Static pressure decreases pump work

[humbleguy]

Hey just wanted to know the theory behind this. If i have a open reservoir say 20 ft above a pump and i want to pump the water that flowing down on the suction side to a reservoir on the discharge side 80 ft above, the static pressure from the suction reservoir should decrease the pumps work,but will the static pressure be enough to make the water level rise on the discharge side of the pump with no work from the pump?

 

[brewnog]

No, of course not. You need the pump to do work to move your water uphill.

 

[xxChrisxx]

With 20 ft of head, you will get a 20 ft column of water meaning the pump has to make up there difference.

 

[humbleguy]

With 20 ft of head, you will get a 20 ft column of water meaning the pump has to make up there difference.

Okay so your saying the equilibrium height of the water on the discharge column will be 20ft above the pump, same as the height of the water on the suction side?