Outlet drainage districts may be organized in the manner provided in Sections 3-3 through 3-26:
(a) When an open drain, whether natural or artificial, or partly natural and partly artificial, constitutes the common outlet for lands in two or more other drainage districts which may or may not adjoin or for lands in two or more such other drainage districts and lands not within any drainage district; and(b) When the purpose of the outlet district is to improve the channel of the open drain constituting such outlet; and(c) When the lands to be included in the outlet district are contiguous and will be benefited by the work of the outlet district; and(d) When all or a portion of the lands to be included in the outlet district are situated in two or more other districts. Any lands which will be benefited by the work of an outlet district may be included therein without regard to whether such lands do or do not lie within another district, however, it shall not be necessary to include in an outlet district all lands which will be benefited by the work of the outlet district or all lands lying within the other districts draining into the outlet proposed to be improved.