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This brochure describes the flood warning system operated by the Australian Government, Bureau of Meteorology for mainstream flooding along the Balonne and Maranoa River catchment downstream of Cotswold. 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.
The Flood RiskThe Condamine-Balonne River system is one of the major tributaries of the Murray-Darling River system and is one of the most important river systems in Queensland in terms of agriculture. The headwaters of the Condamine-Balonne River rise in the Border Ranges upstream of Killarney and flow for approximately 1200 kilometres through Queensland before entering New South Wales. Major floods do not necessarily develop in the headwater areas of the catchment but can result from heavy rainfall in any of the large tributaries which enter the main Balonne River. In 1990 the Maranoa River experienced a major flood which extended to the NSW border. However, there was no significant flooding in the main Balonne system. Under these circumstances flood forecast lead times may be shorter than the typical 2 to 3 days. The most significant effects of flooding along the Balonne River are the widespread inundation of agricultural land, the isolation of rural homes and properties and the loss and damages suffered in these areas. Damage to fencing, pumping equipment, machinery and loss of stock through drowning result in significant losses during major floods. Previous FloodingRecords of large floods along the Balonne River extend back as far as 1890 at St. George with extensive records at several other locations on the main stream. Major floods typically occur on average every 2 years. Major flood events were recorded in 1942, 1950, 1956, 1975, 1976, 1983 (twice), 1988 and 1996. The record major floods in March 2010 and January 2011 produced widespread inundation and traffic disruption. Whilst the January/February flood event of 2012 may not have been as significant on the Balonne River upstream from St George it produced record flood levels at St George, Roma (Bungil Creek) and Mitchell (Maranoa River) and inundated large residential areas.
Flood ForecastingThe Bureau of Meteorology operates a flood warning system for the Condamine - Balonne River catchment downstream of Cotswold based on a rainfall and river height observations network shown on the map. The flood warning network consists of a number of volunteer rainfall and river height observers, as well as automatic telephone telemetry station's located throughout the catchment, which are operated by the Department of Natural Resources, Mines and Energy. The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins for the Condamine - Balonne River catchment downstream of Cotswold during flood events. Quantitative forecasts are issued whenever river heights are expected to reach minor flood levels at Warkon, Surat, Warroo, St George, Dirranbandi and Hebel on the main river, Mitchell, Springfield and Woodlands on the Mitchell River and Roma on Bungil Creek. Local InformationLocal Council's throughout the Condamine - Balonne River catchment downstream of Cotswold are able to provide further details of flooding in your area. Flood Warnings and BulletinsThe Bureau of Meteorology issues Flood Warnings and River Height Bulletins
for the Condamine - Balonne River downstream of Cotswold 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. 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 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 Condamine - Balonne River catchment downstream of Cotswold - it contains the flood gauge heights of the more significant recent floods.
All
heights are in metres on flood gauges. Historical flood heights for all river stations in the Condamine - Balonne River catchment downstream of Cotswold 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 Condamine - Balonne River catchment downstream of Cotswold.
All heights are in metres on flood gauges. (B) = Bridge (C) = Causeway 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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