24 August 2011

New satellite images of the Attabad landslide site

Posted by Dave Petley

The NASA Earth Observatory, via the EO-1 satellite team, have kindly collected a new image of the Attabad dam site in northern Pakistan, and have made the images available.  In the last few weeks there has been little solid information about the state of the dam, although in Pakistan the violent response by the authorities to a demonstration by displaced people, which resulted in the deaths of two men, has been a major news story.

This new image was collected early this month (3rd August) using the EO-1 satellite.  The data have been processed into two products – a true colour composite (which resembles an aerial photograph):

And second a SWIR image, which highlights the difference between land and water:

Of course the most interesting aspect is the evolution of the spillway.  The image below shows this area on the TCC image:

Compare this with an image collected by the same instrument in early June:

There is noticeably more flow through the spillway than in the earlier image, and there appears to have been some downstream erosion through widening of the channel.  However the flow is still being controlled by the narrow section at the dam crest, which appears to have undergone little change.

Summer is now almost over in this part of northern Pakistan, such that flows will start to reduce again in the next few months.  It will be interesting to see whether the government uses this coming winter to reduce the height of the dam.