G cans project report
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G cans project report
- 1. 1 1.0 INTRODUCTION The Tone, Are and Edo Rivers had been terrorizing the people of greater Tokyo for generations with their periodic monsoon-season flooding and Typhoons. In September 1991, the worst storm to strike Japan in 30 years. 30 000 homes and 100 square kilometres (25 000 acres) of land in the low-lying northern suburbs of Tokyo were flooded, causing a total of 52 deaths in Japan. The question arises How can we prevent flooding and water damage in area like Tokyo ,the answer was not to concentrate just on river improvement but instead to create comprehensive flood control measures for the basin as a whole .Comprehensive flood control measures include river and sewage system improvements but also the construction of special storage facilities that can store runoff water in the urban area and prevent it from flowing into rivers causing them to overflow their banks .That’s why flood control channel storage facilities have been built. To protect the city’s 13 million residents from heavy rainfall and tropical storm floods, The simplest solution would have been to build a reservoir. But the question facing urban planners was :- How to build a reservoir In a city twice as dense as New York ? The answer : Build it underground. The results were Metropolitan Area Outer Underground Discharge Channel. Completed in 2006 G Cans gathers the overflowing floodwater from the rivers in Tokyo such as OochiKotone, Kuramatsu, Nagakawa and Arakawa, and drains it into the Edogawa River. The place is also used for guided tours or filming movies and commercials, although this may suspended depending on the weather. Some people have suggested that this ¥230 billion project is something of an overkill – perhaps designed more to line the pockets of Japan’s construction industry than to keep anyone’s feet dry, but there was certainly a need for something. In 1991, two years before construction began, 30,000 homes around the northern fringes of Tokyo were flooded by a typhoon, and it was predicted that a once in two hundred year extreme deluge would flood almost 100 subway stations. G-Cans took 17 years to build, and since its completion in 2009, it’s massively reduced flooding. No doubt Tokyo residents whose homes frequently used to end up underwater think it’s money well spent.
- 2. 2 2.0 FLOOD A flood is an overflow of water that submerges land that is usually dry. Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. Some floods develop slowly, while others such as flash floods, can develop in just a few minutes and without visible signs of rain. Flood caused by river overflow has the potential of sweeping everything in its path downstream. Lake and Coastal flooding occurs when large storms or tsunamis causes the water body to surge inland. The immediate impacts of flooding include loss of human life, damage to property, destruction of crops, loss of livestock, and deterioration of health conditions owing to waterborne diseases. 2.1 JAPAN’S HISTORY WITH FLOODS Tokyo, and the rest of Japan, has a long history of devastating and deadly floods. A storm in 1910 destroyed 4.2% of the nation’s GDP. And storms throughout the 20th century left the rapidly urbanizing nation’s cities and towns underwater. And just last year, floods ravaged cities in Japan’s northern regions. Fig no - 1
- 3. 3 3.0 PROFILE Address:- Showa in Tokyo to Saitama, outskirts of the Greater Tokyo Area. Purpose: - Flood Control Dimension of silo: - 65 m height, 32 m diameter. No of silos :- 5 Dimension of tunnel :- 6.3 m long Dimension of water tank: - 25m height, 180 m length, 80 m width. No of turbines :- 4 Type of Turbine:- Jet engine turbine. No of pillars in water tank :- 59 World record:- world's largest underground flood water diversion facility. Engineer :-Japanese Institute of Technology and Engineering Sewage Owner :- Government of Japan Construction Cost:- $3bn Construction started:- 1992 Project Completion :- 2009
- 4. 4 4.0 WHAT IT IS & WHY IT IS MADE? Ever wonder why Tokyo does not flood? Next time when you are walking around the Japanese capital, stop for a minute to consider this, Just 50 meters below the ground is a labyrinth of tunnels and massive pumps that can remove 200 tons of floodwater every second. It has been described as the biggest underground man made drainage system in the world. With around 30 percent of Tokyo’s population living below sea level, mostly along Tokyo bay or many rivers that feed into it, the metropolis has had a long history of disastrous flooding. As the capital city grew and Japan prospered, protecting the world largest metropolitan economy and its inhabitants – over13 million in Tokyo today and more than 36 million in the greater metropolitan area – become a national priority. The Tone, Are and Edo Rivers had been terrorizing the people of greater Tokyo for generations with their periodic monsoon-season flooding and Typhoons. In September 1991, the worst storm to strike Japan in 30 years. 30 000 homes and 100 square kilometres (25 000 acres) of land in the low-lying northern suburbs of Tokyo were flooded, causing a total of 52 deaths in Japan The simplest solution would have been to build a reservoir. But the question facing urban planners was: - How to build a reservoir In a city twice as dense as New York ? The answer : Build it underground. The results were Metropolitan Area Outer Underground Discharge Channel, also G-Cans, and more recently the Furukawa Underground Regulating Resulting Reservoir. The Metropolitan Area Outer Underground Discharge Channel gathers the overflowing flood waters from rivers in Tokyo, such as OochiKotone, Kuramatsu, Nagakawa and Arakawa, and drains it into the Edogawa River.
- 5. 5 fig no -2 The aim was simple: to take all the excess rainwater from typhoons and floods away before it can cause any damage. The way it was implemented is also simple – they built a big drain. But the enormity and engineering complexity of the construction is staggering. Under the floor of Tokyo, underground, unfolds a landscape worthy of any great imagination, the G-Cans Project, the sewage of the city. Started in 1992 at a cost of 1,500 million euros, was built to avoid the heavy rains, especially in times of Monzón, and even a Sutnami, can cause major flooding in the Japanese capital, for the purpose of bone to collect enormous amounts of water. The place is also used for guided tours or filming movies and commercials, although this may be suspended depending on the weather. 4.1 LOCATION:- The government of Japan has made possible this feat through the Japanese Institute of Technology and Engineering of sewage, which together with the private sector has built a veritable underground city in Edogawa City, Saitama region, one of the great neighborhoods or areas of Tokyo.
- 6. 6 5.0 WHAT IT DOES & HOW IT WORKS? The metropolitan area outer underground discharge channel is not only equipped with temple like water tank but also has shafts and a massive underground waterway connecting to rivers in the region ,the total length reaches 6.3 km. 5.1 DUCT When river water exceeds a certain level it starts flowing into ducts Fig no -3
- 7. 7 5.2 SILOS It has 5 silos with a diameter of 32 meters and 65 meters in height, connected by tunnels along the 6.3 km. The water been channelled underground through the shaft (5 in all). These shafts are big enough to fit the space shuttle or the statue of liberty. Fig no - 4
- 8. 8 5.3 TUNNEL Total length :- 6.3 km • The water in the shafts then flow to the underground tunnel ,the tunnel is about 10m in diameter ,it was excavated by a massive shield machine a technology in which Japan is a world leader . • The tunnel was bored using the shield method in order to avoid distortions due to its depth. The work included excavation, construction of lining and muck transportation. • The vast diameter of the tunnel also necessitated the application of a closed type slurry shield method. • Modern technologies were applied for the secondary lining of the tunnel to cut the cost of construction. • Water-tightness is maintained within the tunnel with the help of internal water pressure reacting type segments. Fig no - 5
- 9. 9 5.4 THE PRESSURE ADJUSTING TANK The main tank measures 180 meters long and 80 meters deep b 25 meters in height (about the size of soccer field ). When even more water drains into the channel, it is sent to the tank designed to adjust water pressure. The depth of the storage tank is equivalent to height of fifth or sixth floor of building. It is the space almost looks like a Greek temple. Visitors can tour the pressure adjusting tank after listening to the explanation of the discharge channel. Fig no - 6 5.5 COLUMNS Each of its 59 columns weighs 500 tons and all are connected to 10MW pump capable of moving 200 tons of water per second to the Edogawa River.
- 10. 10 5.6 CHANNELS AND TURBINES It can move its channels to 44 million liters. The system is powered by 14,000 turbines which can pump up to 200 tons of water per second. Each turbine uses the same energy as the engine of a Boeing 737. These giant aqueducts are in operation when the rainfall exceeds the limit that can generate these floods and excess water are transported mainly to the Edogawa River and several smaller rivers along 6.3 kilometers When the water level in the tank rises, modified jet turbine pumps go into operation to discharge water from sewer system. When all four pumps are operating, 200 cubic meters of water (equal to 25-m swimming pools) can be discharged per second. Fig no - 7
- 11. 11 • Water is discharged into a large and wide Edogawa river through a sluice. • Water in the silos and tunnel is discharged by pumps installed in each silo after the rain stops. • Number 3 and no 5 shafts have a handle a large amount of water so their structure is designed spiralling to drive the water to the walls using centrifugal force • This slows the water and reduces impact when it hits the bottom of the shaft. Fig no -8 6.0 STRUCTURES AND MATERIALS The excavation is an extreme example of cutting edge technology .Its engineering is most innovative structures and materials ,combined with tons of concrete . the tunnel is about 10m in diameter ,it was excavated by a massive shield machine, a technology in which Japan is a world leader .
- 12. 12 7.0 IMPACT ON URBANIZATION Tokyo and the surrounding area are much safer. The risk to homes, businesses and public services has reduced significantly. Making the area safer has encouraged more growth and even more urban sprawl. This is creating new problems. Super levees designed to create public walking areas and shopping centers have played a part in new developments moving into areas that are historically flood prone. It seems the system designed to protect Tokyo from floods has been so successful it is encouraging growth into danger areas still relatively unprotected. 7.1 STILL A THREAT Continued urban expansion, the recent rise in storms across east Asia, and the prospect of further changes from climate change has city planners worried. Particularly when it looks like the system is being overwhelmed in some areas. Video shot in 2011 by a Tokyo resident of the above ground drain systems (supported underneath by the G-Cans Project) during a typhoon shows what the city is still facing. 8.0 THE FURUKAWA RESERVOIR In 2008, Japanese urban planners recognized that increased urban sprawl required a flood control solution beyond the G-Cans. The Furukawa Reservoir would utilize old and new concepts to protect the fast growing metropolis. Similar to the above ground discharge waterways, the system would focus on moving water from flood areas into rivers that could carry the water to the ocean. Instead of giant cisterns, the system would use 3.3 kilometers of 7.5 meter diameter tunnels. But like the G-Cans system, the Furukawa project would be entirely underground. “What makes this system particularly noteworthy is just its scale, because it’s underneath one of the largest cities in the world,” said Patrick Lynett, a civil engineering professor at the University of Southern California in Los Angeles. “It allows them to have this flood control out of sight.”
- 13. 13 “Japan has no choice. With the lack of space they have, they have to come up with some ingenious way of doing this,” Marcelo H. Garcia, director of the Ven Te Chow Hydrosystems Laboratory at the University of Illinois at Urbana-Champaign, told the Japan Times. The project should be completed later this year. It is a feat of construction only matched by its G-Cans peer. Starting with its connection to above ground water collection systems. fig no -9 When finished, water will be able to be pumped away from metropolitan areas, protecting lives and property. The full capacity of the Furukawa Reservoir is expected to surpass 135,000 cubic meters of water, about the equivalent of 54 Olympic-size swimming pools. 8.1 A LESS WATERLOGGED FUTURE Completion of the Furukawa Reservoir is the second of three major underground flood control projects in Japan’s capital region. In the next few years, a third system featuring another 3.2 kilometers of massive tunnels in the northwest of Tokyo will be complete. While the cost of these systems may not be reasonable for most countries, the concepts and lessons learned will be essential in a more and more urban world facing increasing threats from climate change.
- 14. 14 9.0 VISITING G CANS THE TOUR Naturally for such an awesome spectacle, the Water Discharge Tunnel on the Outskirts of the Metropolitan Area has attracted great tourist interest. Visitor numbers are limited for the regular tours (in Japanese only) and advance bookings are essential Upon arrival at the site one registers in the visitor Centre, where a wide variety of G- Cans related displays are on show. At the designated time a tour guide arrives with clever personal speaker system to introduce the tour. • Visitors can tour the pressure adjusting tank after listening to the explanation of the discharge channel. • The place is also used for guided tours or filming movies and commercials, although this may be suspended depending on the weather. • Tours of G-Cans are popular with people of all ages, including plenty of children. They’re conducted in Japanese, but you won’t miss much as the commentary is really boring and repetitive. Each tour starts with a video and a look at an exhibition, before getting to the good part – entry to the temple. You go in through a small concrete building that slants into the ground. Inside a staircase winds down and down, eventually emerging on one side of the giant chamber, from where you can descend to the floor. You’re not allowed inside the silos or the tunnel – they’re for employees and VIPs only – but you do get a good view of one silo, which is adjacent to the temple. • Tours run three times a day, Tuesday to Thursday, and last an hour and a half. They can be booked via the official website, but you must be accompanied by someone who can speak Japanese, so they can translate evacuation instructions in case of an emergency. Tours begin at the pump station in Kasukabe City, just meters from the banks of the Edogawa river. It’s about 35 kilometers north of central Tokyo, and can be accessed from Minami Sakurai Station on the Tobu-Noda line. The journey takes around an hour and ten minutes by train, then it’s around half an hour’s walk.
- 15. 15 Fig no -10 Fig no - 11
- 16. 16 10.0 CONCLUSION • Flood tunnels are an important part of flood and storm water management system. They are used where space is limited – often in urbanised areas such as Tokyo, or in Kualur Lumpur. • The Metropolitan Area Outer Underground Discharge system was built to handle flooding from monsoon-season typhoons and has been used over 200 times. • Government figure said, the project likely saved around 430 million dollars in property damage alone since it become fully operational. • The metropolitan area outer underground discharge channel provides a cost effective solution • Around the world there are regions suffering from flood damage much like Japan, with its introduction in Indonesia this technology is starting to aid in global flood control efforts.
- 17. 17 REFERENCES • "LAIR OF THE BALROG". Accessed 10 January 2015 • Jump up^ "CNN How giant tunnels protect Tokyo from flood threat". • Jump up^ "G-Cans: Tokyo's Massive Underground Storm Drain". • Jump up^ "G-Cans Project, Kasukabe, Saitama, Greater Tokyo Area, Japan". Retrieved 10 January 2015 • Jump up^ http://www.ktr.mlit.go.jp/edogawa/gaikaku/english/index.html • Jump up^ "Catalyst: Tokyo Flood Prevention - ABC TV Science". ABC - Australian Broadcasting Corporation (Video Documentary). 2014-10-23. Retrieved 2015-03-20.