Hey
To increase the head of the pump you have increase the diameter of impeller not the motor.
Usually to increase the discharge reduce the diameter and to increase the head increase the diameter of the impeller. Keep in mind this is the thumb rule
making pump house lay out is not big problem. engineering man can easily do it. first of all we have to select the pump and motor. then we have to take size from the manufactures. Then we have to selcect the correct range of electrical panels and the sizes too.
Then you have to see no of pumps...