type of flood hazard assessment methods should be used for assessing the flood hazard to people caused by flash flooding. Two different types of flood hazard assessment methods were tested: (i) a widely used method based on an empirical analysis, and (ii) a new, physically based and experimentally calibrated method. Two flash flood events were considered herein, namely: the 2004 Boscastle flash flood and the 2007 Železniki flash flood. The results obtained in this study suggest that in the areas susceptible to extreme flooding, the flood hazard assessment should be conducted using methods based on a mechanics-based analysis. In comparison to standard flood hazard assessment methods, these physically based methods: (i) take into account all of the physical forces, which act on a human body in floodwater, (ii) successfully adapt to abrupt changes in the flow regime, which often occur for flash flood events, and (iii) rapidly assess a flood hazard index in a relatively short period of time.

Assimilation of flood extent data with 2D flood inundation models for localised intense rainfall events

Science.gov (United States)

Neal, J. C.; Wood, M.; Bermúdez, M.; Hostache, R.; Freer, J. E.; Bates, P. D.; Coxon, G.

2017-12-01

Remote sensing of flood inundation extent has long been a potential source of data for constraining and correcting simulations of floodplain inundation. Hydrodynamic models and the computing resources to run them have developed to the extent that simulation of flood inundation in two-dimensional space is now feasible over large river basins in near real-time. However, despite substantial evidence that there is useful information content within inundation extent data, even from low resolution SAR such as that gathered by Envisat ASAR in wide swath mode, making use of the information in a data assimilation system has proved difficult. He we review recent applications of the Ensemble Kalman Filter (EnKF) and Particle Filter for assimilating SAR data, with a focus on the River Severn UK and compare these with complementary research that has looked at the internal error sources and boundary condition errors using detailed terrestrial data that is not available in most locations. Previous applications of the EnKF to this reach have focused on upstream boundary conditions as the source of flow error, however this description of errors was too simplistic for the simulation of summer flood events where localised intense rainfall can be substantial. Therefore, we evaluate the introduction of uncertain lateral inflows to the ensemble. A further limitation of the existing EnKF based methods is the need to convert flood extent to water surface elevations by intersecting the shoreline location with a high quality digital elevation model (e.g. LiDAR). To simplify this data processing step, we evaluate a method to directly assimilate inundation extent as a EnKF model state rather than assimilating water heights, potentially allowing the scheme to be used where high-quality terrain data are sparse.

Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods

Directory of Open Access Journals (Sweden)

Xiaopeng Jia

2014-01-01

Full Text Available The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

Element geochemical analysis of the contribution of aeolian sand to suspended sediment in desert stream flash floods.

Science.gov (United States)

Jia, Xiaopeng; Wang, Haibing

2014-01-01

The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

Efficient use of N-Fertilizers under flooded and un flooded conditions using N-15

International Nuclear Information System (INIS)

Ismail, M.M.A.

1997-01-01

Laboratory and greenhouse experiments were out to study the behaviour of nitrogen fertilizers in soil and efficiency for plant under flooded and un flooded conditions using 15 N-labelled urea as a source of N and many possibilities such as urease and nitrification inhibitors and some of slow-release N-fertilizers. The obtained results can be summarized under the following headings: A) Greenhouse Experiments: 1- Effect of nitrogen rats, methods of N-application and nitrification inhibitors or slow- release N-fertilizer on wheat plants. 2- The combined effect of organic materials and inorganic nitrogen fertilizer at different levels on rice yield. 3- Effect of some urease inhibitors and slow-release fertilizer on the efficiency of urea applied to rice. B) Laboratory experiment. 4- Effect of urease and/or nitrification inhibitors on urea hydrolysis and transformation under flooded soil conditions. 20 tabs., 17 figs., 228 refs

Natural hazards on alluvial fans: the debris flow and flash flood disaster of December 1999, Vargas state, Venezuela

Science.gov (United States)

Larsen, Matthew C.; Wieczorek, Gerald F.; Eaton, L.S.; Torres-Sierra, Heriberto; Sylva, Walter F.

2001-01-01

Large populations live on or near alluvial fans in locations such as Los Angeles, California, Salt Lake City, Utah, Denver, Colorado, and lesser known areas such as Sarno, Italy, and Vargas, Venezuela. Debris flows and flash floods occur episodically in these alluvial fan environments, and place many communities at high risk during intense and prolonged rainfall. In December 1999, rainstorms induced thousands of landslides along the Cordillera de la Costa, Vargas, Venezuela. Rainfall accumulation of 293 mm during the first 2 weeks of December was followed by an additional 911 mm of rainfall on December 14 through 16. Debris flows and floods inundated coastal communities resulting in a catastrophic death toll of as many as 30,000 people. Flash floods and debris flows caused severe property destruction on alluvial fans at the mouths of the coastal mountain drainage network. In time scales spanning thousands of years, the alluvial fans along this Caribbean coastline are dynamic zones of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise abruptly from the Caribbean Sea, the alluvial fans provide practically the only flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. KEY TERMS: Debris flows, flash floods, alluvial fans, natural hazards, landslides, Venezuela

Development of high-resolution multi-scale modelling system for simulation of coastal-fluvial urban flooding

Science.gov (United States)

Comer, Joanne; Indiana Olbert, Agnieszka; Nash, Stephen; Hartnett, Michael

2017-02-01

Urban developments in coastal zones are often exposed to natural hazards such as flooding. In this research, a state-of-the-art, multi-scale nested flood (MSN_Flood) model is applied to simulate complex coastal-fluvial urban flooding due to combined effects of tides, surges and river discharges. Cork city on Ireland's southwest coast is a study case. The flood modelling system comprises a cascade of four dynamically linked models that resolve the hydrodynamics of Cork Harbour and/or its sub-region at four scales: 90, 30, 6 and 2 m. Results demonstrate that the internalization of the nested boundary through the use of ghost cells combined with a tailored adaptive interpolation technique creates a highly dynamic moving boundary that permits flooding and drying of the nested boundary. This novel feature of MSN_Flood provides a high degree of choice regarding the location of the boundaries to the nested domain and therefore flexibility in model application. The nested MSN_Flood model through dynamic downscaling facilitates significant improvements in accuracy of model output without incurring the computational expense of high spatial resolution over the entire model domain. The urban flood model provides full characteristics of water levels and flow regimes necessary for flood hazard identification and flood risk assessment.

A physically-based parsimonious hydrological model for flash floods in Mediterranean catchments

Directory of Open Access Journals (Sweden)

H. Roux

2011-09-01

Full Text Available A spatially distributed hydrological model, dedicated to flood simulation, is developed on the basis of physical process representation (infiltration, overland flow, channel routing. Estimation of model parameters requires data concerning topography, soil properties, vegetation and land use. Four parameters are calibrated for the entire catchment using one flood event. Model sensitivity to individual parameters is assessed using Monte-Carlo simulations. Results of this sensitivity analysis with a criterion based on the Nash efficiency coefficient and the error of peak time and runoff are used to calibrate the model. This procedure is tested on the Gardon d'Anduze catchment, located in the Mediterranean zone of southern France. A first validation is conducted using three flood events with different hydrometeorological characteristics. This sensitivity analysis along with validation tests illustrates the predictive capability of the model and points out the possible improvements on the model's structure and parameterization for flash flood forecasting, especially in ungauged basins. Concerning the model structure, results show that water transfer through the subsurface zone also contributes to the hydrograph response to an extreme event, especially during the recession period. Maps of soil saturation emphasize the impact of rainfall and soil properties variability on these dynamics. Adding a subsurface flow component in the simulation also greatly impacts the spatial distribution of soil saturation and shows the importance of the drainage network. Measures of such distributed variables would help discriminating between different possible model structures.

A Review on Flood Events for Kelantan River Watershed in Malaysia for Last Decade (2001-2010)

Science.gov (United States)

Aminah Shakirah, J.; Sidek, L. M.; Hidayah, B.; Nazirul, M. Z.; Jajarmizadeh, M.; Ros, F. C.; Roseli, ZA

2016-03-01

Malaysia is located at tropical zone and high precipitation area that frequently hit by flood events when it is near monsoon season. This hydro hazard has been one of the main concerns for governmental and non-governmental sectors. High floods lead in financial damages and they are related with human’s life. Kelantan watershed is one of the challenging watersheds which mostly suffer from flood events and heavy rainfall events. Flood in Kelantan watershed is related with monetary misfortunes and lives. Clearly, flood have significant influence on various water sectors such water supply, agriculture, human health and ecosystems therefore study of this topic and presentation of available of any data and information can be a valuable baseline for upcoming research in vulnerable case studies. In this study, Kelantan watershed is selected because it is prone to flooding and urban areas classified as vulnerable districts. This overview is discussed on the last decade (2001-2010) floods events in Kelantan.

Hydrological and hydraulic models for determination of flood-prone and flood inundation areas

Science.gov (United States)

Aksoy, Hafzullah; Sadan Ozgur Kirca, Veysel; Burgan, Halil Ibrahim; Kellecioglu, Dorukhan

2016-05-01

Geographic Information Systems (GIS) are widely used in most studies on water resources. Especially, when the topography and geomorphology of study area are considered, GIS can ease the work load. Detailed data should be used in this kind of studies. Because of, either the complication of the models or the requirement of highly detailed data, model outputs can be obtained fast only with a good optimization. The aim in this study, firstly, is to determine flood-prone areas in a watershed by using a hydrological model considering two wetness indexes; the topographical wetness index, and the SAGA (System for Automated Geoscientific Analyses) wetness index. The wetness indexes were obtained in the Quantum GIS (QGIS) software by using the Digital Elevation Model of the study area. Flood-prone areas are determined by considering the wetness index maps of the watershed. As the second stage of this study, a hydraulic model, HEC-RAS, was executed to determine flood inundation areas under different return period-flood events. River network cross-sections required for this study were derived from highly detailed digital elevation models by QGIS. Also river hydraulic parameters were used in the hydraulic model. Modelling technology used in this study is made of freely available open source softwares. Based on case studies performed on watersheds in Turkey, it is concluded that results of such studies can be used for taking precaution measures against life and monetary losses due to floods in urban areas particularly.

Hydrological and hydraulic models for determination of flood-prone and flood inundation areas

Directory of Open Access Journals (Sweden)

H. Aksoy

2016-05-01

Full Text Available Geographic Information Systems (GIS are widely used in most studies on water resources. Especially, when the topography and geomorphology of study area are considered, GIS can ease the work load. Detailed data should be used in this kind of studies. Because of, either the complication of the models or the requirement of highly detailed data, model outputs can be obtained fast only with a good optimization. The aim in this study, firstly, is to determine flood-prone areas in a watershed by using a hydrological model considering two wetness indexes; the topographical wetness index, and the SAGA (System for Automated Geoscientific Analyses wetness index. The wetness indexes were obtained in the Quantum GIS (QGIS software by using the Digital Elevation Model of the study area. Flood-prone areas are determined by considering the wetness index maps of the watershed. As the second stage of this study, a hydraulic model, HEC-RAS, was executed to determine flood inundation areas under different return period-flood events. River network cross-sections required for this study were derived from highly detailed digital elevation models by QGIS. Also river hydraulic parameters were used in the hydraulic model. Modelling technology used in this study is made of freely available open source softwares. Based on case studies performed on watersheds in Turkey, it is concluded that results of such studies can be used for taking precaution measures against life and monetary losses due to floods in urban areas particularly.

Localization of epileptogenic zones in Lennox–Gastaut syndrome using frequency domain source imaging of intracranial electroencephalography: a preliminary investigation

International Nuclear Information System (INIS)

Cho, Jae-Hyun; Jung, Young-Jin; Kim, Jeong-Youn; Im, Chang-Hwan; Kang, Hoon-Chul; Kim, Heung Dong; Yoon, Dae Sung; Lee, Yong-Ho

2013-01-01

Although intracranial electroencephalography (iEEG) has been widely used to localize epileptogenic zones in epilepsy, visual inspection of iEEG recordings does not always result in a favorable surgical outcome, especially in secondary generalized epilepsy such as Lennox–Gastaut syndrome (LGS). Various computational iEEG analysis methods have recently been introduced to confirm the visual inspection results. Of these methods, high gamma oscillation in iEEG has attracted interest because a series of studies have reported a close relationship between epileptogenic zones and cortical areas with high gamma oscillation. Meanwhile, frequency domain source imaging of EEG and MEG oscillations has proven to be a useful auxiliary tool for identifying rough locations of epileptogenic zones. To the best of our knowledge, however, frequency domain source imaging of high gamma iEEG oscillations has not been studied. In this study, we investigated whether the iEEG-based frequency domain source imaging of high gamma oscillation (60–100 Hz) would be a useful supplementary tool for identifying epileptogenic zones in patients with secondary generalized epilepsy. The method was applied to three successfully operated on LGS patients, whose iEEG contained some ictal events with distinct high gamma oscillations before seizure onset. The resultant cortical source distributions were compared with surgical resection areas and with high gamma spectral power distributions on the intracranial sensor plane. While the results of the sensor-level analyses contained many spurious activities, the results of frequency domain source imaging coincided better with the surgical resection areas, suggesting that the frequency domain source imaging of iEEG high gamma oscillations might help enhance the accuracy of pre-surgical evaluations of patients with secondary generalized epilepsy. (paper)

The source and longevity of sulfur in an Icelandic flood basalt eruption plume

Science.gov (United States)

Ilyinskaya, Evgenia; Edmonds, Marie; Mather, Tamsin; Schmidt, Anja; Hartley, Margaret; Oppenheimer, Clive; Pope, Francis; Donovan, Amy; Sigmarsson, Olgeir; Maclennan, John; Shorttle, Oliver; Francis, Peter; Bergsson, Baldur; Barsotti, Sara; Thordarson, Thorvaldur; Bali, Eniko; Keller, Nicole; Stefansson, Andri

2015-04-01

The Holuhraun fissure eruption (Bárðarbunga volcanic system, central Iceland) has been ongoing since 31 August 2014 and is now the largest in Europe since the 1783-84 Laki event. For the first time in the modern age we have the opportunity to study at first hand the environmental impact of a flood basalt fissure eruption (>1 km3 lava). Flood basalt eruptions are one of the most hazardous volcanic scenarios in Iceland and have had enormous societal and economic consequences across the northern hemisphere in the past. The Laki eruption caused the deaths of >20% of the Icelandic population by environmental pollution and famine and potentially also increased European levels of mortality through air pollution by sulphur-bearing gas and aerosol. A flood basalt eruption was included in the UK National Risk Register in 2012 as one of the highest priority risks. The gas emissions from Holuhraun have been sustained since its beginning, repeatedly causing severe air pollution in populated areas in Iceland. During 18-22 September, SO2 fluxes reached 45 kt/day, a rate of outgassing rarely observed during sustained eruptions, suggesting that the sulfur loading per kg of erupted magma exceeds both that of other recent eruptions in Iceland and perhaps also other historic basaltic eruptions globally. This raises key questions regarding the origin of these prodigious quantities of sulphur. A lack of understanding of the source of this sulfur, the conversion rates of SO2 gas into aerosol, the residence times of aerosol in the plume and the dependence of these on meteorological factors is limiting our confidence in the ability of atmospheric models to forecast gas and aerosol concentrations in the near- and far-field from Icelandic flood basalt eruptions. In 2015 our group is undertaking a project funded by UK NERC urgency scheme to investigate several aspects of the sulfur budget at Holuhraun using a novel and powerful approach involving simultaneous tracking of sulfur and

FLOOD SUSCEPTIBILITY ASSESSMENT IN THE NIRAJ BASIN

Directory of Open Access Journals (Sweden)

SANDA ROŞCA

2012-03-01

Full Text Available Flood susceptibility assessment in the Niraj basin. In the context of global warming and the increasing frequency of extreme weather events, it becomes evident that we have to face natural hazards, such as floods. In the area of Niraj basin this phenomenon is specific both in the spring, because of the snow melting and of the precipitations which come along with the season, and then in the summer because of the torrential precipitations but rarely in autumn and winter. The aim of this paper is to determinate the susceptibility of the zone and obtain a map which will take into consideration the possibility of a flooding. Defining vulnerability can help us understand this type of natural disasters and find the best ways to reduce it. For this purpose we use thematic layers, morphological characteristics (slope and depth fragmentation, hydrological characteristics, geology, pedology (permeability and soil texture, landuse, precipitation data, and human interventions because in this way we have the possibility to use data mining for this purpose. Data mining will allow us to extract new information based on the existing sets of data.The final result will be a thematic map that highlights the areas which are exposed to the flood. Therefore, this map can be used as a support decision for local government or business purposes.

Development of flood index by characterisation of flood hydrographs

Science.gov (United States)

Bhattacharya, Biswa; Suman, Asadusjjaman

2015-04-01

In recent years the world has experienced deaths, large-scale displacement of people, billions of Euros of economic damage, mental stress and ecosystem impacts due to flooding. Global changes (climate change, population and economic growth, and urbanisation) are exacerbating the severity of flooding. The 2010 floods in Pakistan and the 2011 floods in Australia and Thailand demonstrate the need for concerted action in the face of global societal and environmental changes to strengthen resilience against flooding. Due to climatological characteristics there are catchments where flood forecasting may have a relatively limited role and flood event management may have to be trusted upon. For example, in flash flood catchments, which often may be tiny and un-gauged, flood event management often depends on approximate prediction tools such as flash flood guidance (FFG). There are catchments fed largely by flood waters coming from upstream catchments, which are un-gauged or due to data sharing issues in transboundary catchments the flow of information from upstream catchment is limited. Hydrological and hydraulic modelling of these downstream catchments will never be sufficient to provide any required forecasting lead time and alternative tools to support flood event management will be required. In FFG, or similar approaches, the primary motif is to provide guidance by synthesising the historical data. We follow a similar approach to characterise past flood hydrographs to determine a flood index (FI), which varies in space and time with flood magnitude and its propagation. By studying the variation of the index the pockets of high flood risk, requiring attention, can be earmarked beforehand. This approach can be very useful in flood risk management of catchments where information about hydro-meteorological variables is inadequate for any forecasting system. This paper presents the development of FI and its application to several catchments including in Kentucky in the USA

Uncertainty quantification in flood risk assessment

Science.gov (United States)

Blöschl, Günter; Hall, Julia; Kiss, Andrea; Parajka, Juraj; Perdigão, Rui A. P.; Rogger, Magdalena; Salinas, José Luis; Viglione, Alberto

2017-04-01

Uncertainty is inherent to flood risk assessments because of the complexity of the human-water system, which is characterised by nonlinearities and interdependencies, because of limited knowledge about system properties and because of cognitive biases in human perception and decision-making. On top of the uncertainty associated with the assessment of the existing risk to extreme events, additional uncertainty arises because of temporal changes in the system due to climate change, modifications of the environment, population growth and the associated increase in assets. Novel risk assessment concepts are needed that take into account all these sources of uncertainty. They should be based on the understanding of how flood extremes are generated and how they change over time. They should also account for the dynamics of risk perception of decision makers and population in the floodplains. In this talk we discuss these novel risk assessment concepts through examples from Flood Frequency Hydrology, Socio-Hydrology and Predictions Under Change. We believe that uncertainty quantification in flood risk assessment should lead to a robust approach of integrated flood risk management aiming at enhancing resilience rather than searching for optimal defense strategies.

Hydrogeomorphic Investigation of the 2015 Atacama Floods, Northern Chile

Science.gov (United States)

Wilcox, A. C.; Escauriaza, C. R.; Agredano, R., Jr.; Mignot, E.; Gironas, J. A.; Cienfuegos, R.; Mao, L.

2015-12-01

In March 2015 unusual atmospheric conditions over the Atacama Desert of northern Chile, the driest area on Earth outside of Antarctica, produced many years worth of rainfall in a 24-hour period. The resulting sediment-rich floods caused dozens of deaths and/or disappearances, over $1 billion in estimated damage, and widespread geomorphic change. Here we describe the hydrologic and geomorphic drivers and responses to the 2015 Atacama floods, including characterization of the hydrologic forcing, water and sediment routing from source areas in the upper watershed to the outlet at the Pacific Ocean, and urban flooding impacts of this event. In a region where few direct measurements of precipitation and discharge during these events are available, we combined hydrologic and hydraulic modeling with field and aerial photograph interpretation of sediment sources and geomorphic change. A remarkable element of the flood, particularly with respect to its effects on urban areas, was its high sediment load. Despite widespread hillslope erosion in the form of rilling and gullying initiated by overland flow, sediment from these sources typically did not reach valley bottoms, and only limited, small-scale mass wasting was observed. Field observations indicated that the sediment load was primarily derived from dramatic erosion of channel bed, bank, and floodplain material (i.e., valley fill). In the coastal city of Chañaral, flooding of the Salado River produced maximum water depths over 6 m, meters-thick mud deposition in buildings and along city streets, flow velocities larger than 8 m/s, and coastal erosion. Broader implications of studying the Atacama flooding include hazard reduction, the history of copper mining and more than five decades of contamination in many of the affected watersheds, and the Atacama's status as a terrestrial analog for Mars.

Flood mapping with multitemporal MODIS data

Science.gov (United States)

Son, Nguyen-Thanh; Chen, Chi-Farn; Chen, Cheng-Ru

2014-05-01

Flood is one of the most devastating and frequent disasters resulting in loss of human life and serve damage to infrastructure and agricultural production. Flood is phenomenal in the Mekong River Delta (MRD), Vietnam. It annually lasts from July to November. Information on spatiotemporal flood dynamics is thus important for planners to devise successful strategies for flood monitoring and mitigation of its negative effects. The main objective of this study is to develop an approach for weekly mapping flood dynamics with the Moderate Resolution Imaging Spectroradiometer data in MRD using the water fraction model (WFM). The data processed for 2009 comprises three main steps: (1) data pre-processing to construct smooth time series of the difference in the values (DVLE) between land surface water index (LSWI) and enhanced vegetation index (EVI) using the empirical mode decomposition (EMD), (2) flood derivation using WFM, and (3) accuracy assessment. The mapping results were compared with the ground reference data, which were constructed from Envisat Advanced Synthetic Aperture Radar (ASAR) data. As several error sources, including mixed-pixel problems and low-resolution bias between the mapping results and ground reference data, could lower the level of classification accuracy, the comparisons indicated satisfactory results with the overall accuracy of 80.5% and Kappa coefficient of 0.61, respectively. These results were reaffirmed by a close correlation between the MODIS-derived flood area and that of the ground reference map at the provincial level, with the correlation coefficients (R2) of 0.93. Considering the importance of remote sensing for monitoring floods and mitigating the damage caused by floods to crops and infrastructure, this study eventually leads to the realization of the value of using time-series MODIS DVLE data for weekly flood monitoring in MRD with the aid of EMD and WFM. Such an approach that could provide quantitative information on

Temporal clustering of floods in Germany: Do flood-rich and flood-poor periods exist?

Science.gov (United States)

Merz, Bruno; Nguyen, Viet Dung; Vorogushyn, Sergiy

2016-10-01

The repeated occurrence of exceptional floods within a few years, such as the Rhine floods in 1993 and 1995 and the Elbe and Danube floods in 2002 and 2013, suggests that floods in Central Europe may be organized in flood-rich and flood-poor periods. This hypothesis is studied by testing the significance of temporal clustering in flood occurrence (peak-over-threshold) time series for 68 catchments across Germany for the period 1932-2005. To assess the robustness of the results, different methods are used: Firstly, the index of dispersion, which quantifies the departure from a homogeneous Poisson process, is investigated. Further, the time-variation of the flood occurrence rate is derived by non-parametric kernel implementation and the significance of clustering is evaluated via parametric and non-parametric tests. Although the methods give consistent overall results, the specific results differ considerably. Hence, we recommend applying different methods when investigating flood clustering. For flood estimation and risk management, it is of relevance to understand whether clustering changes with flood severity and time scale. To this end, clustering is assessed for different thresholds and time scales. It is found that the majority of catchments show temporal clustering at the 5% significance level for low thresholds and time scales of one to a few years. However, clustering decreases substantially with increasing threshold and time scale. We hypothesize that flood clustering in Germany is mainly caused by catchment memory effects along with intra- to inter-annual climate variability, and that decadal climate variability plays a minor role.

Landscape changes as a factor affecting the course and consequences of extreme floods in the Otava river basin, Czech Republic.

Science.gov (United States)

Langhammer, Jakub; Vilímek, Vít

2008-09-01

The paper presents the analysis of anthropogenical modifications of the landscape in relation to the course and consequences of floods. The research was conducted in the Otava river basin which represents the core zone of the extreme flood in August 2002 in Central Europe. The analysis was focused on the key indicators of landscape modification potentially affecting the runoff process - the long-term changes of land-use, changes of land cover structure, land drainage, historical shortening of the river network and the modifications of streams and floodplains. The information on intensity and spatial distribution of modifications was derived from different data sources--historical maps, available GIS data, remote sensing and field mapping. The results revealed a high level of spatial diversity of anthropogenical modifications in different parts of the river basin. The intensive modifications in most of indicators were concentrated in the lowland region of the river basin due to its agricultural use; however important changes were also recorded in the headwater region of the basin. The high spatial diversity of the modifications may result in their varying effect on the course and consequences of floods in different parts of the river basin. This effect is demonstrated by the cluster analysis based on the matrix of indicators of stream and floodplain modification, physiogeographical characteristics and geomorphological evidences of the flood in August 2002, derived from the individual thematic layers using GIS.

Assessing flood forecast uncertainty with fuzzy arithmetic

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de Bruyn Bertrand

2016-01-01

Full Text Available Providing forecasts for flow rates and water levels during floods have to be associated with uncertainty estimates. The forecast sources of uncertainty are plural. For hydrological forecasts (rainfall-runoff performed using a deterministic hydrological model with basic physics, two main sources can be identified. The first obvious source is the forcing data: rainfall forecast data are supplied in real time by meteorological forecasting services to the Flood Forecasting Service within a range between a lowest and a highest predicted discharge. These two values define an uncertainty interval for the rainfall variable provided on a given watershed. The second source of uncertainty is related to the complexity of the modeled system (the catchment impacted by the hydro-meteorological phenomenon, the number of variables that may describe the problem and their spatial and time variability. The model simplifies the system by reducing the number of variables to a few parameters. Thus it contains an intrinsic uncertainty. This model uncertainty is assessed by comparing simulated and observed rates for a large number of hydro-meteorological events. We propose a method based on fuzzy arithmetic to estimate the possible range of flow rates (and levels of water making a forecast based on possible rainfalls provided by forcing and uncertainty model. The model uncertainty is here expressed as a range of possible values. Both rainfall and model uncertainties are combined with fuzzy arithmetic. This method allows to evaluate the prediction uncertainty range. The Flood Forecasting Service of Oise and Aisne rivers, in particular, monitors the upstream watershed of the Oise at Hirson. This watershed’s area is 310 km2. Its response time is about 10 hours. Several hydrological models are calibrated for flood forecasting in this watershed and use the rainfall forecast. This method presents the advantage to be easily implemented. Moreover, it permits to be carried out

Social media for disaster response during floods

Science.gov (United States)

Eilander, D.; van de Vries, C.; Baart, F.; van Swol, R.; Wagemaker, J.; van Loenen, A.

2015-12-01

During floods it is difficult to obtain real-time accurate information about the extent and severity of the hazard. This information is very important for disaster risk reduction management and crisis relief organizations. Currently, real-time information is derived from few sources such as field reports, traffic camera's, satellite images and areal images. However, getting a real-time and accurate picture of the situation on the ground remains difficult. At the same time, people affected by natural hazards increasingly share their observations and their needs through digital media. Unlike conventional monitoring systems, Twitter data contains a relatively large number of real-time ground truth observations representing both physical hazard characteristics and hazard impacts. In the city of Jakarta, Indonesia, the intensity of unique flood related tweets during a flood event, peaked at almost 900 tweets per minute during floods in early 2015. Flood events around the world in 2014/2015 yielded large numbers of flood related tweets: from Philippines (85.000) to Pakistan (82.000) to South-Korea (50.000) to Detroit (20.000). The challenge here is to filter out useful content from this cloud of data, validate these observations and convert them to readily usable information. In Jakarta, flood related tweets often contain information about the flood depth. In a pilot we showed that this type of information can be used for real-time mapping of the flood extent by plotting these observations on a Digital Elevation Model. Uncertainties in the observations were taken into account by assigning a probability to each observation indicating its likelihood to be correct based on statistical analysis of the total population of tweets. The resulting flood maps proved to be correct for about 75% of the neighborhoods in Jakarta. Further cross-validation of flood related tweets against (hydro-) meteorological data is to likely improve the skill of the method.

Assessment of water quality in the elbe river at flood water conditions based on cluster analysis, principle components analysis, and source apportionment

Energy Technology Data Exchange (ETDEWEB)

Baborowski, Martina [Department of River Ecology, UFZ-Helmholtz Centre for Environmental Research, Magdeburg (Germany); Simeonov, Vasil [Faculty of Chemistry, University of Sofia, Sofia (Bulgaria); Einax, Juergen W. [Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University of Jena, Jena (Germany)

2012-04-15

An assessment of water quality measurements during a spring flood in the Elbe River is presented. Daily samples were taken at a site in the middle Elbe, which is part of the network of the International Commission for the Protection of the Elbe River (IKSE/MKOL). Cluster analysis (CA), principal components analysis (PCA), and source apportionment (APCS apportioning) were used to assess the flood-dependent matter transport. As a result, three main components could be extracted as important to the matter transport in the Elbe River basin during flood events: (i) re-suspended contaminated sediments, which led to temporarily increased concentrations of suspended matter and of most of the investigated heavy metals; (ii) water discharge related concentrations of pedogenic dissolved organic matter (DOM) as well as preliminary diluted concentrations of uranium and chloride, parameters with stable pollution background in the river basin; and (iii) abandoned mines, i.e., their dewatering systems, with particular influence on nickel, manganese, and zinc concentrations. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Assessment of water quality in the elbe river at flood water conditions based on cluster analysis, principle components analysis, and source apportionment

International Nuclear Information System (INIS)

Baborowski, Martina; Simeonov, Vasil; Einax, Juergen W.

2012-01-01

An assessment of water quality measurements during a spring flood in the Elbe River is presented. Daily samples were taken at a site in the middle Elbe, which is part of the network of the International Commission for the Protection of the Elbe River (IKSE/MKOL). Cluster analysis (CA), principal components analysis (PCA), and source apportionment (APCS apportioning) were used to assess the flood-dependent matter transport. As a result, three main components could be extracted as important to the matter transport in the Elbe River basin during flood events: (i) re-suspended contaminated sediments, which led to temporarily increased concentrations of suspended matter and of most of the investigated heavy metals; (ii) water discharge related concentrations of pedogenic dissolved organic matter (DOM) as well as preliminary diluted concentrations of uranium and chloride, parameters with stable pollution background in the river basin; and (iii) abandoned mines, i.e., their dewatering systems, with particular influence on nickel, manganese, and zinc concentrations. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Flood hazards in an urbanizing watershed in Riyadh, Saudi Arabia

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Hatim O. Sharif

2016-03-01

Full Text Available Riyadh, the capital of the Kingdom of Saudi Arabia, has experienced unusual levels of urbanization in the past few decades, making it one of the fastest growing cities in the world. This paper examines flood hazards in the rapidly urbanizing catchment of Al-Aysen in Riyadh. Remote sensing and geographic information system techniques were employed to obtain and prepare input data for hydrologic and hydraulic models, with the former based on the very popular curve number approach. Due to the limited nature of the rainfall data, observations from two rain gauges in the vicinity of the catchment were used to estimate design storms. The hydrologic model was run in a semi-distributed mode by dividing the catchment into many sub-catchments. The impact of urbanization on run-off volume and peak discharge resulting from different storms was investigated, with various urbanization scenarios simulated. Flood hazard zones and affected streets were also identified through hydrologic/hydraulic model simulation. The mismatch between administrative and catchment boundaries can create problems in flood risk management for similar cities since hydrologic processes and flood hazards are based on the hydrologic connectivity. Since flooding events impact the road network and create driving hazards, governmental decision-makers must take the necessary precautions to protect drivers in these situations.

Characterization of remarkable floods in France, a transdisciplinary approach applied on generalized floods of January 1910

Science.gov (United States)

Boudou, Martin; Lang, Michel; Vinet, Freddy; Coeur, Denis

2014-05-01

The 2007 Flood Directive promotes the integration and valorization of historical and significant floods in flood risk management (Flood Directive Text, chapter II, and article 4). Taking into account extreme past floods analysis seems necessary in the mitigation process of vulnerability face to flooding risk. In France, this aspect of the Directive was carried out through the elaboration of Preliminary Flood Risk Assessment (PFRA) and the establishment of a 2000 floods list. From this first list, a sample of 176 floods, considered as remarkable has been selected. These floods were compiled in discussion with local authorities in charge of flood management (Lang et al., 2012) and have to be integrated in priority in local risk management policies. However, a consideration emerges about this classification: how a remarkable flood can be defined? According which criteria can it be considered as remarkable? To answer these questions, a methodology has been established by building an evaluation grid of remarkable floods in France. The primary objective of this grid is to analyze the remarkable flood's characteristics (hydrological and meteorological characteristics, sociological- political and economic impacts), and secondly to propose a classification of significant floods selected in the 2011 PFRA. To elaborate this evaluation grid, several issues had to be taken into account. First, the objective is to allow the comparison of events from various periods. These temporal disparities include the integration of various kinds of data and point out the importance of historical hydrology. It is possible to evaluate accurately the characteristics of recent floods by interpreting quantitative data (for example hydrological records. However, for floods that occurred before the 1960's it is necessary resorting to qualitative information such as written sources is necessary (Coeur, Lang, 2008). In a second part the evaluation grid requires equitable criteria in order not to

Modeling Flood Plain Hydrology and Forest Productivity of Congaree Swamp, South Carolina

Science.gov (United States)

Doyle, Thomas W.

2009-01-01

An ecological field and modeling study was conducted to examine the flood relations of backswamp forests and park trails of the flood plain portion of Congaree National Park, S.C. Continuous water level gages were distributed across the length and width of the flood plain portion - referred to as 'Congaree Swamp' - to facilitate understanding of the lag and peak flood coupling with stage of the Congaree River. A severe and prolonged drought at study start in 2001 extended into late 2002 before backswamp zones circulated floodwaters. Water levels were monitored at 10 gaging stations over a 4-year period from 2002 to 2006. Historical water level stage and discharge data from the Congaree River were digitized from published sources and U.S. Geological Survey (USGS) archives to obtain long-term daily averages for an upstream gage at Columbia, S.C., dating back to 1892. Elevation of ground surface was surveyed for all park trails, water level gages, and additional circuits of roads and boundaries. Rectified elevation data were interpolated into a digital elevation model of the park trail system. Regression models were applied to establish time lags and stage relations between gages at Columbia, S.C., and gages in the upper, middle, and lower reaches of the river and backswamp within the park. Flood relations among backswamp gages exhibited different retention and recession behavior between flood plain reaches with greater hydroperiod in the lower reach than those in the upper and middle reaches of the Congaree Swamp. A flood plain inundation model was developed from gage relations to predict critical river stages and potential inundation of hiking trails on a real-time basis and to forecast the 24-hour flood In addition, tree-ring analysis was used to evaluate the effects of flood events and flooding history on forest resources at Congaree National Park. Tree cores were collected from populations of loblolly pine (Pinus taeda), baldcypress (Taxodium distichum), water

THE EFFECT OF THE GEOMETRIC STRUCTURE OF FLOOD PLAIN VEGETATION ON THE PROBABILITY OF PASSING FOR PLANT DEBRIS

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Natalia Walczak

2016-09-01

Full Text Available Flood plains are a specific sedimentary environment. They are a natural clarifier and filter for rivers carrying large amounts of heavy metals, biogenic elements and other contaminants transported during high water and floods. Plenty of it is accumulated in the riverbank zone of channels i.e. a buffer strip. This is a relatively narrow strip of land situated along watercourses, often covered with riparian plants. It is functionally associated with river flooding and it forms a transition zone to ecosystems of mixed (oak-lime-hornbeam forest plants. These plants unquestionably grow into a natural protective system of surface waters against contamination flowing down from areas used for agricultural purposes. Buffer zones provide the opportunity for self-cleaning, and according researchers they are among the most efficient natural tools to protect a catchment area. They can reduce the amount of sediments and nutrients carried by surface water flowing down from agricultural areas. Besides positive effects, the zones are accompanied by the phenomenon of flow blockage, which is particularly hazardous in case of directing great water away from its main channel. Shrubby vegetation retains small elements of plant origin and thus the free flow of water stopped. The article analyses the effect of vegetation structure density on flow conditions for small plant debris on a laboratory scale.

[Relationship between groundwater quality index of nutrition element and organic matter in riparian zone and water quality in river].

Science.gov (United States)

Hua-Shan, Xu; Tong-Qian, Zhao; Hong-Q, Meng; Zong-Xue, Xu; Chao-Hon, Ma

2011-04-01

Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that there will be great risk of nitrogen, phosphorus, nitrate nitrogen and organic matter permeating into the groundwater if floodplain changes into farmland. As the special control unit of nitrogen pollution between rivers and artificial wetlands, dry fanning areas near the river play a very important role in nitrogen migration between river and groundwater. Farm manure as base fertilizer may he an important source of phosphorus leak and loss at the artificial wetlands. Phosphorus leaks into the groundwater and is transferred along the hydraulic gradient, especially during the period of regulation for water and sediment at the Xiaolangdi Reservoir. The land use types and farming systems of the riparian floodplain have a major impact on the nitrate nitrogen contents of the groundwater. Nitrogen can infiltrate and accumulate quickly at anaerobic conditions in the fish pond area, and the annual nitrogen achieves a relatively balanced state in lotus area. In those areas, the soil is flooded and at anaerobic condition in spring and summer, nitrogen infiltrates and denitrification significantly, but soil is not flooded and at aerobic condition in the autumn and winter, and during these time, a significant nitrogen nitrification process occurs. In the area between 50 m and 200 m from the river

Using integrated modeling for generating watershed-scale dynamic flood maps for Hurricane Harvey

Science.gov (United States)

Saksena, S.; Dey, S.; Merwade, V.; Singhofen, P. J.

2017-12-01

Hurricane Harvey, which was categorized as a 1000-year return period event, produced unprecedented rainfall and flooding in Houston. Although the expected rainfall was forecasted much before the event, there was no way to identify which regions were at higher risk of flooding, the magnitude of flooding, and when the impacts of rainfall would be highest. The inability to predict the location, duration, and depth of flooding created uncertainty over evacuation planning and preparation. This catastrophic event highlighted that the conventional approach to managing flood risk using 100-year static flood inundation maps is inadequate because of its inability to predict flood duration and extents for 500-year or 1000-year return period events in real-time. The purpose of this study is to create models that can dynamically predict the impacts of rainfall and subsequent flooding, so that necessary evacuation and rescue efforts can be planned in advance. This study uses a 2D integrated surface water-groundwater model called ICPR (Interconnected Channel and Pond Routing) to simulate both the hydrology and hydrodynamics for Hurricane Harvey. The methodology involves using the NHD stream network to create a 2D model that incorporates rainfall, land use, vadose zone properties and topography to estimate streamflow and generate dynamic flood depths and extents. The results show that dynamic flood mapping captures the flood hydrodynamics more accurately and is able to predict the magnitude, extent and time of occurrence for extreme events such as Hurricane Harvey. Therefore, integrated modeling has the potential to identify regions that are more susceptible to flooding, which is especially useful for large-scale planning and allocation of resources for protection against future flood risk.

Keurbooms Estuary floods and sedimentation

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Eckart H. Schumann

2015-11-01

Full Text Available The Keurbooms Estuary at Plettenberg Bay lies on a wave-dominated, microtidal coast. It has a dune-topped sandy barrier, or barrier dune, almost 4 km long, with a narrow back-barrier lagoon connected to its source rivers, the Keurbooms and Bitou. The estuary exits to the sea through this barrier dune, and it is the geomorphology and mouth position in relation to floods, which is the subject of this paper. Measurements of rainfall, water level, waves and high- and low-tide water lines were used to analyse the mouth variability over the years 2006–2012. Two major floods occurred during this time, with the first in November 2007 eroding away more than 500 000 m3 of sediment. The new mouth was established at the Lookout Rocks limit – the first time since 1915. The second flood occurred in July 2012 and opened up a new mouth about 1 km to the north-east; high waves also affected the position of the breach. The mouth has a tendency to migrate southwards against the longshore drift, but at any stage this movement can be augmented or reversed. The effectiveness of floods in breaching a new mouth through the barrier dune depends on the flood size and the nature of the exit channel in the back-barrier lagoon. Other factors such as ocean waves, sea level, vegetative state of the dune and duration of the flood are also important and can determine where the breach occurs, and if the new mouth will dominate the old mouth.

A relative vulnerability estimation of flood disaster using data envelopment analysis in the Dongting Lake region of Hunan

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C.-H. Li

2013-07-01

Full Text Available The vulnerability to flood disaster is addressed by a number of studies. It is of great importance to analyze the vulnerability of different regions and various periods to enable the government to make policies for distributing relief funds and help the regions to improve their capabilities against disasters, yet a recognized paradigm for such studies seems missing. Vulnerability is defined and evaluated through either physical or economic–ecological perspectives depending on the field of the researcher concerned. The vulnerability, however, is the core of both systems as it entails systematic descriptions of flood severities or disaster management units. The research mentioned often has a development perspective, and in this article we decompose the overall flood system into several factors: disaster driver, disaster environment, disaster bearer, and disaster intensity, and take the interaction mechanism among all factors as an indispensable function. The conditions of flood disaster components are demonstrated with disaster driver risk level, disaster environment stability level and disaster bearer sensitivity, respectively. The flood system vulnerability is expressed as vulnerability = f(risk, stability, sensitivity. Based on the theory, data envelopment analysis method (DEA is used to detail the relative vulnerability's spatiotemporal variation of a flood disaster system and its components in the Dongting Lake region. The study finds that although a flood disaster system's relative vulnerability is closely associated with its components' conditions, the flood system and its components have a different vulnerability level. The overall vulnerability is not the aggregation of its components' vulnerability. On a spatial scale, zones central and adjacent to Dongting Lake and/or river zones are characterized with very high vulnerability. Zones with low and very low vulnerability are mainly distributed in the periphery of the Dongting Lake region

Rainfall-runoff modelling and palaeoflood hydrology applied to reconstruct centennial scale records of flooding and aquifer recharge in ungauged ephemeral rivers

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G. Benito

2011-04-01

Full Text Available In this study we propose a multi-source data approach for quantifying long-term flooding and aquifer recharge in ungauged ephemeral rivers. The methodology is applied to the Buffels River, at 9000 km² the largest ephemeral river in Namaqualand (NW South Africa, a region with scarce stream flow records limiting research investigating hydrological response to global change. Daily discharge and annual flood series (1965–2006 were estimated from a distributed rainfall-runoff hydrological model (TETIS using rainfall gauge records located within the catchment. The model was calibrated and validated with data collected during a two year monitoring programme (2005–2006 at two stream flow stations, one each in the upper and lower reaches of the catchment. In addition to the modelled flow records, non-systematic flood data were reconstructed using both sedimentary and documentary evidence. The palaeoflood record identified at least 25 large floods during the last 700 yr; with the largest floods reaching a minimum discharge of 255 m³ s⁻¹ (450 yr return period in the upper basin, and 510 m³ s⁻¹ (100 yr return period in the lower catchment. Since AD 1925, the flood hydrology of the Buffels River has been characterised by a decrease in the magnitude and frequency of extreme floods, with palaeoflood discharges (period 1500–1921 five times greater than the largest modelled floods during the period 1965–2006. Large floods generated the highest hydrograph volumes, however their contribution to aquifer recharge is limited as this depends on other factors such as flood duration and storage capacity of the unsaturated zone prior to the flood. Floods having average return intervals of 5–10 yr (120–140 m³ s⁻¹ and flowing for 12 days are able to fully saturate the Spektakel aquifer in the lower Buffels River basin. Alluvial aquifer storage capacity limiting potential recharge

Pakistan flood damage mapped by UNOSAT at CERN

CERN Multimedia

Katarina Anthony

2010-01-01

As the waters recede, the Pakistan floods are attracting less attention in the world's media. But at the CERN-based headquarters of UNOSAT, the UN Institute for Training and Research Operational Satellite Application Programme, mapping the damage caused by the floods remains the top priority as the “emergency phase” is only now beginning to level off.   Flood analysis in Pakistan from 28 July to 16 September 2010. Credits: © UNOSAT UNOSAT uses impartial, objective data to assess the specifics of a disaster: What surface area has the flood covered? How many bridges and roads have been destroyed? How many areas are impenetrable? Although there are statistical answers to these questions, UNOSAT’s assessment of the damage caused by the Pakistan floods can be simply described in one word: catastrophic. The images used by UNOSAT are taken from a variety of different sources – commercial and scientific. Once a satellite takes an image, the owne...

Detection of mixing dynamics during pumping of a flooded coal mine.

Science.gov (United States)

Elliot, Trevor; Younger, Paul L

2014-01-01

In complex hydrogeological environments the effective management of groundwater quality problems by pump-and-treat operations can be most confidently achieved if the mixing dynamics induced within the aquifer by pumping are well understood. The utility of isotopic environmental tracers (C-, H-, O-, S-stable isotopic analyses and age indicators-(14) C, (3) H) for this purpose is illustrated by the analysis of a pumping test in an abstraction borehole drilled into flooded, abandoned coal mineworkings at Deerplay (Lancashire, UK). Interpretation of the isotope data was undertaken conjunctively with that of major ion hydrochemistry, and interpreted in the context of the particular hydraulic setting of flooded mineworkings to identify the sources and mixing of water qualities in the groundwater system. Initial pumping showed breakdown of initial water quality stratification in the borehole, and gave evidence for distinctive isotopic signatures (δ(34) S(SO4) ≅ -1.6‰, δ(18) O(SO4 ) ≅ +15‰) associated with primary oxidation of pyrite in the zone of water table fluctuation-the first time this phenomenon has been successfully characterized by these isotopes in a flooded mine system. The overall aim of the test pumping-to replace an uncontrolled outflow from a mine entrance in an inconvenient location with a pumped discharge on a site where treatment could be provided-was swiftly achieved. Environmental tracing data illustrated the benefits of pumping as little as possible to attain this aim, as higher rates of pumping induced in-mixing of poorer quality waters from more distant old workings, and/or renewed pyrite oxidation in the shallow subsurface. © 2013, National Ground Water Association.

Analysis and Comparison on the Flood Simulation in Typical Hilly & Semi-mountainous Region

Science.gov (United States)

Luan, Qinghua; Wang, Dong; Zhang, Xiang; Liu, Jiahong; Fu, Xiaoran; Zhang, Kun; Ma, Jun

2017-12-01

Water-logging and flood are both serious in hilly and semi-mountainous cities of China, but the related research is rare. Lincheng Economic Development Zone (EDZ) in Hebei Province as the typical city was selected and storm water management model (SWMM) was applied for flood simulation in this study. The regional model was constructed through calibrating and verifying the runoff coefficient of different flood processes. Different designed runoff processes in five-year, ten-year and twenty-year return periods in basic scenario and in the low impact development (LID) scenario, respectively, were simulated and compared. The result shows that: LID measures have effect on peak reduction in the study area, but the effectiveness is not significant; the effectiveness of lagging peak time is poor. These simulation results provide decision support for the rational construction of LID in the study area, and provide the references for regional rain flood management.

Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

International Nuclear Information System (INIS)

Burkhard, M.; Gruenthal, G.

2009-01-01

A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an intensive elicitation process. Here, the results of one out of four expert groups are presented. The model of this team is based first of all on considerations regarding the large scale tectonics in the context of the Alpine collision, and neotectonic constraints for defining seismic source zones. This leads to a large scale subdivision based on the structural 'architectural' considerations with little input from the present seismicity. Each of the eight large zones was characterized by the style of present-day faulting, fault orientation, and hypo central depth distribution. A further subdivision of the larger zones is performed based on information provided by the seismicity patterns. 58 small source zones have been defined in this way, each of them characterized by the available tectonic constrains, as well as the pros and cons of different existing geologic views connected to them. Of special concern in this respect were the discussion regarding thin skinned vs. thick skinned tectonics, the tectonic origin of the 1356 Basel earthquake, the role of the Permo-Carboniferous graben structures, and finally the seismogenic orientation of faults with respect to the recent crustal stress field. The uncertainties connected to the delimitations of the small source zones have been handled in form of their regrouping, formalized by the logic tree technique. The maximum magnitudes were estimated as discretized probability distribution functions. After de-clustering the used ECOS earthquake catalogue and an analysis of data completeness as a function of time the parameters of the

An overview of the applications for early warning and mapping of the flood events in New Brunswick

DEFF Research Database (Denmark)

Mioc, Darka; McGillivray, E.; Anton, F.

2014-01-01

This paper gives an overview of the on-line flood warning implementation in the province of New Brunswick, Canada. The on-line flood warning applications are available via the “River Watch” website provided by the New Brunswick Department of Environment. Advanced GIS technology combined with hydr....... The searchable historical database containing reports about the impact of past floods and estimated damages provides a valuable insight into the past of the province of New Brunswick and the motivation for development of the system for flood prediction and management....... with hydrological modelling, provide a mapping and visualization tool that can be used by emergency managers and the general public to predict possible flood zones. The applications developed for “River Watch” support the processing of large amounts of digital terrain and hydrological data, which are then...

Flooding and subsidence in the Thames Gateway: impact on insurance loss potential

Science.gov (United States)

Royse, Katherine; Horn, Diane; Eldridge, Jillian; Barker, Karen

2010-05-01

and sediment, or rehydration of sediment under flood water. The latter mechanism may be particularly critical on sites where Holocene sediments are currently protected from flooding and are no longer subsiding. Holocene deposits tend to compress, either under their own weight or under a superimposed load such as made ground, built structures or flood water. If protected dry sediments become flooded in the future, subsidence would be expected to resume. This research project aims to investigate the correlation between flood hazards and subsidence hazards and the effect that these two sources of risk will have on insurance losses in the Thames Gateway. In particular, the research will explore the potential hydrological and geophysical drivers and links between flood and subsidence events within the Thames Gateway, assessing the potential for significant event occurrence within the timescales relevant to insurers. In the first part of the project we have identified flood risk areas within the Thames Gateway development zone which have a high risk of flooding and may be affected by renewed or increased subsidence. This has been achieved through the use of national and local-scale 2D and 3D geo-environmental information such as the Geosure dataset (e.g. swell-shrink, collapsible and compressible deposits data layers), PSI data, thickness of superficial and artificial land deposits, and flood potential data etc. In the second stage of the project we will investigate the hydrological and geophysical links between flooding and subsidence events on developed sites; quantify the insurance loss potential in the Thames Gateway from correlated flooding and subsidence events; consider how climate change will affect risk to developments in the Thames Gateway in the context of subsidence and flooding; and develop new ways of communicating and visualise correlated flood and subsidence risk to a range of stakeholders, including the insurance industry, planners, policy makers and the

Differences in flood hazard projections in Europe – their causes and consequences for decision making

NARCIS (Netherlands)

Kundzewicz, Zbigniew W.; Krysanova, V.; Dankers, R.; Hirabayashi, Y.; Kanae, S.; Hattermann, F. F.; Huang, S.; Milly, P. C. D.; Stoffel, M.H.; Driessen, P. P. J.; Matczak, Piotr; Quevauviller, P.; Schellnhuber, H. J.

2017-01-01

This paper interprets differences in flood hazard projections over Europe and identifies likely sources of discrepancy. Further, it discusses potential implications of these differences for flood risk reduction and adaptation to climate change. The discrepancy in flood hazard projections raises

Mercury net methylation in five tropical flood plain regions of Brazil: high in the root zone of floating macrophyte mats but low in surface sediments and flooded soils.

Science.gov (United States)

Guimarães, J R; Meili, M; Hylander, L D; de Castro e Silva, E; Roulet, M; Mauro, J B; de Lemos, R

2000-10-16

In aquatic systems, bottom sediments have often been considered as the main methylmercury (MeHg) production site. In tropical floodplain areas, however, floating meadows and flooded forests extend over large areas and can be important Hg methylating sites. We present here a cross-system comparison of the Hg net methylation capacity in surface sediments, flooded soils and roots of floating aquatic macrophytes, assayed by in situ incubation with 203Hg and extraction of formed Me203 Hg by acid leaching and toluene. The presence of mono-MeHg was confirmed by thin layer chromatography and other techniques. Study areas included floodplain lakes in the Amazon basin (Tapajós, Negro and Amazon rivers), the Pantanal floodplain (Paraguay river basin), freshwater coastal lagoons in Rio de Janeiro and oxbow lakes in the Mogi-Guaçú river, São Paulo state. Different Hg levels were added in assays performed in 1994-1998, but great care was taken to standardise all other test parameters, to allow data comparisons. Net MeHg production was one order of magnitude higher (mean 13.8%, range 0.28-35) in the living or decomposing roots of floating or rooted macrophyte mats (Eichhornia azurea, E. crassipes, Paspalum sp., Eleocharis sellowiana, Salvinia sp., S. rotundifolia and Scirpus cubensis) than in the surface layer of underlying lake sediments (mean 0.6%, range 0.022-2.5). Methylation in flooded soils presented a wide range and was in some cases similar to the one found in macrophyte roots but usually much lower. In a Tapajós floodplain lake, natural concentrations of MeHg in soil and sediment cores taken along a lake-forest transect agreed well with data on net methylation potentials in the same samples. E. azurea, E. crassipes and Salvinia presented the highest methylation potentials, up to 113 times higher than in sediments. Methylation in E. azurea from six lakes of the Paraguay and Cuiabá rivers, high Pantanal, was determined in the 1998 dry and wet seasons and ranged from

The Role of Green Infrastructure Solutions in Urban Flood Risk Management

OpenAIRE

Soz, Salman Anees; Kryspin-Watson, Jolanta; Stanton-Geddes, Zuzana

2016-01-01

This Knowledge Note explores the role of green infrastructure solutions in urban flood risk management. Green infrastructure solutions represent an approach that focuses on using natural processes for managing wet weather impacts while delivering environmental, social, and economic benefits. Green infrastructure solutions, such as wetlands, bioshields, buffer zones, green roofing, street s...

Application of Flood Nomograph for Flood Forecasting in Urban Areas

Directory of Open Access Journals (Sweden)

Eui Hoon Lee

2018-01-01

Full Text Available Imperviousness has increased due to urbanization, as has the frequency of extreme rainfall events by climate change. Various countermeasures, such as structural and nonstructural measures, are required to prepare for these effects. Flood forecasting is a representative nonstructural measure. Flood forecasting techniques have been developed for the prevention of repetitive flood damage in urban areas. It is difficult to apply some flood forecasting techniques using training processes because training needs to be applied at every usage. The other flood forecasting techniques that use rainfall data predicted by radar are not appropriate for small areas, such as single drainage basins. In this study, a new flood forecasting technique is suggested to reduce flood damage in urban areas. The flood nomograph consists of the first flooding nodes in rainfall runoff simulations with synthetic rainfall data at each duration. When selecting the first flooding node, the initial amount of synthetic rainfall is 1 mm, which increases in 1 mm increments until flooding occurs. The advantage of this flood forecasting technique is its simple application using real-time rainfall data. This technique can be used to prepare a preemptive response in the process of urban flood management.

Low cost, multiscale and multi-sensor application for flooded area mapping

Directory of Open Access Journals (Sweden)

D. Giordan

2018-05-01

Full Text Available Flood mapping and estimation of the maximum water depth are essential elements for the first damage evaluation, civil protection intervention planning and detection of areas where remediation is needed. In this work, we present and discuss a methodology for mapping and quantifying flood severity over floodplains. The proposed methodology considers a multiscale and multi-sensor approach using free or low-cost data and sensors. We applied this method to the November 2016 Piedmont (northwestern Italy flood. We first mapped the flooded areas at the basin scale using free satellite data from low- to medium-high-resolution from both the SAR (Sentinel-1, COSMO-Skymed and multispectral sensors (MODIS, Sentinel-2. Using very- and ultra-high-resolution images from the low-cost aerial platform and remotely piloted aerial system, we refined the flooded zone and detected the most damaged sector. The presented method considers both urbanised and non-urbanised areas. Nadiral images have several limitations, in particular in urbanised areas, where the use of terrestrial images solved this limitation. Very- and ultra-high-resolution images were processed with structure from motion (SfM for the realisation of 3-D models. These data, combined with an available digital terrain model, allowed us to obtain maps of the flooded area, maximum high water area and damaged infrastructures.

Quantifying the performance of automated GIS-based geomorphological approaches for riparian zone delineation using digital elevation models

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D. Fernández

2012-10-01

Full Text Available Riparian zone delineation is a central issue for managing rivers and adjacent areas; however, criteria used to delineate them are still under debate. The area inundated by a 50-yr flood has been indicated as an optimal hydrological descriptor for riparian areas. This detailed hydrological information is usually only available for populated areas at risk of flooding. In this work we created several floodplain surfaces by means of two different GIS-based geomorphological approaches using digital elevation models (DEMs, in an attempt to find hydrologically meaningful potential riparian zones for river networks at the river basin scale. Objective quantification of the performance of the two geomorphologic models is provided by analysing coinciding and exceeding areas with respect to the 50-yr flood surface in different river geomorphological types.

Analysis of Hydrological Sensitivity for Flood Risk Assessment

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Sanjay Kumar Sharma

2018-02-01

Full Text Available In order for the Indian government to maximize Integrated Water Resource Management (IWRM, the Brahmaputra River has played an important role in the undertaking of the Pilot Basin Study (PBS due to the Brahmaputra River’s annual regional flooding. The selected Kulsi River—a part of Brahmaputra sub-basin—experienced severe floods in 2007 and 2008. In this study, the Rainfall-Runoff-Inundation (RRI hydrological model was used to simulate the recent historical flood in order to understand and improve the integrated flood risk management plan. The ultimate objective was to evaluate the sensitivity of hydrologic simulation using different Digital Elevation Model (DEM resources, coupled with DEM smoothing techniques, with a particular focus on the comparison of river discharge and flood inundation extent. As a result, the sensitivity analysis showed that, among the input parameters, the RRI model is highly sensitive to Manning’s roughness coefficient values for flood plains, followed by the source of the DEM, and then soil depth. After optimizing its parameters, the simulated inundation extent showed that the smoothing filter was more influential than its simulated discharge at the outlet. Finally, the calibrated and validated RRI model simulations agreed well with the observed discharge and the Moderate Imaging Spectroradiometer (MODIS-detected flood extents.

Probabilistic Flood Defence Assessment Tools

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Slomp Robert

2016-01-01

Full Text Available The WTI2017 project is responsible for the development of flood defence assessment tools for the 3600 km of Dutch primary flood defences, dikes/levees, dunes and hydraulic structures. These tools are necessary, as per January 1st 2017, the new flood risk management policy for the Netherlands will be implemented. Then, the seven decades old design practice (maximum water level methodology of 1958 and two decades old safety standards (and maximum hydraulic load methodology of 1996 will formally be replaced by a more risked based approach for the national policy in flood risk management. The formal flood defence assessment is an important part of this new policy, especially for flood defence managers, since national and regional funding for reinforcement is based on this assessment. This new flood defence policy is based on a maximum allowable probability of flooding. For this, a maximum acceptable individual risk was determined at 1/100 000 per year, this is the probability of life loss of for every protected area in the Netherlands. Safety standards of flood defences were then determined based on this acceptable individual risk. The results were adjusted based on information from cost -benefit analysis, societal risk and large scale societal disruption due to the failure of critical infrastructure e.g. power stations. The resulting riskbased flood defence safety standards range from a 300 to a 100 000 year return period for failure. Two policy studies, WV21 (Safety from floods in the 21st century and VNK-2 (the National Flood Risk in 2010 provided the essential information to determine the new risk based safety standards for flood defences. The WTI2017 project will provide the safety assessment tools based on these new standards and is thus an essential element for the implementation of this policy change. A major issue to be tackled was the development of user-friendly tools, as the new assessment is to be carried out by personnel of the

Harvesting Social Media for Generation of Near Real-time Flood Maps

NARCIS (Netherlands)

Eilander, Dirk; Trambauer, Patricia; Wagemaker, Jurjen; Van Loenen, Arnejan

2016-01-01

Social media are a new, big and exciting source of data. Rather than from traditional sensors and models, this data is from local people experiencing real-world phenomena, such as flood events. During floods, disaster managers often have trouble getting an accurate overview of the current situation.

Technical Guidance Manual: Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

Science.gov (United States)

2017-06-20

zone, the site must be:  Comprised of unconsolidated material (gravel, sand, silt, clay )  Have access around the source zone to building the...lower low permeability unit such as a clay to prevent up flow  For accessing the lower cost silica gel grouting technology, the hydraulic...hydraulic conductivity with sodium silicate grout.” (page 4-20).  Viscosities of typical grouts (Powers Figure 22.10)  Typical properties of Sodium

Loss of life in flood events

Science.gov (United States)

Špitalar, Maruša

2013-04-01

Natural disasters per se give a negative connotation. They are destructive to material elements in a space, nature itself and represent a threat to peoples' lives and health. Floods, especially flash floods due to its power and happening suddenly cause extensive damage. Hence, they are hard to predict and are characterized with violent movement, lots of lives are lost. Floods are among natural hazards the one causing the highest number of fatalities. Having said that very important aspects are humans' vulnerability, risk perception, their behavior when confronted with hazardous situations and on the other hand issues related to adequate warning signs and canals of communication. It is very important to take into consideration this segments also and not mainly just structural measures. However the aim of this paper is to emphasis mainly the social aspects of floods. It consists of two main parts. First one refers to mans' vulnerability, risk perception when it comes to danger caused by rising waters and how does culture influences peoples' response and reaction to flood causalities. The second part consists of data about detailed information on circumstances of death that have been collected from several different sources from several EU countries. There has been also available information on the age and gender of people who lost lives in flood events. With gender males dominated among death people since tend to risk more in risky situations. There has been also defined a vulnerable age group among flood fatalities. Analysis of circumstance of death enabled us to define risky groups that are very important for flood managers. Further on this is very beneficial also for risk prevention, early warning systems and creating the best canals in order to information about upcoming danger would successfully reach people at hazardous areas and also for the others to avoid them.

Flood and Weather Monitoring Using Real-time Twitter Data Streams

Science.gov (United States)

Demir, I.; Sit, M. A.; Sermet, M. Y.

2016-12-01

Social media data is a widely used source to making inference within public crisis periods and events in disaster times. Specifically, since Twitter provides large-scale data publicly in real-time, it is one of the most extensive resources with location information. This abstract provides an overview of a real-time Twitter analysis system to support flood preparedness and response using a comprehensive information-centric flood ontology and natural language processing. Within the scope of this project, we deal with acquisition and processing of real-time Twitter data streams. System fetches the tweets with specified keywords and classifies them as related to flooding or heavy weather conditions. The system uses machine learning algorithms to discover patterns using the correlation between tweets and Iowa Flood Information System's (IFIS) extensive resources. The system uses these patterns to forecast the formation and progress of a potential future flood event. While fetching tweets, predefined hashtags are used for filtering and enhancing the relevancy for selected tweets. With this project, tweets can also be used as an alternative data source where other data sources are not sufficient for specific tasks. During the disasters, the photos that people upload alongside their tweets can be collected and placed to appropriate locations on a mapping system. This allows decision making authorities and communities to see the most recent outlook of the disaster interactively. In case of an emergency, concentration of tweets can help the authorities to determine a strategy on how to reach people most efficiently while providing them the supplies they need. Thanks to the extendable nature of the flood ontology and framework, results from this project will be a guide for other natural disasters, and will be shared with the community.

The efficiency of asset management strategies to reduce urban flood risk.

Science.gov (United States)

ten Veldhuis, J A E; Clemens, F H L R

2011-01-01

In this study, three asset management strategies were compared with respect to their efficiency to reduce flood risk. Data from call centres at two municipalities were used to quantify urban flood risks associated with three causes of urban flooding: gully pot blockage, sewer pipe blockage and sewer overloading. The efficiency of three flood reduction strategies was assessed based on their effect on the causes contributing to flood risk. The sensitivity of the results to uncertainty in the data source, citizens' calls, was analysed through incorporation of uncertainty ranges taken from customer complaint literature. Based on the available data it could be shown that increasing gully pot blockage is the most efficient action to reduce flood risk, given data uncertainty. If differences between cause incidences are large, as in the presented case study, call data are sufficient to decide how flood risk can be most efficiently reduced. According to the results of this analysis, enlargement of sewer pipes is not an efficient strategy to reduce flood risk, because flood risk associated with sewer overloading is small compared to other failure mechanisms.

Spatial Scaling of Global Rainfall and Flood Extremes

Science.gov (United States)

Devineni, Naresh; Lall, Upmanu; Xi, Chen; Ward, Philip

2014-05-01

Floods associated with severe storms are a significant source of risk for property, life and supply chains. These property losses tend to be determined as much by the duration and spatial extent of flooding as by the depth and velocity of inundation. High duration floods are typically induced by persistent rainfall (up to 30 day duration) as seen recently in Thailand, Pakistan, the Ohio and the Mississippi Rivers, France, and Germany. Events related to persistent and recurrent rainfall appear to correspond to the persistence of specific global climate patterns that may be identifiable from global, historical data fields, and also from climate models that project future conditions. In this paper, we investigate the statistical properties of the spatial manifestation of the rainfall exceedances and floods. We present the first ever results on a global analysis of the scaling characteristics of extreme rainfall and flood event duration, volumes and contiguous flooded areas as a result of large scale organization of long duration rainfall events. Results are organized by latitude and with reference to the phases of ENSO, and reveal surprising invariance across latitude. Speculation as to the potential relation to the dynamical factors is presented

Paddle River Dam : review of probable maximum flood

Energy Technology Data Exchange (ETDEWEB)

Clark, D. [UMA Engineering Ltd., Edmonton, AB (Canada); Neill, C.R. [Northwest Hydraulic Consultants Ltd., Edmonton, AB (Canada)

2008-07-01

The Paddle River Dam was built in northern Alberta in the mid 1980s for flood control. According to the 1999 Canadian Dam Association (CDA) guidelines, this 35 metre high, zoned earthfill dam with a spillway capacity sized to accommodate a probable maximum flood (PMF) is rated as a very high hazard. At the time of design, it was estimated to have a peak flow rate of 858 centimetres. A review of the PMF in 2002 increased the peak flow rate to 1,890 centimetres. In light of a 2007 revision of the CDA safety guidelines, the PMF was reviewed and the inflow design flood (IDF) was re-evaluated. This paper discussed the levels of uncertainty inherent in PMF determinations and some difficulties encountered with the SSARR hydrologic model and the HEC-RAS hydraulic model in unsteady mode. The paper also presented and discussed the analysis used to determine incremental damages, upon which a new IDF of 840 m{sup 3}/s was recommended. The paper discussed the PMF review, modelling methodology, hydrograph inputs, and incremental damage of floods. It was concluded that the PMF review, involving hydraulic routing through the valley bottom together with reconsideration of the previous runoff modeling provides evidence that the peak reservoir inflow could reasonably be reduced by approximately 20 per cent. 8 refs., 5 tabs., 8 figs.

Development of a Probabilistic Flood Hazard Assessment (PFHA) for the nuclear safety

Science.gov (United States)

Ben Daoued, Amine; Guimier, Laurent; Hamdi, Yasser; Duluc, Claire-Marie; Rebour, Vincent

2016-04-01

The purpose of this study is to lay the basis for a probabilistic evaluation of flood hazard (PFHA). Probabilistic assessment of external floods has become a current topic of interest to the nuclear scientific community. Probabilistic approaches complement deterministic approaches by exploring a set of scenarios and associating a probability to each of them. These approaches aim to identify all possible failure scenarios, combining their probability, in order to cover all possible sources of risk. They are based on the distributions of initiators and/or the variables caracterizing these initiators. The PFHA can characterize the water level for example at defined point of interest in the nuclear site. This probabilistic flood hazard characterization takes into account all the phenomena that can contribute to the flooding of the site. The main steps of the PFHA are: i) identification of flooding phenomena (rains, sea water level, etc.) and screening of relevant phenomena to the nuclear site, ii) identification and probabilization of parameters associated to selected flooding phenomena, iii) spreading of the probabilized parameters from the source to the point of interest in the site, v) obtaining hazard curves and aggregation of flooding phenomena contributions at the point of interest taking into account the uncertainties. Within this framework, the methodology of the PFHA has been developed for several flooding phenomena (rain and/or sea water level, etc.) and then implemented and tested with a simplified case study. In the same logic, our study is still in progress to take into account other flooding phenomena and to carry out more case studies.

Spatial and temporal variability of nitrate sinks and sources in riparian soils of a restored reach of an Alpine river

Science.gov (United States)

Luster, Jörg; Huber, Benjamin; Shrestha, Juna; Samaritani, Emanuela; Niklaus, Pascal A.

2010-05-01

grass zone and lower part of the bush zone while the first and third floods were bigger and swept through all the FPZs. Soil solution was sampled periodically using suction cups installed at several soil depths and operated at a constant vacuum. There were six spatial replicates for each FPZ and depth. Overall there was high spatial and temporal variability of leachable nitrate. The local history of environmental conditions was as important as the characteristic behavior of a given FPZ. While the subsoil of the grass zone and the mixed forest often acted as nitrate source when compared to river and groundwater, the bush zone was generally characterized by low nitrate concentrations. The latter were attributed to strong uptake by willow and the occurrence of denitrification hot spots in the subsoil. In the topsoil of all FPZ, however, locally very high nitrate concentrations occurred for short periods after major floods. In this presentation we will relate the variability of nitrate concentrations to (i) groundwater level, (ii) soil environmental parameters, chiefly moisture and temperature, (iii) concentration of related substances in soil solution, (iv) chemical, physical and biological properties of the soil solid phase, and (v) rates of biological nitrogen transformations including nitrification, denitrification and plant uptake.

A 320-year long series of Danube floods in Central Hungary (Budapest and Pest County): a frequency-magnitude-seasonality overview

Science.gov (United States)

Kiss, Andrea; Salinas, Jose; Bloeschl, Guenter

2015-04-01

The present paper is based on a recently developed database including contemporary original, administrative, legal and private source materials (published and archival) as well as media reports related to the floods occurred in the town of Budapest (historical towns of Pest, Buda) and Central Hungary (historical Pest-Pilis-Solt County). As for the archival evidence, main bases of investigation are the administrative sources such as town council protocols and county meeting protocols of Budapest and historical Pest-Pilis-Solt County: in these (legal-)administrative documents damaging events (natural/environmental hazards) were systematically recorded. Moreover, other source types such as taxation-related damage accounts as well as private and official reports, letters and correspondence (published, unpublished) were also included. Concerning published evidence, a most important source is flood reports in contemporary newspapers; however, other published sources (e.g. narratives, fund raising circulars etc.; both published and unpublished) also contained useful flood-related information. Beyond providing information on the strength and weaknesses of different sources types and the temporal and spatial distribution of evidence, a general background on the contemporary environmental and hydrological/hydromorphological conditions of the study area (and its changes during and after river regulations) are also provided. However, in the presentation the main focus is on the analysis of flood rich flood poor periods of the last more than 300 years; furthermore, the seasonality distribution as well as the magnitude of Danube flood events - and their spatial differences are discussed. In case of Budapest and Central Hungary, with respect to the greatest flood events, ice jam floods played a rather significant role before river regulation works. Due to this fact the main types of flood events (including their main causes), with special emphasis on ice jam floods, are discussed

Expression of root-related transcription factors associated with flooding tolerance of soybean (Glycine max).

Science.gov (United States)

Valliyodan, Babu; Van Toai, Tara T; Alves, Jose Donizeti; de Fátima P Goulart, Patricia; Lee, Jeong Dong; Fritschi, Felix B; Rahman, Mohammed Atiqur; Islam, Rafiq; Shannon, J Grover; Nguyen, Henry T

2014-09-29

Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs) associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of these genes will be

Expression of Root-Related Transcription Factors Associated with Flooding Tolerance of Soybean (Glycine max

Directory of Open Access Journals (Sweden)

Babu Valliyodan

2014-09-01

Full Text Available Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of

Field Experiments Aimed To The Analysis of Flood Generation Processes

Science.gov (United States)

Carriero, D.; Iacobellis, V.; Oliveto, G.; Romano, N.; Telesca, V.; Fiorentino, M.

The study of the soil moisture dynamics and of the climate-soil-vegetation interac- tion is essential for the comprehension of possible climatic change phenomena, as well as for the analysis of occurrence of extreme hydrological events. In this trend the theoretically-based distribution of floods recently derived by Fiorentino and Ia- cobellis, [ŞNew insights about the climatic and geologic control on the probability distribution of floodsT, Water Resources Research, 2001, 37: 721-730] demonstrated, by an application in some Southern Italy basins, that processes at the hillslope scale strongly influence the basin response by means of the different mechanisms of runoff generation produced by various distributions of partial area contributing. This area is considered as a stochastic variable whose pdf position parameter showed strong de- pendence on the climate as it can seen in the studied basins behavior: in dry zones, where there is the prevalence of the infiltration excess (Horton) mechanism, the basin water loss parameter decreases as basin area increases and the flood peak source area depends on the permeability of soils; in humid zones, with the prevalence of satu- ration excess (Dunne) process, the loss parameter seems independent from the basin area and very sensitive to simple climatic index while only small portion of the area invested by the storm contributes to floods. The purpose of this work is to investigate the consistency of those interpretations by means of field experiments at the hillslope scale to establish a parameterization accounting for soil physical and hydraulic prop- erties, vegetation characteristics and land-use. The research site is the catchment of River Fiumarella di Corleto, which is located in Basilicata Region, Italy, and has a drainage area of approximately 32 km2. The environment has a rather dynamic geo- morphology and very interesting features from the soil-landscape modeling viewpoint [Santini A., A. Coppola, N. Romano, and

Mapping flood and flooding potential indices: a methodological approach to identifying areas susceptible to flood and flooding risk. Case study: the Prahova catchment (Romania)

Science.gov (United States)

Zaharia, Liliana; Costache, Romulus; Prăvălie, Remus; Ioana-Toroimac, Gabriela

2017-04-01

Given that floods continue to cause yearly significant worldwide human and material damages, flood risk mitigation is a key issue and a permanent challenge in developing policies and strategies at various spatial scales. Therefore, a basic phase is elaborating hazard and flood risk maps, documents which are an essential support for flood risk management. The aim of this paper is to develop an approach that allows for the identification of flash-flood and flood-prone susceptible areas based on computing and mapping of two indices: FFPI (Flash-Flood Potential Index) and FPI (Flooding Potential Index). These indices are obtained by integrating in a GIS environment several geographical variables which control runoff (in the case of the FFPI) and favour flooding (in the case of the FPI). The methodology was applied in the upper (mountainous) and middle (hilly) catchment of the Prahova River, a densely populated and socioeconomically well-developed area which has been affected repeatedly by water-related hazards over the past decades. The resulting maps showing the spatialization of the FFPI and FPI allow for the identification of areas with high susceptibility to flashfloods and flooding. This approach can provide useful mapped information, especially for areas (generally large) where there are no flood/hazard risk maps. Moreover, the FFPI and FPI maps can constitute a preliminary step for flood risk and vulnerability assessment.

FLOOD RISK ASSESSMENT IN RIVER TIMIS BASIN - THE CARANSEBES - LUGOJ SECTOR- USING GIS TECHNIQUE

Directory of Open Access Journals (Sweden)

MIHAI VALENTIN HERBEI

2012-11-01

Full Text Available Flood risk assessment in Timis River basin - the Caransebes -Lugoj sector- using GIS technique. Over time freshets, thus floods constituted and constitute a particularly important issue that requires attention. In many cases, flood damages are extensive to the environment, to the economy and also socially. The purpose of this paper is to identify flood-prone areas between Caransebes and Lugoj, land that is part of the Timis river basin. This paper is based on a theoretical model in which we considered the building elements of the flood produced on the Timis river in April 2005 (levels and flows. to represent the zones flood – prone, we used the numerical model of the terrain, created for the abovementioned area. On this model , according to levels measured at hydrometric stations, were defined those flood prone areas. The Timis river hydrographic basin includes a varied terrain (mountains, hills and plains, with pronounced differences in altitude and massiveness, resulting from tectonic movements that have affected the region, this fact has affected water flow processes, both directly through fragmentation and slope, and indirectly, by creating the vertical climate, vegetation and soils zones. Using GIS technology to study hydrological phenomena and their impact on the geographic area are of particular importance due to the complexity of these techniques, which enables detailed analysis and analytical precision as well as an increased speed of the analysis. Creating theoretical models that give scale to the hydrological phenomena, in this case representing the flood areas, is of great practical importance because based on these models the areas can be defined and viewed, having the possibility of taking measures to prevent environmental effects on the natural and / or anthropogenic environment. In the studied area review of the flood of 2005, were represented flood areas, therefore, according with the researches, several villages, located in

Adige river in Trento flooding map, 1892: private or public risk transfer?

Science.gov (United States)

Ranzi, Roberto

2016-04-01

For the determination of the flood risk hydrologist and hydraulic engineers focuse their attention mainly to the estimation of physical factors determining the flood hazard, while economists and experts of social sciences deal mainly with the estimation of vulnerability and exposure. The fact that flood zoning involves both hydrological and socio-economic aspects, however, was clear already in the XIX century when the impact of floods on inundated areas started to appear in flood maps, for instance in the UK and in Italy. A pioneering 'flood risk' map for the Adige river in Trento, Italy, was already published in 1892, taking into account in detail both hazard intensity in terms of velocity and depth, frequency of occurrence, vulnerability and economic costs for flood protection with river embankments. This map is likely to be the reinterpreted certainly as a pioneering, and possibly as the first flood risk map for an Italian river and worldwide. Risk levels were divided in three categories and seven sub-categories, depending on flood water depth, velocity, frequency and damage costs. It is interesting to notice the fact that at that time the map was used to share the cost of levees' reparation and enhancement after the severe September 1882 flood as a function of the estimated level of protection of the respective areas against the flood risk. The sharing of costs between public bodies, the railway company and private owners was debated for about 20 years and at the end the public sustained the major costs. This shows how already at that time the economic assessment of structural flood protections was based on objective and rational cost-benefit criteria, that hydraulic risk mapping was perceived by the society as fundamental for the design of flood protection systems and that a balanced cost sharing between public and private was an accepted approach although some protests arose at that time.

Study of the adaptive refinement on an open source 2D shallow-water flow solver using quadtree grid for flash flood simulations.

Science.gov (United States)

Kirstetter, G.; Popinet, S.; Fullana, J. M.; Lagrée, P. Y.; Josserand, C.

2015-12-01

The full resolution of shallow-water equations for modeling flash floods may have a high computational cost, so that majority of flood simulation softwares used for flood forecasting uses a simplification of this model : 1D approximations, diffusive or kinematic wave approximations or exotic models using non-physical free parameters. These kind of approximations permit to save a lot of computational time by sacrificing in an unquantified way the precision of simulations. To reduce drastically the cost of such 2D simulations by quantifying the lost of precision, we propose a 2D shallow-water flow solver built with the open source code Basilisk1, which is using adaptive refinement on a quadtree grid. This solver uses a well-balanced central-upwind scheme, which is at second order in time and space, and treats the friction and rain terms implicitly in finite volume approach. We demonstrate the validity of our simulation on the case of the flood of Tewkesbury (UK) occurred in July 2007, as shown on Fig. 1. On this case, a systematic study of the impact of the chosen criterium for adaptive refinement is performed. The criterium which has the best computational time / precision ratio is proposed. Finally, we present the power law giving the computational time in respect to the maximum resolution and we show that this law for our 2D simulation is close to the one of 1D simulation, thanks to the fractal dimension of the topography. [1] http://basilisk.fr/

Exploitation of Documented Historical Floods for Achieving Better Flood Defense

Directory of Open Access Journals (Sweden)

Slobodan Kolaković

2016-01-01

Full Text Available Establishing Base Flood Elevation for a stream network corresponding to a big catchment is feasible by interdisciplinary approach, involving stochastic hydrology, river hydraulics, and computer aided simulations. A numerical model calibrated by historical floods has been exploited in this study. The short presentation of the catchment of the Tisza River in this paper is followed by the overview of historical floods which hit the region in the documented period of 130 years. Several well documented historical floods provided opportunity for the calibration of the chosen numerical model. Once established, the model could be used for investigation of different extreme flood scenarios and to establish the Base Flood Elevation. The calibration has shown that the coefficient of friction in case of the Tisza River is dependent both on the actual water level and on the preceding flood events. The effect of flood plain maintenance as well as the activation of six potential detention ponds on flood mitigation has been examined. Furthermore, the expected maximum water levels have also been determined for the case if the ever observed biggest 1888 flood hit the region again. The investigated cases of flood superposition highlighted the impact of tributary Maros on flood mitigation along the Tisza River.

Floods, civil protection and inhabitants of San Mateo Atenco, State of Mexico

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Alejandra Toscana Aparicio

2010-09-01

Full Text Available According to the national civil protection and the State of Mexico´s civil protection systems, the municipality order is the first instance on attending the emergency situations; in order to do it, each municipality must have a civil protection system. In this essay it is exposed the case of the municipality San Mateo Atenco, constantly affected by floods that are produced by the physical characteristics of the zone, the anthropic transformations to the natural environment and the government decisions and omissions. It is analyzed the discrepancies between municipality authorities and the population affected by floods; in order to do it, a flood map based on testimonies was made, a vulnerability map, and a survey of the opinion of the San Mateo Atenco´s population about the civil protection municipality authorities´ performance.

Influence of Flood Detention Capability in Flood Prevention for Flood Disaster of Depression Area

OpenAIRE

Chia Lin Chan; Yi Ju Yang; Chih Chin Yang

2011-01-01

Rainfall records of rainfall station including the rainfall potential per hour and rainfall mass of five heavy storms are explored, respectively from 2001 to 2010. The rationalization formula is to investigate the capability of flood peak duration of flood detention pond in different rainfall conditions. The stable flood detention model is also proposed by using system dynamic control theory to get the message of flood detention pond in this research. When rainfall freque...

Flood risk assessment in France: comparison of extreme flood estimation methods (EXTRAFLO project, Task 7)

Science.gov (United States)

Garavaglia, F.; Paquet, E.; Lang, M.; Renard, B.; Arnaud, P.; Aubert, Y.; Carre, J.

2013-12-01

of five watersheds located in the South of France. References : O. CAYLA : Probability calculation of design floods abd inflows - SPEED. Waterpower 1995, San Francisco, California 1995 CFGB : Design flood determination by the gradex method. Bulletin du Comité Français des Grands Barrages News 96, 18th congress CIGB-ICOLD n2, nov:108, 1994. F. GARAVAGLIA et al. : Introducing a rainfall compound distribution model based on weather patterns subsampling. Hydrology and Earth System Sciences, 14, 951-964, 2010. J. LAVABRE et al. : SHYREG : une méthode pour l'estimation régionale des débits de crue. application aux régions méditerranéennes françaises. Ingénierie EAT, 97-111, 2003. M. MARGOUM : Estimation des crues rares et extrêmes : le modèle AGREGEE. Conceptions et remières validations. PhD, Ecole des Mines de Paris, 1992. R. NAULET et al. : Flood frequency analysis on the Ardèche river using French documentary sources from the two last centuries. Journal of Hydrology, 313:58-78, 2005. E. PAQUET et al. : The SCHADEX method: A semi-continuous rainfall-runoff simulation for extreme flood estimation, Journal of Hydrology, 495, 23-37, 2013.

A Strategy for a Parametric Flood Insurance Using Proxies

Science.gov (United States)

Haraguchi, M.; Lall, U.

2017-12-01

Traditionally, the design of flood control infrastructure and flood plain zoning require the estimation of return periods, which have been calculated by river hydraulic models with rainfall-runoff models. However, this multi-step modeling process leads to significant uncertainty to assess inundation. In addition, land use change and changing climate alter the potential losses, as well as make the modeling results obsolete. For these reasons, there is a strong need to create parametric indexes for the financial risk transfer for large flood events, to enable rapid response and recovery. Hence, this study examines the possibility of developing a parametric flood index at the national or regional level in Asia, which can be quickly mobilized after catastrophic floods. Specifically, we compare a single trigger based on rainfall index with multiple triggers using rainfall and streamflow indices by conducting case studies in Bangladesh and Thailand. The proposed methodology is 1) selecting suitable indices of rainfall and streamflow (if available), 2) identifying trigger levels for specified return periods for losses using stepwise and logistic regressions, 3) measuring the performance of indices, and 4) deriving return periods of selected windows and trigger levels. Based on the methodology, actual trigger levels were identified for Bangladesh and Thailand. Models based on multiple triggers reduced basis risks, an inherent problem in an index insurance. The proposed parametric flood index can be applied to countries with similar geographic and meteorological characteristics, and serve as a promising method for ex-ante risk financing for developing countries. This work is intended to be a preliminary work supporting future work on pricing risk transfer mechanisms in ex-ante risk finance.

Estimating flood discharge using witness movies in post-flood hydrological surveys

Science.gov (United States)

Le Coz, Jérôme; Hauet, Alexandre; Le Boursicaud, Raphaël; Pénard, Lionel; Bonnifait, Laurent; Dramais, Guillaume; Thollet, Fabien; Braud, Isabelle

2015-04-01

surveys were achieved. Identifying fixed GCPs is more difficult in rural environments than in urban areas. Image processing was performed using free software only, especially Fudaa-LSPIV (Le Coz et al., 2014) was used for steps (v), (vi), and (vii). The results illustrate the typical issues and advantages of flood home movies taken by witnesses for improving post-flood discharge estimation. In spite of the non-ideal conditions related to such movies, the LSPIV technique was successfully applied. Corrections for lens distortion and limited camera movements (shake) are not difficult to achieve. Locating precisely the video viewpoint is often easy whereas precise timing may be not, especially when the author cannot be contacted or when the camera clock is false. Based on sensitivity analysis, the determination of the water level appears to be the main source of uncertainty in the results. Nevertheless, the information content of the results remains highly valuable for post-flood studies, in particular for improving the high-flow extrapolation of hydrometric rating curves. This kind of application opens interesting avenues for participative research in flood hydrology, as well as the study of other extreme geophysical events. Typically, as part of the FloodScale ANR research project (2012-2015), specific communication actions have been focused on the determination of flood discharges within the Ardèche river catchement (France) using home movies shared by observers and volunteers. Safety instructions and a simplified field procedure were shared through local media and were made available in French and English on the project website. This way, simple flood observers or even some enthusiastic flood chasers can contribute to participative hydrological science in the same way the so-called storm chasers have significantly contributed to meteorological science since the Tornado Intercept Project (1972). Website : http

Floods of 1971 and 1972 on Glover Creek and Little River in southeastern Oklahoma

Science.gov (United States)

Thomas, Wilbert O.; Corley, Robert K.

1973-01-01

Heavy rains of December 9-10, 1971, and Oct. 30-31, 1972, caused outstanding floods on Glover Creek and Little River in McCurtain County in southeastern Oklahoma. This report presents hydrologic data that document the extent of flooding, flood profiles, and frequency of flooding on reaches of both streams. The data presented provide a technical basis for formulating effective flood-plain zoning that will minimize existing and future flood problems. The report also can be useful for locating waste-disposal and water-treatment facilities, and for the development of recreational areas. The area studied includes the reach of Little River on the Garvin and Idabel 7 1/2-minute quadrangles (sheet 1) and the reach of Glover Creek on the southwest quarter of the Golden 15-minute quadrangle (sheet 2). The flood boundaries delineated on the maps are the limits of flooding during the December 1971 and October 1972 floods. Any attempt to delineate the flood boundaries on streams in the study area other than Glover Creek and Little River was considered to be beyond the scope of this report. The general procedure used in defining the flood boundaries was to construct the flood profiles from high-water marks obtained by field surveys and by records at three stream-gaging stations (two on Little River and one on Glover Creek.). The extent of flooding was delineated on the topographic maps by using the flood profiles to define the flood elevations at various points along the channel and locating the elevations on the map by interpolating between contours (lines of equal ground elevation). In addition, flood boundaries were defined in places by field survey, aerial photographs, and information from local residents. The accuracy of the flood boundaries is consistent with the scale and contour interval of the maps (1 inch = 2,000 feet; contour interval 10 and 20 feet), which means the flood boundaries are drawn as accurately as possible on maps having 10- and 20-foot contour intervals.

Effects of Flood Control Strategies on Flood Resilience Under Sociohydrological Disturbances

Science.gov (United States)

Sung, Kyungmin; Jeong, Hanseok; Sangwan, Nikhil; Yu, David J.

2018-04-01

A community capacity to cope with flood hazards, or community flood resilience, emerges from the interplay of hydrological and social processes. This interplay can be significantly influenced by the flood control strategy adopted by a society, i.e., how a society sets its desired flood protection level and strives to achieve this goal. And this interplay can be further complicated by rising land-sea level differences, seasonal water level fluctuations, and economic change. But not much research has been done on how various forms of flood control strategies affect human-flood interactions under these disturbances and therefore flood resilience in the long run. The current study is an effort to address these issues by developing a conceptual model of human-flood interaction mediated by flood control strategies. Our model extends the existing model of Yu et al. (2017), who investigated the flood resilience of a community-based flood protection system in coastal Bangladesh. The major extensions made in this study are inclusions of various forms of flood control strategies (both adaptive and nonadaptive ones), the challenge of rising land-sea level differences, and various high tide level scenarios generated from modifying the statistical variances and averages. Our results show that adaptive forms of flood control strategies tend to outperform nonadaptive ones for maintaining the model community's flood protection system. Adaptive strategies that dynamically adjust target flood protection levels through close monitoring of flood damages and social memories of flood risk can help the model community deal with various disturbances.

Public perception of flood risks, flood forecasting and mitigation

Directory of Open Access Journals (Sweden)

M. Brilly

2005-01-01

Full Text Available A multidisciplinary and integrated approach to the flood mitigation decision making process should provide the best response of society in a flood hazard situation including preparation works and post hazard mitigation. In Slovenia, there is a great lack of data on social aspects and public response to flood mitigation measures and information management. In this paper, two studies of flood perception in the Slovenian town Celje are represented. During its history, Celje was often exposed to floods, the most recent serious floods being in 1990 and in 1998, with a hundred and fifty return period and more than ten year return period, respectively. Two surveys were conducted in 1997 and 2003, with 157 participants from different areas of the town in the first, and 208 in the second study, aiming at finding the general attitude toward the floods. The surveys revealed that floods present a serious threat in the eyes of the inhabitants, and that the perception of threat depends, to a certain degree, on the place of residence. The surveys also highlighted, among the other measures, solidarity and the importance of insurance against floods.

Leptospirosis following a major flood in Central Queensland, Australia.

Science.gov (United States)

Smith, J K G; Young, M M; Wilson, K L; Craig, S B

2013-03-01

Throughout December 2010 and January 2011, Queensland experienced widespread flooding due to unusually protracted and heavy rainfalls. In mid-January 2011, four individuals from a small community in Central Queensland were hospitalized with leptospirosis. A further five cases were subsequently identified from around Central Queensland, bringing the total to nine. Microscopic agglutination testing found that serovar Arborea (Leptospira borgpetersenii serovar Arborea) was presumptively responsible for leptospirosis in seven of nine confirmed cases. Serovars Hardjo and Australis were identified in samples from two remaining cases. All cases had exposure to flood water. No single exposure source was identified. This is the first reported outbreak of leptospirosis in Central Queensland and the first report of leptospirosis cases associated with flood water inundation in Queensland. Public health authorities should continue to promote awareness of leptospirosis in flood-affected populations. Healthcare providers must maintain a high level of suspicion for leptospirosis during and after flood events.

Geo-social media as a proxy for hydrometeorological data for streamflow estimation and to improve flood monitoring

Science.gov (United States)

Restrepo-Estrada, Camilo; de Andrade, Sidgley Camargo; Abe, Narumi; Fava, Maria Clara; Mendiondo, Eduardo Mario; de Albuquerque, João Porto

2018-02-01

Floods are one of the most devastating types of worldwide disasters in terms of human, economic, and social losses. If authoritative data is scarce, or unavailable for some periods, other sources of information are required to improve streamflow estimation and early flood warnings. Georeferenced social media messages are increasingly being regarded as an alternative source of information for coping with flood risks. However, existing studies have mostly concentrated on the links between geo-social media activity and flooded areas. Thus, there is still a gap in research with regard to the use of social media as a proxy for rainfall-runoff estimations and flood forecasting. To address this, we propose using a transformation function that creates a proxy variable for rainfall by analysing geo-social media messages and rainfall measurements from authoritative sources, which are later incorporated within a hydrological model for streamflow estimation. We found that the combined use of official rainfall values with the social media proxy variable as input for the Probability Distributed Model (PDM), improved streamflow simulations for flood monitoring. The combination of authoritative sources and transformed geo-social media data during flood events achieved a 71% degree of accuracy and a 29% underestimation rate in a comparison made with real streamflow measurements. This is a significant improvement on the respective values of 39% and 58%, achieved when only authoritative data were used for the modelling. This result is clear evidence of the potential use of derived geo-social media data as a proxy for environmental variables for improving flood early-warning systems.

Risk reduction by combining nature values with flood protection?

Directory of Open Access Journals (Sweden)

Van Loon-Steensma Jantsje M.

2016-01-01

foreland into the dike design does not automatically mean that nature values and flood protection are well integrated. Flood protection imposes rather different requirements on the extent and features of marshes than nature conservation and development. Wave damping is most effective with a high and stable marsh, while nature thrives with dynamic processes and differences in elevation. Therefore, only a design that allows natural marsh dynamics and includes different marsh zones could combine nature values with flood protection. In practice, this means a dike design with an uncertain foreland, that offers space for natural processes. The uncertainty in foreland development reduces the possible flood risk reduction. In our paper we describe the critical points of interest concerning risk reduction in this system.

Survey the Effects of Partial Root Zone Deficit Irrigation and Deficit Irrigation on Quantitative, Qualitative and Water Use Efficiency of Pomegranate

Directory of Open Access Journals (Sweden)

mohammad saeed tadaion

2017-12-01

Full Text Available Introduction: One of the latest efficient methods on increment of water use efficiency that confirmed by many scientists all over the world is deficit and alternative partial root zone deficit irrigation. In this experiment the effect of deficit and alternative partial root zone deficit irrigation on fruit yield, quality and water use efficiency of pomegranate (Punicagranatum (L. cv. Zarde-anar were investigatedin Arsenjan semi-arid region. Materials and Methods: The experiment was carried out in a constant plots and randomized complete block design (RCBD with four replicationsin five years.Treatmentswere 1- full flood irrigation (100 percent crop water requirement (T1 2- flood irrigation with 100 percent crop water requirement as alternate partial root-zone irrigation(every irrigation conducted on one side of tree (T2 3- flood irrigation with 50 percent crop water requirement as regular deficit irrigation (T3 4- full two-side drip irrigation(with regard to crop water requirement (eight drippers with twolit/hour flow by two different individual networks (T4 5- alternate partial root-zone drip irrigation with 100 percent crop water requirement (T5 6- regular deficit drip irrigation with 50 percent crop water requirement (T6 in every irrigation period. Each experimental treatment includes four trees and 96 similar twelve years old trees overall. Cultivation practice was conducted similarly on all of the trees. Results and Discussion: Results showed that the highest yield and water use efficiency based on statistical analysis belong to both PRD treatments i.e. alternate partial root-zone drip irrigation with 100 percent crop water requirement and alternate partial root-zone flood irrigation with 100 percent crop water requirement, respectively, that both of them decreased water requirement for irrigation up to 35 and 50 percent in comparison tocontrol. Application of partial root drying irrigation on both traditional flood irrigation and drip

Assessment of hyporheic zone, flood-plain, soil-gas, soil, and surface-water contamination at the Old Incinerator Area, Fort Gordon, Georgia, 2009-2010

Science.gov (United States)

Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the hyporheic zone, flood plain, soil gas, soil, and surface-water for contaminants at the Old Incinerator Area at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic contaminants in the hyporheic zone, flood plain, soil gas, and surface water. In addition, the organic contaminant assessment included the analysis of explosives and chemical agents in selected areas. Inorganic contaminants were assessed in soil and surface-water samples. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Total petroleum hydrocarbons were detected above the method detection level in all 13 samplers deployed in the hyporheic zone and flood plain of an unnamed tributary to Spirit Creek. The combined concentrations of benzene, toluene, ethylbenzene, and total xylene were detected at 3 of the 13 samplers. Other organic compounds detected in one sampler included octane and trichloroethylene. In the passive soil-gas survey, 28 of the 60 samplers detected total petroleum hydrocarbons above the method detection level. Additionally, 11 of the 60 samplers detected the combined masses of benzene, toluene, ethylbenzene, and total xylene above the method detection level. Other compounds detected above the method detection level in the passive soil-gas survey included octane, trimethylbenzene, perchlorethylene, and chloroform. Subsequent to the passive soil-gas survey, six areas determined to have relatively high contaminant mass were selected, and soil-gas samplers were deployed, collected, and analyzed for explosives and chemical agents. No explosives or chemical agents were detected above

2010-2011 Queensland floods: using Haddon's Matrix to define and categorise public safety strategies.

Science.gov (United States)

Zhong, Shuang; Clark, Michele; Hou, Xiang-Yu; Zang, Yu-Li; FitzGerald, Gerry

2013-08-01

The 2010-2011 Queensland floods resulted in the most deaths from a single flood event in Australia since 1916. This article analyses the information on these deaths for comparison with those from previous floods in modern Australia in an attempt to identify factors that have contributed to those deaths. Haddon's Matrix, originally designed for prevention of road trauma, offers a framework for understanding the interplay between contributing factors and helps facilitate a clearer understanding of the varied strategies required to ensure people's safety for particular flood types. Public reports and flood relevant literature were searched using key words 'flood', 'fatality', 'mortality', 'death', 'injury' and 'victim' through Google Scholar, PubMed, ProQuest and EBSCO. Data relating to reported deaths during the 2010-2011 Queensland floods, and relevant data of previous Australian flood fatality (1997-2009) were collected from these available sources. These sources were also used to identify contributing factors. There were 33 deaths directly attributed to the event, of which 54.5% were swept away in a flash flood on 10 January 2011. A further 15.1% of fatalities were caused by inappropriate behaviours. This is different to floods in modern Australia where over 90% of deaths are related to the choices made by individuals. There is no single reason why people drown in floods, but rather a complex interplay of factors. The present study and its integration of research findings and conceptual frameworks might assist governments and communities to develop policies and strategies to prevent flood injury and fatalities. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Taxation records as a source of information for the study of historical floods in South Moravia, Czech Republic

Science.gov (United States)

Brázdil, R.; Chromá, K.; Řezníčková, L.; Valášek, H.; Dolák, L.; Stachoň, Z.; Soukalová, E.; Dobrovolný, P.

2014-07-01

Since the second half of the 17th century, tax relief has been available to farmers and landowners to offset flood damage to property (buildings) and land (fields, meadows, pastures, gardens) in South Moravia, Czech Republic. Historically, the written applications for this were supported by a relatively efficient bureaucratic process that left a clear data trail of documentation, preserved at several levels: in the communities affected, in regional offices, and in the Moravian Land Office, all of which are to be found in estate and family collections in the Moravian Land Archives in the city of Brno, the provincial capital. As well as detailed information about damage done and administrative responses to it, data is often preserved as to the flood event itself, the time of its occurrence and its impacts, sometimes together with causes and stages. The final flood database based on taxation records is used here to describe the temporal and spatial density of both flood events and the records themselves. The information derived is used to help create long-term flood chronologies for the Rivers Dyje, Jihlava, Svratka and Morava, combining floods interpreted from taxation records with other documentary data and floods derived from later systematic hydrological measurements (water levels, discharges). Common periods of higher flood frequency appear largely in 1821-1850 and 1921-1950, although this shifts to several other decades for individual rivers. Certain uncertainties are inseparable from flood data taxation records: their spatial and temporal incompleteness; the inevitable limitation to larger-scale damage and to the summer half-year; and the different characters of rivers, including land-use changes and channel modifications. Taxation data has great potential for extending our knowledge of past floods for the rest of the Czech Republic as well, not to mention other European countries in which records have survived.

Voice-enabled Knowledge Engine using Flood Ontology and Natural Language Processing

Science.gov (United States)

Sermet, M. Y.; Demir, I.; Krajewski, W. F.

2015-12-01

The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts, flood-related data, information and interactive visualizations for communities in Iowa. The IFIS is designed for use by general public, often people with no domain knowledge and limited general science background. To improve effective communication with such audience, we have introduced a voice-enabled knowledge engine on flood related issues in IFIS. Instead of navigating within many features and interfaces of the information system and web-based sources, the system provides dynamic computations based on a collection of built-in data, analysis, and methods. The IFIS Knowledge Engine connects to real-time stream gauges, in-house data sources, analysis and visualization tools to answer natural language questions. Our goal is the systematization of data and modeling results on flood related issues in Iowa, and to provide an interface for definitive answers to factual queries. The goal of the knowledge engine is to make all flood related knowledge in Iowa easily accessible to everyone, and support voice-enabled natural language input. We aim to integrate and curate all flood related data, implement analytical and visualization tools, and make it possible to compute answers from questions. The IFIS explicitly implements analytical methods and models, as algorithms, and curates all flood related data and resources so that all these resources are computable. The IFIS Knowledge Engine computes the answer by deriving it from its computational knowledge base. The knowledge engine processes the statement, access data warehouse, run complex database queries on the server-side and return outputs in various formats. This presentation provides an overview of IFIS Knowledge Engine, its unique information interface and functionality as an educational tool, and discusses the future plans

Flash floods in Europe: state of the art and research perspectives

Science.gov (United States)

Gaume, Eric

2014-05-01

Flash floods, i.e. floods induced by severe rainfall events generally affecting watersheds of limited area, are the most frequent, destructive and deadly kind of natural hazard known in Europe and throughout the world. Flash floods are especially intense across the Mediterranean zone, where rainfall accumulations exceeding 500 mm within a few hours may be observed. Despite this state of facts, the study of extremes in hydrology has essentially gone unexplored until the recent past, with the exception of some rare factual reports on individual flood events, with the sporadic inclusion of isolated estimated peak discharges. Floods of extraordinary magnitude are in fact hardly ever captured by existing standard measurement networks, either because they are too heavily concentrated in space and time or because their discharges greatly exceed the design and calibration ranges of the measurement devices employed (stream gauges). This situation has gradually evolved over the last decade for two main reasons. First, the expansion and densification of weather radar networks, combined with improved radar quantitative precipitation estimates, now provide ready access to rainfall measurements at spatial and temporal scales that, while not perfectly accurate, are compatible with the study of extreme events. Heavy rainfall events no longer fail to be recorded by existing rain gauge and radar networks. Second, pioneering research efforts on extreme floods, based on precise post-flood surveys, have helped overcome the limitations imposed by a small base of available direct measured data. This activity has already yielded significant progress in expanding the knowledge and understanding of extreme flash floods. This presentation will provide a review of the recent research progresses in the area of flash flood studies, mainly based on the outcomes of the European research projects FLOODsite, HYDRATE and Hymex. It will show how intensive collation of field data helped better define

Geohazards (floods and landslides in the Ndop plain, Cameroon volcanic line

Directory of Open Access Journals (Sweden)

Wotchoko Pierre

2016-07-01

Full Text Available The Ndop Plain, located along the Cameroon Volcanic Line (CVL, is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually and landslides (occasionally occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered.

76 FR 35104 - Safety Zone; Waterway Closure, Atchafalaya River From Mile Marker 117 (Morgan City Railroad...

Science.gov (United States)

2011-06-16

...-AA00 Safety Zone; Waterway Closure, Atchafalaya River From Mile Marker 117 (Morgan City Railroad Bridge... with rising flood water in the Atchafalaya River. Basis and Purpose Captain of the Port Morgan City... safety zone is located on the specified waters of the Atchafalaya River between MM 117 (Morgan City...

Mapping flood hazards under uncertainty through probabilistic flood inundation maps

Science.gov (United States)

Stephens, T.; Bledsoe, B. P.; Miller, A. J.; Lee, G.

2017-12-01

Changing precipitation, rapid urbanization, and population growth interact to create unprecedented challenges for flood mitigation and management. Standard methods for estimating risk from flood inundation maps generally involve simulations of floodplain hydraulics for an established regulatory discharge of specified frequency. Hydraulic model results are then geospatially mapped and depicted as a discrete boundary of flood extents and a binary representation of the probability of inundation (in or out) that is assumed constant over a project's lifetime. Consequently, existing methods utilized to define flood hazards and assess risk management are hindered by deterministic approaches that assume stationarity in a nonstationary world, failing to account for spatio-temporal variability of climate and land use as they translate to hydraulic models. This presentation outlines novel techniques for portraying flood hazards and the results of multiple flood inundation maps spanning hydroclimatic regions. Flood inundation maps generated through modeling of floodplain hydraulics are probabilistic reflecting uncertainty quantified through Monte-Carlo analyses of model inputs and parameters under current and future scenarios. The likelihood of inundation and range of variability in flood extents resulting from Monte-Carlo simulations are then compared with deterministic evaluations of flood hazards from current regulatory flood hazard maps. By facilitating alternative approaches of portraying flood hazards, the novel techniques described in this presentation can contribute to a shifting paradigm in flood management that acknowledges the inherent uncertainty in model estimates and the nonstationary behavior of land use and climate.

STUDY REGARDING DELINEATION OF FLOOD HAZARD ZONES IN THE HYDROGRAPHIC BASIN OF THE SOMEŞ RIVER, BORDER AREA

OpenAIRE

STOICA F.; ROŞU I.; SOFRONIE C.; DULĂU R.; SÂRB M.

2014-01-01

The hydrological studies will provide the characteristic parameters for the floods occurred for the calculus discharges with overflow probabilities of 0,1%; 1%, 5%, 10%. The hydrologic and hydraulic models will be made by using the hydro-meteorological data base and the topographical measurements on site; them calibration will be done according to the records of the historical floods. The studies on the hydrologic and hydraulic models will be necessary for the establishment of the carrying ca...

Assessing lateral flows and solute transport during floods in a conduit-flow-dominated karst system using the inverse problem for the advection-diffusion equation

Science.gov (United States)

Cholet, Cybèle; Charlier, Jean-Baptiste; Moussa, Roger; Steinmann, Marc; Denimal, Sophie

2017-07-01

The aim of this study is to present a framework that provides new ways to characterize the spatio-temporal variability of lateral exchanges for water flow and solute transport in a karst conduit network during flood events, treating both the diffusive wave equation and the advection-diffusion equation with the same mathematical approach, assuming uniform lateral flow and solute transport. A solution to the inverse problem for the advection-diffusion equations is then applied to data from two successive gauging stations to simulate flows and solute exchange dynamics after recharge. The study site is the karst conduit network of the Fourbanne aquifer in the French Jura Mountains, which includes two reaches characterizing the network from sinkhole to cave stream to the spring. The model is applied, after separation of the base from the flood components, on discharge and total dissolved solids (TDSs) in order to assess lateral flows and solute concentrations and compare them to help identify water origin. The results showed various lateral contributions in space - between the two reaches located in the unsaturated zone (R1), and in the zone that is both unsaturated and saturated (R2) - as well as in time, according to hydrological conditions. Globally, the two reaches show a distinct response to flood routing, with important lateral inflows on R1 and large outflows on R2. By combining these results with solute exchanges and the analysis of flood routing parameters distribution, we showed that lateral inflows on R1 are the addition of diffuse infiltration (observed whatever the hydrological conditions) and localized infiltration in the secondary conduit network (tributaries) in the unsaturated zone, except in extreme dry periods. On R2, despite inflows on the base component, lateral outflows are observed during floods. This pattern was attributed to the concept of reversal flows of conduit-matrix exchanges, inducing a complex water mixing effect in the saturated zone

Assessing lateral flows and solute transport during floods in a conduit-flow-dominated karst system using the inverse problem for the advection–diffusion equation

Directory of Open Access Journals (Sweden)

C. Cholet

2017-07-01

Full Text Available The aim of this study is to present a framework that provides new ways to characterize the spatio-temporal variability of lateral exchanges for water flow and solute transport in a karst conduit network during flood events, treating both the diffusive wave equation and the advection–diffusion equation with the same mathematical approach, assuming uniform lateral flow and solute transport. A solution to the inverse problem for the advection–diffusion equations is then applied to data from two successive gauging stations to simulate flows and solute exchange dynamics after recharge. The study site is the karst conduit network of the Fourbanne aquifer in the French Jura Mountains, which includes two reaches characterizing the network from sinkhole to cave stream to the spring. The model is applied, after separation of the base from the flood components, on discharge and total dissolved solids (TDSs in order to assess lateral flows and solute concentrations and compare them to help identify water origin. The results showed various lateral contributions in space – between the two reaches located in the unsaturated zone (R1, and in the zone that is both unsaturated and saturated (R2 – as well as in time, according to hydrological conditions. Globally, the two reaches show a distinct response to flood routing, with important lateral inflows on R1 and large outflows on R2. By combining these results with solute exchanges and the analysis of flood routing parameters distribution, we showed that lateral inflows on R1 are the addition of diffuse infiltration (observed whatever the hydrological conditions and localized infiltration in the secondary conduit network (tributaries in the unsaturated zone, except in extreme dry periods. On R2, despite inflows on the base component, lateral outflows are observed during floods. This pattern was attributed to the concept of reversal flows of conduit–matrix exchanges, inducing a complex water mixing effect

INFLUENCE OF DEM IN WATERSHED MANAGEMENT AS FLOOD ZONATION MAPPING

Directory of Open Access Journals (Sweden)

M. Alrajhi

2016-06-01

Full Text Available Despite of valuable efforts from working groups and research organizations towards flood hazard reduction through its program, still minimal diminution from these hazards has been realized. This is mainly due to the fact that with rapid increase in population and urbanization coupled with climate change, flood hazards are becoming increasingly catastrophic. Therefore there is a need to understand and access flood hazards and develop means to deal with it through proper preparations, and preventive measures. To achieve this aim, Geographical Information System (GIS, geospatial and hydrological models were used as tools to tackle with influence of flash floods in the Kingdom of Saudi Arabia due to existence of large valleys (Wadis which is a matter of great concern. In this research paper, Digital Elevation Models (DEMs of different resolution (30m, 20m,10m and 5m have been used, which have proven to be valuable tool for the topographic parameterization of hydrological models which are the basis for any flood modelling process. The DEM was used as input for performing spatial analysis and obtaining derivative products and delineate watershed characteristics of the study area using ArcGIS desktop and its Arc Hydro extension tools to check comparability of different elevation models for flood Zonation mapping. The derived drainage patterns have been overlaid over aerial imagery of study area, to check influence of greater amount of precipitation which can turn into massive destructions. The flow accumulation maps derived provide zones of highest accumulation and possible flow directions. This approach provide simplified means of predicting extent of inundation during flood events for emergency action especially for large areas because of large coverage area of the remotely sensed data.

Flood Risk Management In Europe: European flood regulation

NARCIS (Netherlands)

Hegger, D.L.T.; Bakker, M.H.; Green, C.; Driessen, Peter; Delvaux, B.; Rijswick, H.F.M.W. van; Suykens, C.; Beyers, J-C.; Deketelaere, K.; Doorn-Hoekveld, W. van; Dieperink, C.

2013-01-01

In Europe, water management is moving from flood defense to a risk management approach, which takes both the probability and the potential consequences of flooding into account. In this report, we will look at Directives and (non-)EU- initiatives in place to deal with flood risk in Europe indirectly

Citizen involvement in flood risk governance: flood groups and networks

Directory of Open Access Journals (Sweden)

Twigger-Ross Clare

2016-01-01

Full Text Available Over the past decade has been a policy shift withinUK flood risk management towards localism with an emphasis on communities taking ownership of flood risk. There is also an increased focus on resilience and, more specifically, on community resilience to flooding. This paper draws on research carried out for UK Department for Environment Food and Rural Affairs to evaluate the Flood Resilience Community Pathfinder (FRCP scheme in England. Resilience is conceptualised as multidimensional and linked to exisiting capacities within a community. Creating resilience to flooding is an ongoing process of adaptation, learning from past events and preparing for future risks. This paper focusses on the development of formal and informal institutions to support improved flood risk management: institutional resilience capacity. It includes new institutions: e.g. flood groups, as well as activities that help to build inter- and intra- institutional resilience capacity e.g. community flood planning. The pathfinder scheme consisted of 13 projects across England led by local authorities aimed at developing community resilience to flood risk between 2013 – 2015. This paper discusses the nature and structure of flood groups, the process of their development, and the extent of their linkages with formal institutions, drawing out the barriers and facilitators to developing institutional resilience at the local level.

137Cs contamination of the Techa river flood plain near the village of Muslumovo

International Nuclear Information System (INIS)

Chesnokov, A.V.; Govorun, A.P.; Linnik, V.G.; Shcherbak, S.B.

2000-01-01

The results of a radiometric survey of the Techa river flood plain near the village of Muslumovo in the Chelyabinsk region of Russia are presented. The observed territory extended 16.6 km along the riverbed, with a total area of 2.5 km 2 . The collimated scintillation detector technique was applied to in situ field measurements of 137 Cs deposition on the soil. Maps of 137 Cs deposition and soil penetration depth were developed on the basis of approximately 5000 measurements. The total 137 Cs deposition within the surveyed territory has been estimated at 6.6 TBq. The means of the total 137 Cs soil depositions at half-kilometer sites on the flood plain and its distribution along the river have also been calculated. A maximum 137 Cs contamination above 7.5 MBq/m 2 is associated with a bank height up to 1 m above the usual water level. The data identify zones of intensive radionuclide sedimentation and transit zones

Assessment of Hyporheic Zone, Flood-Plain, Soil-Gas, Soil, and Surface-Water Contamination at the McCoys Creek Chemical Training Area, Fort Gordon, Georgia, 2009-2010

Science.gov (United States)

Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the hyporheic zone, flood plain, soil gas, soil, and surface water for contaminants at the McCoys Creek Chemical Training Area (MCTA) at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic contaminants in the hyporheic zone, flood plain, soil gas, and surface water. In addition, the organic contaminant assessment included the analysis of organic compounds classified as explosives and chemical agents in selected areas. Inorganic contaminants were assessed in soil and surface-water samples. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Ten passive samplers were deployed in the hyporheic zone and flood plain, and total petroleum hydrocarbons (TPH) and octane were detected above the method detection level in every sampler. Other organic compounds detected above the method detection level in the hyporheic zone and flood-plain samplers were trichloroethylene, and cis- and trans- 1, 2-dichloroethylene. One trip blank detected TPH below the method detection level but above the nondetection level. The concentrations of TPH in the samplers were many times greater than the concentrations detected in the blank; therefore, all other TPH concentrations detected are considered to represent environmental conditions. Seventy-one soil-gas samplers were deployed in a grid pattern across the MCTA. Three trip blanks and three method blanks were used and not deployed, and TPH was detected above the method detection level in two trip blanks and one method blank. Detection of TPH was observed at all 71 samplers, but because TPH was detected in the trip and method blanks, TPH was

A modeling study of water flow in the vadose zone beneath the Radioactive Waste Management Complex

International Nuclear Information System (INIS)

Baca, R.G.; Magnuson, S.O.; Nguyen, H.D.; Martian, P.

1992-01-01

A modeling study was conducted for the purpose of gaining insight into the nature of water flow in the vadose zone beneath the Radioactive Waste Management Complex (RWMC). The modeling study focused on three specific hydrologic aspects: (1) relationship between meteorologic conditions and net infiltration, (2) water movement associated with past flooding events, and (3) estimation of water travel-times through the vadose zone. This information is necessary for understanding how contaminants may be transported through the vadose zone. Evaluations of net infiltration at the RWMC were performed by modeling the processes of precipitation, evaporation, infiltration and soil-moisture redistribution. Water flow simulations were performed for two distinct time periods, namely 1955--1964 and 1984--1990. The patterns of infiltration were calculated for both the undisturbed (or natural sediments) and the pit/trench cover materials. Detailed simulations of the 1969 flooding of Pit 10 were performed to estimate the rate and extent of water movement through the vadose zone. Water travel-times through the vadose zone were estimated using a Monte Carlo simulation approach. The simulations accounted for variability of soil and rock hydraulic properties as well as variations in the infiltration rate

Hydrodynamic modelling of extreme flood events in the Kashmir valley in India

Science.gov (United States)

Jain, Manoj; Parvaze, Sabah

2017-04-01

Floods are one of the most predominant, costly and deadly hazards of all natural vulnerabilities. Every year, floods exert a heavy toll on human life and property in many parts of the world. The prediction of river stages and discharge during flood extremes plays a vital role in planning structural and non-structural measures of flood management. The predictions are also valuable to prepare the flood inundation maps and river floodplain zoning. In the Kashmir Valley, floods occur mainly and very often in the Jhelum Basin mostly due to extreme precipitation events and rugged mountainous topography of the basin. These floods cause extreme damage to life and property in the valley from time to time. Excessive rainfall, particularly in higher sub-catchments causes the snow to melt resulting in excessive runoff downhill to the streams causing floods in the Kashmir Valley where Srinagar city is located. However, very few hydrological studies have been undertaken for the Jhelum Basin mainly due to non-availability of hydrological data due to very complex mountainous terrain. Therefore, the present study has been conducted to model the extreme flood events in the Jhelum Basin in Kashmir Valley. An integrated NAM and MIKE 11 HD model has been setup for Jhelum basin up to Ram Munshi Bagh gauging site and then four most extreme historical flood events in the time series has been analyzed separately including the most recent and most extreme flood event of 2014. In September 2014, the Kashmir Valley witnessed the most severe flood in the past 60 years due to catastrophic rainfall from 1st to 6th September wherein the valley received unprecedented rainfall of more than 650 mm in just 3 days breaking record of many decades. The MIKE 11 HD and NAM model has been calibrated using 21 years (1985-2005) data and validated using 9 years (2006-2014) data. The efficiency indices of the model for calibration and validation period is 0.749 and 0.792 respectively. The model simulated

Nitrate removal in a restored riparian groundwater system: functioning and importance of individual riparian zones

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S. Peter

2012-11-01

Full Text Available For the design and the assessment of river restoration projects, it is important to know to what extent the elimination of reactive nitrogen (N can be improved in the riparian groundwater. We investigated the effectiveness of different riparian zones, characterized by a riparian vegetation succession, for nitrate (NO₃⁻ removal from infiltrating river water in a restored and a still channelized section of the river Thur, Switzerland. Functional genes of denitrification (nirS and nosZ were relatively abundant in groundwater from willow bush and mixed forest dominated zones, where oxygen concentrations remained low compared to the main channel and other riparian zones. After flood events, a substantial decline in NO₃⁻ concentration (> 50% was observed in the willow bush zone but not in the other riparian zones closer to the river. In addition, the characteristic enrichment of ¹⁵N and ¹⁸O in the residual NO₃⁻ pool (by up to 22‰ for δ¹⁵N and up to 12‰ for δ¹⁸O provides qualitative evidence that the willow bush and forest zones were sites of active denitrification and, to a lesser extent, NO₃⁻ removal by plant uptake. Particularly in the willow bush zone during a period of water table elevation after a flooding event, substantial input of organic carbon into the groundwater occurred, thereby fostering post-flood denitrification activity that reduced NO₃⁻ concentration with a rate of ~21 μmol N l⁻¹ d⁻¹. Nitrogen removal in the forest zone was not sensitive to flood pulses, and overall NO₃⁻ removal rates were lower (~6 μmol l⁻¹ d⁻¹. Hence, discharge-modulated vegetation–soil–groundwater coupling was found to be a key driver for riparian NO₃⁻ removal. We estimated that

Uncertainty Analysis of A Flood Risk Mapping Procedure Applied In Urban Areas

Science.gov (United States)

Krause, J.; Uhrich, S.; Bormann, H.; Diekkrüger, B.

In the framework of IRMA-Sponge program the presented study was part of the joint research project FRHYMAP (flood risk and hydrological mapping). A simple con- ceptual flooding model (FLOODMAP) has been developed to simulate flooded areas besides rivers within cities. FLOODMAP requires a minimum of input data (digital el- evation model (DEM), river line, water level plain) and parameters and calculates the flood extent as well as the spatial distribution of flood depths. of course the simulated model results are affected by errors and uncertainties. Possible sources of uncertain- ties are the model structure, model parameters and input data. Thus after the model validation (comparison of simulated water to observed extent, taken from airborne pictures) the uncertainty of the essential input data set (digital elevation model) was analysed. Monte Carlo simulations were performed to assess the effect of uncertain- ties concerning the statistics of DEM quality and to derive flooding probabilities from the set of simulations. The questions concerning a minimum resolution of a DEM re- quired for flood simulation and concerning the best aggregation procedure of a given DEM was answered by comparing the results obtained using all available standard GIS aggregation procedures. Seven different aggregation procedures were applied to high resolution DEMs (1-2m) in three cities (Bonn, Cologne, Luxembourg). Basing on this analysis the effect of 'uncertain' DEM data was estimated and compared with other sources of uncertainties. Especially socio-economic information and monetary transfer functions required for a damage risk analysis show a high uncertainty. There- fore this study helps to analyse the weak points of the flood risk and damage risk assessment procedure.

Flood-rich and flood-poor periods in Spain in 1942-2009

Science.gov (United States)

Mediero, Luis; Santillán, David; Garrote, Luis

2016-04-01

Several studies to detect trends in flood series at either national or trans-national scales have been conducted. Mediero et al. (2015) studied flood trends by using the longest streamflow records available in Europe. They found a decreasing trend in the Atlantic, Continental and Scandinavian regions. More specifically, Mediero et al. (2014) found a general decreasing trend in flood series in Spain in the period 1959-2009. Trends in flood series are usually detected by the Mann-Kendall test applied to a given period. However, the result of the Mann-Kendall test can change in terms of the starting and ending year of the series. Flood oscillations can occur and flood-rich and flood-poor periods could condition the results, especially when they are located at the beginning or end of the series. A methodology to identify statistically significant flood-rich and flood-poor periods is developed, based on the comparison between the expected sampling variability of floods when stationarity is assumed and the observed variability of floods in a given series. The methodology is applied to the longest series of annual maximum floods, peaks over threshold and counts of annual occurrences in peaks over threshold series observed in Spain in the period 1942-2009. A flood-rich period in 1950-1970 and a flood-poor period in 1970-1990 are identified in most of the selected sites. The generalised decreasing trend in flood series found by Mediero et al. (2014) could be explained by a flood-rich period placed at the beginning of the series and a flood-poor period located at the end of the series. References: Mediero, L., Kjeldsen, T.R., Macdonald, N., Kohnova, S., Merz, B., Vorogushyn, S., Wilson, D., Alburquerque, T., Blöschl, G., Bogdanowicz, E., Castellarin, A., Hall, J., Kobold, M., Kriauciuniene, J., Lang, M., Madsen, H., Onuşluel Gül, G., Perdigão, R.A.P., Roald, L.A., Salinas, J.L., Toumazis, A.D., Veijalainen, N., Óðinn Þórarinsson. Identification of coherent flood

Recent advances in flood forecasting and flood risk assessment

Directory of Open Access Journals (Sweden)

G. Arduino

2005-01-01

Full Text Available Recent large floods in Europe have led to increased interest in research and development of flood forecasting systems. Some of these events have been provoked by some of the wettest rainfall periods on record which has led to speculation that such extremes are attributable in some measure to anthropogenic global warming and represent the beginning of a period of higher flood frequency. Whilst current trends in extreme event statistics will be difficult to discern, conclusively, there has been a substantial increase in the frequency of high floods in the 20th century for basins greater than 2x105 km2. There is also increasing that anthropogenic forcing of climate change may lead to an increased probability of extreme precipitation and, hence, of flooding. There is, therefore, major emphasis on the improvement of operational flood forecasting systems in Europe, with significant European Community spending on research and development on prototype forecasting systems and flood risk management projects. This Special Issue synthesises the most relevant scientific and technological results presented at the International Conference on Flood Forecasting in Europe held in Rotterdam from 3-5 March 2003. During that meeting 150 scientists, forecasters and stakeholders from four continents assembled to present their work and current operational best practice and to discuss future directions of scientific and technological efforts in flood prediction and prevention. The papers presented at the conference fall into seven themes, as follows.

A sequential model to link contextual risk, perception and public support for flood adaptation policy.

Science.gov (United States)

Shao, Wanyun; Xian, Siyuan; Lin, Ning; Small, Mitchell J

2017-10-01

The economic damage from coastal flooding has dramatically increased over the past several decades, owing to rapid development in shoreline areas and possible effects of climate change. To respond to these trends, it is imperative for policy makers to understand individuals' support for flood adaptation policy. Using original survey data for all coastal counties of the United States Gulf Coast merged with contextual data on flood risk, this study investigates coastal residents' support for two adaptation policy measures: incentives for relocation and funding for educational programs on emergency planning and evacuation. Specifically, this study explores the interactive relationships among contextual flood risks, perceived flood risks and policy support for flood adaptation, with the effects of social-demographic variables being controlled. Age, gender, race and partisanship are found to significantly affect individuals' policy support for both adaptation measures. The contextual flooding risks, indicated by distance from the coast, maximum wind speed and peak height of storm surge associated with the last hurricane landfall, and percentage of high-risk flood zone per county, are shown to impact one's perceptions of risk, which in turn influence one's support for both policy measures. The key finding -risk perception mediates the impact of contextual risk conditions on public support for flood management policies - highlights the need to ensure that the public is well informed by the latest scientific, engineering and economic knowledge. To achieve this, more information on current and future flood risks and options available for mitigation as well as risk communication tools are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

A bottom up approach to implementing multi-purpose mitigation measures for reducing flood risk and improving water quality in agricultural catchments

Science.gov (United States)

Wilkinson, M. E.; Quinn, P. F.; Jonczyk, J.; Burke, S.; Nicholson, A.; Barber, N.; Owen, G.; Palmer, M.

2012-04-01

A number of studies have suggested that there is evidence that modern land-use management practices have increased surface runoff at the local scale. There is an urgent need for interventions to reduce the risk of flooding whilst also delivering multiple benefits (doing more for less). There are many settlements, which regularly suffer from flooding, which would benefit from upstream mitigation measures. Interventions at the source of runoff generation can have a positive impact on the flood hydrograph downstream. An integrated approach to managing runoff can also have multiple benefits on pollution and ecology, which could lead to beneficial impacts at the catchment scale. Belford, a small community in Northumberland, UK has suffered from an increased number of flood events over the past ten years. There is currently support within the English and Welsh Environment Agency for sustainable flood management solutions such as storage ponds, wetlands, beaver dams and willow riparian features which are being trialled at Belford. These runoff attenuation features (RAFs) also have benefits to water quality, capture sediment and create new ecological zones. Although the process by which numerous RAFs were deployed in Belford proved initially difficult to achieve within the existing regulatory framework, an efficient uptake process is now supported by local regulators including several branches of the Environment Agency. The Belford runoff management framework provides a step by step guide to implementing mitigation measures in the Belford burn catchment and could be easily applied to other catchments at a similar scale. The approach is based on implementing mitigation measures through engaging with catchment stakeholders and using solid field science and management protocols.

Effects of flooding and aging on phytoremediation of typical polycyclic aromatic hydrocarbons in mangrove sediments by Kandelia obovata seedlings.

Science.gov (United States)

Li, Rui-Long; Liu, Bei-Bei; Zhu, Ya-Xian; Zhang, Yong

2016-06-01

A laboratory experiment was conducted to evaluate the effects of flooding and aging on the phytoremediation of naphthalene (Nap), anthracene (Ant) and benzo[a]pyrene (B[a]P) in mangrove sediment by Kandelia obovata (K. obovata) Druce seedlings. Flooding increased dissipation efficiency in the rhizosphere zone from 69.47% to 82.45%, 64.27% to 80.41%, and 61.55% to 78.31% for Nap, Ant and B[a]P, respectively. Aging decreased dissipation efficiency significantly. Further investigation demonstrated that increased enzyme activity was one of important factors for increasing PAHs dissipation rates in flooded mangrove sediments. Moreover, a novel method for in situ quantitative investigation of PAHs distribution in root tissues was established using microscopic fluorescence spectra analysis. Subsequently, the effects of flooding and aging on the distribution of PAHs in root tissues were evaluated using this established method. The order of bioavailable fractions of PAHs after phytoremediation was as follows: non-aging/non-flooding>flooding>aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Rethinking the relationship between flood risk perception and flood management.

Science.gov (United States)

Birkholz, S; Muro, M; Jeffrey, P; Smith, H M

2014-04-15

Although flood risk perceptions and their concomitant motivations for behaviour have long been recognised as significant features of community resilience in the face of flooding events, there has, for some time now, been a poorly appreciated fissure in the accompanying literature. Specifically, rationalist and constructivist paradigms in the broader domain of risk perception provide different (though not always conflicting) contexts for interpreting evidence and developing theory. This contribution reviews the major constructs that have been applied to understanding flood risk perceptions and contextualises these within broader conceptual developments around risk perception theory and contemporary thinking around flood risk management. We argue that there is a need to re-examine and re-invigorate flood risk perception research, in a manner that is comprehensively underpinned by more constructivist thinking around flood risk management as well as by developments in broader risk perception research. We draw attention to an historical over-emphasis on the cognitive perceptions of those at risk to the detriment of a richer understanding of a wider range of flood risk perceptions such as those of policy-makers or of tax-payers who live outside flood affected areas as well as the linkages between these perspectives and protective measures such as state-supported flood insurance schemes. Conclusions challenge existing understandings of the relationship between risk perception and flood management, particularly where the latter relates to communication strategies and the extent to which those at risk from flooding feel responsible for taking protective actions. Copyright © 2014 Elsevier B.V. All rights reserved.

The Impacts of Episodic Storm and Flood Events on Carbon and Sediment Delivery to Gulf of Mexico Sediments

Science.gov (United States)

Schreiner, K. M.; Carlin, J. A.; Sayers, L.; Swenson, J.

2017-12-01

Marine sediments are an important long-term reservoir for both recently fixed organic carbon (OC) and ancient rock derived OC, much of which is delivered by rivers. The ratio between these two sources of OC in turn regulates atmospheric levels of oxygen and carbon dioxide over geologic time, making this riverine delivery of OC, primarily carried by sediments, an important flux in the global carbon cycle. However, while the overall magnitude of these fluxes are relatively well known, it remains to be determined the importance of episodic events, like storms and floods, in the flux of OC from terrestrial to marine environments. Here, we present data from a 34 cm core collected from the Gulf of Mexico at a mid-shelf distal depocenter for the Brazos River in 2015, during a strong El Nino when that area of the country was experiencing 100-year flood events and anomalously high river flow. Based on analysis of the radioactive isotope 7Be, approximately the top 7-8 cm of the sediment in this core was deposited during this flood event. Both bulk elemental (C, N, and stable carbon isotopes) and chemical biomarker (lignin-phenol) data has been combined to provide information of the origin and chemistry of the OC in this core both before and during flooding. C:N and d13C indicate a mixture of marine-sourced and terrestrially-sourced OC throughout the length of the core with very little variation between the flood layer and deeper sediments. However, lignin-phenol concentrations are higher in flood-deposited sediment, indicating that this sediment is likely terrestrially-sourced. Lignin-phenol indicators of OC degradation state (Acid:Aldehyde ratios) indicate that flood sediment is fresher and less degraded than deeper sediments. Taken together, these results indicate that 1. Bulk analyses are not enough to determine OC source and the importance of flood events in OC cycling and 2. Episodic events like floods could have an oversized impact on OC storage in marine sediments.

Flood Risk, Flood Mitigation, and Location Choice: Evaluating the National Flood Insurance Program's Community Rating System.

Science.gov (United States)

Fan, Qin; Davlasheridze, Meri

2016-06-01

Climate change is expected to worsen the negative effects of natural disasters like floods. The negative impacts, however, can be mitigated by individuals' adjustments through migration and relocation behaviors. Previous literature has identified flood risk as one significant driver in relocation decisions, but no prior study examines the effect of the National Flood Insurance Program's voluntary program-the Community Rating System (CRS)-on residential location choice. This article fills this gap and tests the hypothesis that flood risk and the CRS-creditable flood control activities affect residential location choices. We employ a two-stage sorting model to empirically estimate the effects. In the first stage, individuals' risk perception and preference heterogeneity for the CRS activities are considered, while mean effects of flood risk and the CRS activities are estimated in the second stage. We then estimate heterogeneous marginal willingness to pay (WTP) for the CRS activities by category. Results show that age, ethnicity and race, educational attainment, and prior exposure to risk explain risk perception. We find significant values for the CRS-creditable mitigation activities, which provides empirical evidence for the benefits associated with the program. The marginal WTP for an additional credit point earned for public information activities, including hazard disclosure, is found to be the highest. Results also suggest that water amenities dominate flood risk. Thus, high amenity values may increase exposure to flood risk, and flood mitigation projects should be strategized in coastal regions accordingly. © 2015 Society for Risk Analysis.

RISK VIP: Evaluation of Flood Risk on the French Railway Network Using an Innovative GIS Approach

Directory of Open Access Journals (Sweden)

Cheetham Mark

2016-01-01

Full Text Available Flooding can have significant direct and indirect negative effects on a railway network affecting both infrastructure and rail operations. Such impacts include the delaying or cancelling of train services, damage to railway structures or the implementation of costly maintenance and monitoring programs to ensure the safety and performance of the railway system. Identifying sections of railway line at risk from flooding allows appropriate actions to be targeted at specific areas and contributes to an effective asset management plan. Flooding of railway infrastructure can have numerous sources including surface water run-off, insufficient capacity of hydraulic structures or the inundation of embankments located in floodplains. Consequences of flooding include the destabilisation of structures (surface erosion of embankments or the undermining of bridge foundations, differential settlement of structures and damage to the track structure. This paper details an innovative approach developed at the SNCF using a Geographic Information System (GIS model to identify zones of the railway network at risk of different types of flooding. The GIS model RiskVIP has been constructed through the assessment of three distinct components of risk: “Vulnerability” (assessment of the susceptibility of the railway infrastructure to flood conditions, Intensity’ (capacity of a catchment to generate a flood flow, Probability’ (probability of a rainfall event.Through the application of decision trees, the component ‘Intensity’ has been characterised in the model by the physical properties of the catchment intercepted by the railway line (surface area of the catchment, slope and land cover characteristics and “Vulnerability” by the infrastructure itself (type, geometry and the presence of hydraulic structures. In order to evaluate its efficiency at identifying sites at risk of flooding, the model has been tested in the region of Languedoc-Roussillon in France

May flood-poor periods be more dangerous than flood-rich periods?

Science.gov (United States)

Salinas, Jose Luis; Di Baldassarre, Giuliano; Viglione, Alberto; Kuil, Linda; Bloeschl, Guenter

2014-05-01

River floods are among the most devastating natural hazards experienced by populations that, since the earliest recorded civilisations, have settled in floodplains because they offer favourable conditions for trade, agriculture, and economic development. The occurrence of a flood may cause loss of lives and tremendous economic damages and, therefore, is rightly seen as a very negative event by the communities involved. Occurrence of many floods in a row is, of course, even more frustrating and is rightly considered a unbearable calamity. Unfortunately, the occurrence of many floods in a limited number of consecutive years is not unusual. In many places in the world, it has been observed that extreme floods do not arrive randomly but cluster in time into flood-poor and flood-rich periods consistent with the Hurst effect. If this is the case, when are the people more in danger? When should people be more scared? In flood-poor or flood-rich periods? In this work, a Socio-Hydrology model (Di Baldassarre et al., 2013; Viglione et al., 2014) is used to show that, maybe counter-intuitively, flood-poor periods may be more dangerous than flood-rich periods. The model is a conceptualisation of a hypothetical setting of a city at a river where a community evolves, making choices between flood management options on the floodplain. The most important feedbacks between the economic, political, technological and hydrological processes of the evolution of that community are represented in the model. In particular, the model also accounts in a dynamic way for the evolution of the the community awareness to flood risk. Occurrence of floods tends to increase peoples' recognition that their property is in an area that is potentially at risk of flooding, both at the scales of individuals and communities, which is one of the main reasons why flood coping actions are taken. It is shown through examples that frequent flood events may result in moderate damages because they ensure that the

Natural and traditional defense mechanisms to reduce climate risks in coastal zones of Bangladesh

OpenAIRE

Mohammed Ataur Rahman; Sowmen Rahman

2015-01-01

Substantially resourceful and densely populated coastal zones of Bangladesh experience numerous extreme events linked to hydro-meteorological processes viz. cyclones, tidal surges, floods, salinity intrusion and erosion etc. These hazards give rise to extensive damage to property and loss of lives every year. Further, anthropogenic activities in the coastal zones are accentuating environmental degradation causing widespread suffering. Cyclones and tornadoes in particular damage infrastructure...

Floods

Science.gov (United States)

Floods are common in the United States. Weather such as heavy rain, thunderstorms, hurricanes, or tsunamis can ... is breached, or when a dam breaks. Flash floods, which can develop quickly, often have a dangerous ...

Moisture Sources and Large-Scale Dynamics Associated with a Flash Flood Event in Portugal

Science.gov (United States)

Liberato, Margarida L. R.; Ramos, Alexandre M.; Trigo, Ricardo M.; Trigo, Isabel F.; María Durán-Quesada, Ana; Nieto, Raquel; Gimeno, Luis

2013-04-01

On 18-19 November 1983, the region of Lisbon, in Portugal, was affected by a heavy precipitation event, soon followed by flash flooding, urban inundations and a burst of landslides around Lisbon [Zêzere et al., 2005] causing considerable infrastructure damage and human fatalities. With a total of 95.6 mm in 24 h observed at the longest serving station in Portugal (Lisbon's Dom Luiz Observatory), this was the rainiest day during the twentieth century and one of the rainiest registered since 1864. We found that this event was triggered by the transport of tropical and subtropical moisture associated with an extratropical cyclone. The low favored a large stream of (sub) tropical air that extended over more than 10° of latitude and across the North Atlantic Ocean, carrying a large amount of moisture originally from lower latitudes, a so-called atmospheric river. The stationary position of the jet stream along the East Atlantic Ocean through Iberia caused a strong enhancement of the precipitation associated with the moist air. A Lagrangian analysis of the transport of moisture in the Euro-Atlantic sector was performed based on the methodology developed by Stohl and James [2004, 2005], using the FLEXPART model. This Lagrangian methodology was employed to show that the evaporative sources for the precipitation falling over the area of Lisbon were distributed over large sectors of the tropical-subtropical North Atlantic Ocean and included a significant contribution from the (sub) tropics. This study [Liberato et al., 2012] aims to provide an example of the application of distinct Lagrangian techniques to achieve a better understanding of the relation between extratropical cyclones and the occurrence of a heavy precipitation event on the Iberian Peninsula. Acknowledgments: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) Programme and by national funds

Improving operational flood forecasting through data assimilation

Science.gov (United States)

Rakovec, Oldrich; Weerts, Albrecht; Uijlenhoet, Remko; Hazenberg, Pieter; Torfs, Paul

2010-05-01

Accurate flood forecasts have been a challenging topic in hydrology for decades. Uncertainty in hydrological forecasts is due to errors in initial state (e.g. forcing errors in historical mode), errors in model structure and parameters and last but not least the errors in model forcings (weather forecasts) during the forecast mode. More accurate flood forecasts can be obtained through data assimilation by merging observations with model simulations. This enables to identify the sources of uncertainties in the flood forecasting system. Our aim is to assess the different sources of error that affect the initial state and to investigate how they propagate through hydrological models with different levels of spatial variation, starting from lumped models. The knowledge thus obtained can then be used in a data assimilation scheme to improve the flood forecasts. This study presents the first results of this framework and focuses on quantifying precipitation errors and its effect on discharge simulations within the Ourthe catchment (1600 km2), which is situated in the Belgian Ardennes and is one of the larger subbasins of the Meuse River. Inside the catchment, hourly rain gauge information from 10 different locations is available over a period of 15 years. Based on these time series, the bootstrap method has been applied to generate precipitation ensembles. These were then used to simulate the catchment's discharges at the outlet. The corresponding streamflow ensembles were further assimilated with observed river discharges to update the model states of lumped hydrological models (R-PDM, HBV) through Residual Resampling. This particle filtering technique is a sequential data assimilation method and takes no prior assumption of the probability density function for the model states, which in contrast to the Ensemble Kalman filter does not have to be Gaussian. Our further research will be aimed at quantifying and reducing the sources of uncertainty that affect the initial

Cascadia Subduction Zone Earthquake Source Spectra from an Array of Arrays

Science.gov (United States)

Gomberg, J. S.; Vidale, J. E.

2011-12-01

suggests it is more likely that variation in attenuation modulates the spectra. Because the variations in apparent source spectra correlate well with source location, but poorly with receiver location, we infer that near-source attenuation differences likely are much more significant. We conclude that the conventional wisdom may require some revision - that near-source propagation effects may be responsible for some fraction of what has hitherto been attributed to source processes. Moreover, our results further suggest that subduction zone earthquakes do not separate neatly into 'slow' and 'fast' classes, but likely span a continuum.

Scale orientated analysis of river width changes due to extreme flood hazards

Directory of Open Access Journals (Sweden)

G. Krapesch

2011-08-01

Full Text Available This paper analyses the morphological effects of extreme floods (recurrence interval >100 years and examines which parameters best describe the width changes due to erosion based on 5 affected alpine gravel bed rivers in Austria. The research was based on vertical aerial photos of the rivers before and after extreme floods, hydrodynamic numerical models and cross sectional measurements supported by LiDAR data of the rivers. Average width ratios (width after/before the flood were calculated and correlated with different hydraulic parameters (specific stream power, shear stress, flow area, specific discharge. Depending on the geomorphological boundary conditions of the different rivers, a mean width ratio between 1.12 (Lech River and 3.45 (Trisanna River was determined on the reach scale. The specific stream power (SSP best predicted the mean width ratios of the rivers especially on the reach scale and sub reach scale. On the local scale more parameters have to be considered to define the "minimum morphological spatial demand of rivers", which is a crucial parameter for addressing and managing flood hazards and should be used in hazard zone plans and spatial planning.

'Are you prepared?' Representations and management of floods in Lomanikoro, Rewa (Fiji).

Science.gov (United States)

Nolet, Emilie

2016-10-01

The islands of Fiji, in the Western Pacific, are exposed to a wide range of natural hazards. Tropical storms and associated floods are recurring natural phenomena, but it has been regularly alleged that Fijians lack preparation, over-rely on state assistance in post-disaster situations or engage in risky behaviours that aggravate the negative impact of floods. Risk reduction strategies, which are now implemented by government authorities and international organisations, heavily promote the principle of 'community preparedness'. Both community awareness programmes and capacity-building programmes are conducted throughout the country in the most vulnerable communities. This paper analyses how the inhabitants of Lomanikoro village, in the low areas of the Rewa Delta, perceive and manage existing flood risks. It examines social and cultural factors that contribute to shape risk response locally-in particular, why villagers may be reluctant to adopt some recommended preparedness measures and resettle in higher, safer zones. © 2016 The Author(s). Disasters © Overseas Development Institute, 2016.

76 FR 40670 - Proposed Flood Elevation Determinations

Science.gov (United States)

2011-07-11

...) Depth in feet above State City/town/county Source of flooding Location ** ground [caret] Elevation in... Contentnea Creek +76 +77 Town of Black Creek, confluence. Unincorporated Areas of Wilson County... +63 Town of Stantonsburg, confluence. Unincorporated Areas of Wilson County. Approximately 0.8 mile...

76 FR 8978 - Proposed Flood Elevation Determinations

Science.gov (United States)

2011-02-16

.../town/county Source of flooding Location ** ground [caret] Elevation in meters (MSL) Existing Modified Unincorporated Areas of Yolo County, California California Unincorporated Areas of Cache Creek Settling Basin At........ Entire None +901 Town of shoreline Wolcottvill e, Unincorpora ted Areas of LaGrange County. * National...

76 FR 36482 - Proposed Flood Elevation Determinations

Science.gov (United States)

2011-06-22

.../town/county Source of flooding Location ** ground [caret] Elevation in meters (MSL) Existing Modified City of Colonial Heights, Virginia Virginia City of Colonial Heights Old Town Creek Approximately 0.63... for inspection at 202 James Avenue, Colonial Heights, VA 23834. Unincorporated Areas of Halifax County...

Probabilistic flood extent estimates from social media flood observations

NARCIS (Netherlands)

Brouwer, Tom; Eilander, Dirk; Van Loenen, Arnejan; Booij, Martijn J.; Wijnberg, Kathelijne M.; Verkade, Jan S.; Wagemaker, Jurjen

2017-01-01

The increasing number and severity of floods, driven by phenomena such as urbanization, deforestation, subsidence and climate change, create a growing need for accurate and timely flood maps. In this paper we present and evaluate a method to create deterministic and probabilistic flood maps from

Probabilistic flood extent estimates from social media flood observations

NARCIS (Netherlands)

Brouwer, Tom; Eilander, Dirk; Van Loenen, Arnejan; Booij, Martijn J.; Wijnberg, Kathelijne M.; Verkade, Jan S.; Wagemaker, Jurjen

2017-01-01

The increasing number and severity of floods, driven by phenomena such as urbanization, deforestation, subsidence and climate change, creates a growing need for accurate and timely flood maps. This research focussed on creating flood maps using user generated content from Twitter. Twitter data has

Improving Global Flood Forecasting using Satellite Detected Flood Extent

NARCIS (Netherlands)

Revilla Romero, B.

2016-01-01

Flooding is a natural global phenomenon but in many cases is exacerbated by human activity. Although flooding generally affects humans in a negative way, bringing death, suffering, and economic impacts, it also has potentially beneficial effects. Early flood warning and forecasting systems, as well

Radiation danger of exclusion zone objects

International Nuclear Information System (INIS)

Kholosha, V.I.; Proskura, N.I.; Ivanov, Yu.A.; Kazakov, S.V.; Arkhipov, A.N.

2001-01-01

The analysis of radiation danger of the Exclusion Zone objects was made. Here, the Zone is defined as the territory from which the population has been evacuated in 1986 owing to the Chernobyl accident and possible outflow of the contaminated substances out of the borders is potentially dangerous to the Ukraine. In the present work were analyzed such problems as sources of radiation danger in the Zone, ways of radionuclide migration out of the borders of the Zone in normal and emergency situations, the non-radiation (ecological) danger factors of the Zone objects, doses (individual and collective) from various sources and on separate ways of their formation, and the characteristics of radiation danger of the Zone objects. The conclusions are: (1) Radionuclide flows both from technologic and natural sources exceed those from Shelter objects, (2) Under emergency conditions, radionuclide flows and doze loading remain comparable with those from emergency sources, (3) To solve some management tasks in radiation situation, the basic works on the Shelter objects should be oriented to decrease probability of emergency occurrence and to reduce radiation influence (prevention wash-outs during high waters, fire-prevention measures in forests and strengthening of the control behind non-authorized use of objects in the Zone). (S. Ohno)

[Transfer characteristic and source identification of soil heavy metals from water-level-fluctuating zone along Xiangxi River, three-Gorges Reservoir area].

Science.gov (United States)

Xu, Tao; Wang, Fei; Guo, Qiang; Nie, Xiao-Qian; Huang, Ying-Ping; Chen, Jun

2014-04-01

Transfer characteristics of heavy metals and their evaluation of potential risk were studied based on determining concentration of heavy metal in soils from water-level-fluctuating zone (altitude:145-175 m) and bank (altitude: 175-185 m) along Xiangxi River, Three Gorges Reservoir area. Factor analysis-multiple linear regression (FA-MLR) was employed for heavy metal source identification and source apportionment. Results demonstrate that, during exposing season, the concentration of soil heavy metals in water-level-fluctuation zone and bank showed the variation, and the concentration of soil heavy metals reduced in shallow soil, but increased in deep soil at water-level-fluctuation zone. However, the concentration of soil heavy metals reduced in both shallow and deep soil at bank during the same period. According to the geoaccumulation index,the pollution extent of heavy metals followed the order: Cd > Pb > Cu > Cr, Cd is the primary pollutant. FA and FA-MLR reveal that in soils from water-level-fluctuation zone, 75.60% of Pb originates from traffic, 62.03% of Cd is from agriculture, 64.71% of Cu and 75.36% of Cr are from natural rock. In soils from bank, 82.26% of Pb originates from traffic, 68.63% of Cd is from agriculture, 65.72% of Cu and 69.33% of Cr are from natural rock. In conclusion, FA-MLR can successfully identify source of heavy metal and compute source apportionment of heavy metals, meanwhile the transfer characteristic is revealed. All these information can be a reference for heavy metal pollution control.

Lasting Effects of Glacial Lake Outburst Floods on Subglacial Drainage Networks

Science.gov (United States)

Robbins, M.; Hendy, I. L.; Bassis, J. N.; Aciego, S.; Stevenson, E. I.

2017-12-01

Supraglacial lakes forming in the ablation zone around the Greenland Ice Sheet will likely migrate toward higher elevations as polar temperatures rise through the 21st century. Present understanding of lake drainage shows it can temporarily enhance ice sheet motion, but other possible effects and interactions - especially with older pre-existing subglacial reservoirs - remain unexamined. Here we investigate possible enduring effects of the record high 2012 melt year on the en/subglacial hydrologic network, how this network responds to immediate high fluxes of water from floods, and how these phenomena might connect to previously isolated subglacial pools. Lake Hullet is a large ice dammed lake situated in south Greenland 22km up-ice from where Kiattuut Sermiat (KS) branches from a larger outlet glacier. Lake Hullet rests on bedrock and is contained by a bedrock ridge. It drains roughly annually through Lake Hullet's hydrologic network in a glacial lake outburst flood (GLOF) when water level rises such that it can flow over the obstructive ridge. Subglacial water samples collected from the toe of KS in July 2013 pre-flood were dated using U isotopes with 222Rn concentrations as well as noble gas ratios. These two independent methods reveal an exceedingly old water age of > 1000 years, indicating existence of isolated enduring subglacial meltwater pool(s). A comparison field study at the KS toe in August and September 2015 re-examined glacial hydrochemistry in a time series. 2015 222Rn concentrations are lower than 2013 values, suggesting less water-rock interaction, a reduction in residence time, and a proximal meltwater source. Increased water volume from the record high 2012 melt year may have enlarged the existing en/subglacial drainage network further into the ice sheet releasing meltwater with longer residence times beneath the ice, with effects lasting into subsequent melt seasons due to the stability of channels maintained from recurrent floods. These

Surrogate modeling of joint flood risk across coastal watersheds

Science.gov (United States)

Bass, Benjamin; Bedient, Philip

2018-03-01

This study discusses the development and performance of a rapid prediction system capable of representing the joint rainfall-runoff and storm surge flood response of tropical cyclones (TCs) for probabilistic risk analysis. Due to the computational demand required for accurately representing storm surge with the high-fidelity ADvanced CIRCulation (ADCIRC) hydrodynamic model and its coupling with additional numerical models to represent rainfall-runoff, a surrogate or statistical model was trained to represent the relationship between hurricane wind- and pressure-field characteristics and their peak joint flood response typically determined from physics based numerical models. This builds upon past studies that have only evaluated surrogate models for predicting peak surge, and provides the first system capable of probabilistically representing joint flood levels from TCs. The utility of this joint flood prediction system is then demonstrated by improving upon probabilistic TC flood risk products, which currently account for storm surge but do not take into account TC associated rainfall-runoff. Results demonstrate the source apportionment of rainfall-runoff versus storm surge and highlight that slight increases in flood risk levels may occur due to the interaction between rainfall-runoff and storm surge as compared to the Federal Emergency Management Association's (FEMAs) current practices.

Using an extended 2D hydrodynamic model for evaluating damage risk caused by extreme rain events: Flash-Flood-Risk-Map (FFRM) Upper Austria

Science.gov (United States)

Humer, Günter; Reithofer, Andreas

2016-04-01

at 20th of June 2012, based on open data sources of geology, soil and land use. The aim of FFRM is to provide an estimation of the damage risk caused by flash-floods for the whole of Upper Austria. To address the hazard, inundation depths were calculated with the extended 2D-model using design rains with an 100-year return period provided by the Environmental Ministry [7]. The potential damage was calculated using damage functions, which were derived from our experience from damage surveys of past events in Austria and according to guidelines for determination of cost-benefit-ratios for flood protection measures [8]. The greatest difficulty was to get appropriate data for the distribution of houses and industrial plants. Zoning plans provide good information on spatial distribution of residential, commercial and industrial areas, but does not contain information on the kind of industry, which is essential for estimating absolute damage values. To get a first idea detailed information from surveyed areas was intersected with the zoning plan, which provides an average damage in the respective zones. The first results can be found on www.waterviewer.com and will be updated with the further development of the project. [1] URBAS, risk management of extreme flooding events - prediction and management of flash floods in urban areas, www.urbanesturzfluten.de, prompted on 13th of November 2014 [2] Società Meteorologica Italiana (SMI), http://www.nimbus.it/eventi/2013/130624flashfloodRimini.pdf, prompted on 13th of November 2014 [3]Newspaper "Österreich", http://www.oe24.at/oesterreich/chronik/Sturzflut-Regen-legt-Ost-Oesterreich-lahm/1509113, prompted on 13th of November 2014 [4] Newspaper "Oberösterreichische Nachrichten", http://www.nachrichten.at/oberoesterreich/Unwetter-Mure-riss-Strasse-mit-Wohnhaus-in-Gosau-gefaehrdet;art4,911288 , prompted on 13th of November 2014 [5] Sharing Water-related Information to Tackle Changes in the Hydrosphere - for Operational Needs

Flood Label for buildings : a tool for more flood-resilient cities

NARCIS (Netherlands)

Hartmann, T.; Scheibel, Marc

2016-01-01

River floods are among the most expensive natural disasters in Europe. Traditional flood protection methods are not sufficient anymore. It is widely acknowledged in the scholarly debate and in practice of flood risk management that traditional flood protection measures such as dikes need to be

Radiation protection zoning

International Nuclear Information System (INIS)

2015-01-01

Radiation being not visible, the zoning of an area containing radioactive sources is important in terms of safety. Concerning radiation protection, 2 work zones are defined by regulations: the monitored zone and the controlled zone. The ministerial order of 15 may 2006 settles the frontier between the 2 zones in terms of radiation dose rates, the rules for access and the safety standards in both zones. Radioprotection rules and the name of the person responsible for radiation protection must be displayed. The frontier between the 2 zones must be materialized and marked with adequate equipment (specific danger signs and tapes). Both zones are submitted to selective entrance, the access for the controlled zone is limited because of the radiation risk and of the necessity of confining radioactive contamination while the limitation of the access to the monitored zone is due to radiation risk only. (A.C.)

Seepage investigation by using Isotope and Geophysical Techniques in Gumti Flood Embankment/Dyke, Comilla

International Nuclear Information System (INIS)

Ahmed, N.; Wallin, B. G.; Majumder, R. K.; Mikail, M.; Rahman, M. S.

2004-06-01

Gumti Flood Control Embankment/Dyke is vital for irrigation water supply and flood control. Water seepage/leakage and slope failures are the major issues in Gumti earthen dyke. The distinct seepage and slope failure zone were observed at three places (Farizpur, Kathalia and Ebdarpur) along the countryside of left dyke. The isotopic technique has been integrated in the conventional hydrologic investigations. The isotope methodology works essentially by developing a characteristics pattern of the isotopic composition to identify the sources and flow dynamics of seeping/leaking in the dykes. Two sampling campaigns were conducted; one was on October, 2002 and the other was on July, 2003; near the seepage/leakage site for chemical analysis and stable isotopic analysis (''2H and ''1 8 O). Both samplings were done after recession of peak water level in the Gumti river. Interpretation of the hydrochemical data implies that the groundwater near the investigated seepage zones is Na-Ca-HCO 3 type and the river water is Ca-Mg-HCO 3 type. The chlorides content of both groundwater and river water are found mostly similar, indicating mixing between the two water system. The stable isotopes (''2H and ''1 8 O) of groundwater fall on the Meteoric Water Line, ranging the oxygen-18 values from -4.98 to -5.46 per mil and deuterium values from -30.0 to -33.6 per mil. It indicates the recharge from the river water during peak water level in the river Gumti. On the other hand, the stable isotopes of the Gumti river show some evaporation effect, which might have occurred due to stagnation of flowing water in the river. The oxygen-18 and deuterium values for river water range from -3.61 to -4.43 per mil and from -22.30 to -28.48 per mil respectively. These isotope results reflect the hydraulic connectivity between the river water and groundwater through the base of dyke. The earth imaging resistivity survey was carried out in the dry period along the four above mentioned areas of the Gumti

Flooding in imagination vs flooding in vivo: A comparison with agoraphobics

NARCIS (Netherlands)

Emmelkamp, Paul M.G.; Wessels, Hemmy

In this investigation of agoraphobic patients, 3 different flooding procedures were compared: (1) prolonged exposure in vivo, (2) flooding in the imagination by a ‘live’ therapist and (3) a combination of flooding in the imagination and flooding in vivo. After an intermediate-test all clients were

Integrating heterogeneous earth observation data for assessment of high-resolution inundation boundaries generated during flood emergencies.

Science.gov (United States)

Sava, E.; Cervone, G.; Kalyanapu, A. J.; Sampson, K. M.

2017-12-01

The increasing trend in flooding events, paired with rapid urbanization and an aging infrastructure is projected to enhance the risk of catastrophic losses and increase the frequency of both flash and large area floods. During such events, it is critical for decision makers and emergency responders to have access to timely actionable knowledge regarding preparedness, emergency response, and recovery before, during and after a disaster. Large volumes of data sets derived from sophisticated sensors, mobile phones, and social media feeds are increasingly being used to improve citizen services and provide clues to the best way to respond to emergencies through the use of visualization and GIS mapping. Such data, coupled with recent advancements in data fusion techniques of remote sensing with near real time heterogeneous datasets have allowed decision makers to more efficiently extract precise and relevant knowledge and better understand how damage caused by disasters have real time effects on urban population. This research assesses the feasibility of integrating multiple sources of contributed data into hydrodynamic models for flood inundation simulation and estimating damage assessment. It integrates multiple sources of high-resolution physiographic data such as satellite remote sensing imagery coupled with non-authoritative data such as Civil Air Patrol (CAP) and `during-event' social media observations of flood inundation in order to improve the identification of flood mapping. The goal is to augment remote sensing imagery with new open-source datasets to generate flood extend maps at higher temporal and spatial resolution. The proposed methodology is applied on two test cases, relative to the 2013 Boulder Colorado flood and the 2015 floods in Texas.

Field-flood requirements for emission computed tomography with an Anger camer

International Nuclear Information System (INIS)

Rogers, W.L.; Clinthorne, N.H.; Harkness, B.A.; Koral, K.F.; Keyes, J.W. Jr.

1982-01-01

Emission computed tomography with a rotating camera places stringent requirements on camera uniformity and the stability of camera response. In terms of clinical tomographic imaging, we have studied the statistical accuracy required for camera flood correction, the requirements for flood accuracy, the utility and validity of flood and data image smoothing to reduce random noise effects, and the magnitude and effect of camera variations as a function of angular position, energy window, and tuning. Uniformity of the corrected flood response must be held to better than 1% to eliminate image artifacts that are apparent in a million-count image of a liver slice. This requires calibration with an accurate, well-mixed flood source. Both random fluctuations and variations in camera response with rotation must be kept below 1%. To meet the statistical limit, one requires at least 30 million counts for the flod-correction image. Smoothing the flood image alone introduces unacceptable image artifacts. Smoothing both the flood image and data, however, appears to be a good approach toward reducing noise effects. Careful camera tuning and magnetic shield design provide camera stability suitable for present clinical applications

FLOOD 3 code conversion from Apollo to HP

Energy Technology Data Exchange (ETDEWEB)

Lee, Hae Cho [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-01-01

FLOOD3 is a Fortran program used to analyze LOCA Reflood and Post Reflood transients for purpose of mechanistically generating containment sizing mass/energy source terms. The reflood time frame starts when safety injection water first enters the bottom of the core, following the initial LOCA blowdown phase, and the ends when liquid level in the core is high enough to quench the core. The post reflood phase starts at the end of reflood phase and lasts until the end of LOCA transient period. Longterm core cooling is initiated following post reflood phase. FLOOD3 code dose not contain separate capability for longterm cooling analysis. This report firstly describes detailed work carried out for installation of FLOOD3 on Apollo DN10000 and code validation results after installation. Secondly, A series of work is also describes in relation to installation of FLOOD3 on HP 9000/700 series as well as relevant code validation results. Attached is a report on software verification and validation results. 7 refs. (Author) .new.

FLOOD 3 code conversion from Apollo to HP

International Nuclear Information System (INIS)

Lee, Hae Cho

1996-01-01

FLOOD3 is a Fortran program used to analyze LOCA Reflood and Post Reflood transients for purpose of mechanistically generating containment sizing mass/energy source terms. The reflood time frame starts when safety injection water first enters the bottom of the core, following the initial LOCA blowdown phase, and the ends when liquid level in the core is high enough to quench the core. The post reflood phase starts at the end of reflood phase and lasts until the end of LOCA transient period. Longterm core cooling is initiated following post reflood phase. FLOOD3 code dose not contain separate capability for longterm cooling analysis. This report firstly describes detailed work carried out for installation of FLOOD3 on Apollo DN10000 and code validation results after installation. Secondly, A series of work is also describes in relation to installation of FLOOD3 on HP 9000/700 series as well as relevant code validation results. Attached is a report on software verification and validation results. 7 refs. (Author) .new

76 FR 1535 - Final Flood Elevation Determinations

Science.gov (United States)

2011-01-11

... in feet (NGVD) + Elevation in feet (NAVD) State City/town/county Source of flooding Location Depth in feet above ground [caret] Elevation in meters (MSL) Modified Unincorporated Areas of Poinsett County... with the St. Francis River...... +212 Areas of Poinsett County. Approximately 0.45 mile downstream of...

75 FR 68710 - Final Flood Elevation Determinations

Science.gov (United States)

2010-11-09

...: * Elevation in feet (NGVD) + Elevation in feet (NAVD) State City/town/county Source of flooding Location Depth... County, California Docket Nos.: FEMA-B-7762, FEMA-B-7795, and FEMA-B-1053 California Unincorporated Oregon Slough..... City of Montague +2503 Areas of Siskiyou and County. Unincorporated Siskiyou County...

76 FR 66887 - Proposed Flood Elevation Determinations

Science.gov (United States)

2011-10-28

...) Depth in feet above State City/town/county Source of flooding Location** ground [caret] Elevation in meters (MSL) Existing Modified Town of Richmond, Vermont Vermont Town of Richmond........ Winooski River... Incorporated Areas Little Thompson River At the downstream side None +4935 Town of Berthoud, of Weld County...

77 FR 49379 - Final Flood Elevation Determinations

Science.gov (United States)

2012-08-16

... in feet (NGVD) + Elevation in feet (NAVD) State City/town/county Source of flooding Location Depth in feet above ground [caret] Elevation in meters (MSL) Modified Unincorporated Areas of Washington County... of the +35 Areas of railroad. Washington County. Approximately 2.1 miles upstream of the railroad...

75 FR 43418 - Final Flood Elevation Determinations

Science.gov (United States)

2010-07-26

... follows: * Elevation in feet (NGVD) + Elevation in feet (NAVD) State City/town/county Source of flooding... +869 Town of Peoria, upstream of Main Street. Unincorporated Areas of Ottawa County. Approximately 1.... Town of Peoria Maps are available for inspection at the Ottawa County Courthouse, 102 East Central...

78 FR 78808 - Proposed Flood Elevation Determinations for Pierce County, Washington, and Incorporated Areas