24 May 2010

24th May update on Attabad (post now complete)

Posted by Dave Petley

FOCUS have kindly provided an update on the state of affairs at Attabad, and NDMA have also posted online their statistics for 22nd May (note this is now two days out of date).  The freeboard graph looks like this:

Key points:
1. The Focus data (which has consistently been the most reliable) indicates a freeboard of 1.15 metres on 23rd, with the water level increasing at about 80 cm per day, giving a likely overtopping date of today or tomorrow.
2. However, the NDMA data gives a freeboard 60 cm higher than Focus on 22nd May, and a lower rate of water level rise (48 cm in 24 hours).  If this is correct, overtopping will occur later in the week.

Seepage continues to increase, but a seepage-induced failure now looks unlikely in the context of loss of freeboard.  Focus have provided some images of the situation taken from their monitoring point.  Before I show these, I do want to make the point that the Focus team have provided an exceptional service to the people of Hunza, and indeed of Pakistan, as well as to readers of this blog.  They have done so iin extraordinarily difficult conditions.  This is the text and monitoring point in which they have been living for the last two months:

The mast is the CCTV station.  We have all benefited from the information they have provided – I hope that comments on this post will reflect this extraordinary effort and contribution, and that in due course the people of Pakistan will recognise what they have achieved.

The team have provided this image of the site looking down from this monitoring point:

This is a view from the monitoring point looking down onto the dam site, taken yesterday by Focus:

My concern about the state of the spillway is increasing.  This image shows the spillway from the same point:

The spillway looks in a fairly poor state in the image above.  However, the image posted today on the Pamir Times is even worse:

It is clear that the sides of the spillway have closed up over the last few weeks, leaving a narrow channel that is almost totally inadequate.  The weakness of the materials also bodes ill for events when over-topping occurs.