| 摘要 |
PROBLEM TO BE SOLVED: To provide a permeation basin capable of excellently making rainwater in a site flow in the ground, without causing looseness of the natural ground of a permeation basin lower part.SOLUTION: A permeation pipe 3 for penetrating through a basin member 2b of a bottom part of a storage tank 2, is provided in the almost center of a bottom surface of the storage tank 2 of a permeation basin 1. This permeation pipe 3 comprises an unperforated part 3a of not forming a permeation hole for permeating rainwater and a perforated part 3b for forming a plurality of permeation holes 3bh. The permeation pipe 3 is installed so that a boundary BP between these unperforated part 3a and perforated part 3b becomes a position equal to a variation upper limit position of an underground water level WL or deeper than that.SELECTED DRAWING: Figure 7 |
