Every watercourse any section or reach of which runs through or constitutes a boundary of any drainage district shall, within the meaning and intent of this act, be deemed to be within such district for the distance that it runs through or constitutes such boundary thereof; and whenever any watercourse constitutes a boundary of any district, such district shall have jurisdiction and control over the whole width of such watercourse between the banks of highwater mark for the distance that such watercourse constitutes such boundary, except that in cases where drainage districts shall be organized on opposite sides of and bounded by the same watercourse or the watercourse is the boundary of the state of Kansas, the jurisdiction and control of such districts shall respectively extend from the bank on the side of such watercourse on which the district is located to the center of the main channel thereof. When a drainage district has been incorporated under the provisions of this act after the whole or any portion of the channel of any watercourse, title to which is vested in the state of Kansas, which watercourse constitutes a boundary of any such drainage district, shall be abandoned, or no longer used for a channel, the secretary of state shall cause the same to be surveyed and sold in accordance with the provisions of Kan. Stat. Ann. §§ 82a-209 to 82a-211, inclusive, and the purchasers of said land so sold shall take fee title subject only to the drainage district’s rights to exclusive control and possession for its corporate purposes including impoundment rights, flowage easements and other interests of the drainage district essential to its plan of flood protection or reclamation, and said purchasers shall have the full enjoyment of said lands subject only to the aforementioned rights of the drainage district.