Patent ID: 7811030

Claim:
In a water drainage system for a field having a water-impermeable layer and an underlying water-permeable layer beneath said water-impermeable layer, the combination of a plurality of horizontally disposed drainage elements disposed in a linear array within a layer of soil above said water-impermeable layer, each said drainage element having a mass of light weight discrete aggregate defining passageways for a flow of water therethrough and a sleeve encasing said mass of discrete aggregate; and a plurality of vertically disposed drainage elements below said horizontally disposed drainage elements for receiving flows of water therefrom and passing through said water-impermeable layer into said water-permeable layer to dissipate the flows of water into said water-permeable layer, each said vertically disposed drainage element having a mass of light weight discrete aggregate defining passageways for a flow of water therethrough and a sleeve encasing said mass of discrete aggregate.