Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Overview - Queensland

Location map of St. George Alluvium

Groundwater Management Unit: St. George Alluvium

Introduction

The town of St George is located approximately 550km west of Brisbane. The St George Alluvial Groundwater Management Unit (GMU) is situated in the Balonne-Condamine River Catchment. The GMU falls over 4 sub-basins (4222, 4224, 4172 and 4225) and covers an area of approximately 23580 square kilometres. The GMU includes part of the Balonne, Booringa and Warroo Shires with St George being the principle town. Other towns include Hebel, Dirranbandi and Bollon. The Balonne, Culgoa, Narran and Maranoa Rivers are the major drainage systems in the GMU.

South of St George is the St George Irrigation Area, covering approximately 300 sq km. This defined area uses surface water, supplied from the E.J.Beardmore Dam, for the large-scale irrigation of cotton.

In the past, groundwater demands have been solely for stock and domestic purposes with surface water supplies from the dam storage and river flood harvesting meeting previous irrigation water demands. Sub-artesian resources are being developed and explored to cater for increases in water demand. Groundwater supplies are intended to supplement existing dry-land crops and meet water demands for stock grazing.

The sub-artesian resources of the St George GMA can be divided into two aquifer systems. Aquifer 1 is located in the deeper section of the basin in a trough trending north-north-east to south-south-west. Aquifer 2 is more laterally extensive within the boundary of the GMA. Aquifer 1 has more potential as a major source of water supply with yields of up to 120 l/s achievable from production bores. Groundwater yields of bores tapping into the shallow regional aquifer, Aquifer 1, are only useful for stock and domestic purposes.

In 1995, the potential for groundwater in the St George Alluvium was recognised. By the end of 1997, approximately 69 000 Ml of allocation was applied for under licenses. Initial allocations have been set so that irrigation can proceed. Private development of sub-artesian groundwater resources has commenced on some properties with an estimated 2 000 Ml abstracted from seven bores during 1997/1998.

The St George Alluvium GMU experiences a semi- arid climate. The annual rainfall varies from 550mm in the north-east to 350mm in the south- west with approximately 56% occurring between the months of November and March, inclusive.

Vital Statistics:

Area: 23,580 Km2
Total water allocated: no data
Total water consumed: 2,000 ML/yr
Average salinity: 2,915 mg/l
Sustainable yield: 18,000 ML/yr
Depth to top of aquifier: 36 m

Further Information

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