About the area
- The Millicent Coast basin spans parts of both Victoria and South Australia. The Victorian section of the basin comprises numerous internally draining wetlands located mainly in the south, and several minor waterways which flow intermittently and continue into South Australia.
- Groundwater is the most significant resource in the basin.
- The basin’s average annual rainfall ranges from below 400 mm in the north up to above 600 mm in the south.
More information on water management and accounting is detailed in Water .
2021-22 overview
Water used
More water was used for consumptive purposes than the previous year.
Climate
Rainfall
In 2021-22, rainfall in the Millicent Coast basin was close to average across the entire basin, higher than the previous year.
River basin water balance
Groundwater taken from the West Wimmera GMA is the main source of water supply in the Millicent Coast basin. Information about groundwater licences and use in this area is reported in the West Wimmera Groundwater .
Water balance table
Limited information is available for surface water availability and use, so a water balance has not been included for the Millicent Coast basin.
Storages
There are no major — greater than 1,000 ML — storages in the Millicent Coast basin.
Catchment inflow
There is no reliable streamflow data for the Millicent Coast basin. As such, an estimate of the volume of water leaving the basin was not made. As the Victorian Water Accounts estimate catchment inflow as a back-calculation from outflows, an assessment of the available water in the basin — catchment inflow — has not been made. Any surface water not diverted flows to South Australia.
Wastewater treatment plants
Water treated at wastewater treatment plants can be used to supplement water available in the basin.
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 Grampians Wimmera Mallee .
Small catchment dams
Water harvested, used and lost by small catchment dams (farm dams) is shown below.
Table 1: Small catchment dams, Millicent Coast basin
Entitlements and compliance
Entitlements basin provide the basis for how water is shared in the basin.
Entitlement volumes
Rights to water in the Millicent Coast basin are shown in table 2 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 2: Annual entitlement volumes at 30 June, Millicent Coast 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 209 ML taken under entitlements in 2021-22, about the same as the year before (246 ML).
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, about the same amount water was taken under entitlements as the previous year.
Table 3: Available water and take, Millicent Coast basin
Compliance
Compliance against water entitlements is reported for this basin in two 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.
Total entitlement volume
There was no net increase in the total entitlement volume from the previous year.
Total volume diverted
The total volume diverted (209 ML) was within the volume available for the year (5,075ML).
Water for the environment
Environmental watering sites
There are no environmental entitlements in the Millicent Coast basin, so no active environmental watering occurs.
However, the Millicent Coast basin contains numerous wetlands. The largest waterway in the basin, the ephemeral Mosquito Creek, provides streamflows to support Ramsar-listed wetlands in South Australia including Bool and Hacks Lagoons.
Environmental water reserve
In 2021-22, water for the environment in the Millicent Coast basin comprised all water in the basin not allocated for consumptive use: this water also provides social, recreational and cultural benefits.
Management responsibilities
Management of water in the Millicent Coast basin is undertaken by various parties
| Authority | Management responsibilities |
|---|---|
| GWMWater |
|
| Wimmera Catchment Management Authority |
|
| Glenelg Hopkins Catchment Management Authority |
|
