FEMA and non-flood walls

[damueller]

I have a project where the owner wants us to prepare a LOMR based on an existing wall adjacent to a flood control channel. Part of the wall is a concrete masonry wall and part is a concrete panel wall. Therefore, I'm fairly sure this isn't a floodwall per FEMA Standards or COE regulations.

I worked on a previous project for a remapping study where FEMA said we could consider the bottom 1' of a concrete masonry wall as an obstruction in HEC-RAS. So, essentially we were able to use the bottom foot as part of the adjacent channel.

Does anyone know if I can consider a part of this wall as an obstruction? Or, would we totally discount the wall?
Thanks in advance.

 

[cvg]

evaluate the wall. If it is designed to handle flood loading and scour, then it might be considered a floodwall. This would have to be approved by FEMA. If not, then either an obstruction or assume it fails and washes away. By the way, a lot of FEMA approved floodwalls are constructed of masonry.