How much water is there in the Three Gorges Reservoir? How many cubic meters of water does the Three Gorges Reservoir contain?

The Three Gorges Reservoir is the most famous hydropower project in China, and its huge construction is shocking. As the largest dam on the Yangtze River, how many cubic meters of water does the Three Gorges Reservoir store? Many curious friends are full of questions.

1. The Three Gorges has a total storage capacity of 39.3 billion cubic meters and a flood control storage capacity of 22.15 billion cubic meters of water.

2. The normal water level is 156 meters in the early stage and 175 meters in the later stage;

3. Reservoir: The total length of the dam is 3035 meters, and the top elevation of the dam is 185 meters;

< p>You may have no idea about these 39.3 billion cubic meters. Let's take a cube to illustrate how big the Three Gorges Dam is. Assume it is 40 billion cubic meters in 393 years.

Four billion cubic meters is the amount of water that a huge cube 10,000 meters long, 10,000 meters wide and 400 meters high can hold.

Similarly, 22.1 billion cubic meters of flood protection is the amount of water that can be contained in a huge cube 10,000 meters long, 10,000 meters wide and 221 meters high.

The weight of 1 cubic meter of water is what we usually call one ton, and 40 billion cubic meters is 40 billion tons.

Currently, the largest animal in the world, the blue whale, weighs 200 tons, which is equivalent to the entire water volume of the Three Gorges Reservoir.

With the weight of 200 million adult blue whales, even if all the Everyone is 100 kilograms fat, and these 40 billion tons of water are heavier than all the people on the earth.

The main data related to storage capacity is the dam top elevation of 185m, and the water storage level is considered to be 175m. The calculated storage capacity is 39.3 billion cubic meters, of which the flood control storage capacity is 22.15 billion cubic meters. The total length of the Three Gorges Dam crest is 3035 meters.

This problem involves two aspects. The first is accurate measurement and modeling. How is it calculated?

1. Calculation method

The storage capacity calculation method is relatively complicated. We can use a simple analogy to illustrate its basic principles. There are roughly two calculation methods.

1) Contour method. (We can jokingly call it the pie method)

See the closed lines in the picture? This is the contour line. The water level of the Three Gorges is 175 meters. We assume that the bottom of the reservoir is 0 meters, so there are 175 contours. Then the height difference between the first outer circle at the top and the second inner circle is 1m. We can assume that the entire water body is a stack of 174 layers of cake, and the height of each layer of cake is 1m. Typically, the first layer of pie is the largest and gradually shrinks at the bottom, like a stack of pies with a top and a bottom.

We can roughly calculate the volume of the highest water = the area of ??the second circle * 1m. By analogy, and then calculating the volume of the second layer of pie, the final accumulation is the storage capacity of the entire Three Gorges. Of course, the amount of water calculated in this way will be slightly less. We can also treat each layer of cake as a trapezoid to calculate the volume.

2) Equal rectangular prism method (we call it the chopstick method)

It is impossible to find such a three-dimensional reservoir map, so we can only use a mountain to look upside down.

The general idea is: We divide the first layer of cake into a 1-meter square grid at a water level of 175 meters (the water surface is flat). Assume that the area of ??this pie is 100 million yuan. Then there are 100 million grids. The water depth corresponding to each grid is between 175m (assuming the lowest water depth is 0m). We can see that if the water depth on the shore is 1m, then the volume of water in this grid = 1m2*1m. The water depth of part of the middle grid is 175m, so the volume = 1m2*175m. We have accumulated a volume of 100 million cubic meters, which is the storage capacity of the Three Gorges.

We can assume that 100 million chopsticks per square meter are inserted in the reservoir. At their top is a water level of 175 meters. They are all flush, just the downward length is different, just hit it to the bottom.

Now everyone has discovered it. Wow, the calculation method is really simple. Can everyone understand?

2. Measurement and modeling

The calculation method is very simple. In fact, it's better to forget it now. Because we don’t need to calculate it ourselves, as long as the measurements are accurate and an accurate three-dimensional model similar to the picture above is established, the software will calculate it for you.

Accurate measurements are therefore very important. A long time ago, measuring was a very hard job. Everyone has to carry various instruments and travel across mountains and rivers to complete the measurement work, so I won’t go into details

At this point, I think everyone is tired of seeing it. So is such a storage capacity calculation necessary? We can dam the water. Why bother measuring storage capacity?

The storage capacity of this reservoir can be used for a variety of purposes. For example, we know that it is going to rain upstream of the reservoir. Meteorological experts calculated that it will rain 2 billion based on the catchment area and the intensity of heavy rain.

Then the dam managers can release water in advance to free up the corresponding storage capacity (the Three Gorges releases water in advance before heavy rains every year). If the current water level is 175, it can be reduced to 165 after calculation.

For example, if I want to lower the water level from 165 to 155, I can calculate the water volume to be 1.5 billion. Then we can calculate what the downstream water level or water flow velocity will be based on the water volume, thereby controlling the flood discharge speed. Notify downstream to prepare.