How Tokyo’s Giant Tunnels Protect City From Floods

How Tokyo's Giant Tunnels Protect City From FloodsOn the outskirts of Tokyo, behind a small government building, underneath a soccer field and skateboard park, sits a remarkable feat of engineering. It’s an example of how Japan’s capital, which lies in a region at high risk from flooding and tropical cyclones, is trying to figure out how to contain the elements to protect its 13 million inhabitants.

‘Underground Parthenon’

Built between 1993 and 2006 at a cost of nearly $3 billion, the Water Discharge Tunnel is far more impressive than its name suggests. Winding down a series of stairs, you soon come upon a massive hall, resembling an underground Parthenon, or a scene out of a science fiction film.

The initial water tank stretches more than 320 feet in length and towers higher than a five-story building. When you add it all up, the complex features five massive shafts, or tanks, that are able to move water along a tunnel that stretches nearly four miles.

‘Incredible drain system’

In this area of Saitama prefecture, heavy rains would often flood the Naka River Basin. But now, that valuable farmland has an incredible drain system sitting below. When the tanks and tunnel fill, engineers are able to turn on the heart of the system, which is a series of four turbines powered by jet engines similar to those used in a Boeing 737 airplane. The turbines are then able to rapidly funnel floodwaters to the nearby Edo River.

The engineers here are the first to point out that their system, while remarkable, is meant to deal with heavy rains — and that it would struggle to cope with a Sandy-type storm surge.

Do you find Tokyo’s Water Discharge Tunnel an amazing engineering feat? Feel free to share your feedback with us!

Source: Alex Zolbert | CNN

Image: Shine Your Light

EADS’s New Rocket Plane to travel from Paris to Tokyo in 2.5 hours

Earlier this week, one of the biggest European aerospace companies EADS unveiled their ZEHST rocket plane. The ZEHST, short for Zero Emission Hypersonic Transportation, rocket plane is hoping to be able to fly from Paris to Tokyo in just under 2 and a half hours. The plan was for the new rocket plane to be ready for launch by 2050. The plans for the new plane involve ground breaking technology from one of the best aerospace manufacturers in the world.

EADS chief technical officer Jean Botti said that he imagines all planes of the future will look like the ZEHST rocket plane. The EADS future project was announced at Le Bourget airport, a day before the start of the Paris International Air Show. There were several other cutting edge airplanes and technological aerospace advances showed in the Air show. The ZEHST rocket plane was just one of the advances showed by EADS.

The new low pollution rocket plane plans to carry around 50 to 100 passengers from Paris to Tokyo. The plane will be using normal engines that will be powered by bio-fuel made from environment-friendly material such as seaweed. When the plane reaches a high enough altitude, it will switch to its rocket engines and travel at record speeds for passenger flight.

The rocket engines on the ZEHST rocket ship will be powered by hydrogen and oxygen, and the only form of exhaust that will be released by the rocket ship will be in the form of vapor. The rocket plane will be propelled to a cruising altitude of 20 miles or 32 kilometers above sea level. This will be the highest a passenger plane will be travelling, as today’s passenger aircrafts only travel at 10,000 meters.

Botti said that even with the rocket engines, pollution will be minimal because the ZEHST will be located above the stratosphere and all exhaust will be scattered into outer space. To land the ZEHST, the pilots will be cutting off the rocket engines and glide back into the atmosphere before reigniting the regular engines before landing.

EADS is hoping that the prototype will be built by 2020 and the ZEHST rocket plane to enter service to the public by 2050. The project is being collaborated with Japan, which uses technology that is already available there. A four meter model of the plane will be on show at Le Bourget for the biannual aerospace showcase, which begins on Monday and opens to the public on Friday.