Baseline ecological monitoring at Lake Hawdon North, near Robe, SA

Lake Hawdon North is a large (2,475 hectare) seasonal wetland located about 15 km east of Robe. From 1915, Drain L, the highest yielding artificial drain in the South East of SA, was excavated through the bed of Lake Hawdon North. Since then, the water regime of the wetland has been severely compromised. Although the wetland continues to inundate extensively most years, the duration of inundation is much shorter than it originally would have been.

As a result of its natural sill (or full-supply) level being breached, Lake Hawdon North is typically dry by early December. This means that it has very little habitat value for the tens of thousands of migratory shorebirds that migrate to the Limestone Coast region from the arctic circle and spend the Australian summer feeding in shallow wetlands.

The feasibility of restoring Lake Hawdon North is being investigated through the Healthy Coorong, Healthy Basin program, which seeks to provide alternative habitat for migratory shorebirds due to the currently degraded condition of the Coorong South Lagoon. Restoration would involve construction of a regulator on Drain L that could hold water for longer in the lake, extending shallow inundation through to late summer/early autumn. This would greatly improve the value of the wetland as habitat for migratory shorebirds and a range of other species. It is a significant and important wetland restoration project for which NGT ecologists have been advocating for many years.

Micha Jackson and Abhishek Gopalakrishnan from the University of Adelaide at Lake Hawdon North, 8th September 2021.

NGT is playing several roles in this project, including designing a baseline ecological monitoring program that will enable the ecological outcomes of the project, should it be implemented, to be measured. Despite its size, there has been relatively little biological survey work done at Lake Hawdon North. For example, we know very little about current migratory shorebird use of the area. The image above was taken on a recent reconnaissance visit to the lake with researchers from the University of Adelaide, who are collaborating with NGT on the project.

We will keep you informed as this important ground work continues.

The South Australia Government’s Healthy Coorong, Healthy Basin Program is jointly funded by the Australian and South Australian governments.

Ben Taylor