This blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings. The blog is written on a personal basis by Dave Petley, who is the Wilson Professor of Hazard and Risk in the Department of Geography at Durham University in the United Kingdom.

This blog is a personal project that does not seek to represent Durham University.

Friday, 18 June 2010

River flows at Attabad

Thanks to Dr David Archer of the University of Newcastle for an analysis of the dates of peak flows on the Hunza.  The analysis is for Danyor (sometimes spelt "Dainyore"), which is near to Gilgit downstream of Attabad (there is no hydrograph data for Attabad itself), but it provides a clear insight into the current vs maximum flow in the river.

  Danyor (Dainyore) Bridge (from here)

This table shows the mean date of occurrence in the season of specific percentages of the peak flow based on the 33 year period from 1966 to 1998:

Flow                         Mean date                                 Standard Deviation (days)
Peak                         29th July                                   14
50% of peak             26th June                                  11
20% of peak             3rd June                                    9
10% of peak             18th May                                  11
5% of peak               2nd May                                    9

This suggests that on average the current flow would be somewhere between 20% and 50% of the peak summer flow - i.e. that the spillway is going to have to cope with a great deal more water yet this summer.  Assuming that the data are described by a normal distribution, we would expect that in 68% of years (representing 1 standard deviation) the peak flow would occur within 14 days of 29th July (i.e. between 15th July and 12th August.

6 comments:

tropical said...

"Assuming that the data are described by a normal distribution..."

But we know that it's not normally distributed. It's negatively skewed; the negative skew is a result of glacier melt and runoff rates.

tepui said...

"the peak flow would occur within 11 days of 29th July (i.e. between 18th July and 9th August."
A little mistake - according to the table it should be:
"the peak flow would occur within 14 days of 29th July (i.e. between 15th July and 12th August.

In general - your blog is a great site.

Brigadier (retired) Samson Simon Sharaf said...

So what does the future hold?

Divalent said...

Apparently the gov has decided to take active steps to widen the spillway.

http://www.apakistannews.com/plan-underway-to-widen-attabad-spillway-190383

Not much detail about when and how.

Anonymous said...

According to PamirTimes a deal has been struck between the villagers who worked to enlarge the spillway and the agency in charge called NDMA:

The agency has promised to blast some boulders that obstruct the flow within ten days of the agreement. If it fails to do so the villagers will resume their attempt to widen the spillway by their own means.

Khamomil

Anonymous said...

A Local Newspaper says boulder has started sliding a little and hence decision about blasting has been delayed for two days.