Queensland

No plans to release water from "full" south-east Queensland dams

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Queensland has no plans to release water from  the south-east's biggest dams ahead of the January to March storm and cyclone season early in 2017 despite many of its major dams being full.

This comes as south-east Queensland's three biggest dams – Wivenhoe, Somerset and North Pine – are also "temporarily" operating with lower water storage levels while Somerset is being revamped.

Somerset Dam now has lower flood storage.

"The upgrade involves filling in the breezeway bays along the (Somerset) dam wall with concrete to increase the dam's flood capacity, while investigations continue into further improvement works," SEQ Water's website shows.

"Water stored in Somerset is released into Wivenhoe, which in turn supplements the natural flow of the Brisbane River," the website says.

"Lowering both dams has allowed us to increase the temporary flood storage space in Wivenhoe Dam to compensate for the reduced maximum allowable flood level in Somerset Dam."

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This "lower storage levels" situation could continue until 2018, the SEQ Water website makes clear.

Additionally Somerset, Wivenhoe and North Pine are temporarily classed as "full".

However the Queensland Government has no plans to release water from dams in case storms hit during January and February.

"There are no plans to release water from these dams prior to the storm season," a spokeswoman for Water Supply minister Mark Bailey said.

"All three gated dams are currently operating with temporary full supply levels below their drinking water supply level capacity," she said.

"Seqwater will commence releases from gated dams if storage levels exceed the enacted temporary full supply levels as a result of rainfall in the dam catchments and inflows into the dams."

The Queensland Government and SEQ Water, the organisation that manages most South East Queensland dams, rely on forecasts from the Bureau of Meteorology.

"Based on the forecasts available from the Bureau of Meteorology and Seqwater information, there are no plans to temporarily lower these gated dams further," the spokeswoman said.

Dam levels – as of 28 December 2016.

Bigger dams with 'gates'

  • Wivenhoe – 72.9 per cent. "Operating with "temporary lower storage."
  • Somerset – 76.8 per cent. "Operating with temporary lower storage."
  • North Pine: 57 per cent "Operating with temporary lower storage."

'Ungated' dams ie where water flows over the spillway when it reaches 100 per cent full.

  • Enoggera Dam - 97.6 per cent
  • Ewen Maddock Dam – 91.5 per cent
  • Hinze Dam – 94.8 per cent
  • Lake Manchester – 94.8 per cent
  • Maroon Dam – 98.2 per cent
  • Moogerah Dam - 89.7 per cent
  • Wyralong Dam – 98.4 per cent.

The Queensland Government has introduced "temporary full supply" levels at Somerset and Wivenhoe dams.

"These temporary full supply levels will remain in place until dam improvement work at Somerset Dam is completed," the spokeswoman said.

North Pine Dam has been operating with lower water storage since 2015.

Water Supply Minister Mark Bailey has been kept informed by SEQ Water of the most recent water supply issues, his spokeswoman said.

"Seqwater's most recent advice to the Government on 26th December is that for its three gated dams – Wivenhoe, Somerset and North Pine – is that it would take substantial rainfall in the catchments before the dams require to be operated in accordance with their current dam operations rules," she said.

 South-east Queensland's 12 major dams are now sitting at an average of 75 per cent capacity.

"To compare, this time last year, the combined storage level of South East Queensland's 12 key drinking water storage dams was sitting at about 91%," the spokeswoman said.

However it is unclear the exact significance of the reduction at Wivenhoe, Somerset and North Pine dams – has on this situation.

Water Supply Mark Bailey has the legislative authority to reduce SEQ's dam levels.

 "Assessments for the current wet season concluded that current dam operating levels should be maintained," the spokeswoman said.

Elders long range weather forecasting predicts higher than average rain for South East Queensland in "late summer to autumn" from March to May/June.

"The seasonal warming of the seas surrounding Australia towards the end of summer could bring increased chances of wetter conditions to the eastern coastal fringe towards the end of summer/early autumn. "