Lake Rowlands plan is to raise wall by 2.2 metres

STILL FLOWING: Lake Rowlands is still overflowing.
STILL FLOWING: Lake Rowlands is still overflowing.

Ever since the sky has opened up and the rain has been bucketing down, interest in water security hasn't been front and centre in many people's thinking.

In December of 2019, when Lake Rowlands was at around 30 per cent capacity, the NSW Government committed $1 million of funding for the completion of a feasibility study for the dam's augmentation as part of its emergency response to the drought in regional NSW.

The first stage involved developing business cases to decide which of the options, raising the wall by up to five metres or building a new dam further downstream, would go onto stage two of the process.

That stage includes a detailed concept design of the preferred option, a Review of Environmental Factors (REF), and the completion of a final business case.

The dam is continuing to spill even now, and for the general manager of CTW Gavin Rhodes an announcement by the NSW Department of Planning, Industry and Environment for CTW to proceed with the second stage of the feasibility study of raising the wall at Lake Rowlands by 2.2 metres is welcome news.

"Approval to proceed with this vital urban water security project is fantastic news," he said.

"Although the study had been delayed significantly due to additional water modelling work by DPIE Water for the Lake Rowlands Augmentation and Lake Rowlands to Carcoar Pipeline projects, it is very pleasing that we can now continue and finalise our study."

Canowindra's water supply comes from Lake Rowlands and Central Tablelands Water has estimated that 16 gigalitres of water has spilled over the dam wall since July 2020, well in excess of three times the existing capacity of the lake.

"Raising the height of the existing dam wall by 2.2 metres will increase the capacity of Lake Rowlands from 4.5 gigalitres to 8 gigalitres," Mr Rhodes said.

"This will help shore up the water security needs of our existing consumers now and well into the future."

Mr Rhodes acknowledged that the spills have environmental and downstream user benefits, and those impacts will be a part of the REF report.

"In 2016 approximately 53 gigalitres flowed over the dam wall and following the drought breaking rains in 2020, 16 gigalitres has spilt since July," he said.

"Although 3.5 gigalitres will be held back with the raising of the wall, the REF will consider potential environmental impacts of this proposed augmentation."

The Lake Rowlands Augmentation project aligns with the final business case of the Lake Rowlands to Carcoar Dam Pipeline project currently being undertaken by WaterNSW.

Both projects are expected to be completed by the end of 2021.