Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí khoa học vật lý quốc tế đề tài: 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 Vol. 18 2 59-79 2007 59 LOSS OF STORAGE AREAS DUE TO FUTURE URBANIZATION AT UPPER RAMBAI RIVER AND ITS HYDROLOGICAL IMPACT ON RAMBAI VALLEY PENANG PENINSULAR MALAYSIA Edlic Sathiamurthy1 Goh Kim Chuan2 and Chan Ngai Weng 3 department of Engineering Science Faculty of Science and Technology Universiti Malaysia Terengganu 21030 Kuala Terengganu Terengganu Malaysia 2National Institute of Education Nanyang Technological University Nanyang Walk 637616 Singapore 3School of Humanities Universiti Sains Malaysia 11800 USM Pulau Pinang Malaysia Corresponding author edlic@ wchan@ Abstract 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 . 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 to times higher for stream point located immediately downstream of the target area . 500 m away compared to further downstream points
