How did the Three Gorges intercept the flow, and was it all blocked?

No drains were left to generate electricity and locks were set up.

According to the diversion nullah interception construction plan recently agreed by the hub engineering group of the Acceptance Committee of the Second Phase of the Three Gorges Project of the Yangtze River, the construction method of "double-sided two-way (one-way downstream) vertical blocking and interception" will be adopted for this interception.

The "戗" here refers to the interception of the cofferdam and the embankment. The diversion nullah adopts double interception, which means that there are two cofferdams upstream and downstream to intercept the flow at the same time; "Standing blockage" is a kind of interception method, and its construction method is to use dump vehicles to continuously throw stones into the river to form an embankment, and gradually narrow the river width until the Longkou is cut off to complete the closure; "Two-way" means that both sides of the river are thrown at the same time, and the last two cofferdams are closed; "One-way" means that a cofferdam is thrown forward in one direction from one shore to the other.

Because the diversion nullah is the only channel at the Three Gorges dam site after the Three Gorges River is intercepted, its width is only 350 meters, and it is artificially excavated, its bottom is not as rough and bumpy as the natural riverbed, and most of it is smooth concrete floor. The narrow river channel, high flow velocity, large drop and interception projectiles are easy to be washed away by water, which greatly increases the difficulty of intercepting the open channel.

In order to reduce the difficulty of interception and ensure that the dragon is closed in one fell swoop, the diversion nullah interception construction adopts a three-step approach.

First of all, the problem of smooth bottom of the open channel and the difficulty of the projectile to stand is solved. Since the end of September this year, the diversion nullah interception construction started, and the interception construction unit threw more than 1,300 steel frame gabions and alloy mesh stone pockets at the bottom of the diversion nullah, forming a stone barrier near the interception cofferdam, making the bottom of the diversion nullah rough and bumpy, and laying the foundation for reducing the flow loss when intercepting.

The second stage is to intercept the flow of cofferdams and embankments. According to the interception plan, the formal occupation of the interception cofferdam should be carried out on November 1, and the construction unit has begun to throw and fill the interception cofferdam since mid-October. As of October 25, the upstream and downstream cofferdams have been more than 180 meters away, and the upstream and downstream cofferdams have formed 150 meters and 140 meters wide dragon mouths respectively, only one step away.

The most arduous and challenging step in the interception of the diversion nullah is the closing of the dragon's mouth. According to the interception design, the interception flow rate of the diversion open channel is 10,000 cubic meters per second, the drop is meters per second, the maximum average flow velocity of the upstream Longkou is meters per second, and the maximum average flow velocity of the downstream Longkou is meters per second. These indicators reflect the difficulty of interception of the flow of the river is greater than that of the Three Gorges River.

After the formation of the Longkou, the interception army will carry out high-intensity throwing on the Longkou in 3 to 5 days according to the hydrological situation, including the use of concrete strings with a single weight of about 30 tons and extra-large stones to achieve rapid closing.

The diversion nullah sits on the south bank of the Yangtze River on one side and an almost upright concrete wall connected to the Three Gorges II dam on the other. It is similar to an "isolated island", and there is no land transportation, so the diversion nullah can only rely on throwing from the south bank of the Yangtze River to the nullah, and the interception of the dragon mouth has to be forced to be placed on the right side of the concrete vertical wall, which will make it more difficult to close the dragon.

When the flow is started, the water on the right bank of the Yangtze River is enclosed, the canal is built, and the permanent lock and temporary lock are built on the left bank of the Yangtze River. After the construction is completed, the final interception will begin, the cofferdam of the main channel of the Yangtze River will be removed, and a cofferdam will be built on the right bank of the Yangtze River. The power dam was built in the cofferdam on the right bank, and after all the construction was completed, the cofferdam was dismantled, so that the Three Gorges Hydropower Station was completed.

In the first phase, the right bank of the water area was enclosed and a canal was built, while permanent and temporary locks were built on the left bank. The temporary lock was built and the second phase of interception began. First, the right cofferdam was removed so that the river could pass through, and then the main channel of the Yangtze River was cut off, and the left bank power generation dam section and the middle discharge dam section were dug up.

After the completion of the project, it will enter the third phase of interception. The cofferdam of the main channel was removed and the right bank was fenced off again. After the construction of the right bank power generation dam section in the cofferdam is completed, the cofferdam will be dismantled, and the Three Gorges Hydropower Station will be completed.

Before the Three Gorges Dam was intercepted, a diversion channel was dug next to the dam to divert river water around the dam. In this way, the flow can be intercepted.

The specific process is to fill in the first phase of the earth and rock cofferdam, enclose the Zhongbao Island and the right bank of the back river, form the first phase of the foundation pit, drain the water, excavate to the fresh granite, build a concrete diversion channel channel, and the Yangtze River water flow and passing ships still pass through the main channel of the Yangtze River. After the completion of the diversion channel channel and the temporary lock on the left bank, the first phase of the earth-rock cofferdam was dismantled, and the first interception of the Three Gorges Project - the Dajiang River was carried out.

On November 8, 1997, the successful completion of the Yangtze River interception marked the completion of the first phase of the project and the beginning of the second phase of the project.

From 1998 to 2003, the second phase of the project stage, the main tasks are: to complete the filling of the upper and lower reaches of the second phase of the earth and rock cofferdam in a dry period, and to drain the water in the foundation pit of the river enclosed by the cofferdam.

After excavating to fresh rock, the flood discharge of the concrete gravity dam, the left bank power plant, the vertical ship lift, the left bank non-overflow dam and other dam sections were poured, the hydropower plant was poured, the first batch of hydro turbine generators were installed, and the permanent lock on the left bank was built.

The Yangtze River flows through the diversion nullah, and passing ships sail through the diversion nullah or temporary locks. On November 6, 2002, the second interception of the Three Gorges Project, the diversion nullah, was carried out.

After the interception is successful, the RCC cofferdam is repaired to an elevation of 140 meters in the diversion nullah, and the Yangtze River water is vented from the 22 diversion bottom holes at the bottom of the flood discharge dam section, and the ship passes through the temporary lock. On June 1, 2003, the Three Gorges Reservoir began to store water, and in mid-June 2003, the water was impounded to 135 meters, the permanent lock began to be opened to navigation, and in October 2003, the first units began to generate electricity.

Now dig a tributary next to the place where it is to be intercepted, and when the volume of water in the main stream drops to a certain level, the flow can be intercepted.

First of all, pull the soil and keep pouring soil and stones into the middle of the river, carry out this work on both sides of the river at the same time, until the flow is intercepted, dig out two guide flow channels on both sides of the upstream of the barrage civil engineering, and the flow canal must meet the water flow of the river, so that it will not destroy the barrage civil construction, and the barrage civil construction must pave the way for the dam!

Before the Shanxia Dam was intercepted, a diversion channel was dug next to the dam to divert the river water around the dam. In this way, the stream can be connected.

Now next to the open shunt, and then intercept the flow. This one has a related introduction.

Rivers have dry periods in winter, with small currents and slow flow rates, which are relatively easy to intercept.

1. Intercept the flow during the dry season in winter, intercept half of the flow first, and the river water can flow down normally from the other half of the river.

2.After half of the construction is completed, the other half is intercepted.

3.Complete the Closing Dragon.

Hello, I hope my grandson can help you, I wish you a happy life! First of all, the situation of the Three Gorges Dam is indeed as you said, and at the same time, it is sparse and blocked. The Three Gorges Reservoir has played an important role in flood control, according to the instructions of the Yangtze River Commission of the Ministry of Water Resources, the Three Gorges Minkaijian Reservoir has recently lowered the flood discharge volume five times in a row, and the outflow has been reduced from 35,000 cubic meters per second to 19,000 cubic meters per second now, a reduction of nearly 5 percent, so as to intercept more water from the upstream in the Three Gorges Reservoir area, which has also effectively reduced the water level of the main stream in the middle and lower reaches of the Yangtze River, and eased the flood control pressure in the middle and lower reaches of the Yangtze River.

However, no matter how great the Three Gorges Reservoir is to regulate it, after all, the dam is located in Sandouping Town, Yichang, Hubei Province, strictly speaking, it is in the transition zone from the upper reaches of the Yangtze River to the middle reaches, so it is impossible to cope with the continuous heavy rainfall in the middle and lower reaches of the Yangtze River, especially in the Poyang Lake basin basin, the development of the Poyang Lake water system itself, and the low-lying impulse of the ground bridge in the lake basin area, the narrow flood outlet (about 900 meters) and the communication with the Yangtze River through the lake mouth, the outflow is far less than the speed of rainwater collection of the major tributaries, so there is an emergency in the whole line of the hydrological stations of Poyang Lake. After all, the flood control capacity of the Three Gorges Reservoir is only 100 million cubic meters, compared with the average annual runoff of the Yangtze River of 960 billion cubic meters, which can only be said to be "powerless", which requires scientific scheduling. How to scientifically dispatch and minimize the flood control pressure in the downstream areas of the dam?

Because the rainfall changes every moment or every day, different areas are not the same, there is intermittent, which needs to be based on the upstream inflow flow, downstream river sections and lake water level comprehensive consideration, the general principle is that the flood peak comes to close the gate to block the water in the reservoir area, and the flood peak is gone to quickly take the time to open the gate and release water. If the Three Gorges is only blocked but not dredged, according to the average of 35,000 cubic meters per second, the amount of water flowing into the Three Gorges Reservoir every day will reach 24 * 60 * 60 * 35,000 = 100 million cubic meters, that is to say, it only takes one week to fill the Three Gorges Reservoir, if it cannot be vacated in time, wait until the next flood peak arrives or when the upstream rainfall continues to strengthen when the inflow is much greater than 35,000 cubic meters per second (the maximum inflow can reach 50,000 cubic meters per second), At that time, the Three Gorges Reservoir will no longer have an effective storage capacity to weaken the flood peak, and it will be too late to open the flood gates at this time.

There is less water in the dry water and it is easy to intercept the flow. Eliminate branches.

Generally speaking, the interception time of hydropower projects should be selected in the dry season when the flow rate and drop are small, which can reduce the difficulty of interception. According to hydrological data, the driest flow of the Yangtze River at the Three Gorges Dam site is generally from late January to late February, and the flow rate between the two rivers during this period is generally only 3,000 cubic to 6,000 cubic meters per second.

The flow rate is small, and the construction difficulty is low!

Summary. The Three Gorges Dam is to "block water" and divert water from the south to the north to "sparse" and "store" to turn flooding into water conservancy.

The Three Gorges Dam is to "block water" and divert water from the south to the north to "sparse" and "store" to turn flooding into water conservancy.

Dear, the Three Gorges Dam is generally used to store water from the upstream, and the water of the Huangpu River and the Yangtze River will not flood here during the flood period. Because there are not many tributaries in this Shenkuan area, there is only one tributary, and the basin is not large. The confluence of the Huangpu River and the Yangtze River is as wide as ten kilometers wide, and it is not far from the mouth of the sea.

Looking at the landforms along the Yangtze River, we should be aware that in the three major basins of the middle and lower reaches of the Yangtze River, flood prevention should not be blindly emphasized, but floodwaters should be used to benefit people's lives. Based on the above information, the Three Gorges Dam is dredging rather than blocking.

Therefore, a flood dam should be built at the mouth of Dongting Lake and Poyang Lake, and the lake area should be returned to the lake, so that the two lakes can truly form the lungs of the Yangtze River, or natural reservoirs. In the three major basins, a large area of water may be formed in the local cover, or a single retreat polder embankment may be built. Due to the fact that the scope of the rainfall area cannot be built in advance, the flood storage area can only be built in the low-lying basin in advance, and the flood will be stored in the event of a flood.

In addition to the construction of flood storage areas along the Yangtze River, a number of branch lines of the South-to-North Water Diversion Project should be built, as well as the east-to-west water diversion and western water diversion projects. Conveying impounded flood water to places where water is scarce. In other words, the Three Gorges Dam is "blocked," the south-to-north water diversion is "sparse," and "storage" is added to the flood to turn flooding into water conservancy.

Dear, the Three Gorges Dam is generally excavated and milled to store water from the upstream, and the water of the Huangpu River and the Yangtze River will not flood here during the flood period. Because there are not many tributaries in this area, there is only one tributary, and the basin is not large. The confluence of the Huangpu River and the Yangtze River is more than ten kilometers wide, not far from the estuary.

Looking at the landforms along the Yangtze River, we should be aware that in the three major basins of the middle and lower reaches of the Yangtze River, we should not blindly emphasize flood prevention and scatter cherry blossoms, but should use floodwaters to benefit people's lives. Based on the above information, the Three Gorges Dam is a bright cluster blockage.

Therefore, a flood dam should be built at the mouth of Dongting Lake and Poyang Lake, and the lake area should be returned to the lake, so that the two lakes can truly form the lungs of the Yangtze River, or natural reservoirs. In the three major basins, a large area of water may be formed in the local cover, or a single retreat polder embankment may be built. Due to the fact that the scope of the rainfall area cannot be built in advance, the flood storage area can only be built in the low-lying basin in advance, and the flood will be stored in the event of a flood.

In addition to the construction of flood storage areas along the Yangtze River, a number of branch lines of the South-to-North Water Diversion Project should be built, as well as the east-to-west water diversion and western water diversion projects. Conveying impounded flood water to places where water is scarce. In other words, the Three Gorges Dam is "blocked," the south-to-north water diversion is "sparse," and "storage" is added to the flood to turn flooding into water conservancy.