2.2.1 Analysis of water supply volume and water supply structure

According to the definition of Beijing Water Affairs Bureau, water supply volume refers to the annual water demand requirement and the specified water supply guarantee rate at a certain level. Under the conditions, the amount of water that existing and planned water engineering facilities may provide to users is related to the engineering water supply capacity and water demand. Table 2.6 and Table 2.7 show the annual water supply structure of cities in the Beijing-Tianjin-Hebei metropolitan area: surface water accounts for 21.9%, groundwater accounts for 72.1%, and others account for 6.0%. In 2006, the total water supply in the Beijing-Tianjin-Hebei metropolitan area was 20.557 billion m3. Among them, local surface water is 4.501 billion m3, accounting for 22%; underground fresh water (including shallow water and deep confined water) is 14.820 billion m3, accounting for 72%; water diversion from the Yellow River is 586 million m3, which is diverted from the Yellow River to Tianjin for emergency supply to Tianjin and from the Yellow River to Hebei. The water volume of the Yellow River in Cangzhou includes 116 million m3 of brackish water, 520 million m3 of wastewater treatment and reuse, and a small amount of rainwater utilization and seawater desalination water.

Table 2.6 Water supply volume in the Beijing-Tianjin-Hebei metropolitan area in 2006 Unit: 100 million m3

Table continued

Note: Tianjin also directly utilized 1.4 billion m3 of sea water in 2006 m3 is not included in the water usage.

Data sources: Beijing Water Resources Bulletin 2006, Tianjin Water Resources Bulletin 2006, Hebei Hydrology and Water Resources Information Network.

Beijing’s water supply shows a growing trend, and the water supply structure is constantly changing. The total water supply was 17.84 billion m3 during the “Tenth Five-Year Plan” period, 21 billion m3 during the “11th Five-Year Plan” period, and 21 billion m3 during the “10th Five-Year Plan” period. During the Second Five-Year Plan period, it is expected to be 26.02 billion m3, with average annual supply of 3.57 billion m3, 4.2 billion m3, and 5.2 billion m3 respectively. Moreover, Beijing's water supply structure is also changing, with surface water and groundwater supply decreasing, and external water supply and recycled water supply increasing (Table 2.7).

Table 2.7 Water supply volume and structure in Beijing Unit: 100 million m3

Data source: Beijing Municipal Water Affairs Bureau official website: /Portal0/default40.htm

The total water consumption of various industries in the Beijing-Tianjin-Hebei metropolitan area in 2006 was 20.557 billion m3. Among them, urban water consumption (including residential, industrial, and environmental water) is 5.678 billion m3, accounting for 28% of the total water consumption; rural water consumption (including domestic, farmland irrigation, forestry, animal husbandry, and fishery) is 14.879 billion m3, accounting for 72% (Table 2.8 ). From the perspective of water use, it can be seen that agricultural water consumption still accounts for a large proportion and there is a lot of waste. The potential for water conservation and recycling of water is very large, and there is a big gap compared with developed countries.

Table 2.8 Water consumption in the Beijing-Tianjin-Hebei metropolitan area in 2006 Unit: 100 million m3

Data source: Beijing Water Resources Bulletin 2006, Tianjin Water Resources Bulletin 2006, Hebei Hydrology and Water Resources information network.

Take Beijing as an example. Beijing is a resource-based area with severe water shortage. It is one of the 111 extremely water-poor cities. It is also one of the three cities with the fastest decline in water storage in the country. Since 1997, Beijing’s per capita water resources have been less than 160m3, only half of the average level 20 years ago, only 1/15 of the national per capita level, 1/50 of the world’s per capita level, and even only the water level determined by the United Nations. It is 1/3 of the regional level where resources are severely lacking (per capita water resources are 500m3). Water shortage has become the first bottleneck restricting sustainable economic and social development. In 2008, Beijing's total water consumption was 3.51 billion m3, and the surface water, groundwater, and other water sources were 550 million m3, 2.29 billion m3, and 670 million m3 respectively, accounting for 16%, 65%, and 19% of the city's total water consumption respectively; industrial , domestic, agricultural, and river and lake environment water consumption were 520 million m3, 1.47 billion m3, 1.20 billion m3, and 320 million m3 respectively, accounting for 15%, 42%, 34%, and 9% of the city's total water consumption respectively (Table 2.9).

Table 2.9 Water consumption situation in Beijing from 2000 to 2008

Data sources: Beijing Water Resources Bulletin from 2000 to 2008, Beijing Statistical Yearbook 2009.

For big cities like Beijing, unreasonable water use structure is the main reason for water shortage. Beijing’s water use structure can be divided into industrial, agricultural and urban domestic water (Table 2.10, Figure 2.1). Beijing's total water consumption in 2000 was 4.040 billion m3. Among them, urban domestic water consumption (including residential, public, environmental water, etc.) is 1.339 billion m3, accounting for 33.14% of the total water consumption; agricultural water consumption is 1.649 billion m3, accounting for 40.82%, and industrial water consumption accounts for approximately is 26%. By 2008, the proportions of domestic, agricultural and industrial water were 51%, 34.19% and 14.81% respectively, and domestic and agricultural production water accounted for 85% of the city's total water consumption. From the analysis of water use structure, the proportion of domestic water continues to rise, and the proportion of agricultural water is still relatively large. The effect of water conservation and water recycling in Beijing is very significant. Total water consumption also showed a downward trend, from 4.208 billion m3 in 1980 to 3.51 billion m3 in 2007.

Table 2.10 Changes in Beijing's water use structure in 2008

Data source: For data from 1980 to 2000, refer to "Analysis of Change Trends and Driving Forces of Beijing's Water Use Structure", 2001 to 2008 data Compiled based on Beijing Statistical Yearbook 2009.

Figure 2.1 Beijing’s water use change trend chart

From the data analysis in Table 2.10, Beijing’s water use structure and change trend in the past 30 years show the following characteristics: the proportion of industrial water use decreased by 17.17%; And tending to be stable; the proportion of agricultural water use decreased by 23.94%, but the proportion is still large; domestic water consumption increased rapidly, and the proportion increased by 41.21%. The structural problems of urban water use in Beijing have become prominent.

2.2.3 Analysis of water supply balance

According to the analysis in Figure 2.2, the annual water supply in the Beijing-Tianjin-Hebei metropolitan area can reach a balance. However, this balance is based on the amount of water resources in the region. This is achieved due to insufficient groundwater, over-exploitation of groundwater, large-scale introduction of foreign aid water, deterioration of the water environment, and low utilization rate of recycled water.

Figure 2.2 Histogram of water supply in the Beijing-Tianjin-Hebei metropolitan area in 2006

Take Beijing as an example. Due to eight consecutive years of drought in the upper reaches of the Chaobai River and the upper reaches of the Yongding River from 1999 to 2006, Beijing The eight-year average water inflow of the Miyun Reservoir, the city's main water source, is less than one-third of the annual average level in the 1990s (equivalent to a normal water year), and the Guanting Reservoir is only 41%, and the surface water supply has been greatly reduced. In order to overcome the water resource crisis, Beijing has taken measures such as strengthening water conservation, raising water prices several times, and reducing water consumption in some industries, resulting in the city's total water consumption falling from 4.05 billion m3 in 2000 to 3.43 billion m3 in 2006, a decrease of 15%. At the same time, it vigorously introduced foreign aid. In 2003, Beijing opened two emergency underground water sources, Pinggu and Huairou, and provided emergency water from Cetian Reservoir in Shanxi, Huliu River and Yunzhou Reservoir in Zhangjiakou, Hebei four times in 2003, 2004, 2005, and 2006. Adjust water.

According to relevant research and analysis, the available local surface water resources in Beijing in 2020 are approximately 1.14 billion m3 and 820 million m3 in normal water years and dry years respectively, and the available groundwater resources are both 2.4 billion m3. The total amount of locally available water resources is approximately 3.54 billion m3 and 3.22 billion m3 respectively, and the water resource gaps are approximately 1.623 billion m3 and 2.183 billion m3 respectively.

According to the requirements of Tianjin’s economic development plan, Tianjin’s total water demand in 2005 was 4.711 billion m3, and the overall water shortage was 2.353 billion m3, accounting for 49.90% of the water demand. Among them, urban water shortage was 976 million m3, accounting for 49.90% of the water demand. 41.48% of the total water shortage, with rural water shortages of 1.377 billion m3, accounting for 58.52% of the total water shortage; Tianjin's overall water shortage in 2010 was 2.763 billion m3, accounting for 54.00% of the total water shortage, of which 1.357 billion urban water shortages m3, accounting for 49.11% of the total water shortage, and rural water shortage is 1.406 billion m3, accounting for 50.89% of the total water shortage.

In 2005, Tianjin’s total water supply was 2.358 billion m3, of which urban water supply was 1.031 billion m3 and rural water supply was 1.327 billion m3; in 2010, Tianjin’s total water supply The total water supply is 2.349 billion m3, of which the total urban water supply is 1.031 billion m3 and the total rural water supply is 1.318 billion m3.

Through the above analysis, it can be seen that Tianjin is short of water resources and has a serious imbalance between supply and demand.

The proportion of groundwater extraction in the Beijing-Tianjin-Hebei region continues to increase, from 67% of the total water supply in 2000 to 72% in 2006. Due to the reduction in recharge such as precipitation infiltration, groundwater levels have increased. keep falling. Groundwater has been over-exploited and aquifers have been depleted in some areas. Calculated based on the average exploitable amount of groundwater over the years, the over-exploitation of groundwater in the Beijing-Tianjin-Hebei metropolitan plain in 2004 has reached 4.155 billion m3, forming an area of ??7,500km2 (4,052km2 in Hebei Province) in Beijing, Tangshan, Baoding, Shijiazhuang, Suning, etc. There are shallow groundwater funnels and deep groundwater funnels of 21,400 km2 (44,000km2 in Hebei Province) in Tangshan, Tianjin, Langfang, Hebei Zaoheng, Cangzhou and other places. The shallow groundwater funnel centers in Beijing and Shijiazhuang reach 44m and 51m (404km2) respectively, while the deep groundwater funnel centers in Tianjin, Hebei Zaoheng and Cangzhou reach 98m, 77m (2001km2) and 81m (1370km2) respectively. Excessive exploitation of groundwater has led to the depletion of some aquifers, causing ground subsidence. The ground has dropped by 3 meters in Tanggu, Tianjin, and 2 meters in Cangzhou. Hazards such as seawater intrusion, downward movement of salt water, and environmental desiccation have also occurred. The depletion of aquifers has caused the Haihe River basin plain to lose water security reserves (Table 2.11).

Table 2.11 Groundwater overexploitation in the plains of the Beijing-Tianjin-Hebei metropolitan area in 2004 Unit: 100 million m3

Note: *Includes shallow groundwater and deep confined water extraction; **Shallow The multi-year average exploitable amount of groundwater in the layer is calculated, and the exploitable amount of deep-seated confined water is not included in the calculation.

Data source: Beijing Statistical Information Network, 2005.

The above situation shows that the urban water supply guarantee rate in the Beijing-Tianjin-Hebei metropolitan area is not high. When encountering consecutive dry years, a series of emergency measures still have to be taken. The consequences of doing so often exacerbate ecological deterioration.