Watering lawn from Pond - what is needed

Larry_Van_Horn · Apr 21, 2004

This might seem like a stupid question, but wanted to know if there was anything that I was missing. I will be planting about 3 acres of grass - too far away from the house, and want to make sure it lives. I have a 2/3 acre pond - 13 ft deep that has good water running into it. The thought was to buy an inexpensive gas pump from Northerntool, and a couple of sprinklers on stands. I was going to just run this as needed. Anyone do anything similar and have I missed anything?
Thanks,
Larry

MossRoad · Apr 21, 2004

A filter/strainer, a pump, some hoses and sprinklers... sounds pretty simple to me. You might want to look into the well pumps that are made especially for lawn irrigation, too. Could be useful in the future.

Larry_Van_Horn · Apr 21, 2004

Yeah, seems pretty simple though I was also wondering about how I might have to figure out sufficient line pressure to get the sprinklers to work. Is this a concern?

Dozernut · Apr 21, 2004

I use a Honda WX10 pump to water remote areas. The pump is 4 cycle, 31cc, and has a one inch hose. Very light and portable and will run about an hour on a tank of gas. Just drop the suction end into the pond, hook up the sprinklers, Prime it and fire it up. This little pump will handle three sprinklers at a time, anymore and it does not have enough volume. Here is a site that has pictures and pricing.
http://www.mayberrys.com/honda/waterpumps/html/generalpurpose.htm

fishman · Apr 21, 2004

Larry,

Three acres!? You are going to need more than two sprinklers unless you want to move them a lot.

I did that last year on a much smaller scale and will be doing so this year as well. I use a small Honda 4 stroke pump (wx-10) which attaches right to a garden hose. I use some sprinkler heads I found at Home Depot that are just small little metal jobs 3" by 2" with a hole in the top leading out from a chamber. They cost about $3 and don't get clogged no matter what. Throw about a 40' radius under good pressure.

I have to worry about head loss because my lawn is uphill from my water source about 50 vertical feet and requires about 250 feet of hose. After that much travel, my output is pretty anemic, let me tell you. But pondwater is so much better as compared to chlorinated tap water. My garden is a lot closer and lower in elevation and I water it as well.

In your case, sounds like you need a bigger pump with a 2" output hose running to somewhere in your 3 acre lawn, perhaps 1/3 of the way in. Then you'll need a manifold which I've heard can be manufactured from pvc pipe. Several spigots are attached to this manifold to distribute the water via garden hose to your various sprinklers. If you have regular sprinklers, a prefilter would be a good idea on the intake side of your pump, but I don't have any experience using one.

In any case, you do need to be concerned about head loss if your pump run is long. Be sure and use 5/8 garden hose to minimize loss after the manifold.

And don't worry about pumping down the pond. There's a lot more water in there than most people realize.

Oh, and please take pictures of your project. Especially the manifold/sprinkler setup. I've been wanting to try something like this, but don't really know how much better performance a 2" hose hooked to a manifold would yield vs. my small simple system.

Maybe someone will weigh in that has actually done something on the scale you're talking about.

fishman · Apr 21, 2004

Mossroad, could you elaborate on the well pumps you are talking about? Are you talking about a jet pump (I think that's the correct term). Basically high pressure, low volume, high head? Do you think something like that would work in my situation described above?

Don't mean to hijack Larry's thread, but I bet lots of folks are interested in this subject.

RobertN · Apr 21, 2004

Filter, pump, pipe, sprinklers....

Start with the sprinklers. Figure out how much water they will require, what thier reach is ect. A good place to start is the Rainbird catalog.

If you know what your water requirements is, you can get a pump that will supply the requirement. Your requirement will also affect the size of pipe from the pump to the sprinklers. 3 acres covers some distances; your friction losses will need to be considered. A 35A-TNT will run 51' at 60psi, at 7.8gpm or 49'@50psi, 7.2gpm. A 65PJADJ-TNT will get you 65', but needs 16.5gpm@80psi.

For irrigation, rule of thumb for PVC pipe is 5gpm for 1/2" pipe, 10gpm for 3/4" pipe, 15gpm for 1" pipe. On top of that, it may need bigger diameter to overcome friction losses over distance.

3 acres is a fair amount. You need big heads, big pipe, and a big pump...

RobertN · Apr 21, 2004

50' elevation will lose you about 21.7psi right off the bat! Elevation changes alone will cause a pressure loss or gain(depending on uphill or downhill) of 0.433/ft. I'm guessing that pump does not put out high pressure to begin with???

Bigger hose/pipe can flow more gpm, and has less friction loss per foot. But, it is all rather dependant on the specific type of hose or pipe. For instance, 3/4"' class 200 PVC has a larger inner diameter than 3/4" schedule-40 PVC. The bigger inner diameter will flow a little more water with less friction loss.

_RaT_ · Apr 21, 2004

Robert has it well figured out. Your GPM will dictate how many heads you can run, the pressure you have is measured two ways. The pressure the pump can pump up two and the pressure you will have at the sprinkler when all the sprinklers are operating. Impact heads, the RainBird type that make the noise, typically don't require as much pressure as the gear driven. They also handle dirty water better. I use the Model 65 from RainBird Robert mentioned. It does require a lot of water, has great throw and is used on my portable sprinkler stand with a 3/4" hose. I use what is called ditch water. I pay for it, but it is brought to me with about 120 PSI. I use a couple of Spears band filters to filter out the occasional pine needles etc., that get into the system. You should plan on experimenting a little with the pump. Get some large hose, at least 3/4" because the pressure drop due to friction loss will be immense even in just a 100' length. Pressure drop is something very few folks think about until you start running larger GPM. What it boils down to is the velocity of the water through the pipe or in your case, perhaps a hose. The higher the velocity, the greater the pressure drop. Too much pressure drop and your sprinklers start performing very poorly making you think you needed a bigger pump. If you get a chance, stop by a irrigation supply house that carries RainBird or Hunter. Pick up the catalog that shows all the various equipment and pressure drop figures for each class of pipe. It's interesting once you get into it. Good Luck, you won't need it though. /forums/images/graemlins/wink.gif