Mo. Rev. Stat. § 644.018
In any contested case or judicial proceeding filed after January 1, 1998, involving surface water in any flood-prone area, if any defendant has obtained and fully complied with a permit from a political subdivision which has enacted orders or ordinances as required by the Federal Emergency Management Agency as a prerequisite to participation in the National Flood Insurance Program, and which political subdivision has jurisdiction, pursuant to the zoning laws of this state or the laws and regulations of the Federal Emergency Management Agency, over the area in dispute, then the proper permitting and compliance with all conditions of such permitting of such project shall be conclusive proof that the project is a reasonable use and meets any reasonable-use test imposed by law or by a court.
§ 644.018, RSMo
Effective 6/9/1998