- The Barmah Choke is a narrow section of the Murray River that runs through the Barmah–Millewa Forest.
- The Choke has a trade restriction to protect delivery to existing entitlement holders and to maintain the river environment in the Choke.
- When water goes through the forest most of it makes its way back into the river again downstream of the Choke.
The Barmah Choke is a naturally occurring narrow stretch of the River Murray that begins downstream of Cobram, Victoria and ends upstream of Echuca, Victoria. The Choke runs through the Barmah–Millewa Forest on the Victorian/New South Wales border.
The Choke restricts the flow of the River Murray to just around 7,000 ML per day. This is the lowest flow in any stretch of the River Murray. It presents a challenge for river management, primarily because it limits the delivery of irrigation water during periods of peak demand, generally in spring and summer.
A default trade restriction is in place at the Choke, this is necessary to protect water delivery to existing entitlement holders and for environmental reasons. The restriction means that trade downstream of the Choke may only occur when there is sufficient matching trade capacity available in the opposite direction which is called ‘back trade’. Factors that influence the restriction include water availability and allocations, and high demand due to climatic conditions. More information on these factors is available in the River Murray annual operating plan. The restriction is governed by Schedule D of the Murray–Darling Basin Agreement through the Permissible Transfers between Trading Zones (Permissible Transfers) Protocol. We are responsible for keeping track of the balance of trade when the restriction activity is in place.
Trade from above the Barmah Choke to below the Choke is restricted to protect delivery of water downstream. This means people upstream of the Choke can sell water to buyers downstream of the Choke, but only if the same or greater volume of water has been transferred from downstream to upstream of the Choke first. We will continue to monitor the situation and will lift or adjust the restriction if conditions permit.
Read more detailed information about the Barmah Choke.
Background
At the end of each water trading year (30 June), under normal operations, the balance available for trading from above to below the Choke is cleared. Then, at the beginning of next water trading year (1 July), a volume is credited to the Choke balance. This annual adjustment takes into account water savings downstream of the Choke which are transferred to the Snowy scheme. This initial volume is available to be traded from above to below the Barmah Choke.
The opening balance for the following water trading year is usually announced by the MDBA in May. An example of how the Choke opening balance is calculated is available here.
More background information about the Snowy adjustment scheme can be found on this New South Wales Government website.
From 1 July 2019, the balance will be:
- increased by allocation trades from below to above the Choke
- increased by any deliveries against tags established from below to above the Choke
- decreased by allocation trades from above to below the Choke.
Further information about this legislative requirement can be found in the Murray–Darling Basin Agreement (Schedule D – Permissible Transfers between Trading Zones) Protocol 2010. Further information is available on the calculation of the Choke opening balance.
Through the millennium drought the trade restriction was relaxed, and trade occurred freely from above to below the Barmah Choke. On Tuesday, 28 October 2014, trade from above the Barmah Choke reverted to the default position and the restriction was actively applied.
