Field observations in a small subtropical estuary during and after a rainstorm event

In Australia, a large majority of small subtropical estuaries are narrow, elongated and meandering channels with large width to depth ratio and cross-sections which deepen and widen towards the mouth. Up to date, episodic rainstorm events in such small systems were rarely documented, and this study presents a field data set collected during and immediately after a rainstorm. A number of hydrodynamic and physio-chemical parameters were recorded simultaneously at several longitudinal locations for 12 h. The field measurements demonstrated a significant flushing of the estuarine zone, caused primarily by the rainfall runoff from the nearby shopping malls and roadways. Some strong vertical stratification of the water column was observed at all sampling locations, and the depth-averaged salinity data exhibited a dome-shaped intrusion curve. A solution of the salt dispersion equation provided some agreement with the freshwater flushing conditions during the wet weather.