27 September 2012

Exceptional erosion undercuts an apartment block in the UK

Posted by Dave Petley

Resuming the spell of exceptional rainfall from the early summer in the UK, northern England has been affected by an unusually intense low pressure system over the last two days, bringing unusually heavy rainfall.  Worst affected has been my home area, NE England, with extensive flooding and at least some landslides.  Perhaps the most interesting event appears to have been unusually intensive erosion associated with very high stream flows in the Newburn area of Newcastle-upon-Tyne.  In particular, a set of modern apartments have been affected by intense erosion, leaving them in a precarious position supported only by the piles that formed their foundations:

The BBC have a really good video of the site from the air, which is much more dramatic than the above image:

See also the slideshow here.

The Chronicle reports that these flats have been suffering problems since the rains in the early summer, and were initially evacuated in June.  The suggestion is that it is the failure of the culverts to handle peak flows that is responsible for the problem (I have no way of knowing if this is the case).  The pipes that are visible above suggests that measures were being taken to try to deal with flooding.  However, the Google Earth imagery from March 2012  summer 2012 [ correction as it is likely that the imagery date is incorrect] of the site shows multiple pipes in place in the area around the flats, perhaps suggesting that the problems may have been occurring for a while.:

Managing water is such situations is critical.  Once water starts to erode loose material, such as fill, then the process is difficult to arrest.  This was displayed beautifully by this culvert failure from the US in 2009.

It would be interesting to know what has been going on in the culvert and in the catchment upstream, and whether the flats were built on fill.  That the piles continued to support the building through this level of erosion is quite impressive.