1. Professor of Civil Engineering, Univ. of Wollongong, Wollongong City, NSW 2522, Australia (corresponding author).
2. Senior Water Engineer, Snowy Mountains Engineering Corporation, Level 6, 76 Berry St. North Sydney, NSW 2060, Australia.
3. Lecturer, School of Civil Engineering, Univ. of Wollongong, Wollongong City, NSW 2522, Australia.