One thing I learned is that the HEC-RAS procedure used is based on a broad crested weir which is not affected as much by submergence as a sharp crested weir.
I said "developed by Brater & King," but that's not really the case. Brater and King published work done in '47 by Villemonte. Possibly the method used in HEC-RAS is based on something more recent?
What is the best method to compute Q over a submerged weir?
My discharge is 344 cfs, weir length = 40'. Tailwater is 1.4' above the weir (H2). Assume a sharp crested weir.
The procedure in HEC-RAS results in no reduction, so H1 = 2.0'
The equation developed by Brater & King, '76 results in...
Modeling a system in very flat topography that. Channel has a wide flood plane once it jumps out of its ~2yr channel. We have set up a HEC-RAS and it is interesting to notice that the HW on culverts are higher using HEC-RAS than HY-8. 1.7' higher for a Q of 387 cfs.
Assuming one has...
