Imagine being in these tunnels when a flood hits,(reply>), you would probably get wet,(reply>), @Ilya Holt I had a good laugh at this comment. While there is unlikely to be an event that can instantly fill this facility, however it does handle huge volumes of water. So to help with some perspective on what this is designed to handle - powering the pumps are turbines which are modified from jet aircraft engines. The pumps can themselves pump out 50 cubic meters of water 'per second'. The facility at the end of the line has 4 such pumps so that enables them to pump out 200 cubic meters of water. For americans - that equates to 52,834 gallons of water per second. For others thats 240,000 ltrs per second. <br>Wall of water does not come close to explaining what that will look like as you would spend a few seconds perceiving things and that would add 52K gallons every second...,(reply>), It would fill up fast when a tsunami hits Tokyo,(reply>), jammygiinger no 😱,(reply>), Thousandth like