Missouri Revised Statutes Title XV. Lands, Levees, Drainage, Sewers and Public Water Supply § 243.020. County commission authorized to organize drainage districts

1. When it shall be conducive to the public health, convenience or public welfare, or when it will be of public utility or benefit, the county commission of any county in this state shall have the authority to organize, incorporate and establish drainage districts and to cause to be constructed, straightened, widened, altered or deepened, any ditch, drain, natural stream (not navigable), bank protection, current control, or watercourse, when the same is necessary to drain or protect any land or other property.

2. The petition for any such improvement shall be held to include any side, lateral, spur, or branch ditch, drain, watercourse, or levee, the lowering of any lake, the protection of the banks of an adjacent stream from wash, cutting or erosion or any other work necessary to secure fully the object of the improvement, petitioned for, whether the same is mentioned in such petition or not. The commission may establish any such side, lateral, spur or branch ditch when the main ditch is established, or at any time thereafter, and the commission shall require that proper compensation be given the main ditch district for the outlet afforded such lateral, side, spur or branch ditch; provided, that in the event any work is to be done upon any navigable stream, the consent of the federal government shall be obtained to make such improvement or improvements before the actual work on the improvement shall be begun.