South Australian River Murray irrigators have been advised to plan for low water availability with a minimum opening allocation of two per cent projected for the 2020-21 water year.
This is only a projected minimum opening allocation to help irrigators prepare for the year ahead, with the actual opening allocation to be advised on 15 June.
Irrigators will also be eligible to carryover unused allocation volumes available at the end of the current water year into 2020-21 (up to 20 per cent of their entitlement volume).
While irrigators will continue to be subject to a 100 per cent limit on their combined allocation and carryover volumes, new rules will be applied from 1 July 2020 that will improve the future flexibility of the carryover product for irrigators.
River Murray Water Delivery Manager with the Department for Environment and Water (DEW) Jarrod Eaton said the projected opening allocation is a conservative starting point, which provides certainty to irrigators who have indicated a preference that allocations do not get reduced mid-way through a season.
“Due to continuing dry conditions across much of the Basin, water flowing into the River Murray System in 2019-20 has been about one-third of the long-term average,” Mr Eaton said.
“Current volume in Murray-Darling Basin Authority controlled storages (2,726 gigalitres (GL)) is well below the end of March figure from last year (3,282 GL), and significantly below the long-term average end of March figure (5,505 GL) and this is one the key factors in determining the minimum opening allocation.
“It’s therefore likely all basin states will receive much lower allocations of water at the start of the 2020-21 water year and this in turn will limit how much water the DEW can allocate to individual water entitlement holders in South Australia.”
Mr Eaton said the latest rainfall outlook from the Bureau of Meteorology is looking positive, which increases the prospects of improvements to water allocations as the year progresses.
“Improvements to water availability each year is strongly linked to inflows into storages, releases from the Snowy Hydro Scheme and operational requirements to run the River Murray and the storages,” he said.
“While recent rainfall in the Basin has been welcome, the inflow response in the Southern Basin has been relatively low. A sustained period of at least average rainfall will be required to sufficiently re-wet catchments, produce higher inflows and improve storage volumes.
“Recent inflows into the northern Basin and Menindee Lakes will not be sufficient to improve South Australia’s water availability. Under the current water sharing rules all of the water in Menindee Lakes remains a New South Wales asset unless the storage volume increases above 640 GL.”
Mr Eaton said water allocation projections are determined in accordance with the South Australian River Murray Water Allocation Plan.
“Projections are updated on a monthly basis until the start of the new water year. Once the new water year has commenced, updates are provided on a fortnightly basis based on advice provided by the Murray-Darling Basin Authority until such time as allocations reach 100 per cent (should they do so),” he said.