An update to the deductions from spillable water accounts was made as part of the July 1 seasonal determination assessment.
The risk of spill in the Campaspe system at 1 July 2024: 70%
This value represents the percentage of years that spills occur from GMW’s share of Lake Eppalock 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 Eppalock at 1 July 2024: 29,476 ML
Click here to find the current volumes in Campaspe system spillable water accounts.
Ranked historic inflow to Lake Eppalock: April - Jun
Description and Tabulation of the graphical content inflow to Lake Eppalock: April - June
A bar graph titled Ranked historic inflow to Lake Eppalock: April – June is on the page above. X axis label “% Probability of Exceedance” which spans 99% on the left to 1% on the right. Y axis label is “3 month inflow – units megalitres (ML)”. Significant highlighted data in the graph is the inflow for the April – June 2024 period is indicated by the red line: 288 ML.
Each % probability of exceedance is reported from 99% to 0%. The general nature of the information presented is inflow values of greater than 129 megalitres have a high probability of occurrence (i.e. > 90%). Less than 10% probability of inflows above 70,575 megalitres.
Tabulation of data from the image above of the graph
99% |
0 |
90% |
129 |
2024 |
288 |
80% |
1,283 |
70% |
2,540 |
60% |
4,202 |
50% |
6,792 |
40% |
12,423 |
30% |
21,747 |
20% |
29,194 |
10% |
70,575 |
1% |
172,535 |
Ranked Historic inflow to Lake Eppalock: July - December
Description and Tabulation of the graphical content inflow to Lake Eppalock: July - December
A bar graph titled Ranked historic inflow to Lake Eppalock: July – December is on the page above. X axis label “% Probability of Exceedance” which spans 99% on the left to 1% on the right. Y axis label is “3 month inflow – units megalitres (ML)”. Significant highlighted data in the graph is the difference between the full supply volume of Lake Eppalock and the volume at 1 July 2024 is indicated by the green line: 29,476 ML.
Each % probability of exceedance is reported from 99% to 1%. The general nature of the information presented is inflow values of greater than 12,000 megalitres have a high probability of occurrence (i.e. > 90%). Less than 10% probability of inflows above 322,000 megalitres.
Tabulation of data from the image above of the graph
99% |
485 |
90% |
12,079 |
80% |
26,672 |
Current airspace |
29,476 |
70% |
42,340 |
60% |
61,157 |
50% |
99,708 |
40% |
136,806 |
30% |
168,289 |
20% |
206,555 |
10% |
321,823 |
1% |
397,247 |
Notes for charts:
There are 133 years of historic inflow data available for Lake Eppalock (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 Eppalock for the period 1 April to 30 June in each of those 133 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 (2024).
The second chart displays the volume of inflow to Lake Eppalock for the period 1 July to 31 December in each of the 133 years of historic data. The volumes of inflow shown are ranked in order from lowest to highest. The volume difference at Lake Eppalock 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, the probability that inflows to Lake Eppalock from 1 April to 31 June will be greater than 20,000 ML in any given year is close to 30%.
Additional notes:
- The volumes in spillable water accounts can change due to seasonal determination increases.
- The information provided here for the Campaspe system does not take into consideration the storage sharing arrangements at Lake Eppalock between GMW and Coliban Water.
- Current year inflows are based on operational data.