About the area
The West Wimmera groundwater catchment is in the far west of Victoria. The Victoria-South Australia border forms the catchment’s western boundary.
The West Wimmera groundwater catchment is fully covered by the West Wimmera groundwater management area (GMA).
Groundwater resources within the catchment supply licensed entitlement, domestic and stock use, and urban use to Apsley, Harrow, Miram, Serviceton, Edenhope, Kiata, Goroke, Lillimur, Kaniva, and Nhill.
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 9 towns in the catchment.
Groundwater restrictions
The same as the previous year, 80% allocation for Neuarpur subzone 1.
Water use
More water was used for consumptive purposes than the previous year.
Climate
Rainfall
Less rainfall was received in the West Wimmera groundwater catchment in 2023-24 than the previous year, ranging from close to the long-term average to the lowest recorded in the reference period (1975 to 2024) across the catchment. Rainfall was:
- average in the northern and eastern parts of the catchment around Wyperfield National Park and Nhill
- below average in northern and central parts of the catchment around Big Desert State Forest, Little Desert National Park and Goroke
- very much below average in most southern portions of the catchment including Apsley and Edenhope
- the lowest recorded in the reference period (1975 to 2024) along part of the catchment’s southern border.
Figure 1 displays the rainfall received in 2023-24 compared to the long-term average (1975-2024).
Figure 1: Rainfall deciles, West Wimmera 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, groundwater level trends for the West Wimmera GMA and Neuarpur subzone 1 were stable and declining, respectively, towards the end of the year.
Table 1: Groundwater level trends, West Wimmera groundwater catchment
Response to water availability
Groundwater restrictions
In 2023-24, licence holders in the Neuarpur sub-zone 1 - a trading zone in the West Wimmera GMA - were restricted to 80% of their licence volume, the same as the previous year.
Entitlements and use
Groundwater licence and use volumes in the West Wimmera 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 West Wimmera groundwater catchment was 19,814 ML, more than the 13,052 ML used in the previous year.
Entitlement volumes
Rights to water in the West Wimmera groundwater catchment are shown below.
Table 2: Groundwater entitlements at 30 June, West Wimmera 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, 19,814 ML of water was extracted for consumptive purposes, which was more than the 13,052 ML extracted in the previous year. Of this volume, 18,401 ML was for non-urban (irrigation) use, 601 ML was for urban use, and 812 ML was estimated to be for domestic and stock use.
Table 3: Groundwater availability and take, West Wimmera groundwater catchment
Management responsibilities
Management of water in the West Wimmera groundwater catchment is undertaken by various parties.
| Authority | Management responsibilities |
|---|---|
| Grampians Wimmera Mallee Water |
|
| Government of Victoria / Government of South Australia |
|
