RAINWATER STORAGE DEVICE USING WATER PERMEABLE MATERIAL IN UPPER PART THEREOF AND USING METHOD OF STORED WATER

PROBLEM TO BE SOLVED: To provide a rainwater storage device for storing a great volume of water on the surface of the earth in the ground through a rainwater permeable paving material, prevent damage from flooding or overflow on the surface of the earth, at the same time, utilize water in the rainwater storage device as public use in a vast range, contribute it to the effective use of water resources, accumulate the overflow level in the rainwater storage device in the ground and a water storage tank and to provide a using method of stored water for rationalizing underground protection and reducing load of conventional sewage drain. SOLUTION: Rainwater on the surface of the earth 3 is stored as stored water 11 in a rainwater storage device 1 with large capacity buried in the ground 4 through a water permeable and retentive paving material 2. The stored water 11 in the rainwater storage device 1 is absorbed with a pump 15 through an inlet pipe 16, it is used for public use such as sprinkle, car washing, fire extinguishing, etc., the stored water 11 exceeding the overflow level 18 is led to underground layer 20, conduit pipe 22 and storage tank 23 through a discharge pipe 19 and is restored and discharged.