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state of affairs at Attabad, and NDMA have also posted online their statistics for 22nd May (note this is now two days out of date).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 occur
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ReplyDeleteHi Dave,
ReplyDeleteBundle of thanks for sharing your expert knowledge and educating people on this.
Cheers!
Hi Dave,
ReplyDeleteLooking at the pictures, certainly agree that the spillway is totally inadequate and the closing up of the side walls as well as the alarmingly deep erosion at the seepage points showed how weak these materials are.
To make the things worse, the gradient seems to be a bit too steep. I am certainly no expert in this field but taking the overall picture into account, my guess is that the spillway gives way within the first 2-3 hours or may be less.
However, further hiccough's could be added into this situation by collapse of side walls causing partial blockage to the flow resulting in basal erosion at a very rapid pace.
I am just hoping that side walls collapse though almost seems inevitable but may not result in any substantial blockage to flow and some how basal erosion could be prevented and resultantly downstream flooding wouldn't be as severe as could happen in the worse case scenario.
NDMA tried their bit but unfortunately it was too little too late. Now we just have to keep our fingers cross and wait and how this situation is going to unfold itself.
In the end, just couldn't thank you enough for taking such an interest in the situation and helping your readers and especially the people of Pakistan make an informed opinion about this whole scenario. Also thumbs up for the FOCUS team for collecting and collating all the very important data.
Regards,
Asif Khan
Thank you so much for your work on this. I am sure the people appreciate your efforts. God Bless and be safe. Let's just hope that a disaster does not occur and hope that the people affected may return to their homes soon. Kind Regards, K. C.
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