OPTICAL FIBER NETWORK ESTABLISHMENT IN NAGOYA

Fiber-optic cables installed in sewers are well protected from damage caused by earthquakes, fires, lightning, violent winds and flooding. They can therefore ensure stable and accurate communication of information even at the time of such disastrous events. In addition, since already existing sewers are used, it is possible to construct communication networks in a short period of time. Recognizing these advantages, many municipal governments in Japan, mainly in large cities, have routed fiber-optic cables through sewers, their total length reaching some 1,000 km as of the end of fiscal 2001. In the City of Nagoya, the Waterworks & Sewerage Bureau began to install fiber-optic cables in sewers in fiscal 1999, for the remote control of stormwater pumping stations. The total installed cable length is approximately 50 km as of the end of fiscal 2003.At present, these in-sewer fiber-optic cables are also used for the Storm Drainage Information System, which can provide the Headquarters with real-time information about the operation status of each stormwater pump. This system enables operators to grasp various kinds of information, such as pump operation status, emergency deployment status and river water levels, in real time.Recognizing the superior data-transmission capabilities of fiber-optic cable, such as large capacity and high speed, the Waterworks & Sewerage Bureau is also proceeding with utilizing in-sewer fiber optical networks for the Bureau's budget and settlement management system, as well as for the office intranet. In an attempt to computerize administrative services, the Nagoya municipal government is now engaged in constructing an administrative information network which connects the city hall with each ward office using the optical fiber networks in sewers in conjunction with those installed along subway rail tracks.