The Berowra Creek estuary is a tributary of the Hawkesbury River. The estuary is fed by a number of local tribuataries that drain the steep catchments adjacent to the waterway.
Berowra Creek is an example of a drowned river valley estuary created in the lower Hawkesbury River valley. The estuary was formed by rising sea levels approximanly 10,000 to 6,500 years ago. Geological data show that sea levels rose rapidly (up to 1.3m/century) over the period beween 18,000 to 6,500 years ago as global ice volumes diminished with warming of the earth’s surface and atmosphere.
The Berowra Creek Estuary is approximately 24 square kilometres long with the tidal limit at Rocky Fall Rapids. The catchment is 310 square kilometres comprising mainly of natural bushland, local tributaries with urban and semi-rural developments along the steep rocky ridges of the upper catchment areas that drain into the waterway. The estuary has a waterway area of approximately 13 square kilometres.