On 20 January, the Bureau of Meteorology issued a severe weather warning for heavy rainfall and potential flash flooding across central and northern parts of the South Australia. Early on 21 January heavy rainfall began to fall on the western Eyre Peninsula with flooding and widespread damage reported.
Isolated thunderstorms continued for the next few days. Early the following week an upper low-pressure system and associated surface trough developed. There was an intensification of rainfall across the northwest of the state which moved slowly southwards to the northern parts of the Eyre Peninsula (including Kimba and Tarcoola) and eastwards to western Northeast Pastoral and Flinders. Much of the Eyre Peninsula, Yorke Peninsula and southern parts of the Pastoral districts recorded more than five times their January average rainfall.
As the control agency for flooding and severe weather, the South Australia State Emergency Service (SASES) was responsible for the control of the response to the emergency. The SASES State Control Centre (SCC) was activated on 21 January and on 28 January, supported by liaison officers from several agencies and functional support groups. The SCC remained activated for 17 days and a Major Emergency Declaration was signed by the State Coordinator, lasting for 14 days. Two SASES regional coordination centres were also activated.
Major damage was caused in 45 municipalities, the most extensive on the Eyre Peninsula and in the Northwest Pastoral area, including major disruptions to road and rail networks connecting the state to Western Australia and the Northern Territory.
The area of impact is comprised of vast empty space and farming land, low population including some isolated and vulnerable populations, mining and pastoral communities. The response was very complex due to the distances involved, lack of government resources in remote areas, reliance on private operators, access and remoteness making assessment of damage very difficult, large areas remaining under water for a protracted period and the overlay of the COVID-19 pandemic.
Damage, particularly to road and rail infrastructure, was arguably the most significant impact of the event, leading to critical consequences. Numerous highways, outback roads and tracks were closed due to flooding. The closure on 25 January of the Stuart Highway north of Glendambo, with large sections under water, had the most significant impact. The highway remained closed until 6 February, with a restricted reopening starting with essential heavy freight vehicles and emergency services. The highway was covered by approximately half a metre of water in some areas. The flood water at Glendambo was contained by high terrain, a ‘natural bowl’, and water levels were only dropping 40 mm per day. It was estimated that it would be 12 days minimum for restoration due to the time needed for water levels to subside, without human intervention such as high-volume pumping.
The feasibility of escorted heavy fleet along the closed Stuart Highway was assessed, however there were concerns about further damage to the road surface, which was already weakened and soft in places from inundation. An alternative Type II Network Route (for B Triples) was assessed for road transport to Darwin by the National Heavy Vehicle Regulator (NHVR). This route extended from Burra to Broken Hill, Bourke, Mount Isa and Darwin. The NHVR sought urgent approvals from South Australia and New South Wales to gazette the route, which was approved for a 28-day period for transporting essential foods and designated transport providers.
The route largely consisted of Type II approved roads and allowed road freight into Darwin and south to Alice Springs/ Coober Pedy, but the trip added two days of driving each way. By 30 January the new heavy vehicle route had been compromised with floodwaters near Camooweal on the Queensland-Northern Territory border. Trucks continued to travel through shallow floodwaters over the road, whilst the NHVR investigated alternative options.
The east-west and north-south rail from Adelaide was closed for 24 days due to damage east of Tarcoola (18 washaway sites over 300 km) interrupting supply to both the Northern Territory and Western Australia. In excess of 50 return freight train trips (1.5 km long of rolling stock) normally move each week to Perth for one operator alone. The Australian Rail Track Corporation (ARTC) restored the rail line by 15 February.
Rail operators, One Rail Australia and Pacific Nation, collaborated to establish a land bridge from Port Adelaide and Alice Springs to Whyalla and Whyalla to Kalgoorlie, to manage a small proportion (5%) of the freight that would otherwise have been shipped via rail.
Consequences of the road and rail impacts were far-reaching. Supply chain disruption had significant flow-on effects to communities and to the economy. Food security was significantly impacted in the north of South Australia and in the Northern Territory, and to a lesser extent in Western Australia.
Water security was also impacted as the majority of Australia’s Alum (used in potable water and wastewater treatment) and other water treatment coagulants are sourced from Western Australia and supplied via rail. Disruption to the east-west supply route had significant implications for the eastern seaboard states and South Australia. South Australia Water reported that it generally utilises approximately 160 tonnes of coagulant per week and needed resupply within seven days before contingencies needed to be implemented. Options for contingencies included the use of the desalination plant at Port Stanvac, use of the reserve supply in South Australia, potential procurement of supply from New Zealand or India and alternative treatment options and reduction in water and wastewater treatment.
Potential and realised health consequences included sickness associated with mosquitoes from standing water, delays to medical supply deliveries and flood damaged airstrips compromising Royal Flying Doctor Service flights in and out of remote sites for emergencies and scheduled clinics.
Several tourists were stranded at Coober Pedy as well as Indigenous people seeking to return to Country (APY
Lands). Of the stranded travellers, some had urgent medical appointments in Adelaide and were evacuated from Coober Pedy by the Royal Australian Air Force to the Edinburgh air base on a return food resupply flight.
Concerns for agriculture and animal welfare included the ability for pastoralists to provide access to shearers to enable them to shear sheep. February and March is shearing season and with so much water in the landscape the potential for large numbers of flies was high. The Department of Primary Industries and Regions (PIRSA) received requests for assistance from veterinarians and livestock owners to access properties in order to prevent and control blowfly strike in sheep.
PIRSA also reported the Dog Fence (built to keep dingoes out and runs 5,614 km from Darling Downs in Queensland to just above the Great Australian Bight on the Nullarbor Plain in South Australia) sustained considerable damage with 20 km of damage identified. Dogs had been confirmed as trespassing and baiting options were considered and implemented. PIRSA also had concerns regarding topsoil movement and loss on Eyre Peninsula with potential impacts on future grain yields.
The Department of Energy and Mines reported delays in mineral exports including iron ore, meaning deferred royalties into Treasury, and subsequent budget impacts. On 29 January it was reported that alternate transport routes were being explored. Simec Mining (Middleback Ranges) looked to truck approximately 2,000 tonnes of iron ore daily, with approximately 11 trucks operating seven days per week on a 12-hour basisfrom 7am to 7pm, for two weeks to Whyalla whilst rail infrastructure repairs occurred.
At the strategic level, the emergency response was supported by the South Australia State Emergency Centre (SEC) and working groups including the Water Security Working Group, the SEC Supply Chain Consequence Management Group, and the SEC Remote Communities Food and Supply Group. The State Recovery Coordination and Planning Group was established and developed a recovery plan and funding submission to the Australian Government for funding under Disaster Recovery Funding Arrangements.
At the federal level, support was provided through the National Coordination Mechanism (NCM) which involved representatives of the transport sector and retail food suppliers. The NCM met with Trusted Information Sharing Network industry representatives seeking information on any industry specific supply chain issues.
Through the NCM there was a coordinated industry approach to support supply chain challenges across Australia. The NCM engaged directly with industry, rail owners and operators, Australian Government departments, state and territory governments, and other related peak bodies to keep essential supplies moving and repair infrastructure as soon as possible.
Just-in-time regulations were facilitated to limit the application of anti-competition laws allowing collaboration/cooperation between industry competitors. The benefits of this forum were substantial and there is merit in South Australia considering the options for a domestic coordination capability for large scale events in the state.
The Australian Government National Situation Room monitored the situation across central and eastern Australia and coordinated imagery, forecasting and other support to the NCM. The Australian Defence Force also provided significant support under Defence Assistance to the Civil Community arrangements for resupplying food to Coober Pedy which had been cut off from usual supply routes and other taskings. Response to the severe weather and flooding event in South Australia and its impacts and consequences was wide-ranging. It involved the SASES, many South Australian government departments and NGOs, the Australian Government, commercial entities and infrastructure agencies. Given the unprecedented extent and scale of the impacts, there was a need for agencies to collaborate and innovate to support the community and minimise impacts.