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.
The weed Kan Kong (Ipomoea aquatica) is known to be predominantly growing in Sanctuary Lakes. This being treated and removed as required. Para grass (Urochloa mutica), Peruvian water primrose (Ludqidgia peruvia) and Olive Hymenachne (Hymenachne amplexicaulis) are also being managed across our lakes systems.
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.
Weed harvesting is underway. There is currently a back-log of lakes requiring harvesting due to the harvester not being operational for several months. Forward schedules for harvesting only includes the next three lakes to be targeted, as it is difficult to determine the length of time needed between lakes. These lakes have been chosen according to their weed coverage, current poor water quality and potential ecological impacts from the Salvinia (i.e. effects on native fauna).
The schedule is constantly reviewed and updated to ensure that critical areas are targeted as required.
Weed harvesting is underway in the Durack lakes system. Lakes are regularly inspected and assessed for weed coverage and water quality. The schedule is regularly updated to ensure the critical areas at a point in time are targeted. There is currently a back-log of lakes requiring harvesting due to the harvester not being operational for several months.
The current situation of the lakes is as follows:
Durack Lakes: 1A, 1B, 3, 9 and 10 cleared
Marlow Lagoon: cleared
Sanctuary Lakes: cleared
Currently clearing: Durack Lake 5
Next lake to clear: Durack Lake 8 (approximate timing November 2021)
Please note, lakes harvested may not be fully cleared of all weed material. Timeframes are approximate only, this information will be updated as additional lakes are being treated.
For more information about City of Palmerston's Lakes Management Plan, press play on the video below.