my country’s water resources and constraints on urban development

Zhao Lunshan

(China University of Geosciences (Beijing))

"Water and cities" are very complex issues of great significance to the current social and economic development of our country and the world. subject. For a long time in my country's economic construction, water resources issues have confused, worried and debated the whole society. At the same time, they are also a major problem that needs to be solved urgently. Focusing on this theme, this article believes that the understanding of my country's water resources status and its restrictive effect on urban development is of most fundamental and critical significance. At the same time, it is also the most grounded issue for earth science to conduct research and analysis on. This article only discusses this point using Beijing as an example, and proposes a solution to the water shortage in North my country.

The Earth is the only planet in the known universe with liquid water. Water has given birth to life on the Earth and also nourished human civilization. Water is an extremely important basic material condition for human survival and social and economic development. Nature has endowed mankind with the most precious water resources. However, because water on the earth follows its own inherent laws of circulation, the available water resources are very unevenly distributed in time and space. Some inland and arid countries are short of water, and coastal areas Too much rain sometimes causes disasters. Our country has a vast territory and a long coastline. Due to the constraints of the particular climate, regional geology and terrain conditions, there are many unfavorable factors in the allocation of water resources: the area of ??the southeastern coastal zone with abundant water resources is not large enough, while the inland water-scarce areas exceed the land area. More than half, so overall it is a country with insufficient water resources. However, my country is not a country absolutely short of water. The main contradiction is that the spatial and temporal distribution of precipitation is extremely uneven. Therefore, with the current rapid development of my country's social economy and rapid urbanization, the rigid demand for water resources continues to grow. At the same time, there are factors such as the background of global climate aridity and insufficient water management, resulting in a long-term situation of "more water, less water". , muddy water, dirty water and uneven water” embarrassing situation. It has seriously affected and restricted the development of the cause of building a moderately prosperous society in an all-round way. At present, whether we can fully tap the potential of water resources and scientifically allocate and manage water conservancy to achieve the goal of ensuring water supply to the greatest extent possible is a test of the wisdom of our contemporary people, especially the scientific and technological team. Our ancestors once gave excellent answers. In the history of our country, we have made achievements in flood control, drought relief, water conservancy irrigation and water transportation that we can be proud of. Many contemporary developed countries have also created advanced, high-efficiency projects for water resource development, utilization, and flood prevention and control based on their own land conditions. The effective development and scientific management of my country's water resources can only be found by relying on the wisdom and innovation of the Chinese people.

1. Urban development is strongly restricted by water resources conditions: Take Beijing as an example

(1) History of water resources development in Beijing

Beijing is located in Xishan and Jun On the piedmont highland formed by the intersection of mountains and the alluvial plain formed by the deposition of four river systems, the northwest is high and the southeast is low and open to the sea. In ancient times, the Beijing area had crisscrossed rivers and springs, dense lakes and wetlands, complete types of surface and underground water resources, and abundant reserves. It had superior conditions for population settlement and city building. Beijing has a history of 3,000 years since it was founded as a city, and it has a history of nearly 800 years since it was designated as the capital of the Yuan Dynasty in the Yuan Dynasty. With the growth of the capital's population and economic aggregate, each stage is accompanied by the development and utilization of water resources of different nature and occurrence to meet the needs of the city. A brief history of Beijing's water resources development is shown in Table 1.

Table 1 History of urban and population development and water resources development in Beijing

Continued table

As can be seen from Table 1, as Beijing expands its urban scale and increases its population, Various types of water resources must be continuously developed: from surface water to groundwater, until the development of ultra-deep groundwater, water supply from the suburbs of the city to the outer suburbs to neighboring provinces, and even diversion and storage of water from distant rivers, such as the water source of the Sanggan River in the upper reaches of the Yongding River in the Luliang Mountains; and to divert water from the Yangtze River. From 2007 to 2009, Beijing's population increased dramatically. In addition to overexploitation of deep groundwater, almost all methods were used, such as developing reclaimed water and increasing artificial rainfall. At present, Beijing's water resources development has reached its limit, and the amount of water resources per capita in Beijing continues to decline.

(2) Current water resources situation and bottom line in Beijing

According to a 2007 report, Beijing’s annual water consumption is 3.4 billion to 3.6 billion cubic meters, and the current annual water supply is 2.6 billion cubic meters, the gap is 1 billion cubic meters. Currently, five methods are used to ensure Beijing’s water supply: ① Over-exploitation of groundwater. From 2000 to 2007, the city’s cumulative over-exploitation of groundwater was 5.6 billion cubic meters. This caused the groundwater level in the area to drop, as shown in Figure 1. ② Expand recycled water, develop reclaimed water, and improve utilization rate. ③Save water. ④ Waiting for foreign aid to provide water supply, it was expected that water from the Yangtze River would be transferred to Beijing in 2010, partially alleviating Beijing's water difficulties (Beijing TV, February 15, 2007). ⑤ Divert water from Hebei and Shanxi to protect Beijing. In 2010, the South-to-North Water Diversion Project failed and had to wait another five years. Therefore, the current water resources situation in Beijing is extremely pessimistic. According to statistics in 2006, Beijing’s multi-year average rainfall was 585 mm, equivalent to a total precipitation of 9.828 billion cubic meters, resulting in 1.772 billion cubic meters of surface runoff and 2.559 billion stored in groundwater sources. cubic meters; the total amount of locally produced water resources is 3.739 billion cubic meters. However, in the past 10 years, Beijing's annual rainfall has decreased by 10% to 20%, and it is unlikely that rainfall will increase.

Calculated based on Beijing's 2005 population, the per capita water resources are 248 cubic meters, which is 1/8 of the country's per capita water resources and 1/20 of the world's per capita water resources; ranking 100th among 120 capitals in the world. after. Calculated based on the population in 2009, the per capita amount of water resources is less than 200 cubic meters.

Figure 1 Schematic diagram of the decline of groundwater levels in the urban and suburban areas of Beijing over the same period over many years

(3) Planning, reality, controversy and solutions

Newspaper reports in January 2011 : Beijing’s permanent population at the end of 2009 was 19.72 million; according to the “Eleventh Five-Year Plan”, Beijing’s population in 2008 was 16.25 million, exceeding about 3 million people. It is planned that Beijing’s population will reach 18 million in 2020, exceeding the plan 10 years ahead of schedule. The "Eleventh Five-Year Plan" population plan is already aggressive; the fact is that the average annual population growth during the "Eleventh Five-Year Plan" is 543,000, which is 200,000 more than the average annual increase during the "Tenth Five-Year Plan" period. Currently, we must face a breakthrough of 20 million. The test of the population mark. Beijing is currently facing a crisis situation of population explosion and water resource depletion. Where is the bottom line for Beijing’s water resources? According to a study by the Beijing Geological Survey Bureau, the total groundwater reserves within a depth of 150 meters in Beijing are 60 billion cubic meters; Beijing’s average annual water supply gap from 2001 to 2008 was 1.27 billion cubic meters, with a cumulative shortage of 10.2 billion cubic meters. . In the 1960s, the depth of water wells drilled was less than 100 meters, but now all the 100-meter deep water wells in plain areas have become abandoned wells, and new wells are being drilled as deep as 150 meters. If the water supply is based on a population of 25 million, Beijing's groundwater will be completely exhausted in about 20 years. This is the bottom line of Beijing’s water resources.

The reason why Beijing has experienced a population explosion in recent years is related to the paradoxical understanding that has emerged for a period of time. Some economists and media people have a negative attitude towards the formulation of "the limit of urban population carrying capacity". Practice has proved that urban development and population size are strictly restricted by natural basic conditions. In northern my country, the first is the limitation of water resources. On March 17, 2011, Wu Yongping, a member of the Beijing Municipal Committee of the Chinese People's Political Consultative Conference and a professor at Tsinghua University School of Public Policy and Management, suggested "dispersing some functions of the capital to surrounding areas" and pointed out that this problem should be resolved with determination by the central government. The author agrees with the witch committee member's suggestion. Beijing’s urban functional positioning and population size should be planned strictly in accordance with the concept of the Scientific Outlook on Development.

However, even if the population is reduced strictly in accordance with Beijing’s original plan, in line with the standard requirements of building a “world city”, it is still necessary to open up a cheap new water source with large flow and stable water supply for Beijing. This article suggests Starting from solving the water shortage problem in North China, we searched for water sources across the country and proposed a solution to divert water from the Yangtze River to Beijing.

2. my country’s water resources situation and in-depth development potential

(1) my country’s overall water resources situation

my country has a vast territory, complex climate and terrain, and is affected by the monsoon It affects the extremely uneven distribution of precipitation across the country; in terms of geological structural background, due to the continuous uplift of the Qinghai-Tibet Plateau since the Permian, the terrain in the southwest has been formed to be steep and high, and it has dropped sharply to the low and broad plains to the east, forming a stepped steep terrain, consisting of This causes the river to flow rapidly, carry a large amount of sediment, and the soil layer is thin, which is not conducive to storing groundwater and buffering the river flow rate. This is the geological background that causes frequent floods and droughts. According to the annual report of the Ministry of Water Resources, the national average precipitation in 2004 was 600.6 mm, equivalent to a total precipitation of 5,687.64 billion cubic meters. The total water resources occupied by the country that year was 2,412.96 billion cubic meters, 12.9% less than the average of 2,812.44 billion cubic meters in the past 40 years. Ranked 6th in the world. my country's per capita water resources are 2,300 cubic meters, which is 1/4 of the world's per capita water resources. It ranks 21st in the world and is listed by the United Nations as one of the 13 water-poor countries in the world. The average amount of water resources per mu of cultivated land in my country is 1,770 cubic meters, which is 3/4 of the world average. China's population accounts for 22% of the world's total population, but renewable fresh water accounts for 8% of the world's total. Generally speaking, my country's water resources are not abundant enough. The per capita and average water amounts per mu are small. Water resources are unevenly distributed among regions, between years and within years, which are unfavorable factors due to natural conditions. Floods and droughts have been frequent in our country's history. Coupled with the overall global warming in recent years, water shortage areas have increased. Currently, nearly 400 of the country's 655 cities are short of water, of which about 200 are seriously short of water.

my country's water shortage situation has significantly worsened in recent years, as shown in the following: reduced rainfall in North China, consecutive droughts in winter and spring from 2010 to 2011, Shandong and Henan suffered the worst drought in 60 years, and drought intensified; the vast northwest Drought and water shortages persist in the region; there was a severe drought in the Yunnan-Guizhou Plateau in the spring and summer of 2010, and severe droughts in Chongqing for consecutive years; in recent years, Guangdong, Guangxi and Fujian have suffered from insufficient rainfall due to weakened typhoons, and the drought in southern China has attracted attention. The frequent occurrence and expansion of floods and droughts in recent years are not only due to natural and irresistible factors, but also related to certain gaps in water resources management across the country.

(2) my country’s water resources potential needs urgent re-evaluation

As to whether my country’s water resources still have development potential, there have been different opinions for many years. One opinion is that my country’s water resources still have development potential. The resources have no development potential. The only way to solve the water problem is to save water and prevent and control pollution. Vigorously promoting water conservation, such as improving agricultural irrigation efficiency, adjusting water prices, and controlling water pollution, are all necessary and effective water control measures.

However, in terms of in-depth development of water resources, the experience of some grassroots water conservancy departments deserves attention and promotion. For example, the Shandong Provincial Department of Water Resources has summarized the water conservancy management idea of ??"flood resource utilization" and a set of water conservancy management and engineering measures to solve flood storage and drought prevention based on years of practice in managing water conservancy in the province, ensuring that the province's social development and economic construction have a growing impact on water resources. need.

From the perspective of overall precipitation, my country is not a country that is absolutely short of water: the national average annual rainfall is 600.6 mm, and the per capita water resource is 2,300 cubic meters. The problem is that a large amount of water flows into the sea by air or is evaporated. . Recovering the ineffectively lost water resources through investigation and research and certain engineering measures, that is, adopting the policy of "increasing revenue and reducing expenditure" to manage water conservancy is an effective and feasible way for our country to overcome the water crisis. The countermeasures proposed by Shandong Province to combine flood control with resource utilization and turn harm into benefit are in line with the "Integrated Management of Water Resources and River Basins" and "Sustainable Water Management" proposed at the Fifth World Water Conference held in Beijing in September 2006. "Contemporary water resources development and protection concept.

(3) Five suggestions for the in-depth development of my country’s water resources

(1) Evaluate the development and utilization rate of water resources in large rivers and lakes across the country. Table 2 is some data quoted from the article "Preliminary Study on Water Resources Development and Utilization Efficiency of the Yangtze River Basin" in "Water Conservancy Planning and Design" Issue 1, 2010, with supplements.

Table 2 The development and utilization rate of water resources in some large river basins and lakes in my country

As can be seen from Table 2, in addition to the high development and utilization rates of the Haihe River and Taihu water systems, there are also a considerable number of rivers in my country. The development and utilization rate of lakes is not high, especially for rivers and lakes in the south. In order to solve the frequent drought problems in the south, sufficient planning should be carried out, engineering tests should be carried out, and in-depth development and utilization should be carried out. Due to severe drought in northern my country, some water areas have been over-exploited, such as the Yellow River drying up and groundwater overexploitation in Beijing and Hebei. Early research and countermeasures should be taken to solve this problem. However, in view of my country's national conditions, the generally accepted international understanding that the development and utilization of water resources in river basins should not exceed 40% needs to be reconsidered. In short, major rivers and lakes across the country urgently need to conduct an investigation, research and assessment of the current water resources and pollution status, as well as in-depth development potential.

(2) Use the "salt water storage" engineering measure to store fresh water from rivers into the sea. According to the "China Water Resources Bulletin" of the Ministry of Water Resources, the total precipitation in the Yangtze River Basin in 2004 was 1,854.68 billion cubic meters, but the amount of available water resources in the region was only 875.46 billion cubic meters. Nationally, these figures are: 5,687.64 billion cubic meters and 2,412.96 billion cubic meters. That is, about 42.4% to 47.2% of precipitation is lost, mainly by evaporation or flowing into the sea. In 2004, the amount of water entering the sea from the Yangtze River Estuary was 797.4 billion cubic meters, and the national volume was 1,292.1 billion cubic meters. Through certain engineering controls, part of the fresh water entering the sea can be diverted and stored, and transported to the arid areas of the north. After years of water replenishment, the water resources in the north will be greatly increased and drought alleviated. This idea of ????water control existed in ancient my country and was called "protecting salty water and storing fresh water". It is an effective form of flood resource utilization and making up for the deficit with abundance.

(3) Reasonable development of snowmelt water on the Qinghai-Tibet Plateau. The Qinghai-Tibet Plateau covers an area of ??2.3 million square kilometers and has an average altitude of 4,500 meters. It is known as the "Roof of the World" and the "Third Pole of the Earth". Since the Permian began to uplift 240 million years ago, it has formed a plateau ice sheet with an area of ??59,406 square kilometers and a total volume of 5,590 cubic kilometers. The average water resource runoff is 359 billion cubic meters, forming a unique country in the world. A sovereign "solid reservoir" whose snowmelt water is the source of seven of Asia's great rivers. Due to global warming, the plateau ice caps began to melt in the 1960s, and the source of the Yangtze River retreated by 50 meters every year. The Qinghai-Tibet Plateau is a unique treasure land of our country, and the world's third-pole ice layer is a solid reservoir over which our country enjoys sovereignty. However, over the years, we have not done enough research and development on the snowmelt water on the Tibetan Plateau. The total number of glaciers is 46,298, and only a few hundred have been observed and have data. Glacier melting is a very complex phenomenon. On the one hand, the ice and snow are melting, continuing to grow in some places, and the plateau is still rising. There is a certain balance of payments. Recently, it was reported that the area of ??plateau lakes is expanding, and the water source comes from melted ice and snow. As a water resource, a large amount of melted snow water should be developed and utilized. If it is not studied or developed, it will not prevent the melting of ice and snow, and most of the melted water will be evaporated. Lost. The prerequisite for the development and utilization of plateau snowmelt is in-depth investigation and research.

(4) Heavy rain resource utilization. my country is a country prone to heavy rains. The occurrence of heavy rains is mainly related to strong air flow activities and certain terrain factors, and has certain spatiotemporal distribution rules. For example, heavy rains occur frequently in spring and summer rainy seasons in the middle and lower reaches of the Yangtze River in Jiangxi, Hunan and other provinces, and in places such as Xingtai and the eastern foothills of the Taihang Mountains in Hebei Province, local heavy rainfall often occurs. Heavy rain is destructive and may cause disasters, but heavy rain is also a kind of water resource. Certain engineering measures can be adopted in heavy rain-prone areas to prevent heavy rain from causing disasters and store it to turn harm into benefit. my country's grassroots water conservancy departments have summarized and accumulated many years of experience and should conduct in-depth research and promotion. In this regard, the Netherlands uses engineering measures to build "water squares" to store heavy rainfall and achieve the goal of scientific utilization of turning harm into benefit, which can be used as a reference.

(5) Development and utilization of boundary river water resources.

There are many large rivers in our country that cross the national border. Water resources belong to both countries. Among them, the water resources that originate in our country and flow out of the national border should attract special attention and be researched and developed. For example, in 2004, the water resources that flowed out of our country or flowed into international boundary rivers The total amount of water resources is 706.4 billion cubic meters, of which 585.5 billion cubic meters flow from the southwest rivers. In accordance with international law, we have the right to utilize and develop these water resources based on certain agreements with neighboring countries. In international relations, the ownership of boundary river water resources is a matter of national sovereignty and national interests and should be taken seriously.

The geographical and climatic conditions in various parts of our country are complex and ever-changing. Through a nationwide systematic water resources survey, more developable water sources can be found. In the aspects mentioned above, special water condition surveys should also be carried out first, and demonstration and project planning should be proposed based on certain engineering tests.

3. A solution to the water crisis in the north: Expanding the Beijing-Hangzhou Grand Canal to realize "south flood diversion to the north"

(1) A golden line connecting the north and south of the prosperous economic zone in eastern my country Waterway

The Beijing-Hangzhou Grand Canal, which is as famous as the Great Wall, was built in the Spring and Autumn Period. It was opened to Beijing in 1293 during the Yuan Dynasty, with a total length of 1,794 kilometers. It is the longest in the world and the earliest ancient canal in human history. Water conservancy projects. The Beijing-Hangzhou Grand Canal is a precious heritage left to us by our ancestors. After more than 2,000 years of vicissitudes, the ancient canal has played a significant and lasting role in promoting my country's social and economic development. It can be said to be a golden waterway that runs through the prosperous economic zone in eastern my country. It fully demonstrates the high creative wisdom of the Chinese nation and the advanced level of water conservancy development and utilization in my country's history.

In today's historical period when science and technology are highly developed and the country is building a moderately prosperous society in an all-round way, what role can the Beijing-Hangzhou Grand Canal play? How can the geographical advantages of the canal be used to expand and develop its shipping, water conservancy, water diversion, etc. Function is a question that many experts and leading departments have been thinking about in recent years. Such as the east-line water diversion project of the South-to-North Water Diversion Project, as well as shipping, development, water diversion and storage for irrigation in the provinces along the river, and the repair of canal historic sites. During the National "Two Sessions" in 2006, many members of the Chinese People's Political Consultative Conference put forward suggestions for repairing the canal's cultural relics and declaring the Grand Canal a world cultural heritage and conducted inspections. In 2007, the Shandong Provincial Government proposed that the eastern route of the South-to-North Water Diversion Project should take into account river development and achieve the goal of comprehensive water diversion and shipping functions, and invest in expanding the 101.19-kilometer high-standard navigable river from Dongping Lake to Jining within 10 years. The "canal fever" among people across the country continues.

Today, facing the plight of water resources in northern my country, the Beijing-Hangzhou Canal provides us with a ready-made water transportation channel. Its starting point in the southeast is the coastal area with abundant water resources, and its end point is Beijing, Tianjin, Hebei, Shandong, Henan, and Shanxi, which are the most water-scarce areas in North China. The provinces the canal passes through belong to offshore plains with little undulations, making construction easy. There are river channels that can be used to expand the river canal, and there is no need to expand the land acquisition. Therefore, the Beijing-Hangzhou Canal is expanded and developed to make it the best waterway to divert floods during the southern flood season and some fresh water flowing into the sea, and to flow to the arid areas in the north. The focus of the canal expansion is to transport water by artesian flow across the basin. On the basis of a large-scale increase in runoff, the canal will retain sufficient water volume and then perform large-region water resource allocation and management functions such as flood storage and drought relief.

(2) Goals and project feasibility basis for the expansion, development and utilization of the Beijing-Hangzhou Grand Canal

(1) Water source. The basis for expanding the water volume of the canal is the annual rainfall of 1,600 to 2,000 mm in the Yangtze River and Qiantang River basins in southeastern my country, and the spring floods caused by the huge runoff of the Yangtze River. In 2004, the amount of water flowing into the East China Sea through the Yangtze River reached 797.4 billion cubic meters, accounting for 61.71% of the country's total sea flow. Therefore, the Yangtze River Basin is the largest water resource area in my country. By building certain projects to divert and store floods, and channeling them into canals, the artesian flow can be directed to North China. Assuming that 1/20 to 1/10 of the Yangtze River's inflow into the sea, that is, about 100 billion to 200 billion cubic meters of water, is introduced into the canal, the canal can increase the runoff of nearly 2 to 4 Yellow Rivers. Through reasonable engineering measures, the water volume of the canal can be restored. Can be enlarged. The most basic project of the expansion is to widen and deepen the canal channel and open up multiple outlets to divert water from the Yangtze River.

(2) Achieve self-flow. The Yangzhou-Tianjin section of the Grand Canal is the first phase of the project, with a total length of approximately 1,150 kilometers. The ground at both ends is at low altitude. According to the Institute of Geography of the Chinese Academy of Sciences and others (1985), the bedrock level of the Yangtze River in the Yangzhou section of Zhenjiang is 10 to 40 meters lower than the base level of the Yellow Sea, and the sediment layer of the river bottom is 3 to 40 meters lower than the base level of the Yellow Sea. 10 meters. The multi-year average water level of the Yangtze River at Nanjing Station is 5.48 to 4.97 meters, with a peak water level of 10.22 meters in the flood season and a minimum water level of 1.54 meters in the dry season. For example, assume that the altitude of the Haihe River entrance in Tianjin is 0 meters. Based on this calculation, when the canal is dug to a depth of -2 meters (Yangzhou) to -15 meters (Tianjin) below the base level of the Yellow Sea, the average water level difference is 15 to 20 meters, and the water level ratio drops to more than 0.13 parts per 10,000 during the normal water period. , the water surface ratio drops to 0.10 parts per 10,000 during the dry season, which can realize artesian water diversion from the Yangtze River to Tianjin, including slow diversion during the high water level of the Yangtze River during the flood season and during the flat water period. In addition, the canal can also accommodate and digest floods from the Huaihe River, Yellow River, etc., and store them into the canal water system. The canal also functions as a plain reservoir.

(3) Projects related to the canal expansion project. Develop and construct the Grand Canal water system centered on the canal, including riverside lakes, tributaries, reservoirs, wetlands, and canals, and carry out dredging, desilting, and deep excavation.

In addition, projects such as embankments, dams, locks, and reservoirs were built at the intersection of the canal and five major rivers to regulate the direction and flow of the canal's water. The canal's ecological environment construction and canal historic site repair projects were also carried out to revitalize the ancient canal. and vitality, blooming with the wisdom of Chinese descendants in the 21st century.

IV. Conclusion

To sum up, Beijing’s development needs to be planned strictly in accordance with the scientific outlook on development and the concept of sustainable development. Beijing’s urban functional positioning, economic aggregate and The population size should be controlled based on the sustainable and stable supply of water resources with local and foreign aid. To solve the water resource dilemma in Beijing and Tianjin, we should start from the overall drought problem in North China. Water can be diverted from water sources across the country, but gravity water transfer is the best strategy. my country's overall water resources still have potential to be tapped, and it is recommended to implement a water conservancy policy that combines sources of income and expenditure reduction to control water resources. The expansion of the Beijing-Hangzhou Grand Canal project effectively utilizes the existing canal channels, lakes, canals and ponds and other existing land. It does not require expansion of land acquisition or resettlement. It will be highly profitable and risk-free after completion, and future generations will benefit in the long run. Make full use of modern science and technology to build a set of grand projects that are adapted to my country's national conditions, fully functional, efficient in operation, and technically leading the world in the 21st century. The long-term operation of the newly built canal's water diversion function and the scientific allocation and management of water resources in the large river systems in eastern my country will greatly change the water shortage situation in North China and effectively guarantee the rapid and sustainable development of my country's national economy.

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