Floodplain Manager June 2019


A recent study by Oxford University estimates that about a quarter of the world’s land transport infrastructure is exposed to at least one hazard and about three quarters of the damage to it from natural hazards is caused by flooding.  This is not surprising given that road and rail lines are built to cross rivers and mountains.  I am sure that if we were to estimate the damage to dam and sewerage infrastructure that it too would be highly susceptible to flooding given where it must sit in the landscape.  But what of other critical infrastructure such as energy and communications infrastructure where there is more discretion on where it is located?

This was an issue I explored in the paper I gave at the recent Floodplain Management Australia (FMA) conference and has been a particular interest of mine since I began looking at flood damages in 1991.  So often infrastructure design is driven by meeting a predetermined flood standard (usually the 1% AEP) without any consideration of the consequences of that level being exceeded.  A pad mounted electricity transformer which supplies a few streets is often designed to the same standard as a zone substation which supplies a suburb or a transmission substation which supplies several zone substations.  Yet a pad mounted transformer is easy to replace, only a few premises lose their power for a short time and many of them have been vacated due to flooding in any case.  A transformer in a transmission substation on the other hand is more difficult to repair and replace and many of the premises which will be without power are not directly affected by the flooding.  A genuine risk based design process needs to be followed for such important infrastructure.  This highlights a poor perception of risk, even in professions such as engineering where it should be better understood.

Many of this month’s articles can be seen through the lens of poor risk perception.  Whether it be coastal communities who think sea level is rising but it won’t affect them, small businesses who fail to take out flood insurance or international airports which are constructed just above current high tide levels.  Then there are the articles which report on efforts being made to better communicate flood risks in one way or other from the publishing of masses of flood insurance data in the US to targeted teaching of UK school children through to the applied research on flood communication done by Australia’s Bushfire and Natural Hazards Cooperative Research Centre.

I trust you can glean more ideas from this issue to better manage flood risks in your patch of the world.


Steven Molino


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