1. Senior Lecturer, River Engineering and Urban Drainage Research Centre (REDAC), Univ. Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang, Malaysia (corresponding author).
2. Professor, REDAC, Univ. Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang, Malaysia.