The Rain Threat !

Last year we had the hottest summer on record and this winter has been unusually mild.  The usual  end of a hot day in Australia is a thunder storm.  They are spectacular, but we mostly regard them as harmless.

 This rise in heat has produced a new phenomenon that has attracted attention on a world wide basis.  It is now delivering what is being called the " Flash Flood ".  The intensity of those thunder storms  concentrates the water delivered to a small section of the earth beneath to such an extent that there are landslides, intense flooding that sweeps away cars and houses - and people.  This is the destruction that we view on our television screens when nature delivers one of these flash floods on an unprepared community.

That has always been an eventuality, but now it is becoming more common.  We are living in a warmer world and there is the expectation that it will warm further still in the years ahead.  We need to take this into account in the way we build houses and in the planning of new estates to ensure that wastewater systems can clear this water and avoid it becoming a major flood descending on those living at lower levels.

Unfortunately, the engineering standards we are using were calculated before world warming became a new threat.  It has long been understood that the atmosphere contains about 6.5 percent more moisture per degree of temperature, but that is magnified by the storm intensity.  The fury of the storms we are seeing is now dropping a greater degree of intense rain in concentration to a smaller area below.

The demand for new housing is seeing new estates established on flood plains and new housing standards needs to apply.  Building a single level home on a slab almost guarantees a flood in the event of a flash flood event.  That would be better served by the living quarters on the upper level and the grounds floor reserved for garage parking and play areas.

More attention needs to be given to waste water disposal.  The damage from a flash flood can be mitigated if the drains are capable of quickly handling that excess water and limiting the damage.  Even  a small amount of water penetrating homes ruin carpet and destroy furniture, and usually this is not covered by insurance.  Cleaning and repairing a flood damaged home is a miserable experience.

Global warming has been a divisive issue.  There seems to be no doubt that the ferocity of thunder storms has increased and this flash flood phenomenon has become a reality.  Due to its intensity, there is now no such thing as a " flood free area ".  Our engineering standards urgently need an upgrade to accommodate this new reality.