Sonde data measured during a high rainfall event in Port Jackson, 23 August 2007.

The Sydney Harbour catchment area includes a number of different river systems which drain into the Port Jackson estuary. During high rainfall events the catchment areas behave differently to deliver contaminants into the Port Jackson estuary. Under conditions of high rainfall contaminants are delivered to areas very quickly as freshwater slides over the top of the denser more saline waters of the estuary. Sonde samples, for measurement of conductivity, salinity, turbidity and temperature; were taken along the Port Jackson estuary over three days to determine the behaviour of the freshwater plume as it travels in a layer of freshwater to be flushed or flocculate out at some point in the estuary.

悉尼港集水区包含多个汇入杰克逊港（Port Jackson）河口的河流水系。强降雨事件期间，该集水区会以独特的输运方式将污染物输送至杰克逊港河口。在强降雨条件下，淡水会漂浮在河口密度更高、盐度更大的水体表层快速流动，从而将污染物快速输送至各处区域。研究团队在为期三天的时间内沿杰克逊港河口采集样本，使用水质探头（Sonde）测量电导率、盐度、浊度与温度，以解析淡水羽流的运移行为——该羽流以淡水层形式运移，并将在河口的特定区域被冲刷或絮凝沉降。