scholarly journals A GIS-Based Hydrological Modeling Approach for Rapid Urban Flood Hazard Assessment

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1483
Author(s):  
Qianqian Zhou ◽  
Jiongheng Su ◽  
Karsten Arnbjerg-Nielsen ◽  
Yi Ren ◽  
Jinhua Luo ◽  
...  
Keyword(s):  
Large Scale ◽  
Hydrological Modeling ◽  
Performance Indicator ◽  
Flood Hazard ◽  
Flood Mapping ◽  
Hazard Mapping ◽  
Flood Hazards ◽  
Topographic Wetness Index ◽  
Urban Flood ◽  
Mapping Techniques

Urban floods are detrimental to societies, and flood mapping techniques provide essential support for decision-making on the better management of flood risks. This study presents a GIS-based flood characterization methodology for the rapid and efficient identification of urban flood-prone areas, which is especially relevant for large-scale flood hazards and emergency assessments for data-scarce studies. The results suggested that optimal flood mapping was achieved by adopting the median values of the thresholds for local depression extraction, the topographic wetness index (TWI) and aggregation analyses. This study showed the constraints of the depression extraction and TWI methods and proposed a methodology to improve the performance. A new performance indicator was further introduced to improve the evaluation ability of hazard mapping. It was shown that the developed methodology has a much lower demand on the data and computation efforts in comparison to the traditional two-dimensional models and, meanwhile, provides relatively accurate and robust assessments of flood hazards.

An enhanced inundation method for urban flood hazard mapping at the large catchment scale

2019 ◽  
Vol 571 ◽  
pp. 873-882 ◽  
Author(s):  
Gang Zhao ◽  
Zongxue Xu ◽  
Bo Pang ◽  
Tongbi Tu ◽  
Liyang Xu ◽  
...  
Keyword(s):  
Flood Hazard ◽  
Hazard Mapping ◽  
Catchment Scale ◽  
Urban Flood ◽  
Large Catchment

Urban flood hazard mapping using a hydraulic–GIS combined model

2020 ◽  
Vol 100 (3) ◽  
pp. 1089-1104 ◽  
Author(s):  
Boyu Feng ◽  
Jinfei Wang ◽  
Ying Zhang ◽  
Brent Hall ◽  
Chuiqing Zeng
Keyword(s):  
Flood Hazard ◽  
Hazard Mapping ◽  
Combined Model ◽  
Urban Flood

scholarly journals A comparative analysis of 3-D representations of urban flood map in virtual environments for hazard communication purposes

2018 ◽  
Vol 40 ◽  
pp. 06037 ◽  
Author(s):  
Rosa De Santis ◽  
Francesco Macchione ◽  
Pierfranco Costabile ◽  
Carmelina Costanzo
Keyword(s):  
Comparative Analysis ◽  
Water Level ◽  
Laser Scanning ◽  
Flood Hazard ◽  
Flood Hazards ◽  
Urban Flood ◽  
Hazard Communication ◽  
The Public ◽  
The Individual ◽  
The Impact

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.

scholarly journals Urban Flood Hazard Modeling Using Self-Organizing Map Neural Network

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2370 ◽  
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.

scholarly journals Urban flood hazard mapping using change detection on wetness transformed images

2016 ◽  
pp. 1-10 ◽  
Author(s):  
Arpit Aggarwal ◽  
Farhat Rafique ◽  
Edida Rajesh ◽  
Sirajuddin Ahmed
Keyword(s):  
Change Detection ◽  
Flood Hazard ◽  
Hazard Mapping ◽  
Urban Flood

scholarly journals Effects of rating-curve uncertainty on probabilistic flood mapping

2012 ◽  
Vol 9 (8) ◽  
pp. 9809-9845 ◽  
Author(s):  
A. Domeneghetti ◽  
S. Vorogushyn ◽  
A. Castellarin ◽  
B. Merz ◽  
A. Brath
Keyword(s):  
Boundary Conditions ◽  
Confidence Intervals ◽  
Flood Risk ◽  
Flood Hazard ◽  
Assessment Model ◽  
Flood Mapping ◽  
Hazard Mapping ◽  
Rating Curve ◽  
Sources Of Uncertainty ◽  
Definition Of

Abstract. Comprehensive flood risk assessment studies should quantify the global uncertainty in flood hazard estimation, for instance by mapping inundation extents together with their confidence intervals. This appears of particular importance in case of flood hazard assessments along dike-protected reaches where the possibility of occurrence of dike failures may considerably enhance the uncertainty. We present a methodology to derive probabilistic flood maps in dike-protected flood prone areas, where several sources of uncertainty are taken into account. In particular, this paper focuses on a 50 km reach of River Po (Italy) and three major sources of uncertainty in hydraulic modelling and flood mapping: uncertainties in the (i) upstream and (ii) downstream boundary conditions, and (iii) uncertainties in dike failures. Uncertainties in the definition of upstream boundary conditions (i.e. design-hydrographs) are assessed by applying different bivariate copula families to model the frequency regime of flood peaks and volumes. Uncertainties in the definition of downstream boundary conditions are characterised by associating the rating-curve used as downstream boundary condition with confidence intervals which reflect discharge measurements errors and interpolation errors. The effects of uncertainties in boundary conditions and randomness of dike failures are assessed by means of the Inundation Hazard Assessment Model (IHAM), a recently proposed hybrid probabilistic-deterministic model that considers three different failure mechanisms: overtopping, piping and micro-instability due to seepage. The results of the study show that the IHAM-based analysis enables probabilistic flood hazard mapping and provides decision makers with a fundamental piece of information for devising and implementing flood risk mitigation strategies in the presence of various sources of uncertainty.

scholarly journals SUITABLE DEM ASSESSMENT STUDY FOR DATA SCARCE CITIES TOWARDS URBAN EXTREME AND NUISANCE FLOOD MAPPING

2021 ◽  
Vol V-4-2021 ◽  
pp. 161-168
Author(s):  
A. Akkimi ◽  
S. Dutta
Keyword(s):  
High Resolution ◽  
Open Source ◽  
Developed Countries ◽  
Flood Mapping ◽  
Topographic Wetness Index ◽  
Flood Modeling ◽  
Alos Palsar ◽  
Urban Flood ◽  
Medium Resolution ◽  
Vertical Accuracy

Abstract. The high-resolution accurate topography data should be used for extreme and nuisance flood inundation modeling and mapping in cities, but not available for many cities, including most developed countries. It is necessary to study and identify an alternate open-source topographic model that satisfies high-resolution topography datasets’ conditions. We analyzed the open-source DEMs visually, elevation histogram statistics, streams and watershed identification, contour statistics, Topographic Wetness Index, and vertical accuracy of other medium-resolution DEMs compared with high-resolution LiDAR data over New York City to determine alternative open-source Digital Elevation Model in the context of urban flood modeling. In high urban sprawl areas, in the context of flood mapping, our findings have shown that the medium resolution DEMs predicted similar to high-resolution DEMs with the same linear errors around RMSE 25–35ft and LE90 30–40ft. Overall, the ALOS AW3D performed better than other open-source DEMs. Even though SRTM predicted well, it inducted smoothness in DEM where more buildings were located. It noted that ALOS PALSAR DEM is not suitable for any urban studies. ASTER DEM has also shown good agreement with LiDAR and observed elevations, but it induced by noise while processing. Finally, it can be suggested that the ALOS AW3D can be used as an alternative source for urban flood modeling which represented footprints of buildings even though it performed average in vertical accuracy.

Review of Flood Hazards Studies in Nepal

2020 ◽  
Vol 7 ◽  
pp. 24-32
Author(s):  
Buddhi Raj Shrestha ◽  
Raj Kumar Rai ◽  
Saroj Marasini
Keyword(s):  
Risk Assessment ◽  
Flow Model ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Monsoon Season ◽  
Hazard Mapping ◽  
Flood Hazards ◽  
Journal Articles ◽  
Inundation Mapping ◽  
Flood Disasters

Flood, a common water-induced disaster of monsoon season, is a recurring phenomenon in Nepal. It causes many deaths and injuries besides severe impacts on the vital infrastructures of the nation. This paper reviews the published national and international journal articles related to flood hazard mapping in Nepal. Desinventar database from 1971-2016 shows that Bagmati province and province 2 are more affected than other provinces in Nepal. Here we review the previous studies on flood disasters at the regional and national levels. The results show that most of the papers are based on a steady flow model for inundation mapping and more focuses on hazard analysis rather than vulnerability and risk assessment.

scholarly journals The influence of the net rainfall mixed Curve Number – Green Ampt procedure in flood hazard mapping: a case study in Central Italy

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Andrea Petroselli ◽  
Ettore Arcangeletti ◽  
Elena Allegrini ◽  
Nunzio Romano ◽  
Salvatore Grimaldi
Keyword(s):  
Flood Hazard ◽  
Central Italy ◽  
Estimation Procedure ◽  
Curve Number ◽  
Flood Mapping ◽  
Hazard Mapping ◽  
Rainfall Estimation ◽  
Infiltration Model ◽  
Conductivity Parameter ◽  
Scs Cn

A net rainfall estimation procedure, referred to as Curve-Number For Green-Ampt (CN4GA), combining the Soil Conservation Service - Curve Number (SCS-CN) method and the Green and Ampt (GA) infiltration equation was recently developed, aiming to distribute at subdaily time resolution the information provided by the SCS-CN method. The initial abstraction and the total volume of rainfall provided by the SCS-CN method are used to identify the ponding time and to quantify the hydraulic conductivity parameter of the GA equation, whereas the GA infiltration model distributes the total volume of the rainfall excess provided by the SCS-CN method. In this study we evaluate the proposed procedure with reference to a real case comparing the flood mapping obtained applying the event-based approach for two different net rainfall scenarios: the proposed CN4GA and the common SCS-CN. Results underline that the net rainfall estimation step can affect the final flood mapping result.

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