Equipment sharing plan could help utilities deliver clean water after bushfires

Following a bushfire, gaining access to effective treatment technology can make a huge difference for small townships mitigating blackwater events. One group of water professionals has designed an equipment pooling system to help relieve the burden.

Posed with the challenge of devising a way to help mitigate impacts on bushfire affected catchments related to water supplies during the AWA Victoria Bushfire Recovery Hackathon, the Ace team worked to devise a Blackwater Emergency Treatment Rapid Response (BETRR) solution using a proven technical solution: PR Power Siltbusters.

“Severe rainfall after bushfire washes debris from the burned area into the catchment, creating blackwater events in waterways,” Ace team member Tansy Huang said. 

“People typically observe turbidity, colour and metal spikes in stream flow for 72 hours or more during an event. It can become a really big burden to portable water supply. During these blackwater events, communities relying on stream flow are usually most exposed to the risk.”

Huang’s team consulted with experts from Victorian utilities that had extensive experience with responding to blackwater events in order to gain a foundational understanding of the pressures and problems associated with responding to post-bushfire heavy rain events.

“We had several sessions with our mentor, John Day, from North East Water (NEW), which was one of the water utilities severely impacted by the 2019-20 bushfire season,” she said.

“He shared NEW’s experience with bushfire recovery in terms of mitigating impacts on their water catchments, as well as maintaining portable water supply to bushfire affected communities.

“East Gippsland Water also provided us with background information relating to their experience with bushfire recovery.”

Huang said currently there are a few blackwater emergency response practices and, rather than attempted to create a new practice, her team focused on devising a system that would ensure the most effective and reliable practice could be implemented within a critical time frame.

“The current practices in maintaining water supply during these events include water carting, back-up water supply, including the use of groundwater,” she said.

“Another option that’s commonly used in the industry is to deploy ‘Siltbuster’ clarifiers. It’s a mobile unit, the size of a truck, and it provides a vital primary treatment to water sources with high levels of sediments, which is connected to the water treatment plant for secondary treatment.

“This machine is designed to remove sediment from water, assist operations in areas affected by blackwater events, thereby lifting the burden off the treatment plant.”

Rapid response

Huang said her team discovered that one of the primary challenges was how to engage in a blackwater event treatment response within a short amount of time.

“Blackwater events are a recurring issue in bushfire affected regions, which are often triggered by significant rainfall, typically greater than 20 mm. Communities in small townships, which have no raw water storage or alternative water supply and rely on stream flow, are often most vulnerable,” she said.

“One of the primary challenges water utilities face is how to get a response in place within that time frame to secure the potable drinking water supply and to maintain it.

“Furthermore, most of the options available are planned once the blackwater event starts to occur. Meeting the demands of a blackwater event often results in ad hoc planning.”

Following initial research, Huang said her team’s focus was to design a dynamic solution that would improve water utilities’ access to the "Siltbuster" — or similar technology — and support operators in using these systems. 

The aim is to reduce the lead time and improve the efficiency, cost-effectiveness and resilience of water supplies.

“Across Victoria there are 19 water service providers, but only some of these utilities have immediate access to the PR Siltbuster technology. Most of the time, when not in use, the technology sits in a storage facility,” she said.

“Our idea was to pool the equipment and organise for the technology to be freighted to the water authorities that need help during blackwater events. Our solution focused on designing a technology-share format.

“Just like Uber, where you share your ride, but instead it is a system that facilitates the sharing of water-treatment equipment and technical support across the industry. Furthermore, response support is built into the system as well.”

Deep knowledge

The solution required gaining an understanding of bushfire prone areas in Victoria, as well as areas that are prone to heavy rainfall events, Huang said.

“For the BETRR solution to be effective, we need to ensure the equipment is strategically located around the state based on needs,” she said.

“We wanted to ensure that a reasonable number of the units are located across Victoria so that when a blackwater event does occur, individual water authorities have much easier access to the technology when they need it.

“Further to strategically locating the units, standard operating procedures, user guide, instructional videos would also be made available through the platform component of the system.”

Huang said the solution also involves post-event learning capabilities, to ensure that the process is reviewed in order to strengthen the technology sharing platform moving forward.

“In Victoria, there are annual pre-bushfire season briefings and training. As part of our solution, we also propose an annual pre-bushfire season training, where operators can learn about Siltbuster (and other technology offered) with people from other water utilities, DELWP and CFA,” she said.

“Importantly, we wanted to ensure our solution had the capacity for continued improvement. We think it’s really important to include debriefing sessions following major events in order to carry forward lessons learned into the next season.

“These debriefing sessions would involve a review of the strategic locations of the units and, if needed, a relocation of the equipment as well.”