Flood Zone Estimation

I was working a recent job where the land owner needed to estimate how much of his land had been lifted out of the flood zone after adding quite a bit of fill to his site. Obviously since the work had just been done, the FEMA and GIS sites did not have an accurate map. This was creating some angst with his bank. He could have spent thousands of dollars to have a surveyor come in, but that was really beyond the scope of what he needed.
With drone imaging, we were able to provide an estimate of the impact. The land was previously about 50% in the flood plain. Our mapping showed that it is now only 20% in the flood plain. The attached images show the standard aerial map on the top and the topographic relief on the bottom.