Drainage districts may hereafter be organized in this state under the provisions of this chapter for the purpose of reclaiming wet, swamp, or overflowed lands for agricultural and sanitary purposes conducive to public health in the manner hereinafter provided and, when so organized, shall consist of a system of artificial main drains, lateral drains or ditches, natural drains and water courses, or levees. To the end that the purposes of the organization of such districts according to this system may be attained, they shall have and are given full power and authority to construct or to cause to be constructed such artificial main drains and ditches, lateral drains and ditches, and tile drains over the lands of others or over or on lands which may be acquired by said district, and to alter, deepen, or improve any and all natural drains and water courses as it may be necessary to alter, deepen, or improve so that a complete system of such drains may exist in the district for agricultural and sanitary purposes. Such districts may also, in addition to the construction of such drains, construct or erect over the land of others, or over the lands to be acquired by the drainage district or commission for that purpose, such levees as may be necessary to protect or reclaim any lands from overflow from any source.