footing depths in riverine flood zones

[struct_eeyore]

Hi all,

Currently working on a building situated ~100' from a river edge. Single story, commercial, cmu walls (on hopefully spread footers). My concern is that should any flooding occur, there might be washout that will undermine the footings; however, I cannot find any info either in the building code or FEMA about required footing depths. Is this something that is usually taken into consideration, and are the obligating requirements for footing design in this situation? Who would be the professional to contact in such a case?

Thanks in advance

 

[cvg]

you need a hydraulic / drainage engineer to estimate the flood water elevation, scour depth, erosion and design the site / structure to prevent damage. You may also need to consider high groundwater levels. you may also need to get a floodplain use permit to build in a flood hazard zone

 

[oldestguy]

If you can't follow cfg's recommendation, consider the depth of scour to be at least the height of flood above the ground there. Also use building code for usual footing depth as a minimum.

 

[azcats]

Have you determined your flood zone, base flood elevation and site elevation?

 

[struct_eeyore]

yes, base flood and site elevation are available. current site is 14 and is being brought up to 15.5 which is the base flood. We are hoping to have continuous mono footers all around, so it'l likely not a scour issue but and proper erosion. We will be getting a hold of a hydraulic/drainage engineer - was just looking to confirm that we should not anticipate piles.