Wetlands

Natural and man-made wetlands play a number of important roles — from providing wildlife habitat and community spaces, to filtering stormwater that enters rivers and creeks.

Wetlands are areas of land temporarily or permanently covered by pools of shallow water. This ranges from fresh to salty, and may be flowing or still.

Some examples of wetlands are:

  • lakes
  • swamps
  • floodplains
  • mudflats
  • estuaries

Natural wetlands

Wetland water is rich in nutrients, attracting and sustaining many different types of plants and animals. Each wetland has a unique ecosystem that provides:

  • food and water
  • habitat and breeding grounds
  • places to shelter during drought

Several wetlands across Melbourne are home to endangered species. Two wetlands we manage are considered by the Ramsar Convention to have international importance:

Man-made wetlands

Some wetlands are built to remove harmful pollutants in stormwater before they reach our rivers, creeks and bays. They can also:

  • reduce riverbank erosion by slowing the flow of water entering rivers or creeks
  • lessen the impact of floods by storing excess water
  • provide space for recreational activities like bushwalking and birdwatching

How wetlands work

Diagram of wetland stormwater treatment process

  1. Water from rivers or creeks is directed into the wetland, and slowly travels through several small ponds. This lets litter, sediment and other large pollutants sink to the bottom.
  2. Water is filtered by micro-organisms and algae that grow on wetland plants. They remove nutrients, especially nitrogen, to help reduce algal blooms in Port Phillip Bay.
  3. After one to three days in the wetland, cleaner water is released back into the river or creek and water levels return to normal.

Looking after wetlands

We manage wetlands differently depending on their main purpose — animal habitat or stormwater treatment.

To protect rare and threatened species that live in our wetlands, we:

  • plant native plants
  • remove weeds
  • control pest animals
  • manage threats from stormwater pollution, salty groundwater and changes to the natural water cycle

We also need to maintain man-made wetlands so they continue working well. This involves removing rubbish and sediment that builds up over time, and replanting vegetation.

Many constructed wetlands also attract birds, frogs and mammals, and are valued by their local community for their amenity. Where possible, we try to balance these needs — for example, delaying maintenance activities to accommodate frog breeding cycles.

Last updated:
1 November 2017