11 July 2011

Landslides and golf

Posted by Dave Petley

Perhaps the strangest landslide story of the month emerged from the Scottish Open Golf tournament over the weekend.  The tournament, which was held at the Castle Stuart course near to Inverness over the weekend, had to be shortened from 72 to 54 holes after torrential rain on Friday and Saturday left the course unplayable.  The  key event occurred on Friday night, when at least two landslides were triggered on the edge of the margins of the course.  The Guardian has the best images of the landslides – this is the one that attracted the most attention:-




Whilst this is the other:




There is a couple of things of interest to note here.  First, although it does not appear to be the case, the course is brand new, having only opened initially in the summer of 2009, and fully in 2010.  It is unclear how much earthworks were required to construct the topography, but the 2006 Google Earth image of the site, before the construction of the course started, seems to show pretty flat farmland:

For comparison, this is the course map as per the official website, rotated into the same orientation as above:

The second is the mobility of the first landslide, which has travelled a substantial distance.  Note that the terrain is clearly not flat, even on the lower slopes, but the slide does suggest that the material was in a quite liquid state (whilst still able to transport substantial gorse bushes).      This Guardian image, taken from the top of the slope, is quite instructive:




Note the way that the landslide has left coarser material behind on the slope and has built a levee on each side.  Finally, it appears that the flowing water after the slide has removed debris to form a channel down the centre of the slide, which reveals that the grass underneath is essentially undamaged.  All of this points to a shallow flow type event.

Unfortunately, I have not been able to track down an hourly rainfall record for the triggering event – anyone?

Incidentally, if you are interested the tournament was won by the British golfer and current world number one, Luke Donald.