Wetland Restoration on Private Land Case Study 2: Coleraine District

Nature Glenelg Trust has recently installed another wetland restoration structure, with the support of an enthusiastic landholder on a large cattle and sheep property located in the Coleraine district in South West Victoria.

This project was driven by the landholder’s strong interest in sustainable environmental management on the property and the wider district, and aims to encourage a resurgence in native wildlife visiting the property.

The wetland restoration structure was installed within an existing artificial drainage channel, which during flow events can flow in either direction (adding a degree of site complexity), but was typically resulting in the artificial drainage of the wetland once winter inflows had ceased – impacting on the depth and duration of inundation into the drier months. Hence, the design brief was to have a structure that could both: (a) let water flow into the wetland via the shallow gradient drain when the downstream dam is full, but also (b) be used to restrict water draining out of the wetland, once the downstream dam level recedes in the spring.

NGT therefore designed and constructed a weir structure that can be actively and flexibly managed to retain water in the wetland for longer each year, using locally sourced hard ballast rock and wire baskets to form the geometry of the weir. The use of predominantly natural materials is also an important component of the restoration philosophy.

Now that the weir structure is in place the landholder is will install stock-proof fencing around the wetland perimeter, so that ground disturbance is reduced and to promote native vegetation regeneration associated with the restored water regime, to improve habitat conditions for native wildlife like Brolgas.

The reinstatement of hydrological regimes is an integral component of restoring wetland systems.  More imagery from this site will be provided after winter rains, later in the year.

This Case Study is the second in a series to illustrate wetland restoration in practice, delivered through Nature Glenelg Trust’s Wetland Restoration Program on Private Land and funded by the Australian Government.

Image I. Showing existing drainage channel, adjacent to the low lying wetland area.

Image II. Excavating the base for the weir structure. Note the existing drainage channel in the background.

Image III. Working to form the geometry of the weir. Local basalt rock was used to fill the wire gabiums and form the weir shape.

Image IV. NGT Project officer Dan Anderson stands at the regulation gate of the finished weir.

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