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30 May 2010
Retrogressive erosion at Attabad
Flow continues to increase at Attabad. Inflow is still exceeding outflow and seepage, so the lake level continues to rise, to the detriment of the upstream communities. There has been some confusion about the statistics about outflow – it is now clear that NDMA discussions often use the combined spillway plus seepage figure, but that this is interpreted by the media as being the spillway flow. According to the NDMA …
Reported increases in spillway flow at Attabad
If you live in the Hunza and Indus valleys, please do not rely upon this blog to provide warnings and up to date information. Using only reliable reports in the media (mostly information from the Pamir Times) and those from NDMA, the following graph shows the reported flow through the spillway at Attabad. There is a huge caveat here regarding the reliability of the reports. However, the most recent figure …
Attabad – flow on the spillway continues to develop slowly
Flow through the spillway continues to increase slowly. So far there are no signs of the development of a breach, but the amount of water passing through the spillway remains much less than the inflow. This image, taken yesterday morning, shows water passing through the channel: The difference between the flow in the channel and the amount of water coming through the dam as seepage (the large channel bottom right) …
Attabad overtopping – first image
The Daily Times has published the first picture of the spillway in operation: Meanwhile, the Pamir Times reports that: “The volume of water passing through the spillway has reportedly increased to around 50 Cusecs”. 50 Cusecs is 1.4 cubic metres per second. This is still a fraction of the total inflow, so we have a long way to go.
29 May 2010
Attabad: initial flow established
Please note that it is hard for me to keep up to date with this evolving situation. If you are potentially-affected by this hazard please use the formal channels of communication set up by the government. Do not rely on this blog to provide warnings. Flow through the spillway is now properly established and is increasing with time. The latest NDMA report suggests that flow is 300 cubic feet per …
Attabad: overtopping has begun
The media are reporting that water has now “entered the spillway” – i.e. that overtopping has begun. The report, which is from the Chinese Agency Xinhua, carries a rather strange quote from an official from NDMA: “The next 12 hours could be crucial as the water flow would reach its maximum intensity,” commented an official of the National Disaster Management Authority (NDMA), the organization mainly responsible for the overall …
28 May 2010
Attabad: freeboard report 28th May
The media in Pakistan are reporting that the freeboard is now 2 feet (61 cm). Assuming that this was taken at the normal measuring time (i.e. 3 pm local time) the freeboard graph looks like this: Jean Schneider, who is on site and flew over the spillway today, reports that overtopping should begin overnight.
New images and maps of Attabad
Whilst we wait for news from Pakistan, here are two new resources that readers may find useful. First, NASA have released a new Aster image of the lake site, collected in the last few days. This is available here, with a link to my blog (thanks to them for this). The image shows the manner in which the lake has extended in the last few weeks – NASA have helpfully …
Attabad: Overtopping is now likely to be imminent
It is unfortunate timing that the likely day of overtopping has fallen on a Friday, the holy day in Pakistan, meaning that flow of information is impeded. As a result I have not yet had an update for today on the lake level. Jean Schneider of BOKU visited the site yesterday by helicopter and measured the freeboard at 2.25 feet, which is about 70 cm. I am not sure what …
27 May 2010
Attabad: the freeboard is now reportedly about 1,3 metres
The latest NDMA figures suggest that the freeboard is down to about 4.3 feet (1.31 metres) as of 3 pm today. That is a reduction of about 70 cm on the day, meaning that we are probably less than two days from the point of overtopping: I am reasonably confident of these values as the Focus geologists took this picture yesterday of the spillway: The circled boulder is the crest …
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
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