A hearing by the commission on proposed changes as provided by section 2-3207 may be initiated by any of the following methods:
(1) By the commission on its own motion;
(2) By written request of a majority of the directors of any or each natural resources district the boundaries of which are proposed to be changed or which is proposed to be merged or divided;
(3) By petition, signed by twenty-five percent of the legal voters residing within an area proposed to be transferred from one district to an adjoining district by a change in boundaries; or
(4) By formal written request of a majority of the directors or supervisors of any other special-purpose district wishing to merge with a natural resources district.
Such proposals shall be filed with the department and shall set forth any proposed new boundaries and such other information as the commission requires.