In every county in this state in which there is now a drainage district and in which a drainage district may hereafter be created or be proposed to be created under this chapter, the board of supervisors of such county shall select three county drainage commissioners for such county. The term of office of each commissioner shall be six years and until his successor is selected and has qualified, with said terms expiring at two-year intervals to insure the selection of one new commissioner every two years. Any vacancy in office of a county drainage commissioner in any county may be filled by the board of supervisors at any regular meeting of such board, which board is given the authority to fill all unexpired terms of any commissioner in the county.

Every resident citizen of any county, being the owner of land in said county and over 25 years of age, of good reputation, and of sound mind and judgment shall be eligible to hold the office of county drainage commissioner in the county of his residence.

If any commissioner shall refuse or neglect to discharge the duties imposed upon him by virtue of this chapter, or shall neglect or refuse to qualify as such commissioner after being selected for such office, the other two commissioners shall proceed to exercise the duties of their office and the business of said drainage district until the next meeting of said board of supervisors, when the office of the party refusing to perform or qualify shall be filled by the selection of another party in his stead.