HEC-RAS Overtopping Problems
HEC-RAS Overtopping Problems
(OP)
Hi All,
I am currently running into a problem with HEC-RAS. I currently and modeling a bridge where the immediate upstream cross section is approximately 26-ft away. When I run the model, the water surface elevation at the immediate upstream x-sec is 2-3ft above the bridge x-sec. The model currently has all the flow being conveyed through the structure. I know this is not physically possible.
I am using the standard step method for both high and low flows.
I used the momentum equation but that did not work.
I also used the pressure/weir flow module too. But that did not work either.
Any tips?
I am currently running into a problem with HEC-RAS. I currently and modeling a bridge where the immediate upstream cross section is approximately 26-ft away. When I run the model, the water surface elevation at the immediate upstream x-sec is 2-3ft above the bridge x-sec. The model currently has all the flow being conveyed through the structure. I know this is not physically possible.
I am using the standard step method for both high and low flows.
I used the momentum equation but that did not work.
I also used the pressure/weir flow module too. But that did not work either.
Any tips?





RE: HEC-RAS Overtopping Problems
If I saw this behavior, and I didn't expect it, I would probably start by checking the culvert slopes and inlet loss coefficients for data entry error. HEC-RAS is quirky and there could be any number of things going on, but those two are the first I'd check based on the actual science, to see if my model was actually giving me a correct answer for the wrong input.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com