Urban Flood Risk Management Introduction on Case Studies September 18/19, 2014
Urban Floods and Major Causes Capacity deficit of preventive infrastructures Heavy rainfall, tidal flood increases Climate change Construction of underground spaces Urban Floods Riversides lowlands development Spatial Development Urbanization / concentration of population Land use change Urban Flood Risk Management, September 18/19, 2014 2
Objectives of the Case Studies Exchange of practical experiences and knowledge dealing with urban floods Jointly elaborate strategies and measures for risk reduction for every case study To find solutions for a forward-looking, integrated flood risk management Current situation Future situations Urban Flood Risk Management, September 18/19, 2014 3
Approach Dealing with urban floods is a complex task Different causes and interaction of different damage drivers A lot of stakeholders and institutions involved: high need for coordination: Flood specialists, urban planners, local authorities, infrastructure and construction experts etc. A systematically approach is needed that: bases on a systematically risk assessment identifies the need for action (priority setting) enables an effective use of resources promotes a risk dialogue with all relevant stakeholders Urban Flood Risk Management, September 18/19, 2014 4
organization legal base Integrated Risk Management policy (vision, objectives, strategies) Urban Flood Risk Management, September 18/19, 2014 5
Case study: Risk Assessment (i) Intensity of floods for certain frequencies? What can happen? Expected damages and their distribution? Total risk? Highest risks? What is allowed to happen? What risks are accepted or what safety level should be reached? What has to be done? Strategies, measures for risk reduction? Urban Flood Risk Management, September 18/19, 2014 6
Case Study: Risk Assessment (ii) Hazards Heavy Rainfall River Flood Coastal Flood Scenarios 5- / 30-yearly 5- / 30-yearly 5- / 30-yearly event event event Predefined for the workshop Area Expected damages: - Personal damages - Material damages - Economic losses To be discussed in the workshop Risk Risk per year [USD] Calculated by software Implementation Measures for risk reduction To be discussed in the workshop Urban Flood Risk Management, September 18/19, 2014 7
Case Study: Risk Assessment (iii) Risk assessment for different situations Current situation Future situation Future situation 1 after implementing of a «measure package 1» Future situation X after implementing of a «measure package X» Future situation 2030 without implementing of any measures Urban Flood Risk Management, September 18/19, 2014 8
Case Studies: Action Strategies, Measures Avoid No settlements in flood prone areas Resettlement Limit Maintenance (river, drainage system, forest) River revitalisation (more space) Building appropriately (above natural terrain) Planning of retention areas Reduce of impervious surface Contain Maintenance (river, drainage system, forest) Technical measures Object protection measures Forecast system Urban Flood Risk Management, September 18/19, 2014 9
IT Tool RiskPlan (i) RiskPlan is a calculation and management tool to assess and monetize the risks posed by hazards in defined areas and to evaluate the cost-effectiveness of (protective )measures enables a pragmatic and participative approach to risk management is an excellent instrument for the risk dialogue Urban Flood Risk Management, September 18/19, 2014 10
Content of Case Studies Working Groups Session 1(Thursday afternoon, 15.00 17.30) Analysis of current situation, challenges, risks Analysis of future situation 2030 without measures Session 2 (Friday morning, 9.30 13.00) Future approaches, concepts, strategies, measures Analysis of future situations after implementation of measures Session 3 (Friday afternoon, 14.00 15.00) Summary of findings and preparation of presentation Urban Flood Risk Management, September 18/19, 2014 11
Working Groups - Grouping Manila (room: Quadro) Barranquilla (room: Grande 1) Ba Ria City (room: Grande 2) Dolores M. Hipolito Carlos Acosta Do Anh Tuan Lea Rüfenacht Hoang Thi Minh Trang Jürg Elsener Andreas Zysset Christian Willi Niels Holthausen Lilian Blaser Peter Locher Matthias Ulmer Matthias Gerth Jürg Mannes Hans-Jakob Bösch Thomas Espinosa Rao Fu Robert Scherzinger Fabiana Henke Sonja Stocker Natalia de Faria Gerd van den Daele Participants from SECO, ZURICH and SWISS RE: no fixed group Urban Flood Risk Management, September 18/19, 2014 12
Working Groups Basics (i) Urban Flood Risk Management, September 18/19, 2014 13
Working Groups Basics (ii) Ba Ria City, Vietnam Barranquilla, Colombia Manila, Philippines Urban Flood Risk Management, September 18/19, 2014 14
Thank you!