Irrigation system from lake

[Andy]

I have a house which is about 300 feet from a lake and would like to take irrigation water from the lake.

It is about a 10 foot rise from the lake to the house level.

I would appreciate any comments on the following possible approaches.

1) Put the pump near the lake and run 300' of 3/4 pipe to the house. This requires 300' of buried UF to the pump, which cannot be buried in the same trench.

2) Put the pump near the house and run 300' of 3/4 pipe to the lake with a foot/check valve at the lake end. Have a spigot tap at each end of the 300' intake pipe for initial priming. (Using a garden hose and city water for priming)

3) Putting the pump halfway in between and running UF to the pump and 3/4 intake and output lines as needed, with foot/check valve.

My preference is for number 2 since it only requires one pipe trench and no buried UF electric. I think that with only a 10' head and a check valve, it should maintain a prime....

Thanks for your comments on the above...

Andy

[Doug Miller]

#3 seems to have the disadvantages of #1 without the advantages of #2.

#2 looks better IMO... but I really think you'll want a larger pipe. 3/4" is awfully small for a hundred yard run. I'd use 1" at least. This is, for the most part, a labor-intensive job with modest materials costs (except for the pump itself). The difference in cost between 3/4" and 1 1/4" isn't all that great, and there's no extra difficulty in laying the larger pipe.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[Kyle Boatright]

Some thoughts...

1) Pumps push better than they pull.

2) You can buy a pump with a gasoline engine, and run it when you need - this eliminates an electrical trench, but probably reduces the convenience of use.

3) If I was you, I'd go with your first option.

KB

[Edwin Pawlowski]

Still the best option.

Foot valves stick open, get clogged. Pumps to not pull very well if they lose their prime. IMO, in the long run you will n ot be happy with this setup.

Looks good on paper, but get one tiny pebble in the foot valve and this theory no longer works. I know, you'll have a strainer. Eventually things get by it, seals wear.

[nicksanspam]

The Hazen-Williams equation says 300' of 0.75" smooth pipe with a 5 gpm flow has a 0.0004227x300x5^1.852x0.75^-4.871 = 10 psi pressure loss...

1" makes 2.5 psi, 1.25 makes 0.84, and 1.5 makes 0.347.

If one end of the pipe is always under lake water and the flow is shut off while the pipe is full and the pump runs every week or two, this might work fine with a leaky foot valve.

Nick

[gfretwell]

Where does this myth come from?

There may be some utilities that don't want co-mingled services in a right of way but it is certainly not a code requiremernt. The real problem with this plan is voltage drop. If you ran a 240v pump and #10 wire it should be OK though. I do agree you need bigger pipe ... for the same reason you need bigger wire.

300' is a long way

[Tony Hwang]

Hi, Before anyting else, can you draw water from the lake? Is it allowed? Tony

[Sam]

Who's going to know it if you do it right?

[Tony Hwang]

Hi, Know? Environmental concerns for one. If everyone starts drawing water, the lake may disappear over time. It happened where I live. A big lake disappeared from too much acerage development. No more water in the lake. Tony

[MC]

The pump needs to be as close to the source of the water as possibe, I recommend no further than 10 feet from the source (can have longer pipe out into the lake as long as not out of the water)

If there is access to do so I would have the electic utility run a seperate line and meter to that location with an outside breaker box to run the pump. They would need access to read the meter, must be a sutable drive.

If that is possible, I would then run a low voltage wire pair to the pump to control a pump relay. I would run 12-10 size wire for that distance. There may be some sort of radio control options that would work.

I would go with a high volume/low pressure pump of about 1-1/2 hp and run a

1-1/2 to 2in line to reduce friction. Really depends on what your water demands will be.

Also filter the water real good if using any gear driven sprinklers, sprays or drip.

If need more pressure can always install another pump of same type at the other end for boost, about a 1 hp should do.

MC

[Andy]

loss...

Andy replies:

Thanks for turning me on to the Hazen-Williams equation, which now is a part of my engineering program collection..... This was a good way of showing the increase of performance with increase of pipe size.... (My background is EE, and this Civil E stuff is handy to know)

And thanks to all who replied . Lots of advice here, and I will be considering it all before I start digging a trench....

Regarding putting elec and water in the same trench, I realize it is

not an NEC requirement, but local municipalities often have increased restrictions..... Since I live in a rural area, I will probably use a single trench regardless.... unless I have several hours left on the trencher, in which case I will go from the other direction and use the dirt from the second trench to fill up the first (grin).....Besides, it's fun to use a trencher.....

Regarding taking water from the lake. It is permitted here if you own shoreline property, providing one buys a permit from the water district.... This lake has 330 miles of shoreline and is unlikely to run dry from watering my lawn, which runs back into the lake anyway.....

Thanks again to all who replied. I will even consider digging a well with a shovel. Might do that anyway, just to see if it works.

Andy in Texas (retired engineer)

[Ron Bridwell]

[royroy]