National Water Account 2022

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Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Daly: Supporting information

Water assets

Surface water assets

• Total surface water asset volume in the Daly region at 30 June 2022 was 9 GL, all of which was held in rivers. 
• The volume of water in the region's storages (see Region description) could not be quantified, however, this volume is very small compared with the volume of water in rivers.

Groundwater assets

• The volume of water stored in the region's aquifers cannot be quantified, however, information on the total annual change in aquifer storage is available.

• Below average rainfall contributed to low groundwater recharge and an annual decrease in aquifer storage of 684 GL.
• This was the greatest annual decrease in aquifer storage for the region over the period of record.

Water liabilities

• Water liabilities in the Daly region refer to the volume of allocation remaining on licence entitlements at the end of the 2021-22 year.

• Most surface water and groundwater licences have a management year that ends of 30 June.
• The portion of water allocated that was not abstracted during the 2021-22 year was forfeited, with no allocation remaining (carryover) being carried over to the start of the 2022-23 year.
• A more detailed description of water allocations in the Daly region is given in the Water use section below.

Water flows

• Total water inflows into the Daly region was 5,971 GL, 50% less than last year.
• Surface water inflows contributed 5,686 GL (95%) of total water inflows, with runoff contributing to 80% of the total water inflows for the region.
• Runoff was 43% below average (based on modelled data from 1971 to 2021), reflecting the below-average rainfall across the region.
• Groundwater inflows contributed 285 GL (5%) of total water inflows, with recharge from landscape contributing to 96% of total groundwater inflows for the region.
• Total water outflows from the Daly region was 4,976 GL, 55% less than last year.
• Surface water outflows contributed 4,182 GL (84%) of total water outflows, with river outflow contributed to 80% of the total water outflows for the region.
• River outflows were 53% below average (based on modelled data from 1971 to 2021), reflecting the below average rainfall resulting in below average runoff across the region.
• Groundwater outflows contributed 795 GL (16%) of total water outflows, with discharge to surface water contributing to 94% of total groundwater outflows for the region.
• A more detailed breakdown of inflows and outflows is given in the Statement of Changes in Water Assets and Water Liabilities for the Daly region.

Water use

Consumptive use

• Water taken from surface water and groundwater resources for consumptive use was 60 GL, 19% more than last year.
• Total surface water diverted in the Daly region was 9,381 ML, around 4% more than last year, mostly from the Katherine River.
• Around 58% of the surface water was taken for other users, while urban users accounted for 27% of surface water taken. The remaining amount of surface water taken was by agriculture users (12%) and cultural users (3%).
• Total groundwater extracted in the Daly region was 51 GL, 22% more than last year, mostly from the Oolloo Dolostone and the Tindall Limestone water allocation plan areas.
• Around 88% of the groundwater extractions were for agriculture users. Other users made up 8% of the total groundwater extraction, while the remaining amount was split amongst the other categories (cultural users (2.2%), urban users (0.9%), industrial users (0.6%), and mining users (0.2%)).
• Groundwater extracted by cultural users more than doubled from the previous year.

Allocations and diversions

• In 2021-22, total surface water allocation was 14,441 ML, mostly from the Katherine River for town supply. This was an increase of 63% from the previous year.
• While there was a large increase in surface water allocation, surface water diversions in the Daly region only increased by 10% to 3,832 ML (27% of the allocated surface water).
• In 2018–19, surface water allocations were increased as a precautionary measure in case groundwater supply to Katherine was further limited by the presence of per- and poly-fluoroalkyl substances (PFAS) and more surface water was needed to meet the town's water supply requirements.

• In 2021-22, total groundwater allocation was 144 GL, mostly from the Oolloo Dolostone and Tindall Limestone aquifers for agricultural purposes.
• Groundwater extractions in the Daly region was 46 GL, 24% more than last year. This equates to 32% of groundwater allocations being taken.
• The below average rainfall most likely influenced the increase in groundwater extractions during the 2021-22 year.
• During the past four years, groundwater supply to the town of Katherine has been limited due to a requirement for groundwater to be filtered to remove per- and poly-fluoroalkyl substances (PFAS) before transfer to the urban system (see Water restrictions for more detail).

Water restrictions

• A per- and poly-fluoroalkyl substances (PFAS) treatment plant commenced operation in the region in October 2017 to remove higher levels of PFAS identified in the town of Katherine's groundwater supply. Groundwater extracted from the Tindall Limestone Aquifer was filtered to remove PFAS prior to transfer to the urban system.
• The PFAS removal process has meant that groundwater supply to the town of Katherine has been limited during the last three years. Although most of the town water supply for Katherine comes from surface water, the drop in groundwater contribution meant total water usage in Katherine needed to reduce by 20% to ensure a sustainable water supply.