Written by Christopher Goodell, P.E., D.WRE | WEST Consultants
Copyright © The RAS Solution 2016. All rights reserved.
***Update: I received a few very important comments about this post that I want to share.
First, and this is very important: These methods are not meant to be used to do any kind of detailed bridge design or bridge scour analysis (contraction, abutment, or pier scour). The methods I present in this post are strictly as a means to include a bridge in a 2D area to gage its effect on the overall resulting flood inundation. Meeting FHWA standards for bridge modeling requires much more information than these options will provide you.
Second, Mark Forest posted a couple of very good comments that I would like to share. Please read his comments at the end of this post.
There have been a lot of requests for examples of how to model bridges in 2D areas. First, let me state up front that in the current version (5.0.1) there is no direct way to put a bridge in a 2D area, like you would in a 1D reach. That means, that we currently don’t have a way to use low flow bridge modeling approaches like Energy, Momentum, Yarnell, and WSPRO. Likewise, you can’t use the high flow approaches (Energy, Pressure/Weir). Hopefully this will be added to a future version.
That being said, I’ll present three options for simulating bridges in 2D areas.
To demonstrate these options, I used a dam breach model adapted from HEC’s Bald Eagle Creek data set. The animation is included at the end of this article.
