Overdrafting Chinas groundwater resources

According to a comprehensive survey completed by the Ministry of Water Resource in 1996, the overdraft of groundwater was one of China's most serious resource problems (Ministry of Water Resources and Nanjing Water Institute, 2004). Although we do not know the exact way in which the survey was conducted, the results of the survey provide evidence that groundwater overdraft is a widespread problem and may be getting worse. According to the report, overdraft is occurring in more than 164 locations and affects more than 180,000 km2. The areas of overdraft range from 10-20 km2 to more than 10,000 km2, and are in 24 of China's 31 provinces. Groundwater overdraft is affecting all types of aquifers: the shallow groundwater table (87,000 km2), the deep groundwater table (74,000 km2) and the aquifers that have two layers, both the shallow and the deep (13,000 km2).13 Since the 1980s, the annual overdraft of groundwater has averaged about 7.1 billion cubic meters. In the late 1990s, the annual rate of overdraft exceeded 9 billion cubic meters. More than one-third of the volume of overdraft is from deep wells, many of which may be non-renewable on a short timescale.

Although the problem of overdraft is usually discussed in general, it appears to be particularly acute in cities. The Ministry of Land Resources has recently finished an evaluation of groundwater resources in China (Ministry of Land Resources, 2005). According to the final report, groundwater resources in most large and middle-sized cities in northern China are either in overdraft (extractions exceed recharge) or in serious overdraft conditions (the fall of the groundwater table exceeds 1.5 m/year).14 For example, in many cities the volume of water extracted from the aquifer is nearly double the volume of average annual recharge.15

Such dramatic numbers for all of China, especially for urban areas, are the cause of the concern that has appeared in the literature. However, when analysing the effect on rural areas, at least according to NCWRS data, a somewhat different picture arises. According to our data, there was no fall in the groundwater table in 25-33% of villages in northern China using groundwater in both 1995 and 2004.16 In 8.5-16% of villages (between one-third and one-half of villages that reported no fall in the groundwater table) respondents told the enumerators that the groundwater was actually higher in 2004 than in 1995. In another 10-17% of villages, the average annual fall in the groundwater table was less than 0.25 m/year. In other words, in more than one-third to one-half of China's villages using groundwater over the last decade, groundwater resources have shown little or no decline since the mid-1990s. Although, (based on our data, most villages are in or nearly in balance) we are not arguing that groundwater problems do not exist. In fact, there are still a large number of villages in which the water table is falling. Before classifying these villages as being irrational groundwater resource exploiters (although some of them may be), it is important to remember that a village's water resources may not be over-exploited even if the water table is falling. Given the fact that many of China's aquifers are fossil, by definition, any meaningful extraction will result in declining water levels. Hence, even under the most rationally planned groundwater utilization strategy, there will be a share of villages in China in which we should expect the water table to be falling. In addition, if we follow the Ministry of Water Resources (MWR) definition of serious overdraft, only 10% of villages using groundwater in the last decade have water tables that are falling at a rate faster than 1.5 m/year. Such a decline rate is not only serious, but also a crisis.

In summary, then, the point we want to make is that in many places -indeed, in most places in northern China - it is possible that water resources are not being misused. However, we do not want to minimize the problems that are occurring in some places. There are a large number of rural areas in which the water table appears to be falling at a dangerously fast pace. Where the resource is being misused, steps will be required to protect the long-term value and use of the resource. However, it is important to realize that many of the required measures (discussed in the next section) will have associated costs - to obtain adoption and productivity, and to avoid reduced income. Because measures to counter overdraft are not needed in all villages, leaders should not take a one-size-fits-all approach so that they can avoid inflicting unnecessary costs on producers in communities where overdraft conditions do not exist.

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