Abstract: There is provided by the invention a subsurface drainage system which promotes efficient and controlled subsurface drainage of fluids, such as irrigation water, applied to the surface of land such as a football field. A drain core apparatus is provided that provides rapid infiltration and later movement of subsurface fluids, but which is resistant to settling, compacting and crushing. The drain core is a thermoplastic mat having crush-resistant support members integrated with and upon a backing grid which holds the support members in spaced relation to one another. Fluid flowing into and through the drain core is collected and stored in a fluid storage container. The fluid storage container is adapted to be buried beneath the ground, and has an easily assembled internal support structure composed of vertically layered thermoplastic mats. The mats permit fluids to flow freely within the container, and yet lend vertical and structural stability to the container.

Abstract: There is provided by the invention a subsurface drainage system which promotes efficient and controlled subsurface drainage of fluids, such as irrigation water, applied to the surface of land such as a football field. A drain core apparatus is provided that provides rapid infiltration and later movement of subsurface fluids, but which is resistant to settling, compacting and crushing. The drain core is a thermoplastic mat having crush-resistant support members integrated with and upon a backing grid which holds the support members in spaced relation to one another. Fluid flowing into and through the drain core is collected and stored in a fluid storage container. The fluid storage container is adapted to be buried beneath the ground, and has an easily assembled internal support structure composed of vertically layered thermoplastic mats. The mats permit fluids to flow freely within the container, and yet lend vertical and structural stability to the container.