A well at a distance d from an impermeable boundary at a flow rat Q. The head and any point (x, y) is given by the following equation:

Where C is a constant, r1 is the straight line distance from the well to the point (x, y), and r2 is the distance from the image well to the point (x, y). The y-axis lies along the impregnable boundary. Use Darcy's law to show that the flow across the boundary (y-axis) is indeed zero?

x,y) =