How Kangaroo Island's water infrastructure came back from catastrophic fires
The summer of 2019/20 was extreme. Here, Michael Webber looks back on the fires that raged across South Australia's Kangaroo Island, and the work that went into the recovery.
It seems we’ve always had catastrophic bushfires, but never before have we had so many, for so long and so severe across so much of the country. I have always lived in the Adelaide Hills and my parents’ fear of and vigilance against fire has rubbed off on me.
This summer’s first fire exposure was during the Cudlee Creek fire. Fortunately, my home never came under threat but that night my partner and I drove into Harrogate, past burnt out cars, and burning trees and through showers of embers to collect and relocate four horses who were unharmed but had their fences destroyed – in fact they were still burning while we were there. We certainly considered whether we should drive in, but it was an easy decision really; our friends were asking for help and they’d driven the road reporting it was clear and safe.
By the following day, the Cudlee Creek fire had calmed down but thunderstorms over the west end of Kangaroo Island started fires, which would burn out of control for over a month. Over Christmas and New Year, it looked like the bushfire situation on Kangaroo Island was calming down, but hot and windy weather returned on 3 January and the situation escalated.
On catastrophic fire danger days I’m required to work from home unless there is essential work, so on this day I periodically checked on the animals and looked out for smoke on the horizon (that being the influence from my parents' concern of fires), and I swear I could feel the moisture seep out of my eyes – it was that hot and windy. On 3 January the fires still burning on Kangaroo Island raged south before a wind change pushed them east with the entire island coming under emergency or watch and act warnings. There are some videos online showing the ferocity of the fires from the CFS volunteers which are truly shocking.
The fire this day was devastating, claiming two lives as well as many homes, tourist attractions, the luxury resort, upwards of 100,000 livestock and countless numbers of wildlife. The Middle River WTP also burnt, destroying the office and communications buildings, and embers had fallen into open conduit ends through the plant destroying parts of the power, communications and chemical systems. This left the bulk of the plant intact, but it was crippled without the power and control systems.
On 5 January, I travelled to Middle River, finding myself again driving past destroyed buildings, burnt out cars and still burning trees. Mobile chlorine dosing stations and generators had arrived at site to restore water flow from the reservoir and provide disinfection. The WTP raw water bypass was opened and chlorine dosing started. My task onsite initially was to set chlorine dose rates and water flow rates. Without any telemetry I gauged water demands by change in tank level over time measured with rope and weight, and I monitored chlorine with my field equipment. The flow restoration began just as the tank volume fell to less than 1%. When we drove along the water main only small pockets of air were discharged indicating we never fully lost supply but couldn’t have gotten any closer to doing so. Interestingly, we discharged this air from fireplugs, the lids of which were still too hot to touch from the fire two days before without gloves. At times we had to dose 40 mg/L chlorine to maintain required disinfection, which was up from the usual 4-6 mg/L, and this was at 4 kg/h gas flow, the maximum reliable flow from a chlorine drum without it freezing.
Many other tasks in the first week revolved around maintaining water flow for the community and fire fighting as well as ensuring and validating the safety of our raw but disinfected water. Middle River WTP backs onto the airstrip used by the CFS for firefighting – they lost equipment but were also back operational when we were there. Each time a plane would take off (as frequently as every 5 minutes) a blast of ash and dust blew into the treatment plant site getting everywhere into our eyes, ears, nose, mouth and everywhere else despite our safety gear. Sweat and sunscreen certainly didn’t help the situation.
After a long, hot, dirty day's work there is nothing better than a long shower, but knowing the water supply situation was dire and the community had been asked to limit water for only essential use, I developed a method to have an effective shower in around 20 seconds of water use, which involved first applying shampoo and soap liberally before running, not quite making a lather but then with water at low flow 20 seconds allowed a decent lather and rinse.
Working here at this time was difficult as the air was thick with smoke, but also thick with the ant smell of formic acid from termite mounds that burnt and boiled from the inside out for days after the fire went through. The air also smelled of resin, the result of the yuccas on the island being burnt. The worst sight over there was being unable to avoid seeing injured livestock being destroyed and buried.
On 9 January the fire again raced out of control, stretching from the north coast to the south coast before the wind changed and it again raced east towards more major Island infrastructure. This isolated us from the WTP for about 48 hours and for the first time I felt apprehension about being there with the bushfire. Kingscote was isolated with all roads out of the town closed. By now the army had been deployed to the island. At first it was surreal seeing army vehicles and soldiers all over the island, but it soon became normality. I remember thinking on this day that it was scary that despite the resources being thrown at the fire (aircraft, fire trucks, the army and heavy earthmoving equipment) it still burnt out of control. Nothing could stop it except a cool, rainy change in the weather.
We worked long days onsite and I backed that up with hours in our accommodation tidying up information to be sent back to Adelaide. I spent about 30 days on the island from 5 January to 20 February swapping over with colleagues for rests in between stints of up to 8 days.
DSM Construction handled the civil work, leaving the areas of the site they worked on in a better state than before the fire. Sage Automation assisted with rewiring the site, the army had flown a modular water treatment plant from Queensland and also provided security assistance manning sites that had lost the fencing. Osmoflo mobilised treatment plants as a contingency if the WTP proper was unable to operate for an extended time and we watched for days as SAPN worked tirelessly on every stobie pole in the fire scorched ground to restore power. Along with our skilled SA Water personnel from all over the state, the team got the Middle River WTP back up and running within 10 days of being burnt, that included three days of being unable to access the site- an amazing effort from all involved.
Two key activities helped us, well me at least, keep a level head among the long days, short sleeps and some awful sights. One was regrouping and debriefing over dinner at night, and the other was being greeted onsite by Maggie the border collie. She accompanied one of the DSM Construction crew but of course stayed outside the site as per corporate policies.
The fires that had merged to become what was named the Ravine Fire was declared controlled on 20 January, 2020. On 30 January I visited the island for a one-night stay to finalise some issues when Kangaroo Island received some badly needed rain. Instead of gentle intermittent rain, it was a short deluge of around 30 millimetres in 20 minutes and 63 millimetres in just over 24 hours. This turned the landscape around the plant into an inland lake, and washed ash and other debris into the reservoir. It also meant my one-night visit turned into an eight-night visit while we tried to adjust the treatment plant to remove manganese. Sediment control barriers in the catchment filled with around 200 tonnes of material but the reservoir and water quality was still impacted enormously.
The dissolved organic carbon composition quickly became difficult to remove through the WTP’s magnetic ion exchange (MIEX) process and coagulation, and the loss of all dissolved oxygen caused soluble manganese to rise to 0.9 mg/L at the inlet, as well as taste and odour issues. To oxidise manganese, we installed blowers into the settled water prior to filtration and dosed sodium hypochlorite and sodium hydroxide in the same location. Doing so was successful at removing manganese to a suitable level. The reservoir water quality would continue to change causing more challenges and we’re waiting to see what winter will bring.
Connection with Kangaroo Island
Growing up, my family was fortunate to have a house on Kangaroo Island and while I lived in the Adelaide Hills a lot of my childhood was spent on the island, where I learnt how to swim in the ocean, ride a bike and fish. I became fascinated with nature exploring the scrub and life in the water. As a result, the island feels like my home. I’m lucky to work on Kangaroo Island and I’m proud of being able to work for the community. It was heartbreaking seeing the devastation from the fires but I’m glad to have been able to help.