Thousand years of Dutch life against flooding by squeezing water for soil

We are not alone in the fight against flooding. Many countries such as the Netherlands, Italy, Japan, Singapore . Thailand and Thailand are also committed to flooding and more importantly, they have been more or less successful.

Building sea embankments

Oosterscheldekering sea barrier (embankment of Schelde East storm) is over 3km, connecting two small islands in the Netherlands - (Photo: readesl).

Currently, 27% of the Netherlands is below sea level and 60% of their population is vulnerable to floods.

In the Netherlands, there are about seven types of dykes and embankments dedicated to the sea, rivers, lakes, canals, or emergency dykes, storm-resistant dykes . built appropriately depending on the use.

The Netherlands has a system of dykes in the North Sea with the name of the North Sea protection project - which is still called the 8th wonder - in two parts: one named Zuiderzee and one named as a delta project.

Zuiderzee project was started in 1923 because after the terrible storm in 1916, the Dutch government had to think about building a dam at Zuiderzee Bay - which is a 100km long, 50km wide port but only 5m deep .

Normally, Zuiderzee has a lot of fish and is peaceful but when there is a storm, it becomes aggressive, causing many internal dykes to break.

The main part of the Zuiderzee project is a 32km long, 100m wide and 8m high dam, blocking water from entering the North Sea into Zuiderzee and gradually turning it into a freshwater lake, named Ijsselmeer.

Not only solving the problem of water barrier from the North Sea, Zuiderzee also helped Dutch people get more than 1,500 km ^{2 of} land in the Ijsselmeer area to build modern and developed cities today.

Close up of the embankment of Oosterscheldekering - (Photo: 7wonders.org).

Meanwhile, the delta project was completed in 1987, worth $ 7 billion. This work consists of 13 dykes, large and small embankments, of which Oosterscheldekering (Schelde's winter storm shield) is the largest.

The main part of Oosterscheldekering is longer than 3km including 62 steel doors, each 42m wide, weighing 300-500 tons, supported by 65 concrete columns - each column is 35-38.7m high and weighs an average of 18,000 tons.

Above these doors are a concrete road for vehicles connecting two small islands. Normally these doors are open but when the sea level rises when there is a storm, people will close these steel doors.

The reason for the Dutch to build Oosterscheldekering is because of the huge storm in 1953, killing 1,800 people, 72,000 people were evacuated and 10,000 houses were damaged. The unprotected southwestern region of the Netherlands is seriously affected.

The world's largest mobile shield in the Netherlands - (Photo: rotterdamexperience).

For more than 1,000 years, the Dutch people have always had to deal with water to keep their small areas dry enough to cultivate. They have to do two jobs simultaneously, build sea dykes and build flood protection embankments from the river.

In addition, in the dyke and embankment system of the delta project, it must also include the Maeslant storm barrier , the latest component added to the delta project in Rotterdam. The project consists of two gates, each 22m high, 210m long, 6,800 tons weighing, can be opened. This is also the largest mobile barrier in the world.

Living with floods

Not only have to deal with the influx of water from the North Sea, the Dutch also have to deal with the rising flood waters due to the delta of three Rhine, Schelde and Meuse rivers and many other tributaries. All these rivers flow into the North Sea.

During the 20th century, the Dutch diligently built embankments along the river to prevent flood water. In 1977, there were many warnings about weaknesses in the embankment system, but then the government did not change its mind because the solution required a lot of house clearance. And the Dutch suffered the consequences when two floods in 1993 and 1995 caused 200,000 people to evacuate.

This forced the Netherlands to consider a solution called Room for the river , which cost 2.3 billion USD, renovated 30 "hot spots" across the Netherlands.

Model of a project of the Room for River project, in which people dug a canal parallel to the river, turned the land into an island - (Photo: roomforriver).

There are many solutions in the Take-a-Water Program and experts will flexibly use which solution for each specific location but they all create more space for floodwater to flow quickly to the sea.

These solutions include: dredging the riverbed, dredging the river bank, moving the dyke away from the river bank, opening a parallel river channel, removing water obstacles, increasing or decreasing the height of the dike, reinforcing the dyke , put pump station .

For example, the Bersche Maas River project includes the construction of eight high mound areas, raking 500,000m of soil to reduce the height of 6km of dike on a river bank, dredging 5.5 ha of sand to help reduce the water level here 27cm .

In the city of Nijmegen and Lent, people dug a canal in promontory that jutted into the river, turning this land into an island. In total, 5 million m3 of sand and clay must be dredged and removed to create an additional flow for the Waal River. Results of water level when flooding decreased by 35cm.

Similarly, all other works help the river water level drop from 30-70cm when flooding occurs.