FLOOD WARNING SYSTEM
for the
THOMSON, BARCOO RIVERS AND COOPER CREEK

Cooper Creek at Nappa Merrie

Contained in this document is information about: (Last updated September 2009) Flood Risk Previous Flooding Flood Forecasting Local Information Flood Warnings and Bulletins Interpreting Flood Warnings and River Height Bulletins Flood Classifications Catchment Map

Flood Risk

The Thomson-Barcoo-Cooper catchment drains an area of approximately 237,000 square kilometres and is the largest river basin in Queensland. The catchment falls within the Lake Eyre basin, the largest and only co-ordinated internal drainage system in Australia with no external outlet, and which covers over 1.1 million square kilometres of central Australia. Floodwaters reach Lake Eyre after major flood events in the Cooper.

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 southerly direction and 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 and Tambo in its catchment.

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

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.

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 and 2000. Some of the more recent floods are summarised in table form later in this document.

Flood Forecasting

The Bureau of Meteorology operates a flood warning system for the Thomson, Barcoo Rivers and Cooper Creek basin based on a rainfall and river height observations network shown on the map. The network consists of a number of volunteer rainfall and river height observers who forward observations by telephone when the initial flood height has been exceeded at their station, as well as automatic telephone telemetry stations at Longreach, Barcaldine and Blackall, which are operated by the Department of Environment and Resource Management.

The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins for the Thomson, Barcoo Rivers and Cooper Creek during flood events. Quantitative flood forecasts are issued for locations at Longreach, Jundah, Blackall and Windorah when moderate flood levels are likely to be exceeded. 

Local Information

Local Council's throughout the Thomson, Barcoo Rivers and Cooper Creek catchment may be able to provide further details of flooding in your area.  

Flood Warnings and Bulletins

The Bureau of Meteorology issues Flood Warnings and River Height Bulletins for the Thomson, Barcoo Rivers and Cooper Creek regularly during floods. They are sent to radio stations for broadcast, and to local Councils, emergency services and a large number of other agencies involved in managing flood response activities. Flood Warnings and River Height Bulletins are available via :

Internet/World Wide Web

Telephone Weather

Interpreting Flood Warnings and River Height Bulletins

Flood Warnings and River Height Bulletins contain observed river heights for a selection of the river height monitoring locations. The time at which the river reading has been taken is given together with its tendency (e.g. rising, falling, steady or at its peak). The Flood Warnings may also contain predictions in the form of minor, moderate or major flooding for a period in the future. River Height Bulletins also give the height above or below the road bridge or causeway for each river station located near a road crossing. 

One of the simplest ways of understanding what the actual or predicted river height means is to compare the height given in the Warning or Bulletin with the height of previous floods at that location. 

The table below summarises the flood history of the Thomson, Barcoo Rivers and Cooper Creek basin - it contains the flood gauge heights of the more significant recent floods.

Historical flood heights for all river stations in the Thomson, Barcoo Rivers and Cooper Creek Floodwarning network, as shown on the map, are available from the Bureau of Meteorology upon request

Flood Classifications

At each flood warning river height station, the severity of flooding is described as minor, moderate or major according to the effects caused in the local area or in nearby downstream areas. Terms used in Flood Warnings are based on the following definitions.

Major Flooding : This causes inundation of large areas, isolating towns and cities. Major disruptions occur to road and rail links. Evacuation of many houses and business premises may be required. In rural areas widespread flooding of farmland is likely. Moderate Flooding : This causes the inundation of low lying areas requiring the removal of stock and/or the evacuation of some houses. Main traffic bridges may be closed by floodwaters.  Minor Flooding : This causes inconvenience such as closing of minor roads and the submergence of low level bridges and makes the removal of pumps located adjacent to the river necessary.

Each river height station has a pre-determined flood classification which details heights on gauges at which minor, moderate and major flooding commences. Other flood heights may also be defined which indicate at what height the local road crossing or town becomes affected by floodwaters. 

The table below shows the flood classifications for selected river height stations in the Thomson, Barcoo Rivers and Cooper Creek catchment.   

All heights are in metres on flood gauges. 

(B)= Bridge (O) = Old bridge   (A) = Approaches  (C) = Causeway  (X) = Crossing  (d/s) = Downstream

The above details are correct at the time of preparing this document. Up-to-date flood classifications and other details for all flood warning stations in the network are at:

http://www.bom.gov.au/hydro/flood/qld/networks/index.shtml

Catchment Map showing the Thomson-Barcoo-Cooper flood warning network

For further information, contact:
The Regional Director, Bureau of Meteorology, GPO Box 413, Brisbane Q 4001