23 October 2014

Riverbank collapse: a fascinating new video

Posted by Dave Petley

Riverbank collapse

Riverbank collapse is a type of landslide that has probably been under-researched in recent years.  Whilst such events cause few fatalities in the global scheme, the impact on infrastructure and property can be serious.  A fascinating case study lies in the Mekong River – a problem that is so serious that in 2009 the Prime Minister of Cambodia warned about the threats of the “seasonal collapse of riverbanks”.  Earlier this year a woman and two young children were killed by riverbank collapse in Kandal Province in Cambodia.  This image, from the same article, is a nice illustration of the problem:

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Over in Australia there is a very nice project in progress, in which I have some involvement, looking at riverbank collapse along the Murray River, where collapsing riverbanks were a major problem when the river level was very low in the drought of a few years ago.   There is a very nice e-poster by the research team online explaining the provisional results of this work  – NB this is a pdf.

Whilst the mechanisms of riverbank collapse might initially seem to be simple, they are in reality extremely complex, not least because the stress state is very dynamic due to the effects of water coming into the bank from the river, from the bank top and through the ground.  In many rivers water levels rise and fall quickly, causing unusually rapid pore water pressure changes.  And of course humans have an annoying habit of messing around with rivers, and riverbanks, too.

Anyway, there is an interesting video on Youtube, which I don’t think I’ve seen before, showing a riverbank collapse event.  I am not sure where this happened.

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Clearly the river is in flood, but the complexity of the failure, and its progressive nature, illustrates how complex the mechanics can be.