9 February 2010

Problems at the Hattian Bala landslide dam in Pakistan

Posted by Dave Petley

The largest landslide in the 2005 Kashmir earthquake occurred at Hattian, 25 km or so from Muzaffarabad:

My colleagues and I wrote a paper on this landslide a few years ago (you can download the pdf here). It was notable for the fact that it blocked the valley – in the aftermath the Pakistan Army built a spillway to ensure that uncontrolled overtopping did not occur. The landslide has been stable since, although many of us have warned that this area is far from out of the woods, with the first really intense precipitation event being a key test.

In the last few days this area has suffered a very heavy rain and snowfall event – as in fact has a vast area of the Himalayan Arc – indeed I have never seen a 1 day TRMM landslide potential map like this – it is quite bizarre:

Late tonight, media sources in Pakistan are suggesting that the lake has broken its banks, flooding 23 houses. So far the dam is holding, but clearly this event will ask substantial questions of it. Hopefully, the spillway engineers have got this right!

Elsewhere in the Muzaffarabad area, heavy rain is reported to have triggered many landslides. I have not yet seen any reports of the situation at Attabad, but this is not likely to be helping.