For the quasi-three dimensional ground water model or the three dimensional groundwater model

it is difficult to determine the hydrogeologic parameters for aquitards. The stress-strain diagram method introduced in the paper is an effective method to estimate aquitard parameters. Firstly

the principle of the method is introduced. Then the elastic and inelastic specific storage and vertical hydraulic conductivities in aquitards in Shanghai area are estimated by the method using the subsidence and hydrograph data. The results estimated by stress-strain diagram method provide good start parameters for numerical modeling of land subsidence in Shanghai area. For aquitards

the aquifer test analysis is ineffective; and the laboratory soil test method is also ineffective if there are no soil samples of the aquitards. However

the stress-strain diagram is useful

when the observation data of subsidence and water level of aquitards are available.