FLOOD WARNING SYSTEM
for the
NICHOLSON RIVER

Lawn Hill Creek at Lawn Hill

Contained in this document is information about: (Last updated June 2008) 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 Nicholson River catchment is located in north west Queensland and covers an area of about 53,200 square kilometres. The river rises on the Barkly Tableland in the Northern Territory, 300 kilometres northwest of the Camooweal. It flows in a general easterly direction, across the State border. The Gregory River, its major tributary, rises 50 kilometres east of Camooweal and flows in a northerly direction joined by the O'Shanassy River, just downstream of Riversleigh and Lawn Hill Creek, 70 kilometres downstream of Gregory Downs. The Nicholson River is joined by the Gregory River to the southwest of Burketown. The River finally passes through a vast open coastal plain before entering the Gulf of Carpentaria. Floods normally develop in the headwaters of the Nicholson and Gregory Rivers and its major tributaries, however, general heavy rainfall situations can develop typically from cyclonic influences which can result in widespread flooding, particularly in the lower reaches below Gregory Downs. 

The record major flood of March 1971 and to a lesser extent, the floods of February 1991 and 1993, caused widespread traffic disruption and inundation of  towns and properties throughout the lower reaches.

Previous Flooding

Previous flood information for the Nicholson River is limited. Peak heights are available since 1993 for most stations.

Flood Forecasting

The Bureau of Meteorology operates a flood warning system for the Nicholson River 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 a automatic telephone telemetry station at Gregory Downs.

The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins for the Gulf Rivers, including the Nicholson River, during flood events. Qualitative flood forecasts are issued when moderate flood levels are likely to be exceeded. 

Local Information

The Local Government is able to provide further information on flooding in your area of the Nicholson River catchment.

Flood Warnings and Bulletins

The Bureau of Meteorology issues Flood Warnings and River Height Bulletins for the Gulf River catchments, including the Nicholson River basin, 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 : 

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

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 Nicholson River basin - it contains the flood gauge heights of the more significant recent floods.

All heights are in metres.  [*] Height taken at old gauge site which may not relate to existing sites

Historical flood heights for all river stations in the Nicholson River 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 Nicholson River catchment. Note: All heights are in metres on flood gauges. 

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 Nicholson River flood warning network