urban flood risk management for the 21st century · urban flood risk management for the 21st...
TRANSCRIPT
![Page 1: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/1.jpg)
Urban Flood Risk Management for the 21st Century
Global Disaster Platform 2011Geneva, May 12, 2011
Abhas Jha,
Program Leader,
Disaster Risk Management,
East Asia and Pacific,
World Bank
![Page 2: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/2.jpg)
March 11, 2011
Prevention pays but be prepared for the unexpected.
![Page 3: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/3.jpg)
Three Questions
1. Is urban flooding on the rise globally?
2. If so, what are the factors driving the increase?
3. And, what can city-managers, policy-makers do about it?
![Page 4: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/4.jpg)
Three Products
1. Expert Roundtable on Urban Flooding (March 17): Presentations can be downloaded here: http://bit.ly/lLej8X
2. Working Paper on Cities and Flooding: http://bit.ly/lbxm0x
3. Handbook on Integrated Flood Risk Management
![Page 5: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/5.jpg)
Why Are We Doing This?
1. Urban flooding a serious and growing problem.
2. Multi-disciplinary-hydrology, land-use planning, risk assessment, risk financing and insurance.
3. Need to document several decades of project/AAA experience.
![Page 6: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/6.jpg)
1. Is urban flooding on the rise globally?
![Page 7: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/7.jpg)
Are the impacts of global urban flooding on the rise?World Bank Working Paper Summary
• Urban flooding is an increasingly important issue.– Brisbane, Rio, Ha Noi, HCM City,
Ulaanbataar, Dakar, Mumbai etc. etc.
• The impact of flooding is driven by a combination of natural and man-made factors.
• Two headlines:• Urbanization• Climate change
![Page 8: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/8.jpg)
• Flood events are becoming more frequent.
• Larger growth in medium and small floods.
• Deaths lower, particularly in the developed world.
• Other impacts from flooding are growing more steadily over time.
0
50
100
150
200
250
19
50
19
53
19
56
19
59
19
62
19
65
19
68
19
71
19
74
19
77
19
80
19
83
19
86
19
89
19
92
19
95
19
98
20
01
20
04
20
07
20
10
Events 10 year moving median
Number of reported flood events
![Page 9: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/9.jpg)
2. What are the factors driving the increase?
![Page 10: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/10.jpg)
Increased Vulnerability
– Population growth– Economic development– Urbanization– Poverty– Lack of preparedness– Changing demographics of populations– Poor maintenance of existing structures and
makeshift construction– Building design without regard to flood risk– Overcrowding leading to increased solid waste
and flood debris– Overreliance on defences
![Page 11: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/11.jpg)
Climate Change and DRM
• Humans are affecting climate
• Models are predicting significant warming (Global Mean Temperature)
• Models are predicting sea level rise (magnitude and timing considerably uncertain)
• Models are predicting slight drop overall hurricanes but a higher percent of Cat 4 and 5.D
ecre
asin
g C
onfidence
Source: Tom Knutson, Geophysical Fluid Dynamics Lab/NOAA
![Page 12: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/12.jpg)
Stationarity is Dead!
• Decision making under deep uncertainty
• Resilience and Robustness
• Complexity and Cascading Failures
• NIMTOF
![Page 13: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/13.jpg)
Urban PopulationPercent
29
15 17
53
47
37 37
76
55
42
74
85
54
61
82
World Africa Asia Latin America
and the
Caribbean
More
Developed
Regions
1950 2000 2030
Source: United Nations, World Urbanization Prospects: The 2003 Revision (medium scenario), 2004.
Trends in Urbanization, by Region
![Page 14: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/14.jpg)
3. What can city-managers, policy-makers do about it?
![Page 15: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/15.jpg)
Measures to reduce flood risk
> 185 adaptation measures identified…..
• SAMs: Structural (hard) measures (# >100)
• Collective: e.g. dikes, drainage systems
• Individual: e.g. wet or dry proofing
• NSAMs: Non-structural (soft) measures (# > 85)
• Collective: e.g. contingency plans, legislation
• Individual: e.g. risk consciousness, insurance
… and counting
Source: Deltares
![Page 16: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/16.jpg)
Threshold capacity
Coping capacity
Recovery capacity
Adaptive capacity
recurrence time
Strategy to reduce/manage vulnerability
* Graaf, R. de, N. van de Giesen and F. van de Ven, 2007, Alternative water management
options to reduce vulnerability for climate change in the Netherlands, Natural Hazards nov.
Strengthen four capacities* to reduce vulnerability
Source: Deltares
![Page 17: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/17.jpg)
Vulnerability reduction approach
• Strengthen all four capacities
• SAMs show limited adaptability
• Most SAMs strengthen threshold & coping capacity
• SAMs require high federal or regional investments
• NSAMs require less, local or individual investments
• NSAMs require study (learning) and regular training
• SAMs can’t do without NSAMs
![Page 18: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/18.jpg)
Dealing with Uncertainty in Decision Making
• In many cases a range of ‘no-regrets’ options are available and will have immediate benefits and can enhance long-term flexibility to cope with climate change and other risk drivers;
• Measures to better cope with current climate variability (such as well-maintained drainage systems and early warning systems)
• Measures to manage non-climate drivers of risk (such as limiting building in exposed areas, managing erosion and increasing
• permeability of urban areas)
• Measures to reduce systemic vulnerability or resilience to shocks (insurance systems, emergency response planning)
• Some measures with strong co-benefits (such as natural ecosystem flood storage systems, regenerating mangrove areas,green urban spaces)
![Page 19: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/19.jpg)
Source: Ranger and Garbett-Shiels, 2011, LSE
![Page 20: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/20.jpg)
Integrated Flood Risk Management
Good Metrics for Evaluating CB Between Structural and Non-Structural Measures
![Page 21: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/21.jpg)
Key Challenges
• So what’s new?
• Multiple audiences
• Operational and policy relevance
• Typology of cities (coastal vs. non-coastal, small vs. medium vs. large)
![Page 22: Urban Flood Risk Management for the 21st Century · Urban Flood Risk Management for the 21st Century Global Disaster Platform 2011 Geneva, May 12, 2011 Abhas Jha, Program Leader,](https://reader035.vdocuments.us/reader035/viewer/2022062908/5add40af7f8b9a4a268d4c79/html5/thumbnails/22.jpg)
Timeline
1. Regional consultations- May-June
2. Case studies (Good or bad practice)-by May 2011.
3. Comments on draft chapters-May-June 2011.
4. Suggestions on dissemination-July 2011.