Despite being part of Japanese culture for centuries, the practice of hot spring bathing has only just begun to heat up in Australia. Bore rehabilitation efforts across Queensland over the last few years have seen the re-emergence of natural springs and with that, an opportunity has also arisen.
The Great Artesian Basin is one of the largest underground freshwater resources in the world and is located beneath parts of Queensland, the Northern Territory, South Australia and New South Wales. It’s also a vital water source for more than 80 Queensland communities, with the water used for livestock and other domestic applications.
However, in recent years, uncapped bores and uncontrolled water flows have resulted in significant water loss, prompting the Queensland Government, in conjunction with the Federal Government, landholders and other stakeholders, to launch a rehabilitation program in the hopes of making the Basin watertight by 2032. The program involves rehabilitating or replacing bores, as well as substituting open bore drains with tanks, troughs and pipes.
So far, these efforts have seen almost 770 bores rehabilitated and 450 bores piped.
This has led to an increase in groundwater pressure, resulting in the re-emergence of Great Artesian Basin water and natural springs across outback Queensland. When this occurred in Cunnamulla, Paroo Shire Council saw an opportunity and seized it.
“The Paroo Shire Council team, mayor and councillors had a vision some years back to create a hot springs pool to take advantage of the wellness properties of the geothermically- heated water from Great Artesian Basin,” a spokesperson for Paroo Shire Council said.
“With funding from the State and Federal Government, this single pool developed, expanded and came to life as the seven-pool complex we have today.”
An outback hot springs experience
Although initially announced in 2023, Cunnamulla Hot Springs officially opened on 1 February 2024. Situated near the Warrego River, the Cunnamulla Hot Springs facility offers multiple mineral-rich geothermal pools and a cold plunge pool, as well as a sauna and steam room, all nestled under eucalyptus trees.
Owned by Paroo Shire Council and managed by Peninsula Hot Springs Group, the wellness facility provides guests with an opportunity to immerse themselves in the famous Australian bush, all while enjoying the geothermal water that comes from below.
It is hoped that the new wellness facility, which cost $11.7 million to establish, will provide a welcome boost to the tourism industry as hot springs enthusiasts leap at the opportunity to experience one of Australia’s most rural hot springs facilities.
Bringing the heat
Building a hot springs facility in rural Queensland is an enormous undertaking and involved the cooperation
and coordination of several teams. Aquatic Projects were responsible for the plant room and reticulation construction and installment.
With several pools boasting varying temperatures, the behind-the-scenes operation of the facility is complex and involves an intricate system of pumps and equipment.
A spokesperson for Aquatic Projects shared some insight into the different pools at the facility and their bespoke filtering, heating and operation requirements.
“Pools A and F work under the same body of water and have two modes of operation. The pool system may utilise ultra fine filtration with chlorine and acid, or have direct bore water supply at 25 per cent of the filtration flow. When filtration mode is used, bore water supply is only used to heat the pools at a desired temperature. Direct bore water mode will have pools at bore water temperature supplied and available at that time. Excess water by use of bore water into the pools is diverted to the lagoon.”
Pools B and C work under the same body of water and operate as per pools A and F. Pool D is a chilled water plunge pool utilising sand filtration with salt chlorination and acid for chemical control. Chilling is achieved via an electric chiller. Pool E has a constant bore water supply.
“Pool G is a spa-type pool utilising sand filtration with salt chlorination and acid for chemical control. This process includes a UV system to assist in keeping the reacted chlorine (combined chlorine) at an acceptable level, and heating of pool G is facilitated via an electric heat pump.”
Across such a large-scale operation, and with pools providing an assortment of different temperatures and experiences, it can be difficult to oversee and regulate the differing temperatures.
“Pools D and G are mechanically controlled via a chiller and heat pump. Pool E is straight bore water and cannot be controlled. Under filtration mode, pools A and F, as well as pools B and C utilise bore water via a temperature sensor that regulates bore water with a low voltage solenoid valve from the bore water supply.”
The Aquatic Projects spokesperson said that across the wellness facility, the biggest challenge in operations is presented by the combined pools.
“Any changes to flow need to be such that they are not excessive, as this will create an imbalance between the common line to the floor drains. The drainage system via the skimmer box arrangement also limits heating capacity as excess water created when heating is required is gravity fed into the lagoon at only 0.5 per cent fall.”
In addition to this, the spokesperson said that future projects at the facility would benefit from, and thus should investigate, maintaining dedicated systems for each pool, or using a common balancing tank.
“This would allow the supplementary heating via the bore system to be more aggressive in reaching the temperature set point, as you can discharge the excess water to the lagoon via the balance tank using a pump without impacting the pool operating level.”
Construction and installation challenges
The Aquatic Projects spokesperson said that construction of the wellness facility was complex as there was a need for an effective reticulation layout to all five of the pool systems.
“Plant room space was limited and connection points within the plant room required detailed coordination to also allow the equipment to be accessible for operation and maintenance.”
According to the spokesperson, the pumps that were used in the Cunnamulla Hot Springs facility were sourced from Australian distributors Waterco and Pentair. The pumps involved are mainly constructed from ABS/polyethylene and underwent stringent checks to ensure they were suitable for site conditions.
Between construction of the site and it being open to the public, rigorous testing of the facility overall was conducted.
“The pools have been tested for water flows, backwashing and chemical control. The main complications have been with the combined pools (A-F and B-C) in trying to maintain heating and water levels with skimmer box design.”
The spokesperson said that the constant pressure changes in bore water supply require the operators to make adjustments. As well as this, a photometer kit was supplied to the Cunnamulla Hot Springs team to enable them to monitor and maintain water quality.
Keeping things running
At Cunnamulla Hot Springs, preventative maintenance is a crucial method to avoid sudden breakdowns or equipment fault or failure.
Preventative maintenance measures undertaken by the facility’s team include:
- Cleaning dust filters to the pool switchboard
- Cleaning chemical injectors
- Removing any spilt acid to avoid corrosion of equipment
- Backwashing of filters as required
- Calibration of chemical controller
- Servicing of chiller and heat pump
- Desludging of back wash tank
Due to limitations relating to the inability to install balance tanks, as well as the new reticulation pipework, the Aquatic Projects spokesperson recommended that some additional work in the future would be able to mitigate the issues:
- Connecting a dedicated water level control pump to floor drain/skimmer box reticulation that can operate via the existing level sensor to the pools
- Adding a pressure regulating valve to the bore water supply for each pool, so any deviation in bore water supply does not alter the flow to the pools
- Installing a pressure regulating valve can also ensure bore water supply does not exceed pump capacity, as this allowing the pump to cycle and mitigating the risk of pool flood
With the bore rehabilitation ongoing, it’s not unlikely that more natural springs will re-emerge across Queensland, allowing more rural communities to capitalise on the environmental phenomenon and putting more towns on the map.
Featured image: Paroo Shire Council had a vision to harness the wellness properties of the geothermically-heated water from Great Artesian Basin. Image: Noelle/stock.adobe.com
