HEC-RAS Inline or Lateral Weir?

[mobius42]

I haven't modeled much outside of a few nice channel relocation/stabilization projects and am now running into a development project that is a bit difficult to visualize from a modeling approach. I have attached a PDF of the area in question.

The channel in this area has been filled in over time and is now a large shallow floodplain that weirs over the top of two highways and dumps into a recently built channel. The channel is part of a master drainage plan that extends through the site being developed. Looking back at the models at the time of the residential development and the redevelopment of the highway intersection, both models ignore pipes and box culverts under the highway.

We started out looking at adding the pipes under the E/W highway to allow for more development, but now are being directed to look at adding pipes under the N/S highway. However, It doesn't feel like this is possible to model while still meeting the 4 cross section requirements for culverts/bridges and not overlapping cross sections due to the way the existing channel runs. I started reading through inline and lateral weirs, but again it feels like I can't make the cross sections work. Any tips would be welcome.

 

[gbam]

mobius - you are not limited to the 4-xsecs. if you use your ineffective boundaries on more of your xsecs you will account for the contraction and or expansion. I commonly use more xsecs within the "standard" lengths between the "4" xsecs. I use ineffective boundaries based on expansion and/or contraction ratios. Basically don't feel tied down by the "4".

 

[mobius42]

That makes sense. Thanks for the reply.