Surface Irrigation

A farmer has $32mm$ diameter siphons operating with a $20cm$ siphon head. Determine the

number $$r $32mm$am$$ter $$non pipes req$$red to supply $5\frac{l}{s}$ to an irrigation border.

marks$)$

An irrigation basin measures $20m(L)5m(W)$ and is supplied in $2\frac{l}{s}$ stream size $(q_e).$

From first principles, determine the set time $($ min $)$ to apply $25mm$ irrigation depth.

$(3$ marks$)$

A border irrigation system is on a clay soil with a $1$:$150$ gradient. The dimensions of the

individual border are $200m$ long $2m$ wide border Assume the resistance to flow from the

crop to be high $(n$ value $=0\mathrm{.}15).$

a$.$ What should the stream size and cut off time be in order to uniformlv abplis f ${?}^{-}$siuso

Application of $20mm?$

$(4$ marks$)$

b$.$ If you later learn that the maximum flow that can be supplied from the water source is $80$

$m^3*h{r}^{-1},$ what options do you have to achieve an application that is close to the Gross

Application target of $20mm,$ while maintaining a Distribution Uniformity of $80\%$ or higher?

$(3$ marks$)$