need answer with steo by step

Design discharge is $54\mathrm{.}69$ lt$/$s

PROBLEM. $3$

Design the gravity$-$watersupply pipeline for a town whose future $($after $30$ years$)$ popuplation is of $21000$ with an average daily consumption of $150\frac{\text{I}}{?}$ pers.day. The internal diameter of the pipe is $D=30cm$ with William$-$Hazen friction coefficient of $C=140.$ As for the design critarion consider that $5\frac{p}{}80m$ and the velocity of $0\mathrm{.}75V2\frac{m}{s}.$ Assume that all pipes are of straigth line as indicated in the figure.

Note that in every condition $($considering maximum and minimun water levels in the reservoir, installation of check strucrures and valves etc.$)$ inconjunction with the design criterion the design discharge passes through the pipeline without any problem.