. Fujitsu Limited and Fujitsu Kyushu Network Technologies Limited (collectively "Fujitsu") today announced the start of sales in Japan of their Sewer System Flood Detection Solution, aimed at reducing the damage from torrential rain and flash floods.
This solution uses a sensor attached within a sewer manhole to collect water-level data, and wireless communications that transmit this data to the cloud every five minutes(1). The sensor is powered by a thermoelectric converter that turns energy from temperature differentials into electricity. The converter, developed by Fujitsu Kyushu Network Technologies, extends the time between battery replacement from 10 months with the sensor being powered by batteries alone, to five years(2). This means that in addition to making it possible to achieve dramatic operating efficiencies, deployment costs are also kept in check as power supply installation is unnecessary.
This solution can quickly detect sudden rises in the water level in drainage pipes, enabling rapid measures to limit damage resulting from flooding accompanying locally concentrated downpours. In addition, accumulated water-level data can be useful in evaluating sewer drainage plans and setting system-renovation plans.
In recent years, higher levels of urbanization and numerous instances of torrential downpours have caused increasingly extensive flood damage. There has also been a demand for the rebuilding and expansion of drainage systems and faster data collection as flooding countermeasures. In particular, under Japan's Flood Control Act, which was revised and put into effect in fiscal 2015, water-level notification systems have been established for areas neighboring drainage systems, such as underground shopping malls.
One method for measuring water levels in drainage pipes uses fiber optics; however, it is necessary to lay dedicated cables to the measuring point, requiring high deployment costs. Meanwhile, in the method involving the installation of battery-powered water-level sensors to the bottom of manhole covers, frequent battery changes are required, creating an issue with maintenance costs.
The solution's hardware was commercialized by Fujitsu Kyushu Network Technologies, based on R&D by Fujitsu Laboratories Ltd. and a fiscal 2015 field trial with the city of Koriyama in Fukushima prefecture. This solution limits systems deployment and operations management costs, and contributes to reductions in damage caused by flooding of drainage systems.