This Paper was presented by Aquatic Systems Officer Christina Day at a National Conference
Christina Day 1, Ian A. Wright2, Amy St Lawrence1, Robert Setter1, Geoffrey Smith1
- Environment Branch, Blue Mountains City Council, Locked Bag 1005, Katoomba, NSW, 2780. email@example.com
- School of Science and Health, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751. firstname.lastname@example.org.
- The recently registered SharkTM Aquatic Herbicide (240g/L carfentrazone-ethyl) was used at Glenbrook Lagoon to treat an infestation of cabomba, one of the first applications of this scale in Australia.
- Water quality and ecological effects were monitored to determine the impacts of the herbicide on a large natural water body.
- One year later, monitoring programs show a return to healthy dissolved oxygen levels; a healthy population of native fish and turtles; and no evidence of cabomba or weed water lily.
- This case study highlights the challenges involved with planning and implementing a large scale aquatic weed control program and the importance of understanding and careful consideration of the current physical, chemical and biological conditions of the individual water body being targeted.
Download the full Glenbrook Lagoon paper at:
Turtles, fish and other aquatic life is thriving at Glenbrook Lagoon, – once the most polluted waterway in the Blue Mountains, – thanks to a successful seven-year restoration program involving the local community and funded by Council’s Environment Levy.
Recent surveys of the lagoon, conducted by Council, have revealed healthy populations of Eastern long-necked turtles, Flat-headed gudgeon, Australian smelt, eels and catfish. Pollution-sensitive water insects that have not been seen in the lagoon for many years are also on the rise, – which means water quality is improving.
Above the water line, local residents have reported that the lagoon is looking more ‘alive and inviting’ as the environment recovers.
Less than a decade ago, Glenbrook Lagoon was in poor shape, acting as a sink for stormwater runoff from surrounding neighbourhoods. High levels of water pollution led to an explosion of two aquatic weeds – Cabomba and Salvinia – which were literally choking the lagoon to death.
Cabomba and Salvinia are Weeds of National Significance, – members of Australia’s ‘most wanted’ list of invasive, destructive weeds. Cabomba, – an aquarium escapee, – is particularly virulent, and posed a potentially serious threat to Sydney’s nearby water supply, as well as waterway health, fisheries, recreation and tourism downstream.
Since the mid 1990’s, Council has been working on a long-term project to bring Glenbrook Lagoon back to life; installing systems to reduce stormwater pollution, combatting noxious weeds in and around the lagoon, replanting native species, supporting local Bushcare and Clean Up Australia efforts, and raising community awareness.
In a national first for such a large natural water body, the Council has cleared 99.9% of Cabomba and Salvinia. Water quality is improving, bushland habitats around the lagoon are steadily recovering and less pollution is flowing into the lagoon. The Council is also continuing to monitor the lagoon’s status.
To fund Cabomba control, the Council secured a $280,000 Caring for Our Country grant from the Federal Government, with $200,000 in matching funds provided by Council’s Environment Levy. The Council’s Environment Levy raises around $1.5 million annually from Council rates and funds projects to restore local creeks, improve water quality, control noxious weeds, protect endangered species and improve walking tracks across the City.
Mayor, Cr Mark Greenhill, said, “With its peaceful setting, open spaces and birdlife, Glenbrook Lagoon is a true local gem of the lower Blue Mountains. It’s exciting for both the local community and the environment that this little oasis is returning to life.”
“Glenbrook Lagoon is just one of 50 waterway sites regularly tested for water quality and one of 130 bushland sites currently being rehabilitated by Council; work which is made possible through Council’s Environment Levy.”
The Council will continue to track the lagoon’s water quality through its aquatic monitoring program, which provides scientific information on the health of local waterways and guides Council’s management of these areas. See the results of the Council’s water quality monitoring program at: www.bmcc.nsw.gov.au/sustainableliving/environmentalinformation/livingcatchments
A Council aquatic weed control program funded partly by the Blue Mountains Environment Levy and partly by the Federal Government’s Caring for our Country initiative is dramatically improving the condition of Glenbrook Lagoon by tackling a water-weed infestation that has ‘choked’ the lagoon for many years. Continue reading