National Water Commission

The Macquarie water management area (2,739 km²) is located in the north east of Tasmania near the east coast. The basin includes the Macquarie River with major tributaries being the Glen Morriston and Tin Dish Rivulets, and the Blackman, Elizabeth and Isis Rivers (DPIWE, 2005b). The two lakes, Lake Leake and Lake Tooms provide regulated flows in the Macquarie and Elizabeth Rivers. The Blackman Dam was recently constructed and was filled for the first time in October 2005. Most irrigation in the Macquarie WMA is self extracted, with the water supplied using releases from Lakes Leake and Tooms.

The Department of Primary Industries and Water is the licensing authority and manages both surface and groundwater diversions although as yet there is no licensing system for groundwater. Local councils are responsible for providing town water supply. Towns in the area are Campbell Town, Tunbridge, and Ross.



Figure 1 Macquarie water management area locality map

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Rainfall across the basin was below average in 2004-05, at around 72% of long term average rainfall (Table 1). The 10 year average was 91% of the long term average (Figure 2). There was no apparent seasonal bias in rainfall (Figure 3). Streamflows in the Macquarie River at Tooms River were 26% of long term average (Figure 4).

Whilst there were no restrictions in the Macquarie in 2004-05, the river was regulated by Lake Leake and Tooms Lake and this governed the volume of water available for diversion.

Table 1 Summary of Macquarie water management area contextual information

Figure 2 Annual rainfall for the Macquarie water management area (modified from BOM, 2006)




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




Figure 4 Streamflow hydrograph for the Macquarie water management area at the Macquarie River at Tooms River

Summary of the total water resources in the basin

The total volumes of water available and supplied from water resources in the Macquarie WMA are shown in Table 2.

Table 2 Summary of water balance in the Macquarie water management area 2004-05

Figure 5 Water balance summary diagram for the Macquarie water management area

Outcomes from the water cycle report

The following information becomes apparent from Table 2.

• The error in the water balance was 43%.
• The water balance was dominated by rainfall and outflows to other entities.
• Water use was predominantly from surface water resources.
• The interaction of surface water and groundwater was only 5% of captured rainfall; however, there was very little information on groundwater and this figure is considered to be incomplete.
• The volume of water in storage in minor dams was 19% of the surface water runoff. This indicates that the water that could be stored in minor dams would have an impact on water availability.
• Data could not be obtained for the following items in the water balance:
• Surface water storage volumes, the volumes quoted are the capacity of the storages
• Groundwater storage volumes (renewable and non-renewable) and water quality (saline or non-saline)
• Groundwater flows
• Soil - unsaturated zone storage volumes
• Snowpack
• River channels storage volumes

Download 2004-05 water cycle report: