Gas powered water pump questions

[hartmacw]

You do not have to use the same size pipe for an entire run. In some circumstances, it is common to use differing pipe sizes, although that is usually more often with elevation changes or other things different from your circumstances.

Water flowing through pipes is subject to friction loss, as the water bumps up along the internal wall of the pipe as it moves along. Using the same pump, if you pump through 50 feet of pipe, the velocity of water coming out the end of the pipe will be much greater than if you pump through 500 feet of pipe.

But, as ponytug also pointed out, it may be disadvantageous to use a gas powered pump moving water directly from the pond all the way onto your garden and out the sprinkler heads. Every time you wanted to water the garden, you would have to go start the pump. Then let the pump run while you water the garden, then go shut it off. If it were me, I would want something requiring less frequent attention. Also, the pump would likely have a lot more capacity than just running a few sprinklers-- so you would be burning gas somewhat inefficiently.

As an alternative, the gas pump could (quickly) fill a holding tank near your garden. Then you would shut the gas pump off. Depending on size, that amount of water might last several days or more without firing the gas pump up again. An electric pump could take the water from the holding tank, pressurize it, and run the sprinklers. That sort of arrangement could also be operated on a traditional irrigation timer. An advantage would be, depending on size of your holding tank, you might not need to run the gas pump for several days, or maybe a week or more.

Finally, if you want to run sprinklers directly from the gas pump in the pond, lots of calculations of pipe size, friction loss, gpm per sprinkler, etc. are needed to ensure success. If the gas pump just fills a holding tank, you need not bother with almost any of that. Because the gas pump will push water to the holding tank-- the only variable being the speed it achieves to fill it.

Hope that helps.

Outstanding, thanks. This has been a super helpful conversation for a newbie to the world of water pumps. I told my wife I was looking for a water cannon that would just shoot the water over the barn onto the garden 500' away and she just looked at me with the rolled eyes and said, that ain't happenin'. She actually considered the possibility I was serious.

 

[plowhog]

super helpful conversation for a newbie

When it comes to moving water, I think most of us are newbies. I've been at this for years and there are still many mysteries.

Good luck with finding the best route-- have you considered wireless transmission of water he he.

 

[Larry Caldwell]

If you have a water shortage, you might consider eliminating the sprinkler, which is very water inefficient. Go to drip irrigation instead. Soaker hoses are cheap, and you can put them on a timer. If you lay a strip of plastic mulch over the hose, you can reduce evaporative loss to almost nothing, and it will also prevent weed growth. I use a cheap mechanical flow meter on the feeder hose that will limit the amount of water applied at any one time, and I never end up leaving the water running. The flow rate is minimal, so a garden hose provides plenty of water.

 

[denchen]

In theory you should be able to pump water over an indefinite distance. But frictional loss and change of height stop this. Frictional loss is caused by many things but primarily the internal condition of the hose/pipe is the biggest drag. Loss is increased proportional to the speed of the water [velocity], so if you have a big pipe, the speed will be lower for a given amount of water, that can be increased at the end of its travel if you wish. Water is almost non compressible, so if you were to block the pipe at the end, the pressure would be the same through out it`s full length. Let the water run, and because of the frictional loss [drag], the pressure decreases.

 

[hartmacw]

If you have a water shortage, you might consider eliminating the sprinkler, which is very water inefficient. Go to drip irrigation instead. Soaker hoses are cheap, and you can put them on a timer. If you lay a strip of plastic mulch over the hose, you can reduce evaporative loss to almost nothing, and it will also prevent weed growth. I use a cheap mechanical flow meter on the feeder hose that will limit the amount of water applied at any one time, and I never end up leaving the water running. The flow rate is minimal, so a garden hose provides plenty of water.

I don't disagree with you at all and in fact I do use soaker hoses in my cantaloupe and watermelon patch. One of my biggest areas of need though is a relatively good sized popcorn patch. At the distance I plant my rows I'd need over 600' of soaker hose just for the patch, plus it's another 200' of hose to run to the nearest water source at the house. I have to keep that patch a good ways from my veggie garden so the popcorn doesn't have a chance of cross pollinating my sweet corn.

 

[Larry Caldwell]

I don't disagree with you at all and in fact I do use soaker hoses in my cantaloupe and watermelon patch. One of my biggest areas of need though is a relatively good sized popcorn patch. At the distance I plant my rows I'd need over 600' of soaker hose just for the patch, plus it's another 200' of hose to run to the nearest water source at the house. I have to keep that patch a good ways from my veggie garden so the popcorn doesn't have a chance of cross pollinating my sweet corn.

Unless you are saving seed, cross pollination will not affect the popcorn. Pollination is for the next generation. Plant popcorn next to the sweet corn, and just buy certified seed next year.

 

[Midniteoyl]

have you considered wireless transmission of water he he.

Thats always worked for me..

 

[hartmacw]

Unless you are saving seed, cross pollination will not affect the popcorn. Pollination is for the next generation. Plant popcorn next to the sweet corn, and just buy certified seed next year.

Yep I save a gallon of seed back every year after I shell it to replant. I haven't bought popcorn seed for probably 6-7 years now.

 

[Sberry]

Loss depends on how much you are pumping, 5 gpm thru a 2 inch is different than 50 or 100. Reducing to a 3/4 at 500 will result in a drip at 5gpm really, lots of pressure at the start very little at the end. When watering with a well its ideal to make it run 100% by sizing the sprinks so they run just enough to keep it from reaching shut off pressure. I run 8 9/64 to run 45 and 7 will run at 50 or so. I have gauge in my shop at wash sink so we can see well status at any time.

 

[Sberry]

I water yard from well, too complicated to move pipe around. I have a V8 running right now at about 1000gpm 75# or so.