Review of impacts of system-wide drivers on Tar-ru

Option 3 examined the option to implementation of a risk-based framework for making decisions on the timings and source of water transfers to Tar-Ru (Lake Victoria).

Tar-Ru (Lake Victoria) is a naturally occurring shallow freshwater lake with a capacity of approximately 677 GL. It is located approximately 60 km downstream of the Murray– Darling Junction in south-western New South Wales, close to the South Australian and Victoria borders.

The lake is operated in accordance with formal operating rules designed to minimise shoreline erosion to protect Aboriginal cultural heritage sites. Tar-Ru can be filled from either unregulated River Murray flows or by transferring water from Lake Hume.

Filling the lake has historically been a challenge in dry years, but since the mid-2010s, filling the lake in late spring and meeting the minimum reserve level in May have become a more frequent challenge.

The below independent report is Stage 1 of the review into Tar-Ru operations and investigates the drivers for the variation in active storage whilst outflows have remained relatively constant since its operation as a regulated structure in 1928.

The key findings of this report show that reduced tributary inflows, operational constraints and efficiencies, demands for water, and limits on Tar-Ru water level changes have meant that more transfers of water from Lake Hume have been needed to fill Tar-Ru.