About the area
- Major rivers in the Tambo basin include the Tambo, Timbarra and Nicholson, which flow into the Gippsland Lakes.
- Most of the basin receives 600-900 mm rainfall annually, with some higher rainfall in the upper basin.
- Most of the basin’s area is steep forested mountains. There is a small southern section of flat farmland and an area of farmland in the middle to upper reaches of the Tambo River valley.
More information on water management and accounting is detailed in Water .
2021-22 overview
Available water
Catchment inflow was much higher than the previous year.
Licensed diversion restrictions
There were no restrictions on licensed diversions.
Water use
More water was diverted for consumptive purposes than the previous year.
When compared to the previous year, in 2021-22:
- more rainfall was received and catchment inflow was much higher (the highest in more than 15 years)
- there was no change to restrictions on licensed diversions from unregulated streams
- more water was diverted from the basin for consumptive uses.
Climate
Rainfall
Rainfall in the Tambo basin was very much above average across the entire basin, higher than the previous year.
River basin water balance
In 2021-22, 2,539 ML of water was diverted for consumptive uses: town, domestic and stock (water captured in small catchment dams), irrigation and commercial supply. This was more than the 1,531 ML diverted in the previous year. The increase was mainly due to small catchment dams capturing more water in the wetter conditions.
Water balance table
The table below shows the total volumes of water available and supplied from water resources in the Tambo basin in 2021-22.
Table 1: Water balance, Tambo 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 and the known inflows.
Diversions in the Tambo basin are minor compared to the total water resource. Swifts Creek is the only town supplied by the Tambo basin, while larger towns (such as Lakes Entrance and Bruthen) are supplied by the Bairnsdale water system (sourcing water from the Mitchell basin). Overall, almost 100% of the basin inflows passed through to the Gippsland Lakes in 2021–22.
Above average inflow
Catchment inflow was 441% of the long-term average.
More water received than last year
This was much higher than the previous year (155% 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 East Gippsland .
Small catchment dams
Water harvested, used, and lost by small catchment dams (farm dams) is included in the water balance.
Table 2: Small catchment dams, Tambo basin
Entitlements and compliance
Entitlements provide the basis for how water is shared in the basin.
Entitlement volumes
Rights to water in the Tambo basin are shown in table 3 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 3: Annual entitlement volumes at 30 June, Tambo 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 carryover from the previous year, seasonal allocations and net trade into the basin.
Water taken
There was 615 ML taken under entitlements in 2021-22, about the same as the year before (529 ML).
Restrictions on licensed diversions from unregulated rivers
There were no restrictions on licensed diversions from unregulated streams in 2021-22; 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, about the same amount of water was taken under entitlements as the previous year.
Table 4: Available water and take, Tambo 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 (615 ML) was within the volume available for the year (5,739 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
There are no environmental entitlements in the Tambo basin, so no active environmental watering occurs.
However, important sites and environmental values in the Tambo basin that depend on water for the environment include:
- the Gippsland Lakes, which are listed as internationally significant wetlands under the Ramsar Convention and which partially rely on freshwater inputs from the Tambo basin to function ecologically
- populations of Australian grayling and black bream
- the Tambo River, which has an extensive estuary extending from The Cliffs (upstream of Swan Reach) to the Gippsland Lakes at Lake King; significant wetlands along the estuary reach of the river include the East Swamps (south of Sardine Flat Road), Lake King Wetlands and Russells Swamp
- the Nicholson River, which has an extensive estuary reach that extends from the Great Alpine Road bridge at Sarsfield to where the river enters the Gippsland Lakes at Jones Bay; there are several important wetlands on both sides of the river, the largest being Bosses Swamp and Nebbor Swamp.
Environmental water reserve
In 2021-22, water for the environment in the Tambo basin comprised:
- water set aside for the environment through the operation of passing flow conditions:
- consumptive bulk entitlements held by East Gippsland Water
- on licensed diversions
- all other water in the basin not allocated for consumptive uses: this water also provides social, recreational and cultural benefits.
Management responsibilities
Management of water in the Tambo basin is undertaken by various parties
| Authority | Management responsibilities |
|---|---|
| Southern Rural Water |
|
| East Gippsland Water |
|
| East Gippsland Catchment Management Authority |
|
| Water supply system | 2021-22 (ML) | 2020-21 (ML) |
|---|---|---|
| Swifts Creek | 16 | 22 |
