Patent ID: 8753036

Claim:
A liquid retention system comprising: a plurality of pipes, each pipe having a wall defining a pipe conduit, at least some of the pipes having at least one hole through the wall for allowing liquid to enter the conduit; a first pipe group comprising a first layer of the pipes and a second layer of the pipes, the pipes in the first layer being arranged in adjacent proximity along their lengths such that the walls of adjacent pipes define a plurality of gaps, the pipes in the second layer being at least partially seated in the gaps; and a second pipe group comprising a third layer of pipes and a fourth layer of pipes, the pipes in the third layer being arranged in adjacent proximity along their lengths such that the walls of adjacent pipes define a plurality of gaps, the pipes in the fourth layer being at least partially seated in the gaps; wherein: the first and second pipe groups are arranged in a liquid retention portion, the liquid retention portion being at least partially enclosed to retain liquid therein; and the cylindrical axes of the pipes in the first pipe group relative to the cylindrical axes of the pipes in the second pipe group are non-parallel.