The application of electro-osmosis to dewatering of soil was largely developed by L. Casagrande.

Where the dewatering system consists of a number of closely spaced well points or wells a simplified solution can be obtained by considering the lines of wells equivalent to a linear drainage slot.

The electric models suggested by ohm, have the same geometric shape as the soil through which the water flows. And both Darcy and ohm’s law have corresponding analogous quantities.

The portion between any two successive flow lines is called a flow channel and the portion enclosed between two successive equipotential lines and successive flow lines are known as field.

Using the formula, hW = h -Z

According to practical suggestion given by A.Casagrande, every transition in the shape of curve is smooth, being either elliptical or parabolic in shape.

A flow net can be utilized for determination of seepage, seepage pressure, hydrostatic pressure, and exit gradient.

In 1956, chapmen developed an expression for finding the discharge qP from a partially penetrating slot in an unconfined aquifer from his model studies.

For fine-grained soils, the well point system can be extended by the vacuum method.

The equation hW=h – Z, can be used to plot pressure net representing lines of equal water pressure without the saturated soil mass since all the three quantities in the equation can be expressed a the percentage of total hydraulic head H.