Wall element and assembly for holding back water

A wall element for use in an assembly for holding back water, wherein the wall element is formed in one piece and has a planar, rectangular main portion having a first side, a second side parallel to the first side, a third side perpendicular to the first side, and a fourth side parallel to the third side, and the wall element has a first planar bearing portion that is connected to the main portion along the length of the first side and extends perpendicular to the plane of the main portion, and a second planar bearing portion that is connected to the main portion along the length of the second side and extends perpendicular to the plane of the main portion, wherein the second bearing portion extends in a direction opposite to a direction of the first bearing portion relative to the plane of the main portion, and the wall element has a first connecting portion that is connected to the main portion along the length of the third side and angled relative to the plane of the main portion, and the connecting portion has a plurality of connecting holes in a longitudinal direction of the connecting portion and passing through the connecting portion, and the main portion has a plurality of connecting holes which correspond to the plurality of connecting holes of the connecting portion and are arranged along the fourth side, wherein a first surface of the first and second bearing portions directed toward the main portion is a contact surface for a plurality of fasteners connecting the wall element to a ground surface, and a second surface of the first and second bearing portions directed away from the main portion is a bearing surface for a seal between the respective bearing surface and the ground surface.