1 The Current Status of Groundwater Exploitation and Utilization and Its Role in Economic and Social Development

1.1 The current status of groundwater exploitation and utilization

Since 1949, the quantity of groundwater exploitation and utilization has been rapidly increasing in China. In 1950s, there are only scattered and few groundwater exploitation. In 1970s, the production volume of ground water increased to 57 billion m³/a, and in 1980s and 1990s this volume reached 75 billion m³/a and 100 billion m³/a respectively. At present, 100 billion m³/a of groundwater is exploited every year approximately accounting for about 1/5 of China's total water supply. Groundwater resource is an important and irreplaceable support for economic and social development in China.

1.2 The role of groundwater in economic and social development

1.2.1 groundwater is an important constraint factor for agricultural development in Northern China

In 1998, with a cultivate area of 1.03 billion mu( 1 mu equals to 666.7 square meter ), food output(wheat, corn, jowar etc.) in Northern China accounts for 50-60% of national total quantity, although there are only 1/5 of the nation's water resources. Groundwater played an important role in continuous increase of the food yield in Northern China as well as in fighting against drought throughout China. In the early 1970s, groundwater began to be exploited in a large scale, and more than 4 million mechanically-pumped wells were used for irrigation. Groundwater had made great contribution to improving agricultural production, historically changing the format of transferring food from the south to the north and keeping the sustainable economic and social development.

1.2.2 groundwater is an important source for industrial and municipal water supply in China

At present, groundwater is used for industrial and municipal water supply in more than 400 cities and accounts for 30 percent of water consumption in those cities. The northern cities depend mainly on groundwater. In Huabei area and northwestern cities, the proportion of groundwater out of total water consumption reaches 72 and 66 percent respectively. This proportion, for example, is over 70 percent in Beijing, Shijiazhuang, Baoding, Hengshui, Xingtai, Langfang, Tangshan, and even reaches 90% in some cities. Groundwater plays an important and irreplaceable role in ensuring water supply safety in Chinese cities especially in northern cities.

Groundwater is a main water source for not only scattered drinking water supply across the country but also the urban domestic use. Groundwater is an important drinking water source in water-shortage mountainous regions and in poor water quality regions. It's also used for agricultural irrigation and eco-environment protection. Groundwater is irreplaceable in China's economic development, especially for its northern part.

2 Current Problems on Groundwater Exploitation

2.1 The distribution of groundwater exploitation is unreasonable, with characterization of regional overexploitation and great potentiality as a whole.

In China, the annual groundwater exploitation continuously maintains more than 100 billion m³ since the middle 1990s. At present, there are more than 400 million mechanically-pumped wells in China. Due to unreasonable exploitation layout, groundwater over exploitation exists in many areas along with continuous decline of groundwater table. However, the current quantity of groundwater exploitation accounts for only 30% of the total showing a great potential for further exploitation. Besides, it's estimated that exploitable groundwater in shallow aquifer is up to 260 billion m³/a, and exploitable fresh groundwater is 14 billion m³/a.

2.2 Groundwater contamination is serious

In the recent 20 years, groundwater contamination tends from the local to the regional, which is mainly caused by industrial "three wastes" , urban pollutant(rubbish, waste water), agricultural pollutant (pesticide, chemical fertilizer), and leakage from many scattered oil spill. According to an investigation of shallow groundwater quality in 118 major cities, groundwater in 97.5% of these cities have been polluted to various degree, 40% of the contamination is serious. Recent investigations show that shallow groundwater contamination is considerable serious in Huaihe basin with many components exceeding national quality standard for drinking water, such as three nitrogen, chloride, total hardness, fluoride, iron(ferric and ferrous), manganese, TDS, etc. Other investigations show that some "three-inducing" organic contaminates (carcinogen, teratogensis, and mutagensis) present in the groundwater in some highly-populated eastern regions. These contaminates include pesticide such as class benzene hexachloride(BHC) and dichlorodipheny trichlorethane(DDT), halogenated hydrocarbon compounds such as chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene, single aromatic hydrocarbon, aromatic hydrocarbon compounds etc. Detectable rates are 10%-20% on average, and reach 30%-50% or even more than 80% in some areas.

2.3 The deterioration of groundwater environment

Unreasonable groundwater exploitation and utilization in some regions caused a series of environmental geological problems such as water-table decline in a large scale, land subsidence, land fissure, karst collapse , seawater intrusion, etc.

2.3.1 Decline of regional water table along with the increase of depression cone

In recent years, Northern China suffered regional decline of groundwater table, with the increase of depression cone in some areas. According to incomplete statistics, of the total area of overexploitation, much more serious part accounts for 42.3%. There are more than 180 groundwater cone of depression across the country, approximately covering 190,000km², with an extreme that water table is loom in depth of 100m. The preliminary statistics indicates that groundwater tables are continuously dropping down in such provinces or cities as Hebei, Shanxi, Shandong, Beijing, Tianjin, Shanghai, and Heilongjiang. Many ground water cones of depression exist in the cities nearby piedmont inclined plains, Hebei plain is the most serious, where the cones mainly concentrate in the middle and eastern parts such as Cangzhou, Dacheng, and Hengshui, and the areas with more than 70m of hydraulic head drops mainly present in those regions with saline groundwater, such as Cangzhou, Hengshui, Dezhou, etc. The areas with 50-70m of drops mainly present in the central part of Huabei plain, and the areas with 25-50m of drops are mainly located in piedmont alluvial-proluvial fans, which constitute a strip across Yongqing, Baxian, Raoyang, Xinji, Ningjin, Longrao, Jize, and Guangping. For deep-storage groundwater, a multi-type groundwater depression cone has formed around Bohai bag, and four provinces Hebei, Beijing, Tianjin and Shandong, covering an area of 43900km²(where the groundwater table is under the sea level).

2.3.2 Unreasonable groundwater exploitation and utilization caused a series of environmental geological problems such as land subsidence, land fissure, karst collapse, seawater intrusion, etc. in some regions in China

Unreasonable groundwater exploitation and utilization caused a series of environmental geological problems such as land subsidence, land fissure, karst collapse, seawater intrusion, etc. in some Chinese cities. At present, land subsidence and land fissure mainly exist in China's central and eastern plains, where 50 cities in 16 provinces are found land subsidence. The accumulated land subsidence exceeded 2m in cities as Shanghai, Tianjin, Taiyuan, with the maximum of 3.1 m in Tanggu. The area of land subsidence covers 282.5km² in the cities of Suzhou, Wuxi, Changzhou, where the subsidence reached 600mm. In Hebei plain, the area of land subsidence is up to 5000km² . There are more than 1000 geosutures occurring at 400 sites in 200 counties of 47 provinces such as Hebei, Shandong, Henan, Shanxi, Shanxi, Ningxia. Geosutures are intensive and active in Fenwei basin, especially in Xi'an city where 11 equidistant large-scale geosutures exist. There are 7 20km-long geosutures in Dadong city, 453 geosutures in 60 counties in Hebei plain with the maximum length of 4km, 128 geosutures in 43 counties of Henan province, and 25 geosutures in Suzhou, Wuxi, and Changzhou.

Over 1,400 of Karst collapse occurs in Chinese 23 provinces, leading to more than 40,000 pits formation. Karst collapse widely present in Guangxi, Guizhou, Hunan, Jiangxi, Sichuang, Yunnan, and Hubei. It also occasionally occurs in Hebei, Shandong and Liaoning, causing serious hazards. Some karst collpse brought significant economic losses in places such as Tuomo town in Guilin, Luiajie and Fenghuo village in Wuhan, urban area in Xuzhou, Tai'an railwaystation, and Wafangdian in Dalian.

Seawater intrusion occurs mainly in Shandong peninsula, and Liaodong peninsula. In Laizhou bay, the area of seawater intrusion has exceeded 1000km² with potential area of 2400km² vulnerable to be intruded by seawater. In this region, due to seawater intrusion, more than 400,000 local residents suffered the shortage of drinking water, more than 8,000 mechanically-pumped wells become useless for its salinity, and more than 600,000-mu cultivated land could no longer be irrigated, resulting in food reduction of 300 million kilograms per year. Seawater intrusion also ever occurred in Haicheng district of Beihai city, Guangxi Autonomous Region and Xinmowan region in Hainan province. The area of seawater intrusion is still expanding in China.

2.3.3 Shallow ground water has not been well used, causing the deterioration of groundwater environment

In some regions of North China, surface water was massively utilized for irrigation. Due to very shallow groundwater table, intense evaporation made shallow groundwater more and more salty and then resulted in secondary soil salinization like He Tao plain where the surface water was transferred from The Yellow River for irrigation. In these regions, reducing the scale of surface water transfer and exploiting groundwater to suitable degree can not only lower groundwater table and then improve soil by reducing evaporation but also increase the runoff of lower reaches of the river. In the vast eastern plain region, because the shallow groundwater has not been exploited the groundwater environment is deteriorated and the surface ponding and flooding become more serious in Yangtze River delta, Pearl River delta, Yellow river - Huai river - Hai river plain.

3 Countermeasures on Reasonable Groundwater Exploitation

3.1 Adjust the distribution of groundwater exploitation, promote shallow layer groundwater exploitation, and reduce groundwater exploitation in over-exploitation areas.

At present, there are 80 billion m³ of shallow fresh groundwater, 9 billion m³ of slight brackish groundwater, and 5 billion m³ of brackish groundwater available for further exploitation in China's major plains (basins). From the point of sustainable utilization view, the exploitation priority should be given to shallow groundwater resource. Due to the shallow aquifer's fine particles, lower well yield, relatively bad quality, it has not been well exploited. Policy should be made to encourage the exploitation of quickly-renewable shallow groundwater.

In the areas where groundwater over-exploitation caused land subsidence or regional continuous drop of groundwater table exploitation should be strictly limited. By taking such measures as restricting or forbidding exploitation, groundwater resource and its environmental function will be gradually recovered.

3.2 Strengthen groundwater investigation and monitoring, insure reasonable exploitation

Reasonable groundwater exploitation and management require not only scientific evaluation on its quantity and quality but also a good understanding of the spatial and temporal evolution of exploited condition. Therefore, it's necessary to carry out long-term investigation and monitoring. Based on integrated research on various accumulated information, correct judgment can be made on issues such as whether or not an exploitation plan is reasonable, whether or not groundwater are polluted, how the groundwater exploitation affect the environment etc. At present, following work should be carried out as soon as possible:

3.2.1 build up dynamic groundwater evaluation system in important plains and basins, and provide scientific basis for reasonable groundwater exploitation and utilization

To provide scientific basis for reasonable groundwater exploitation and utilization, basin-scale groundwater investigation and evaluation should be strengthened, the rules and characteristics of groundwater cycle should be comprehensively understood and dynamic groundwater evaluation system in important plains and basins should be built up as well.

3.2.2 Strengthen the investigation and control of groundwater quality and contamination to ensure drinking water security

China has not yet carried out investigation on groundwater contamination nation wide. At present, groundwater contamination has become a hot issue affecting the sustainable utilization of groundwater. In view of that, the status and its evolution trend of ground water pollution across China should be found out as soon as possible. At the same time, a national program of groundwater protection and prevention from pollution should be set down and then carried out.

3.2.3 Carry out model projects of groundwater exploitation in water-shortage regions and endemic regions, ensuring drinking water safety

Based on comprehensive groundwater survey in endemic regions in western China, some model projects on drinking water safety should be built up. At the same time, overall programs of drinking groundwater exploitation and utilization should be established. These projects will provide technical support and experience for ultimately solving drinking water difficulty of local people.

3.2.4 Promote further groundwater investigation and exploitation in karst region of southwestern China, provide scientific basis for the integrated control of karst rocky desertification

Model projects of hydrological survey and groundwater exploitation should be continued, which includes completing the integrated hydrogeological survey on 1:50,000 scale, building up some model projects, providing scientific basis for the integrated controls of karst rocky desertification

3.2.5 Further strengthen hydrological survey for urban emergency water supply; draw up a special plan for groundwater reserve; ensure the safety of water supply

Groundwater has certain advantages for a short-term emergency water supply. Due to climate change, years with low rainfall present more frequently in many regions. Recently, serious water scarcity occurs in those traditional water-abundant provinces such as Zhejiang, Guangdong, Hainan, where drinking water is in shortage. At present northern China is facing continuous low rainfall years, with serious imbalanced demand-supply. Besides, emergent water-polluting accidents, war and earthquake also pose threatens to surface water supply. Under these circumstances, ground water, an irreplaceable strategic resource, can play a key role. The most direct solution is to in-situ exploit groundwater to ensure the safety of urban water supply. Emergency water supply project was implemented in Beijing, which contributed much to the safety of the capital water supply. In the following years, hydrological survey for emergency urban water supply should be further strengthened and special plans for different class of groundwater reserve should be established for emergent need.

3.2.6 Establish modern national-wide groundwater environment monitoring network, providing basis for sustainable groundwater utilization and effective protection

Fully using existing monitoring wells, based on results of completed groundwater survey, taking groundwater basin as work unit, overall plan of groundwater monitoring network should be drown up. Through reasonable optimization and supplementation, a modern monitoring network can be gradually established. With clear work division, mutual complementarity and totally shared information, the whole net is mainly constituted by national backbone net and supported by provincial net. The net will achieve effective monitoring and management of groundwater exploitation process, and provide powerful technical support for sustainable groundwater utilization in China.