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The Victorian Environmental Water Holder (VEWH) has requested an amendment to the Tarago and Bunyip Rivers Environmental Entitlement 2009, under section 48K of the Water Act 1989.
This amendment is to enable VEWH to store its share of inflows in unused airspace in Tarago Reservoir, when its own capacity share is full - when VEWH’s share is in excess of its existing 3,000 Megalitre (ML) share of storage capacity in Tarago reservoir).
This amendment will enable VEWH to store its share of inflows in unused airspace in Tarago Reservoir, when its own capacity share (3,000 ML) is full. To ensure no impact to other entitlement holders, when Tarago Reservoir spills exceeds its maximum operating capacity), the amendment will also require that water held by VEWH in unused airspace is the first to spill.
This will formalise a temporary agreement to utilise unused airspace which has been in place since 2012 with Melbourne Water, Southern Rural Water and the Greater Yarra System – Thomson River Pool bulk entitlement holders, allowing VEWH more flexibility in managing its water holdings, and providing greater benefits for the environment.
More information about the application for an amendment
What is an environmental entitlement?
An environmental entitlement is an entitlement held by VEWH to take, apply or store water up to a maximum volume allocated under section 48B of the Water Act, subject to certain conditions and obligations.
An environmental entitlement is a legal right to take and use water granted under the Water Act for the purpose of maintaining an Environmental Water Reserve or improving the environmental values and health of the water ecosystems and other users that depend on environmental condition Environmental entitlements make it possible to actively manage water to meet specific environmental needs such as fish spawning triggers or maintaining critical habitats during drought.
The Tarago and Bunyip Rivers Environmental Entitlement 2009 currently entitles VEWH to:
- 3,000 ML share of storage capacity in Tarago Reservoir
- 10.3% of the net inflow to Tarago Reservoir (once passing flows have been delivered)
Inflows attributed to VEWH can be stored within the storage capacity specified in the environmental entitlement.
What has the Victorian Environmental Water Holder requested?
The storage capacity of Tarago Reservoir is shared between VEWH (3,000 ML) under its Tarago Bunyip Rivers Environmental Entitlement 2009 and Melbourne Water, under its Bulk Entitlement (Tarago and Bunyip Rivers - Melbourne Water) Order 2014.
Under section 48K of the Act VEWH has applied to the Minister for Water to amend the Tarago and Bunyip Rivers Environmental Entitlement, to enable VEWH to store additional inflows, above its 3,000 ML storage capacity, within unused airspace in Tarago Reservoir. Unused airspace refers to available storage capacity in the Reservoir that is not currently being used by an entitlement holder to store inflows.
This will formalise temporary arrangements which have been in place since 2012. These temporary arrangements have been providing a benefit to the environment since that time.
What were the temporary arrangements for VEWH’s access to unused airspace?
This amendment will formalise a temporary arrangement to utilise unused airspace which has been in place since 2012, and agreed to by Melbourne Water, Southern Rural Water and the Greater Yarra System – Thomson River Pool bulk entitlement holders.
These temporary arrangements have provided benefits to the environment with no negative impacts on other entitlement holders, and this amendment will mean these benefits can continue.
How will this amendment provide a benefit the environment?
This amendment will mean that VEWH can continue to access more environmental water than it would have otherwise. Without access to unused airspace, inflows that would have been attributed to the VEWH in excess of the 3,000 ML which could be store in VEWH’s storage capacity share would potentially have been lost (if not used immediately) and not be available for use by VEWH when it was really needed.
Water accrued in unused airspace as part of the temporary arrangements has contributed to a number of watering actions:
- Delivery of a spring high-flow event in September 2020 which improved water quality and provided opportunities for the upstream migration of juvenile native fish. It was the first time since 2012-13 that sufficient water for the environment was available to prioritise a spring high flow event in the Tarago River. Without the accrual of water in airspace, VEWH would not have had sufficient water to deliver this event.
- Accrued water has also been used for summer fresh events in 2014, 2015, 2016 and 2021 to help maintain water quality (dissolved oxygen) in times of low flow and allow for localised movement of native fish species.
How does this amendment ensure no impact to other entitlement holders/water users?
The proposed amendment will not have a negative impact on other water users because any water stored by VEWH in unused airspace is first to spill and therefore it does not prevent other entitlement holders using their full storge capacity.
It won’t reduce the volume of internal spills to Melbourne Water, because if VEWH did not have the ability to use unused airspace, the environmental water which could not be stored would be used in such a way to minimise the risk of internal spills from the environment’s share. Although this water would provide some benefits for the environment, benefits would not be optimised as the water could not be stored for later use when it was really needed.
How does VEWH plan the use of environmental water?
VEWH works with the relevant Waterway Manager (usually the local Catchment Management Authority but for the Tarago system this is Melbourne Water) to plan how environmental water is used each season. Each year a seasonal watering proposal is prepared by the waterway manager and these are informed by community consultation, including consultation with local Traditional Owner groups, and consider local conditions. These proposals then inform the Seasonal Watering Plan prepared by VEWH each year, which outlines how environmental water is used to get the most benefit.
Will this change impact the Victorian Government’s commitment to open Tarago Reservoir to on-water recreation?
No, the proposed amendments to the VEWH’s environmental entitlement is separate to this and will have no impact on the delivery of the commitment to open Tarago Reservoir to on-water recreation.
This amendment will formalise the temporary arrangement which has been in place since 2012.
Does this amendment impact flood risk or Melbourne Water’s ability to use Tarago Reservoir to mitigate floods?
The amendment will formalise the arrangements that have been in place since 2012 for storing water for the environment in Tarago Reservoir. As the amendment will not change how Tarago Reservoir is currently operated, it will not impact flood risk or Melbourne Water’s ability to use Tarago Reservoir to mitigate floods. Tarago Reservoir reaches its full capacity in most years, with spills occurring in 7 of the past 10 years.
The primary purpose of Tarago Reservoir is to provide a secure and safe water supply for the community – drinking water, irrigation, and for the environment. However, even when full, Tarago Reservoir provides some flood benefit by attenuating flood flows and reducing downstream flood peaks.
The Minister for Water will consider the request from the VEWH, upholding the requirements of the Water Act. Subject to the Minister for Water’s approval, the environmental entitlement amendment will come into effect when published in the Victorian Government Gazette.
More information and submissions
The Minister will consider any comments received from the public on the application. Written comments can be emailed to firstname.lastname@example.org or mailed to:
Executive Director, Water Resources Strategy
Department of Energy, Environment and Climate Action
PO Box 500
East Melbourne VIC 3002
By 16 November 2023
Page last updated: 22/11/23