The Toorale Water Infrastructure Project was established under a 2008 funding agreement between NSW and the Commonwealth Governments for the purchase of Toorale station from Clyde Agriculture.
The project involves the development of a design solution to modify the water infrastructure at Toorale to protect and maintain the values of Toorale National Park, while also enabling greater capacity to divert flow through the Warrego River to the Darling River, for environmental and cultural benefits.
Alluvium was engaged to initially deliver the Business Case which included the identification of ecological, social and cultural values, fish passage requirements, and water delivery requirements to be protected and/or enhanced through the project.
At the time of purchase, the Toorale property included infrastructure to enable the use of water entitlements held for both the Darling and Warrego Rivers to irrigate 2,064 hectares of cropped area from the Darling River and/or to divert water onto the Western Floodplain (of the Warrego River) to enhance pasture production.
Since its addition to the NSW reserve system, the now Commonwealth-held water is used to achieve environmental benefits both on and downstream of Toorale. Management of water entitlements held for Darling River flows is relatively straightforward. However, the infrastructure used to harvest water from the Warrego River is more complex and includes embankments constructed across the Warrego River to capture and divert flow. These embankments (referred to as dams) were initially installed in the 1880s and have been the subject of numerous modifications, failures, rebuilds and upgrades.
This was a complex and challenging design. We designed a number of spillways on the Warrego River, including the Boera and Booka Dam sites to effectively distribute flows to the floodplain and to manage water supply to adjoining landholders. Some dams were modified to store water for irrigation and some structures, such as 12 Mile Dam and Peebles dam were decommissioned/ breached to not impede flow through the site.
As appropriate the design included rock ramp fishways on the spillways and vertical gates to provide control discharge over spillway (and allow targeted watering of the Western Floodplain).
A new embankment at the Dicks Dam site was constructed and Western floodplain training embankment was designed to deliver a low-lying embankment that prevents water on the Western Floodplain from returning to the Warrego River. This structure includes a number of pipe regulators that can be opened and closed to allow controlled releases from the Western Floodplain to the Warrego River.