The Solution is L$=10\mathrm{.}3$m;

A flow rate of $2\mathrm{.}19$ m$3/$s is required to fill an elevated tank from a supply reservoir with a maximum water surface elevation difference of $55$ m$.$ This is accomplished by installing a pump in an $80-$cm$-$diameter, rough$-$concrete pipeline that is $250$ m long. The pump is placed outside the supply reservoir $(0\mathrm{.}9$ m below the water surface of the supply reservoir$)$ and has a cavitation parameter of $0\mathrm{.}15.$ Determine the maximum distance in meters that the pump could be installed away from the supply reservoir $($i$.$e$.$ allowable length of the suction line$)$ without encountering cavitation problems. The only minor losses are a square$-$edged entrance loss and an exit loss. The water temperature is assumed to be $20\backslash$deg C$.$