scholarly journals DEVELOPMENT OF A FLOOD RISK ASSESSMENT MODEL FOR A BRAIDED RIVER SYSTEM

2017 ◽  
pp. 25
Author(s):  
Mustafa Kemal Cambazoglu ◽  
Cheryl Ann Blain
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Channel Model ◽  
River System ◽  
Flood Risk Management ◽  
High Flow ◽  
Water Levels ◽  
Pearl River ◽  
Braided River ◽  
River Channels

The aim of this study is to construct a modeling system that will assist flood risk management strategies in a coastal plain braided river system. The model configuration consists of a hydrodynamic model (ADCIRC) of the river basin that receives tidal forcing at the open boundary and river discharge forcing at upstream flux boundary. An unstructured mesh model resolving the Pearl River channels at higher resolution from the coastline to approximately 75km inland to upstream reaches of the river has been constructed. The modeling system produces water levels and currents throughout the Lower Pearl River Basin. Initial sensitivity analysis efforts on the channel model include consideration of low-flow, average-flow, and high-flow scenarios. Model results were found to be slightly sensitive to slope of river channels and bottom friction to control stability in predictions. The model results were shown to be highly sensitive to the bathymetry of the model that controls the discharge capacity of the narrow river channels and the channel model resulted in elevated currents and water levels under high flow conditions. A channel discharge capacity analysis was conducted and the results showed the need to construct a floodplain mesh around the channel model with more realistic bathymetry and topography so that the flooding scenarios could be modeled with wetting and drying capability of ADCIRC. An initial attempt to develop such a floodplain mesh has been made with preliminary results and more comprehensive validation of the developed floodplain modeling system will extend to reproducing events associated with the historical Hurricane Isaac that impacted the region in 2012. This modeling system will provide an important tool to decision makers that could be used in future flood risk management and mitigation efforts.

scholarly journals The Value of Citizen Science for Flood Risk Reduction: Cost-benefit Analysis of a Citizen Observatory in the Brenta-Bacchiglione Catchment

2020 ◽  
Author(s):  
Michele Ferri ◽  
Uta Wehn ◽  
Linda See ◽  
Martina Monego ◽  
Steffen Fritz
Keyword(s):  
Risk Management ◽  
Citizen Science ◽  
Flood Risk ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Flood Risk Management ◽  
Water Levels ◽  
Sensor Data ◽  
Benefit Analysis ◽  
Eu Directive

Abstract. Citizen observatories are a relatively recent form of citizen science. As part of the flood risk management strategy of the Brenta-Bacchiglione catchment, a citizen observatory for flood risk management has been proposed and is currently being implemented. Citizens are involved through monitoring water levels and obstructions and providing other relevant information through mobile apps, where the data are assimilated with other sensor data in a hydrological-hydraulic model used in early warning. A cost benefit analysis of the citizen observatory was undertaken to demonstrate the value of this approach in monetary terms. Although not yet fully operational, the citizen observatory is assumed to decrease the social vulnerability of the flood risk. By calculating the hazard, exposure and vulnerability of three flood scenarios (required for flood risk management planning by the EU Directive on Flood Risk Management) with and without the proposed citizen observatory, it is possible to evaluate the benefits in terms of the average annual avoided damage costs. Although currently a hypothetical exercise, the results showed a reduction in avoided damage of 45 % compared to a business as usual scenario. Thus, linking citizen science with hydrological modelling, and to raise awareness of flood hazards, has great potential in reducing future flood risk in the Brenta-Bacchiglione catchment. Moreover, such approaches are easily transferable to other catchments.

scholarly journals A rainfall design method for spatial flood risk assessment: considering multiple flood sources

2015 ◽  
Vol 12 (8) ◽  
pp. 8005-8033 ◽  
Author(s):  
X. Jiang ◽  
H. Tatano
Keyword(s):  
Risk Assessment ◽  
Risk Management ◽  
Flood Risk ◽  
Urban Areas ◽  
Design Method ◽  
Coastal Flooding ◽  
Flood Risk Management ◽  
Flood Risk Assessment ◽  
River Channels ◽  
Critical Rainfall

Abstract. Information about the spatial distribution of flood risk is important for integrated urban flood risk management. Focusing on urban areas, spatial flood risk assessment must reflect all risk information derived from multiple flood sources: rivers, drainage, coastal flooding etc. that may affect the area. However, conventional flood risk assessment deals with each flood source independently, which leads to an underestimation of flood risk in the floodplain. Even in floodplains that have no risk from coastal flooding, flooding from river channels and inundation caused by insufficient drainage capacity should be considered simultaneously. For integrated flood risk management, it is necessary to establish a methodology to estimate flood risk distribution across a floodplain. In this paper, a rainfall design method for spatial flood risk assessment, which considers the joint effects of multiple flood sources, is proposed. The concept of critical rainfall duration determined by the concentration time of flooding is introduced to connect response characteristics of different flood sources with rainfall. A copula method is then adopted to capture the correlation of rainfall amount with different critical rainfall durations. Rainfall events are designed taking advantage of the copula structure of correlation and marginal distribution of rainfall amounts within different critical rainfall durations. A case study in the Otsu River Basin, Osaka prefecture, Japan was conducted to demonstrate this methodology.

Appraising sustainable flood risk management in the Pearl River Delta's coastal megacities: a case study of Hong Kong, China

2013 ◽  
Vol 4 (4) ◽  
pp. 390-409 ◽  
Author(s):  
F. K. S. Chan ◽  
O. A. Adekola ◽  
G. Mitchell ◽  
A. T. McDonald
Keyword(s):  
Risk Management ◽  
Hong Kong ◽  
Flood Risk ◽  
Risk Mitigation ◽  
Storm Surges ◽  
Climatic Conditions ◽  
Flood Risk Management ◽  
Pearl River ◽  
The Pearl River

The Pearl River Delta (PRD) region has experienced rapid economic and population growth in the last three decades. The delta includes coastal megacities, such as Hong Kong. These low-lying urbanised coastal regions in the PRD are vulnerable to flood risks from unpredictable climatic conditions. These can result in increasing storm surges, rising sea level and intensified rainstorms causing coastal and inland flooding, all of which impact the delta. This paper has taken the coastal megacity of Hong Kong as a case, focusing on two study sites: Shenzhen River and Tai O town, chosen for their peculiar inland and coastal flood problems. A sustainable flood risk appraisal (SFRA) template was developed against which sustainable flood risk management (FRM) practices in these sites were benchmarked. Thirty-eight stakeholders were interviewed during this research in order to understand the current FRM practices, their barriers and their constraints. It was found that FRM in the case study currently focuses on hard engineering, while neglecting other important sustainability indicators. A SFRA practice that takes public participation, equity of flood preparedness and environmental friendly into account could be effective in achieving sustainable flood risk mitigation practices in Hong Kong and other coastal cities in the PRD.

scholarly journals Large-scale stochastic flood hazard analysis applied to the Po River

2020 ◽  
Vol 104 (3) ◽  
pp. 2027-2049
Author(s):  
A. Curran ◽  
Karin De Bruijn ◽  
Alessio Domeneghetti ◽  
Federica Bianchi ◽  
M. Kok ◽  
...  
Keyword(s):  
Risk Management ◽  
Flood Risk ◽  
Large Scale ◽  
Extreme Event ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Flood Risk Management ◽  
Water Levels ◽  
Stochastic Methods ◽  
Po River

Abstract Reliable hazard analysis is crucial in the flood risk management of river basins. For the floodplains of large, developed rivers, flood hazard analysis often needs to account for the complex hydrology of multiple tributaries and the potential failure of dikes. Estimating this hazard using deterministic methods ignores two major aspects of large-scale risk analysis: the spatial–temporal variability of extreme events caused by tributaries, and the uncertainty of dike breach development. Innovative stochastic methods are here developed to account for these uncertainties and are applied to the Po River in Italy. The effects of using these stochastic methods are compared against deterministic equivalents, and the methods are combined to demonstrate applications for an overall stochastic hazard analysis. The results show these uncertainties can impact extreme event water levels by more than 2 m at certain channel locations, and also affect inundation and breaching patterns. The combined hazard analysis allows for probability distributions of flood hazard and dike failure to be developed, which can be used to assess future flood risk management measures.

scholarly journals The value of citizen science for flood risk reduction: cost–benefit analysis of a citizen observatory in the Brenta-Bacchiglione catchment

2020 ◽  
Vol 24 (12) ◽  
pp. 5781-5798
Author(s):  
Michele Ferri ◽  
Uta Wehn ◽  
Linda See ◽  
Martina Monego ◽  
Steffen Fritz
Keyword(s):  
Risk Management ◽  
Citizen Science ◽  
Flood Risk ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Flood Risk Management ◽  
Water Levels ◽  
Sensor Data ◽  
Benefit Analysis ◽  
Eu Directive

Abstract. Citizen observatories are a relatively recent form of citizen science. As part of the flood risk management strategy of the Brenta-Bacchiglione catchment, a citizen observatory for flood risk management has been proposed and is currently being implemented. Citizens are involved through monitoring water levels and obstructions and providing other relevant information through mobile apps, where the data are assimilated with other sensor data in a hydrological–hydraulic model used in early warning. A cost–benefit analysis of the citizen observatory was undertaken to demonstrate the value of this approach in monetary terms. Although not yet fully operational, the citizen observatory is assumed to decrease the social vulnerability of the flood risk. By calculating the hazard, exposure and vulnerability of three flood scenarios (required for flood risk management planning by the EU Directive on Flood Risk Management) with and without the proposed citizen observatory, it is possible to evaluate the benefits in terms of the average annual avoided damage costs. Although currently a hypothetical exercise, the results showed a reduction in avoided damage of 45 % compared to a business as usual scenario. Thus, linking citizen science and citizen observatories with hydrological modelling to raise awareness of flood hazards and to facilitate two-way communication between citizens and local authorities has great potential in reducing future flood risk in the Brenta-Bacchiglione catchment. Moreover, such approaches are easily transferable to other catchments.

scholarly journals Flood risk appraisal and management in mega-cities: a case study of practice in the Pearl River Delta, China

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
F. K. S. Chan ◽  
G. Mitchell ◽  
A. T. McDonald
Keyword(s):  
Risk Management ◽  
Hong Kong ◽  
Flood Risk ◽  
Pearl River Delta ◽  
Flood Risk Management ◽  
Pearl River ◽  
Risk Appraisal ◽  
The Pearl River Delta ◽  
The Pearl River

In recent decades, the Pearl River Delta (PRD) region has experienced strong economic and population growth. By 2050 120 million people are expected to live in the region, which currently has eleven major cities, and the emerging mega-city formed by Hong Kong, Shenzhen and Guangzhou. The populous coastal cities and low lying flood plains in the PRD experience flood risk via: (i) intense precipitation from storms, (ii) inland pluvial flooding, (iii) storm surges. Climate change, including global sea level rise forecasts of more than 1 m by 2100, mean that flood risk is expected to increase in future. Sustainable flood risk management (SFRM) must be adopted to mitigate these risks. Strategies such as the UK's ‘making space for water’ programme seek to tackle flood risk through planning, but such a strategic approach is not evident in the PRD. Recent coastal land reclamation projects in the PRD illustrate the conflict between urban growth pressure and flood risk, and that more comprehensive, or sustainable, flood risk management is not currently practiced. This paper examines flood risk management practice in the PRD. It starts with a theoretical sustainable flood risk appraisal (SFRA) template developed from literature and global best practice, against which PRD practice is benchmarked. The paper discusses a case study in Hong Kong and Shenzhen where in-depth discussions with more than 30 stakeholders were held to understand barriers and constraints to realising SFRM. This research seeks to further the practice of SFRM in the PRD, and comparable urbanising mega-deltas in the region.

The Issues and Challenges of Flood-related Agencies in Malaysia

2020 ◽  
Vol 5 (13) ◽  
pp. 285-290
Author(s):  
Nurul Ashikin Mabahwi ◽  
Hitoshi Nakamura
Keyword(s):  
Risk Management ◽  
Thematic Analysis ◽  
Flood Risk ◽  
Publishing House ◽  
Flood Risk Management ◽  
Communication Problems ◽  
Qualitative Thematic Analysis ◽  
International Publishing ◽  
The Government ◽  
Open Access Article

Objectives of this study is to identify the real issues and challenges of flood related agencies in Malaysia. By using qualitative thematic analysis, this study found that limited authorities, lack of enforcement power, lack of cooperation among agencies, lack of man-power and assets for logistics, insufficient funding for flood risk management and communication problems are the issues faced by the flood-related agencies. The government needs to solve the issues and challenges in order to strengthen the flood-related agencies capacities.Keywords: flood risk management; flood-related agencies; issues; authorityeISSN: 2398-4287 © 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v5i13.2069

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