Based on EFDC (Environmental Fluid Dynamic Code) model

a three dimensional numerical hydrodynamic and sediment transport model in Pearl River network of Guangzhou (PRGZ)

was developed. The result indicated that the model was able to simulate hydrodynamics and sediment transport characteristics with fairly good accuracy verified by typical flood scenario case in July 1999 and dry scenario case in February 2001. The sediment transport result showed that Pingzhou to HouHangdao were the major transportation channel for suspended sediment during flood season. Erosion and deposition simulation also showed that PRGZ tended to deposition in flood season with Nanhandao and Lijiaoshuidao as the major deposition area. In the dry season

PRGZ tended to erosion

which usually happened in Shabeihai

Qianhangdao upper section and Xinzao rivernet. Besides

the entire rivernet showed a slow deposition rate

approximately at a speed of 2.0 cm/a.