4 June 2010
Focus have kindly provided a new set of images of the situation at Attabad with respect to the spillway. I think that these images were taken yesterday.
Most importantly, here is an overview image of the spillway:
It is helpful to compare this with the image of the spillway from 1st June (right hand image):
It is clear that the situation has developed considerably over the last few days. The flow along the spillway has increased greatly, and the lower part of the channel has widened and deepened. Flow appears to still be controlled by the large boulder in the middle of the channel, although the lowering of the channel downstream will be steadily undercutting this.The development of the spring on the channel edge is also interesting.
A closer view of the spillway clearly shows how widening is occurring:
The flow is undercutting the banks, which are then progressively failing. Note also just how much scour is occurring even though the bed of the channel is boulder-strewn – it is clear that at the moment the boulders are not armouring the channel.
A view from the downstream side of the channel is fairly dramatic:
This gives the impression that there is a huge volume of water flowing. However, a look downstream towards the old landslide deposit at Salmanabad (that is the big pile of debris upper right) shows that this is not really the case:
It is clear that the flow is still rather modest, despite the huge amount of erosion that the water has achieved.