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.

Application of risk based approach to flood risk assessment in urban areas

2012 ◽  
Author(s):  
T Rashidul Kabir ◽  
B Gersonius ◽  
C Zevenbergen ◽  
P van Gelder ◽  
Mohammad Shah
Keyword(s):  
Risk Assessment ◽  
Flood Risk ◽  
Urban Areas ◽  
Flood Risk Assessment

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 Flood Risk Management Methodology for Lakes and Adjacent Areas: The Lake Pamvotida Paradigm

Proceedings ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 21
Author(s):  
George Papaioannou ◽  
Athanasios Loukas ◽  
Lampros Vasiliades
Keyword(s):  
Risk Management ◽  
Natural Hazards ◽  
Flood Risk ◽  
Urban Areas ◽  
Hydrologic Modeling ◽  
Flood Risk Management ◽  
Flood Inundation ◽  
Hydrodynamic Simulations ◽  
Flood Inundation Modeling ◽  
Inundation Modeling

In recent decades, natural hazards have caused major disasters in natural and man-made environments. Floods are one of the most devasting natural hazards, with high levels of mortality, destruction of infrastructure, and large financial losses. This study presents a methodological approach for flood risk management at lakes and adjacent areas that is based on the implementation of the EU Floods Directive (2007/60/EC) in Greece. Contemporary engineering approaches have been used for the estimation of the inflow hydrographs. The hydraulic–hydrodynamic simulations were implemented in the following order: (a) hydrologic modeling of lake tributaries and estimation flood flow inflow to the lake, (b) flood inundation modeling of lake tributaries, (c) simulation of the lake as a closed system, (d) simulation of the lake outflows to the adjacent areas, and (e) simulation of flood inundation of rural and urban areas adjacent to the lake. The hydrologic modeling was performed using the HEC-HMS model, and the hydraulic-hydrodynamic simulations were implemented with the use of the two-dimensional HEC-RAS model. The simulations were applied to three soil moisture conditions (dry, medium and wet) and three return periods (T = 50, T = 100 and T = 1000 years) and a methodology was followed for the flood inundation modeling in urban areas. Upper and lower estimates on water depths, flow velocities and inundation areas are estimated for all inflow hydrographs and for varying roughness coefficient values. The proposed methodology presents the necessary steps and the results for the assessment of flood risk management and mapping for lake and adjacent urban and rural areas. The methodology was applied to Lake Pamvotida in Epirus, Greece, Ioannina.

scholarly journals A Methodological Approach to Municipal Pluvial Flood Risk Assessment Based on a Small City Case Study

2020 ◽  
Vol 12 (24) ◽  
pp. 10487
Author(s):  
Felix Julian Othmer ◽  
Dennis Becker ◽  
Laura Miriam Schulte ◽  
Stefan Greiving
Keyword(s):  
Risk Assessment ◽  
Flood Risk ◽  
Urban Areas ◽  
Heavy Rainfall ◽  
Methodological Approach ◽  
Flood Risk Assessment ◽  
Methodical Approach ◽  
Pluvial Flooding ◽  
Research Procedure ◽  
Urban Pluvial Flooding

Urban flooding caused by heavy rainfall confronts cities worldwide with new challenges. Urban flash floods lead to considerable dangers and risks. In cities and urban areas, the vulnerability to pluvial flooding is particularly high. In order to be able to respond to heavy rainfall events with adaptation strategies and measures in the course of urban development, the spatial hazards, vulnerabilities and risks must first be determined and evaluated. This article shows a new, universally applicable methodical approach of a municipal pluvial flood risk assessment for small and medium-sized cities. We follow the common approaches to risk and vulnerability analyses and take into account current research approaches to heavy rainfall and urban pluvial flooding. Based on the intersection of the hazard with the vulnerability, the pluvial flood risk is determined. The aim of the present pluvial flood risk assessment was to identify particularly affected areas in the event of heavy rainfall in the small German city of Olfen. The research procedure and the results have been coordinated with the city’s administration within the framework of a real laboratory. In the course of the science–policy cooperation, it was ensured that the results could be applied appropriately in urban developments.

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