Question $6$:

$($Value: $20$ marks$)$

The flow net for seepage through the foundation soil under a concrete dam is shown

$($i$)$ Determine the total seepage through the foundation soil in cubic meters per day per meter of dam, if the coefficient of permeability for the foundation soil is $25{10}^{-6}\frac{m}{s}$

$($ii$)$ Calculate the effective stress at point $A$ if the total unit weight of the soil is $19k\frac{N}{m^3}.$

$($iii$)$ Calculate the maximum exit gradient. If this gradient is assumed to be greater than the crtical hydraulic gradient, what effect could it have on the dam?