| Summary: | Flood is one of the natural disasters that frequently OCCUlT d particularly in Peninsular
Malaysia. In December 2014, a major flood hit the East Coast of Peninsular Malaysia
which resulted in a variety of implications for the environment, particularly effects of
flood to river planform and geometry. The objectives of this research are to investigate
the effect of 2014 major flood on river planform and geometryin the mainstream of
Pahang River. The study is divided into three stages, namely the upstream, middle
stream and downstream of the Pahang River.Type of Lateral Change (TYLAT), Mode
of Meander Movement (MOME), and Sinuosity Index method are used to classify and
evaluate the river planform changes based on the satellite images from 2010 (before
flood) and 2015 (after flood). Bathymetric analysis with the support of Surfer and
Geographic Information System ArcGIS software were conducted to display the
changes of river's geometry shapes due to 2014 flood. The results obtained reflect
change f Meander Progression and changes in Increasing Amplitude indicate high
numbers of cases. Respectively, 36 cases and 24 cases were concentrated in the
upstream of Pahang River. Braiding changes focused on the downstream of Pahang
Riverat Pekan recorded five cases. MOME changes ofExtension and
Translationevidently occurred at a high level at upstream, which recorded 23 cases and
14' ca es respectively. Sinuosity Indexof Pahang River shows high percentage of
changes occurs in the up tream at Tembeling River and Jelai River with the highest
percentage recorded at 45 percent. Sinuosity Index recorded at middle stream shows a
significant change with the percentage of 20.7 percent. While at downstream, the
inuosity Index recorded three significant changes from 16.0 to 20.3 percent. Based on
statistical analysis, significant changes with moderate correlation in R squared value
atR2 = 0.6669 was obtained between Sinuosity Index changes and water level that
occurred from 2010 to 2015.Meanwhile, using Kriging Interpolation method, local
rainfall distribution in the Pahang River Basin shows a high amount of fall occurrence.
The concentration area of rainfall recorded was on the highlands, which are located at
the North West of Pahang River Basin. Cumulative rainfall increased from 1300mm to
1670mm in December 2014. In January 2015, cumulative rainfall in the Pahang River
Basin decreased to 200 mm to 161 mm. In future, for mitigation measure, alternative
management is proposed for Pahang River Maintenance such as service of natural flood
ponds and flood mitigation projects. Generally, this study is very important to gather
information on the effect of 2014 major flood in Pahang River in order to manage the
Basin of Tropical River.
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