日本多数地区降水丰富,还经常遭遇台风带来的强降雨,因此东京、大阪等大城市十分重视防涝问题。一方面重视城市规划,充分发挥城市水系的防洪功能,增加市内绿地和砂石面积以吸收雨水;另一方面长期投入大量人力、物力和财力,建设较完善的城市排水设施。目前,东京等地的下水道系统已进入新的建 In most parts of Japan, where rainfall is abundant and frequent heavy rainfall from typhoons, major cities such as Tokyo and Osaka attach great importance to waterlogging prevention. On the one hand, attention to urban planning, give full play to the flood control function of urban water system, increase the city green area and gravel area to absorb rainwater; the other hand, a lot of manpower, material and financial resources to build a better urban drainage facilities. At present, sewer systems in places like Tokyo have entered a new construction