How do major cities in the world seize and reuse rainwater?

Depending on how we receive it, rainwater may be a gift or a burden. Heavy rains cause flooding and increase pressure on the city's infrastructure, but it is also a free source of water that can be used for many other things.

People from the beginning of the site, began living with nature and sought to control nature to exploit their benefits. In modern times, cities in the world also have to find ways to turn extremes into resources and to protect their citizens from the wrath of mother nature.

Looking at the world, many large cities have invested huge drainage systems to reduce pressure on infrastructure, as well as reuse that water source for green park items. Here is how the world takes advantage of water from heaven very creative and effective.

Great underground sewer works help Tokyo no longer flooded for the past 20 years

Japan is known as a country often affected by natural disasters, is an island stretching from north to south, mountainous terrain accounts for 75% of the land area. Whenever heavy rains, the rivers here are easy to overflow causing flooding.

For this reason, with limited land area, Japan has built an underground drainage system under cities. This system is the largest underground drainage facility in the world.

A sub-city below Tokyo helps receive rainwater and processes them.(Photo: Edogawa government office).

At a depth of 50 meters underground in Saitama Prefecture, on the outskirts of Tokyo, the great underground sewer that took 17 years to build in Japan still receives huge amounts of water from the ground every day and carries them everywhere.

Started in 1992, this project was put into operation in 2006 and officially completed everything in 2009. The system consists of 5 large cylindrical axes with a diameter of about 30m - wide enough to accommodate a submarine . All of them are connected by a curved design tunnel, 250m in diameter, 6.3km long.

The central lake in the giant underground sewer system controls the water volume of the entire system.

At the end of the system, water will be stored in a giant pressure control reservoir. This lake has the function of reducing the pressure of flowing water, as well as controlling the flow of water in case of a broken pump. The reservoir is 177m long, 78m wide and about 22m high underground - wider than a football field.

The system is capable of discharging 200 cubic meters of water per second to the Edo River and quickly draining water in the inner city. The heaviest rain ever received by the system in the following year has helped it to perform well its capacity, 12 million cubic meters of water have been drained and helped Tokyo avoid flooding.

The water pipes here can accommodate a NASA space shuttle, helping Tokyo see no more flooding for more than 20 years.

The amount of water received from the city will be pushed to the Edo River and downstream and then to the sea. But not all recipients are discharged, but the reservoir has the duty to store it to reuse rainwater in the dry season. This super giant underground sewer system has helped the city of Tokyo no longer have flooding for over 20 years.

Dams have prevented flooding, while creating electricity for the entire village to use

The Rhine is a large river in the Netherlands, it has a large flow of water, a very strong flow of water and frequently causes flooding in the village of Hagestein on both sides of the shore when water from the upstream flows too much. As a small village located not far south of Amsterdam, Hagestein holds an important position but is often threatened by nature because it is located downstream.

The giant dam on the Rhine in the Netherlands, helps to overpower the flow of water and generate electrical energy for thousands of households.(Photo: Getty Images).

In light of this fact, the Dutch government built Hagestein Weir, a large dam that blocked the river before it entered Hagestein. The dam has been in operation since the 1960s and helps regulate river water before going deeper into the inner city.

Dams Hagestein Weir has two giant arches that regulate the flow of water and use the force of the water to generate electricity, powering the entire village of Hagestein. Each of the dam's arches extends to 54 meters, an electric turbine mounted on it creates 3.5 MV of electricity and lights thousands of households on both sides.

The two archways are raised and laid down in the river flexibly to regulate the flow.(Photo: Flickr).

Along with Hagestein Weir, there are two other dams on the Rhine River, Nederrijn and Lek, these three dams operate in a harmonious way to help the water flow into the inner area at a sufficient level, and boats are stable and stable. creating electricity for villages on both sides of the shore.

Tunnel 2 in 1 in Malaysia

Stormwater Management and Road Tunnel (SMART) is a cumulative flood drainage road in the capital Kuala Lumpur, Malaysia. This 9.7km, 13m wide tunnel leads to water out of Kuala Lumpur after heavy rains, while the 3km middle section acts as a two-level highway.

Two-storey highways in Kuala Lumpur, both help reduce traffic pressure, both store rainwater and avoid flooding.(Photo: The Star).

When it does not rain, the tunnel operates normally to allow traffic. When the rain is small, the tunnel is placed in the semi-open mode that leads the rainwater to flow through the lower floor of the highway, the vehicles can still use the upper floor.

When there is heavy rain or heavy thunderstorms, too much water falls and there is a risk of flooding in the city, the tunnel changes to full open mode. Automatic water doors open for water to flow through and vehicles are prohibited from crossing the tunnel.

When the rain is too big, both floors of the highway will be used as a storage area for rainwater.Rainwater will be reused for public items in the city and quickly removed after a sunny day.(Photo: The Star).

The amount of water on the lower floor of the road is stored and used for green park items in the city. This amount of water quickly disappears after a sunny day and the road will continue to be open for traffic. With the construction cost of US $ 500 million, SMART is the first road tunnel in combination with flood drainage in the world.

Future technology of smart cities

In an effort to build a smart city in Toronto, Sidewalk Labs is Alphabet's subsidiary that has created an intelligent system that helps to protect the sun and rain automatically, helping people walk in public areas. the weather was not wet and the trip was interrupted.

Future smart cities will use a giant dome to shield public areas from storms and rain, the amount of rain outside the dome will flow to the sewers outside the city and reserve for other work.(Photo: Sidewalk Labs).

According to the design, some public areas such as squares, parks or streets will be equipped with giant domes above. When the sensor system knows that it is raining, the dome will open and cover the area below, helping these places not get wet and people continue to live as usual.

The amount of rainwater will be concentrated on a treatment center and then pumped into the public water system and served for other items in the city, helping to save water through the reuse of natural water. This project helps people feel free to go out at any time without having to be afraid of rain or wind.