The Juyan Flood in East Juyanhai

When the ancestors enjoyed the rich products brought by Juyanhai and were intoxicated by its beautiful natural landscape, they would never have thought that this water town in Zeguo would one day turn into a desert with thousands of miles of red land. And this change has begun inadvertently. Immigrants from the Western Han Dynasty reclaimed wasteland, oases were developed, and surface vegetation was destroyed, burying the hidden worry of land desertification. Farming in the Tang Dynasty created the glory of "no wealth in the world can come from Longyou", but also gradually caused the ecology of the Heihe River Basin to lose balance. After more than 1,000 years of extensive reclamation and the destruction of water sources by wars in the late Yuan and early Ming dynasties, the ancient Juyan-Heicheng area became desertified land. The once prosperous Heicheng oasis civilization came to an end in the 14th century. Now there is only a dead city left, like a mummy that has lost its soul and moisture, standing in the depths of the desert, blown by the strong wind and sculpted by quicksand.

Despite the impact and destruction of human activities, until the early 1950s, there were still large deltas with fertile water and grass in the lower reaches of the Heihe River. The East and West Juyan Seas also maintained 35 square kilometers and 267 square kilometers respectively. Square kilometers of larger water surface. After the founding of the People's Republic of China, with the growth of population and development of productivity, the influence on Juyan area increased rapidly. From the 1960s to the 1970s, the military and civilians cleared wasteland for farming, cut down a large number of trees and built air defense projects, causing serious damage to forest and grass vegetation. In the early 1990s, the trend of indiscriminate mining of licorice, cistanche and other Chinese herbal medicines, as well as overloading and overgrazing of pastures, intensified the trend of desertification in oasis. The intensification of human impact on natural ecology is particularly prominent in the middle reaches of the Heihe River. In the Han Dynasty, the middle reaches of the Heihe River had a population of only 80,000 to 90,000 people and an irrigated land area of ??about 70,000 acres. In the early days of the founding of New China, the population was about 550,000 and the irrigated area was 1.03 million acres. Now it has a population of 1.21 million and an irrigated area of ??3.34 million acres. Ten thousand acres, showing a geometric growth trend. In order to support agricultural production, the middle reaches of the Heihe River have accelerated the pace of water conservancy project construction and development. By 1999, 58 medium and small reservoirs had been built in the Heihe River Basin, including 40 plain reservoirs with serious evaporation and leakage losses, with a total storage capacity of 255 million cubic meters. There are 66 fixed diversion canals with a water diversion capacity of 268 cubic meters per second, and 19 irrigation areas of more than 10,000 acres. The water diversion capacity of the midstream has been greatly improved, and water consumption has increased, causing the amount of water entering the downstream to decrease year by year. According to hydrological data statistics, the runoff of Langxin Mountain in the 1950s was 820 million cubic meters, and in the 1990s it dropped to 347 million cubic meters, a decrease of 473 million cubic meters, a decrease of 57.7%. Reservoirs were successively built on the tributaries of the Heihe River to retain water, causing some larger tributaries to gradually lose contact with the main stream.

The journey of the Heihe River towards the Juyan Sea has become increasingly heavy and difficult. The downstream drying time gradually extended from about 100 days in the 1950s to nearly 200 days in the late 1990s. . In 1961, the West Juyan Sea dried up, and in 1992, the East Juyan Sea disappeared. The Pearl of the Desert has lost the last ray of luster in its life, and Juyanhai has become the second largest dry lake in western my country after Lop Nur.

The demise of Juyanhai is by no means as simple as the loss of a sea for people to watch and chant. It is a starting point for the accelerated reversal of Ejina Oasis towards desertification and the overall deterioration of the ecosystem in the lower reaches of the Heihe River. of a sign. What it brings is a heavy ecological disaster. According to the 2002 census data, there are 1.76 million acres of Populus euphratica, Elaeagnus euphratica and tamarisk in the East and West River Basins of Ejina, which has decreased by 1.59 million acres or 47.5% in the past 40 years. According to satellite image data, from the 1980s to 1994, the area of ??forest land with vegetation coverage greater than 70% in the lower delta region decreased by 2.88 million acres. Since the 1980s, forests, shrubs, meadows and grasslands with vegetation coverage greater than 70% have decreased by approximately 78%. The number of herbaceous plants in the oasis has decreased from more than 200 species in the 1950s to more than 80 species. The shrinking of oasis and the degradation of vegetation have caused the rare animals in the area to lose their habitats. Of the original 26 species of nationally protected animals, 9 species have disappeared and more than 10 species have migrated to other places. The touching scene of the past of "beating yellow sheep with sticks and scooping out fish, and pheasants falling in the yard" has become a distant memory.

"Ejina Banner Chronicles" records that there were originally 14 large and small lakes, 16 springs, and 4 swamps in the Juyan area. Due to the reduction in water discharge from the Heihe River, they all disappeared by 1992. From the 1960s to the present, it is estimated that approximately 3.78 million acres of water areas and wetlands have disappeared. From the 1960s to the 1980s, the Gobi and desert areas with vegetation coverage of less than 10% in Ejina Banner increased at an average rate of 23.1 square kilometers per year. Today, the east, south and northeast of Dalaikubu Town, the center of the downstream oasis, are surrounded by a crescent-shaped sand dune chain. The newly formed desert is connected with the Badain Jaran Desert and continues to advance towards the oasis. According to statistics, the oasis area has dropped sharply from 6,900 square kilometers in the 1980s to more than 3,000 square kilometers currently. The ebb and flow of wetlands and deserts has led to climate deterioration. Since the late 1980s, the average annual precipitation in the Juyan Oasis area has decreased by 31.3 mm compared with the 1950s, a decrease of nearly 60%. Especially after the Dongjuyan Sea dried up, sand and dust raged every spring, causing the oasis to lose its grass and trees and become a depressed scene. This is a depressing set of data and clear evidence of the ecological deterioration of the oasis.

The drying up of the Juyan Sea and the continuous shrinking of the Heihe River have brought the threat of sand to the city, and the life of the Ejina Oasis hangs on the water.

In the mid-1990s, two professors from Peking University, Chen Changdu and Cui Haiting, classified the Juyan area as an "ecological crisis area", an area that would become ecologically unrecoverable if no rescue was done. What is even more worrying is that the ecological consequences of the drying up of the Juyan Sea are not limited to the Ejina Oasis. In May 1993, a huge sandstorm occurred in northwest my country, and the Alxa area was one of the important sand sources. In this disaster, 5.6 million acres of crops were affected, 85 people died, some roads, railway transportation and power supply lines were interrupted, and economic losses reached 550 million yuan. In early 2000, northern my country was hit by large-scale sandstorms eight times in a row, affecting a land area of ??2 million square kilometers. In May of that year, CCTV's "News Investigation" column broadcast the feature film "Shaqi Ejina", pointing out that sandstorms in the direction of Ejina are one of the main sources affecting the weather in the Beijing area, which aroused strong reactions from all walks of life. The Juyan area has become a major source of ecological deterioration in China. typical.

It is not difficult to speculate: If Juyanhai disappears for a long time, this area will gradually become my country's second Lop Nur. An important "bone" will be removed from the "Three North" protective forest system, which will not only cause the northwest The regional ecology has seriously deteriorated, and the Hexi Corridor will also lose its northern barrier and military support; if the Juyan Sea disappears for a long time, the Juyan Oasis will continue to shrink, and the Mongolian Torghut tribe will return to their motherland at the cost of their blood and lives. Descendants will have to travel far away again, and oasis civilizations such as Juyan and Heicheng will sleep forever under the long yellow sand and will never see the light of day again. It can be said that restoring the vitality of Juyanhai is directly related to national unity and national defense stability, to the implementation of the Western Development Strategy, and to the ecological protection and improvement of northwest and north China.