Saltwater intrusion in the Pearl River Estuary during winter

Abstract

An intensive observation and a three-dimensional finite-difference model of Environmental Fluid Dynamic Code were used to study saltwater intrusion in the Pearl River Estuary. The model simulation was carried out for December 2007 to February 2008, which covered the in situ observation. The model was forced by observed winds, tidal elevation at open boundaries, and river discharges from eight inlets in the Pearl River Estuary. The agreements with observation were verified in terms of current, salinity and tide elevation. Using the computed tidal current, the residual current was also calculated to estimate material transport. In addition, the Lagrangian method was used to track the trajectory of particles from the mouth of Humen and Modaomen inlets. By computing the flushing time of these two channels, the authors find that there exists close relationship between flushing time and saltwater intrusion. Potential impact of sea-level rise on saltwater intrusion was also studied. Sensitivity experiments indicate that sea-level rise can impact on the saltwater intrusion in the Pearl River Estuary, such as increasing salinity concentration and intrusion distance, especially during neap tide in winter (dry season).