Steady-State Drawdowns in Coupled Aquifiers

The analytical linear solution that predicts the steady-state drawdowns for a coupled two-aquifer system in which pumping from an underlying artesian aquifer is balanced by a reduction in evapotranspiration from an overlying water-table aquifer was developed. An example illustrating how the drawdown equations can be used to determine whether significant drawdowns will occur in the water-table aquifer is presented. These drawdown equations can be used for preliminary analysis and planning studies and to test the convergence of digital model solutions when these more sophisticated techniques are warranted. A major limitation to using these equations is that the predicted water-table drawdowns cannot be so great that evapotranspiration would cease altogether and, thus, could not be reduced any further to balance the pumping.