Victoria’s estuaries

Estuaries are semi-enclosed bodies of water where salt water from the sea mixes with freshwater flowing from the land. Estuaries are dependent on both sources of water to provide a healthy environment. Estuaries are diverse in their physical form as they are in their state of health. However, they all share the distinction of being highly valued by the small communities living alongside them.

Over 120 rivers, streams and creeks enter the sea along Victoria’s coastline including those that run into major embayments like Port Phillip Bay, Western Port Bay and Corner Inlet, as well as riverine sub estuaries of the Gippsland Lakes, Victoria’s largest estuary.

Victoria’s estuaries include systems that are permanently open to the sea or close intermittently as a result of sand bar formation at the estuary entrance. This usually occurs during periods of low freshwater flow. Intermittently closed estuary entrances are a natural feature of the Victorian coastline and can be critical to the ecology and physical form of estuaries. Victoria’s estuaries, particularly those that are intermittently closed can be highly variable environments changing with tides, sea state, rainfall and wind patterns. Salinities in estuaries can vary from fresh to saltier than the sea.

Estuary values

Estuaries in Victoria are highly valued for their social, environmental and economic characteristics. Estuary managers must carefully balance their management activities to ensure the most beneficial outcomes are achieved for the environmental, social and economic values. The decision of whether to open or not open an estuary mouth artificially must consider all three values . An example of this could be that artificially opening an estuary to protect agricultural land or roads from flooding by may adversely impact fish spawning if undertaken at a critical time in the year.

Environmental values