Samantha West

Bill, I have tried changing the "apply all Inverts" back to pre 2006 defaults however I still get the same problem. I deleted the weir that was seemingly causing the problem however this just changed the location where the hydrograph suddenly drops away. The problem is now occuring at a 1d/2d interface. The 1 and 3 hour event runs fine as the peak flow is only 80m3/s. However once the flow reaches 100m3/s the hydrograph drops to 0. This doesn't occur at any other location of the model. The output hydrograph has NaN where the error occurs. It seems like it is going unstable but continues to run anyway. The main difference is I have a lateral channel section coming in. The two incoming channels go from 1d to 2d and then back to 1d for the downstream channel. I have attached a diagram illustrating this. The diagram also shows no flow in the 1d channel (probably to do with the NaN) however it is still spilling out into the 2d. Do you have any ideas of what is causing this? Model_diagram.pdf

I am running an old 2004 1D/2D model which runs fine. I am now attempting to run this model in the 2008 version of Tuflow. I have found that in one section of my 1D channel the output hydrograph shows some instabilities. The hydrograph within the next section of channel reaches the peak flow and then drops to zero. This is then carried through the rest of the channel. I'm wondering what would cause the model to lose half the volume of water. I can't see anything unique about that particular section of channel. I did have a culvert there which I thought was the cause but when I deleted I still got the same problem. Any help would be appreciated. Cheers

Hi Bill, Thanks for the advice. I now have realistic results. Cheers