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.

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 Review article: A review and critical analysis of the efforts towards urban flood risk management in the Lagos region of Nigeria

2016 ◽  
Vol 16 (2) ◽  
pp. 349-369 ◽  
Author(s):  
U. C. Nkwunonwo ◽  
M. Whitworth ◽  
B. Baily
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Risk Mitigation ◽  
Flood Hazard ◽  
Flood Management ◽  
Flood Damage ◽  
Flood Risk Management ◽  
Management Policy ◽  
Urban Flooding ◽  
Urban Flood

Abstract. Urban flooding has been and will continue to be a significant problem for many cities across the developed and developing world. Crucial to the amelioration of the effects of these floods is the need to formulate a sound flood management policy, which is driven by knowledge of the frequency and magnitude of impacts of these floods. Within the area of flood research, attempts are being made to gain a better understanding of the causes, impacts, and pattern of urban flooding. According to the United Nations office for disaster reduction (UNISDR), flood risk is conceptualized on the basis of three integral components which are frequently adopted during flood damage estimation. These components are: probability of flood hazard, the level of exposure, and vulnerabilities of elements at risk. Reducing the severity of each of these components is the objective of flood risk management under the UNISDR guideline and idea of “living with floods”. On the basis of this framework, the present research reviews flood risk within the Lagos area of Nigeria over the period 1968–2012. During this period, floods have caused harm to millions of people physically, emotionally, and economically. Arguably over this period the efforts of stakeholders to address the challenges appear to have been limited by, amongst other things, a lack of reliable data, a lack of awareness amongst the population affected, and a lack of knowledge of flood risk mitigation. It is the aim of this research to assess the current understanding of flood risk and management in Lagos and to offer recommendations towards future guidance.

scholarly journals Using Remote Sensing Based Metrics to Quantify the Hydrological Response in a City

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1763 ◽  
Author(s):  
Charlotte Wirion ◽  
Willy Bauwens ◽  
Boud Verbeiren
Keyword(s):  
Remote Sensing ◽  
Potential Evapotranspiration ◽  
Remote Sensing Data ◽  
Hyperspectral Data ◽  
Hydrological Response ◽  
Area Index ◽  
Impervious Area ◽  
Urban Catchments ◽  
The City ◽  
Total Impervious Area

We propose a remote-sensing based metric approach to evaluate the hydrological response of highly urbanized areas and apply it to the city of Brussels. The model is set-up using 2 m resolution hyperspectral data. Next, it is upscaled to the city level, using multi-spectral Sentinel-2 data with 20 m resolution. We identify the total impervious area, the vegetation cover and the leaf area index as important metrics to derive a timeseries of spatially distributed net rainfall, runoff and infiltration from rainfall data. For the estimation of the actual evapotranspiration we use the potential evapotranspiration and the available water storage based on the interception, the depression storage and the infiltration. Additionally, we route the runoff to the outlet of selected sub-catchments. An important metric for the routing is the timing to the outlet which is approximated using the total impervious area and the hydrological distance to the outlet. We compare our approach to WetSpa model simulations and reach R 2 values of 98% for net rainfall, 95% for surface runoff, 99% for infiltration and 97% for cumulative evapotranspiration. The routing in the Watermaelbeek catchment is evaluated with discharge observations and reaches NSE values of 0.89 at a 2 m resolution and 0.88 at a 20 m resolution using an hourly timestep. At the timestep of 10 min and a 20 m resolution the NSE is reduced to 0.76. For the Roodebeek catchment we reach an NSE of 0.73 at a spatial resolution of 20 m and an hourly timestep. The results presented in this paper are optimistic for using spatial and temporal metrics retrieved from remote sensing data to quantify the water balance of urban catchments.

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 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.

Keeping Feet Dry: Rotterdam’s Experience in Flood Risk and Resilience Building

2020 ◽  
Author(s):  
Theresa Audrey O. Esteban ◽  
Jurian Edelenbos ◽  
Naomi van Stapele
Keyword(s):  
The Netherlands ◽  
Flood Risk ◽  
Risk And Resilience ◽  
Urban Resilience ◽  
Key Stakeholders ◽  
Flooding Disaster ◽  
Resilience Framework ◽  
The City ◽  
Collective Engagement ◽  
Depth Interviews

Rotterdam City in the South of Holland is one of the most vibrant cities you will find in the Netherlands. The city has gone through a transformation from the time it was bombed in the 1940s up to the time that a part of the city was flooded in 1953. Through extensive rebuilding and the Delta Plan project, the city has been well protected against any flooding disaster that may come. However, how resilient really is Rotterdam? Through in-depth interviews of key stakeholders in the City of Rotterdam, the study investigates the collective engagement in the city and how this has helped shape Rotterdam’s position in urban resilience. The study used the Collective Engagement Urban Resilience Framework as a framework to understand how disaster prone cities transform itself to become disaster resilient.

Quantification of flood hazard for the megacity of Lagos, Nigeria, by hydrodynamic simulation

2020 ◽  
Author(s):  
Tobias Pilz
Keyword(s):  
Flood Risk ◽  
Water Cycle ◽  
Flood Hazard ◽  
Storm Surges ◽  
Heavy Precipitation ◽  
Early Warning Systems ◽  
Data Availability ◽  
Hydrodynamic Simulation ◽  
Local Decision ◽  
The City

<p>Climate change leads to rising temperatures and therefore stimulates the water cycle. As a consequence, extreme events in rainfall and associated flooding are projected to increase in frequency and severity in many regions of the world. Especially in developing countries with high population growth and often unregulated settlement, flood risk may increase due to both increased flood hazard and enhanced exposure. One such example is the megacity of Lagos, Nigeria, belonging to the largest cities in Africa. Floods within the city are recurrent and caused by storm surges from the Atlantic, heavy precipitation, and river floods. Flood risk is an issue and even expected to increase due to enhanced extreme precipitation, sea level rise, enhances storm surges, as well as illegal settlement, poor management, insufficient or blocking of drainage channels, missing early warning systems, and insufficient data.</p><p>The aim of this study is to deliver a first quantification of flood hazard for the city of Lagos based on hydrodynamic simulation with the model TELEMAC-2D. A focus is put on the use of freely available data sources and the design of reproducible workflows in order to enable local decision-makers to individually apply and refine the established workflows. The biggest challenge is the generation of the model mesh as the basis for subsequent hydrodynamic modelling due to limited data availability and the size of the model domain (about 1000 km²).</p>

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