Summary of current situation in the landslide at Attabad

This is a summary of the current situation with the landslide. Data correct to 11th May 2010 (10th May for NDMA data). Red indicates a rising trend from the previous reading and purple a falling trend. Orange numbers indicate no change. All data courtesy of Focus Humanitarian Assistance unless otherwise indicated. Please see notes of caution at the end of this post.

Please note that I am now calculating the date on which there will be flow through the spillway using the rate of increase for the last 24 hours. This is because the rate of increase in water level is now increasing quite quickly.

Current estimated date on which water will start to flow through the spillway:
Estimate based on current (24 hour rate) of increase of water level: 25th May 2010

Water flow through the spillway may occur sooner than this date.

Depth of lake (NDMA data) : 95.45 m (10th May)
Depth of lake (Focus data): 98.38 m
Freeboard (Focus data): 12.11 m
Length of lake: 15.80 km
Rate of inflow: 67.50 cubic metres per second (last measurement = 4th May)
Total seepage (NDMA data): 1.70 cubic metres per second (10th May)
Total seepage (Focus data): 2.05 cubic metres per second

Average rate of decrease of freeboard over the last 24 hours: 83.84 cm per day
Number of days to water flow at current rate of freeboard loss: 14 days

Estimated date of water flow through the spillway based on rate of loss of freeboard for last 24 hours (see note below): 25th May 2010. Actual flow may occur earlier than this date.

Important: The calculation of days to water flow through the spillway is subject to substantial uncertainty and must not be used for planning purposes. The rate at which the lake fills changes considerably with time according to variations in the rate of inflow, the rate of seepage, the rate of excavation of the channel, the shape of the valley etc. Under some circumstances, such as an earthquake, a landslide into the lake or rapid piping failure flow could start earlier.
Posted by Dr Dave at 5:27 PM 1 comments
Labels: Attabad, Hunza, landslide dam, Pakistan
Seepage at the landslide dam at Attabad in Hunza
Latest update: 12th May 2010 using data up to 11th May 2010