grade application it is to be understood that the earth could be graded to provide the desired slope in the present invention use is made of substantially planar geometrically symmetrical and repeating double cusp geocomposite material such as that shown in fig4 and disclosed in u s pat no 4 639 165 double cusp geocomposite material 16 used for overall water drainage and double cusp geocomposite material 18 used for perimeter drainage and which is of a larger size that drain 16 is shown in an exploded view in fig4 also shown is the wrapping of water pervious geosynthetic filter material 20 about perimeter drain 18 and the single top covering of the water pervious geosynthetic material 20 covering drain 16 the water pervious geosynthetic fabric is overlapped at the junction of drain 16 and perimeter d rain 18 shown generally at 28 in fig4 during installation this overlap junction is preferably glued or otherwise fastened to insure placement during use it is to be understood by those skilled in the art that the geocomposite material can be of the double cusp variety 16 18 as shown in fig6 amp 6a or the single cusp variety 17 shown in fig7 amp 7a other geometrical shapes and combinations are possible however experience has shown either the single or double cusp designs to be the most efficient when the single cusp geocomposite material 17 is used as shown in fig2 a amp 3a adjoining rows may be overlapped at least one row or more as shown at 47 in fig5 to.