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This brochure describes the flood warning system operated by the Australian Government, Bureau of Meteorology for the Nebine, Mungallala and Nebine Creeks . It includes reference information which will be useful for understanding Flood Warnings and River Height Bulletins issued by the Bureau's Flood Warning Centre during periods of high rainfall and flooding.

Wallam Creek at Homeboin Wallam Creek at Homeboin
Contained in this document is information about:
(Last updated May 2011)

Flood Risk

The Nebine, Mungallala and Wallam Creek catchments are located about 100 to 150 kilometres west of St George in southwestern Queensland and drain an area of approximately 36,000 square kilometres. Mungallala Creek rises in the Chesterton Ranges 50 kilometres northwest of Mitchell. The Nebine and Wallam Creeks rise in an area south of a line between Mitchell and Morven. The small townships of Bollon and Mungallala are the only towns in the catchment.

All three creek systems flow in a southerly direction, parallel to each other for some 250 to 300 kilometres, before crossing the Queensland and New South Wales border west of the town of Hebel. They join the Culgoa River prior to entering the Darling River system upstream of Bourke. 

Floods normally develop in the headwaters area of Nebine, Mungallala and Wallam Creeks. However, general heavy rainfall situations may occur throughout these vast catchments. In recent years, the catchments have seen extensive flooding particularly in May 1983, April 1990, February 1997 and in March 2010. The flood of March 2010 produced large scale traffic disruption and residential area inundation. There were also localised communities that required evacutation.

Previous Flooding

Previous flood information for the Nebine, Mungallala and Wallam Creek catchments are well documented, with river height records for Homeboin and Tomoo dating back to the 1950's. The record major flood of March 2010 caused widespread traffic difficulties and property inundation.

Highest Annual Flood Peak Diagram

Highest Annual Flood Peak Diagram

Flood Forecasting

The Bureau of Meteorology operates a flood warning system for the Nebine, Mungallala and Wallam Creeks 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. 

The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins for the Nebine, Mungallala and Wallam Creeks during flood events. Qualitative flood forecasts are issued when moderate flood levels are likely to be exceeded. 

Local Information

Local Council's throughout the Nebine, Mungallala and Wallam Creek catchments 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 Nebine, Mungallala and Wallam Creek catchments 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 : 

Radio stations, particularly the local ABC, and local commercial stations, broadcast Flood Warnings and River Height Bulletins soon after issue. 

Local response organisations
These include the Councils, Police, and State Emergency Services in the local area. 

Internet/World Wide Web
Flood Warnings, River Height Bulletins and other weather related data is available on the Bureau's Web page at http://www.bom.gov.au . The Queensland Flood Warning Centre website is http://www.bom.gov.au/qld/flood .

Telephone Weather
Flood Warnings are available through a recorded voice retrieval system, along with a wide range of other weather related and climate information.

Main Directory Phone 1900 955 360
Flood Warnings Phone 1300 659 219

Telephone Weather Services Call Charges:
1900 numbers: 77c per minute incl. GST; 1300 numbers: Low call cost - around 27.5c incl. GST.
(More from international, satellite, mobile or public phones)

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 Nebine, Mungallala and Wallam Creek catchments - it contains the flood gauge heights of the more significant recent floods.

River height station
Homeboin 3.91 3.60 3.90 4.00 4.15 4.70
Bollon 1.35 1.53 1.44 1.47 0.99 1.76
Mungallala - - - - - 2.90 4.50
Tomoo 6.40 4.30 4.70 6.75 6.10 5.00 8.30
Deelamon   3.20* 3.85* 6.15 5.90 3.85 6.70
All heights are in metres on flood gauges. 
[*] These heights are taken at old gauge sites and may not relate to flood levels from existing gauge sites

Historical flood heights for all river stations in the Nebine, Mungallala and Wallam Creek catchments Floodwarning network, as shown on the map, are available from the Bureau of Meteorology upon request.



Major flooding requires a large scale rainfall situation over the Nebine, Mungallala and Wallam Creek catchments.  The following can be used as a rough guide to the likelihood of flooding in the catchment :

Average catchment rainfalls in excess of 25mm, with isolated 50mm falls, in 24 hours may result in stream rises and the possibility of minor flooding and local traffic disabilities. If rainfalls have been recorded in the previous 2 to 3 days, then moderate to major flooding may develop.

Average catchment rainfalls in excess of 50mm, with isolated 75 to 100mm falls, in 24 hours may result in significant stream stream rises with the possibility of moderate to major flooding developing, particularly in the lower reaches of all three catchments and extending downstream to the Queensland and New South Wales border. 

Flood Classifications

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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 Nebine, Mungallala and Wallam Creek catchments.  

River Height Station
First Report Height
Crossing Height
Minor Flood Level
Crops & Grazing
Moderate Flood Level
Towns and Houses
Major Flood Level
Homeboin 0.5 0.50 (X) 2.0 2.5 2.5 3.5 3.0
Bollon 0.4 0.60 (C) 0.5 0.7 1.0 1.0
Mungallala 2.0 4.20 (B) 3.0 4.0 4.5
Tomoo 0.5 2.0 6.0 5.0 6.9 6.0
Deelamon 0.3 0.20 (X) 1.0 2.0 2.0 3.5
Bendena 0.5 1.0 2.0 2.0 3.0 3.0

All heights are in metres on flood gauges.

(B) = Bridge  (C) = Causeway  (X) = Crossing

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:


Catchment Map showing the Nebine, Mungallala & Wallam Creek flood warning network

Click here to view map as:          PNG           PDF(410K bytes)

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