Murray Low-Reliability Water Share

The information below provides more detail on the current water budget in the Murray system, and helps explain why no seasonal determinations against low-reliability water shares have occurred.

Click here for general information on making seasonal determinations and conditions needed to make a low-reliability seasonal determination.

Murray Water Budget - 15 January 2015

We need enough water available in the budget for existing commitment before low-reliability seasonal determinations can be made. Inflows above the predicted minimums are needed, but in 2014 the example used in the graph, we had been getting less than the predicted minimums. 

Data Column 1 - The Water Available 4,478 GL

• Projected Inflows - In 2014 / 15 projected inflows were down because we couldnt be sure at the time of production that we would get full supplies from the Snowwy in 1205 / 16. Murray inflow forecasts were also reduced with knowledge of the recent drought. Togethe projected inflows are now ~500 GL lower than the last time we had a low-reliability allocation. This equates to projected inflows 1,328 GL.
• Goulburn IVT - 147 GL.
• Water in the dams - In January 2015 Victoria's share of Dartmouth is 100% full and its share of Hume is 71% full. However, Victoria had no water available in Menindee Lakes. While this was quite high storage levels, the resources were required to be utilised as tributary inflows and were not going to be able to contribute substantially to the volume required to ensure supplies are secured for the following season. This equated to 3,003 GL of water in dams or in transit.

Data Column 2 - The Water Dedicated to

• Storage, river and channel losses were 492 GL. This included water for storage, channel and river losses upstream of South Australia required for the rest of the current season.
• SA Flows were 413 GL. The water needed to supply entitlement and dilution water to South Australia.
• Barmah account and LIndsay flows were 220 GL.
• Unused Allocation was 1,213 GL. This included 100% allocations to high-reliability and the remaining violuime of water carried over after spillng 47 GL.
• Reserves for next year 3,148 GL was needed. This included the resources needed to cover river and channel losses, flows to South Australia and full allocations to high-reliability entitlements next year. These reserves need to be met from the water budget before low-reliability seasonal determinations can be made. In January 2015, 2,140 GL of the 3,148 GL needed had been set aside in the budget.

The Difference Between Columns 1 and 2

The sum of all the water available in column 1 in the graphic is lower than the sum of water that is dedicated already in column 2. This difference is the shortfall, ~1000 GL shortgall to low reliability allocations. 

If it were the reverse with available water being greater than dedicated water then this is what makes up a low-reliability allocation amount.

Murray System Inflows

The water available in the Murray water budget is significantly less than volume required to make a low-reliability water share seasonal determination for a few reasons:

• Total Murray inflows from July to December, which are shared with New South Wales, have been about 2,570 GL below average (see graph below). 

• Historically, the Snowy scheme provides over 500 GL per year to the Victorian Murray. While the Snowy has provided its full supplement to the Murray this season, Snowy storages are still recovering from the drought so there is no guarantee yet that the full amount can be supplied next year. We can't yet count on this full resource to support allocations to low-reliability entitlements.