FLOOD WARNING SYSTEM
for the
MULGRAVE AND RUSSELL RIVERS

This brochure describes the flood warning system operated by the Australian Government, Bureau of Meteorology for the Mulgrave and Russell Rivers. 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.

Downstream from Peets Bridge

Contained in this document is information about: (Last updated May 2011) Flood Risk Previous Flooding Flood Warning Local Information Mulgrave/Russell ALERT System Flood Warnings and Bulletins Interpreting Flood Warnings and River Height Bulletins Flood Classifications Catchment Map

Flood Risk

Previous Flooding

The Mulgrave and Russell Rivers have a quite well recorded flood history with documented evidence of flooding beginning in the late 1930's. Records at the key reference gauge at Gordonvale show that the largest flood occurred in early 1967.

Flood Forecasting

The Bureau of Meteorology and Cairns Regional Council operate a flood warning system for the Mulgrave and Russell River catchments based on a rainfall and river height observations network shown on the map. In consultation with the Council,  the Bureau issues flood warnings whenever the Mulgrave River at Gordonvale is expected to exceed the minor flood level of 12 metres. The objective is to provide between 3 to 9 hours warning of flood heights exceeding this level. These warnings are generally updated every three hours.

Local Information

The Cairns and Tablelands Regional Councils may be able to provide further information on flooding in the area of the Mulgrave and Russell River catchment.

Mulgrave and Russell ALERT System

Flood Warnings and Bulletins

The Bureau of Meteorology issues Flood Warnings and River Height Bulletins for both the Mulgrave and Russell River 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.

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 Mulgrave and Russell River catchments - it contains the flood gauge heights of the more significant recent floods.

All heights are in metres on flood gauges. 
[*] These heights are taken manually and from flood marks and may not relate to flood levels from existing gauges sites.

Historical flood heights for all river stations in the Mulgrave and Russell 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. 

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 Mulgrave and Russell River catchment.

Catchment Map - Mulgrave and Russell River flood warning network

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