scholarly journals Risk-Based and Hydrodynamic Pluvial Flood Forecasts in Real Time

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1895
Author(s):  
Julian Hofmann ◽  
Holger Schüttrumpf
Keyword(s):  
Real Time ◽  
Flood Risk ◽  
High Efficiency ◽  
Computation Time ◽  
Warning Systems ◽  
Hydrodynamic Models ◽  
Model Concept ◽  
Urban Flood ◽  
Real Time Simulations ◽  
The City

The effective forecast and warning of pluvial flooding in real time is one of the key elements and remaining challenges of an integrated urban flood risk management. This paper presents a new methodology for integrating risk-based solutions and 2D hydrodynamic models into the early warning process. Whereas existing hydrodynamic forecasting methods are based on rigid systems with extremely high computational demands, the proposed framework builds on a multi-model concept allowing the use of standard computer systems. As a key component, a pluvial flood alarm operator (PFA-Operator) is developed for selecting and controlling affected urban subcatchment models. By distributed computing of hydrologic independent models, the framework overcomes the issue of high computational times of hydrodynamic simulations. The PFA-Operator issues warnings and flood forecasts based on a two-step process: (1) impact-based rainfall thresholds for flood hotspots and (2) hydrodynamic real-time simulations of affected urban subcatchments models. Based on the open-source development software Qt, the system can be equipped with interchangeable modules and hydrodynamic software while building on the preliminary results of flood risk analysis. The framework was tested using a historic pluvial flood event in the city of Aachen, Germany. Results indicate the high efficiency and adaptability of the proposed system for operational warning systems in terms of both accuracy and computation time.

scholarly journals Framework for Offline Flood Inundation Forecasts for Two-Dimensional Hydrodynamic Models

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 346 ◽  
Author(s):  
Punit Bhola ◽  
Jorge Leandro ◽  
Markus Disse
Keyword(s):  
Real Time ◽  
Warning System ◽  
Flood Inundation ◽  
Hydrological Models ◽  
Hydrodynamic Models ◽  
Database Queries ◽  
Inundation Maps ◽  
Online Maps ◽  
The City ◽  
Selection Of

The paper presents a new methodology for hydrodynamic-based flood forecast that focuses on scenario generation and database queries to select appropriate flood inundation maps in real-time. In operational flood forecasting, only discharges are forecasted at specific gauges using hydrological models. Hydrodynamic models, which are required to produce inundation maps, are computationally expensive, hence not feasible for real-time inundation forecasting. In this study, we have used a substantial number of pre-calculated inundation maps that are stored in a database and a methodology to extract the most likely maps in real-time. The method uses real-time discharge forecast at upstream gauge as an input and compares it with the pre-recorded scenarios. The results show satisfactory agreements between offline inundation maps that are retrieved from a pre-recorded database and online maps, which are hindcasted using historical events. Furthermore, this allows an efficient early warning system, thanks to the fast run-time of the proposed offline selection of inundation maps. The framework is validated in the city of Kulmbach in Germany.

scholarly journals Urban flood modelling in Qiqihar city based on MIKE flood

2020 ◽  
Vol 383 ◽  
pp. 185-192
Author(s):  
Jiahong Liu ◽  
Zejin Li ◽  
Weiwei Shao ◽  
Dianyi Yan ◽  
Chao Mei
Keyword(s):  
Water Level ◽  
River Basin ◽  
Return Period ◽  
Flood Risk ◽  
Main Stream ◽  
Urban Flood ◽  
Songhua River ◽  
Mike Flood ◽  
The City ◽  
Flood Diversion

Abstract. Qiqihar is a significant city on the Nen River in China, which is the main stream of the Songhua River basin. The length of the return period of Qiqihar's flood control design standard is fifty years. If a 100-year flood event happened, Qiqihar would face the risk of a burst levee. To quantitatively evaluate flood risk to the city from a burst levee or proactive flood diversion, a model for analysing flood submergence from a burst levee in the City of Qiqihar is established based on MIKE Flood. The model integrates one- and two-dimensional hydrodynamic models to implement coupled simulation. The terrain data are from city elevation data on a scale of 1:10 000. Following local modifications made based on survey data, such as on levees, roads, and buildings, a 20 m × 20 m grid of terrain data was formed as the terrain input of the model. The model simulates the water level of Nen River and the flood path, submerged time/depth/area, and duration in floodplain under three scenarios: baseline, proactive downstream flood diversion, and an upstream levee burst under a flood with a one hundred-year return period. Proactive downstream flood diversion can reduce the maximum water level by 0.068 m and correspondingly decrease peak flood flow by 1120 m3 s−1. These results provide basic information to support urban flood risk analysis and flood dispatching and management across the whole river basin.

scholarly journals Climate Justice Planning in Global South: Applying a Coupled Nature–Human Flood Risk Assessment Framework in a Case for Ho Chi Minh City, Vietnam

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2021
Author(s):  
Chen-Fa Wu ◽  
Szu-Hung Chen ◽  
Ching-Wen Cheng ◽  
Luu Van Thong Trac
Keyword(s):  
Flood Risk ◽  
Flood Hazard ◽  
Climate Justice ◽  
Ho Chi Minh City ◽  
Flood Risk Assessment ◽  
Urban Floods ◽  
Flood Vulnerability ◽  
Urban Flood ◽  
Vulnerability Map ◽  
The City

Developing countries in the global south that contribute less to climate change have suffered greater from its impacts, such as extreme climatic events and disasters compared to developed countries, causing climate justice concerns globally. Ho Chi Minh City has experienced increased intensity and frequency of climate change-induced urban floods, causing socio-economic damage that disturbs their livelihoods while urban populations continue to grow. This study aims to establish a citywide flood risk map to inform risk management in the city and address climate justice locally. This study applied a flood risk assessment framework integrating a coupled nature–human approach and examined the spatial distribution of urban flood hazard and urban flood vulnerability. A flood hazard map was generated using selected morphological and hydro-meteorological indicators. A flood vulnerability map was generated based on a literature review and a social survey weighed by experts’ priorities using the Fuzzy Delphi Method and Analytic Network Process. Vulnerability indicators including demographic characteristics, infrastructure, and land use patterns were used to generate a flood vulnerability map. The results illustrate that almost the entire central and northeastern parts of the city are at high flood risk, whereas the western part is at low flood risk. The findings have implications in urban planning via identifying risk hot spots in order to prioritize resources for mitigating hazards and enhancing community resilience to urban floods.

scholarly journals Real-time urban flood forecasting and modelling – a state of the art

2013 ◽  
Vol 15 (3) ◽  
pp. 717-736 ◽  
Author(s):  
Justine Henonin ◽  
Beniamino Russo ◽  
Ole Mark ◽  
Philippe Gourbesville
Keyword(s):  
Real Time ◽  
Flood Risk ◽  
Urban Areas ◽  
Urban Drainage ◽  
Flood Forecast ◽  
Coupled Models ◽  
Urban Flood ◽  
Maximum Rainfall ◽  
One Dimensional ◽  
Drainage Networks

All urban drainage networks are designed to manage a maximum rainfall. This situation implies an accepted flood risk for any greater rainfall event. This risk is often underestimated as factors such as city growth and climate change are ignored. But even major structural changes cannot guarantee that urban drainage networks would cope with all future rain events. Thus, being able to forecast urban flooding in real time is one of the main issues of integrated flood risk management. Runoff and hydraulic models can be essential elements of flood forecast systems, as an active part of the system or as studying tools. This paper gives an overview of current available options for pluvial flood modelling in urban areas, from basic estimations with a one-dimensional urban drainage model to detailed flood process representation with one dimensional–two dimensional hydrodynamic coupled models. Each type of modelling solution is described with pros and cons regarding urban flood analysis. The paper then elaborates on real-time flood forecast systems and the influence of their main components. A classification of real-time urban flood systems is given based on the use of urban models, i.e. empirical scenarios, pre-simulated scenarios and real-time simulations. A review of existing operational systems is done using this classification.

scholarly journals A Simple GIS-Based Model for Urban Rainstorm Inundation Simulation

2019 ◽  
Vol 11 (10) ◽  
pp. 2830 ◽  
Author(s):  
Xianhong Meng ◽  
Min Zhang ◽  
Jiahong Wen ◽  
Shiqiang Du ◽  
Hui Xu ◽  
...  
Keyword(s):  
Input Data ◽  
High Efficiency ◽  
Surface Flow ◽  
Urban Flooding ◽  
Distributed Hydrological Model ◽  
Hydrodynamic Models ◽  
Drainage Flow ◽  
Rapid Urbanization ◽  
Urban Flood ◽  
Inundation Simulation

With rapid urbanization, floods that occur are more frequently associated with non-riverine, urban flooding. Reliable and efficient simulation of rainstorm inundation in an urban environment is profound for risk analysis and sustainable development. Although sophisticated hydrodynamic models are now available to simulate the urban flooding processes with a high accuracy, the complexity and heavy computation requirement render these models difficult to apply. Moreover, a large number of input data describing the complex urban underlying surfaces is required to setup the models, which are typically unavailable in reality. In this paper, a simple and efficient urban rainstorm inundation simulation method, named URIS, was developed based on a geographic information system (GIS) with limited input data. The URIS method is a simplified distributed hydrological model, integrating three components of the soil conservation service (SCS) module, surface flow module, and drainage flow module. Cumulative rainfall-runoff, output from the SCS model, feeds the surface flow model, while the drainage flow module is an important waterlogging mitigation measure. The central urban area of Shanghai in China was selected as a study case to calibrate and verify the method. It was demonstrated that the URIS is capable of characterizing the spatiotemporal dynamic processes of urban inundation and drainage under a range of scenarios, such as different rainstorm patterns with varying return periods and different alterations of drainage diameters. URIS is therefore characterized with high efficiency, reasonable data input, and low hardware requirements and should be an alternative to hydrodynamic models. It is useful for urgent urban flood inundation estimation and is applicable for other cities in supporting emergency rescue and sustainable urban planning.

scholarly journals Dynamic Flood Inundation Forecast for the City of Kulmbach Using Offline Two-Dimensional Hydrodynamic Models

10.29007/c4gq ◽  
2018 ◽  
Author(s):  
Punit Bhola ◽  
Jorge Leandro ◽  
Iris Konnerth ◽  
Kanwal Amin ◽  
Markus Disse
Keyword(s):  
Real Time ◽  
Dynamic Models ◽  
Water Levels ◽  
Flood Inundation ◽  
Hydrological Models ◽  
Hydrodynamic Models ◽  
Database Queries ◽  
Inundation Maps ◽  
Inundation Map ◽  
The City

The paper presents a new methodology for hydrodynamic-based flood forecast focusing on sce- nario generation and database queries to select the appropriate flood inundation map in real-time. In operational flood forecasting, discharges are forecast at specific gauges using hydrological models. The water levels are obtained from a rating curve designed for each respective gauge. Particularly for higher discharges when the flow over-spills the side banks, these curves are highly uncertain. Hy- drodynamic models are then required to produce realistic inundation maps and water levels. Hydro- dynamic models are computationally expensive and therefore not feasible for real-time forecasting. Alternatively, pre-calculated inundation maps can be stored in a database which contains a substantial number of scenarios, and used for extracting the most likely map in real-time. This study investigates the application of offline inundation forecast in the city Kulmbach in Germany.

scholarly journals Real-time Prediction of Urban Inundation based on SWMM 1D-1D Model

2020 ◽  
Vol 20 (1) ◽  
pp. 401-411
Author(s):  
Jong Kyung Jang ◽  
Min Ki Park ◽  
Na Eun Lee ◽  
Jae Min Lee ◽  
Dong Min Yang
Keyword(s):  
Real Time ◽  
Model Simulation ◽  
Flood Damage ◽  
Two Dimensional ◽  
Flood Prediction ◽  
Urban Flood ◽  
1D Model ◽  
Simulation Results ◽  
Real Time Simulations ◽  
2D Model

The concept of a Major/Minor system was applied to use urban flood prediction techniques, based on rainfall forecasts and real-time simulations, to reduce flood damage, by notifying a possible flood risk in advance. The SWMM one dimensional (1D)-two dimensional (2D) model has become the standard approach used in urban flood modeling, as it can realistically express the interaction between drainage networks and road surfaces. However, it is limited to the flood analysis of small areas due to its two-dimensional model characteristics, such as its long simulation time. Therefore, the SWMM 1D-1D model, which is fast enough to be applied to real-time simulations, is applied to real-time flood forecasting. To improve the accuracy of the model, SWMM 1D-1D model was calibrated using the SWMM 1D-2D model simulation results, and the SWMM 1D-1D model simulation results were extracted using the SWMM5 DLL and EXCEL VBA to analyze the flood situation. Finally, the applicability of the SWMM 1D-1D model was reviewed based on a rainfall event that occurred on 25 August 2014, assuming an hour of predicted rainfall.

scholarly journals Factorisation Path Based Refactorisation for High-Performance LU Decomposition in Real-Time Power System Simulation

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7989
Author(s):  
Jan Dinkelbach ◽  
Lennart Schumacher ◽  
Lukas Razik ◽  
Andrea Benigni ◽  
Antonello Monti
Keyword(s):  
Power Systems ◽  
Real Time ◽  
Decomposition Method ◽  
High Performance ◽  
Computation Time ◽  
Lu Decomposition ◽  
Nonlinear Component ◽  
Time Requirements ◽  
Component Models ◽  
Real Time Simulations

The integration of renewable energy sources into modern power systems requires simulations with smaller step sizes, larger network models and the incorporation of complex nonlinear component models. These features make it more difficult to meet computation time requirements in real-time simulations and have motivated the development of high-performance LU decomposition methods. Since nonlinear component models cause numerical variations in the system matrix between simulation steps, this paper places a particular focus on the recomputation of LU decomposition, i.e., on the refactorisation step. The main contribution is the adoption of a factorisation path algorithm for partial refactorisation, which takes into account that only a subset of matrix entries change their values. The approach is integrated into the modern LU decomposition method NICSLU and benchmarked against the methods SuperLU and KLU. A performance analysis was carried out considering benchmark as well as real power systems. The results show the significant speedup of refactorisation computation times in use cases involving system matrices of different sizes, a variety of sparsity patterns and different ratios of numerically varying matrix entries. Consequently, the presented high-performance LU decomposition method can assist in meeting computation time requirements in real-time simulations of modern power systems.

scholarly journals A Framework for Risk-Based Assessment of Urban Floods in Coastal Cities

2021 ◽  
Author(s):  
M. Dinesh Kumar ◽  
Shubham Tandon ◽  
Nitin Bassi ◽  
Pradipta Kumar Mohanty ◽  
Saurabh Kumar ◽  
...  
Keyword(s):  
High Risk ◽  
Flood Risk ◽  
Risk Index ◽  
Progressive Increase ◽  
Urban Floods ◽  
Urban Flood ◽  
Coastal Cities ◽  
Index Value ◽  
The City ◽  
Urban Flood Risk

Abstract Many coastal cities in developing countries are at the risk of flooding due to a progressive increase in the built-up areas and poor management of stormwater. The flooding situation in coastal cities gets accentuated further due to climate induced natural disasters such as cyclones and climate change induced sea-level rise that adversely impact the city’s natural drainage potential. This study developed a composite urban flood risk index consisting of three sub-indices and 20 key natural, physical, social, and economic influencing variables for a coastal city (i.e. Cuttack) in eastern India, the intensity of storm runoff being one among the many. The intensity-duration-frequency curve developed shows that the city can experience floods with a peak discharge of 1,320 cubic metre per second every alternate year for a rainfall intensity of 2-hour duration. The urban flood risk index computed for all the city wards shows that out of the 59 wards, only one ward has low flood risk (index value < 0.40) and 20 wards are at high risk (index value 0.55 and above) from the urban flood. Thereafter, factors leading to high risk due to urban floods were identified and the institutional capacities available with the urban utility for fighting floods analyzed.

scholarly journals Effectiveness of Nature-Based Solutions on Pluvial Flood Hazard Mitigation: The Case Study of the City of Eindhoven (The Netherlands)

Resources ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 24
Author(s):  
Sandra Costa ◽  
Rik Peters ◽  
Ricardo Martins ◽  
Luuk Postmes ◽  
Jan Jacob Keizer ◽  
...  
Keyword(s):  
The Netherlands ◽  
Flood Risk ◽  
Hydrological Cycle ◽  
Risk Mitigation ◽  
Flood Hazard ◽  
Urban Flood ◽  
Storm Intensity ◽  
Impervious Area ◽  
Urban Catchments ◽  
The City

Urbanization leads to changes in the surface cover that alter the hydrological cycle of cities, particularly by increasing the impervious area and, thereby, reducing the interception, storage and infiltration capacity of rainwater. Nature-based solutions (NBS) can contribute to flood risk mitigation in urbanized areas by restoring hydrological functions. However, the effects of NBS on flood risk mitigation are complex and can differ substantially with the type of the NBS. Therefore, the effectiveness of NBS at the urban catchment scale is still subject to much debate, especially at the scale of urban catchments. In this study, the effects of different NBS on urban flood mitigation were evaluated for the city of Eindhoven in The Netherlands, as it has a history of urban flood events. To this end, various NBS scenarios were defined by municipal stakeholders and their impacts modelled with the numerical model Infoworks ICM. This was done for design storms with short, medium and long return periods (5, 10 and 100 years). Overall, the simulated NBS were effective in flood risk mitigation, reducing the flooded area as well as flood depth. The effectiveness of the individual NBS scenarios, however, depended strongly on the location and extension of the NBS, as well as on storm intensity. The effectiveness tended to increase with the increase in NBS surface area, while it tended to decrease with increasing storm intensity and, hence, return period. The NBS solution increasing street water storage was revealed to be more effective than those involving green car parks and green roofs. This study showed that numerical flooding models can be useful tools to assess the effects of NBS to reduce flood extent, water depth and/or velocity, providing insights that can support city planners to design and compare alternative strategies and plans for urban flood risk mitigation.

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