Kentaro NAGAI Performance change of wells for snow melting facilities caused by direct recharge of water Hirofumi TOYOTA In recent years, a localised torrential downpour, which heavily rains in the limited area for a short time, has been frequently occurring. Since the occurrence of this downpour is difficult to predict in contrast to a typhoon etc., landslide and flood disasters are easily caused during the downpour. @Then, in our laboratory, it is proposed that rain water is directly pour to a well for snow melting facilities as a measure against inland flood with low cost and easy to practice. The injection capacity of the well and the small effect of injection on circumference were verified from previous studies. In this study, injection and pumping tests were conducted in order to verify gappropriate evaluation of the injection capability at different wellsh and ggrasping the actual conditions of clogging mechanism of wellsh, which are problems remained at previous studies. The main results are summarized as follows: 1.The water level of the circumference wells slightly rises during injection and promptly falls after the end of injection. 2.The injection capacity of Well-23 is respectively 180 L/min and 1000 L/min with and without a water pump. 3.The reduction of injection capability by the water pump is dependent on a original permeability of the ground, and its reduction is large when the permeability of the ground is high. 4.Although the iron bacteria, which are considered as clogging substances, generate after the injection, the clogging substances can be removed by pumping water.