Study on Water Consumption Coefficient for People’s Living and Its Regional Disparity in the North of China

WANG Jing-ai1-3, MAO Rui3,4, YANG Ming-chuan3,4, ZHOU Jun-ju1

1 College of Geography & Remote Sensing; 2 Key Laboratory of Regional Geography, Beijing Normal University, 3 Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education of China, 4 College of Resources Science & Technology, Beijing Normal University, 100875 China

Abstract: By employing the information-reshuffling method that integrates census data, precipitation data and inquiry data of water consumption, this paper discusses (water consumption coefficient of people's living) in allusion to different precipitation zones and different periods of time. The study shows that (water consumption coefficient of urban people's living),  (water consumption coefficient of rural people's living) and increase with time passing, and the increasing extent of  is 1.84, 2.62, 2.84 and 2.68 times respectively from the west to the east, which results from the total quantity of water resources and the speed of urbanization. and of each precipitation zone increased with 85 increasing more quickly than , and the difference between the two also increased when time passed. In the past fifty years (1950-2000), the increasing extent of  was 1.71, 2.96, 2.41 and 2.33 times respectively from the west to the east, in which 200-400mm precipitation zone increased more than others. Meanwhile the increasing extent of  is 1.55, 1.60, 1.53 and 1.64 times respectively from the west to the east with each precipitation zone increasing similarly. The change of is due to the speed of urbanization and the stability of water resources. This study provides basis for calculating the water demand of people's living and revealing the impact of water demand of people's living on ecological drought in different zones.

Key words: The north of China; precipitation zone; water consumption coefficient of people's living

1 INTRODUCTION

Water shortage will be one of the common risks people have to face in the 21st century. China, a country with water shortage, possesses only as much as 1/4 of the world's mean occupation for every person and is enlisted as one of the thirteen countries where water is in a great shortage. Furthermore, in China, the water resources distribution has been terribly unbalanced from region to region. North China, covering 15 provinces, possessing 45% of the farmland and 38% of the population of the country, only owns 9.7% of the total quantity of water resources of the country (Jia and Ci, 2000). Meanwhile, there exists apparent aridification in northern China (Zhang, 1992; Fu and An, 2002; Shi,1990). The increase of population and the rising of people's living standard will lead to a great need for water resources and activate the conflict between people and water resources. Therefore, the research on water resources has been people's great concern.

The abrupt increase of water consumption for production and people's living caused by the increase of population has resulted in the shortage of fresh water resources and the terrible conflict with ecological water consumption. So, because of the terrible conflict between water resources and people existing spatial and temporal differences, a research should be performed to find out its spatial and temporal distribution regularities by investigating the spatial and temporal variances of water consumption of people's living and production in order to improve or adjust water consumption intensity and methods for the purpose of the regional sustainable development. In the traditional research on water consumption, researchers would put their emphasis on the water consumption for agricultural and industrial production rather than the spatial and temporal differences in the water consumption of people's living and in the water consumption in the rural regions. The current research will try to find out the water consumption coefficient through the investigation of the water consumption of people's living, and estimate the spatial variances and temporal differences of the water consumption coefficient between urban and rural areas at two spatial levels: the whole northern part of China and various precipitation zones. Therefore, some grounds can be provided to estimate what extent the total quantity of the water consumption of people's living and people's behaviors have affected the ecological drought.

2 DEFINITION OF WATER CONSUMPTION COEFFICENT

The previous research has shed much light on the water consumption of people's living, such as the quantity of urban water consumption of people's living (Xiang, 1995; Li and Liu, 2002), the quota of urban water consumption of people's living (Feng and Chen, 2002) and the management of water consumption (Mohamed A S and Savenije H H G., 2000), but it scarcely put their emphasis on the research of rural water consumption of people's living. Meanwhile, it is also noted by us that, because the following factors: people's living standard, people's living habits, the economic situation and the total quantity of water resources can lead to spatial variances and temporal differences, it is necessary to analyze the spatial and temporal differences of water consumption between urban and rural areas. Based on the previous research, the current research will define the water consumption of people's living to present spatial and temporal differences of water consumption between urban and rural regions so as to provide some grounds to estimate the quantity and the quota of water consumption of people's living in different precipitation zones.

The water consumption coefficient can be defined from different perspectives (see Tab.1). In the agricultural research, the water consumption coefficient is always related to the agricultural output and the quantity of precipitation. And, concerning the water consumption for industrial and living purposes, it is usually related to the production value and quota of water consumption per person. In the current research, the water consumption coefficient refers to the total necessary water consumption by a single person per day in a special region and ordinary social background, in the form of liter (L).

To define the water consumption coefficient in different regions, the researchers have chosen four precipitation zones in the north of China (100-200 mm, 200-400 mm, 400-600 mm, and 600-800 mm) to analyze the water consumption coefficient. In fact, various precipitation zones mean the differences in the total quantity of water resources. The more the total quantity of precipitation is, the more the total quantity of the water resources is; correspondingly the higher the water consumption coefficient, and vice versus. The evaluation of the water consumption coefficient of people's living in different regions can not only help to quantitatively present the contribution to the drought made by the total water consumption for people's living in the north part of China, but also help to compare their contributions to the drought in different regions with the same total quantity of water resources. For example, the water consumption of people's living can reinforce the ecological drought on condition that the total quantity of water resources is smaller and

the water consumption coefficient is higher. On the contrary, it will have little effect on the ecological drought, while others depend on the various situations.

3 DATA AND METHOD

3.1 Data Source

The current research concerns 13 provinces and autonomous regions: Xinjiang, Qinghai, Inner Mongolia, Shannxi, Shanxi,Ningxia,Hebei, Beijing,Tianjin, Liaoning, Jilin and Heilongjiang, which include 127 cities and cover approximately 5,310,000km2. The annual total precipitation in these regions descends from about 850 mm to below 25mm (ranging from east to west spatially).

Table 1. Concepts of water consumption coefficient

Data employed in the current research are mainly selected from the statistic data, the weather station data and investigation data. From the statistic data and the weather station data, the population and the precipitation are selected, and from the investigation data the whole water consumption for family use is obtained from the questionnaires.

The statistic data are collected from The Statistic Annuals of the concerned provinces (1985-2000), The Social Economic Statistic Annuals of the concerned provinces (1949-1984), and The Population Statistic Data of the concerned provinces (1949-1984), including more than 5,000 records. The precipitations (1961-2000) are mainly from the journal of meteorology edited by China Meteorological Administration, including 6,000 records. The investigation data are from the 1,157 valid questionnaires issued in the 13 provinces to elicit the facts and details concerning their daily and monthly water consumption, the well depth and the water consumption for irrigation and so on.

3.2 Estimation Methods

The estimation of the water consumption coefficient was performed in three phases: inquiry, sample sifting and calculation.

The First Phase: inquiry (Ding et al., 2003). The investigation was intended to gain enough samples and estimate the water consumption for every family, in which 13 provinces were involved.To make the data more reliable and continuous, the subjects are mainly the residents over 50 years old and are required to finish the questionnaires according to their own experiences.

The Second Phase: sample-sifting. Firstly, the unfinished questionnaires were discarded from the 4,000 collected ones. And then, based on the anomaly and variance through the calculation of the figures in the finished questionnaires according to the statistic regularities, the water consumption value which is lower than the physical need limits or whose anomaly is two times higher than the variance will be discarded, too. In this way, only 1157 valid ones remained.

The Last Phase: calculation for the water consumption coefficient. At first  (the water consumption coefficient of urban people's living) and  (the water consumption coefficient of rural people's living) of different zones are calculated by averaging the quantity of corresponding urban and rural people's water consumption by a single person per day, in the form of liter (L). At last  and  multiply the corresponding percentage of total population, and then add up the results. This method leads to  (average water consumption coefficient of people's living) for a region, in the form of liter (L) (See Fig.1).

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Fig. 1 The course of calculation for water consumption coefficient of people's living

4 DIFFERENCE ANALYSIS OF WATER CONSUMPTION COEFFICIENT IN VARIOUS PRECIPITATION ZONES

The estimation and analysis of the water consumption of people's living in the northern part of China and various precipitation zones have shown the dynamic process of the water consumption coefficient in the northern part of China from both the spatial perspective and the temporal perspective. And the estimation and analysis even provide some grounds for the estimation of the quantity of the water consumption of people's living and water resources distribution, and then also estimate to what extent the total quantity of the water consumption of people's living has affected the ecological drought.

4.1Water Consumption Coefficient of People's Living of the Northern China

From 1950's to 1990's, , and  of the northern China present an increasing trend and their increasing extent is 2.64, 2.48 and 1.64 times respectively. In every decade is lower than, and the difference between them increases with time passing.

The fact that in each decade  is lower than  is due to the following factors, such as people's living standards, people's living habits and the total quantity of water resources, so the total quantity of water consumption for urban people's living is always much more than that of rural people's. The reason why the difference between  and  increases is that the difference of water using technology increases (Qin and Wang, 2000). The water using technology determines the quantity of water consumption. According to the water consumption of urban people's living, the use of washing machines, dishwashers and showers leads to the increase of water consumption. Although the people's living standard and the criteria of using water have apparently risen with the development of society, the increasing speed of urban people is always faster than that of rural people. So the difference of water consumption coefficient between urban and rural people is larger than ever before.

Tab. 2 Water consumption coefficient of people's living in the north of China (L/P.D)

Decade

1950’s

1960’s

1970’s

1980’s

1990’s

27

32

39

52

67

14

15

16

19

23

17

20

23

33

45

4.2Water Consumption Coefficient of People's Living of Various Precipitation Zones

There are conspicuous differences in the total quantity of water resources among various precipitation zones due to the difference of annual precipitation. The total quantity of water resources influences people's living habit and water consumption coefficient. Based on the investigation about water consumption coefficient of people's living in 4 precipitation zones, this paper not only compares the contribution of different precipitation zones to ecological drought under the corresponding total quantity of water resources, but also facilitates the estimation of the quota of the water consumption of people's living. Because of the limited extent of investigation, this research only calculates ,  and  of 4 precipitation zones (see Tab.3).

The temporal and spatial disparities of the water consumption of people's living of the 4 precipitation zones (100-200mm, 200-400mm, 400-600mm and 600- 800mm) are listed in Tab.3 and Fig.2.

As is shown in Tab.3 and Fig.2, this paper elicits the following conclusions:

Tab. 3 Water consumption coefficient of people's living in different precipitation zones over fifty years (L/P. D)

Precipitation

Zones

Decade

100-200mm

200-400mm

400-600mm

600-800mm

1950’s

34

22

24.1

23

15

16.4

27

15

19.5

30

14

23.8

1960’s

30

22

23.7

25

14

16.4

32

15

22.1

36

14

28.2

1970’s

36

24

26.9

33

17

20.9

41

17

27.5

45

19

35.8

1980’s

40

29

32.9

51

20

30.9

53

18

39.6

53

20

43.9

1990’s

58

34

44.3

68

24

42.9

65

23

55.4

70

23

63.7

1) and  of various precipitation zone increase with  increasing more quickly than, and the difference between the two also increases when time passes.

2)  of different precipitation zones increased in the 1980's to 1990's more sharply than in 1950's-1970's ,which is due to the low standard of people's living and sanitary conditions in1950's-1970's than in the 1980 to 1990's. Meanwhile, the secondary industry and the tertiary industry impel the increase of water consumption coefficient. For example, the development of washing machine industry can drive consumers to use more water resource.

3) In all precipitation zones the most conspicuous change of  is in 200-400mm precipitation zone.  changed from the minimum in the 1950's to the secondary maximum in the 1990's and its increasing extent was 2.96 times. This is because in northern China the speed of urbanization has spatial difference, in which the west is lower than the middle, so it pushes the development of .

4) of all precipitation zones increases steadily, and in the past fifty years the of 100-200mm precipitation zone has always been larger than other precipitation zones, and they are approximately equal in  .It is because, in northwest rural population is less than other zones and most of them live in the oases where people can use water conveniently, and meanwhile, the quantity of water resources in north area is steady.

5) According to the research area, the increasing extent of  is 1.84, 2.62, 2.84 and 2.68 times respectively from the west to the east.Of all precipitation zones the minimum of 8 is in 200-400mm precipitation zone in each decade. From 200-400mm precipitation zone the differences of 8 between 100-200mm and 200-400mm precipitation zones decrease with time passing and the  of the two is to be equal, but forward east the differences of  among other precipitation zones increase with time passing. All of these trends arise because 200-400mm precipitation zone is the semi-arid zone as same as 100-200mm precipitation zone that has little water resources, not like the eastern part of China (400-600mm and 600-800mm precipitation zones) with much water resources. Based on the distribution of water resources above and urbanization speed that rises from west to east, there exists 3 patterns: the west part of research area has little water resources and low urbanization; the middle part has little water resources and moderate urbanization; and the east part has much water resources and high urbanization. Thus, of 200- 400mm precipitation zone begins to be equal to the west part of research area, but the difference with the east is larger than before, because its urbanization speed is higher than the west part of research area but lower than the east part of research area.

Fig. 2 Spectrum of WCC of people's living to various prcipitation zones

5 CONCLUSIONS

1. By employing the information-reshuffling method that integrates census data, precipitation data and inquiry data of water consumption, this paper shows the time series of water consumption coefficient of people's living, which implies the spatial and temporal disparity of water consumption coefficient. This method can objectively reveal and reflect the spatial and temporal disparity of water consumption.

2. Based on the former research on the applied water consumption coefficient, this paper elicits the concepts of  (water consumption coefficient of urban people's living),  (water consumption coefficient of rural people's living) and  (water consumption coefficient of people's living), designs the calculation model for water consumption coefficient of people's living, and then calculates these coefficients.

3. With time passing by, ,  and of the research area increase sharply, and the increasing extent of  is 1.84, 2.62, 2.84 and 2.68 times respectively from the west to the east, which results from the different zone combination of the quantity of water resources and the speed of urbanization.

4. and of each precipitation zone increase with  increasing more quickly than , and the difference between the two also increases when time passes. In the past fifty years (1950-2000), the increasing extent of  is 1.71, 2.96, 2.41 and 2.33 times respectively from the west to the east, in which 200-400 precipitation zone increases more than others. Meanwhile the increasing extent of  is 1.55, 1.60, 1.53 and 1.64 times respectively from the west to the east with every precipitation zone increasing similarly. Change of  is due to the speed of urbanization and the stability of water resources.

5. After bringing forward and estimating the water consumption coefficient of people's living of the North of China above, this study can facilitate the calculation of the water consumption of people's living and the quota of water demand for people's living, and can supply a model for calculating other water consumptions of people's living. In the future researches, it is important to take into account of water consumption for the benefit of mankind and society, which may provide basis for calculating the impact of people's activities on ecological drought.

Acknowledgments

The research is supported by Projects NSFC-40271005 and NKBRSF-G1999043406-03. The authors thank Liu Wenzheng and other reviewers for helpful comments and suggestion on an earlier version of the manuscript.

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