considered at a distance of x on the other side of the line of zero drawdown. The distance of the observation well from the pumping well is r and from the image well is r'.

For the steady state condition of a confined aquifer, the drawdown at the observation well can be obtained as

                                                                     (21.2)

                                                                                     (21.3)

                                                                            (21.4)

For the unsteady condition, the drawdown at r at any time t can be obtained as

                                                                  (21.5)

                                                                   (21.6)

Well near an impermeable boundary

Fig. 21.6 shows a well near an impermeable boundary. In this case, the actual drawdown at the

• Fig. 21.6 Well near an impermeable boundary