Googong Dam

Googong Dam
Googong Dam wall and reservoir, 2006
Location of the Googong Dam in New South Wales
Country	Australia
Location	Queanbeyan, New South Wales
Coordinates	35°24′54″S 149°15′04″E / 35.41500°S 149.25111°E / -35.41500; 149.25111
Purpose	Water supply
Status	Operational
Opening date	1979
Owner(s)	Commonwealth of Australia, [Icon Water] (manage)
Dam and spillways
Type of dam	Embankment dam
Impounds	Queanbeyan River
Height	66 m (217 ft)
Length	417 m (1,368 ft)
Elevation at crest	663 m (2,175 ft) AHD
Dam volume	818 m3 (28,900 cu ft)
Spillways	2
Spillway type	Converging chute
Spillway capacity	10,500 m3/s (370,000 cu ft/s)
Reservoir
Creates	Googong Reservoir
Total capacity	119,400 ML (2.63×1010 imp gal; 3.15×1010 US gal)
Catchment area	873 km2 (337 sq mi)
Surface area	696 ha (1,720 acres)

Googong Dam is a minor ungated earth and rock fill with clay core embankment dam with concrete chute spillway plus a nearby 13 metres (43 ft) high earthfill saddle embankment across the Queanbeyan River upstream of Queanbeyan in the Capital Country region of New South Wales, Australia. The dam's purpose includes water supply for Canberra and Queanbeyan. The impounded reservoir is called Googong Reservoir.

Googong Dam was created through enabling legislation enacted via the passage of the Canberra Water Supply (Goodong Dam) Act, 1974.^[1]

A green ban was briefly imposed by the Builders Labourers Federation for a few days until adequate assurances that marine life in Lake Burley Griffin would not be harmed.^[2]

Completed in 1979, the Googong Dam is a minor dam on the Queanbeyan River and Bradleys Creek and is located approximately 5 kilometres (3.1 mi) south of the city of Queanbeyan on the lower reaches of the river. The dam was built by Thiess based on designs developed by the Commonwealth Department of Construction; and is now managed by Icon Water.^[3][4][5]

The dam wall height is 66 metres (217 ft) and is 417 metres (1,368 ft) long. At 100% capacity the dam wall holds back 121,083 megalitres (4,276.0×10^⁶ cu ft) of water at 663 metres (2,175 ft) AHD. The surface area of Googong Reservoir is 696 hectares (1,720 acres) and the catchment area is 873 square kilometres (337 sq mi). The ungated concrete chute spillway is capable of discharging 10,500 cubic metres per second (370,000 cu ft/s).^[3][5] Successive flood events in 1978 and through the 1980s resulted in extensive erosion in the unlined section of the spillway chute, including a large erosion hole, up to 19 metres (62 ft) deep and 25 metres (82 ft) wide, in the upper part of the spillway chute. Staged remedial works were undertaken in the 1980s to protect the eroded structure. Remediation of spillway facilities occurred from 2006 through to 2010 that resulted in an increase in the capacity of the spillway, construction of walls in the spillway chute extension up to 17 metres (56 ft) high, and a range of other enhancements to meet extreme flood events.^[5][6]

In 2016, with more regular spillway overflows, the dam's managing authority Icon Water, installed a 240m floating safety barrier, with authorised vessel access gate, across the spillway, to improve safety for waterway users.

• List of dams and reservoirs in New South Wales

• "Murrumbidgee and Lake George catchments" (map). Office of Environment & Heritage. Government of New South Wales.
• "Interactive ACT water supply map". ACTEW Corporation. 2011. Archived from the original on 12 April 2015. Retrieved 18 April 2015.
• "Googong Foreshores: Map and Guide" (PDF brochure). ACT Parks, Conservation and Lands. ACT Territory & Municipal Services.^{[permanent dead link‍]}