Like many developing countries, the modernization of China is accompanied by the deterioration of ecology and environment.
"The more complete the life network, the more vital the river is, and the more it can nourish creatures including humans." Lei Guangchun, who founded the Yangtze River Project from 65438 to 0999, never forgot to preach the concept of "River of Life" on various occasions. Many negative examples he cited are the Yangtze River, and positive examples are the Rhine River in Europe, the Mississippi River in the United States and the Murray-Darling River in Australia.
General rules do not hurt, but pain will not work. This famous saying of meridian science of traditional Chinese medicine is fully applicable to the Yangtze River, the largest river in China. The Yangtze River is like a human meridian system. The main stream and tributaries are meridians, and the surrounding lakes are like acupoints. The flowing river water is the vital qi.
Perhaps most people can intuitively detect air pollution or water quality deterioration, but it is often difficult for people to intuitively feel how economic and social activities threaten the ecological and environmental systems that sustain human survival. The wanton destruction of human beings has caused unprecedented damage to the life system of the Yangtze River.
Mother river of all life forms in the basin
"You walk from the snow-capped mountains, the spring tide is your charm, you rush to the East China Sea, and the stormy waves are your spirit ..." From west to east, the ancient Yangtze River has nurtured a great nation: from the plateau to the sea, it has formed a unique and complex ecosystem, which has become the basis for countless lives to survive; From Bashu ancient culture sequence to Oracle Bone Inscriptions in the Yin Ruins of Warring States: from Liangzhu culture to Gulangyu culture, all of them show the glory of the history of civilization in the Yangtze River. Together with the Yellow River, it created a splendid civilization in China, thus enriching the meaning of the origin of world culture.
The Yangtze River passes through the vertical belt of Hengduan Mountain from the snowy plateau and flows through the flood plain and subtropical forest. The biodiversity of the Yangtze River basin ranks first among the seven major basins in China. The biological species in the basin account for more than half of all species in China. It bred Metasequoia glyptostroboides, Davidia involucrata and Cryptomeria fortunei. Giant panda, Chinese sturgeon, golden monkey, Chinese alligator, Zhu? , baiji and other famous rare animals and plants at home and abroad. There are more than 300 species of birds and 200 species of fish in Dongting Lake and Poyang Lake alone. At the same time, the Yangtze River is the link between land and marine ecosystems, connecting the Qinghai-Tibet Plateau and the East China Sea, and has irreplaceable ecological functions. The wetlands of the Yangtze River and the Yangtze River adsorb and degrade wastes and pollution produced by human activities. Without the Yangtze River, the material circulation, water balance and material and energy exchange between land and sea could not be realized.
The annual runoff of the Yangtze River is 960 billion cubic meters, accounting for 40% of China's fresh water resources. Rapidly flowing rivers provide "golden waterways" and abundant raw materials for industrial and agricultural production, and more than 400 million Chinese sons and daughters were born by the river. Aquatic crops such as rice and fish produced in the Yangtze River wetland have nurtured the Chinese nation for thousands of years: China, which only accounts for14 of the country's cultivated land, produces 70% rice, 40% grain and 33% cotton; Its freshwater surface accounts for 1/2 of the whole country, and it produces 60% of freshwater fish in the whole country. The Yangtze River Basin is one of the most economically developed areas in China, with more than 100 large and medium-sized cities and more than 2,000 towns along the line. The whole basin has created 40% of the country's total industrial output value. The Yangtze River Economic Belt runs through the eastern, central and western parts of China, and it is the largest and most influential river basin economic belt in the world. It is the backbone of China's economic development and modernization, and has an irreplaceable strategic position in supporting the sustainable development of China's social economy.
Therefore, "the mother river of all life forms in the basin" is the most accurate and gentle compliment to the Yangtze River.
Mother river is in emergency.
Although the figures are boring, the information contained in them is enough to worry us: glaciers are the cleanest natural fresh water resources in the source area. In the past 30 years, the glaciers in the source area of the Yangtze River have been shrinking. Due to the thinning of the surface and the retreat of the end of the glaciers, the water resources of the glaciers have decreased from 1993 to 1995, a decrease of more than 700 million cubic meters. At the same time, the frozen soil in the source area is deteriorating, swamps and wetlands are shrinking, and lakes are generally shrinking. From Kunlun Mountain to Tuotuo River, a considerable number of grasslands are desertified, vast and desolate.
Land degradation is followed by grassland vegetation degradation. Exposed ground, soil erosion. At present, the loss area of the whole basin is 55 1.80 square kilometers, accounting for 36.2% of the land area of the basin, with an average annual soil erosion of 2.4 billion tons. Every year, millions of hectares of land are degraded and even bare rocks are formed. The riverbed of the Yangtze River rises at the rate of 1 cm every year.
In the early days of People's Republic of China (PRC), most areas of the Yangtze River Basin had good vegetation. However, long-term predatory logging and deforestation have greatly reduced the forest canopy density in the basin. 1994, state-owned forest areas in Sichuan, Yunnan, Shaanxi and Gansu provinces cut forests 178.8 square kilometers. The original vegetation in the Yangtze River basin lost 85%, and the forest coverage rate in the upper reaches dropped to about 10%. Most of the forests that used to absorb a lot of rain in the rainy season no longer exist.
If a river has life, its vitality comes from the unique system formed by the thread communication and free flow between the mainstream and tributaries, lakes and wetlands.
The free communication between rivers and lakes makes the lake area very flexible, which can provide more space for flood storage and drainage and greatly reduce the harm of floods. The natural connection between the lake and the Yangtze River can protect the natural properties of the lake and the stability of the ecosystem, slow down the lake's shrinkage, maintain more types of wetlands such as water-level fluctuation zones, shoals and beaches, which is conducive to the protection and restoration of biodiversity, enhance the ability of the lake to degrade pollution and prevent flood storage, and provide places for migratory or semi-migratory fish to feed, breed and fatten.
From 1950s to 1970s, the rapid increase of population in China led to the continuous shortage of grain and cultivated land, and a large-scale reclamation movement around lakes began. First of all, we must control the water level of the lake, so large and small dams and sluices will separate the lake from the Yangtze River. This movement, which lasted for more than 20 years, made the lakes in the middle and lower reaches of the Yangtze River disappear 1/3 or more. In the early days of the People's Republic of China, there were 1.066 lakes in Jianghan Plain, and Hubei Province was also called "the province of thousands of lakes". However, in recent decades, Hubei Province has only 1 80 lakes with an area of1square kilometer, which is not worthy of the name.
From the "Zhenjiang Tower" built during the Qianlong period to today's Qianli River Defense, the Yangtze River has gradually lost contact with lakes on both sides of the river. A large number of Tongjiang lakes are blocked by facilities such as river banks. The annual discharge of industrial wastewater and urban sewage in the Yangtze River basin exceeds 25 billion tons, accounting for about 58% of the total discharge of industrial and domestic sewage in China. The water environment of closed lakes is deteriorating gradually.
The Yangtze River can only be silent, but silence does not mean obedience. Before the Tang Dynasty, there was an average flood disaster in the Yangtze River basin for about 20 years, and then it gradually increased, once every two years on average since 1980, and sometimes even occurred year after year.
People often think that hydropower projects will not cause pollution, but from the history of dam construction in the world, reservoirs built for power generation may cause serious environmental pollution. After the completion of the dam, the flow rate will decrease, which will lead to the accumulation and precipitation of toxic pollutants such as heavy metals in the reservoir and aggravate the deterioration of water quality.
Building dams and using hydropower will not only create new pollution sources, but also turn some valuable and reusable resources into endangered resources or make them extinct. A newly published international report shows that 2/kloc-0 rivers and their basins have been seriously degraded due to the threat of dam construction to freshwater ecosystems, and the Yangtze River basin in China is unfortunately ranked first.
The unique environment of the fast-flowing Yangtze River has bred nearly 100 kinds of fish with different characteristics. At present, more than 200 dams have been built, under construction and planned on the main stream and tributaries of the Yangtze River, and the special water flow environment of the Yangtze River has disappeared due to the construction of dams. Fish have become the first "victims", especially those migrating from rivers and lakes ―― these fish need to return to specific reaches and lakes in the upper reaches from the lower reaches of the sea or rivers regularly to lay eggs, but now dams on the main stream of the Yangtze River, shiplocks and lakes on the Yangtze River have completely blocked their way out. Under some dams, you can even see some migratory fish hit the wall and die.
There are more than 400 species of fish in the Yangtze River, ranking first among all water systems in China. For example, the famous Yangtze shad, with a catch of 654.38+0.974 and 654.38+0.57 million kilograms, is hard to find. Chinese sturgeon, white sturgeon and mullet are also rare.
The decrease of fish will definitely affect the survival of the first-class organisms in all parts of the food chain, such as the baiji dolphin, which has been basically extinct at present, and the number of finless porpoises has also decreased significantly; And waterfowl. In June, 2004, two wild waterfowl investigation teams in Hubei investigated 15 representative lakes, including Honghu Lake, Liangzi Lake and Zhangdu Lake, respectively, and found that only 60% of the previously recorded 102 species of waterfowl remained. Being at the top of the food chain, people will inevitably be deeply affected, especially fishermen who directly take fishing as their profession. Most of them turn from natural fishing to artificial farming.
Man-made river and lake barriers, on the one hand, let us try our best to rescue and protect the world-famous endangered species of baiji and Chinese sturgeon in the Yangtze River, on the other hand, artificially increase endangered species!
Dredge "Blood" for Mother River
There are many lakes in the Yangtze River basin, which are distributed in both plains and plateaus. All lakes in the plain area are freshwater lakes with a total area of about 22,000 square kilometers. The Yangtze River basin has four of the five largest freshwater lakes in China, namely Poyang Lake, Dongting Lake, Taihu Lake and Chaohu Lake. These Tongjiang lakes, like the "blood vessels" of the Yangtze River, play a vital role in stabilizing the Yangtze River ecosystem and maintaining species diversity.
Because they are connected with the Yangtze River, these Tongjiang lakes provide habitats for migratory fish and birds, enriching the biodiversity of the Yangtze River basin. These Tongjiang lakes are huge natural reservoirs, which have the function of regulating storage and can store excess water. Because of this storage capacity, in rainy season and flood season, it can divert excess water, regulate river runoff, reduce flood peak, find a place for flood throughout the year, thus reducing and controlling flood disasters. Taking Jianghan Lake Group as an example, in the wet year, it can generally receive more than 654.38+0.5 billion cubic meters of incoming water. 199 1 year, Poyang Lake is the accumulated flood storage of the Yangtze River 1 1 100 million cubic meters. Dongting Lake absorbed the floods from the four rivers and the Yangtze River, and then discharged into the Yangtze River from Chenglingji through the regulation and storage of the lake.
In the process of breathing with the Yangtze River, the lakes in the Yangtze River have stabilized their natural properties, slowed down the shrinking trend and enhanced their ability to degrade pollution. As a main form of wetlands, lakes have physical and biological purification functions for pollutants. Rich wetland biome can adsorb and degrade pollutants. The purification effect of lakes and wetlands is more obvious. Taking Dongting Lake as an example, Dongting Lake can maintain the title of "green lake" mainly because the wetland has a strong function of purifying water quality.
At first glance, it is a bit strange to divert water into the dike, return farmland to the lake, and turn "flood" into "great wealth"!
Most of the Yangtze River basin is in a typical monsoon climate zone. After entering the summer, the summer monsoon lingers to form a rain belt. Coupled with the heavy rain in the upper reaches of the Yangtze River, huge passenger flows to the middle and lower reaches, forming an annual flood season.
When the flood comes, where there is no accumulation, it will inevitably flood the areas where human beings live and form a flood. According to statistics, the area of lakes and ponds in the middle and lower reaches of the Yangtze River has dropped sharply, reducing the volume by more than 78 billion cubic meters. Dongting Lake, for example, was once the most important storage lake in the Yangtze River and was known as the "stomach of the Yangtze River". Since the beginning of the 20th century, its area has shrunk from more than 6,000 square kilometers to 2,700 square kilometers at present, a decrease of two-thirds. The shrinking stomach of the Yangtze River has very limited water storage function, so as long as there is flood, it will be submerged.
People choose to live and produce on the alluvial plain along the river. With the intensification of the utilization intensity of alluvial plain, the pressure caused by flood is increasing day by day, and people begin to build dikes around the lake. The more dams are built, the higher they are ―― a unique "dam economy" appears. In this economic model, a series of production activities are related to flood dike and irrigation and drainage system.
At first, the economic land around the dike was very fertile, and many "land of fish and rice" appeared. However, with the intensification of land reclamation around the lake, the ecological resources are unbalanced, but the flood is getting bigger and bigger, and the production cost is getting higher and higher. Whether farmers, local governments or the state, the investment in dike economy has exceeded their affordability. As a result, the dam was repaired every year, the paddy field was planted every year, and it suffered losses every year.
From a scientific point of view, flood is also a valuable water resource. The high levees now built on both sides of the Yangtze River simply discharge the water resources of the Yangtze River directly into the sea at the fastest speed. The function of wetland in storing water in rainy season and slowly discharging in dry season is completely lost, and the frequency of water stoppage and drought in the Yangtze River in winter is increasing.
After the flood in the Yangtze River basin from 65438 to 0998, the work of "returning farmland to lakes and leveling ridges for flood discharge" began, but land-lost farmers need new alternative industries, otherwise the achievements of returning farmland to lakes and wetland restoration will be difficult to consolidate. Therefore, it is particularly necessary and urgent to develop "flood economy" as an alternative industry after wetland restoration. From a scientific point of view, economic development and environmental protection are not contradictory. The way out is to restore wetlands, discuss the sustainable utilization of wetlands with local communities, and maximize various benefits of wetland ecology.
For a long time, people have been pursuing the use of wetlands to turn them into farmland. Scientific calculation shows that wetland is the most productive ecosystem, and its value is not limited to the production of grain and aquatic products. Relying on wetlands, develop aquaculture, eco-tourism, characteristic planting and breeding, grassland animal husbandry, forestry and forest products processing industry, form an industrial cluster with wetland characteristics, and form a chain for the development of general dikes, flood storage dikes and key dikes to replace industries. The Yangtze River flood can be regarded as.
The biggest feature of the middle and lower reaches of the Yangtze River is the huge wetland lakes, which are rich in water resources and have many wetland products, and have great competitiveness all over the world. As long as the middle and lower reaches of the Yangtze River develop the characteristic wetland economy, it will have a place in both the domestic market and the global market.
The floods in the Yangtze River can be turned into "floods" or "great wealth". Comply with the flood, rely on the flood, and the flood is the available resource. In the near future, the flood economy and wetland industrial clusters in the middle and lower reaches of the Yangtze River will present a moving picture of grass, fat cattle and fragrant lotus roots.