Paradise Dam (Queensland) Explained

Paradise Dam
Location Map:Australia Queensland
Location Map Size:280
Location Map Caption:Location of the dam wall in Queensland
Coordinates:-25.3511°N 151.9194°W
Country:Australia
Location:20km (10miles) northwest of Biggenden, Wide Bay-Burnett region, Queensland
Purpose:Irrigation
Status:O
Opening:2005
Cost:A$240 million
Owner:Burnett Water
Operator:Sunwater
Dam Type:Gravity dam; Roller-compacted concrete
Dam Crosses:Burnett River
Spillway Count:1
Spillway Type:Stepped spillway chute with a smooth ogee
Res Name:Paradise Dam
Res Capacity Total:300000ML
Res Catchment:33000ML
Res Max Depth:38.2m (125.3feet)
Res Elevation:67.6m (221.8feet)
Plant Name:Paradise Dam Mini Hydro
Plant Coordinates:-25.3511°N 151.9194°W
Plant Operator:SunWater
Plant Commission:2006
Plant Type:Conventional
Plant Turbines:1 X 2.7 MW Kaplan

The Paradise Dam, also known as the Burnett River Dam, is a roller compacted concrete (RCC) gravity dam across the Burnett River, located between Coringa and Good Night northwest of and southwest of in the Wide Bay-Burnett region of Queensland, Australia. Built for irrigation, the impoundment created by the dam is called Lake Paradise.[1] [2]

In September 2019, concerns about the structural stability of the dam resulted in the water levels in the dam being lowered to 42% of its maximum capacity. In 2020 a report found that the roller-compacted concrete was "intrinsically incapable" of achieving the required standard for safety.[3] In 2024, it was announced that the dam would be functionally replaced with an entirely new dam due to these concerns.[4]

Location and features

The concrete dam wall is up to high and spans approximately . The dam is named for the ghost town of Paradise, which is now under water following construction.[5] [6]

Approval to build the dam was given in 2002. It was constructed on behalf of the Queensland Government between 2003 and 2005. The dam is owned by a government-owned corporation, Burnett Water. Since construction was completed in December 2005, it has been operated by another Queensland government-owned corporation, Sunwater. Construction of the 300000ML capacity dam cost A$240 million to complete and was intended to assist the social and economic growth of the region.

The dam is also significant in that it has been the centre of a controversial fishway designed to allow movement of fish upstream and downstream of the dam wall, including the endangered Queensland lungfish.

When the Paradise Dam is full, water is released over a stepped spillway followed by a stilling basin. The spillway chute is wide with a smooth ogee profile, ending a few small steps leading to 1V:0.64Hstepped chute with a step height of . The chute is followed by a stilling basin before rejoining the natural river course.

Between 2010 and 2013, the spillway system passed four major events, thus mitigating the effects of flood in the downstream catchment including the city of Bundaberg. The peak discharges were experienced in December 2010, January 2011, January 2013 and in March 2013.

Fishways

An upstream fishway, known as the upstream fishlift, was installed on the dam for a cost of $12 million. It consists of a 7500L caged container known as the hopper that sits at the downstream base of the dam wall. When operating, water is passed through the hopper to attract fish into it. The hopper is lifted over the dam wall to release any fish that have entered the hopper into the reservoir. The hopper is then returned to the base of the dam and the cycle repeated.

A downstream fishway, known as the downstream fishlock, was installed on the dam for a cost of $8 million. It consists of an inlet chamber on the upstream side of the dam wall in the reservoir and a pipe to the downstream side of the dam. When operating, fish are attracted into the inlet chamber by flowing water.

The downstream fishway was not operated from the completion of the dam in December 2005 until February 2009 due to water levels in the dam being beneath the entrance of the fishway. Since the dam commenced operation, the upstream and downstream fishways have not operated for approximately 60% of the time due to a combination of low water levels, mechanical failure, and being shut-down. Operation of the fishway has been limited to only those time when there are low and medium flow releases.

SunWater, the state entity which manages the dam, released final fishway monitoring reports in 2012 for the upstream fishway[7] and the downstream fishway.[8] 25 species different species have been recorded successfully using the upstream fishway.[7]

No lungfish have been recorded using the downstream fishway and very few have been recorded using the upstream fishway. The monitoring indicates that large bodied fish (lungfish, barramundi, mullet, bass) are not using the fishways.

A conservation group unsuccessfully challenged the lack of operation of the fishways on the Paradise Dam in court proceedings in 2008–2010.[9] [10]

Structural concerns

In September 2019, concerns about the structural stability of the dam resulted in the water levels in the dam being lowered to 42% of its maximum capacity.

Construction started in May 2020 to lower the dam wall height by, CPB Contractors was selected as the contractor.

In 2020 a report found that the roller-compacted concrete was "intrinsically incapable" of achieving the required standard for safety.

In 2024, it was announced that the dam would be functionally replaced with an entirely new dam due to these concerns.

See also

External links

Notes and References

  1. 18 November 2015.
  2. Web site: September 2020. Paradise Dam Essential Works: Fact Sheet: Roller Compacted Concrete Sampling & Testing. 30 June 2021. SunWater. 9 July 2021. https://web.archive.org/web/20210709181344/https://www.sunwater.com.au/wp-content/uploads/Home/Projects/Paradise-Dam-Essential-works/Paradise_Dam_Roller_Compacted_Concrete_Fact_Sheet_September_2020.pdf. live.
  3. Web site: Marie. Johanna. 2020-05-21. Concrete in Paradise Dam wall may have failed design standard, inquiry finds. 2020-08-24. ABC News. en-AU. 20 July 2020. https://web.archive.org/web/20200720055831/https://www.abc.net.au/news/2020-05-21/concrete-in-paradise-dam-wall-fails-to-meet-design-standard/12272216. live.
  4. News: Marie . Johanna . Buchanan . Kallee . Varley . Russell . 2024-01-10 . Controversial Queensland dam is suffering 'too many issues' and will have to be completely rebuilt, operator says . 2024-01-11 . ABC News . en-AU . 10 January 2024 . https://web.archive.org/web/20240110113848/https://www.abc.net.au/news/2024-01-10/queensland-paradise-dam-to-be-rebuilt/103306884 . live .
  5. Web site: Paradise Dam. Sunwater Current Water Storage Information. Sunwater. 16 November 2015. 15 February 2016. https://web.archive.org/web/20160215003857/http://www.sunwater.com.au/home/water-storage-levels/paradise-dam. live.
  6. Web site: Register of Large Dams in Australia. Excel (requires download). Australian National Committee on Large Dams. 2010. 15 November 2015. Dams information. 12 December 2013. https://web.archive.org/web/20131212120804/http://www.ancold.org.au/wp-content/uploads/2012/10/Dams-Australia-2010-v1-for-website.xls. dead.
  7. http://www.sunwater.com.au/__data/assets/pdf_file/0019/9226/Paradise_Dam_Upstream_Fishway_Monitoring_Program.pdf Paradise Dam Upstream Fishway Monitoring Program Final Report June 2011
  8. http://www.sunwater.com.au/__data/assets/pdf_file/0018/9225/Paradise_Dam_Downstream_Fishway_Monitoring_Program.pdf Paradise Dam Downstream Fishway Monitoring Program Final V1.1 Report February 2012
  9. http://www.envlaw.com.au/paradise.html Paradise Dam case
  10. News: Jodie . van de Wetering . The official history of Paradise . https://web.archive.org/web/20060112204000/http://www.abc.net.au/widebay/stories/s1456622.htm . 12 January 2006 . . Australian Broadcasting Corporation . 9 September 2005 . 13 July 2015 .