The Yellow River basin in China – Part 3
This is the third of four posts regarding the Yellow River basin in northern China. Having described the geography and geology (Part 1) and the hydrogeology (Part 2), it is now time to look at the extent to which (a) the system is over-subscribed and (b) climate change is set to make the situation worse.
Overall Resource Assessment
There are nine major multi-purpose projects and hydropower stations constructed on the main stream of the Yellow River; and four under construction. The total capacity of the 13 reservoirs is (or will be) in excess of 56 billion m3; with in excess of 35 billion m3 of effective storage. The total installed capacity is (or will be) just over 9 million KW, with an annual average power generation capacity in excess of 34 billion kWh. This represents approximately 30% of the total capacity of the main stream for both installation and power generation and, as the YRCC point out, in addition to exploiting a latent natural resource this “…also brings tremendous comprehensive benefits in terms of flood control… siltation reduction, irrigation, water supply etc, which plays an important role in promoting national economic development and harnessing the Yellow River” (YRCC 2007d).
In 2000, a collection of research papers by Mengxiong Chen (former chief hydrogeologist within the Ministry of Geology and Mineral Resources) and Zuhuang Cai (a fellow-member of the Chinese Academy of Sciences) were published in Beijing in English. Within this volume, MENGXIONG (2000) presents a wealth of statistics for the entire country but, (unfortunately in the present context), not in a way that enables data for the Yellow River Basin as a whole to be extracted. However, he does highlight the fact that many “of the important cities in China… are dependent chiefly on groundwater”; a category in which he includes Xi’an and Baotou. Indeed, after noting that the demand for water in some cities including Xi’an is in excess of 1 million cubic metres per day, he also notes that “the growth of urban population and the rapid development in industry and agriculture, water demand has also increased by 40 times the output in the early 1950s” (MENGXIONG 2000: 35).
Growth in the industrial demand for water appears to be impacting on agriculture because, citing as an example the city of Cangzhou (on the North China Plain but outside the Yellow River Basin), Mengxiong and Zuhuang record that water levels in city wells have dropped 60 metres over recent decades; creating a large cone of depression in the area an leading to the failure of 38% of irrigation wells in the surrounding area (MENGXIONG and ZUHUANG 2000: 43). Therefore, although there is little or no published data for cities within the Yellow River Basin, given that Xi’an and Baotou have been highlighted, it would seem likely that similar problems may exist – or soon develop – in those areas and/or in proximity to other major centres of industrial development such as Lanzhou, Hohot, and Taiyuan.
According to the YRCC, up to the end of 1996, a total investment of 42 billion Yuan had been made by the State government in over 10,000 reservoirs of various sizes; over 33,000 pumping stations; and over 380,000 wells. Numerous irrigation projects have reduced the adverse impact of lower-than-average rainfall (YRCC 2007d).
However, this success has been achieved without regard to the sustainability or otherwise of such increased anthropogenic use of water (see the discussion of Groundwater Modelling results below).
In 1975, the Water Resources Protection Bureau of the Yellow River Basin was set up, which led to the beginnings of water resource protection in the form of water quality monitoring, environmental management, and scientific research. However, according to the YRCC, the water quality monitoring work in the Yellow River Basin actually started in 1972, under the auspices of the Department of Public Health; with the YRCC only formally taking over responsibility for the monitoring on the Yellow River in 1978. However, responsibility for water quality monitoring work on tributaries was transferred to the water conservancy and environment protection bureaux within provincial government (YRCC 2007d).
The major industrial centres within the Yellow River basin are Lanzhou, Yinchuan, Baotou, and Sanmenxia on the main river; and Xining, Taiyuan, Xi’an, Luoyang, and Tai’an on the tributaries (see WEN et al Figure 4 – below). Although population growth has been minimal, continuing urbanisation and the improved living standards have resulted in rapid increases in industrial development and agricultural production. Therefore, despite improved regulation over recent decades, large volumes of untreated industrial effluent continue to be discharged into the Yellow River and its tributaries, having a continued adverse effect on surface water quality (YRCC 2007d).
WEN et al Figure 4 Major cities in Yellow River basin
By the end of 1994, a total of 340 water quality monitoring stations (monitoring at least 40 parameters) and 30 laboratories had been established within the entire catchment. However, it would appear that this monitoring has only served to record a significant increase in effluent being discharged to surface water over time. The YRCC currently acknowledge the existence of at least 300 major pollutant sources on the Yellow River alone and, according to analysis of the 1997 water quality monitoring data, only 17% of the total river length has water of a quality that meets minimum drinking water standards; such that it is restricting economic development of the Yellow River Basin (YRCC 2007d).
Referring to his previous work and that of other fellow-contributors, Mengxiong also states that in more than 40 cities (across China as a whole) groundwater is polluted to varying degrees by harmful substances such as arsenic, chromium, cyanide, fertilisers, insecticides, mercury and phenols; and that such pollution is found in both shallow and deeper aquifers (MENGXIONG 2000: 36).
Having constructed their three-dimensional numerical groundwater flow model, Mori et al first simulated groundwater flow with no human intervention (no abstraction from either river or groundwater) and compared this to data for the upper and lower reaches of the catchment in the 1960s (for which sufficient reliable data are available) and obtained a good correlation with observational data (Mori et al. 2009: 136-40).
Much of the subsequent modelling work undertaken has focussed on the North China Plain, not strictly part of the Yellow River Catchment, because this is where population density and/or groundwater abstraction is greatest. This predicted that, if current abstraction is continued from the deep aquifer, a further drop of 1m per year should be expected. Whereas, if all abstraction were to cease, piezometric levels would recover in about 5 years (Mori et al. 2009: 140-43).
No modelling of future increased abstraction was undertaken. No reason for this is given and, although this may reflect unstated government policy regarding population and/or development control, it is hard to see how a moratorium on all abstraction could last 20 years.
However, as an indicative tool for the analysis of a problem, the results speak for themselves: Current rates of abstraction are unsustainable in the long-term.
Because of frequent droughts affecting flows in the Yellow River basin, government action has been taken at both National and Provincial level to put in place a variety of demand management measures, such as constructing water conservancy projects; improving irrigation efficiency; and soil conservation schemes (as discussed above).
As part of its 11th Five Year Plan (2006-2010) – indeed part of a more widespread acceptance of market economics – the Chinese Government has allowed the price charged for water used to be increased in order to moderate demand (YRCC 2007d).
Tomorrow, in the final part of this presentation of my essay on the subject of the water resources of the Yellow River, I will discuss potential solutions to the problems climate change is causing; and discuss the conclusions that can be drawn from all of the information presented. Furthermore, in addition to providing details of all the references consulted in the process, I will also offer an update on the situation since I wrote this essay in March 2011 (e.g. the 12th Five Year Plan published in November 2011).