Which of the following potentially affects the size of a flood? Trade winds blow strongly across the warm Pacific, picking up plenty of moisture and increasing the likelihood of above average rainfall in eastern Australia.Ħ. In a La Niña event, the equatorial ocean surface off the coast of South America is abnormally cool, and the SOI is strongly positive.

There is an increased chance of above average rainfall in eastern Australia.Ĭ.

The ocean surface off the coast of South America is warmer than usual.

The Southern Oscillation Index (SOI) is strongly negative.

Which of the following is associated with a La Niña event? Each of these variables can be measured using a river gauging station.ĥ. It can also be measured by the maximum water flow rate in a waterway, referred to as the ‘peak flow rate’ or ‘peak water flow’. The size of a flood can be measured by the highest level that water in a waterway reaches, referred to as the ‘peak water level’ or ‘flood peak’.

the level of water in a waterway or riverĭ.

the rate of flow of water in a waterway or river.

mean sea level) or an alternative arbitrary ‘zero’ level, depending on the location.

River height is the level of water in a river as measured by a river gauging station and is expressed in metres above either the Australian Height Datum (i.e. the water level is 10 metres above mean sea level or an arbitrary 'zero' levelĬ.the water level is 10 metres above mean sea level.the water level is 10 metres above an arbitrary ‘zero’ level.When a river’s water level reaches 10 metres, this means that: the total area under flood waters) of flooding can also vary.ģ. The volume, rate of rise and areal extent (i.e. The size, duration and water flow speed of floods can vary. While flash floods are often caused by heavy rainfall, they can also result from other events, such as drain blockages and bursts or the flooding of a river.ĭ. Flash floods are defined by the speed of flooding, not the source or location of flooding. occurs suddenly and unexpectedly and for a short durationĬ.is caused by heavy rain rather than from the flooding of a river.To learn more, read the Understanding Floods: questions and answers Test your knowledge with the floods quiz, 20 multiple choice questions on basic science and engineering concepts of floods, including flood causes and impacts, flood forecasts and warnings, flood management, and the impact of climate change and other factors on flooding in the future.

Areal flood definition