Higher WS Elevation Upstream of Bridge with Fewer Piers

[Anonymous]

All things set equal between two geometries: the only change was going from a 2-pier (equally spaced spans) to a 1-pier (again equally spaced spans) bridge. Pier geometry is set equal. The 1-pier configuration gives a WS and Energy Gradeline that is above the 2-pier configuration (approximately 3 feet higher). This is counter-intuitive. Immediately downstream of the bridge, the WS and the Energy Gradelines converge.

Changing settings under the Bridge Modeling Approach Editor had no effect on the results.
Changing the Flow Regime had no effect on the results (it is running subcritical).

Any suggestions on what is causing this unexpected result?

[Anonymous]

What is the Diam of the piers?

[cameron]

What bridge method is used for both geometries, does it change from one to another when solving?

[Author]

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