
NEW FLOOD TECHNOLOGY
In a recent post I commented on the flood prevention technology being utilized in the subway stations of Nagoya, Japan. The floodgates are designed to protect the subway system from suffering extensive damages during a flood event. However, my contention is that any preventative measure that requires human activation and /or electricity to operate, suffers a potentially fatal flaw.
What if the power goes out? What if no one is around at the time the switch needs to be flipped?
I believe there is a better solution. The downside to floodgates, from my standpoint, is that they would require constant maintenance and human intervention to be properly implemented during a flood. What else could the city do to offer protection? Build cement steps at the entry of the subway, rising up several steps, before leading to the down staircase. A full time cement barrier. They would not be susceptible to mechanical failure or require any personnel to implement them during a flooding event. Yes, they would be expensive to build, but far less expensive than the seawater swirling around in the subway tunnels caused.
This flood prevention model has been utilized in some residential settings as seen in the picture below:

Notice the doorway in the photo above, under the exterior light fixture. In order to reach the door, you must first ascend several steps before going down several stairs to reach the door. This works to create a flood barrier protecting the entry door on all sides. This same idea could be extrapolated for use in the subway system design thereby creating a permanent flood barrier.
I’m not suggesting this idea comes without it’s own downsides (they would be cumbersome for many people to navigate, for starters), but they would always be at the ready. As an added benefit, they’d also serve as a permanent visual reminder of flooding that has occurred in the past – revealing their own cautionary tale, lest anyone forget.
AQUA FENCE

Link to article about the Japanese subway system floodgate: en.rocketnews24.com/2013/09/06/nagoya-surprises-citizens-by-unveiling-new-flood-prevention-technology/