Question $2(20$ points$)$

A $120$ m reach of sewer is to be designed with a flow capacity of $250\frac{L}{s}.$ The street elevation at the upper manhole is $90\mathrm{.}0$ m and lower manhole is $87\mathrm{.}60$ m $.$ Determine an appropriate pipe diameter and slope for this reach, and establish the pipe invert elevations at the upper and lower manholes. Assume a minimum earth cover of $2\mathrm{.}2$ m above the crown of the pipe. Draw the hydraulic profile of the manholes and the pipe.