HEC-RAS or HY-8 for Culverts?
HEC-RAS or HY-8 for Culverts?
(OP)
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 accuratly inputted the data appropriately for each model, is one consider more accurate than the other? Curising the web I found one comment that indicated that HEC-RAS is considered to be more accurate than HY-8.
Assuming one has accuratly inputted the data appropriately for each model, is one consider more accurate than the other? Curising the web I found one comment that indicated that HEC-RAS is considered to be more accurate than HY-8.





RE: HEC-RAS or HY-8 for Culverts?
1. How do the tailwater elevations compare?
2. If the roadway overtops, how does the weir-flow quantity compare?
3. Are you using ineffective flow areas in HEC-RAS to account for transition near the culvert?
4. How do the culvert losses compare?
I haven't used HY-8 much, but I would say that if you have accurate channel data downstream and upstream of the culvert, HEC-RAS may be a better modeling approach (unless the culvert has a bend or varying slope).
RE: HEC-RAS or HY-8 for Culverts?
Does it overtop? If so, check to see that the length of overtopping in both models is the same.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: HEC-RAS or HY-8 for Culverts?
RE: HEC-RAS or HY-8 for Culverts?