Port Hacking

Our water quality monitoring program has shown the Port Hacking estuary to have excellent water quality. Find out more about the estuary and its unique features.

Port Hacking marks the southern coastal boundary of the Sydney Metropolitan region of New South Wales. This estuary is classed as a drowned valley.

Port Hacking is tidal up until the Audley Weir, which is located about 12 kilometres from the mouth as the river runs. The estuary offers high aesthetic and recreational value to residents and visitors to the region, and its extensive tidal reaches and fringing bushland support significant biodiversity.

Estuary health and features

Water quality

As part of our water quality monitoring program we assess the water quality and ecosystem health of an estuary using a range of relevant indicators. We sample a subset of the estuaries located between Taree and Wollongong every 3 years. The most recent sampling in the Port Hacking River was completed over the 2019–20 summer when 2 sites were sampled on a monthly basis.

Port Hacking water quality report card for algae and water clarity showing colour-coded ratings (red, orange, yellow, light green and dark green, which represent very poor, poor, fair, good and excellent, respectively). Algae is rated 'good' and water clarity is rated 'excellent' giving an overall rating of 'excellent' or 'A'.

This report card represents 2 water quality indicators that we routinely measure: the amount of algae present and water clarity. Low levels of these 2 indicators equate with good water quality.

The report card shows the condition of the estuary was excellent with:

  • algae abundance graded good (B)
  • water clarity graded excellent (A)
  • overall estuary health graded excellent (A).

Find out more about our estuary report cards and what each grade means. Read our sampling, data analysis and reporting protocols and find out how we calculate these grades.

We have monitored water quality in Port Hacking since 2010. This table shows the water quality grades for this estuary over that time.

Port Hacking historic water quality grades from 2010-11 for algae and water clarity. Colour-coded ratings (red, orange, yellow, light green and dark green represent very poor (E), poor (D), fair (C), good (B) and excellent (A), respectively).

Grades for algae, water clarity and overall are represented as:

  • A – excellent
  • B – good
  • C – fair
  • D – poor
  • E – very poor.

As part of our Beachwatch program we assess swimming suitability at 5 swimming sites in Port Hacking using microbial indicators. We 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 2022. Find out more about how we monitor beach water quality.

Local government area Swim site name Grade
Sutherland Gymea Bay Baths Poor
Gunnamatta Bay Baths Good
Lilli Pilli Baths Good
Jibbon Beach Good
Horderns 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.

Physical characteristics

Estuary type: Drowned valley

Latitude (ºS) –34.7
Longitude (ºE) 151.16
Catchment area (km2) 165.3
Estuary area (km2) 11.7
Estuary volume (ML) 105,261.5
Average depth (m) 9.1

Tidal exchange volume

Tidal exchange volume or tidal prism data is available for this estuary. This tidal prism was measured in 1978.

Tide state Flow
(106 m3)
Local tidal
range (m)
Sydney Harbour
tidal range (m)
Ebb flow 5.53 0.6 0.6
Flood flow 6.98 0.67 0.7
Notes: km2 = square kilometres; m = metres; m3 = cubic metres; ML = megalitres.

Water depth and survey data

Bathymetric and coastal topography data for this estuary are available in our data portal.

Land use

The Port Hacking catchment is relatively undisturbed. The lower estuary dissects a catchment which has the protected bushland of the Royal National Park to the south and the southern edge of Sydney’s suburban sprawl – the Sutherland Shire – to the north. Over 80% of this catchment is undisturbed forest.

National and marine parks

  • Royal National Park is the largest conservation area in this catchment.
  • This estuary does not flow into a marine park.

Community involvement

  • Sutherland Shire Council’s Bushcare Volunteers webpage provides information on the many bushcare groups active around Port Hacking.
  • Greater Sydney Landcare Network is a community organisation and umbrella group for a host of Landcare organisations in the region. They have a number of projects listed on their website and support volunteers to get involved in work to protect, restore and improve the natural environment of Greater Sydney.
Port Hacking

Local government management

Local councils manage estuaries within their area unless the estuary is attached to a marine park. Sutherland Shire Council manage this estuary.