|Queensland floods: Ipswich revisited - maandag 17 januari 2011|
Simulation model v.s. reality
In January 2011, Queensland underwent severe floods. Because I have lived and worked in Australia during the whole year 2004, I thought it would be interesting to compare some of the results of my projects back then with the extents of the actual floods.
My most interesting project in 2004 involved Bundamba Creek in Ipswich, just east of Brisbane. In January 2011 this area actually flooded as can be seen in the aerial photograph below. In the news this event was said to have been a T=50 flood, which means that these water levels are expected to be exceeded on average approximately once every 50 years.
Although there are a lot of similarities between the simulation results and the actual flood extents, it is not really fair to compare the results. First and foremost, the Brisbane floods encompassed the entire catchment of the downstream Bremer river, whereas my project only involved extreme rainfall upstream from the project area.
Secondly, the simulation represents a once per 100 years situation whereas the actual flood is said to have a Recurrence interval of 50 years.