2010/10/17 at Arizona State University
UGEC2010
Field-level adaptation to floods and sea level rise
in coastal peri-urban areas in monsoon Asia:
Comparative case studies between
continental Bangkok and insular Metro Manila
Yuji Hara1 & Danai Thaitakoo2
1: Wakayama University, Japan
2: Chulalongkorn University, Thailand
hara@sys.wakayama-u.ac.jp
Asian large cities (population > 5million);
Located on continental delta / insular lowlands
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Purpose of this presentation
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To show present case studies on landform
transformation (LT) in response to flooding in
continental Bangkok and insular Metro Manila
– Horizontal land-use changes
– LT processes
– LT and floods
– Field-level responses to floods (by local people
and government)
– Toward land-use and LT integrated planning for
minimizing a flood hazard
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Case study cities
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Continental Bangkok
Insular Metro Manila
Built-up area
0
Built-up area
100km 0
100km
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Horizontal land-use change:
From rice fields to townhouses
(Hara et al. 2005)
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Vertical LT process:
From dig & fill to introduced fill
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5m
Khlong
Material (texture, color)
Clay fill (CL, 5Y5/1)
Road
Sand fill (S, 10YR6/6)
0
Crushed rock
Concrete plank
Water body
Orchard
Apartments
Institution
Orchard
Orchard
Institution
Khlong Khlong
houses houses
Khlong Khlong
houses houses
1500m
Rice Townhouse Townhouse Wasteland
field
Rice field
Rice field
Fishpond
Townhouse
Townhouse
Vacant land Fish Rice field Fishpond Rice field
pond
Wasteland
2000 Land use
Soil pit
1987 Land use
-5m
1000m
300,000
Volume (m3/km2)
250,000
200,000
150,000
100,000
50,000
0
1952
1967
1979
Year
1987
1995
2002
(Hara et al. 2008a)
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Introduced fill from further areas (the rim of delta)
Fill volume (Hara et al. 2008a)
Production: 5.5×107 m3 year−1
Input: 5.7×103 m3 km−2 year−1
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Flood characteristics:
Sheet flow and parcel-level water management
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Water level of main stream of Chao Phraya River (at Nonthaburi monitoring sta.)
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1.5
1
0.5
0
2006/4/1
2006/5/1
2006/6/1
2006/7/1
2006/8/1
2006/9/1
2006/10/1
2006/11/1
2006/12/1
2007/1/1
2007/2/1
2007/3/1
2007/4/1
(using RID data)
Floods come gradually
 Water level is manageable
per each parcel using
private pump with
gasoline engine

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Temporal adaptation to sheet flow flooding
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Using sandbags to build
temporal banks to protect
water coming in, and then
releasing floodwater to the
canal by pumping
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Using a boat, that was
traditionally utilized as a
main transportation mode
and still kept along the
canal
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10 – 20 years adaptation to rising water baseline due UGEC2010
to the loss of flood retention capacity by introduced fill

Lifting up a pathway
and a road
 Lifting up a floor
(as their traditional house structure)
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Suggestions for spatial planning
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Main problem on the current planning process
– No linkage between land-use plan and water
management plan
 Toward better planning
– Zoning based on acceptable fill (water) volume
that can induce field-level adaptation using
inherent LT methods
– Focusing not only on regulative measures but
more on incentive ones (for instance bonus floor
area ratio for preparing ponds)
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Continental Bangkok
Insular Metro Manila
Built-up area
0
Built-up area
100km 0
100km
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Coastal Plain – Central Upland – Eastern Plain
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Horizontal land-use change:
From natural micro landform basis to LT basis
(Hara et al. 2008b)
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Vertical LT process: Landfilling on lower landforms
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Material (texture, color)
Clay fill (HC, 2.5Y3/3)
Sand fill (S, 5Y5/1)
P.Rosales Street
Crushed rock
Construction waste
(broken concrete etc.)
Water body
5m
0
-5m
Detached houses
Slum-type housing
Swamp
Detached houses
Slum-type housing
Rice field
Detached
houses
Forest
Slum-type housing Vegetable patch
Detached
houses
2004 Land use
Vegetable patch
Detached
houses
1986 Land use
Detached
houses
1966 Land use
Rice field
(Hara et al. 2008b)
500m
Volume (m3/km2)
400,000
350,000
Lacustrine delta &
Lacustrine plain
300,000
Lower lacustrine terrace
250,000
Upper lacustrine terrace
200,000
Natural levee
150,000
Back marsh & Valley plain
100,000
Upland
50,000
0
1966
1986
Year
2004
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Flood characteristics: Flash flow
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Eastern plain as “flood control pond” to protect downstream central Manila
(Hara et al. 2002)
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10 – 20 years adaptation: Individual landfilling
up to the highest flood level in their experiences
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Adapting themselves to their own experiences without any consideration of
neighbors and flood control scheme by the government
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It has caused changes in distribution of flood-prone
areas and required temporal adaptation
SPOT 1987/11/18
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SPOT 1997/10/26
Emerging submerged areas with poor drainage
surrounded by landfill corridor
(Hara et al. 2002)
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New threat due to infrastructural development
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Tropical
Storm
Ondoy
Flooded
Areas
(NAMRIA 2009)
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New infrastructures accelerated flash flow hazard
ALOS PALSAR image soon after Ondoy
(Modified after NAMRIA 2009)
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Newly built bridges trapped a lot
of debris, and functioned as
temporal dam during Ondoy
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Failure of planning: Subdivision out of lakeshore dike
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It was built before the
construction of
lakeshore dike in 2004
(not subject to zoning code?)
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Suggestions for spatial planning
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Main problem on the current planning process
– Land-use plan is based only on road network
 Toward better planning
– Landfill practice should be subject to micro
landform to avoid poor drainage area surrounded
by landfill corridor
– Need to coordinate landfill material flows
between suppliers and consumers
– Link between infrastructures (including non flood
protection ones) and land uses
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Summary matrix
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Bangkok
Metro Manila
Landform
• Continental delta
• Homogeneous flat plain
• Insular lowlands
• Visible micro landforms
Floods
• Sheet flow
• Flash flow
• Water level is manageable • Water level is
per each parcel using
unmanageable without
pumping
public infrastructures
LT methods • Dig and fill development
• Fill from further area
• Landfilling using
construction debris
Field-level • Temporal banks
adaptation • Changing transportation
• Individual fill on the floor
• Evacuation boat
• Lifting up pathway & floor • Staying upper floors
Similar case studies are being carried out in other Asian low-lying cities…
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