A Considevation of mechanism of land subsidence during the rising period of piezomtric head in aquifers

During the rising period of piezometric head within the confined aquifers of the multiple aquifer-aquitard system due to the regulations against groundwater withdrawals, land subsidence and delayed uplift of the ground surface have been observed in Niigata plain since about 1965. In order to explain how this phenomena can occur, a discussion of the mechanism of aquifer-aquitard system response to piezometric head changes is presented in this paper by introducing the concept of residual excess porewater pressure and through use of two constant storage coefficients for aquitards