Queensland flood information: Thomson River, Barcoo River and Cooper Creek

This document describes the flood risk and previous flooding in the Thomson River, Barcoo River and Cooper Creek catchments.
Last updated: July 2026.

Flood Risk

The Thomson-Barcoo-Cooper catchment drain an area of approximately 237,000 square kilometres and are part of the largest basin in Queensland, the Lake Eyre Basin. The Lake Eyre basin is the largest and only internal drainage system in Australia with no external outlet, and which covers over 1.2 million square kilometres of central Australia. Floodwaters reach Lake Eyre usually after major flood events in the Cooper Creek catchment.

The two main tributaries, the Thomson and Barcoo Rivers, merge into the Cooper Creek approximately 40 kilometres upstream of Windorah. The Thomson River and its tributaries flow in a general southwesterly direction and it has several of the larger towns of the region, including Longreach and Muttaburra, along its banks. The Barcoo River flows in a general westerly direction and has major centres such as Isisford, Blackall, Barcaldine, Jericho and Tambo in its catchment.

The Thomson-Barcoo-Cooper catchment can be divided into two distinct areas:

• Upstream of Windorah, numerous well-defined creeks and channels flow into the Thomson and Barcoo Rivers.
• Downstream of Windorah, the typical wide ranging channel country develops along the Cooper Creek.

In the dry season, the channels are restricted to numerous lagoons and claypans. During the wet season the actual main channel becomes hard to define, particularly when the river at Windorah could be up to 40 kilometres wide. Below this point, however, in a big flood, the area becomes a huge inland sea broken only by a few ridges and numerous stunted trees.

Major flooding requires a large-scale rainfall event over the Thomson and Barcoo Rivers and Cooper Creek catchment. This most typically occurs over Summer and early Autumn following an intrusion of tropical moisture into the region, often associated with the passage of a tropical low or ex-tropical cyclone. Flooding has been recorded over the typical dry season – April to November – associated with northwest cloudbands, but is far less common. The following can be used as a rough guide to the likelihood of flooding in the catchment:

75 mm in 24 hours over isolated areas, with lesser rainfall of 50mm over more extensive areas will cause stream rises and the possibility of minor flooding. If lesser rainfalls have been recorded in the previous 24 to 72 hours, then moderate to major flooding may develop.

100 mm in 24 hours will cause isolated flooding in the immediate area of the heavy rain.

100 mm or heavier falls in 24 hours over a wide area will most likely cause major flooding particularly in the middle to lower reaches of the Thomson and Barcoo Rivers extending downstream to Windorah on Cooper Creek.

Previous Flooding

Records of large floods in the area extend back as far as the late 19th century, with the most significant episodes of flooding occurring in 1893, 1906, 1949, 1955, 1963, 1974, 1990, 2000, 2025, and 2026. Some of the more recent floods are summarised in table form below, where the Longreach peak heights are from the automatic gauge. At Longreach, a record peak height of 7.11 m was recorded in May 1955 at an older manual site (no longer used) but may not be representative of the current automatic site.

Significant but separate floods occurred across the catchment in 2025 and 2026. The March to April 2025 flooding resulted from inland trough interacting with deep tropical moisture, producing prolonged heavy rainfall across western Queensland. Large parts of western Queensland received up to 4 times their March average rainfall, while in four days from 23 to 26 March, parts of southern and south-western Queensland had more than their annual average rainfall. Sunbury recorded a record daily rainfall total of 347 in the 24 hours to 9am on 24th of March and a 7-day accumulative total of 602 mm to the 31st of March, well in excess of the region's average annual rainfall. Dozens of residents were evacuated by helicopter, as 25 homes in Jundah were inundated. Critical infrastructure such as roads were significantly damaged and more than 100,000 livestock confirmed missing or deceased in floodwaters.

Flooding occurred in March to April 2026 following repeated rainfall, including rainfall associated with tropical low 29U as it moved westwards and weakened over central Queensland by 8 March. Widespread major flooding developed as floodwaters moved downstream through the catchment. Floodwaters caused widespread road closures and protracted isolation of rural properties and low-lying areas.

Previous flooding events on the Barcoo River

Flood Event	Jericho	Barcaldine	Blackall	Isisford
January 1974	-	-	-	6.83
April 1990	3.80	8.96	7.30	9.20
January 2004	-	-	4.25	7.39
January 2008	3.08	-	5.15	8.68
December 2010 / January 2011	3.80	-	5.51	6.97
February 2012	3.39	-	7.02	7.39
March/April 2019	2.5	-	-	7.56
March/April 2025	-	-	-	6.13
March/April 2026	-	6.75	-	5.69

 

All heights are in metres on flood gauges.

 

Previous flooding events on the Thomson River and Cooper Creek

Flood Event	Camoola Park	Longreach	Stonehenge	Jundah	Windorah
March 1971	2.84	3.30	5.94	7.54	7.65
January 1974	7.16	6.82	6.88	8.38	8.48
April 1990	6.80	6.39	5.86	7.55	7.95
February 1991	5.52	5.71	4.70	6.45	6.70
February/March 2000	7.42	6.95	6.42	7.85	7.45
January 2004	4.60	5.05	5.16	6.68	7.08
January 2008	4.65	5.28	3.80	5.20	5.95
December 2010 / January 2011	-	4.62	-	4.05	5.22
February 2012	4.30	4.76	3.00	4.32	5.37
March/April 2019	3.10	3.16	4.10	5.75	6.16
March/April 2025	5.10	5.37	7.40	8.70	8.50
March/April 2026	6.60	6.16	4.65	6.35	6.45

 

All heights are in metres on flood gauges.

 

This chart shows flood level classifications of recorded flood gauge height observations of the Thomson River at Longreach.

This chart shows flood level classifications of recorded flood gauge height observations of Cooper Creek at Windorah.

The totem pole shows flood level classification and associated impacts related to local reference sites, along with recorded flood gauge height observations of notable flood events that have occurred on the Thomson River at Longreach.

The totem pole shows flood level classification and associated impacts related to local reference sites, along with recorded flood gauge height observations of notable flood events that have occurred on the Cooper Creek at Windorah.