I have a relatively simple, but large model and I'm carring out an Manning's sensitivity analysis. I'm looking into the stability of a channel, so I am comparing stream power, bed shear and velocity results. I have carried out two runs using the same files for everything except the materials mapping file and the materials.tmf file.
The results have shown that the stream power and bed shear both increase with increased Manning's roughness. This seems totally incorrect because the velocities should reduce, bringing the other measurement down with it. Incidentally, the velocity does appear to reduce.
I've taken my results along the channel centreline using the dat_to_gis tool to find peak values, followed by the extraction of results along the mapped centreline.
I am wondering whether the peak values have come from a different time to the peak flow, or perhaps stability issues have caused a spike in the results. I don't think stability is the issue because the model seems happy and there are a large number of results along the channel length and I doubt spike would occur everywhere. I guess my questions are; when are peak values of power and shear collected and has anyone else had issues with these values increasing with increased roughness?