Fairbairn Dam

The Fairbairn Dam is an earth-filled embankment dam across the Nogoa River, located southwest of Emerald in Central Queensland, Australia. Constructed in 1972 for the primary purpose of irrigation, the impoundment created by the dam serves as one the major potable water supplies for the region and assists with some flood mitigation.[1] Lake Maraboon with an active capacity of 1,301,000 ML (2.86×10¹¹ imp gal; 3.44×10¹¹ US gal) was formed by damming of the Nogoa River, and, in 2008, was Queensland's second largest dam.[1] Its capacity is approximately three times larger than Sydney Harbour. Maraboon is the Aboriginal for "where the black ducks fly".[2]

Fairbairn Dam
Location of the dam wall in Queensland
Country	Australia
Location	southwest of Emerald, Central Queensland
Coordinates	23°39′00″S 148°03′56″E
Purpose	Irrigation, water supply, flood mitigation
Status	Operational
Construction began	1968
Opening date	December 1972
Operator(s)	SunWater
Dam and spillways
Type of dam	Embankment dam
Impounds	Nogoa River
Height	46 m (151 ft)
Length	823 m (2,700 ft)
Dam volume	5,249×10^3 m^3 (185.4×10^6 cu ft)
Spillway type	Uncontrolled
Spillway capacity	15,580 m^3/s (550,000 cu ft/s)
Reservoir
Creates	Lake Maraboon
Total capacity	2,289,129 ML (5.03538×10^11 imp gal; 6.04724×10^11 US gal)
Active capacity	1,301,000 ML (2.86×10^11 imp gal; 3.44×10^11 US gal)
Catchment area	16,320 km^2 (6,300 sq mi)
Surface area	15,000 ha (37,000 acres)
Maximum water depth	31.7 m (104 ft)
Normal elevation	204 m (669 ft) AHD

Location and features

Commenced in 1968, the dam was engineered by Snowy Mountains Hydro-Electric Authority and completed in December 1972 for the purposes of irrigation and water storage. Storage of water commenced in January 1972 and the dam filled and overflowed for the first time two years later.[3] The dam wall consists of a 5,249 thousand cubic metres (185.4×10⁶ cu ft) earthfill embankment 823 metres (2,700 ft) in length and 46 metres (151 ft) high. The reservoir has a catchment area of 16,320 square kilometres (6,300 sq mi) with an uncontrolled concrete spillway capable of discharging 15,580 cubic metres per second (550,000 cu ft/s). The reservoir has an active capacity of 1,301,000 ML (2.86×10¹¹ imp gal; 3.44×10¹¹ US gal) of water;[4][5] When the dam spills over it flows into the Nogoa River.

About 300 irrigators are supplied with water for cotton, citrus and other horticulture operations.[6] The dam is relatively shallow with large areas of standing timber. There are no boating restrictions and one concrete boat ramp.[7]

Water from the Fairbairn Dam is released down the Nogoa River to the Selma Weir for supply to the town of Emerald. Supplies are diverted by pipelines to the towns of Blackwater, Bluff, Tieri, Dysart and Middlemount. Water from the dam also supplies coal mining developments on the Bowen Basin.[3]

The dam and reservoir are operated by SunWater.

Water storage levels

In July 2003, cotton farmers who were reliant on the dam for irrigation had their water allocation cut by 75%.[8] In November 2006, the dam had reached its lowest level ever—just 14% of total capacity.[6] Over that summer low inflows and high evaporation rates had dropped levels to 12%.

On 18 January 2008 water in the reservoir overflowed the dam spillway[9] for the first time in 17 years, due to heavy local rain.[10] Within 48 hours, the water level was about 3.5 metres (11 ft) over the spillway level, or 156% of active capacity. The water level peaked at about 4.5 metres (15 ft) on 22 January 2008. Downstream 2,700 residents had to be evacuated due to flooding.[11] Seven days earlier, the lake was operating at 29% of full capacity.[12]

On 30 December 2010 during the 2010–11 Queensland floods, the Fairbairn Dam reached a peak of 2,289,129 ML (5.03538×10¹¹ imp gal; 6.04724×10¹¹ US gal), or 176% of active capacity, with a reservoir elevation of 209.81 metres (688.4 ft) AHD . Water was recorded at 5.58 metres (18.3 ft) above the spillway.[13]

Dam capacities in Australia are frequently compared with the capacity of Sydney Harbour which holds approximately 500,000 megalitres (1.1×10¹¹ imp gal; 1.3×10¹¹ US gal).[14] This would make the dam approximately 3 times the storage of Sydney Harbour in normal conditions and 4 times in extreme flood.

On 29 December 2019 the Fairbairn Dam was at 9.6% capacity,[15] the previous record low capacity was in December 2006 at 11.8%.[16] In December 2019 the Central Highlands Regional Council made the decision to stay on level 1 water restrictions whilst they were undertaking a review of their trigger levels for water restrictions. [17]

Fishing

The lake has been stocked with barramundi, Mary River cod, southern saratoga, bass and silver perch.[7] Eel-tailed catfish, spangled perch, red claw crayfish, sooty grunter and golden perch Georgia fish are additionally present. On the lake fishing is banned within 200 metres (660 ft) of the dam wall, while below the ban extends for 400 metres (1,300 ft).[7]

See also

• List of dams and reservoirs in Queensland

References

1. "Fairbairn Dam performed well during Emerald's major flood event" (Press release). SunWater. 4 February 2008. Retrieved 21 November 2015.
2. "Fairbairn Dam visitor info" (PDF). SunWater. SunWater. Retrieved 2 February 2017.
3. "Nogoa Mackenzie". Storage Schemes. SunWater. Retrieved 21 November 2015.
4. "Fairbairn Dam". Current Water Storage Information. SunWater. Archived from the original on 28 May 2010. Retrieved 18 February 2008.
5. "Register of Large Dams in Australia" (Excel (requires download)). Dams information. Australian National Committee on Large Dams. 2010. Retrieved 15 October 2015.
6. Thompson, Tuck (16 November 2006). "Fairbairn dry for irrigators". The Courier Mail. Queensland Newspapers. Retrieved 15 May 2009.
7. Harrison, Rod; Ernie James; Chris Sully; Bill Classon; Joy Eckermann (2008). Queensland Dams. Bayswater, Victoria: Australian Fishing Network. pp. 102–103. ISBN 978-1-86513-134-4.
8. "Cotton downturn to hit central highlands' economy". ABC News. Australian Broadcasting Corporation. 1 July 2003. Retrieved 15 May 2009.
9. Belonogoff, Annisa (23 January 2008). "Fairbairn Dam continues to spill" (photo). ABC News. Australia. Retrieved 21 November 2015.
10. "Drought-stricken Fairbairn Dam overflows". 19 January 2008. Retrieved 20 January 2008.
11. "Flood victims 'hung out to dry' by insurers". Brisbane Times. 3 May 2008. Retrieved 15 May 2009.
12. "Latest River Heights for Nogoa River at Fairbairn Dam". Australian Bureau of Meteorology. Australian Government.
13. "New record for Fairbairn Dam" (Press release). SunWater. 31 December 2010. Retrieved 21 November 2015.
14. "When dam size matters". Bureau of Meteorology. 25 October 2012. Archived from the original on 21 August 2019. Retrieved 21 August 2019.
15. "Sunwater Fairbairn Dam Water Level". Storage Levels Sunwater. Retrieved 28 December 2019.
16. "Fairbairn Dam water allocations impacted by record low level". Queensland Country Life. Retrieved 28 December 2019.
17. "Why water restrictions arent tighter in Emerald". CQ News.