Update 5: 19th April 2010 at 16:00 UT
This is a summary of the current situation with the landslide.? Data correct to 18th April 2010.? 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.
New information: The rate of decrease of freeboard is accelerating.? The latest estimated date of overtopping is 19th June 2010 (see notes below)
Depth of lake (NDMA data) : 80.12 m
Depth of lake (Focus data): 82.24 m
Freeboard (vertical distance between lake level and base of spillway): 28.34 m
Length of lake: 12.08 km
Rate of inflow: 30.62 cubic metres per second
Total seepage (NDMA data): 0.66 cubic metres per second
Total seepage (Focus data): 0.90 cubic metres per second
Average rate of decrease of freeboard over the last ten days: 45.67 cm per day
Number of days to over-topping at current rate of freeboard loss: 62 days? (see note below)
Estimated date of over-topping based on rate of loss of freeboard for last ten days (see note below): 19th June 2010
Important: The calculation of days to over-topping 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 the dam could fail prior to overtopping.
