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Curl Curl Lagoon

Our water quality monitoring program has shown Curl Curl Lagoon to have fair water quality. Find out more about the estuary and its unique features.

Curl Curl Lagoon is situated in the Sydney Metropolitan region of New South Wales. It is classed as a small lagoon with an entrance that is intermittently open and closed to the ocean.

Northern Beaches Council have determined a water level height which, when reached, triggers the artificial opening of Curl Curl Lagoon.

Water quality report card

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 have supported Northern Beaches Council develop and carry out a monitoring program to assess the water quality of estuaries in their local government area. Sampling is carried out fortnightly between October and April each year during the warm summer period. One site is sampled in Curl Curl Lagoon.

The monitoring program has been ongoing since 2010. The most recent sampling was completed over the 2023–24 summer.

This report card represents 2 water quality indicators that we routinely measure: the amount of algae present and water clarity. The numerical scores for these 2 indicators are averaged to give the overall grade.

D

Algae

C

Water clarity

C

Overall grade

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

  • algae abundance graded poor (D)
  • water clarity graded fair (C)
  • overall estuary health graded fair (C).

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

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

Go to estuary report cards to find out what each grade means, read our sampling, data analysis and reporting protocols, and find out how we calculate these grades.

The past results of the monitoring program, including detailed water quality report cards, are available on the Northern Beaches Council website.

A view of Curl Curl Lagoon with the Sydney suburb of North Curl Curl in the background and North Curl Curl Beach in the foreground

Aerial view of Curl Curl Lagoon

Local government management

Local councils manage estuaries within their area. Where the estuary is attached to a marine park, marine park management teams are responsible for ensuring compliance with park zoning. Northern Beaches Council manages this estuary.

Threatened species

Estuaries are important to our native animals as they provide food, shelter and breeding grounds.

Read more about the biodiversity in our estuaries.