Landslide Input Entries

Dear Mr. Maeder,

There is one section in the program that I am still having problems with. It is the landslide section. The problem that I am having is determining the values for:

· Highest Top-Width Number of Landslide Mass
· Middle Top-Width Number of Landslide Mass
· Lowest Top-Width Number of Landslide Mass

I would appriate if you could explain in more detail these points.

I have been in contact with another company that uses DamBrk and they have a paper that was prepared by DL Fread entitled "The NWS DAMBRK Model Theoretical Background / User Documentation". I would like to know where this paper is availible from as it explains, in depth, most of the problems that I have been having.

Many Thanks
Justin Rookard
For CONSULTORES PICHI PICUN LEUFU UTE

Dear Justin Rookard :

The NWS DAMBRK Model Theoretical Background & User Guide is the original DAMBRK Reference Manual that we used to complete Chapter 6 of our BOSS DAMBRK User Manual. There is really nothing new in it. The remainder of the NWS DAMBRK document describes the card format for the NWS DAMBRK input file, as well as provide sample models and the output from these models.

The entries that you requested information on will be in our New BOSS DAMBRK User Manual that will be posted on our WWW site next week as a PDF document. There is other new items in the documentation as well. These entries define the number of the cross-section top-width entry where the landslide mass comes from. So, for example, if you had 5 top-width entries in and the Landslide started on the 3rd top-width entry on up to the 5th top-width entry, you would enter the following information:

Highest Top-Width Number of Landslide Mass 5
Middle Top-Width Number of Landslide Mass 4
Lowest Top-Width Number of Landslide Mass 3

If you have any additional questions or need any further information, please contact me again.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com

Dear Mr Maeder,

Thank you for your last Email and I successfully downloaded the new Dambrk User Manual at the weekend. I read the landslide section, regarding my problem that I am having with a new model. I have followed all the instructions from the manual and worked along side the example of a landslide analysis that came with the programe, but I still am not getting the results that I would expect. I have input the required sections upstream of the dam and made the inflow equal to the outflow. I have entered the required data for the landslide and results show no sign that a landslide has taken place. The reason for this analysis is to evaluate whether a landslides wave would be large enough to cause an overtopping failure. I can not understand why the results are like this. I have attached a copy of the Dambrk File so you can look at the work that has been done. I would appricate if you look at the model and offer a solution.

Many thanks
Justin Rookard
Pichi Picun Leufu

Dear Justin Rookard :

I have looked at your DAMBRK landslide model. It is defined as a steady state model, so the dam never fails and there is no landslide that occurs. You need to have the WSEL reach the elevation where you specified the dam failure would occur and then the landslide will be initiated. If you look at the output, the dam never fails nor does the landslide event ever occur.

Also, your landslide mass thickness of 500 meters is quite large. To get the model to run, I suggest reducing this. Also, the time of landslide failure is much too small, and can cause instabilities. You will need to lengthen this.

Note that there is a landslide example problem that is shipped with the software.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com