A hydroelectricity plant is supplied from a resevoir via a pipeline 2km long and 2.5m in diameter. The pipeline terminates at the downstream end at in a control valve.
Under normal operating conditions the hydro plant runs with a steady discharge of 30 cumecs and the water level in the surge tank is 19m below the level in the supply reservoir.
Determine the minimum surge tank size if the max allowable height in the surge tank above the reservoir is 7.5m showing working?