Use of water balance calculation and tritium to examine the dropdown of groundwater table in the piedmont of the North China Plain (NCP)

Abstract

The groundwater table in the piedmont plain was only about 1-2 m in depth in the 1950s and 1960s, but it lowered dramatically afterwards to about 25-27 m in depth (currently 21-23 m above sea level) due to overpumping of groundwater and drought in the region. This change has adversely affected the sustainable development and food supply of this important agricultural area. The groundwater table at Luancheng Experimental Station of the Chinese Academy of Sciences, located in the piedmont, dropped from 39.36 m in 1975 to 21.47 m above sea level in 1999, at an average rate of 0.72 m/year. Water balance components, such as daily rainfall, pan-evaporation, and evapotranspiration (by lysimeter after 1995) have been recorded since the 1970s, and they were used as variants to simulate monthly water table change based on a physically based statistical model. Groundwater samples were collected during the period 1998-2001, and tritium was measured in the laboratory to trace the groundwater flow from the Taihang Mountains to the piedmont. A reasonable exploitation rate of 150 mm/year was obtained from the model by assuming the annual water table is constant. The recharge and groundwater flow from the Taihang Mountains plays an important role in the water balance of the piedmont area, and it was estimated to be about 112.5 mm/year by using the variation of tritium with the depth, which followed a good exponential function. The simple water balance calculation indicated that the water table could recede at a rate of 0.8 m/year, which is close to the actual situation.

Water footprint of crop production for different crop structures in the Hebei southern plain, North China

“…In 2008, the HSP produced approximately 2.7 × 10 10 kg of grain (accounting for approximately 5 % of China's total) that had a water consumption of approximately 3.0 × 10 10 m 3 (Yuan and Shen, 2013). The over-exploitation of groundwater in this region has had devastating consequences: the groundwater table has decreased by more than 20 m within the past 30 years (Chen et al, 2003). Because the WF of various crops is different and the crop structure of a region reflects the proportion of various crops growing within that region, the WF of the crop structure can illustrate the entire agricultural water consumption of that region.…”

Socio-hydrological perspectives of the co-evolution of humans and groundwater in Cangzhou, North China Plain

“…A high community sensitivity implies that humans feel the pressure of environmental deterioration, motivating them to restrain human activities to restore environmental health. The concept of community sensitivity was also used to analyze the switching of the support between flood protection and wetland preservation in the Kissimmee River basin, Florida (Chen et al, 2016). It can be incorporated into the Taiji-Tire model to improve its explanatory power on a specific human-water system.…”

“…Driven by the increasing demand for water resources as well as the need for combating drought, improper exploitation of groundwater resources has resulted in serious environmental crises, particularly in regions with primarily groundwater-fed irrigation (Taylor et al, 2013) including the North China Plain (NCP; Liu et al, 2001;Chen et al, 2003;Zheng et al, 2010). The North China Plain is an important agricultural region of China.…”

Impact of the changing area sown to winter wheat on crop water footprint in the North China Plain

“…It is one of the major food production areas in China, providing about 75% of China's wheat and 35% of its maize (Meng et al, 2012). The NCP is also amongst the global "hotspots" in terms of water scarcity (Chen et al, 2003;Gleeson et al, 2012). The agricultural sector accounts for more than 70% of total water use in the NCP, and groundwater has been the lifeblood of agriculture since the 1970s (Liu and Wei, 1989;Hu et al, 2010;Cao et al, 2013).…”

“…A decrease of 10 m in groundwater table was recorded across the NCP within 10 years (World Bank, 2005). Problems are more serious in the northern part of the NCP, in which there is less natural precipitation; the groundwater table at the Luancheng Agricultural Ecosystem Experiment Station has decreased by more than 20 m within about 30 years (Chen et al, 2003;Hu and Cheng, 2011), and the groundwater depression cones in Beijing, Shijiazhuang and Cangzhou continue to expand (Jiang and Zhang, 2004;Sun et al, 2011). Of the agricultural crops in the NCP, winter wheat plays a key role in the development of severe water scarcity and in the over-exploitation of groundwater, because more than 70% of irrigation water (blue water) is consumed by winter wheat (Li et al, , 2008Sun et al, 2010).…”