Action Plan Towards Effective Flood Hazard Mapping In Malaysia

I. THE ROLE OF FLOOD HAZARD MAPS TO MITIGATE FLOOD DAMAGE IN
MALAYSIA
A.1

Flood Status in Malaysia
Malaysia has along history of flooding, the country being exposed to monsoon winds
and heavy conventional rainfall all year round rendering more than about 10% of thecountry being flood-prone. The annual average rainfall is 2,420 mm for Peninsular
Malaysia, 2,630 mm for Sabah and 3,830 mm for Sarawak, with heavier
precipitation recorded in the east coast of Peninsular Malaysia and the coastal
regions of Sabah and Sarawak.
In the rural areas where farming is the main economic activity, the rainy season andseasonal flooding is in fact good for paddy cultivation. However, the occurrence offlood hazards in urban areas, especially flash floods, is considered a sign ofunsustainable development. This is largely due to the rapid development of urban
floodplains such as those in Kuala Lumpur, Penang and Sarawak.
The replacement of natural forest with impervious urban areas results in almost all
the rainfall entering the rivers in a time. This reduces the capacities of most rivers todrain away excess water. Rivers in urban areas are very constricted and development
literally comes to the rivers banks. There is no buffer zone or river reserve leaving
no room to maneuvers. Hence, reducing their drainage capacities.
Rapid urbanization of urban floodplains and upstream development of hill land havechanged surface characteristics and altered the hydrological cycle, particularly thetime in which rains drops enter the rivers and the volume of runoff.
Hill and land development is a form of unsustainable development which often
results in accelerated soil erosion and landslides, two forms of environmental
hazards. Soil erosion leads to sedimentation and siltation of rivers, contributing toincreasing floods hazards of more severe magnitudes.

A.2

Present Countermeasures for Mitigating Flood Damages in Malaysia
From the studies that have been carried out, various structural (curative) as well
as non-structural (preventive) measures have been proposed to alleviate floodproblems.

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Structural measures are actually engineering methods which include thefollowing:i)Multi Purposes Dams.
The construction of multi purposes dams has been most popular. Dams have been
known to be effective as in the case of Linggiu Dam in Johore, which has
effectively reduced much of the flooding downstream of Sungai Johor. TheLinggiu Dam is an example of a dam built for water supply but also as a flood
mitigation dam.
However, dams are expensive and cause a great deal of environmental problems.
They also have a life span and pose serious dangers to downstream population,
both humans and others.
ii)
Bunding of Rivers
The construction of bunds is used to control bank erosion. River meanders
exposed to severe erosion are protected by the construction of wall of earth or
cement/concrete walls. This reduces rate of river bank erosion which contributetowards siltation and the reduced discharge capacities of rivers.
iii)
River Improvement
River improvement involving regularly dredging and deepening major river
channels, preventing the dumping of rubbish into the rivers and clearing of
rubbish and other obstacles such as tree trunks, boxes and oil drums in the rivers
to ensure smooth and swift flow. This includes channel deepening, widening andstraightening.
iv)
Retention Ponds
Retention ponds are commonly constructed along flooded rivers as low lying
areas along rivers can be easily converted into retention ponds which siphon
excess discharge during high flows, thus reducing the probability of floods.
During normal times, the retention ponds can be used as playing fields ormaintained as scenic shallow lakes which contribute to the aesthetic aspects ofriver corridors.
v)
Canalisation And Related Works
Canalisation works include the widening and deepening of channels as well as
lining the banks and beds of the channels. They also include the replacement ofConcluding Report
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Action Plan Towards Effective Flood Hazard Mapping In Malaysia

undersized structures such as bridges. These works are necessary, as the original
channels have become undersized as a result of the increase in flood flows caused
by development.
vi)
Flood Diversion Channel Or Tunnel
Certain river stretches especially in major city centers, due to intensive
development along both riverbanks can no longer be widened or deepened toaccommodate the increasing flood discharges through the city. Under suchcircumstances, excess flood water has to be retained upstream in storage ponds ordiverted downstream through a flood diversion channel or tunnel. This is being
implemented in Kuala Lumpur where the Storm water Management and Road
Tunnel (SMART) Project has become a viable and innovative solution. The SMART
system, when completed, will alleviate flooding in the Kuala Lumpur city centre by
diverting large volumes of flood water from entering the city centre. The tunnel isdesigned to incorporate a stormwater channel and a motorway for dual purposes(Figure 1)

Figure 1: Stromwater Management and Road Tunnel
Non-structural measures, on the other hand, are proposed where engineering
measures are not applicable or viable, or where supplemental measures arerequired. These measures comprise the following:i)Integrated River Basin Management ( IRBM )Under the concept of Integrated River Basin Management, the whole river basin isplanned in an integrated manner and all factors are taken into consideration when acertain development plan is proposed. Factors like zoning for river corridors, riparian
areas, natural flood plain, conservation of wetlands, storage ponds etc will be taken

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into consideration when preparing flood management plans. The concept of IRBM has
been incorporated into and will be implemented starting in the 8th Malaysia Plan.
ii)
Preparation of Guidelines and Design Standards
Suitable guidelines and design standards have been prepared, specifying clear
requirements, physical as well as technical, for rivers and their reserves, as well as
flood mitigation and urban drainage projects. These guidelines and design standards
if followed strictly by the public and private sectors will help to minimise theoccurrence of floods.
Recently in the year 2000, a new Urban Stormwater Management Manual (MASMA)
has been published by DID. The Manual provides control-at-source measures andrecommendations on flood fighting by utilising detention/retention, infiltration andpurification processes.
iii)
Resettlement of Population
One positive measure to reduce damage potential as well as loss of life in flood-prone
areas where floods would not be significantly reduced by structural measures is toresettle the population. Since 1971, 1672 families and 2715 families have been
resettled in the States of Kelantan and Pahang respectively.
iv)
Flood ProofingThis measure consists of implementation of protective works to prevent the entry offlood water into individual houses and specific places, for example, by bunding abuilding with a wall so that the floor is not submerged during a flood thereby reducing
flood damage. In flood-prone cities like Kuala Lumpur and Penang, entrances tobasement car parks should incorporate some flood proofing measures.
v)
Flood Forecasting and Warning SystemThe provision of a flood forecasting and warning system is an important, practical andlow-cost measure to minimise flood losses. Flood forecasts given early will enablepeople living in flood-prone areas to be warned so that they can evacuate themselves
and their belongings before the arrival of the flood. This can considerably reduce
flood loss and damage and above all the loss of human lives. In recent years, aweb-based information system on flood warning and flood information can be readily
obtained through website.

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A.3

The Usefulness of Flood Hazard Map in Malaysia
The Flood Hazard Map is a map that graphically provides information on inundation(predicted inundation areas, inundation depth, etc.), as well as on evacuation(location of evacuation refuges, evacuation routes, dangerous spots on evacuationroutes, etc.) in an easy-to-understand format.
The goal is to quickly evacuate local residents in a safe and proper manner in theevent of floods and reducing the loss of life as well as cost of damages. It does notmean by having flood hazard maps can stop a disastrous phenomenon. But theeffective use of flood hazard maps can decrease the magnitude disasters.

II. ALLOCATION OF ROLES IN MAKING FLOOD HAZARD MAPS IN MALAYSIA
B.1

Main Organization to Develop and Disseminate the Flood Hazard Map
It suggested, the main organization to be responsible for creating and provide theflood hazard map should from Ministry of Natural Resources and Environmental
collaboration between Ministry of Local Housing and State Government. Under theMinistry of Natural Resources and Environmental, there are relevant Departmentwhich has a capabilities and expertise to provide necessary information in process ofcreating and preparing flood hazard map.
The map is produced and publicized through a joint effort by those in charge ofdisaster prevention and those in charge of rivers and hydrology in the respective local
municipalities.
The roles of every ministry/department towards providing information and preparingof flood hazard map in Malaysia are as follow:
No

Department/Ministry

Roles

1.0

Ministry of Finance

To provide and approved theallocation for implementing, developand disseminating flood hazard map

2.0

Ministry of Natural Resources As a lead ministry to implementing
and Environmental
the Flood Hazard Map in Malaysia

2.aDepartment of Survey
Mapping, Malaysia.

and - To provide topographical, cadastral,thematic and utility maps for thepurposes of planning, management anddevelopment of flood hazard map.

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No

Department/MinistryRoles

2.b

National Hydraulic Research - To provide and conduct both basic
Institute of Malaysia
and applied research in hydraulicengineering and water resources
development for development of floodhazard map.

2.c

Malaysia Meteorological Agency Providing
weather
forecast
information due to flood forecasting
and warning activities.

2.d

Department of Irrigation and - Main departments for planning,
Drainagepreparing and disseminating FHM.

2.e

Malaysian Center For RemoteSensing (MACRES)- Providing the satellite images due toflood forecasting and warning
activities.

3.0- State Government- Ministry of Local Housing- Ministry of Education- Ministry of Information- Ministry of Internal Affairs

To Support and provide development
allocation for flood mitigation projects
at the state level.
Dissemination of Flood Hazard Map
Provide information on evacuationroutes in their region.

III. THE “ACTION PLAN” OF MAKING FLOOD HAZARD MAPS IN MALAYSIA
C.1Target River Basin
Sg. Damansara Catchments is located west of Kuala Lumpur and has an area ofabout 148 sq. km. Development within the catchments has been on going overthe years. The development has been gradual with areas in the fringes of Kuala
Lumpur such as Damansara, Taman Tun Ismail being developed about 30 to 40
years ago. Subsequently Shah Alam was developed as the capital of Selangor
replacing Kuala Lumpur as the latter became part of Federal Territory. Sg.
Damansara catchment is now estimated to have a population of about 226,000 in
the year 2000. The area contains important industries and areas of commercial
and economic significance to the state.
Sg. Damansara and its tributaries have no major river regulating structures such as dams
or barrages. Most of the river stretches passing urban areas however have been canalized

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and straightened (Figure 2)

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KayuAraSg Payong
SgRumputrasaan

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Sg

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Sg RumpututmluPeSgPelampasspalamPeSglbum
TaSgKayu

Sg

Sg Rumput

Sg Payong

Sg PakuAra

The government has made various efforts from time to time to mitigate the floodproblems. Sg. Damansara and its tributaries were deepened, widened, straightened andthereafter occasionally de-silted. Bunds were constructed at river banks to protect
adjacent populated low laying areas such as Kg. Kebun Bunga and Taman TTDI Jaya.
Pump stations were added to pump accumulated storm runoff from these areas. Withouta master plan and with limited budget, most of the flood mitigation works were carriedout in an ad-hoc manner. Flood waters inundated low laying areas comprisingresidential, commercial and institutional areas.

yuKaSgSg
Damansaragnin
Kua
Ar

AirFigure 2 : Sg. Damansara River System

Figure 3: Flooding in Taman TTDI Jaya on February 2006

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The most recent severe flood occurred on 26th February 2006. Two hours ofheavy rain of around 118 mm had resulted in Sungai Damansara overflowing its
banks and inundated about 3,000 houses and forced about 11,000 people tovacate the flooded areas (Figure 3).
C.2

The Usefulness of Flood Hazard Map in Sungai Damansara River Basin
The usefulness of Flood Hazard Map in Sungai Damansara River Basin is asfollows:i.
Provide the residents with information on the range of possible damage andthe disaster prevention activities;ii.
Use as the basic materials that the administrative agencies utilize to provide
disaster prevention service;iii.
As a tools to establish a warning system and the evacuation system;iv.
As a planning purposes, to inform decisions regarding where to locate newdevelopments, andv.
Technical support to the Director of State Security Department for issuing theevacuation order / recommendation order.
Data of flood event, inundation depth, aerial and satellite image are available inFlood Mitigation Division. The implementing and developing of Flood Hazard Map
at the target area will carry out in stages. And as a pilot project, the residential area
known as Taman TTDI Jaya have been identified to have its own flood hazard map.

C.3

Five Years Action PlanYearActionStatus

2006• Set up a non-structural unit.

Done• Provide training in developing flood inundation
map/FHM (internal/external).
• Identified the area for pioneer project.
2007

In ProgressDone• Create awareness to state government/others
agency on the important of Flood Hazard Map.
• Identify method to disseminate information
regarding flood hazard map to the public.
• Prepare and disseminate the completed FHM tothe target area.

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YearAction

Status• Provide training for local government on the useof flood hazard map.
2008

• Develop survey strategies to acquire information
about resident perception toward flood.
• Develop flood inundation and hazard map for atleast 2 river basins.
• Educating people and enhancing their awarenessdue to flood disaster preparedness.

2009• To conduct survey via questionnaire to the target
groups with the view to improve the usefulness ofthe FHM• Disseminate the completed FHM to the target
area (River Basin)

2010• Develop and improve technique in developingflood hazard map.
• Review the approach in developing flood hazardand dissemination.
• To review the effectiveness of FHM in terms of
reducing cost of damages/loss of life.

C.4

Problems May A Raise in Making Flood Map in Malaysia
Some of problem which may a raise in making of flood hazard map in Malaysia are
as follows:i.
May not unconditionally acceptable to residents. Land owners and landdevelopers may fear about the fall of land process and oppose to the public
release of the maps;
ii.
Remote sensing methods based on optical, medium resolution imaging such
as Landsat and SPOT, are limited in their applicability;iii.
Temporal limitation of using satellite. For example Landsat only returns overany given location once every 16 days;iv.
Limited of human resources and expertise; andv.
The need for an integrated approach with other agency.

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D.

IMPROVEMENT TO FLOOD HAZARD MAP ON ISE CITY

The improvement has been made to the former flood hazard map are asfollows :i.
Created in the larger scale;ii.
Simple as possible; andiii.
In English
E.

CONCLUSION
i. A flood hazard map is significant only when it is publicly released to residents.
They can be used residents in evacuation and when their lives are in danger. It isnecessary to furnish residents with school education and training once a year or
more and repeatedly disseminate the information through various methods. It isbetter to plan events which will increase the resident’s participation.
ii. Flood hazard maps are not directly related to preventive works, but using flood
hazard maps, it is possible to estimate the cost of damages due to a disaster.
Further, flood hazard maps can be used for the economic evaluation of apreventive work and for Benefit Cost (B/C) analysis. As a result, the priority
order of preventive works can be determined.
iii. It is necessary not only to know the past flood history, but also to collect thedata that is statistically significant to estimate the scale of a phenomenon and todetermine the criteria for forecasting and warning.
iv. Administrative agencies have to undertake the shared functions that are different
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in national, state and village levels. Police, public works, press and transport
have individual functions, but tie-ups among these functions are needed.

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