Daly: Water stores
- Heavy rainfall in late-January 2018 contributed to high annual runoff across the region.
- Below-average rainfall during most of the typically wetter months of the year resulted in relatively low aquifer recharge and a drop in aquifer storage.
For a water balance on each of the region's water stores for the 2017–18 year scroll down this page or click on the links below:
Surface water store
| Description | Volume (ML) | |
| Opening surface water store | 14,608 | |
| add | Inflows | 11,705,003 |
| less | Outflows | 11,960,241 |
| add | Balancing item | 253,603 |
| Closing surface water store | 12,973 | |
- The volume of water in the region's rivers at 30 June is typically very low and changes little from year to year (see Climate and water).
- It is likely that the balancing item is primarily attributed to uncertainties associated with the runoff, which is estimated from a rainfall–runoff model (see Methods).
Surface water flows
Figure S2 Water inflows and outflows for the surface water store during the 2017–18 year
- The largest natural water flows in the region were runoff and outflow. Both were higher than average, largely due to the monsoon event in late January that caused a major flood in the Daly River (see Climate and water).
Figure S3 Surface water diversions during the 2017–18 year in the region's key water management
areas
- Total surface water diverted in the region was 9,068 ML, mostly from the Katherine River.
- 41% of the surface water diversions were associated with an allocation (3,699 ML); the remainder was made under statutory rights.
- 74% of the allocated diversions were for the urban system; 26% were supplied to licenced individual users.
- For a more detailed description of the water usage in the region, and the associated entitlements, see the Surface water rights note.
Groundwater store
| Description | Volume (ML) | |
| Opening groundwater store | – | |
| add | Inflows | 406,000 |
| less | Outflows | 880,896 |
| less | Change in groundwater store | (460,000) |
| add | Balancing item | 14,896 |
| Closing groundwater store | – | |
- The volume of groundwater in the region could not be quantified due to a lack of available data; however, the change in groundwater storage during the year was estimated from a groundwater model.
- It is likely that the balancing item is primarily attributed to uncertainties associated with the groundwater recharge and discharge, which are estimated from a groundwater model (see Methods).
Groundwater flows
Figure S4 Water inflows and outflows for the groundwater store during the 2017–18 year
- More than 90% of the total groundwater inflows are attributed to recharge: landscape. Recharge was lower than the discharge from the aquifers, which contributed to the annual decrease in aquifer storage this year.
- The largest water outflow was discharge: surface water, which made up more than 95% of the total groundwater outflows.
Figure S5 Groundwater extractions during the 2017–18 year in the region's key water management
areas
- Total groundwater extracted in the region was 38,896 ML, mostly from the Oolloo Dolostone and the Tindall Limestone (Katherine) water allocation plan areas.
- 89% of the groundwater extractions were associated with an allocation (34,436 ML); the remainder was made under statutory rights.
- 99% of the allocated extractions were supplied to licenced individual users; 1% were for the urban system.
- For a more detailed description of the water usage in the region, and the associated entitlements, see the Groundwater rights note.