Barrier-based Longitudinal Connectivity Index for Managing Urban Rivers

A large variety of barriers can affect longitudinal connectivity, which leads to shipping blocking and even flood hazard. However, few existing methods can quantify physically the river channel connectivity from the barrier’s details perspective in a watershed. This paper establishes a new model of the River Channel Connectivity Index (RCCI) to quantify the unobstructed degree of river flow in river channels within geographic information system (GIS ) platforms based on the modified concept of time accessibility. A comprehensive classification system of barriers is setup before these barriers are identified by the remote sensing technology. The model is applied to Dashi Watershed in suburban Beijing, China. Results show that submersible bridges and sediment siltation are the main barriers in the watershed. RCCI values in the mountainous areas are generally higher than that of the plains. The assessment results verified by two historical flood events show that the RCCI can reveal where the river channel connectivity is impaired, how serious it is, and what the reason is for managers. Through scenarios’ results, the best restoration measure for each tributary is obtained from the perspective of reducing flood hazards. The new RCCI method not only has methodological significance, but also helps policymakers to enhance river flooding reduction and determine restoration priorities of the river channel.

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Compounding effects of sea level rise and fluvial flooding

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1620325114 ◽

2017 ◽

Vol 114 (37) ◽

pp. 9785-9790 ◽

Cited By ~ 104

Author(s):

Hamed R. Moftakhari ◽

Gianfausto Salvadori ◽

Amir AghaKouchak ◽

Brett F. Sanders ◽

Richard A. Matthew

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Hazard Assessment ◽

Failure Probability ◽

River Flow ◽

Flood Hazard ◽

High Tide ◽

Probability Method ◽

Flood Hazards ◽

Flood Hazard Assessment

Sea level rise (SLR), a well-documented and urgent aspect of anthropogenic global warming, threatens population and assets located in low-lying coastal regions all around the world. Common flood hazard assessment practices typically account for one driver at a time (e.g., either fluvial flooding only or ocean flooding only), whereas coastal cities vulnerable to SLR are at risk for flooding from multiple drivers (e.g., extreme coastal high tide, storm surge, and river flow). Here, we propose a bivariate flood hazard assessment approach that accounts for compound flooding from river flow and coastal water level, and we show that a univariate approach may not appropriately characterize the flood hazard if there are compounding effects. Using copulas and bivariate dependence analysis, we also quantify the increases in failure probabilities for 2030 and 2050 caused by SLR under representative concentration pathways 4.5 and 8.5. Additionally, the increase in failure probability is shown to be strongly affected by compounding effects. The proposed failure probability method offers an innovative tool for assessing compounding flood hazards in a warming climate.

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Flood hazard in Hungary: a re-assessment

Open Geosciences ◽

10.2478/v10085-010-0029-0 ◽

2010 ◽

Vol 2 (4) ◽

Cited By ~ 3

Author(s):

Dénes Lóczy

Keyword(s):

River Flow ◽

Flash Flood ◽

Flood Hazard ◽

Flood Hazards ◽

Rainfall Events ◽

Groundwater Levels ◽

Excess Water ◽

Water Hazard ◽

Map Series ◽

The 19Th Century

AbstractSome decades ago the concept of flood hazard in the Carpathian Basin was interpreted solely as riverine flood hazard, mostly restricted to the Tisza and Danube Rivers, and was closely associated with the impacts of river flow regulation in the second half of the 19th century. Recent assessments, however, allow us to outline a more diverse picture. Climate change is predicted to bring about both an increase in the frequency of droughts and excessive rainfall events, resulting in irregulaties in the water regimes of rivers in Hungary. Excess water hazard from raised groundwater levels is found to affect much larger areas than previously thought. Recent strongly localized cloudbursts, point to the increasing significance of flash floods.Riverine flooding and excess water hazard are more common in lowlands, whereas flash flood hazards are primarily, but not exclusively, affect the mountainous and hilly regions of the country. This paper intends to assess the relative importance of the three types of inundation hazard analyzed and to illustrate their overall spatial occurrences by microregions on a map series.

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Model cascade from meteorological drivers to river flood hazard: flood-cascade v1.0

10.5194/gmd-2020-280 ◽

2020 ◽

Author(s):

Peter Uhe ◽

Daniel Mitchell ◽

Paul D. Bates ◽

Nans Addor ◽

Jeff Neal ◽

...

Keyword(s):

Climate Change ◽

Climate Models ◽

River Flow ◽

Flood Hazard ◽

Data Sets ◽

Flood Inundation ◽

River Flooding ◽

Global Data Sets ◽

Global Data

Abstract. There is an urgent need for the climate community to translate their meteorological drivers into relevant hazard estimates. This is especially important for the climate attribution and climate projection communities as we seek to understand how anthropogenic climate change has, and will, impact our society. This can be particularly challenging because there are often multiple specialized steps to model the hazard. Current climate change assessments of flood risk typically neglect key processes, and instead of explicitly modeling flood inundation, they commonly use precipitation or river flow as proxies for flood hazard. Here, we lay out a clear methodology for taking meteorological drivers, e.g., from observations or climate models, through to high-resolution (~ 90 m) river flooding (fluvial) hazards. The meteorological inputs (precipitation and air temperature) are transformed through a series of modeling steps to yield, in turn, surface runoff, river flow, and flood inundation. We explore uncertainties at different modeling steps. The flood inundation estimates can then be directly related to impacts felt at community and household levels to determine exposure and risks from flood events. The approach uses global data-sets and thus can be applied anywhere in the world, but we use the Brahmaputra river in Bangladesh as a case study in order to demonstrate the necessary steps in our hazard framework.

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A new dataset of river flood hazard maps for Europe and the Mediterranean Basin region

10.5194/essd-2020-313 ◽

2021 ◽

Author(s):

Francesco Dottori ◽

Lorenzo Alfieri ◽

Alessandra Bianchi ◽

Jon Skoien ◽

Peter Salamon

Keyword(s):

River Flow ◽

Flood Hazard ◽

Correct Identification ◽

Return Periods ◽

Hazard Maps ◽

River Channels ◽

Large Variability ◽

Continental Scale ◽

The Mediterranean ◽

Flood Hazard Maps

Abstract. Continental scale hazard maps for riverine floods have grown in importance in the last years. Nowadays, they are used for a variety of research and commercial activities, such as evaluating present and future risk scenarios and adaptation strategies, as well as a support of national and local flood risk management plans. Here, we present a new set of hazard maps for river flooding that covers most of the geographical Europe and all the river basins entering the Mediterranean and Black Seas in the Caucasus, Middle East and Northern Africa countries. Maps represent inundation along 329’000 km of river network at 100 m resolution, for six different flood return periods. The input river flow data is produced by the hydrological model LISFLOOD, while inundation simulations are performed with the 2D hydrodynamic modelling LISFLOOD-FP. To provide an overview of the skill of the new maps, we undertake a detailed validation exercise of the new maps using official hazard maps for Hungary, Italy, Norway, Spain and the United Kingdom. We find that modelled maps can identify on average two-thirds of reference flood extent, however they also overestimate flood-prone areas for flood probabilities below 1-in-100-year, while for return periods equal or above 500 years the maps can correctly identify more than half of flooded areas. We attribute the observed skill to a number of shortcomings of the modelling framework, such as the absence of flood protections and rivers with upstream area below 500 km2, and the limitations in representing river channels and topography of low land areas. In addition, the large variability of reference maps affects the correct identification of the areas for the validation, thus penalizing scores. However, modelled maps achieve comparable results to existing large-scale flood models when using similar parameters for the validation. We conclude that recently released high-resolution elevation datasets combined with reliable data of river channel geometry may greatly contribute to improve future versions of continental-scale flood hazard maps. The database is available for download at https://data.jrc.ec.europa.eu/dataset/1d128b6c-a4ee-4858-9e34-6210707f3c81 (Dottori et al., 2020a).

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Effects of Bridge Piers on Flood Hazards: A Case Study on the Jialing River in China

Water ◽

10.3390/w11061181 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1181

Author(s):

Wen Wang ◽

Kaibo Zhou ◽

Haixiao Jing ◽

Juanli Zuo ◽

Peng Li ◽

...

Keyword(s):

Numerical Model ◽

Eddy Currents ◽

Flood Hazard ◽

Maximum Velocity ◽

Bridge Piers ◽

Sensitivity Analyses ◽

Flood Hazards ◽

River Channels ◽

Cross Sectional ◽

Jialing River

Bridge piers on river channels can cause obstacles for flood flow by reducing the cross-sectional area and inducing local eddy currents and high flow velocities, which may destroy hydraulic structures. A two-dimensional numerical model was used to investigate the effects of bridge piers on river flood hazards in the Jialing River, China. For the modeling, Mike 21 FM was used, which is an unstructured mesh and finite volume model that solves the shallow water equations. The numerical model was validated with collected historical flood traces, and sensitivity analyses identified the effects of the Manning coefficient and the dependence on the grid size. The influence of backwater effects on the flow field was analyzed by comparing numerical results with and without piers. The results showed that the most significant impacts were caused by the Fengxian Bridge. The maximum water level rise was about 1 m and the maximum velocity near this bridge decreased by 22.77% for a 10-year flood. We found that the top elevations of planned levees near the bridges must be increased by 0.15–0.36 m. The influence of bridge piers on the flood velocity field is more complex. These findings will help flood hazard management in this river and provides a reference for similar projects.

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Flood hazards in the headwaters area: lessons learned from a survey of households in the upper Myjava basin, Slovakia

Water Policy ◽

10.2166/wp.2017.008 ◽

2017 ◽

Vol 19 (6) ◽

pp. 1081-1096 ◽

Cited By ~ 2

Author(s):

Ľ. Solín ◽

M. Sládeková Madajová ◽

L. Michaleje

Keyword(s):

Risk Management ◽

Flood Risk ◽

Flood Hazard ◽

Flood Risk Management ◽

Present Knowledge ◽

Lessons Learned ◽

Flood Hazards ◽

River Flooding ◽

Local Factors ◽

Flood Defence

Abstract The aims of this paper are to present knowledge about the threat of flooding in the upper basins of the Myjava River, obtained using a questionnaire, and to identify the potential lessons for flood risk management. The questionnaire was designed to obtain information about households' experience with flooding, including the type of floods experienced, the locations of flooding, the exacerbating factors contributing to flood risk that they considered to be important and their proposals to minimise the occurrence of flooding. Findings obtained using the questionnaire suggest that: (i) in the upper basins, sheetwash flooding is as important as river flooding and the assessment of flood hazards should include all significant types of flood hazard; (ii) flood risk management in the upper basins should primarily focus on the systematic maintenance of small watercourses and on eliminating local factors that increase the risk of all types of flooding. The building of structures for flood defence should be seen as a last resort when other options are not effective.

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Numerical Simulation of Crude Oil Spreading in a Complex River Channel

Volume 3: Operations, Monitoring, and Maintenance; Materials and Joining ◽

10.1115/ipc2020-9565 ◽

2020 ◽

Author(s):

Dongliang Yu ◽

Ji Wang ◽

Quan Cao ◽

Xinglong Zhang ◽

Xueguang Liu

Keyword(s):

Crude Oil ◽

River Flow ◽

Simulated Data ◽

River Channel ◽

Flowing Water ◽

River Channels ◽

Spreading Process ◽

Fluid Mixture ◽

Oil Transportation ◽

Pass Through

Abstract Crude oil leaking in rivers may cause serious damages, such as environmental pollution and death of river animals. The crude oil spreading in rivers could be much faster than that on lands, as the leaking crude oil may flow rapidly downstream with the flowing water. Therefore, accurately estimating the transient crude oil spreading area in rivers is a vital task for emergency response and disaster rescue. However, the estimating methods in the literature mainly refer to spreading process in underwater, ocean and soil, which commonly happened in the history. The crude oil transportation pipelines in China pass through many rivers with very complex channel geometries, introducing the necessity of estimating of leaking crude oil spreading in actual river channels. In the current study, the crude oil spreading process along an actual river channel is numerically simulated. The river channel geometry is extracted from a map database, which is further treated using image binarization and edge extraction to obtain the discrete river channel data. The river channel data is then smoothed by picking less data representing main geometric characteristics. The smoothed data is used to reconstruct the river geometry and generate calculation mesh. The mesh is a two-dimensional structured grid with several possible leaking points along the actual crude oil transportation pipeline passing through the river. A multi-fluid MIXTURE model is used to simulate the crude oil spreading process on the water surface, meaning crude oil blending in the flowing water. Cases with a leaking mass flow rate of 240 kg/s and a river flow velocity of 1.58 m/s are simulated for 10 possible leaking sources on the traversing pipeline. The effect of leaking locations and river channel bending on crude oil spreading on river surface were significant according to the simulation results. Sudden widening river channel may result in vortexes and slightly delays the crude oil spreading. The simulated data could be used to make the rescue strategy of crude oil leaking in this specific river.

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Multi-Criteria Decision Making for Vulnerability Mapping of Flood Hazard: A Case Study of Pune City

10.21523/gcj5.18020105 ◽

2019 ◽

Vol 2 (1) ◽

pp. 41-52

Author(s):

Nitin Mundhe

Keyword(s):

Decision Making ◽

Flood Hazard ◽

Geographical Information ◽

Multi Criteria Decision Making ◽

Flood Hazards ◽

Very High Frequency ◽

Flood Vulnerability ◽

Natural Risk ◽

The Town

Floods are natural risk with a very high frequency, which causes to environmental, social, economic and human losses. The floods in the town happen mainly due to human made activities about the blockage of natural drainage, haphazard construction of roads, building, and high rainfall intensity. Detailed maps showing flood vulnerability areas are helpful in management of flood hazards. Therefore, present research focused on identifying flood vulnerability zones in the Pune City using multi-criteria decision-making approach in Geographical Information System (GIS) and inputs from remotely sensed imageries. Other input data considered for preparing base maps are census details, City maps, and fieldworks. The Pune City classified in to four flood vulnerability classes essential for flood risk management. About 5 per cent area shows high vulnerability for floods in localities namely Wakdewadi, some part of the Shivajinagar, Sangamwadi, Aundh, and Baner with high risk.

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Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

Sriwijaya Journal of Environment ◽

10.22135/sje.2021.6.2.59-69 ◽

2021 ◽

Vol 6 (2) ◽

pp. 59-69

Author(s):

Husna Fauzia ◽

◽

Eka Cahyaningsih ◽

Hery Hariyanto ◽

Satya Nugraha ◽

...

Keyword(s):

Land Use ◽

Spatial Modeling ◽

Flood Risk ◽

Flood Hazard ◽

Risk Level ◽

Flood Hazards ◽

Risk Area ◽

Flood Peak ◽

Risk Levels ◽

Central Java

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled landuse changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No.328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, potential flood hazards, and flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village.

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GIS based Flood Vulnerability Studies for Ife Central Local Government Area, Osun State, Nigeria

Nigerian Journal of Environmental Sciences and Technology - March 2018 ◽

10.36263/nijest.2020.01.0184 ◽

2020 ◽

Vol 4 (1) ◽

pp. 160-171

Author(s):

V.A. Ijaware

Keyword(s):

Local Government ◽

Flood Hazard ◽

Pairwise Comparison ◽

Tropical Rainfall Measuring Mission ◽

Satellite System ◽

Comparison Method ◽

Local Government Area ◽

Landsat 8 ◽

Flood Hazards ◽

Flood Vulnerability

Flood has negatively affected Ife Central Local Government Area of Osun State, Nigeria. This work is aimed at mapping the vulnerability of the area to flood. Its objectives addressed the ranking of various natural and artificial factors causing flood, the determination and delineation of vulnerability to flood in the study area. Using remote sensing and GIS techniques, coordinates of flooded sites were acquired with Global Navigation Satellite System receiver; Landsat 8 data were acquired from the USGS website. To map land use, elevation data were acquired from the Shuttle Radar Topographic Mission Digital Elevation Models, soil data was obtained from the Nigerian Geological Survey website, and rainfall data was acquired from Tropical Rainfall Measuring Mission satellit. Using Pairwise Comparison, the various weights of factors constituting flood in the area were acquired. Weighted Linear Combination and Analytical Hierarchical Process was used in producing the flood hazard and flood vulnerability maps. ArcGIS 10.2 Software was used in spatial and attribute data acquisition, processing, and information presentation. The Pairwise Comparison method adopted was validated and observed to have a consistency ration of 0.003. Results obtained show that 9.2% of the study area is highly prone to flood hazards 20.4% is prone to flood hazard and 44.3% is moderately prone to flood hazard. The method adopted correctly identifies all existing flood incidence areas within the flood- prone areas in the hazard map. The maps produced will serve as an effective tool to aid the prevention and mitigation of flood disaster in the flood-prone area.

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