Modeling houses in floodplain
Modeling houses in floodplain
(OP)
I have a channel running through a residential subdivision. Just wondering how you model houses in the overbanks.
I've seen two separate ways. One is using a little higher n value of 0.07 in the overbanks and using ineffective flow areas (for the storage, but essentially no conveyance). The other way bumps up the overbank n to 0.10, but with no ineffective areas. Your thoughts?
I've seen two separate ways. One is using a little higher n value of 0.07 in the overbanks and using ineffective flow areas (for the storage, but essentially no conveyance). The other way bumps up the overbank n to 0.10, but with no ineffective areas. Your thoughts?





RE: Modeling houses in floodplain
RE: Modeling houses in floodplain
It would either require me to have cross-sections every 40-50', which would be overkill. Or it would have blocked obstruction throughout the entire overbank, which would eliminate any sort of storage.
RE: Modeling houses in floodplain
RE: Modeling houses in floodplain
RE: Modeling houses in floodplain
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Modeling houses in floodplain
Recently, the City recently went in and upsized some box culverts which were shown by the previous RAS model to be causing a restriction in the channel. This consultant (different from the previous one) took the previous model, and inserted the revised culverts into that model. However, they also removed a lot of the previous ineffective flow areas for the housing areas.
I'm now working on the LOMR for that last piece. I want to keep the model as close to the one that was used to get the original LOMR, which used n=.07 with ineffective for the overbanks in housing areas. But in a model I received from FEMA for a completely separate project, they used an n=.10 with no ineffective areas. Which is what prompted the original question.
RE: Modeling houses in floodplain
Let us know how yours goes.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com