Works at Yeramba Lagoon, Georges River National Park, have restored tidal flushing to the lagoon. In late-August, works got underway to progressively drain the freshwater lagoon and remove the existing weir. Since then, an adjustable height weir has been installed, and tidal flow reintroduced. Saltwater is now flowing into the Yeramba Lagoon on the higher tides – and the weed is dying off quickly.
Here you can see the tidal flow in action. The tidal flow will transform the previously weed-infested freshwater lagoon by sustainably removing exotic species, improving water quality, and increasing the estuarine wetland in the area.
In addition, Freshwater and tidal wetland provide ideal breeding areas for mosquitos. The change of hydrology through tidal flow and the removal of aquatic weeds is anticipated to decrease the number of mosquito larvae.
Interestingly, saltwater intrusion into freshwaters is predicted to be a major driver of ecosystem changes as a result of rising sea levels. The reconnection of the freshwater lagoon to tidal flows can provide an opportunity to observe changes in populations and species which is fundamental in understanding the impact climate change will have on existing food chains and populations of coastal freshwater habitats.
Congratulations to NSW National Parks and Wildlife Service for all their hard work on this project. And thank you to NSW DPI’s Flagship Fish Habitat Action Grant program, funded under the Saltwater Recreational Fishing Trust, for funding the project. Thanks also to David Coleman for helping to secure funds to manage the weeds.
Tidal flow at Yeramba Lagoon.