Malaysian Journal of Analytical Sciences, Vol 19 No 5 (2015): 1109 - 1119 1109 MALAYSIAN JOURNAL OF ANALYTICAL SCIENCES Published by The Malaysian Analytical Sciences Society ASSESSMENT OF WATER SALINITY MODEL USING HYDRODYNAMIC NUMERICAL MODELLING IN ESTUARY OF SELANGOR RIVER, MALAYSIA (Penilaian Kemasinan Air Menggunakan Pemodelan Model Berangka Hidronamik di Muara Sungai Selangor, Malaysia) Mohd Ekhwan Toriman 1,2 *, Norbaya Hashim 3 , Mohd Khairul Amri Kamarudin 1,4 , Abdul Jalil Hassan 3 , Muhammad Barzani Gasim 1 , Asyaari Muhamad 1,5 , Nor Azlina Abd Aziz 1 1 East Coast Environmental Research Institute (ESERI), Universiti Sultan Zainal Abidin, 21300 Kuala Terengganu, Terengganu. Malaysia 2 School of Social, Development and Environmental Studies, Faculty of Social Sciences and Humanities, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia 3 Hydraulic Engineering Division, National Hydraulic Research Institute of Malaysia (NAHRIM), 43300 Seri Kembangan, Selangor, Malaysia 4 Faculty of Design Arts and Engineering Technology, Universiti Sultan Zainal Abidin, 21300 Kuala Terenganu, Terengganu. Malaysia 5 Institute of The Malay World and Civilisation (ATMA), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia *Corresponding author: ekhwantoriman@gmail.com Received: 14 April 2015; Accepted: 9 July 2015 Abstract Issues such as water pollution and extraction of water from Sungai Selangor system has been said to be the cause of ‘fading fireflies’. Salinity intrusion into estuary of the Sungai Selangor has been carried out on a hydrodynamic numerical modeling to access the parameter that governed the amount of salt in the river. The berembang trees on the river bank that become the fireflies’ habitat need some amount of salt for proper growth. Living at the lower reaches of Sungai Selangor, the fireflies are affected not only by the activities in their vicinity, but by activities in the entire river basin. Rapid economic development in the basin and the strong demand for the water resources puts pressure on the ecosystem. This research has been carried out to investigate the effect of water extraction along Sungai Selangor towards altering the amount of salt content in the river. The hydrodynamic modeling with regards to the salt content is expected to support long term assessment that may affect the berembang trees as a result of changes in the flow from upstream because of the water abstraction activity for domestic water supply. Keywords: hydrodynamic modeling, numerical modeling, water extraction, estuary, water salinity model Abstrak Isu-isu seperti pencemaran air dan pengeluaran air dari sistem Sungai Selangor telah dikatakan punca 'kelip-kelip pudar. Pencerobohan kemasinan ke muara Sungai Selangor telah dijalankan ke atas model berangka yang hidrodinamik untuk mengakses parameter yang dikawal jumlah garam dalam sungai. Pokok-pokok berembang di tebing sungai yang menjadi habitat kelip-kelip 'memerlukan jumlah garam untuk pertumbuhan. Hidup di muara Sungai Selangor, kelip-kelip terjejas bukan sahaja oleh aktiviti-aktiviti di sekitar mereka, tetapi oleh aktiviti di lembangan sungai keseluruhan. Pembangunan ekonomi yang pesat di lembangan dan permintaan yang kukuh untuk sumber air meletakkan tekanan ke atas ekosistem. Kajian ini telah dijalankan untuk mengkaji kesan pengambilan air di sepanjang Sungai Selangor ke arah mengubah jumlah kandungan garam di dalam ISSN 1394 - 2506