Seventeen years after the Three Gorges Dam was built, 1.8 billion tonnes of sediment has been deposi

Mondo Science Updated on 2024-02-13

The Three Gorges Dam project is one of the most important projects since the founding of the People's Republic of China.

Because when New China was first founded, we faced many problems, such as not having so many water resources for grain irrigation.

For example, the Yangtze River and the Yellow River are likely to be flooded, posing a safety risk to the people living in the surrounding areas, so it is necessary to build large-scale water conservancy projects to regulate water resources.

After this century, China has spent a lot of money and resources to build the Three Gorges Dam.

But now there is a new problem at the Three Gorges Dam, and that is the accumulation of sediment.

First, the problem of sediment accumulation

According to the statistics of the relevant departments, the total amount of sediment that has accumulated at the Three Gorges Dam has reached 1.8 billion tons.

In fact, such a serious accumulation of sediment was completely expected.

After all, the Three Gorges Dam has been built for 17 years, and it is quite normal for only about 100 million tons of sediment to accumulate every year.

However, from a scientific point of view, the large amount of sediment accumulation will also have some adverse effects on the operation of the Three Gorges Dam

The Three Gorges Dam itself is a mega-project to regulate the Yangtze River's water supply and control flooding.

If the waterway of the Three Gorges Dam is deposited with a large amount of sediment, it will have a huge impact on the water storage capacity and water transfer function of the dam itself.

Because the existence of sediment will lead to a decrease in the water volume ratio of the reservoir, then the water volume ratio will decrease, which will directly affect agricultural production.

Moreover, the large amount of sediment will directly affect the quality of the water in the reservoir.

There are some seriously polluted stored water that cannot be used for agricultural irrigation, and can only be used as secondary or ** water sources for industrial use.

The large amount of sediment accumulation itself can raise the riverbed.

The ecological impact of riverbed elevation is enormous, and it also poses a danger to the people living on both sides of the river.

One of the most typical examples is the Yellow River.

Historically, the Yellow River has been diverted many times, and the important reason for the diversion of the Yellow River itself is that the Yellow River is a sediment river.

The Yellow River has a large sediment content, and some of this sediment will accumulate on the riverbed as it drifts down the river, eventually gradually raising the riverbed.

When the riverbed is already higher than the river or embankment on both sides, the embankment will burst.

And now the sediment accumulation rate of the Three Gorges Dam on the Yangtze River is so high, which means that the riverbed is increasing.

If the riverbed is higher than the dam, the dam will also fail, which is too dangerous.

Finally, the accumulation of large amounts of sediment will also directly affect the ecosystem in the reservoir, and some aquatic organisms must be in relatively clear water sources to survive.

Once the sediment becomes more abundant and the water quality is affected, then there is no way for these organisms to continue to survive in the reservoir.

Therefore, the loss of water clarity and water pollution caused by sediment accumulation can destroy the already abundant aquatic biological resources in the reservoir.

Under such circumstances, the problem of 1.8 billion tons of sediment accumulated in the Three Gorges Dam has received great attention.

There are many people who hope that the state can solve the problem as soon as possible.

So, what are the ways we can solve the problem?

Second, when the Three Gorges Dam was built, the problem of sediment accumulation was taken into account

As long as the Three Gorges Dam exists, sooner or later there will be sediment accumulation.

Although the water of the Yangtze River is clearer than that of the Yellow River, and there is not so much sediment, as long as the river is running, it will carry more or less sediment in the process.

Dams around the world are built with sediment in mind, and the Three Gorges Dam is no different.

The Three Gorges Dam has multiple sand outlets, and once the sediment in the reservoir accumulates to a certain limit, which threatens the safety of the dam, these sand outlets will play a role.

Workers at the Three Gorges Dam will open the sand outlets, which can dump some sediment downstream, so that there are few serious environmental accidents.

Although the reservoir on the Three Gorges Dam still needs to discharge sediment downstream, the amount of sediment to be discharged can be strictly controlled through dam regulation.

A small amount of sediment is discharged downstream, which does not accumulate too much on the riverbed and is washed away by the huge current.

Eventually, there is a high risk that the sediment will be washed into the sea, which will not cause the downstream waterways to rise.

Therefore, the state has fully taken these problems into account when building the reservoir, so we don't need to worry too much about the accumulation of sediment in the Three Gorges Reservoir.

Conclusion:

At present, the reservoir officials have not directly discharged sediment downstream, which proves that the sediment stored in the reservoir has not reached the set storage limit.

Once the upper limit is reached, the sand will be unloaded through an opening.

In fact, every year, some sediment will be discharged from the open sand discharge outlet for a short time at a fixed time.

In the past, there was not enough technology to control sediment and there were no perfect water conservancy facilities, but now that there are technologies and facilities, why should we worry about sediment accumulation? Countries that have problems must have already had plans in place to deal with them.

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