Mo. Rev. Stat. § 236.180: Privilege to erect subject to certain conditions.

The judgment and order authorized by sections 236.160 and 236.170, and the rights and privileges thereby granted, shall, in all cases, be upon and subject to the conditions following:

(1) Such conditions in reference to the obstructions to the passage of fish and ordinary navigation, as the court shall think proper to impose;

(2) That all damages and valuations assessed and made by the jury shall be paid;

(3) That the dam and mills, electric power and light works, or other machinery, shall be commenced within one year, and finished and ready for business within three years from the date of the order of permission;

(4) That whenever the dam or mill, electric power and light works, or other machinery, shall be destroyed or materially impaired, the same shall be built or repaired within three years thereafter; but if the owner of such dam or mill, electric power and light works, or other machinery, shall be an infant, or of unsound mind, or imprisoned at the time such dam or mill, electric power and light works, or other machinery, shall be destroyed or materially impaired, then within three years after such disability is removed.