HY-8 and Multiple Culverts

[saruman26]

I am getting an odd error in HY-8 when analyzing multiple culverts.

My situation is this - a new road crossing, with two arch RCP pipes. The first is a 62x102 with the invert buried into the stream bed 12". The second pipe is a 54x88 with the invert at the stream bed elevation. When running the analysis, I get two different headwater elevations, and most of the flow is routed through the smaller culvert, and the roadway overtops.

When I check the design flow for a similar condition in Hydraflow Express, I get adequate freeboard and no overtopping. Any ideas? I have attached the file in question.

 

[saruman26]

Update on this post. I created a new HY-8 file and entered the data anew. This time, I get the same W.S.E. for both culverts. Now it appears to work.

I stumbled upon a similar post here from 10/2008 where the user had the same problem. Perhaps an odd glitch in the coding?

Thanks in advance to anybody who might have responded.

 

[francesca]

Are you using the latest version? The previous version of HY8 definitely had a few glitches.