Water Catchments

Centennial Park Wetlands

Centennial Park is a large urban green space (approximately 2.2 square kilometres in area) which includes parkland, ponds, sports fields, a natural swamp, and large plantings of native trees. The water and vegetation in the park provide habitats for a wide range of native animals, including birds, frogs, reptiles, insects and other invertebrates, eels and other fish, possums, and a large colony of flying foxes. 

[Image: Eastern Long-Necked Turtle, Centennial Park]

Prior to 1788, and the European colonisation the location now known as Sydney, the area of Centennial Park was an important meeting place and a source of fresh water and food for the Gadigal people and Bidiagal people. Following colonisation, traditional custodianship of the area was disrupted.  

There is a source of freshwater in Lachlan Swamp, a small, fenced area of Centennial Park, and the water in the swamp is from a natural freshwater spring. The water flows underground before emerging to the surface in Lachlan Swamp due to the arrangement of underground rocks. The water passing through Lachlan Swamp flows into Lily Pond.

There are another ten ponds in Centennial Park and the water in these ponds is from stormwater (water that comes from rain). Some of the rain falls directly in the park but a lot of the stormwater in the ponds is from rain that falls in the suburbs surrounding the park. The stormwater from outside the park is directed into the ponds via drains and channels.

This map shows the flow of stormwater and freshwater through the ponds in Centennial Park.  

[Image: Map of Centennial Park showing water flow in the Parklands]

The area of Centennial Park makes up about 45% of the water catchment for the ponds. A ‘catchment’ is an area of land where rainwater falls to the ground and then naturally flows from higher areas of the landscape to lower areas of the landscape to collect in ponds, creeks, or rivers.  

In Centennial Park, the highest points are in the Northern and North Western edges of the park and the lowest point is in the South. The ponds in Centennial Park are connected to each other, with water flowing from the highest points to the lowest points. The water leaves the park through Kensington Ponds, and is directed to the Botany Wetlands, and eventually to Botany Bay, which is open to the sea.

The Centennial Park ponds are ‘artificial’ because they were formed by humans, but these constructed wetlands provide important habitat for wildlife in an urban area that is heavily built up with roads and buildings. Stormwater entering the ponds in Centennial Park is carefully managed to make sure the ponds remain a healthy place for plants and animals to thrive.

Management of stormwater in Centennial Park includes:

• Removal of rubbish from stormwater as the water enters the park using ‘gross pollutant traps’ to filter out large items of rubbish
• Controlling the flow of stormwater through channels and pipes to prevent flooding in periods of heavy rain
• Planting aquatic plants that can slow down the flow of water, filter water, and improve water quality
• Planting vegetation on the banks of ponds to prevent soil erosion
• Removal of invasive species, including introduced plants and fish (especially European carp) that are not native to Australia
• Regular testing of water quality to monitor the effectiveness of stormwater management 

[Image: Rubbish caught in the Gross Pollutant Trap in the Centennial Park stormwater system.]