1. Review of the Yellow River cut-off

(1) cut-off condition

Since 1972, the Yellow River has naturally stopped flowing, mainly in the downstream Shandong section. In the 28 years from 1972 to 1999, except 1973, 1977, 1984, 1985, 1986.

Table 5- 14 Statistics of the Yellow River's cutoff over the years

Note: The uninterrupted years are not listed in the table.

Since 1990s, the Yellow River has been cut off for a long time, and the cut-off time has been advanced. From February 7th 1997, the cumulative deadline (profit) reached 226d, reaching 13 times.

(2) cut-off characteristics

According to statistics in recent years, the Yellow River has the following characteristics:

1) The cutoff frequency is increasing. The Yellow River was cut off for six years in the 1970s and seven years in the 1980s. In 1990s, it was cut off for nine consecutive years from 199 1 to 1999. The cutoff frequency increased from 0.6 in 1970s to 0.9 in 1990s.

2) The deadline is extended. After entering the 1990s, the number of days of cutoff in the lower Yellow River (including intermittent and all-day cutoff) increased rapidly. From more than ten days in 1970s and 1980s to 100d in the middle and late 1990s, 1997 reached the record of 226d.

3) The influence scope of network disconnection is constantly expanding. Compared with the number of dry days, the length of dry river section fluctuates greatly. However, since the 1990s, the interception distance from the estuary has been increasing, only about 199 100 km in 0 year, reaching above the section of Jiahe beach at 100 km. The cut-off length accounts for 88% of the length of the river below Huayuankou. During the period of 1997, the downstream river was cut off to the vicinity of Liuyuankou in Kaifeng, with a cut-off length of about 703km.

4) For the first time in the year, the deadline was advanced and the range of intensive deadline months was expanded. Before 1990s, the first cutoff occurred in April, and the cutoff time was mainly from May to July. After the 1990s, the earliest deadline was advanced to 65438+ 10 month, and even a cross-year deadline appeared. The intensive shutdown month lasted from March to July.

2. The socio-economic impact of the Yellow River cutoff

The Yellow River is the lifeline along the Yellow River, and the social and economic impact caused by the interruption of the Yellow River is mainly reflected in the economically developed downstream areas. Although the area of the lower reaches of the Yellow River is not large, the production and domestic water of Jinan, Zibo, Dongying, Shengli Oilfield and other large and medium-sized cities in the peninsula are directly sourced from the Yellow River. In addition, there are several large irrigation areas for diverting water from the Yellow River. The interruption of the Yellow River has seriously affected the downstream areas, especially the industry, agriculture and oil field production along the Yellow River in Shandong Province.

According to the preliminary investigation and analysis of relevant departments, the accumulated economic losses of industry and agriculture (including oil fields) due to water shortage in the lower reaches of the Yellow River 1972 to 1996 are about 26.8 billion yuan, with an annual average of nearly1400 million yuan (price 1995). 1The direct economic loss caused by the interruption of the Yellow River in 1997 to industrial and agricultural production in Shandong Province13.5 billion yuan, including 7 billion yuan for agriculture, 4 billion yuan for industry and 2.5 billion yuan for others.

(1) Impact on downstream agriculture

The lower reaches of the Yellow River and the areas along the Yellow River in Shandong Province were originally characterized by "spring drought, summer waterlogging and late autumn drought". The cut-off of the Yellow River usually occurs at the peak of irrigation water consumption. The lower reaches of the Yellow River, which is the main water source, are short of water all the year round, which leads to the failure of timely sowing and irrigation of farmland in irrigation areas, agricultural production reduction, and total production in estuary areas in some years. Agricultural economic losses accounted for 45.5% of the accumulated losses of industry and agriculture caused by water stoppage. 1997 The Yellow River was cut off, farmland in Shandong Province was irrigated without water, and there was a serious drought 107× 104hm2, 50× 104hm2, which led to crop failure and grain yield reduction of 27.5 × 108. There are 2,500 villages along the Yellow River, and 6.5438+0.3 million people have difficulty drinking water.

(2) Impact on downstream industries and life

The interruption of the Yellow River has brought great harm to the industrial production and people's life in the downstream coastal areas. During the period of 1995, many industrial enterprises in the lower reaches of the Yellow River stopped production due to lack of water, resulting in direct economic losses of more than 4 billion yuan, of which Shengli Oilfield reduced production by 26× 104t, with a loss of 200 million yuan. 1997 is the most serious year of water shortage. 200 oil wells in Shengli Oilfield were forced to shut down, and the local tap water price rose to 1.8 yuan /m3. Some residents are infected with gastrointestinal diseases because of drinking unclean water sources.

3. Cause analysis of disconnection

It is generally believed that the cutoff of the Yellow River is caused by increasing water transfer, wasting water resources and poor management in coastal areas on the basis of the lack of water resources in the Yellow River basin, and some of them are also affected by climate change in recent years. Its causes can be divided into two categories: natural factors and human factors.

(1) natural factors

The Yellow River basin basically belongs to the continental climate zone, with an average annual precipitation of 466 mm. The average natural runoff for many years is only 580× 108m3, accounting for only 2% of the national runoff. The per capita water quantity in the basin is 593m3, which is only 25% of the national average water quantity. The average water consumption per mu of cultivated land is 324m3, which is only 17% of the national average. Water resources in the Yellow River basin are inherently poor. Since 1970s, the precipitation in the basin has decreased. The average precipitation in the watershed above Huayuankou in 1970s and 1980s was 5% less than that in 1950s and 1960s, 1990 ~ 1995 less 12%. Due to the general drought in the Yellow River basin, the runoff into the Yellow River decreases and the water diverted from the Yellow River increases. These are the objective reasons why the Yellow River is cut off.

(2) Human factors

Most scholars in China believe that the interruption of the Yellow River is mainly caused by human factors, the most important of which is the sharp increase in water diversion from the Yellow River.

Since the 1950s, with the social and economic development along the Yellow River, the water consumption for diverting water from the Yellow River has obviously increased. By the 1990s, it reached 65% of the natural runoff (the average natural runoff above Lijin 1990 to 1995 was 458× 108m3), and the water consumption was extremely amazing.

At the same time, there is a serious waste of water diversion from the Yellow River. In addition, the existing water conservancy storage project can not meet the needs and the water management is not good, which greatly increases the possibility of the Yellow River cutting off.

With the rapid increase of water demand caused by human activities and the storage of water conservancy and soil and water conservation projects, the natural runoff in the lower reaches of the Yellow River will continue to decrease. If we do not actively interfere with human activities, the Yellow River will continue to cut off and the degree will become more and more serious. 1995 The Investigation Report on the Impact and Countermeasures of the Yellow River Cut-off published by the Nature Protection Department of the State Environmental Protection Bureau predicted that the longest horizontal cut-off duration of Lijin section in 2000 was 140d, and that in 20 10, the horizontal cut-off duration was more than 200d, but in fact, the cut-off duration of 197 had reached 226d, 65437.

(3) the comprehensive impact of the imbalance of ecological environment in the basin

Compared with other parts of the country, the ecological environment quality of the Yellow River Basin is relatively poor, and the most obvious manifestation is the lack of forests. Due to the low forest coverage, soil erosion in the middle and upper reaches of the Yellow River is very serious. When it rains, especially heavy rain, it will not be able to keep water. Soil erosion modulus can reach (2 ~ 3) ×104t/(km2 a), which directly leads to a huge amount of sediment in the Yellow River. It is also inseparable from the fact that the Yellow River can be cut off for several months in dry season and frequent floods in wet season.

The cutoff of the Yellow River mainly occurs in the lower reaches, and the runoff changes seasonally, but the essence of the problem is the change of hydrology, water resources and ecological environment in the whole basin, which seriously interferes with and weakens the self-regulation and self-organization ability of the river ecosystem and is difficult to restore order and stability.

4. Countermeasure analysis and evaluation

The cutoff of the Yellow River has aroused widespread concern from all walks of life, and experts and scholars from all walks of life have put forward various schemes and countermeasures to solve the problem of cutoff of the Yellow River. These countermeasures can be roughly divided into engineering countermeasures and management countermeasures. The former hopes to achieve the goal of not cutting off runoff by adding new water conservancy projects, citing water resources from other basins or adjusting the distribution of annual runoff to a greater extent. The latter focuses on formulating and improving the management measures of water resources on the basis of existing water conservancy projects, and objectively increasing the available amount of water resources through saving and rational allocation.

(1) engineering countermeasures

The engineering countermeasures mainly include: ① stepping up the construction of the main stream regulation and storage project to increase the runoff regulation capacity in the middle and lower reaches of the main stream; (2) build plain reservoirs and underground reservoirs to store them in abundance and use them in dry seasons; (3) Make rational use of groundwater and implement the irrigation method of "combining canal with well"; ④ Building the South-to-North Water Transfer Project to increase the water resources in the basin; ⑤ Reduce the amount of sediment coming from the Yellow River and the amount of water used for sand washing.

(2) Management countermeasures

Management countermeasures are mainly based on two aspects, one is to strengthen the rational allocation and management of water resources in the whole basin, and the other is to take "throttling" measures to realize the sustainable utilization of water resources. Therefore, improve the management mechanism, unified management and unified dispatching of the Yellow River water resources; Formulate a reasonable water resources allocation scheme; Raising water prices and vigorously implementing water-saving measures have become the main countermeasures to strengthen management in the future.

(3) Comprehensive evaluation of existing countermeasures

As can be seen from the above, the engineering countermeasures mainly focus on "open source" and sediment prevention, that is, improving the regulation and utilization of water resources, or finding another water source. Countermeasures include building a number of large-scale water conservancy projects; Vigorously promote small and medium-sized water conservancy and soil and water conservation projects, and actively carry out the preliminary work of the South-to-North Water Transfer Project. However, many of these projects are still in the process of demonstration or preliminary investigation, and some are still under planning, so it will take a long time to officially start and play a role. It only needs to build a silt dam to intercept sediment, which has small investment and quick effect. In addition to the negative impact on ecology, it is still suitable at present.

The key point of management countermeasures is to tap the potential on the existing basis, including improving the management and distribution of water resources and improving water-saving technology, so as to achieve the purpose of "throttling". The former is generally regarded as a top priority and the most effective means to alleviate the recent network disconnection problem.

According to the current situation, combined with the changes of natural environment and human factors in the future, the water shortage in the Yellow River Basin will not be alleviated for a long time. Therefore, if effective measures are not taken, the phenomenon of Yellow River cutoff will occur frequently in the future, and it may become more serious, and its social, economic and ecological environmental impact will increase.

It is worth mentioning that at the beginning of 1999, Shandong Province formulated the Measures for the Administration of Yellow River Diversion in Shandong Province. Under the protection of laws and regulations, although the inflow of the Yellow River in Dongying in 1999 decreased by more than 40% compared with the second dry year of the Yellow River in history 1998, the water supply was stopped for only 40 days. As of May 20, 2000, there was no interruption in the lower reaches of the Yellow River. This shows that in the short term, it is feasible to prevent the cutoff of the lower Yellow River by scientific management means (planned water transfer).

Second, the East Route of South-to-North Water Transfer Project (Shandong Section) on the impact of the region and countermeasures

1. Planning and prospect of water transfer project

The East Route Project of South-to-North Water Diversion is built on the basis of the existing South-to-North Water Diversion Project. The Yangtze River water is pumped from Jiangdu, Yangzhou in the lower reaches of the Yangtze River. It is pumped northward step by step by using the Beijing-Hangzhou Canal and its parallel rivers, and is connected with Hongze Lake, Roman Lake, Nansi Lake and Dongping Lake to play a role in storage. After leaving Dongping Lake, water is delivered in two ways: southbound, crossing the Yellow River through a tunnel near Yishan; The other road goes east, passing through Jiaodong water trunk line to Yantai and Weihai. The total length of the water conveyance trunk line is 1 156km, including 646km south of the Yellow River, crossing the Yellow River 17km, 493km north of the Yellow River and 70 1km in Jiaodong.

The Shandong section of the East Route of South-to-North Water Diversion Project enters the Hanzhuang Canal from the Zhong Canal to Taierzhuang, and enters the canal and river storage via Nansi Lake and Dongping Lake to supply water to the north of the Yellow River and Jiaodong area respectively. The water supply line to the north of the Yellow River crosses the Yellow River through the tunnel, enters Hebei via the Wei Canal in Linqing City, and builds a branch line in Linqing City to connect the river and the river to Datun Reservoir to supply water to Dezhou. The water supply line leading to Jiaodong area takes water from Qinglong Gate of Dongping Lake, and enters the whole Jiaodong Peninsula east of Jinan through the Jiaodong water main canal.

The South-to-North Water Transfer Project has formed a T-shaped artery in Shandong Province, with a length of 487km from north to south and a width of 704km from east to west, with a total length of 1 19 1km. The water supply area covers Jinan, Qingdao, Yantai, Weihai, Zibo and other 14 cities and 107 counties and cities.

After the implementation of this project, the water supply artery in Shandong Province (including the peninsula) will be formed from south to north and from west to east, and it can be connected with Jinan Yellow River Diversion Project, Huangjizi Water Diversion Project, Yellow River Diversion Project, Yellow River Diversion Project and Yellow River Diversion Project, forming a large-scale water supply network in Shandong Province and realizing joint local water dispatching. The Yellow River water and the Yangtze River water will play an extremely important role in the optimal allocation and rational dispatch of water resources in the whole province and the peninsula. According to the principle of first urgency and then delay, it will be implemented step by step and benefit step by step, and finally reach the design scale.

1) During the Tenth Five-Year Plan period, the second-stage dam pumping station and the third-stage pumping station of Ji Liang Canal will be implemented, and the water resources control project in the west of the lake will be completed, so as to realize the joint dispatching of water resources in Nansi Lake and Dongping Lake. Complete other key projects of South-to-North Water Transfer Project before 20 15, and let Yantai and Weihai use the Yangtze River water.

2) Jiaodong water main line project. This project is the backbone project of transferring water from Dongping Lake to Jiaodong, an important part of the South-to-North Water Transfer Project, and a key project to realize the joint dispatching of water resources in the whole province. It should be actively planned and implemented as soon as possible. During the Tenth Five-Year Plan period, the Jiping main canal will resume its expansion, the water conveyance project above Jinan will be completed, and the water conveyance project east of Jinan will start. By 20 10, the west-to-east gas transmission project and the Yellow River diversion project will be completed.

3) Jiaodong Emergency Water Transfer Project. Before the implementation of the East Route of South-to-North Water Transfer Project, in order to solve the increasingly serious water supply crisis in Yantai and Weihai, the Yellow River water was urgently transferred to Yantai and Weihai by tapping the potential of the Yellow River Diversion Project. During the Tenth Five-Year Plan period, the first phase project of Ji Yan and Jiwei will be completed, so that both places can use the Yellow River water. Expansion, matching and improvement will be carried out before 20 15, and it will be connected with the east route project of South-to-North Water Transfer Project, which will fundamentally solve the serious shortage of water resources in the two cities and provide reliable water supply guarantee for the sustained economic development and the continuous improvement of people's living standards in this area.

2. Prediction of water resources after the implementation of water transfer project.

The East Route Project mainly uses the river channel to transport water, and adopts the method of building pumping stations step by step to lift water to the north, which is relatively flexible in both water delivery channels and water delivery power. Therefore, the reasonable water transfer scale of the East Route Project can be flexibly adjusted within a certain range according to the water demand of the receiving area in different periods.

According to Zhang Ping's calculation of the optimal allocation model of water resources in this region, it is found that domestic, environmental, waterway and industrial water can be met in 20 10 and 2030, but agricultural water is still in short supply. The water shortage in 20 10 is 9.35× 108m3 and the water shortage rate is10.74. In 2030, the water shortage was 6.72× 108m3, and the water shortage rate was 7.90% (Table 5- 15, Table 5- 16).

Table 5- 15 Optimal Allocation Scheme of Water Resources in Horizontal Year 20 10

sequential

Table 5- 16 Optimal Allocation Scheme of Water Resources in 2030 in Horizontal Year