Using river for irrigation system...

[julz6769]

A nice guy from another site recommended I post my question over here...

I need advice about pumping systems coming off of a large river. (going to irrigate a 4 ac. pasture. I'm allowed 125 gpm, I'm going to use approx. 100. I've got 23 feet of lift and a 500 ft run. The river level does fluctuate seasonally. I'd sure appreciate any first hand advice from anyone experienced in this application. Thanks!

[hoskm01]

Are you loking for pump reccomendations, methodology to the install? All of the above?

[FIMCO-MEISTER]

River pumping from the few I've seen requires a lot of experience. Someone who knows your river. I'd definitely find a pro. I've seen some terrible self done river pump jobs.

[AI Inc]

Remember , pumps do much better pushing water then trying to pull it.

[julz6769]

I've installed systems off of lakes and ponds, but never off a river with strong currents and large fluctuations, so I'm researching the best way to stabilize the pump. For the gpm and lift I need, I'm pretty sure I need a submersible, but again this is a large river with big currents. I just wondered if any you guys have any tips that might save me some headaches...lol. It's a challenge, but I like these kind of jobs.

[Wet_Boots]

Do you have any definite idea of the high-water elevation, and how much the river can drop from there?

[Mike Leary]

What river is it?, I know that area.

[ARGOS]

I hate to ask, but is this legal?

[julz6769]

It's the Snake river outside of Lewiston, ID. If the new homeowner doesn't exercise his water rights, he'll lose them. That's why I'm putting some effort into this. Yep, he's legally allowed to take 125 gpm. We'll pull the pump in the winter. What I'm finding is that this is a niche application. Ya either find the big guys with large farms with massive pump stations, but we're only talking 4-5 acres here. If I get a strong enough cent. pump I could always use a booster pump with it, right? What's hard is dealing with the current...

[Wet_Boots]

Work with me here. What's the variation in water level?

[julz6769]

Thanks all for your replies. We're not sure at this point, but right now I believe it's approx. 10-12 feet. You wouldn't happen to know a good way to get this down to a better number, do you?

[Mike Leary]

Is it going to be a ag application?

[Wet_Boots]

If you are working with a range of 12 feet, or even a bit more, it would not be impossible to have a centrifugal pump, and a booster, installed above high-water mark, and to use a flexible intake to a floating screen.

[FIMCO-MEISTER]

The Snake can be a pretty vicious white water river at times right? A submersible pump would get washed down the river the first year I'm betting. I don't know how you would anchor the thing. 220/120 in the river as well. I don't know much about this stuff but I know you've got a challenge. Is that 125 gpm max but as much water as he wants?

[Wet_Boots]

That's why I think a centrifugal would make more sense. Bolt it to a concrete pier poured in place. Maybe a couple more poured anchor points to chain the intake strainer to.

[Mike Leary]

That's why I think a centrifugal would make more sense. Bolt it to a concrete pier poured in place. Maybe a couple more poured anchor points to chain the intake strainer to.

Most of the river pumps I've seen are done that way.

[Wet_Boots]

As long as the variation is less than 15 feet, that gives you some wiggle room to locate pump(s) above high water, and still not have to lift water as much as 20 feet. 100 gpm will make for a big suction line.

[julz6769]

Yeah, I'll have to use a two pump set up. I'd hate to see a thousand dollar pump washed away! lol... Nobody else wanted to mess with using his river water,( I do see why) but he really wants to preserve his water rights. Use 'em or lose 'em. I'll get it done one way or another. I just hope I get this job after all of this figuring! The name of the game, I suppose! lol

[FIMCO-MEISTER]

Can't he sell his river rights? If he doesn't need them but is just using it for the sake of property rights it seems like a very expensive way to hold onto your water rights. I guess it does add value to the property.

[Mike Leary]

Can't he sell his river rights? If he doesn't need them but is just using it for the sake of property rights it seems like a very expensive way to hold onto your water rights. I guess it does add value to the property.

Welcome to the great west, Peter.

[Wet_Boots]

Every home needs a water feature.

[julz6769]

Well, he does have two wells at only 18 gpm. I'm going to give him that option, but he really does want to take advantage of his water rights. And no, his water rights are not transferrable. They go with the property. If he doesn't use them, he loses them forever. They were established by a previous owner back in the 70's. I was supposed to meet with him today to give him prices but he decided to change it until tommorrow morning. Hopefully he'll have a little cove along the bank or somewhere ideal to locate a pump. That would sure make it easier.

[Wet_Boots]

Just remember that there's a limit to how high you can lift the water, so your pump will be fairly close to the highwater mark.

[julz6769]

The lift is one of the bad parts that I'm stuck on. Guesstimating without further inspection I come up with approx. 23 feet. I need to go out there and get a better reading tommorrow. I'm concerned about the float intake set up. Lot's of figuring out to do.. I'll get exact measurements tommorrow...

[Wet_Boots]

23 feet is not good. You get near the point where a centrifugal pump won't operate.

[hoskm01]

Give him a wet well and a vertical turbine. Will take the river height fluctuations like a champ.

[Wet_Boots]

Can those be safely installed at an angle from vertical, to conform with a sloped riverbank?

[hoskm01]

Can those be safely installed at an angle from vertical, to conform with a sloped riverbank?
I doubt that. Never had it come up, but youd have to support the actual pump down through the well if it were at an angle. I reckon they need to always be straight up and down. If you could put the well maybe 30 feet back off of the bank of the river with a heftily sized pipe into the river at its low level, youd always have enough water in the well as you can operate your wet well at a wide range of levels. 10-12 feet, as OP stated, no problem.

[Wet_Boots]

Seems like a big project for four acres. Maybe just set up something cheap and simple to grab the water and pump it, long enough to demonstrate, and secure the rights.

[julz6769]

It seems simpler to me to pump up to a holding tank(s) then up again to irrigation point. Takes two pumps, but in the big scheme of things, shouldn't be a problem...

[ARGOS]

Ditto. Grab the water into holding tanks and do a secondary pump from there. Also howze about some sorta cove in the snake?

When I went to college at Wazzu we used to jump off cliffs into the snake...where was that? That was a blast.

[Wet_Boots]

For 100 gpm and a minimum 15 foot lift, you could just get by with a 5HP centrifugal. But with very little pressure to spare, and a need to size pipes to minimize further losses. Four acres of Maxipaws, anyone? :)

If I couldn't pour a support pier near the highwater mark, it might be possible to work out something with a 'sled' secured by chains and cables to a higher point.

[bigbuck1975]

Remember your hydraulic computations for friction losses in the pipe as well. At 100 gpm, you could have major friction losses.

If you choose to go submersible, you may find that the friction loss may play a bigger part in the sizing in the pump vs the elevation head.

Submersible would work in all situations, centrifugal could have issues.

[julz6769]

Solved the problem. Going to use a 7.5 hp two stage, two phase (power set-up). The pump guys at United Pump know their stuff. I would highly recommend! Ordering material today, gonna get going on this tommorrow. Thanks for all the replies on this subject. I'll post updates if I come across anything interesting along the way...

[Wet_Boots]

We like photos

[julz6769]

Okay, I can do that. I'm looking forward to this one. It'll be challenging fun!

[Wet_Boots]

By the way, no one here has yet mentioned the concept of "Net Positive Suction Head" so do make sure you have that covered. All pumps have their own curve for this.