The risk of spill in the Goulburn system at 1 July 2021: 30%.
This value represents the percentage of years that spills occur from Lake Eildon taking into account the current storage volume, storage releases, inflows and evaporation from the storage using the historic data available.
Note: 10% or lower is the threshold for a declaration that would return water quarantined in spillable water accounts to allocation bank accounts.
Volume needed to fill Lake Eildon at 1 July 2021: 1,387,179 ML
Click here to find the current volumes in Goulburn system spillable water accounts.
Inflow for the April – June 2021 period is indicated by the red line: 167,270 ML
The volume difference at Lake Eildon between full supply and the storage volume on 1 July is indicated by the green line: 1,387,179 ML.
Notes for charts:
There are 128 years of historic inflow data available for Lake Eildon (inflow data for the period before the construction of the dam are based on modeled inflows). The first chart displays the volume of inflow to Lake Eildon for the period 1 April to 30 June in each of those 128 years. The volumes of inflow shown are ranked in order from lowest to highest with the red line representing the volume of inflow recorded for the period in the current year (2021).
The second chart displays the volume of inflow to Lake Eildon for the period 1 July to 31 December in each of the 128 years of historic data. The volumes of inflow shown are ranked in order from lowest to highest. The volume difference at Lake Eildon between full supply and the storage volume on 1 July is indicated by the green line.
Probability of exceedance: Probability that the volume of inflow will be equal to or greater than a specified volume in any given year. For example, in the first chart above, the probability that inflows to Lake Eildon from 1 April to 30 June will be greater than 400,000 ML in any given year is ~15%.
Additional notes:
- The volumes in spillable water accounts can change due to seasonal determination increases, provided there has been no low risk of spill declaration made
- Operation to target filling arrangements at Lake Eildon could see reductions to spillable water accounts prior to the storage reaching the full supply level.
- Current year inflows are based on operational data.