Swans and cygnets

Warringah has six main catchments: Cowan, Middle Harbour, Narrabeen, Dee Why, Curl Curl and Manly. There are also a number of smaller catchments that drain directly to some of our beaches. 

To manage and protect our catchments we undertake many activities including; water quality monitoring, creek rehabilitation, bush regeneration, animal corridor protection, stormwater management, and wetland rehabilitation.

What is a Catchment? 

A catchment is an area of land, bound by hills or mountains from which all runoff water flows to the same low point, such as a lake, dam, river, estuary or lagoon where it enters the ocean. Rainwater will flow to this lowest point, via creeks, rivers and stormwater systems.

Our catchments are grouped based on current ecological values and catchment land uses:

Group A: very high ecological value

Group B: some degradation in the upper catchments, but high ecological value downstream

Group C: generally of low to moderate ecological value with moderate to highly developed catchments

As well as rainwater, groundwater, stormwater and wastewater flow to the lowest point in a catchment.  Catchments are connected from top to bottom, so what happens upstream in a catchment influences conditions downstream. 


In this section you can find

Narrabeen Lagoon


Learn about our major lagoons and how we can all work to protect them.
Manly Dam

Manly Dam Environment

Manly Dam is one of Sydney's largest freshwater lakes.
Snake Creek

Other Catchments

Warringah has catchments draining to Middle Harbour, the Hawkesbury and our beaches.


There are 230km of creeks in Warringah.