I did something similar, built a house in a 100 year floodplain and used the pond spoils to raise my house and barn. I had to hire a surveyor to make sure I was above the flood plain, and that same surveyor sent the paperwork to FEMA so I could get a LOMA and get out of paying flood insurance.
In addition to whatever your surveyor charges, FEMA charges $425 for "processing the paperwork" and gets back to you within a month or so. Also you have to have someone in your local government sign a form stating they are aware and approve of the changes you have made.
Other than the bull&^%# $425 fee (I thought thats what taxes are for) it wasnt too bad
