Wetland Restoration on Private Land Case Study 1: Heywood District

This wetland restoration project involved the construction of an earthen weir and the fencing out of a wetland area within a grazing property near Heywood, to aid ecological restoration of the wetland system. The installation of an earth weir embankment has been designed to restrict artificial drainage outflows from a small wetland within this landscape.

The earthen weir, designed by Dan Anderson from Nature Glenelg Trust and constructed by local earthworks contractors (Farmers Field Services), was installed within an existing drainage channel on the property on Wednesday 19th June 2013. The weir structure has been designed to enable the re-hydration of a 2.4 ha wetland site by restricting the drainage outflow elevation by up to 80 cm within the existing drainage channel, thereby increasing the depth and duration of seasonal inundation. In the right situations, where adjustable water level regulation is not required, earthen weirs can provide a cost-effective wetland restoration solution.

The reinstatement of hydrological (water) regimes is an integral component of restoring wetland systems.

Additional imagery from this site has now been provided to show the impact of winter rains  at the site – see below.

This Case Study is the first 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. The use of clay materials acquired from the site to cap and line the triangular earth weir. Impervious clay materials reduce erosion and restrict infiltration to help retain the integrity of the embankment and encourage surface water movement over the crest.

Image III. The embankment completed with rock ballast capping, looking back toward the wetland depression. Note that the drainage channel remains as the relief point for all flow discharge. This ensures that the current preferential drainage pattern is not impacted by the works.

Image IV. Revisiting the same site in August 2013. Although the wetland has not yet reached the spill-over height at the relief point, the wetland restoration impact is already quite evident and dramatic.

Image V. Landscape view of the restored wetland, showing the now regulated artificial drainage outflow on the right hand side.

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