Broken Bay is situated in the Greater Sydney region of New South Wales. It is a tide-dominated drowned valley estuary with an open entrance.
Broken Bay, is large oceanic bay located about 50 kilometres north of Sydney. It separates Greater Sydney from the Central Coast and is the first major bay north of Sydney Harbour.
Broken Bay is the meeting of the Hawkesbury River, Pittwater, and Brisbane Water. The area has high recreational value and high economic value in prawn, lobster and various fin fish commercial fisheries in Broken Bay and surrounding waters.
Broken Bay has not been sampled as part of our monitoring program. We monitor water quality in Pittwater, Hawkesbury River and Brisbane Water, the main tributaries of Broken Bay. These tributary estuaries were last sampled in 2020–21.
As part of our Beachwatch program we assess swimming suitability at 3 swimming sites in Broken Bay using microbial indicators. Central Coast Council collect samples at each site weekly between October and April, and monthly from May to September, to calculate the suitability grade. Sampling is ongoing. Each grade reflects the most recent 100 water quality results to April 2021. Find out more about how we monitor beach water quality.
| Local government area | Swim site name | Grade |
|---|---|---|
| Central Coast | Pearl Beach Rockpool | Good |
| Umina Beach | Good | |
| Ocean Beach | Good |
Estuarine, lake and lagoon water can sometimes be unsuitable for swimming, especially after rainfall when stormwater and wastewater can overflow into swimming areas. Learn more about what the grades mean and how we grade swimming sites on our beach classification webpage.
Water sampling and laboratory analysis was funded by Central Coast Council.
Estuary type: Drowned valley
| Entrance location |
Latitude (ºS) | –33.56 |
|---|---|---|
| Longitude (ºE) | 51.34 | |
| Catchment area (km2) | 12.9 | |
| Estuary area (km2) | 17.1 | |
| Estuary volume (ML) | 167,615.0 | |
| Average depth (m) | 9.8 | |
The Broken Bay catchment is a low to moderately disturbed. Urban residential areas are mostly located to the north of the bay in Umina and to the west surrounding Pearl Beach. A number of forested conservation areas are located within the catchment.
Local councils manage estuaries within their area unless the estuary is attached to a marine park. Central Coast Council manage this estuary.