groundwater

[Thatguy]

Does it have what could be called a "pressure", or just GPM?

 

[Valveman]

Pressure increases by 1 PSI for every 2.31' you go below the surface of the water, the same as it does in the ocean. The amount of flow you can produce without decreasing the bottom hole pressure to zero, is the gallons per minute a well will produce.

 

[Sponsor]

 

[Thatguy]

So a pump just below the well water's surface would produce less/more/the same GPM & PSI as a pump 10' or 20' below the surface? My pond pump seems to deliver more GPM as the pump is placed deeper but one formula seems to say it makes no difference.

 

[Valveman]

With a submersible, depth below the water surface increases the NPSHA. But as long as the submergence is deep enough to prevent a whirlpool, NPSH doesn't mean much to a sub.

 

[Thatguy]

This experiment probably agrees with what you just said.

IIRC, when the pond water level is lower the pump delivers less GPM to the fixed height waterfall but when I just now raised the pump to just below the water's surface it made no significant difference in the waterfall GPM, and this agrees with the formula.