Estimating groundwater storage changes in the Heihe river basin using grace

As a typical inland river basin in the arid region of northwestern China, the Heihe river basin (HRB) can only provide limited available surface water resources, resulting in overexploitation of groundwater resources. In this paper, temporal and spatial variations of groundwater in HRB are derived from GRACE. This approach is successfully employed in HRB thus offering new insight into monitoring groundwater variations in a river basin with limited or even without any observed data. Our analysis indicates that groundwater storage in HRB reaches its highest peak in 2005 summer, and then begins shrink and no increase in 2008. Spatially, groundwater shows decline in upper HRB in first two years and slightly increase in following years, which is opposite to that in middle HRB where groundwater slightly increases in 2005 and then declines in following three years. In lower HRB, GRACE detects a continual increase in the total 6 study years.