17 May 2010
The rate of seepage at the Attabad landslide is now increasing at a rapid rate, and a new seepage point emerged in the last 24 hours. This graph shows the seepage rate since the start of monitoring:
The current rate of increase does pose the risk of a seepage-induced failure. This is not inevitable, but the risk is increasing with time. The authorities need to be prepared for the possibility that seepage could develop very rapidly indeed. The most recent Focus update provided an image of the two main seepage points:
The one below the spillway is the one that developed at the end of last week – yesterday this was discharging about 1 cubic metre per second. To the right is the main seepage point – yesterday this was producing 2.8 cubic metres per second. Note how much erosion these seepage points have generated in the channels they have cut. This does not bode well.