Using Totes for irrigation supply--Questions:

[Qapla]

Keep in mind that above ground jet pumps are not designed to "pull" water for any distance ... they do, however, "push" water quite well. I would place the pump as near the tanks as you can.

Also, since you can measure the amount of water in the tank(s) and know how many gallons are there and you can determine the GPM that the system is delivering, finding the time that it takes for the pump to empty the tank(s) is doable.

If you use an irrigation clock (controller) you could eliminate the pressure switch and tank completely. The irrigation clock will turn the system on and off for the specified time you program it and when you program it. They also have a "pump start" feature built into them.

This means that you can install a "pump start switch" to power the pump and the pump will only run when the clock turns it on and will turn off when the clock turns it off. As long as you use all the GPM that the system is delivering, pressure is not a problem. We have put in many such systems.

The length of the pipe runs after the pump are not that great of a concern. Any decent pump will be able to deliver enough water to run irrigation as long as the pipe size is correct for the system. If you are going to be delivering 20-25 GPM from your pump you will want 1 1/4" minimum coming from the pump. Feeding the pump with 1 1/2" or 2" is a good idea.

I would also recommend installing some sort of "back-flow prevention device" in the line that supplies the totes. You don't want anything to contaminate your drinking water.

 

[PatasColo]

Also, since you can measure the amount of water in the tank(s) and know how many gallons are there and you can determine the GPM that the system is delivering, finding the time that it takes for the pump to empty the tank(s) is doable.

If you use an irrigation clock (controller) you could eliminate the pressure switch and tank completely. The irrigation clock will turn the system on and off for the specified time you program it and when you program it. They also have a "pump start" feature built into them.

[...snip...]

I would also recommend installing some sort of "back-flow prevention device" in the line that supplies the totes. You don't want anything to contaminate your drinking water.

I like the idea of the irrigation clocks to automate the start and stop of irrigation. However, I would not rely on them as the sole controller for either filling or emptying the totes. If there is ever a case where the flow rate changes or the amount that a tank is filled is not what is expected, you will either run a pump dry, deadhead it, or overflow your totes. (Any obstruction in flow or a lower supply of water in the well or lower head pressure could all cause these.) A system that reacts based on the level of water in the tote is a safe backup (e.g. float switch).

One of the simplest and most reliable ways to prevent backflow (and well contamination) is via a siphon break built into the system between the well and the first tote. A simple implementation of this would be to have the well supply going into the top of the first tote. Then, there should be a tote overflow below the level of the inflow, but above the level of water you desire in the tote. There are also some nifty & simple ways to make sure that end of the well-supply pipe remains underwater (even when suspended above the level of your tote water) using a water trap (a partitioned box, or other plumbing-based trap that keeps water blocking the end of the supply pipe). The siphon break cannot fail the way a mechanical backflow preventer might. I like it because it is simple and reliable. :thumbsup:

Best to you. I'll be interested to see what you finally implement.
-Mitch

 

[Qapla]

It is true that an air gap is the most effective back-flow prevention. However, you will still need some device to turn the water on before the air gap.

Also, keep in mind that a single check valve is not sufficient for safe back-flow prevention. They do make a "double-check" back-flow device. Since you are not trying to use the 10gpm flow to directly irrigate, the RPZ (reduced pressure zone) back-flow would work quite well. They are approved for use with potable water.

I do wonder why you don't have a larger pump down that 4" well. Does the well itself only produce 10gpm or is it because you have a 1/2 hp pump that has a low flow rate.

I recently installed a 1 1/2 HP @ 20gpm flow that only cost $425. With 20gpm you would not really need to go through all the expense and work of converting the totes, plus you still need to buy another pump to use the totes.

I also installed another pump that was 2 HP @35 gpm. It will deliver the 35gpm at 50 PSI with no problems.

Also, have you thought of using a rotor (Hunter/Rainbird/K-Rain) instead of impact style. Impact heads tend to use more gpm then the smooth operating rotors made by the mentioned brands. They also have changeable nozzles so you can adjust the amount of water each head is using.

 

[AlanB]

Funny I stumbled in this evening and this was up. Similar to what I have been padiddling with lately trying to make work on several levels.

Thoughts in Random order.

500' is an awful long way to pull, much better to push.

Irrigation pumps that I am familiar with at the nursereys etc. we work with seldom have pressure tanks. But they are also "ON" and valves open.

I am working on an engine driven pumping unit, will probably end up much like a "turbo turf" unit (google is your friend)

I am using the totes as "rain Barrels" and then need to pump up to the trailer with more totes.

As was stated there is a simple float valve available at TSC etc. for about $10 that does watering troughs that should work for your auto shutoff. You could also do the float valve switch like is used in a septic pump, basically just a float that is hooked to a male female plug that your pump is hooked into.

Consider staging your tanks progressively higher, it would give some advantages (and some disadvantages such as loosing capacity)

State of Texas has some great water management stuff out there available for free.

The video "food production systems for a backyard small farm" has some neat stuff on rain collection and tanks (but many principals will apply)

Qapla, it is funny that you spoke of doing the rotors, we just did that last week, I built some conduit 3 legged stands with a vertical 3/4" pipe nipple at the apex, hose adapter on the bottom, irrigation rotor on the top. Easy to move, light weight, cheap, darn near infinitely adjustable and does not leave us the 6' diameter soaked ring that the impacts tend to give us. It works really nicely for us.

Good luck, would like to see what you are doing and will try and get up some pics of what we have going on, time is just so short though.

 

[ocaj11]

There are some great points being made. I appreciate all the info.

My well will only produce 10 GPM. I would LOVE to have a well producing 20-25 GPM. I would buy the necessary pump in a heartbeat.

We're eventually going to setup a container tree farm which is the real reason I dug the well. Watering my lawn is a bonus. I currently have two 5.5 HP trash pumps pumping water to my lawn from my 9-10 acre lake. That has allowed me to get about 3 acres of grass established this year. We seem to be in a drought every summer now, so my lake doesn't get replinished during the hot months. The well/tote idea should allow me to stop pumping water out of the lake and I can use the temporary pvc/water hose/impact sprinkler setup I have now to make sure the lawn survives through the summer. I will remove all of that when it starts raining again in the fall. I'll probably convert over to the rotor sprinklers for use next summer.

I could put the irrigation pump at the well/tote location, but I don't want to run another 500 feet of electric wire that far. If I locate the irrigation pump at the shop, I can run less than 100 feet of wire that I already have. Since the pump and water in the totes will be about level with each other, shouldn't the pump be able to pull the water through 1.5 inch pvc?

Another novice question: I have a 33 gallon air compressor tank sitting around. Can I convert this into a pressure tank for the irrigation pump? I'll purchase another pressure tank if needed, but that free tank is calling my name.

 

[boggen]

problem with air compressor tanks = metal. that can and will rust out. beyond that. you could use the air tank as a pressure tank. put tire nipple or (valve and air tool nipple and pressure gauge) on top of the tank, so you can adjust amount of air pressure in the tank. (if use use a tire nipple, you can use a regular air tire pressure gauge to find amount of air pressure in the tank.

i honestly do not remember the rule of thumb for setting amount of air pressure, for non bladder pressure tanks for water.

 

[AlanB]

You could use one of the trash pumps to send it the 500 feet to the tanks if needed.
You can always try it, then add something additional if needed.

I have been buying star water pumps from Rural King and they have excellent tech support, might ne worth a call to them and ask their reccomendations.

Basic rule of thumb I use is that it is always better to push then suck.

Personally I am also looking at a windmill to pump up to elevated storage then gravity back down to fields.

 

[PatasColo]

My well will only produce 10 GPM. I would LOVE to have a well producing 20-25 GPM. I would buy the necessary pump in a heartbeat.

Thus, the reason for the totes. But I agree with those who have said that you really don't need a pressure tank nor pressure switches for this setup. Just the well pump to get water into totes, some switches (float or other) to turn water on and off (discussed already in depth above), and another pump between the totes and the place you're irrigating to push the water through.

I could put the irrigation pump at the well/tote location, but I don't want to run another 500 feet of electric wire that far. If I locate the irrigation pump at the shop, I can run less than 100 feet of wire that I already have. Since the pump and water in the totes will be about level with each other, shouldn't the pump be able to pull the water through 1.5 inch pvc?

Best to heed the advice above about not trying to pull the water too far, but rather push it. A little more independent search on the internet confirms this. All that air in the very long pipe is very "elastic", and besides that, your pump will have to pull all that air through before it gets water... possible priming problems, and those pumps aren't really meant to pull air (I know, you could assume that once the pipe is filled, it will remain filled, or primed. Not the most reliable... sitting a day or two with 100's of feet of pipe, air is trying to be pulled in, and well... could work, but I think it'll give you headaches at some point when air gets in at the pump connection or elsewhere). Quapla's info on jet pumps is well taken too. I know you're tempted to only use the wiring you have, but your layout distances makes it look like a case of penny-wise, pound-foolish.

Another novice question: I have a 33 gallon air compressor tank sitting around. Can I convert this into a pressure tank for the irrigation pump? I'll purchase another pressure tank if needed, but that free tank is calling my name.

Reiterate: Make the system as simple/low maintenance as possible, with each pump starting and stopping as little as possible (makes pumps last a lot longer). A very small tank like that will have your pump cycling several times per minute (just an approximation here, but that 33 gal tank will only hold a part of that in water, since it also needs a significant volume of pressurized air, and if you're trying to irrigate the water at a rate of 10-20 GPM you'll need higher pressure to push it any distance through the heads, I'd say you're going to get no more than 5 gallons at the required pressure before the pump has to cycle on again... pressure tank really becomes worthless, and pump is constantly going on and off). You can find exact measures for this online, but I have one real data point with a small tank (I believe similar in size to what you are talking, maybe slightly smaller) we use to deliver around 4-6 GPM at 35-50 lbs pressure... jet pump cycles about every 30 seconds.

Summary: Put the pump out near the source (totes) from which it will be pumping water, and no need (nor benefit) to having the pressure tank.

Keep us updated on your progress/experience!
-Mitch

 

[PatasColo]

P.S. Another option is to rethink your location for the totes. You could put them within reach of your 100' of wire (and thus locate them with the pump that will use them as a source for irrigation). This way, your well pump is pushing the water up to the totes, and your irrigation pump is pushing the water out to the sprinkler heads. Just a thought.

 

[PatasColo]

Re: pressure tanks: Here is a quick data point for you: 32 Gallon Well Pressure Tank, 21" x 27.75"

Summary: 32-gal tank. Deliver 10.9 gallons water at 30-50lbs pressure. You'll need higher pressure to power more than one or two heads. I'm not sure on this, but I'm guessing that to maintain higher pressure in the tank, you will get less delivered at that pressure (?) - I haven't done the math. Anyone more knowledgeable, feel free to chime in.

:2cents: -Mitch