Patent ID: 6779946
Filing Date: 2004-08-24
Classification: A01G,E01C,E01F,E02B,E03F,Y02A

Abstract:
A drainage structure which is generally flat in nature and is for use mainly in a horizontal or substantially horizontal disposition, and comprises top and bottom plate members which are held apart by spacer members so that the structure is cellular in nature with the cells hydraulically interconnected with each other, the plate members having apertures therein which are disposed so that the apertures in the top plate member are offset relative to the apertures in the bottom plate member, and wherein there are web walls extending between adjacent spacer members at the lower plate member, the web walls forming weirs at their top edges, for water retained by the web walls, wherein the top edges of the web wall are curved, to cause the water spilling over these edges into adjacent cells at a varying velocity profile to increase the oxygenation of the water as it splashes on falling from the weir top edges.