Error messages

Chris

I need your help. I have attached the .dbk file and .g01, .g02, .g03, and .g04 files into gary.zip (name of file:03)

I am getting 2 error messages and they are:

1) Inflow hydrograph contains low inflow values, these values may cause analysis difficulties

2) Inflow hydrograph safety-net featurs will be activated during analysis, since theta weight factor has not been set to 0.5 in the boundary conditions.

What I have done:

1)I have tried increasing my baseline flow in the inflow hydrgraph description and continue to receive error messages. I believe this will work if the Upstream Reservoir Description for the surface area was increased (see below).

2)In Upstream Reservoir Description I have increased to the highest contour for the surface area. I believe it is not getting enough water behind the dam to run the analysis. Do I need to add fictional values in this field and not put the true lake size to get enough volume of water for a breach?

I am able to run the analysis with the examples we had done in class so I know it works. In fact, I used one of the examples and modified it with the data of this present dam and now it does not run.

Thank-you for your time and consideration,

Gary Wells, P.E.
Water Resource Branch
Dam Safety and Floodplain Compliance

Dear Gary :

Nice to hear from you. I really enjoyed the time in Frankfort, KY teaching. You are very lucky to have such beautiful surroundings.

These messages that you are reporting are really not error messages, but warning messages. They are meant to be informative to the modeler, and do not necessarily mean that there are problems with the model. However, should the DAMBRK model not run, then these are possible locations where you might look to solve the problem.

The warning message "Inflow hydrograph contains low inflow values..." is always generated when there is any value defined in the inflow hydrograph that is less than 1000 cfs (or equivalent value for cms). However, again, this does not mean that DAMBRK will not run. However, DAMBRK is a "wet model" and needs to have a certain amount of base flow to start up and run. A flow value of 0.0 will definitely cause DAMBRK to fail. And, if your flow value is low and the channel bottom wide and flat (so that essentially there is minimal flow depth), then again DAMBRK will most likely fail to run.

The warning message "Inflow hydrograph safety-net feature..." is generated whenever the Theta Weighting Factor has not been set to 0.5. Setting the inflow hydrograph safety-net feature is something that Dr. Fread added to the DAMBRK program to prevent the river base flow from dropping less than the initial flow value at time 0.0 that was defined in the upstream most reservoir inflow hydrograph.

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