Pump Size?

[Dirk Salmon]

I am getting conflicting opinions on whether or not a small 2 " Honda pressure pump will be sufficient to pump from a lake up a draw to some trees I have on an acreage above the lake. Distance is 450 feet and the elevation gain in that distance is about 60 feet. I have been told a smaller pump will do the job, but others have told me that I'll need to go to a larger irrigation-style pump that farmers use. Does anyone have any insight with regards to this? Is there a formula or something I can use?

 

[WorthFlorida]

You must look at the pump specifications. There will be a chart for gallons per minute (or hours) verses lift and discharge pipe size. I looked up a gas Honda pump at http://powerequipment.honda.com/pumps/models/wx10 and surprising it does state 121 feet of lift but not the GPM. It does show a number but it is for zero lift.

Your problem will be the elevation. 60 feet is a lot to push up plus 450 feet has a lot of resistance. Probably at least 2" pipe to get any amount of water to flow. However, you might get away with a smaller diameter pipe since you only would need to do drip type irrigation for the trees. Another fact of life (physics) is no pump can suck more that 25 feet in lift so your pump (gas or electric) will have to be at the lake. If you need to have the pump at the tree level you'll need a jet pump. The jet would have to be in the lake and two pipes from the pump to the lake but I think the 450 feet is too much. Jet pumps are used for domestic water needs with a pressure tank.

I also looked up a pump that is a typical 2 HP irrigation pump but it does not mention any kind of head lift on line. It's usually in the manual.

If you can go with electric, 2 HP at 240 volts will be needed to get any kind of decent water flow. Just have to look at the specification charts. There are 3 hp pump that will work at 240 volts but you'll need 10 gauge wiring. Above 3 HP you start getting into three phase motors, very expensive.

 

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[Valveman]

Most gas power pumps are high volume low pressure pumps designed to just move water a few feet out of pond or something. Jet pumps and submersibles can be high pressure low volume pump that can lift hundreds of feet. And it is always more efficient for a pump to push water like a submersible, than to suck water like a gas pump or shallow jet pump.

A little 10 GPM, 1/2HP submersible would deliver 15 GPM at 100' of lift. That should get it up the 60' and still give you 40' (17 PSI) for a drip system. It doesn't take a very large generator to run a 1/2HP pump.