Environmental hydraulics and sustainable water management : proceedings of the 4th International Symposium on Environmental Hydraulics and the 14th Congress of Asia and Pacific Division, International Association of Hydraulic Engineering and Research, 15-18 December 2004, Hong Kong /: proceedings of the 4th International Symposium on Environmental Hydraulics and the 14th Congress of Asia and Pacific Division, International Association of Hydraulic Engineering and Research, 15-18 December 2004, Hong Kong. (2004)