http://redac.eng.usm.my/html/projects/flood%20risk%20map/Sg.%20Pahang.htmlProject
Title: Digital Flood Mapping: Case Study Of 2007 Sungai Pahang
FloodFunder: Research University GrantDuration: 15th August 2009 -
14thAugust 2011
Researchers: Prof. Aminuddin Ab Ghani Prof. Nor Azazi Zakaria
Zorkeflee Abu Hasan Leow Cheng Siang Chang Chun Kiat
Executive Summary:Several major floods have been experienced in
Malaysia for the last few decades. Flood occurrences seem to be
getting more frequent in recent years, especially in some cities
like Kuala Lumpur, Penang and Kuching where rapid urbanisation is
taking place. After several dramatic flooding events struck the
country with dramatic lives and property losses since the 1960s,
the government has taken several positive steps and seriously
planning to envisage flood mitigation projects in its national
plans, translated substantially by the establishment of the Natural
Disaster Relief Committee in 1972 and the Permanent Flood Control
Commission in December 21, 1971 purposed for to study short-term
measures to prevent the occurrence of floods and long-term measures
for flood mitigation. In this study, results are presented to
develop a digitally flood map for the 2007 flood inundation areas
along Sungai Pahang by gathering hydraulic and hydrologic data.
This will allow a proper evaluation on the impact of future flood
events and advise the implementing agencies as to what steps need
to be undertaken to provide further preventative measures to avoid
the anticipated flood problems that might occur.Research
Background:Malaysia is fortunate in that historically it has not
experienced natural disasters in the form of earthquakes,
volcanoes, and typhoons. The most common natural disaster
frequently encountered in Malaysia is flooding. Two major types of
floods occur in Malaysia, including monsoon floods and flash
floods. The Department of Irrigation and Drainage (DID) in Malaysia
has estimated that about 29,000 sq. km, or 9%, of the total land
area and more than 4.82 million people (i.e. 22% of the population)
are affected by flooding annually. The damage caused by flooding is
estimated to be about RM915 million (Chan, 2005). Whilst monsoon
floods are governed by heavy and long durations of rainfall, more
localized flooding, which occurs especially in newly developed town
areas, has been reported more frequently in recent years. In
October 2003 major flooding affected a large area in the
northwestern part of the Peninsular, including the states of Kedah,
Penang and Northern Perak. The December 2007 flood (Figure 1), on
the other hand, occurred in the state of Pahang, after more than 30
years (DID, 1974) since the last similar floods of 1971 (Figure 2,
Tables 1 and 2). Flash floods have occurred more frequently in the
country since the 1980s, with these types of floods often having a
drastic impact on parts of the country. Two common approaches
adopted in reducing the impact of flood problems have been
increasingly adopted in Malaysia and these include structural and
non structural measures. Structural measures include such measures
as river widening, deepening and straightening, with the aim being
to reduce the magnitude of the flood, but at the same time this
approach often transfers the flooding problem further downstream.
For non structural measures, tools such as computer models can be
used to quantify the effects of human interference to the river
system. Such tools are already available widely used in many
countries worldwide, but the application of sophisticated models is
still relatively new in Malaysia (Chang et. al 2008, Leow et al.
2009). One reason for this limited use of such models in Malaysia
is that the tools often do not properly model the more extreme
flood events, where the river flows are often supercritical. In
Malaysia it is regarded as increasingly important to carry out a
thorough analysis of flood events with the help of available river
models to understand the flood behaviour before any structural
measures are undertaken. Therefore, before any amendments are
implemented within a catchment and the flood plain, river engineers
must evaluate the potential extent and impact of flood events and
advise the implementing agencies as to what steps need to be
undertaken to provide further preventative measures to avoid the
anticipated flood problems that might occur (Ab. Ghani et al.
2009).The present research will provide the required data on flood
inundation of 2007 Sungai Pahang flood for future computer
modelling purposes.
Figure 1: December 2007 flood at Pekan, Pahang
Figure 2: January 1971 flood profile (DID, 1974)Table 1: Water
Surface Slope in January 1971 flood (DID, 1974)Table 2: Flood Slope
in January 1971 flood (DID, 1974)Objectives of the Research: a) To
gather hydraulic and hydrologic data of the 2007 flood b) To
digitally map the 2007 flood inundation areas along Sungai Pahang
c) To estimate damage cost due to 2007 flood Study Area:Sungai
Pahang is the longest river in the Peninsular Malaysia at 435 km,
the river drains about three quarters of the land area in the state
of Pahang (Figure 3). Sungai Pahang actually begins from Kuala
Tembeling at the confluence of two equally large and long rivers,
the Jelai which drains from the eastern slopes of the Banjaran
Titiwangsa, the main range of Peninsular Malaysia, and the
Tembeling which has its headwaters in the Terengganu Highlands in
the east. Other main tributaries of Sungai Pahang are the Semantan,
Teriang, Bera and lepar.Four major towns are located on or near
Sungai Pahang and its tributaries: Pekan, the royal town at its
mouth; Temerloh midway on the river at its confluence with
Semantan; Jerantut, the gateway to Taman Negara on the Tembeling;
and Kuala Lipis at the mouth of the river bearing the same name on
the Jelai.
Figure 3a: Pahang River Basin (DID, 1974)
Figure 3b: Satellite Image coverage on the Study Area
Figure 4: On-Site Ground Survey and Validation using
Professional Data Mapper for GPS Data Collection and Mapping
Figure 5: DEM Development
Figure 6: Comparison of Flood Inundation Area of Model with
Actual Condition
Figure 7: Proposed Flood Mitigation Alternatives for Sungai
PahangSelected Publications: Ab. Ghani, A., Chang, C.K., Leow,
C.S., & Zakaria, N.A. (2012). Sungai Pahang Digital Flood
Mapping: 2007 Flood, International Journal of River Basin
Management, pp. 1-10, DOI: 10.1080/15715124.2012.680022.
Azamathulla, H.Md., Ab. Ghani, A., Leow, C.S., Chang, C.K. &
Zakaria, N.A. (2011). Gene-Expression Programming for the
Development of a Stage-Discharge Curve of the Pahang River, Journal
of Water Resource Management,DOI: 10.1007/s11269-011-9845-7.
References: Ab. Ghani, A., Zakaria, N.A. & Falconer, R.A.
(2009). Editorial, River Modelling and Flood Mitigation: Malaysian
Perspectives, Water Management Journal, Vol. 162, No.1, pp. 1-2,
ISSN 1741-7589. Chan, N.W. (2005). Sustainable Management of Rivers
in Malaysia: Involving All Stakeholders, International Journal of
River Basin Management, Vol. 3, No. 3, pp. 147-162, ISSN:
1571-5124. Chang, C.K., Ab. Ghani, A., Abdullah, R. & Zakaria,
N.A.(2008). Sediment Transport Modeling for Kulim River: A Case
Study. Journal of Hydro-Environment Research, IAHR, Vol. 2, No.1,
pp. 47-59, ISSN: 1570-6443. Department of Irrigation and Drainage
or DID (1974). Pahang River Basin Study, Vol. 3: Basin Hydrology
and River Behaviour. Leow, C.S., Abdullah, R., Zakaria, N.A., Ab.
Ghani, A. & Chang, C.K. (2009). Modelling Urban River
Catchment: A Case Study in Malaysia. Water Management Journal,
Institution of Civil Engineers (ICE), UK, Vol. 162, No.1, pp.
25-34. ISSN 1741-7589.