Nyngan and Charleville, April 1990

The previous weeks had been wet over central Queensland, with some flooding, when on 18 April 1990 a strong upper level low moved towards South Australia and became stationary. Over the next three days, this system dumped upwards of 150 mm of rain - with isolated totals to 350mm - across large areas of central Queensland. Falling on saturated catchments, major flooding quickly developed on the Warrego and Maranoa Rivers, and many other inland systems. The towns of Jericho and Augathella were flooded, and on the 20th two-metre deep floodwaters bisected the town of Alpha as the Alpha Creek rose a metre above its previous record. A section of the Longreach railway was washed away.

Early on 21 April, Charleville residents were rudely awoken by the rapidly rising Warrego River. Many were forced to retreat to their rooftops and had to be rescued by helicopter. Late that day the river peaked at over 8.5 metres, 1.5 metres above the previous record. Levee banks were overwhelmed, and as floodwaters spread through the town, the entire population of 3500 was evacuated to the airport. Following an uncomfortable couple of days, residents returned to confront the damage: houses torn from stumps, gaping holes in roads, stinking mud over everything. Downstream, Cunnamulla residents fared better as the river stopped rising when it was 85cm below the top of the levee banks.

“The town of Charleville inundated by the April 1990 floods. A vast area of normally semiarid country in central Queensland and northern NSW was under water.” (Photo courtesy of Emergency Management Australia )

A developing surface low then moved southeast, taking the torrential rains across large areas of New South Wales west of the Divide. There was major flooding on the Lachlan, Macquarie and Castlereagh Rivers, among others. As the Bogan river rose, residents in Nyngan desperately attempted to raise levee banks. Over 200,000 sandbags were laid in four days, but to no avail. The levees were breached on the 23rd, as the river surged to 5.2 metres, nearly a metre higher than the previous record. Most of the town was inundated, and the population of 2500 was evacuated by helicopter to Dubbo, 160km away.

Continuing southeast , the low moved off the Victorian east coast, generating torrential rains over Gippsland on 20 and 21 April - up to 350mm within 48 hours on the mountains. Major flooding occurred on the Thomson and Avon Rivers, and the Mitchell River flooded many hectares of vegetable crops on the river flats and cut the highway. People were evacuated from caravan parks and low-lying areas, and 150 homes were flooded. Though the damage bill ran to many millions of dollars, commercial centres, built on high ground in this flood-prone region, largely escaped.

All told, property losses from the three-state deluge were enormous, not only from flooded towns and damaged roads and bridges, but in the thousands of drowned sheep and cattle, and in the thousands of hectares of ruined crops. The floods also claimed six lives.