Example $5\mathrm{.}3$

A permeable soil layer is underlain by an impervious layer, as shown in Figure $5\mathrm{.}7$a$.$ With $k=4\mathrm{.}8{10}^{-3}c\frac{m}{sec}$ for the permeable layer, calculate the rate of seepage through it in $\frac{m^3}{h}\frac{r}{m}$ width if $H=3m$ and $=5.$

Solution

From Figure $5\mathrm{.}7$b and Eqs. $(5\mathrm{.}13),$

$i=\frac{\text{H}\text{e}\text{a}\text{d}\text{l}\text{o}\text{s}\text{s}}{\text{L}\text{e}\text{n}\text{g}\text{t}\text{h}}=\frac{L^{\text{'}}tan}{(\frac{L^{\text{'}}}{cos})}=sin$

$q=$kiA$=(k)(sin)(3cos)(1)$;$k=4\mathrm{.}8{10}^{-3}c\frac{m}{sec}=4\mathrm{.}8$

${10}^{-5}\frac{m}{sec\text{;}q}=(4\mathrm{.}8{10}^{-5})(sin5)(3cos5)(3600)=0\mathrm{.}045\frac{m^3}{h}\frac{r}{m}$

uarr

$To$ change $to$

$\frac{m}{h}r$

Ground surface