Disaster Planning & Flood Information

Flooding is a major cause of death in natural disasters. The Bureau of Metrology (BoM), Emergency Services, SES and Local Government all play a part in giving whatever advance warning and assistance is possible however the person who can do most to help is you.

As normal components of your household Emergency Plan, all residents should maintain an Emergency Kit and an Evacuation Plan to lessen the threat and impact of flooding. Flooding is a natural process that can happen suddenly, simple preparation can prevent enormous hardship to your family, self or business.

Flood Totem Poles

Colour banded poles have been painted in several locations within some low lying areas. The colour bands show the 2, 5, 10, 50 & 100 over year average recurrence interval (ARI) statistical flood levels as used in the Flood Maps website and Council's Planning Scheme. Flood level information supplied by flood maps and the Cassowary Regional Council is provided as a guide only.

The purpose of these poles to give simple visual representation of this data and inform and encourage residents in flood prone areas to develop and prepare their own household emergency plans.

Colour Banded Flood Totems and Community Awareness Project

Johnstone River Improvement Trust Jointly funded by: The Australian Government, Queensland Government and Cassowary Coast Regional Council.

Risk

The Johnstone River system comprises the North Johnstone River and the South Johnstone River with their confluence being at the town of Innisfail. From the confluence, the river flows about 5 km to the ocean. The rivers have a combined catchment of about 1600 km2 with the larger North Johnstone catchment being the around 1030 km2.

There is a history of severe flooding on the floodplain with considerable damage to property, agriculture and public infrastructure. Innisfail is most affected being at the confluence of the rivers and with development on flood prone land.

Flooding in and around Innisfail town occurs initially through backup of Saltwater and Sweeney's Creeks and then through overtopping of the banks around Innisfail and further to the north in larger floods.

Major flooding requires a large scale rainfall situation over the Johnstone River catchment and the information supplied on this website is to be used as a guide only to indicate the likelihood of flooding in the catchment area.

Average catchment rainfalls in excess of 200mm in 24 hours may cause stream rises with moderate to major flooding and traffic disabilities to develop, particularly in the lower reaches downstream of Nerada on the North Johnstone River and Corsis on the South Johnstone River extending to the coastal plain around the Innisfail township and the mouth of the Johnstone River.

Average catchment rainfalls of in excess of 300mm in 24 hours may cause significant stream rises with major flooding and traffic disabilities to develop, particularly in the lower reaches downstream of Nerada on the North Johnstone River and Corsis on the South Johnstone River extending to the coastal plain around the Innisfail township and the mouth of the Johnstone River.

Previous flooding

Severe flooding of the Johnstone River is often associated with tropical cyclones. The two highest floods at Innisfail in recent years occurred in February 1986 (1:20 ARI) and March 1967 (1:25 ARI). The flood records for Innisfail indicate that the highest recorded flood occurred in 1913 (1:100 ARI) and that it was about 1.5 metres higher than the 1986 flood. Historical evidence indicates that the floods in 1893 and 1894 were even higher.

Forecasting Interpreting warnings and river heights

The Council, in compliance with the Bureau of Meteorology operates a flood warning system for the Johnstone River catchment. The ALERT network consists of automatic rainfall and river height stations which regularly forward data via radio telemetry to a base station located at the Council offices in Innisfail and the Bureau's Flood Warning Centre in Brisbane. The system provides early warning of heavy rainfall and river rises in the catchment and enables more accurate and timely flood warning and forecasts. The balance of the network consists of volunteer rainfall and river height observers, who forward observations by telephone when the initial flood height has been exceeded at their station. The Department of Natural Resources also operates a number of automatic telephone telemetry stations throughout the catchment

The Bureau's Flood Warning Centre issues Flood Warnings and River Height Bulletins for the Johnstone River catchment during flood events. Quantitative flood forecasts are issued when moderate flood levels are likely to be exceeded at Innisfail, with an objective to provide between 3 and 9 hours warning of flood levels and forecasts updated every 3 hours during the flood event.

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 estimated height above or below the road bridge or causeway for each river station located near a road crossing.

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 Johnstone River catchment.

EVENT WITH PREDICTED GAUGE HEIGHT METRES
	Gauge Stations
	Johnstone	South Johnstone		North Johnstone
Events	Innisfail	Central Mill	Corsis	McAvoy Br	Tung Oil	Nerada
Crossing Height		3.9		7.1
Minor Flood Level	5.0	7.5	5.0	5.0	7.0	6.0
Moderate Flood Level	5.5	8.0	5.5	6.0	8.0	7.0
Major Flood Level	6.0	8.5	6.0	7.1	8.5	8.0
1:5 ARI	5.8
1:10 ARI	6.0	9.0	6.4		9.7	9.7
1:20 ARI	6.5	11	8.0		10.5	10.5
1:50 ARI	7.0	11.9	9.2		12	12
1:100 ARI	7.5	13.8	11.3		12.8	12.8
Possible Max Flood	12	16	13		17.3	17.3
Note	Innisfail Wharf Gauge Height 5m = 3m AHD

Euramo Bridge gauge Level 7.9m, Murray Flats 7.6m

Flood warnings and bulletins

The Bureau of Meteorology issues Flood Warnings and River Height Bulletins for the Johnstone River catchment 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

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 from the following links.

	The Australian Government Bureau of Meteorology
	The Queensland Flood Warning Centre

Major Flooding This causes inundation of large area's isolating towns and cities. Major disruptions occur to road and rail links. Evacuation of many houses and business premises will be required. Large economic loss to homes, business and crops. Moderate Flooding This causes the inundation of low lying areas requiring evacuation of some houses and the removal of stock and equipment. Road closures and loss of services can be expected. Minor Flooding This causes inconvenience such as closing of minor roads and the submergence of low level bridges. The raising of furniture etc. and relocating of vehicles may be required for homes in flood prone areas.

Flood Emergency Planning Resources

Queensland State Government, State Disaster Management Group - what you should do in the event of a flood.