About NAKAGAWA HIROSHI
About sewer pipe
About manhole
About water level observation
About cost reduction
About natural energy
About energy conversion
About energy saving
About information system
About private company
About technology development
About interconnection
About internet of things
About power saving
About Sewerage,sewers attached facilities
About IoT
About 下水道
About ゲリラ豪雨
About 対策
About 活用
About 氾濫
About ソリューション