A flow net is a graphical solution to the Laplace equation for two$-$dimensional flow for

flow through a homogenous, isotropic $($kh $=$ kv$)$ medium. Applications of Flow nets include

estimate:

of SEEPAGE under impermeable and through permeable dam structure.

leakage$/$ SEEPAGE into empty tunnels and out of water filled tunnels

leakage$/$ SEEPAGE from water reservoir.

The flow nets can also be used to calculate the pore pressure on the dam construction. The pore

pressure and total potential are related according to:

$=+$

where

H $=$ total potential

z $=$ the distance to the point of interest below reference$/$datum level

$=$ pore water pressure at the point of interest

$=$ density of water

$=$ acceleration due to gravity

If you know the total potential at a point of interest you can also compute the pore pressure

at the same point.

Task: Consider a flow net below. Estimate the pore pressure at point A