FLOOD CONTROL: BEFORE/ AFTER
WATER DISCHARGE TUNNELS
Japan has used many flood control methods in order to prevent the many typhoons and heavy rainfalls that occur in the country. One of the most popular methods was the Metropolitan Area Outer Underground Discharge Channel (MAOUDC). This is the world's largest underground flood water diversion facility, meant to protect Tokyo from floods. The construction of this tunnel took 13 years (1993-2006), at the cost of nearly $3 billion.
Japan has used many flood control methods in order to prevent the many typhoons and heavy rainfalls that occur in the country. One of the most popular methods was the Metropolitan Area Outer Underground Discharge Channel (MAOUDC). This is the world's largest underground flood water diversion facility, meant to protect Tokyo from floods. The construction of this tunnel took 13 years (1993-2006), at the cost of nearly $3 billion.
Figure 1.1: A diagram of the MAOUDC.
THE GREAT WALLS OF JAPAN
40% of Japan has walls along the coastline to protect from tsunamis and earthquakes in the ocean, the construction costing $9.8 billion. In Minamisanriku, a town in the Miyagi Prefecture, Japan where the tsunami hit, has walls 3-5.5 meters tall. But because the tsunami waves were 7 meters high, it didn't completely protect the town, as seen in the picture below.
Figure 1.2: Minamisanriku, Miyagi Prefecture, Japan.
Figure 1.3: Minamisanriku during the Japanese Tsunami 2011. As you can see, the walls are barely protecting this small town.
NEWEST DEFENCES
Japan's newest defense against floods is a 2-mile subterranean reservoir, still under the $240 million construction.
Japan's newest defense against floods is a 2-mile subterranean reservoir, still under the $240 million construction.