Installation of rainwater storage facility at the east exit of Shibuya Station

The area around Shibuya Station has a bowl-shaped topography, making it vulnerable to flooding and inundation. In preparation for the recent increase in torrential rains, our company and the Urban Renaissance Agency, as joint developers of the Shibuya Station Block Land Readjustment Project, have been working on the construction of a rainwater storage facility at the east exit of Shibuya Station, aiming to "realize a safe and secure urban development that is resistant to flooding." Construction began in February 2011, and construction was completed and put into service in August 2020 (managed by the Tokyo Metropolitan Government's Sewerage Bureau). The facility is a large-scale structure measuring approximately 45m north to south and 22m east to west, located approximately 25m underground in the underground plaza at the east exit of Shibuya Station, and can temporarily store approximately 4,000m3 of rainwater. When heavy rainfall exceeds 50mm per hour, the water is taken in, and when the weather improves, it is pumped out to the existing sewer main line to prevent flooding damage.

Additionally, Futako Tamagawa Rise, which is located close to the Tama River, has also installed a similarly large underground rainwater storage facility, strengthening the city's resilience against flooding and other disasters and contributing to the creation of a safe, secure and sustainable urban development.

Green infrastructure at Minami-Machida Grandberry Park

Minami-Machida Grandberry Park, which opened in 2019 as a result of cooperation between our company, Tokyu Railways and Machida City, was developed as an integrated development of a station, commercial facilities, and urban park. Based on the concept of "the entire town becoming a park," Minami-Machida Granberry Park is a seamless town with a continuous series of open spaces that combine activity and greenery. By adopting permeable pavement, bioswells, rain gardens, etc. throughout the area, a system has been established to return some of the rainwater to the ground, and rainwater management is carried out using "green infrastructure" that utilizes the functions of the natural environment to develop social infrastructure.

These efforts have been recognized, and the building has received Gold certification from the international environmental certification system "LEED ND (Neighborhood Development Section)." This is the first time in Japan that a building that includes a station has received Gold certification.

In addition, by planting flowers and fruit-bearing trees on the exterior of the commercial facility "Drandberry park," we aim to encourage birds and insects to live there, and to blend nature with lively activity.

Flood damage countermeasures

Measures against flooding damage include raising the level of underground sections to prevent water from entering ventilation openings, installing waterstops to prevent water from entering station entrances and exits, and installing waterproof doors in each equipment room. In addition, a flood response manual has been prepared and training on evacuating trains parked in depots is also conducted. In order to prepare for heavy rains that pose a risk of flooding, weather information is collected daily through the weather information system. Information from anemometers and rain gauges installed at various locations on the Tokyu Line is collected at the Transportation Command Center, which transmits instructions on operational restrictions, including the suspension of operations, and alert systems to each department based on the measured values set out in the regulations. Seismometers are also installed in the weather information system, and both hard and soft measures are being implemented in preparation for not only flooding but also large-scale earthquakes.

Preparing for slope collapse

As a measure against landslides on railway premises, we are promoting construction to reinforce the slopes beside the tracks with concrete, etc., to prevent soil and sand from flowing into the tracks and disrupting operation. Note that this reinforcement work for civil engineering structures is being carried out in conjunction with preparations for natural disasters other than flooding, such as seismic reinforcement work for large-scale earthquakes.