It can be said that the experts and scholars on the scene were basically at a loss to solve this problem, and Zhao Yi did not figure out how to solve this problem for a while.
He paid little attention to this in his previous life, and at such a meeting, he did not have enough basic data on hand to make a relatively accurate judgment.
The leader saw that the scene was silent for a long time, and no expert spoke, so he coughed and said: "This issue is only for discussion, and it is not meant to be implemented immediately. All possible solutions can be discussed."
Hearing the leader's words, the atmosphere at the scene suddenly became better. There were many experts on the scene with wild ideas. Regardless of whether they were useful or not, it was always good to use as a reference item.
For example, one expert said: "In fact, according to satellite cloud images, a large amount of high-altitude water vapor enters our country from the south, west and north of Xinjiang every year. The annual water vapor volume reaches more than 1.8 trillion tons, and occasionally exceeds 2 trillion tons. Ton.
It's just that this water vapor is running at high altitudes in the middle and upper troposphere above 2,000 meters above sea level and in the lower stratosphere at 16,000 meters above sea level.
Although the Pamir Plateau in southwestern Xinjiang and the Tianshan Mountains in western and central Xinjiang will block part of the water vapor entering from the western border and form alpine rain and snow, most of the water vapor can still drift through these mountains and over Lop Nur.
However, this water vapor has been drifting at high altitudes and is difficult to form effective rainfall. In winter, it directly enters the Aleutian low-pressure area of the Pacific Ocean or enters the equatorial region with the monsoon.
In summer, the monsoon from the southeast and southwest converges with the middle and lower reaches of the Yangtze River, the Sichuan Basin, the east of the Loess Plateau, North China, and Northeast China, producing a large amount of rainfall.
In fact, most of this water vapor still enters the Aleutian low pressure area northeastward, and the other part is swept into the trade wind area by the subtropical high pressure.
On average, the total amount of water vapor entering Xinjiang every year exceeds 1.8 trillion tons, mainly flowing in from the western border and flowing out concentratedly from the eastern border. The water vapor left in Xinjiang every year is only more than 50 billion tons, which is less than 1.8 trillion tons of the total water vapor entering Xinjiang. 2.9%.
Therefore, if this high-altitude water vapor can be effectively utilized, the water shortage problem in the northwest will be completely solved, and the northwest can also return to the fortress of Jiangnan during the ancient Dayu period. "
If the data mentioned by this expert are relatively accurate, with such a huge amount of high-altitude water vapor flowing into our country every year, it is indeed necessary to find ways to utilize this part of the water vapor.
Not to mention all utilization, only a part of the total amount of water vapor needs to be utilized, which is of great value. At least the ecology of the area east of Lop Nur will be greatly changed.
It's just that the idea is good, but it's extremely difficult to implement. This is why the expert didn't mention it at all before, because he felt that it would have no effect if he mentioned it.
After the expert finished speaking, another expert asked: "If this water vapor is allowed to form rainfall, will it have an impact on the current ecosystem? Is there any assessment in this regard?"
After hearing this, the expert who just spoke said: "It will definitely have an impact on the current ecological system, but I think it will be a good impact, not a bad impact.
The reason why we want to solve the water shortage problem in the northwest is to solve the ecological deterioration problem there. Although the ecology has been greatly improved in recent years due to the outstanding performance of Yaoguang Environmental Management Company.
However, this improvement has not resulted in a fundamental reversal. In other words, although the performance of Yaoguang Environmental Management Company looks good, it will naturally deteriorate in the future.
I have a data here. In the early 1970s, with the complete drying up of Lop Nur, in just 10 years, the Badain Jaran Desert, which was at the critical point of desert growth, increased by 50%, the Tengger Desert increased by 10%, and the Ulan Desert increased by 10%. Buhe Desert increased by 20%.
And it was also in 1972 when Lop Nur completely dried up that the Yellow River Basin began to dry up, and it became more and more serious. If not taken seriously, the water shortage problem in the Yellow River Basin will become more and more serious. "
When the leader heard this, he turned to Zhao Yi and said, "Can you tell us specifically about the transformation of the Tengger Desert, Badain Jaran Desert and Ulan Buh Desert and the difficulties they face?"
The experts on site did not necessarily know who owned Yaoguang Environmental Management Company or who the operating companies in these places belonged to, but the leaders knew very well, so they asked Zhao Yi.
Hearing the leader ask him, Zhao Yi sorted out his thoughts and said: "The reason why Yaoguang Environmental Management Company only transforms these deserts and desertified land is because these areas have certain transformation conditions.
I won’t go into detail about the Mu Us Sandy Land. It is only because the vegetation was severely destroyed before that desertification occurred. Therefore, it is the most suitable for transformation and the cost of transformation is also the lowest.
Judging from the current operating conditions of Tianji Agriculture and Animal Husbandry Company, as long as there is a plan and no excessive grazing, there is basically no possibility of Mu Us Pasture being degraded into sandy land.
Of course, in order to prevent wind and sand from eroding the Mu Us Ranch, the Yaoguang Environmental Management Company transformed the Tengger Desert. The improvement of the environment of the Mu Us Ranch has also led to an increase in rainfall in these areas, which has contributed to the transformation of the Tengger Desert. Certain conditions were created.
Moreover, the Tengger Desert itself also has some water reserves, but compared to the entire desert, they are a drop in the bucket. When the Fluolight Environmental Management Company originally renovated, they used water resources with high drought tolerance, low evaporation and high water vapor adsorption capacity. Loam grass.
If we follow conventional management methods, it is basically impossible to change the Tengger Desert into a grassland pasture. Moreover, after the Tengger Desert is transformed into a pasture, there is a possibility that it will continue to be eroded.
That’s why there were plans to transform deserts on the edge of the Tengger Ranch such as the Badain Jaran Desert and the Ulanbur Desert. The current results can only be said to be average.
In order to solve the problem of vegetation survival in these deserts, we adopted intelligent drip irrigation technology in the early stage, and later adopted anti-evaporation unidirectional film technology, which basically achieved the conditions for effective retention of surface water.
The overall plan is to proceed step by step from east to west, starting with the easier and then the more difficult. As the environment gradually improves, the rainfall in these areas is also gradually increasing. However, if we want to form a complete internal circulation of Jiangnan, we do not yet have the conditions. .
In other words, if there is no manual maintenance, it may still be slowly eroded by the wind from the west, causing the Badain Jaran Desert to degrade.
At present, the Fluolight Environmental Management Company still needs to dispatch a large number of staff to perform manual maintenance on the outer edge areas of Badain Jaran and Ulan Bhe Desert every year, and the annual maintenance costs are quite high.
From these aspects, Yaoguang Environmental Management Company has indeed achieved fruitful results in environmental transformation in the northwest, but it has not achieved fundamental changes in the climate conditions of the northwest.
Therefore, if we want to change the overall environment of the Northwest and form a self-circulating and sustainable environmental and ecological construction, we must further improve the problem of water shortage in the Northwest.
In fact, I think there is no need to consider the impact of the increase in water resources on the climate of the Northwest. The current environment in the Northwest is already very harsh, and it will not get worse than this.
Historically, the location of this 'exposure' in ancient times was very different from today. In ancient times, there were four major lakes: Lop Nur, Aydin Lake, Hami Basin, and Qaidam Basin, which we call the 'Lop Nur Lake Group'.
Now these lakes have dried up, and the ecological environment in the Northwest is deteriorating, which is closely related to the shrinking of these lakes.
Therefore, I believe that only by truly restoring the ecology of these places can we truly change the environmental conditions of the Northwest. Otherwise, it will be difficult to achieve stable and sustained environmental transformation results. "
To be honest, if it were not for the protection of Mu Us Ranch, there would not be a project to transform the Tengger Desert. After all, compared to Mu Us Ranch, the environment of the Tengger Desert is much harsher.
In order to protect the Tengger Ranch, it is necessary to transform the Badain Jaran Desert and the Ulan Buh Desert. In order to maintain the current transformation results, the annual maintenance cost is very large.
Therefore, for Zhao Yi, he hopes most to change the environment in the northwest region. If a stable and good environment is formed, the annual maintenance costs will be much less, and the carrying capacity of these transformed lands will be stronger.
At this point, Zhao asked the expert who just proposed the utilization of high-altitude water vapor: "Is it necessary to fill the dry lakes in the northwest with water to form low-altitude water vapor, and let these low-altitude water vapor and high-altitude water vapor converge to guide more Water vapor at high altitudes causes rainfall?”
After hearing this, the expert nodded and said: "It is indeed the case. As long as the water system in these places can be restored, effective low-altitude water vapor can be formed and converge with high-altitude water vapor, which will play a huge role in promoting the formation of rainfall by high-altitude water vapor." effect."
"It can be seen from your description that just by injecting a large amount of water into Lop Nur, a low-altitude water vapor environment can be formed in the area, allowing a large amount of natural rainfall to occur in the Lop Nur area and the Heihe River Basin and Shiyang River Basin in the downwind area.
Therefore, the environmental transformation in the northwest mainly focuses on transforming the environment of Lop Nur and restoring it to at least the 16,000 square kilometers of water surface during the Qin and Han Dynasties, and preferably to the 26,000 square kilometers of water surface area during the Dayu period 4,000 years ago.
Am I right to understand this? "Zhao Yi continued to ask.
"It can be understood that Lop Nur is a concentrated exposure of high-altitude water vapor from Xinjiang to the northwest region. Restoring the environment of Lop Nur is the most cost-effective solution to change the ecology of the northwest region, and it is also a problem that must be solved.
However, it is best to restore the water systems in the western part of the Hami Basin, Aydin Lake, and Qaidam Basin. The effect will be the best, but the difficulty will also be the greatest. ” said the expert.
"Then have you ever thought about how much water needs to be replenished every year? How many years does it take to recover?" Zhao Yi asked.
Seeing Zhao Yi's detailed question, the leader seemed to be very interested in this proposal. Since he asked this, it might be possible to implement it, so the leader also watched the changes and listened silently to their discussion.
“There are no specific calculations on this yet. After all, this is also a preliminary idea, and the possibility of restoring the Lop Nur water system has not been considered at all before.
However, I think that at least 100 billion cubic meters of water need to be transferred every year to achieve an initial and slow change in the Lop Nur water system, and then change the environment in the northwest Hetao area.
If we calculate based on annual input of 100 billion cubic meters and annual evaporation of 16 billion cubic meters, it will take nearly 40 years to reach the initial water area of 16,000 square kilometers.
If we want to achieve the effect of Dayu's flood control 4,000 years ago, and the area of Lop Nur reaches 26,000 square kilometers, the time required will be about 160 years.
However, this does not take into account the convergent rainfall formed by low-altitude water vapor and high-altitude water vapor. If this is included in the calculation, the time will be advanced. ” said the expert.
"Is there a model to calculate the amount of high-altitude water vapor rainfall induced by evaporated low-altitude water vapor?" Zhao Yi asked.
"We can only estimate this ratio based on historical environmental conditions. During Dayu's flood control period, the Northwest, from Lop Nur to the Hexi Corridor and all the way to the Yellow River Basin, was full of forests, grasslands and lakes.
Let's take a grassland climate with less water demand as an example. To form a grassland, rainfall must reach 200-400 mm. We take the median value of 300 mm to estimate.
The income scope of the downwind area of the Lop Nur lake group is divided into seven areas: the Qaidam inner river basin, the inner river basin east of Lop Nur, the inner river basin of the Tuha Basin, the inner river basins of the Heihe and Shiyang Rivers, the Yellow River basin, the Qinghai-Tibet Plateau and other areas.
The respective estimates are as follows:
The average length of the Qaidam River Basin is 580 kilometers, the average width is 300 kilometers, and the area is about 174,000 square kilometers. The current average rainfall is about 80 millimeters. It has returned to the grassland average rainfall of 300 millimeters, and the rainfall has increased by 200 millimeters, leaving 174,000 square kilometers. New rainfall amounted to 38.28 billion cubic meters.
Calculated in this way, Lop Nur and the inland river basin to its east have received an additional 47.04 billion cubic meters of rainfall. In the river basins of the Tuha Basin, 33.6 billion cubic meters of new rainfall were added, and in the middle and upper reaches of the Yellow River, 30 billion cubic meters of new rainfall was recorded.
The Qinghai-Tibet Plateau, including the Qiangtang Plateau and the Yangtze River source area, is expected to receive approximately 15 billion cubic meters of additional rainfall, which will play a huge role in restoring the shrinking water sources in the Yangtze River source area and suppressing the declining lake levels in the Qiangtang Plateau.
Other areas, including the Tarim Basin in the west of Lop Nur, the northern part of the eastern Tianshan Mountains, northern Xinjiang, Mongolia and other areas, are predicted to increase rainfall by about 18 billion cubic meters.
The above total increased rainfall is 250.32 billion cubic meters. This is the most conservative calculation method, which is equivalent to transferring 100 billion cubic meters of water to the surrounding Lop Nur for irrigation.
In order to prevent the irrigated land from being salinized, 30% of the irrigation tailwater, 3 billion cubic meters, was retained and flowed into Lop Nur Weilu Lake to collect salt and restore the Lop Nur Lake water area of 26,000 square kilometers.
The evaporated local water vapor will increase precipitation by 250.32 billion cubic meters. The increased rainfall is 2.5 times the 100 billion cubic meters of water diversion. In other words, the utilization efficiency of water diversion increases by 2.5 times.
It also adds appropriate surface water and river runoff to the mountainous areas in these areas, naturally restores many large and small lakes such as Juyanhai, Qingtu Lake, and Jilantai, and ensures the restoration of water and soil ecology in Qinghai Lake, Qiangtang Plateau, and Sanjiangyuan. and stable water source foundation.
With the improvement of humidity and climate in the northwest, many large and small lakes have naturally recovered, accompanied by various air currents such as westerly winds, northwest winds, southwest monsoons, and southeast monsoons.
Once again converging with evaporated water vapor, it will also bring a certain amount of rain and snow to North China and central and eastern Inner Mongolia, playing a positive role in increasing humidity and rainfall in the entire northern region.
The rainfall brought by the restoration of the Lop Nur lake group can also be verified by the shrinkage of Qinghai Lake.
According to the ancient lake embankment ruins and Chahan City ruins built on the shores of Qinghai Lake in the Han Dynasty, it can be determined that the area of Qinghai Lake in the Han Dynasty was about 7,000 square kilometers, which was 2,500 square kilometers larger than now.
It can be estimated that the rainfall in the Qinghai Lake Basin before the Han Dynasty was at least 100 mm more than it is now, otherwise such a large lake area could not be maintained.
The ability of Qinghai Lake to maintain its current water area mainly depends on the rainfall brought by the southwest monsoon and southeast monsoon.
Similar verification can also be carried out from many aspects.
For example, Qingtu Lake in Minqin, Gansu Province was called Baitinghai and Xiutuze in ancient times, and dating back to before the Eastern Zhou Dynasty, it was called Zunyeze.
Zunyeze covers an area of 8,000 square kilometers, and the downstream Jilantai Lake covers an area of 3,500 square kilometers, and finally flows into the Yellow River.
Here we can make a simple estimate: the two lakes combined cover an area of 11,500 square kilometers. Based on the current actual evaporation of Bosten Lake of 1,100 millimeters, the evaporation alone has reached 12.65 billion tons, and there is also runoff that overflows into the Yellow River.
It can be seen that how much water was produced in the Shiyang River Basin during Dayu's flood control period 4,200 years ago? At least 10 times the current water production of 1.6 billion cubic meters! .
At that time, the Shiyang River Basin, including the ancient Yellow River route from the west of Helan Mountain and the east of Yabulai Mountain to Bayannur, including the current Tengger Desert and Ulan Buh Desert, was in a good vegetation state with runoff. .
From this perspective, it also shows that the rainfall in the downwind area of Lop Nur changes with the size of the water area of the Lop Nur lake group.
(PS: Part of the above content is excerpted from Mr. Yulushui’s "Asking Water in the Northwest".)" said the expert.
Zhao Yi did not expect that the data collected by this expert was so detailed. Originally, he just wanted to hear a rough figure. It was very difficult to make detailed calculations.
Using ancient rainfall as a reference value for the effect is a very good calculation method, and based on the lowest standard, there is 2.5 times the rainfall. In fact, it must be much higher than this value.
The reason why Zhao Yi is so interested is because he wants to transfer water from the Bohai Bay to Lop Nur. The surface distance between the two is about 2,300 kilometers, and the maximum lift will not exceed 1,000 meters. It is still highly executable.
As mentioned before, raising a ton of water by one meter consumes 0.00272 kilowatt-hours of electricity. If calculated based on the effective power of 0.8, raising a ton of water to a height of 1,000 meters only consumes 3.4 kilowatt-hours of electricity.
If calculated based on 100 billion cubic meters per year, the annual electricity consumption will exceed 340 billion kilowatt-hours. Calculated based on the electricity price of 0.1 yuan per kilowatt-hour after the completion of the photovoltaic power plant in the future, the transportation cost alone will consume 34 billion yuan per year.
If the desalination cost of 0.1 yuan per ton is added, the annual capital consumption increases to 44 billion yuan. If the depreciation cost of building pipelines is added, the annual capital consumption does not exceed 50 billion yuan.
If the ecological system of Lop Nur is initially improved, it will take about 40 years, which means that the total scale of investment will reach 2 trillion yuan.
Although the overall investment scale is very large and will continue to operate for a long time in the future, Zhao Yi feels that it is still a worthy investment project, but how to invest needs to be discussed carefully. (End of chapter)