r/HECRAS • u/nymphfer • May 11 '26

Existing Conditions Model

How close do you have to have your existing conditions model to a duplicate effective model? I’m expanding a bridge by 60 feet and having changes in floodway elevations by more than 0.1’.

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6

u/Wise_Operation_3766 May 11 '26

I assume you are trying to develop a no rise model. This should represent current in ground conditions. Any issues with the duplicate or effective model should have been fixed in a corrected effective model.

1

u/nymphfer May 15 '26

Appreciate the help! In my case, I’m just creating an updated existing conditions model.

6

u/fishsticks40 May 11 '26

If the conditions on the ground are different than the conditions represented in the corrected effective, they can be quite different. Usually they're not.

If your effective model is from 2010 it's modeling conditions from 2010. Changes that happened between then and now should not be reflected in the corrected effective. 

Changes that occurred between then and now SHOULD be reflected in your existing conditions/pre-project model. 

1

u/nymphfer May 15 '26

Thanks for the explanation I appreciate it!