National Water Commission

The Hunter River is located within the South-East Coast Drainage Division in central New South Wales. Although the complete Hunter River catchment includes regulated and unregulated areas, only the regulated area was assessed for the water balance.

The Hunter River is a major coastal river that discharges to the ocean at Newcastle. It has several tributaries, including the Goulburn River, Williams River and Pages Creek. Lake Glenbawn, Glennies Creek Dam (Lake St Clair) and Lostock Dam are the major water storages within the regulated area and the major towns include Maitland, Muswellbrook and Singleton. The city of Newcastle is downstream of the regulated section of the Hunter River.

The Department of Natural Resources (DNR) is the licensing authority and manages both surface and groundwater diversions for urban, commercial/industrial, irrigation and environmental purposes. The Hunter – Central Rivers CMA is responsible for managing the native vegetation, soil and other natural resources in the catchment in conjunction with the community, local government, industry and State Government. State Water manages the major water supply storages in New South Wales and supplies bulk water to the irrigation authorities, town water supply authorities, mines, electricity generators and other industry by releasing water from its dams into rivers to be accessed by downstream water users. State Water also delivers water for private irrigators and stock and domestic users and is responsible for delivering environmental flows, in accordance with rules as set out in NSW Water Sharing Plans, on regulated rivers in the state.

Hunter Water operates in Newcastle and its surrounds treating and distributing drinking water as well as collecting and treating wastewater. In other areas of the catchment, the local council treats the bulk water and delivers it to urban users in the major towns within the catchment and also manage the wastewater collection and treatment network (e.g. Muswellbrook Shire Council. Both surface and groundwater resources are used for urban water supply in the Hunter River – Regulated WMA. Macquarie Generation own and operate two power stations in the catchment (Liddell and Bayswater) and is the major industrial consumer of water (for coal mining) in the catchment.



Figure 1 Hunter River - Regulated water management area locality map

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Rainfall across the Hunter River - Regulated WMA was above average in 2004-05, at around 113% of long term average rainfall; and over the last 10 years was 101% of the long term average (see Figure 2).

Allocations were at 100% in the Hunter Valley. The Lower Hunter received good rainfalls while drought conditions continued in the Upper Hunter corresponding to a higher use in the Upper Valley and lower use in the Lower Valley (State Water, 2006).

Table 2 Summary of the Hunter River – Regulated water management area contextual information

Figure 2 Annual rainfall for the Hunter River - Regulated water management area (modified from BOM, 2006)




Figure 3 Monthly rainfall and evaporation for the Hunter River - Regulated water management area (modified from BOM, 2006 & Climate Atlas)




Figure 4 Modelled pre development streamflow hydrograph for the Hunter River - Regulated water management area - the Hunter River at Glenbawn Dam (site 210097)




Figure 5 Modelled pre development streamflow hydrograph for the Hunter River - Regulated water management area – Glennies Creek at Glennies Dam (site 210117)




Figure 6 Representative bore hydrograph for the Hunter River - Regulated water management area (Bore name: Gnorang Dalswinto Rd Denman 1)

Summary of the total water resources in the basin

The total volumes of water available and supplied from water resources in the Hunter River – Regulated WMA are shown in Table 1.

Table 1 Summary of water balance in the Hunter River – Regulated water management area, 2004-05

Figure 7 Water balance summary diagram for Hunter River – Regulated water management area

Outcomes from the water cycle report

The following information becomes apparent from Table 2.

• The water balance was completed for the regulated area of the Hunter River catchment. There was a large amount of data available for the regulated area and the data quality for this water balance was relatively high. However, the balance may be misleading without considering the entire hydrological catchment (i.e. the combined regulated and unregulated areas). This is an opportunity for improvement in future assessments.
• The error in the water balance was 0%. This was due to the unaccounted for flows being incorporated with other items in the water balance. For surface water the balancing item was ‘Other losses’, the groundwater balancing item was the closing storage volume. Other jurisdictions reported unaccounted flows as an error term.
• The water balance was dominated by rainfall, diversions and outflows.
• Water use within the regulated area was predominantly for agriculture and power generation, however the catchment provides water to major urban users downstream (e.g. Newcastle).
• About 83% of water used in the regulated area was sourced from surface water in 2004-05, with the remainder from groundwater sources.
• The interaction between surface water and groundwater (predominantly seepage from streams to groundwater, although a significant volume is estimated to be baseflow) was 25,000ML in 2004-05, or 6% of the total captured rainfall (sum of runoff and recharge).
• There was about 11% less surface water available in storage at the end of 2004-05 than at the start, including the water stored in river channels. The major surface water storages had a 12% reduction in volume over the year, in real terms the storages started at 60% of capacity in July 2004 and finished at 53% of capacity in June 2005.
• The volume of groundwater stored was estimated by DNR by calculating the volume in the aquifer(s) to a depth of 20m below the ground surface (assuming a saturated thickness, estimating the water table drawdown depth from bore levels, and using the area and aquifer porosity). For the Hunter River – Regulated area, the volume of groundwater at the end of the year was determined from the volume at the start of the year plus any unaccounted for groundwater errors (i.e. it has been used as the balancing item).
• Data could not be obtained for the following items in the water balance:
• Minor catchment dams (may be a large part of the water balance).
• Soil - unsaturated zone storage volumes
• Urban treated effluent (returns to the river)

Download 2004-05 water cycle report: