Establish Monitoring Program for Darling Anabranch Contract MD187.80 - M/BUS/267
MDFRC Technical Report (Version 2.0)
The Great Anabranch of the Darling River (the Darling Anabranch) is an ancestral path of the Darling River, which extends c.450km south from its off take on the Darling River (c. 50km south of Menindee, NSW). The Darling Anabranch is a naturally ephemeral stream which under non-regulated conditions would only receive inflows when flows in the Darling River reach 10,000ML/day. In the intervening period between construction of the Menindee Lakes storage scheme (1960) and 2002, the Darling Anabranch received an annual replenishment flow of up to 50,000ML/year to supply the stock and domestic requirements of adjacent landholders. Of this, only ~3,000 ML was extracted for consumptive purposes. The Darling Anabranch Pipeline was completed in February 2007. One of the overarching objectives of the Darling Anabranch Project was to create a more natural wetting drying cycle. The expectation was that water saved through the construction and operation of the pipeline, could be utilised to generate an environmental flow of c. 60,000ML at a maximum rate of c. 2,000ML/day every 2 to 3 years on average (when water is available in Lake Cawndilla) that would result in an end-of-system flow (Wallace et al. 2007). However, it is considered that flows of this magnitude are not achievable due to constraints associated with the outlet regulator at Lake Cawndilla (maximum release ~1,800 ML/day). Flows into the Darling Anabranch are also possible from the Darling River during periods of moderate to high flow (>10,000ML/day). The ability to deliver environmental flows into the Darling Anabranch (and the delivery route) is dependant on the future management and availability of water in both the Darling River and the Menindee Lakes system.