Example $6\mathrm{.}9$: An earth dam is built on an impervious foundation with a horizontal filter at

the base near the toe. The permeability of the soil in the horizontal and vertical directions are

$3{10}^{-2}m\frac{m}{s}$ and $1{10}^{-2}m\frac{m}{s}$ respectively. The full reservoir level is $30$ m above the filter.

A flow net constructed for the transformed section of the dam, consists of $4$ flow channels and

$16$ head drops. Estimate the seepage loss per metre length of the dam.