Vegetation Canopies - a New Approach to Urban Flood Mitigation - Dato' Ahmad Fuad Embi
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Vegetation Canopies – a New Approach to Urban Flood Mitigation Dato’ Ahmad Fuad Embi
CONTENTS
1.Background of KL Flooding
2.Hard Engineering - Dams and channelization
3.SMART Tunnel and Ponds
4. Soft Approach – Vegetation Canopies
Rehab for catchment
KL FLOOD 1911
Sultan Abd Samad Bldg
KL FLOOD 1971 Central Market
Sg Klang and its Tributaries
Raised by 10 ft and Gates
built over spillways
Klang Gates Dam
Flood Control works 1979
Batu Dam
completed 1984
Primary function: flood control
TEPU BINA 1988 KLANG VALLEY URBANISATION 1984
TEPU BINA 1994 KLANG VALLEY URBANISATION 1994
TEPU BINA 1998 KLANG VALLEY URBANISATION 2004
SUBANG JAYA A dense housing suburb with conventional ‘rapid disposal’ drainage, and large areas of impermeable surface Runoff from storms rapidly reaches main drains in minutes.
Typical concrete-lined main drain from old housing area –
rapid disposal of stormwater to riverGrowth of Elevated Highways to ease traffic congestion – increasing rapid runoff to river
RIVER CHANNELIZATION
• Started as solution to flooding problem
after major flood in 1971
•‘Rapid disposal’ concept – increase capacity
and quickly dispose of flood waters.
MASJID JAMEKConcrete lined channels throughout KL – 1970s, 80s, 90s Very high cost, single objective
Light Rapid Transit (LRT) lines 1990s - occupying river berms, retarding high flows
BUT.. Klang River (& tributaries) continued to
flash-flood, and with increasing frequency
SRI MUDA, KLANG 1998MEAN ANNUAL FLOOD ANALYSIS for SG.
KLANG – shows alarming trend
3116430 KLANG RIVER AT SULAIMAN BRIDGE
TEST FOR STATIONARITY OF SERIES OF ANNUAL MAXIMUM DISCHARGES
16,000
CUMULATIVE MASS OF ANNUAL MAXIMUM DISCHARGE
14,000
12,000
Mean annual flood: Sg. Klang
@Jamb. Sulaiman shows huge
10,000 increase
148 → 440 cumecs (3X)
(m3/s)
8,000
6,000
Mean annual flood = 440 m3/s
4,000
Mean annual flood = 148
2,000
m3/s
0
1910 1915 1920 1925 1930 1935 1940 1952 1957 1963 1968 1974 1979 1986 1991 1996
YEARSMART (Stormwater Mgt
and Road Tunnel)
proposed as structural
solution 1998
• cost 1.6 Billion Ringgit
• privatised road tunnel
3 km in middle
• stormwater tunnel length
10 km
• expected usage 2 – 5
times a year
• one of the largest
tunnels in world
• completion end 2006
• supplemented by Batu
Pond diversionSMART
TBM No.1 – SOUTH DRIVE Tunnel Boring Machine break-through, June 2005
BATU & JINJANG DETENTION PONDS
( RM 600 M project)
80 cumec 290 cumec
150 cumec
Lencongan Gombak (3.375 km) 275 cumec
Kolam
Takungan Kolam Takungan
Jinjang Batu
(2.5 mcm) (4.5 mcm)
100 cumec
125 cumec 35 cumec 35 cumec
Kolam Kg
Puah
65 cumec
Kolam Kg
Benteng
(0.4 mcm)
PWTC
Masjid Jamek
350 cumecSG. BATU FLOOD DETENTION POND
NEW PROBLEM: NEED FOR FUTURE
RETROFITTING TO REVIVE URBAN RIVERS
•30 years of extensive concrete lining
•Monotonous uniformity bad for habitat – no bends, loops,
meanders, pools, rapids, esp. greenery
•No gravels or stones on riverbed for egg-laying
•No rocks or tree stumps for fish shelter.MANAGING URBAN STORMWATER
• Air quality much improved –
exhaust from millions of vehicles .
• Decrease noise levels
• Cools air temp. & UHI effects
• Soil better protected.
• Better habitat & biodiversity.
• More CO² absorbed from the air in
the city.
• Can reduce up to 40% of urban
flash floods
• Rehab catchment NOT introduce
more Hard Engineering
• Malaysia’s commitment to Climate
Change Accord
Vegetation Canopy
- Benefits• 15 to 30 different species of trees and
Miyawaki shrubs planted together.
• has structure of a mature natural forest.
urban forests • Is a multi-storey structure, with different
levels of vegetation.
• Such Forest has many benefits in
ecosystem services.Grows min. of 1 m /yr without fertilizers. 200 years for forest to recover on its own. Miyawaki method: 20 years.
2000 world-
wide
Miyawaki
projectsKL Low density vegetation, few bushes Grass cut too short, thin topsoil , exposed Rapid and high runoff – Frequent flash floods
UN Decade on Ecosystem Restoration (2021-2030) Trees and forests are a critical part of the solution to the climate crisis and biodiversity collapse. The World Economic Forum mobilize global community to grow one trillion trees by 2030. nature-based solutions in support 1t.org conservation, restoration and reforestation
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