Taisuke Watanabe, Japan International Cooperation Agency - Urban flood control: the case of the Philippines

1. Toward Disaster & Climate Resilient,Toward Disaster & Climate Resilient,
Sustainable CitiesSustainable Cities
─ Urban Flood Control and related tools── Urban Flood Control and related tools─
Taisuke WatanabeTaisuke Watanabe
Japan International Cooperation AgencyJapan International Cooperation Agency
17 February 2015 @OECD Environet17 February 2015 @OECD Environet
Watanabe.Taisuke@jica.gop.jpWatanabe.Taisuke@jica.gop.jp
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2. Presentation Outline
- Low priority on disaster risk reduction (DRR)
while increasing vulnerability
→Mainstreaming DRR
- Flood Control Measures in Manila
→Gap bet. DRR and Climate Change
- Tools
Win-Win
Land use
Eco-DRR
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3. Increased vulnerability to Flood Risks in Urban Areas
- Major Adaptation Challenge for Asian cities
Increased vulnerability to
Flood Risks in Urban Areas
Heavy Rainfall Events
Rise in Groundwater Level
Multiple factors Related to Rapid
Urbanization
-More & faster water run-off
-Habitation in high risk zones
-Lack of measures
Adaptation measures
Structural Measures
Construction of Dikes, Improvement of
Drainage, etc.
Non-Structural Measures
-Risk Mitigation Measures at
Household/Community Levels
-Early Warning and Evacuation System
Appropriate City Planning
Environmental Management
-Sewage System
-Waste and Sanitary Management
Necessity of a ‘Long-term Resilient City
Development Plan’
Necessity of a ‘Long-term Resilient City
Development Plan’

4. There are many options for action.
Philippine National Climate Change Action
Plan says;
Adopt flood plain management and flood hazard
reduction by establishing flood plain zones and new
operating rules during flood periods as modular or
incremental adaptation measure.
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Actions in National Climate Change Plan

5. Urban Flood Control in Manila
Structural measures
- Mangahan Floodway
- Pasig-Marikina River Channel Improvement & others
- Observation and Operation System
Non-Structural measures
- Forecasting & Early Warning
Capacity Building
- National Gov and Local Gov
- Training, Guidelines
- Planning works

6. Manila: Pasig-Marikina River Basin
Mangahan
Floodway
Phase &Ⅱ Ⅲ PhaseⅢ
PhaseⅣ Rosario
Weir
Pasig-Marikina River Channel Improvement

7. 7
・ O:Original PhaseIV Component
・ A:A+Hightenning Levee +Mangahan
Floodway Improvement
・ B:A+NRB+Additional Capacity
・ NRB
+Additional Capacity
・ Dam+NRB
・ Dam
・ Dam+FCB
NRB: Natural Retarding Basin
FCB : Flood Control Basin
Adaptation Measures for Climate Change
Step Up Options of Adaptation Measures for Climate Change
・ Climate Change
Adaptation Measures
Options
• Preparing options based on existing plans and
IPCC data

8. 8
New Dam
Construction
Securing of
NRB/FCB Volume
Underground
Floodway
Underground
Storage Facility
（ Tunnel
Storage ）
Runoff Control
Facilities
Estuary - MCGS MCGS-Sto.Nino
Dam flood control function
Improvement
Sto.Nino
MF Capacity
Improvement （ Securing
of cross-sectional area or
Laguna Lake level lowering
Measure Upstream of Sto.Nino
NRB/FCB flood control
function Improvement

9. Win-Win setting by incorporating DRR component
Implementing Projects with DRR elements in Various Sectors
Thailand ： Flood Resilient
Subway
Philippines: Typhoon
Resistant HospitalThailand: Raised Road
Raised 1m for
flood
mitigation
– Road Raising for Flood Mitigation
– Typhoon Resistant Hospital
– School-cum-Evacuation Center
– Flood Resilient Subway System
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10. Land Use: Setting River Boundary
Flood Risk Management Project for Cagayan de Oro River
Inundation Analysis/
Inundation Risk
Assessment
Delineation of River
Boundary/
Formulation of M/P
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JICA supported the Philippines on;
•Assessment of local evacuation capacity
•Inundation analysis and risk assessment
•Updating flood master plan
JICA supported the Philippines on;
•Assessment of local evacuation capacity
•Inundation analysis and risk assessment
•Updating flood master plan

11. Land Use: Reconstruction planning after Haiyan
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Political commitment on Typoon Yolanda (Haiyan):
The government of Philippines sets “Build Back Better” as a basic concept
for recovery and reconstruction by using the disaster as a trigger to realize
disaster resilient societies.
Political commitment on Typoon Yolanda (Haiyan):
The government of Philippines sets “Build Back Better” as a basic concept
for recovery and reconstruction by using the disaster as a trigger to realize
disaster resilient societies.

12. Concept for future Land Use Plan,
“build back better”
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No build zone
40m
Controlled zone
New Plan
RoadRaised
Seawall
×
SecondaryProtectionRoad
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13. 13
Sea wall
Secondary Protection Road
Controlled Zone
No Build Zone
Safe Zone

14. Project Scope was expanded
for rehabilitation from Cyclone
Nargis:
Damage & recovery survey
on the communities
New hazard map based on
the satellite images
CF extension & nursery
centers rehabilitated with
reinforcement
Recovery survey of
mangrove vegetation
Eco DRR Case : Myanmar- Cyclone Nargis
Integrated Mangrove Rehabilitation and Management through
Community Participation in the Ayeyawady Delta
Hazard
Map
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15. Build Back Better
by Rehabilitation of Mangrove Forests
JICA Grant Aid Assistance (2012-2017)
- Mangrove afforestation (1,154 ha) for enhancement of disaster reduction
effects of mangrove ecosystem, validated / reaffirmed
- including construction of a forest monitoring tower-cum-cyclone shelter /
enhancement of participatory risk reduction training
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Mangrove Reforestation
(Jul, 2009)
View of Mangrove Nursery
Bed Area (Jul, 2010)

16. Thank you!
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