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CJ 48
August 9, 2016, 08:04 AM
Stormwater InfoSWMM: What is the best method of 4 - 54" circular pipes at a single road crossing? Not sure it I should use a single equivalent size pipe or can I add 4 conduit to each sides junction? Thanks

Robert Dickinson
August 9, 2016, 07:37 PM
Stormwater InfoSWMM: What is the best method of 4 - 54" circular pipes at a single road crossing? Not sure it I should use a single equivalent size pipe or can I add 4 conduit to each sides junction? Thanks


Hello CJ,
You can model these a variety of ways:
1. If each pipe has the same upstream and downstream invert then you can model one link with 4 barrels
2. If you want to have all 4 pipes with different inverts or geometry/losses then model all 4 links - you do not need an equivalent pipe
3. Each of the pipes can be modeled with a FHWA culvert type using the culvert code
4. The road over-topping can be modeled as a weir

Best Regards,
Robert Dickinson