渋谷駅地下に巨大貯留施設　豪雨時の浸水防止―東京

　東京・渋谷駅の地下約２５メートルに東急が整備した巨大な雨水貯留施設が１９日、報道陣に公開された。約４０００トンの雨水を一時的にためられ、豪雨時の浸水被害を防ぐ。３１日から供用を開始し、東京都下水道局が管理する。
　東急や都によると、１９９９年８月の大雨では渋谷駅地下街が浸水。駅はすり鉢状の地形の底に位置し、雨水がたまりやすいことが課題となっていた。（2020/08/19-19:23）

A huge rainwater storage facility built under Shibuya Station in Tokyo by Japanese railway and real estate group Tokyu Corp. was unveiled to the media on Wednesday.
   The facility, located some 25 meters underground and managed by the Tokyo metropolitan government's sewage bureau, can temporarily hold about 4,000 tons of rainwater to prevent flood damage from heavy rain. It will go into service on Aug. 31.
   Construction started in February 2011 as part of a redevelopment project for areas around the train station. The storage space is 7 meters in height, and measures 45 meters from north to south and 22 meters from east to west.
   Rainwater will be sent to the storage facility from sewage pipes once the amount of rain exceeds 50 millimeters per hour. The system is capable of handling rainfall of up to 75 millimeters per hour.
   Stored rainwater will be pumped back into sewage pipes after weather improves, with the work taking up to two days.