We recently began experimenting with SSA and are trying to verify the inlet calculations that were done in excel to make sure we understand the software before putting it into everyday use. We've created a custom parabolic street section and applied it to the bypass links, and as far as that aspect goes, we understand it and it's all working great.
Our issues come in figuring out how to model inlets directly across from each other in a street section. The issues arise when the top width (of Inlet 1, in the attached graphic, for example) exceeds the half section width and flows over the crown into the opposite side of the street (to Inlet 2, in attached graphic).
Any suggestions? We have tried weirs and flow diversions to no avail. Attached is an example of what I'm trying to explain. Inlets 1 and 2 are opposite from each other, and both connect into a MH labeled SD-J 29+33.00. Link-05 connects to the next downstream MH, and there are 2 links that follow the gutter lines to the North used as bypass links from Inlets 1 & 2.
Unfortunately, only a single surface outlet from an inlet is allowed. There would be no implied connectivity between the inlets.
From your description, Inlet-1's depth is large enought to that the spread exceeds 1/2 of the street width. I would likely swap the inlet for two junctions, one that models the surface connection together with a lower manhole junction. Between the surface junction and the manhole, I would add an orifice with the dimensions of the inlet structure, and then model the surface connections between the downstream structure and Inlet-2.
Thanks for your prompt reply. That was the answer I was expecting but not hoping to receive. I'll see if I can make it work, but I'd like the two inlets to be able to "interact" to know which would be overflowing the crown instead of having to know that from the outset.
The only problem with an orifice as suggested is that it doesn't account for dynamic trajectory flow parameters that a rating curve built from proprietary inlet calculations would provide if these inlets are on-grade.
I would use two storage nodes connected with a weir to model flows back and forth across the crown, and inlet rating curves implemented in Outlet connections with flap gates closed connected to the lower nodes for the pipes, and orifices between the lower nodes and inlet storage nodes to model the possible flow reversals.
Access a broad range of knowledge to help get the most out of your products and services.