Urban Flood & Climate Change ----information from APWMF and SIWW

1. Urban Flood & Climate Change ----information from APWMF and SIWW Jinping LIU Hydrologist Typhoon Committee Secretariat

2. The Asia-Pacific Water Minister’s Forum (APWMF) June 28, 2010 • Jointly organized by MEWR and PUB of Singapore , and in cooperation with APWF. • Attended by Ministers and water leaders from 15 countries. • Themed ‘Water Security—Good Governance and Sustainable Solutions’. • Articulated the region’s water issues, policies and solutions.

3. Singapore International Water Week (SIWW) June 28 ~July 1, 2010. • Inaugurated with 2nd World Cities Summit (WCS). • Themed ‘Sustainable Cities: Clean and Affordable Water’ for SIWW. • Themed ‘ Liveable & Sustainable Cities for the future’ for WCS. Around 10,000 participants from more than 100 countries and regions.

5. Today’s presentation • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change

6. Urban/rural population for less and more developed region

7. Urbanization - Tsurumi River Basin 1958 Urbanization Rate Population increased by 1.7 million in 40 years. 85% of the river basin urbanized. It has become a typical urban river. 1975 1975 1995 1995 Natural Urban

8. Influence of Urbanization on Flood Risk

9. Rainfall pattern is changed. Heavy rainfall in a city of Japan (1990~1999) Annual Precipitation in Macao in the period of 1901~2008

10. Hydrological response is changed. • Less infiltration • More runoff • Higher velocity • Shorter travel time • Higher peak flows • More frequent channel forming flow • Lower low flows • = Extremes

11. Flow Increase & Time of concentration Decrease Present 70 mm/hr Intensity mm/hr frequency 1:50 yr Past 1:10 yr Discharge 20 60 duration Time

12. Today’s presentation • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change

13. Heavy Precipitation Events: Frequency increases over most areas Anomalies (%) of the global annual time series defined as the percentage change of contributions of very wet days from the base period average. Kobe, Japan 2008 (Prof. Toshio Koike, The University of Tokyo ) IPCC AR4

14. IPCC AR4 Projected changes in extremes: It is very likelythat heavy precipitation events will continue to become more frequent. > 90%

15. Recent trends, assessment of human influence on the trend and projections for extreme weather events for which there is an observed late-20th century trend.

16. Ratio of Daily 10year Probable Rainfall between 50 years later according to A1B and the current, from 17 models Average=1.2 (from 17 models) Araki & Koike, 2008

17. Design Rainfall Design Hydrograph Current Design Rainfall Future Design Rainfall under Climate Change Discharge (m^3/s) 1 1.2 Climate Change Hydrological Model Current Climate T

18. Design Flood Control Current Design Future Design under Climate Change 1:150 Uncertainty Future under climate change Target Flood safety level 1:150 Basin wide measures 1:80 Current Flood safety level 1:80

19. Climate Change Impacts on Flood Control Planin Indonesia 10year Probable flood 50 years later 10year Probable floodCurrent Climate

20. Today’s presentation • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change • Urbanization Affecting Flood Risk • Climate Changes Affecting Flood Risk • Approaches: Adapting to Climate Change

21. In responding to Climate Change, investment for prevention under uncertain targets is extremely difficult, especially for developing countries. • The best option is to take an adaptive approach that build climate resilience into development strategies. • Adapting to What? • As the future is unknown, adaptation should be flexible, incremental and capable of incorporating changes based on new knowledge. • It should be a continuous process guided by sustainability concerns and address multiple needs.

22. End to End Approach on Climate Change Adaptation Socio-economical approach Scientific approach Engineering Approach Climate models Flood Disaster potential Adaptation options Quantifying uncertainty Current facility, plan, management Water quantity and quality prediction Early warning Human Behavior Water allocation & cost Impact assessment Environ-ment Information Decision making implementation • Innovative technology • Flood control • quality control Multi-model ensemble (MME) flood Process Study Flood control system ordinary water Filed survey Human life Down-scaling ground water Economic Behavior Storage Integrated Observed Data Sets Industry Allocation policy drought Treatment Basin-scale prediction of quantity & quality Monitoring evaluation Drought Disaster potential Land use etc. (Prof. Toshio Koike, The University of Tokyo )

23. CLIMATE PROOF ROTTERDAM .... CLIMATE PROOF ROTTERDAM 2025 Action Implement Road map Monitoring Assessment Accessiblity City Climate Flood Management Adaptive Building Urban Water System knowledge CLIMATE PROOF Rotterdam 2009 Rotterdam Climate Adaptation Strategy 1.0 Arnoud Molenaar

24. Concluding Remarks • Climate Change, Urbanization and Urban migration are the greatest challenges for urban flood disaster risk reduction. • Flexible adaptive measures - adaptive adaptation - should be mainstreamed. Innovative holistic approaches based on risk assessment are needed to achieve this. • Urban flood is not isolate issue. UFRM should be integrated with holistic urban system. • Urban flood is a kind of resources. UFRM is not to simply discharge flood out side of city, but to promote the beneficial and abolish the harmful.

25. “The Shapers of New Asia” “They include YOU and ME….” Thanks