1. a Department of Civil Engineering , University of Canterbury , Private Bag 4800, Christchurch, New Zealand
2. b Centre for Applied Modelling in Water Engineering , School of Civil & Environmental Engineering, The University of Adelaide , Adelaide, SA, 5005, Australia Phone: Fax: E-mail:
3. c Centre for Applied Modelling in Water Engineering , School of Civil & Environmental Engineering, The University of Adelaide , Adelaide, SA, 5005, Australia , +61 8 8303 5874 Fax: E-mail:
4. d Centre for Applied Modelling in Water Engineering , School of Civil & Environmental Engineering, The University of Adelaide , Adelaide, SA, 5005, Australia Phone: Fax: E-mail:
5. e School of Civil & Environmental Engineering, Cornell University , Ithaca, NY, 14853-3501, USA E-mail: