About the area
- The Glenelg basin is in the far south-west of Victoria. It has three on-stream storages, the largest of which is Rocklands Reservoir.
- The Glenelg River has the longest estuary in Victoria, extending 75 km from where it flows into the sea at Nelson.
- The basin receives 400-900 mm annual rainfall on average, with The Grampians ranges in the north-east receiving the most.
More information on water management and accounting is detailed in Water .
2021-22 overview
Available water
Catchment inflow was lower than the previous year.
Licensed diversion restrictions
The same number of restrictions on licensed diversions as the previous year.
Water use
About the same amount of water was diverted for consumptive purposes than the previous year.
When compared to the previous year, in 2021-22:
- slightly less rainfall was received, catchment inflow was lower and storage levels were similar
- there were the same number of restrictions on licensed diversions from unregulated streams
- about the same amount of water was diverted from the basin for consumptive uses.
Climate
Rainfall
In 2021-22, rainfall in the Glenelg basin was average across the entire basin, less than the previous year.
River basin water balance
In 2021-22, 17,416 ML of water was diverted for consumptive uses: town, domestic and stock, irrigation and commercial supply. Similar to the 17,922 ML diverted in the previous year.
Water balance table
The table below shows the total volumes of water available and supplied from water resources in the Glenelg basin in 2021-22.
Table 1: Water balance, Glenelg basin
Storages
Major — greater than 1,000 ML — on-stream storages in the Glenelg basin are included in the water balance.
Storage levels
Storage levels in the Glenelg basin were 25% on 30 June 2022.
Higher than the previous year
Storage levels were 24% on 30 June 2021.
Table 2: Storage levels, Glenelg basin
Catchment inflow
Catchment inflow represents the volume of water flowing into the waterways of a basin. It is calculated to be the difference between the total outflows, the known inflows and the net change in storage volume.
Below average inflow received
Catchment inflow was 60% of the long-term average of 527,300 ML.
Less than the previous year
This is lower than the previous year (63% of the long-term average).
Wastewater treatment plants
Water treated at wastewater treatment plants can be used to supplement water available in the basin. Water discharged to waterways from treatment plants is included as an inflow to the water balance.
Information on treatment plants is now reported in the Water Supply local reports for the water corporation responsible for managing the plant.
In this basin, wastewater treatment plants are managed by Wannon .
Small catchment dams
Water harvested, used and lost by small catchment dams (farm dams) is included in the water balance.
Table 3: Small catchment dams, Glenelg basin
Entitlements and compliance
Entitlements provide the basis for how water is shared in the basin.
Under GWMWater’s Wimmera and Glenelg rivers bulk entitlement, the water corporation operates the Wimmera-Glenelg system headworks to supply water to recreational lakes, towns and customers connected to the Wimmera Mallee Pipeline. It includes 3,300 ML for the Glenelg Compensation Flow and 28,000 ML for use in the Wimmera basin from Wimmera storages. It also supplies entitlements held by Coliban Water, Wannon Water and the VEWH. The Wimmera and Glenelg Rivers Environmental Entitlement 2010 provides the VEWH with water from the Wimmera-Glenelg system headworks to provide environmental benefits in both the Wimmera and Glenelg basins.
The Wimmera-Glenelg system is unique because the headworks harvest water from both the Glenelg and Wimmera river systems, and the volumes supplied to entitlement holders cannot be disaggregated between the two basins. For the purposes of this report, these entitlements are presented in the Wimmera .
Entitlement volumes
Rights to water in the Glenelg basin are shown in table 4 below.
Entitlement volumes represent a maximum volume that can be taken in a one-year period. The volume available in a particular year is dependent on the rules for allocating water set out in the entitlement and the seasonal conditions in that year, which varies. The rules for allocating water under an entitlement can differ between entitlements and systems. This affects the ability and likelihood of water being taken in a particular year.
Table 4: Annual entitlement volumes at 30 June, Glenelg basin
Available water and take under entitlements
Total water available under entitlements represents the volume of water that was available to be taken by entitlement holders in 2021-22. The volume includes seasonal allocations and net trade into the basin.
Water taken
There was 1,839 ML taken under entitlements in 2021-22, less than the year before (2,279 ML).
Restrictions on licensed diversions from unregulated rivers
There were bans in place on the Crawford River between December 2021 and May 2022. There were also bans on the Grange Burn and Wannon River, reaching a peak of three restricted streams in January 2022; this is the same as in the previous year.
Available water and take table
This table shows the volume of available water and the volume taken under entitlements in 2021-22.
More information on available water and take has been detailed in the How do we account for surface section on the How do we account for water page.
In 2021-22, less water was taken under entitlements than the previous year.
Table 5: Available water and take, Glenelg basin
Compliance
Compliance against water entitlements is reported for this basin in three areas:
- entitlement issued: the volume of entitlements issued in a basin does not exceed formal caps, and has not increased without appropriate approvals
- water taken: the volume of water taken during the year does not exceed the volume considered to be available for consumptive and/or in-stream use during that year
- bulk entitlement provisions: holders of entitlements do not breach any provisions that are documented in their bulk entitlement orders.
Total entitlement volume
There was no net increase in the total entitlement volume from the previous year.
Total volume diverted
The total volume diverted (1,839 ML) was within the volume available for the year (8,601 ML).
Individual bulk entitlements
No individual bulk entitlement holder took more than the annual volume made available to them.
Exceptions to compliance
Individual bulk entitlement holders complied with all provisions in their entitlements.
Water for the environment
Environmental watering sites
Environmental watering sites and environmental values in the Glenelg basin that depend on water for the environment include:
- the lower Glenelg River, which is a heritage river and which rely on freshwater inputs from the Glenelg basin to function
- Glenelg spiny crayfish (listed as threatened under the Victorian Flora and Fauna Guarantee Act 1988)
- Yarra and Ewens pygmy perch (listed as vulnerable under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 and threatened under the Flora and Fauna Guarantee Act 1988)
- variegated pygmy perch (listed as vulnerable under the Environmental Protection and Biodiversity Conservation Act 1999 and threatened under the Flora and Fauna Guarantee Act 1988)
- the Wimmera bottlebrush (Melaleuca wimmerensis, formerly known as Callistemon wimmerensis), which has been recorded on the Glenelg River. This species is very dependent on flows and is listed as threatened under the Flora and Fauna Guarantee Act 1988 and as critically endangered under the Environmental Protection and Biodiversity Conservation Act 1999.
Environmental water reserve
In 2021-22, water for the environment in the Glenelg basin comprised:
- a share of water available under the Wimmera and Glenelg Rivers Environmental Entitlement 2010 which includes 40,560 ML of high-reliability entitlement; water available under this entitlement is shared with the Wimmera basin
- water set aside for the environment through the operation of passing flow conditions:
- on consumptive bulk entitlements held by GWMWater and Wannon Water
- as part of the environmental entitlement held by the VEWH
- on licensed diversions, particularly from the Crawford, Glenelg, Grange Burn and Wannon rivers
- all other water in the basin not allocated for consumptive uses: this water also provides social, recreational and cultural benefits.
Environmental water use
In 2021-22, a total of 15,087 ML of environmental water was used in the Glenelg basin. This was all delivered in-stream for the Glenelg River. This volume includes 5,287 ML of passing flows delivered in-stream in the Glenelg basin.
Management responsibilities
Management of water in the Glenelg basin is undertaken by various parties
| Authority | Management responsibilities |
|---|---|
| Southern Rural Water |
|
| GWMWater |
|
| Wannon Water |
|
| Glenelg Hopkins Catchment Management Authority |
|
| Water supply system | 2021-22 (ML) | 2020-21 (ML) |
|---|---|---|
| Konongwootong | 90 | 65 |
| Glenthompson system | 2 | 4 |
| Grampians system | 1,133 | 1,560 |
