scholarly journals Ensembles of radar nowcasts and COSMO-DE-EPS for urban flood management

2018 ◽  
Vol 2017 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Alrun Jasper-Tönnies ◽  
Sandra Hellmers ◽  
Thomas Einfalt ◽  
Alexander Strehz ◽  
Peter Fröhle
Keyword(s):  
Urban Areas ◽  
Flood Management ◽  
Short Term ◽  
Ensemble Forecasts ◽  
Urban Flood ◽  
Rainfall Events ◽  
Flood Warning ◽  
Urban Catchments ◽  
Heavy Rainfall Events

Abstract Sophisticated strategies are required for flood warning in urban areas regarding convective heavy rainfall events. An approach is presented to improve short-term precipitation forecasts by combining ensembles of radar nowcasts with the high-resolution numerical weather predictions COSMO-DE-EPS of the German Weather Service. The combined ensemble forecasts are evaluated and compared to deterministic precipitation forecasts of COSMO-DE. The results show a significantly improved quality of the short-term precipitation forecasts and great potential to improve flood warnings for urban catchments. The combined ensemble forecasts are produced operationally every 5 min. Applications involve the Flood Warning Service Hamburg (WaBiHa) and real-time hydrological simulations with the model KalypsoHydrology.

scholarly journals Decision support system for urban flood management

2005 ◽  
Vol 7 (1) ◽  
pp. 3-15 ◽  
Author(s):  
A. J. Abebe ◽  
R. K. Price
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Data Acquisition ◽  
Support System ◽  
Urban Areas ◽  
Flood Management ◽  
Urban Flood ◽  
Flood Warning ◽  
Forecast Models

This paper presents the development of a decision support system (DSS) for flood warning and instantiation of restoration activities in two urban areas, the Liguria Region in Italy and the Greater Athens catchment in Greece, with the potential of extension to other locations with similar flooding problems. The tool is designed to work at the centre of a set of meteorological and hydrologic/hydraulic forecast models together with telemetric data acquisition networks. The study reveals the complexity and uncertainty involved in managing flooding in the study areas. Issues about the validity and extended benefits of the system are also discussed.

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

2011 ◽  
Vol 63 (11) ◽  
pp. 2666-2673 ◽  
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.

scholarly journals Development of Korean Nomograms for Forecasting and Alerting Debris Flows Based on Critical Accumulated Rainfall

2019 ◽  
Author(s):  
Dong-Ho Nam ◽  
Suk-Ho Lee ◽  
Byung-Sik Kim
Keyword(s):  
South Korea ◽  
Urban Areas ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Short Term ◽  
Rainfall Events ◽  
Accumulated Rainfall ◽  
Landslides And Debris Flows ◽  
Climate Events ◽  
Heavy Rains

Ongoing climate change causes abnormal climate events worldwide such as increasing temperatures and changing rainfall patterns. With South Korea facing growing damage from the increased frequency of localized heavy rains, the country is not an exception. In particular, its steep slope lands, including mountainous areas, are vulnerable to damage from landslides and debris flows. In addition, localized short-term heavy rains that occur in urban areas with extremely high intensity tend to lead a sharp increase in damage from soil-related disasters and cause huge losses of life and property. Currently, South Korea predicts landslides and debris flows using the standards for forecasting landslides and heavy rains. However, as the forecasting is conducted separately for rainfall intensity and accumulated rainfall, this lacks a technique that reflects both amount and intensity of rainfall in an episode of localized heavy rainfall. This study, therefore, aims to develop such a technique by collecting past cases of debris flow occurrences and rainfall events that accompanied debris flows to calculate the rainfall triggering index (RTI) reflecting accumulated rainfall and rainfall intensity. In addition, the RTI is converted into the critical accumulated rainfall (Rc) to use precipitation information and provide real-time forecasting. The study classifies the standards for flow debris forecasting into three levels: ALERT (10%–50%), WARNING (50%–70%), and EMERGENCY (70% or higher), to provide a nomogram for 6 hr, 12 hr, and 24 hr. As a result of applying this classification into the actual cases of Seoul, Chuncheon, and Cheongju, it is found that about 2–4 hr of response time is secured from the point of the Emergency level to the occurrence of debris flows.

scholarly journals Nature-Based Solutions in an Urban Perspective

Proceedings ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 3
Author(s):  
Sörensen
Keyword(s):  
Flood Risk ◽  
Urban Areas ◽  
Green Spaces ◽  
Wide Spread ◽  
Water Utility ◽  
Technical Problems ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Urban Catchments

The traditional engineering approach to manage urban drainage is by combined or separated sewers. In urban catchments, drainage systems may include different types of storage and detention facilities to avoid flooding from heavy rainfall. However, during recent decades, alternative ways to manage floods have evolved since traditional methods often harm the riverine ecosystems by pollution and erosion and increase the flood risk in the downstream extent of a catchment. Green spaces are important in urban areas for many different reasons: recreation, maintenance of biodiversity, city structure, cultural identity, environmental quality of the urban area, and as biological solutions to technical problems in urban areas. However, plans for urban green spaces often do not take into consideration the multiple purposes of green spaces and the relation between urban green spaces and water is only to a limited degree mentioned and discussed in such plans. Densification has become a dominating urban planning strategy, as many cities strive to reduce their negative, environmental impact. As a consequence of urban densification, the need for solid strategies to preserve, build, develop and ideally simultaneously increase the quantity (area) and quality of green and blue spaces (vegetation and surface water) in urban areas in a multifunctional manner increases. The combination of climate change adaptation, densification, pollution, the call for more green spaces, and a need to restore aging sewers, leads to strong interest in retrofitting of urban areas with nature-based solutions (NBS). Incorporation of NBS into decision-making and ways to handle integrative and multi-criteria aspects in the legal and organisational system are still to a great extent not done. The current regime for stormwater management, through piped drainage, is dominating and many cities face a lack of green spaces. Introducing more nature-based solutions is faced with barriers that are largely socio-institutional rather than technical. In this keynote session such barriers, as well as drivers, for wide-spread implementation of NBS, as well as data management strategies to help the implementation, are discussed. Based on transition theory, socio-technical transition towards wide-spread implementation of such measures were examined through interviews with municipal and water utility officials. Legal, organisational and financial changes are suggested. This keynote session also discusses urban, pluvial flooding and if NBS can be used as a strategy for resilient flood risk management. Spatial analyses of flood claims from insurance companies and the water utility company of Malmö are used to study how NBS impact flood risk.

Modeling sewage leakage to surrounding groundwater and stormwater drains

2012 ◽  
Vol 66 (12) ◽  
pp. 2659-2665 ◽  
Author(s):  
Duy Khiem Ly ◽  
Ting Fong May Chui
Keyword(s):  
Local Scale ◽  
Short Term ◽  
Modeling Framework ◽  
Rainfall Events ◽  
Sewage Pipe ◽  
Quality Of Water ◽  
Leakage Monitoring ◽  
Pipe Rehabilitation

Underground sewage pipe systems deteriorate over time resulting in cracks and joint defects. Sewage thus leaks out and contaminates the surrounding groundwater and the surface water in stormwater drains. Many studies have investigated the problem of sewage leakage but no published studies, to the best knowledge of the authors, have examined the hydrologic interactions between leaky sewage pipes, groundwater and stormwater drains. This study numerically models such interactions using generic conditions in Singapore. It first develops accurate representations of weep holes and leaky sewage pipes, and further shows the long-term and short-term system responses to rainfall events. Some of the implications include: (1) quality of water seeping into the drains tends to be low in dry years; (2) complete contaminant attenuation after pipe rehabilitation takes several years; (3) responses to rainfall events at weep holes are immediate but the effects on sewage leakage might only show up a few days later. The simulation results allow us to better understand the local-scale migration of sewage leakage from a sewage pipe to nearby stormwater drains. With calibrations and verifications with local field data, the modeling framework would be applicable and beneficial to the sewage leakage monitoring and sewage pipe rehabilitation worldwide.

scholarly journals Methodology for qualitative urban flooding risk assessment

2013 ◽  
Vol 68 (4) ◽  
pp. 829-838 ◽  
Author(s):  
João P. Leitão ◽  
Maria do Céu Almeida ◽  
Nuno E. Simões ◽  
André Martins
Keyword(s):  
Risk Assessment ◽  
Public Transportation ◽  
Flood Risk ◽  
Urban Areas ◽  
Overland Flow ◽  
Urban Flood ◽  
Rainfall Events ◽  
Transportation Services ◽  
Recent Developments ◽  
Flooding Risk

Pluvial or surface flooding can cause significant damage and disruption as it often affects highly urbanised areas. Therefore it is essential to accurately identify consequences and assess the risks associated with such phenomena. The aim of this study is to present the results and investigate the applicability of a qualitative flood risk assessment methodology in urban areas. This methodology benefits from recent developments in urban flood modelling, such as the dual-drainage modelling concept, namely one-dimensional automatic overland flow network delineation tools (e.g. AOFD) and 1D/1D models incorporating both surface and sewer drainage systems. To assess flood risk, the consequences can be estimated using hydraulic model results, such as water velocities and water depth results; the likelihood was estimated based on the return period of historical rainfall events. To test the methodology two rainfall events with return periods of 350 and 2 years observed in Alcântara (Lisbon, Portugal) were used and three consequence dimensions were considered: affected public transportation services, affected properties and pedestrian safety. The most affected areas in terms of flooding were easily identified; the presented methodology was shown to be easy to implement and effective to assess flooding risk in urban areas, despite the common difficulties in obtaining data.

scholarly journals Evaluation of ECMWF's forecasting system for probabilistic urban flood prediction: a case study in Mexico City

2021 ◽  
Author(s):  
Marco R. López ◽  
Adrián Pedrozo-Acuña ◽  
Marcela L. Severiano Covarrubias
Keyword(s):  
Mexico City ◽  
Local Level ◽  
Warning System ◽  
Precipitation Forecast ◽  
Ensemble Prediction ◽  
Forecast Horizon ◽  
Ensemble Forecasts ◽  
Flood Prediction ◽  
Urban Flood ◽  
Flood Warning

Abstract As the world continues urbanizing, including efforts to forge a new framework of urban development is necessary. Recent studies related to flood prediction and mitigation have shown that Ensemble Prediction Systems (EPSs) constitute a valuable and essential tool for an Early Warning System. However, the use of EPS for flood forecasting in urban zones has yet to be understood. This work has the objective to investigate the potential use of the Operational EPS, issued by the European Centre for Medium-Range Weather Forecasts (ECMWF), for probabilistic urban flood prediction. In this research, a precipitation forecast verification was carried out in two study zones: (1) Mexico Valley Basin and (2) Mexico City, where for the latter, forecasts were compared against real-time observed data. The results showed good forecast reliability for a rain threshold of up to 20 mm in 24-hourly accumulations, with the first 36 h of the forecast horizon being the most reliable. The EPS has sufficient resolution and precision for flood prediction in Mexico City, which represents a further step toward developing a flood warning system at the local level based on ensemble forecasts.

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