DEECA

About the area

  • The Ovens basin is in north-east Victoria. It covers an area that extends from the Great Dividing Range in the south to the Murray River in the north, and it is bordered by the Broken basin in the west and the Kiewa basin in the east.

  • Generally, rainfall is greater in the high country of the south of the catchment than in the northern regions along the Murray. At 1,400 m elevation, a large proportion of the winter precipitation falls as snow. Much of the high ground is snow covered from June – October.

  • Most of the average annual precipitation occurs during winter; the climate is warm and dry during the summer months.

  • Agriculture is confined mostly to the central region and in the north-east, between Beechworth and Chiltern, where forest grazing, beef, wool and lamb production are important.

 More information on water management and accounting is detailed in Water explainedExternal Link .

2021-22 overview

Available water

Catchment inflow was higher than the previous year.

Licensed diversion restrictions

There were fewer restrictions on licensed diversions than the previous year.

Seasonal determinations

Ovens system High-reliability allocations opened at 100% (the same as the previous year)

Water use

A similar volume of water was diverted for consumptive purposes to the previous year.

When compared to the previous year, in 2021-22:

  • more rainfall was received and catchment inflow was higher

  • storage levels peaked at slightly lower levels

  • seasonal allocations reached the same level, with high-reliability entitlements reaching 100% allocation; spill allocation was also available during the year

  • there were fewer restrictions on licensed diversions from unregulated streams

  • a similar volume of water was diverted from the basin for consumptive uses.

Climate

Rainfall

In 2021-22, rainfall in the Ovens basin was above average in most areas, much higher than the year before. Rainfall was:

  • very much above average in the north-east and areas west of Wangaratta

  • average in the south-east in Hotham Heights and above average everywhere else.

River basin water balance

In 2021-22, 22,678 ML of water was diverted for consumptive uses: town, domestic and stock, irrigation and commercial supply. While the total diversion volume was similar to the 23,606 ML diverted in the previous year, the volume of licensed diversions for irrigation was 4,677 ML less than last year – offset by a 4,004 ML increase in the estimation of small catchment dam use volume.

Water balance table

The table below shows the total volumes of water available and supplied from water resources in the Ovens basin in 2021-22.

Table 1: Water balance, Ovens basin

Storages

Major — greater than 1,000 ML — on-stream storages in the Ovens basin are included in the water balance.

Storage levels

Storage levels were 76% in June 2022.

Levels consistent with previous year

In June 2021 storages were 77% full.

Table 2: Storage levels, Ovens 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.

The volume of water flowing out of the Ovens basin into the Murray River represented 98% of the Ovens basin’s catchment inflows.

Above average inflow

Catchment inflow was 114% of the long-term average of 1,729,300 ML.

More water than last year

This was higher than the previous year (64% 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 North East WaterExternal Link .

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, Ovens basin

Entitlements and compliance

Entitlements provide the basis for how water is shared in the basin.

Diversions under bulk entitlements are assessed against the Murray-Darling basin annual cap target for the Murray-Kiewa-Ovens valley. Details of this assessment are published annually in the MDBA’s cap register and annual water take report.

Since 2019/20, the diversions are also assessed against the annual permitted takes under the Murray-Darling Basin Plan Sustainable Diversion Limit (SDL) compliance reporting which are annually published in the MDBA’s SDL accounts register of take and the Inspector-General of Water Compliance’s SDL compliance statement.

Entitlement volumes

Rights to water in the Ovens 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, Ovens 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 available under entitlements

There was 63,308 ML made available under entitlements in 2021-22, similar to what was available the previous year (64,195 ML).

Water taken under entitlements

There was 15,119 ML taken under entitlements in 2021-22, less than the year before (18,404 ML).

Seasonal allocations

  • High-reliability entitlement allocations opened the water year at 100% (the same as the previous year). There are no low-reliability water shares in the Ovens system, however spill entitlement was available for use during the year.

Restrictions on licensed diversions from unregulated rivers

  • There was one Stage 3 roster imposed on Mile Creek in April 2022; all other streams were unrestricted for the year. The previous year saw more restrictions; there were total bans in place on a peak of seven streams by February 2021.

Available water and take table

This table shows the volume of available water and the volume taken under entitlements in 2021-22. Water taken under entitlements could be used for a variety of uses.

More information on available water and take has been detailed in the How do we account for surface waterExternal Link section on the How do we account for water page.

In 2021-22, less water was available and taken under entitlements than the previous year.

Table 5: Available water and take, Ovens 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 (15,119 ML) was within the volume available for the year (63,308 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 in the Ovens basin that depend on water for the environment include:

  • the lower Ovens River (which contains heritage and iconic reaches), which is an important environmental asset that depends on water in the Ovens basin

  • the lower Ovens wetlands including Mullimur Wetland, which support freshwater catfish, egrets, herons, cormorants, bitterns and treecreepers and a large variety of aquatic vegetation

  • the Buffalo River and King River, which are important sites for large fish species during their breeding cycle: trout cod are found as far up the King River as Whitfield

  • water from the Ovens basin also flows into the Murray basin, helping to maintain environmental assets in that basin.

Environmental water reserve

In 2021-22, water for the environment in the Ovens basin comprised:

  • water set aside for the environment and other downstream uses:

    • through the operation of passing flows conditions on consumptive bulk entitlements held by Goulburn-Murray Water in the regulated rivers

    • through the operation of passing flow conditions on licensed diversions, including those set out in the Upper Ovens River WSPA Water Management Plan

    • through flow-sharing arrangements set out in North East Water’s bulk entitlements in the unregulated rivers

  • 123 ML of high-reliability water shares held for the environment

  • 92 ML of water allocation donated to the VEWH for delivery in the Ovens system, which included 36 ML of water allocation transferred to the VEWH for environmental and cultural outcomes

  • 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, 215 ML of environmental water was delivered in-stream in the Ovens basin.

Management responsibilities

Management of water in the Ovens basin is undertaken by various parties

AuthorityManagement responsibilities
Goulburn-Murray Water
  • Supplies primary entitlements in the regulated Ovens and King systems.
  • Manages licensed diversions.
  • Operates Lake Buffalo and Lake William Hovell.
North East Water
  • Supplies towns including Wangaratta, Bright, Myrtleford, Beechworth and Chiltern.
North East Catchment Management Authority
  • Responsible for waterway and catchment management in the region bounded by the Murray River in the north, the Victorian Alps in the south, the New South Wales border in the east and the Warby Ranges in the west.