Problem $3$

Water is to be distributed to $70,000$ people from a service reservoir using the transmission pipes

shown schematically in the Figure below. The average per$-$capita demand is estimated to be

$600\frac{L}{d}\frac{?}{?}$ person, with $50,000$ people supplied from the connection at point $B$ and $20,000$ people

supplied from the connection at point $C.$ The transmission lines consist of $1200-mm$ diameter steel

pipe with a typical roughness height of $1mm,$ the length of pipe from $A$ to $B$ is $5km,$ and the length

of pipe from $B$ to $C$ is $7km.$ It is estimated that the water demand will fluctuate such that the

maximum$-$day factor is $1\mathrm{.}8$ and the maximum$-$hour factor is $3\mathrm{.}25.$ The design fire flow in the service

area that is connected to $B$ is $15,000\frac{L}{m}in,$ and the fire flow for the service area connected to $C$ is

$10,000\frac{L}{m}in.$ Under design conditions, the pressure at B is to be no less than $550$kPa, and the

pressure at $C$ no less than $480$kPa. The two pumps within the system are to be selected such that

they operate at their maximum efficiency, and these pumps will both be driven by $1200-rpm$ motors.

$($a$)$What are the design flows for lines $AB$ and $BC?($b$)$ What specific speeds and pump types are

required? Explain clearly what you would do with this information. $($c$)$What volume of storage

reservoir is required?