1/38 Urban Flood & Climate Change ----information from APWMF and SIWW Jinping LIU Hydrologist Typhoon Committee Secretariat

2/38 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.

3/38 Singapore International Water Week (SIWW) June 28 ~July 1,  Inaugurated with 2 nd 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.

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5/38  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 Today’s presentation

6/38 Urban/rural population for less and more developed region

7/38 Urbanization - Tsurumi River Basin Population increased by 1.7 million in 40 years. 85% of the river basin urbanized. It has become a typical urban river Urbanization Rate Natural Urban

8/38 Influence of Urbanization on Flood Risk

9/38 Rainfall pattern is changed. Annual Precipitation in Macao in the period of 1901~2008 Heavy rainfall in a city of Japan (1990~1999)

10/38 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

11/38 Flow Increase & Time of concentration Decrease Present Past Time Discharge Intensity mm/hr duration 1:10 yr 1:50 yr 2060 frequency 70 mm/hr

12/38  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 Today’s presentation

13/38 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 IPCC AR4 (Prof. Toshio Koike, The University of Tokyo )

14/38 It is very likely that heavy precipitation events will continue to become more frequent. IPCC AR4 > 90% Projected changes in extremes:

15/38 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.

16/38 Araki & Koike, 2008 Average=1.2 (from 17 models) Ratio of Daily 10year Probable Rainfall between 50 years later according to A1B and the current, from 17 models

17/38 Discharge (m^3/s) T Current Design Rainfall Future Design Rainfall under Climate Change Design Hydrograph Design Rainfall Hydrological Model Current Climate Climate Change

18/38 Current Flood safety level Target Flood safety level Uncertainty Basin wide measures 1:80 1:150 1:80 1:150 Future under climate change Current Design Future Design under Climate Change Design Flood Control

19/38 Climate Change Impacts on Flood Control Plan in Indonesia 10year Probable flood Current Climate 10year Probable flood 50 years later

20/38  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 Today’s presentation

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.

22/38 Quantifying uncertainty Climate models Multi-model ensemble (MME) Down-scaling Basin-scale prediction of quantity & quality Water quantity and quality prediction flood ordinary water drought ground water Information Storage Treatment Current facility, plan, management Flood control system Water allocation & cost Environ-ment Human life Industry Human Behavior Economic Behavior Drought Disaster potential Flood Disaster potential Impact assessment Filed survey Early warning Allocation policy Land use Adaptation options etc. Innovative technology - Flood control - quality control Decision making Monitoring evaluation implementation End to End Approach on Climate Change Adaptation Integrated Observed Data Sets Process Study Scientific approach Engineering Approach Socio-economical approach (Prof. Toshio Koike, The University of Tokyo )

23/38 Rotterdam Climate Adaptation Strategy 1.0 Adaptive BuildingAccessiblity Urban Water System City ClimateFlood Management CLIMATE PROOF Rotterdam 2009 CLIMATE PROOF ROTTERDAM 2025 CLIMATE PROOF ROTTERDAM.... Monitoring Action Assessment Implement Road map knowledge Arnoud Molenaar

24/38 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.

25/38 Thanks “The Shapers of New Asia” “They include YOU and ME….”