Wall of Somerset Dam
Location of the Somerset Dam in Queensland
|Location||South East Queensland|
|Dam and spillways|
|Type of dam||Gravity dam|
|Height||50 m (160 ft)|
|Length||305 m (1,001 ft)|
|Width (base)||41 m (135 ft)|
|Dam volume||203×103 m3 (7.2×106 cu ft)|
|Spillway capacity||4,650 m3/s (164,000 cu ft/s)|
|Total capacity||904,000 ML (199×109 imp gal; 239×109 US gal)|
|Active capacity||380,000 ML (84×109 imp gal; 100×109 US gal)|
|Inactive capacity||524,000 ML (115×109 imp gal; 138×109 US gal)|
|Catchment area||1,330 km2 (510 sq mi)|
|Surface area||4,350 ha (10,700 acres)|
|Max. length||52 m (171 ft)|
|Max. width||7 m (23 ft)|
|Normal elevation||108 m (354 ft) AHD|
|Installed capacity||3.2 MW (4,300 hp)|
|Annual generation||12 GWh (43 TJ)|
The Somerset Dam is a mass concrete gravity dam with a gated spillway across the Stanley River that is located in the South East region of Queensland, Australia. The main purpose of the dam is the supply of potable water for the Brisbane, Gold Coast and Logan City regions. Additionally, the dam provides for flood mitigation, recreation and for the generation of hydroelectricity. The impounded reservoir is called the Lake Somerset.
The dam, lake and surrounding village of Somerset are named in honour of Henry Plantagenet Somerset, a local grazier and Member of the Legislative Assembly of Queensland who represented the seat of Stanley from 1904 until 1920.
Location and features
The concrete dam structure is 50 metres (160 ft) high and 305 metres (1,001 ft) long. The 203-thousand-cubic-metre (7.2×106 cu ft) dam wall holds back the 904,000-megalitre (199×109 imp gal; 239×109 US gal) reservoir when at full capacity. However, only 380,000 megalitres (84×109 imp gal; 100×109 US gal) is used for water supply and the remainder used for flood mitigation. From a catchment area of 1,330 square kilometres (510 sq mi) that includes much of the western slopes of the D'Aguilar National Park, the dam creates Lake Somerset at an elevation of 108 m (354 ft) above sea level, with a surface area of 4,350 hectares (10,700 acres). The gated spillway has a discharge capacity of 4,650 cubic metres per second (164,000 cu ft/s). Built under the supervision of the Bureau of Industry, management of the dam was transferred to SEQ Water in July 2008 as part of a water security project in the South East Queensland region, known as the South East Queensland Water Grid. A small 4 megawatts (5,400 hp) hydroelectric power station is located adjacent to the dam wall.
A water level of 90% is the optimum capacity for keeping evaporation rates to a minimum. Dam operators discharge water into the Wivenhoe Dam downstream to hold Somerset at this level when inflows are occurring.
The site was first suggested for the location of a dam by Henry Somerset, the owner of Caboonbah Homestead, after the 1893 Brisbane floods caused severe damage to Brisbane River valley residents downstream. A commission of enquiry recommended Stanley Gorge as the site for a dam in 1928, but it was not until 1933 that the Forgan Smith Labor Government adopted the reservoir's construction as a major job creation project to counter job losses caused by the Great Depression.
Construction began in 1935. Worker's cottages had to be built and other facilities were constructed to attract 1,000 construction workers and their families to the area. By 1942 the dam was almost complete when workers were diverted to the war effort. Work on the dam recommenced in 1948. Opened in 1953 when structural work was finished, it was not until 1958 that the dam was officially named after Henry Somerset and the next year before all work related to the dam, including the hydroelectric power station was complete.
There are two public access areas on Somerset Dam, Kirkleigh and The Spit. Both locations have multi-lane, concrete boat ramps with facilities for day-trippers. Camping is permitted and caravans are catered for at Kirkleigh and below the dam wall at Somerset Park in the small town of Somerset Dam. During busy periods the two camping locations can be filled to capacity with room for a maximum of 2,200 campers at Kirkleigh and 800 at Somerset Park. The dam contains 30 kilometres (19 mi) of navigable waterway and a permit is required to use watercraft on the lake.
The lake is a popular fishing destination, one of the top five fishing spots in the state. Fish species found in the dam include Australian bass, golden perch, silver perch, bony bream, eel-tailed catfish, spangled perch, Mary River cod, snub nosed gar, Queensland lungfish and saratoga. A stocked impoundment permit is required to fish in the dam.
- "Register of Large Dams in Australia" (Excel (requires download)). Dams information. Australian National Committee on Large Dams. 2010. Retrieved 4 July 2014.
- "About". Somerset Dam, Queensland. Retrieved 7 July 2014.
- "Somerset Dam". Dams and weirs. SEQ Water. Retrieved 7 July 2014.
- Hurst, Daniel (7 July 2009). "Water funds slash debt". The Bayside Bulletin. Retrieved 21 April 2008.
- Williams, Brian (4 April 2009). "Somerset Dam water released as deluge delivers supply bonus". The Courier Mail. Queensland. Retrieved 24 April 2008.
- Heritage Trails of the Great South East. Environmental Protection Agency (Queensland). The State of Queensland. 2000. pp. 49–50. ISBN 0-7345-1008-X.
- "SEQWater - Dam Construction". SEQ Water. Archived from the original on 10 October 2007. Retrieved 11 May 2009.
- Harrison, Rod; James, Ernie; Sully, Chris; Classon, Bill; Eckermann, Joy (2008). Queensland Dams. Bayswater, Victoria: Australian Fishing Network. pp. 138–139. ISBN 978-1-86513-134-4.
- Maeseele, Melanie (8 April 2009). "Campers stream into full dam sites". Ipswich Queensland Times. Retrieved 29 April 2008.
- "Lake Somerset". Sweetwater Fishing Australia. Retrieved 7 July 2014.
- "Do I need a permit to go fishing in a dam?". Department of Agriculture, Fisheries and Forestry. Queensland Government. 5 February 2013. Retrieved 4 July 2014.
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