Frequently asked questions

Below are the frequently asked questions for 1 July 2021 opening water allocations.

How are the opening water allocations determined in NSW regulated rivers?

Within NSW, the sharing of available water is undertaken in accordance with the priorities for water sharing set out in the Water Management Act 2000 and the respective statutory water sharing plans for water sources. For the NSW Murray, Murrumbidgee and Lower Darling Rivers, the department must also consider interstate water sharing agreements and/or Snowy Hydro Scheme operations.

While the process for determining water availability and announcing available water determinations (typically referred to as allocations) is relatively straight forward, catchment conditions, climate variability, seasonal circumstances and a number of operational considerations can influence the allocation outcome. Nevertheless, the basic approach is outlined below.

Immediately prior to the commencement of the new water year on 1 July, the department calculates the minimum assured volume of water that will be available for allocation within each water source during the coming year.

This includes:

  • how much water is available in the storages; plus
  • a minimum natural inflow into storages (based on the historical record at the time of the first water sharing plan – 2004 for many regulated river valleys); minus
  • the volume required to run the river, including end of system flows, transmission losses and evaporation losses; minus
  • other water sharing plan requirements, including storage reserves and credits to environmental water allowances; minus
  • existing commitments, such as water to meet on-going high priority commitments including conveyance accounts and general security carryover.

One of the biggest issues faced over the last couple of years of drought is the fact that some major storages have experienced new ‘drought-of-record’ inflows since 2004. In the southern valleys the Millennium drought remains the drought-of-record, but in many northern valleys the recent drought recorded inflows significantly less than the previous worst droughts. It means that the planned ‘minimum inflows’ to storages have been far less than anything ever seen.

Until determined otherwise, the expected minimal inflows for allocations are still based on the drought of record as at the commencement of the water sharing plans, which is 2004 in the southern Basin.

When allocating water, the department is required to first ensure, as far as practicable, that two years of critical requirements can be met, before allocating to lower priority (general security) licence categories.

Has rainfall across the state since early this year improved water availability and does this mean better water allocations?

Today’s opening water allocations for NSW licenced water users reflect continued recovery in available water resources across the state as a result of many areas receiving above average rainfall over the last six months or so. This has resulted in improved water security for towns and critical needs, as well as good levels of access for most general security water users.

All critical needs, including town supplies, are secure for 2021-22 and all regulated river valleys have received their usual full opening allocation for high security licences.

Most high priority licence categories cannot carryover water; they forfeit unused account balance each year. Therefore, opening water allocations are mostly about ensuring annual allocations are provided for all high priority entitlements including towns, domestic, stock and high security licence categories.

Commencing general security water availability for the new 2021-22 water year is very encouraging for most inland regions of the State and particularly for the coastal catchments which are mostly fully allocated for the coming year. Nevertheless, routine (typically monthly) resource assessments will be undertaken and allocation announcements made for general security water users to identify and distribute any resource improvements to water users as the year progresses.

Aquifer access licenses in two groundwater sources; the Great Artesian Basin Eastern Recharge and the Lower Murrumbidgee Deep have received a reduced allocation as required by their respective water sharing plans because their long-term average annual extraction limits (LTAAEL) have been exceeded.

All other groundwater users have received a full allocation, apart from those (typically alluvial aquifers) linked to a reduced surface water allocation.

Supplementary allocations for the Gwydir and Border Rivers have been reduced as a result of exceeding the LTAAEL. Assessment of LTAAEL compliance for surface water will be revised after floodplain harvesting licensing commences.

With continued water resource recovery and good soil moisture for winter cropping, water availability across the entire Murray-Darling Basin is much improved at the commencement of this water year.

If opening water allocations are less than 100%, will more water be allocated later?

As the year progresses, regular assessments of surface water availability are undertaken. Improvements from inflows to storages following rainfall, as well as less than forecast transmission losses, are continually monitored so that any possible increases to water availability can be promptly allocated.

Groundwater sources with reduced allocation will generally remain unchanged for the year to restore extraction to within sustainable limits. Allocations can continue to accrue if resources improve, up to maximum account limits set out in respective water sharing plans.

Why is the NSW Murray general security opening allocation low, while the Lower Darling has 100%?

Rainfall and inflows in the Northern Basin since early this year has seen inflows to the Menindee Lakes System for the first time in almost two years – this has seen the lakes storage rise to around 66% full, underpinning full allocations in the Lower Darling. This increase in storage volume will secure minimum flows and critical needs in the Lower Darling for more than 18 months.

With Menindee Lakes currently holding about 1,060 gigalitres (GL), the volume above 480 GL is accounted as Murray resource and shared with Victoria under the Murray Darling Basin Agreement. Therefore, any further increase in Menindee resources will contribute to NSW Murray resource improvement. In addition, improvements in major Murray storages, which are currently around 50-60% full, will boost early NSW Murray general security allocations.

What is the outlook for improved water availability this year?

Forecasts for likely wetter conditions over winter and spring, particularly July to October for many parts of the state, have given most water users optimism going into the new water year.

How have groundwater allocations been impacted this year as a result of the recent drought?

The severity and length of the recent drought saw an increased reliance on groundwater.

Aquifer access licenses in two groundwater sources; the Great Artesian Basin Eastern Recharge and Lower Murrumbidgee Deep have received a reduced allocation because their long-term sustainable extraction limits have been exceeded.

Some temporary restrictions in the Upper Lachlan Zone 1 have been extended to manage localised excessive drawdown of groundwater levels.

All other groundwater users have received a full allocation, apart from those (typically alluvial aquifers) linked to a reduced surface water allocation.

How do storages volumes in major rural dams compare to this time last year?

Total storage levels for WaterNSW operated dams are at about 11,240 gigalitres, which is around 64% of total active storage capacity.

The storage volume for major state-operated dams this time last year was approximately 35%.

This shows a major improvement, nearly 30%, in overall storage levels across the state compared with the same time last year, noting there are some variations from valley to valley, as reflected in this year’s opening water allocations.

What about allocations in the unregulated rivers?

Unregulated river access licences have all received their usual full allocations at the start of the water year. However, they can only access water when river flow conditions are met. The amount of account water that can be used each year depends on river levels and licence conditions.

Take is limited to specific river levels, including river levels below which pumping must cease to protect low river flows. Therefore, under dry (low flow) conditions, unregulated river water users cannot take water despite regardless of their account balance.

Why isn’t the new drought of record being used in regulated rivers in setting allocations?

The drought of record in the water sharing plan establishes the balance between allocating water for productive use and storing water for security. The two objectives are mutually exclusive. The decision to move to the new drought of record, that is, to take water out of productive use every year to set-aside more water for droughts, is a substantial one that requires careful assessment and consultation.

There could be alternative ways of improving drought security apart from setting aside more water and reducing the volumes allocated to water users every year, which could have material impact on regional economies and communities.

This decision can be informed by the current regional water strategy work, but needs a proper assessment and discussion with stakeholders before changing allocation policy.

Notwithstanding this, every effort is made by the government to ensure that towns do not run out of water. This can be, among other things, by placing tighter water restrictions on other water users, temporary drought works in rivers and financial support to assist towns to identify and develop alternate water supplies.