| 摘要 |
PROBLEM TO BE SOLVED: To grasp concentration of harmful substances originally contained in ground water without newly installing an observation well for grand water collection.SOLUTION: In a collection method of ground water according to the present invention, first, a casing 1 is erected in a drilling hole, while forming a drilling hole 3 in a ground 2 (step 101). Next, a gravel 12 is filled into an inner space of the casing 1 in such a manner of being piled up on a drilling bottom 11 located in the lower end vicinity of the casing 1 (step 103). Next, with a filling height h of the gravel 12 as an upper limit, the casing 1 is pulled up (step 104). Next, the grand water which flows into the drilling hole 3 from a porous wall 13 and the drilling bottom 11 and further flows into the casing 1 by passing through a gap of the gravel 12 is collected (step 105). When the grand water is collected, the casing 1 is pulled up and removed (step 106). |
