Lateral Flow Into Stream

[huesmann]

Suppose you’re modeling a stream with cross sections and a culvert. You have a cross section upstream of the culvert, but you also have a storm drain that dumps into the stream just upstream of the culvert, but downstream of your cross section. Say the flow in the channel at the cross section is 50 cfs, but the flow at the culvert (due to the add’l flow from the storm drain) is 75 cfs. How do you model the flow so that you’re modeling 50 cfs at the cross section and 75 cfs through the culvert?

[Marulke]

Cant you add an extra cross section upstream the culvert, and set a flow change at that cross section? Or add 25 cfs as lateral inflow between two CS just before the culvert inlet.

Just an idea.

Marulke

[huesmann]

The problem is that the culvert is basically at the confluence of two streams–the major one I’m modeling, and a minor one that adds a little flow.

How does one add lateral inflow? I’ve only done lateral outflows.

[Marulke]

I don’t really understand the problem.

If the flow is subcritical, the water level is controlled from downstream. So, if you have the correct down stream water level (boundary condition) and the correct flow on the reach from the DS BC and up to where the tributary enters, you should get the correct water level at that CS.

Are you concerned about the detailed flow pattern and water levels just where the tributary enters?

Marulke

[Author]

Posts