Secchi Disc data measured during a high rainfall event in Port Jackson, 21 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. Secchi Disc samples were taken along the Port Jackson estuary over four 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.

悉尼港汇水区（Sydney Harbour catchment area）涵盖多条汇入杰克逊港河口（Port Jackson estuary）的河流水系。强降雨事件发生时，该汇水区的水文过程会呈现出不同特征，进而将污染物输送至杰克逊港河口。强降雨条件下，淡水会沿河口密度更高、盐度更大的水体表层滑动，从而快速将污染物输送至相关区域。本次研究在杰克逊港河口沿线开展了为期四天的赛氏盘（Secchi Disc）采样工作，旨在观测淡水羽流（freshwater plume）的运移行为：该羽流以淡水层的形式运移，最终将在河口的特定位置被冲刷带走或发生絮凝沉降。