Patent ID: 7108454

Claim:
A drain structure panel for a subsurface drainage assembly, comprising: a laterally extensive backing grid having a plurality of struts defining grid openings therebetween and a plurality of side edges; a plurality of spaced apart support members projecting from the backing grid, the support members having an upper end, a lower end, and a sidewall extending therebetween, each of the support members having at least one opening formed through the sidewall so as to intersect the lower end of the support members whereby fluid may flow from the support members via the opening when the lower end of the support member is engaged with a surface, the opening includes two corners extending from the lower end of the support member, wherein each of the corners is rounded; and complementary sets of male and female fasteners formed on the side edges for connecting the drain structure panel to a laterally adjacent drain structure panel, the male fasteners being received in and slidingly locked to the female fasteners of the adjacent drain structure panel, wherein the male and female fasteners substantially permit expansion and contraction of the drain structure panel and the adjacent drain structure panel relative to one another in a lateral direction.