The first “post-restoration” monitoring report for Lake Hawdon North is now published

In previous editions of the NGT newsletter we have covered the restoration of Lake Hawdon North in quite a bit of detail, from baseline (pre-restoration) ecological monitoring, through to construction of the new regulator to retain more water in the lake, and some early post-restoration results.

The restoration of this 2,475 ha seasonal wetland located about 10 km inland from Robe has been undertaken by the Australian and South Australian Governments through the Healthy Coorong, Healthy Basin program, with important roles also played by Burrandies Aboriginal Corporation, the Limestone Coast Landscape Board, the South Eastern Water Conservation and Drainage Board, Friends of Shorebirds South East (FoSSE) and Nature Glenelg Trust. The cooperation of adjoining landholders and Agricola Mining (a mining lease covers approximately 10% of the lakebed) has also been, and will continue to be, key to the success of the project.

NGT have played an ongoing role in project development and feasibility, ecological monitoring and project oversight. This month we have published the first post-restoration monitoring report for Lake Hawdon North, covering vegetation and waterbirds. You can download it here, or view it below.

The new regulator was completed in early July 2025 and was then closed to retain water in the lake. With most of the lakebed inundated within 2-3 weeks, and relatively dry conditions prevailing through much of the South East region at the time, thousands of ducks soon arrived to take advantage of the restored habitat, mostly grey and chestnut teal and Pacific black duck.

In October 2025, NGT headed out to undertake the first post-restoration monitoring of vegetation transects that were established in 2021. We shared this work with readers in our November 2025 newsletter but more detail is available in the report.

On 10-12 November, we headed back out to undertake the first post-restoration waterbird survey, joined by FoSSE volunteers and staff from the National Parks and Wildlife Service and Limestone Coast Landscape Board.

Strictly speaking, Lake Hawdon North was not yet fully restored in November 2025. As discussed in previous articles, in addition to constructing a regulator to retain water for longer in the lake, restoration has also involved the removal of recently established thickets of rapidly invading swamp paperbark (Melaleuca halmaturorum). This removal was undertaken to restore the open water / open mudflat habitat that existed 50 years ago.

In November 2025, this task was only about half complete, so although the lake was holding much more water than it had for many years in mid-November, much of that water was not providing the open water / open mudflat habitat favoured by waterbirds that the project aimed to restore. Things will be different in 2026 because swamp paperbark removal is now complete.

Another factor that likely influenced the waterbird count was water levels. Modelling undertaken for the project suggested that, in an average rainfall year, lake levels would peak in early September, then drop such that by mid-November the maximum amount of shallowly inundated mudflat habitat would be present across the lake, likely coinciding with the maximum abundance of migratory shorebirds and other waders.

As it turned out, although 2025 was close to an average rainfall year, water levels when we headed out to count the birds in mid-November were about 20-25 cm higher than the modelling predicted, so much of the lake was too deep for most waders. Although this made surveying the lake challenging, both physically (walking through knee-deep water all day is hard work!) and in terms of counting birds (very large flocks of ducks but not many waders), it was actually a good result. It means the modelling may have been overly conservative, and the restored lake will likely hold water for longer into summer than anticipated.

Migratory shorebird habitat later in the summer becomes more valuable because there is less available across the landscape. In future years, we will use a water-level trigger to initiate the waterbird count, rather than a specific calendar date.

Highlights of the November 2025 waterbird count included:

• observing eight bird species at Lake Hawdon North not recorded in the previous four baseline surveys, including black-fronted dotterel, Eurasian coot, great crested grebe, ruddy turnstone and brown quail;
• 387 red-necked stint, the highest yet recorded count of this migratory shorebird at the lake;
• a nationally significant count of sharp-tailed sandpiper (1204);
• a nationally significant count of Latham’s snipe (219), a cryptic species only counted opportunistically.

For more detail, please delve into the report!

The restoration of Lake Hawdon North was supported by the Australian Government and the Government of South Australia under the Healthy Coorong Healthy Basin program.