Hydraflow Express for 2021 does not calculate Channel Flows correctly in TR-55

[AdammReilly]

I found this while working on a new project: I created a Hydrographs file and then created an Express file to size a culvert.

The hydrograph matches all the same data for both programs, but the Express version is not calculating the time of concentration properly for the Channel Flow segments.

See the image below:

(H is the hydrographs file, E is the Express file)

I have the same data in a spreadsheet I've been using for years and it gives me the same figures as Hydrographs. I thought maybe Express wasn't converting the Tc to minutes, but 2.6 minutes is 0.0433 hours, so I do not think that is it.

I've reported this, but just thought I'd let everyone know about this issue.

[Nilesh_Chaudhari]

Hi @AdammReilly ,

Thank you for posting this. Do you have a case number or defect ID? 

[AdammReilly]

Case number is 16830081

[fcernst · Accepted solution]

It looks like the flow length in Express is only 3.77 feet..

[AdammReilly]

I finally found that after most of a day grumbling about it lol. And I only noticed it because I started another model that calculated correctly.

I need a vacation 😫