About the area
The Wimmera-Mallee groundwater catchment is in north-western Victoria.
The Wimmera-Mallee groundwater catchment contains the Murrayville groundwater management area (GMA). The area not covered by Murrayville GMA is reported as outside management units.
Groundwater resources within the catchment supply licensed entitlements, domestic and stock use, and urban use to Cowangie, Landsborough, Murrayville and Willaura, and they provide a backup urban supply for Horsham.
The Wimmera-Mallee groundwater catchment forms part of the Murray-Darling Basin, and groundwater management arrangements are subject to the requirements of the Murray-Darling Basin Plan.
The area that extends 20 km east from the border forms part of the Designated Area for the purposes of the 1985 Border Groundwaters Agreement between Victoria and South Australia.
Management responsibilities within the Designated Area are shared between Grampians Wimmera Mallee Water and the Government of South Australia.
More information on water management and accounting is detailed in Water explained.
2023-24 overview
Urban supply
Groundwater supplied to 4 towns in the catchment.
Water use
More water was used for consumptive purposes than the previous year.
Climate
Rainfall
Less rainfall was received in the Wimmera-Mallee groundwater catchment in 2023-24 than the previous year, being close to the long-term average across most of the entire catchment. Rainfall was:
- average in northern and central regions of the catchment, including Murray – Sunset National Park and Horsham
- below average near Murrayville, Warracknabeal and Dadswells Bridge
- very much below average in the south-east of the catchment around Halls Gap and Stawell
- the lowest recorded in the reference period (1975 to 2024) in the south-west of the catchment around Balmoral.
Figure 1 displays the rainfall received in 2023-24 compared to the long-term average (1975-2024).
Figure 1: Rainfall deciles, Wimmera-Mallee groundwater catchment
Sourced from the Australian Bureau of Meteorology
Groundwater level trends
In the Accounts, groundwater level trends for groundwater management units (GMUs) have been determined by monitoring data from key bores in the State Observation Bore Network. Trend determinations are made quarterly by comparing each reading to a previous reading in the same season 5 years prior; for example, a summer record is compared to the summer record from 5 years earlier to account for seasonality. These trends are shown in Table 1 below.
Groundwater resources are being actively managed. For more detail on management responses, go to on the Grampians Wimmera Mallee Water website.
In 2023-24, the groundwater level trend for the Murrayville GMA was stable towards the end of year.
Table 1: Groundwater level trends, Wimmera-Mallee groundwater catchment
Response to water availability
Groundwater restrictions
There were no restrictions on licensed groundwater use in 2023-24, the same as previous year.
Entitlements and use
Groundwater licence and use volumes in the Wimmera-Mallee groundwater catchment are shown below. Domestic and stock use does not require a licence, so in the Groundwater availability and take table (Table 3), these rows only report water taken.
The licensed volume used under entitlements must not exceed the volume made available to individual licensed entitlement holders. We report on compliance in the GMU local reports and in the Statewide groundwater summary.
Water used
Use in the Wimmera-Mallee groundwater catchment was 7,021 ML, more than the 6,030 ML used in the previous year.
Entitlement volumes
Rights to water in the Wimmera-Mallee groundwater catchment are shown below.
Table 2: Groundwater entitlements at 30 June, Wimmera-Mallee groundwater catchment
Available water and take
The table below shows the total water available and taken under entitlements, and estimated domestic and stock use in 2023-24. Total water available under entitlements is the sum of opening carryover, allocation issued and the net trade in or out of water.
Estimated domestic and stock use is calculated based on an assumed usage per registered bore per year. In this catchment, the assumed usage is 2 ML usage per bore per year.
More information on groundwater use and availability has been detailed in How we account for
In 2023-24, 7,021 ML of water was extracted for consumptive purposes, which was more than the 6,030 ML extracted in the previous year. Of this volume, 6,396 ML was for non-urban (irrigation) use, 309 ML was for urban use, and 316 ML was estimated to be for domestic and stock use.
Table 3: Groundwater availability and take, Wimmera-Mallee groundwater catchment
Management responsibilities
Management of water in the Wimmera-Mallee groundwater catchment is undertaken by various parties.
| Authority | Management responsibilities |
|---|---|
| Grampians Wimmera Mallee Water |
|
| Lower Murray Water |
|
| Government of Victoria / Government of South Australia |
|
