Patent ID: 6872032

Claim:
A drainage system comprising: a wall structure comprising joined-together blocks forming a composite outside surface, each block having a set of liquid-impervious walls defining a completely bounded first cavity and a completely separate and bounded second cavity, the first cavity having a sealable fill opening for introducing a fill material to add weight, and the second cavity of individual blocks having a first opening for matching with first openings of adjacent blocks for passing liquid between blocks, and a plurality of second openings through the composite outside surface; and a drain grid comprising a planar mesh material having a width W and a length L, and a plurality of spaced-apart and parallel conduits for liquid, each conduit joined to the mesh material along a lower side and extending in the direction of the length L of the mesh material, and each conduit having a plurality of openings along an upper side opposite the lower side joined to the mesh, material; wherein the conduits of the drain grid are spaced apart and sized to match in assembly with individual ones of the plurality of second openings through the composite outside surface, the conduits of the drain grid joined to the wall structure at the plurality of second openings, such that liquid entering the conduits may be conducted to the second cavities of the blocks forming the wall, and may be transferred between adjacent blocks through the first openings.