3-dimensional water quality and hydrodynamic modelling in Hong Kong I. Concepts and model set-up

The Hong Kong Special Administrative Region (HKSAR), PRC is located on the southeastern side of the Pearl River Estuary. The river discharges 336 billion m 3 of freshwater runoff a year into the estuary carrying large quantities of sediment and nutrients which characterise the hydrographic and water quality condition in the region, especially during the wet season. A suite of 3-dimensional hydrodynamic and water quality models has been set up for the Hong Kong SAR Government to assess the water quality impact of sewage disposal schemes and engineering developments. This paper discusses the hydrographic and water quality characteristics in Hong Kong and the nearby region, model features required to incorporate the important characteristics and complicated coastline of Hong Kong, field surveys conducted and model set-up for calibration and verification of the 3-dimensional models.