Goulburn Low-Reliability Water Share

The information below provides more detail on the current water budget in the Goulburn 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.

Goulburn 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 3,330 GL

• Projected Inflows - Inflow forecasts have reduced with knowledge of the recent drought. Projected minimum inflows are now ~130 GL lower than a decade ago. This equates to projected inflows 568 GL.
• Other Sources - Includes trade from the Loddon and Campaspe. There is no water available in January 2015 from the Loddon supplement due to dry conditions in the Loddon. This equates to 29 GL.
• Water in the dams - In January 2015 Lake Eildon was around 75% full. Storage levels at Eildon increased from 68% to 87% over the winter and early spring in 2014, but continued to decrease as release rates were higher than the rate of inflow. This equated to 2,734 GL of water in dams.

Data Column 2 - The Water Dedicated to

• Storage, river and channel losses were 500 GL. This included 215 GL of dead storage, and losses required for the rest of the current season.
• Trade to the Murray was 147 GL. Water owed to the Murray in the inter-valley trade account
• Unused Allocation was 1098 GL. This included 100% allocations to high-reliability and 456 GL carried over.
• Reserves for next year 1,975GL was needed. This included the resources needed to cover river and channel losses 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, 1,585 GL of the 1,975 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, ~390 GL shortfall to low reliability allocations. 

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

Goulburn System Inflows

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

• Inflows this season from July to December have been 1,070 GL below the long-term average (see graph below). 

• Historically, the Loddon supplement also provides on average about 80 GL per year to the Goulburn system. However, over recent years our understanding of the reserves to run the Loddon River and secure allocations for Loddon diverters has changed, which has reduced the amount of water available for the Goulburn. There is no water available in the Loddon storages to supplement the Goulburn system this season.