Risk of Spill Information for the Murray system

Thursday 10 August, 2017

The risk of spill in the Murray system at 10 August 2017: 63.4%

This value represents the percentage of years that spills occur from Victoria’s share of Lake Hume 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 Hume at the time of the assessment: 720,207 ML

Click here to find the current volumes in Murray system spillable water accounts.

Ranked historic unregulated inflow to Lake Hume 

 Inflow for the May - July 2017 period is indicated by the red line: 164,557 ML

Ranked historic unregulated inflow to Lake Hume 

The volume difference at Lake Hume between full supply and the storage volume at the time of assessment is indicated by the green line: 720,207 ML.

Notes for charts:

The inflows to Lake Hume are provided as a guide only with these inflows subject to state water sharing arrangements where inflows are shared 50:50 between Victoria and NSW.

There are 125 years of historic inflow data available for Lake Hume (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 Hume for the period 1 May to 31 July in each of those 125 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 (2017).

The second chart displays the volume of inflow to Lake Hume for the period 1 August to 31 December in each of the 125 years of historic data. The volumes of inflow shown are ranked in order from lowest to highest. The volume difference at Lake Hume between full supply and the storage volume on 1 August 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, the probability that inflows to Lake Hume from 1 May to 31 July will be greater than 500,000 ML in any given year is around 45%.

Additional notes:

  • The inflow information provided here for the Murray system does not take into consideration the State sharing arrangements for the Murray storages. Click here to find the status of Victorian shares of Murray storages via the MDBA website.
  • The volumes in spillable water accounts can change due to seasonal determination increases. Active airspace management at Lake Hume could see reductions to Murray spillable water accounts prior to the storage reaching 100% capacity.
  • Current year inflows are based on operational data.