Situation as per 25th June:
Lake depth: 116.7 metres
Change in lake depth in last 24 hours: +0.13 metres (negative number = fall in lake level)
Spillway discharge: 352 cubic metres per second
Estimated seepage: 6 cubic metres per second
Estimated total outflow: 358 cubic metres per second
Estimated total inflow: 419 cubic metres per second
Lake level graphs:
Lake level and rate of filling from time of landslide:
Lake level since 21st May 2010:
Flow through the spillway:
Thank you for these graphs.
ReplyDeleteThe need for a spillway is still not clear to me, except for the fact that it is helping in spillover many days/weeks earlier than it would have otherwise happened. Secondly, what would be interesting to see is a reference table comparing mean flow on the hunza river in june and july every year, and the qty of water in the lake. A comparison showing how many times would the outflow increase over and above the standard june/july outflow and how many days that would take to drain the lake would be interesting.
ReplyDeleteTo clarify further, the spillway other than earlier spillover, is actually cutting through the dam thus increasing the chances of a sudden breach. A spillover the entire dam surface, or larger portion of it, would have triggered a more spread out and thus more gradual erosion. Please clarify this. Also is it right to say that after the completion of the spillway, the downstream face of the spillway should have been reinforced with pebbles/rocks/and maybe a layering of concrete.
ReplyDeleteThe suggestion regarding controlled blast of the rock blocking the spillway channel, is it possible to actually dig a route around the rock on the slope side. This, if possible, would help avoid blast related hazards and other rocks falling into the channel. Also please specify if possible, what maximum amount of surplus outflow, over and above the standard june/july outflow, would just about prevent any villages downstream from being flooded. This would be something of a threshold point.
ReplyDeleteAs ever thankyou Dave and Focus for the continuing commentary.
ReplyDeleteSurely the inflow into the lake is increasing with increasing seasonal temperatures? If so, I do not understand how the flow through the spillway appears to be decreasing. I thought the erosion on the depth of the spillway was faster than the reduction in depth of the lake.
Does it mean that there is additional debris blocking the spillway either from new avalanches or blockages caused by the weathering from the banks blocking the channel?
I understood the best outcome is a slow release of the water through a gradually incremental erosion of the spillway. Clearly these blockages, if they are the cause for the will hamper that outcome.
many thanks for your continuing work
Thank you, Dave for all of your reports. About 20 years ago I was offered the opportunity to write my PHD in cultural Anthropology on the effect the Karakoroum Highway had on the people in the Hunza valley. Althought I could not take up the opportunity for personal reasons the people in the area have stayed close to my heart. Ever since I heard about the landslide I followed the news on it. I prayed for the people in the area and for wisdom for all who are involved in the process of trying to prevend further catastrophies. Thanks for all the updates.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThe outflow should read 358 cu m/s.
ReplyDeleteThe situation is very worrying. Please get some photos of Passu and areas beyond.
The valley beyond Passu gets constricted and then the rise in water level will be phenomenal.
Your comments and opinion are a valuable source of information re this situation.
ReplyDeleteI am not aware of any 'reaction' in the national news media.In fact most,if not all, channels have forgotten about this.
Pl keeps us informed re the different options available to resolve this difficult issue.
jehangir rehman
And yet we do want our car to be admired by others Birth Forumgalway hotels
ReplyDelete