Weir equation used by HEC-RAS seem not to consider the effect of the flow velocity upstream of the weir.
In mountain rivers the flow comes with rather high kinetic energy and the results are very different.
Is it possible to perform a calculation considering the upstream speeds with HEC-RAS?
Alberto
No I don’t think the weir equation takes into account the upstream velocity. A simple solution would be to increase the value of the weir coefficient to allow more flow.
If the velocity varies over the course of the run, you could use the advanced rules to get the upstream velocity and change the weir coefficient during the run. Or use the advanced rules to adjust the flow in some other manner.
Thanks jarvus.
I wanted to make sure there was not a more correct way to calculate a weir.
It could be a good idea to impose a rating curve, previously calculated.