Inter-seasonal and geodynamics-related gravity changes are important geoscientific signals that are extractable from gravimeter observations after removing background information as local hydrology gravity effect. With two superconducting gravimeters (SGs: OSG-053 and iGrav-007) located in different tectonic units, continuous global navigation satellite system data and absolute gravity observations, Wuhan, China, is an ideal location for investigating the effects of gravity resulting from significant local hydrology mass variations. We have processed approximately 26 months of gravity data collected from the SGs in Wuhan and obtained residuals of −40  nm·s−2 for OSG-053 and 100  nm·s−2 for iGrav-007. The hydrological observations indicate an estimated gravity increase of 42  nm·s−2 near iGrav-007, which mainly results from an increase in unconfined water level with an aquifer-specific yield of approximately 0.1. However, the gravity changes around OSG-053 are mainly from soil moisture and reach −90  nm·s−2⁠. The soil type, thickness, and water content parameters are obtained from hydrogeological surveys and drilling data. The deep confined water level rises by 2.5 m, which introduces a 1  nm·s−2 gravity variation with a specific storage approximately 0.00001 from the field unsteady-flow pumping test. The modeled gravity is approximately −40  nm·s−2 around OSG-053 and 90  nm·s−2 around iGrav-007, in accordance with the observed gravity variations. The difference in gravity changes between the two SG observations can be explained by different local water storage environments. Our results suggest that unconfined and soil water significantly impact the in-situ gravimetry, and that further detailed hydrogeological surveys are required. A combined investigation of gravity and water levels can be a useful approach for monitoring aquifer storage conditions and groundwater management.

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