Loss of storage areas due to future urbanization at upper Rambai River and its hydrological impact on Rambai Valley, Penang, Peninsular Malaysia
Sathiamurthy, Edlic , and Goh, Kim Chuan, and Chan, Ngai Weng, (2007) Loss of storage areas due to future urbanization at upper Rambai River and its hydrological impact on Rambai Valley, Penang, Peninsular Malaysia. Journal of Physical Science, 18 (2). pp. 59-79.
Official URL: http://www.usm.my/jps/18-2-07/Article%2018-2-5.pdf
Universiti Malaysia Terengganu. Faculty of Science and Technology. Department of Engineering Science
Nanyang Technological University, Singapore. National Institute of Education
Universiti Sains Malaysia. School of Humanities
Rambai Valley is a coastal floodplain located in Penang northwest coast of Peninsular Malaysia. It is undergoing substantial urbanization at present. This valley is drained by two main channels, Rambai River and Canal 4. The paddy fields of the upper section of Rambai River and Canal 4 (Permatang Rotan) are flood storage areas. They attenuate part of the peak flows that enter the flood prone central region of this valley which is extensively urbanized. This paper through statistical analyses examines the change in potential peak stages resulting from the present and future conversion of upper Rambai River paddy land to urban surfaces. The changes in potential peak stages are simulated using XP-Storm with the purpose of studying the impact of the loss of these storage areas on the downstream floodplain. Channel roughness and surface runoff flow time data were used for model calibration. Simulation results indicated that extensive loss of the paddy fields could lead to higher flood peaks to the immediate downstream sections, i.e. between 9% to 22% for 50% and 100% losses of storage area. The results also indicated that for the same percentage of storage area losses, flood peak stage increases 2.5 to 3.25 times higher for stream point located immediately downstream of the target area (i.e. 500 m away) compared to further downstream points (i.e. 3 to 6 km away) that showed no significant changes. As a whole, the results implied that the increase and propagation of peak stages downstream is not proportional (rational) to the percentage of urbanization and loss of storage areas. The impact of urbanization on peak stage is declines with increasing distance from the target areas.
|Additional Information:||The first author would like to thank Nanyang Technological University, Singapore, for providing scholarship for his doctoral research which results in this paper as one of the publications. The data and help given by the Drainage and Irrigation Department of Malaysia are also very much appreciated. The authors would also like to acknowledge funding from the Universiti Sains Malaysia FRGS Grant 203/PHUMANITI/670061 which enabled the authors to write the final paper.|
|Keywords:||peak flow, floodplain, flood peaks, urbanization, unsteady flow, runoff|
|Subjects:||Q Science, Computer Science|
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