Floodwaters

A NSW police officer rescued two women and a child from this vehicle that entered floodwaters in the NSW Hunter region in September 2022. Source: NSW Police Force (22 September 2022). [Facebook Page]. Facebook. https://www.facebook.com/photo.php?fbid=468224848683273&id=100064872844939&set=a.150708747101553&locale=ta_IN

There is a big difference between crossing a flowing creek or river and driving through floodwaters. A typical creek or river crossing will have the following characteristics:

• it will be relatively short and contained within the embankments

• because it is a watercourse the bottom is generally solid

• often the water is clear and you can see obstacles on the bottom.

Floodwaters, however, come with much more uncertainty:

• floodwaters are relatively more extended and not contained within embankments, meaning depth can vary greatly

• not being in a watercourse, floodwaters can very quickly undermine the structural integrity of sealed and unsealed roads, creating holes and washouts

• the water is murky and obstacles can’t be seen

• floodwaters will often carry debris such as logs and fallen trees, increasing risk.

UNSW research found that a 2.5 tonne 4WD in just 45cm of water - less than knee deep - has enough buoyancy to render it unstable. This is when you start to lose traction and, coupled with flowing water, can quickly lead to disaster. The same 4WD is able to be moved by hand in 95cm of water - check out the video below.

Water crossings and driving into floodwaters can be very different. If it’s flooded, forget it.