elevation of water when failure of dam commences

[emilias]

I am trying to model a supposedly simple scenario, using option 1. I am a novice with this program – so please bear with me. When I run my model, the dam does not breach because it never reaches the trigger elevation for the start of the dam failure to commence. (The inflow hydrograph is steady-state, witch minimal base flow the program allows. The first thing I tried, to breach the dam, was to increase the inflow. However – I have to increase it significantly to a point where it does not reflect any realistic conditions. My other main concern is that I have to rerun the model (after the kinks are out) with the reservoir elevation lowered by 20 feet (With this initial condition, I will never fill up the reservoir up to that trigger elevation).

Can I play with the “elevation of water when failure of dam commences” parameter? Is there a limit to how low I can set it to? Do I have other options?

[Chris Maeder]

Note that you can set the "trigger elevation" for the dam failure to any value you want. As long as the reservoir water surface reaches it, the dam will fail.

Sincerely,

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

[emilias]

I am trying to model a single reach with a single dam using option 1. I took out all elements (boundary conditions) that made the model more complicated. I did get a hydrograph with a smaller inflow (but also without a dam break). However, when I increased the inflow I get convergence errors. Specifically, I get negative values for the stage (at the hydrograph) and a message that my top widths need to be extended (which is questionable because I have at least 120 feet of top width height and I am not expecting such a high stage). I have also decrease the dmx, but I get the same errors. Do you have any suggestions?

Also (attached is my input file).

Thank you for any pointers you could provide.

[Chris Maeder]

You will need to contact me directly in order for me to troubleshoot your DAMBRK model. Also, in your email to me, explain in detail what it is you are attempting to accomplish and what you have run into as far as problems.

Sincerely,

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