HEC HMS ERROR:Initial Elevation

[scottt621]

I am working on designing an outlet control structure for a large detention pond with a tailwater condition. I have gotten the model to run with just using orifice outlets. I want to use a spillway at the top of the structure but whenever I add a spillway into the model, I get the following error:

ERROR: Error in computing initial elevation for Detention Pond;
Independent variable, 0.0, has two dependent values: 37.122201600000004 and 37.162435200000004
Function: InterpolateLinear; Error number: 13

I have been playing with this a bunch and the only way to get the spillway to run is to set it below the tailwater elevation level. I have beaten myself up over trying to figure out where i am going wrong on this. Any ideas will be helpful. Thanks.

 

[SMIAH]

Check both your discharge-elevation or volume/area-elevation relations to ensure that you've specified the same elevation/data for each of them.

 

[gbam]

Have you tried creating a combined rating curve for the combo outlet and spillway? This is a hold over from HES-1, but it always worked for me.

 

[beej67]

I've gotten that error on HEC-1 imports to HMS before, and fixed it by doing what SMIAH said.

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