Groundwater is a vital source of fresh water for agriculture, industry, public supply, and ecosystems in many parts of the world. In the North China Plain, more than 60% of fresh water comes from groundwater, and agricultural irrigation in this area relies heavily on groundwater.The amount of groundwater stored in North China decreased over the last decade, according to a study published in Water Resources Research recently.

Wei Feng and colleagues used satellite gravity measurement from GRACE mission to hunt the groundwater storage changes in North China over the last decade. The findings demonstrate how satellite data can be used to study the spatial-temporal variations of groundwater water.

“According the GRACE measurements and simulated soil moisture data, North China is losing the groundwater at a rate of 8.3 km3/yr, which is about three times higher than the estimate from official groundwater bulletins. The difference between our estimate and the official result indicates the potential deep groundwater depletion in the plain and piedmont regions of North China.” said Wei Feng. The largest groundwater depletion is located in the piedmont region of Taihang Mountains, where the irrigation is highly depended on groundwater. Even if we apply the low bound of our estimate conservatively, the study region lost approximately 50 km3 of groundwater between January 2003 to December 2010, he said, which is greater than the capacity of China's Three Gorges Dam, the largest power station in the world.

Spatial patterns of groundwater storage trends estimated from GRACE-SM data(a)CSR, (b)GFZ, (c)JPL and (d)forward modeling over the time period of 2003-2010