A new tool for estuary managers – the Estuary Entrance Management Support System
By Graeme Jeffery, Glenelg Hopkins CMA
| Estuary management in Victoria has received a boost with the development of a new decision support tool called the Estuary Entrance Management Support System (EEMSS). Estuaries are one of our most valuable natural assets, providing spawning and nursery grounds for fish and breeding and foraging areas for birds. They are also a popular tourist destination and provide important recreational opportunities such as fishing, bird watching and boating. They are also highly complex natural environments. In Victoria many estuaries intermittently close following the formation of a sand bar at the mouth of the estuary. This is a natural process and results in increased water levels in the estuary. High water levels bring significant environmental benefits when adjoining wetlands and fringing vegetation are flooded. |  |
However the land around estuaries has also become a focal point for development due to the fertile nature of floodplain land and the obvious benefits of living near a picturesque open water-body. In order to reduce the impact of high water levels on socio-economic assets, it is often necessary to open closed river mouths artificially. This is commonly done with heavy machinery but can also be done by hand in some cases.
Artificial river mouth openings can carry a high risk of damage to the health of the estuary. An obvious risk is causing a mass fish kill. This has occurred several times in Victoria as a result of artificial openings being done under the wrong conditions. Less obvious but possibly no less damaging are risks of contributing to the long-term decline in estuary health as a result of impacts such as premature drainage of wetlands and the disruption of fish spawning.
Developed by Deakin University through a project funded by the Australian Government’s Natural Heritage Trust, the EEMSS provides estuary managers with a powerful tool for properly accounting for all of the likely risks involved with decisions to artificially open a river mouth, or conversely a decision not to artificially open. In addition to its use as a decision support tool, the EEMSS also provides sound guidance for the management of estuaries overall through the establishment of important baseline data such as records of river mouth openings, water levels, water quality data, and species lists. This information can be stored and queried through the database function of the system
Development of the EEMSS was guided by a multi-agency steering group and community consultation was key to the development process. The EEMSS was trialled with local communities at four estuaries in southwest Victoria and the system has been well received by these communities.
Implementation of the EEMSS at Victoria’s seasonally closed estuaries will occur over the next 12 months.
For further information contact Graeme Jeffery at the Glenelg Hopkins CMA email at g.jeffery@ghcma.vic.gov.au or phone (03) 557 12526.