The City of Palmerston boasts 14 man-made lakes and one natural water body that are important ecological and aesthetic assets to the community. They also provide functional outcomes such as stormwater management and water quality treatment.
The lakes are a great place for the community to meet and enjoy, and play an important part of the local ecosystem, providing habitat for fish, birds, and reptiles
To manage these ecosystems the Palmerston Lakes Management Plan has been developed. Part of this plan is a quarterly water quality monitoring program, which provides a quick snapshot of lake health and actions required to maintain lake functions. The latest Lakes Water Quality Report Card can be found here.
Weed management of Council’s lakes includes the management of a number of weeds that grow in the systems.
- Salvinia Molesta
The most significant weed for Council to manage is Salvinia (Salvinia molesta). It is an aggressive, fast growing aquatic weed that form dense mats over waterways. Council have been working closely with Northern Territory Government (NTG) Weeds Branch to ensure an ongoing successful management program is implemented and maintained.
Management of Salvinia is undertaken through mechanical harvesting and biological control. The biological control is a new program of introducing the Salvinia weevil (Cyrtobagous salviniae), which eats only the Salvinia leaves. Through a combined approach of harvesting and the weevils, and the activities of the Lakes Management Plan, the management of Salvinia will be improved and ultimately more sustainable and beneficial to the lake systems.
- Harvesting
The current situation of the lakes is as follows (as of 31 August 2023)Lake weed harvesting maintenance is undertaken on an as needs basis. As well as harvesting and removal of Salvinia weed, some harvesting and removal of Typha reeds and other aquatic vegetation may also be undertaken.
It is noted that the City of Palmerston (CoP) completed bulk cleaning of Salvinia weed from the Palmerston lakes in February 2023. Salvinia, which is one of the world's fastest growing aquatic weeds, remains present in the lakes and is always actively growing. To prevent against excess growth in Salvinia, Cop is constantly surveying the lakes and managing growth via an integrated approach including mechanical weed harvesting, selective aquatic herbicides and Salvinia weevils.
In addition to managing and cleaning the Palmerston lakes of Salvinia weed, lake management and maintenance works include but are not limited to:
• weed spraying and management of aquatic and terrestrial weeds other than Salvinia,
• maintenance of fountains and lakebed aerators,
• sediment trap maintenance,
• maintenance of reeds and other lake-side vegetation to maintain balance between stormwater retention and water quality treatment, amenity, recreational and aesthetic values and uses, and wildlife habitat.Weed harvesters may be deployed to any lake at any time on an as needs basis. The weed harvesting schedule is subject to change at any time having regard to factors such as weather conditions, machinery maintenance and staff etc. Any given timeframes are approximate only.
Please note, harvested lakes are cleaned as far as is practical and may not be fully clear of all weed material.
Lake 10B Durack.
Lake 7A Durack.
Lake 7B Durack.
For more information about City of Palmerston's Lakes Management Plan, press play on the video below.
