Whenever the board of directors of any levee district shall, by petition, show to the county commission or other legislative body of the county in which said levee district is situated that there are lands in said county which are subject to overflow, and inundation from the same rivers, crevasses, or bayous as other lands included in said district, and which said lands are not included in said levee district, and asking that said lands be incorporated in said district, the county commission or other legislative body shall cause notice to be given to such landowners requiring them to appear at the next regular meeting of said commission or other legislative body and show cause why such lands should not be incorporated into said levee district, and at the next regular meeting the commission or other legislative body shall proceed to hear and determine the matter; and if it shall appear that such lands are subject to overflow and inundation from the same rivers, bayous and crevasses as the lands in said district, the commission or other legislative body shall make an order incorporating such lands into said levee district, and the assessor shall assess the benefits to said lands to be derived from the building of levees constructed or to be constructed by said levee district, in the same manner, and the board of equalization shall act upon the same in the same manner as heretofore provided in sections 245.285 to 245.545; provided, that if the owner of any such lands be a nonresident of the county, he may be notified by registered mail to the address used by the county assessor for tax purposes.