Paradise Dam (Queensland)

Paradise Dam
Paradise Dam is located in Queensland
Paradise Dam
Paradise Dam
Location of the dam wall in Queensland
CountryAustralia
Locationnear Biggenden, Wide Bay-Burnett, Queensland
Coordinates25°21′01″S 151°55′07″E / 25.350231°S 151.918602°E / -25.350231; 151.918602
PurposeIrrigation
StatusOperational
Construction began2003
Opening date2005
Construction costA$240 million
OwnerBurnett Water
OperatorSunWater
Dam and spillways
Type of damGravity dam
ImpoundsBurnett River
Height37 m (121 ft)
Length940 m (3,080 ft)
Dam volume400×10^3 m3 (14×10^6 cu ft)
Spillways1
Spillway typeStepped spillway chute with a smooth ogee
Spillway capacity33,000 m3/s (1,200,000 cu ft/s)
Reservoir
CreatesLake Paradise
Total capacity300,000 ML (240,000 acre⋅ft)
Surface area3,300 ha (8,200 acres)
Maximum water depth38.2 m (125 ft)
Normal elevation67.6 m (222 ft) AHD
Paradise Dam Mini Hydro
Coordinates25°21′04″S 151°55′10″E / 25.35111°S 151.91944°E / -25.35111; 151.91944
OperatorSunWater
Commission date2006
TypeConventional
Turbines1 X 2.7 MW (3,600 hp) Kaplan

The Paradise Dam, also known as the Burnett River Dam, is a gravity dam across the Burnett River, located between Coringa and Good Night northwest of Biggenden and 80 kilometres (50 mi) southwest of Bundaberg 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 37.1 metres (122 ft) high and spans approximately 600 metres (2,000 ft). The dam is named for the ghost town of Paradise, flooded following construction.[5][6]

Approval to build the dam was given in 2002.[7] 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 300,000-megalitre (240,000 acre⋅ft) capacity dam cost A$240 million to complete and was intended to assist the social and economic growth of the region.

The dam 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.[8][9]

When the Paradise Dam is full, water is released over a stepped spillway followed by a stilling basin. The spillway chute is 335 metres (1,099 ft) wide with a smooth ogee profile, ending a few small steps leading to 1V:0.64H–stepped chute with a step height of 0.62 metres (2 ft 0 in). 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.

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.[3] Construction to lower the dam wall height by 5.8 metres (19 ft) started in May 2020, under contract to CPB Contractors.[10] 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]

Fishways

An upstream fishway, known as the upstream fishlift, was installed on the dam for a cost of A$12 million. It consists of a 7,500-litre (1,600 imp gal; 2,000 US gal) 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 A$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.[11]

SunWater released final fishway monitoring reports in 2012 for the upstream fishway[11] and the downstream fishway.[12] 25 species different species have been recorded successfully using the upstream fishway.[11] No lungfish have been recorded using the downstream fishway and very few have been recorded using the upstream fishway.[8] 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.[7][13]

See also

References

  1. ^ "Lake Paradise (entry 44148)". Queensland Place Names. Queensland Government. Retrieved 18 November 2015.
  2. ^ "Paradise Dam Essential Works: Fact Sheet: Roller Compacted Concrete Sampling & Testing" (PDF). SunWater. September 2020. Archived (PDF) from the original on 9 July 2021. Retrieved 30 June 2021.
  3. ^ a b c Marie, Johanna (21 May 2020). "Concrete in Paradise Dam wall may have failed design standard, inquiry finds". ABC News. Archived from the original on 20 July 2020. Retrieved 24 August 2020.
  4. ^ a b Marie, Johanna; Buchanan, Kallee; Varley, Russell (10 January 2024). "Controversial Queensland dam is suffering 'too many issues' and will have to be completely rebuilt, operator says". ABC News. Archived from the original on 10 January 2024. Retrieved 11 January 2024.
  5. ^ "Paradise Dam". Current Water Storage Information. SunWater. Archived from the original on 15 February 2016. Retrieved 16 November 2015.
  6. ^ "Register of Large Dams Australia-2015" (Excel. Requires download. Row 396). ANCOLD. January 2022. Retrieved 5 March 2026.
  7. ^ a b "Paradise Dam case". Environmental Law Australia. Archived from the original on 9 April 2013. Retrieved 13 July 2015.
  8. ^ a b "After 400 million years, is time finally running out for this ancient fish?". ABC News. 30 June 2018. Retrieved 8 December 2024.
  9. ^ "Paradise Dam case". Environmental Law Australia. Retrieved 9 December 2024.
  10. ^ "Paradise Dam Essential Works | Fact sheet: 5.8 metre lowering" (PDF). SunWater. May 2020. Archived from the original (PDF) on 25 February 2024. Retrieved 9 December 2024.
  11. ^ a b c "Paradise Dam Upstream Fishway Monitoring Program Final Report" (PDF). SunWater. June 2011. Archived from the original (PDF) on 10 April 2013. Retrieved 13 July 2015.
  12. ^ "Paradise Dam Downstream Fishway Monitoring Program Final V1.1 Report" (PDF). SunWater. February 2012. Archived from the original (PDF) on 10 April 2013. Retrieved 13 July 2015.
  13. ^ van de Wetering, Jodie (9 September 2005). "The official history of Paradise". ABC Wide Bay. Australian Broadcasting Corporation. Archived from the original on 12 January 2006. Retrieved 13 July 2015.
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