(1) The maintenance of adequate drainage within the confines of certain counties of the state is hereby declared to be a matter of public health, convenience and welfare.
(2) The use of road ditches, the use of public and private ditches and natural watercourses for drainage requires some coordinated system of control and maintenance.
(3) Where portions of the drainage system of any county are not included within the boundaries of any drainage district organized under Chapter 31, article 3 or 4, or within the boundaries of any sanitary drainage district organized under Chapter 31, article 5 or 7, the county board may assist in the control and maintenance of the drainage of any area within said county, under the provisions of sections 31-901 to 31-933.