Urban flood hazard and its mitigation

The flood hazard/risk maps do not allow a non-expert audience an immediate perception of the flooding impacts. Therefore, we need to modernize maps providing new communication approaches. In this context, 3-D representations of flood inundation through emerging formats in virtual and augmented realities may be considered as a powerful tool to engage users with flood hazards. The challenge of the research is to create a virtual 3-D environment aimed at supporting the public, practitioners and decision-makers in interpreting and understanding the impact of simulated flood hazards. For this purpose, the paper aims to perform a comparative analysis of two techniques to carry out the 3-D realistic visualizations of a flood map for representing a potential flooding of the Crati River, in the old town of Cosenza (South of Italy). The first approach develops a simple and quick workflow that provides an overall look at a neighbourhood level, but reveals some limits in water level visualization at the individual buildings scale. The second one requires additional terrestrial laser scanning (TLS) acquisition and overcomes some limits of the first approach, by providing a visual insight about water level close to building façades.

Download Full-text

Assessing the impact of topography and land cover data resolutions on two-dimensional HEC-RAS hydrodynamic model simulations for urban flood hazard analysis

Natural Hazards ◽

10.1007/s11069-020-03906-z ◽

2020 ◽

Vol 101 (3) ◽

pp. 995-1017 ◽

Cited By ~ 2

Author(s):

Emrah Yalcin

Keyword(s):

Land Cover ◽

Hydrodynamic Model ◽

Flood Hazard ◽

Hazard Analysis ◽

Two Dimensional ◽

Urban Flood ◽

Model Simulations ◽

Land Cover Data ◽

The Impact

Download Full-text

Urban Flood Hazard Modeling Using Self-Organizing Map Neural Network

Water ◽

10.3390/w11112370 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2370 ◽

Cited By ~ 8

Author(s):

Rahmati ◽

Darabi ◽

Haghighi ◽

Stefanidis ◽

Kornejady ◽

...

Keyword(s):

Neural Network ◽

Flood Risk ◽

Goodness Of Fit ◽

Flood Hazard ◽

Characteristic Curve ◽

Urban Environments ◽

Hazard Mapping ◽

Self Organizing Map ◽

Urban Flood ◽

Self Organizing

Floods are the most common natural disaster globally and lead to severe damage, especially in urban environments. This study evaluated the efficiency of a self-organizing map neural network (SOMN) algorithm for urban flood hazard mapping in the case of Amol city, Iran. First, a flood inventory database was prepared using field survey data covering 118 flooded points. A 70:30 data ratio was applied for training and validation purposes. Six factors (elevation, slope percent, distance from river, distance from channel, curve number, and precipitation) were selected as predictor variables. After building the model, the odds ratio skill score (ORSS), efficiency (E), true skill statistic (TSS), and the area under the receiver operating characteristic curve (AUC-ROC) were used as evaluation metrics to scrutinize the goodness-of-fit and predictive performance of the model. The results indicated that the SOMN model performed excellently in modeling flood hazard in both the training (AUC = 0.946, E = 0.849, TSS = 0.716, ORSS = 0.954) and validation (AUC = 0.924, E = 0.857, TSS = 0.714, ORSS = 0.945) steps. The model identified around 23% of the Amol city area as being in high or very high flood risk classes that need to be carefully managed. Overall, the results demonstrate that the SOMN model can be used for flood hazard mapping in urban environments and can provide valuable insights about flood risk management.

Download Full-text

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

Natural Hazards and Earth System Science ◽

10.5194/nhess-17-205-2017 ◽

2017 ◽

Vol 17 (2) ◽

pp. 205-224 ◽

Cited By ~ 4

Author(s):

Joanne Comer ◽

Agnieszka Indiana Olbert ◽

Stephen Nash ◽

Michael Hartnett

Keyword(s):

Moving Boundary ◽

Flood Hazard ◽

Hazard Identification ◽

Water Levels ◽

Urban Flooding ◽

Coastal Zones ◽

Urban Flood ◽

Multi Scale ◽

Scale Modelling ◽

Modelling System

Abstract. 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.

Download Full-text

Urban flood hazard mapping using change detection on wetness transformed images

Hydrological Sciences Journal ◽

10.1080/02626667.2014.952638 ◽

2016 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Arpit Aggarwal ◽

Farhat Rafique ◽

Edida Rajesh ◽

Sirajuddin Ahmed

Keyword(s):

Change Detection ◽

Flood Hazard ◽

Hazard Mapping ◽

Urban Flood

Download Full-text

Methodologies to study the surface hydraulic behaviour of urban catchments during storm events

Water Science & Technology ◽

10.2166/wst.2011.174 ◽

2011 ◽

Vol 63 (11) ◽

pp. 2666-2673 ◽

Cited By ~ 17

Author(s):

M. Gómez ◽

F. Macchione ◽

B. Russo

Keyword(s):

Urban Areas ◽

Flood Hazard ◽

Spatial Density ◽

Hydraulic Efficiency ◽

Storm Events ◽

Accurate Analysis ◽

Numerical Application ◽

Urban Flood ◽

Hydraulic Behaviour ◽

Urban Catchments

A good knowledge of the hydraulic behaviour of an urban catchment and its surface drainage system is an essential requirement to guarantee traffic and pedestrian safety. In many cases, inlets have been situated according to spatial density criteria. Indeed a more rational location of inlets on urban catchments must be defined according to an accurate analysis of the relationship between street flow and inlet hydraulic efficiency. Moreover we lack specific hazard criteria in terms of the maximum acceptable flow depths and velocities on the streets that do not cause problems to pedestrians. In this paper the results of two different experimental campaigns are presented. The first was carried out to evaluate inlet hydraulic efficiency; the second was carried out to address the pedestrian stability in urban flood conditions, whose aim was to propose new hazard criteria. On the basis of the experimental results, a methodology was developed to assess flood hazard in urban areas during storm events. If a refined topographic representation of urban areas is available, a two-dimensional numerical simulation of urban flooding can be performed using complete shallow water equations. According to this approach a numerical application for flood hazard assessment in a street of Barcelona is shown.

Download Full-text