18 CFR §415.31

1. (a)Within the floodway, except as permitted by special permit, the following uses are prohibited:
   1. (1)Erection of any structure for occupancy at any time by humans or animals.
   2. (2)Placing, or depositing, or dumping any spoil, fill or solid waste.
   3. (3)Stockpiling or disposal of pesticides, domestic or industrial waste, radioactive materials, petroleum products or hazardous material which, if flooded, would pollute the waters of the basin.
   4. (4)The storage of equipment or of buoyant materials, except for purposes of public safety.
2. (b)Within the flood fringe, except as permitted by special permit, the following uses are prohibited:
   1. (1)Stockpiling or disposal of pesticides, domestic or industrial waste, radioactive materials, petroleum products or hazardous material which, if flooded, would pollute the waters of the basin.
   2. (2)Any use which will adversely affect the capacity of channels or floodways of any tributary to the main stream, drainage ditch, or any other drainage facility.