Frequently asked questions

Below are the frequently asked questions for 1 July 2020 opening water allocations.

How is water shared and 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 decisions. 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 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 current drought has 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.

In the southern valleys, these high priority commitments have now largely been met, apart from a small deficit in the NSW Murray, meaning that further improvements over coming months can mostly be applied to general security allocation.

Another major issue has been the volume needed to run regulated rivers to deliver all water orders and entitlements, including to South Australia. The current drought has, in many river systems, exceeded historical records resulting in transmission and evaporation losses never before encountered.

In a nutshell, reduced inflows and increases losses across large parts of NSW reduced water availability in 2019-20 well beyond normal expectations.

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

While some parts of the state have received average or above average rainfall over the last 3 to 4 months, it hasn’t been what could be described as ‘drought breaking’. Unfortunately, a large portion of the rainfall has occurred downstream of major storages, meaning that most water has been unable to be captured for allocation.

The 1 July opening water allocations for NSW licensed water users reflect some recovery in areas that have experienced record drought, improved water security for towns and critical needs, but little improvement for most general security water users as the inflows to most storages, although welcomed, have not been substantial.

As a result of the inflows, all regulated river valleys, apart from the Peel, Lachlan and Hunter, have received their normal full opening allocation for high security licences.

Start of water year general security water allocations for all inland regions of the State are still low or zero - while the coastal catchments are generally better placed for the coming year.

However full access to carryover water in accounts will be available in all valleys, except the Macquarie and Lachlan Valleys where some restrictions are still in place.

Despite these low opening general security allocations, the real benefit from these sporadic rainfall events has seen the water deficits in most valleys erased – which means that further inflows are likely to provide better general security allocation.

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. Reduced allocations to unregulated river access licence holders in the Macquarie near Bathurst can be increased when Bathurst town water supply security improves.

Why is the NSW Murray general security opening allocation at zero, while the Lower Darling has 30%?

Rainfall in the Northern Basin since early this year has seen inflows to Menindee Lakes for the first time in almost 2 years – this has seen the lakes storage rise from 1% in February to around 29% full.

This increase in storage volume will secure minimum flows to the Lower Darling for the next 12 to 18 months. It also supports flows for stock and domestic use, a full allocation to all high priority entitlements plus a modest general security allocation.

However, the storage in Menindee Lakes is not sufficient to contribute to NSW Murray general security at this time. It is not until the Menindee system exceeds 640 gigalitres (GL), some 37% full, that it becomes a shared Murray resource under the Murray Darling Basin Agreement. Upstream rivers have now reduced to near baseflows meaning the system is unlikely to reach this trigger level in the foreseeable future.

There were a number of temporary water restrictions implemented during the last water year – will they continue this year?

While most valleys start the year free from temporary water restrictions, the Lachlan and Macquarie general security water users continue to have restricted access to water in their accounts as a result of very low water availability across these catchments.

Depending on further inflows to rivers and storages across the state in coming months – additional temporary water restrictions may again be necessary if conditions worsen in some water sources. Systems are managed adaptively through changing seasons and resource conditions, with allocations or conversely restrictions, applied as necessary.

Temporary water restrictions can be applied to localised groundwater sources to manage excessive water level drawdown and the resultant adverse impacts on access, dependent ecosystems and the aquifer itself.

What is the outlook for improved water availability this year?

The latest Bureau of Meteorology forecasts provide some cause for optimism. For many parts of the state the prediction is for likely wetter seasonal conditions over winter and spring, particularly August to October.

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

The severity and length of the drought has seen an increased reliance on groundwater.

Aquifer access licences in three groundwater sources - the Great Artesian Basin Eastern Recharge, Lower Murrumbidgee Deep, and Upper Namoi Zone 3, have received a reduced allocation because their long-term sustainable extraction limits 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.

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

While rainfall across various parts of the state since early 2020 has seen some improvement – much of this rainfall has been below the major dams. Although the rainfall has been replenishing soil moisture and providing good winter cropping conditions, there has been limited capture so far in storages.

The current storage volume for major state-operated dams is approximately 34% of total storage capacity. This time last year total storage capacity was approximately 31%.

This shows only a minor improvement is overall storage levels across the state, 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 rivers usually receive full allocations at the start of the water year. However they can only access water when river flow conditions are met. How much of their account water they can use each year depends on river flow conditions and their licence conditions relating to river flows at which they can commence to pump or must cease to pump.

However, the exception this year is those unregulated river systems that can affect Bathurst Council’s water supply. Concerns over town water supply security means that commercial water users in this area are restricted to a 20% allocation on 1 July.

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 which could have material impact on regional economies and communities.

This can be considered as part of the regional water strategies initiative but needs a proper assessment and discussion with stakeholders before changing allocations.

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