The petition shall: clearly describe the area’s location, boundaries, and need of drainage for optimal crop production; describe how draining or ditching the area or changing the natural watercourse benefits the public or promotes the public health, safety, or welfare; and request the establishment of a drainage association for the purposes listed in item (2) of this subsection. A petition is valid only if signed by at least one–third of the landowners or the owners of at least one–third of the land in a watershed.