Murray, and not Gunbower, New South Wales, Australia
By WazzaAndWenches on 15-Apr-18. Waypoint GA11101

Taken directly from a 2010 Murray Darling Basin Authority publication...

The Living Murray

The Living Murray is one of Australia’s largest river restoration programs, a major step towards ensuring the Murray is a healthy working river into the future.

Six sites along the River Murray have been identified as priority icon sites, including Gunbower-KoondrookPerricoota Forests.

Under The Living Murray, a program of works is being developed at each of the icon sites to make sure that available environmental water is used efficiently and ecological benefits are maximised.

The Living Murray is a joint initiative funded by the New South Wales, Victoria, South Australian, Australian Capital Territory and the Commonwealth governments, coordinated by the Murray-Darling Basin Authority.

The Koondrook-Perricoota Forest

The Koondrook-Perricoota Forest covers approximately 32,000 ha and is part of the second-largest river red gum forest in Australia. Changed flow regimes due to river regulation and a drier climate have impacted on forest health, leaving up to 87 % of trees severely stressed or dead. Works planned within the forest aim to improve the management and timing of floodwaters, which is vital for colonial waterbird and native fish breeding as well as the health of the iconic river red gum.

A significant ‘natural’ forest flood occurs when flows at Torrumbarry Weir exceed approximately 30,000 ML/day. The length and frequency of floods of this magnitude has reduced since the regulation of the river. Predictions indicate that within 50 years, floods of this size might only occur as infrequently as once every 25 years. This would have a devastating effect on the health of the forest.

The Living Murray proposal for the Koondrook-Perricoota Forest will achieve significant inundation of the forest with flows of only 3,500-6,000 ML/day over normal requirements, and is planned to occur every 3 to 4 years if required (when water becomes available).

Planned Works

The Torrumbarry Weir provides an opportunity for water to be diverted into the upstream end of the Koondrook-Perricoota State Forest from where it can take a similar course to natural floodwaters through the forest. A 3.8 km channel (‘Torrumbarry Cutting’) and a regulator is proposed to divert water into the forest from above Torrumbarry Weir.

Escape regulators at Swan Lagoon (Toorangabby) will be needed to stop water short-circuiting back into the River Murray. These works will direct the water so it can flow into parts of the forest and wetlands in the most critical condition.

A levee around the downstream perimeter of the forest closer to Barham will protect adjoining properties from flooding. Regulators on the outflow points will enable control of flows leaving the forest so that downstream properties are protected from high flows. Structures within the forest will also allow water to be returned directly to the River Murray, delivering better water efficiency and flexibility.

The scheme will be operated to mimic a range of natural flood events, which might have seen large-scale flooding of the forest occurring every 3 to 4 years for around 100 days at a time. In the case of a natural flood event, the scheme will be managed for minimal impact on natural flows.

The Cache...

The cache has been placed near the junction of the Murray River and the new Torrumbarry Cutting. Standing near the cache and looking out it's a not clear which waterway is the river. One is the Murray, and one is not.

The terrain rating reflects the fact that heavy rain will make for a VERY slippery approach - one that will test out both driver and vehicle recovery skills.

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