Groundwater storage and depletion trends in the Loess areas of China

Groundwater is the essential source of drinking and irrigation water supplies in most parts of the world. The Loess area is one among the largest manufacturers of agricultural merchandise in China and is to a great extent dependent on groundwater for public water supply and irrigation. The effect of expanded open supplies and irrigation on groundwater levels has not been very much investigated, both spatially and temporally. Thus, this study has used remote sensing data from NASA’s Gravity Recovery and the Global Land Data Assimilation Systems to assess the aggregate change in groundwater storage across the Loess area over a period of 13 years, from 2002 to 2014. The results demonstrate that the total groundwater depletion occurred at the rate of 529.73 km³ yr⁻¹, and the mean groundwater consumption rate was −3.89 cm yr⁻¹ between the winter and monsoon seasons during the period of 2002–2014. The most extreme consumption rate occurred during 2004 (−7.60 cm yr⁻¹), while the minimum occurred during 2003 (1.13 cm yr⁻¹). Groundwater consumption at such high rates will prompt unsustainable groundwater levels, bringing about financial anxiety, vulnerability to environmental change and excruciating burdens to sustenance and water security. Careful assessment of spatiotemporal groundwater storage in the Loess area will help China’s water resource managers and policymakers administrate groundwater resources in the future to improve water and food security.