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This brochure describes the flood warning system operated by the Australian Government, Bureau of Meteorology for Myall Creek to Dalby. 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.
Flood RiskThe Myall Creek catchment to Dalby drains an area of approximately 1375 square kilometres, extending from the Great Dividing Range towards the town of Dalby and the Condamine River. The main branch of the creek rises beneath Mt Mocatta, which is located north of Maclagan, whilst Cain Creek/Spring Creek tributary of the main branch extends eastwards towards Haden. The north branch of Myall Creek rises beneath Mt Mowbullan in the Bunya Mountains. Myall Creek joins the Condamine River just downstream of Loudoun Bridge on the Moonie Highway. The town of Dalby lies in the floodplain of Myall Creek, both the town and the surrounding agricultural community suffer extensive damage during major floods. Previous FloodingMyall Creek has records of floods dating back to 1908 with 11 major flood events having occurred since this time, the highest being the February 1981 flood which rose to a height of 4.50m on the flood gauge located in Patrick Street. This resulted in some 700 homes and 140 businesses being inundated by floodwaters and some 25,000 ha of agricultural lands suffering moderate to severe flood damage. Four large floods were recorded through Dalby during December 2010 and January 2011. The largest flood (3.74 metres) was the 5th highest on record dating back to 1942. The figure below shows the significant flood peaks which have occurred at Dalby since records began.
Flood ForecastingThe Bureau of Meteorology and the Western Downs Regional Council jointly operate an AERT flood warning system for the Myall Creek catchment. The system comprises a number of rainfall and river height stations that automatically forward data via radio telemetry to a base station at the council offices in Dalby and to the Bureau's Flood Warning Centre in Brisbane. The system provides early warning of heavy rainfall and river level rises and enables more accurate and timely flood warnings. The network also consists of a number of volunteer rainfall and river height observers who forward observations by telephone or online when a defined initial flood height has been exceeded at their station. The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins whenever the creek height is expected to exceed the minor flood level at Dalby. These warnings are updated several times per day throughout a flood event. Local InformationThe Western Downs Regional Council is able to provide further details of local flooding in the rural areas of the Myall Creek catchment as well as residential areas of Dalby. Flood Warnings and BulletinsThe Bureau of Meteorology issues Flood Warnings and River Height Bulletins for the Myall Creek catchment to Dalby 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 Local response organisations Internet/World Wide Web Telephone Weather
Interpreting Flood Warnings and River Height BulletinsFlood 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 river height predictions for Dalby. 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 Myall Creek catchment to Dalby and contains the flood gauge heights of the more significant floods.
All heights are in metres on flood gauges. Historical flood heights for all river stations in the Myall Creek catchment to Dalby as shown on the map, are available from the Bureau of Meteorology upon request.
Flood ClassificationsAt 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.
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 Myall Creek catchment to Dalby.
All heights are in metres on flood gauges. (B) = Bridge (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: For the latest rainfall and river height conditions please use the following link: Latest rainfall and river heights For the latest rainfall and river height network map please use the following link: Network
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